GB2204646A

GB2204646A - An improved bearing for supporting a rotating member and a process for its manufacture

Info

Publication number: GB2204646A
Application number: GB08810273A
Authority: GB
Inventors: Franco Colanzi
Original assignee: RIV SKF Officine di Villar Perosa SpA; RIV Officine di Villar Perosa SpA
Current assignee: SKF Industrie SpA
Priority date: 1987-05-08
Filing date: 1988-04-29
Publication date: 1988-11-16
Anticipated expiration: 2008-04-29
Also published as: ES2008462A6; FR2614955A1; IT1208884B; GB2204646B; GB8810273D0; FR2614955B1; DE3814920A1; IT8767395A0

Description

10;1 f l- a 1.& 2204646 1 AN IMPROVED BEARING FOP SUPPOPTING A ROTATING

MEMBER AND A PROCESS FOR ITS MANUFACTURE The present invention relates to an improved bearing, in particular for vehicle wheels, capable of supporting a rotating member and simultaneously allowing the detection of the angular speed of this rotating member by means of an electromagnetic sensor, for example forming part of a control circuit such as an ABS type anti-lock wheel braking circuit. The present invention further relates to a simple and economic process fc-.- producing the said bearing.

It is known that currently, especially on sports motor vehicles or the socalled "grand touring" vehicles- there are installed special control circuits of the type known f preventing locking of the as ABS having the purpose o. wheels of the vehicle during braking; these circuits comprise, as is known, an hydraulic operative part acting by means of valves on the brake circuits, and an electronic control part able to cause the operative part to ntervene when a differential variation in the speed 0.1r rotation of the wheels of each axle of the vehicle hreshold'is detected; these greater than a predetermined variations in speed are detected by a suitable known circuit making use of electromagnetic sensors, at least 1 2 one for each wheel of the vehicle, which emit a pulse signal proportional to the speed of rctation of the wheel controlled by it; this pulse signal is obtained in the majority of cases by mounting, usually on the wheel support bearing, a toothed element known in the art as a Monic wheel" or Mpulse ring"; this element essentially comprises a flange of ferromagnetic material fixed for rotation with the wheel and provided with a toothed ring in correspondence with which the sensor is mounted; io during rotation of the wheel, therefore, alternate passage past the sensor of the solid parts constituted by the teeth and the mcids constituted by the space between the teeth causes a periodic variation in the air gap between the flange and the sensor and, therefore, a is periodic variaticn in the magnGtic field with a consequent generation by the sensor of a periodic oscillating sIgnal the frequency of which is proportional to the speed of rotation of the wheel.

A disadvantage of the detection system described above lies in the large bulk of the sonic wheel and in its cost, which is also high, due to the fact that this wheel, because of the precision with which it must be made, has to be formed entirely by material removal operations; the necessity of mounting a supplementary member such as a tonic wheel noreover makes the assembly 1 1 3 and maintenance operations of the whole of the mechanical assembly of the vehicle suspension more complex and, finally, increases the weight of the suspension itself and therefore the mass displaced by bumps in the ground during movement of the vehicle, with consequent reduction in the response of the suspension to stresses, and therefore a reduction, even if only slight, of the roadholding which, on the other hand, it is desired to increase.

The object of the invention is that of providing a support bearing for a rotating member, and in particular for a vehicle wheel, shaped in such a way as to per.mt the elimination of the sonic wheel and, consequently, operable to incorporate its function in such a way as be simultaneously capable of supporting the wheel, connecting it to the vehicle suspension, and to cooperate with a sensor to permit detection of the angular velocity of the wheel itself. A further object of the inventior then is that of providing a simple, low cost process for the production of a bearing of this type.

to The said objects are achieved by the invention in that it relates to-a support bearing for a rotting member, in particular for the wheel of a vehicle, characterised b:y the fact. that a ring of the said bearing, which can be f k, , n 4 directly connected for rotation with the said rotating member, is externally provided with an annular groove at least partially filled with a solid substance; the said solid substance having been shaped within the interior of the said annular grcove substantially"in the form of a toothed ring in such a way as to define, parallel to a botton: wall. of the said annular groove and on the opposite side thereof, within the said annular groove, a troughs having a regular plurality of peaks and t successlOn.

