WO2010044344A1

WO2010044344A1 - Wheel bearing apparatus

Info

Publication number: WO2010044344A1
Application number: PCT/JP2009/067027
Authority: WO
Inventors: 清武柴田; 清茂山内; 小澤　仁博
Original assignee: Ntn株式会社
Priority date: 2008-10-14
Filing date: 2009-09-30
Publication date: 2010-04-22

Abstract

A wheel bearing apparatus unifies a hub (1) for mounting a wheel, multiple rolling bearings (2) and a constant velocity universal joint (3). A shaft (12) of an external joint member (5) of the constant velocity universal joint (3) is fitted in a hole (22) in the hub (1), a projection extending axially and provided on either the inner circumferential surface of the hole (22) in the hub (1) or the outer circumferential surface of the shaft (12) of the external joint member (5) is pressed into the other in the axial direction, a recess that fits tightly on the projection is formed on the other at the projection, and a projection-and-recess fitting mechanism (M) is configured wherein the entire area of the contact location where the projection and recess are fitted is tight. The hub (1) and the external joint member (5) are fastened so as to be separated or reassembled by inserting a bolt (54) through a through-hole (56) formed in an inside wall (22c) of the hub (1), and the coaxiality of the through-hole (56) relative to the hole (22) in the hub (1) is stipulated to be no longer than 1.0 mm.

Description

Wheel bearing device

This invention relates to a wheel bearing device for rotatably supporting a wheel with respect to a vehicle body in a vehicle such as an automobile.

The wheel bearing device has evolved from a structure in which a double-row rolling bearing called a first generation is used alone to a second generation in which a vehicle body mounting flange is integrated with an outer member. The third generation in which one inner raceway (inner race) of a double row rolling bearing is formed on the outer periphery of the hub having an integral, and the hub and the constant velocity universal joint are integrated. Up to the fourth generation, in which the other inner raceway (inner race) of the double row rolling bearing is formed on the outer periphery of the outer joint member to be formed.

Patent Document 1 describes a third-generation wheel bearing device. As shown in FIG. 12, the wheel bearing device includes a hub 102 having a flange 101 extending in the outer diameter direction, a constant velocity universal joint 104 in which an outer joint member 103 is fixed to the hub 102, and an outer peripheral side of the hub 102. The outer member 105 is provided.

The constant velocity universal joint 104 includes the outer joint member 103, an inner joint member 108 housed in the bowl-shaped portion 107 of the outer joint member 103, and a ball interposed between the inner joint member 108 and the outer joint member 103. 109 and a holder 110 that holds the ball 109. A spline 111 is formed on the inner peripheral surface of the center hole of the inner joint member 108, and is splined to a spline shaft of a shaft (not shown).

The hub 102 has a cylindrical portion 113 and the flange 101, and a short cylindrical pilot portion 115 for mounting a wheel and a brake rotor (not shown) on the outer end surface (end surface on the opposite joint side) 114 of the flange 101. Is formed. The pilot portion 115 includes a large-diameter first portion 115a and a small-diameter second portion 115b. The brake rotor is fitted to the first portion 115a and the wheel is fitted to the second portion 115b.

A small-diameter portion 116 is provided on the outer peripheral surface of the cylindrical portion 113 on the side of the saddle-shaped portion 107, and an inner ring 117 is fitted to the small-diameter portion 116. A first inner race (inner race) 118 is formed near the flange on the outer peripheral surface of the cylindrical portion 113 of the hub 102, and a second inner race (inner race) 119 is formed on the outer peripheral surface of the inner ring 117. The flange 101 of the hub 102 has a bolt mounting hole 112, and the wheel and brake rotor are fixed to the flange 101 by a hub bolt (not shown) implanted in the bolt mounting hole 112.

The outer member 105 has two rows of outer tracks (outer races) 120 and 121 formed on the inner periphery, and a flange (vehicle body mounting flange) 132 formed on the outer periphery. The first inner track 118 of the hub 102 and the first outer track 120 of the outer member 105 face each other, and the second inner track 119 of the inner ring 117 and the second outer track 121 of the outer member 105 face each other. Two rows of rolling elements 122 are interposed therebetween.

A spline portion 126 is formed on the inner peripheral surface of the cylindrical portion 113 of the hub 102. The shaft portion 123 has a screw portion 124 formed at the tip, and a spline portion 125 is formed between the screw portion 124 and the hook-shaped portion 107. Then, the shaft portion 123 of the outer joint member 103 is inserted into the cylindrical portion 113 of the hub 102, and the spline portion 125 of the shaft portion 123 and the spline portion 126 of the hub 102 are engaged with each other, whereby the hub 102 and the outer joint member 103 are connected. It can be coupled to transmit torque.

When the nut 127 is attached to the screw portion 124 of the shaft portion 123 protruding from the tube portion 113 and tightened, the seat surface 128 of the nut 127 and the outer end surface 129 of the tube portion 113 are brought into close contact with each other, and The end surface 130 and the outer end surface 131 of the inner ring 117 are in close contact with each other. That is, by tightening the nut 127, the hub 102 is sandwiched between the nut 127 and the hook-shaped portion 107 via the inner ring 117.
JP 2004340403 A

Conventionally, as described above, a coupling structure capable of transmitting torque has been obtained by engaging the spline portion 125 of the shaft portion 123 and the spline portion 126 of the hub 102. For this reason, it is necessary to perform spline processing on both the shaft portion 123 and the hub 102, which not only increases the cost but also matches the unevenness of the spline portion 125 of the shaft portion 123 and the spline portion 126 of the hub 102 during press-fitting. There is a need. Furthermore, if the teeth are pressed together by matching the tooth surfaces, the uneven teeth may be damaged (peeled). Moreover, if it press-fits by matching the large diameter of an uneven | corrugated tooth | gear, without matching a tooth surface, it will be easy to produce the play of the circumferential direction. If there is a backlash in the circumferential direction, the transmission performance of the rotational torque is inferior and abnormal noise may be generated. Thus, in the case of spline fitting, it has been difficult to remove both the damage to the uneven teeth and the play in the circumferential direction at the same time.

Further, it is necessary to screw the nut member 127 to the screw portion 124 of the shaft portion 123 protruding from the tube portion 113. For this reason, it has a screw fastening operation at the time of assembly, and is inferior in workability, has a large number of parts, and is inferior in parts manageability.

The object of the present invention is to suppress circumferential play, and the hub and the outer joint member of the constant velocity universal joint can be separated and reassembled, and the hub and the outer joint member of the constant velocity universal joint can be separated. An object of the present invention is to provide a wheel bearing device that is easy to assemble and is low in cost.

The present invention includes an outer member having a double row outer race on the inner periphery, a hub provided with a flange for attaching a wheel, and an inner member having a double row inner race facing the outer race. A plurality of rolling elements disposed between the outer race and the inner race, and a constant velocity universal joint having an outer joint member, and the hub is fitted to a shaft portion of the outer joint member of the constant velocity universal joint. In the wheel bearing device provided with the hole portion, an axially extending convex portion provided on either the inner peripheral surface of the hub or the outer peripheral surface of the shaft portion of the outer joint member is provided along the axial direction. A concave and convex fitting structure is formed in which the whole of the fitting contact portion between the convex portion and the concave portion is in close contact with each other by forming a concave portion that is press-fitted into the other portion and is closely fitted to the convex portion by the convex portion. Fastening the shaft of the member with bolts The hub and the outer joint member can be separated and reassembled, and the hub is provided with a through hole for opening the hole and through which the bolt is inserted, and the through hole is formed with respect to the hole of the hub. The coaxiality is defined to be 1.0 mm or less.

