JP2010120406A - Bearing device for wheel and axle module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing device for a wheel and an axle module capable of reducing circumferential play, preventing entering of foreign matter (mud and salt water, etc.) to suppress generation of internal rust and stably transmitting torque over a long period, with excellent connecting workability between a hub ring and an outer joint member of a constant velocity universal joint. <P>SOLUTION: Axially extending ridges 35 are provided either on the outer diameter surface of a shaft part of the outer joint member or on the inner diameter surface 37 of a hole part 22 of the hub ring 1 and the ridges 35 are axially press fitted to the other. This forms, in the other, the grooves 36 to be fitted in close contact with the ridges 35 by the ridges 35, and thereby forming a ridge-groove fitting structure M in which the whole fitting and contacting area of the ridges 35 and the grooves 36 are in close contact with each other. A coating film is formed to close a gap between the inner diameter surface of the hub ring 1 and an outer diameter surface of an end part on an outboard side of the shaft part. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a wheel bearing device and an axle module.

  The present 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, and an axle module using such a wheel bearing device.

  A power transmission device that transmits engine power of a vehicle such as an automobile to a wheel transmits power from the engine to the wheel, and also causes radial or axial displacement from the wheel that occurs when the vehicle bounces or turns when traveling on rough roads. , And moment displacement must be allowed. For this reason, an axle module is used.

  The axle module is connected to the constant velocity universal joint on the outboard side (fixed constant velocity universal joint), the constant velocity universal joint on the inboard side (sliding constant velocity universal joint), and these constant velocity universal joints. A drive shaft. In this case, on the outboard side, the wheel hub, the rolling bearing, and the constant velocity universal joint are integrated to form a wheel bearing device. Note that the side closer to the outer side of the vehicle when assembled to the vehicle is referred to as the outboard side, and the side closer to the center is referred to as the inboard side.

  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 surface of the double row rolling bearing is integrally formed on the outer periphery of the hub ring integrally having a ring, and further, the constant velocity universal joint is integrated with the hub ring. 4th generation has been developed in which the other inner raceway surface of the double-row rolling bearing is integrally formed on the outer periphery of the outer joint member that constitutes.

  For example, Patent Document 1 describes what is called a third generation. As shown in FIG. 12, a wheel bearing device called a third generation includes a hub wheel 152 having a flange 151 extending in the outer diameter direction, and a constant velocity universal joint 154 to which an outer joint member 153 is fixed. And an outer member 155 disposed on the outer peripheral side of the hub wheel 152. The outer member 155 forms an outer ring of the rolling bearing.

  The constant velocity universal joint 154 is disposed between the outer joint member 153, the inner joint member 158 disposed in the mouth portion 157 of the outer joint member 153, and the inner joint member 158 and the outer joint member 153. A ball 159 to be provided and a holder 160 for holding the ball 159 are provided. Further, a spline portion 161 is formed on the inner peripheral surface of the center hole of the inner joint member 158, and an end spline portion of a shaft (not shown) is inserted into the center hole, and the spline portion 161 on the inner joint member 158 side The spline portion on the shaft side is engaged.

  The hub wheel 152 has a cylindrical portion 163 and the flange 151, and a short cylindrical shape on which an unillustrated wheel and brake rotor are mounted on the outer end surface 164 (end surface on the outboard side) of the flange 151. A pilot part 165 is provided so as to protrude. The pilot portion 165 includes a large-diameter first portion 165a and a small-diameter second portion 165b. A brake rotor is externally fitted to the first portion 165a, and a wheel is externally fitted to the second portion 165b.

  A cutout portion 166 is provided on the outer peripheral surface of the end portion of the cylinder portion 163 on the mouth portion 157 side, and the inner ring 167 is fitted into the cutout portion 166. A first inner raceway surface 168 is provided in the vicinity of the flange on the outer peripheral surface of the cylindrical portion 163 of the hub ring 152, and a second inner raceway surface 169 is provided on the outer peripheral surface of the inner ring 167. A bolt mounting hole 162 is provided in the flange 151 of the hub wheel 152, and a hub bolt for fixing the wheel and the brake rotor to the flange 151 is mounted in the bolt mounting hole 162.

