GB2247053A - Thrust bearing assembly - Google Patents

Abstract

A thrust bearing assembly 20 made of synthetic resin and for use with an automobile thrust-strut type suspension comprises a lower casing 21, an upper casing 22, and a bearing piece which may be integral with one of the casings or may be separate 62. The bearing piece is disposed within the upper and lower casings upon snap-fitting a hook portion of an annular suspended portion of the upper casing with an engaging portion of an annular protruded portion of the lower casing. Two annular inner labyrinth portions and two annular outer labyrinth portions are respectively formed at inner and outer peripheral portions of the thrust bearing. <IMAGE>

Description

ccr.--err,s a thrust it relates of resin type M a c f e rs c n c r wheel

cars.

such a type in whIch ro- cf a strut asse-l-ly is rotated when the a pist asse..'.,'y is rotated together with coil springs by a steering operation and another t _Te in which the piston rod is not rotated. In both of the types, a thrust -ing member of the bearing is required between the inojnl,,.

2 strut asse=2:)1v.

Roller bearings using balls or needles, or resin have sliding type thrust bearings made of syntl been em-ployed so far in these portions.

A dust seal made of an elastic rubber member is mounted at the outer circimiference of the sliding surface for the thrust bearing inade of s--ithe-lic resi-for preventing the intruslon of dust or the like fro= the outside of the bearing to the sliding urface.

In the pror art describe,,' above, Sin-Ce a dust seal is dispose--," to the outer circ-u.-n.fereri--e of the slidina surface for the thrust bearinc, there is a drawback that the s"';.id-ng frictional force is increased upon s--eerJng thereby requIring great steerIng force.

The present invention is achieved in order to overcome the foregoing drawback in the prior art and it is an object of the invention to obtain a thrust bearing made of synthetic resin capable of preventing the intrusion of dust or the like without using dust seals made of elastic rubber members and thereby preventing increase of the steering power upon steering operation.

1 i a first thrust bearing for use with an automobile thrust-strut type suspension having a strut incorporating a shock absorber, a piston rod inserted in the shock absorber, a mounting member for supporting the piston rod to the automobile body, and an upper spring seat loosely engaging the pistcn rod, the mounting member and the upper spring seat having opposed, substantially planar surface Ofset from each other and defining an annular space between them, said bearing being adapted to be received in the annular space between the upper spring seat and the mounting member and adapted to receive the a cylinirical portion having a substantially planar upper surface, a lower surface, an outer circumferential surface, and a penetration aperture of circular cross-section coaxial with said longitudinal axis of said lower casing, said penetration aperture being adapted to receive the piston rod of the suspension therein; and 4 substantially planar upper and lower surfaces and an Oerenl-ial surface, said lower surface of said outer circx-,ml.

to r,-,atingly engage the upper collar portion being adapte^ surface of the upper spring seat of the suspension, and said collar portion including an annular inner lower 1 ip portion extending, upwardly from said upper surface of said collar portion coaxially with sald longitudinal axis upper. surface of said' collar portion, said inner lower lip pcr-tion having a diStal end offset fro-,, said u---:-,er surface of said collar portion, said collar portkon further including an annular protruded porkion extendling upwar,."L.-,- from said upper surface of said collar portion said collar portion, said protrude-,' portion hav-'L.,nc an outer circurrferential surface and an outwardly extending engaging portion formed on said outer circumferential surface of said protruded portion, and said collar portion further including an annular outer lower lip portion extending upwardly from said upper surface of said collar portion coaxial with said longitudinal axis of said lower casing and defining an i c--oc-.-e..:^ ccope:at--c.-. w-z--. Said -,=er a.7.= a 7. cu, ter a r c r c G ve W th E J p I_---.;- - - pcrz-J--n, said cuzer 11cwer pcr-L--4cn a d-Stal end offset from said upper surface oil said collar portion, and said inner annular groove having a bottom surface, said inner lower lip portion having an outer diaj-.ete.- 11d111 and said outer lower lip portion having an inner di&me--er "d2", respectively, "dl" being s.-. ialler than "d2"; an upper cas'.-,c made of synt-hetic resin an.-J; up, a ax-,,---, Said per casing a disk-like pcrt-4c.-, ha-.-inc substantially planar upper and lower surfaces, an w-ter circ=..ferential edge, a circular aperture forme-' at the center there,-f coaxial wIth said longitudinal axiss c--- said upper casing and, defining an inner e,-;ce, an annular outer upper lip portion from said lower surface of d pc:--,on coax-'a! with sad longitu;inal s ai -- L - axIs cZ said upper casing, and an annular suspended portion extending downwardly from said lower surface of said disk-like portion and formed integrally with said outer circumferential edge of said disk-like portion and defining an outer annular groove in cooperation with said outer upper lip portion, said upper casing further including an annular inner upper lip portion extending f - -,- lc-,;er r o= S - - p-:.='-n coax4a-! w-h ca.'A Cas4 ing and intec th an inner ,rally w.

: said disk-like portion and circwrf erential portion of defining an inner annular groove in cooperation with said annular outer upper lip portion, said upper surface of said disk-like portion being adapted to matingly engage the lower surface of the mounting me.r.Lbe.- of the suspension, said circular aperture being adJapted to receive the piston rod, of the suspension therein, said er and outer upper annullar- lip portions eacI-. ha-jing a d-Stal end offset from sa-Jd.-lowe.- surface of said disklike portion, and said suspended portion having a distal e o47se- from said lower surface c'." said disk-like portion and an engaging hook portion formed at said distal end for cooperation with said engaging portion of sa,d:', protruded portion; and f synthet a bearing piece made ol- I-ic resin and coi-.IDrising an annular plate having upper and lower surfaces and an inner diameter greater than "dl" and an outer diameter less than "d2", said bearing piece being received in said inner annular groove of said lower casing; said hook portion of said suspended portion of said u-. casing teing snap-fitted with said enga-inc 1-pe- t- - i.

1 c.wc-r cas..= C c- said bearinc piece being slidably abutted a-,,a-,nst said lower surface c.' said disk-like portion, said dist-al encE c.lr said inner and outer upper lip portions bein; overlapped radially with said distal ends of said inner cuter lower lip portions, respectively, to define an h in.ner an,-: cuter c.-eri-appe-5 portions, said lower surface abutted apainst sa' grcc,.7e, whereb.; A Preferred fc= of such a t-r-st bear.,--, -'s. one in which said c:,,"r,.:-zal pz:.z-'cn further has an annular innermost from sai upper cf porticr, adjaccent and offset stepwise frc.-. sa-d penetraticn aperture, said innerniost, lower lip pzrtic7. definin; a cylindrical aperture having 11 a slightly greater than that. of said penetration aperture and defining an innermost annular groove in cooperation with said inne.r lower lip portion, said innermost lower lip portion having a distal end offset from said upper surface of said cylindrical portion, sall- E - t.h S a_--- d 1 end c f irmermost upper lill portio.n extenSing downwardly from said lower surfacce of said d-,sk-like portion and fc-.,.,eA integrally with said i, =er circ=ferential edge of said disk-like portion, and defining an innermost annular groove in cooperation with said inner upper lip portion, s'd innerm-st upper lip portion having a distal end a r_ - -":0 N..

cffset f".cm said lcwer surface of said- disk-like Sa-2d distal end of said upper lip portion be-2-c of n7,e- = of the hrust beari.

present a-J-.ra:-.tacer,.is effects as desc:r-be-' can be Scince four tight seals are by the in the snap-fit port-4o7.

between t-e portion of the upper casing and the prctr,u--'-e-:' of the lower casing and in the overlapped, portions between the inner upper and lower lip portions and between the outer upper and lower lip portions respectively, intrusion of dust or the like from the inner and outer circuriferential surfaces of the bearing to the sliding face of the bearing can be prevented. In addition, since dust seals made of elastic cuse.- sz fa: c-== be deletet, se.I.:: the sze=-r-:nc due tz the dust se-ais can he anA- operation is poss;",le for a lone., period cf tLne Further, since the upper casing and lower casing can be engaged by snapfitting, the asserbly work can he ccn--jcted extremely easily.

According to the preferred thrust- beaxing of the- cf the lc;.;er casing, in the Cetv.ec-.- t.-le a:-n,..ilar innermcst upper I- 1J- = an--' the annular in p pc:-t- lower lip portion, intrusion of dust or the like from the inner and outer circu:-,.fere.- itial surfaces of the bearing to the sliding face of the bearing can be prevented. In addition, since dust seals made of elastic rubber rne.-,ber used so far can be deleted, undesirable increase in the steering force -ing.

upon stee---:, operation due to the dust seals can be Fi= th.er, s, nce um-.Der cas --n-c and- the lower casing can be engaged by snap-fittin.-, the asse=2:ly work can be conducted extremely easily.

in the constitution of the thrust bearing according to the present invention as described above, it is necessary that the synthetic resin constituting the casing, the upper casing and the lower casing is excellent in mec'nanical properties such as abrasion resistance, innact s.-,----k ressistance and creep resistance.

Further, it is particularly preferred that the bearing Iv fitte-5 to the casing or the bearing p4 bodv slidab Lece, disnosed wi4tt-hin the upper and lower casings has a self lu"bricity, and there can be used preferably, for exam.-le, polyacetal resin, p--Iva:-,.-;de resin, polyester res-4n, such as polyhutylene rerephthalate (P-':) and polyolef-'Lne resir.

such as po"--,,-et',I-.vlene and polypropylene, as well as polycarbonate resin. Similar synthetic resin to that for the bearing body or the bearing piece can be used for the casing, the upper casing and the lower casing and it is desirable to use a synthetic resin material that exhibits preferable friction characteristics when combined with the synthetic resin used for the bearing body or the bearing piece and shows a relatively high rigidity.