Coaxiality refers to the magnitude of deviation from the datum axis line that should be on the same line as the datum axis line (theoretical accurate line set by the reference axis). This coaxiality is expressed by the diameter of the smallest cylinder among the geometric cylinders that include all the axes and are coaxial with the datum axis line. Coaxiality is a deviation with respect to the position of two axes, and since the axis must be determined from the surface of a rotationally symmetric body having a shape deviation in general, precise measurement requires labor and time. That is, using a roundness measuring device capable of recording and measuring the change in radius from the fixed center and the straightness in the direction of the rotation axis, first the axial straight line of the reference portion A of the object to be measured matches the rotation axis. Let Next, the center of the cylindrical body B in the cross section is determined by moving the object to be measured or the stylus in the direction of the rotation axis and recording a circular recording diagram in the necessary cross section. Of these centers, twice the distance from the center of rotation to the center of the farthest point is the coaxiality ("revised precision measurement (2)", January 15, 1985, 20th edition, stock Issued by the company Corona). According to JISB0182, the degree of coaxiality or coincidence is defined as the degree to which the axes of two mechanical parts arranged so as to have a common axis do not coincide.

The bolts are inserted from the through holes formed in the hub and the hub and the outer joint member are fastened, whereby the axial direction of the shaft portion of the outer joint member from the hub is restricted. At the time of separation, a jig is fixed to the hub flange using a hub bolt, and the pulling force is applied by the jig. When reassembling, the shaft portion of the outer joint member can be inserted into the hole of the hub, and the outer joint member can be pulled by turning the bolt.

The hub can be provided with an inner wall having a through hole, and a seating surface for the bolt can be formed on the side opposite to the hole on the inner wall of the hub. Thereby, the screwing state of the bolt is stabilized. Under the present circumstances, you may form the receiving surface which contacts the front-end | tip part of an outer joint member in the hole side of the inner wall of a hub. By adopting such a configuration, the hub and the outer joint member can be positioned in the axial direction.

For example, the convex portion of the concave-convex fitting structure is provided on the shaft portion of the outer joint member, and at least the hardness of the end portion in the axial direction of the convex portion is made higher than the inner diameter portion of the hole portion of the hub. The shaft portion is press-fitted into the hole portion of the hub from the axial end side of the convex portion, and the convex portion is formed with a concave portion that closely fits the convex portion on the inner peripheral surface of the hole portion of the hub. Can also be configured.

At that time, the convex part bites into the concave part forming surface on the other side (the inner peripheral surface of the hole part of the hub), so that the hole part is slightly expanded in diameter and allows the convex part to move in the axial direction. When the movement in the axial direction is stopped, the hole portion is reduced in diameter to return to the original diameter. Thereby, the whole recessed part fitting part of a convex part closely_contact | adheres to the corresponding recessed part. The hardness difference between the hub and the outer joint member is 20 points or more in terms of HRC (Rockwell hardness C scale).

A convex part of the concave-convex fitting structure is provided on the shaft part of the outer joint member, and the hardness of the axial end part of this convex part is made higher than the inner diameter part of the hole part of the hub so that the shaft part becomes the hole part of the hub. If it press-fits from the axial direction edge part side of a convex part, the hardness by the side of a shaft part can be made high and the rigidity of a shaft part can be improved.

The inner member is composed of, for example, a hub and an inner ring each having one row of inner races. Both can be fixed by fitting the inner ring to the hub and caulking the end of the hub. By caulking the end portion of the hub, the interval between the two inner races is reduced, and bearing preload is applied. Thus, since the preload is applied to the bearing by caulking the end of the hub, the outer joint member does not need to be involved in the bearing preload. For this reason, it is possible to press-fit the shaft portion of the outer joint member without considering the bearing preload, and it is possible to improve the connectivity (assembly property) between the hub and the outer joint member. Various types of caulking are known, and an example is swing caulking.

A small diameter in which a storage portion for storing a protruding portion generated by forming a concave portion by press-fitting is provided on the outer diameter side of the shaft portion on the anti-joint side than the concave-convex fitting structure, and the storage portion is formed at the tip of the shaft portion of the outer joint member It is preferably formed by a stepped portion and a hub. Here, the protruding portion is a material content of the capacity of the concave portion into which the concave portion fitting portion of the convex portion is inserted, and is extruded from the formed concave portion, cut to form the concave portion, or extruded. It consists of both the cut and the cut. The outer diameter of the small diameter step portion forming the storage portion is larger than the inner diameter of the through hole of the hub.

By providing a storage portion for storing the protruding portion that is generated by forming the concave portion by press-fitting, the protruding portion can be held (maintained) in the storage portion, and the protruding portion does not enter the inside of the vehicle outside the apparatus. . In other words, the protruding portion can be kept stored in the storage portion, and it is not necessary to perform the removal processing of the protruding portion, the number of assembling work can be reduced, and the assembling workability can be improved and the cost can be reduced. You can plan.

For the reasons described below, it is preferable that the concave / convex fitting portion is disposed at a position avoiding a position directly below the raceway surface of the rolling bearing. That is, when the shaft portion of the outer joint member is press-fitted into the hole portion of the hub, the hub expands. By this expansion, a hoop stress is generated on the raceway surface (inner race) of the rolling bearing. Here, the hoop stress refers to a force for expanding the diameter in the outer diameter direction. When a hoop stress is generated on the bearing raceway surface, there is a risk of causing a reduction in rolling fatigue life and occurrence of cracks. Therefore, by arranging the concave-convex fitting structure directly under the raceway surface of the rolling bearing, for example, between the rolling element rows, generation of hoop stress on the bearing raceway surface can be suppressed.

A large-diameter portion having an inner diameter larger than the outer diameter of the convex portion of the shaft portion and having irregularities formed in the circumferential direction may be provided in the hole portion of the hub. The large diameter portion is located on the joint side with respect to the fitting hole into which the shaft portion of the outer joint member is press-fitted, and acts as a guide groove when the shaft portion is press-fitted. That is, when reassembling after separation, it becomes easy to press-fit the convex portion into the concave portion formed last time, and the stability of reassembly can be improved without causing misalignment or inclination.

A screw hole is provided along the axial direction in the shaft core portion of the shaft portion of the outer joint member, and when the hub and the shaft portion of the outer joint member are separated from each other, the axial force is applied to the bolt screwed into the screw hole. By imparting, separation force can be generated in the outer joint member.

To separate the hub and the outer joint member, a detachable jig having a female screw is detachably attached to the hub, and the bolt is pressed by screwing of a pressing bolt member screwed into the female screw of the detaching jig. Can be performed.

In this case, it is preferable that the screw thread direction between the screw hole of the shaft portion of the outer joint member and the female screw of the detachment jig is opposite. Accordingly, by pushing the bolt member for pressing, a pressing force in the axial direction can be applied to the bolt, and the hub wheel and the shaft portion of the outer joint member can be separated. At this time, if the screw thread direction of the female screw to which the pressing bolt member is screwed and the screw hole to which the bolt is screwed are the same, the bolt rotates together when the pressing bolt member is screwed, The bolt will also be screwed into the screw hole. If the tip of the bolt is screwed to the bottom of the screw hole by this co-rotation, the separating force can be applied without rotating the screw, but the bolt is screwed until the tip of the bolt reaches the bottom of the screw hole. It takes a lot of work time. Further, in order to reach the tip of the bolt to the bottom of the screw hole, it is necessary to increase the length of the bolt, resulting in poor handling.

On the other hand, if the screw thread direction of the screw hole of the shaft portion of the outer joint member and the female screw of the removal jig is reversed, the bolt rotates together even if the pressing bolt member is screwed. There is no such thing, and a pressing force can be reliably applied to the bolt. In this case, the bolt can be used as it is at the time of separation, so that the separation workability can be improved and the cost can be reduced.

According to the present invention, the concave / convex fitting structure has the entire fitting contact portion between the convex portion and the concave portion in close contact with each other, so that in this fitting structure, there is a gap in which play occurs in the radial direction and the circumferential direction. Not. Moreover, the outer joint member can be removed from the hole of the hub by applying an axial pulling force to the shaft portion of the outer joint member. In addition, after the shaft portion of the outer joint member is pulled out from the hole portion of the hub, if the shaft portion of the outer joint member is pressed into the hole portion of the hub again, the entire fitting contact portion between the convex portion and the concave portion is brought into close contact. The concave-convex fitting structure can be reconfigured.

