Document NEn4x892dXd2NQo83Okq6z04p

FILE NAME: Allied Signal Bendix (ASB) DATE: 1960 July 19 DOC#: ASB203 DOCUMENT DESCRIPTION: US Patent - Frictional Material - 291 United States Patent Office Patented July 19, 1960 1 2 eventual breakdown of the materi ils used in the brakes In most cases, nonmetallic brake materials are not use 2,945,291 ful at temperatures above 750 F. and such temperatures are frequently exceeded in repeated high speed stops under FRICTION AI MATERIAL 5 extreme conditions Thomas G. Ankeny. Birmingham. Mich., and John 'V. Amen, Dayton, Ohio, auigoon to General Motors Corporation, Detroit, M kb,, a corporation of Delaware Since the trenJ in automotive design is tov ml heavier and or higher poweied vehielcs. it is apparent that the friction mulct.als U'cJ in the brake and elmch surfaces musi be improved in order to keep up with the develop Filed Nov. 28, 1958, Ser. No. 776,973 10 ment of the industry 8 Claims (Cl. 29-- 182.5) It has been found that metallic Inetion materials offer an interesting field of development Flow ever, most metallic friction m u eru h while highly satisfactory, for example, in wet clutch applications are nest useful for This invention relates to friction materials and is par IT) hrake-s since they tend to squeak and grab in the dry ticularly concerned with ferrous friction members for use condition Furthermore, due to the abr..sion of the mate as clutches, brakes and the like rials in the dry condition, much elf the friction facing is This application is a continuation-in-part of applica abraded from the friction 'iirfj.e which. in turn, self- tion S N 5 4 0 4 2 . filed October IT, 105V now abandoned ..giuuv ales the wear condition I a: ;!>. i n,o; e. lhe noisi An object of the invention is to provide a ferrous fric 20 ness of these materials has made thc.n unsuitable in the tion facing consisting essentially of iron, graphite and past for passenger vehicles molybdenum disulfide There arc. however, man. aJv.images m lhe use of In carrying out the above object, it is a further object metallic trietion materials, some ol tin mote important of the invention to form the friction member from a being ability to withstand high t, nper.:ti;i. conditions, intered m-'stuic consisting essentially of iron powder, 20 abditv to withstand hi..'her eng..'in-.- p;. 'tires and. in graphite and molybdenum disulfide wherein the graphite most cases, longer wearing characteristic' makes up between one-fifth, tnd one fourth of the weight We have developed a frution material wh.,h overcomes of the member these past disadvantages ot mm 1: . fr;. >n materials A still firthcr object of the invention is to provide a when used in the dry state and which h..s maintained ferrous friction member where-n the member consists 30 all of the . J\.inijgcs of m d a '!-.' f.i. tig mat,rials We essentially of graphite i.irgng between 20'. and 25r< h.ve found that our ftiction matvti.t1 v l-.c i I m eon b' weigh: mol'bjenum doulfide between 2V and fi'V junction with a di-c or bund t-pv b'ake. will outlast be weight with non nuking up >.uNt.:n!:.iil> .I' the re nonmetallic ftie;ion mutetiVs m in;. arid will not mainder Another object o? th. invention be dvi.-teriouslv atTeeied ,.i ih. hi.) t.sip,:..:..;,. reached to provide the fvr- .30 during repeated high 'need stop- In t.-et. we e tests show rom friction clement a- heretofore disclosed wherein the that the pres.nt ftiction m..'.r,i! v I! ojt ve..r several clement is co ex tc .vdy bonded to a strong metal sup siic of convcnt.onal nonmvtjlli. fr . i -i;i -t material under porting member tor facilitating mounting of the friction identical operating conditions Fuitlu: s,-.- the met.illie element friction material dots not exhibit th. favl.--o.it of frictional More specific.'lv. it is an object of the invention to 40 qua'iues normally present :n nut act..!1;e m.-.l.rials when provide a sintered ferrous friction facing consisting essen cvcessive temperatures are encountered Under actual tially of 20't gr.iphnc. 5V molvbdenum disulfide with road conditions, the present friction mat- o.il operates substantailly al! the icmainJcr being iron wiih or without smoothly and silently throughout cv.cn led use In fact small additions of modifying materials wherein said per the facing material operated well undei i.-s's , .uprising centages are expressed on a weight basis 46 ten consecutive stops front a maximum vpeeJ of one Further ohic,!- and ..dv.tntages of the picsent invention hundred miles per hour, a cotid.'ion wh-.h v.u.'d not he will be apparen1 from the following description reference duplicated with nonmetallic .lines which l.uled com being had to thv accompanying drawings wherein pre pletely after three to feu.r of such stops ferred embodiments of the present invention are clearly Our new fnciion material o a sinier.d fert.-a.s material shown In the drawings 80 having varying degrees ol porosin and m.iJo frvmi a mixtuie consisting vssvntiallv of non powder er..ph:tc and Figure 1 is a view ,n perspective of a typical brake molvbdenum disulfide to tfus basic t.