1 1 The invention also provides a thrust bearing for use with an automobile thrust-strut type suspension having a strut incorporating a shock absorber, a piston rod inserted in the shock absorber, a mounting member for supporting the piston rod to the automobile body, and an upper spring seat loosely engaging the piston rod, the mounting member and the upper spring seat having opposed, substantially planar surface offset from each other and defining an annular space between them, said bearing being adapted to be received in the annular space between the upper spring seat and the mounting member and adapted to receive the piston rod therethrough, said bearing comprising a lower casing made of synthetic resin, having a central aperture and an outer upwardly extending engaging portion, an upper casing made of synthetic resin, having a central aperture and an outer downwardly extending suspended portion snap fittingly engaging said engaging portion, and a bearing piece between the lower and upper casings, being separate or on one of the casings. Further the invention provides such a thrust bearing including upper and/or outer annular ribs extending respectively upwardly from the lower casing and downwardly from the upper casing and being overlapped to provide seal(s). Further features disclosed in connection with the various embodiments described herein can, according to the invention, be used in bearings of the invention in suitable combinations.

Exa=,Ples of desirable coi-nhination of resins are as shown in the table below.

Table

Bearing body or bearing piece Polyacetal Polyamide Polyethylene Casing, UpPer c(-.xr>.i.ng Friction Abran ion or lower casing coefficient amount (mm) Polyamide 0.05 0.020 Pol-yacetal 0.04 0.021 Polyacetal 0.04 0.030 Polyacetal 0.06 0.050 PBT 0.07 0.045 Polyacetal 0.06 0.025 Steel 0.11 0.095 Polycarbonate Polyacetal Polyacetal Polyacetal 1 1-1 0 11.

the tazle, the sh-,-w the result t,-n.,er thie followimp test cc7.,,-:' i tions.

Test Condlition Thrust loa.-4: 350 kg, angle of swine: 351, velocity of swing: 60 cpm, lubrication: silicon grease was coated on the sliding face upon starting.

The abraslon amount indicates the amount of dimensional change (mm) in the bearing body or the bearing p.ece after conducting 1,000,000 cycles of the test.

If the of the synthetic resins fo-r the casing and the bearing body, or the co,-I3Dination of the sy.-,'-hetic resin for the upper and- lower casings and the bearing pece is. preferably selected as described 1 the bearing is a-o-.-e, s =:e the sliding face c. with h-he cc.-.--ination of synthetic resins excellent in the self-lubricity, the friction coefficient is low and stable steering power can be maintained for a long period of time.

This invention will be explained more specifically while referring to the accompanying drawings, by which the foregoing objects as well as the constitutions of the present invention will become more apparent.

-'14 e Z: Emb c e _n S t c hereinafter are- civen for easy of the present inventlon and various modi-fications may be X possible by those siCilled in the art without departing - invention as clearly shown in the scope of the present the scope of the claim for patent.

BRIEF DESCRIEMON OF THE D1RJAWINGS Figure 1 is a longitudinal cross sectional vie-,,; of a strut assembly equipped. with a first thrust tion; bearing a--ccrd-.-.c_ to the present inve.nt Figure 2 is a longitudinal cross sectional 1-hrusi- vie-;,; of one e-.bo, ent of the first - bearing according to the present invention; Ficure 3 is a plan v-Je-,; for the bearing body shown- in Ficurre 2; Ficure is a botto-, view for the bearing shown in F-Jc,,.i7e 2; Figure 5 is an enlarged cross sectional vie-, for a part in a snap-fit portion shown in Figure 2; Figure 6 is a longitudinal cross sectional view of one embodiment of the second thrust bearing according to the present invention; Figure 7 is a plan view for the bearing body shown in Figure 6; 11 Figure a is a bcz-tc= view for the i Figure 9 is an, enlarged- cross sect-lonal view for a part in a snap-fit portion shown in Figure 6; Figure 10 is a longitudinal cross sectional view of a strut asse-ibly equipped with a second thrust bearing according to the present invention; Figure 11 is a longitudinal cross sectional view of one e.-.bod2:.r,,en-k of the third thrust bearing accordIng to the present invention; F"r-e 12 shc.7. in Ficure 11; Ficure 1-3 is a bottom view for the bearing body sh.own in Figure 11; Figure 19 is an enlarged cross sectional view for a part in a portion shown in Figure 11; F-cure 15 is a longitudinal cross sectional view cf ar,--t.-er e.-,bod-,r, .ent of the third thrust bearine according to the present invention; Figure 16 is a longitudinal cross sectional view of a strut assembly equipped with a third thrust bearing according to the present invention; Figure 17 is a longitudinal cross sectional view of one embodiment of the fourth thrust bearing according to the present invention; is a plan v-,e-A for the bearing - 1E 7.1 v. --n I.Lg-re 11; I c -- r e 18 -4 s a p I a n v J, e w. E -- r -- c a s _: -, c -,..: -.

Figure 19 is a bottom view for t".-.e body shown in Figure 17; Figure 20 is a longitudinal cross sectional view of a strut assembly equipped wILth a fourth thrust bearing according to the present invention; Figure 21 is a longitudinal cross sectional view of one embodiment of the fifth thrust bearing according to the present invention; show.- in Figure 21; vi f a strut iew oA 22 1 -- a pian v-4e-,j f or C---- bearinc r 4 ece Figud.e 23 is a longitudinal cross sectional assembly equipped with a fifth thrust bearing according to the prdsent invention; ,'inal cross sectional Figure 2,1 is a longit= vie-.,; off one of a sixth thrust bearing shown in Figure 24; acco.----'-.c tto the present invention; is a plan view for the bearing piece Figure 26 is a longitudinal cross sectional view of a strut assembly equipped with a sixth thrust bearing according to the present invention 11 1 -1 F J cur e 2 -7 a i s a 1 c r. g i CL: J. n a I c r c s s s e c vJe- c:- one cf a seje.-.z.-- to the present invention; Fig-ures 27b to 27d are lonc.i-tuL..-inal cross sectional views of variant em.bodiments of the thrust bearing shown in Figure 27a, respectively; Figure 28 is a plan view, for the bearing piece shown in Figure Figure vie.... of a=ther accc---2--ng to the Ficure vie-,.. of a strut assem-bly bearing according to the Figure 31 is a 277; 29 is a longitudinal cross sectional e7,bc--"--,mer,t of a seventh thrust bearing present invention; and 30 is a longituJinal cross sectional a equipped' with a seventh thrust present invention; longitudinal cross sectional view of a strut asse:rbly e-,uipped, with an eighth thrust bearinc to the present invention; Figure 32 is a plan view for the lower casing shown in F4cure 31; Figure 33 is a plan view for the bearing piece shown in Figure 31; Figure 34 is a longitudinal cross sectional view of a strut assembly equipped with an eighth thrust bearing according to the present invention, shown in Figure 31; and - 1E - Fi.c.ure 36 is a plan view for the bearing piece of a 1 the eighth thrust bearing according to variant e:-,boiment o. the present invention; and Figure 37 is a longitudinal cross sectional view of the variant e,- bodiment of the eighth thrust bearing - invention.

according to the present in I-F-cure 1, a thrust asse-bly A comPrises a a shock abscrber and a pist-on rod .;.nserte- at c-.e en-5 into the shock absorber of the s-hrut f. - 1 an-- at the- cther en, c. the shock absorber.

T'-e c--'-er e.-- cf the rc-- 2 is securc--- b,,, means of a n,.t- se-at -7 is secured.' to the cuter -erent-:a- surface cf the strut 1, while an uppe,r seat 6 iS d---pose-2 opposing to the seat 7 and loosely engaped to the outer circumferential surface of J 2. A coil spring 9 is disposed between the uppe.

the ro. an.' the lower seats 7 and 8.

A first thrust bearing 20 made of synthetic resin of the present invention is disposed between the - portion 10 of the seat 8 and the mounting rne:-,bers flat and the thrust bearing 20 comprises a casing 21 made of -ic resin and a bearing body 22 made of syntheti-c synthet resin slidably fitte--" to the casino 21.

6 51 1 W'111 be made cn:= th. b e- pressent- inven.tion refferring to Figures 2 through 4 of th.e accompanying drawings.

A thrust bearing 20 cor,-.-p)rises a casino 21 made of synthetic resin and a bearing body 22 made of synthetic resin slidably fitted to the casing 21.

The casIng 21 includes a cylindrical portion .ion aperture 23 being alone a 24 having, a penetratlongitudinal direction thereof, a large width collar p--rt.on 25 for=ed integrally with an outer ace of the cvl4r,,-',rical por- c-rc=,.---erential ion 2 in a state where.one end' 24a.of th'e cylindrical portion 2,1 is protruded therefrcm, an annular protruded portion 26 ircurnnferential edge c-' forme integrally w.t.- an outer cthe collar pcr-l--Jcn 25 and an encacing portion 27 formez, truded to an cuter. surface of the prot porti= 2E. The collar portion 25 may be forned at a lower end of the cylindrical portion 24.

