Document 7Mn2rm2eyVp9R6g97KX4mMKwa

FILE N AM E: Phenolic Resins (PHR) DATE: 1974 DOC#: PHR052 D O C U M EN T D ESCRIPTIO N : P atents from Bendix; from AS Bendix File W 2372 ganics. Vehicle tests also showed a reduction in noise levels, an unexpected bonus.' Semi-metallics are currently being pro duced for one domestic vehicle equipped with solid rotors. Combinations of organic and semi-metallic pads are being used on a domes tic station wagon, luxury car and several light truck applications. The use of semimetallics has also been expanded to the larger disc brakes currently released for heavy trucks. SMALL CAR SOLID ROTOR APPLICATIONS As previously discussed, one of the pre requisites of a friction material is its abil ity to resist wear under various temperatures it will experience in service. We also have seen that smaller cars equipped with solid rotors will subject the friction materials to a wider range of temperatures than the mate rials used on larger cars equipped with ven tilated rotors. It has been our experience that reasonably good predictions of durability life can be made knowing the wear versus tem perature characteristics of any material. The effects which rotor weight and brake configuration have on operating conditions can easily be observed or measured with a Full Brake Dynamometer. A procedure which has been used consists of a series of braking cycles at six different initial brake temperatures. Each cycle is comprised of 300 stops made from 50 mph at 12 f)psps deceleration. The time interval between stops is varied to maintain a constant initial rotor soak temperature. The initial rotor soak temperature is increased from 25O0 to 625F in 75 increments. After the 625 cycle, a 250 cycle is repeated to establish the low tenperature wear rate after severe usage. The linings are measured after each cycle and the incremental wear plotted. The total rotor wear experienced for the 2L00 stop test is also recorded. The data illustrated in Figure 7a, b and c, were accumulated using a 9" diameter solid rotor, 0.375" thick weighing 6 lbs. Wheel load used was 975 lbs. The results clearly show the wear superi ority of the semi-metallics over both the Class A and Class B organics. While the total rotor wear for both the Class A and Semi metallic formulations were comparable, the Class B materials showed considerably higher opposing surface wear. Another inertia dynamometer wear proce dure used by some European manufacturers to screen potential friction materials is a series of 1 cycles consisting of 250 snubs, from 50 to 17 mph (13 ft/sec^ deceleration) in which the time intervals between applications is held constant at 95 seconds. Temperatures generated on this schedule are relatively low, usually peaking at about 250F for the brake outlined above. As in the previously discuss- J. P. KWOLEK ed wear versus temperature data, the semimetallics showed distinct advantages over both the Class A and Class B organics (see Figure8). CLASS - A-ORGANIC Fig. 7A-Wear versus temperature, inertia dynamometer, 975 lb wheel load, solid rotor CLASS-B-O RGAU IC Fig. 7B-Wear versus temperature, inertia dynamometer, 975 lb wheel load, solid rotor FRICTION MATERIALS SEMI - M ETALLIC 2373 tests. The differences between front and rear brake mileage projections are due to the dif ferences in operating temperatures and lining availability. Rear brake operating tempera tures were approximately 100F below the front brakes thereby drastically improving the wear rates of the Class A organic. In the case of the Class B organic and semi-metal]ics, the lower rear brake mileage projections are the result of differences in available lining thickness. Fig. 7C-Wear versus temperature, inertia dynamometer, 975 lb wheel load, solid rotor Fig. 8-Incremental lining wear, inertia dynamometer simulation of 2800 lb G.V.W., sedan running low temperature durability In the introduction, front brake tempera ture profiles were outlined (Figure 2) for a durability test of a vehicle equipped with solid rotors having a brake test weight of 2800 lbs. Tests conducted on Class A, Class B organics and semi-metallics using this vehicle procedure have repeatedly verified that semi-metallies offer distinct improve ments in lining life. The results Illustrated in Figure 9 confirm the incremental wear rates previously found in ^ill brake dynamometer CLASS A CLASS B SEMI-MET Fig. 9-Mileage projections, 2500 mile dura bility test, 1973 sedan, 2800 lb G.V.W. The particular brake system evaluated utilized front brakes lined with pads 0.1+75" thick while the rear brakes had pads which were O.I85" thick. It is interesting to note that similar tests on larger cars equipped with ventilated rotors rarely show life pro jections over 30,000 miles. Significant reductions ir noise levels were noted when semi-metal]ics were compared to the Class B organics. While specific noise hunts detected brake noise ratings as low as "7" for the semi-metallics, the Class B organics showed unacceptable noise ratings as low as "1+" (see SAE J1060). Further improve- 2374 ment . in noise rating levels were achieved when typical U.S. type insulators were added to the back of the steel shoes. A series of vehicle tests were initiated over a year ago in Europe in which a new semi metallic formulation was installed on vehicles subjected to three different types of duty and were compared to a typical O.E. organic lining: 1. Taxi cabs having automatic and standard transmissions. 2. Rental cars. 3. Business travelers (described as country driving). The estimated annual driving ranges from 12,500 miles (20,000 km) for rental cars to 25,000 miles (^0,000 km) for taxi cabs and business travelers. The results tabulated below (Table 1) indicate the semi-metallies reduced lining wear rates significantly, show ing 250 to 430^ improvement. With respect to rotor wear the semi-metal lic offered similar advantages over the class B organic (see Table 2). SUMMARY The performance and wear advantages of semi-metallic liningc over conventional organic J. P. KWOLEK types have previously been established. More recent development has made them more compar able for initial friction and low temperature or initial wear characteristics. The high temperature wear capacity of semi-metallic linings enhances their potential for usage on smaller cars with solid rotor brakes. Actual vehicle comparisons have shown substantial improvements over Class B type or ganics for projected lining life, rotor life, and noise characteristics under a variety of usage conditions. The gains in lining and rotor life offer ed by semi-metallics would appear to make them a most viable and cost effective candidate for use on small cars with solid rotor brakes and relative small lining pad areas. REFERENCES 1. F. William Aldrich, "Semi-Metallics: A New Type of Friction Material." SAE Paper #710591, June 7-11, 1971. 2. G. R. Wynne, "Development of Police Car Brake Standards." SAE Paper # 7 5 0 3 9 7 , Feb. 24-28, 1975 3. Seong Kwan Rhee & John P. Kwolek, U.S. Patent #3,835,118, Sept. 10, 1974. Table 1 - L inin g Wear R ates (MM/lOOO Km.) Class B Organic (o .E .) Sem i-M etallics Taxi Cabs A utom atic Manual 6.5 4.0 1.5 1,5 Car R e n ta ls 1.5 0.5 Business T ra v elers 1.5 0.5 Table 2 - R ctor Wear R ates (MM/l0,000 Km.) Class B Organic (O.E.) Sem i-M etallics Taxi Cabs Automatic Manual 0.57 0.02 0.33 0.02 Car R e n ta l . 0.12 0.06 Business T rav elers 0.10 0.04 United States Patent nvj Rhee et al. Hi] 3,835,118 145) Sept. 10, 1974 54] SPONUK IRON FRICTION MATERIAL I" 5) Inventc- Seong Kwan Rhe*. Southfield. NKh . John I*. kwolek, Trov. \ Y Assignee The Bendix Corporation, South Bend, lnd Filed Ms> 14. 1973 Appi \ o 360,255 ! C.S Cl. ' In'.. ( I. " s ?ifl(! of Search 260-38. 51.:'/.. 106'36. vr- :oc. : i d r , c o s t 51 08 ' (' n '<. 1'u, 2:><1 Dl( :i-o.3s i^i' i 'i 'll-- *.l**X.4 x* References ('led l M i l D Si A U S P.A11. M S :; , <jug-,:. 2 . vi < Spoke. .. ii if, 'f- i1.434.99k .V 4 v :.:r: : w>u.!20 3/1969 Aldrich........................ |0 6 'H 1/19^0 G riffith................................ w i n 5/197: Clark.................................106. jf Primary Examiner--Allan Lieberman Asustant Examiner--P R. Mich! Attorney, Agent, or Firm--Leo H. McCormick. J r ; William \ Antonis 1571 ABSTRACT A semi-metallic friction material for use in a vehicle hr.ike a< a `notion lining or pad The semi-meta!^ diction material utilm- the abrasive surface produced in coarse sponge iron to provide a high coefficient of triction and good wear resistance up to 250F to com phnu-nt the coefficient of friction and wear resistance ^.;pawe ot being produeeJ by the interaction of mctal- at... ceramic powders, stce! fibers, rubber particle-, md graphite ahove 25f' l 7 Claims. 2 Drawing Figures PMENEDa n o m < 3 ,8 3 5 .1 1 8 FIG. 2 3.835.118 1 2 SPONGE IRON FRICTION MATERIAL a high coefficient of friction upon initial engagement BACKGROUND OF THF INVENTION with a corresponding brake member These and other objects will become apparent from Friition materials consisting of graphite, metallic, ce reading this specification and viewing the drawings ramic and rubber powders held together by a thermo- ' setting resin have been used as brake pads in braking sv'ierr.' to provide a uniform coefficient of friction BRIEF DESCRIPTION OF THE DRAWINGS FIG 1 is a perspective view of a friction pad for use without excessive fade Such a brake lining material is fulls described in L S Pat No .'.4.14.998 incorporated in a brake assembly. FIG 2 is an enlarged view taken along line 2--2 of herein by reference 10 FIG 1 illustrating the relationship of the compositional The Department of Trunsportalion of the l S. Gov ingredients in the friction pad. ernment has proposed that acceptable safe braking dis tance' be reduced It has been determined that if an organu friction material, such as that disclosed in I S application Ser No .V>9.'.'!!. incorporated herein by reference, could be mtvdificd to piovidc a high civffi- DF:T AILED DESt RJPTION OF THE PREFERRED COMPOSITION Throughout this specification the terms metallic powder and ceramic powder arc used to denote a mate cient of frictian immediately upon engagement of the wear pads with a mating brake surface, the proposed standards could be met. Frictional modifiers havine' highci cocfTicicnt i'f friction were tried, however, un desirable side effects such as noise, poor wear. fade. grvHiving in the mating surfaces and reduced structural strength resulted SUMMARY OF THE IN\ ENTION rial having a nominal size which will pass through a No Ko mesh screen and consist of at least 85 percent of a base material with the balance being mainly oxides of ^*(1 the base material. Similarly the term "sponge iron" de notes a materia! having a nominal size. 85 percent of which will pass through a No 20 mesh screen, yet will be retained on an 80 mesh screen, and consul of at least 90 percent metallic iron 25 The brake pad 12 for a shoe 14 shown ir. FIG I is \\ c have discovered a composition for a scmimelallic friction materia! wherein coarse sponge iron constructed of a semi-mctallic material whose principal ingredients are sponge iron, graphite and modifie's particle' are utilized av a `oction.il modifier The abra- held together by a thermosetting phenolic resin which 'iv e surface of the sponge iron will provide a brake lin is then cured under heat and pressure to form a ing with a high coefficient of fnenon upon in ttiJ cn- blended rigid mass 16. as illustrated m FIG 2. While gagement with a co rrc'n o n Jin g b: .iking surface Be cause- the sponge iron p art-Jc - are unanncalcd .me, .a'se initaf burnish low vr.pvT cturc wcai 1on tin disc brake pud - are rot illustrate d. test result' indicate the same advantages car he found when this material ts u- ed on disc hMkcs Inctv'i: pad will be 'cdiK cJ The nregular surface ot ,s The sponge iron particles 18 are irregular in shape tin- course sponge :ro:-. wliich includes minute pm wrh a surface having pin hole void' therein The noics wh! compliment the noise attenuating com po sponge iron i' produced by a method known as the nent m the semi-metallic friction materia! to essentially Sicurin proces' Ir this process, powdered magnetite el m.nate seju-.