-.nq 0 ln-n Jx. band added small quantiiiC' ol siillar and .eia iv. niaieruls Figure 2 is a view in perspective of a clutch disc such as . aleined nuilhte loge'hci vvnh copn,-i and lead Figure ? is a view m perspective of a clutch or brake 66 foi modifying the action ot lhe Irid.on material The disc for use in a clinch or brake pack friction maietial o pref.-i.ibiy bond..! i.i ,, sjron-.' metal Figures 4 and 5 are charts showing a comparison be support through which it m .v be suu.ihlv ...-.,,ic to the tween convention. ! and metallic brake linings in de brake or dutch median,'in m wh..h it is to be subse celeration testy quently used D,.e to the . .en.e ,.| .. |.,igc quantity of Modern automotive developments have imposed ex 0 gr.,phne. the ma'erial ili'es n-u have ,i high decree of treme operating conditions on the conventional type of flexibility and is not re.ut;iy bv-ndahle and. iherefote. the clutches and ta'akcs The friction surfaces of conventional clutches and brakes arc usually composed of molded non strong metal support such as a steel backing is generally preferred. ' metallic material such as asbestos, cotton timers and the Spcvihe.illy, tbe m tvi. I contains pi. aline in quantities like bonded together with a synthetic resin such as a 06 of from 2o', io 25 b> weight together with molyb phenol-formaldehyde resin, the mixture may also include denum disulfide in qu intnies id trmi 2'. to 6V by friction fortifying material' This mixture of ingredients weight with substantially .dl the lent under being iron is molded into a brake band or disc surface which may be The material is m ide by nuving the lngiedients in finely bonded or riveted to a metal support. While these fric divided form wherein, foi example, die non pow Jer ranges tion elements and facings are satisfactory under normal 70 between I5u and 325 mesh |h,s imxiuie is then driving conditions, it has been found that repeated stops briquetted to the desired sh..pe under briquetting pres from high speeds causes a tremendous overheating and sures ranging from 40,000 to Joo.utiO po.mds per square 3 inch, preferably 1 70,000 pound per square inch The briquettes art next sintered for about 45 minutea at a tem perature ranging between 1150* F. and 2050' F. under e e m a lu m condtuoo*. (or example, 11 UctayOraMU, in- r r i f i l i u h burned natural pee, cracked ammonia 01 hydro- gaa. The resulting materia] present* a highly desirable friction material that will withstand high temperature*. -- iu frictional qualities over a wide range of tmn- paratnm , and which i* long wearing and quiet In moat caaes, a* previously stated, it h desirable to bond the mqperia! to a strong becking member, and tha is accomplished by placing the briquettes upon supporting i b l of steel that have preferably been flaah-eoated with copper A numb of these "sandwich" art stacked on top of one another with suitable spacers therebetween and the bonding is accomplished with the Hack under pita- hhc. A procedure of this character is fully daclosed 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 poesible to first sinter and then bond It this case, the briquette* 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 and makes it easier to handle. The preaimered briquette it than assembled with the backing member and is bonded in the usual manner at about 1750' F. for 30 minutes. T b e* conditions may vary, for example, the bonding tem- pvature may be between P 5 0 ` F and 2100* F while Lie time may be between 20 minutes and 45 minutes varying invnnely as tbe temperature During the bonding step, tha porous pan is completely sintered. These variations in operating conditions may vary widely and are not critical to 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 it bnquetted at 80,000 pounds per square inch and is sintered on a steel support ing member of tbe desired configuration which bat a flash copper plate thereon for a penod of about 45 minute* at 2050* F under pressure whereupon tbe material forms a strong sintered ltyer coextensively bonded to the sup porting membe: The friction and wear characteristics at this material may be modified by small additions of sulfur and ceramic materials such as 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 acts as a friction modifying material and generally raise* the coefficient of friction slightly. In aay case, these additions are optional and should not Hicend 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 iron powder may be cboeen which contains sulfur and insoluble ceramic materia! within the ranges noted as impurities thereui Similarly small additions of lead and'or copper may be added to modify friction characteristics at is welt known in the art For example, copper up to 5% by weight and'or lead up to 5% by weight may be added T h e modifications prove useful under certain conditions. Our invention, 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 tbe remainder of the element consists essentially of iron with or without the modifying ingredients set forth herein. 