JP2008002580A - Bearing unit for drive wheel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simplify the step of assembling a bearing unit for a drive wheel including a hub wheel, bearings, and constant velocity universal joints into a knuckle member. <P>SOLUTION: The hub wheel 10 is plastically joined to the outer joint member 31 of the outboard side constant velocity universal joint 30. The outer peripheral surface 26a of the external member 26 is press-fitted to the inner peripheral surface of the knuckle member. The maximum outer diameter dimension D1 of the outboard side constant velocity universal joint 30 is smaller than the minimum inner diameter dimension Dn of the knuckle member 6. A relief part 56 is formed on the outer peripheral surface 26b of the external member 26. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a bearing unit for driving wheels (front wheels of FF vehicles, rear wheels of FR vehicles, all wheels of 4WD vehicles) of automobiles.

  As shown in FIG. 20, the drive shaft 1 that transmits the power from the engine to the drive wheels includes a fixed type constant velocity universal joint J1 on the outboard side (the side of the vehicle body in the vehicle width direction) and the inboard side ( The intermediate shaft 2 is connected to a sliding type constant velocity universal joint J2 on the vehicle center side in the vehicle width direction. The constant velocity universal joint J1 on the outboard side is coupled to the hub wheel 4 rotatably supported by the wheel bearing 3, and the constant velocity universal joint J2 on the inboard side is coupled to the differential 5.

  The wheel bearing 3 is arranged in double rows between a bearing inner ring 3a fixed to the outer periphery of the hub wheel 4, a bearing outer ring 3b fixed to a knuckle member 6 extending from a suspension on the vehicle body side, and a bearing inner ring 3a and a bearing outer ring 3b. And rolling elements 3c. Usually, both are fixed by press-fitting the bearing inner ring 3 a on the outer periphery of the hub ring 4. The bearing outer ring 3b and the knuckle member 6 are usually fixed by bolting the flange 3b1 of the bearing outer ring 3b to the knuckle member 6.

The conventional assembly of the drive shaft 1 to the vehicle is performed in a state where the hub wheel 4 and the wheel bearing 3 are fixed to the knuckle member 6 in advance, and the shaft end on the outboard side of the drive shaft 1 (the stem portion 7a of the outer joint member 7). ) Is inserted into the inner periphery of the hub wheel 4 and a nut 8 is screwed onto the shaft end protruding from the hub wheel 4 (see, for example, Patent Document 1). As the nut 8 is tightened, the entire drive shaft 1 slides toward the outboard side, and the shoulder 7b of the outer joint member 7 comes into contact with the end surface of the bearing inner ring 3a. As a result, the outer joint member 7 and the hub wheel 4 are positioned in the axial direction, and a predetermined preload is applied to the wheel bearing 3. The outer peripheral surface of the stem portion 7a of the outer joint member 7 and the inner peripheral surface of the hub wheel 4 are coupled by a spline (not shown), and the driving force of the engine transmitted to the outer joint member 7 is the spline and further the hub wheel 4 It is transmitted to the wheel via.
JP 2004-270855 A

  However, in the above-described conventional process, the knuckle member 6 assembled with the wheel bearing 3 and the hub wheel 4 is made to wait in advance at a position rotated from the neutral position around the kingpin center, and in this state, the outboard side constant velocity universal joint The complicated work of fixing J1 to the hub wheel 4 and further fixing the inboard side constant velocity universal joint J2 to the differential 5 after returning the knuckle member 6 to the neutral position is required. In addition, many fastening operations such as bolting of the bearing outer ring 3b to the knuckle member 6 and tightening of the nut 8 are required. Therefore, the assembly process of the drive shaft is complicated, and this point is a factor of high cost. Moreover, many nuts and bolts are required, and the number of parts is also disadvantageous in terms of cost. Further, since the drive shaft turns with the turning of the knuckle member, a large work space is required.

  By the way, the tightening operation of the nut can be omitted by previously connecting and integrating the outer joint member 7 of the outboard side constant velocity universal joint J1 and the hub wheel 4. However, since a large load acts on the joint between the two, including the moment load during cornering, as the vehicle travels, the joint structure has a high strength that can withstand this and is inexpensive. Needed.

  Therefore, the main object of the present invention is to simplify the process of assembling the drive wheel bearing unit including the hub wheel, the bearing, and the constant velocity universal joint to the knuckle member.

