CA2182732A1

CA2182732A1 - Plain bearing

Info

Publication number: CA2182732A1
Application number: CA002182732A
Authority: CA
Inventors: Noel Francis Sheedy
Original assignee: Individual
Current assignee: Plastic Bearings and Housing Australasia Pty Ltd
Priority date: 1994-02-08
Filing date: 1995-02-08
Publication date: 1995-08-17
Also published as: JPH09508692A; WO1995022011A1; EP0870120A4; EP0870120A1; US5885006A; BR9506738A; CN1145107A; NZ279471A; MX9603253A

Abstract

A bearing including an inner bearing means (1) having an annular peripheral bearing surface (2), an outer bearing means (6) coaxial with the inner bearing means (1) and having an inner annular bearing surface (8) and at least one set of intermediate bearing means (9) including a bearing ring (10) having an annular inner bearing surface, an annular outer bearing surface (11, 12) and bearing bush means (13, 16) rotatable mounted about the inner bearing means (1) and rotatable with respect to the bearing ring (10) and outer bearing means (6) the bush means (13, 16) providing a bearing surface (15) adjacent the inner bearing surface of the bearing ring (11) and providing a bearing surface (17) adjacent the outer bearing surface (12) of the bearing ring (10).

Description

wo gS/22011 PcT/~1T~ ~
PLAIN BEARING 2 1 ~3 2 7 3 2 The invention relates to bearings and bearing a Conventional roller bearings consist of an inner race member an outer race 5 member and roller balls held between inner and outer races by a cage or flanges.
Various types of plain bearings are also known in which rolling elements are replaced by a plastic bush. Some plain bearings of this type are able to operatewithout a lubricant however plain bearings generally suffer from the limitation that the bearing members became fused at high speed and/or under high loads.
Despite the improvements in plain bearings there is need for such a bearing which has a longer service life and/or is able to operate under more severe conditions such as high loads or at high speed for prolonged periods.
According to the present invention there is provided a bearing including an inner bearing means having an annular peripheral bearing surface outer bearing means having an inner annular bearing surface and at least one set of i"t~ r" - bearing means including a bearing ring having an annular inner bearing surface and an annular outer bearing surface and bearing bush means rotatably mounted about the inner bearing means and rotatable with respect to the bearing ring and outer bearing means the bush means providing a bearing surface adjacent the inner bearing surface of the bearing ring and providing a bearing surface adjacent the outer bearing surface of the bearing ring.
The i, " bearing means of the bearing of the invention includes at least one bearing ring and bush means. The bush means may be in the fonm of a single bush member ~u~ Jliaill~ two bush rings one inside and one outside of thebearing ring and c~,~"e~.tt:d by a web extending adjacent the end of the bearingring. It is particularly preferred however, that the bearing bush means include an inner bush member rotatably mounted about the inner bearing means and rotatable with respect to the bearing ring and having a peripheral bearing surface adjacent the inner bearing surface of a bearing ring and an outer bearing bush ~, --r ~ ~ ~ ~ 2 2 t 8 2 7 3 L
rotatably mounted about the bearing ring and having an inner bearing surface adjacent the outer bearing surface of the bearing ring.
.
The bearing ring may be integrally fommed with the inner or outer bearing means 5 however it is preferred that it be rotatable with respect to each of the inner and outer bearing means.
In a preferred form of the bearing of the invention one of the inner and outer bearing means includes an annular locating flange and an radial bearing surface 10 disposed on each side of the locating flange and the other of said inner and outer bearing means includes a pair of collars one collar extending on each side of the flange and the bearing includes two sets of i~ didL~ bearing means disposed between facing sides of the collars and locating flange one set on each side of the flange.
Preferabiy one of the collars, referred to a the thrust collar, is l~llluvàul~ from the bearing means cu, I I,UI i~i~ Iy the pair of collars such that the other bearingGulll,uull~l,ts may be removed and lc:à,~._."uled a is required. It is preferred the thrust collar is d~laulldble from the race provided with a collar at one end of the 20 race a bearing surface and a portion for receiving the thrust collar at the other end of the race. The portion for receiving the thrust collar may be recessed; the recessed portion being on the inner surface when the outer bearing means includes said collars and on the outer surface when the inner bearing means includes the collars. The thrust collar receiving portion may also be provided with 25 a radial groove to allow the end of the thrust collar receiving portion to bedeformed to retain the collar. All~ cly, the thrust collar and collar receiving portion may comprise Cul I l::a,uul Id~ 19 threaded portions.
The locating flange, which is preferably present on the inner surface of outer 30 bearing means, may be continuous or discontinuous and in the form of circul"' t:" 'Iy spaced tabs or the like. The locating flange may be in a variety of sections or shapes such a square rectangular, curved, dovetailed, bevelled or WO 95/22011 PCT/AT'gS.~