  The outer member 155 is provided with two rows of outer raceways 170 and 171 on its inner periphery, and a flange (vehicle body mounting flange) 182 on its outer periphery. Then, the first outer raceway surface 170 of the outer member 155 and the first inner raceway surface 168 of the hub ring 152 face each other, and the second outer raceway surface 171 of the outer member 155 and the raceway surface 169 of the inner ring 167 are opposed to each other. Opposed and a rolling element 172 is interposed between them.

  The shaft portion 173 of the outer joint member 153 is inserted into the tube portion 163 of the hub wheel 152. The shaft portion 173 has a screw portion 174 formed at the end on the side opposite to the mouse portion, and a spline portion 175 is formed between the screw portion 174 and the mouse portion 157. In addition, a spline portion 176 is formed on the inner peripheral surface (inner diameter surface) of the cylindrical portion 163 of the hub wheel 152, and when the shaft portion 173 is inserted into the cylindrical portion 163 of the hub wheel 152, The spline portion 175 engages with the spline portion 176 on the hub wheel 152 side.

Then, the nut member 177 is screwed to the screw portion 174 of the shaft portion 173 protruding from the tube portion 163, and the hub wheel 152 and the outer joint member 153 are connected. At this time, the inner end surface (back surface) 178 of the nut member 177 and the outer end surface 179 of the cylindrical portion 163 are in contact with each other, and the end surface 180 on the shaft portion side of the mouse portion 157 and the outer end surface 181 of the inner ring 167 are in contact with each other. That is, by tightening the nut member 177, the hub wheel 152 is sandwiched between the nut member 177 and the mouth portion 157 via the inner ring 167.
JP 2004340403 A

  Thus, in the wheel bearing device, the spline portion 175 on the shaft portion 173 side and the spline portion 176 on the hub wheel 152 side are engaged. For this reason, it is necessary to perform spline processing on both the shaft portion 173 side and the hub wheel 152 side, which increases the cost, and at the time of press-fitting, the spline portion 175 on the shaft portion 173 side and the spline portion 176 on the hub wheel 152 side. It is necessary to match the unevenness of the teeth. At this time, if the teeth are pressed 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. As described above, when there is a backlash in the circumferential direction, the transmission performance of the rotational torque is inferior and abnormal noise may occur. For this reason, it has been difficult to establish both the damage to the concavo-convex teeth and the play in the circumferential direction in the case of spline fitting as in the prior art.

  Further, it is necessary to screw the nut member 177 to the screw portion 174 of the shaft portion 173 protruding from the cylindrical portion 163. For this reason, it has a screw fastening operation at the time of assembly, which is inferior in workability, has a large number of parts, and inferior in part manageability.

  By the way, when rainwater or the like enters the spline fitting portion, rust or the like may be generated and damaged in the spline fitting portion, and there is a problem in durability.

  In view of the above problems, the present invention can suppress circumferential backlash and is excellent in connection workability between the hub wheel and the outer joint member of the constant velocity universal joint. Etc.), a wheel bearing device and an axle module that can suppress the occurrence of internal rust and can stably transmit torque over a long period of time are provided.

  A wheel bearing device of the present invention includes a bearing having a plurality of rows of rolling elements arranged between opposing outer races and inner races, a hub wheel attached to the wheel, and a constant velocity universal joint, A bearing device for a wheel in which a shaft portion of an outer joint member of a constant velocity universal joint that is inserted into a hole of the wheel is integrated with a hub wheel via a concave-convex fitting structure, and the shaft portion of the outer joint member and the hub wheel A convex portion extending in the axial direction provided in one of the hole portions is press-fitted into the other, and a concave portion that closely fits to the convex portion is formed on the other by the convex portion. Constructs a concave-convex fitting structure in which the entire fitting contact portion with the concave portion is in close contact, and forms a coating film that closes at least the gap between the inner diameter surface of the hub wheel and the outer diameter surface of the end portion on the outboard side of the shaft portion It is a thing.

