JP4499075B2 - Drive wheel bearing device - Google Patents

Description

  The present invention relates to a wheel bearing device that rotatably supports a driving wheel of an automobile with respect to a vehicle body, and more specifically, a hub wheel, an outer joint member of a constant velocity universal joint, and a double row bearing are unitized. The present invention relates to a drive wheel bearing device in which at least one of double row inner races is formed on an outer joint member.

  Driving wheels of automobiles such as a rear wheel of an FR vehicle, a front wheel of an FF vehicle, and all wheels of a 4WD vehicle are supported by a suspension device by a driving wheel bearing device. As a conventional drive wheel bearing device, for example, there is one shown in JP-A-11-62951.

As shown in FIG. 12, the bearing device has a structure in which the hub wheel 10, the bearing 20, and the constant velocity universal joint 30 are unitized, and one of the double-row inner races is formed on the hub wheel 10. The other 42 is formed on the outer joint member 40 of the constant velocity universal joint 30. The hub wheel 10 and the outer joint member 40 engage a female spline 53 formed on the inner peripheral surface of the hub wheel 10 and a male spline 55 formed on the outer peripheral surface of the outer joint member 40, and further the hub wheel 10. They are coupled by caulking the shaft end of the outer joint member 40 projecting from the outer joint member 40. Further, in this bearing device, cylindrical surfaces 77 and 79 are formed on both sides of the male spline 55 of the outer joint member 40 in order to increase bending rigidity and the like, and the cylindrical surfaces 77 and 79 are formed on the female spline 53 on the hub wheel 10 side. It is fitted to the tooth tip surface.
JP-A-11-62951

  In the structure shown in FIG. 12, it is necessary to fit the cylindrical surface and the tooth tip surface of the female spline 53 without rattling. For this reason, high accuracy is required for the cylindrical surface and the tooth tip surface, including coaxiality. To achieve this, it is necessary to significantly increase the processing accuracy of the outer joint member, hub ring, and spline, and there is a concern about cost increase. Is done.

Therefore, an object of the present invention is to suppress a significant cost increase .

In order to achieve the above object, in the present invention, the hub wheel, constant velocity universal joint, and double row bearing are unitized, and at least one of the double row inner races of the bearing serves as an outer joint member of the constant velocity universal joint. in forming the driving wheel bearing apparatus, the inner periphery of the hub wheel, to fit the outer joint member via the torque transmission means comprising serrations or splines, the torque transmission means provided on the outer joint member, the outboard The end of the groove on the outer side has a cut-out structure with a straight shape parallel to the axial direction, and the end on the outboard side of the groove bottom of the torque transmission means provided on the outer joint member is more inward than the end face of the hub wheel. Torque transmitting means disposed on the board side and having a diameter smaller than the groove diameter of the torque transmitting means provided on the outer joint member at the end of the outer joint member on the outboard side and provided on the hub wheel It provided the caulking portion of smaller diameter than the addendum diameter, attached to the outer joint member and the hub wheel by caulking to be caulked portion. In this case, it is sufficient that the fitting portion between the hub wheel and the outer joint member is finished with the same accuracy as that of a normal product, and high accuracy such as the coaxiality is not required unlike the conventional product shown in FIG. Therefore, a significant increase in production cost can be avoided.

In this cut-out structure, if the groove bottom end on the shaft end side of the serration provided on the outer joint member is arranged on the inboard side from the end surface of the hub wheel, concentration of shear load can be avoided. The occurrence of caulking cracks can be prevented.

It is also possible to give a tightening margin to the inboard side end portion of the fitting portion between the torque transmission means provided on the outer joint member and the torque transmission means provided on the hub wheel. As a result, an interference fitting portion is formed at the inboard side end portion of the fitting portion of the torque transmitting means, and the torque is shared also in this portion, so that it is possible to avoid cracking of the crimping portion. Also, relief portions can be provided on the inboard side of the hub wheel on the inboard side from the torque transmission means and on the outboard side of the outer joint surface of the outer joint member, respectively. As a result, the torque transmitting means can be easily processed.

