Document Oo61bO82G9XzKDYBpM0q5neL

FILE NAME: Allied Signal Bendix (ASB) DATE: 1998 July 31 DOC#: ASB032 DOCUMENT DESCRIPTION: Letter from Patten Agent with Attachments Literature and Patent References on Bendix STEPHEN L. BERGER, P.E. PATENT AGENT 4418 Pleasant Valley Court Oakland, CA 94611 (510) 622-2345 Work (510) 658-2256 Home July 31, 1998 Walter Weathers 333 Clay Street, #4440 Houston, Texas 77002 BENDIX REFERENCES AND RELATED MATERIAL Dear Walter: I have enclosed literature and patent references on Bendix (both Aldrich and Kwolek), some patents assigned to General Motors, a 1950 article by a Chrysler employee, and a 1979 general reference comparing different brake linings. Most ofthe references should be self-explanatory after reading the enclosed three page report I wrote for NRDC in 1983. The report also details a telephone conversation I had with Aldrich in 1983. If you have any questions, I will gladly discuss them with you. Sincerely, Stephen L. Berger, P.E. Stephen L. Berger 6651 Saroni Drive Oakland, CA 94611 June 22, 1983 Dear Barry, Here is the report on asbestos-free brakes for NRDC. I looked through the Engineering Index from 1970 to . April 1981 1983 and the Index for SAE Transactions from 1974 to The only reference that might be of interest and which I could not locate here is a book entitled Friction Materials; Recent Advances by Louis R. Newan (it might be Newman) published in 1978. It is based on patents and mentions commercial applications. Sincerely, ASBESTOS FREE BRAKES Stephen L. Berber June 22, 1983 Possible replacements for asbestos brake linings (pads) can be divided into two groups: (1) the semi-metallic friction materials, snd (2) linings in which the asbestos fibers are replaced by other fibers, specifically Kevlar (du Pont trademark) aramid fibers. The following references describe the semi-metallic brake lir.inrs. 3AE Transactions Paper No. 710391, by F. William Aldrich from the Bendix Corp. This 1971 paper describes the advantages of semi-metallics: improved wear resistance; improved fade resistance; improved high speed effectiveness; improved frictional stability; minimal noise; and excellent mating surface compatibility. The paper seems to imply that semi-metallics are useful as both disc and drum brakes. SAE Transactions Paper No. 750874 by John F. Kwolek, at the time irom the Bendix Corp. This 1975 paper is directed to semi metallic solid rotor disc brakes in small cars. Reviewing the history of semi-metallics, the paper states that they were first developed in the 1960*s and first used on foreign vehicles. Police cars and taxicabs were also equipped with them. In 1970 in this country, semi-metallics were used for the front disc brakes of police cars. Additional costs were apparently the only reason widespread usage did not occur. "Semi-metallics are currently being produced for one domestic vehicle eouioped with solid rotors. Combinations of organic snd semi-metallic psds are being used on a domestic 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." The above paper mentions a 1974 U.S. patent 3 835118 (enclosed) to Rhee and Kwolek 8nd assigned to the Bendix Corp. This patent is the only place I found which actually describes -2 - typical semi-metallic brake pad formulations. The patent discloses coarse sponge iron particles as a friction modifier. The patent also mentions that "one of the major obstacles to the acceptance of semi-metallics as a friction material has been the poorer wear resistance of the semi-metallics (compared to organics) when operating at temperatures below 325F." (col. 3, line 66 to col. 4, line 2). The brake pad of the patent apparently overcomes this objection. SAE Paper No. 790717 (abstract only is enclosed) by Harry M. Schiefer and George V. Kubczak of Dow Corning Corp. This 1979 paper describes a Dow Corning friction modifier for semi metallic brakes and clutches to reduce squeal and wear. An article, based on the above 790717 psper, in Automotive Engineering entitled "Friction Modifiers Tailor Brake and Clutch Characteristics." This article gives more detail than the abstract and compares the oroperties of the different classes of brake linings. Semi-metallic brake linings (because of their hardness) without friction modifiers creat much noise (the saueal one hears from many European cars). A telephone call to Aldrich at Bendix in Troy, H.Y. (516 273-6550) revealed the following information about semi-metallics (1) some European manufacturers have used semi-metallics for about a decade (2) companies are very secretive about their proprietary brake formulations and, therefore, few articles giving details are published (3) semi-metallics work better than asbestos linings, but cost more (4-) more than half of GM and Chrysler disc brakes are now semi-metallics (5) brake manufacturers will soon have to stop using asbestos because it will be too expensive for them to meet the proposed OSKA standards. A telephone call to Schiefer at Dow Corning in Midland, Mich. (517 4-96-4000) did not reveal any new information, but he did confirm that brake formulations are hard to find in the published literature. I do not have information on changes in manufacturing equipment or processes for the semi-metallics. - 3- Brakes in which asbestos is replaced (the basic formulation remaining about the same) are best exemplified by SAE Transactions Paper No. 800667 by Halvsr Y. loken from du Font. iThis I960 paper suggests replacement of asbestos by a combination of "a low cost inorganic filler with higher cost reinforcing fibers added for strength snd crack resistance. This approach would in principle make it possible to continue to use the production methods that have been developed for asbestos-based friction materials." The paper presents a table which lists the advantages and potential problems of various reinforcing fibers for friction materials. The problem with Kevlar: "Cut forms...require special attention in mixing because the fibers are tough and do not break up but tend to clump together on prolonged mixing." The paper does mention that Kevlar reinforced friction materials can outperform asbestos friction materials. However, Aldrich told me that Kevlar is very expensive (shout $6.00 per pound compared to about $0.25 per pound for asbestos) and that this fact might limit the commercial applications of Kevlar. On the other hand, the formulations in the paper use only 5# Kevlar, but premium quality asbestos linings use 50-80# asbestos. Semimetallics cost less than Kevlar-based friction materials. Also enclosed is U.S. patent 4,119,591 to Aldrich and assigned to Bendix. This discloses a friction material reinforced with steel and cellulose fibers. Aldrich said that this patent is "worthless." There is also enclosed an abstract of SAE Paper No. 800979 entitled "Performance Characteristics of a Non-Asbestos Cellulose Fiber Comuosite Friction Material." No evaluation of this paper can be made by me. Lastly, there are two U.S. patents, 3,870,561 assigned to Johns-Fanville ana 4,118,528 assigned to Raybestos Manhattan, both disclosing glass fiber clutch facings. In conclusion, asbestos free brake linings can be made using either semi-metallic friction materials or by replacing the asbestos with a combination of Kevlar aramid fibers and filler. Since semi-metallics have already proven themselves in commercial applications in Europe, and recently in the U.S., and cost less than Kevlar-based friction materials, they will probably be the first choice of U.S. manufacturers when asbestos is eliminated. United States Patent Office 3,434,998 Patented Mar. 25, 1969 1 MODIFIED ORGANIC3,B43A4S,9E98F R IC T IO N M A T E R IA L F.aWt*iigllniaomre AtoldTrihceh BaneaddTixheCoodroproeraEti.oDn,eaanceo, rTproorya,tioVnYo-f, NDeolaDwraarweing. Filed Sept. 13, 1945, See. No. 487,852 l i . Clio.t.24C0l.--C3088c 5I/0K. C99h 3 14. Fltd 69-502Claims ABSTRACT OF THE DISCLOSTRE An organic therein chunks a base of fric tio n se m i-m e ma tallic terial fric tio h n ivin g mod dispersed ifying m a te ria l to serve as the fric tio n c o n tro llin g means. T h e sem i-nu-ldllk m uddier being essential!) high concentra tions o f m cia ! anJ m etal oxide powders in a base o rg ..n i. resin m atrix In order to obtain the ultim ate in fric tio n characteri-- tics p a rtic u la r!) high fric tio n level fo r an o rganic type brake lin in g or fric tio n m ate ria l, it is necessary to add fri.'.c - m odifiers The most com m on o f these fric iio n m odi.icrs arc the cured resinous particles such as that derived fr->m ..,-hew nut 'h e ll liq u id The use o f such i ..-shew re-in p a rti.le v results in increased frictro n .d ef- f r . t i . e n c " o f the base lin in g or fric tio n a l m ate ria l, p a r ti. id...'dv ,,t amne-M o- r e ljtis c !) low tem peratures How - c u - sa.h use h:.s the disadvantage o f decreased la.le tesotar.