  According to the wheel bearing device of the present invention, the concave-convex fitting structure includes a convex portion provided on one of the outer diameter surface of the shaft portion of the outer joint member and the inner diameter surface of the hole portion of the hub wheel, Since the entire fitting contact portion with the other concave portion fitted to the convex portion is in close contact, a gap in which play occurs in the radial direction and the circumferential direction is not formed in this fitting structure.

  A convex portion extending in the axial direction provided on one of the outer diameter surface of the shaft portion of the outer joint member and the inner diameter surface of the hole portion of the hub wheel is press-fitted into the other along the axial direction, and is projected to the other. A concave portion that closely fits to the convex portion is formed at the portion to constitute the concave-convex fitting structure. In other words, the shape of the convex portion is transferred to the concave portion forming surface on the other side.

  A convex portion of the concave-convex fitting structure is provided on the shaft portion of the outer joint member of the constant velocity universal joint, and at least the hardness of the axial end portion of the convex portion is higher than the inner diameter portion of the hole portion of the hub wheel, By pressing the shaft portion into the hole portion of the hub wheel from the axial end portion side of the convex portion, a concave portion that closely fits the convex portion is formed on the inner diameter surface of the hole portion of the hub wheel at the convex portion. You may comprise an uneven | corrugated fitting structure. At this time, the convex portion bites into the concave portion forming surface (the inner diameter surface of the hole portion of the hub wheel), so that the hole portion is slightly expanded in diameter, and the convex portion is allowed to move in the axial direction. However, if the movement in the axial direction stops, the diameter of the hole portion is reduced 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.

  Further, a convex portion of the concave-convex fitting structure is provided on the inner diameter surface of the hole portion of the hub wheel, and at least the hardness of the axial end portion of the convex portion is set to the outer diameter portion of the shaft portion of the outer joint member of the constant velocity universal joint. The convex portion on the hub wheel side is press-fitted into the shaft portion of the outer joint member from the axial end portion side, thereby projecting to the outer diameter surface of the shaft portion of the outer joint member. The concave-convex fitting structure may be formed by forming a concave portion that closely fits to the portion. If the convex portion bites into the outer diameter surface of the shaft portion, the hole portion is slightly expanded in diameter, allowing the convex portion to move in the axial direction and stopping the axial movement. The part is reduced in diameter to return to the original diameter. As a result, the entire fitting contact region between the convex portion and the concave portion (outer diameter surface of the shaft) of the mating member fitted into the convex portion is brought into close contact.

  Since a coating film is formed to close the gap between the inner diameter surface of the hub wheel and the outer diameter surface of the end of the shaft on the outboard side, rainwater and foreign matter from the hub wheel outboard side to the uneven fitting structure Can be prevented, and the inner surface of the hub wheel and the end of the shaft can be prevented from corroding.

  An end portion of the shaft portion of the outer joint member is formed with an enlarged caulking portion that engages with the inner diameter surface of the hub wheel, and the coating film is at least the inner diameter surface of the hub wheel and the outer diameter caulking portion of the outer joint member. The gap between the outer diameter surfaces of the two may be closed.

  The coating film may be provided in a range extending from the shaft end surface of the shaft portion of the outer joint member to the entire inner diameter surface of the hub wheel on the outboard side from the shaft end surface.

  A short cylindrical wheel pilot is provided on the outboard side of the hub wheel, and the coating film has a shaft end surface of the shaft portion of the outer joint member, the entire inner diameter surface of the hub wheel on the outboard side from the shaft end surface, and the wheel pilot. It may be provided in a range up to the outer diameter surface.

  The coating film can be formed by an electrodeposition coating method. Here, the electrodeposition coating means that the coating film forming component is negatively or positively charged when a metal object is immersed in a paint bath filled with a water-soluble paint and a direct current voltage is applied to the object as an anode or a cathode. And electrodeposited on the surface of the object to be coated. In this way, a coating film is formed. The case where the article is used as the anode is called anion electrodeposition, and the case where it is used as the cathode is called cation electrodeposition. Compared to other coating methods, electrodeposition coating can provide a uniform film thickness even with complex shapes, so it can be coated with high anticorrosion properties, and the film thickness can be managed. In addition, there is very little paint loss, and there are significant advantages in terms of hygiene and pollution control.