The engaging portion 27 consists of a tapered surface portion 27a formed from the outer circumferential surface of the protruded portion 26 to an lower surface of the collar portion 25 and a cylindrical surface portion 27b in continuous with the tapered surface portion 27a and reaching the lower surface of the collar 25.

T'.,,.-- bear_-= bo,_v 22 niade of sy=Inezic ress-n includes a cv'I--nd-:--caI 26, an a:

ir-ner, collar portion 29 formned integrally w--t',. an up-pper e-.,,- of an inner circunderential surface of the cylindrical bearing portion 26, an annular outer collar portion 30 formed integrally with an upper end of the outer circumferential surface of the bearing portion 28, an annular suspended portion 31 formed integrally with an circu=,ferentlall edge of the collar portion 30 and an engaging hook portion 32 formed at a lower end of the Pri su, s P e n a ed 4= 311. Tne lhook portion 32 consists cf a tapered surface portion 32a corresponding to the tapered rt,on surface portion 27a that constitutes the engaging po. 27 of the casing 21 a.nd a cylindrical surface portion 32b in continuous with the tapered surface portion 32a, and corresponding to the cylindrical surface portion 27b oil the engagirc p-ortio.n. 27.

T ring body 22 is fitted rotatably to the he bea. casing 21 by snap-fitting the hook portion 32 of the suspended portion 31 with the engaging portion 27 of the casing 21, whereby a tight seal is formed by the labyrinth effect in the snap-fit portion.

A plurality of recesses 33 are formed radially at the upper surface of the bearing portion 28 of the bearing body 22, so that the thickness of the bearing 11 - 2 1 A plurality of grooves 34 are fomied' each az a c r=,ferential pitch at the lower surface of the hearing the hearing body 22 and' each groove 34 is portion 28 oformed radially frorm the inner circum-ferential surface to the outer circumferential surface, and the grooves-34 constitute an oil reservoir for grease or like other lubricant. The bearing body 22 is fitte" to the casing a the bearing portion 26 21 such that the lower surface ol f the is slidablv ahuttef against the upper surface o collar portion 25 of the casing 211.

Explanation will be made specifically for one emhodiment of the second thrust bear, ing according to the present invention referring to Figures 6 through 9 of the accompanying dra-v. _4 - C S A, ti usz hearing 20 comprises a casing 21 r-na-, of syn--he-4 c- resin and; a hearing body 22 made of thetic resin slidably fitted to the casing 21.

s yn t The casing 21 includes a cylindrical portion 24 having a penetration aperture 23 being along a longitudinal direction thereof, a large width collar portion 25 formed integrally with an outer circumferential surface at the end of the cylindrical portion 24 in a state where one end 24a of the 2-7 cylindrical portic-n 2.- iss therefr-cm, am. ar-nular r)orzi--= 2ES w2t^.- an c.-.ter c-rcu:-,jerential edge of the collar portic.n 25, an to ferent, a! engaging portion 27 forn.ed to an outer circumi k- surface of the protruded portion 26 and an, annular lower -1 coaxially wIth the penet lip portion 41 forme h-ration aperture 23 at an upper surface of the collar portion 25 and defining an annular groove 40 in cooperation with one end 24a of the cylindrical portion 24.

The engaging portion 27 consists of a taperec-31 surface pcrt-ion 27a formed from the outer c-rc,-,m.ferent-4al surface of the p-ro-l-rude--" portion 26 to a lowe-r- surface oil the collar'portion 25 ard-a cylindrical surface portion 27b in coi - Itinuous with the tapered surface portion 27a and reachinc the lowe-r surface of the collar portion 25.

The bearing body 22 includes a cylindrical bearinc portion 28, an annular inner collar portion 29 forr-,e--'.' integrally with an upper end of an inner circur.-.'úerential surface of the bearing portion 28, an annular outer collar portion 30 formed integrally with the upper end of the outer circumferential surface of the bearing portion 28, an annular suspended portion.311 formed integrally with the outer circumferential edge of the collar portion 30, an engaging hook portion 32 formed at a lower end of the suspended portion 31 and an annular 2 11 u=ze:- It 42 czaxia--,!v with the be=--n r:: r z _L on. 2 -, a t a 1 c -;,; e r s -- r f- a z e cf t---e c c 12. a r r, z: z:l -- - 3 _ and having an inner diazeter larger than an cuzer diameter of the annular lower lip portion 41 formed' tc an upper surface of the collar portion 25 of the casing 21.

The hook 32 consists of a tapered surface portion 32a corresponding to the tapered surface cc.-.stitutes the engaging portion 27 oil portion 27a that the casInc 21 and a cylindrical surface portion 32b in continuous with the tapered surface portion 32a and to the cyl--,'n--"---- 4ca'- surfacce pcrt-on 27b c' 27.

the engaging T - Lhe bearing 22 is fitted rotatably to the ns the hook portion 32 of the casing 21 by susne-.,-',e--^ port-,c:, 31 with the eneacing portion 27 c' the 21 and. by ra--;iallv overlapping an end of the upper lip per----cn 42 w- th the lower lip portion 41 of the casi= 21, whereby ticht seals are formed by the lect in the snap-fit portion and in the upper lab-ri,-.th ef and lower lip portions.

A plurality oil recesses 33 are formed radially at the upper surface of the bearing portion 28 of the bearing body 22, so that the thickness of the bearing body 22 is made uniform as much as possible by the recesses 33.

e= at a 34 are fo=..c-- th a: t.-.e lower surfaze c 1-he be=-2-c f the bearing bodRy 22 and each groc-ve 34 is portion 28 of formed radSially fro.m the inner circtr-,,f-ere--it-l'al surface to the outer circumferential surface, and the grooves 34 constitute an oil reservoir for grease or like other lubricant. The bearing portion 28 of the bearing body 22 is disposed wm-thin the groove 40 such that the lower surface of the be-aring portion 28 is slidably abutted against- the bottom face of the groove 40 of the casing 2 1 The slidino face defined with the lower s,-,r'Lace of the bearing portion 28 of the bearing body 22 and the bottom face of the groove 40 formed to the casing 21 slidably albuttinc aga-inst the lower surface is protez'.e-- aga-Inst the intrusion of dust or the like from the inner c---c-=..ferer. t-ial surface of the thrust bearing 20 by the labyrinth effect due to the tight seal formed in the snap-fit portion and in the overlapped portion between the upper and lower lip portions 42, 41 respectively.

Figure 10 illustrates an embodiment in which the second thrust bearing 20 described above is applied to a strut assembl,.,r A.

-1 d c-, f the cas-n- 21, the c-ter Y,indrical pzrtJon 24 of J-.tsur-face of the cylindrical 24 of the casing 21 is fitted into the aperture of the upper 1: the collar pc,-t.io.-i 25 spring seat 8, the lower surface o. of the casing 21 is abutted against the flat portion 10 of the seat 8 and the upper surface of the bearing body 22 is abutted against the mounting me=ber 5.

Exzlanat-,c.-, wIll be made sDecifically for one ' c present invention referring to Figures 11 through 11. - the accompanying drawings..

A thrust bearing 20 cc.-.,prises a cas,.nc 21 made of resIn and a bearing body 22 made of ,.e cas-.-g 21 includes a cvlindrical- portion 2,'2' a penetration aperture 23 being along a longitudinal direction thereof, an annular inner lower lip portion 43 disposed to an upper end surface of the cylindrical portion 24 and having an aperture of a diameter enlarging with a step from the penetration aperture 23, a large width collar portion 25 formed integrally with an outer circumferential surface at the 1 ed end of the cylindrical portion 24, an annular protrud - - 2E - 2 6 f n = e c: r al l. v w an outer 1 2 5, an c f tIn e c c l, I a r p c: r c _n portion 27 formed to az., outer surface of the protruded portion 26 and an annularr outer lower lip portion 44 coaxially formed with the penetration aperture 23 at an upper- surface oil the collar portion 25 and defining an annular groove 40 in cooperation with. the annular inner lower lip portion 43.

The en-a-ing portion 27 consists of a tapered tl-t% surface portion 27a formed from the outer circujn-fere.-.t-Jal surface cf the portion 26 to the!owe.

r-irc=,.feren-t-ia'L. surface of the collar portion 25 and a cylindrical surface portlon 27b in continuous with the _tapered surface portion 27a and reaching the lower surface of the collar portion 25.

The be-=r-Lnc 22 includes a cv1indrical bearin:: 28, an annular inner collar portion 29 forr.-e-- integrally with an upper end of an inner circumferential surface of the bearing portion 28, an annular inner upper lip portion 45 protruding downwardly in continuous with an inner circumferential edge of the collar portion 29 and having an inner diameter equal with the diameter of the penetration aperture 23 of the casing 21 and an outer diameter smaller than the inner diameter of the inner lower lip portion 43, an annular outer 11 2-1 1 ith an u-:.zer enz az J0 w.'.. the cuzer c -- rc:---L-0 erential suri- a =e cf- z'l,.e be ar == -oz r t i

28, an a=ular suspended' portion 31 f ornted int-eg, rally with an outer edge of the collar Portion 30, an engaging hook portion 32 formed at a lower end of the suspended portion 31 and an annular outer upper lip portion 46 formed coaxially with the bearing portion 28 to a lo-wer surface of the collar portion 30 and having an inner dia--reter greater than an outer diameter of the outer lowe-r lip portion 44 formed to the upper surface of the collar 25 of the cas--',-c 21.