-c (>r d e c re .i-e j effectiveness at elevated tempera- t rc p - i . r c . o s e r s . ,.nd also the disadvantage o f dc- ceased eTcct vc rc -* over Ion; term n o rm .il si in:-- i- i;- '-C ..1i.-.- !. .i-vi:n.'s , s; ;r, tiq .iite d pedai ptC "U K m u lite At rr ,.t. ;c t:ie tisc o f su .h c u r.d restm-c p a r t i. I . i- in , u-c c: in -iri-a n k m aterials o f abrasive cha-- a . ii'- s t . . - V id rt.iieri.-d- f>>r exam ple alum ina w ill of- ter in .-e sec e ffe .ti-. ene-s and w ill also offer im p-oved tadt- resotanve im proved recovery piu p e rtie s. and iess li.oder t ip e .ia i p rc 's i.tc increase) w ith extended use Su. f: u n > c.i i .i. n ia ic ria ls , h o w c .e r. also hase itehnitc d i-ad va n t. c.-s in in.reused noise ch a ra cte ristic- and ex- .e - i i f w e j-in g . grooving or general d c s tru .lio n o f the rti. t.- g s -rta .e t-srai.c d tu m or d is c ). I' i- an ubje.-' o f the prescnl in ve n tio n to p rovide a sen . n,-.: -Hi. in c t io r m o d ifie r fo r organic base lin in g to p ;o .id v iR .rc js c J fri.tio n ellectivcness at both low and t s - a W t. mp.-t jt u r e ' w ith o u t d isplaying p o o r fade re- 'i> :. -,.e rc .o v e ry . lor e term hatdcning. excessive wear, or -curing It i- another cm ect o f the present in ve n tio n to provide an im proved f r i. tio n m o d ifie r fo r organic base lin in g to m p ti't-J o f a sen t m etallic p article or chunk consisting o ' rn.-ial powder or metalus o xiJc powder m a trix, a , u . u, .onsirtuent and powdered graphite all bound t.-.e r.e: under beat and pressure by a lite r'i> -se u in g ptie n olt. re-tr. binder. The fr i.tio n m odifier o f the present in vention is fo r use w ith an organic base lin in g o f the co n ve ntio n a l type consisting o f a resin base w ith a d d itive o rg a n ic fr ic tio n m o d ifie r' aspestos and the like . The scm i-m etalli. frictio n m odifier or friction con tro llin g m e jn s added to the basic o rganic lining- p re f er j - l y .o m p riscs I 1.- to 20f< by volum e o f the to ta l lin- tng m ate ria l, below 11.- '"< . effectiveness is n o t obtained, iii'ii..- 2 o '- . ptocsssing lim ita tio n s cause the a d d itio n to become uneconom ical A fu n c tio n a l upper lim it is 25C< wherein tnc abrasive content can be expected to have deleterious r i l e d ' w ith respevt to d ru m or disc wear I lie s crm -m cta lli. is to he added as a p a rticle ot chunk st/c greater Ih.n: 2() mesh since the f l i c . I is masked at 2 sm aller p a rticle sizes There is effectively no upper lim it on p a rti.le si/e and the enure 25*3, o f cem i-m etallic may be com prised o f a s in g le la r g e p a n i c l e t-r in s e r t in th e base organic H ow ever, to fa cilita te processing. p re > ferred particle si/e range is fro m plus 2b to m inus mesh The preferred com position o f the te m i-m e ia ilic fn .- lio n m o d ify in g pa rticle is as fo llo w s Constituent Vol., percent O rganic rein b in d e r ______ _________ 20 and riser Cirjphile ................................................................................. 15-25 C eram ic pow der __________________________ 10-25 M e ta l o r m etal oxide p o w d e r ........................... 3 0 -5 0 1* T he processing sequence is to m anufacture a emi- m e ta lli. fr i. tio n m o d ify in g p article by co m b in in g the niclal or n ie l.il oxide powder, ceramic powder and powdered graphite in ar- n rg a n i. resin bindc-t o f the therm osetting phenolic resin type w h i.h is then cured " under heat and pres.ure to fo rm a Mended ng-tJ mass of semi metallic m aterial This m aterial j. then broken in to p a rticle , o f a si/e greater than 2u me h and added to a conventional organic brake b rin g m ix. com prising p re f n . erably I 1.- t,- 2(1'; o f the vo' -n .e of the ttn i.h ed lin in g * m aterial The organic lining m ats'.a! wit;- semi-m etal/ic p a r ii. I t wJdc.! is then processed c u r c j and sr...ped in to a fintsheJ o rg a n i. brake lin in g segment o- Mc-ck The a r p ia '. , n . c ot the bning cat. best be J .s .rm e d ,o m ottle d com p.red to s o r.e n tia n .il linings when t ` e 'cn u -m e ta llic p a rti.le si/e w ut.n the rre le -re d si/e range of p ij- 2 'i ni --u- -r n-e-h s -.ito i-. . e t- m . .on -tittie n t- ar. silla m a -itc m ul'ite . i in o"0 1 .oil >-.id. a:;,' / o . 'm u'- oxide it'.," v\ j i ,*i , , - i j n i i . - ot ,.'.e a 'u r .u -in; Me : 't- .u ilt s i'i.O '. type are e. s | . . a n . >r.. ; a f .,1 n n i i l n e . t i i o u d - - m e : - t, . c , a ` Ic. Prete te-l mct.-.l a anJ f r o U U ill" . . c 'p.-x 1 uon anJ It'll- o \ Me M .e t' ic r n s fr . e it-. deper. J .:. 2 to a r>i'v in. O tent on . 1 " : Sx.il' Ifo n ox.de. f t ; 0 . t\ ^ a sur-'ti . u i to t tuet .is l a ' he t.MTi V C am i.- it wd be nc't-. ,1 - !tk* xi: e. n i. J; T 1* ih i r : m binder :ir.xl the in ' .! 1s no* U x,l IkJ 1. h 1 .) :: ;s. .. ( 1. ne-' d ' * spira ko- the line' Ot Jlv tlf.. '.ion net * een . : .im i.v ar.u m etal ' \iJ e - w h i. ti var. he s. r-'U :-. led tc fie m etal Ckn- ; te n depend, on 1lie abr.i-iv or harJne-s .r.a;a clc ris'ic H ake lining, n i . i i . u ' a . : d n a . c o t d a r . . witf. t'-e above teachings, r e p i c - c - a stgnili.ur: aJ'-.-vce .-.er .or.vrniu'Pal o ir a m . Iinii-g- known in I n pri, r ..'I fieneiallv spe .king the . . d .a n . c is it- rern - o' increased ,,, br.-iri In.tii-n e l l t. hvelii u: dc" varioa- .on.liaor.s of operation ( ompaiison tc-'s aa-.-j! that ir,.rca-cJ etl.c- tiven.s. I. mils! p r o n o u r .c J under se.erc conditions of operjtiur. where .imvention.i! -'rgaii.c limnC' .-re the weakest l o r example, rrakc t.iJe n . l . . . e J hi.-t ter pcialurc. C.,.isc-s! h , trequent n .- > c appli.wti >n ir sh, -I time inter, a - i ie-sened lion- |o .- o ' , k c \ o > ." . <: effectiveness .O'er tade is in .r i .-- c J m ex .e -s c-f 2 * High .peed and tsurnish twear in r etfe.tiven.e-- is im proved by a similar degree While to sonic extent these pu are piv-Jict.ible results of high friction charjctenst.cs of metal and cerjmic particles resistant to deterioration at high temperature, the main significance of the presen; in vention icsides in the fu.t that th-s improvement i- achieved without sacrificing lining wear or x o r in g the h;, mating brake stir/.i.e such as encountered wi!l me:al base or mm e mi. linings. In l a d . test results :,;..vc j c monstt.itej .m increase in lining life ot l ; cater tl..-n 20K contpaimg an organi. with I<'t semi-nv.taliic p.o- tides with a lull organi. of the same type We claim I A niidilicil n.c.iiii. t . . . in .l io n in m i i consist ing of an oi i-.i-ii, i-.isc in t:i-1- Inline m.iten i i .. r ujig 3 4 3,434,91/6 sfrizoemgr1eatetro t2h5a%n 2b0ymvoesluhm: seaoidf asesmcmi-mimectatalllilcicppaarrtitciclelehoafv fwriot hm i n Vthi e lsoize2<>r*a;ngbey o f v oplulum` e20utmain uses m 4 j mm eesl ha,l l usaidpasreiLnna - 2in5g%a,scceoranmstiitcuepnotws dbeyr fvroolmum1e0p-2e5rc*en,t agnrdapmheittealfroormme1t5al gmreatpahlliitce pfarrotmiclel<h-a2vi'n'g;, ascecrojnimstcitupeonwtsdebrv vfroolumme10p-e2r*ce'.nt oxide from 50-50*7 being bound together by an organic resin binder from greater than about 20%. , ' and metal or metal oxide fri .r. to o r : being Kumd to gether by an organic resin hinJc from greater than in 2c.laAimmIodwifhieerdeionrgsaanidicobragsaenifcricretisoinn bminadteerriails aas tchlaeirmmeod about 20% References Cited setting phenolic resin 3. A modified organic base friction material as claimed |,, U N I f l l> S I M Lb r . U L N l S in claim 1 wherein said ceramic powder is a ceramic .VOO-' . s j^ I I I9 M K le in `elected from the group consisting of sillamanite. mullitr. 