  In order to achieve the above object, the present invention provides an outer member having a plurality of outer races on the inner periphery, an inner member having a plurality of inner races facing the outer races, and an outer member and an inner race facing each other. In a drive wheel bearing unit comprising a plurality of rows of rolling elements, a hub wheel attached to a wheel, and an outboard side constant velocity universal joint, the outer peripheral surface of the outer member is connected to the inner side of the knuckle member on the vehicle body side. The outer surface was fitted and assembled, the maximum outer diameter of the constant velocity universal joint on the outboard side was made smaller than the minimum inner diameter of the knuckle member, and a nut portion was provided on the outer peripheral surface of the outer member. Here, the term “constant velocity universal joint” includes accessories such as boots and boot bands (hereinafter the same). The maximum outer diameter of the outboard constant velocity universal joint including these accessories is set smaller than the minimum inner diameter of the knuckle member.

  With this configuration, the outer unit of the constant velocity universal joint on the outboard side and the hub wheel are coupled, and the outer member is assembled and fitted from the outboard side to the knuckle member, thereby fixing the bearing unit to the knuckle member. It becomes possible to do. Such an operation can be performed simply by pushing the bearing unit in the direction of the axle, and there is basically no need to bolt the outer member to the knuckle member. Therefore, the work of assembling the bearing unit to the vehicle can be simplified.

  By forming the pussies on the outer peripheral surface of the outer member, it is possible to control the range of action of the compressive force generated during press-fitting into the knuckle member. For example, when the seal member is fixed to the inner peripheral surface of the outer member, the pussies can be formed in the outer diameter side region of the seal member. Further, the press-fitting area can be reduced by providing the Nusumi portion in the outer diameter region between the outer race on the inboard side and the outer race on the outboard side.

  ADVANTAGE OF THE INVENTION According to this invention, the assembly | attachment process to the vehicle of the bearing unit for drive wheels containing a hub wheel, a bearing, and an outboard side constant velocity universal joint can be simplified. By forming the nose portion of the outer member in the outer diameter side region of the seal member, it is possible to prevent the compressive force from the outer member due to press fitting from acting on the seal member. For this reason, the sealing member exhibits a stable sealing effect without being damaged. In addition, by providing the Nusumi part in the outer diameter area between the outer race on the inboard side and the outer race on the outboard side, the press-fitting area can be reduced, improving the press-fitting workability, Preloading can be reliably performed.

  Embodiments of a drive wheel bearing unit according to the present invention will be described in detail below.

  The drive wheel bearing unit shown in FIG. 1 includes a hub wheel 10, a bearing portion 20, and an outboard side constant velocity universal joint 30.

  The hub wheel 10 includes a wheel mounting flange 11 for mounting a wheel (not shown) on its outer peripheral surface. A plurality of female screws 12 are formed in the circumferential direction of the wheel mounting flange 11, and wheel bolts (not shown) for fixing an oil and a disk are screwed into the female screws 12. An inner ring 28 is press-fitted into the small-diameter step 13 formed on the outer peripheral surface of the hub ring 10 with an appropriate tightening allowance. A retaining ring 29 is interposed between the inner circumferential surface of the inner ring 28 and the outer circumferential surface of the small diameter step portion 13, and the positioning of the inner ring 28 and the hub wheel 10 in the axial direction is performed by the retaining ring 29. The hub wheel 10 is manufactured by turning or forging.

  The bearing portion 20 has a double-row angular ball bearing structure arranged on the back surface, a double-row inner race 21 and an outer race 22, a rolling element 23 disposed between the inner race 21 and the outer race 22 facing each other, and an outboard side ( The holder 24 holds the rolling element row on the left side of the drawing and the rolling element row on the inboard side (right side of the drawing) at equal intervals in the circumferential direction. In the illustrated example, the inner race 21 on the outboard side is formed on the outer peripheral surface of the hub wheel 10, and the inner race 21 on the inboard side is formed on the outer peripheral surface of the inner ring 28. In this case, the hub wheel 10 and the inner ring 28 constitute an inner member 25 having a double row inner race.

  The outer race 22 is formed on the inner peripheral surface of the ring-shaped integrated outer member 26. In addition, a gusset portion 56 is formed at both axial end portions of the outer peripheral surface 26a of the outer member 26, and thereby, between the inner peripheral surface 6a of the opposing knuckle member 6 and the outer peripheral surface 26a of the outer member 26. A gap 55 is formed. The outer peripheral surface 26a of the outer member 26 is a cylindrical surface having a uniform diameter as a whole, without the Nusumi portion 56. That is, in this drive wheel bearing unit, unlike the conventional outer member, the flange for attaching to the knuckle member 6 is not provided.

  Seal members 27a and 27b are press-fitted and fixed to the inner peripheral surfaces at both axial ends of the outer member 26. For this reason, the Nusumi portion 56 is provided corresponding to the outer diameter side region of the seal member 27. A gap 55 is formed between the inner peripheral surface 6a of the opposite knuckle member 6 and the outer peripheral surface 26a of the outer member 26 also by forming a nuisance portion (not shown) on the inner peripheral surface 6b of the knuckle member 6. can do.