Thus, the wheel bearing device of the present invention can be separated and reassembled. Then, by increasing the coaxiality of the through hole of the hub with respect to the hole of the hub, specifically, by defining it to be 1.0 mm or less, the relative movement in the axial direction of the hub and the outer joint member during separation and reassembly is performed. Can be smoothly performed using a bolt. In order to make effective use of the hub's through-holes and holes with increased coaxiality, the inner diameter of the hub's through-holes should be controlled so that the clearance between the bolt's corresponding part and the outer diameter is small. desirable. When the coaxiality of the through hole with respect to the hole of the hub is greater than 1.0 mm, when the outer joint member is press-fitted along the hub hole, the bolt inserted along the through hole is screwed into the female thread of the outer joint member. It will not be worn. That is, assembling becomes impossible by shifting the positions of each other.

By applying an axial pulling force to the shaft portion of the outer joint member, the outer joint member can be removed from the hole of the hub, so that the workability (maintenability) of repair and inspection of each part is improved. be able to. In addition, it is possible to constitute a concave-convex 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 shaft portion of the outer joint member into the hole of the hub again after repair and inspection of each part. it can. For this reason, the wheel bearing device capable of stable torque transmission can be configured again.

A convex portion provided on either the outer peripheral surface of the shaft portion of the outer joint member or the inner peripheral surface of the hole portion of the hub is press-fitted into the other along the axial direction, thereby closely fitting to the convex portion. A recess can be formed. For this reason, an uneven | corrugated fitting structure can be formed reliably. Moreover, since it is not necessary to form splines or the like on the member on the side where the recesses are formed, productivity is improved, and work efficiency is improved because it is not necessary to align the phases of the splines during assembly. Damage to the tooth surface during press-fitting can be avoided, and a stable fitting state can be maintained.

Since the structure is fastened with bolts, the shaft is prevented from coming off from the hub, and stable torque transmission is possible over a long period of time. In relation to this bolt fastening, the inner wall of the hub was sandwiched between the end face of the shaft portion of the outer joint member and the head of the bolt and used as a positioning means, so that the bolt fixing was stabilized and positioned. As a result, the dimensional accuracy of the wheel bearing device can be stabilized, and the axial length of the concave-convex fitting structure disposed along the axial direction can be secured to improve the torque transmission performance. Can be planned.

Hereinafter, embodiments of the present invention will be described with reference to FIGS. FIG. 2 shows the wheel bearing device of the first embodiment. This wheel bearing device is a unit in which a hub 1, a double-row rolling bearing 2, and a constant velocity universal joint 3 are unitized, and the constant velocity universal joint 3 inserted into the hub 1 and the hole 22 of the hub 1. The shaft portion 12 of the outer joint member is connected through the concave-convex fitting structure M so as to be separable.

As shown in FIG. 7, the constant velocity universal joint 3 includes an outer joint member 5, an inner joint member 6, a plurality of balls 7 as torque transmitting elements, and a cage 8 that holds the balls 7. It is said. The inner joint member 6 is spline-fitted by press-fitting the end portion 10a of the shaft 10 into the shaft hole inner diameter 6a, and is coupled to the shaft 10 so that torque can be transmitted. A retaining ring 9 for preventing the shaft from coming off is fitted to the end of the shaft 10.

The outer joint member 5 includes a mouth portion 11 and a shaft portion (stem portion) 12, and a back face 11a is formed at a boundary portion between the two. The mouse portion 11 has a bell shape with an end on the opposite side to the shaft portion 12 and has a spherical inner peripheral surface 13. A plurality of track grooves 14 extending in the axial direction are formed on the inner peripheral surface 13 at equal intervals in the circumferential direction.

The inner joint member 6 has a spherical outer peripheral surface 15, and a plurality of track grooves 16 extending in the axial direction are formed at equal intervals in the circumferential direction on the outer peripheral surface 15. The inner joint member 6 is spline-fitted with the spline shaft portion 10a of the shaft 10 through the spline hole 6a and is coupled to the shaft 10 so as to transmit torque. A retaining ring 9 is provided on the spline shaft portion 10a to prevent it from coming off.

The track groove 14 of the outer joint member 5 and the track groove 16 of the inner joint member 6 form a pair, and one ball 7 is incorporated in the ball track constituted by each pair of

track grooves

14 and 16 so that the balls 7 can roll. It is. The ball 7 is interposed between the track groove 14 of the outer joint member 5 and the track groove 16 of the inner joint member 6 to transmit torque. All balls 7 are held in the same plane by the cage 8. The cage 8 is slidably interposed between the inner peripheral surface 13 of the outer joint member 5 and the outer peripheral surface 15 of the inner joint member 6, and is in contact with the inner peripheral surface 13 of the outer joint member 5 at the outer peripheral surface. In contact with the outer peripheral surface 15 of the inner joint member 6.

In FIG. 7, a Rzeppa type is shown as an example of a fixed type constant velocity universal joint. However, an undercut free type having a straight straight portion at the groove bottom of each

track groove

14, 16 and other constant velocity universal joints. It may be.

The opening of the mouse portion 11 is closed with a boot 18 in order to prevent leakage of the lubricating grease filled in the interior and to prevent water and foreign matter from entering from the outside. The boot 18 includes a large diameter portion 18a, a small diameter portion 18b, and a bellows portion 18c that connects the large diameter portion 18a and the small diameter portion 18b. The large diameter portion 18a is attached to the outer periphery of the opening end portion of the mouse portion 11 and is fastened with a boot band 19a. The small diameter portion 18b is mounted on the boot mounting portion 10b of the shaft 10 and fastened with a boot band 19b.

As shown in FIGS. 1 and 6, the hub 1 includes a cylindrical portion 20 and a flange 21. The flange 21 is provided at the end of the cylindrical portion 20 on the side opposite to the joint (outboard side). The hub 1 has a hole 22 and a tapered hole 22b that are partitioned by an inner wall 22c. The inner wall 22c is in the form of an inward flange, and has a through hole 56 at the center. The hole 22 is located on the joint side (inboard side) with the inner wall 22c as a boundary, and the tapered hole 22b on the anti-joint side. Is located. A counterbore, that is, a seating surface 51 is formed on the surface of the inner wall 22c on the tapered hole 22b side. The surface on the hole 22 side of the inner wall 22c serves as a receiving surface 53 that contacts the end surface 52 of the shaft portion 12 of the outer joint member.

The hole portion 22 includes a fitting hole 22a and a large diameter portion 46 and a small diameter portion 48 arranged on both sides thereof. The large diameter portion 46 is located on the opening side of the fitting hole 22a, and the small diameter portion 48 is located on the inner wall 22c side of the fitting hole 22a. A tapered portion (tapered hole) 49a is provided between the large diameter portion 46 and the fitting hole 22a (FIG. 6). The taper part 49a is reduced in diameter in the press-fitting direction when the hub 1 and the shaft part 12 of the outer joint member 5 are coupled. For example, the angle θ of the tapered portion 49a is 15 ° to 75 °. A tapered portion 49 b is also provided between the fitting hole 22 a and the small diameter portion 48.

The rolling bearing 2 is mainly composed of an inner member (1, 24) corresponding to a bearing inner ring, an outer member 25 corresponding to a bearing outer ring, and a ball 30 as a rolling element. The inner member is composed of the hub 1 and the inner ring 24. The inner ring 24 is fitted to a small diameter portion 23 formed on the joint side of the cylindrical portion 20 of the hub 1. The hub 1 and the inner ring 24 each have a first inner raceway surface (inner race) 28 and a second inner raceway surface (inner race) 29. The outer member 25 has two rows of outer raceways (outer races) 26 and 27 on the inner periphery. The outer member 25 is attached to a knuckle 34 (see FIG. 7) extending from a vehicle suspension system (not shown). The first outer raceway surface 26 and the first inner raceway surface 28 face each other, and the second outer raceway surface 27 and the second inner raceway surface 29 face each other to form a track for the two rows of balls 30. The balls 30 in each row are held at a predetermined interval by a cage. In order to prevent the leakage of the lubricant and the entry of foreign matter from the outside, seal members S 1 and S 2 are attached to the opening portions at both ends of the outer member 25.

