JP6253906B2 - Wheel bearing device - Google Patents

Description

  The present invention relates to a wheel bearing device that rotatably supports driving wheels (front wheels of FF vehicles, rear wheels of FR vehicles, all wheels of 4WD vehicles), for example, with respect to a suspension device of an automobile.

  For example, as shown in FIG. 28, a conventional wheel bearing device includes a wheel bearing 106 including a hub wheel 101, an inner ring 102, double-row rolling elements 103 and 104, and an outer ring 105, and a constant velocity universal joint 107. The part is composed.

  The hub wheel 101 has an inner raceway surface 108 on the outboard side formed on the outer peripheral surface thereof, and a wheel mounting flange 109 for mounting a wheel (not shown). Hub bolts 110 for fixing the wheel disc are implanted at equal intervals in the circumferential direction of the wheel mounting flange 109. An inner ring 102 is fitted into a small diameter step portion 111 formed on the inboard side outer peripheral surface of the hub wheel 101, and an inner raceway surface 112 on the inboard side is formed on the outer peripheral surface of the inner ring 102. A female spline 113 for connecting the constant velocity universal joint 107 so as to transmit torque is formed on the inner peripheral surface of the shaft hole of the hub wheel 101.

  The inner ring 102 is press-fitted with an appropriate tightening margin to prevent creep. The inner raceway 108 on the outboard side formed on the outer peripheral surface of the hub wheel 101 and the inner raceway surface 112 on the inboard side formed on the outer peripheral surface of the inner ring 102 constitute a double row inner raceway surface. . The inner ring 102 is press-fitted into the small-diameter step portion 111 of the hub wheel 101, the end portion of the small-diameter step portion 111 is crimped to the outside, and the inner ring 102 is prevented from coming off with the crimping portion 114 and integrated with the hub wheel 101, A preload is applied to the wheel bearing 106.

  The outer ring 105 is formed with double-row outer raceways 115 and 116 facing the inner raceways 108 and 112 of the hub ring 101 and the inner ring 102 on the inner circumference, and is attached to the vehicle body (not shown) on the outer circumference. A vehicle body mounting flange 117 is provided. The vehicle body mounting flange 117 is fixed to a knuckle extending from a vehicle suspension system (not shown) with a bolt or the like using the mounting hole 118.

  The wheel bearing 106 has a double-row angular contact ball bearing structure, and has inner raceway surfaces 108 and 112 formed on the outer peripheral surfaces of the hub wheel 101 and the inner ring 102 and an outer raceway surface 115 formed on the inner peripheral surface of the outer ring 105. The rolling elements 103 and 104 are interposed between the rolling elements 103 and 104, and the rolling elements 103 and 104 in each row are supported by the cages 119 and 120 at equal intervals in the circumferential direction.

  A pair of seals 121 and 122 that seal the annular space between the outer ring 105, the hub ring 101, and the inner ring 102 are fitted into the inner diameters of both ends of the outer ring 105 and filled in the openings at both ends of the wheel bearing 106. It prevents leakage of lubricants such as grease and intrusion of water and foreign matters from the outside.

  A wheel bearing device is configured by connecting the outer joint member 123 of the constant velocity universal joint 107 to the hub wheel 101. The outer joint member 123 includes a cup-shaped mouth portion 124 that houses an inner joint member, an inner part (not shown) made of a ball and a cage, and a stem portion 125 that integrally extends from the mouth portion 124 in the axial direction. Has been. A male spline 126 is formed on the outer peripheral surface of the stem portion 125 so as to be connected to the hub wheel 101 so that torque can be transmitted.

  The stem portion 125 of the outer joint member 123 is press-fitted into the shaft hole of the hub wheel 101, the nut 127 is screwed into the male screw portion 129 formed at the end portion of the stem portion 125, and the nut 127 is connected to the end surface of the hub wheel 101. The constant velocity universal joint 107 is fixed to the hub wheel 101 by tightening in a state of being locked to the hub wheel 101. The shoulder 128 of the outer joint member 123 is brought into contact with the caulking portion 114 of the hub wheel 101 with the tightening force (axial force) of the nut 127. In this way, torque can be transmitted from the constant velocity universal joint 107 to the wheel bearing 106 by fitting the male spline 126 of the stem portion 125 and the female spline 113 of the hub wheel 101.

  In this wheel bearing device, the caulking portion 114 of the hub wheel 101 and the shoulder portion 128 of the outer joint member 123 facing the caulking portion 114 are in contact with each other with the tightening force (axial force) of the nut 127. It is in. From this, when the vehicle is started and a rotational torque is applied from the constant velocity universal joint 107 to the stationary wheel bearing 106, the outer joint member 123 passes through the male and female splines 113 and 126 to the hub wheel 101. Although rotational torque is to be transmitted, a sudden slip occurs between the caulking portion 114 of the hub wheel 101 and the shoulder portion 128 of the outer joint member 123 due to torsion of the outer joint member 123. Due to this sudden slip, a stick-slip sound commonly referred to as a cuckling sound may occur.

  As a means for preventing this stick-slip noise, the frictional resistance at the contact surface between the caulking portion 114 of the hub wheel 101 and the shoulder portion 128 of the outer joint member 123 is increased so that a sudden slip does not occur. Means have been taken (see, for example, Patent Document 1). In Patent Document 1, as a means for increasing the frictional resistance, a structure in which a radial, elliptical or cross-hatched uneven portion is formed on the contact surface of the shoulder 128 of the outer joint member 123, A structure in which a rubber or resin spacer is provided on the contact surface of the shoulder 128 is disclosed.

  Further, as another means for preventing stick-slip noise, frictional resistance at the contact surface between the caulking portion 114 of the hub wheel 101 and the shoulder portion 128 of the outer joint member 123 is prevented so that a sudden slip does not occur. A means for reducing the above is taken (for example, see Patent Document 2). This Patent Document 2 discloses a structure in which a concave groove is formed on the contact surface of the caulking portion 114 of the hub wheel 101 and grease is filled in the concave groove.

JP 2003-97588 A JP 2003-136908 A

  By the way, in the conventional wheel bearing device disclosed in Patent Documents 1 and 2, the frictional resistance at the contact surface between the caulking portion 114 of the hub wheel 101 and the shoulder portion 128 of the outer joint member 123 is increased, On the contrary, by reducing the frictional resistance at the contact surface between the caulking portion 114 of the hub wheel 101 and the shoulder portion 128 of the outer joint member 123, it is possible to prevent a sudden relative slip from occurring. I try to prevent noise.