The seal member 27a on the outboard side has a configuration in which a core metal is covered with an elastic material such as rubber and a plurality of (for example, three) seal lips are formed on the inner diameter side. It is fixed to the outer member 26 by press-fitting into The seal lip is in contact with the outer peripheral surface of the hub wheel 10 and the inboard side end surface of the flange portion 11.

  The inboard-side seal member 27b is called a cassette seal, and has a configuration in which a plurality of (for example, three) seal lips formed on the inner diameter side of the cored bar are brought into contact with an inverted L-shaped slinger. The seal member 27b is fixed to the opening by pressing the cored bar into the inner peripheral surface of the outer member 26 and pressing the slinger into the outer peripheral surface of the inner ring 28. The seal members 27a and 27b seal the opening portions at both ends of the bearing portion 20 so as to prevent leakage of grease filled inside and entry of water and foreign matters from the outside.

  In the illustrated bearing portion 20, a ball is illustrated as the rolling element 23, but a tapered roller can be used as the rolling element 23 when the vehicle weight increases.

  The outboard-side constant velocity universal joint 30 is provided at one end of the intermediate shaft 2 on the outboard side, and has an outer joint member 31 having a track groove formed on the inner peripheral surface, and a track facing the track groove of the outer joint member 31. An inner joint member 32 having a groove formed on the outer peripheral surface, a torque transmission ball 33 incorporated between a track groove of the outer joint member 31 and a track groove of the inner joint member 32, and the outer joint member 31 and the inner joint member. And a cage 34 that is interposed between them and holds the torque transmission balls 33 at equal intervals in the circumferential direction. The inner joint member 32 is coupled to the shaft end on the outboard side of the intermediate shaft 2 inserted in the inner periphery thereof via a serration 35.

  The outer joint member 31 is manufactured by forging, for example, and includes a mouth portion 31a that houses the inner joint member 32, the cage 34, and the torque transmission ball 33, and a solid stem portion 31b that extends integrally from the mouth portion 31a in the axial direction. Have A large-diameter open end and a small-diameter open end of a bellows-shaped boot 37 are fixed to the outer peripheral surface of the mouth portion 31a and the outer peripheral surface of the intermediate shaft 2 via a boot band 36, respectively. Thus, by covering the space between the outer joint member 31 and the intermediate shaft 2 with the boot 37, it is possible to prevent a situation where grease leaks to the outside or foreign matters such as water and dust enter the joint. is doing.

  The stem portion 31b of the outer joint member 31 is coupled to the hub wheel 10 by various coupling structures described later. As the coupling method, a reversible coupling method using a nut may be employed, but preferably, the hub wheel 10 and the outer joint member 31 are not allowed to be reversibly separated and coupled. It is desirable to adopt a structure.

  When the hub wheel 10 and the outer joint member 13 are connected in a non-separable manner, the shoulder surface 38 of the outer joint member 31 is brought into contact with the end surface on the inboard side of the inner ring 28, and the end surface on the outboard side of the inner ring 28 is also a hub. By abutting with the wheel 10 in the axial direction, the interval between the double-row inner races 21 is maintained at a specified dimension, and a preload (preliminary preload) is applied.

  In the present invention, the outer peripheral surface of the outer member 26 is fitted and incorporated into the inner peripheral surface 6a of the knuckle member 6 on the vehicle body side.

  As used herein, fitting and fitting means that the fitting of the outer member 26 and the knuckle member 6 completes the fitting of both. This incorporation can be performed, for example, by press-fitting the cylindrical outer peripheral surface 26a of the outer member 26 into the cylindrical inner peripheral surface 6a of the knuckle member 6 from the outboard side.

  If necessary, the inboard side end of the inner peripheral surface 6a of the knuckle member 6 is provided with a convex portion 6b that engages with the end surface of the outer member 26 in the axial direction. Alternatively, as shown in FIG. 6, a retaining ring 53 is interposed between the outer peripheral surface of the outer member 26 and the inner peripheral surface 6 a of the knuckle member 6. By using these convex portions 6b and retaining rings 53, the effect of preventing the outer member 26 and the knuckle member 6 from coming off is further enhanced. When both the retaining ring 53 and the convex portion 6b are provided, the inboard side end surface of the outer member 26 press-fitted from the outboard side is in contact with the convex portion 6b, and at the same time, formed on the inner peripheral surface 6a of the knuckle member 6. The retaining ring groove 6c and the retaining ring groove 26b formed on the outer peripheral surface 26a of the outer member 26 are opposed to each other, and the retaining ring 53 accommodated in the retaining ring groove 26b of the outer member 26 is elastically expanded in diameter, thereby the knuckle member. 6 and the outer member 26 are engaged in the axial direction.