  When the outer joint member and the hub ring are coupled by caulking, the torque transmission means can be satisfied by plastic deformation accompanying the caulking in the vicinity of the caulking portion. By this fulfillment, since the rattling in the circumferential direction between the hub wheel and the outer joint member is reduced, it is possible to increase the coupling strength between the two. The specific means of caulking is arbitrary, but for example, by adopting swing caulking, efficient processing becomes possible.

  This bearing device for a drive wheel has a fitting part in which the above-mentioned caulking part is fitted on one side in the axial direction of the torque transmission means, and the hub wheel and the outer joint member are fitted on the other side without rattling. It is good. In this fitting portion, since the hub wheel and the outer joint member are closely fitted so that they do not rattle, the fitting portion functions as a receiving portion for the radial load.

  Coupling of the outer joint member and the hub wheel by caulking, for example, caulking the shaft end of the outer joint member to engage the hub wheel, or caulking the end of the hub wheel to engage the outer joint member. Can be done.

  Since the shaft end of the stem portion that becomes the crimping portion is a portion that performs crimping, ductility is required. Therefore, it is preferable that the caulking portion has a hardness comparable to that of the material before the heat treatment.

  Of the serration fitting portions of the outer joint member and the hub wheel, it is desirable that at least the side opposite to the shaft end is fitted with a tightening margin. As described above, when the torque transmission means such as serration is satisfied by plastic deformation in the vicinity of the caulking portion, the outer joint member and the hub wheel bite into each other at this sufficient portion, and there is no backlash. The torque sharing at the part increases. On the other hand, if both serrations are fitted with a tightening margin on the side opposite to the shaft end of the outer joint member, torque is shared even in this interference fitting portion, and torque sharing at the sufficient portion is reduced. It is possible to avoid cracking of the fastening portion.

  In this case, the workability at the time of fitting serrations is improved by making the shaft end side of the serration fitting portions a clearance fit.

  As means for securing the tightening allowance, the serration of any one of the outer joint member and the hub ring is inclined with respect to the axial direction, or the serration of either the outer joint member or the hub ring. In this case, the side opposite to the shaft end is inclined with respect to the axial direction, and the shaft end side is formed parallel to the axial direction.

  The torque transmission means is formed by interposing an uneven portion on the fitting surface between the hub wheel and the outer joint member, and caulking the fitting surface by expanding or reducing the diameter at least partially including the uneven portion. You can also In this case, since the concavo-convex portion bites into the mating surface of the mating member, it is possible to transmit torque between the hub wheel and the outer joint member, and ensure the coupling strength between the hub wheel and the outer joint member, It is possible to prevent loosening of the crimped portion for a long period of time. The concavo-convex portion can be provided on either or both of the hub wheel side and the outer joint member side.

  If the concavo-convex part is subjected to a heat treatment by heat treatment, the concavo-convex part is less likely to be crushed and firmly bites into the mating surface on the other side, so that a stronger plastic bond can be realized.

Thus, in the present invention, it is sufficient that the fitting portion between the hub wheel and the outer joint member is finished with the same accuracy as that of a normal product. Therefore, the manufacturing cost does not increase significantly.

  If the bottom end of the groove on the shaft end side of the serration is placed on the inboard side of the end face of the hub wheel, it is possible to avoid concentration of shear load at the crimped part, and caulking cracks occur. Can be prevented, and the coupling strength between the hub wheel and the outer joint member can be increased.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  The drive wheel bearing device shown in FIG. 1 includes a hub wheel 10, a bearing device 20, and a constant velocity universal joint 30 as main components. Here, the side closer to the outside of the vehicle when assembled to the vehicle is referred to as the outboard side, and the left side is the outboard side in each of the above drawings (excluding FIG. 11). On the other hand, the side closer to the center of the vehicle is called the inboard side, and the right side is the inboard side in each figure.