2 1 g 2 7 3 2 the like. Preferably the flange has ess~" 'Iy parallel sides and is disposed at right angles to the axis.
In this preferred fomm of the invention the illLt:llllt:did~ bearing means are typically 5 located each set in a recess or chamber defined between bearing surFaces of the inner or outer bearing means and the facing sides of each collar and the flange.There may be two or more recesses separated by a locating flange projecting from either the flrst or second bearing means and two or more bush members and/or bearing rings may be located in each of the recesses. For example, two 10 bearing rings may be coaxially arranged and separated from each other and from the inner bearing means by bushes.
The inner bearing means of the present invention most preferably includes an annular inner bearing surface and a pair of collars one at each end of the race. 15 The inner bearing means is preferably located within the outer bearing means such that the collars of the inner bearing means are in face to face It:ldliUI~slli,U
within an inwardly disposed flange on the outer bearing means. One of the collars is preferably a thrust collar adapted to be ,t:",oval,ly c~""eutt:d to the inner bearing means to enable an annular outer bearing means, annular bearing 20 ring and bearing bushes to be removed from and ass~",Ll~d about the bearing surFace of the inner bearing means.
The inner bearing means may include a bore for receiving a shaft or the like. The bore may be of any suitable shape for example it may be of circular, oval, 25 triangular, square, h~.dyulldl, rectangular or other configuration. Further, where the inner bearing means includes a bore the bore may be tapered between one and the other and may include a spline, gear teeth, it may be serrated or include other means for engaging a drive shaft or the like.
30 Where the inner bearing means includes a bore for receiving a shaft or the like the inner bearing means may be in the fomm of a sleeve and include axially extended portion which includes means for fixing the bearing to the shaft. The axially extended portion may include one or more holes for receiving a grub screws or may be c~ t~i..ldble and be provided with constructor means adapted to urge the uull:.tliuldL)le portion into locking ~l~ydy~lllelll with the shaft.
5 The inner race portion of the inner bearing means means may be provided with athreaded portion to engage a culle~Jo~ldillyly threaded thrust collar. In this form, the thrust collar may also include an additional annular flange having a bore c~"t::".ol,.li"g to an inner race bore, and having a threaded radial aperture therethrough to receive a grub screw or the like. Allelll "~_ly, the thrust collar 10 may be provided with means for engaging an annular eccentric collar having anaperture capable of receiving a grub screw or the like for fixing the bearing to a shaft located in the bore. In another alle", ' I form, the inner bearing means comprises an extended portion in the form of an annular axial flange. This axialflange may also have an aperture therein suitable to receive a grub screw or the15 like, for securing the bearing to a shaft or the like.
The bush members and the bearing ring of the ill~,.llled;~t~, bearing means are typically are coaxial and preferably there are two coaxial sets of i,.'~.", " ' bearing means each set c~"".,i~i"g at least one i"' ",~ ' ' member and at 20 least two bearing bushes and being located one series in each of two recessesdefined by inner and outer bearing means.
It is preferred that the bearing ring is of smaller axial width than at least one and preferably two of the bearing bushes. Further, the Applicant has found that 25 operation of the bearing is ~iy"~ ,'~ improved where at least one of the bearing bushes in each set of il.'~,.llledidte bearing means includes one or more lips which cooperate with the bearing ring to retain the ring spaced apart from the facing sides of the flange and collar.
30 The bushes may have a lip adjacent one edge thereof and extending adjacent anedge of the bearing ring thereby preventing the bearing ring from directly engaging the inner or outer bearing members. Preferably each of the bearing WO 95122011 PCT/~` _ 5 2 1 8 ~ 7 3 2 bushes has a lip and the bearing bushes adjacent the inner and outer circumference of the bearing ring cooperate such that the respective lips are located adjacent opposing ends of the i, ' ", - " ' bearing ring.
5 In the most preferred ~ I,odi,,,t:"l one of the lips radiate from adjacent the side of the inner bearing bush and the other lip is intemally disposed adjacent the opposite side of the outer bearing bush and the flanges coact to provide alignment of the ring and to provide axial bearing surfaces between the bearing ring and inner and outer bearing means. Radiating grooves circ~",'~
10 spaced on the outer face of the bush lips are also preferred and are believed to aid in heat ~" , " , and enhance the pe, ru", Idl ,ce of the bearing.
The bearing of the present invention may be used as wheel bearings for any type of vehicle, such as motor cars, motor cycles, tractors, bicycles, and trucks or the 15 like, and also tractors, bicycles, and trucks or the like, and also trailers of any type such as caravans, and boat or car trailers or the like. The bearing of the present invention may also be used directly as a wheel, as a surface levelling or finishing roller, or as any other forrn of a direct load carrying rolling member in a vehicle, agricultural illl~.l~lllt:llL orthe like.
In another ~",~o~i",~"~ the bearing of the invention is in the fomm of a cam follower wherein the first bearing means comprises an inner race stud together with a thrust collar. The inner race stud may be similar to a conventional bolt,having a head, an axially adjacent locating shaK portion providing a peripheral 25 bearing surface and a threaded shaK portion axially adjacent to the locating shaK.
The head if the bolt may define the inner race collar and the threaded shaK may receive a thrust collar which may include a coope, " ,9 thread in its inner circumference or the thnust collar may be secured by a threaded locking nut. Thethnust collar may take the fomm of an annular washer or the like.

WO 95/2201~ ` j . PCI/AU95/00058 1~
2 1 ~ 27 3 ~

The bearing of the invention may further comprise a housing for receiving the outer bearing means such as a pillar block housing two or more hole flange housing.
5 It will also be u,,.l~r~Luod by a person skilled in the art that the extemal surface of the outer bearing means may be of any cross 3c~,tiull. The surFace may be cylindrical, convexly or concavely curved, tapered, conical or fnl~luu~,,iual, or any cu,,lLi, " ~s of shapes, de~el)de"L upon specific requirements and intended use. For example, the bearing means may be s~L~Ld, ' 'Iy rectangular so that 10 the bearing itself may be rigidly secured to another member as required.
The outer bearing means may have a convex outer surface particularly a spheral section to enable the outer bearing means to be received into a housing having acul, t: ,po, Idi~ ,9 concave inner surFace whereby the outer bearing means may pivot 15 within the housing to allow it to align with a shaft or the like. Such a housing may be a pillar block housing, a 2- or more hole flange housing, a hanger type housing to allow the bearing to be used on a conveyor system for suspending articles from a conveyance line or may comprise sprockets or gears about its periphery.
20 The outer bearing means may also comprise protrusions such as sprockets gear teeth or tabs or the outer bearing means may have a peripheral annular groove toenable it to engage a belt or pulley. An outer bearing means including an outer surface having one or more V-shaped grooves may also be used.
25 The outer bearing means may include means for fixing the bearing for operaffon.
For example, where the bearing is to be used as a wheel hub it may include a radial flange with axial holes circ~",~.~"' 'Iy spaced about the radial flange for fastening the bearing to a wheel. The outer bearing means may also be shaped to act as a pillar block housing, or a 2- or more hole flange housing or the like.
One or more of the inner bearing means, outer bearing means, bush members and bearing ring may be split radially to fomm two annular portions with abu~ting .