-.d associated during a frictional engage- iron ore. c.irhor. eol.e and lime arc charged in layer' men' Since the sponge iron paMielO' have a nominal 40 into covercv! cruvibk-s These ingredients are heated in o re of between To to SO m c.h w huh tone' to rupture kil"' unui reduction is complete After cvK'hng. the under transverse loads, steel fibers in a proportioned iron produced which o removed will have a physical vl.-'-nnship with the sp-'iie-. io n r.irtiele' tire added to appeara-ice of a round porous cake abou- 10 inches in the s.-r.-'-PK-tallie friction material lo provide structural diameter and 2-2'*2 inches thick The reduced sponge an.ty for the brake lining -if cakes are then crushed and disintegrated into particle' It ;s. therefore, an ohieci of this invention to provide Hoeganac' Sponge Iron Corporation. Riverton. N.J .! 'e m met.ill.. base material with a friction modifier produce' sponge iron partielc' that are unannealed, consisting of coarse sponge iron particles to in v e a 'c di'ignatcd M 20/8'>. having a nominal size which can cold friction and reduce wej' when used as a brake vary from 20 mesh to ko mesh have proven satisfactory pad JO for brake pads These sponge iron particles have an It is another object of this invention to provide a abrasive surface sufficient to provide a high coefficient semi-mc-ialiic base m aterial for a brake pad having of friction upon initial engagement of the pad 12 with coarse sponge iron particle- as the principle compo a corresponding braking surface, yet are large enough nent to compliment noise reducing ingredients therein to resist abrasive wear at low operating temperatures, in attenuating sounds created upon the brake pad en- thereby reducing low temperature wear. gaging a corresponding brake member A typical composition for the scmi-metaJlic brake It is still a further object of this invention to provide pad 12 is as follows a semi-metallic material having coarse sponge iron par- tides uniformly distributed therein to provide a high coefficient of friction at low temperatures and steel fi \ olume Percent Volume Percent bers therein to provide structural unity when the serni- metallic material is used as a brake pad It is still a further object of thi' invention to prvvduce j senu-nietallic friction material consisting of a mixture ^ of metallic and ceramic powders, coarse sponge iron. ' graphite, rubber particle-- and steel fibers rigidly posi tioned in .i resin matrix foi use in a brake pad h.ving Metallic (copper Ir*** \ /. Sponge Iron PjmicIc* ( eromc Pu*derx mII'ht.jn rr rmilli?. magnesium i*\ide *.rrjfv mi^.ii aluminum .**, - %. vn \j. mm -xidr Sled f iSrr RhMv p-t'i ipl ; (1 ir ' 0 2* 1C U 4` : i is <> : :< J u . 'a |W '9 3,835,1 18 3 4 Phenolic retm hinder -Continued Volume Percent 23 Volume Percent 13 to 41 metallics (compared to organics) when operating at temperatures below 325T. Average driving seldom re sults in temperatures above 325T and is generally con sidered to generate brake temperatures of around 5 250T. Thus, the wear rate of any potentially commer cial friction material must be equivalent to organic ma terials at these lower operating temperatures The use The ingredients are mixed together and formed into of coarse sponge iron panicles has shown a significant a desired shape Then the mixture is placed in an oven reduction in both the 250*F and 325*F wear levels, where the resin is cured to hold the other ingredients 10 thereby improving the chances for commercial accep in a fixed position with respect to each other. After cur tance ing the resin the material is shaped into a finished prod As previously discussed, the proposed Department of uct such as the brake pad 12. The relationship of the Transportation reduction in acceptable safe brake various ingredients are illustrated in FIG 2 as follows, stopping distances requires that the brake systems re sponge iron particles 18. graphite particles 20. rubber 15 main balanced throughout the test. This requires a fric particles 22, ceramic powders 24, steel fibers 26, iron tion materia) which will exhibit the same friction levels powder 28 and resin 30. throughout the test. While conventional semi-metallic Brake pads manufactured according to a formula as materials exhibit better friction stability than most or represented above were compared with brake pads of ganics throughout the test, one problem was found with a conventional semi-metallic friction composition 20 conventional semi-melallic materials, that was low ini wherein the metallic powder constituted about 2001 by tial (pre-burnished) friction As a result, conventional volume of the total mixture with the following results semi-mctallic materials were unable to meet the pre- M^'v .. r St K- V :n. Ms Sc'*:- Ms I.:'*-v Spv'nj.'i Iron C o efficient of Frictio n 0 14 0 3' v i: i tv U 16 0 K <i i : Nfce.*r fin > 10 1 ' lo r 1K> S lo p * 10 k 5s o f < 10 10 Thi. importance of providing an initially high cocffi- burmshed stopping distances proposed by the Depart cierr for the brake pads can readily be realized from ment of 1 ransportation The use of coarse sponge iron the tom'* ing formula through which the effective brak xy particles in semi-metallics have demonstrated signifi ing distance on a level roodwav may be approximated cant improvement in initial (pre-bumished) friction, d = 1r>.30/ which will be required if semi-metallic materials are to be considered for commercial usage where r. - braking distance in feel 1 = initial speed, miles per hour Further, upon investigating the semi-metallic mate 40 rial. it was determined that the sponge iror. will compli ment the rubber particles therein to attenuate noise or ; = coefficient of friction between friction members squeal caused upon engagement of the brake pad with such as brake pad and drum a corresponding member. Assuming that the coefficient of friction will remain It is assumed that the voids in the sponge iron parti substantial!) uniform the period of time required to 45 cles act as acoustical absorbers by breaking up the path bring a vehicle to a stop will be proportional/) reduced through which sounds may travel. The over-all transverse structural unit) of the brake As an example, assume identical vehicles wherein pads mav be varied by the amount of steel fiber 26 used one has brake pads constructed of a standard semi in the mixture However, due to the disparit) in price metallic material and the other of a semi-metallic mate 50 between steel fiber and sponge iron (about 6 times). for rial with sponge iron particles and both are traveling at mass production a volumetric change in steel fiber con 60 miles per hour, the effective braking distance will be tent will usuallv be adjusted by a proportional change as follows in the quantity of sponge iron panicles d =60~*/(30 x 0.32) = 3600/9.6 - 375' Thus, we have developed a semi-metallic composi 55 tion wherein the structural characteristics are en d/sponge iron = 60~*/( 30 X0.38) * 3600/11.4 306' hanced by the use of sponge iron particles when used Thus the vehicle with the brake pads having a semi as a friction pad in a braking system. metallic material with sponge iron particles therein ex We claim choibniftosrma sthootrhteer perfofpecotsievde sbtorapkpiinngg ddiissttaannccee wofhtihche Dwiell 60 bra1k. eAassema if-rmicetitoanlliclinbiansge, smaiadtemriaaltefroiar lucseonisnisatinvgehoicflea partment of Transportation mixture of. The wear resistance of conventional semi-metallics metallic powder selected from a group consisting of are equivalent to organic materials between 350* and iron, copper, zinc and mixtures thereof from 0 to 450F and are superior to organics at temperatures 65 above 450*F However, one of the major obstacles to 30 percent of the total mixture; sponge iron particles from 10 to 40 percent by vol the accpetance of semi-metallics as a friction material ume of the total mixture, said particles having a has been the poorer wear resistance of the semi- nominal size which can vary from 20 to 80 mesh. 3,835,118 5 6 ceramic powders selected from a group consisting of claim 2, wherein said sponge iron particles, ceramic sillimanite. mullite. magnesium oxide, barium sul powder, metallic powders, and steel fibers combine to fate, aluminum oxide, silica, iron oxide and zirco provide said friction lining with a coefficient of friction nium oxide from 2 to 15 percent by volume of the between 0.34 to 0 45 in a temperature range up to total mixture; 5 250*F. rubber particles from 0 to 10 percent by volume of 4. The semi-metallic base materials, as recited in the total mixture. steel fibers from 0 to 20 percent by volume of the total mixture. graphite particles from 19 to 39 percent by volume of the total mixture, said graphite particles absorb ing thermal energy created during engagement of said friction lining with a corresponding member, and claim 1, wherein said steel fibers constitute between 3 to 16 percent by volume of the total mixture to provide structural unity for the friction lining. 10 5. The semi-metallic base material, as recited in claim 4, wherein said sponge iron particles uniformly distributed throughout the total mixture are unan nealed to provide reduced low temperature wear rates a phenolic resin binder from 13 to 41 percent by vol ume of the total mixture, said phenolic resin binder being responsive to heat to form a solid matrix for holding the selected metallic powders, sponge iron particles, ceramic powders, rubber particles and steel fibers in a fixed relationship 2. The semi-metallic base material, as recited in claim I, wherein said sponge iron particles and rubber 1' 6. The semi-metallic base material, as recited in claim 5, wherein said sponge iron particles uniformly distributed throughout the total mixture are to provide increased friction in the prebumished slate. 2q 7. The semi-metallic base material, as recited in claim 6, wherein said sponge iron particles uniformly distributed throughout the total mixture are to provide particles attenuate any noise created during said en less frictional change from prebumished, to burnished, gagement to faded state 3. The semi-metallic base material, as recited in ;x ***** 10 IX 40 45 SO 55 60 65 m'- n.n. . *.tc' rrk`>:ivi r-T t.' :v"' U'iv.ntU''- 'u.-'. - -'-.f/ur.i ;,n- , -, r$i\'- . V icia n .KvH-7 CSTCUj-ixl - i > 0 fters c/ Bpuz> r-- -cnTfct^. *r\k> r.i>;p^ - ,t "':'X Iv r '.'J.i.' s.U'<- 7 u u r^Cloru ?rMw - cf gtao* rft&rk -tciw; .- ,1'ftct4cio.iul7 (i"- *J" TvU 7 lo r. frk tta a .textor k -.k -v\J : *\>;"..GXwrrk ' M o -nkU< V-, cSfcLpr'im:-*! r-u". ' V*t>r ':o~''vc 'V-.TU, !K *>r, Y* Mi ' fi July 19, 1960 F ; . ed Ndv 26. 1956 T G A N K EN Y ET AL " R IC 7 IC S M ATERIAL 2,945,291 2 Sheets-Sheet : 9 July 19. 