1 a tapere,- The hook portion 32 consists c.

s'ace portion 32a corresponding to the tapered surface ur. portion 27a that constitutes the e.-igac-4nc portion 27 cf the casing 21 and a cylindrical surface portion 32b in -a-jere.' surface portion 32a and the t to the cylindrical surface portion 27b of the enga--n- portion 27.

The bearing body 22 is fitted rotatably to casing 21 by snap-fitting the hook portion 32 of the suspended portion 31 with the engaging portion 27 of the casing 21 and by radially overlapping the ends of the inner and outer upper lip portions 45, 46 respectively with the inner and outer lower lip portions 43, 44 of the casing 21, whereby tight seals are formed by the 1 A plurality oil: recesses 33 are formed radially at the unper. surface of the bearing portion 28 of the bearing body 22, so that the thickness of the bearing body 22 is made uniform as much as possible by the recesses 33. eac. at a A plurality of grooves 34 are for-me, Il. 1 c-ircxL-nferenlk--ial p-Ltch at the lower surface of the bearing J= b--1, 22 and each grc-,.?e 3 2E of the be-ar- z fer fcrr,-.ed radJally f.rom the inner circum -ential surface to the outer circ=nferential surface, and the grooves 3 -e an oil reservoir for grease or like ot constitu41 l. h-her lubricant. The bearinc portion 28 of the bearing bol--y 22 is disposed with.in the groove 40 such that the lower pc::t-Jor., 28 is slidably abutte.' rst the bottom surface of the groove 40 of the casino 21.

The sliding face defined with the lower surface of the bearing portion 28 of the bearing body 22 and the bottom face of the groove 40 is protected against the intrusion of dust or the like from the inner and the outer circumferential surfaces of the thrust bearing 20 by the labyrinth effect due to the tight seals formed in z j in the overlapped por-l--,cn between i.--ne:- upper and low=-:' lip- r)crz-lcns 45, 43 and' the i overlapped porzIon between the outer upper and lower l:p-.rtions 46, 44 respectively.

Figure 15 is a longitudinal cross sectional view illustrating another embodiment of the third thrust bearing according to the present invention.

In this embodiment, an engaging portion 36 i s formed: to the inner circum.fe.-e.-it-'Lal surface of the inner lower lip portic.n 0 of the casing 21, while an engaging ' t- the outer circumferent.

hook 37 is for-me 'al surface of the inner upper lip portion 45 oil: the bearing body 22 in the aforementioned e=bodiment of the third thrust bearing. Both of the en caging portion 36 and the hook portion 37 are snap-fit to each other and fitted in a relatively rotatable manner.

Ficure 11-55 illustrates an eruDodliment in v;',-.-4ch one cf the third thrust bearing descried above is applied to a strut assembly A.

Specifically, the piston rod 2 of the strut 1 passes through the penetration aperture 23 in the cylindrical portion 24 of the casing 21, the outer circumferential surface of the cylindrical portion 24 of the casing 21 is fitted into the aperture of the upper spring seat 8, the lower surface of the collar portion 25 1 r-1 - 21 J_. th.e flat pcr--.-on 1C ace c t"-.e be=rnz bo- a=d sur: - 1. J. --- 22 is abutted against the ne-.-,ler 5.

Eor one Explanation will be ma-de specifically -h thrust bearing according to the embodiment of a four', I- - present invention referring to Figures 17 through 19 of the accompanying drawings.

A thrust bearing 20 comprises a casing 21 made of sv.-ithet-ic resin andS a bearing body 22 made of synthetic resin slidably fitted to the casing 21.

T1he casing 21 includes a cylindrical portion 24 a penetration aperture 23 being along a longitudinal direction thereof, a large width collar portion 25 formed' integrally with an-outer, circumferential surface at the end of the cylindrical J portion 26 forme.' portion 24, an annular protruded -er circumferential edge of the inte-prally w Lh an out collar portion 25, an engaping step 50 formed to the outer circtL-tifere,-itial surface of the protruded portion 26, a substantially cylindrical lower bearing portion 51 formed integrally with and protruded from an upper surface of the collar portion 25 and an annular ridge portion 52 formed in continuous with the inner circumferential edge of the bearing portion 51 and protruded from the end of the bearing portion 51.

d', C' ,.e bear body 22 cc=: issees a S' h=--7 t= centra-, 2------ =; az I - - rcrzic- a circular anerture 1-3 Ln coi7,,-,,un-4ca---,'on with the penetration aperture 23 of the casing 21, a cylindrical upper bearing portion 28 formed integrally with the lower surface of the disk-like portion 54, an annular inner protruded portion 56 spaced apart from an inner circu:-,lLe. -enlb-.ial surface of the bearing portion 28 by an an.nularr inner groove 55, protruded at a leac"Jre end J thereof from an end face of the bearing portion 28 a.= 'I- the c---,ular apertu fc--...e.-' in witl. -- re 52, an annular outer protruded portion 58 spaced apart fro.m an r outer circ.LL-rferential surface of the bearing portion 28 by an outer annular groove.57 and protruded at, a lead-Ing en.' thereof from the end face c'- the bearing portion 28 and an annular suspe-de,- portion 31 formed at an outer c-Jrc=..fere7.-.-'Lal edge of the disk-like portion 54 and havinc an. e,-gaging hook portion 32 at a leading end thereof.

The bearing body 22 is fitted rotatably to the casing 21 by snap-fitting the hook portion 32 of the suspended portion 31 with the engaging step 50 of the - the end face of the bearing portion casing 21 such thath. 28 is abutted slidably against the end face of the bearing portion 51 at the upper surface of the collar - S 1 2 5 a nd t'-"t e 5 anc, = outer are 'rcr.-, the end faces of 1 J- 1-4 the bearing portions 28, 51 respectively.

Since the sliding face between the end face c.L f- the bearing portion 28 and the end face of the bearing portion 51 is formed at a position higher than the upper surface 59 of the collar portion 25 by the combination of the casing 21 and the bearing body 22 and since the inner and outer protrusions 56, 58 of the bearing body 22 are dis,josed while being protruded from the sliding face, 4---us-cn c' dust or the like from the outside to the slidinc face can be prevented by the labyrinth effect due to the t-l9'.-.-- seal formed- in the inner and. outer cht circu--r,fere7.tial ences of the sliding face and the tseal formed: in the snap-fit portion between the bearing me-mber 22 and the casing 21.

---L:re 2,- i"llustrates an e--odment in %,fich the bearing 20 co=prising one em.bodiment of the fou---ki-i thrust bearina described above is applied to the strut assembly A.

Specifically, the piston rod 2 of the strut 1 passes through the penetration aperture 23 in the cylindrical portion 24 of the casing 21, the outer circumferential surface of the cylindrical portion 24 of the casing 21 is fitted into the aperture of the upper 1 11 - 33 th-e lower surface of the - aca',nst th-e fiat nor-::-cn a -u t I- ed -the seat 8 and: the bear- Jng body 22 is abutted aga-Jr.sz the mount mwbe r 5.

Explanation w'll be made specifically for one embodiment of a fifth thrust bearing according to the present invention referring to Figures 21 and 22 of the accompanying drawings.

A thrust bearing 20 comprises a lower casing 60 made of synthetic resin, an upper casing 61 made of resin a.-," a bearing piece 62 made of resin disposed w-,t','-.--n the upper and lower casings 60,61 The lower casing 60 includes a cylindrical portion 6 having a penetration aperture 63 being alc-2- a longitudinal direction thereof, a large width collar portion 65 formed integrally with an outer circ=,,--':eren-,-'i.al surface of the cylindrical portion 64 in a state one end 6'=a of the cylindrical portion 64 is protruded; therefrom, an annular protruded portion 66 formed integrally with an outer circumferential edge of the collar portion 65 and an engaging portion 67 formed to an outer circumferential surface of the protruded portion 66.

The engaging portion 67 consists of a tapered surface portion 67a formed from an outer circumferential -I 1 the protruded portion 6E to a lower surface of pcrtion 65 and a --.:rface ncrt--cn 67b in continuous w;th the tanere, surface vor6ion 67a and reaching the lower surface of the collar portion 65.

The casing 61 includes a disk-like flat portion 68, a circular aperture 72 formed at a center of the flat portion 68 and having the same diameter as that of the penetration aperture 63, an annular suspended portion 69 formed integrally with an outer the flat portion 68 and ar, circumferential edge ol I the d engag.ng hook portion 70 formec at a lower en. susnended- portion 69. The hook portion 70 consists o,. a tanered surface portion 70a corresponding- t'o the tapered surface portiio-. 67a constituting the engagIng portion 67 of the casing 60 and a cylindrical surface portion 70b in continuous with. the tapered surface portion 70a and correspond. ng to the cylindrical surface portion 67b of the e.-gaging portion 67.

The casing 61 is fitted rotatably to the casing 60 by snap-fitting the hook portion 70 of the suspended portion 69 with the engaging portion 67 of the casing 60, thereby a tight seal is formed by the labyrinth effect in the snap-fit portion.

The bearing piece 62 comprises an annular late having an inner aperture 62a of an inner diameter the casing 60.