7 2 ~ 8 2~'2U9S~o58 faces or may be split axialiy to form abutting semicircular portions which together form the annular bearing c~ ,ùl~"L. The split uulll~JOIIellla may include engaging portions such as cull~a,uullui.ly protrusions and recesses or wheFe thebearing is a self aligning bearing it may be preferred to use a split housing to5 enable portions of the housing to be aaac:l "L,led about the bearing. Alternatively a housing cUIll~Jliai"y a convex inner surface and a pair of didlllt~ Iy opposed slots may be used to allow the bearing to be inserted or removed from the housing when aligned with the slots and at right angles to the housing and to bepivoted within the housing to align with a shaft or the like.
In the bearing of the invention, the bearing bushes will, during operation, typically oscillate between a condition in which they are stationary with respect to the bearing suFface of smaller circumference and rotate with respect to the bearing surface of greater circumference and a condition in which they are stationary with 15 re~pect to the bearing surface of greater circumference and rotatable with respect to the bearing suFface of smaller circumference.
This oscillating action during operation, particularly when at least two bushes are present one inside and one outside the bearing ring, aiyll~ ,;ly improve the 20 operating life of the bearing and reduce wear of the bearing surfaces even a very high speeds and under light load.
The adjacent bearings surfaces of the bearing tof the invention are typically fomled of different materials. Thus the bearing surface of the lnner and outer 25 bearing means and bearing ring may be formed of one material while the bearing surfaces of the bushes are fommed of a different material. It is therefore particularly preferred in order to provide a long service life and the most effective ~:, Ful " Idl ,ue that the bearing bush means be constructed of a different material to the inner and outer bearing means and the bearing ring. r~re ,dLI~ one of the 30 group of ~u~ u~ selected from a first group consisting of the inner bearing means the outer bearing means and the bearing ring and a second group of consisting of the bearing bushes are fommed of a plastics material and the outer WO 95/22011 - pCTlA

of said first and second group of ..u,",uul,~"t~ is formed of metal. Most preferably each of the inner bearing means, outer bearing means and bearing ring is fommed of metal and the bearing bushes are fommed of plastics material.
5 The bush members of the present invention are preferably fabricated from a lll~llllopld~liu polyester resin and the inner and outer bearing means are preferably made from a corrosion proof metal such as stainless steel, aluminium or the like (although other metals may be used) may be coated wlth a hard material such as a titanium nitride or ceramic coating or the like. Additionally, all 10 of the C~"".ol~"ts may be made of plastics material, for example, the outer bearing means, the bearing ring and the inner bearing means may be of one plastics CCIIl,uO:-ltiù~ while the bearing bushes are of a different plastics material.
However, the outer and inner bearing means and bearing ring may be made of synthetic polymeric material, and the bush members may be made from a 15 conrosion proof metal or other metals which may be coated as above.
The bush members may be fabricated or moulded from a synthetic polymeric material or materials, such as PTFE, CTFE, PEEK, ACETAL, polyimide, poly(d",i~u,/i",i i~) ~"~t:i"~,~d or a partially crystalline, lll~::llllOpla:>liu polyester, 20 for example poly~ ,;lcne It~ plllll ' ' Materials from which the cu~ uuller,l~ of the present invention may be made include plastics, ceramics, glass, pure carbons, carbon fibres, graphite i"",,~y, ' ~' materials, kevlar, pl~spl~c,uus bronze or the like and may include cullll,i, " )s thereof. It will be ulld~l~lu~d by a person skilled in the art that the selection of the optimum material will be 25 d~ lll upon the particular,, " " 1 required of the bearing. For instance, where the bearing is being used in a conrosive ' ,,u~,ul~e~ due to the presence of a particuiar type of chemical, a material would be selected that was resistant to that type of corrosion. Similarly, if metals are used in the bearing, then the same cùl~sid~,dliu,,~ would apply. For instance, if rusting was not perceived to be a30 problem, mild steel may be used. All~lll.lti~cly, 316 stainless steel may be used, or, 41 û stainless steel may be used. Aluminium may also be used and the metals may be i~"~yl Idl~d with a polymer such as PTFE.

WO 95122011 pCrlAI~
' ~ 9 2 t 82732 As l~ illu~fvl~ described the inner bearing means may be included a sleeve adapted to receive a shaft and the sleeve may be provided with means for fixing the bearing to a shaft.
We have found that alignment of the bearing and p~ rurl, Idl ,ce of the bearing on a shaft may be enhanced if the sleeve has a u v"~l, iu1dul~ portion.
In a further aspect the invention provides a bearing for a shaft culllluli:~illg an 10 inner bearing means including a sleeve for receiving the shart and having an annular peripheral bearing surface and an outer bearing means rotatably having an inner bearing surfaoe mounted about the sleeve wherein the sleeve comprises an annular cOIlalli~ldLlt: portion and col,~l,i..tu, means for providing annular~ul lall iuliul~ to force the Col lal, i- ldule portion into locking ~ a~" ,~"1 with the 15 shart.
The annularly col,al,i~ldule portion preferably comprises a series of slots circu", ~ spaced about the sleeve and generally aligned with the axis on the sleeve so that the portions of the sleeve between the slots are radially 20 inwardly d~Fulllldul~ in response to a c~llatliuliOIl force from the ~ullalli~tu means.
The cu"~t~i. tur means typically comprises a bore adapted to be received on the sleeve and the sleeve and ~.O~atli~.tUI means preferably comprise cc,llt:~uo~
25 engaging mans such as threaded portions, to urge the c~llabiulul means along the sleeve so that the inner circumference of the CO~Iatli~tul means impinges upon the constructible portion of the sleeve to cause cOl,atliuliùl, thereof. The ~ullall i~ tur means is preferably a nut or threaded collar.
30 In a particularly preferred ~ uuu;,lle:lll the sleeve of the bearing extends beyond the race and the annularly col,~ idbl~ portion is located adjacent a protnuding end of the sleeve. In this ~, IlI.o~i, "~:"1 it is preferred that the slots extend from the WO 95122011 PcT/A

