JP2008002581A - 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 joined to the outer joint member 31 of the outboard side constant velocity universal joint 30 by oscillating caulking. A spline 60 is interposed between the inner peripheral surface of the hub ring 10 and the outer peripheral surface of an external joint member 31. The outer peripheral surface 26a of the external member 26 is press-fitted to the inner peripheral surface 6a of the knuckle member 6. 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. <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.

  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 reduce the number of parts, simplify the structure, and reduce the cost.

  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 smaller than the minimum inner diameter of the knuckle member, and the inner peripheral surface of the hub wheel and the outer joint member of the constant velocity universal joint on the outboard side. The present invention is characterized in that swing caulking is performed with a spline interposed between the outer peripheral surface and the hub wheel and the outer joint member. Here, the term “constant velocity universal joint” includes accessories such as boots and boot bands (the same applies to the inboard constant velocity universal joint described below). 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.

  When the outer peripheral surface of the outer member is press-fitted into the inner peripheral surface of the knuckle member when fitting and assembling, the outer member and the knuckle member can be firmly coupled simultaneously with the press-fitting. The bearing gap is set to a negative gap by press fitting. At this time, unlike the prior art, it is not necessary to manage the tightening torque of the nut and perform the preloading operation.

  By making the PCDs of the inboard-side rolling element and the outboard-side rolling element different from each other, the load capacity can be increased in any one of the rolling element rows. Therefore, even when the load acting on the bearing portion is different between the inboard side and the outboard side, the corresponding design can be performed without extremely increasing the size of the bearing unit. The same effect can be achieved by making the diameters of the inboard side rolling element and the outboard side rolling element different from each other, or making the number of inboard side rolling elements and the number of rolling elements on the outboard side different from each other. Can also be obtained. Two or more of these configurations (difference in PCD, difference in rolling element diameter, or difference in the number of rolling elements) may be combined.

  Drives by connecting the constant velocity universal joint on the outboard side and the constant velocity universal joint on the inboard side via an intermediate shaft, and making the maximum outer diameter of the constant velocity universal joints on both sides smaller than the minimum inner diameter of the knuckle member. The wheel bearing unit can be assembled to the vehicle body in an assembly state in which the drive shaft having the outboard side and inboard side constant velocity universal joints and the hub wheel are integrated. This assembly is performed by sequentially inserting the inboard side constant velocity universal joint and the outboard side constant velocity universal joint into the inner periphery of the knuckle member, and then press-fitting the outer member into the inner periphery of the knuckle member.

  As a form of the bearing unit for driving wheels having the above-described configuration, an inner race is formed by forming inner races one by one on the hub wheel and the outer joint member of the constant velocity universal joint on the outboard side. .

  ADVANTAGE OF THE INVENTION According to this invention, the assembly | attachment process to the knuckle member of the bearing unit for drive wheels containing a hub ring, a bearing, and an outboard side constant velocity universal joint can be simplified. In addition, the number of parts can be reduced, the structure can be simplified, and the cost can be reduced.

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

  FIG. 1 shows a drive wheel bearing unit according to a first embodiment of the present invention. This bearing unit 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. 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 an outer joint member 31 described later. In this case, the inner member 25 having the double-row inner race 21 is constituted by the hub wheel 10 and the outer joint member 31.

  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.

  The outboard side seal 27a and the inboard side seal 27b have 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. The member 26 is press-fitted and fixed to the inner peripheral surface. The seal lip of the outboard side seal 27a is in contact with the outer peripheral surface of the hub wheel 10 and the inboard side end surface of the flange portion 11, and the seal lip of the inboard side seal 27b is in contact with the outer peripheral surface of the outer joint member 31 and the radial direction. Each surface is in contact.

  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 31 b of the outer joint member 31 is fitted to the inner peripheral surface of the hub wheel 10. The hub wheel 10 and the outer joint member 31 are coupled 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. By bringing the flange 31b2 into contact with the end face of the hub wheel 10 on the outboard side, the hub wheel 10 is prevented from coming off, and the spline 60 is interposed between the inner peripheral surface of the hub wheel 10 and the outer peripheral surface of the stem portion 31b. As a result, the hub wheel 10 and the outer joint member 31 are prevented from rotating. On the inboard side of the spline 60, a fitting portion 61 is formed by fitting the cylindrical inner peripheral surface of the hub wheel 60 and the cylindrical outer peripheral surface of the stem portion 31b. A radial load acting on is supported.

  When the hub wheel 10 and the outer joint member 31 are 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 hub wheel 10 in the axial direction, so that the distance between the double row inner races 21 is increased. Is maintained at a prescribed size, and a preload (preliminary preload) is applied to the bearing portion 20.