  The hub wheel 10 includes a flange 14 for attaching a drive wheel (not shown) to an end portion on the outboard side, and a hub bolt 15 for fixing the wheel desk at a circumferentially equidistant position of the flange 14 is provided. Implanted. An outboard inner race 12 is formed on the outer peripheral surface of the hub wheel 10 near the flange 14. The hub wheel 10 has an axial through hole 16 in the axial center.

The constant velocity universal joint 30 includes an inner joint member 32 having a track groove 31 on the outer peripheral portion, an outer joint member 40 having a track groove 41 on the inner peripheral portion, and the track groove 31 and the outer joint member of the inner joint member 32. A plurality of balls 34 interposed between the 40 track grooves 41 and a cage 36 for holding all the balls in the same plane. The inner joint member 32 has an axial through-hole 33, which is not shown, but is connected to a drive shaft connected to a constant velocity universal joint disposed on the engine side by serration or the like. . The outer joint member 40 includes a mouth portion 43 and a stem portion 45, and the stem portion 45 is fitted to the inner periphery of the through hole 16 of the hub wheel 10. An inner race 42 on the inboard side is formed on the outer peripheral surface of the mouse portion 43 near the shoulder surface 44 (the inner race 42 is fitted with an outer diameter portion of the outer joint member 40 which is made separately). May be) The shoulder surface 44 of the mouse portion 43 abuts against the end surface of the hub wheel 10, whereby the hub wheel 10 and the outer joint member 40 are positioned in the axial direction, and the dimension between the inner races 12 and 42 is defined. The stem portion 45 is hollow by providing an axial through hole 46 communicating with the bottom of the bowl-shaped mouse portion 43, but may be solid.

  The bearing 20 includes a double row outer member 21 and a double row rolling element 29. The outer member 21 includes a flange 24 for attachment to a vehicle body (not shown), and a double row outer race 22 on which a double row rolling element 29 rolls is formed on the inner peripheral surface. Double row rolling elements 29 are incorporated between the inner race 12 of the hub wheel 10, the inner race 42 of the outer joint member 40, and the double row outer race 22 of the outer member 21. The double row outer race 22 and the inner races 12 and 42, the rolling elements 29 incorporated between both races, and the outer member 21 constitute a bearing 20. Here, the case of a double row angular contact ball bearing using a ball as the rolling element 29 is illustrated, but in the case of a heavy wheel bearing device for automobiles, a double row tapered roller using a tapered roller as the rolling element. A bearing may be employed.

  Seals 26 and 28 are attached to both end openings of the outer member 21 to prevent leakage of grease and lubricating oil filled in the bearing and intrusion of water and foreign matters from the outside. Further, since the through hole 46 of the stem portion 45 communicates with the internal space of the mouse portion 43 as described above, the mouth portion of the through hole 46 is prevented in order to prevent leakage of grease filled in the mouse portion 43. An end plate 38 is attached to the 43 side end. The end plate 38 is preferably made of a light material having good thermal conductivity such as aluminum.

The hub wheel 10 and the outer joint member 40 of the constant velocity universal joint 30 are coupled via a torque transmission means 51. The torque transmission means 51 enables torque transmission between the members 10 and 40 by engaging the unevenness provided on the stem portion 45 of the outer joint member 40 and the unevenness provided on the hub wheel 10 in the circumferential direction. For example, it can be composed of serrations and splines (the following “serration” includes splines). As shown in FIG. 2 in an enlarged manner, the female serration 53 formed on the inner peripheral surface of the hub wheel 10 is formed over substantially the entire region from the substantially central portion in the axial direction of the inner peripheral surface to the end portion on the outboard side. The male serration 55 formed on the outer peripheral surface of the stem portion 45 of the outer joint member 40 is a region that partially fits with the female serration 53 on the hub wheel 10 side, specifically, an inboard side portion of the female serration 53. It is formed only in the area where it fits. Accordingly, a portion of the female serration 53 of the hub wheel 10 on the outboard side becomes a non-fitting region where the male serration 55 of the outer joint member 40 is not fitted. Relief portions for facilitating machining of the serrations 53 and 55 on the inboard side of the female serration 53 on the inner peripheral surface of the hub wheel 10 and on the outboard side of the male serration 55 on the outer peripheral surface of the outer joint member 40, respectively. 57 and 59 are formed.