A plurality of grooves 62b are formed radially from the inner azerture 62a to the outer circumferential surface alternately on both end faces of the bearing piece 62 at a phase difference of 30 degree with each other in the C4Lrcu:mferential direction, and the grooves 62b constitute an 041 reservoir for crease or like other Duh: ic a nt The bearring p4 ece 62 is disposed wit-11--in the casings 60, 62 such that the inner aperture 62a is - -1 ', --- a=,c-zer c th.e c-; and an Cuzer d-Lameter S=a"-ler inner diameter c:E the pr--tru,-^ed 66 of engaged with the outer circumferential surface of one end 6,;'=_ of. the cylindrical portion 64 and the both end faces J aga4nst the of the bearing piece 62 are slidably abutted - lower surface of the disk-like portion 68 of the casino -'I- _. surface of the collar portion 65 oil' the 61 and t-e u--re casing 6C respectively.

Figure 23 illustrates an embodiment in which one embodiment of the fifth thrust bearing according to the invention as described above is applied to the strut assembly A.

Specifically, the piston rod 2 of the strut 1 passes through the penetration aperture 63 of the cylindrical portion 64 of the casing 60 and the circular - - - e disk- - like -crz4 -n I:- of the cas -12 c- I- the 6.1 of tIne casinc: 60 is the i-,z-cer snri.-..o seat 8 and the into tne azerture o l b- lower surface of the ccIlar portion 65 of the casing 600 is abutted against the flat portion 10 of the seat 8, and the upper surface of the disk-like portion 68 of the cas.Lne 61 is abutted against the mounting member 5.' Explanation will be made specifically for one e-rLbodi-ien,t of a sixth thrust bearing according to the present invention referring to Figures 24 and 25 of the A thrust bearing 20 comprises a lower casing 60 mr-de of synthetic resin, an upper casing 61 made of synt"hetic resin ard a bearing piece 62 made of synthetic resir. disposed within the upper and lower casinos 61, 60.

The lo-v.,er casing 60 includes a cylindrical portion 64 ha,.,.-,-nc a penetration aperture 63 being along a long ' direction. thereof, a large width collar portion 65 formed integrally with an outer circumferential surface at the end of the cylindrical portion 64 in a state where one end 64a of the cylindrical portion 64 is protruded therefrom, an annular protruded portion 66 formed integrally with an outer circumferential edge of the collar portion 65, an engaging portion 67 formed to the outer circumferential J.1 3 7 - s u r f a z e c f th. -- r r c t:-u,-:, e d p -r t i -- n 6 6 a n d a: - la r. I c w =_:

th 4 - 1-,-,) 73 f=ed coax ally w-,b'., --e penetraz--n azert,..:re 63 at the upper surface of the ccilar portion 65 and defining an annular groove 74 in cooperation with one end 64a of the cylindrical portion 64.

The engaging portion 67 consists of a tapered surface portion 67a formed from an outer circumferential surface of the protruded portion 66 to a lower surface of the collar portion 65 and a cylindrical surface portion 67b in continuous with the tapered surface portion 67a and reaching the surface of the collar port-,--.-.

The casing 61 includes a disk-like flat portion 68, a circular a-ierture 72 formed, at a center of the disk-like portlon 68 and ha.ing the same dia7neter as that c.E the penetration aperture 63, an annular suspended inzecrally por-Li-,n Eq --h an outer circ,=,.fe:-- 1 the disk-like port J'no hook entIal e,-;::e c. tion 68, an engag portic.n. 70 for-med at a lowe.r end of the suspended portion 69 and an annular upper lip portion 71 formed coaxially with the circular aperture 72 at a lower surface of the disk-like portion 68 and having an inner diameter greater than the lower lip portion 73 formed to the upper surface of the collar portion 65 of the casing 60. The hook portion 70 consists of a tapered surface portion 70a corresponding to the tapered surface portion 67a f th 61' cons ti tuti.ng t:Ie eng; g port-Jor. 67 0.

a cyliza-ri-ca]. sur-face portic.n. 7w"-- 4-..

tapered' surface portion 70a a--.d corres-ponding to the cylindrical surface portion 67b of the engaging portion 67.

The casing 61 is fitted rotattably to the by snap-fitting the hook portion 70 of the port-'Lon 69 with the engaging portion. 67 of the a' by rad n3ially overlapping the end of the f the portion 71 w;.th the lower lip portion 73 o;-;herehy t---- seals are fo-.. I.ed by the effect in the snap-fit portion and in the upper and lower lip portions.

The.bearing piece 62 comprises an annular plate having an inner aperture 62a of an inner diamet-er greater than the ou--e-- diameter of one end 64a of the cylindr-cal portion 64 and an outer diameter smaller than the inner d-Lamet-er of the lower lip portion 73 of the casing 60.

A plurality of grooves 62b are formed radially from the inner aperture 62a to the outer circumferential surface alternately on both end faces of the bearing piece 62 at a phase difference of 30 degree with each other in the circumferential direction, and the grooves casing 60 suspended casing 60 upper lip ca='.-,; EC, labvrinth Z M 1 11 62b ccns-t.;'.tut=- an cil for grease or like cther The bearing piece 62 is disposed within the 1 60 such that the inner aperture groove 74 of the casIng 1 62a is engaged with the outer circumferential surface of one end 64a of the cylindrical portion 64, and the both end faces of the bearing piece 62 are slidably abutted against the lower surface of the disk-like portion 68 of : the groove 74 of the casing 61 and the bottom surface cl. the casing 60 respectively.

The S!_L' ng face c-' the bearing defined w-, h both end faces of the bearing piece 62, the lower surface of the disk-like p-ortion 68 of thercasing 61 and he bottom face of the groove 74 of-the casing 60 abutted slidably against the both end faces is protected against - of dust or the like by the lab...rinth eff ect the intrusio., due to tight- seals forr,-,ed in the snap-fit portion and in the overlapped- portions between the upper and lower lip portions 71, 73 of the casings 60, 61.

Figure 26 illustrates an embodiment in which one embodiment of the sixth thrust bearing according to the present invention is applied to a strut assembly A.

Specifically, the piston rod 2 of the strut 1 passes through the penetration aperture 63 of the cylindrical portion 64 of the casing 60 and through the on E& of -72 of the disk-Like PCr--- th e c:a=-= 6', the 6. of the czs--- 6C is n the ur,-Der sz- fitted -o -4.e azerture ol ?-ir.g seaz 8, the lower surface of the collar portion 65 of the cas'ng 60 is abutted against the flat portion 10 of the seat 8, and the upper surface of the disk-like portion 68 of the casing 61 is abutted against the mounting member 5.

ExplanatIon will be made specifically for one embodiment of the seventh thrust bearing according to the present invention referring to Figures 27a, 27b, 27c, 27d and, 28 of accompanying drawings.

7% thrust bearing 20 comprises a lower casing 60 made of syntlhetic resin, an upper casing 61 maze of thetic synthetic resin and a bearing piece 6.2 made of syn_ resin disposed within the upper and lower casings 61, 60.

The cas---. 601 includes a cylindrical p-ortion ha---'n:: a cenetrat tion aperture 63 being along a long4Z,u--2-Jnal direction thereof, an annular inner lower lip portion 75 disposed to an upper end face of the cylindrical portion 64 and having aperture of a diameter enlarging with a step from the penetration aperture 63, a large width collar portion 65 formed integrally with an outer circumferential surface at the end of the cylindrical portion 64 in a state where one end 64a of the cylindrical portion 64 is protruded therefrom, an t A 1 4 l, - 6 6 f c rm e -- 171 z =_ = r a 11 v w i t'--. a n of th, e c c 12. a r o - - z n m' 5, a n engaging portion 67 fc-,-.me,- to an outer circ=.. ferential :% Id surface oil the protruded portion 66 and an annular outer lower lip portion 76 formed coaxially with the penetration aperture 63 at an upper surface of the collar portion 65 and defining an annular groove 74 in cooperatic.r. with the inner lower lip portion 75. The inner diameter of the inner lower lip 75 is enlarged than that of the penetration aperture 63.

The p-r±4on 67 cons4sts c-lr a tapered surface portion 67a formed fro=. the outer circumferential surface of the protruded portion 66 to the lower surface of the collar portion 65 an., a cylindrical surface portion 67b in co.-n.-tinuous with the tapered surface portion 67a and reaching the lower surface of the collar portion 65.

The casing 61 includes a disk-like flat portion 68, a circular aperture 72 formed at a center of the disk-like portion 68, an annular inner upper lip 77 formed integrally with and extended downwardly fr.om the inner circumferential edge of the disk-'like portion 68 and having an outer diameter smaller than the inner diameter of the inner lower lip portion 75, an annular suspended portion 69 formed integrally with the outer 42 an a t a 1 c-w= r end of th e e n s a n c: h c -- k _p c n 7 0 f c ez:

suspended portion 69 and an annular outer upper lip portion 78 formed coaxially with the circular aperture 72 to a lower surface of the disklike portion 68 and having an inner diameter greater than that of the outer lower lip portion 76. The hook portion 70 consists of a. tapered surface portion 70a corresponding to the tapered surface portion 67a consti tu ting the engaging portion 67 of the casing 60 and a cylin-rical surface portion 70b in wIth. C1-,e tapere--' surface portion 67a a--.corresponding to the cvLin,-',.-ical surface 67b of the engaging portion, 67.

The casing 61 is fitted rotatably to the lo.;:er casino 60 by snapfitting the hook portion 70 of the suspended portien 69 w4Lth the engaging portion 67 of the casin2 6 a.n-; by razi-ally overlapping the ends of the inner upper lip portion 77 and the outer upper lip portion 78 with the inner lower lip portion 75 and the outer lower lip portion 76 respectively, whereby tight seals are formed by the labyrinth effect in the snap-fit portion, in the overlapped portion between the inner upper and lower lip portions and in the overlapped portion between the outer upper and lower lip portions.