  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, 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. FIG. 3 illustrates a case where the convex portion 6b is 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. Thereby, when the outer member 26 is press-fitted into the knuckle member 6, the sliding distance of the retaining ring 53 with respect to the inner circumferential surface 6 a of the knuckle member can be shortened, so that damage to the inner circumferential surface 6 a of the knuckle member due to the dragging of the retaining ring 53 can be avoided. Can be achieved.

  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 embodiment shown in FIG. As shown in FIG. 3, when the convex portion 6 b is omitted, the inner peripheral surface 6 a of the knuckle member 6 becomes the “minimum inner diameter dimension Dn”.

  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. 2, 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 shown in FIG. 4, it is desirable to form a gap 55 between the outer diameter side region of the seal 27 in the outer peripheral surface 26a of the outer member 26 and the inner peripheral surface 6a of the knuckle member 6 facing the outer peripheral surface 26a. . As shown in the figure, the gap 55 can also be formed by forming a mussel portion 56 on the outer peripheral surface 26 a of the outer member 26, or by forming a mushy portion (not shown) on the inner peripheral surface 6 b of the knuckle member 6. is there. Note that 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, and therefore, as shown by the broken line in FIG. A nuisance part 57 may be formed in the region. Thereby, since the press-fitting area is reduced, the workability at the time of press-fitting can be further increased, and on the other hand, a predetermined preload can be applied to the bearing portion 20 at the time of press-fitting.

  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.

  As shown in FIG. 5, the outboard wall surface 6c1 of the retaining ring groove 6c formed on the inner peripheral surface 6a of the knuckle member 6 can be formed in a tapered surface shape. In this case, if the outer member 26 is pulled out to the outboard side with a predetermined force as indicated by an arrow, the retaining ring 53 is reduced in diameter by the guide of the tapered surface 6c1, so that the drive shaft assembly is separated from the knuckle member 6. This makes it possible to improve the workability of the assembly inspection and replacement work. It is desirable to set the angle θ of the tapered surface 6c1 in the range of 15 ° to 30 °, in order to achieve both the retaining effect when fitting and mounting and the workability during replacement.

  In the first embodiment shown in FIG. 1, the case where the stem portion 31 b is fitted to the inner periphery of the hub wheel 10 is illustrated, but on the contrary, as in the second embodiment shown in FIG. 6, It is also possible to fit the hub wheel 10 to the inner periphery of the hollow stem portion 31b and couple them together by swinging caulking. In this case, the flange 17 is formed by plastically deforming the cylindrical portion formed on the solid shaft end 16 on the inboard side of the hub wheel 10 by expanding the diameter, and the flange 17 is brought into close contact with the mouth portion 31a. The hub wheel 10 and the outer joint member 31 are prevented from coming off. A spline 60 is formed between the inner peripheral surface of the stem portion 31b and the outer peripheral surface of the hub wheel 10, and a fitting portion 61 in which the cylindrical surfaces are fitted to each other is formed on the outboard side. The end surface 31b3 on the outboard side of the stem portion 31b is brought into contact with the shoulder surface of the hub wheel 10 so as to be coupled, so that the interval between the double row inner races 21 is maintained at a predetermined size, and the bearing portion 20 is preloaded (preliminary preload). ) Is given.

  In the bearing unit described above, the bearing portion 20 in which the rolling element 23 is held by the cage 24 is illustrated. However, as shown in FIG. 7, a total rolling element type that does not use a cage can also be 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. 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).

  Also in the bearing type using the cage 24, as shown in FIG. 8, there is 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. As a result, an effect of increasing rigidity and extending the service life can be expected. 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. 8 illustrates the case where the PCD (P2) of the rolling element row on the inboard side is increased, but the PCD (P1) of the rolling body row on the outboard side is increased as shown in FIG. May be. Further, by making the inboard side retainer 24 and the outboard side retainer 24 different from each other, the same effect can be obtained even if more rolling elements are incorporated in the retainer 24 on either side. It is done. Furthermore, as shown in FIGS. 10A and 10B, the same effect can be obtained even when the diameter of the rolling element 23 on the inboard side is different from the diameter of the rolling element 23 on the outboard side.

  FIG. 11 shows a third embodiment of the drive wheel bearing unit.

  In this bearing unit, the outer member 26 includes a pair of bearing outer rings 261 and 262 and a ring-shaped spacer 263 disposed between the bearing outer rings 261 and 262. Outer races 22 are formed on the inner peripheral surfaces of both bearing outer rings 261 and 262, respectively. A double row inner race 21 is directly formed on the outer peripheral surface of the hub wheel 10. In this case, the hub wheel 10 constitutes an inner member 25 having a double row inner race. In the drawing, the end surface on the inboard side of the hub wheel 10 is brought into contact with the shoulder surface 38 of the outer joint member 31, but a gap may be interposed therebetween.