  On the inboard side of the torque transmission means 51, a fitting portion 61 is provided in which the hub wheel 10 and the outer joint member 40 are fitted without causing radial backlash. In the fitting portion 61, the cylindrical outer peripheral surface of the outer joint member 40 and the cylindrical inner peripheral surface of the hub wheel 10 are fitted with an interference fit, so that the fitting portion 61 is loaded on the hub wheel 10. The radial load can be received by the stem portion 45 of the outer joint member 40.

  Further, the hub wheel 10 and the outer joint member 40 are non-separably plastically coupled in the axial direction by the caulking portion 63. FIG. 2 shows an example in which the shaft end of the outer joint member 40 is swaged and engaged with the hub wheel 10. In this case, the staking is performed at the shaft end on the outboard side of the outer joint member 40 with a small diameter. A cylindrical caulking portion 65 is provided, and this is performed by plastic deformation of the caulking caulking portion 65 toward the outer diameter side by swing caulking, for example. As shown in FIG. 11, the swing caulking is a process of plastically deforming the portion to be caulked 65 while the center axis O1 of the punch 67 is swung with respect to the center axis O2 of the wheel bearing device (slashing motion). .

In this case, since the punch 67 enters deep inside the crimped portion 65 and exerts a pressing force on the outside diameter side even at this deep portion, plastic deformation to the outside diameter side occurs at the base end side of the crimped portion 65 as well. The outer peripheral portion of the outer joint member 40 partially satisfies the unevenness of the torque transmission means 51 (female serration 53) on the hub wheel 10 side in the vicinity of the shaft end (the filling portion 69 is represented by a dotted pattern). That is, the outer peripheral meat portion bites into the vicinity of the end portion on the outboard side of the unevenness (the valley portion or the tooth tip surface of the female serration 53) formed on the inner periphery of the hub wheel 10 and closely adheres to the surface thereof. Therefore, the rattling in the circumferential direction between the hub wheel 10 and the outer joint member 40 is reduced, the rigidity of the wheel bearing device is increased, the feeling during operation is improved, the wear of the torque transmission means 51 is avoided, and the like. Can be achieved. The fitting portion between the hub wheel 10 and the outer joint member 40 only needs to be finished to the same degree of accuracy as a normal product, and high accuracy is required for the coaxiality and the like as in the conventional product shown in FIG. Therefore, a significant increase in production cost can be avoided. Further, since the hub wheel 10 and the outer joint member 40 are in close contact with each other in the sufficient portion 69, the full portion 69 can receive a radial load as in the fitting portion 61. Therefore, it is possible to support the radial load on both axial sides of the torque transmitting means 51 together with the fitting portion 61, and the bending rigidity (moment load capacity) of the entire bearing device is thereby increased.

  In the above description, swing caulking is exemplified as the caulking method, but other caulking methods may be adopted as long as the torque transmission means 51 on the hub wheel 10 side can be satisfied.