  Cationic electrodeposition is carried out with the object to be coated as the cathode and the coating film components charged positively. In this case, since metal ions do not dissolve into the paint bath, the corrosion resistance is particularly excellent. That is, the coating film becomes an anticorrosive film by cationic electrodeposition coating. For this reason, it is preferable to use cationic electrodeposition coating for electrodeposition coating in the present invention, but of course, anion electrodeposition coating may also be used.

  It is preferable that a zinc phosphate film or a galvanized film is formed as a base treatment for the paint film (anticorrosive film). Moreover, it is preferable that the film thickness of a coating film is set to the range of 10-50 micrometers.

  The axle module of the present invention includes the wheel bearing device described above, and includes a drive shaft connected to the constant velocity universal joint on the outboard side, and a sliding type on the inboard side connected to the other of the drive shafts. A constant velocity universal joint is provided.

  In the wheel bearing device of the present invention, in the fitting structure, there is no gap in which play occurs in the radial direction and the circumferential direction, so that all of the fitting parts contribute to rotational torque transmission and stable torque transmission is possible. In addition, no abnormal noise is generated. Furthermore, since the contact is made without a gap, the strength of the torque transmitting portion is improved. For this reason, the bearing unit for drive wheels can be made lightweight and compact.

  By pressing a convex portion extending in the axial direction provided on one of the outer diameter surface of the shaft portion of the outer joint member and the inner diameter surface of the hole portion of the hub wheel into the other along the axial direction, A concave portion closely fitting to the convex portion can be formed by the convex portion. For this reason, an uneven | corrugated fitting structure can be formed reliably. Moreover, it is not necessary to form a spline portion or the like on the member where the recess is formed, and it is excellent in productivity and does not require the phase alignment between the splines. Damage to the tooth surface can be avoided and a stable fitting state can be maintained.

  Moreover, while providing the convex part of the concave-convex fitting structure on the shaft part of the outer joint member of the constant velocity universal joint, the hardness of the axial end of the convex part is higher than the inner diameter part of the hole of the hub wheel, If the shaft portion is press-fitted into the hole of the hub wheel from the axial end portion side of the convex portion, the hardness on the shaft portion side can be increased and the rigidity of the shaft portion can be improved. In addition, a convex portion of the concave-convex fitting structure is provided on the inner diameter surface of the hole portion of the hub wheel, and the hardness of the axial end portion of the convex portion is determined from the outer diameter portion of the shaft portion of the outer joint member of the constant velocity universal joint. In the case where the convex portion on the hub wheel side is press-fitted into the shaft portion of the outer joint member from the end portion in the axial direction, there is no need to perform hardness treatment (heat treatment) on the shaft portion side, so that the constant velocity Excellent productivity of universal joint outer joint members.

  The paint film prevents rainwater and foreign matter from entering the concave-convex fitting structure from the outboard side of the hub wheel. Thereby, generation | occurrence | production of the rust of an uneven | corrugated fitting structure can be suppressed, and the stable torque transmission over a long term is attained. On the other hand, if a coating film is not provided, rainwater and foreign matter infiltrate into the concave / convex fitting structure, and the shaft member from the hub wheel is caused by thinning, cracking, stress corrosion cracking, etc. There is a concern that omissions may occur. Here, stress corrosion cracking refers to a phenomenon in which when an alloy metal is exposed to a specific corrosive environment under a static tensile stress within an allowable stress, the alloy is cracked with corrosion. That is, corrosion accelerated by stress is collectively referred to as stress corrosion. The force applied to an object is called stress (stress), and it is classified into three types: tensile / compressive stress and torsional stress. Of these, the stress corrosion affects the tensile stress, and the compression stress does not accelerate the corrosion. Stress applied to an object is classified into internal stress and external stress applied from the outside. For this reason, stress corrosion cracking is defined as “brittle fracture of metal caused by the joint action of stress and corrosion”. Brittle failure is a failure that occurs suddenly before it appears to be almost deformed. Used separately from ductile fracture.

