CONNECTION OF A WHEEL HUB BEARING UNIT TO A MOTOR VEHICLE SUSPENSION STANDARD

Abstract: A suspension standard (10) for a motor vehicle has a cylindrical seat (11) for accommodating the outer, non-rotating race (13) of a wheel hub bearing (12). At least one body (16; 16', 16''; 22) distinct from the standard (10) and the outer bearing race (13) has end portions (16a, 16b) extending in a radially outer direction on opposite sides (10a, 10b) of the standard so as to axially lock the bearing with respect to the standard.

Description: Connection of a wheel hub bearing unit to a motor vehicle suspension standard The present invention refers to the mounting of a hub bearing of a motor vehicle wheel to a suspension standard. U.S. Patent No. 5,782,566 discloses a bearing-suspension standard assembly in which the outer race of the bearing has a shoulder on one side and, on the other side, a tubular end portion extending from a seat of the standard in which the bearing is fitted. The part of the tubular end portion projecting beyond the standard is cold deformed by rolling in a radially outer direction against a side surface of the standard, so as to lock the bearing on the suspension standard. In order that the rolling operation is effective, the tubular end portion must not be hardened; the outer race therefore may not be hardened in its entirety but should be induction- hardened only in the zones of the raceways . Some radial interference is provided between the outer bearing race and the standard seat in which the outer race is accommodated, so as to attain a more steady axial and circumferential locking of the outer race with respect to the standard. The present invention has the object of providing a bearing- suspension standard assembly for a motor vehicle wheel, mainly addressing the problem of optimising the axial locking between the suspension standard and the bearing outer race. Another object of the invention is to provide a connection for the bearing which allows to use bearings having an outer race with minimal modifications with respect to the so-called bearings of the first generation, so as to manufacture such components through cost-effective processes. In particular, it is an object of the invention to provide several kinds of connections which allow to use bearings with outer races hardened as a whole, without precluding the possibility of exploiting any cold deforming method, such as rolling, for fixing them to the standard. It is a further object of the present invention to improve the locking of a bearing in a suspension standard made of aluminium. As known, with aluminium standards one can not rely on a locking effect given by the radial interference between the bearing and the standard, as, owing to the different thermal expansion coefficients of aluminium and steel, at the interface between the bearing and the standard the radial interference fails upon reaching normal operation temperatures (about 70°C) . The present invention therefore provides a connection which relies on the axial locking of the bearing with respect to the standard. According to another method of mounting a bearing in a suspension standard made of aluminium, the bearing seat is formed by a steel bushing die-cast in aluminium. The outer race of the bearing is then forcefully fitted in the steel bushing. This technique involves a first complication, inherent in the manufacturing process of the standard. In addition, it is difficult to remove the steel bushing from the aluminium standard by turning for recycling the vehicle components, in accordance with the actual tendency of specifications dealing with recycle . According to a first aspect of the present invention, there is provided a bearing-suspension standard assembly as defined in claim 1 for some embodiments of the invention and as defined in claims 12 , 13 , 14 , and 15 for other embodiments . Further preferred embodiments are defined in the dependent claims . The invention is herein after described with reference to some embodiments thereof, given by way of non-limiting example, reference being made to the accompanying drawings, in which figures 1 to 10 are axial sectional views showing ten alternative embodiments of the wheel-suspension standard assembly according to the invention. For simplicity, in most figures only the radially outer race of the bearing is shown, and not the whole bearing. With reference initially to figure 1, a suspension standard for a wheel of a motor vehicle is indicated 10. As stated in the preamble of the description, the standard may be of aluminium; however, reference to this possible field of use should not be interpreted as in any way limiting the scope of the patent . In the suspension standard 10 there is formed an essentially cylindrical axial seat 11 adapted for receiving a bearing indicated overall 12. The bearing 12 includes a radially outer stationary race 13, a radially inner rotating race 14, in this example a consisting of a pair of half-races fitted side to side, and one or more sets of rolling elements 15 interposed between the outer race 13 and inner race 14. Designated 13a is