  However, as means for increasing the frictional resistance, an uneven portion or a spacer must be provided on the contact surface of the shoulder portion 128 of the outer joint member 123. Further, as a means for reducing the frictional resistance, a concave groove must be formed on the contact surface of the caulking portion 114 of the hub wheel 101. As described above, as a process of changing the frictional resistance on the contact surface, it is necessary to form a concave and convex portion, a concave groove, or a spacer as a separate member, which increases the cost of the wheel bearing device. There was a problem of inviting.

  Therefore, the present invention has been proposed in view of the above-mentioned problems, and the object of the present invention is to eliminate the need to change the frictional resistance on the contact surface and prevent stick-slip noise by simple means. Another object of the present invention is to provide a wheel bearing device that can be used.

As technical means for achieving the above-mentioned object, the present invention comprises an outer member having a double-row outer raceway surface formed on the inner periphery, and a double-row inner raceway surface facing the outer raceway surface on the outer periphery. A wheel bearing comprising: an inner member comprising a hub ring and an inner ring; and a double row rolling element interposed between the outer raceway surface of the outer member and the inner raceway surface of the inner member. The constant velocity universal joint is coupled to the wheel bearing by a screw tightening structure by fitting the stem portion of the outer joint member of the constant velocity universal joint to the inner diameter of the hub ring, and the outer joint member is joined to the end of the inner member. In the wheel bearing device in which the shoulder portion is in contact, the plurality of convex portions formed in one of the hub portion and the stem portion of the outer joint member and extending in the axial direction are formed only on the circumferential side wall portion of the convex portion. the other of the plurality of recesses having interference is formed for, by tightening screws Pressed with the cutting of the recessed surface by circumferential side wall portion of the protrusion in the axial force less pulling force live, by transferring the circumferential side wall of the convex portion to the other of the protrusion and the recess fitting contact regions throughout the close contact of the recess constitutes a recess-projection fitting structure which have a gap with respect to the radial tip of the convex portion, and the axial force generated by the axial force and fitting force generated by the clamping screw The difference is set to 32 kN or less.

  In the present invention, a plurality of convex portions extending in the axial direction are formed on one of the hub portion and the stem portion of the outer joint member, and a concave portion having a tightening margin with respect to the convex portion is formed in advance on the other side. . By pressing any one of the hub wheel and the stem portion of the outer joint member into the other, an uneven fitting structure in which the entire fitting contact portion between the convex portion and the concave portion is in close contact is configured.

  At this time, the concave portion forming surface is slightly cut by the convex portion, and the convex portion is formed on the other concave portion forming surface while accompanying slight plastic deformation and elastic deformation of the concave portion forming surface by the convex portion. Transcript. At this time, the convex portion bites into the concave-part forming surface on the other side, so that the inner diameter of the hub wheel is slightly expanded, and relative movement in the axial direction of the convex portion is allowed. When the axial relative movement of the convex portion stops, the inner diameter of the hub wheel is reduced to return to the original diameter. Thereby, it can closely_contact | adhere in the fitting contact site | part whole area | region of a convex part and a recessed part, and an outer joint member and a hub ring can be combined firmly.

  Here, since the recessed part which has a fastening allowance with respect to a convex part is formed previously, an outer joint member can be press-fit with respect to a hub ring below the axial force which generate | occur | produces by screw fastening. As a result, it is not necessary to prepare a special jig separately when press-fitting the stem portion of the outer joint member into the hub wheel, and the constant velocity universal joint can be simplified by screw tightening using the components constituting the wheel bearing device. Can be coupled to a wheel bearing.

  In the present invention, the difference between the axial force generated by screw tightening and the axial force generated by pressure input is set to 32 kN or less. Thus, by setting the difference between the axial force generated by screw tightening and the axial force generated by pressure input to 32 kN or less, the difference between the axial force generated by screw tightening and the axial force generated by pressure input, that is, The axial force generated on the contact surface between the end portion of the inner member and the shoulder portion of the outer joint member is 32 kN or less. As a result, the surface pressure at the contact surface between the end portion of the inner member and the shoulder portion of the outer joint member can be reduced, and rotational torque is applied to the wheel bearing from the constant velocity universal joint when the vehicle starts. In this case, it is possible to avoid a sudden slip on the contact surface and to prevent the occurrence of a stick-slip sound.

  The screw tightening structure according to the present invention includes a female screw portion formed at the shaft end of the stem portion of the outer joint member, and a male screw portion that is engaged with the female screw portion and locked to the hub wheel. Is possible. In this structure, the constant velocity universal joint is fixed to the hub ring by screwing the male screw part into the female screw part of the stem part and tightening the male screw part in a state where the male screw part is locked to the hub ring.

  In the present invention, it is desirable that the convex portion is provided in the stem portion of the outer joint member and the concave portion is provided in the hub wheel. By adopting such a structure, it is possible to easily configure an uneven fitting structure in which the entire fitting contact portion between the convex portion and the concave portion is in close contact by press-fitting the stem portion of the outer joint member into the hub wheel. .

  In the present invention, in the structure in which the convex portion is provided in the stem portion of the outer joint member and the concave portion is provided in the hub ring, the axial direction from the shoulder portion to the convex portion of the outer joint member with which the end portion of the inner member abuts. It is desirable that a value obtained by dividing the length by the maximum outer diameter of the stem portion is 0.3 or less, and a value obtained by dividing the axial length of the stem portion by the maximum outer diameter of the stem portion is 1.3 or less. In this way, if the axial length with respect to the maximum outer diameter of the stem portion is set, when rotational torque is applied from the constant velocity universal joint to the wheel bearing when the vehicle starts, effective fitting in the concave-convex fitting structure It is possible to reduce the amount of twist of the outer joint member while ensuring the length. As a result, it is possible to reliably avoid the occurrence of a sudden slip at the contact surface between the end portion of the inner member and the shoulder portion of the outer joint member, and to prevent the occurrence of stick-slip noise.

  According to the present invention, a plurality of convex portions formed in any one of the hub wheel and the stem portion of the outer joint member and extending in the axial direction are formed into a plurality of concave portions having an allowance for the convex portion. By press-fitting into the other side and transferring the shape of the convex part to the other side, a concavity and convexity fitting structure is formed in which the whole contact area of the convex part and the concave part is in close contact with each other. Since the concave portion having the above is formed in advance, the outer joint member can be press-fitted into the hub wheel with the axial force generated by screw tightening or less. As a result, the difference between the axial force generated by screw tightening and the axial force generated by pressure input is 32 kN or less, so that the surface at the contact surface between the end of the inner member and the shoulder of the outer joint member The pressure can be reduced, and when a rotational torque is applied from the constant velocity universal joint to the wheel bearing when starting the vehicle, it is possible to avoid a sudden slip on the contact surface and to generate a stick slip noise. Can be prevented in advance.