11 ate havinc an. greater than the outer portion 75 and EELn outer diameter of the outer 60.

A plurality of grooves 62b are formed radlially fro:-.. the inner aperture 62a to the outer circumferential surface alternately on both end faces of the bearing piece 62 at a phase difference of 30 degree with each other in the c-rc.=..fere.-.-.ial d-rec-tion, and the grocves 62b constitute an oil reservoir for grease or like other lubricant.

The bearing piece 62 is disposed within the groove 74 of the casing 60 such that the inner aperture 62a is encaced with the other circumferential surface of one e:-.^ 64a cf the cylindrical portion 64, both end faces of the bearing piece 62 are slidably abutted against the lower surface of the disk-like portion 68 of the casing 61 and the bottom face of the groove 74 of the casing 60 respectively.

The sliding face of the bearing defined with the both end faces of the bearing piece 62, the lower surface of the disk-like portion 68 of the casing 61 and the bottom face of che groove 74 of the casing 60 abuttedp-e=e 62 cc------es an ane--t:,ure -2a of an i=er d--=--etc-r die-neter of the inner lower lip dia:,-,e-er z=aller tha.n the inner lower lip portion 76 of the casing - 10. 1- the of th.e d-ust cz the like from the outer c ircurnif eren tial surfaces of the bearinc piece 62 by the labyrinth effect due to the tight seals in the snap-fit portion between the casing 60, 61, in the overlapped, portion between the inner upper and lower lip portions 77, 75 and in the overlapped portion between the outer upper and lower liz) portions 78, 76 respectively Thle thrusz bearings shown in Figures 27b to 27d are variant embodiments of the seventh thrust bearing Eac1h. of the thrus-k bearings shown in Figures 27b to 27d has the same construction a; that of the of -the seventh thrust bearing showrn in Figure 27a, except that a position of the inner lower lip portion 75 is different from the position of the inner!c-wer lip porzion -75 in the e.--.,bod-Jme-,,t shown in figurle 27a.

In the variant embodiment shown in Figure 277b, the inner lower lip portion 75 is disposed or. the boundary between the cylindrical portion 64 and the collar portion 65.

In the variant embodiment shown in Figure 27c, the inner lower lip portion 75 is disposed on a portion of the collar portion 65, which portion is adjacent to 1 w 11 the boundary between rhe cyli=drical portion Eh and the collar portion ET In the variant embodiment show in Figure 27d, the inner lower lip portion 75 is disposed on a portion. of the collar portion 65, which portion is distant from the boundary between the cylindrical portion 64 and the collar portion 65.

Figure 29 is a longitudinal cross sectional view illustrating another eModiment of the seventh thrust bearing according to the present invention.

Specifically, in this embodiment, another engaging portion 80 is formed to the inner circumferential surfacy of the inner lower lip portion 75 of the casing 60, while another engaging hook portion 81 is formed to the outer circum.ferential surface of the upper lip portion 77 at the central of the casing 61 in the aforementioned eModiment of the seventh thrust bearing. Both of the engaging portion 80 and the hock portion 81 are snap- fit to each other in a relatively rotatably manner.

Figure 30 illustrates an embodiment in which one embodiment of the seventh thrust bearing according to the present invention is applied to a strut assembly A.

Specifically the piston rod 2 of the strut 1 passes through the penetration aperture 63 in the c- r-,.-al 1 f the casinc: 60 and n - 61= cl azerture 72 of tIne pc-r-tion ES' cf the porzicn 612 of the casinc 60 is f into the aperture of the upper spring seat 8, the lower surface of the collar portion 65 of the casing 60 is abutted against the flat portion 10 of the seat 8, and the upper surface of the disk-like portion 68 of the casing 61 is abutted against the mounting member 5.

Explanation will be made specifically for one e.-.'-od-4ment of the eighth thrust bearing according to the present inventi-cr, referring to Figure 31 to Figure 315 of the drawings.

A thrust bearing 20 comprises a lower casing, 81 made of synthettic resin, dn upper -casing 82 madle of synthel-ic res--n and a bearing piece 83 made of syntheticresin dispose-555 within the upper and lower casings 82, 81.

The casing 81 includes a disk-like portion 85 having at a central portion thereof a penetration aperture 8, is along a longitudinal direction thereof, an annular innermost lower lip portion 87 extending upwardly from an upper surface of the disk-like portion with an annular step 86 in continuous with the penetration aperture 84, an annular inner lower lip portion 89 protruding upwardly from the upper surface of the disk-like portion 85 so as to form an innermost S1 11 f I - 4 77 w th. the 1 ip --er!c-w;- 'c= 9 -1 h 87, an a=,-,lar ol--- ar lip pcr-- protruding upwardly from the upper surface of the disklike portion 85 so as to form an inner annular groove 90 in cooperation with the annular irner lower lip portion 89, and an annular protruded portion 93 formed integrally with an outer circumferential edge of the disk-like portion 85 so as to form an outer annular groove 92 in cooperation with the annular outer lower lip portion 91.

The annular protrudecd portion 93 comprises a tapered surface pcrt--c,-, 93a extending do..-.,.vardly fr--:7, a top edge of an outer circuziferential surface thereo., and a tapered surface portion 93b connected continuously to the tapered surface portion 93a to thereby form an annular ancular-ridge portion in cooperation with the ta-iere" surflace portion 93a, and reaching an outer c,rc=..-Eere:-.t--a- s.-, rfa2:e of the disk-like portion 8S. face portions 93a, 93b forms an These tapered surf outwardly e.-.gaging portion.

A plurality of grooves 94 are disposed on a wall surface defining the penetration aperture 84. The grooves 94 are arranged along a circumference of the penetration aperture 84 and extend in an axial direction of the penetration aperture 84. The grooves 94 serve as an oil rese7voir for lubricant such as grease.

48 n.--.=-:-a-l 9.5 des-Icnates us=-= as a p-czrLI=---'ons 95 are on a lower surface of the disk-like Dortion 85 of the lower casing 81 so as to oppose to each other with respect to I,k - - the penetration aperture 84.

The upper casing 82 comprises a disk-like portion 97, a penetration aperture 96 formed at a tentral portion of the disk-like portion 97, and having the same diameter as that of the penetration aperture 84 of the lower casing 81, an annular innermost upper lip portion 98 --.--egral"y 'th and exter,,'4r.c frc-7.

an inner circ=.,.'e-.en-,ial ed-ge of the disk-like portion 97, an annular inner u-jDe-..-lip portion 100 extending downwardly from a lower surface of the disk-like portion 97 so as to form an innermost annular groove 99 in an axially outward direction in cooperation with the inne-.-r.cs-. upper lip portion 98, an annular outer upper lip pc:---n 1C2 extending, downwardly from the lower su-.0 rface of the disk-like portion 97 so as to form an inner annular groove 101 in cooperation with the inner upper lip portion 100, and an annular suspended portion 104 formed integrally with an outer circumferential edge of the disk-like portion 97 so as to form an outer annular groove 103 in cooperation with the outer upper lip portion 102.

q - cc:-,.-.prises a surface -1a disposet on an 1.= e r to: on 10 circtL-,,.lerenl.--4al surface of the a--irular suspended portion 104, and corresponding to the tapered surface portion 93a constituting the annular protruded portion 93 of the lower casing 81, and a tapered surface portion 104b connected continuously to the tapered surface portion 104a to thereby form an annular angular-recess portion in cooperation with the tapered surface portion 104a. These two tapered surface portions 109a, 104b form an encag-,ng hook portCion.

The upper casing 82 is fitted rotatably to the lower casing 81 by snap-fitting the engaging hook portion of the annular suspended portion104 with the engaging portion of the annular protruded portion 93 of the lower casing 81, by encaping the annular inner and outer upper lip 100, 102 with the annular grooves 88, 92 of the lo-,,.er casing 81, respectively, and by engaging the innermost annular upper lip portion 98 with the annular step 86 of the lower casing 81.

The snap-fit of the upper casing 82 to the lower casing 81 produces tightly sealed portions between the upper and lower casings 82, 81, which tightly sealed portions are caused by the labyrinth effect in the snapfit portion between the annular suspended portion 104 and bet-ween the inner upper lip rcr-b-o-.-.t i'i' and' the annular grcve SES, in the be--wee.-. the cuther upper lip portion 102 and the annular groove 92, a^ i Jnc portion between the innermost upper n, n. the engaz lip portion 98 and the annular step SEES.

The bearing piece 83 made of synthetic resin and receive- between the upper and lower casings t2, 8 1 comprises an a=.ul-ar plate having an inner dia..--.eter greater t-an the outer of the inner lower lip pc:-tz:.-. E^5 cf t--- ICY.'er casin= 81 and- an. cuter d-5a..,e-.er 1 i=er of the outer lower liz s m a e -- t an th.e,ncr''cn 9' cf the '-c,:er casing 81.

ofcrooves 105a and 10.5b are E3 SucIn that the grooves 105a are respez:z',.elv arrance-d- alo.-.c the circu:-..fe--ence of- the pieze E3 at- a phase difference of 30 degree w-th crooves 105b a,Dacent to the grooves 105a.