3 2 l 8 2 7 3 2 end of the sleeve in alignment with its axis and are circu", t:" 'l~ spaced to fomm a multiplicity of radially inwardly cl~""dLle segments. The COIIat~
means is receivable on the slotted end of the sleeve and the inner circumferenceof the Cu"~liutu~ means provides an inward force to the segments as it is urged 5 along the sleeve to thereby lock the sleeve onto a shaft. The cul ,~ dble portion of the sleeve preferably has an outer surface inwardly tapering toward the slotted end of the sleeve and the collatliutur means is adapted to be received onto and cooperate with the sleeve to impinge upon the tapered portion of the sleeve to force the cu"~tli..ldl~le portion inward. Al~ l J~IJ or in addition to the tapering 10 of the COIIatlilldul~ portion the inner surface of the COIIalli~.tul means may inwardly taper to provide a cor,a~,i, .i"~ force to the coll:,tli~ ~dule portion of the sleeve as it is urged onto the sleeve. The COI lat~ iU~ force may ~ ly be provided by a flange on the inner surface of an annular cul latl i~ lur means.
5 Preferably the sleeve and col,~tli-.~ul means comprise threaded portions whichcooperate such that relative ratation of the ---F- lg threaded portions urges the annular u ol la~ UI means along the sleeve and against the tapered surFace of the cul la~ d~l~ portion.
20 The slotted end of the annular COll;~ dul~ portion may lldll~ .. .l~ly taper and be threaded so that the collatli..ti~l- means impinges upon the tapered sides of the collatli- ~dL,I~ portion during relative rotation of the coll~liuti~ll means andCul 1~1l iu1dLle portion during relative ratation of the col l~ll iUtiUI I means and Cùllal~ ld~le portion. ~ 'y the sleeve may be threaded between the 25 slotted Cull~tli~ldul~ portion and the bearing race and the annular uullatliutiùl) means may comprise a threaded portion and a portion which impinges upon the tapered cull ,lli~.~dble portion.
The cùll~t,i~d~le sleeve is particularly useful in bearings including ill Ill 30 bearing means. The sleeve and ill;e:llll being means of the invention may comprise an annular flange and mutually abutting rings l~:a~ u~y as described in US patent 5 219,231. The sleeve comprises an annular flange snd the outer WO 95122011 ~ PCT/AU95/00058 2 ~ ~ 2 7 3 2 being means comprises a pair of mutually abuffing rings which together define a recess for receiving the annular flange to allow relative rotation between the race and sleeve and wherein the mutually abuffing surfaces of the rings include an annular flange axially extending from one of said rings and a recess in the other 5 ring, said axially extending flange and cullc:a,uuln~ recess coope,dli"g to retain mutual alignment of the rings.
The col,~l,i.,ldl,le portion is preferably resilient so that the sleeve is movable on the shaft when the locking force of the cu, ,:,l, i..tu, means is removed.
Some examples of practical dll~lly~ ts of the invention will now be described with reference to the a~,cu""ud"ying drawings. However, it is to be ull.l~ uod that the following des~ in no way limits the generality of the invention as described above.

In the drawings:
Figure 1 is a part cross sectional view of a bearing of the invention.
Figure 2 is a partial perspective view of the ~,ulll~,u"~"ts of the bearing of Figure 1.
Figures 3a to 3e are partial p~:,ape~.t;~c views of ~ , constructions of the 25 inner bearing means of Figure 1.
Figure 4 is a further ~Illbu.li,ll~llt of the bearing of the invention.
Figure ~a is a part cross section view of an altemative outer bearing means of the 30 beanng of figure 1.

~ ~ 5~; i -~ 21 8 2~ ~/AU9S/00058 Figure 5b shows a part cross section view of a further example of an altemative outer bearing means for the bearing of the Figure 1.
Figure 5c is an inside p~:,a~e~.ti~c view of an alternative thrust collar of the5 bearing of Figure 1.
Figure 5d is an axial cross section of a further ~"~I,odi",~"L of an outer bearing means and il.'~,.lll~didlt: bearing means of the invention.
10 Figure 5e is an axial cross section of a further t:"l~o~il"~"l of an inner bearing means and i"lc:, " ledidl~ bearing means of the invention.
Figure 6a is a partial p~ Je~,ti~_ views of an inner bearing means of the invention which include means for fixing the bearing to a shaft.
Figure 6b is a cross section of the inner bearing means of Figure 6a which is locked into a shaft.
Figure 6c is partial p~,a~,e~,'iJc view of an inner bearing means.

Figure 6d is a cross section view of the inner bearing means of Figure 6c which is locked into a shaft.
Figure 6e and 6f show a further ~" ,I,odi",t:"l of a lockable inner bearing means in 25 position in which it is movable (6e) and locked (6f) into a shaft.
Figures 7a to 7c show cross sections of " I "./~, inner bearing means for the bearing of the invention.
30 Figures 8a to 89 show the cross section of " " '-l~, shapes of outer circumference portion of the outer bearing means of the bearing of the invention.

Figure 8h shows an outline of the bearing of the invention in the form of a cam.
Figure 1ûa to 10f are pe,~l,e~.lh/c view of housings within which ~ uo~;li"~ ts of the bearing of the invention may be received.

Illustrated in Figures 1 and 2 are co",uu"e";~ of the bearing shown ass~"l~led in Figure 1 and with the cu",!,u"t:"ts separated in Figure 2.
Illustrated is an inner annular bearing means (1) in the forrn of a sleeve for 10 receiving a shaft and having a peripheral bearing surface (2) which forms theannular inner race. The inner bearing means further comprises a pair of shoulders or collars (3) and (4). One of the collars (3) is fixed adjacent the bearing surface and the other collar (4), referred to as a thrust collar may be removed to allow assembly and di:,ass~"ll,ly of the bearing and is received upon15 an annular recessed portion (5) of the inner bearing means (1) on the side of the bearing surface (2) remote from the fixed collar (3).
The outer bearing means (6) is an outer race having an inwardly disposed locating flange (7) which separates two inner radial bearing surfaces (8) on the20 outer bearing means. The flange has parallel sides which when the bearing is as ,~"luled are in face to face ,~ ;Jilsl,iu with the inside sides of collars (3,4).
The inner bearing surface (2) and collars (3 4) of the inner bearing means (1) together with the outer bearing surface (8) and sides of the inwardly disposed flange (7) on the outer bearing means define two annular chambers or recesses.
25 In each of the recesses there is located a set of i" IllC:.lidl~ bearing members (9) including a bearing ring (1û) having bearing surfaces (1112) on its inner circumference (11) and its outer circumference (12) an inner bearing bush (13) having bearing surfaces (1415)on its inner circumference (14) and outer circumference (15) disposed between the bearing ring (10) and the bearing 30 surface (2) of the inner bearing means (1) and an outer bearing bush (16) having bearing surfaces (1718) on its inner circumference (17) and its outer circumference ~18) located between the bearing ring (10) and the bearing surface .