1960 r i l ' d Not. 29, 1966 T G ANKENY ETAL FRICTION MATERIAL 2,945,291 2 Sbt-SbM t 2 9 J S f . f INVESTOk. fa p s& a c S tfJ v s r y j t t Lru?st* 3 c r attorney United States Patent Office Patented July 19, 1960 1 2,945,291 FRICTION At. MATERIAL Thomas G. Ankeny. Birmingham. Mich., and John W. Arnett, Dayton, Ohio, m ig o o n lo General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed Nov. 28, 1958, Ser. No. 776,973 8 Claims. (Cl. 29-- 182.5) This invention relates to friction materials and is par ticularly concerned with ferrous friction members for use as clutches, brakes and the like This application is a continuation-in-part of applica tion S N 5 4 0 4 2 . filed October 17, I55. now abandoned An object of the invention is to provide a ferrous fric tion facing consisting essentially of iron, graphite and molybdenum disulfide In carrying out the above object, it is a further object of the invention to form the friction member from a intered m-'\luic consisting e"ontull> of iron powder, graphite and molybdenum disulfide wherein the graphite makes up between one-fifth 'n d one fourth of the weight of the member A still firthcr object of the invention is to provide a ferrous fpcoon member where-n the member consists essentially of graph:'.,- i.i r e n c between 20'. and 25ri b' weigh: mobKlcnum doulfide between 2 ^ and 6 ^ bv weight with ton making up substantially .I' the re mainder Another object o? th. invention to provide the frr- roto friction dement a- heretofore disclosed wherein the element is coextc' .'d v bonded to a strong metal sup porting memhci tor facilitating mounting of the friction element More specific.'lv. it is an object of the invention to provide a sintered ferrous friction facing consisting essen tially of 20't graphite. molvbdenum disulfide with substantailly ,1! ;)ie icmainJcr being iron wiih or without small additions of modifying materials wherein said per centages are expies-cd on a weight basis Further obie.i- and advantages of the picsent invention will be apparen' f:om the following description reference being had to the acsompanying drawings wherein pre ferred embodiments of the present invention are clearly shown In the drawings Figure 1 is a view ;n perspective of a typical brake band Figure 2 is a view in perspective of a clutch disc Figure ? is a view in perspective of a clinch or brake disc for use in a clinch or brake ra d . Figures 4 and 5 are charts showing a comparison be tween convention. ! and metallic brake linings in de celeration testy Modern automotive developments have imposed ex treme operating conditions on the conventional type of clutches and ta'akcs The friction surfaces of conventional clutches and brakes arc usually composed of molded non metallic material such as asbestos, cotton linters and the like bonded together with a synthetic resin such as a phenol-formaldehyde resin, the mixture may also include friction fortifying material' This mixture of ingredients is molded into a brake band or disc surface which may be bonded or riveted to a metal support. While these fric tion elements and facings are satisfactory under normal driving conditions, it has been found that repeated stops from high speeds causes a tremendous overheating and 2 eventual breakdown of the materi ils used in the brakes In most cases, nonmetallic brake materials are not use ful at temperatures above 750 F. and such temperatures are frequently exceeded in repeated high speed stops under 5 extreme conditions Since the trenJ in automotive design is tov ml heavier and or higher poweied vehicles, it is apparent that the friction malcr.als ii'cj in the brake and dutch surfaces must be improved in order to keep up with ihc develop 20 ment of the industry It has been found that metallic Inetion materials offer an interesting fic'ld of development Flow ever, most metallic friction materials while highly satisfactory, for example, in wet clutch applications are not useful for ir> brakes since they tend to s.|tieak and grab in the dry condition Furthermore, due to the abr..sion of the mate rials in the dry condition, much of the friction facing is abraded from the friction ' ii r ij .c whu.h. in turn, sclf- . gruav ales the wear condition I a: :!u ! mo; e. ihc noisi 20 ness of lhese materials has made the.n unsuitable in the past for passenger vehicles There arc. however, man. aJv a tra 'tcs in :he use of metallic inetion materials, some ol tin mote important being ability to withstand hieh t. tiper.:ti;i. conJuions, 20 abditv to withstand hi..'her eng., un-.- pi. -ares and. in most cases, longer wearing char.ivtenstus We have developed a fn.t-on material vvh.,h overcomes these past disadvantage of me: li.c fr;. 'n materials when used in the dry stale and winch h..s maintained 30 all of the . Jvantage-. of mela'I-c fa.tig materials We h.ve found that our friction mu:-.ru1 v l-.c t -. I m con junction with a di-c or band op e b'ake. will outlast nonmct.i'.lic fncuon mateti.i1' min;. .me*. and will not be dvi.-teriouvly affected .u ill. hi. I :. n i p . r e a c h e d .30 during repeated high speed stop- In t w . - u tests show that the pres.nt f:jetton m./.t-.d ' I! oj:-ve..r several vis of conventional nonm.:.illi. tr . i on -i mat .rial under identical operating condition- Futth.: i-.-e the metallic friction material doc- not exhibit th. fade-out of frictional 40 quahties normally present in non teial'i. niat.ri.il when excessive temperatures arc encountered Under actual road conditions, the present friction mat- n.d operates smoothly and silently throughout cv.cn led u-e In fact the facing material operated well undei , .uprising 46 ten consecutive stops front a maximum -peed of one hundred miles per hour, a eond.uon wh-.h on,hi not he duplicated with nonmei.illie .tines which ruled com pletely after three to four of such stop- Our new friction mateti.i! i- a sinter, J ferron material 80 having vaijy ing degrees ot poro-in and m.iJe from a mix- tuie consisting iss.nlialU of non po.-iUr er.,phne and molybdenum disulfide to tta- b.,si.- i.-,i\oae in.n be added small quanting' ol siilt.ir and , e n n v . materials such as .aleine'd mulhtc loge'hei wish coprvi and lead 66 foi modifying the action ot ihc In.i.on material The friction maienal i- pref.-iahiy bon.l.d r> stron-.' metal support through which it n m be suitablv -.-.uie to the brake or dutch median,-m m wh,.h it is to be subse quently used D,,e to th. ,n . .,-n,c .1 .. I.og. quantity of 0 gr.,phite. the nta'eri.d doc- n-u hav. a hrch decree of flexibility and i- not rc.ul.-iy bend.ible and. ihcrefoie. the strong metal support such as a steel backing is generally preferred. Specifically, ibe m Uii 1coni.un- gi. oluic' in quantities 06 of from 2 u \ 25 . b> wcighi together with molybdenam disulfide in qu intitic ot tn-ni 2'. to 6 ' i by weight with substantially .dl the tent under being iron The material is m ide by nuving the ingiedients in finely divided form wherein, foi example, ihc non powder ranges 70 between I5u and 325 mesh I his inixiiue i then briquetted to the desired sh. pc unJer briquetting pres sures ranging from 40,0:) lo lull,mu) po..nds per square 3 inch, preferably 1 70.00U pound per square inch The briquettes art next sintered for about 45 minutca at a tem perature ranging between 1650* F. and 2050* F. under e e m a lu m condtuoo*. (or example, 11 debydramU, moompiesaly burned natural gee, cracked ammonia 01 hydro- m. The raeuhing materia] present* a highly desirable friction material that will withstand high temperature*. -- u frictional qualities over a wide range of lam- parKarri a te which it long wearing end quiet In I " caaet, a* previously stated, it h desirable to bond tte mqperial to a strong backing member, and tint is accomplished by placing the briquettes upon supporting memlTKt of Heel that have preferably been lash-coated with copper A number of these "sandwich**" art stacked on top of one another with suitable spacers therebetween m i the bonding is accomplished with the Hack under pita- ame. A procedure of this character is fully dacloted in Wellman Patent 2.178.527 and is well known in the art. It is preferable to accomplish the sintering and bonding in a single operation although it is also possible to first sinter and then bond It this case, the briquettes are sintered between sheets of graphitic material or metal having a nonadhenng refractory coating thereover. Another modification of the process contemplates a presuuer of the briquetted powder at a temperature in the order of 1600' F to 1950' F for a period of 30 m 45 minutes This partially sinters the briquette end makes it easier to handle. The preaintered briquette is than assembled with the backing member and is bonded in the usual nunne: at about 1750' F. for 30 minutes. Them conditions may vary, for example, the bonding tem perature may be between P 5 0 ` F and 2100* F while Lie ilma may be between 20 minutes and 45 minutes varying inversely as the temperature During the bonding step, the porous pan is completely sintered. These variations in operating conditions may vary widely and are not critical so long as a good sinter and bond is obtained A preferred embodiment of the invention comprise* the following formulation. Example 1 22% Acheson 38 graphite 4% molybdenum disulfide, 100 mesh 74% 250 mesh reduced oxide iron powder A mixture of this material is bnquetted at 80,000 pounds per square inch and is sintered on a steel support ing member of the desired configuration which has a flash copper plate thereon for a penod of about 45 minute* at 2050* F under pressure whereupon the material forms a strong sintered ltyer coextensively bonded to the sup porting membe: The friction and wear characteristics of this material may be modified by small additions of sulfur and ceramic materials such a* mullite, days, etc. In this case, the sulfur is preferably combined with the iron or may be an impurity therein and may range up to 1% by weight of the total mix This sddition ap pears to improve wear The ceramic material, such as muiliu, may range up to 75% by weight of the total mix This addition act* as a friction modifying material and generally raise* the coefficient of friction slightly. In any case, these additions are optional and should not eacete a total of 2% by weight of the element. It is understood that, in many case*, the effects of sulfur and ceramic* can be attained without adding any material to the mix. In these cates, reduced oxide ires powder may be chosen which contains sulfur and insoluble ceramic material within the ranges noted as impurities thereui Similarly small tdditions of lead and'or copper may be added to modify friction characteristics as is welt known in the art For example, copper up to 5% by wmghi and or lead up to 5% by weight may be added Them modifications prove useful under certain conditions. Our icvsuijoc, however, is directed (pacifically to the basic formulation of a high percentage of graphite (20% 4 to 25% ) with molybdenum disulfide in controlled amounts wherein the remainder of the element consists essentially of iron with or without the modifying ingredients set forth berem. 