In embodiment of this invention, it is sectional drawing which shows the whole structure of the wheel bearing apparatus. It is sectional drawing which shows the state before attaching a constant velocity universal joint to the wheel bearing of FIG. It is sectional drawing which shows the state in the middle of assembling a constant velocity universal joint to the wheel bearing of FIG. In the embodiment in which a concave portion having a tightening margin is formed only on the circumferential side wall portion of the convex portion, (A) is a main portion showing a state before the stem portion of the outer joint member is press-fitted into the hub wheel of the wheel bearing. An expanded sectional view and (B) are sectional views which follow an AA line of (A). In the embodiment in which a concave portion having a tightening margin is formed only on the circumferential side wall portion of the convex portion, (A) is a main portion showing a state in which the stem portion of the outer joint member is press-fitted into the hub wheel of the wheel bearing. An expanded sectional view and (B) are sectional views which follow a BB line of (A). In the embodiment in which a concave portion having a tightening margin is formed only on the circumferential side wall portion of the convex portion, (A) is a main portion showing a state after the stem portion of the outer joint member is press-fitted into the hub wheel of the wheel bearing. An expanded sectional view and (B) are sectional views which follow a CC line of (A). It is a table | surface which shows the test result based on the axial force measurement which this applicant performed. It is a front view of the partial cross section which shows the volt | bolt which embedded the strain gauge. In the embodiment in which a concave portion having a tightening margin is formed with respect to the circumferential side wall portion and the radial front end portion of the convex portion, (A) is a state before the stem portion of the outer joint member is press-fitted into the hub wheel of the wheel bearing. The principal part expanded sectional view which shows this, (B) is sectional drawing which follows the DD line | wire of (A). In the embodiment in which a concave portion having a tightening margin is formed with respect to the circumferential side wall portion and the radial front end portion of the convex portion, (A) is a state in the middle of press-fitting the stem portion of the outer joint member into the hub wheel of the wheel bearing The principal part expanded sectional view which shows this, (B) is sectional drawing which follows the EE line | wire of (A). In the embodiment in which a concave portion having a tightening margin is formed with respect to the circumferential side wall portion and the radial front end portion of the convex portion, (A) is a state after the stem portion of the outer joint member is press-fitted into the hub wheel of the wheel bearing The principal part expanded sectional view which shows this, (B) is sectional drawing which follows the FF line | wire of (A). It is sectional drawing which shows the form which mounted | wore with the cylindrical seal | sticker in the stem part of an outer joint member in other embodiment of this invention. It is a principal part expanded sectional view of FIG. It is sectional drawing which shows the state in the middle of assembling a constant velocity universal joint to the wheel bearing of FIG. It is a principal part expanded sectional view of FIG. It is sectional drawing which shows the form which interposed the cylindrical seal between the hub ring and the volt | bolt in other embodiment of this invention. It is a principal part expanded sectional view of FIG. In other embodiment of this invention, it is sectional drawing which shows the form which interposed the cylindrical seal with a flange between the hub ring and the volt | bolt. It is a principal part expanded sectional view of FIG. In other embodiment of this invention, it is sectional drawing which shows the form which attached the seal | sticker with a lip to the inner ring | wheel of the wheel bearing. It is a principal part expanded sectional view of FIG. It is sectional drawing which shows the form which mounted | wore the inner ring | wheel of the wheel bearing with the labyrinth seal in other embodiment of this invention. It is a principal part expanded sectional view of FIG. In other embodiment of this invention, it is sectional drawing which shows the form which mounted | wore the shoulder part of the outer joint member with the seal | sticker with a lip | rip. It is a principal part expanded sectional view of FIG. In other embodiment of this invention, it is sectional drawing which shows the form which mounted | wore the shoulder part of the outer joint member with the labyrinth seal. It is a principal part expanded sectional view of FIG. It is sectional drawing which shows the whole structure of the conventional wheel bearing apparatus.

  An embodiment of a wheel bearing device according to the present invention will be described in detail below. A wheel bearing device shown in FIG. 1 includes a hub wheel 1 and an inner ring 2 that are inner members, double-row rolling elements 3 and 4, and a wheel bearing 6 that includes an outer ring 5 that is an outer member, and a constant velocity universal joint 7. And the main part is composed. In the following description, the side closer to the outer side of the vehicle body is referred to as the outboard side (left side in the drawing) and the side closer to the center is referred to as the inboard side (right side in the drawing).

  The hub wheel 1 has an inner raceway surface 8 on the outboard side formed on the outer peripheral surface thereof, and includes a wheel mounting flange 9 for mounting a wheel (not shown). Hub bolts 10 for fixing the wheel disc are implanted at equal intervals in the circumferential direction of the wheel mounting flange 9. An inner ring 2 is fitted to a small-diameter step portion 11 formed on the inboard side outer peripheral surface of the hub wheel 1, and an inner raceway surface 12 on the inboard side is formed on the outer peripheral surface of the inner ring 2.

  The inner ring 2 is press-fitted with an appropriate tightening margin to prevent creep. An outboard side inner raceway surface 8 formed on the outer peripheral surface of the hub wheel 1 and an inboard side inner raceway surface 12 formed on the outer peripheral surface of the inner ring 2 constitute a double row raceway surface. The inner ring 2 is press-fitted into the small-diameter step portion 11 of the hub wheel 1, and the end portion of the small-diameter step portion 11 is crimped outward by swing caulking. 1 and preload is applied to the wheel bearing 6.

  The outer ring 5 is formed with double-row outer raceway surfaces 14 and 15 facing the inner raceway surfaces 8 and 12 of the hub wheel 1 and the inner ring 2 on the inner circumference surface, and is attached to a vehicle body (not shown) on the outer circumference surface. A vehicle body mounting flange 16 is provided. The vehicle body mounting flange 16 is fixed to a knuckle extending from a vehicle suspension system (not shown) with a bolt or the like using the mounting hole 17.

  The wheel bearing 6 has a double-row angular ball bearing structure, and has inner raceway surfaces 8 and 12 formed on the outer peripheral surfaces of the hub wheel 1 and the inner ring 2 and an outer raceway surface 14 formed on the inner peripheral surface of the outer ring 5. The rolling elements 3 and 4 are interposed between the rolling elements 3 and 4, and the rolling elements 3 and 4 in each row are supported by the cages 18 and 19 at equal intervals in the circumferential direction. Since the wheel bearing 6 has a structure in which the inner ring 2 is prevented from coming off by the caulking portion 13 and is integrated with the hub wheel 1, it can be separated from the outer joint member 20 of the constant velocity universal joint 7. It has become.