WO 95/22011 . PCT/AIJ95/00058 3 ~ 1 8 Z 7 3 2 (8) of the outer bearing means (6). The inner bearing means (1), outer bearing means (6) and bearing ring (10) are formed of a metal such as aluminium which may be i~ ,u,lldL~d with a plastic coating such as PTFE. The bearing bushes (13,16) are formed of a plastics material such as a polyimide.
The inner bearing surFace (14) of the inner bearing bush is disposed adjust the bearing surface (2) of the inner bearing means (1). The bearing ring (10) inner and outer bearing surfaces (11,12) lie adjacent the outer surface (15) of the inner bush member and the inner bearing surface (17) of the outer bearing bush (16) 10 I~ u~ ,ly. The outer bearing surface (18) of the outer bush (16) lies adjacent and is rotatable with respect to the bearing surface (8) of the outer bearing means (6). Although each of the annular bearing co,,,,uu,,~ (1, 6, 9, 13, 16) is rotatable with respect to any other of the annular bearing cu~,uo'~ ts (1, 6, 9, 13, 16) rotation of the inner bearing means (1) with respect to the outer bearing 15 means(6) has been found to cause the bushes to oscillate between a condition in which they are stationary with respect to the adjacent bearing surface of smaller circumference and rotatable with respect to the bearing surface of greater c~"'~ 'ce and a condition in which the bearing bush is stationary with respect to the adjacent bearing surface of greater circumference and rotatable with respect20 to the adjacent bearing surface of smaller circumference. In particular during operation the inner bearing bush (13) (in each recess) in operation oscillates between a condition in which it is stationary with respect to the inner bearing means (1) and rotatable with respect to the i"' " ' ' bearing ring (10) and rotatable with respect to the inner bearing means (1). The outer bearing bush 25 (16) oscillates between a condition in which it is stationary with respect to the il~t~,llle:didl~ bearing ring (10) and rotatable with respect to the outer bearing means (6) and condition in which it is stationery with respect to the outer bearing means (6) and rotatable wlth respect to the i"' l~ ' bearing ring (10). As a resuU the bushes appear to float between these conditions and the bearing ring 30 also floats, rotating i" Illillt~ ly under the influence of either the inner or outer bearing means.

~, ~,. 21~2~32 ~. 15 Each of the bearing bushes (13 and 16) has a lip (1920) adjacent on edge thereof. The lips (19 20) of the inner and outer bearing bushes (13 16) are disposed each adjacent opposite ends of the i" ",~ bearing ring (10) so that they retain alignment with the illle:""- bearing ring (10) and prevent the - S illLe:llll- bearing ring (10) from directly engaging the first or second bearing members (1,6) by providing an axial bearing surface between ends of the bearing ring (10) and the facing sides of the locating flange (7) and collar (3 or 4). The lip (19,20) in each bearing bush (13,16) has cira,",'~.rt:"Li..l:,r spaced radiatinggrooves (21) on its outer face. The grooves reduce the effects of friction and assist in ~ ;,VdliU~ of heat during operation. Grooves may also be provided on the other end of each bush.
The bearing of the invention may be a55~ blt:d by placing one set of i"~""~ bearing means (9) on the bearing surface (2) of the inner bearing means (1) such that the lip (19) of the inner bush (13) is adjacent the inner side of the fixed collar (3). The outer bearing means may then be located about the bearing surFace (2) of the inner bearing means (1) and the i" ",~ bearing means (9) such that the lip (20) of the outer bush (16) is adjacent the side of the flange (7) facing the collar (3). The second set of i" ~, ~ bearing means (9) is mounted between the bearing surfaces (1) (8) so that lip (20) if the outer bush is adjacent the flange (7) and the thrust collar (4) is fastened onto the recessed end (5) adjacent the bearing surface (2) so that its inner side is adjacent the lip (19) of the outer bush (13).
The i" ", bearing means retain spacing between the inner and outer bearing means (1,6). The outer bearing means extends about the collars (3 4) and ring end flush with the outside of the collar. The il Illedidlt: bearing means retain spacing between the outer bearing means (6) and periphery of the collars (3 4) and the outer bush (16) may extend between the outer bearing means and periphery of the collars (3 4) to provide a seal between inner and outer bearingmeans (1,6).

WO 95/22011 ~ 16 PCT/I~U9S/00058 0 The inner circumference of the flange (7) is also spaced from the bearing surface (2) of the inner bearing means (1) by i, .'~.", bearing means (9).
The outer peripheral surFace of the outer bearing means (6) may be provided with5 means for fixing a bearing. In Figure 1 the outer bearing member comprises a radial hxing flange (23) on it outer circumference (22). Circ~",'~ .~" 'Iy spaced holes (23a) are located about the fixing flange 23 which allow the bearing to befixed to a wheel so it is used as the bearing hub of the wheel.
10 Referring to Figures 3a to 3e the inner bearing means of the invention may include means for attaching the thrust collar to a shaft. The inner bearing means (1) is provided with an annular (5) recess adjacent one end. The thrust collar (4) is annular and its inner circumference is receivable on the recessed portion (5) of the inner bearing means(1) to thereby provide two collars (3 4) spaced at either15 end of the inner bearing surFace (2) between which collars (3,4) the i"~""
bearing means (9) and locating flange (7) of an outer bearing means (6) are received.
As shown in Figure 3a the means for attaching the thrust collar (4) may be by an20 inner (6) annular groove (24) about the recessed portion (5) to allow the end of the recessed portion (5) to be deformed or flared over the outer face of the thrust collar (4). The outer face of the thrust collar may have a chamber (25) adjacentthe inner edge of the outer side wall to facilitate flaring of the end of the recess portion (5).