3.210.MH III. iv n * Bigg' ma4g.nAesiummodoifxieidde,orzgiarncoicniubmase oxide or friction mixtures thereof. lining material as M O R R I S I I f B M A N f Vlf/fiJM L \ t i t U I f . i I claimed in claim I wherein said metal or metal oxide is selet led from the group consisting of iron copper, iron I' K B A R O S . etunli/ir/ f i W l l l l . i r oxide or mixtures thereof 5. A modified org.mi, base friction material comisting UK>-- M> 0 S Cl X K of an organic base friction lining material containing SAE TRANSACTIONS E. J. Manganiello/President M. J. Kittler/Treasurer Joseph Gilbert/Secretary and General Manager PUBLISHED BY j SOCIETY OF AUTOMOTIVE ENGINEERS, INC. / TWO PENNSYLVANIA PLAZA / NEW YORK, N.Y. 10001 710591 Semi-Metallics: A New Type of Friction Material F. William Aldrich Automotive Control Systems Group, The Bendix Corp. THE PAST TWO decades have seen rather dramatic changes in the requirements for frictional elements used in the braking systems of m otor vehicles. Essentially, this shift in require ments has been in the direction of greater heal resistance, greater frictional stability at a higher friction level, reduced noise, and extended durability. In general, the state-of-the-art development of friction materials has kept reasonable pace with these required changes through improved resin binder systems, improved friction modifiers and fillers, and the in creased application of scientific aids for greater uniformity Although friction material development has not been re stricted to the use of organic constituents I00a, a substantial portion of their composition has been organic type materials and they have been, thereby, subject to whatever shortcoming! these materials may have. It is unfortunate that the prime shortcoming of organic type materials, namely their inherent nature to change both their form and properties with tempera ture, is at complete odds with the requirement of frictional materials to maintain maximum uniformity and stability of effectiveness over a wide range of temperatures. In the past, considerable effort has gone into a potential solution to this problem of organic thermal instability in the form of development based on 100/f inorganic materials, namely sintered metallics. However, even these supposed ultimate materials had their shortcomings, perhaps the greatest of which was that they also had too much sensitivity to temperature. At low temperatures they weic ineffective and at high temperatures they were too effective. Their major advantage was low wear in the extreme tem perature ranges of 1000-2000 F, which made them quite successful as aircraft linings. Sintered metallics did have, however, a potential of frictional stability, superior to the organics, if it could be controlled. It became obvious that if the technological advantages of both the organic and sintered metallic friction types could be combined, then a new generation of substantially improved friction mateiials could be obtained. The result of this mar riage i- todays state-of-the-art semimetallic friction materials. Thi! paper will, as a rule, not differentiate between drum biake u:d dis^ brake applications for friction materials, since the basu characteristics remain essentially the same regardless of application. Any difference in the requirements of friction material for these two types is ordinarily only a matter of degree, with disc brakes, for example, generally operating at higher temperature ranges than drum brakes CLASSES OF FRICTION MATERIALS Any discussion of friction materials can be clarified to an extent, by first classifying them along general lines. For pur poses of this paper, let us assume three classes for current mseamteimriaeltsa.llCicl.ass A, Class B, and Class C, with the latter being As a general category. Class A friction materials would be represented by production materials on American made cars over the last 5-10 year period. They would be further categorized as being fundamentally organic in nature, ex cluding. of course, their inorganic asbestos content com omrgoanntioc mleosisnt ohfintdheerms,. oTrghaenyicarreepsirnobfraibc'tyiohnigmhloydliofiaedres,dawndith ABSTRACT-----------------------------------------------------------A new semimetallic type of friction material has been devel oped which offers improved frictional stability and high tem- peiatuie weai resistance. Having minimal organic content, these mateiials avoid the thermal sensitivity to chemical and physical clunpe characteristic of typical friction materials. 20c.`> 2040 natural or synthetic rubbers or elastomers. They frequently also contain small amounts of graphite or other carbon type materials, and possibly small amounts of inorganic wear fillers slouwchinasingororguanndiclimcoenstteonnte,. pAarstiacucllaarslsy, tahneyythwinogulodfbaesguebnerally stantially abrasive nature. Again, as a class they are reasonably quiet, give respectable durability, and under most conditions perform their frictional purpose without distinction. On the demerit side, sizeable increases in temperature raise havoc with their efficiency, and long term use or abuse frequently lowers their effectiveness. They lose friction rapidly ai tem peratures over 450-500 F and start considerable thermal decomposition above 600-650 F. Once having been in this "affective" temperature range, they are seldom like they were beCfolarses. B materials represent a first step major compromise in attem pts to improve the Class A types. As a class, they ordi narily have higher inorganic and lower organic contents, a design factor to improve their thermal stability. They arc most apt to have some degree of abrasive content to help stabilize their frictional properties. Generally, as a class, they have better fade resistance, better recovery, and overall improved frictional and thermal stability. They may give good lining life at higher temperatures (+450 deg), but frequently at the expense of the mating surface which suffers from excessive wear, grooving, or scoring. They are quite apt to be noisy, and in terms of frictional stabilitymay become overly effective with use or abuse, thereby in creasing their noise and reducing their controllability. attTehmepmtsotroe erexctreancttCtlhaessdCesoirrabselempimroeptealrltiicesfrfircotimoneamchateorfiatlhe Class A and Class B types. To gain maximum frictional and thermal stability it minimizes organic content, but it does not ignore it since organics do add desirable properties. It also maximizes inorganic content to gain thermal and frictional stability, but it does not overdo these since it does no! want the potential hazards they offer. WEAR AND FADE RESISTANCE It has previously been noted that one of the shortcomings of organic type materials is their tendency to change form and properties at elevated temperatures. It is this characteristic which contributes substantially to highly accelerated wear as the tem perature goes up. The property of wear is usually considered to be an economic factor only, but to some extent it can also play a part in performance factors. In the case of a drum braked vehicle with duo-servo brakes,moderate differ ences in side-to-side lining temperature or side-to-side lining wear rate can lead to unbalanced friction levels and severe pulls or single brake burn-up. Whether the chicken or the egg comes first is problem atical, but the fundam ental process is the same. In a disc brake, the lack of servo action may prevent pulls for a longer time, but moderate temperatures or wear differences at the higher operating temperature range of the disc brake can result in undesirable and substantial lining life variations, side-to-side and front-to-rear. F. WILLIAM ALDRICH LINING TEMPERATURE-F Tig. 1 - Wear versus temperature characteristics Class A organics do have, as the temperature increases, a temporary degree of self-protection by virtue of their fade properties. By this we mean that increased temperature de creases their effectiveness and their work output, thereby protecting them from further temperature increases and in creased wear rate. However, since fade is generally less on each successive fade condition, this protection is somewhat short lived. Some Class A materials also have such a steep wear versus temperature curve that constant surface renewal minimizes fade and also reduces or eliminates this self-protec tion. Class B organics generally have improved fade resistance and more gradual wear versus temperature curves. This better fade resistance tends to reduce their self-protection. In spite of the better high tem perature wear capability of the Class B types, the organic materials present still cause eventual wear resis tance breakdown, even though it may be at a level 100-150 deg higher than a Class A type. At this point, however, the asbestos fiber is reaching the tem perature range of substantial loss of water of crystallization and is itself deteriorating, actually forming new materials such as olivene. Class C or semimetallic linings have a wear versus temperature curve of considerably less slope than the Class A and Class B organics. The wear versus tem perature curves of Class A, Class B, and Class C materials, as taken from actual constant torque sample dynam om eter tests, are shown in Fig. 1. It will be noticed that the Class C semimetallic is essentially insensi tive to temperature in the 250-650 F tem perature range, while the Class B starts to break at +500 F, and Class A starts to break at +400 F. Also note that up to 500 deg or so the Class B material wears at a rate somewhat greater than either the Class A or Class C types. Because of the minimal organic content of semimetallics. they also have minimal fade. Based on the previous fade = self-pr detrim o e tec nt. t ion In d re isc ali us ty sion the , s one emi wo met uld alli c a ht afsirast con type sid of er se t l his f-p r a o tection which organics