Lhe c.-oove-c 105a, 105b constitute an oil reservoir for lubricant such as grease as shown in Figure 33.

The sliding face of the bearing defined by both end faces of the bearing piece 83, the lower surface of the annular groove 101 of the upper easing 82 and the bottom. face of the annular groove 90 of the lower casing i 1 1 :z - a!, wi..,'r-'- lower surface and 1 - J. - respectively appainst the end faces, iiss protected against the intrusion of dust or the like from the inner and outer circumferential surfaces of the bea:.ing piece 83 by the labyrinth effect due to the tightly sealed portions formed' in the snap-fit portion between the annular. suspende,-; portion 104 of the upper casing 82 and the annular prc-.rude,-,' portion 93 of the lower casing 81, in the engaging portion between the inner upper lip portion 100 and the annular groove 88, in the engaging portion between t'.'--.e outer u.L---er 1,p portion 102 and the annular groove 92, and in the engaging portion between the annular innermost upper lip portion 98 and the annular step 86.

Fieure 34 illustrates an errbodiment in which one c-S the eighth thrust bearing according to the presen: invention is applied- to a strut asserbly.

Specifically the piston rod R of thestrut assembly passes through the penetration aperture 84 of the disk-like portion 85 of the lower casing 81 and the penetration aperture 96 of the disk-like portion 97 of the upper casing 82, the lower surface of the disk-like portion 85 of the lower casing 81 is abutted against the flat portion S, of the upper spring seat S, the protrusions 95 disposed on the lower surface of the disk- - 52 1 ke - in -he uZzer E ' b. 1 casinc ES are fitte--"- into fittinz apertures ES the f lat portion SI of the upper spring surface cf the di-sk-like portion 97 of the upper E2 beinc abutted against the mounting mem-ber cn the vehicle side.

106 5.

In the Figure 34, mark E indicates a coil sprinc, mark G be-.r.- a bvmpsto-per (rubber).

jel - - 1. 11 Ficure 311. is a long-4tu,-nal cross sectional h. U v el: anoth.er cl.' the eighth t. r st bearing ac:c:crd--.-c tc the present invention.

2 E e -p; t i res--ezt-,ve constitutions c.' the eighth thrust bearinc tion, a cylin-,,^.-ical pcrt-on azcc:-o to the present invent 85a is inte--ra-1-v w-1th an inner circumferential e,-ce cf the cas;-c 81, so that an interior space c.' the POrriOn 86a zonstitutes the penetration aperture 6.1. Except provision of the cylindrical portion 86_= the cc.-.s-.ruc-hion of this e,-..Lbodiment is same as in the e=ibodiment shown in Figure 31.

The cylindrical portion -86. zacilitates incorporation of the thrust bearing into the flat portion S, of the upper spring seat 5 of the thrust assembly.

1 4 - r, '., - The variant embodiment. of the bearing piece 83 shown in Figures 33 and 35 is illustrated with Figures 36 and 37. The bearing piece 83 comprises an upper annular lip portion 110a formed integrally with an inner peripheral edge - the bearing piece 83 so as to protrude upwardly from an the bearing piece 83, a lower annular lip upper end face c'. portion 110b formed integrally with the inner peripheral edce of the bearing piece 83 so as to protrude downwardly fro:- , a lower end face of the bearing piece 83, an annular the bearing groove 111a forme or, the upper end face o.

piece 83 s as tc5 the upper annular lip portion -I--- annular croove 111b formed on the lower end 110a, anotlAe. face of the bearing piece 83 so as to surround the lower annular lip portion 110b, and a plurality of grooves 112a and', 112b wInich are radially formed alternately on both end faces of the bearing piece 83 and communicate at inner ends thereof w-th the annular groove 111a, 111b, respectively. Each of the grooves 112a is disposed on the upper end face of the bearing piece 83, and each of the grooves 112b is disposed on the lower end face of the bearing piece 83. The grooves 112a are respectively arranged along the circumference of the bearing piece 83 at a phase difference of, for example, 30 degree with respect to the grooves 112b adjacent to the grooves 112a. Each of the grooves 112a is th each of the grooves 112b. The identical in depth wit annular groove 111 and the grooves 112a and 112b function as an oil reservoir for lubricant such as grease.

- 51 'i The bearing piece 83 described in accordance with Figures 36 and 37 can be properly applied to the thrust bearing set forth according to Figures 30 to 32.

Many widely different embodiments of the present invention may be constructed without departing from the spirit and scope of the present invention. It that the present inventi tC the specific descr- exce.=z as in the a 1 z 1 1 A th:-.us:: f or use w--t.-. an thrust-strut type suspension having a strut incorporating a shock absorber, a piston rod inserted in the s".-lock absorber, a mounting me:-,,ber for supporting the piston rod to the automobile body, and an upper spring seat loosely engaging the piston. rod, the mounting member and the upper spring seat having opposed, substantially planar lining an an- surface offset from each other and de.,ula.

space between them, said bearing being adapted to be rece,-,-e-3 4- the a=ular space between the upper sprinc seat and the mount-Ing me=ber a.nd adapted to rece."ve the P-%St---i rod therethr cuch, said bearing comprising:

i n a n.

a lower cas.ng r.-.a-:,e of synthetic res- hav--,g a -1unc:

axis, said lower casine in- --5:-J-a' porzion '-av-'ng a subszan--ia-ly a cy in- -- _ 1, -L - pjl.a-p-r up-per- surfaze, a lower surface, an outer circumferential surface, and a penetration aperture of circular cross-secction coaxial with said longitudinal axis of said lower casing, said penetration aperture being adapted to receive the piston rod of the suspension therein; and a collar portion extending outwardly from and formed integrally with said outer circumferential surface of said cylindrical portion, said collar portion having - 31' - 4.3 ar s,---ant-.ally planar upper a-nd lower s--,r4-azes and outer sur-f-ace, said lower surfac:e cf, Said collar portion be'Lr,-:, ao-apte--" to natingly engace tA--e upper surface of the upper spring seat of the suspension, and said collar portion including an annular inner lower lip portion extending upwardly from said upper surface of said collar portion coaxially with said longitudin?.1 axis of said lower casing and formed integrally with said upper surface of said collar portion, said inner lower lip portion having a distal end offset from said upper surface c-' said ci:ilar portion, said collar portion further including an annular protruded portion extending upwardly from said upper surface of said collar portion in-,-ec:r-ally,with- said outer circumferent and formed tial surface of said collar portion, said protruded portlon having an outer circumferential surface and an outwardly exten--nz:: en-jaging p--rtion or, said outer circ.=..-ferer-.ial surface of said protruded portion, and said collar- portion further including an annular outer lower lip portion extending upwardly from said upper surface of said collar portion coaxial with said longitudinal axis of said lower casing and defining an inner annular groove in cooperation with said inner lower lip portion and an outer annular groove-with said protruded portion, said outer lower lip portion having a 1 11 distall end offsei fr= sa-dd upper surface of said collar portion, and said' i=ner a=ular groove ha-jjr-,-, a surface, said die-meter "dV' inner lower lip pcrtior, having an ou-ker and said outer lower lip portion having an inner d-,'a--nelt--er "d2", respectively, 11d111 being smaller than "d2"; an upper casing made of synthetic resin and having a longitudinal axis, said upper casing comprisi ng a disk-like portion having substantially planar upper and lower surfaces, an outer circumferential edge, a circular aperture at the center thereof coaxial wIth. said' longitudinal axis of said upper casing and defining an inn er circ,.i-.nferen-.ial edge, an annular outer upper 1ip e, id' i n g d - portion ext -;.-.wa.-diy fro,--.i said lower surface os'd d 21 L ai, --k-like coaxial with said longitudinal i xIs of said upper casing, and an annular suspended portion extend4ng downwardly from sa-d lower surface of said pcr-,-i--n and formed integrally with said outer c-rcL.,--nferer.-lial edge of said disk-like portion and fining an outer annular groove in cooperation with said del outer upper lip portion, said upper casing further including an annular inner upper lip portion extending downwardly from said lower surface of said disk-like portion coaxial with said longitudinal axis of said upper easing and formed integrally with an inner -!> 5. - -,:Crt;on = =4d A;-'K-14 C_ _k=defi7l'-ng, an i-n-ner annular croove in coc.:--=ration wi ann-ular outer upper lip portion., said upper surface of t% 3apted to mat said disk-like portion being ad Lingly engage the lower surface of the mounting member of the suspension, said circular aperture being adapted to receive the piston rod of the suspension therein, said inner and outer upper annular lip portions each having a distal en.,' offset from. said lower surface of said disk like portion, and said suspende', portion having a distal a offset frc.-.. said, 1-o-,,jer surface of said disk-like portion and^ an engaging hook portion formed at said -ion with said engaging portion of distal end for cooperat said protruded. portion; ana : synthet in and a bearing piece made of k-ic res cor.m-.is-4ng,,, an annular pli-ate having upper and lower fa- an. inner diame- t_han "di" an-- sur es an;-er creater an outer d--a:7.eter less than "d2", said bearing piece being received in said inner annular groove of said lower casing; said hook portion of said suspended portion of said upper casing being snap-fitted with said engaging portion of said protruded portion of said lower casing to define a snap-fit portion, whereby said upper casing is fitted rotatably to said lower casing, said upper surface 21 11 - -5- - d bea:-J-.-= z-'eze abuzzed a-;=2.-.=z cf sa - - t, lower surface c-0 said said dIstal C c,- said inner and outer upper Lip portions being overlapped radially with said dist-al ends cif: said i=ner 1, and outer lower lip portions, respectively, to define inner and outer overlapped portions, said lower surface of said bearing piece being slidably abutted against said bottom surface of said inner annular groove, whereby tight seals are formed at said snap-fit portion and said inner and outer overlapped portions.