  A pair of seals 21 and 22 that seal the annular space between the outer ring 5, the hub wheel 1, and the inner ring 2 are provided at both ends of the wheel bearing 6. The seals 21 and 22 are fitted to inner diameters at both ends of the outer ring 5 to prevent leakage of a lubricant such as grease filled therein and intrusion of water and foreign matters from the outside. The seal 21 is composed of a cored bar and an elastic member, and the tip of the lip of the elastic member is in sliding contact with the outer peripheral surface of the hub wheel 1. The seal 22 is a so-called pack seal type, which is composed of two L-shaped metal cores and an elastic member. The elastic member is attached to one metal core, and the elastic member is attached to the outer peripheral surface of the other metal core attached to the outer periphery of the inner ring. The tip of the lip comes into sliding contact.

  The constant velocity universal joint 7 is a fixed type constant velocity universal joint that is provided at one end of a shaft 23 constituting a drive shaft and allows only angular displacement between two axes of a drive side and a driven side. The constant velocity universal joint 7 includes an outer joint member 20 in which a track groove 24 is formed on the inner peripheral surface, and an inner joint member in which a track groove 25 facing the track groove 24 of the outer joint member 20 is formed on the outer peripheral surface. 26, a ball 27 incorporated between the track groove 24 of the outer joint member 20 and the track groove 25 of the inner joint member 26, and between the inner peripheral surface of the outer joint member 20 and the outer peripheral surface of the inner joint member 26. And a cage 28 for holding the ball 27.

  The outer joint member 20 includes a cup-shaped mouth portion 29 that accommodates an inner joint member 26, a ball 27, and a cage 28, and a stem portion 30 that extends integrally from the mouth portion 29 in the axial direction. ing. The inner joint member 26 is coupled to the shaft 23 so that the shaft end of the shaft 23 is press-fitted and torque can be transmitted by spline fitting.

  Between the outer joint member 20 of the constant velocity universal joint 7 and the shaft 23, a resin bellows shape for preventing leakage of a lubricant such as grease sealed in the joint and preventing foreign matter from entering from the outside of the joint. The boot 31 is attached and the opening of the outer joint member 20 is closed with the boot 31. The boot 31 includes a large-diameter end portion fastened and fixed to the outer peripheral surface of the outer joint member 20 by a boot band, a small-diameter end portion fastened and fixed to the outer peripheral surface of the shaft 23 by a boot band, a large-diameter end portion and a small-diameter portion. It is composed of a flexible bellows portion connected to the end portion and reduced in diameter from the large diameter end portion toward the small diameter end portion.

  As shown in FIG. 2, the wheel bearing device has a base portion 32 of the stem portion 30 of the outer joint member 20 having a cylindrical shape, and a plurality of protrusions extending in the axial direction from the root portion 32 to the outer peripheral surface on the outboard side. A male spline composed of the portion 33 is formed. On the other hand, the front end portion 35 of the shaft hole 34 of the hub wheel 1 is formed in a cylindrical shape, and the circumferential side wall 71 of the above-described convex portion 33 [see FIG. A plurality of recesses 36 having a tightening allowance n for only reference]. The concave portion 36 is set smaller than the convex portion 33 so as to have a tightening allowance n only with respect to the circumferential side wall portion 71 of the convex portion 33. Thus, in order to set the concave portion 36 smaller than the convex portion 33, the circumferential dimension of the concave portion 36 may be made smaller than the convex portion 33. Moreover, since the site | part except the circumferential direction side wall part 71 of the convex part 33, ie, the radial direction front-end | tip part 72 of the convex part 33 does not have the interference with the recessed part 36, the radial direction dimension of the recessed part 36 is made into the convex part 33. By setting it larger than this, the concave portion 36 has a gap p with respect to the radial front end portion 72 of the convex portion 33.

  In this wheel bearing device, as shown in FIGS. 3 and 5 (A) and 5 (B), the stem portion 30 of the outer joint member 20 is press-fitted into the shaft hole 34 of the hub wheel 1, and the concave portion forming surface on the mating side is used. A concave portion 37 is formed by transferring the shape of the circumferential side wall portion 71 of the convex portion 33 to the shaft hole 34 of a certain hub wheel 1 (see FIGS. 6A and 6B). In addition, since the radial front end portion 72 of the convex portion 33 does not have an interference with the concave portion 36, the shape of the radial front end portion 72 of the convex portion 33 is not transferred to the concave portion 36. When the stem portion 30 is press-fitted into the shaft hole 34, the recess forming surface is cut slightly by the circumferential side wall portion 71 of the projection 33, and the recess forming surface by the circumferential side wall portion 71 of the projection 33 is extremely small. The shape of the circumferential side wall portion 71 of the convex portion 33 is transferred to the concave portion forming surface while accompanying plastic deformation and elastic deformation. At this time, the convex portion 33 bites into the concave portion forming surface, so that the inner diameter of the hub wheel 1 is slightly increased, and the relative movement in the axial direction of the convex portion 33 is allowed. When the axial relative movement of the convex portion 33 stops, the inner diameter of the hub wheel 1 is reduced to return to the original diameter.

  In this way, the concave / convex fitting structure M is formed in which the convex portion 33 and the concave portion 37 are in close contact with each other in the fitting contact region X. Thereby, the outer joint member 20 and the hub wheel 1 can be firmly coupled and integrated. In this concave / convex fitting structure M, a gap that generates backlash in the radial direction and the circumferential direction of the fitting portion of the stem portion 30 and the hub wheel 1 is not formed due to low-cost and highly reliable coupling. X contributes to torque transmission and enables stable torque transmission, which can prevent unpleasant rattling noise over a long period of time. As described above, since the fitting contact region X is in close contact with each other, the strength of the torque transmission region is improved, so that the wheel bearing device can be reduced in weight and size.

  Here, the surface hardness of the convex portion 33 is made larger than the surface hardness of the concave portion 36. In that case, the difference between the surface hardness of the convex portion 33 and the surface hardness of the concave portion 36 is set to 20 or more in HRC. Thus, when the stem portion 30 of the outer joint member 20 is press-fitted into the shaft hole 34 of the hub wheel 1, the concave portion forming surface is slightly cut by the circumferential side wall portion 71 of the convex portion 33, and the peripheral portion of the convex portion 33 is cut. The shape of the circumferential side wall portion 71 of the convex portion 33 can be easily transferred to the concave portion forming surface on the other side, accompanied by a slight plastic deformation or elastic deformation of the concave portion forming surface by the direction side wall portion 71. .