The end of the small diameter portion 23 of the hub 1 is caulked and plastically deformed radially outward, and the inner ring 24 is fixed in the axial direction with the caulking portion 31 applied to the end surface of the inner ring 24. In this state, a predetermined preload is applied to the rolling bearing 2. The mouth portion 11 of the outer joint member 5 and the end portion of the hub 1 (in this case, the caulking portion 31) are not in contact with each other, and a gap 58 exists between them (see FIG. 2). A hub bolt 33 is implanted in a bolt mounting hole 32 in the flange 21 of the hub 1, and the wheel and brake rotor are fixed to the flange 21 by the hub bolt 33.

The shaft portion 12 of the outer joint member 5 of the constant velocity universal joint is composed of a main body portion 12a and a small-diameter portion 12b on the distal end side, and a screw hole 50 is formed in the shaft center portion. The opening end portion of the screw hole 50 is a tapered portion 50a that expands toward the end face side of the shaft portion 12 (see FIG. 6).

As shown in FIG. 3A, a plurality of convex portions 35 extending in the axial direction are formed at a predetermined pitch in the circumferential direction on the outer peripheral surface of the shaft portion 12 on the side opposite to the mouse. On the inner peripheral surface 37 of the fitting hole 22a of the hub 1, a plurality of axially extending recesses 36 are formed at a predetermined pitch in the circumferential direction. As shown in FIG. 3B, the convex-concave fitting structure M is formed by the convex portion 35 and the concave portion 36, and the entire fitting contact portion 38 between the convex portion 35 and the concave portion 36 is in close contact. That is, the convex portion 35 and the concave portion 36 formed thereby are tight-fitted over the entire circumference.

The convex portion 35 has a triangular shape (mountain shape) having a convex arcuate cross section. The fitting contact part 38 of the convex part 35 and the recessed part 36 is a range from the mountain-shaped middle part to the mountain peak in the cross section, as shown by the symbol A. Further, a gap 40 exists between the convex portions 35 adjacent in the circumferential direction on the inner diameter side of the inner peripheral surface 37 of the fitting hole 22a of the hub 1.

Thus, the hub 1 and the shaft portion 12 of the outer joint member 5 are in a relationship capable of transmitting torque via the concave-convex fitting structure M.

Next, a manufacturing method of the uneven fitting structure M shown in FIG. A spline (or serration, the same applies hereinafter) 41 is formed on the shaft portion 12 of the outer joint member 5. This is a so-called male spline composed of convex teeth 41a and concave teeth 41b along the axial direction, and the convex teeth 41a become the convex portions 35 of the concave-convex fitting structure M. The spline 41 is a small tooth with a module of 0.5 or less. The module is a value obtained by dividing the pitch circle diameter by the number of teeth.

Then, as shown by cross hatching in FIG. 2, heat treatment is performed on the outer periphery of the shaft portion 12 to form a hardened layer H. In this embodiment, the spline 41 is provided on the small diameter portion 12b side of the main body portion 12a of the shaft portion 12, and the hardened layer H extends to the entire spline 41 and a part of the back face 11a of the outer joint member 5. It is. As the heat treatment, various heat treatments such as induction hardening and carburizing and quenching can be employed. Here, induction hardening is a hardening method that applies the principle of heating a conductive object by placing Joule heat in a coil through which high-frequency current flows, and generating Joule heat by electromagnetic induction. is there. In addition, carburizing and quenching is a method in which carbon is infiltrated / diffused from the surface of a low carbon material and then quenched.

The inner peripheral surface 37 of the hole portion 22 of the hub 1, that is, the inner peripheral surface of the fitting hole 22 a is not subjected to a curing process and is set to an uncured portion (unburned state). The hardness difference between the hardened layer H of the shaft portion 12 of the outer joint member 5 and the uncured portion of the hub 1 is 20 points or more in terms of HRC (Rockwell hardness C scale). If a specific example is given, the hardness of the hardened layer H shall be about 50 HRC to 65 HRC, and the hardness of an unhardened part shall be about 10 HRC to about 30 HRC.

As can be seen from FIG. 3B, the projecting direction intermediate portion of the convex portion 35 corresponds to the position of the concave surface where the concave portion is formed, that is, the inner peripheral surface 37 of the fitting hole 22a here. If expressed by the dimensional relationship of D, D1, and D2 shown in FIG. 6, D2 <D <D1. Here, D is the inner diameter of the inner peripheral surface 37 of the fitting hole 22a, D1 is the maximum outer diameter of the convex portion 35, that is, the maximum diameter of the circle connecting the vertices of the convex portion 35 which are the convex teeth 41a of the spline 41 (circumscribed circle) Diameter), D2 is the outer diameter of the outer peripheral surface of the shaft portion between the convex portions, that is, the maximum diameter of a circle connecting the bottoms of the concave teeth 41b of the spline 41. D3 is the inner diameter of the large-diameter hole 46 of the hole 22 and has a relationship of D1 <D3.

The structure and processing method of splines are well known (see JIS B 0006: 1993). For example, it can be formed by various processing methods such as rolling, cutting, pressing, and drawing. As the surface hardening treatment, various heat treatments such as induction hardening and carburizing and quenching can be employed.

Then, as shown in FIG. 6, with the shaft center of the hub 1 and the shaft center of the outer joint member 5 aligned, the shaft portion 12 of the outer joint member 5 is inserted into the hole 22 of the hub 1, The shaft portion 12 is press-fitted into the perfect circular fitting hole 22 a of the hub 1. At this time, since the large diameter portion 46 of the hole 22 is larger than the maximum outer diameter of the convex portion 35 (D1 <D3) as described above, the shaft portion 12 can be easily inserted. Furthermore, the taper part 49a plays a role of guiding the tip of the shaft part 12, and the shaft part 12 can be press-fitted into the fitting hole 22a without causing a shift. In addition, when the taper part 49a is not provided, centering when the shaft part 12 of the outer joint member 5 is press-fitted into the fitting hole 22a of the hub 1 cannot be performed. There is a risk of problems such as tilting. The angle θ of the tapered portion 49a is preferably 15 ° to 75 ° as described above. If the angle is less than 15 °, the guide function can be exhibited, but the axial dimension of the taper portion 49a becomes longer, and not only the time required for press-fitting is increased, but also the total length of the hub 1 may be increased. On the other hand, if it exceeds 75 °, the guide function becomes insufficient, and there is a risk of misalignment.

The diameter D of the inner peripheral surface 37 of the fitting hole 22a, the maximum outer diameter D1 of the convex portion 35, and the minimum outer diameter D2 of the concave teeth 41b of the spline 41 are in the above relationship, and the hardness of the convex portion 35 Is 20 points or more larger than the hardness of the inner peripheral surface 37, and by pressing the shaft portion 12 into the hole 22 of the hub 1, the convex portion 35 bites into the inner peripheral surface 37 and the concave portion 36 extends along the axial direction. Will be formed. This is a kind of cutting by the spline 41.

When the shaft portion 12 is press-fitted into the fitting hole 22a of the hub 1, a curled protrusion 45 is formed as shown in FIG. The protruding portion 45 is accommodated in an accommodating portion 57 formed of an annular space formed on the outer periphery of the small diameter portion 12 b of the shaft portion 12. The protruding portion 45 is a material having a capacity corresponding to the concave portion 36 formed by inserting the convex portion 35, and is extruded from the formed concave portion 36 or cut to form the concave portion 36. Or it is comprised from both what was extruded and what was cut. In this manner, the protruding portion 45 that is a part of the material scraped off or pushed out from the inner peripheral surface of the hole portion 22 enters the storage portion 57.

In this manner, by providing the storage portion 57 that stores the protruding portion 45 generated by the formation of the concave portion by press-fitting, the protruding portion 45 can be held (maintained) in the storage portion 57, and the protruding portion 45 is a vehicle outside the apparatus. There is no intrusion. That is, the protruding portion 45 can be kept stored in the storage portion 57, and it is not necessary to perform the removal process of the protruding portion 45, the number of assembling operations can be reduced, and the assembling workability can be improved. Cost reduction can be achieved.