  Out of the seals 27a and 27b that seal the opening portions at both ends of the bearing portion 20, the seal 27a on the outboard side is coated with an elastic material such as rubber to form a plurality of (for example, two) seal lips. It consists of a core bar 271 and a slinger 272 that comes into contact with the seal lip. The metal core 271 is press-fitted and fixed to the outer peripheral surface of the hub wheel 10, and the slinger 272 is press-fitted and fixed to the inner peripheral surface of the bearing outer ring 262 on the outboard side. The end on the outboard side of the slinger 272 is adjacent to the inboard side end surface of the flange 11 to form a labyrinth seal.

  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 press-fitting the metal core into the inner peripheral surface of the inboard-side bearing outer ring 261 and press-fitting the slinger into the outer peripheral surface of the hub wheel 10.

  The outer peripheral surfaces of the bearing outer rings 261 and 262 and the spacer 263 are all cylindrical surfaces. Each of the bearing outer rings 261, 262 has a cylindrical outer peripheral surface and is press-fitted into the inner peripheral surface 6a of the knuckle member 6. The outer diameter of the spacer 263 is the outer diameter of the bearing outer rings 261, 262. There is a slight gap between the inner peripheral surface of the knuckle member 6 and slightly smaller than the size. The spacer 263 is divided into two parts in the circumferential direction as shown in FIG.

  The bearing outer ring 262 on the outboard side is positioned by a retaining ring 53. As the retaining ring 53, as shown in FIG. 12, a C-type having an operation portion 53a extending to the outer diameter side at both ends in the circumferential direction can be used. The retaining ring 53 is fitted into a retaining ring groove 6 c formed on the inner peripheral surface of the knuckle member 6, and the operation portion 53 a is accommodated in the axial notch 6 d formed on the knuckle member 6, so that the retaining ring 53 is supported by the bearing outer ring. The outer member is positioned by engaging with the end face on the outboard side of 262.

  The bearing unit is assembled in the following procedure.

  First, as shown in FIG. 14, the metal core 271 of the seal 27 a on the outboard side is press-fitted and fixed to the outer periphery of the hub wheel 10.

  Next, as shown in FIG. 15, the rolling elements 23 are assembled on the outer periphery of the hub wheel 10 and accommodated in the inner race 21. At this time, the rolling element 23 is incorporated in the outer periphery of the hub wheel 10 in a state of being accommodated in the pocket of the cage 24 in advance. Next, the bearing outer ring 262 on the outboard side is inserted into the outer periphery of the hub wheel 10. At this time, the slinger 272 is press-fitted into the inner peripheral surface of the bearing outer ring 262 in advance. When the bearing outer ring 262 is pushed to the outboard side, the seal lip formed on the cored bar 271 contacts the inner peripheral surface of the slinger 272, and the seal 27a is formed. Further, the rolling element 23 is accommodated in the outer race 22 of the bearing outer ring 262.

  Next, as shown in FIG. 16, the bearing outer ring 261 on the inboard side is inserted into the outer periphery of the hub ring 10. At this time, the bearing outer ring 261 is positioned on the outboard side from the specified position by contacting the bearing outer ring 262 on the outboard side or the like, so that the inboard side end portion of the bearing outer ring 261 and the hub wheel 10 are interposed. Since a gap δ larger than the ball diameter D is formed, the rolling element 23 is inserted into the space between the bearing outer ring 261 and the hub ring 10 from this gap δ. When the prescribed number of rolling elements 23 has been inserted, the retainer 24 is pushed through the opening on the inboard side to accommodate the rolling elements 23 in the pockets, and the rolling elements 23 are held at equal intervals in the circumferential direction.

  Next, as shown in FIG. 17, a gap is formed between the bearing outer rings 261, 262, and the split spacer 263 is inserted so that the hub ring 10 is sandwiched in the gap. As a result, the bearing outer ring 261 on the inboard side is disposed at the specified position, and the rolling element 23 on the inboard side is accommodated in the inner race 21 and the outer race 22 with a predetermined contact angle.

  Thereafter, as shown in FIG. 18, a cassette seal is press-fitted into the opening between the inboard-side bearing outer ring 261 and the hub wheel 10 to form a seal 27 b.

  After the above assembly is completed, the stem portion 31b of the outer joint member 31 is inserted into the inner periphery of the hub wheel 10, and the shaft end is subjected to swing caulking so that the outer joint member 31 and the hub wheel 10 are not separated. Join. A spline 60 is interposed between the inner peripheral surface of the hub wheel 10 and the outer peripheral surface of the stem portion 31b, and a fitting portion 61 is provided on the inboard side. Thereafter, the inboard side constant velocity universal joint 40, the intermediate shaft 2, and the outboard side constant velocity universal joint 30 are inserted in this order into the inner periphery of the knuckle member 6, and finally the outer ring member 53 is expanded while the diameter of the retaining ring 53 is increased. 26 is press-fitted into the inner periphery of the knuckle member 6, and the bearing outer ring 261 on the inboard side is brought into contact with the convex portion 6b. Thereafter, the retaining ring 53 is elastically reduced in diameter and engaged with the end face of the bearing outer ring 262 to complete the assembly of the drive shaft assembly.