6 Some specific examples of other mixes which are satis factory are as follows wherein all percentage* are ex pressed by weight Example 2 10 20% Acheson graphite 3% 150 mesh copper powder 5% 100 mesh lead powder 5% 100 mesh molybdenum disulfide .75% calcined mullite 15 66 25% 100 mesh reduced iron oxide powder containing combined sulfur therein equal to I % of the iron This mixture of powdered materials a briquetted at 70,000 pounds per square inch and may be sintered on a steel supporting member which has been flash-copper 20 plated for a period of forty-five minutes at a temperature of 2050* F. in a nonouJjzing atmosphere under pressure The powdered matenal forms a strong, sintered layer coextensively bonded to the supporting layer. Example 3 22% Acheson graphite 4% 100 mesh molybdenum disulfide 74% 250 mesh reduced iron oxide powder containing in combined form sulfur together with insoluble ceramic 30 matenal in quantities equal to about 1% and .75% re spectively of the total mix The mixture of these powdered matenals may be prepared and sintered as in Example 2 35 Example 4 20% Acheson graphite 2 5% 200 mesh copper powder 4.5% 100 mesh lead powder 4% 100 mesh molybdenum disulfide 40 .75% sulfur .65% calcined mullite Remainder 100 mesh reduced iron oxide powder The same procedure for forming the materia! and sintering 4g the " as in Example 2 may be followed Example 3 21% Acheson graphite 4% 100 mesh lead powder 50 5% 100 mesh molybdenum disulfide Remainder 250 mesh reduced iron oxide powder con taining cQmbined sulfur equal to about 1% of the total mix. A mixture of this material may be formed and sintered 68 as in Example 2. In the drawing, several forms of the friction member gaarrihtirl in this disclosure are shown For example in Figure 1. a conventional type of brake band 20 it shown which has a ferrous friction surface 22 and a metal 80 1opporting back 24. This band may be made as herein described by placing preformed friction layers 22 upon the preformed supporting members 24 and stacking the sandwiches under pressure in a suitable furnace for steering. Figure 2 shows one type of clutch plate at 26 ns which includes a tplined hub 26, a steel disc 96 and friction surfaces 92 bonded thereto The friction surface 92 may he provided at both sides of the dutch (as shoum) if desired _ Figure 3 shows still another form of clutch or brake * at 94 In this form, the steel disc 94 supports a friction smfaoe 96 at one or both sides thereof and the disc may be tplined as at 46 on the outer periphery or as at 42 at the inner periphery thereof This type of plate is gen rally uaed in a pack wherein alternate plate* are sptined at the inner and outer periphery respectively These 5 pinte* may be used in dite brake*, for example, ai dis 6 While the forms of embodiment of the present in cJonnd in Lambert Patent 2,405,219 which *bow* one vention as herein disclosed constitute preferred forms, type of automotive dite bra' e. or multiple plate clutche* it is to be understood that other forms might be adopted. at ditcloMd in Almen and Carnegie application S.N. What is claimed it as follows' 392,596, now Palest 2,733.597. u>i|Tit^ to the assignee r> I A new article of manufacture, comprising, a fnc of the preaent invention tion facing consisting essentially of a compacted and The three curvet in Figure 4 thou contecutive ttop* sintered body formed from a powdered mixture of 20ft at one minute interval! at 50. 60 and 70 miles per hour to 25ft graphite. 2ft to 6 ft molybdenum disulfide and with a commercial molded nonmetallic lining wherein the balance iron. tbe rate of deceleration it maintained at fifteen feet per )0 2. A new article of manufacture, comprising, a fric second per second. The "fade" characteristics of the tion facing consisting essentially of a compacted and lining are indicated by the increasing hydraulic pressures aintered body formed from a powdered mixture of 22ft required to maintain constant deceleration Thus, at graphite. 4ft molybdenum disulfide and tbe balance 50 mile* per hour, the pressure required to maintain this iron deceleration varied from 490 pounds per square inch for ).' 3. The article as claimed in claim 1 wherein the friction the first ttop to 855 pounds per square inch for the tenth facing is coextensively bonded to a metal backing mem stop At 60 miles per hour, these figures were 560 ber ' pounds per square inch for tbe first stop and 1145 pounds 4. The article as claimed in claim 2 wherein the friction per square inch for the tenth At 70 miles per hour, facing is coextensively bonded to a metal backing mem- the lining failed on the sixth stop tin ber. By way of comparison. Figure 5 shows the same curves 5. A new article of manufacture, comprising, a fric for our improved metallic lining as described herein and tion facing consisting essentially of a compacted and made in accordance with Example I It will be seen sintered body formed from a powdered mixture of 20ft that tbe pressures required for the first stop are con to 25ft graphite. 2ft to 6ft molybdenum disulfide, and sistently lower and that the pressures required for subse 2.' the balance iron wherein the iron includes as impurities quent stops are substantially constant No failures were insoluble ceramic maierial up to ,75ft and sulfur up to noted All tests were made on identical equipment and 1ft by weight of the powdered mixture with identical braking elements with the exception of the 6. The article claimed in claim 5 including lead and brake material per se In this instance, the commercial copper in quantities less than 5ft by weight each lining tested was of a 40 8 square inch area while the 3u 7. A new article of manufacture, comprising, a frK- ferrous lining was only 36 square inches in area tion facing consisting of a sintered compact of graphite The present invention, therefore, is directed basically 20ft to 25ft , molybdenum disulfide 2ft to 6ft . sulfur to a porous ferrous friction element including a relatively up to I f t, mullite up to 7 5 ft. copper up to J f t . lead high percentage of graphite together with significant quan- up to 5ft and the balance iron, said quantities being ex- uues of molybdenum disulfide wherein said element may 3-"> pressed by weight or may not contain small addi'ions of wear and friction 6 A new article of manufacture, comprising, a fric modifying ingredients The friction element may also tion facing consisting of a sintered compact of graph,:e include an imprgnant within the pores thereof if it is 2 0 ft, copper 3 ft, lead 5 ft, molybdenum disulfide 5 ft, desired for sealing the pores against the ingress of the calcined mullue ,75ft, sulfur 6 'f t and the balance atmosphere where the material is to be stored over ap 4>J iron, said quantities being expressed by weight preciabie periods of time. This material is preferably a beat resistant resin which can be impregnated into the References Cited in the file of this patent material and which does not markedly influence the ufrnicdteiorsntaolodchathraactteurinsptircesgnoafntthse mmaaytenbael useTdhewreitfhooreu,t itdeis 45 parting from the concept of the invention Throughout this specification, the term ceramic material it used together with mullue as one embodiment there of. It is to be understood that this example is illustrative 50 only and that clays, silica magnesium oxide, mica or 2.239.134 2.367,406 2.408.430 2,731.360 2.784,105 2,848,795 UNITED STATES PATENTS W ellm an................................Apr Kott _________________ Jan Lowey et al ___________ Oct Love .............. .................. Jan Stedman et al. ________ Mar L o w ey _________________ Aug 22. 1941 16, 1945 I, 1946 17, 1956 5. 1956 26 1956 any of the other refractory ceramic materials may be used with varying useful results. July 19, 1960 Pl 1*4 Nor. 98. 1888 W. A. LUTHER. JR., ET AL FRICTION MATERIAL. 2 ,9 4 5 ,2 9 2 2 Shft8- S h M t 1 * ru tir Attorruy m mm m 6utiM *ex p uoi oy M P V iOi||iM SVOli&ANI Coefficient of Friction Time In Minutes Fig. 3 ^ )im H tu i|S 8 Temp, of Broke Drum eeet > *n p*tt4 United States Patent Office 2,945,292 P n tn n t.d Ju ly 1. IM O 1 metallic lubricant melts and exude* to (be surface of the element during use to stabilize the frictiooal char IM M W acteristics of the dement. Further objects and advantage* of the praaent inven FIKTION MATDtUL e tion will be apparent from the following dcacription, ref V O a i A. U A , Jr-, m i Wotond F. Koehring, Di j - e r " " * being had to the accompanying drawings wherein M , Ohi*, a i p M i I Cenemi Motori Corporation, ritolti M Uk, I corporation t i Dolnwnre preferred embodiments of the present invention are d ear ly shown. In the drawings: F M Nor. U , 195, 1er. No. T 7 7 I 10 Figure 1 is a perspective view of a typical brake band H C U M . (C t 19--t l l S ) including the ferrous friction element thereon. Figure 2 is a view in perspective of a conventional clutch disc utilizing the ferrous friction facing thereon. Figure 3 is a chart of a family of curves for ferrous T ka invention relates to friction materials tod n per- 15 friction materials including different metal lubricants aad -- concerned with ferrous friction member* for showing coefficient of friction plotted against time and me m d u tch , brakes tnd the like temperature. Ttos ippbceiioe u t continutuon-in-ptn of applica Figure 4 is a perspective view similar to Figure 1 t e &N. 6*4.954. tied September 19. 19S7. bow aban showing another means of attaching the friction lining doned 20 to the shoe An object of the invention * to provide a ferrous fric Figure 5 is a view of one segment of the friction ma tion facing conuttmg essentially of iron, graphite and a terial and its support metallic lubr. -nt consisting of bismuth or alloys of bis- In modern automotive development, extreme operat t h with omuls that are substantially insoluble in iron ing conditions are encountered at friction surfaces used In carrying out the above object, it is a further ob 25 for b.akes, clutches and the like. These extreme condi ject t i the nrvnrtoion to form the fricuon member from tions make conventional nonmeullic clutch facings and a sintered mixture of iron powder with graphite which brake linings costly to use since these materials must op member also contains a lubricant metal in the form of erate below certain limiting temperatures if tbeir eft lboiysms uatnhd, bwishmeruetihn-le<a"daphalnleoysm, akanesd ubpismausthu-bcsatdanmtiiaulmpoarl 30 cainedncoythiesr todebveicemsationtaliimneitd thwehitcehmpreeqrautiureresscooIltinigs, mtheedriea tion at the member fore. desirable to provide facing materials for clinches, A still further object of the invention is to provide a brakes and tbe like which can withstand considerably ferrous friction member which consists essentially of higher temperatures than the usual nonmeullic materials agralpuhbirtiecartianngginmgetbael twsuecehn 2as 0bisamnudth30'o~r< bbiysmwuethighatllaonyds 35 aacntderwistbicusb tmhraoiungtahionustubthsetairntioaplleyractionngsttaenmt pferircattiuornealracnhgaer wherein the alloy has a melting point no: greater than the Metallic facing material* made from tmterad metals melung point of bismuth and wherein the oihc: metals such a> sintered bronze sintered iron and the like have in (he alloy are substantially insoluble in iron been used sparing,y in the past and while the wear char- In carrying out the above object it is a further ob 40 dcteusncs od these elements are considerably belter than ject where bismuth or a bismuth-lead alloy is used as a nonmetallic elements, it has been found difficult to con lubricating metal, to include small quant.tics of an add. trol the coefficients of friction thereof through the wide tiona! metal substantially nonalloy able with the lutncat range of temperatures that are encountered in normal mg metal, one of such meuls being coppe: operation whereby the build-up in friction during suc It is a further object in some cases to utilize small