The invention further relates to a process for producing a support bearing fci- a rotating mer,-,ber operable to permit the detection of the angular velocity of the said member by means of a sensor, for example an electrcmagnet-Jc sensor, characteriseldl by the fact that it comprises the following stages: f a - forming an annular groove on the ou4N..side c. ring of tIne said bearing which cafl. be connected LEC,-i rotation with the said rotating member; - casting into the said annular grcove a fluid substance in a pasty state; - plastically working the said fluid substance within the said annular groove, in such a way as tc form in the fluid substance a regular succession of peaks and troughs; and 1 1 j - leaving the said fluid substance to harden within the said groove after having worked it, in such a way as to form therewith, within the said groove, a substantially toothed ring.

For a better understanding of the invention there is now given a nonlimitative description of an embodiment thereof with reference to the attached drawing, in which:

tive a bearing Figure 1 illustrates in perspect of formed accord-ng to the princ he invention and, in a schemat-ic manner, -Jts Itwc production stageE; and Figure 2 is a partial sectoned vJew L.1 L - - of Ithe bear4n f - 9 of Figure With re-'ei-ence to Figures 1 arid 2, a support for a wheell 22 of a vehicle not. illustrated for simplicity or any other type of rotating member, is generally indicated with the reference numeral 1; the bearIng illustrated by way of non-limitative example is of the so-called "secz)nd generation" type and therefore comprises an outer ring 3 provided with a radially outer flange 4 facing towards the wheel 2 and on which the wheel. 2 itself is fixedly mounted in a known manner, and an inner ring 5, preferably formed by twc half ring-s 6 and 7, which can be fixedly angularly mounted in a known d,k 6 manner not illustrated for simplicity with c constant velocity joint if the wheel 2 is a driven wheel, or with a simple support pin if the wheel 2 is not a driven wheel; in a known way, between the rings 3 and 5 there are interposed respective sealing members 9 and 10 and rolling bodies, which may be constituted for example by balls 8; the flange 4 is provided with through holes 11 for direct fixing to the wheel 2 such that the outer ring 3 also performs the function of a hub; it is evident, - limitative and however, t'llat this =figuration is not that what is described hereinbelow can therefcre be. applied to any bearing of any type whatsoever. In particular, according tc the invention, the bearing 1 haT - ed so as to be turnable with the a ring which can be mount member tc. be supported, in this case the outer ring 3, provided externally with an annular grocve 12 which is tance 13 filled, at least partially, with a solid s-ibst fixed securely in the groove 12. and shaped in such a way as substan't--ial)y to form. a toothed ring 14 (Figure 1); in particular, the solid substance 13 totally fills the groove 12 in places, in such a way as to define within this, parallel. to a bottom wall 15 of the groove 12 and on the opposite side from the bottom wall 15 itself, a plurality of peaks and troughs disposed- in a regular -ucession, respectively formed by respective teeth 16 and by respective spaces 18 disposed alternatively along 1 the whole extent of the groove 12.

In a preferred'embodiment the solid substance 13 of which the toothed ring 14 housed fixedly in the groove 12 is formed is constituted by a solidified paste comprising a matrix formed by a polymerised synthetic plastics resin and a homogeneous filler dispersed within the matrix and constituted by a ferromagnetic substance in powder or granules for example constituted by iron filings; the annular groove 12 is preferably formed frontally at one end 20 of-the outer ring 30 opposite that on which the wheel 2 is mounted And provided with the flange 4; if the dimensions of this end 20 are not sufficient to house a quantity of solid substance 13 such as to form a toothed ring 14 of sufficient dimensions to cooperate with a sensor 21, in the illustrated example an electromagnetic sensor, of any known type, to ac. hieve detection of the " and, with it, the wheel speed of rotation of the ring.0 2, the end 20, in a possible variant of the bearing the subject of the invention can be provided or. its exterior with a radially projecting flange 22 similar to the flange 4 but smaller, illva-strated in brokeri outline in f Figure 2, in-which is formed, frontally, a groove 12 o adequate dimensions. -.In use the bearizv 1 is mounted in a known way, not illustrated for simplicity, tolthe suspension of a vehicle and the wheel 2 is mounted on it; W.