  When sufficient fixing force can be obtained only by press-fitting, the retaining ring 53 can be omitted as shown in FIG. 1 and the like, and the convex portion 6b can also be omitted as shown in FIG. Further, the retaining ring 29 between the hub wheel 10 and the inner ring 28 can be omitted.

  When the retaining ring 53 is used, it is desirable to dispose the retaining ring 53 on the outboard side as much as possible. Specifically, it is desirable to dispose a retaining ring 53 on the outboard side with respect to the axial center line O between the inboard side rolling element 23 and the outboard side rolling element 23. Thus, when the outer member 26 is press-fitted, the sliding distance of the retaining ring 53 relative to the knuckle member inner circumferential surface 6 a can be shortened, so that the knuckle member inner circumferential surface 6 a can be prevented from being damaged by dragging the retaining ring 53. it can.

  Thus, by providing a press-fit surface on the outer peripheral surface 26a of the outer member 26 and press-fitting and fixing the outer member 26 to the inner periphery of the knuckle member 6, the outer member with a flange can be attached to the knuckle member as in the prior art. Compared with the case of bolting to a plurality of locations, the bolt fastening operation can be omitted, and the number of parts and the number of work steps can be reduced accordingly, thereby reducing the cost.

  In addition, by pressing the outer member 26 into the knuckle member 6, radial contraction force acts on the outer member 26 after press-fitting, and the bearing gap is reduced by the contraction force. Accordingly, if the press-fitting allowance is appropriately set in consideration of the preliminary preload amount, an appropriate amount of negative gap (for example, 0 to 100 μm, preferably 0 to 30 μm) can be obtained after press-fitting. In this case, since the preload application work by tightening the nut is not necessary, the assembly workability of the bearing unit can be further improved. If the positive clearance is larger than 0, the bearing rigidity is insufficient and the durability is lowered, and if the negative clearance exceeds 100 μm, the preload is excessively increased, causing abnormal heat generation. Is a problem.

  In such fitting and incorporation, the maximum outer diameter D1 of the outboard side constant velocity universal joint 30 is made smaller than the minimum inner diameter Dn of the knuckle member 6 (D1 <Dn). As a result, first, the outboard side constant velocity universal joint 30 is inserted into the inner periphery of the knuckle member 6, and then the outer member 26 of the bearing portion 20 is press-fitted into the inner periphery of the knuckle member 6. The bearing portion 20 and the outboard side constant velocity universal joint 30 can be assembled to the vehicle in a state of being assembled in advance. At the time of this assembly, the pushing direction of the assembly is constant, so that the workability at the time of assembly is also good.

  Here, the “minimum inner diameter dimension Dn” of the knuckle member 6 means the inner diameter dimension of the portion of the knuckle member 6 that is present on the innermost diameter side. When the convex portion 6b is provided on the inner peripheral surface of the knuckle member 6 as in the first embodiment shown in FIG. 1, the second embodiment shown in FIG. 2, and the third embodiment shown in FIG. Is the “minimum inner diameter dimension”. When the convex portion 6b is omitted as shown in FIG. 6, the inner peripheral surface 6a of the knuckle member 6 has a “minimum inner diameter dimension”.

  Further, the “maximum outer diameter dimension D1” of the outboard side constant velocity universal joint refers to the outer diameter dimension of the portion existing on the outermost diameter side in a state including accessories such as the boot 37 and the boot band 36. For example, in the outboard-side constant velocity universal joint 30 shown in FIG. 1, the outer diameter of the boot maximum diameter portion 37 a is the maximum outer diameter D1 of the outboard-side constant velocity universal joint 30.

  In addition, as shown in FIG. 4, if the maximum outer diameter D2 of the inboard constant velocity universal joint 40 of the drive shaft 1 is made smaller than the minimum inner diameter Dn of the knuckle member 6 (D2 <Dn), the drive shaft 1 Even in a state in which the hub wheel 10 and the bearing portion 20 are assembled in advance (hereinafter referred to as a drive shaft assembly), it can be assembled to the vehicle. That is, the drive shaft assembly is sequentially inserted into the inner periphery of the knuckle member 6 in the order of the inboard side constant velocity universal joint 40, the intermediate shaft 2, and the outboard side constant velocity universal joint 30, and then the outer peripheral surface 26a of the outer member 26. Is pressed into the inner peripheral surface of the knuckle member 6 to complete the assembly to the vehicle. Thereby, the work man-hour at the assembly work site can be reduced, and workability is enhanced. In this case, it is not necessary to turn the knuckle member 6 as in the conventional process, so that the work space is minimized. The maximum outer diameter D2 of the inboard side constant velocity universal joint 40 is the same as that of the outboard side constant velocity universal joint 30, and the inboard side in a state including accessories such as the boot 37 and the boot band 36. This means the maximum outer diameter of the quick universal joint 40.