cessive slop* makes them erratic in their operation and. quantities o ' sulfur not over If* in combination with 45 therefore, generally undesirable the iron either as an added ingredient or as an impurity Recently, improved friction facings have been pro m Am iron used attd or a ceramic matenal such as mill posed of the meullic type wherein substantial quantities ifte in quantities of less than I? of gidphite have been incorporated therein to smooth Another object of the invention is to provide the fer out the coefficient of friction to some extent over a wide tout fnctioB element as heretofore disclosed with a strong 60 range of temperature These facings provide consider metal upportmg member for facilitating the mounting ably better operating characteristics and are frequently of the friction element, said member taking the form entirely satisfactory under normal operating conditions f a sintered farrows matenal of different composnion However, when heavy duty service is encountered such aenodrttgevteaaisveerfystrthenegrethtothan the friction element and bonded 66 asps.eefdosr, etxhaemseplfencwuiotho umxaictearbias.lsbudsosensoot r asltwoapyssfrmomainhtaiginh More specifically. it is an object of the invention to their stability within the range desired providt a sintered ferrous friction element consisting The present invention is directed to a friction matenal cjoentiaHy of graphite 30 to 45 parts by weight, copper which has a stabilized coefficient of friction and, there t0hetroeof156 ptaortsIS bpyarwtseibgyht,webiigshmt uathnd oirroinnso1l0u0blpeanasllobyys 60 cfoluretc, hisorexbtrraekmeelwyheurseeinfulstainbilaizneyd afpripcltiicoantiochnarsaucctehrisattic*a weight are desired over a wide range of temperatures, whether in carrying out the above object, it is a further object or not the application falls in the category of a heavy to optionally indode sulfur and mullite in rhe above duty application We believe that this stabilization of forAmnuolathtieorn.object of the invention is to provide a fer 66 ofrficatiomn ectahlalircacltuerbirsitcicasnt iswahcicchomisplitsrahnesditothryrouinghchthareacuteser rous friction member containing substantial quantities of at the surface of the element, that is to say, tbe lubri graphite together whh a lubricating metal which is sub cating metal is held in Ihe solid state within the pores of stantially insoluble in the metals making up fhe ferrous the friction element at temperatures below its melting friction member, said lubricating metal having a melting 70 point and. when these temperatures are exceeded, this point within the range of temperatures encountered Jur- metal, due to its insolubility with the other components feig subeeqnent use of the friction element whereby the of the element and doe to its expnnrion, wilt exude onto the surface Si the element end provide a fluid lubricant which stabilizes the frictional characterisucs of the tie meat while maintaining the detired frictional characteiittid thereof at provided by other component! of the ele imerface between the element and the brake drum or other nibbing surface, etc. Some examples of suitable mixtures are at follows, all proportions being in pant by weight: ment It is understood that, in the description to follow, the ferrow* friction element may be used in connection With brake bands or clutch discs or brake discs as the caae may be For example, in Figure 1. a conventional brake band is shown at 2 t which includes a plurality of pads of friction materia) 22 attached thereto In Figure 2. a dutch disc or brake disc is shown at 39 which includes a steel disc 32 having t friction layer 34 attached thereto _______________ -- - - - - gpoogt or Kidured Oxi-lt- Iron (with or ifftout r*" n- ................... ::::: Mullite. ..................................... E i 1 e ,: l-rt 46 A .7 Kk 3 i:. -- 100 |Or 10 46 6 9 4 .76 E i 6 E i ft -- -- too too u 60 10 16 11 6 Specifically, we have found that, in a ferrous friction element wherein tbe mayor component is iron, large quan 15 These ingredients in finely divided form, for example, title of graphite are highly desirable to supply the de capable of passing through a 100 mesh screen arc inti mately mixed and are briquetted into the detired shape sired frictional characteristics to the element In this connection, graphite ranging from 209c to 309c by weight under briquetting pressures ranging from 60,000 to of the element is incorporated in tbe element together 20 8u0n,d0e0r0 npoonuonxdidsizpinegr csoqnudairteioninschforanfdromare30theton 4s0intmeriend with a lubricating metal such as bismuth, or alloys of bismuth with metals which are insoluble in iton and utes at temperatuers ranging from 1800* F. to 2000* F. wherein the melting point of the alloy docs not exceed In each case, a sititered friction element is formed which the melting point of bismuth, for example, lead-bismuth will exude bismuth, bismuth-lead, e tc , as the case may alloys and cadmium-bismuth alloys The low melting be, at the surface thereof metal may be bismuth alone which melts at about 520 F 26 More specific examples comprise or it may be an alloy of bismuth and lead which melts Example 7 at or below the melting point of bismuth In this con nection. an alloy of 88rr lead and 129V bismuth h j' 67 parts --250 mesb sponge iron powder (combined sul fur up to 1% by weight) substantially the same melting point of bismuth where..s 30 20 pans artificial graphite (density 1.85 grams per cc., the eutectic alloy of lead and bismuth which contains --325 mesh) 55'-'i bismuth and 4 4 'i lr-. 1 melt, at about 25.'' F Thus, bismutb-lead alloys where the minimum bismuth 8 parts 150 mesh copper powder 5 parts 100 mesh bismuth powder percentage is 12f"< may be used ,'s a substitute for pure bismuth according to use Mnce un\ alios having this These ingredients are intimately mixed and are briquetted composiuon will meli at or below the melting poim ot 33 at 60 00O pounds per square inch and are then sintered bismuth In this connection the service requirements of for 40 minutes in a nonoxidrzing atmosphere at 1800* F the brake should be taken into consideration Heavy The resulting friction facing has a fiber strength in the duty applications are best seived by the higher melfng order of 3720 pounds per square inch point alloys whereas light duty applications may make use of the lower melting pom; alloys In .'ll vases it Example S is desirable lhai the melting point of the lubricating 67 parts --250 mesh sponge iron powder (with 1% com metal is in the range of temperature attained durutg nor bined sulfur) mal use of the friction element uod ihvse Cuiid.i.uii-, 15 parts powdered artificial graphite (density 1.85 grams therefore govern to a large degree the choice of material per cc., --325 mesh) Similarly, alloys of bismuth and other metals mu> he 45 15 parts coarse flake natural graphite (density about 2 1 used wherein the other metal in the alloy is substan grams per cc., 2o to 30 mesh) tially insoluble in iron for example, cadmium is in 5 parts 150 mesh copper powder soluble in iron and alloys with b.smuth to form low melt 10 parts 100 mesh bismuth-lead (50-50 mixture) with ing point alloys In thi- connevtion. an alloy of 2597 50 or without \ i pan 60 mesh synthetic mullite bismuth and ~5''f cadmium has substantially the Same melting point of pure bismuth whereas the eutectic alloy These ingredients are intimately mixed and briquetted of 60r< bismuth and 4n'7 cadmium melts at about at 70,000 pounds per square inch and sintered for about 292' F Stated broadly therefore, alloys of bismuth with 40 minutes in a nonoxidizing atmosphere at a tempera metals insoluble in iron wherein the alloy has a melting ture of about 1800 F. The resulting friction element point not in excess of tbe melting point of b.smuth are 65 has a fiber strength in the order of 3045 pounds per useful as the lubricating metal square inch. Thus, it will be seen lha; we hove chosen a lubi b at It is understood that the lubricating metal such as ing metal which is insoluble in the iron and which melts bismuth-lead alloy may be introduced by impregnation within a range of temperature generally reached bv the if desired, although tbe usual technique as described here friction element during use Otiicr msoulble metals could 60 tofore are preferred Furthermore, due to tbe sintering possibly be used but, in these cases, the melting point is step, it is usually not necessary to pre-alloy the bismuth sufficiently high that the liquidus state of the metal is with any other metal to be used therewith since alloying w'ill occur in situ during tbe sintering. not reached upon operation of the friction element All of the above friction elements made by any of whereby erratic results occur due to the fact that the 65 tbe aforementioned examples are preferably bonded to a to-called lubricating metal may be liquid in one case more dense and stronger material during the sintering and olid in anothei to enable them to be riveted or spot-welded to 4 steel Therefore, in each instance, the low melting point shoe or plate. This particular step forms no part Of the metal, which acts as a lubricating metal, melts at tem present invention and is fully disclosed in copending peratures within the normal operating temperature range Smiley application, S.N $96,266. filed July 6, 2956, as of the fnction element and. in each instance, where com signed to the assignee of the present invention. Specifi binations of these low melting point metals are used, cally, a backing material that is particularly useful with the eutectic mixtures thereof meli at relatively lower tem the present formulations, since it has similar physical peratures to quickly stabilize the frictional character change characteristics during briquetting and sintering, istics of the element by presenting a liquid phase at the comprises a mixture of about 95 parts 100 mesb sponge 5 6 iron powder. 