1 opposite the toothed ring 14 is placed the sensor 21 whicht in the illustrated example, is constituted substantially by a simple electromagnet connected in a known way not illustrated for simplicity to an oscillating electronic detector circuit of known, type and therefore also not illustrated for simplicity; during rotation of the wheel 2 the teeth 16 and interdental spaces 18 pass successively in front of the sensor 21 and, being made of a ferromagnetic material, thanks to the presence of the iron filing filler cr other substance having similar characteristics, causes a periodic variation in the magnetic flux and, therefore, the generation by the sensor 211 of a periodic pulse signal having a frequency proportional to the number c.' teeth and spaces which pass in unit time in front'of it, or rather, to the speed of rotation of the wheel 2; this J signal, can then be utilized, for example, in an ABS system of known type, not illustrated for simplicity, by comparing it with analogue signals coming from similar sensors cooperating with other bearings identical to the bearing 1 and supporting the other wheels of the vehicle to determine the onset of ancinalous diffenential variations in the speed of these and consequently to control, in a.known way, and which is therefore not descr ibed for simplicity, icii example appropriate valves in the vehicle braking circuit.

f 1 9 r To produce the bearing 1 a known process is followed save for the formation, of the annular groove 12 at the end 20, for example by removal of material or, more simply, directly in the forming stage producing the outer ring 3 which is known, and not illustrated for simplicity; subsequently, a fluid paste 13 having a high viscosity is prepared, having a substantially pseudoplastic beha.. 4-cur or similar, which is cast or mouldfied, preferably by injection, into the groove!.'c- fQr example bl. means z:l a ); the pasta 13 can '.-je made nozzle 3C (Figure 1, -he invent. i f orr -Mn a fluid t c. 11 on by un;.ly d-Spersing wit - 1 y constituted by a resin or mixture of partial. pwl--.mer-4sed synthe4-',-plastics res-ins, a filler 1-5 constituted by a.$,:errcmagnel-ic substance such as mac:net.i't.e powder, iron filings cr the like; this mixture: constitutes the paste 131 which, by the action of heat and.lor the addition off polymerising substances such as activators and/or other monomers or polymers able tc -)o react, chemically with the, causes hardening once deposited in the groc,.ie 12 thereby becoming solid, for e-..-.ariple by the effec-t of a three cross-li.nking; before this solidification takes plaze cl is completed, the intreduced intc, the grcove 12 through the nozzle 3G -i-- worked, accordina tc.

f forr,.,-5ng the invention, in a plastic manner by r-.ear-. cf a 1 tool constituted by a toothed pinion 31 which is rotated about its axis of symmetry and simultaneously displaced at constant speed along the groove 12, facing this (Figure 1)'-in such a way that its teeth 331 p-.e-- !: into the plastic mass constituted by the paste 13 forming in it the spaces 18 and, simultapeously, forming a corresponding tooth 16 between each pair of spaces 18 which are formed; the excess paste 13 is expelled from the groove 12 and collected, for example by meanE: of a JC hopper not illustrated. Once the whole of the paste 13 deposited-in the groove 12 has been worked, the-paste 13 is left to solidify in such a way as to obtain finally, by its hardenidg, the toothed ring 14. This, because of the manner with which it is obtained, and because of the superficial chemical and physical bonds which can form between the resin upon polymerisation and the material, usually steel, of the outer ring 3, is substantially anchored within the ring 3 itself; this anchorage can be improved, if desired, by forming, p the groove 12, asperities, knurling, teeth or similar shoulders which subsequently become embedded into the paste 13 upcn moulding ther'eof so that 4-hese r. emain incorporated in the toothed_ring..14.-, The preparation of the paste 13 does not propose problems and any technicalsexpert in polymers can produce h undreds of different formulations, all equally effective for the purpose of the present k E, invention, so tll J. E.

hat for s,..ml.,licity we will not enter he: into the n,.ez.Jt of the specific ecmposit4on thereof; however, it is evident that any knDwn epoxy resin is particularly adapted for the purpose as also are any -emperature thermosetting resirxs of the two other ambient 4. component Ilype available on the market.