  Further, as shown in FIGS. 4A and 4B, a guide portion for guiding the start of press-fitting is provided on the inboard side of the recess 36 formed in advance in the shaft hole 34 of the hub wheel 1. The guide portion is formed with a concave portion 38 larger than the convex portion 33 of the stem portion 30 (see an enlarged portion in FIG. 2). That is, a gap m is formed between the convex portion 33 and the concave portion 38. By this guide portion, when the stem portion 30 of the outer joint member 20 is press-fitted into the hub wheel 1, the convex portion 33 of the stem portion 30 can be guided to be surely press-fitted into the concave portion 36 of the hub wheel 1. Thus, stable press-fitting is possible, and misalignment and tilting during press-fitting can be prevented.

  Further, a protruding portion 39 generated by the transfer of the convex shape by press-fitting (cutting and accompanying plastic deformation or elastic deformation) between the shaft hole 34 of the hub wheel 1 and the stem portion 30 of the outer joint member 20. Is provided [see FIG. 5 (A) and FIG. 6 (A)]. The housing portion 40 is formed between the shaft end of the stem portion 30 of the outer joint member 20 and the inner peripheral surface of the shaft hole 34 of the hub wheel 1 by making the shaft end small. Accordingly, the protruding portion 39 generated by the transfer of the convex shape by press-fitting can be held in the accommodating portion 40, and the protruding portion 39 can be prevented from entering the vehicle outside the apparatus. By holding the protruding portion 39 in the accommodating portion 40, it is not necessary to remove the protruding portion 39, the work man-hours can be reduced, the workability can be improved, and the cost can be reduced. .

  As shown in FIGS. 1 to 3, the wheel bearing device includes the following screw tightening structure N, and the work of press-fitting the stem portion 30 of the outer joint member 20 into the shaft hole 34 of the hub wheel 1 is performed as follows. The screw tightening structure N is used. The screw tightening structure N includes an internal thread portion 41 formed at the shaft end of the stem portion 30 of the outer joint member 20 and a bolt 42 that is an external thread portion that is engaged with the internal thread portion 41 and is locked to the hub wheel 1. It consists of and. In this structure, the bolt 42 is inserted into the through hole 44 of the projecting wall portion 43 formed in the shaft hole 34 of the hub wheel 1 and screwed into the female screw portion 41 of the stem portion 30, and the bolt 42 is connected to the hub wheel 1. By tightening in a state of being engaged with the protruding wall portion 43, the outer joint member 20 of the constant velocity universal joint 7 is pulled in, and the stem portion 30 of the outer joint member 20 is press-fitted into the shaft hole 34 of the hub wheel 1. The universal joint 7 is fixed to the hub wheel 1. The shoulder 45 of the outer joint member 20 is brought into contact with the caulking portion 13 of the hub wheel 1 by tightening the bolt 42.

  When the recess 30 is formed by transferring the shape of the circumferential side wall 71 of the convex portion 33 to the shaft hole 34 of the hub wheel 1 when the stem portion 30 is press-fitted into the hub wheel 1, the circumferential side wall of the convex portion 33 is formed. Since the concave portion 36 having the tightening allowance n with respect to only the portion 71, that is, the concave portion 36 whose circumferential dimension is set smaller than that of the convex portion 33 is formed in advance (see FIG. 5B), the bolt 42 The outer joint member 20 can be press-fitted into the hub wheel 1 with an axial force generated by the tightening of. That is, it becomes easy to press-fit the outer joint member 20 into the hub wheel 1 of the wheel bearing 6 with the pulling force of the bolt 42 to couple the constant velocity universal joint 7 to the wheel bearing 6. It is possible to improve the performance and prevent damage to the parts during the assembly.

  Thus, when the outer joint member 20 is press-fitted into the hub wheel 1 of the wheel bearing 6, it is not necessary to prepare a dedicated jig separately, and the bolt 42, which is a component constituting the wheel bearing device, has a constant velocity. The universal joint 7 can be easily coupled to the wheel bearing 6. In addition, since it is possible to press-fit by applying a relatively small pulling force equal to or less than the axial force generated by tightening the bolt 42, the pulling workability by the bolt 42 can be improved. Furthermore, since it is not necessary to apply a large press-fitting load, it is possible to prevent the unevenness in the concave-convex fitting structure M from being damaged (peeled), and to realize a high-quality, long-life concave-convex fitting structure M.

  A screw tightening structure N in which the shoulder 45 of the outer joint member 20 is brought into contact with the caulking portion 13 of the hub wheel 1 by tightening the bolt 42 as described above. In this wheel bearing device, since the outer joint member 20 can be press-fitted into the hub wheel 1 below the axial force generated by tightening the bolt 42, the axial force generated by tightening the bolt 42 and the hub The difference from the axial force generated by the pressure input of the outer joint member 20 to the wheel 1 is set to 32 kN or less, preferably 28 kN or less. This is because the difference between the axial force generated by tightening the bolt 42 and the axial force generated by the pressure input of the stem portion 30 to the hub wheel 1, that is, the shoulder of the caulking portion 13 of the hub wheel 1 and the outer joint member 20. The axial force generated on the contact surface with the portion 45 is 32 kN or less.

  Here, the conventional wheel bearing device (see FIG. 28) employs a fitting structure between the female spline 113 of the shaft hole of the hub wheel 101 and the male spline 126 of the stem portion 125 of the outer joint member 123. From this, the axial force generated by tightening the nut 127 becomes the axial force generated on the contact surface between the caulking portion 114 of the hub wheel 101 and the shoulder portion 128 of the outer joint member 123. That is, the axial force generated by tightening the nut 127 is equal to the axial force generated on the contact surface between the caulking portion 114 of the hub wheel 101 and the shoulder portion 128 of the outer joint member 123.