  If a coating film is formed by electrodeposition coating, “even with complex shapes, a uniform film thickness can be obtained, so coating with high anti-corrosion properties can be performed, and film thickness management is also available. It has a great advantage in terms of pollution control. ” In addition, it is not necessary to form a seal structure using a separate member such as a seal plate, and it is possible to reduce the number of parts and cost such as processing costs. In particular, it is preferable to use a cationic electrodeposition coating having excellent anticorrosion properties.

  If the zinc phosphate treatment is performed as the base treatment of the paint film, the surface of the steel material that becomes the material is roughened by a chemical reaction due to this zinc phosphate treatment, which improves the bite of the paint and improves the adhesion. To do. Moreover, the film thickness of the coating film is obtained by adding the film thickness of zinc phosphate as the base treatment and the film thickness of the cationic electrodeposition coating. In this case, it is preferable to set the thickness of the coating film 81 in the range of 10 to 50 μm. When the film thickness is as thin as less than 10 μm, the function as the anticorrosive film layer cannot be sufficiently exhibited. Cationic electrodeposition coating has the property that it loses its conductivity as the coating is electrodeposited, preventing the formation of a coating film exceeding a certain level. Therefore, there is an upper limit to the coating film thickness, which is 50 μm.

  If a galvanizing treatment is performed as a base treatment of the coating film, the galvanizing treatment has an effect of suppressing corrosion of the material by dissolving zinc by a self-sacrificing action. For this reason, compared with a zinc phosphate process, it is excellent in corrosion resistance and rust prevention performance.

  The axle module of the present invention includes the wheel bearing device described above, and is a product that exhibits a stable function over a long period of time.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. FIG. 1 shows a first embodiment of an axle module according to the present invention. The axle module includes a constant velocity universal joint T1 on the outboard side, a constant velocity universal joint T2 on the inboard side, and a drive shaft 10 connected to the constant velocity universal joints T1 and T2. In this case, on the outboard side, the hub wheel 1, the double row rolling bearing (bearing structure portion) 2, and the constant velocity universal joint T1 (3) are integrated to constitute a wheel bearing device. The side that is outside the vehicle when assembled in a vehicle such as an automobile is the outboard side (left side of the drawing), and the side that is inside the vehicle when assembled in a vehicle such as an automobile is called the inboard side (right side of the drawing). . In this case, the shaft portion 12 of the outer joint member of the constant velocity universal joint 3 to be inserted into the hole portion 22 of the hub wheel 1 and the hub wheel 1 are coupled via the concave / convex fitting structure M.

  As shown in FIG. 2, the constant velocity universal joint T <b> 1 is interposed between the outer ring 5 as an outer joint member, the inner ring 6 as an inner joint member disposed inside the outer ring 5, and the outer ring 5 and the inner ring 6. Thus, a plurality of balls 7 that transmit torque and a cage 8 that is interposed between the outer ring 5 and the inner ring 6 and holds the balls 7 are configured as main members. The inner ring 6 is spline-fitted by press-fitting the end 10a of the drive shaft 10 into the hole inner diameter 6a and is coupled to the drive shaft 10 so as to be able to transmit torque. A retaining ring 9 for retaining the drive shaft is fitted to the end 10a of the drive shaft 10.

  The outer ring 5 is composed of a mouse part 11 and a stem part (shaft part) 12. The mouse part 11 has a bowl shape opened at one end, and a plurality of track grooves 14 extending in the axial direction are circumferentially formed on the inner spherical surface 13 thereof. It is formed at equal intervals in the direction. The track groove 14 extends to the open end of the mouse portion 11. In the inner ring 6, a plurality of track grooves 16 extending in the axial direction are formed on the outer spherical surface 15 at equal intervals in the circumferential direction.