5 p u tt low drasity powdered graphite earn, h srifl be aotad (ha* fee co aM eot of frfeftea a t (1.61 ( ru m per cc.. --325 mesh), ta d three pen* of the Ksriag is euetaMc until the wmperatuie a t epervlioa as molybdenum rtiad phirl* powder (256 m e * ). Tbeee in- cend* the melting point of the habricaM Metal at wMah grWwnu u t iatiauuly a l u d and the mixture ia (low A t Beeflfcimt a t friction levels eff sad heeemei ia e die ia desired quantity. Any a t the aforemeatioaed 8 stehikaed friction onerrial a i m it then filled inso the die aad the two layer* are simultaneously briquetted at preeauree of frum 60,000 to 60,000 pounds per aqeart och. The briquette it tiaiered under condition*, time* and tem perature* noted in any of the examples A extensively Thenegbam * ia spacaficaiioa, the teem emamic merial is uaed lfsgwhw with aauHitt m a m aaabedims thereof, ta is to be nademtood that this o i e g l i ia il lustrative ooly and that clays, silica magnesium oxide, Il mica or any of the other refractory ceramic materials bonded material is formed havinf a strong backing layer may be used with varying useful results. and a friction facing of the desired characteristics As mcetiooed before, the application S N $96,266 gives a detailed disclosure of the method of making these com While the embodiments of the present invention at herein disclosed constitute preferred forms, it it to be understood that other forms might be adopted. posite friction elements and the present invention is di ls What it claimed is as follows: rected solely to the frictioo layer and its characteristics I. A friction material for use as a friction facing ele In place of the composite material described, the fric ment. consisting essentially of: a sintered ferrous base lion layer may be supported by and bonded to a retaining having dispersed therethrough graphite in quantities of device or member made of stamped or cast metal Such from 20% to 30% by weight, together with at least one a retainer is shown at 40 in Figures 4 and $ The re 20 metal taken from the class consisting of: bismuth, bis tainer 46 is preferably made of stamped steel and is muth-lead and bismuth-cadmium alloys wherein the made in the form of a shallow cup or tray which carries melting point of the alloys does not exceed the melting a friction material layer 41 therein The retainer 46 point of bismuth, said last-mentioned metal being pres may include fastening means 42 welded or otherwise at ent in quantities of from 3% to 10% by weight tached thereto as shown in the right side of Figure S or 25 2 A friction material for use as a friction facing ele the ret .er may be riveted by means of rivets 43 or di ment. consisting essentially of a sintered feirous bate rectly welded to the band 26 In the case of rivets 43 having dispersed therethrough graphite in quantities of being used, the friction layer 41 is counterbored so that from 20% to 30% by weight, together with bismuth in the heads of the rivets bear against the container In quantities of from 3% to 10% by weight a)) cases, the fnciion layer 41 is sintered and bonded in 30 3 A friction material for use as a friction facing ele situ to the container 40 by briquetting the powdered ma ment. consisting essentially of. a sintered ferrous base terial directly in the retainer Prior to the briquetting having dispersed therethrough graphite in quantities of operation, the retainer surface is preferaby flash copper from 20% to 30% by weight together with a bismuth- plated as well known in the art to facilitate the bond lead allov having a melting point noi exceeding the me't- It will be observed that, when the graphite content of 35 mg point of bismuth in quantities of from 3% io 10% the friction material exceeds 25%. different manu/aciur- by weight ing technique- are required in order to form an elerr.eM J A fnciion materia) for use as a friction facing ele having sufficient strength for the intended purpose and. ment consisting essentially of a sintered ferrous base to this end. different types of graphite are used to over having dispersed therethrough graph'te in quantities o ' come problems which arise when using either type of 40 from 20% to 30% by weight, together with a metal taken graphite alone These manufacturing technique; form no from the class of bismuth and bismuth alloys with metals pan of this insertion and are fully disclosed in copend insoluble in iron wherein said alloys have a melting point ing applicauon SN 684.853 (Docket No M P-27l2i. not in excess of the melting point of bismuth in quanti filed September 19, 1957, wherein the full disclosure of ties of from 3%- to 10% by weight the reasons for mixing the different types of graphite 45 5 A sintered fnciion material for use ns a frui or are set forth In this connection, so far as the finished facing element, consisting essentially of iron in.lud ng friction elemem is concerned, there is no substantial dif sulfur up to 1% hy weight thereof. 100 parts graphite 30 ference in the operational characteristics of the different to 45 parts, copper up to 15 pans, and a met-! mien types of graphite but the strength of the finished cle from the class consisting of bismuth and bismuth alloy ment it markedly enhanced by mixing two types of 00 with metals insoluble in iron wherein said alloys have graphite melting points not in excess of the melting point of bu While the friction elements utilizing graphite in the order of 20*2 have good frictional characteristics and muth. 6 to 10 parts, said proportions being expressed as pans by weight. under normal operating conditions function well, there 6 A sintered friction material for use as a fnciion it tome tendency toward noisy operation under certain U facing element, consisting essentially of: iron, including specific conditions As the graphite content is increased, sulfur up to 1% by weight thereof. ICO pan., graph.ic ibis noise condition decreases to a point where the ele 30 to 45 parts, copper up to 15 pant, mulliic up to i 'i ment is comparable with conventional nonmcullic ele by weight, and a meiul. taken from tbe clas. consisting ment. at 25% of giaphitc and above In other words, o f bismuili and Ifi.iu ih alloys with metal nsohible m at the graphite increases, the tendency toward noise de 641 iron wherein said alloys have melting points not in ex crease* under all conditions cess of the melting point of bismuth, 6 to 10 pans, said The new friction facings described herein function proportions being expressed as pans by weight well srith conventional mating surfaces such at Meet or 7 A sintered friction material for use as a friction cast iron which is normally used as clutch disc aad brake facing element, consisting essentially of: iron 100 parts, drum material. It will also function in combination with 65 graphite 30 to 45 pans, copper up to 15 parts, and bis other metals providing the lubricant metal doe* not alloy therewith at operating temperatures. For this reason, the muth 6 to 10 pans, said proportions being expressed as pans by weight. metal of the mating surfaces should be chosen from met als and alloys that do not form imermetallic compounds 8. A sintered friction material for use as friction facing element, consisting essentially of iron 100 parts, with the low melting point metals such as lead, bismuth 70 graphite 30 to 45 parts, copper up to 15 parts, together or cadmium used in the friction material. with sulfur and mullite in quantities not in excess of 2% . The curves shown in Figure 3 are for two different and bismuth 6 to 10 pans, said proportions being ex frictioo linings Curve *1 is for the material diacloaed pressed as parts by weight in Example I Curve * 2 is the material using 3% 9. A sintered friction material for use as a friction fac bismuth alloy instead a t the bismuth-lead alloy, la aacfc 76 ia l element, consisting essentially of: iron 100 pans, 7 graphite 30 to 45 part*, copper up to 15 part*, and a bis 8 meat being coextensively attached at ooe surface thereof muth-lead alloy 6 to 10 parts, said proportions being ex to a strong metal supponing member. preaied a* pans by weight. 10. A heavy duty brake comprising a friction elemem. References Cited in the file of this patent consisting essentially of iron 67 parts, graphite 20-30 6 UNITED STATES PATENTS pans, a bismuth-lead alloy wherein the bismuth and lead 2.072,070 F ish er........ .......................... Feb 23. 1937 are in equal proportion* 5-10 parts, copper 8 parts, all 2,416,830 Heuberger ....................... - Msr. 4. 1947 proportions being expressed in pert* by weight, said ele- 2,863.211 Wellman ............................. Dec 9. 1958 May 18, 1965 e w . reinsch et al BBAKE DRUM AND LINING Filed Aug. 16, 1962 3,184,001 500 X F i g . /. 500 X F ig . 2. vvEvroRS to r / WReinsch Gene P Baynes / he.r Attorney United States Patent Office 3 , 184,001 Patented May 18, 1965 1 2 We have found that cold pedal conditions may be greatly lessened by utilizing a ipecific combination of 3,184,001 elements in the bnking lyslem. Thu, when using a BRAKE DRUM AND LINING Earl W. Reinsrfc, Dayton, and G ent P. Bayses, Kettering, ferrous metal brake lining such as is disclosed, for ex Ohio, assignors to General Motors Corporation, De 5 ample, in Patent 2,945,291. we have found that the colJ troit, Mich., a corporation of Delaware pedal effects are greatly lessened if a brake drum surface Filed Ana. 16. 1962, Ser. No. 217,426 formed from steel substantially free from ferrite is used 5 Claims. (CL 188--71) in combina'ion therewith. Most automotive vehicles made today utilize gray cast iron brake drums. The This in-:ntion relates to a loiquc transmitting and/or 10 combination of the metallic lining with the aforementioned energy absorbing device and is specifically directed to brakes, clutches and the like. More particularly, the invention is directed to the combination, of a sintered ferrous brake lining or facing ueJ in conjunction with a brake member including a braking surface formed from steel substantially free from ferrite. An object of the mention is to produce a combination ol elements for use ir. u to que tiansmiti.r.g and or an energy absorbing d :v k e t.r.d particularly a btake wherein the uniformity of oper.iti.r, is improved In carrying out the above object i! is a fu'lher object steel drum reduces the cold pedal effect in the order ci 25% whereby much better and more uniform operation is obtained from the braking system. A typical cold pedal test procedure is as follows: the 15 linings an j drums are conditioned by making ten stops at '/: mile intervals each from 40 miles per hour at a decel eration rate of 10 ft./see.2. The vehicle is then parked for a minimum of two hours The cold pedal is then evaluated by making ten stops at : r mile in.ervals frem Ju 40 mi f per hour at a d-;cJe;.ii< n rate of In ft / isc : ~ wherein the initial and fuu.l line presrurcs required to mair.ta.n the spe. fie d s n i:r..t,or- is K .o-Jcd i l i r o ol the invention to reduce cold p.dal cllc.'. normally picsent m automotive braking -vstei >s r.irthe; objects and ..d \.image's of the p;csen; inven tion will be apparent from the to .'owing dceruption, inference being h id to tK c-omp.im :r.g Jrawir.es vh c:.in pteferred embodiments of the present invention are clc.rlv shown In the d. ,,vi .tips M i l 1 -. ., phot, ! ... ,.ph o: " scetit n of . cash slop Using brake iir.lngs a` disclosed in the aio 'c rrcr' ' patent with a standard cn,t ir.-r, drum cor.J.tioui! r. tr.tenth stop of the schedule rcqu-Tcd 270 p s : to p ',\l...e the desired deceleration After tli. car v p..rk.-J tor the two hour rest period frnm .. fervv,.rd 'top, the first che.l step after the cooling off pe:.od required an int i. line r-.-s uis <' 320 p.s.i.. v-hi.h in be termed ir. co'd f.-'i . :,! -.-It ..1 vsties- li ths car v- . - ; i . .' 1 : - -o ' S.\I 11)10 sicei drum show.! : the f s r '.. the structure. m;t oil p<::>,! from a rcvcr,e stop, ths *: * -h e:' >p i.- a"J I 1C 2 is a photo ir.'.roe .it h o' . ..to* se.t.i n of a qutrcst jnTlal line pressure of : S ' p i le ts m r. termed eoid reverse effect;'.ne>- SAl toys steel dtiim hew .. t1. abs.-.;. of f c u l c in the ... If the stir i- parked w tli . Ik" ...i slop bifote the U'lCIOstrUetUlC. R etert trends in automotive ce-igr. and improved ro.i 1 Ci n.lii.ons h. v; made ro-.-;b;. higher speed tr.iv.i in cool me pcrioJ .aid a cont'odcJ reverse slop is made befo re the first che.k s op. the f" st cb-c.fc - n p requ:re- r.n initi:il line pre sure of 3S` p s > T hu i: also Call 1 the automotive vehicles. These I r e n 1- have requited impiovemcnt in brake Je-v:;:n end e instruction so t l inc cold riv erse eflccii'.eness It will be note., that the 1 ' : rie ssi.-e r.ricasc K ef.-.t vehicles may be stopp-.J 'itr.tr a s. distance even item I1,, h giict spec.!' In o der it' it. ike this condition pos soke, heave duly braU n ne i,. q c i .d - h,.ve K . n devu- a spcsifie deceleration to stop. :. the sc:;,, to effect .. 