  On the other hand, in the wheel bearing device of this embodiment, when the bolt 42 is tightened, the concave portion 36 having a tightening margin n with respect to the circumferential side wall portion 71 of the convex portion 33 of the stem portion 30 of the outer joint member 20 is provided. In a state in which the shaft hole 34 of the hub wheel 1 is formed in advance, the concave portion forming surface is slightly cut by the circumferential side wall portion 71 of the convex portion 33, and the concave portion forming surface by the circumferential side wall portion 71 of the convex portion 33 is formed. The stem portion 30 of the outer joint member 20 is press-fitted into the shaft hole 34 of the hub wheel 1 with accompanying slight plastic deformation and elastic deformation, and the circumferential side wall portion 71 of the convex portion 33 is formed in the concave portion forming surface. The structure in which the concave portion 37 is formed by transferring the shape is adopted [see FIGS. 5A and 5B]. From this, the difference between the axial force generated by tightening the bolt 42 and the axial force generated by pressure input of the outer joint member 20 to the hub wheel 1 is the difference between the caulking portion 13 of the hub wheel 1 and the outer joint member 20. This is the axial force generated on the contact surface with the shoulder 45.

  That is, the axial force generated on the contact surface between the crimped portion 13 of the hub wheel 1 and the shoulder 45 of the outer joint member 20 is equal to the axial force generated by the pressure input of the outer joint member 20 to the hub wheel 1. The axial force generated by tightening the bolt 42 can be made smaller. In this way, the surface pressure at the contact surface between the caulking portion 13 of the hub wheel 1 and the shoulder portion 45 of the outer joint member 20 can be reduced as compared with the conventional wheel bearing device. When rotational torque is applied from the constant velocity universal joint 7 to the wheel bearing 6 at the time of starting, it is possible to avoid a sudden slip on the contact surface, and to prevent the occurrence of stick-slip noise. it can.

  FIG. 7 shows the test results based on the axial force measurement performed by the present applicant. The axial force generated by tightening the bolt 42 and the axial force generated by the pressure input of the outer joint member 20 to the hub wheel 1 are measured. The present invention (Nos. 1 to 7) and comparative products (Nos. 8 to 13) were confirmed for the presence or absence of stick-slip noise.

  As shown in FIG. 8, the axial force generated by tightening the bolt 42 is measured by forming a hole 47 in the head 46 of the bolt 42 and installing a strain gauge 48 embedded in the hole 47 with an adhesive 49. Use it. The strain gauge 48 is disposed in an embedded state in the shaft root portion 50 of the bolt 42. In order to convert the strain value measured by the strain gauge 48 into an axial force, a tensile test of the bolt 42 in which the strain gauge 48 is embedded is performed in advance, and the relationship between the strain value and the axial force is calibrated. The axial force generated by the pressure input of the outer joint member 20 to the hub wheel 1 is measured when the stem portion 30 of the outer joint member 20 is press-fitted into the shaft hole 34 of the hub wheel 1 separately from the pull-in by the bolt 42. Connect to a tensile and compression tester and measure the pressure input.

  In the test based on this axial force measurement, as shown in FIG. 7, the difference between the axial force generated by tightening the bolt 42 and the axial force generated by the pressure input of the outer joint member 20 to the hub wheel 1, that is, the hub. In the products of the present invention (Nos. 1 to 7) in which the axial force generated on the contact surface between the crimped portion 13 of the wheel 1 and the shoulder portion 45 of the outer joint member 20 is 32 kN or less, no stick-slip noise is generated. It was. On the other hand, in the comparative product (No. 8 to 13) in which the axial force generated on the contact surface between the caulking portion 13 of the hub wheel 1 and the shoulder portion 45 of the outer joint member 20 is larger than 32 kN, stick slip The result was that sound was generated. In addition, it is preferable that the axial force which generate | occur | produces in the contact surface of the crimping part 13 of the hub wheel 1 and the shoulder part 45 of the outer joint member 20 shall be 28 kN or less. This 28 kN is an average value of the axial force of the product of the present invention (Nos. 1 to 7).

  Further, in the wheel bearing device of this embodiment, as shown in FIG. 2, the convex portion 33 (the raised portion of the male spline) from the shoulder portion 45 of the outer joint member 20 with which the caulking portion 13 of the hub wheel 1 abuts. The value obtained by dividing the axial length L1 up to the maximum outer diameter D of the stem portion 30 is 0.3 or less, and the axial length L2 of the stem portion 30 (from the shoulder 45 to the convex portion 33 of the outer joint member 20). The value obtained by dividing the axial length to the outboard side end) by the maximum outer diameter D of the stem portion 30 is 1.3 or less. Here, the maximum outer diameter D of the stem portion 30 means the tip end outer diameter at the convex portion 33 (male spline).

  Thus, by setting the axial lengths L1 and L2 with respect to the maximum outer diameter D of the stem portion 30, when the rotational torque is applied from the constant velocity universal joint 7 to the wheel bearing 6 at the time of vehicle start, The amount of twist of the outer joint member 20 can be reduced while ensuring the effective fitting length in the concave-convex fitting structure M. As a result, it is possible to reliably avoid the occurrence of a sudden slip at the contact surface between the caulking portion 13 of the hub wheel 1 and the shoulder portion 45 of the outer joint member 20, and to further prevent the occurrence of stick-slip noise. can do.

  The value obtained by dividing the axial length L1 from the shoulder 45 of the outer joint member 20 to the convex portion 33 by the maximum outer diameter D of the stem portion 30 is greater than 0.3, or the axis of the stem portion 30 If the value obtained by dividing the direction length L2 by the maximum outer diameter D of the stem portion 30 is larger than 1.3, it is difficult to ensure an effective fitting length in the concave-convex fitting structure M, or when torque is applied It becomes difficult to reduce the amount of twist of the outer joint member 20. As a result, sudden slip is likely to occur on the contact surface between the caulking portion 13 of the hub wheel 1 and the shoulder portion 45 of the outer joint member 20, and it is difficult to prevent the occurrence of stick-slip noise.

  Although the above embodiment demonstrated the case where it set so that only the circumferential side wall part 71 [refer FIG.5 (B)] of the convex part 33 had the interference allowance n, FIG.9 (A) (B) 11A and 11B, not only the circumferential side wall portion 71 of the convex portion 33 but also the portion including the radial tip portion 72 thereof, that is, from the mountain-shaped abdominal portion of the convex portion 33. The tightening allowance n may be set in a region reaching the top of the mountain shape. In this manner, the concave portion 36 is set smaller than the convex portion 33 so that the entire region of the concave portion 36 has a fastening margin n with respect to the circumferential side wall portion 71 and the radial front end portion 72 of the convex portion 33. Thus, in order to set the concave portion 36 smaller than the convex portion 33, the circumferential dimension and the radial dimension of the concave portion 36 may be made smaller than the convex portion 33.