  As shown in FIG. 2, a stepped portion 71 whose diameter is increased on the outboard side is provided on the inner periphery of the shaft end of the outer joint member 40 due to the relationship with the inner diameter of the central portion of the shaft. In this case, the region on the outboard side from the stepped portion 71 is plastically deformed to the outer diameter side. In FIG. 2, the stepped portion 71 is disposed in the vicinity of the end face 10a of the hub wheel 10, but in FIG. 3, the stepped portion 71 is disposed further on the inboard side than in FIG. 2, and the plastic deformation region is expanded on the inboard side. I am letting. In this case, since the region of the sufficient portion 69 after crimping is also expanded to the inboard side, a higher padding effect is obtained. FIG. 4 shows an example in which a jig such as a punch 73 is used after swinging and caulking to expand the diameter of the shaft end of the outer joint member 40 so that the shaft end is more firmly satisfied. FIG. 5 shows an example in which the female serration 53 of the hub wheel 10 is cut off on the inboard side rather than reaching the end surface 10a of the hub wheel 10. In this case, since it is necessary to displace the filling portion 69 also to the inboard side, a tool such as a punch 73 is used to enlarge the shaft end of the outer joint member 40 as in FIG. .

  By the way, when caulking the caulking part 65 as described above, it is necessary to take measures against caulking cracks. The caulking crack is a phenomenon in which the caulking portion 63 is cracked during caulking or during use of the bearing after caulking. As a factor, the concentration of deformation distortion can be considered first. In other words, when caulking, due to the difference in rigidity between the shaft end portion of the male serration 55 and the smooth caulking portion 65, the step distortion is concentrated on the boundary portion, and this portion is accompanied by caulking. Since it is greatly deformed, the caulking portion 63 is likely to be cracked.

  As a countermeasure, as shown in FIGS. 6 and 7, for example, the outer periphery of the stem portion 45 (in this embodiment, the outer periphery of the tightened portion 65) is connected to the groove bottom of the male serration 55 on the shaft end side of the male serration 55. In addition to the male serration 55 of the outer joint member 40, the shaft end side (left of the drawing) of the stem 45 has a cut-out structure, and the cut-out portion 52 is formed from the end face 10 a of the hub wheel 10. Also, a structure that is arranged on the inboard side can be considered. Here, the “cut-out structure” means a structure in which the groove bottom 55a of the male serration 55 is cut through straight in parallel to the axial direction and opened in the outer peripheral region of the crimped portion 65. Thus, by arranging the end portion (cut-out portion 52) on the shaft end side of the groove bottom 55a of the male serration 55 on the inboard side with respect to the hub wheel end surface 10a, deformation during caulking is a smooth cylindrical shape. Since it mainly occurs at the portion to be crimped 65, it is possible to reduce the concentration of shear strain and avoid the occurrence of cracks.

  As a second factor of the caulking crack, it is conceivable that the torque sharing at the shaft end of the serration fitting portion 51 becomes excessive. That is, in normal serration fitting, the male / female serration portions 55 and 53 are loosely fitted in the circumferential direction, which causes rattling, but when the female serration 53 is satisfied by plastic flow by caulking as described above. Since the clearance in the circumferential direction between the two serrations 53 and 55 is reduced and there is no backlash, the torque sharing at this portion increases.

  As a countermeasure against this, it is conceivable that the serrations 53 and 55 are fitted with a tightening margin on the opposite side of the shaft end, that is, the inboard side, of the serration fitting portion. As a result, an interference fitting portion is formed at the inboard side end portion of the serration fitting portion, and the torque is also shared in this portion, so that the torque sharing in the sufficiency portion 69 can be reduced and the caulking portion It is possible to avoid 63 cracks.

  As a method of forming an interference fitting portion on the inboard side, for example, it is considered that either one of the male serration 55 and the female serration 53 is slightly inclined with respect to the axis to give the serration a twist angle. It is done. In this case, in addition to tilting over the entire length of the serration, only the inboard side portion may be tilted, and both the serrations 53 and 55 may be formed parallel to the axial direction on the outboard side.

  In addition, it is also possible to prevent caulking cracks by considering the limit value of the strain rate of the caulking portion 63 and determining the limit value of the processing speed during caulking.