  The track groove 14 of the outer ring 5 and the track groove 16 of the inner ring 6 make a pair, and one ball 7 as a torque transmitting element can roll on each ball track constituted by the pair of track grooves 14 and 16. It is incorporated. The ball 7 is interposed between the track groove 14 of the outer ring 5 and the track groove 16 of the inner ring 6 to transmit torque. The cage 8 is slidably interposed between the outer ring 5 and the inner ring 6, contacts the inner spherical surface 13 of the outer ring 5 at the outer spherical surface, and contacts the outer spherical surface 15 of the inner ring 6 at the inner spherical surface. The constant velocity universal joint in this case is a Zepper type, but may be another constant velocity universal joint such as an undercut free type having a straight straight portion at the bottom of the track groove.

  Further, the opening of the mouse part 11 is closed by a boot 17. The boot 17 includes a large diameter portion 17a, a small diameter portion 17b, and a bellows portion 17c that connects the large diameter portion 17a and the small diameter portion 17b. The large-diameter portion 17a is externally fitted to the opening of the mouse portion 11, and is fastened by the boot band 18a in this state, and the small-diameter portion 17b is externally fitted to the boot mounting portion 10b of the drive shaft 10, and in this state, the boot band 18b It is concluded at.

  As shown in FIG. 1, the constant velocity universal joint T2 on the inboard side includes an outer joint member 131, a tripod member 132 as an inner joint member, and a roller 133 as a torque transmission member as main components.

  The outer joint member 131 includes a mouth portion 131a and a stem portion 131b that are integrally formed. The mouse portion 131a has a cup shape opened at one end, and a track groove 136 extending in the axial direction is formed at a position of the inner circumference in the circumferential direction.

  The tripod member 132 includes a boss 138 and a leg shaft 139. The boss 138 is formed with a spline hole 138a that is coupled to the end spline 10c of the drive shaft 10 so that torque can be transmitted. The leg shaft 139 protrudes in the radial direction from the circumferentially divided position of the boss 138. Each leg shaft 139 of the tripod member 132 carries a roller 133.

  The opening of the outer joint member 131 is closed with a boot 140. The boot 140 includes a large-diameter portion 140a, a small-diameter portion 140b, and a bellows portion 140c between the large-diameter portion 140a and the small-diameter portion 140b, and is formed on the outer peripheral surface on the opening side of the mouse portion 131a via the boot band 141a. The large-diameter portion 140a of the boot 140 is fixed, and the small-diameter portion 140b of the boot 140 is fixed to the outer peripheral surface of the boot mounting portion 10d of the drive shaft 10 via a boot band 141b.

  As shown in FIG. 2, the hub wheel 1 includes a cylindrical portion 20 and a flange 21 provided at an end portion of the cylindrical portion 20 on the outboard side. The hole portion 22 of the cylindrical portion 20 includes a shaft portion fitting hole 22a in the middle portion in the axial direction, a conical hole 22b on the outboard side, and a large diameter hole 22c on the inboard side. That is, the shaft portion 12 of the outer ring 5 of the constant velocity universal joint T1 and the hub wheel 1 are coupled to each other through the concave-convex fitting structure M described later in the shaft portion fitting hole 22a. A tapered portion (tapered hole) 22d is provided between the shaft portion fitting hole 22a and the large diameter hole 22c. The tapered portion 22d is reduced in diameter along the press-fitting direction when the hub wheel 1 and the shaft portion 12 of the outer ring 5 are coupled. The taper angle θ1 (see FIG. 5) of the taper portion 22d is, for example, 15 ° to 75 °.

  A short cylindrical pilot portion 90 is provided on the end face of the hub wheel 1 on the outboard side. The pilot section 90 includes a short cylindrical brake pilot 91 on the inboard side and a wheel pilot 92 on the outboard side having a smaller diameter than the brake pilot 91.

  The rolling bearing 2 straddles the inner member 19 having an inner ring 24 fitted to a small diameter step portion 23 provided on the inboard side of the cylindrical portion 20 of the hub wheel 1, and the cylindrical portion 20 to the inner ring 24 of the hub wheel 1. And an outer member 25 that is externally fitted. The outer member 25 is provided with two rows of outer raceways (outer races) 26 and 27 on its inner circumference, and a first inner raceway (inner race) provided on the outer circumference of the shaft portion of the first outer raceway 26 and the hub wheel 1. Race) 28 is opposed to the second outer raceway surface 27 and a second inner raceway surface (inner race) 29 provided on the outer peripheral surface of the inner ring 24, and a ball as the rolling element 30 is interposed therebetween. Intervened. That is, an inner member having inner races 28 and 29 with a part of the hub wheel 1 (outer diameter surface of the cylindrical portion 20) and the inner ring 24 press-fitted into the outer periphery of the end portion of the hub wheel 1 on the inboard side. 19 is constituted. Seal members S1 and S2 are attached to both openings of the outer member 25.