the outer cylindrical service of the outer race 13, in which there is formed, at an essentially central position or in any case intermediate its and portions, a radial recess 15, preferably in form of a circumferential groove . Prior to the insertion of the bearing in the standard seat 11, a cylindrical tubular sleeve 16 is fitted onto the outer race 13 , sleeve 16 having an undeformed axial length exceed- ing that of the seat 11. Sleeve 16 is then permanently deformed at the bearing groove 15, so as to yield a deformed portion 17 projecting within the groove 15 and locking the sleeve 16 axially with respect to the outer race 13. Once such locking action has been carried out, the unit comprised of the bearing 12 with the sleeve 16 is inserted in the standard seat 11. The axial end portions 16a and 16b of the sleeve, which are initially undeformed as shown in phantom, are bent by cold forming, preferably by rolling, in a radially outer direction against the respective inner 10a and outer 10b side surfaces of the standard 10. The bearing 12 is so securely fixed to the suspension standard. According to a possible variant of the embodiment shown in figure 1, the sleeve 16 may be preformed such that only one of its end portions, 16a or 16b, is already radially folded, or flanged, so as to require a rolling operation to be carried out only on the other end portion (16b or 16a) to lock the bearing axially on the standard. While it is preferable that a slight radial interference is provided between sleeve 16 and the cylindrical outer service 13a of the outer race 13 so as to lock the sleeve 16 with respect to the outer race 13 while the protruding portion 17 is being cold-headed into the groove 15, it is advantageous to provide a slight radial interference between the sleeve 16 and cylindrical seat 11 of the standard to keep the sleeve- bearing unit steady with respect to the standard while rolling the end portion (16a or 16b) that is deformed first. In any case, this interference does not serve to secure the bearing in operation but simply to facilitate a correct axial positioning of the bearing-sleeve unit during the rolling step. Referring now to figure 2, there is shown an alternative embodiment in which the outer race 13 of the bearing is fixed to the tubular sleeve 16 by welding, in this example at both the axial end portions of the outer race 13 , as indicated by reference numerals 18. Once the outer race 13 and sleeve 16 are connected, the so formed unit is inserted in the standard seat 11 and locked to the standard 10 by cold forming of the axial end portions 16a and 16b of the sleeve 16. Also for the embodiment shown in figure 2, there may be a variant in which the sleeve 16 is preformed so as to exhibit one of its axial end portions already radially folded (or flanged) before it is fitted to the standard. To practice the example of figure 2 it is necessary that the outer race 13 is made of weldable steel, for example SAE 1070 or SAE 1055, and that the tubular sleeve 16 has a low carbon content . With reference to figure 3 there is shown another alternative embodiment of the present invention, according to which the outer race 13 of the bearing is forcefully fitted with radial interference in the tubular sleeve 16. The axial mutual position between these two elements is determined by a pair of elastic annular members 19, for example seeger rings. The elastic annular members 19 are partially received in respective grooves 20 obtained in the inner cylindrical surface 16c of the sleeve 16 and axially spaced so that both the seeger rings 19 abut against the opposite end faces of the outer race 13. In this embodiment, high radial interference must to be provided between the outer race 13 and the sleeve 16 , as such a forced coupling has the task of preventing relative axial displacement between the elements 16 and 13. The seeger rings δ 19, owing to their elastic construction, are not capable of guaranteeing an effective contrasting action. As to the fixing of the bearing-sleeve unit to the standard by means of rolling, the same remarks apply as discussed above with reference to the previous drawings . Referring now to figure 4 , according to a further embodiment of the present invention, the sleeve 16 is formed by joining a pair of tubular half-elements 16' and 16'' each of which as a respective axial end portion 16a, 16b preformed and flanged in a radially outer direction. The half-elements 16', 16'' are axially dimensioned so that, once they are inserted one from the outboard side and the other from the inboard side of the cylindrical seat 11 of the standard, they are welded together at 23 so as to axially clamp the standard by means of the preformed ends 16a, 16b. The outer baring race 13 is then forcefully inserted in the sleeve so assembled on the standard. The axial position of the bearing with respect to the sleeve 16 is determined by a pair of annular elastic members, in this example seeger rings, indicated 19 and partially received in circumferential grooves 20 previously formed in the inner cylindrical surfaces of the half-elements 16' and 16'', in a