  The hub wheel 10 is formed by forging using carbon steel having a carbon content of 0.45 to 0.80% by weight, and starts from the vicinity of the base end portion of the flange 14 to face the seal 26 (seal Surface), the inner race 12, and a region from the abutting surface to the shoulder surface 44 of the outer joint member 40, a hardened layer of about Hv 510 to 900 is formed by heat treatment such as induction hardening. Among these, the end surface of the small end portion of the hub wheel 10 (abutting surface with the shoulder surface 44) is hardened to HRC 50 or more, preferably HRC 58 or more, in order to prevent a decrease in preload due to wear of the end surface. The same hardened layer (Hv 510 to 900) is also formed in the cylindrical inner peripheral surface of the fitting portion 61 and the female serration portion 53 in the inner peripheral surface of the hub wheel 10. Among these, the cylindrical inner peripheral surface of the fitting portion 61 is fretting, abnormal noise, and life reduction of the inner peripheral surface of the fitting portion 61 when a bending moment is applied to the inner races 12 and 42 via the balls 29. Is cured to HRC 50 or more, preferably HRC 58 or more, and the female serration portion 53 can transmit sufficient torque even with a short serration fitting length (about a few tens of millimeters), and wear and wear. Is cured to HRC 50 or more.

  The outer joint member 40 is also formed by forging using carbon steel having a carbon content of 0.45 to 0.80% by weight, similarly to the hub wheel 10, and subjected to heat treatment such as induction hardening. The hardened layer by heat treatment starts from the surface facing the seal 28 (seal surface), and has an Hv of about 510 to 900 in the region extending from the inner race 42, the shoulder surface 44, the fitting portion 61 (cylindrical outer peripheral surface), and the male serration 55. To be formed. On the other hand, since the shaft end of the stem portion 45 (the caulking portion 65) serving as the caulking portion 63 is a portion to be caulked, ductility is necessary. The material hardness (Hv 200 to about 300) is maintained.

  In the above embodiment, the abutting portion between the small-diameter side end surface of the hub wheel 10 and the shoulder surface 44 of the outer joint member 40 is provided so that the axial lengths of the torque transmission means 51 and the fitting portion 16 can be sufficiently secured. It is desirable to provide it on the inboard side with respect to the center line P of the pitch between the balls 29.

  FIG. 8 is an example in which a solid portion 47 is partially formed at the shaft end (left side of the drawing) of the stem portion 45 of the outer joint member 40 in the wheel bearing for driving wheels shown in FIG. The solid portion 47 is for improving the workability when the male serration 55 on the outer periphery of the stem portion 45 is processed by rolling or the like, and the male serration 55 is partially or entirely (for this purpose) A part of the solid portion 47 is included in the outer peripheral region of the solid portion 47.

  FIG. 9 is an example in which an uneven portion 75 is interposed on the fitting surface between the hub wheel 10 and the outer joint member 40, and the fitting surface is partially expanded to include the uneven portion 75 and crimped. is there. The concavo-convex portion 75 is formed, for example, by performing knurling or the like on the outer peripheral surface of the stem portion 45 of the outer joint member 40. For example, the fitting surface is subjected to diameter caulking by press-fitting a caulking jig having an outer diameter larger than the inner diameter of the through-hole 46 into the through-hole 46 and inserting the stem 45 into the outer diameter from the inner diameter side. This is done by expanding the diameter to the side. By this caulking, the uneven portion 75 of the stem portion 45 bites into the inner peripheral surface of the hub wheel 10, so that the hub wheel 10 and the outer joint member 40 are plastically coupled. By the biting of the concavo-convex portion 75, torque can be transmitted between the hub wheel 10 and the stem portion 45, so that the concavo-convex portion 75 also functions as the torque transmitting means 51 of FIG.

  After completion of the above-described diameter expansion caulking, as in FIG. 1, the shaft end of the stem portion 45 protruding from the end surface 10a of the hub wheel 10 is caulked to the outer diameter side by swing caulking or the like to form the hub wheel end surface 10a. By engaging, the concave and convex portion 75 as the torque transmitting means 51 is further satisfied, so that a strong coupling force can be obtained as in FIG.