  As described above, in the drive wheel bearing unit shown in FIG. 1, the Nusumi portion 56 is formed on the outer peripheral surface 26 a of the outer member 26, so that the operating range of the compressive force generated when press-fitting into the knuckle member 6 is controlled. It becomes possible. That is, by forming the Nusumi portion 56 in the outer diameter side region of the seal members 27a and 27b, it is possible to prevent the compressive force from the outer member 6 caused by press-fitting from acting on the seal members 27a and 27b. For this reason, the sealing member exhibits a stable sealing effect without being damaged.

  By the way, the press-fitting allowance between the outer member 26 and the knuckle member only needs to be secured in the outer diameter side region of the outer race 22, so that the outer diameter side between the outer races 22 is further increased as shown by a broken line in FIG. 5. A nuisance part 57 may be formed in the region. Thus, by providing the Nusumi portion 57 in the outer diameter region between the outer race 22 on the inboard side and the outer race 22 on the outboard side, the press fit area is reduced and the press fit workability is improved. The preload can be reliably applied to the.

  When the outer member 26 is press-fitted, if the press-fitting allowance is set uniformly on the outer diameter side of each outer race 22, the amount of preload applied to the bearing portion 20 can be stabilized.

  The hub wheel 10 and the outer joint member 31 are plastically coupled. In this plastic coupling, the male part 51 is formed on one of the hub wheel 10 and the outer joint member 31, and the male part 51 and the deformed female part 52 are formed on the other member. The male part 51 and the female part 52 are pressed into each other. FIG. 1 illustrates a case where the male part 51 is formed on the stem part 31 b of the outer joint member 31 and the female part 52 is also formed on the inboard side end part of the hub wheel 10. One of the male part 51 and the female part 52 is formed in a perfect circle shape in cross section, and the other is formed in a non-circular shape in cross section. FIG. 7A illustrates, as an example, a case where the male part 51 is formed in a tooth-shaped surface such as serration and the female part 52 is formed in a cylindrical surface shape. The male part 51 having a non-circular cross section can be formed efficiently and accurately by forging or rolling.

  In addition, as the shape of the male part 51, a rectangular tube surface can be adopted as shown in FIG. Regardless of the shape, the inner diameter dimension Df of the female part 52 having a perfectly circular cross section is larger than the diameter of the circle A inscribed in the cross-sectional outline of the male part 51 and smaller than the diameter of the circumscribed circle B.

  By press-fitting the male part 51 having the above shape into the inner periphery of the female part 52, plastic flow is generated in the joint part, and all or part of the gap between the two parts is satisfied. Thereby, the hub wheel 10 and the outer joint member 31 are plastically coupled and integrated.

  As shown in FIG. 9, after press-fitting, if the flange portion 58 is formed by caulking the outer peripheral portion (shown by a broken line) of the solid shaft end of the stem portion 31b with a caulking tool 59, the hub wheel 10 is prevented from coming off. The effect is further increased. If sufficient bonding strength can be obtained only by press-fitting, this caulking step can be omitted.

  In this bonded structure, it is desirable to heat-treat the male part 51 having a non-circular cross section in advance so that the surface layer H is harder than the female part 52 as shown in FIG. Thereby, the deformation of the male part 51 due to the press-fitting is suppressed, and the male part 51 easily bites into the female part 52, so that the coupling strength can be further increased. When the caulking process shown in FIG. 9 is performed, the shaft end portion of the stem portion 31b to be plastically deformed by caulking is not quenched, and the flange portion 58 can be easily formed. As a heat treatment method for the male part 51, induction hardening in which the quenching range and the quenching depth are easily controlled is desirable. The female part 52 is basically a raw material not subjected to heat treatment, but may be subjected to heat treatment as long as the surface hardness of the male part 51 is not exceeded.

  In the above description, the case where the male part 51 is formed in a non-circular shape in cross section and the female part 52 is formed in a circular shape in cross section has been exemplified. The male part 51 may be formed in a perfect circle shape in cross section, and the female part 52 may be formed in a non-circular shape in cross section. The female part 52 having a non-circular cross section can be formed by broaching, for example. In this case, the female part 52 having a non-circular cross section is formed with a higher hardness than the male part 51 having a circular cross section.