The inner bearing means (1) further includes an extended axial portion (26) provided with a radial hole for receiving a grub screw to enable the irlner bearing means (1) to be removably fixed onto a shaft.
30 Figure 3b shows an inner bearing means (1) in the fomm of an inner race stud. . The inner bearing means (1) has a solid shaft provided with a collar (3) at one end a peripheral bearing surface (2) adjacent and a recessed portion (5) for 8 2 7 ~C~AU95/~ 58 receiving the thnust collar (4) adjacent the other end of the bearing surFace (2).
The recessed portion is threaded (29) for receiving a nut which may retain the thrust collar (4) adjacent the bearing surface (2~. Alternatively the collar (4) itself may be threaded on its inner circumference to engage and allow it to be fastened5 on the threaded recessed portion (29).
Figure 3(c) and 3(d) shows an inner bearing means in the form of a sleeve for receiving a shaft and the recessed portion (5) and inner circumference of the thrust collar (4) have coope,..:i.ly threaded portions so that the collar (4) may be 10 fastened on the recessed portion (5) adjacent the bearing surface (2). The thnust collar (4) is provided with an additional annular flange (30) on its outer side and the flange has a smaller inner circumference than the threaded portion of the collar so that it lies adjacent one end of the inner bearing means sleeve (32) when the collar is fastened into the recessed portion (5) and may provide a stop15 to deterrnine spacing between the collars (3,4). In figure 3c the additional annular flange (30) is provided with a radial hole (27) for receiving a grub screw to enable the inner bearing means to be fastened onto a shaft. In figure 3d the additional flange (30) is ~l~gd!~dble with a collar (33) which has a hole (27) for receiving a grub screw.
As shown in figure 3e the inner bearing means may include two sleeve portions (34,35) each provided with a collar (3,4) and a portion of the bearing surface (2) and the sleeve portions are t:~gdgdlJI~ such that the bearing surfaces (2) are adjacent and located between spaced apart collars (3,4).
Figure 4 shows a further t~ uu~ of the invention in which the outer bearing means (6) has an internally disposed locating flange (36) which extends across SUL,~dll" ~Iy the entire axial width thereof. The inner bearing means (1) includes a peripheral bearing surface (2) and two collars (3,4) which extend one on each 30 side of the flange (7) of the outer bearing means (6). One of the collars (4) may be removable as shown in Figure 2.

WO 95122011 .~ 8 PCIIAU95100058 The il, lll ' bearing means includes a bearing ring (10), inner bearing bush (13) in the form of a sleeve having an inner bearing surFace adjacent the bearing surface of the inner bearing means (13) and an outer bearing surface adjust the inner bearing surface of the bearing ring (10).
The outer bearing bush member (16) includes axial bearing surfaces on its inner and outer circumference the inner bearing surface being adjacent the bearing ring (10) and the outer bearing surface being adjacent the bearing surface on the inner circumference of the flange of the outer bearing means (6). The outer lO bearing bush also includes two pairs of lips (37,38) one pair (37) disposed on the outer circumference at each end of the outer bearing bush (16) and one pair (38)disposed on the inner circumference at each end. The pair of lips (37) on the outer circumference extend between facing sides of the flange (36) and collars (3,4) and the pair of lips on the inner circumference (38) extending one on either 15 side of the bearing ring (10) to provide a radial being surface between the bearing ring (10) and collars (3,4).
Figures 5a and 5b shows an outer bearing means (6) which includes a internally disposed locating flange (7). The bearing rings (10) is fixed one each side of the 20 flange (7) for rotation with the outer bearing means (6) such that bearing bush means is receivable adjacent each of the inner and outer circumference of the bearing ring. The collars of an inner bearing means (not shown) will be spaced apart from the distal ends of the bearing rings. In figure 5b the outer bearing means inner circumference (8) is provided with annular recessed portions (38) 25 each end for receiving the peripheral end of the collars (3,4) from the innerbearing means (1) such that the collars (3,4) are spaced from the distal ends ofthe bearing rings (10). The bearing means may also include channels or holes (39) for heat transfer or to allow the passage of a lubricant or cooling liquid.
30 Figure 5c shows the inner side of a thrust collar (4) from an inner bearing means (1) the thrust collar may be provided with a helical groove (40) on its inner surface to facilitate the removal of any particles which may become lodged in the bearing .

WO9S/22011 19 ~ t ~?73~TIAU9~00058 through entry of foreign matter or through wear. The helical groove transports particulate matter to the peripheral end of the collar. The collar may also or dlLell ~cly include holes (41) to allow a liquid to enter the bearing. The holesmay be use to facilitate washing of the bearing and will preferably be located in S each of the collars and may be present in any of the bearing c~" ~,uo~e~ ~ts to holes being parallel to or at an angle to the axis.
Figures 5d shows an outer bearing means (ô) having an intemal flange (7) and a bearing ring (10) fused on one side. Bearing bush means includes rings (1316) lO one (13) disposed adjacent the inner circumference of the bearing ring (10) and another (16) adjacent the outer circumference of the bearing ring (10) and the bush rings are joined by a web (43) extending adjacent the distal end of the bearing ring. The web (43) provides an axial bearing surface between the distal end of the bearing ring (7) and collar (not shown). The bush means extends to 15 be flush with the ends of the outer bearing means (6) to provide a seal to inhibit the passage of foreign particles into the bearing. The other side of the flange is provided with a bearing bush (16) having a lip (20) in its inner circumference adjacent the flange (7) in acc~lddll e with the outer bearing bush (16) of Figures 1 and 2 except that the bush extends to the end of the outer bearing means (6) 20 and between in inner circumference of the outer bearing means (6) and the end of the collar (3) to provide a seal.
Figure 5e shows an dllCl"~e",e,l~ in which the inner bearing means (1) includes a radial locating flange (7) on its outer circumference which is provided with a fused 25 bearing ring (10). The ends of the inner bearing means also includes annular recesses (43) to receive the periphery of a collar attached to an outer bearing means. Bush means including inner and outer rings (1316) are joined by a web (42) at a distal end of the bearing ring (10). The other side of the flange is provided with an inner bearing bush (13) with a lip on its outer circumference 30 disposed adjacent the side of the flange (7). Recessed portions (43) are provided at each end of the inner bearing means for receiving collars of outer bearing means which are rotatable about the recessed portions (43).