'n if tn e immediate previous siop w. - a tcve-v; step w h .th .r ths Ieverse stop was before r : niter lln rriffin? i ff perio i e'ped vvl.i.h arc melalii. ..n r..,..::e . nd which w.l1 v>.ll, st.ir.J the high terr.penitur . eonditums wti.ch prev.iu in the brake duiing a stop or stops from h-ch speed' These T!hus the difference between w . -i i-..ks c f l t . i 'v c r .' . 70 p.s.i. and cold reverse effc. ,-ne>s at f .s l. ! ] 15 p s i. This iliilerensC 1 ! 1e d . 1- CtC.l by the J r`v . ' temperature conditions ate si.ilieient to. in many in-tan. . z r .1 is known as harden. 1 p . d . ! 1' o^cur :n n.arn .1 c.-ii'e eh.mine of non n u ' .lie type linings incluJ.re i i ilr>\.ne when .. d iver b.i.k- out cf .. pjrking spare .r., g;;nie type material. T h s new b rale lining mateiiul then is r . q u i t " , to make a forw tt.1 Mop T h : change m wln.h is spcc.fically a sin.cr.J ferrous material ireluJrr.' graphite, is disclosed in some det ii! in U S. 1'.items 2 .945.291 and 2 .945.929. among others which arc as signed to the assignee oi this upp!i'e.,tion. These mctalhe br.ii..e-outpu: i- ne-ted reg..:Jie.-- iff` the c..r p.s J. Th. s..:ns scheduled te-i- wev mads- us-ng drum, formed fiom SM: ii'S'i steel v,,llt ,,11 other conJ i identical. In this instance th: warm, effectiveness dropp-1 friction materials have the ability to provide reasonably to 2)5 p.s.i.. the cold forward effectiveness to 230 p 'a. constant coefficient!, of frietion oscr a wide range of 'r,'` and the cold reverse effectiveness to 25u p.s i. Thus, the temperatures and specifically are capable of maintaining steel d u m narrowed the difference between the wati : the reasonably high coefficient of friction at high tempera stop and the cold reverse slop to 35 p.s.i. over the 115 tures whereby the vehicle may Ire brought to a stop with p.s.i. required when using a gray cast iron drum. out excessive pedal pressure and wherein the fiiction ma In addition to the improved brake characteristic':, st.'.-i terial remains unharmed due to the rise in temperaiuie *>0 has greatly improved tensile st'ength o 'e r tbs used gray These same materials, however, do not provide the cast iron, as is wcK known. Further, when iubstarlu.ily ultimate in cold pedal operation under normal conditions. fret from ferrite, the steel has reduced scoring tendcnci.' O l d pedal may best be defined as a reduction in effective This is a very important consideration since fie. fend, ness of the brakes aflci a period of inactivity, that is. such as is formed in SAT 1010 steel p.odue.- marked when the automotive vehicle has been standing idle for e C> scoring tendencies ar.d is not us ful in braking application* period of time, for example, the r rst stop or first few Steel offers another benefit that is commercially im stop, made require griv.cr p, !nl pressure to bring the portant. namely, due to the increased slrcngf- over gta; cai to a stop than do subsequent opetations of the hiakhip cast iron the drums m..y K m.iJe consiJe . n l ' l.ehter s.stcm. This condition, while not sirioiis ftom a safety- will; decreased wall lhi.ktiess without sacrificing ruggi .1- point of view, is nevertheless, annoying ar.d has itieJ a To ]* should be understood that similar rest it can a deterrent in some case'. toward the application of m- tnl- be obtained using cast iron drum' imed with the desire1 lie brake linings in pleasure vehicles. steel surface. Thus, when th: term drum is us:J herein 8,184,001 3 the term is sufficiently broad to include any combination providing the braking surface is substantially free from 4 or energy absorption over a wide range of operating temperatures. ferrite. In place of SAE 10R0 or 1085 steel any Other steel 2. A torque transmitting device com pliant a sintered ferrous facing and a mating surface cotafetmg of itecl which has a structure substantially free from fertile is H substantially free from ferrite. useful, for example SAE #8660, #9260. Alloy steels 3. A brake for uae in an automotive vehicle and the of this character may also be used where specific physical like, comprising in combination; a sintered ferrous brake characteristics are desired which may be obtained from lining and a braking surface cooperating with said lining, the alloy. said braking surface consisting of steel substantially free In general, sintered ferrous linings and/or facings hav 10 from ferrite whereby the combination of the sintered fer ing a sintered ferrous base and including graphite in quan rous lining and the said steel braking surface effect uni tities above 10% with or without well-known friction form braking conditions over a wide range of operating fortifying and/or modifying materials, may be used effec temperatuies. tively in the combination. 4. A brake for use in an automotive vehicle and the Any steel drum having a metallopraphic structure sub ]5 like, comprising in combination; a sintered ferrous brake stantially free from ferrite when used in combination with lining and a brake drum for use as a rubbing surface a sintered, ferrous brake lining material will offer im against said lining, said drum having a contacting surface proved operational characteristics, particululy in the cold consisting of steel substantially free from ferrite whereby pedal ranee. Such improvements arc easily noticeable the combination of the sintered ferrous lining and the said by the operator of the vehicle and lessen the difference in 20 steel braking surface effect uniform braking conditions pedal pressures required to bring a car to a stop unde: any over a wide range of operating temperatures. giv en set of conditions. 5. A brake for use in an automotive vehicle and tbe It is to be understood tti.it the prineiples in'c'ved arc like, comprising in combination, a sintered ferrous brake equally applicable to disc br.ikes. drum brakes, clutches lining and a braking surface cooperating with said lining, a n d 'o r other torque transmitting and or cnergv .ihsoib- 25 said braking surface consisting of SAC 1080 steel sub ir.g device-. wherein sliding or rubbing cngngenn.nl occjrs stantially free from ferrite whereby the combination of bet era the sever..1 element- of the structure. said sintered brake lining and said SAE 1080 steel braking Wb is the embodiments of the present invention as he:cir disclosed, constitute preferred forms, it is to be surface effect unifo'm braking condili.ro over a wide range of operating conditions. under:tood that other forms might be adopted. 30 W.'..,; is sl.umcJ is as follows: References Cited by the Examiner 1. A torque transmitting and energy absorbing device, UNITED STATES PATENTS i ..lgtising .n combination: a driving and a driven n u m 1 900.804 3.73 C ro w e ............- .................188-- 218 ber herein one of sad members comprises a sintered fer- ,,. 2.09-.125 10,77 Le J e u n c ........................ . 1 8 8 --218 ro.iv surface and wberetD the other of saiJ members con 2,945.291 7/60 Ankeny c: al _________ 29-- 182 ? sist oi a steel surface suKiant.ally free from ferrite where by the combination of the sintered ferrous surface an j the ART HI 'R L. LA POINT, Primary Examiner. s.-.i-.l suet surface effect uniform torque transmission a n d ' EUGENE G. BOTZ, Examiner. JUNE 1950 AUTOMOTIVE ENGINEERS THE varied properties required of a brake lining material calls for careful selection and blending of its ingredients. Lining requirements are: . 1. Correct coefficient of friction, which is influ enced by temperature reaction, aging qualities, water reaction, and oil a n d g rease re a c tio n ; 2. Durability; Automotive 3. Relative freedom from any tendency to score drums; 4. Quietness In operation; and 5. Nonoffensive odor. . Lining friction coefficients generally run between 0.20 and 0.40. Manufacturers usually describe lin ings as having high, medium, and low friction co BASED ON FA.PEP* EV efficients without specifying friction value numeri cally. It's not hard to compound a lining with an initial specific friction coefficient; but to produce a lining with uniform braking performance under various operating conditions takes much compound A. J. Carter Assstant Department Head Poster P.as: :s Laboraron Crr.se- Corp ing study and laboratory and road testing. The ideal lining would have a constant friction coefficient at high and low tem peratures, under wet and dry conditions, throughout th e lining's life. There is no such lining. All linings disintegrate under high braking temperatures. Cnemical and physical changes either increase' friction coefficient (build-up) or decrease it (fade). With fade, if lriction characteristics return to their initial condition, the lining is said to have good recovery properties. Satisfactory linings fade slightly with each brake application, but recover immediately after cooling Linings producing build up in friction coefficient are not satisfactory Friction coefficient may increase ^r decrease with age When it decreases, it develops a hard pedal. Some linings harden and tend to score drums and be noisy. Other linings are sensitive to water on the fric tion lace, with effects as pronounced ns those from temperature. Moisture alsu causes "morning sick ness. ' Iron oxide forms on the drum and gives high friction reaction during the first two or three stops made after the car has been parked over night. Be cause of contact with oil and grease m service, lin ing.should have some resistance to there materials. Linings also should wear slowly and uniformly. This insures more consistent braking action by con tinually renewing the friction surface. Negligible wear may produce a glased friction surface. Certain ingredients tend to score drums. Steel dru m ; score more readily th a n cast-iron ones. Brake system quietness is a function of the lining as well as other fa c to r1'. Ingredients m ust uci pro duce offensive odors at high braking temperatures. Good compounding ingredients may be di5c.'.rdr d because of this limitation. Brake lining materials derive their properties from fillers, binders, and wear-enhancing ingredi ents, such as those in Table 1. Selection and per centages of ingredients used varies with the type of lining. Chief lining constituent is Chrysotile asbestos, used as the primary reinforcing material. Chemi cally, it is an hydrous m agnesium silicate (H4 Mg, * Paper "A ,,-rr'or-v" c'-ate L-.:ng Mate - a < ' v..=s r ' : "" . 