seldom have-that of repetitive fade or considerably less tendency to antifade. This is quite evident when one looks at what happens on typical vehicle tests in volving more than one fade, such as SAE J843b. In Fig. 2, it will be noted that for Class A and Class B organics that the second fade shows considerably less friction loss than the SEM I-M ETALLO 2041 r+5] 9 - t 6 ao. TV 7-- % v T1 i i T / i 1 t _ t1 / t i |s > ; soT - mdttkv* KEY MI-MITAUIC L (1 m>rt / \ ) V a Fig 2 - Vehicle fade lest characteristics (5700 lb GVW) ** 0 2L U > --- ' * --' - 810 0 2 4 6 8 IO120 2 4 6 8 10 12 l*-riR 5 T FADE -- I It IRST RECOVERY-- I r -- SECOND FA0E- i ; 0 M 6 8 10 12 (SECOND RTCOVERY-1 CLASSA ORGANIC CLASSO SEMI-MET Fig. 3 Disc pad durability-city traffic test; ('lass A versus Class C first fade, while in the case of semimctallic materials, the second fade may show almost equal friction loss. In the case of semimetallics there is reason to believe that, in addition to the binding action of the resin system there is an inherent mechanical bonding of the metallic components. Such supplementary mechanical bonding, of course, contrib utes substantially to high temperature strength and wear resis tance and can take over at the point the organic binder fails Tcrheearseediswalistho iunsdeicoartdiountyt.hat the mechanical bonding is in Early semi metallic linings showed low temperature traffic wear slightly poorer than Class A materials and more typical oi the Class B types. However, this characteristic has now been mi proved so that on normal city traffic type driving the semi metallic shows appreciably better wear. Fig. 3 illustrates CLASS A ORGANIC CLASS C SEMI-MET 1Ig 4 -1)isc pad wejr ai 100 mph I ull brake dynamometer. Class A versus ( lass C. 10-stop test actual traffic durability test results, generally 350 F max, on four Class A production organic disc pad linings and two Class C semimctallic materials. The C2 material, a more recent development, shows still further gains over the Cl type. At the other end of the duty scale. Fig. 4 illustrates 100 mph wear rate results on a full brake inertia type dynamometer using these same materials. Again, the more recent C2 material shows improvement over the C l. FRICTION Class A friction materials as a rule have the highest friction when cold and the lowest friction when hot. Class B materials are generally somewhat lower friction cold and higher friction hot compared to Class A types The senumetallic materials :042 have substantially different friction characteristics, in that they tend to increase with friction with both increased tem perature and increased surface speed. This characteristic has a distinct advantage for high speed effectiveness. Historically, high speed effectiveness of organic materials has been a problem. Since increased surface speed means increased tneemssp, earsatthueres,pteheedoirngcarneiacssedh,avfreequsuueanltllyy srheoqwuinripnogosroemr eefefexctteinve sive power assist to maintain reasonable pedal efforts. In contrast to this, the semimetallic materials have temperature/ speed characteristics which tend to reduce pedal effort and stopping distances from high speeds. Also, in contrast to previous full metallic linings (sintered materials), the low speed cold effectiveness is greatly improved. It is acknowl edged that there is still some room for additional improve ment of this characteristic with semimetallics, but to date, there has been no serious deficiency in this area. Actual tests have been made in the subzero tem peratures of a Canadian wiSnttaebr.ility of friction throughout the life of the lining has also been a problem with organic types. Their general charac teristics of high initial friction have frequently led to initial vehicle braking instability, and their characteristic of friction drop or loss after moderate abuse (fade) or long term light usage has frequently initiated complaints of ineffectiveness. In addition, their characteristic of friction " peaking" vsith severe use. particularly in the case of Class B materials, has led to vehicle braking stability and controllability problems. By virtue of their minimum organic content, semimetallic materi als are much more frrctionally stable over a wider range of use or abuse. NOISE This nonfunctional characteristic of brake systems and friction materials has kept industry engineers "hopping" for years. The friction materials engineer may be reluctant to agree that noises are always the linings fault, but he docs have to agree that there are linings more or less prone to producing noise. Brake design or lining attachment not considered, class organics generally tend to produce their maximum of audible response in their cold or warming condition. Class B types usually duplicate the Class A in this respect, and supplement this with additional noise when warm or hot. The effect of this characteristic is that the driver of the vehicle has the greatest odds of obtaining noise under the conditions under which he does the majority of his driving. Again, semimetallic materials tend to reverse these charac teristics. They tend to produce minimum noise cold or warming and have their maximum noise while hot (for exam ple, above 350 F). On this basis then, the driver is most apt to hear noise not under normal driving conditions, but rather during the less frequent or abnormal conditions. COMPRESSIBILITY In the disc brake, the compressibility of the lining material is a significant contributor to excessive fluid displacement. F. WILLIAM ALDRICH Fig 5 - Disc pad swell and crush comparison (at 5000 psi constant stress) The actual compression of the pad material is a function of both the inherent compressiblity of the pad and line pressure required, which is a function of the materials fade resistance. This allows us to approach the compression problem from both directions; reduce inherent compressibility and/or reduce line pressures required (improve fade). Class A materials, because of their high organic content which tends to create inherent compressibility, and also to create fade, generally offer the maximum in fluid displace ment. Class B materials with less organic content tend to offer substantial improvement in this area. Class C semi metallic materials with still less organic content and improved fade resistance, have a potential of substantially greater im provement in reducing fluid displacement. The accurate comparison of compressibility of various friction materials under controlled laboratory conditions is difficult, due to their variable initial swell characteristics on heating. One procedure which has been used involves main taining a constant 5000 psi load on the sample and plotting, swelling, or compression versus temperature up to 800 F (Fig. 5). It will be noted that the Class A organic with high elastomer content had an initial and immediate compression prior to its showing any degree of swell. All the pad materials displayed the same basic characteristics; that is, they showed swell under initial heating-up to some point in spite of the preload. It will be noted that the Class A organic with high elastomer content actually crushed at a pad temperature below 400 F, while a similar material with low elastomer content showed improvement, but still crushed at less than 550 F. The Class B material started to compress at 550 F and failed at less than 700 F, while the semimetallic material started to compress at 650 deg but would not crush at the 800 deg temperature limit of the oven used. OTHER CHARACTERISTICS In the early stages of development, the increased heat conductivity of a metallic type friction material, particularly SEMI-METALLI CS for disc pad use,and its effect of fluid boil was considered a potential problem. The use of a two layer, organic backed semimetallic pad with the organic acting as a heat dam was itnesdtiscawteitdh.ouHtoswuecvheirn, smulaantyionacftauialledvethoicplreoadnudcedyflnuaidmboomile.ter Controlled tests did indicate fluid temperatures 60-80 deg higher with semimetallics than with organic. A practical consideration, however, is that under extreme tem perature conditions or use, the wear of organic materials can be so great as to bring the actual shoe in contact with the rotor, a most critical set of conditions. This possibility is recognized by SAE and certain vehicle manufacturers who appraise their designs for fluid boil in the bare shoe condition. Compared to organic linings, semimetallic materials have relatively low coefficients of friction against the backing plate or shoe, and a "norm al" riveted attachm ent can result in some shift or loosening and potential cracking. For this reason a roughened or grit blasted shoe surface is recom mended, preferably combined with a tapered rivet head. Alternatives to this are a higher cost organic backed pad or integrally molded or bond-molded assembly. Although the chemical composition of semimetallics varies 2043 considerably from that of normal organic friction materials, their mating surface compatibility characteristics are extremely sthaetiisrfapcetrofroyr.maCnocme paanrdedwteoaroltehveerl,mthaeteyriaarles eevxetrnemapeplryokacinhdintgo mroatotirngmseutarfllaucregsyanodr fgineinsehr.allIyn rtehqeuciraesenoofshpeeacviayl ddurutymdorur m brakes for large trucks, they virtually eliminate drum spotting and heat checking typical of most materials in use. SUMMARY A new type of friction material of improved frictional and thermal stability has been developed. This new type of fric tion material, when compared to current conventional types has the following characteristics: 1. Improved wear resistance, particularly at high tem pera ture. 2. Improved fade resistance. 