Document 4vEoZ36xOr2BymdVMmzkqnN4G

FILE NAME: Allied Signal Bendix (ASB) DATE: 1960 July 19 DOC#: ASB204 DOCUMENT DESCRIPTION: US Patent - Frictional Material - 292 United States Patent Office 2 ,9 4 5 ,2 9 2 Patnnt.d July 1. IMO 1 2 metallic lubricant melts and exude* to (be surface of the element during use to stabilize the frictiooal char 1M 2K acteristics of the dement. Further objects and advantage* of the praecnt inven FRICTION MATERIAL e tion will be apparent from the following description, ref WOtam A. U A k , M-, m i Itntaad F. Koekrtag, Dij M , O tta, a i p t n 1 Gtattml M olon Corporation. Datioti. Mldk, i coepormtino t Dataware e r " " * being had to the accompanying drawings wherein preferred embodiments of the present invention ere d ear ly shown. In the drawings: F M N t. 2 2 ,195ft, fcr. No. T 7 7 I 10 Figure 1 is a perspective view of a typical brake band n CtataB. (C L S ^ -tttJ) 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 t a invoouae rotates to friction material! and k par- 15 friction materials including different metal lubricants aad --t^ concerned with ferrous friction member! for showing coefficient of frictioo plotted against time and te at dutches, brake* and the like temperature. T tat application u a cominuauon-in-part of applica Figure 4 is a perspective view similar to Figure 1 tion &X. 6ft4954, tied September 19. 19S7. bow aban showing another means of attaching the friction lining doned 20 to the shoe An object of the invent!on a to provide a ferrous fru Figure 5 is a view of one segment of the friction ma tion facini consistm i 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 m ath with metals that are substantially insoluble in iron ing conditions are encountered at friction surface* used In carrying out the above object, u is a further ob 25 for b.akes, clutches and the like. These extreme condi ject of the mvnotion to form the friction member from tions make convenuonal nonmetallic clutch facings and a sintered m ature of iron powder with graphite which brake linings costly to use since these matenal* must op member also contains a lubricant metal in the form of erate below cenain limiting temperatures if tbeir effi lboiysms uatahd, bwishmeruetihn-lea'-daphanlleoysm, akanesd ubpismausthu-bcsatdanmtiiaulmpoarl 30 cainedncoylhiesr todebveicemsationtaliimnend thwehitcehmpreeqrautiureresscooIltinigs, mtheedriea tion at the member A still further object of the invention is to provide a fore. desirable to provide facing materials for clinches, brakes and the like which can withstand considerably ferrous friction member which consists essentially of higher temperatures than the usual nonmetallic materials garalpuhbirtiecartianngginmgetbael twsuecehn 2as05bisamnudth30o5r bbiysmwuethighat llaonyds 35 aacntderwistbicu*b tmhraoiungtahionustubthsueiDr Uoaplelyractionngsttaenmt pferircattiuornealracnhgaer wherein the alloy has a roelung point no: greater than the Metallic facing material* made from tmterad metals me lung point of bismuth and wherein the othc: 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 dCteustics od these elements are considerably belter than ject where bismuth or a bismuth-lead alioy is used as a nonmetallic elements, it has been found difficult to con lubricating metal, to include small quant.tic* 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 frictioo during suc It is a further object id some cases to utilize small cessive slop* makes them erratic in their operation and. quantities o ' sulfur not over 15 in combination with 45 therefore, generally undesirable the iron either as an added ingredient or as an impurity Recently, improved friction facings have b m pro m 9m iron used and'or a ceramic matenal such as mul- posed of the metallic type wherein substantial quantities Use m quantities of less than 15 of graphite have been incorporated therein to smooth Another object of the invention is lo provide the fer out the coefficient of friction to some extent over a wide tout fraction 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 of a tintered farrows material of different composnion However, when heavy duty service is encountered such aeonedxptenewstvirelystrthenegrethtothan the friction element and bonded 66 asps.eefdosr, etxhaemseplfencwtiiotho tmaxaitcearbiaslsbudsosensoot r asltwoapyssfrmomainhtaiginh More apectfScertly. it ts an object of the invention to their stability within the range desired pvovrde a sintered ferrous friction element consisting The present invention is directed to a fraction material cwemially of graphite 30 to 45 parts by weight, copper which has a stabilized coefficient of friction and, thnre t0hetroeof156 ptaorts16bpyarwtseibgyht,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 include sulfur and mullite in the above duty application We believe that this stabilization of formulation. 66 friction characteristics is accomplished through the use Another object of the invention is to provide a fer of a metallic lubricant which is transitory in character rous friction member containing substantial quantities of at the surface of the element, that is to say, the lub.i- graphite together whh a lubricating metal which is sub- culing metal is held in Ihe solid state within the pores of rramiaJly insoluble in the metals making up the 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 tag aubaequent use of the friction element whereby the of the element and doe to its expanion, wilt exude onto the surface Si the element and provide a fluid lubricant itterface between the element and the brake drum or which stabilize* the frictional characteritucs of the tie other rubbing surface, etc. meat while maintaining the detired frictional charactei- Some examples of suitable mixtures are at follows, istic* thereof as provided by other component* of the ele all proportions being in parts by weight : ment & It is understood that, in the description to follow, the E,t K * S l i 4 E . S K i ft ferrou* friction element may be uted in connection With brake band* or clutch dues or brake ditc* as the case P p o o ff or K id u r c J O xide Iron may be. For example, in Figure 1. a conventional brake (w ith or ifbout r*m- h t n M f u lf 'i r i ....... ....................... l-rt loo |Or too too band is shown at 2 t which includes a plurality of pads 10 t t r j p t i i l t ......................................... .. . 