  Also in the case of this embodiment, as shown in FIGS. 9A and 9B, when the stem portion 30 of the outer joint member 20 is press-fitted into the hub wheel 1, the guide portion (concave portion 38) causes the projection of the stem portion 30. The portion 33 is guided so as to be surely press-fitted into the recess 36 of the hub wheel 1. Then, as shown in FIGS. 10A and 10B, the recess forming surface is slightly cut by the circumferential side wall portion 71 and the radial tip portion 72 of the convex portion 33, and the circumferential side wall portion of the convex portion 33 is processed. The shape of the circumferential side wall portion 71 and the radial tip portion 72 of the convex portion 33 is formed on the concave portion forming surface while accompanying slight plastic deformation and elastic deformation of the concave portion forming surface by the 71 and the radial tip portion 72. Transcript. At this time, the convex portion 33 bites into the concave portion forming surface, so that the inner diameter of the hub wheel 1 is slightly increased, and the relative movement in the axial direction of the convex portion 33 is allowed. When the axial relative movement of the convex portion 33 stops, as shown in FIGS. 11A and 11B, the shaft hole 34 of the hub wheel 1 is reduced in diameter to return to the original diameter, and the hub is reduced. A recess 37 is formed in the shaft hole 34 of the wheel 1.

  In the embodiment shown in FIGS. 4 (A), 4 (B) to 6 (A), (B), the tightening allowance is limited only to the circumferential side wall 71 (see FIG. 5 (B)) of the protrusion 33. n is set. On the other hand, in the embodiment shown in FIGS. 9A, 9B, 11A, and 11B, the circumferential side wall 71 and the radial tip 72 of the convex portion 33 (see FIG. 10B). ] Is set so as to have an interference n. Here, in the case of an embodiment in which only the circumferential side wall 71 of the convex portion 33 is set to have a fastening allowance n, the circumferential side wall 71 and the radial front end 72 of the convex portion 33 are set. The press-fit load can be lowered as compared with the embodiment in which the tightening allowance n is set.

  The wheel bearing device of the embodiment shown in FIGS. 12 to 27 includes a seal structure that prevents muddy water and the like from entering the uneven fitting structure M for the purpose of rust prevention of the uneven fitting structure M. To do. In this embodiment, since the configuration other than the seal structure is the same as that of the above-described embodiment shown in FIGS. 1 to 11, the same reference numerals as those in FIGS.

  12 to 15 includes a structure in which a cylindrical seal 52 is interposed between the stem portion 30 of the outer joint member 20 and the protruding wall portion 43 of the hub wheel 1. The seal 52 is preferably an elastic member made of rubber or resin. The inboard side end portion 53 of the seal 52 is fitted into and fixed to the small diameter portion of the shaft end that is the accommodating portion 40 formed in the stem portion 30 (see FIGS. 14 and 15), and the outer joint member is tightened when the bolt 42 is tightened. By pulling the 20 stem portions 30, the outboard side end portion 54 of the seal 52 is pressed against the projecting wall portion 43 of the hub wheel 1 to be brought into close contact with a predetermined tightening margin (see FIGS. 12 and 13). In this way, the through hole 44 of the projecting wall portion 43 of the hub wheel 1 through which the bolt 42 is inserted by the seal 52 interposed between the stem portion 30 of the outer joint member 20 and the projecting wall portion 43 of the hub wheel 1. Even if muddy water or the like intrudes from, the muddy water or the like is prevented from reaching the uneven fitting structure M.

  In the embodiment shown in FIGS. 16 and 17, a seal 55 having a cylindrical shape is provided between the projecting wall 43 of the hub wheel 1 and the bolt 42. The seal 55 is preferably an elastic member made of rubber or resin. The seal 55 fixes the outer peripheral surface to the inner diameter of the through-hole of the projecting wall portion 43 of the hub wheel 1 with an adhesive or the like, thereby bringing the inner peripheral surface into close contact with the shaft root portion 50 of the bolt 42 with a predetermined tightening margin. Alternatively, by fixing the inner peripheral surface to the shaft base portion 50 of the bolt 42 with an adhesive or the like, the outer peripheral surface is brought into close contact with the inner diameter of the through hole of the projecting wall portion 43 of the hub wheel 1 with a predetermined tightening margin. . In this way, by the seal 55 interposed between the projecting wall portion 43 of the hub wheel 1 and the bolt 42, the concave-convex fitting structure M is formed from the through hole 44 of the projecting wall portion 43 of the hub wheel 1 through which the bolt 42 is inserted. Prevents muddy water from entering.

  In the embodiment shown in FIGS. 18 and 19, the seal 56 having a cylindrical shape and provided with a flange portion 57 projecting radially outward at the end portion on the outboard side is connected to the projecting wall portion 43 of the hub wheel 1 and the bolt 42. And a structure interposed therebetween. The seal 56 is preferably an elastic member made of rubber or resin. Since the attachment structure and the sealing function of the seal 56 are the same as those of the seal 55 in the embodiment shown in FIGS. In the case of the seal 56, since the flange portion 57 is provided at the end portion on the outboard side, the axial position of the hub wheel 1 with respect to the protruding wall portion 43 can be restricted. As a result, when the outer peripheral surface of the seal 56 is fixed to the protruding wall portion 43 of the hub wheel 1, the attachment becomes easy. Furthermore, when the outer joint member 20 is pulled in with the bolts 42, the flange portion 57 can prevent the seal 56 from moving (in the position) to the inboard side. Further, when the inner peripheral surface of the seal 56 is fixed to the shaft root portion 50 of the bolt 42, the creepage distance on the outer peripheral surface that is in close contact with the inner diameter of the through-hole of the projecting wall portion 43 of the hub wheel 1 can be increased and the seal 56 is sealed. The property is further improved.

  In the embodiment shown in FIGS. 20 and 21, a structure in which a lip-attached seal 60 in which a lip member 59 is mounted on the inner diameter of the tip end portion of a metal seal member 58 is interposed between the outer joint member 20 and the inner ring 2 is employed. It has. The lip member 59 is preferably an elastic member made of rubber or resin. The seal 60 is fixed by fitting the base end portion of the seal member 58 to the end portion of the inner ring 2, and the lip member 59 attached to the inner diameter of the distal end portion of the seal member 58 is fixed to the outer periphery of the shoulder portion 45 of the outer joint member 20. Close contact with the surface by elastic contact. In this manner, the seal 60 interposed between the shoulder 45 of the outer joint member 20 and the inner ring 2 is used to fit the concave and convex portions between the caulking portion 13 of the hub wheel 1 and the shoulder 45 of the outer joint member 20. Prevents muddy water from entering the structure M.

