JP2008001237A - Bearing unit for driving wheel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simplify a fitting step to a knuckle member of a bearing unit for a driving wheel including a hub wheel, a bearing, and a constant velocity universal joint, to increase the load capacity of the entire bearing unit, and to improve the life of the bering unit. <P>SOLUTION: An outer peripheral surface 26a of an external member 26 is pressed in an inner peripheral surface of the knuckle member 6. The maximum outer diameter dimension D1 of an out board side constant velocity universal joint 30 is made to be smaller than the minimum inner diameter dimension Dn of the knuckle member 6. At least either one of rolling rows is made into the total rolling element form. <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. 24, 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 by fixing the hub wheel 4 and the wheel bearing 3 to the knuckle member 6 in advance, with 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 swung around the kingpin center from the neutral position, 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 the bearing outer ring 3b to the knuckle member 6 and tightening 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 coupling 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 addition, the main purpose is to improve the life of the bearing unit even under high load conditions.

  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 the inner side of the knuckle member on the vehicle body side. 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, and at least one of the rolling trains has a total rolling element type. 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.

  Moreover, the load capacity of the whole bearing unit can be raised by making any one rolling element row into a total rolling element type.

  According to the present invention, a drive wheel bearing unit including a hub wheel, a bearing, and an outboard side constant velocity universal joint, and a drive wheel integrated with a drive shaft having an outboard side and inboard side constant velocity universal joint. The assembly process of the bearing unit (drive shaft assembly) for the vehicle to the vehicle can be simplified. In addition, the load capacity of the entire bearing unit can be increased, and the life of the bearing unit can be improved.

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

  The drive wheel bearing unit of the first embodiment 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 a wheel 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 inner ring 28 and the hub wheel 10 are positioned in the axial direction 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, and has a double-row inner race 21 and an outer race 22, and rolling elements 23 disposed between the inner race 21 and the outer race 22 facing each other. 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. The outer peripheral surface 26a of the outer member 26 is a cylindrical surface having a uniform diameter as a whole except for the retaining ring groove 26b. Unlike the conventional outer member, the flange for attaching to the knuckle member 6 is not provided. Seals 27 a and 27 b are press-fitted and fixed to the inner peripheral surfaces of both ends in the axial direction of the outer member 26.

As the bearing part 20, as shown in FIG. 5, the total rolling element form which does not use a holder | retainer is employ | adopted. In the case of the total rolling element type, the number of rolling elements that can be incorporated is increased as compared with the case of using a cage, so that the load load of each rolling element can be reduced. Accordingly, the life of the bearing unit can be improved even under high load conditions. The total rolling element type can be used only on the high load side when there is a difference in load load between the inboard side rolling element row and the outboard side rolling element row. Of course, when both rolling element rows have the same load condition, both can be made into a total rolling element type as shown in the figure. Usually, since the moment load on the inboard side becomes large, the rolling element row on the inboard side is made the total rolling element type.

  In the case of the total rolling element type, if the circumferential gap between the rolling elements is too large, the rolling elements may collide violently and generate sound and heat generation. Is smaller than the diameter Db of the rolling element 23 (particularly, when a ball is used as the rolling element 23, the total clearance S is set to about 40% or less of the ball diameter).

The seal 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, and the core metal is attached to the inner peripheral surface of the outer member 26. The outer member 26 is fixed by press-fitting. 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 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 core metal are brought into contact with a slinger having an inverted L-shaped cross section. The seal 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. Both ends of the bearing portion 20 are sealed by the seals 27a and 27b to prevent leakage of grease filled in the inside and intrusion 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 31 are non-separably coupled, 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 pressing 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, the 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. As shown in FIG. 1, 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 contacts the convex portion 6b, and at the same time, the knuckle member 6 The retaining ring groove 6c formed on the inner circumferential surface 6a and the retaining ring groove 26b formed on the outer circumferential surface 26a of the outer member 26 face each other, and the retaining ring 53 accommodated in the retaining ring groove 26b of the outer member 26 is elastic. And is engaged with both the knuckle member 6 and the outer member 26 in the axial direction.

  When a sufficient fixing force can be obtained only by press-fitting, either one or both of the convex portion 6b and the retaining ring 53 can be omitted. 21 shows a case where the convex portion 6b is omitted, and FIG. 22 shows a case where the retaining ring 53 is omitted (as shown in FIG. 22, a retaining ring 29 between the hub wheel 10 and the inner ring 28 is also attached. 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, as shown in FIG. 1, a retaining ring 53 is disposed 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. Is desirable. 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. 21, 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.