46 10 46 60 of friction materia) 22 attached thereto In Figure 2. B ism u th .. . . .. A 6 to 9 16 Ift a clutch disc or brake disc is shown at 39 which includes S S T : - : . : . - : : : : ........... 4 a steel disc 32 having a friction layer 34 attached thereto M u ll t t f ........................................... .7 .76 6 Example 7 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, tities of graphite are highly desirable to supply tbe de capable of passing through a 100 mesh screen arc inti sired frictional characteristics to the element In this mately mixed and are briquetted into the detired shape connection, graphite ranging from 209c to 309c by weight under briquetting pressures ranging from 60,000 to of tbe element is incorporated in tbe element together with a lubricating metal such as bismuth, or alloys of 20 80,000 pounds per square inch and are then sintered under nonoxidizing conditions for from 30 to 40 min bismuth with metals which are insoluble in iton and utes at temperatuers ranging from 1800* F. to 2000* F. wherein tbe melting point of the alloy docs not exceed In each case, a sititered friction element is formed which tbe melting point of bismuth, for example, lead-bismuth will exude bismuth, bismuth-lead, etc., as the case may alloys and cadmium-bismuth alloys The low melting be, at tbe 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 at or below the melting point of bismuth In this con nection. an alloy of 88r( lead and 1291 bismuth has 67 parts --250 mesb sponge iron powder (combined sul substantially the same melting point of bismuth where..s fur up to 1% by weight) the eutectic alloy of lead and bismuth which contains 30 20 pans anificial graphite (density 1.85 grams per cc., SJ'-'i?! bismuth and 44 i l r - i melts at about 255' F --325 mesh) Thus, bismuth-lead alloys where the minimum bismuth 8 pans 150 mesh copper powder percentage is 12fl may be used ,,s a substitute for pure 5 pans 100 mesh bismuth powder bismuth according to use Mnce an\ alios having this These ingredients are intimately mixed and are briquetted composiuon will meli ai or below the melting point ot 33 at 60.000 pounds per square inch and are then sintered bismuth In this connection the service requirements of for 40 minutes in a nonoxidizing 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 seised by the higher melt-ng order of 3720 pounds per square inch point alloys whereas light duty applications may make use of the lower melting pom; alloys In all vases it Oi Example 8 is desirable that the melting point of the lubricating 67 parts --250 mesh sponge iron powder (with 1% com metal is in the range of temperature attained during nor bined sulfur) mal use of the friction dement and tliv^e Cv.nd.um-, 15 pans powdered artificial graphite (density 1.85 grams therefore govern to a large degree the choice of materi.il per cc., --325 mesh) Similarly, alloys of bismuth and other metals mu> be 45 15 pans 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 pans ISO mesh copper powder soluble in iron and alloys wnf, b.vmuth to form low melt 10 parts 100 mesh bismuth-lead (50-50 mixture) with ing point alloy? In thi- connevtion. an alloy of 259V bismuth and 95r~, cadmium has substantially the Same 50 or without Vs part 60 mesh synthetic mullite melting point of pure bismuth wherea' the eutectic alloy These ingredients are intimately mixed and briquetted of 60r< bismuth and 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 that we have chosen a lubncat- It is understood that the lubricating metal such as tng 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 the sin.enng 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 not reached upon operation of the friction element w-ill occur in situ during tbe sintering. whereby erratic results occur due to the fact thjt the All of the above friction elements made by any of so-called lubricating metal may be liquid in one case 65 tbe aforementioned examples are preferably bonded to a and solid in anothei more dense and stronger material during the sintering Therefore, in each instance, the low melting point to enable them to be riveted or spot-welded to k steel 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 ve n ding peratures within the normal operating temperature range 70 Smiley application, S.N $96,266. filed July 6, 2956, as of the fraction 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 melt 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 75 comprises a mixture of about 95 parts 100 mesh sponge 5 iron powder, 5 peril low dratity powdered graphite 6 cate, h wW be aotad (hat fee coaM eot of frietiee a t (1.61 (rum per cc.. --325 meth), tad three pen* of the Kahg eeeuMc until the Mieperatuie of epwution ex molybdenum rtiadphirl* powder (250 aiaeh). 