3. Improved high speed effectiveness 4. Impioved frictional stability. 5. Minimal noise. 6. Excellent mating surface compatibility. " United States Patent m Aldrich [54] SFTREICETLIOANNDMCAETLELRUIALLOSREEFINIBFEORRSCED WITH [75] Inventor Francis William Aldrich, Troy, N Y [73] Assignee The Beadix Corporation, Southfield, Mich. [21] Appl. No. 112,541 [22] Filed Jal. 5, 1977 [51] Int. CL- ................................................... OOCL 1/02 [52] U.S. Cl.......................................... 260/17.2; 74/190; 188/218BBR;; 216808//125714 RC;L1;8286/205/318;A2; 6206/04/2171.74; 260/42 18 [58] Field of Search ................................... 260/17.2, 38 [56] Refereocea Cited U S PATENT DOCUMENTS .V684.0e2 8/1972 Johnson ... 188/251 R HD 4,119,591 [45] Oct. 10, 1978 3,04,701 4/1974 Bognar ................................. 240/17.2 33,.193225,.214118 191/1/1997745 RBhaereke.r...e.t...a..i...................................................... 226600/1/3712 3,939,194 5/1976 Adelmann ...................... 188/231 A Primary Examiner--Edward M. Woodberry Attorney, Agent, or Firm--Leo H. McCormick, Jr.; Ken C. Decker [57] ABSTRACT An asbestos free organic base friction material for use as friction lining of a brake. A combination of fibers telected from a group consisting of steel, cellulose, glass mineral and rayon fibers and a thermosetting resin binder are combined with cashew nut particles, elasto meric modifiers and inorganic modifiers to produce an organic base friction material having s substantial stable ocofetfhfeicibernatkeo.f friction over the normal operating range 10 Claims, 25 Drawing Figures 250 300 400 500 600 700 U.S. Patent o. io, i978 sheet i of5 4,119,591 FIG. I FIG. 2 FIG. 3 FIG. 5 FIG. 4 FIG. 6 U.S. Patent oct. 10,1978 Sheet 2 of 5 4,119,591 FIG. 7 FIG. II FIG. 8 F IG .10 FIG. 12 U.S. Patent oct. io, 1978 sheet 3 of5 4,119,591 FIG. 13 FIG. 14 F IG .15 FIG. 16 FIG .17 FIG. 18 U.S. Patent Oct. IO, 1978 Sheet 4 of 5 4,119,591 FIG.21 FIG. 23 FIG. 2 2 FIG. 24 1 4,119, diapuned throughout a friction lining provide sufficient FRICTSTIOENELMAANTDERCIEALLLRUELIONSFEOFRICBEEDRSWITH stitornentgothwtitohastllaonwd adyfrniacmtioicn lloinaidnignmp awdiethoofutthedectoemriporoasti BACKGROUND OF THE INVENTION j ingItuinsdthererneofromreatlhoepeorbajteicntgocfotnhdisitiinonves.ntion to provide Organic friction material compoaitions currently uaed an asbestos free organic friction lining with sufficient in clutch and brake linings of vehicles must be capable of withstanding severe operating temperatures and dy structural strength to repeatedly withstand dynamic loads without deteriorating when used in a brake lining namic pressures experienced during tions- To prevent a deterioration in repeated applica performance and 10 It n another object of this invention to provide an organic friction material with a foundation material physical degradation during an application, the lininp are reinfoced by asbestos fibers randomly dsspuned made up of a combination of at least 3 percent steel fiber and 3 percent cellulose fiber. The steel and cellulose ethvridoeungcheouint daicarteessinthmataathsbs.esHtoos wliebveersr,carnecceanut semheedaicltahl fibers being disputed throughout tbe friction material to uniformly distribute forces exerted on s brake lining hazards of the lungs fibers of the type used in persons exposed to asbestos in the manufacture of clutch and IS and thereby prevent degradation thereof peated dynamic brake engagements. during re brake lining. The health hazard is caused by the polution of the surrounding environment with small parti It is another object of this invention for providing an organic friction material with a base material of steel cles of asbestos during the mixing of the friction compo sition in a manufacturing facility. 20 fiber and cellulose fiber to establish a substantially uni form wear characteristic over the operating range of In an effort to reduce the environment contamination by the asbestos fiber and thereby continue manufactur friction lining. These and other objects should be apparent from isnlugrraysbpersotocesssbaisseddisocrlogsaendicinfrUic.tSio.npalitnenintgsa,ppalicwaatitoenr reading this specification and viewing the drawing. Ser. No. 754,477 has been evaluated. The water slurry 25 cwainthboeuttracnosnmtaimtteindatthinrgougthheoustuarrmouannduifnagctuernivnigrofnamcileintyt BRIEF DESCRIPTION OF THE DRAWING FIGS 1-24 of the drawing are graphs comparing the with asbestos fibers. However, before the friction mate rial can be cured, the water in the sluiry must be re wear characteristics of the non-asbestos organic friction material composition made according to this invention moved in order to has essentially the be assured that same operating any resulting lining characteristics as a 30 with a FIG typical asbestos organic friction lining, and 25 is a table illustrating non-asbestos friction lining made from a dry mix. material composition made according to this invention hazInaradnsoitnhetrheattmemanputfatoctruerdeuocfe ltihneinogcscuuphaatisonbaelenhesaultgh DETAILED DESCRIPTION OF THE INVENTION fgiebsetresd. that the asbestos fiber be replaced with glass 35 In order to evaluate the non-asbestos fnction materia! U.S. Pat. No. 3,967,037 discloses several lining com positions utilizing fiber glass. From experimentation it compositions disclosed by this invention, typical asbes tos base fnction material compositions were used as s has been determined that such lining compositions acceptable, however, in admixing the ingredients are the 40 standard to determine the wear rate and coefficient of friction characteristics of the non-asbestos base friction fiber glass tends to ball and thereby reduce the continu ity of the friction material. In addition, when fiber glass material when uaed in t brake. FIG 25 illustrates the relationships of the various base friction materials are mated with a steel brake rotor or drum, an unacceptable wear condition occurs. combinations of the fibers substituted for asbestos as disclosed by this invention. U.S Pat. composition No. 3,896,075 discloses another wherein the asbestos in an organic friction lining is 45 The ingredients in the asbestos tion material formulations were apnrdocneosrs.e-dasbinestotosbrfnakce replaced with basalt fibers Because of the process re friction lining in the following manner as described in quired to reduce the mineral basalt into a fiber state, the use of such friction composition to date has not received detail for the base line asbestos material composition A. The asbestos fiber, dry phenolic resin, equal pans of ogpaemne afrciccetpiotnanmceataesriaalss.ubstitute for asbestos based or- 50 cashew barytes nut powder and synthetic were mixed together until a rubber scrap and homogeneous mix Later as disclosed in U.S. Pat. No. 4,019,912 the rein ture was achieved. Thereafter, the mixture was placed afocrhciienvgedoftthhrtosutgrhucttuhreeuosfeaorfescualrtbinognfrfiibcteirosn. lHinoinwgevwears, in a mold and compacted into a briquette. The briquette was then transferred to a press and compressed by a the pyrolysis step required to reduce the rayon or celluloae fiber to a carbon fiber would destroy the elastomers 55 force of about 5,000 pounds per square inch while the temperature of the briquette was raised to about 250* F atinodnsi.norganic fillers found in organic friction composi tfelomwpetrhartouurge.hoTuhteth2e50m* ixFt.ucraeuasneds ethsteabplhisehnoalimc artariixnfotor SUMMARY OF THE INVENTION ^ holding the other ingredients in a fixed position. The briqaette was then transferred to a coring oven having I have developed so organic friction material compo sition consisting of an asbestos free foundation material, a temperature of about 500* F. to further set the main. The briquette was then ground to a specific size corre organic and inorganic friction modifiers retained in a matrix of a thermosetting ream. The asbestos