WO gs/22011 ~--~ ~ S ~ ~ t~ 20 PCTI/.U95/00058 Figures 6a to 6f show inner bearing means (1) for use in the present which is inthe fomm of a sleeve having a bore for receiving a shaft. Figures 6a and 6b showan inner bearing means having a collar (3).
S
A bearing surface (2) is located on one side of the collar (3) with a thrust collar (4) being receivable on a recessed portion (5) on the other side of the bearing surface (2) to receive a flange and i" Ill~didl~: bearing means between the collars for rotation thereabout. The bearing surFace (2) of the sleeve is preferably lO cylindrical.
The sleeve includes an annular Gol,:,~,i.;tdl,l~ portion (44) CGIIluliailly a multiplicity of slots (45) extending through the sleeve at one end. The slots (45) are circ~""~,~" 'l~ spaced to provide a multiplicity of d~:ru""abl~ portions (46). The 15 sleeve lldll~. '.Iy~ tapers toward the slotted the inner bearing means is provided with a co~ , iutur means in the form of a locating nut (47). The inner circumference (48) of the locking nut and the outer circumference of the GOII~Lli- ~dbl~ portion of the sleeve have coacting threaded portions (48 49).
20 To fasten the bearing on a shaft located in the sleeve the locking nut (47) is tightened upon the threaded coll~t~i-ldLI~ portion (44) and thereby urged along the sleeve. Its inner circumference (48) of the nut (47) provides an inward force on the tapered surface of the Gol,~,k;tdl;le portion (44) causing an even inwardly deforming force on the segments (46) between the slots to lock the sleeve into 25 the shaft (48) as shown in 6b. In an ~ uud;~ t the inner surFace of the locking nut (47) l1dll..: lu!y tapers to provide a Gull~lliu'~ force to the cull~lliuld~ portion (44) of the sleeve which may or may not include a tapered portion 30 In the G-lllbudilll~lll shown in figures 6c to 6d the sleeve comprises a flange (7) and a bearing surFaces (2) on either side of the flange (7). The sleeve includes a Gu~l ,ll i-.ldule portion (44) including a multiplicity of slots (45) which extend through WO gS/22011 PCTI~IT^' 21 2 1 ~ 2 7 3 2 the sleeve and provide d~ru,,,,able sections (46) there between which are inwardly tapered and/or have an inwardly tapered outer surface. The sleeve has a threaded portion (49) adjacent the collallk,~dlJI~ portion (44) and a locking nut (47) comprises a coacting threaded portion (48) adjacent the end received on theS sleeve and the coacting threaded portions urge the locating nut (47) into the sleeve. The locking nut (47) includes an annular inner flange (5û) which on tightening of the locking nut (47) on the sleeve urges the COI l ~lliuldlJlt: portion (46) inward to lock onto the shaft (51) as shown in 6d.
10 Figure 6e and 6f show a further dlldlly~lllt:llL in which the locking nut (47) is provided with a thrust collar (4) which may on ass~","; ,9 the bearing provide one of the thrust collar disposed on one side of a inward flange (7) on the outer bearing member (8). On d~ ,.ll' " Iy the bearing one set i" .,"- " bearing means is located on the bearing surface. The outer bearing means (6) is then 15 slid onto the bearing surface (2) followed by the second set of i"~"" "
bearing means (9) and the thrust collar (4) is engaged with the thread of the sleeve (49) and may be tightened as shown in Figure 6f to lock the bearing onto the shaft.
20 Figures 7a and 7b shows a portion of an inner bearing means CullllJIiailly a tapered or fnlalu.,u"i-,al sleeve (52) having a bearing surface (2) and an axialcollar (3) at the large diameter end of the sleeve (2). A th~ust collar (not shown) may be reoeived in the smaller diameter end. The inner circumference of the sleeve may be provided with a spline or senations (53) or other means for 25 engaging a drive shaft or the like.
Figure 7c shows a race portion of an inner bearing means which includes a sleeve (52) with a cylindrical bearing surface (2) and a collar (3) at one end. A
thnust collar (not shown) is receivable at the other end of the sleeve. The bore of 30 the sleeve is provided with spline or serrations (53) for receiving a drive shaft or the like.

WO 95/22011 PcT/A~
22 2t~2732 Figures 8a to 8h show alternative configurations of a outer circumference of theouter bearing means (6). The outer circumference may be cylindrical as shown in 8a convex as shown in 8b particularly of spherical section as shown in 8f. The outer bearing means may include a radial flange or radial protrusions (54) spaced about its outer circumference as shown in 8c. Recesses such as the concave V-shape grooves may be present as shown in 8d and 8e. A peripheral tapered flange (55) adjacent one edge may be useful in a roller for a conveyor belt or the outer bearing means may be a cam as shown in 8h.
10 The outer bearing means may be in the fomm of a housing as shown in figures 9a to 9d such as a pillar block housing (figure 9a) a two flange housing (figure 9b) or four flange housing (figure 9c) having holes (56) for fifing the housing. The outer bearing means may also be in the form of a sprocket or geared when as shown in figures 9c and 9f.
In an alternate ~ bodi~ l ,I the outer bearing means is receivable into a housing of one of the shapes shown in figures 9a to 9f. The outer bearing means may be admitted to the housing by using a split hous~ng and the outer bearing means may have a convex outer circumference spherical section see figure 8f and the 20 housing a concave inner circumference of co~ ,uu~dilly section to allow the outer bearing means to pivot within the housing to align with a shaft or the like. A
hanger type housing is depicted in figure 9d and includes means for engaging an article (57) to be suspended from a conveyance line to be engaged by the outer bearing means.
A particular d~v~..lLdye of the preferred bearing of the invention shown in Figures 1 and 2 is that each of the i, ~t~.",edidLt: bearing c~ ,uu~ ts including the bearing bushes and bearing ring are rotatable with respect to one another which ~iyll'~ ~y reduces wear and minimises build up of heat. Between the inner and 30 outer bearing means there are at least four pairs of radial bearing surfaces and at any time, during operation of the bearing, there may be relative ratation at anyone or more of these pairs of surfaces. Each of the cu~,uù~ ts of the WO 95/22011 . PCI/AU95/00058 '` 23 2 ~ ~2?32 i"~"" " ' bearing means may rotate at a different speed to the inner or outer bearing means and other ~",,uull~ ts. Further, on the build up of fraction and heat between a portion of bearing surfaces they tend to stick together and the presence of a multiplicit,v of pairs of bearings surfaces allows the bearing rings to 5 rotate i, ' ",illt:, 1'l~ or and/or at different speeds to one another, The bearing ring and bushes therefore appear to float, The bearing co",~ù~"l and in particular the bearing ring and inner and outer bushes evenly distribute friction and wear and provide more effective 1i ', " I
10 of heat effectively ~I;.I,i,ldLilly the incidence of ceasure,even at high speed and under great loads.
The presence of load forces in the axis of the bearing generally ~AdC~ . the problems of wear and ceasure in coll~ iulldl plain bearing. In the presence 15 invention the presence of lips on the bushes which extend between the bearingring and collar and the locating flange and bearing ring to provide four pairs of bearing surfaces on each side of the locating flange. The bearing of the invention therefore provides excellent resistance to wear from axial loads.
20 The use of a bearing as the wheel hub of a heavy vehicle provides a severe test of Its p~, ru""d"~ and despite the existence of plain bearings for many years the bearings used in the wheels of vehicles are generally bearings COII~d;llill~ roller balls.
25 A bearing according to Figure 1 and Figure 2 above was constructed using an inner bearing means, outer bearing means and bearing ring constructed of aluminium i" ",, ~yl Idlt:d with PTFE.
The bearing bushes were prepared from polyimide. The bearing was used in the 30 wheel hub of a 11/2 tonnes off road vehicle which was driven at speeds of over 30 miles per hour in swampy terrain frequently being submerged in sea water. The bearing was also used in the wheel hub of a trailer with a total loaded weight of 3 WO 95/22011 ~ " ' PC'I'/AI~ O
24 2 l ~ 2 7 3 2 tonnes. In each case the bearing perfommed ~ y showing litt!e or no sign of wear after extended use.
.
Vehicle wheels of the present invention are su~table for use in vehicles used in5 detecting mines and explosives as they do not generate static electricity. This feature also makes the bearing of the invention desirable for use in scientific instruments in underground mining Op~ s or in other circumstances where it is desirable to guard against static electricity and or the use of ferrous metals or their alloys.