When the end surface 52 of the shaft portion 12 hits the receiving surface 53 of the inner wall 22c of the hub 1, the press-fitting is completed. In this state, as shown in FIGS. 3A and 3B, the entire fitting contact portion 38 between the convex portion 35 at the end of the shaft portion 12 and the concave portion 36 fitted thereto is in close contact. . In other words, the shape of the convex portion 35 is transferred to the mating concave portion forming surface (in this case, the inner peripheral surface 37 of the fitting hole 22a of the hub 1). At this time, the convex portion 35 bites into the inner peripheral surface 37 of the fitting hole 22a, so that the hole portion 22 is slightly expanded in diameter, and the axial movement of the convex portion 35 is allowed. When the movement in the direction stops, the hole 22 is reduced in diameter to return to the original diameter. In other words, the hub 1 is elastically deformed in the radial direction when the convex portion 35 is press-fitted, and a preload corresponding to the elastic deformation is applied to the tooth surface of the convex portion 35 (surface of the concave portion fitting portion). For this reason, the concave / convex fitting structure M in which the entire concave portion fitting portion of the convex portion 35 is in close contact with the corresponding concave portion 36 can be reliably formed. That is, a female spline 42 that is in close contact with the male spline 41 is formed on the inner peripheral surface of the hole 22 of the hub 1 by the spline (male spline) 41 on the shaft portion 12 side. In some regions of the concave-convex fitting structure M, a gap may be inevitably generated between the convex portion 35 and the concave portion 36 in the process of forming the concave portion by the convex portion 35.

In this way, the concave / convex fitting structure M is formed, and the axial position of the concave / convex fitting structure M is a position avoiding the position directly below the raceway surfaces 26, 27, 28, 29 of the rolling bearing 2, that is, This is a position that does not correspond to the radial direction with respect to the ball contact portion position of the raceway surfaces 26, 27, 28, and 29.

After completion of press-fitting, the bolt 54 is inserted into the through hole 56 of the hub 1 and screwed into the screw hole 50 of the shaft portion 12. The bolt 54 includes a flanged head portion 54a and a screw shaft portion 54b. The screw shaft portion 54b includes a large-diameter base portion 55a, a small-diameter main body portion 55b, and a tip-side screw portion 55c. As shown in FIG. 2, the base portion 55 a corresponds to the through hole 56 of the hub 1, and the screw portion 55 c corresponds to the screw hole 50 of the shaft portion 12. The inner diameter d1 of the through hole 56 is set slightly larger than the outer diameter d2 of the base portion 55a (see FIG. 6). The dimensions are managed so that the diameter difference (d1-d2) is as small as possible. Therefore, in addition to keeping the processing tolerance small, a combination (matching) of the hub 1 and the bolt 54 may be adopted. As a specific example, it is about 0.05 mm <(d1-d2) <0.5 mm. The maximum outer diameter of the screw portion 55c is set to be the same as the outer diameter d2 of the base portion 55a or slightly smaller than the outer diameter of the base portion 55a.

By tightening the bolt 54, the flange portion 60 of the head portion 54a of the bolt 54 comes into close contact with the seat surface 51 of the inner wall 22c of the hub 1, and the inner wall 22c is sandwiched between the end surface 52 of the shaft portion 12 and the head portion 54a of the bolt 54. Is done.

As already described, since the mouth portion 11 of the outer joint member 5 is not brought into contact with the end portion (in this case, the caulking portion 31) of the hub 1, the caulking portion 31 of the hub 1 and the back face 11a of the mouth portion 11 are formed. There is a clearance 58 between the two. As shown in FIG. 5, the gap 58 is preferably closed with a seal member 59. As can be seen from FIG. 2, the clearance 58 includes a portion extending in the radial direction between the caulking portion 31 of the hub 1 and the back face 11 a of the mouth portion 11, a hole portion 22 of the hub 1, and a shaft of the outer joint member 5. There is a portion extending in the axial direction between the large diameter portion 12 a of the portion 12. In this embodiment, the seal member 59 is disposed in the vicinity of the corner where the radial portion and the axial portion of the clearance 58 meet. The material, shape and the like of the seal member 59 can be arbitrarily selected. FIG. 5A shows an example of an O-ring, and FIG. 5B shows an example of a band-shaped elastic material such as a gasket.

A sealing material (not shown) may be interposed between the seat surface 60 a of the bolt 54 and the bottom surface of the counterbore 51 of the hub 1. For example, a sealing material (sealant) made of various resins that can be cured after application and can exhibit sealing properties between the seating surface 60a and the bottom surface of the spot facing 51 may be applied to the seating surface 60a of the bolt 54. In addition, as this sealing material, it is desirable to select a material that does not deteriorate in the atmosphere in which the wheel bearing device is used.

As described above, the concave-convex fitting structure M in which the entire fitting contact portion 38 between the convex portion 35 of the outer joint member 5 and the concave portion 36 of the hub 1 is in close contact can be reliably formed. Moreover, since the member in which the recess 36 is formed does not need to be splined, not only can the processing cost be reduced, but also the work efficiency is improved because the phase alignment between the splines is not required for assembly. Damage to the tooth surface during press-fitting can be avoided, and a stable fitting state can be maintained.

Further, in the concave / convex fitting structure M, since the entire fitting contact portion 38 between the convex portion 35 and the concave portion 36 is in close contact, a gap that causes play is not formed in the radial direction and the circumferential direction. For this reason, all of the fitting parts contribute to rotational torque transmission, stable torque transmission is possible, and no abnormal noise is generated.

The bolt fastening restricts the shaft 12 from coming off from the hub 1 in the axial direction, enabling stable torque transmission over a long period of time. In particular, by providing the inner wall 22c sandwiched between the end surface 52 of the shaft portion 12 of the outer joint member 5 and the head portion 54a of the bolt 54, the axial positioning is performed and the dimensional accuracy of the wheel bearing device is stabilized. At the same time, the axial length of the concave-convex fitting structure M can be secured to a stable length, and the torque transmission can be improved.

Further, since the preload is applied to the rolling bearing 2 by crimping the end portion of the hub 1 and applying the end surface of the inner ring 24, it is not necessary to apply the mouth portion 11 of the outer joint member 5 to the inner ring 24. Accordingly, since it is not necessary to pay attention to the bearing preload when the shaft portion 12 of the outer joint member 5 is press-fitted, the efficiency of the work for assembling the hub 1 and the outer joint member 5 is improved. In addition, since the hub 1 and the mouse portion 11 are not in contact with each other, the problem of abnormal noise occurring at the contact portion between the hub 1 and the mouse portion 11 is solved.

By sealing the gap 58 between the mouth portion 11 of the outer joint member 5 and the caulking portion 31 at the end of the hub 1 with the seal member 59, rainwater and foreign matter can be prevented from entering from the gap 58. In addition, it is possible to avoid the deterioration of the adhesion due to rain water, foreign matter, or the like on the uneven fitting structure M. Further, since a sealing material is interposed between the seating surface 60 a of the bolt 54 and the bottom surface of the counterbore 51, rainwater and foreign matter enter the concave-convex fitting structure M from the clearance between the bolt 54 and the through hole 56. Can be prevented and quality can be improved.

In addition, by arranging the intermediate portion in the protruding direction of the convex portion 35 on the concave portion forming surface before the concave portion is formed, the convex portion 35 bites into the concave portion forming surface during press-fitting, and the concave portion 36 is reliably formed. can do. That is, the press-fitting allowance with respect to the other side of the convex part 35 can be taken sufficiently. As a result, the formability of the concave-convex fitting structure M is stabilized, there is no variation in press-fit load, and a stable torsional strength is obtained.

In the embodiment shown in FIG. 2, the convex portion 35 of the concave-convex fitting structure M is provided on the shaft portion 12 of the outer joint member 5, and the hardness of the axial end portion of the convex portion 35 is set to the bore inner diameter portion of the hub 1. If the shaft portion 12 is press-fitted into the hole portion 22 of the hub 1, the hardness on the shaft portion side can be increased and the rigidity of the shaft portion can be improved.