free foun spplaocneddinogn atodysnabmraokme ePter* anTdhfirsombrtabkee tepsat*d pwerafsortmheedn dfiabteironanmda5tepriearlciennctlucdelelsualossaemfiibneirmaunmd oofth3eprefribceenrst ssutecehl 65 thereon it was established that the composition Formula A had an average coefficient of friction of 0 36 at 450* as carbon, mineral and fiber glass. The steel and cellu lose fibers when randomly orientated and uniformly F and a wear rate as illustrated by base line 20 shown in FIGS 1-9, 20 and 21 3 4,119,591 4 noInn-aosrbdeesrtotso efrsitcatbiolinshmabtreoriaadlercobmaspeofsoitrioenvsa,luaatisnegcotnhde tioInnNano.at5teamspiltlutostsrmateodotbhyoulitnteh3e0wienaFr IrGat.e 5o,facofmillperosoif acsobmepstoousnfdreicdt.ioInn Fmoartmeruialla iBdetnhteifileadrgeasaFmoorumnut loafBasbweass 53%to bpyrovdoulcuemceoomfpcoasribtoionnwNaos.a6ddinedTatoblceom1 pTohseitcioonmNpoo ttoiosninpoFwordmerualandAaisfirlleeprlaocfegdrabpyhiatdedpitairotnicallescatoshperwodfuricce 5 swithioenn Nevoa.lu6awteads imn atdhee idnytonaambormakeetefrritcetsiot,nanlinainvgeraangde aFobrrmakuelalBinainbgr.akTehepadavmeraadgeefrcoomef,fuicsiienngtthoef sfarmicetiodnynoaf caonedffaiciwenetarofraftreicitlilounstroafte0d.28byatli4n5e0*32FinwFaIsGobt6aiwneads mtoobmee0te.3r5teasntdasthuesewdetaorervaateluaisteilFluosrtmratuelda Abywliansef2o1unidn 10 proInduacefudr.ther attempt to broaden the base for the inor FIUGpSo.n10in-1it9iaalnedva2l2u-a2t4ion of the non-asbestos friction gFaInGi.c 2fi5l,lewr amsopdriofideursc,eadcoInmpcoomsitpioonsitNioon. N7 oas. s7haowmniniin mfroamteritahles mitibxetucaremleefetvtihdeenret mthaaitnitnhge rinemgroevdaielnotfsainsbaesdtroys mbausmic osfte3e%l abnyd vcoellulumloesoeffriobtetrencoamtopnoeswitiaosna.ddWehdetno tthhee cTrhuemrebfloyre,stiatlewadsunreincegssathrye tobraidqduepttaen foofrmthiengphesntaogliec. 15 bdryankaemloinminegterofancdomanpoasvietiroangeNcoo.ef7ficwieanst toesftefrdictoinonthoef orersdienratsoaplrioqduuidcetoa aclol mthpeosniotino-nascbaepstaobslecoomf pboeisnitgiohnanin 0tr.a3t2edatb4y50li*neF3. 4wiansFoibgt.ai7newdasanacdhaievweedar rate as illus dleTdhaesnaonp-raesfboersmtoesdfbrincqtiuoenttme.ateria) composition No 1 fricIntioonrdmerattoeriiamlpwrohviteintghewwaesasrerlaetceteodf tahsethneoni-naosrbgeasntoics sahnodwcnelilnulFoIsGe .T2ib5erwhweerreeinsaubcsotmitubtiendatifoonr othfesteaeslbefsibtoesr 20 mprooddiuficeerd, anWdhceonmthpeosdityionnamNoom. e8teshrotewsnt winasFIrGun 2fo5rwthaes afinbderfowramsefdorimntuolaatbedrakme tlhineinsagmWe mheannntheer adsynFaomrmomuleateAr cboraekffeicliiennintgofmfandcetifornomofco0m.30poasliti4o5n0*NFo 8w.aasnoabvtearinagede taegsetscoweefrfeicipeenrtfoorfmfreicdt,iocnom0 p1o4saitti4o5n0`NFo a1ndhaadwaenaravraetre 25 apnrodduacwedear rale illustrated by line 36 in FIG 8 was irlaltuestarpapterdoabcyhelisneth2a2t ionfFthIeGas1beAstsoscamnabteerisaeleno,f tFhoermweualar comInpaonsiatitotenmNpot to8 itmhepfrnocvteiotnhepcroodefufciciniegntmoaftefnnacltikornyoo-f a. Iwnhoicrhdeirs ctourersetnatbllyisahccaegprteodupbyofthineovrgeahnicicle fiinlldeursstrayc- lsihteowwnasinadFdIGed t2h5erWetohetno tphreodburackeecloinminpgosoitfiocnomNpoosi9 cweapsabsluebsftoirtuutesde ifnora tnhoen-washbiteisntgosoffriccotimonpomsiatitoennalN. otalc1 30 ativoenraNgeo. c9oewffaiscieenvtaluoaftefndcmtiotnheofdy0n3a7maotm4e5t0e*r tFest,waans ahnshdedcomThpeosdiytinoanmNomo et2ershteoswt nforinthFeIbGrak2e5liwniansgemstaadhe from composition No 2 indicated than an average coef ys owbatsaipnreodduancdeda wear Composition No rale illustrated by line 38 in FIG. 9 10 shown in FIG 25 includes the iflilcuiesntrtatoefdfrbiyctilionne o2f40in30FIaGt 4520c'oFuldanbde eaxwpeecatiedraftreomas soafmtheetyaspbeesintogsrefdnicetniotsn ams aFtoerrimalulTaoBeswtaitbhlisthheberxocaedpbtiaosne thiBs eccoamuspeosoiftitohne availability of barytes and its low cost, ffonrcttihoen forifcttihoennmona-taesnbaelsatonsdmimatpernoavleththeecceolleuflfoicsieenfitboerf aopseednes of compositions including barytes were devel 4i cwoams proespiltaiocnedNwoit1h0gwlaasssevfiableurateWdhbeynthtehedybnraakmeomlineitnegr latAeds sWhohwenn itnheFIbGrak2e5. lcinoimngpomsiatidoen fNroom3cwomaspofosritmioun twesats, oanbtaavineerdagaencdoeaffwiceieanrtraotfefnilclutisotnratoefd0b3y5 alitne45400` Fin eNnot o3f wfraicstieovnaloufa0te.3d 1bayt the 450 'dyFnawmasomobettaeirnetedstaandcoaeuf fici rai 45 FthIaGt w1h0ilweagslaascshifeibveerdwFhreonmadthdiesdtetsot intowna-assdbeetseiroms ifnnecd ratEeviellnusttrhaotuedghbythleinew2e6arinraFtIeGof3cwoamspporsoitdiouncedNo 3 toifonfnmctaiotenn,ahl ocwomevpeors,ittihoensw, deaoresraintecriesaaslesothienccoreeafsfiecdient citouwladsbfeeletxtpheacttethdetocobeeffbiceitetenrt tohfanfritchtaiotnofcoFuolrdmbuelaimA. waTshdeerveaefltoepre,dcowmitphoswitoioond fNloour 1a1ddshedowinn pilnacFeIGof th25e oprrofvibeedr mthartoeurigahl tThheroadudgihtioenxpoefnmeiethnetartiaondifitfewreanstdfeitlleerr 50 oglfacsosmfibpeorsiotifocnomNpoos1i1tiownasNeov.a1lu0aWtedhethnrtohuegbhrathkee dliynninag mthiannedcethllautlogsleassfibfiebre.rThhaesraefhoirgeh,erglcaosesfffiicbieerntwoafsfnsucbtisotni ombotamineetedr atensdt,aawcoeaerffricaiteenatsoifllfunsctrtaiotend0b3y7liante45402*inFFwIGas. tsuhtoewdnfionr FtIhGe c2e5llwulaosseprofidbuecreda.ndWhcoenmtphoesibtiroankeNlioning4 ss c11ellwualossperotydpuecefdibeFrsrowmhtehnisctoemstbninwedaswdietthersmteienledfibthearst oetfecromtespto,saiticoonefNfioc.ie4nwt aosftefrsitcetdiotnhr0o.u3g5hatth4e5d0y`naFmowmas pternoadlucceodmpaomsiotiroensathtiasnfacwtohreyn naonti-nagsbleesftiobserfnmctaitoennaml ais 4prowdausceadchainevdead.wUeanrforartteunilaltuesltyr,atewditbhytlhiinse a2m8 oinunFtIGof useTdh.ereafter, an attempt was made to establish the golfaassrofitboerr oinr cdorummpobsriatikoen cNouo.ld4bseurefxapceecpteodlish or wear 60 owphteimnuumsedliamsitthseffoorunsdteaetli,oncemllautleorsiea,l .aonrda noothne-arsbfeibsteorss anTdhceerlelufloorsee, ftihbeeraamddoeudnttoofprgoldasusceficrboemrpwosaistiornedNuoce. d5 fFnIcGtion25mwataesriaplr.oTdhuuces,d coImn pcoosmitipoonsitNioon. 1N2osho1w2.nthine bshyocwonmipnoFsiItGio.n25NoW. 5hewnatsheevraelsuualttiendgibnrtahkeedliynninagmmomadee 65 fviobleurmeWohfencetlhluelobsreakfeibelrinwinsgs mdoadueblefrothmat coofmtphoesisttieoenl aterwteesatr, arcaoteeffiilcliuesntrtaotefd0.3b2yatl4in5e0*3F0. winas FobIGtaine5d wanads cNooeff1ic2iewnat<oefvaflnucattieodn tohfro0u.3g5h atthe45d0y*naFm. owmaseteorbttaeisnt,eda achieved. and a wear rate as illustrated by line 44 m FIG 12 was U .S . Patent Oct. 10, 1978 Sheet 5 of 5 4,119,591 ORGANIC FRI CTI ON MATERI AL COMPOSI TI ON "TYPICAL ASBESTOS FRICTION MATERIAL FORMULAS N O N --A S B E S T O S F R IC T IO N M A T E R I AL FO R M U LA S IN G R E D IE N T S A ASBESTOS FIBER 52 B i 2 3 4 5 6 7 8 9 10 II 12 13 14 15 16 17 18 19 2 0 21 2 2 2 3 2 4 43 STEEL FIBER 5 5 8 8 8 8 8 5 5 8 8 8 8 8 8 8 8 8 15 5 8 8 8 8 CELLULOSE FIBER 7 7 10 7 7 10 10 10 16 10 13 13 13 13 13 25 15 GLASS FIBER 533 10 3 WOOD FLOUR PHENOLIC DRY 25 R E S IN L IQ U ID (o) OMROGDAIFNIIECR S Z Z (b) INORGANIC 1 M ODIFIERS 10 16 15 15 17 2 0 2 0 2 0 2 0 17 2 0 2 0 18 2 0 25 2 0 2 0 2 0 2 0 2 0 2 0 20 2 0 17 20 18 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 10 34 0 0 0 0 0 0 0 0 <2t 0 ~W 4 fit 0 0 st 0 0 0 0 0 # 47 4 7 45 4 7 45 42 45 43 4 0 4 5 4 8 4 0 4 0 4 0 4 0 4 0 4 0 4 0 45 45 4 5 4 0 17 25 7 201) 2(21) 2(33) (145) (132) (15) 1(T2) (20) (293) f1o2) 0II0 9II?) 0132) 142) O14) (14) 14 II4 01*5) 2G5WG2O2 t3tt0) t2tw5 (2344) WCASHEW NUT POWOER, NATURAL RUBBER, SYNTHETIC RUBBER SCRAP, LATEX, CRUDE MOLASSES, ASPHALTIC BASE MATERIAL, ETC. (NBARYTES, W HITING, TALC, ROTTEN STONE. CARBON PARTICLES, QRAPHYTE PARTICLES, CRYOLITE, IRON OXIDE, COPPER POWDER* W O LLA S TO N ITE , K R Y O L IT E . ETC.________________________________________________________________ 4 ALL PERCENTAGES 6 IV E N IN. VOLUME OF TO TAL C O M P O S ITIO N ___________________________________ 0 AT L E A S T 2 9 % OF WHICH IS CASHEW NUT POWDERS (D A T LEAST 16% OF WHICH IS W H ITIN G (13) AT L E A S T 12% OF WHICH IS BARYTES (2) AT LEAST 16% OF WHICH IS TALC (3)A T L E A S T 10% OF WHICH IS B AR YTES (4) AT LE A S T 15% OF WHICH IS B AR YTES (g)A T L E A S T 12% OF WHICH IS BARYTES 6) AT L E A S T 3 % OF WHICH IS CARBON 7)AT LEAST 3 % OF WHICH 13 R O T T E N STONE (14) AT (15) AT (16) AT (17) AT (18) AT (19) AT LEAST LEAST LEAST LEAST LEAST LEAST 3% 3% 3% 3% 11% 5% OF WHICH IS CR YO LITE OF WHICH IS ROTTEN STONE OF WHICH IS IRON OXIDE OF WHICH IS COPPER POWDER OF WHICH IS BAR YTES OF WHICH IS WOLLASTONE 6 ) AT LEAST 11% OF WHICH IS W H ITIN G 9 ) AT LEAST 3 % OF WHICH IS KRYO LITE (IO)AT LEAST 12% OF WHICH IS BARYTES (IO a t LEAST 11% OF WHICH IS BARYTES (12)AT LEAST 11% OF WHICH IS BARYTES FIG. (2 0 ) ATLEAST (21) AT LEAST (22) AT LEAST (2 3 )AT LEAST 25(24)AT LEAST 5% OF WHICH IS CARBON 12% OF WHICH IS BARYTES 10% OF WHICH IS SILANIZED MINERAL FIBER 2 5 % OF WHICH IS BARYTES 10% OF WHICH IS CARBON 6 psproodnguyceadndUthnefroerftournea,teitlyw,ascodmetperomsiitnioend thNaot th1e2cewllaus sptarrutcictulersalcasntrebnegrtehpliancetdhewiftrhicctiaornbolninfinibge,rst.he carbon losTehfeibreearfstehro,utlhdebceelrleudlousceedf.iber of composition No 12 ganInicafrfiucrttihoenr matotedmifipetrst,othesetavbolilsuhmaetbriacsepeforcretnhteagienoorf wFIaGs re2d5u. cAedbrtaokeprloindiuncgemcaodmepforosimtiocnomNpoo. s1it3iosnhoNwon. 