  In this case, the end portion on the inboard side of the hub wheel 1 can be crimped and the inner ring 24 can be pressed by the crimping portion 31, and a preload is applied to the rolling bearing 2. As a result, the inner ring 24 can be fastened to the hub wheel 1. The flange 21 of the hub wheel 1 is provided with a bolt mounting hole 32, and a hub bolt 33 for fixing the wheel and the brake rotor to the flange 21 is mounted in the bolt mounting hole 32. The caulking portion 31 is formed by swing caulking. The swing caulking is a method in which the central axis of the punch (caulking jig) is plastically deformed while being swung around the central axis of the hub wheel 1.

  As shown in FIGS. 2 and 3, the concave-convex fitting structure M includes, for example, a convex portion 35 provided in the shaft portion 12 and extending in the axial direction, and an inner diameter surface of the hole portion 22 of the hub wheel 1 (in this case, the shaft The inner surface 37) of the part fitting hole 22a is formed with a concave part 36, and the entire fitting contact part 38 of the convex part 35 and the concave part 36 of the hub wheel 1 fitted to the convex part 35 is in close contact. Yes. That is, a plurality of convex portions 35 are arranged at a predetermined pitch along the circumferential direction on the outer peripheral surface of the shaft portion 12 on the side opposite to the mouse portion, and the inner diameter surface of the shaft portion fitting hole 22a of the hole portion 22 of the hub wheel 1 A plurality of concave portions 36 into which the convex portions 35 are fitted to 37 are formed along the circumferential direction. That is, the convex part 35 and the concave part 36 fitted to this are tight-fitted over the entire circumference in the circumferential direction.

  In this case, each convex portion 35 has a triangular shape (mountain shape) having a convex rounded apex in cross section, and the fitting contact portion (recessed fitting portion) 38 of each convex portion 35 is shown in FIG. It is the range A shown in b), which is the range from the mid-section of the mountain in the cross section to the summit. Further, a gap 40 is formed on the inner diameter side with respect to the inner diameter surface 37 of the hub wheel 1 between the adjacent convex portions 35 in the circumferential direction.

  In this way, the hub wheel 1 and the shaft portion 12 of the outer ring 5 of the constant velocity universal joint 3 can be connected via the concave-convex fitting structure M. At this time, as described above, the end portion on the inboard side of the hub wheel 1 is swaged and preload is applied to the rolling bearing 2 by the swaged portion 31, so that the mouth portion 11 of the outer ring 5 is applied to the mouth portion 11. Therefore, it is not necessary to apply a preload to the inner ring 24. In this embodiment, the end face of the constant velocity universal joint, that is, the back surface 11a of the mouse part 11 and the crimping part (swinging caulking part) 31 of the hub wheel 1 are in contact with each other. A gap may be provided between the back surface 11 a of the portion 11 and the caulking portion (swing caulking portion) 31 of the hub wheel 1.

  By the way, when assembling this wheel bearing device, the concave portion 36 is formed by the convex portion 35 by press-fitting the shaft portion 12 of the outer ring 5 into the hub wheel 1 as will be described later. If press-fitting is performed at this time, the material protrudes from the concave portion 36 formed by the convex portion 35 to form a protruding portion 45 (see FIG. 4). The protruding portion 45 is the material of the capacity of the concave portion 36 into which the concave portion fitting portion of the convex portion 35 is inserted (fitted), and is extruded from the concave portion 36 to be formed, and is cut to form the concave portion 36. Or both extruded and cut. For this reason, in the wheel bearing device shown in FIG. 1 and the like, the shaft portion 12 is provided with a pocket portion (accommodating portion) 50 for accommodating the protruding portion 45. By providing a circumferential groove 51 at the shaft end edge of the spline 41 of the shaft portion 12, a pocket portion (storage portion) 50 is formed.