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% Acheaon graphite 3% ISO mesh copper powder 5% 100 mesh lead powder 5% 100 mesh molybdenum disulfidr .75% calcined mullite 15 66 25% 100 mesh reduced iron oxide powder containing combined sulfur therein equal to 1% of the iron This mixture of powdered materials is briquetted at 70,000 pounds per square inch and may be sintered on a steel supporting member which has been flash-copper plated for a period of forty-five minutes at a temperature of 2050* F. in a nonoxuiizing atmosphere under pressure The powdered mttenal forms a strong, sintered layer coexteasively bonded to the supporting layer. 2g 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 material in quantities equal to about 1% and .75% re spectively of the total mix The mixture of these powdered materials 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 40 4.7%5%1s0u0lfmuresh molybdenum disulfide .65% calcined mullite Remainder 100 mesh reduced iron oxide powder The same procedure for forming the material and sintering 46 the same as in Example 2 may be followed Example 5 21% Acheson graphite 4% 100 mesh lead powder M 5% 100 mesh molybdenum disulfide Remainder 250 mesh reduced iron oxide powder con taining combined sulfur equal to about 1% of the total mix. ,, A mixture of this material may be formed and sintered 88 as in Example 2. In tbe drawing, several forms of the friction member fleecribed in this disclosure are shown For example. in Figure 1. a conventional type of brake band 26 it shown which has a ferrous friction surface 22 and a metal 80 supporting 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 sandwich under pressure in a suitable furnace for sintering Figure 2 shows one type of clutch plate at 26 "s which includes a tplined hub 26, a steel disc 96 and friction surfaces 92 bonded thereto Tbe friction surface 92 n a y he provided at both sides of tbe dutch (as sbanm) if desired . Figure 3 (hows still another form of clutch or brake * at 94 In this form, the steel disc 96 supports a friction mrfao* 96 at one or both sides thereof and the disc may be tptinod es at 46 on the outer periphery or as at 42 at tha in n periphery thereof This type of plate is gen rally uaed in a pack wherein alternate piefee are spibsed "* at the inner and outer periphery respectively These a.M t.M t 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 disclosed in Almen and Carnegie application S.N. What is claimed it as follows' 392.596, now Palest 2,733.797. u>i|Tit^ to the > u i|M t n I. A new article of manufacture, comprising, a fric 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 209t at one minute interval! at 50. 60 and 70 miles per hour lo 2 5 graphite. 29t to 6% molybdenum disulfide and with a commercial molded nonmetallic lining wherein the balance iron. tbe rate of deceleration it maintained at fifteen feet per 10 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 229 required to maintain constant deceleration Thus, at graphite. 4 9 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 K> 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 fnc 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 209 that tbe pressures required for the first stop are con to 259 graphite. 2 9 to 6 9 molybdenum disulfide, and sistently lower and that the pressures required for subse the balance iron wherein the iron includes as impurities quent stops are substantially constant No failures were insoluble ceramic maierial up to .759 and sulfur up to noted All tests were made on identical equipment and 19; 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 59c by weight each lining tested was of a 40 8 square inch area while the 3u 7. A new article of manufacture, comprising, a fru- 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 209< to 259t, molybdenum disulfide 2 9 to 6 9 . sulfur to a porous ferrous friction element Deluding a relatively up to 1 9 , mullite up to 7 5 9 . copper up to 5 9 . lead high percentage of graphite together with significant quan up to 5 9 and the balance iron, said quantities being ex- tities of molybdenum disulfide wherein said element may 30 pressed by weight or may not contain small addrions of wear and friction 6 A new article of manufacture, comprising, a fric modifying ingredients The fnction elemem may also tion facing consisting of a sintered compact of graph,:e include an imprgnant within the pores thereof if it is 2 0 9 , copper 3 9 , lead 5 9 . molybdenum disulfide 5%, desired for sealing the pores against the ingress of the calcined mullite .7 5 9 , sulfur 6"9< 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 ufrnicdteiorsntaolodchathraactteirmisptircsgnoafntthse mmaaytenbael useTdhewreitfhooreu,t itdeis 45 parting from the concept of the invention Throughout this specification, the term ceramic material it used together with mullite as one embodiment there oonf.ly Iatnids tothbaet ucnladyesr,stosiolidcathamt atghniseseixuammpolexidise,illmusitcraativoer 50 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 1, 1946 17, 1956 5. 1956 26 1956 any of the other refractory ceramic materials may be used with varying useful results. July 19, I960 F i . e d Ndv 26. 1956 T G A N K E N Y ET AL ERIC?ICS MATERIAL 2,945,291 2 Sheets-Sheet : A3M/01XV WMHA l i f t * /Vir r s u n e / b u / r t / s Jmuarc /ocA