  By the way, when the male part 51 is press-fitted into the female part 52, the hub wheel 10 is slightly deformed in the diameter increasing direction, and the influence may be exerted on the inner race 21. In order to avoid such a situation as much as possible, it is preferable to arrange the press-fitting portions of both on the axial center line O of the rolling elements 23 on the inboard side and the outboard side as shown in FIG.

  As the drive wheel bearing unit, as shown in FIGS. 11 to 17, the inner race 21 on the outboard side is formed on the outer peripheral surface of the hub wheel 10, and the inner race 21 on the inboard side is formed on the outer periphery of the outer joint member 31. A type formed on the surface can also be used. 11 to 17, the hub wheel 10 and the outer joint member 31 are non-separably coupled, and the shoulder surface 38 and the end surface of the outer joint member 31 are in contact with the hub wheel 10 in the axial direction. The dimension between the inner races 21 in the row is defined, and a preliminary preload is applied to the bearing portion 20. In this case, the hub wheel 10 and the outer joint member 31 constitute the inner member 25 having the double-row inner race 21.

  11 which shows 4th Embodiment among FIGS. 11-17, the hub ring 10 and the outer joint member 31 are plastically connected by diameter expansion caulking. In the expanded caulking, the stem portion 31b of the outer joint member 31 is formed hollow, and a small-diameter portion 31b1 having an inner diameter smaller than that of the other portion is formed at the end portion on the outboard side. After the stem portion 31b is inserted into the inner periphery of the hub wheel 10, a mandrel having a diameter larger than the inner diameter of the small diameter portion 31b1 is pushed into the inner periphery of the stem portion 31b to increase the diameter of the small diameter portion 31b1, and the inner diameter of the hub wheel 10 is increased. The hub wheel 10 and the outer joint member 31 are plastically coupled by being brought into pressure contact with the peripheral surface. If the concavo-convex portion 15 is formed in advance on the inner peripheral surface of the hub wheel 10 by knurling or the like and the concavo-convex portion 15 is hardened by heat treatment, the concavo-convex portion 15 is formed on the outer peripheral surface of the stem portion 31b by expanding the small diameter portion 31b1. Thus, the hub wheel 10 and the outer joint member 31 can be firmly plastically coupled.

  In addition, when the stem portion 31b of the outer joint member 31 is formed to be hollow as in diameter expansion caulking, the inside of the stem portion 31b is avoided in order to avoid a situation such as entry of foreign matter into the mouth portion 31a and outflow of grease. It is desirable to attach a cap 39 to the peripheral surface.

  FIG. 12 showing the fifth embodiment is a non-separated connection of the hub wheel 10 and the outer joint member 31 by a method called swing caulking. In the swing caulking, the shaft end on the outboard side of the stem portion 31b is formed in a cylindrical shape, and the flange 31b2 is formed by plastically deforming the cylindrical portion to the outer diameter side by swinging the caulking tool. The flange 31b2 is brought into contact with the end surface of the hub wheel 10 to prevent the hub wheel 10 from coming off, and the spline 60 is formed between the inner peripheral surface of the hub wheel 10 and the outer peripheral surface of the stem portion 31b. Thus, the hub wheel 10 and the outer joint member 31 are prevented from rotating.

  FIG. 13 showing the sixth embodiment is one in which the hub wheel 10 and the outer joint member 31 are joined in a non-separable manner by welding (the welded portion is indicated by reference numeral 61). Examples of the welding method include laser beam welding, plasma welding, electron beam welding, and high-speed pulse projection welding. Since the stem portion 31b is press-fitted into the inner periphery of the hub wheel 10 and torque can be transmitted through the press-fitting fitting surface, the load applied to the welded portion 61 is small. Less welding method can be adopted.

  11 to 13 exemplify the case where the stem portion 31b is fitted to the inner periphery of the hub wheel 10, conversely, the hub wheel 10 is fitted to the inner periphery of the hollow stem portion 31b. The two can also be joined in a non-separable manner (see FIGS. 14 to 17).

  Among these, FIG. 14 which shows 7th Embodiment forms the male part 51 and the female part 52 in a different shape mutually like the embodiment shown in FIG. 1, and press-fits the male part 51 in the female part 52, The hub wheel 10 and the outer joint member 31 are plastically coupled. In this case, a male part 51 is formed on the outer peripheral surface of the solid end part 16 on the inboard side of the hub wheel 10, and a female part 52 is formed on the inner peripheral surface of the stem part 31 b facing this. Similarly to the embodiment shown in FIG. 1, after the male portion 52 is press-fitted, the outer peripheral portion of the solid shaft end 16 of the hub wheel 10 is crimped by the method shown in FIG. 9 to form the flange portion 58. Bond strength can be increased.