manner similar as described with reference to the embodiment of figure 3. Also in this case the radial interference between the outer bearing race and the sleeve 16', 16'' must be high so as to provide a forced coupling preventing the outer race 13 from sliding axially with respect to the sleeve 16 and the standard 10. A further embodiment is shown in figure 5, where recesses 21 are formed in the outer bearing race 13 and in particular in the radially and axially outer zones; the recesses 21 consti- tute anchoring seats for a pair of annular edge bodies 22 made of sintered material, which serve to provide axial locking means with portions (still indicated 16a and 16b) extending beyond the opposite side surfaces of the standard. The edge annular bodies 22, initially straight as indicated in phantom at 22 ' , are applied to an outer race 13 having recesses 21; the bearing is then inserted in the standard seat 11. The edge bodies 22 are then bent by rolling, folding them in a radially outer direction, so as to clamp the opposite side faces of the standard as shown in the drawing in full line. According to a possible variant of the embodiment figure 5, one of the two edge bodies 22 can be applied to the outer bearing race in its final shape with its flanged end portion already protruding in a radially outer direction; in this way, after slipping the bearing in the standard, only the other annular edge body has to be cold deformed to lock the bearing axially with respect to the standard. In the embodiment shown in figure 6, the standard 10 forms a radial shoulder 40 protruding radially and inwardly beyond a side of the seat 11. At the opposite side, in the standard there is formed a recess in form of annular groove 41 which opens towards the centre of the seat with a pair of diverging conical walls 42, 43. A separate annular element 45 is positioned adjacent to the side of the outer race 13 opposite to the shoulder 40; the element 45 is cold deformed, preferably by rolling, so as to partially penetrate the groove 41 and axially lock the outer bearing race 13 in the standard seat 11. At the entrance of the groove there is formed an axially protruding annular relief 44 which serves as a retaining element to positively and firmly lock the annular element 45 after it has been deformed. In the embodiment of figure 7, two recesses 30, 31, preferably in form of circumferential grooves, are obtained in the radially outer surface 13a near the edges thereof for receiving respective annular locking elements 32, 33. The annular elements 32, 33, preferably in form of open rings, are shaped so as to each have: a respective portion 32a, 33a, protruding in an radially inner direction to engage a respective groove 30, 31; a respective portion 32b, 33b protruding in a radially outer direction for abutting against the respective side surfaces 10a and 10b of the standard; and a respective essentially cylindrical portion 32c, 33c joining the said portions 32a and 32b, and portions 33a and 33b. The cylindrical portions 32c and 33c are fitted between the cylindrical standard seat 11 and the edges 13d and 13e of the outer race 13. Both edges 13d and 13e have an outer diameter slightly smaller, with respect to the central part of the race 13 , for accommodating the portions 32c and 33c. One of the edge portions of the race 13, in this example the axially inner edge portion 13e has a diameter smaller than the other edge portion 13d so as to define with the seat 11 a wider gap 34 for facilitating the insertion of the annular element 33. The mounting of the bearing on the standard takes place as follows. First the annular locking element 32 is fitted to the outer race 13, with the portion 32a engaging in the groove 30; then, the bearing is inserted in the seat 11, with the portion 32b abutting against the side surface 10a of the standard. The annular element 33 is then elastically widened, against its elastic force, and it is inserted in the gap 34 until the portion 33a snaps into the groove 31 and the portion 33b abuts against the side surface 10b of the standard. The outer race 13 is so locked on the standard. In figure 8 there is schematically illustrated a still different embodiment, in which the cylindrical standard seat 11 is delimited at its axially inner side by a radial protuberance 35 which constitutes an abutment means for the outer bearing race 13. In the axially outer zone of the cylindrical seat 11 there is formed a recess 36 adapted for partially receiving an abutment means in form of an annular elastic element 37, for example a seeger ring, which acts as an axial abutting and locking means at the outboard side. Between the outer race 13 and one of the two above said abutment means, in this example between the outer race 13 and the annular element 37, there is axially interposed a further annular element 38 of a material having a thermal expansion coefficient greater than that of steel. The annular element 38 is dimensioned so as to be inserted in a completely axially compressed condition, or in any case in such manner that no axial play is left between outer race 13 and the abutments 