  With the above configuration, since the insertable spacer 263 is disposed between the pair of bearing outer rings 261, 262, even when the inner race 21 is formed directly on the hub wheel 10, double rows The rolling element 23 can be incorporated in the space between the outer member 26 and the hub wheel 10. Therefore, the inner ring 3a shown in FIG. 20 is not necessary, and the cost can be reduced by reducing the number of parts.

  In this embodiment, in addition to using a retaining ring 53 that engages with the end face of the bearing outer ring 262 as shown in FIG. 11, the outer peripheral face of the bearing outer ring 262 on the outboard side as shown in FIG. A retaining ring 53 interposed between the inner peripheral surface 6a of the knuckle member 6 can also be used. If there is no particular problem in assemblability, the seal 27a on the outboard side has a seal lip at the inner diameter end of the cored bar as in the seal 27a shown in FIG. It is also possible to use a type that is press-fitted into the inner peripheral surface of 26.

  FIG. 19 shows a fourth embodiment of the present invention. 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.

It is sectional drawing of the bearing unit for drive wheels concerning 1st Embodiment. FIG. 6 is a cross-sectional view of a drive shaft assembly. It is sectional drawing of the bearing unit for drive wheels. It is sectional drawing which expands and shows a part of bearing unit for drive wheels. 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 expands and shows the press fit part of an outward member and a knuckle member. It is sectional drawing of the bearing unit for drive wheels concerning 2nd Embodiment. It is a front view showing a total rolling element type bearing structure. It is sectional drawing of the bearing unit for drive wheels which gave the difference to the rolling element PCD. 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 sectional drawing of the bearing unit for drive wheels concerning 3rd Embodiment. It is sectional drawing of a retaining ring. It is sectional drawing of a spacer. It is sectional drawing which shows the assembly process of the bearing unit for drive wheels. It is sectional drawing which shows the assembly process of the bearing unit for drive wheels. It is sectional drawing which shows the assembly process of the bearing unit for drive wheels. It is sectional drawing which shows the assembly process of the bearing unit for drive wheels. It is sectional drawing which shows the assembly process of the bearing unit for drive wheels. It is sectional drawing of the bearing unit for drive wheels concerning 4th Embodiment. It is sectional drawing which shows schematic structure around the suspension apparatus of a vehicle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Drive shaft 2 Intermediate shaft 6 Knuckle member 6a Inner peripheral surface 6b Protruding part 6c Retaining ring groove 6c1 Tapered surface 10 Hub wheel 11 Flange 20 Bearing part 21 Inner race 22 Outer race 23 Rolling body 24 Cage 25 Inner member 26 Outer member 26a Outer peripheral surface 27a Seal 27b Seal 28 Inner ring 30 Outboard side constant velocity universal joint 31 Outer joint member 31a Mouse part 31b Stem part 32 Inner joint member 33 Torque transmission ball 34 Cage 36 Boot band 37 Boot 38 Shoulder surface 40 Inboard side etc. Fast universal joint 53 Retaining ring 56 Nusumi part 57 Nusumi part 70 Brake rotor 72 Pilot part 80 Wheel Dn Minimum inner diameter dimension of the knuckle member D1 Maximum outer diameter dimension of the outboard side constant velocity universal joint D2 Maximum of the inboard side constant velocity universal joint Outer diameter O Axial center line

Claims (5)

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. A drive characterized by coupling a hub wheel and an outer joint member by swinging and caulking with a spline interposed between the outer surface of the outer joint member of the constant velocity universal joint on the outboard side Wheel bearing unit.   The drive wheel bearing unit according to claim 1, wherein the outer peripheral surface of the outer member is press-fitted into the inner peripheral surface of the knuckle member.   3. The drive wheel bearing unit according to claim 1, wherein the inboard side rolling element and the outboard side rolling element have different PCDs.   The outboard side constant velocity universal joint and the inboard side constant velocity universal joint are connected via an intermediate shaft, and the maximum outer diameter dimension of the constant velocity universal joint on both sides is made smaller than the minimum inner diameter dimension of the knuckle member. 3. A drive wheel bearing unit according to any one of 3 above.   The drive wheel bearing unit according to any one of claims 1 to 4, wherein an inner race is formed by forming an inner race on each of the outer joint members of the hub wheel and the outboard side constant velocity universal joint.

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