  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. 6A illustrates, as an example, a case where the male part 51 is formed on a tooth-shaped surface such as a serration and the female part 51 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. 8, the hub wheel 10 can be prevented from coming off if the flange portion 58 is formed by crimping the outer peripheral portion (shown by a broken line) of the solid shaft end of the stem portion 31 b with a crimping tool 59 after press-fitting. 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. 8 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 shown in FIGS. 10 to 16, the drive wheel bearing unit is formed with an inner race 21 on the outboard side 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. 10 to 16, the hub wheel 10 and the outer joint member 31 are coupled in a non-separable manner, 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.

  10 to 16, the fourth embodiment shown in FIG. 10 is one in which the hub wheel 10 and the outer joint member 31 are plastically coupled by diameter expansion caulking. In the diameter expansion 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.

  In the fifth embodiment shown in FIG. 11, the hub wheel 10 and the outer joint member 31 are non-separated 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.

  In the sixth embodiment shown in FIG. 12, 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.

  10 to 12 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. Thus, they can be non-separated (see FIGS. 13 to 16).

  Among these, the seventh embodiment shown in FIG. 13 is similar to the embodiment shown in FIG. 1 in that the male part 51 and the female part 52 are formed into different shapes, and the male part 51 is press-fitted into the female part 52. The hub wheel 10 and the outer joint member 31 are plastically coupled. In this case, in the hub wheel 10, a male part 51 is formed on the outer peripheral surface of the solid end part 16 on the inboard side, and a female part 52 is formed on the inner peripheral surface of the stem part 31b 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 swaged to form the flange portion 58 by the method shown in FIG. Bond strength can be increased.

  In the eighth embodiment shown in FIG. 14, 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. . In the ninth embodiment shown in FIG. 15, the hub wheel 10 and the outer joint member 31 are plastically coupled by the above-described swing caulking. A cylindrical portion formed on the solid shaft end 16 on the inboard side of the hub wheel 10 is plastically deformed by expanding and caulking to form a flange 17, which is in close contact with the mouth portion 31a. In the tenth embodiment shown in FIG. 16, both members are joined in a non-separated manner by the above 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 FIGS. 2 and 3, both end openings of the bearing portion 20 are sealed with cassette seals 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. 17 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. The column left column (reference numerals 1, 4, 7) in FIG. 17 represents the bearing unit equivalent product shown in FIG. 1, and the column middle column (reference symbols 2, 5, 8) represents the bearing unit equivalent product 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. 9 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.

  Further, as shown in the eleventh embodiment of FIG. 18, by providing a difference between the PCD (P1) of the rolling body row on the outboard side and the PCD (P2) of the rolling body row on the inboard side, Expected to increase rigidity and prolong life. This is because if one PCD is increased, the bearing span (interval between the line of action in the direction of action of the force applied to both race surfaces and the axis) is increased without increasing the axial dimension of the bearing unit. The reason is that the number of rolling elements that can be incorporated and the number of rolling elements that can be incorporated increase. FIG. 18 illustrates the case where the PCD (P2) of the rolling element row on the inboard side is increased, but as shown in FIG. 19, the PCD (P1) of the rolling element row on the outboard side is increased as shown in FIG. May be. The same effect can be obtained even if more rolling elements are incorporated on either side than on the other side. Furthermore, as shown in FIGS. 20A and 20B, the diameter of the rolling element 23 on the inboard side may be different from the diameter of the rolling element 23 on the outboard side.

  FIG. 23 shows a twelfth 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. 23, 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. 23 shows the bearing unit corresponding to FIG. 1 in which the inner member 25 is formed by the hollow hub wheel 10 and the inner ring 28, but the same 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 the bearing unit shown in FIG. 23, the hub ring 10 and the inner rings 28, 28a, and 28b are positioned by the flange 17 by swing caulking. However, as shown in FIG. It can also be done.

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 a simplified diagram of a total rolling element type bearing structure. (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 modification of the bearing unit for drive wheels shown in 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 a side view which illustrates schematically the rolling element which has different PCD. It is a side view which illustrates schematically the rolling element from which a diameter differs. It is principal part sectional drawing which shows the other modification of the bearing unit for drive wheels shown in FIG. It is principal part sectional drawing which shows another modification of the bearing unit for drive wheels shown in FIG. It is sectional drawing of the bearing unit for drive wheels which shows 12th Embodiment of this invention. It is sectional drawing which shows schematic structure around the suspension apparatus of a vehicle.

Explanation of symbols

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 30 Outboard side constant velocity universal joint Dn Minimum inner diameter dimension of knuckle member D1 Outboard side constant velocity universal joint Maximum outer diameter

Claims (1)

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 smaller than the minimum inner diameter of the knuckle member, and at least one of them A bearing unit for a drive wheel, characterized in that the rolling train is made into a total rolling element type.

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