  In the embodiment shown in FIGS. 22 and 23, a structure in which a metal labyrinth seal 61 is interposed between the outer joint member 20 and the inner ring 2 is provided. The seal 61 has the cylindrical base end portion 62 fitted and fixed to the end portion of the inner ring 2, and the bent distal end portion 63 is brought close to the outer peripheral surface of the shoulder portion 45 of the outer joint member 20. In this way, due to the labyrinth structure at the curved tip portion 63 of the seal 61 interposed between the shoulder 45 of the outer joint member 20 and the inner ring 2, the caulking portion 13 of the hub wheel 1 and the outer joint member 20 are Muddy water or the like is prevented from entering the concave-convex fitting structure M from between the shoulder 45.

  In the embodiment shown in FIGS. 24 and 25, a seal 66 with a lip in which a lip member 65 made of rubber or resin is attached to the tip of a metal seal member 64 is provided between the outer joint member 20 and the inner ring 2. It has an intervening structure. The lip member 65 is preferably an elastic member made of rubber or resin. The seal 66 is fixed by fitting the base end portion of the seal member 64 into the shoulder portion 45 of the outer joint member 20, and the lip member 65 attached to the distal end portion of the seal member 64 by elastic contact with the end surface of the inner ring 2. Adhere closely. In this way, the seal 66 interposed between the shoulder 45 of the outer joint member 20 and the inner ring 2 is used to fit the concave and convex portions between the caulking portion 13 of the hub wheel 1 and the shoulder 45 of the outer joint member 20. Prevents muddy water from entering the structure M.

  In the embodiment shown in FIGS. 26 and 27, a structure in which a metal labyrinth seal 67 is interposed between the outer joint member 20 and the inner ring 2 is provided. The seal 67 has its cylindrical base end portion 68 fitted and fixed to the shoulder portion 45 of the outer joint member 20, and its bent distal end portion 69 is brought close to the end surface of the inner ring 2. In this way, due to the labyrinth structure at the bent distal end 69 of the seal 67 interposed between the shoulder 45 of the outer joint member 20 and the inner ring 2, the caulking portion 13 of the hub wheel 1 and the outer joint member 20 are Muddy water or the like is prevented from entering the concave-convex fitting structure M from between the shoulder 45.

  In the above embodiment, the screw tightening structure N is illustrated in which the bolt 42 is screwed to the female thread portion 41 of the stem portion 30 and the bolt 42 is fastened to the protruding wall portion 43 of the hub wheel 1. As another screw tightening structure, a male screw portion formed at the shaft end of the stem portion 30 of the outer joint member 20 and a female screw locked to the protruding wall portion 43 of the hub wheel 1 in a state of being screwed to the male screw portion. It is also possible to configure with a nut which is a part.

  In the above embodiment, the end of the small-diameter step portion 11 of the hub wheel 1 is swaged outward by swing caulking, and the inner ring 2 is prevented from coming off by the caulking portion 13 and integrated with the hub wheel 1. In this example, the caulking structure in which the constant velocity universal joint 7 is separable from the wheel bearing 6 is illustrated, but the inner ring 2 is press-fitted into the small-diameter step portion 11 of the hub wheel 1, and the end of the inner ring 2 is outside A non-caulking structure that abuts against the shoulder 45 of the joint member 20 may be used.

  Furthermore, in the above embodiment, one of the double-row inner raceway surfaces 8, 12 formed on the inner member composed of the hub wheel 1 and the inner ring 2, that is, the inner raceway surface 8 on the outboard side is connected to the hub wheel 1. An example of application to a wheel bearing device of the type formed on the outer periphery (referred to as the third generation) is illustrated, but a pair of inner rings are press-fitted into the outer periphery of the hub wheel 1, and the track surface 8 on the outboard side is The present invention can also be applied to a type of wheel bearing device (referred to as the first and second generations) in which the inboard side raceway surface 12 is formed on the outer periphery of the other inner ring.

  The present invention is not limited to the above-described embodiments, and can of course be implemented in various forms without departing from the gist of the present invention. It includes the equivalent meanings recited in the claims and the equivalents recited in the claims, and all modifications within the scope.

1 Inner member (hub ring)
2 Inner member (inner ring)
3, 4 Rolling element 5 Outer member (outer ring)
6 Wheel bearing 7 Constant velocity universal joint 8, 12 Inner raceway surface 14, 15 Outer raceway surface 20 Outer joint member 30 Stem portion 33 Convex portion (male spline)
36, 37 Concave part 41 Female thread part 42 Male thread part (bolt)
45 Shoulder n Tightening allowance M Concavity and convexity fitting structure N Screw tightening structure X All fitting contact areas

Claims (4)

An outer member having a double-row outer raceway surface formed on the inner periphery, a double-row inner raceway surface facing the outer raceway surface on the outer periphery, and an inner member comprising a hub ring and an inner ring; An outer joint member of a constant velocity universal joint provided on the inner diameter of the hub wheel, comprising a bearing for a wheel comprising a double row rolling element interposed between an outer raceway surface of the inner member and an inner raceway surface of the inner member. A wheel bearing device in which a constant velocity universal joint is coupled to the wheel bearing by a screw tightening structure by fitting a stem portion of the outer joint member and a shoulder portion of the outer joint member is brought into contact with an end portion of the inner member. In
A plurality of recesses having an allowance for a plurality of protrusions formed in any one of the hub wheel and the stem portion of the outer joint member and extending in the axial direction only with respect to a circumferential side wall portion of the protrusions. Is formed by cutting the recess forming surface by the circumferential side wall portion of the convex portion with a pulling force less than the axial force generated by screw tightening , and the shape of the circumferential side wall portion of the convex portion is formed in the other direction. by transferring, the convex portions and the fitting contact regions entire region in close contact with the recess, the recess constitutes a recess-projection fitting structure which have a gap with respect to the radial tip of the convex portion, the clamping screw A wheel bearing device, wherein a difference between an axial force generated and an axial force generated by pressure input is 32 kN or less.   The screw tightening structure includes an internal thread portion formed at a shaft end of a stem portion of the outer joint member, and an external thread portion that is engaged with the internal thread portion and is engaged with the hub ring. Item 2. A wheel bearing device according to Item 1.   The wheel bearing device according to claim 1 or 2, wherein the convex portion is provided on a stem portion of the outer joint member, and the concave portion is provided on the hub wheel.   A value obtained by dividing the axial length from the shoulder portion of the outer joint member to which the end portion of the inner member abuts to the convex portion by the maximum outer diameter of the stem portion is 0.3 or less, and The wheel bearing device according to claim 3, wherein a value obtained by dividing the axial length by the maximum outer diameter of the stem portion is 1.3 or less.

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