By arranging the concave / convex fitting structure M so as not to be directly under the raceway surface of the rolling bearing 2, occurrence of hoop stress on the bearing raceway surface can be suppressed. As a result, it is possible to prevent bearing failures such as a decrease in rolling fatigue life, occurrence of cracks, and stress corrosion cracking, and a high-quality wheel bearing device can be provided.

The spline 41 formed on the shaft portion 12 can improve the moldability of the spline 41 and reduce the press-fit load by using small teeth with a module of 0.5 or less. In addition, since the convex part 35 can be comprised with the spline of the standard goods normally formed in this kind of shaft, this convex part 35 can be easily formed at low cost.

In the spline 41 shown in FIG. 3, the pitch of the convex teeth 41a and the pitch of the concave teeth 41b are set to be the same. Therefore, as shown in FIG. 3B, the circumferential thickness L of the projecting direction intermediate portion of the convex portion 35 and the circumferential direction at a position corresponding to the intermediate portion between the convex portions 35 adjacent in the circumferential direction. The dimension L0 is substantially the same.

On the other hand, as shown in FIG. 9, the circumferential thickness L2 of the projecting direction intermediate portion of the convex portion 35 is a circumferential dimension at a position corresponding to the intermediate portion between the convex portions 35 adjacent in the circumferential direction. It may be smaller than L1. That is, in the spline 41 formed in the shaft portion 12, a portion that is a convex on the hub 1 side that fits between the convex portions 35 in the circumferential thickness (tooth thickness) L2 of the intermediate portion in the protruding direction of the convex portion 35. 43 is made smaller than the circumferential thickness (tooth thickness) L1 of the intermediate portion in the protruding direction.

Therefore, the total tooth thickness Σ (B1 + B2 + B3 +...) Of the convex portion 35 on the entire circumference on the shaft portion 12 side is replaced by the total tooth thickness Σ (A1 + A2 + A3 +) of the convex portion 43 (convex tooth) on the hub 1 side. ...) is set smaller than. Thereby, the shear area of the convex portion 43 on the hub 1 side can be increased, and the torsional strength can be ensured. And since the tooth thickness of the convex part 35 is small, a press-fit load can be made small and a press-fit property can be aimed at. When making the sum of the circumferential thicknesses of the convex portions 35 smaller than the sum of the circumferential thicknesses of the convex portions 43 on the other side, the circumferential thickness L2 of all the convex portions 35 is adjacent to the circumferential direction. It is not necessary to make it smaller than the dimension L1 in the circumferential direction between the matching convex portions 35. That is, among the plurality of convex portions 35, even if the circumferential thickness of the arbitrary convex portion 35 is the same as the circumferential dimension between the convex portions adjacent in the circumferential direction, it is larger than the circumferential dimension. However, it is sufficient if the sum is small. In addition, the convex part 35 in FIG. 9 is made into the cross-sectional trapezoid (Mt. Fuji shape).

In the wheel bearing device described above, after the shaft portion 12 of the outer joint member 5 is press-fitted into the fitting hole 22a of the hub 1, the end surface 52 of the small diameter portion 12b of the shaft portion 12 is brought into contact with the end surface 53 of the inner wall 22c. As a result, the hub 1 and the outer joint member 5 are positioned in the axial direction. Therefore, a gap 58 is formed between the caulking portion 31 of the hub 1 and the back face 11a of the mouth portion 11. On the other hand, the axial direction positioning of the hub 1 and the outer joint member 5 can be performed by bringing the caulking portion 31 of the hub 1 and the back surface 11a of the mouth portion 11 into contact with each other after press-fitting. In that case, the end surface 52 of the small diameter portion 12b of the shaft portion 12 does not contact the end surface 53 of the inner wall 22c, and a gap is formed between them. When the caulking portion 31 is brought into contact with the end surface 52 of the small diameter portion 12b as described above, the contact surface pressure between the caulking portion 31 of the hub 1 and the back surface 11a of the mouse portion 11 is preferably 100 MPa or less. If the contact surface pressure exceeds 100 MPa, there is a difference in the amount of twist between the outer joint member 5 and the hub 1 at the time of a large torque load, and this difference may cause a sudden slip at the contact portion and generate noise. It is. By setting the contact surface pressure to 100 MPa or less, it is possible to provide a quiet wheel bearing device by preventing the generation of abnormal noise.

If the bolt 54 is removed from the state shown in FIG. 2, the hub 1 and the outer joint member 5 can be separated. That is, the fitting force of the concave-convex fitting structure M allows the outer joint member 5 to be pulled out from the hub 1 by applying a pulling force that is equal to or greater than a predetermined force.

For example, the hub 1 and the constant velocity universal joint 3 can be separated using a jig 70 as shown in FIG. The jig 70 includes a base 71, a pressing bolt member 73 inserted into a screw hole 72 penetrating the base 71, and a screw shaft 76 inserted into the screw hole 50 of the shaft portion 12. The base 71 is provided with through holes 74 at the same pitch as the hub bolts 33 of the hub 1, and the base 71 can be attached to the hub 1 by tightening nuts 75 through the hub bolts 33 in the through holes 74.

After attaching the base 71 to the hub 1 or before attaching the base 71, the screw shaft 76 is inserted into the screw hole 50 of the shaft portion 12, and the base portion 76a projects from the inner wall 22c of the hub 1 to the anti-joint side. . The protruding amount of the base portion 76a is set longer than the axial dimension of the uneven fitting structure M.

Thereafter, when the pressing bolt member 73 is passed through the screw hole 72 of the base 71 and the tip is abutted against the tip of the screw shaft 76, the screw shaft 76 and the pressing bolt member 73 are coaxial as shown in FIG. And it becomes coaxial with the said wheel bearing apparatus. In this state, the pressing bolt member 73 is turned and moved toward the screw shaft 76 as indicated by the white arrow. As a result, the pressing bolt member 73 pushes the screw shaft 76, the screw shaft 76 pushes the outer joint member 5, and the outer joint member 5 moves in the direction of the white arrow and comes out of the hub 1. Thereafter, the base 71 is removed from the hub 1, and the screw shaft 76 is removed from the shaft portion 12.

The hub 1 and the outer joint member 5 once separated in this way can be assembled again. That is, as shown in FIG. 8, the shaft portion 12 of the outer joint member 5 is inserted into the hole portion 22 of the hub 1, and the male spline 41 of the shaft portion 12 and the female spline 42 of the hub 1 formed by the previous press-fitting. Match the phase with. Then, the bolt 54 is inserted from the through hole 56 of the hub 1 and screwed into the screw hole 50 of the shaft portion 12 of the outer joint member 5.

When the bolt 54 is turned from this state, the shaft portion 12 is drawn and enters the fitting hole 22a of the hub 1. At this time, when the hole 22 is slightly expanded in diameter, allowing the axial portion 12 to enter in the axial direction and stopping the axial movement, the hole 22 contracts to return to the original diameter. Will be diameter. As a result, as in the previous press-fitting, the concave-convex fitting structure M in which the entire concave portion fitting portion of the convex portion 35 is in close contact with the corresponding concave portion 36 can be reliably configured.

When the shaft 54 is pulled by turning the bolt 54, the base 55a of the bolt 54 is in a state corresponding to the through hole 56 as shown in FIG. As described above, the inner diameter d1 of the through hole 56 is set to be slightly larger than the outer diameter d2 of the base portion 55a of the shaft portion 54b, and the diameter difference (d1-d2) is kept as small as possible. The through hole 56 exhibits a guide function with respect to the bolt 54, and the shaft portion 12 of the outer joint member 5 can be press-fitted into the fitting hole 22a of the hub 1 without causing misalignment. In addition, regarding the axial dimension of the through-hole 56, if it is too short, a stable guide function cannot be exhibited. Conversely, if it is too long, the inner wall 22c becomes thick, and the axial length of the uneven fitting structure M is secured accordingly. In addition, the hub 1 is heavy. Therefore, various changes can be made in consideration of these.

In addition, since the taper part 50a expanded toward the opening side is provided in the end surface side of the screw hole 50 of the shaft part 12, there exists an advantage that the screw shaft 76 and the volt | bolt 54 can be easily put in the screw hole 50.