3 s' Si: 0 9). The m ineral fibers are ^ to 6 in. long. Anp_,a' Derrp.t Jan _ e- C (Ts paper a ava^b'e ,n fu'l in rr-./'iiithographed fpr-i ren 5.AE Spec* Pl. ' - . - '$ i 4 Under high magnification the fiber looks like many Pr re 2~C to members, "2d to "o r--.em1. ers ) finer crystalline threads bundled together. Diam- ; Binders Elastomers Rubber OR-S Buna N Neoprene Phenolic resins Oil modified phenolic resins Cashew nut oil resins Drying oils Bulfunzed oils > Table 1-- Brake Lining Ingredients Reinforcing Chrysotile Asbestos Filler* Nonieinforcing Barium sulphate Calcium sulphate White lead Lead carbonate Clay Asbestine Friction Modifying and Wear Enhancing Agents Cashew nut liquid products ipowders' Rubber and synthetic rubber Ground rubber tire scrap Iron oxide Metals--lead. zinc. b"ass Lead salts Tale Graphite Bituminous materials Abrasives Curing Agents ind Accelerators Standard rubber and resin primary and secondary curing agents and accel erators 9 9 20 SAE IOURNAL ( BRAKE LINING MATERIAL Ingredients Hold Key To Service Behavior etcr of the smallest fiber which can be separated is reducing cr inert atmosphere. This prevents oxida about 0.00003 m. tion of the metal to an oxide and permits it to func Asbestos makes a coed friction material because tion as a friction stabilizer. of its heat resistance, chemical resistance, flexibil G raphite in lining compounds im parts a lubricat ity. low therm al conductivity, and hardness. Its ing effect for smoother stopping. It can be incor reaction to heat is particular^1important. porated in the hard rubber or added separately. The asbestos fibers start losing their water of Some compounders see two advantages for graphite crystallization a t about 600 F. The loss rate in encased in rubber. First, it does not interfere with crease- with tem perature and become rapid a t 1000 flow of the resin binder during curing. Second, F. When the water is driven off. asbestos looses its graphite is released for its lubricating action only crystalline properties : nd Incomes a powder. As- a f t i r the rubber Is softened by high braking te m ! be-'tos fiber breakdown to powder with heat make? perature. pn-'ible rejuvenation of the lining's fru lion surface. Iron oxide in small am ounts sometimes i used as Today's brake lim ner would be impossible if heat a friction-controlling element. It tends to have a generated in braking a car decomposed only organic sc-li-poli.shing action which partly controls surface materials and changed asbestos into a hard, organic frictional properties. fused layer of abrasive material. The compound usually requires large amounts of Poor heat-conducting properties of asbestos help inorganic fillers to produce frictional effect.'.. This keep heat from penetratme. deeply into the lining. necessitates an improved friction stabilizer that Tins would produce civ mica! chance, in binder functions over a wide temperature range. Organic m att rials a r c' would harm lining fr.ction character- modifier.' such as rubber, ground ruboer scrap, 15-'tiC S . pitches, and gilsonite- function besf over narrow Asbestos fabrics have a Ira. tion coefficient of tem perature ranges. about 0.35. This is within the 0.2 to 0 4 range A powdered product made from cashew n u t liquid aiour.d which satisfactory braking systems h a w is. cne of the bettei friction-stabilizing and w ear beer, designed. enhancing agents used today. This material works Brass lead, or lead alloy wires used in woven m a satisfactorily up to tem peratures of 000 to C50 F. terials strengthen the yarn Some claim lead su r Tire scrap particles function up to about only 500 F. passes other metal- b e c a m e it stabilizes the friction About G to 8To of dust is needed to improve wearing coefficient, act- as a dry lubricant to prevent drum qualities. scoring, and inhibits iorm.nion of abrasive particles Ground- rubber tire scrap has been, and will con on the friction surface. tinue to be, widely used because it is a cheap raw Metallic powders, such as zinc and lead, improve material. Other friction modifiers--such as pitches, performance at high tem peratures. Limitation gilsonite. coal, and petroleum coke--can be used in with fine ler d is that it oxidizes easily to litharge, limited quantities oru.y because of their low te m which promotes oxidation m unsaturatort organic perature resistance. Braking temperatures destruc compounds. Some believe these powders help tively distill these materials to form tarry or pitchy break the continuity of the friction surface film residues at the friction surface. These increase the during braking action. Larue am ounts of metal friction coefficient a t low tem peratures. But at high (409c). such as brass chips, are added to linings for tem peratures, volatile m aterials may be driven oft u ry high temperature req lirements. too rapidly before formation of tarry products, los Brake lining compound' rs also add lead to com ing their effectiveness. positions in th e form of organic salt. High t e m Researeh today is aimed at. getting binding m a perature liberates it ns finely divided h a d in a terials with high heat resistance. Currently the U-'NE 195C 21 Fi*i I-- M fh$ brake shoe shows, borocd limn? nukes avaiLb1* fwicc the us:*! lining and v *tjalK eliminate' <*un -cere Lists New Need With Bonding Lining Acid b o n a a t i i i t y as a s i;:t h lim n g reej a ire n m :a t . ; vIvi.-.es S . CV T i l d e n , T h e P e r m .a fu .s e C o . T h e ad vi n t r -1 bonded broke lin in g s n take-' th is a n ,\.A . T h e ; e ll'S o. n a m ,- a tii h : n se t u p d ll . r b k r ; r " tv;h ' ir / :-.an b a r d s t r e u " ` i : : e . , u i v m 1:.f. 1 o f 0 ) 0 ; 1 : T ; . m owe -. 1 ' .'J .`-h-',u r c. t n o t h <: J ' .Vif) V on :< l - ; , 1 1 - in . s c - r m e r it , T h a t ) ' a :i y j v A fiv e t in . . ' ! f m a x i m u m s ie a:* f ! f<. ( x - e r e cl o n lin k '. m: ) ;y a s i m u l a t e d cm. V I *: u ;c y .-t o u w ;1 . i 1 e cmcel<' l a t : ' r. A .I l i n i n ' ' f:a c t o r s j h '.icl ic in g tcocr.i! b o n d a 'n ' l ' i ; i ; . .v * * c.t w c - t a b li h id . B u i ' <l h v* bi *n ) - 'n 0 1(, l ' > d th-. c ih r t o f p o r m n y S t IV : L. ' V . . : )\" 1.. cl m i ; r r<v.d 1a " ;. a b w r b m 11. V m i b' : ' :. B o n d im s u ita b ili f\ also ca lls fo r a v a il ..o iu ty o f t h e e n tir-' 1m u m t h i c k n c ess fo r u s e . T h a t * V-i :y w ir e - b a c k l i n i n g s a r e n o ' s u it e d f o r b o n d - in ;j . T h e y ca : be- a s e d cm.l y d o w n to th .o w i r e h a.e k in g ; rt i t e r t h a t t h e y -.co re t h e d r u m - W i t h w . re b a c k m u . t h e p ro rn i.-c c1 d . 'lio le W '-.u: f ro m O*j>. tie d l i : c a n : ret be re, u izo u. T y p i ' uu n ; il m e x t r a '.v a. v a i l .ibl- w it It In. d i n u n . tin - ! n u : .: i; : F . . ' . T r .n b u lk - ' UP V. ' * .1 b e n d - li : W V w a rd t . n ' i l t : i* `%CT- vm, j ; 1^,-1 : j 1-* e l; 1L h r e u - h to t . h ^ ? a t t h e c e ,. t r . i : t a . r u n t ; a l -m .1. N--'/.' tit*' . A %:. s * <ii " i n s c o r e . .x c - m f o r th-- o-.ver i c l . " p n 11c : . : ih t - cam e fro m a c tu r.: tr.e ta l-tn -ir.e k .l c beuwef-n b ra in - si. m v i v ^ ' a u . V i k a n ]io tn )- o ;;r th a b / : . : ; : : . : . . -1' p i'cive In - p a t h I ' T ('' ill ;: f>t : ' _ )i . , th e b r a k e s h o 'v-, b a c .mi- ] ) k h c . :-.\h I : p ro - m i '.' ' a In n ;a t v. . t i n a ' t l ' e m . *y.. i; u a l.iy p r e s e n t i i r W - V I n n : m . i i i i h i . c' : : : a ' j M t ' ; n r , v - m he u c r e . dry mg oil.1, r iboi-r. and bituminous ir.aieri.Li-. Ma-' im p ortant croup is the synthetic' re.-:n:-. Oil modilied ph.-nolies arc- moatly used. Syn'nc-tie ic.'.in.- Imld much promise because they can be svnthetizect in the laboratory tc meet desired Liiutiiic material requirements. Available resins vary in their properties Some can be used alone, other* must he used, to jo th e r with nature:, synthetic, or reclaimed n .b b ei Oi modified ty p e s also a re commonly u m c \. it h th o se rubbers. Used as a binder, rubber or GR-c> m ust be vuKta.1- ized to function properly. In lininr composition? they usually are cured to a h ard rubocr n ith 2a to 4U'f. su'ii.r a.-.- the vulcai icinc aeor.t. Their rela t e ely low copisnir.-j and d c - c c m p o - i t e m p e r a tures limit rubbers clone ns. binding averts. In the f ut ure It may b< pos-ublc U .--yi'h 'ir.e rubber polymers th at will make satisfactory brake lining binding materials. Some day tpecial rubbers may be expressly mt.de for this use. Drying oils, used for many years in brake lining formulations. are limited because of control oi polymerization (h ardening). They are used in aitettrinz type and v even linings. Wide use also is made of them as a binding component in modifying phenolic resins. tThe paper also tells how fabric and molded lin ing;- are made.) 9 3 22 SAE JOURNAL P*' H .? * *' ! *_i. :! : ;i| I J__ ' J p u f * 5 ; i ^.pVT j v :. I I r- . f CD V t* ` '1. * : 'i ^ . , ' >-I *. M - j * C 4 t/7 J JUNE 1979 ' rl :-; j. j . [u tu re T u rb o c h a rg e rs 4 Aer 1 H * | j! 'l l i l lrwm ni \ if f \sf i *3 a ! TiV B r. l l . 1 it *^1 I 1 L `i T , :} ! 1 5 -j _ ; .* *; -1. ; ViWr 11. - ** i 11 j; : ? -I . 'i * . -! m a m ic s A ir b a g G a s G n r a n t s ; j f i: Designers can affect frictional coefficients of brake ana clutch linings by blending ingredients in their binders. Friction modifiers tailor brake New requirements for friction lining materials exist because of the elimination of asbestos in brake and clutch compositions and the use of small pads for down sized and compact cars. Semi metallic compositions generally need some friction modifiers to reduce squeal and wear and pro duce friction characteristics that are less temperature-dependent. Research on solid friction control additivies at Dow Coming has pro duced new technology by which friction and wear properties can be tailored to specific require ments. Friction modifier* Friction modifier additives are synergistic blends of tem pera ture-stable materials which can be incorporated into various com positions to provide specific fric tion, wear, and load-carrying pro perties. Concentrations of one to six weight percent can reduce noise levels and dependence of fric tion on speed and temperature. Additives, such as cashew resin or graphite, have been used for many yean to control friction properties in brake and clutch compositions. Friction composites are composed of a balanced mix ture of resin plus additives and generally contain over a dozen ingredients to achieve desired 74 characteristics. In Europe M0S2 (molybdenum disulfide) has been u tilized 'as a friction modifier for harder brake pad compositions. Comparisons were made between M0S2 and a composition termed by Dow Coming "Friction Modi fier A" . Phenolic retin composition* Phenolic resins are the most common organic binders used in friction composites. Compositions of phenolics with high loading of M0S2 powder and Friction Modifier "A" were tested using an Alpha LFW-1 friction and wear testing machine. Phenolic resin by itself does not have the best lubricating properties. Addition of MoSs or Friction Modififer "A" provided a reduction in wear and friction. Generally, the phenolic resin with Friction Modifier "A" gave lower initial coefficients of friction and wear values as compared to an equivalent weight concentration of M0S2. Coefficient of friction for the Friction Modifier "A" formu lation changed less with time than the base resin or MoSi composi tion. Additional tests at a lower load of 13.6 kg and higher speeds re vealed that formulations with Fric tion Modifier "A" gave a more con stant coefficient of friction with changes in speed, load, and time. At higher speeds and lower loads, no difference in wear was appar ent between M0S2 and Friction Modifier "A", but wear was sig nificantly lower than the base re sin. Composition* Three different brake composi tions were categorized as follows: Class A--High in asbestos and organic components Class B--Less asbestos and or ganic components plus some inor ganic components Class C--Semi-metallic non asbestos composite Class C prototype--Semi-metal lic nonasbestos Composite with 10% Friction Modifier "A" . Table 1 lists the different char acteristics of the three classes. The brake compositions were test ed on the LFW-1 test machine. The results of the testing are listed in Table 2. Good corre lation between the LFW-1 tests and the general characteristics provided for each of the classes was obtained. Complete correla tion existed for the wear of the brake composite and the metal mate, and very close correlation existed with noise and friction properties at low and high tem peratures. Class C, which produced the