1in3 3 tpheercsetenetal gfiebeorfwbaasryintecsrewasaesdeasntadbalismhiendimautm12v%olutomeptrnoc cwoaesffeivciaelnutatoefdfinncttihoendoyfn0a.m32omate4te5r0t'eFst.,ahnaddaanwaevaerrraagtee dburackeecloinminpgosmitaiodne fNroom. 2c1omshpoowsitnioinn" NFIoG. 2125w.aWs ehveanlus awsasillnuosttrastpeodngbyy, lhinoew4e6veirn, FitIsGhou1l3d. Tbehinsocteodmpthoastititohne 10 afrtiecdtiotnhroofu0g.h32thate4d5y0n' aFmwomasetoebrtatiensetdaancdoeaffwiceiaerntraotef coTefhfiecrieefnotreo,fifnnoctridoenr wtoaisncreredausceedth.e coefficient of fric illuTshtrearteeadftbeyr, ltihnee 6st2eeinl fFibige.r 2w1aws amsapinrotadiunceedd.at 8% by tcioomn,pcorsyitoilointeNwoa.s1a4dsdheodwtno itnheFIcGom. 2p5oswitaiosnprNodo.uc1e3da.nAd dvuocluemceomanpdossiitliaonnizNedo.m2i2nesrhaol wfinbeirnwFaIsGa.d2d5e.dAtobrparkoe batreadketlhirnoinugghmathdee fdroymnamcoommpeotseirtiotenstNoh.ad14awnasaveevraalgue- 13 lainndinwg hmenadeevaflruoamtedcoimn tphoesidtiyonnamNoome2t2erwtaesst parcoodeufcfeicdi, ciloluesfftricaiteendt boyf flirniceti4o5n ionfF0I.3G7. at 450' 14. F. and a wear rate eilnlutsotrfatferdictbioynlinoef 604.28in aFtIG450"22Fw.,aasnpdroduwceeadr. rate as poSsiitniocne tNheow1e4arwraastemanudchcoimeffpircoievnetdoofvfreirctFioonrmofuclaomB, 20 ranFgreomoftshteeeflofriebgeorinsghotueladt ibteshmoauilndtabieneedvibdeetnwtetehnat3thtoe tshuebsotirtguatinoinc omfordoitftieenr sbtaosnee wfoars thexepcarnydoelditethtoropurgohduthcee t1h5evooplutimmeumperracnegnet oofftcheelltuoltoaslemanixdtuorteheHr ofiwbeervsehr,adsinncoet clionminpgosmitiaodne Noof c1o5msphooswitnionin FNIoG. 1255 wWashenevaalubaratekde bineeFnIeGstab25lishweads, tdheevriesfeodr.e,IncocmopmopsoitsioitnionNoN. o2.3 s2h3owthne tfhnrconuognhotfh0d3y3naamt 4o5m0e'tFer twesats, oanbtaavineerdagaendcoaefwfiecaiernrtaotef 25 cceelnltuloofsethefibtoertawl vasoliunmcreetanscedpetroceanmtaagxeimofumtheocfo2m5ppoesri illuCsotrmatpeodsibtiyonlinNe o50 1i4n wFIaGs fu1r5thwearsepxrpoadnudceedd.through trieodnucwehdilteoat15th%e sWamheentima ebrtahkeeclaisnhinewg mnuadt epofrwodmercowmas tchoemspuobssittiitountioNnoof1i6rosnhooxwidneifnorFtIhGe.c2ry5olWiteheton parobdruackee 30 pteorsitteiostn, sNoco. e2f3fiwciaesntevoaflfuraictetidonthorofu0g.4h5thaet 4dWyn'amF owmaes tlihnrionugghmtahdeedyonfamcoommpeotseirtiolenst,Naocoe1f6ficwieanst oefvfarliucatitoedn 2o3btawinasedparondduacwede.arArsatseeeans,ilcluosmtrpaotesditiboynliNneo663malFmIoGst otrfa0ted34 at 4li5n0e'5F2 iwnaFsIGobta1i6newdaasnpdroadwuceeadr rate as illus mlinaitncgheasndthecowuledarbreaateccfeoprtceudrrbeyntmlyosatccveephtiacblelemaasnbeusftaocs thrCooumghbpyothsietisounbstNitoution14ofwcaosppestrilpl owfudrtehrefroretxhpeacnrdyeod 35 tiundreursstrwyitwhoouultdexbteenadbeled tqoumaliefeitcatthioenFteedsetirnagl CTlheuans, .tAhier slihteowanndingFlaIGss f2i5berA tborapkreodliuncineg cmoamdpeofsriotimoncoNmopos1i7 atinmde Hseetaflothr cSotmanpdliaarndcse.of 1975 within the prescribed ttieosnt hNaod a1c7owefhfeicnieenvtaolufaftnecdtiothnrooufg0h.34theatd4y5n0a"mFomanedtear 40 anTotohesrubcsotmanptoiastietiotnheNroe.su2l4ts sohfowconmipnosFitIiGon 2N5ow2a3s weCaromraptoesaitsioinllusNtroated14bywlianse 5s4tilml FfuIrGther17.expanded pwrheipleariendcrbeyasrinedgutchiengretshine cpoenrcteennttaagnedosfucbesltliutulotisnegfcibaerr ttchropurogdhucthee caodmdiptoiosnitioofnfiNbeor g1l8assshotowtnheinbaFsIeGma2t5eriaAl bafotneri,nwphoewndaefrrifcotrimonfobrriangpomrtaiodne forfomthecobmarpyotessitiTonheNroe buraatekde tlhinrionuggmh athdee dfryonmamcoommeptoesrittieosnt hNado a1c8owefhfiecnieenvtaol-f 45 2fi4ciwenatsoefvafrluicattieodn tohfro0u.2g8hatthe45d0y'nFamwomaseotebrtatienset,daacnodefa fbnyctliinoen 5o6f iCn.3F7IaGi 41580' F and a wear rate as illustrated wduecaerdrate as illustrated by line 68 in FIG 24 was pro andIncoelrlduelorsteofeibsetarbilnishtherenlaotnio-anssbheipstobsetfwnceteinonstmeealtefnibaelr, 50 thaFtrowmhiltehestefoelreagnodincgelcloumlopseosfiitbioenr spritodwuacsedaentearmccienpedt stnmtocnelalunldosceofmibpeorswitaiosnelNimoina1t6edshfroowmnthine bFaIsGic c2o5mwpaos atobgleethneorn-wasitbhesitnoosrgfanncitciomn omdiafiteerrsia, l,whwichhencacnominbcilnuedde pwriothduacnedadeInquaanteatcteomefpfitciteonptroofvifdriectcioomn,paotsilteiaosnt N5%o. b1y9 grilaalssw, imthinaersaulbasntdanctaiarblloynufnibifeorrsmprwodeuacreraatefritchtiroonugmhaotuet vAolburmakeeoflinWinagllamstaodneitefrowmascaodmdepdostiotiothneNcoom1p9oswitihoenn 55 theI oclpaeimra.ting range of most brake linings eevntaloufatfendcttihornouogfh0th3e2 dayt n4a5m0'omF.etaenrdteastw, heaadr aractoeefilfliucsi lin1in. g coAnnsisotringganoicf afrmicitxiotunremoafterial for use as a fnction traAtesdsebeynliinneFI5G5 .in19F,ItGhe. w19e.ar rate for composition No. 60 8-5fi0b%ersbsyelevcoteludmfreomofaagrcooumpbcinoantmiosntinogfonfofnib-aesrbgelaatsoss, s1t9eewl afsibenrotinascogmopoodsiatsioansbNeost.o1s9Fwoarms rueldauBcedThanuds, ctahre manidneartallefaisbter5,%atblyeavstol3u%meboyfvcoellulumloeseoffisbteeresl, fit rs, 2b0onaspashrtoicwlens iwn eFrIeGa.d2d5e.dWtohepnroadubcraekceolminpinogsitmioandeNoo.f 51-23-53%5%bbyyvvoolulummeeoof fcathsheremwonaeutttipnagrtpichleens:olic resin, cmoommpeotseirtitoenst,Naoc. o2e0ffiwciaesntevoaflfunactetidonthorof u0.g3h7 tahte45d0y'nFa- 65 31-02-05%5%boyyvvoolulummeeooffeilnaosrtgoamneicricmmodoidfiiefiresr,ss;aaidndthermo pwraosduocbetadi.neIdn asnodmaewaepaprlircaatetioinllsustinratoerddebry ltionea6c0hiwevaes sfoetrtminga pmhaetnrioxlicforreshionldbinegingsairdespnoonn-saivsbeesttooshefiabtertso. 8 7 4,119,591 cashew nut particles, elastomeric modifiers and inor ganic modifiers in a fixed relationship, said non-asbe claSi.m 4, whTehreeinorsgaaindicinboargseanfircicmtioondifmieartserairael, sae*lecrteecdited in stos fibers and phenolic resin matrix providing struc tural strength for allowing the friction lining to with from a group consisting of barytes, whiting, talc, rottenstone, wollastonite. pumice, iron oxide powder, copper stand dynamic repeated engagements with a rotating member and providing a substantially uniform wear S ox4id.eTphoewodregra, nciacrbboanseanfdricstiiloannizmedatmeriinaleraasl praerctiitceldes.in claim 1 wherein said non-asbestos fibers include up to rate up to 600* F. during a dynamic engagement. 2. The organic base friction material, as recited in 10% fiber glass fibers. 7. The organic base friction material, as recited in claim 1, wherein said phenolic resin includes at least 10 claim 1, wherein said non-asbestos fibers include up to 12% dry phenolic resin powder. 3. The organic base friction material, as recited in 10t%. Twhoeodorfgloaunricfibbearsse. friction material, as recited in claim 2, wherein said phenolic resin includes up to 18% liquid phenolic resin to attenuate segregation of said c1l0a%imsi1lawnihzeerdeimninsaeirdalnfoibne-rass.bestos fibers include up to elastomeric and inorganic modifiers prior to the appli cation of heat to the mixture cla9imT1hewhoerrgeainnicsabidasneofnr-iacstiboenstomsaftiebreiarsl, ianscluredceiteudp tino 10% carbon fibers. 4. The organic base friction material as recited in claim 3, wherein said elastomeric modifiers is selected cla1im0. 1Thweheorreginansiacidbpasheenfroilcictiornesimn aintecrliuadleassatrelecaitsetdS%in from a group consisting of natural and synthetic rubber 20 liquid resin scrap, natural latex, crude molasses, and asphalt 25 30 !< 40 4? M'. 