  In addition to expanding the diameter of the fitting surface in which the concave and convex portions 75 are interposed, the diameter of the fitting surface is reduced, for example, by fitting the hub wheel 10 by reducing the diameter from the outer diameter side to the inner diameter side. The same effect can be obtained by reducing the diameter of the surface. In the uneven portion 75, work hardening occurs due to uneven processing, but if this portion is further subjected to a hardening process by heat treatment such as induction hardening, the uneven portion 75 is hard to be crushed and firmly bites into the mating surface on the other side. A stronger plastic bond is achieved.

  FIG. 10 shows a drive wheel bearing device in which the hub wheel 10 is fitted to the inner periphery of the outer joint member 40. One end (inboard side) of the hub wheel 10 is caulked and the mouth portion of the outer joint member 40 is shown. 43 is an example of engagement with the bottom. Also in this case, as in FIGS. 1 and 6, torque transmission means 51 (FIG. 7 shows the case of serration) is interposed between the hub wheel 10 and the outer joint member 40, and the inner periphery of the outer joint member 40 is inserted. By satisfying the provided female serration by caulking in the vicinity of the caulking portion 63, a strong coupling force can be obtained. Since other configurations and operations are the same as those of the embodiment shown in FIGS. 1 and 6, common members are denoted by the same reference numerals, and redundant description is omitted.

It is sectional drawing of the bearing apparatus for drive wheels concerning this invention. It is sectional drawing to which the fitting part of a hub ring and an outer joint member was expanded. It is sectional drawing to which the fitting part of a hub ring and an outer joint member was expanded. It is sectional drawing to which the fitting part of a hub ring and an outer joint member was expanded. It is sectional drawing to which the fitting part of a hub ring and an outer joint member was expanded. It is sectional drawing to which the fitting part of a hub ring and an outer joint member was expanded. It is the enlarged plan view which expand | deployed the axial end part of the male serration. It is sectional drawing which shows other embodiment of the bearing apparatus for drive wheels. It is sectional drawing which shows other embodiment of the bearing apparatus for drive wheels. It is sectional drawing which shows other embodiment of the bearing apparatus for drive wheels. It is sectional drawing which shows a rocking caulking process. It is sectional drawing which shows an example of the conventional bearing apparatus for drive wheels.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Hub wheel 12 Inner race 20 Bearing 30 Constant velocity universal joint 40 Outer joint member 42 Inner race 51 Torque transmission means 52 Cut-out part 53 Female serration 55 Male serration 55a Groove bottom 61 Fitting part 63 Fastening part 65 Fastening part 75 Uneven part

Claims (3)

In the drive wheel bearing device in which the hub wheel, the constant velocity universal joint, and the double row bearing are unitized, and at least one of the double row inner races of the bearing is formed on the outer joint member of the constant velocity universal joint,
The inner periphery of the hub wheel, to fit the outer joint member via the torque transmission means comprising serrations or splines, the torque transmission means provided on the outer joint member, the groove bottom of the end portion of the outboard side shaft A cut-out structure with a straight shape parallel to the direction, and the end portion on the outboard side of the groove bottom of the torque transmission means provided on the outer joint member is arranged on the inboard side from the end surface of the hub wheel, and the outer joint member A to-be-clamped portion having a diameter smaller than the groove diameter of the torque transmission means provided on the outer joint member and a diameter smaller than the tooth tip diameter of the torque transmission means provided on the hub wheel is provided at the end of the outboard side A drive wheel bearing device , wherein an outer joint member is coupled to a hub wheel by crimping a portion to be crimped . 2. The drive wheel bearing device according to claim 1, wherein an inboard side end portion of a fitting portion between a torque transmission means provided on the outer joint member and a torque transmission means provided on the hub wheel is provided with a tightening margin . The clearance part is provided in the inboard side rather than the torque transmission means among the internal peripheral surfaces of a hub ring, and the outboard side rather than the torque transmission means among the outer peripheral surfaces of an outer joint member, respectively. Drive wheel bearing device.

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