35 and 37. Upon reaching the normal operation temperature, the annular element 38 tends to expand axially and, in doing so, preloads axially the outer race 13 and keeps it firmly locked in the standard. As will be apparent, in all the embodiments described so far, the outer race 13 may be made from an annular element for bearings of the so-called "first generation", carrying out a minimal additional machining operation to form the groove 15 in the example of figure 1 and the edge recesses 21 in the example of figure 5. Above all, the outer bearing race may advantageously be hardened as a whole, without having to carry out a more expensive induction hardening in order to harden only the zone of the raceways . With reference to figure 9, the standard seat 11 and the radially outer surface 13a of the outer race 13 are both conical and congruent, being tapered towards the outboard side of the vehicle (on the left in the drawing) , or, according to an alternative embodiment (not shown), towards the inboard side. In the embodiment of figure 9, the outer race 13 in unde- formed condition (as shown in phantom) is inserted in the seat 11 from the inboard side of the standard, until it abuts in the axial position predetermined by the conical coupling of the surfaces 13a and 11. Once this position has been reached, the axially outer end portion 13d of the race 13 is cold deformed in a radially outer direction, for example by rolling, against the side surface 10b of the standard, thereby locking the race 13 with respect to the standard. Finally, in the variant of figure 10, the standard 10 is shaped as described with reference to figure 6, with a shoulder 40 protruding radially and inwardly from one side of the seat 11 and, on the opposite side, with a recess in form of circumferential groove 41 with an axially protruding annular relief 44. The outer race 13 of the bearing has a tubular axial end portion 13d which is cold deformed, for example by rolling, so as to partially penetrate in the groove 41 and axially lock the bearing in the standard seat 11. By virtue of the relief 44, the axial cross section of the groove 41 has an angular development greater than 180 degrees so as to positively lock the deformed end portion 13d of the bearing race 13.

Claims: CLAIMS 1. A bearing and suspension standard assembly for a motor vehicle wheel, comprising: a suspension standard (10) , in particular made of aluminium, a bearing (12) with a non-rotating outer race (13) fixedly mounted in an essentially cylindrical seat (11) of the standard (10) , and locking means co-operating with the outer bearing race (13) and opposite side surfaces (10a, 10b) of the standard (10) so as to axially lock the bearing with respect to the standard, characterised in that said locking means are formed by end portions (16a, 16b) extending in a radially outer direction from at least one body (16; 16', 16''; 22) distinct from the standard (10) and the outer bearing race (13) and fixedly secured to the outer race . 2. The assembly of claim 1, wherein said locking means (16a, 16b) are opposite end portions of and axial sleeve (16) radially interposed between the bearing outer race (13) and the standard seat (11) . 3. The assembly of claim 1, wherein at least one of said end portions (16a or 16b) is bent against a side surface (10a or 10b) of the standard (10) by cold forming after the insertion of said at least one body (16; 16', 16''; 22) in said seat (11) . 4. The assembly of claim 3, wherein both said end portions (16a, 16b) are bent against respective side surfaces (10a, 10b) of the standard (10) by cold forming after insertion of said at least one body (16; 16', 16''; 22) in said seat (11) . 5. The assembly of claim 1, wherein one of said end portions (16a or 16b) is preformed in said radially outward direction prior to the insertion of said at least one body in said seat (11) . 6. The assembly of claim 2, wherein the outer race (13) has at least one radial recess (15) in its outer cylindrical surface (13a) and wherein said sleeve (16) is joined to the outer race (13) by deforming a portion (17) of the sleeve in said recess (15) . 7. The assembly of claim 2, wherein the outer race (13) is made of weldable steel and the sleeve (16) is joined to the outer race (13) by welding (18) . 8. The assembly of claim 7, wherein the sleeve (16) is forcefully inserted with radial interference in the seat (11) of the outer race (13) , and wherein there are provided two annular elements (19) disposed adjacent to the opposite axial ends of the outer race (13) and partially received in respective radial recesses (20) obtained in an inner cylindrical surface (16c) of the sleeve (16) . 9. The assembly of claim 2, in which the sleeve (16) is formed by joining two sleeve half-elements (16', 16'') each preformed with a first end portion (16a, 16b) flanged in a radially outer direction, the two half-elements being joined by welding at their second end portions . 