From what has been described the advantages connected with the bearing according to the nvention will be apparent; in substance, it incorporates the sonic wheel, the of the outer ring so that a ccns'mde:-atie reduction in the dimensionE and a notable r 4 1 a c- 41 cf assembly respect to assembi.es ut-411.1sed untill now constituted by the bearing., and --cr.ic i,,,heel- mounted so as to project from it; moreover, a considerable reduction in weight is obta-ned in that one metal cc:T,Pc.nent (the sonic wheel) iS eliminated, and a groove LE formed which reduces Ithe weight of the outer ring 3, this reduction not being compensated by the ^0 weight c.' the paste 13 which, being constituted predominantly of plastics material has a low density with respect tc the metal. Finally, the bearing 1 can be obtained in g simple, rapid and economic- manner thanks to he arrangements for production of the toc5thed ring by Plastic wcrking of a paste which -45 subsequently hardened. This arrangement further permits a 1 r manufacturing precision also to be obtained it is clear that, the invention can also be .,nally, to cooperate with sensors applied to bearings intended t other than electro-magnetic sensors, for sensors, provided that they are adapted by the passage of a succession cf peaks these defined by the toothed ring 14; in this ca--.e the paste 13 can also be prepared without a filler, ezpecially a ferromagnetic- one, and could merelly be ' wax.

constituted by a simple heat sof'-ene4 J example optical to be activated and voids such as 1 l 1 13. -

Claims

1 A bearing for supporting a rotating member, in particular for a-wheel of a vehicle, characterised by the fact that,a ring of the said bearing, which can be directly connect.ed for rotation with the said rotating member is provided externally with an annular groove at least partially filled with a solid substance...

the said solid substance having been shaped within the said annular groove substantially in the form of a tootllgd ring in such a way as to define, parallel to a b:)ttom wall of the said annular groove and on the opposite side thereof, within the said annulax groove., a plurality of peaks and is troughs having a regular succession.

j 2. A beari A ng according to Claim 1, characterised by the fact that the said solid substance disposed within the said annular groove is constituted by a solidified paste comprising a matrix of polymerised synthetic plastics resin in which is uniformly dispersed a filler of ferromagnetic subt; ta:nce, for example iron fi I ings.

3. A 1)earing'_accorcling to Claim 1 or Claim 2, characterised by the fact that the said annular groove !I- - -. r.

14 -. ---is formed frontally at one end of an outer ring of the bearing opposite that on which the said rotating member can be mounted.

is 4. A bearing according to Claim 2, characterised by the fact that the said end of the said outer ring of the bearing provided with the said annular groove is also provided, with an outer radial flange, the said groove being formed frontally in the said flange.

0.

A process for obtaining a support bearing for a -ion of t&'-.e rotating member able to permit the detect angular velocity of the said member by means of a sensor for example an electromagnetic sensor, characterised by the fact that it comprises the following stages; - forming an external annular groove on a ring of the said bearing which can be connected for rotaltion with the said rotating member.

- moulding a fluid.substance -&.te in a pasty st, into the said annular groove; plastically working the said fluid substance within the sal, d-lannular groove in such,,a way as to form in the fluid substance a regular succession of peaks and troughs; and 1 0 M.

- leaving the said fluid substance to harden within the said groove after having worked it, in such a way as to form therewith a substantially toothed ring within the said grocve.

A - 22 ZE 6. 7, process acccrding to Claim 5, characterised by the fact that the said fluid substance in the pas' 1 e state comprises a matrix of a synthetic polymeric resin' and a filler constituted by a ferromagnetic substance which -IE uni.'crmly d-ispe-sed throughout the sa-Ld matri.....

7. A process acczrding to Claim 5 or Claim 6, characterised by the fact that the said stage of ,.las±-:ca.ll-y working the said fluid substance moulded d annular groove withl.n the sa- is performed by means of a forming tocl shaped as a toothed pinion which is cauEed to rotate abcut its own. axis of symmetry and simultaneously displaced alc-,-.9 the said groove frontally thereto.

16 - 8. A bearing for supporting a rotating member, the beari ng bei ng substanti a] ly as hereinbefore described with reference to, and as illustrated in, the accompanying drawings.

process for obtaining a support bearing for a rotating member able to permit the detection of the angular velocity of the member by means of a sensor, the process being substantially as hereinbefore described with reference to the accompanying drawings.

i Published 1988 at The Patent Office State House 66,71 Rid', Holborn Lond UM I - - I I on er copies may be obtained from The Patent Office, Sales Branch, St Mary Cray, Orpington, Kent BR5 3RD. Printed by Multiplex techniques ltd, St Mary Cray, Kent. Con- 1/87.