Further, as shown in FIG. 1, the hole 22 of the hub 1 has an inner diameter larger than the convex outer diameter D1 (see FIG. 6) of the shaft portion 12 of the outer joint member 5, and has unevenness in the circumferential direction. You may make it provide the formed large diameter part 22d. The large diameter portion 22d is located on the opposite side of the inner wall 22c across the fitting hole 22a, in other words, on the press-fitting start side of the fitting hole 22a, and is used when the shaft portion 12 is re-pressed into the fitting hole 22a. Acts as a guide groove. That is, when reassembling after separation, it becomes easy to press-fit the convex portion into the concave portion formed last time, and the stability of reassembly can be improved without causing misalignment or inclination.

Incidentally, in the first press-fitting (press-fitting in which the concave portion 36 is formed on the inner peripheral surface 37 of the hole 22), the press-fitting load is relatively large, and thus it is necessary to use equipment such as a press machine for press-fitting. On the other hand, since the press-fitting load is smaller than the first press-fitting, the press-fitting can be performed stably and accurately without using a press machine or the like. For this reason, it is possible to separate and reassemble the hub 1 and the outer joint member 5 even at a site where there is no such mechanical equipment.

As described above, since the outer joint member 5 can be removed from the hole 22 of the hub 1 by applying an axial pulling force to the shaft portion 12 of the outer joint member 5, work for repair and inspection of each part is performed. (Maintenability) can be improved. Moreover, by fitting the shaft portion 12 of the outer joint member 5 into the hole portion 22 of the hub 1 again after the repair and inspection of each part, the entire fitting contact portion 38 between the convex portion 35 and the concave portion 36 is in close contact. The combined structure M can be configured. For this reason, the wheel bearing device capable of stable torque transmission can be configured again.

In the above description, the pressing bolt member 73 is screwed with the tip end of the screw shaft 76 reaching the bottom of the screw hole 50 and the base end portion of the screw shaft 76 protruding from the inner wall 22c to the outboard side. Thus, the hub 1 and the outer joint member 5 are separated. The tip of the screw shaft 76 reaches the bottom of the screw hole 50. If there is a gap, the female screw 72 and the screw hole 50 may have the same thread direction. This is because as the member 73 is screwed, the screw shaft 76 rotates together and no pressing force can be applied.

FIG. 11 shows an example in which a bolt 54 for fastening the hub 1 and the outer joint member 5 is used in place of the screw shaft 76. In this case, the direction of the screw thread between the screw hole 50 of the shaft portion 12 and the female screw 72 of the base 71 is the reverse direction. That is, if the screw hole 50 is a right-hand screw (a screw that advances when turned clockwise), the female screw 72 is a left-hand screw (a screw that advances when the screw hole 50 rotates counterclockwise). Is a right-hand thread.

After the base 71 is attached to the hub 1 in this way or before the base 71 is attached, the bolt 54 screwed into the screw hole 50 of the shaft portion 12 is screwed out so that the head 54a of the bolt 54 is attached to the inner wall. Project from 22c to the outboard side. The protruding amount of the bolt member 54 is set longer than the axial length of the concave-convex fitting structure M.

Thereafter, as shown in FIG. 11, the pressing bolt member 73 is screwed into the screw hole 72 of the base 71 from the outboard side, and in this state, is screwed toward the screw shaft 76 side as indicated by an arrow. At this time, since the bolt 54 and the pressing bolt member 73 are arranged on the same axis (on the axis of the wheel bearing device), the screw bolt 73 becomes a bolt by this screwing. 54 is pressed in the direction of the arrow. As a result, a separating force is generated on the bolt 54, the outer joint member 5 moves in the arrow direction with respect to the hub 1, and the outer joint member 5 is detached from the hub 1.

In this configuration, even when the pressing bolt member 73 is screwed, the bolt 54 does not rotate together, and a pressing force can be stably applied to the bolt 54. Therefore, it is possible to apply a pressing force to the bolt without bringing the tip of the bolt 54 into contact with the bottom surface of the screw hole 50, and the bolt 54 that couples the hub wheel 1 and the outer joint member 5 is used at the time of separation. It can be used as it is as a bolt, and the separation workability can be improved and the cost can be reduced. The bolt 54 for fastening the hub wheel 1 and the outer joint member 5 may be different from the separating bolt.

In the above description, the spline 41 constituting the convex portion 35 is formed on the shaft portion 12 side, the surface hardening treatment is applied to the spline 41 of the shaft portion 12, and the inner peripheral surface of the hub 1 is uncured (raw material). Yes. On the other hand, as shown in FIG. 10, spline 61 (convex teeth 61 a and concave teeth 61 b) subjected to surface hardening treatment is formed on the inner peripheral surface of the hole portion 22 of the hub 1, and the shaft portion 12 has a surface. You may not give a hardening process. The spline 61 can also be formed by various processing methods such as broaching, cutting, pressing, and drawing. As the surface hardening treatment, various heat treatments such as induction hardening and carburizing and quenching can be employed.

In this case, the intermediate portion in the protruding direction of the convex portion 35 corresponds to the position of the concave portion forming surface (the outer peripheral surface of the shaft portion 12) before the concave portion is formed. That is, the diameter dimension (minimum diameter dimension of the convex portion 35) D4 connecting the vertices of the convex portions 35 that are the convex teeth 61a of the spline 61 is smaller than the outer diameter size D6 of the shaft portion 12, and the concave teeth of the spline 61 The diameter dimension of the circle connecting the bottoms of 61b (the inner diameter dimension of the inner peripheral surface of the fitting hole between the convex portions) D5 is set larger than the outer diameter dimension D6 of the shaft portion 12. That is, a relationship of D4 <D6 <D5 is established.

If the shaft portion 12 is press-fitted into the hole portion 22 of the hub 1, the convex portion 35 on the hub 1 side can form a concave portion 36 into which the convex portion 35 is fitted on the outer peripheral surface of the shaft portion 12. Thereby, the whole fitting contact part 38 of the convex part 35 and the recessed part fitted to this closely_contact | adheres.

Here, the fitting contact portion 38 is a range B shown in FIG. 10B, and is a range from the middle of the mountain shape to the top of the mountain in the cross section of the convex portion 35. Further, a gap 62 is formed on the outer diameter side of the outer peripheral surface of the shaft portion 12 between the adjacent convex portions 35 in the circumferential direction.

Even in this case, since the protruding portion 45 is formed by press-fitting, it is preferable to provide a storage portion 57 for storing the protruding portion 45 (see FIG. 4). Since the protruding portion 45 is formed on the mouse side of the shaft portion 12, the storage portion is provided on the hub 1 side.

Thus, the convex portion 35 of the concave-convex fitting structure M is provided on the inner peripheral surface 37 of the hole portion 22 of the hub 1, and the hardness of the axial end portion of the convex portion 35 is set to the outside of the shaft portion 12 of the outer joint member 5. In the case of press-fitting with a diameter higher than that of the diameter portion, it is not necessary to perform surface hardening treatment (heat treatment) on the shaft portion side, so that the productivity of the outer joint member 5 of the constant velocity universal joint is excellent.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made. For example, as the cross-sectional shape of the convex portion 35 of the concave-convex fitting structure M, FIG. 3 shows an example of a triangular shape, and FIG. 9 shows an example of a trapezoid (Mt. Fuji shape). It can be arbitrarily selected from various shapes such as a shape and a rectangular shape, and the area, number, circumferential pitch, and the like of the convex portions 35 can be arbitrarily changed. That is, it is not necessary to form the spline 41 and the convex tooth 41a of the spline 41 to be the convex portion 35 of the concave-convex fitting structure M, and it may be a key, and a curved corrugated mating surface May be formed. In short, the convex portion 35 disposed along the axial direction can be press-fitted into the mating side, and the concave portion 36 can be formed on the mating side with the convex portion 35 so as to closely fit the convex portion 35. It is only necessary that the entire fitting contact portion 38 between the portion 35 and the concave portion fitted thereto is in close contact, and that rotational torque can be transmitted between the hub 1 and the constant velocity universal joint 3.

The hole portion 22 of the hub 1 may be a deformed hole such as a polygonal hole other than a circular hole, and the cross-sectional shape of the end of the shaft portion 12 fitted to the hole 22 is also a polygon other than a circular cross section. It may be an irregular cross section.