10. The assembly of claim 9, wherein said sleeve half- elements (16', 16'') are forcefully inserted with radial interference in the standard seat (11) and wherein there are provided two annular elements (19) disposed adjacent to the opposite axial end portions of the outer race (13) and partially in respective radial recesses (20) obtained in inner cylindrical surfaces (16c) of the two sleeve half-elements (16' , 16' ' ) . 11. The assembly of claim 1, wherein said locking means are provided by two annular bodies (22) of metallic sintered material, anchored in corresponding seats (21) formed near the end portions of the outer race (13) . 12. A bearing and suspension standard assembly for a motor vehicle wheel, comprising: a suspension standard (10) , in particular made of aluminium, a bearing (12) with a non-rotating outer race (13) fixedly mounted in an essentially cylindrical seat (11) of the standard (10) , and locking means (35, 37) axially spaced from one another and defining axially fixed positions with respect to the standard, characterised in that said locking means further include at least one annular member (38) axially interposed between one of said axially spaced locking means (35, 37) and the outer race (13) , said at least one annular member (38) being made of a material with a thermal extension coefficient greater than that of steel, whereby upon reaching operation temperature the annular member (38) axially preloads the outer race (13) between said axially spaced locking means (35, 37). 13. A bearing and suspension standard assembly for a motor vehicle wheel, comprising: a suspension standard (10) , in particular made of aluminium, a bearing (12) with a non-rotating outer race (13) fixedly mounted in an essentially cylindrical seat (11) of the standard (10) , and locking means (40, 41) axially spaced from one another and defining axially fixed positions on the standard, characterised in that said locking means further include at least one radial recess (41) formed near at least one of the axial end portions of the seat (11) , said radial recess (41) being adapted for receiving partially an annular member (45) separate from the bearing and the standard and adapted for being cold deformed in said recess (41) so as to interpose between the outer race (13) and the standard (10) and so define an axial stop for the outer race. 14. A bearing and suspension standard assembly for a motor vehicle wheel, comprising: a suspension standard (10) , in particular made of aluminium, a bearing (12) with a non-rotating outer race (13) fixedly mounted in an essentially cylindrical seat (11) of the standard (10) , and locking means co-operating with the bearing outer race (13) and opposite side surfaces (10a, 10b) of the standard (10) for axially locking the bearing with respect to the standard, characterised in that said locking means are formed by end portions (32b, 33b) radially outwardly extending from a pair of annular members (32, 33) arranged for engaging respective recesses (30, 31) formed in proximity of axially opposite edge portions (13d, 13e) of the outer race (13) . 15. An assembly according to any one of the preceding claims, wherein the outer race (13) is hardened as a whole. 16. A bearing and suspension standard assembly for a motor vehicle wheel, comprising: a suspension standard (10) , in particular made of aluminium, a bearing (12) with a non-rotating outer race (13) fix- edly received in a seat (11) of the standard (10) , wherein an axial end portion (13d) of the outer race (13) is cold deformed in a radially outer direction against a side surface (10b) of the standard for axially locking the outer race (13) on one first side, characterised in that said outer race (13) has an essentially conical radially outer surface (13a) and in that said seat (11) has an essentially conical shape matching that of the essentially conical surface (13a) so as to axially lock the outer race (13) on the side opposite said first side. 17. A bearing and suspension standard assembly for a motor vehicle wheel, comprising: a suspension standard (10) , in particular made of aluminium, a bearing (12) with a non-rotating outer race (13) fixedly mounted in an essentially cylindrical seat (11) of the standard (10) , and locking means (40, 41) axially spaced from one another and defining axially fixed positions on the standard, characterised in that said locking means include at least one radial recess (41) formed in proximity of at least one of the axial end portions of the seat (11) , said radial recess (41) being adapted for receiving partially receiving an axial end portion (13d) of the outer race (13) cold deformed in said recess (41) for axially locking the outer race (13) on the standard (10) . 18. The assembly of claim 13 or claim 17, characterised in that it further comprises a relief (44) axially protruding in the recess (41) .

Inventors: BERTETTI PAOLO, IARRERA FABRIZIO, PICCA MAURO, RUETTER ANDREAS, BERTETTI, PAOLO, IARRERA, FABRIZIO, PICCA, MAURO, RUETTER, ANDREAS
Applicants: BERTETTI PAOLO, IARRERA FABRIZIO, PICCA MAURO, RUETTER ANDREAS, SKF IND SPA, BERTETTI, PAOLO, IARRERA, FABRIZIO, PICCA, MAURO, RUETTER, ANDREAS, SKF INDUSTRIE S.P.A.
Application year: 2001
Main classification: B60B27
IPC codes: B60B27, B60B35, F16C19, F16C35