2. -.,-e bearing as claimed in claim 1, in which- A - 4 sa'd cylind-cal portion further has an annular innermost I lower lip portion extend'ng upwardly from said upper : sa- surface of 4d cylindrical portion adjacent and off'set sten-w-se fro-, sai'l pe-etration aperture, said innerm-st lower lip pcrtion defining a cylindrical aperture having a dia:--e-:er slight'lly greater than that of said penetration apert-ure and defining an innerrost annular groove in cooperation with said inner lower lip portion, said innermost lower lip portion having a distal end offset from said upper surface of said cylindrical portion, said distal end of said innermost lower lip portion being overlapped radially with said distal end of said inner upper lip portion, said disk-like portion further has an innermost upper lip portion extending downwardly from a 6 r', - 4 ' '-=e-^ of said disk-like portion ant J.

in.ner circumferential e.-J,-,,e of said and defining an innermost a.-=-, ular groove in cooperation with said inner upper lip portion, said innermost upper lip portion having a distal end offset froir. said lower surface of said disk-like portion, said distal end of said innermost upper lip portion being Jially with said distal end of-said overlapped ra. innermost lower lip portion.

3. The bearing, as claimed in clair. 2, in whicIn. said lower s--,r.0Laz-e of said collar portion is subs tant ial Iv offset fro,-, said lower surface of' said cylin,--^.-ical portion.

4. T1he bearing. as claimed in clairl, 2, in which said lower surface of said collar portion is substant-ally coplanar with said lower surface of said portion.

5. A thrust bearing for use with an automobile thrust-strut type suspension having a strut incorporating a shock absorber, a piston rod inserted in the shock absorber, a mounting member for supporting the piston rod to the automobile body, and an upper spring seat loosely engaging the piston rod, the mounting member and the upper spring seat having opposed, substantially planar surface 11 offset from each other and defining an annular space between them, said bearing being adapted to be received in the annular space between the upper spring seat and the mounting member and adapted to receive the piston rod therethrough, said bearing comprising a lower casing made of synthetic resin, having a central aperture and an outer upwardly extending engaging portion, an upper casing made of synthetic resin, having a central aperture and an outer downwardly extending suspended portion snap fittingly engaging said engaging portion, and a bearing piece between the lower and upper casings, being separate or on one of the casings.

6. A thrust bearing according to claim 5 including upper and/or outer annular ribs extending respectively upwardly from the lower casing and downwardly from the upper casing and being overlapped to provide seal(s).

7. A thrust bearing constructed and arranged substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

-t-IJL -

Claims (6)

1. AMENDMENTS TO THE CLAIMS HAVE BEEN FILED AS FOLLOWS.

   A thrust bearing for use with an automobile thrust-strut type suspension having a strut incorporating a shock absorber, a piston rod inserted in the shock absorber, a mounting member for supporting the piston rod to the automobile body, and an upper spring seat loosely engaging the piston rod, the mounting member and the upper spring seat having opposed, substantially planar surface offset from each other and defining an annular space between them, said bear-ing being adapted to be received in the annular space between the upper spring seat and the mcunt-5ng me=ber and adapted to receive the piston rod therethrouch, said bearing comprising: a lower casing made of synthetic resin and having a longitudinal a-xis, said lower casing includ-Jng: a cylindrical portion having a substantially planar upper surface, a lower surface, an outer circumferential surface, and a penetration aperture of circular cross-section coaxial with said longitudinal ax.4s of said lower casing, said penetration aperture being adapted to receive the piston rod of the suspension therein, said cylindrical portion further having an annular innermost lower lip portion extending upwardly from said upper surface of said cylindrical portion adjacent and offset stepwise from said penetration aperture, said innermost lower lip portion defining a cylindrical aperture having a diameter slightly greater than that of said penetration aperture, said innermost lower lip portion having a distal end offset from said upper surface of said cylindrical portion; and c f a collar portion extending outwardly from and formed integrally with said outer circumferential surface of said cylindrical portion, said collar portion having substantially planar upper and lower surfaces and an outer circumferential surface, said lower surface of said collar portion being adapted to matingly engage the upper surface of the upper spring seat of the suspension, and said collar portion including an annular inner lower lip portion extend ing upwardly from said upper surface of said collar portion coaxially with said longitudinal axis of said lower casing and formed integrally with said upper surface of said collar portion, said inner lower lip 1Dortion havina a distal end offset from said umr)er surface of said collar portion and defining an innermost annular groove in cooperation with said innermost lower lip portion, said collar portion further including an annular protruded portion extending upwardly from said upper surface of said collar portion and formed integrally with said outer circumferential surface of said collar portion, said protruded portion having an outer circumferential surface and an outwardly extending engaging portion formed on said outer circumferential surface of said protruded portion, and said collar portion further including an annular outer lower lip portion extending upwardly from said upper surface of said collar portion coaxial with said longitudinal axis of said lower casing and defining an inner annular groove in cooperation with said inner lower lip portion and an outer annular groove with said protruded portion, said outer lower 111D portion having a distal end offset from said upper surface of said collar portion, and said inner annular groove having a bottom surface, said inner lower lip portion having an outer diameter "dl" and said outer lower lip portion having an inner diameter "d2", respectively, 'Idl" being smaller than I'd2 "; an upper casing made of synthetic resin and having a longitudinal axis, said upper casing comprising a disk-like portion having substantially planar upperand lower surfaces, an outer circumferential edge, a circular aperture formed at the center thereof coaxial with said longitudinal axis of said upper casing and defining an inner circumferential edge, an annular outer upper lip portion extending downwardly from said lower surface of said disk-like portion coaxial with said longitudinal axis of said upper casing, and an annular suspended portion extending downwardly from said lower surface of said disk-like portion and formed integrally with said outer circumferential edge of said disk-like portion and defining an outer annular groove in cooperation with said outer upper lip portion, said upper casing further including an annular inner upper lip portion extending downwardly from sa-d lower surface of said disk-like portion coaxial with said longitudinal axis of said upper casing and formed integrally with said lower surface of said disk-like portion and defining an inner annular groove in cooperation with said annular outer upper lip portion, said disk-like portion further having an innermost upper lip portion extending downwardly from-said lower surface of said disk-like portion and formed integrally with said inner circumferential edge of said disk-like portion, and definina an innermost annular groove in cooperation with said inner upper lip portion, said innermost k k - i-l - upper lip portion having a distal end offset from said lower surface of said disk-like portion, said upper surface of said disk-like portion being adapted to matingly engage the lower surface of the mounting member of the suspension, said circular aperture being adapted to receive the piston rod of the suspension therein, said annular inner and outer upper lip portions each having a distal end offset from said lower surface of said disk-like portion, and said suspended portion having a distal end offset from said lower surface of said disk-like portion and an engaging hook portion formed at said distal end for cooperation with said engaging portion of said protruded portion; and a bearing piece made of synthetic resin and comprising an annular plate having upper and lower surfaces and an inner diameter greater than "dl" and an outer diameter less than "d2", said bearing piece being received in said inner annular groove of said lower casing; said hook portion of said suspended portion of said upper casing being snap-fitted with said engaging portion cf said protruded portion of said lower casing to define a snap-fit portion, whereby said upper casina is fitted rotatably to said lower casing, said upper surface of said bearing piece being slidably abutted against said lower surface of said disk-like portion, said distal end of said innermost upper lip portion being overlapped radially with said distal end of said innermost lower lip portion to define an innermost overlapped portion, said distal ends of said inner and outer lower lip portions being overlapped radially with said distal ends Of said inner and outer lower lip portions, respectively, to define inner and -WO- outer overlapped portions, said lower surface of said bearing piece being slidably abutted against sa,;d bottom surface of said inner annular groove, whereby tight seals are formed at said snap-fit portion, said innermost overlapped portion, and said inner and outer overlar)r)ed portions.
2. 2. A bearing as claimed in Claim 1, in which said lower surface of said collar portion is substantially offset from- said lower surface of said cylindrical iDortion.
3. 3. A bearina as cla-i--ed in Claim- 1, in which said lower surface of said collar portion is substantially coDlanar with said lower surface of said cvl-indr-4ca--, nortion.
4. 4. A bearing as claimed in claim 1, 2 or 3, in wtLich said bearing piece has one annular groove formed on an uDper end face of said bearing piece so as to define an upper annular lip portion along an inner peripheral edge of said bearing piece, a -olurality of radial grooves radially formed on said upper end face and tina at inner ends thereof with said one communicat annular groove, the other annular groove formed on a lower end face of said bearing piece so as to define a lower annular lip portion along said inner peripheral edge, and a plurality of the other radial grooves radially formed on said lower end face and communicating at. inner ends thereof with said other annular groove, said radial grooves and said other radial grooves being arranged alternately one by one along a circumference of said bearing piece.

   j 1 1
5. 5. A thrust bearing constructed and arranged substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

   published 1992 at The Patent Office. Concept House. Cardiff R-ad Newpon ClkenT NPq I RH Further eopit, be irczl Sales Branch. Unit
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