  FIG. 15 showing the eighth embodiment is one in which the hub wheel 10 and the outer joint member 31 are plastically coupled by the above-described diameter expansion caulking. That is, the small diameter portion 31b1 of the hollow hub wheel 10 is expanded and deformed by a mandrel, and the concave and convex portion 15 formed on the inner peripheral surface of the stem portion 31b is bitten so that the hub wheel 10 and the outer joint member 31 are plastically coupled. . FIG. 16 showing the ninth embodiment is one in which the hub wheel 10 and the outer joint member 31 are plastically coupled by the above-described swing caulking. A cylindrical portion formed at the solid shaft end 16 on the inboard side of the hub wheel 10 is plastically deformed by swinging and caulking to form a flange 17, which is in close contact with the mouth portion 31a. FIG. 17 showing the tenth embodiment is obtained by joining both members in a non-separated manner by the above-described welding method (the welded portion is indicated by reference numeral 61).

  2 and 3 show other configurations of the drive wheel bearing unit. Among these, in the bearing unit shown in FIG. 2, the double row inner races 21 of the bearing portion 20 are all formed on the outer peripheral surface of the integral inner ring 28 press-fitted into the outer periphery of the hub wheel 10. In this case, the inner ring 28 constitutes the inner member 25 having the double-row inner race 21. FIG. 3 shows an example in which the integral inner ring 28 shown in FIG. 2 is divided into two in the axial direction and press-fitted into the outer peripheral surface of the hub wheel 10 to form inner races 21 on the outer peripheral surfaces of the two inner rings 28a and 28b. It is. In this configuration, the two inner rings 28 a and 28 b constitute the inner member 25 having the double-row inner race 21. In any of the bearing units shown in FIG. 2 and FIG. 3, both end openings of the bearing portion 20 are sealed with seal members 27a and 27b.

  Except for the points described above, the configuration of the bearing unit shown in FIG. 2 and FIG. 3 is the same as the configuration of the bearing unit shown in FIG. The description of the overlapping part is omitted.

  FIG. 18 illustrates an example in which the hub wheel 10 and the outer joint member 31 are coupled to each other at the end portion on the outboard side in the bearing units illustrated in FIGS. In FIG. 18, the left column (reference numerals 1, 4, 7) represents the bearing unit equivalent shown in FIG. 1, and the middle column (reference numerals 2, 5, 8) represents the bearing unit equivalent shown in FIG. The right column (reference numerals 3, 6 and 9) in the column represents the bearing unit equivalent product shown in FIG. Further, the upper row (reference numerals 1 to 3) represents the one to which the diameter expansion caulking is applied, the middle row (reference numerals 4 to 6) represents the one to which the swing caulking is applied, and the lower row (reference numerals 7 to 9). Represents the one to which welding is applied.

  In FIGS. 1 to 3, the hub wheel 10 and the inner rings 28, 28 a, 28 b are positioned by the retaining ring 29, but they can also be positioned by swing caulking instead. FIG. 10 shows an example of this, by extending the cylindrical shaft end of the small-diameter step 13 of the hub wheel 10 over the inboard side end surface of the inner ring 28 and swinging the crimping tool on the inner diameter side of the protruding portion. The flange 17 is formed by plastically deforming the protruding portion toward the outer diameter side. The flange 17 is in close contact with the end face on the inboard side of the inner ring 28. In the bearing unit shown in FIGS. 2 and 3 as well, the hub ring 10 and the inner rings 28, 28 a, 28 b can be positioned in the axial direction by similarly performing rocking caulking to form the flange 17.

  FIG. 19 shows an eleventh embodiment. This bearing unit for a drive wheel is an example in which a cylindrical pilot portion 72 fitted to the inner periphery of the wheel 80 is provided on a member different from the hub wheel 10, for example, the brake rotor 70. The brake rotor 70 is disposed between the end surface on the outboard side of the flange 11 of the hub wheel 10 and the wheel 80, and holes 71 for inserting wheel bolts are formed at a plurality of locations in the circumferential direction.

  As shown in FIG. 1, the pilot portion 72 is usually formed integrally with the end portion on the outboard side of the hub wheel 10, and therefore the shape of the hub wheel 10 is complicated. Therefore, in practice, it is difficult to form the hub wheel 10 only by forging, and turning is often performed. Further, the pilot portion 72 needs to be partially rust-proofed. From the above, the manufacturing cost of the hub wheel 10 tends to increase.