60 65 TRANSACTIONS Rodger F. Ringham/President M. J. Kittler/Treasurer Joseph Gilbert/Secretary & General Manager PUBLISHED BY: SOCIETY OF AUTOMOTIVE ENGINEERS, INC./400 Commonwealth Drive/Warrendale, Pa. 15096 750874 Friction Materials for Small Car Solid Rotor Applications John P. Kwolek Automotive Control Systems Group, Bendix Corp. WITH CONSUMER INTEREST in lower priced vehi cles and improved fuel economy on the increase, domestic vehicle manufacturers are giving more serious thought towards producing sub-compacts (vehicles having curb weights less than 3600 lbs.). Foreign vehicle manufacturers have pro duced vehicles equipped with solid rotor disc brakes in this weight category for over a de cade, but most American manufacturers have b e e r hesitant to use the solid rotor disc brake systems found on a majority of these lighter weight cars due to several factors. From the brake engineer's point of view, while solid rotors offer lower cost, the ven tilated rotor offers substantial improvement in brake cooling over solid rotors thereby lowering the brake lining temperatures encoun tered during usage. The front brake tempera ture profile for a durability test of a 1973 Domestic Disc-Drum Station Wagon is illustrated in Figure 1. This vehicle had standard venti lated rotors, which weigh 27 lbs. each; the brake test weight was 5860 lbs.; operating tem peratures generally ranged between 150 and 3U0F. The same durability test was also con ducted on a 1973 European made vehicle equipped with U-wheel disc brakes. Brake test weight of this vehicle was 2800 lbs., with the solid rotors weighing only 6 lbs. each. A comparison of the front brake temperature profile for this vehicle (see Figure 2) with that of the 5860 lbs. Station Wagon test indicates the average brake lining temperatures increased 75F, with peak temperatures I 5O0 hotter than those experi enced on the heavier station wagon. Several differences can explain these re- CHECK PO IN TS Fig. 1-Average front brake tenperature pro file, 1973 station wagon 5860 lb G . V . W . , ventilated rotors, 11 cycles suits with the most influential factor being rotor weight and design. The purpose of dis cussing these temperature profiles is to empha size the fact that the lighter weight vehicles equipped with solid rotors require linings which can successfully operate at higher temperatures than those experienced on the heavier domestic vehicles presently produced with ventilated rotors. ABSTRACT Semi-metallic friction materials recent ly developed offer significant improvements in lining life, rptor compatability and noise over organic friction materials on small cars equipped with solid rotors. Improvements originally predicted from full brake inertia dynamometer tests have been verified on ve hicle durability and fleet tests. 2369 2370 J. P. KWOLEK CLASS A - CONVENTIONAL ORGANIC------CLASS B - HEAVY DUTY ORGANIC----------- LINING TEMPERATURE - *F Fig. 3-Average wear versus temperature charac teristics, inertia dynamometer, 1740 lb wheel load, ventilated rotor Fig. 2-Average front brake temperature pro file, 1973 sedan 9 2800 lb G.V.W., solid rotors, 11 cycles TYPES OF FRICTION MATERIALS Friction materials are designed for speci fic applications, with the composition and method of manufacture determining the particu lar properties of any specific material. The primary function of the friction material is to produce a relatively high constant coeffi cient of friction under the conditions antici pated in use. The friction material must also exhibit excellent resistance to wear and opposing surface compatability under these same conditions. A previous classification of friction materials (1)* gives some insight into the fundamental compositional differences and how these differences affect friction and wear in brake lining presently used by vehicle manufacturers. The organic friction materials presently used on domestic passenger cars equipped with ventilated rotors, which are referred to as Class A materials, are fundamentally organic in nature excluding their inorganic asbestos content. "As a class, these materials are reasonably quiet, give respectable durability and, under most conditions, perform their frictional purposes ..." namely, maintain ac ceptable friction and fade resistance. Class A type friction materials are not generally found on solid rotor applications because: ' 1. Lining wear rates increase exponential ly at the higher operating temperatures (Fig ure 3). Numbers in parentheses designate References at end of paper. 2. They exhibit more fade and over recovery when compared to Class B organics or semi-met- allics (Figure k ) . Organic friction materials designed for heavy duty (Class B) generally have higher in organic contents to improve their high tempera ture wear resistance and fade resistance. A b rasives are generally added to achieve higher friction. Historically, these types of mate rials have been used on solid rotor applica tions because they are more suited to higher operating temperatures than Class A type or ganics (Figure 3) and the fade performance (Figure k ) demanded by this class of vehicles. FADE RECOVERY STOP NO. Fig. 4-Green fade and recovery, 1973 sedan 9 2800 lb G.V.W., 4 solid rotors, (fade 60 tnph, 15 fpsps, 35 second interval), (recov ery 30 mph, 10 fpsps, 1 mile interval) FRICTION MATERIALS But, as so commonly found in friction material development, improvements in one area usually results in losses in other areas. Class B materials generally exhibit higher low tempera ture wear rates, and frequently either groove, score or wear th e mating r o t o r surfaces. They are also quite prone to generate objectional noise. The success of sintered metallic-ceramic friction materials for specialized applications such as Jet Aircraft Brakes, Heavy Duty Clutch Facings and Police and Racing Car Brakes sug gested metallic composites would some day find usage in Automotive Braking Markets if refine ment could be made. Semi-metallics, the third class of materials, rely heavily on iron, steel and graphite substitutions for the organic and asbestos materials usually found in the Class A materials. But, unlike the sintered metallics, semi-metallic3 can use organic components to add desirable properties. As in all friction materials, the use of abrasives must be mini mized in order to maintain acceptable mating surface compatability. HISTORY OF SEMI-METALLICS The semi-metallic formulations developed in the 6 0 's for heavy duty ventilated rotor applications were first released on foreign vehicles equipped with solid rotors. These vehicle manufacturers released semi-metall ic formulations for police cars and quickly ex panded their usage to taxi cabs ar.d a few vehicles sold to the general public. In 1970 domestic manufacturers released semi-metallic formulations for the front (ven tilated rotors) disc brakes of police cars based on the success of these materials in meeting Los Angeles Police Dept. Braking Stan dards. (2) By this time the advantages of semimetallics over conventional organics were clearly understood: 1. Improved friction stability. 2. Improved fade resistance. 3. Excellent high temperature wear resis tance. L. Minimal speed spread. 5. Excellent compatability with rotors. 6. High performance with minimal noise. Even these with advantages, widespread usage could not be anticipated on domestic ' vehicles sold to the general public because of the additional costs. Raw material mix cost represents the major factor in the pre mium prices of semi-metallics. These compounds generally weigh approximately twice as much as Class A organics and use materials which cost more per pound than those found in con ventional Class A organics. The smaller sized pads used in small ear solid rotor application drastically reduce the affects of raw material mix cost and semi-metallics can be competitive with many of the higher priced heavy duty 2371 (Class B) organics on small cars. With the advent of FMVSS 105-75 testing, it became apparent that, while semi-metallics showed excellent friction stability from 2nd through Lth effectiveness, the pre-bumished f r i c t i o n had to be im p ro v e d . Still another area of concern was initial wear (referred to by some as low temperature wear). One particular type of dynamometer test procedure, a wear versus temperature schedule, indicated higher wear rates than those experi enced with conventional organics at low tem peratures. Subsequent dynamometer tests and microscopic examination of the materials proved this to be an initial wear problem and that conditioning of the lining at higher tem perature and by extended usage dramatically iii5>roves lining life at low temperatures (see Figure 5). The analysis of numerous vehicle tests conducted confirmed that the wear rate of semi-metallic formulations improves with usage (see Figure 6 ). PREVIOUSLY CONDITIONED TO 2 5 0 *F PREVIOUSLY CONDITIONED TO 4 0 0 * F - PREVIOUSLY CONDITIONED TO 5 5 0 *F - <.020 g .0 1 0 1.000 TOTAL STOPS AFTER PRECONDITIONING Fig. 5-Effects of preconditioning semi-metal lic on subsequent low temperature incremental wear, inertia dynamometer, 1740 lb wheel load, ventilated rotor, all stops from 50 raph, 12 fpsps deceleration Fig. 6-Incremental mileage projections for Detroit Durability of Semi-Metallic, 1973 domestic sedan, 5560 lb G.V.W. Even with this knowledge, the development program for semi-metallics concentrated on im proving pre-burnished friction and initial wear characteristics. The program led to sig nificant improvements and resulted in the issuance of a patent (3) for this new type of material. Pre-bumished front torque was in creased 2 0 % and initial low temperature wear rates were decreased to levels comparable to those obtained with conventional Class A or-