11m m in- ceeds the malting point of the habricaM matai at wMafi (n d n a u i n ialiaittly mixed u d the mixture U pleeed time (hr ooeffteim t of friction levels off aad baccate* ia a die is deeired quantity. Any of the aforementioned 8 sitbikmd friction onerrial mixes ii the* filled inso the die aad the Through* mi* specaAemioa, (be teem cmamic ma- two layer* are simultaneously hriqumted at preeauree of rial * used lnpaha with muhita m am ambedaaaai frua 60,000 to 60,000 pounds per square och. The tharaof. ta is to be nadamtood that this mtmpl* is il briquette it eiaiered under condition*, time* and tem lustrative only and that clays, silica magnesium oxide, perature* noted in any of the examples A coextensively 1'* 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 While the embodiments of the present invention at BMotiooed before, the application S N $66,266 gives a herein disclosed constitute preferred forms, it it to be detailed disclosure of the method of making these com understood that other forms might be adopted. posite friction elements end the present invention is di 16 What is 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 tion 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 it shown at 46 in Figures 4 and 5 The re 60 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 6s 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 ferrous base 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 all 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 33 mg point of hismuih in quantities of from 3% to I0r" the friction material exceeds 25%. different manufactur by weighi ing technique- are required in order to form an elerr.e .i J A fnciion material for use as a friction facing ele having sufficient strength for the intended purpose and. ment comoting essentially of a sintered ferrous base to this end. different types of graphite are used to over come problems which arise when using either lype of having dispersed therethrough graph'te in quantities o ' from 20% to 30% by weight, together with a metal taken graphite alone These manufacturing lechnique; form no from the class of bismuth and bismuth alloys with metals pan of this intention and are fully disclosed in copend insoluble in iron wherein said alloy's have a mrlung point ing application 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% lo 10% by weight the reasons for mixing the different types of graphite 5 5 A sintered friction material for use ns a frui or are set forth In this connection, so far as the finished friction element is concerned, there is no substantial dif facing element, consisting essentially of iron in.lud ng sulfur up to 1% by weight thereof. 100 parts graphite 30 ference in the operational characteristics of the different lo 45 parrs, copper up to 15 parts, and a m etJ inker types of graphite but the strength of the finished cle from the class consisting of bismuth and bismuth alloy ment is markedly enhanced by mixing two types of 0 0 with metals insoluble in iron wherein said alloys have graphite melting points not in excess of the melting point of hu While the friction elements utilizing graphite in the murh. 6 to 10 parts, said proportions being expressed as order of 2051 have good frictional characteristics and parts by weight. under normal operating conditions function well, there 6 A sintered friction material for use as a friction is some tendency toward noisy operation under certain gg 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 tins noise condition decreases to a point where the ele 30 to 4 parts, copper up to 15 parts, nullitc up to ment is comparable with conventional nonmcullic ele by weight, and a metal, taken from the clas. consistm*; ment. at 25% of giaphit; and above In other words, of bismuth and I i>i,uiih alloys with metal -iisol-tblc m as the graphite increases, the tendency toward noise de 00 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 with conventional mating surfaces such at steel 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 05 graphite 30 to 45 pans, copper up to 15 parts, and bis other metals providing the lubricant metal doe* not alloy muth 6 to 10 pans, said proportions being expressed as therewith at operating temperatures. For this reason, the pans by weight. metal of the mating surfaces should be chosen from met 8. A sintered friction material for use as friction als and alloys that do not form imermetallic compounds facing element, consisting essentially of iron 100 parts. with the low melting point metals such as lead, bismuth 70 Phil* 30 to 45 paru, 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 proponions 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 $% 9. A sintered friction material for use as a friction fac- bismuth alloy instead of the bismuth-lead alloy, la aacfc 76 iag element, consiatiag eaaentially of: iron 100 pens. 7 graphite 30 to 45 paru, copper up to 15 pant, and a bis muth-lead alloy 6 to 10 pans, said proportioni being ex preaied as pans by weight. 10. A heavy duty brake comprising a friction elemem. consisting essentially of iron 67 parts, graphite 20-30 6 parts, a bismuth-lead alloy wherein the bismuth and lead are in equal proportion* 5-10 pans, copper 8 parts, all proportioQs being expressed in p ent by weight, said eie- 8 meet being coextensively attached at ooe surface thereof to a strong metal supporting member. Rafereweee Cited in the file of this patent UNITED STATES PATENTS 2.072,070 2,416,830 2,863.211 F ish er........ .............................Feb 23, 1937 H euberger............................. Mar 4. 1947 Wellman ................................Dec 9. 1958 July 19, 1960 filo! Nor 98. IM S W. A. LUTHER. JR., ET AL FRICTION MATERIAL 2,945,292 2 Sh**X*-Sh*t 1 ** VOPB9 6utiM*ex puoioy M P V iO i||iM S V O li& A N I Coefficient of Friction Time In Minutes Fig. 3 ^ )im H tu i|S 8 Temp, of Broke Drum eeet > *n p*tt4