  On the other hand, if the pilot portion 72 of the hub wheel 10 is eliminated and is provided at, for example, the inner diameter end portion of the brake rotor 70 as shown in FIG. 19, the shape of the hub wheel 10 on the outboard side is simplified. Therefore, it becomes possible to forge-mold this, and the antirust coating process to the hub wheel 10 is also unnecessary. Therefore, the cost of the hub wheel 10 can be reduced, and a light weight design can be achieved. Since the brake rotor 70 is usually formed by casting, the brake rotor 70 having the pilot portion 72 can be manufactured at low cost.

  FIG. 19 shows a bearing unit equivalent to FIG. 1 in which the inner member 25 is formed by the hollow hub wheel 10 and the inner ring 28, but a similar configuration is shown in FIG. 2 in which the inner member 25 is formed by the integrated inner ring 28. A corresponding bearing unit and a bearing unit corresponding to FIG. 3 in which the inner member 25 is formed by the divided inner rings 28a and 28b can also be employed.

  In each of the embodiments, in the drive wheel bearing unit, the outer member 26 is provided with the puss 56 at both ends in the axial direction of the outer peripheral surface 26a. Can do. Of course, in each of the embodiments, the drive wheel bearing unit may also be provided with the urging portion 57 in the outer diameter region between the outer race 22 on the inboard side and the outer race 22 on the outboard side.

It is sectional drawing of the bearing unit for drive wheels which shows 1st Embodiment of this invention. It is sectional drawing of the bearing unit for drive wheels which shows 2nd Embodiment of this invention. It is sectional drawing of the bearing unit for drive wheels which shows 3rd Embodiment of this invention. It is sectional drawing of a drive shaft. It is sectional drawing which expands and shows the press fit part of an outward member and a knuckle member. It is sectional drawing which shows the modification of the bearing unit for drive wheels of the said FIG. (A) The figure is sectional drawing of the male part in the coupling | bond part of a hub ring and an outer joint member, (b) Figure is sectional drawing of a female part similarly. It is sectional drawing which shows the other structural example of a male part. It is sectional drawing which shows the plastic coupling process of a hub ring and an outer joint member. It is principal part sectional drawing which shows the other modification of the wheel bearing unit for drive wheels of FIG. It is sectional drawing of the bearing unit for drive wheels which shows 4th Embodiment of this invention. It is sectional drawing of the bearing unit for drive wheels which shows 5th Embodiment of this invention. It is sectional drawing of the bearing unit for drive wheels which shows 6th Embodiment of this invention. It is sectional drawing of the bearing unit for drive wheels which shows 7th Embodiment of this invention. It is sectional drawing of the bearing unit for drive wheels which shows 8th Embodiment of this invention. It is sectional drawing of the bearing unit for drive wheels which shows 9th Embodiment of this invention. It is sectional drawing of the bearing unit for drive wheels which shows 10th Embodiment of this invention. It is a figure which shows the structure at the time of applying diameter expansion caulking, rocking caulking, and welding in the bearing unit shown in FIGS. It is sectional drawing of the bearing unit for drive wheels which shows 11th Embodiment of this invention. It is sectional drawing which shows schematic structure around the suspension apparatus of a vehicle.

Explanation of symbols

6 Knuckle member 6a Inner peripheral surface 10 Hub wheel 21 Inner race 22 Outer race 23 Rolling element 25 Inner member 26 Outer member 26a Outer peripheral surface 27a Seal member 27b Seal member 30 Outboard side constant velocity universal joint 56 Nusumi part 57 Nusumi part Dn Minimum inner diameter of knuckle member D1 Maximum outer diameter of constant velocity universal joint on outboard side D2 Maximum outer diameter of constant velocity universal joint on inboard side

Claims (3)

An outer member having a plurality of outer races on the inner periphery, an inner member having a plurality of inner races facing the outer races, a plurality of rows of rolling elements disposed between the outer races and the inner races facing each other, and wheels In a drive wheel bearing unit comprising a hub wheel attached to an outboard and a constant velocity universal joint on the outboard side,
The outer peripheral surface of the outer member is fitted and incorporated into the inner peripheral surface of the knuckle member on the vehicle body side, and the maximum outer diameter of the constant velocity universal joint on the outboard side is made smaller than the minimum inner diameter of the knuckle member. A bearing unit for a drive wheel, characterized in that a Nusumi portion is provided on the outer peripheral surface.   The drive wheel bearing unit according to claim 1, wherein a seal member is fixed to an inner peripheral surface of the outer member, and the squeezed portion is provided in an outer diameter side region of the seal member. The drive wheel bearing unit according to claim 1, wherein the Nusumi portion is provided in an outer diameter side region between the outer race on the inboard side and the outer race on the outboard side.

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