Furthermore, when the shaft portion 12 is press-fitted into the hub 1, only the press-fitting start end portion of the convex portion 35 needs to be harder than the portion where the concave portion 36 is formed. There is no. FIG. 3 shows an example in which the gap 40 is formed, but the gap 40 between the convex portions 35 may be bitten into the inner peripheral surface 37 of the hub 1.

Note that the hardness difference between the convex portion 35 side and the concave portion forming surface side formed by the convex portion 35 is preferably 20 points or more in HRC, but 20 points if the convex portion 35 can be press-fitted. It may be less.

Although the end surface of the convex portion 35, that is, the press-fitting start end is an example of a plane perpendicular to the axis (see FIG. 4), it may be an inclined surface having a predetermined angle with respect to the axis. In this case, it may be inclined from the inner diameter side toward the outer diameter side toward the anti-convex portion side or inclined toward the convex portion side.

Furthermore, you may provide the small recessed part arrange | positioned by the predetermined pitch along the circumferential direction in the internal peripheral surface 37 of the hole 22 of the hub 1. FIG. The small recess needs to be smaller than the volume of the recess 36. By providing such a small recess, the press-fit property of the protrusion 35 can be improved. That is, by providing the small concave portion, the capacity of the protruding portion 45 formed when the convex portion 35 is press-fitted can be reduced, and the press-fit resistance can be reduced. Moreover, since the protrusion part 45 can be decreased, the volume of the storage part 57 can be reduced, and the workability of the storage part 57 and the strength of the shaft part 12 can be improved. Various shapes such as a semi-elliptical shape and a rectangular shape can be adopted as the shape of the small concave portion, and the number can be arbitrarily set.

Regarding the bearing type of the rolling bearing 2, an example of a double row angular contact ball bearing using balls as the rolling elements 30 is shown, but a double row tapered roller bearing using rollers (rollers) may be used.

Further, although the case of the third generation wheel bearing device has been described as an example, the first generation, the second generation, or the fourth generation may be used.

When press-fitting the convex portion 35, as described above, the side where the concave portion 36 is formed may be fixed and the side having the convex portion 35 may be moved, or conversely, the convex portion 35 is provided. The side where the recess 36 is formed may be moved, or both may be moved.

In the constant velocity universal joint 3, the inner joint member 6 and the shaft 10 may be integrated via the concave / convex fitting structure M described here.

As described above, the seating surface of the bolt 54 is a sealing material interposed between the seating surface 60a of the bolt 54 that fixes the bolt between the hub 1 and the shaft portion 12 and the bottom surface of the counterbore 51 formed on the inner wall 22c. Instead of or in addition to applying the resin to the 60a side, the resin may be applied to the bottom surface of the spot facing 51. In addition, if the bolt 54 is tightened and the seat surface 60a of the bolt 54 and the bottom surface of the counterbore 51 have excellent adhesion, such a sealing material can be omitted. That is, by grinding the bottom surface of the counterbore 51, the adhesion of the bolt 54 to the seat surface 60a can be improved. Of course, the sealing material can be omitted if the adhesion can be exhibited even in a so-called turning finish state without grinding the bottom surface of the spot facing 51.

It is a longitudinal cross-sectional view of the hub and rolling bearing for demonstrating this invention. It is a longitudinal cross-sectional view of the wheel bearing apparatus which shows 1st Embodiment of this invention. FIG. 3 is an enlarged cross-sectional view of an uneven fitting structure in the wheel bearing device of FIG. 2. It is the X section enlarged view of Drawing 3 (a). FIG. 3 is a partially enlarged view of FIG. 2. It is the elements on larger scale of the wheel bearing apparatus of FIG. 2 using an O-ring. It is the elements on larger scale of the wheel bearing apparatus of FIG. 2 which used the gasket. FIG. 3 is an exploded longitudinal sectional view showing a state before press-fitting of the wheel bearing device of FIG. 2. It is a longitudinal cross-sectional view which shows the isolation | separation process of the wheel bearing apparatus of FIG. It is a longitudinal cross-sectional view which shows the reassembly process of the wheel bearing apparatus of FIG. It is sectional drawing which shows the modification of an uneven | corrugated fitting structure. It is a cross-sectional view of the uneven | corrugated fitting structure which shows 2nd Embodiment of this invention. It is the Y section enlarged view of Drawing 10 (a). It is a longitudinal cross-sectional view which shows the other example of the isolation | separation process of the wheel bearing apparatus of FIG. It is a longitudinal cross-sectional view of the conventional wheel bearing apparatus.

DESCRIPTION OF SYMBOLS 1 Hub 2 Bearing 3 Constant velocity universal joint 11 Mouse | mouth part 12 Shaft part 22 Hole part 22c Inner wall 24 Inner ring 31 Caulking part 35 Convex part 36 Concave contact part 45 Projection part 50 Screw hole 52 End surface 54 Bolt 54a Head part 57 Storage Part 58 clearance 59 seal member 60a bearing surface

Claims

An inner member having an outer member having a double row outer race on the inner periphery, a hub provided with a flange for attaching a wheel, and an inner member having a double row inner race facing the outer race, and the outer race and inner facing each other Provided with a plurality of rolling elements arranged between the race and a constant velocity universal joint having an outer joint member, and provided with a hole in the hub for fitting with a shaft portion of the outer joint member of the constant velocity universal joint. Wheel bearing device,
A convex portion extending in the axial direction provided on one of the inner peripheral surface of the hub and the outer peripheral surface of the shaft portion of the outer joint member is press-fitted into the other along the axial direction, and is projected on the other side by the convex portion. By forming a recess that fits tightly into the part, forming a concave-convex fitting structure in which the entire fitting contact portion between the convex part and the concave part is in close contact, and fastening the hub and the shaft part of the outer joint member with a bolt The hub and the outer joint member can be separated and reassembled, and the hub is provided with a through hole for opening the hole and through which the bolt is inserted, and the through hole is formed with respect to the hole of the hub. A wheel bearing device having a coaxiality of 1.0 mm or less.
The wheel bearing device according to claim 1, wherein an inner wall having the through hole is provided in the hub, and a seating surface for the bolt is formed on the opposite side of the inner wall of the hub from the hole.
The wheel bearing device according to claim 2, wherein a receiving surface that contacts the tip of the shaft portion of the outer joint member is formed on the hole side of the inner wall of the hub.
A convex portion of the concave-convex fitting structure is provided at the shaft portion of the outer joint member, and at least the hardness of the axial end portion of the convex portion is made higher than the inner diameter portion of the hole portion of the hub, and the shaft portion is By press-fitting into the hole from the axial end side of the convex portion, a concave portion that closely fits to the convex portion is formed on the inner peripheral surface of the hole portion of the hub at the convex portion, thereby forming the concave-convex fitting structure. The wheel bearing device according to any one of claims 1 to 3.
5. The inner member is composed of a hub and an inner ring each having a row of inner races, and the inner ring is fitted to the hub and the ends of the hub are caulked to fix them together. The wheel bearing apparatus of any one of Claims.
A storage portion for storing the protruding portion that is generated when the concave portion is formed by the press-fitting is provided on the outer diameter side of the shaft portion on the opposite joint side than the concave-convex fitting structure, and the storage portion is provided on the shaft portion of the outer joint member. The wheel bearing device according to any one of claims 1 to 5, wherein the wheel bearing device is formed by a small-diameter step portion formed at a tip and a hub, and an inner diameter of the through hole of the hub is smaller than an outer diameter of the small-diameter step portion.
The wheel bearing device according to any one of claims 1 to 6, wherein the concave-convex fitting structure is disposed at a position avoiding a position directly below the raceway surface of the rolling bearing.
A screw hole is provided in the axial center portion of the shaft portion of the outer joint member along the axial direction. When the hub and the shaft portion of the outer joint member are separated from each other, a pressing force in the axial direction is applied to the bolt screwed into the screw hole. The wheel bearing device according to any one of claims 1 to 7, wherein a separation force is generated in the outer joint member by applying