Claims

CLAIMS:

1. A bearing including an inner bearing means (1) having an annular peripheral bearing surface (2), an outer bearing means (6) coaxial with the inner bearing means (1) and having an inner annular bearing surface (8) and at least one set of intermediate bearing means (9) including a bearing ring (10) having an annular inner bearing surface an annular outer bearing surface(11,12) and bearing bush means (13,16) rotatable mounted about the inner bearing means (1) and rotatable with respect to the bearing ring (10) and outer bearing means (6) the bush means (13,16) providing a bearing surface (15) adjacent the inner bearing surface of the bearing ring (11) and providing a bearing surface (17) adjacent the outer bearing surface (12) of the bearing ring (10).

2. A bearing according to claim 1 wherein the bush means includes an inner bearing bush member (13) rotatably mounted about the inner bearing means (1) and rotatable with respect to the bearing ring (10) and having a peripheral bearing surface (15) adjacent the inner bearing surface (11) of the bearing ring (10) and an outer bearing bush (16) rotatably mounted about the bearing ring (10) and having an inner bearing surface (17) adjacent the outer bearing surface (12) of the bearing ring (10).

3. A bearing according to claim 1 wherein one of the inner and outer bearing means includes a locating flange and a radial bearing surface on each side of the flange and the other of said inner and outer bearing means includes a peripheral bearing surface and a pair of collars one collar extending on each side of the flange and the bearing includes two sets of intermediate bearing means disposed between facing sides of the locating flange and collars one set on each side of the flange.

4. A bearing according to claim 1 wherein the bearing ring is rotatable with respect to each of the inner and outer bearing means.

5. A bearing according to claim 2 wherein in operation each of the bearing bushes oscillates between a condition in which it is stationary with respect to the bearing surface of smaller circumference and rotates with respect to the bearing surface of greater circumference and a condition in which it is stationary with respect to the bearing surface of greater circumference and rotatable with respect to the bearing surface of smaller circumference.

6. A bearing according to claim 3 wherein at least one of the bushes in each set is wider than the bearing ring and includes one or more lips which cooperate with the bearing ring to retain the bearing ring spaced apart from the facing sides of the flange and shoulder.

7. A bearing according to claim 6 wherein the bearing bushes in each set together include two or more lips, one lip disposed between the bearing ring and locating flange and another lip disposed between the bearing ring and the facing collars.

8. A bearing according to claim 7 wherein one of the lips radiates from adjacent the side of the inner bearing bush and the outer lip is internally disposed adjacent the side of the outer bearing bush and the lips coact to provide alignment of the ring and to provide axial bearing surfaces between the bearing ring and inner and outer bearing means.

9. A bearing according to claim 8 wherein the bearing bush lips include a plurality of radiating grooves circumferentially spaced on the outer face thereof.

10. A bearing according to claim 1 wherein one of the groups of components selected from a first groups consisting of the bush means and a second group consisting of the inner bearing means the outer bearing means and the bearing ring is formed of a plastics material and the other group of components is formed of metal.

11. A bearing according to claims 10 wherein each of the inner and outer bearing means and the bearing ring is formed of metal and the bush means are formed of a plastics materials.

12. A bearing according to claim 3 wherein the bearing ring of the intermediate bearing means includes of the intermediate bearing means includes a proximal end fused to one of the facing sides of the collar and locating flange and a distal end spaced apart from the other of said facing sides.

13. A bearing according to claim 12 wherein the bush means includes two annular bush rings one ring disposed adjacent the outer circumference of the bearing ring and one adjacent the inner bearing surface of the bearing ring and wherein the bush rings are joined by a web extending adjacent the distal and of the bearing ring.

14. A bearing for a shaft including an inner bearing means including a sleeve for receiving the shaft and having an annular peripheral bearing surface and an outer bearing means rotatable mounted about the sleeve and wherein the sleeve includes an annular constructable portion and constrictor means for providing annular constricting force to the constrictable portion lock the sleeve onto the shaft.

15. A bearing according to claim 14 wherein the annular constrictable portion includes a series of slots circumferentially spaced on the sleeve and generally aligned with the axis on the sleeve and the constrictor means include an annular inner surface adapted to be received on the sleeve and the sleeve and constrictor means comprise engaging means to urge the constrictor means along the sleeve such that the inner circumference of the constrictor means exerts annularly constructing free upon the constrictable portion of the sleeve to lock the sleeve on the shaft.

16. A bearing according to claim 15 wherein the constrictable portion narrowingly tapers at one end of the sleeve and the sleeve and constructor means comprise cooperating threaded portions such that the relative rotation of the constructor means and sleeve urges the constrictor means along the sleeve and against the tapered surface of the constrictable portion to thereby cause constriction of the constrictable portion.

17. A bearing according to claim 14 wherein the inner bearing means has an annular peripheral bearing surface and the outer bearing means is coaxial with the inner bearing means and has an annular bearing surface on its inner circumference and the bearing includes at least one set of intermediate bearing means including a bearing ring having an annular bearing surface on each of its inner and outer circumference and bearing bush means rotatably mounted about the inner ring and outer race the bush means providing a bearing surface adjacent the inner bearing surface of the bearing ring and providing a bearing surface adjacent the outer bearing surface of the bearing ring.