  Further, in this wheel bearing device, as shown by a one-dot chain line in FIG. 2, a coating film 81 that closes a gap between the inner diameter surface of the hub wheel 1 and the outer diameter surface of the end portion on the outboard side of the shaft portion 12 is provided. Forming. That is, the recessed portion 95 is provided on the end surface of the shaft portion 12, thereby forming an annular flange 96 at the end portion of the shaft portion 12. A coating film 81 is formed from the end surface 96a of the flange portion 96, that is, from the shaft end surface of the shaft portion 12 to the endboard side inner diameter surface 97 (see FIG. 4) of the fitting hole 22a from the end surface 96a. .

  The coating film 81 is formed by, for example, electrodeposition coating. Here, the electrodeposition coating means that the coating film forming component is negatively or positively charged when a metal object is immersed in a paint bath filled with a water-soluble paint and a direct current voltage is applied to the object as an anode or a cathode. And electrodeposited on the surface of the object to be coated. In this way, a coating film is formed. The case where the article is used as the anode is called anion electrodeposition, and the case where it is used as the cathode is called cation electrodeposition. Compared to other coating methods, electrodeposition coating can provide a uniform film thickness even with complex shapes, so it can be coated with high anticorrosion properties, and the film thickness can be managed. In addition, there is very little paint loss, and there are significant advantages in terms of hygiene and pollution control.

  Cationic electrodeposition is carried out with the object to be coated as the cathode and the coating film components charged positively. In this case, since metal ions do not dissolve into the paint bath, the corrosion resistance is particularly excellent. That is, the coating film becomes an anticorrosive film by cationic electrodeposition coating. For this reason, it is preferable to use cationic electrodeposition coating for electrodeposition coating in the present invention, but of course, anion electrodeposition coating may also be used.

Thus, when cationic electrodeposition coating is performed, the coating film 81 becomes an anticorrosive film. For this reason, a zinc-based film is formed as a base treatment for the anticorrosive film in order to improve the anticorrosion and to improve the adhesion between the object to be coated and the paint.

  The zinc-based coating is subjected to zinc phosphate treatment. Since the surface of the steel material as a raw material is roughened by a chemical reaction by this zinc phosphate treatment, the bite of the paint is improved and the adhesion is improved. The film thickness of the coating film 81 is obtained by adding the film thickness of zinc phosphate as the base treatment and the film thickness of the cationic electrodeposition coating. In this case, it is preferable to set the thickness of the coating film 81 in the range of 10 to 50 μm. When the film thickness is as thin as less than 10 μm, the function as the anticorrosive film layer cannot be sufficiently exhibited. Cationic electrodeposition coating has the property that it loses its conductivity as the coating is electrodeposited, preventing the formation of a coating film exceeding a certain level. Therefore, there is an upper limit to the coating film thickness, which is 50 μm.

  Cationic electrodeposition coating requires a baking step after electrodeposition of the paint, and the baking condition is preferably about 140 to 160 ° C. for about 20 minutes (material temperature holding condition).

  A galvanizing treatment may be performed as a base treatment for the cationic electrodeposition coating. The galvanizing treatment has an effect of suppressing corrosion of the material by dissolving zinc by a self-sacrificing action, and therefore has excellent corrosion resistance and rust prevention performance compared to the zinc phosphate treatment.

  Next, the fitting method of the uneven fitting structure M will be described. In this case, as shown in FIG. 5, the outer diameter portion of the shaft portion 12 is subjected to a thermosetting process, and a spline 41 including a convex portion 41 a and a concave portion 41 b along the axial direction is formed on the cured layer H. For this reason, the convex part 41a of the spline 41 is cured, and the convex part 41a becomes the convex part 35 of the concave-convex fitting structure M. The range of the hardened layer H in this embodiment is from the outer end edge of the spline 41 to a part of the bottom wall of the mouth portion 11 of the outer ring 5 as shown by the cross hatched portion. As this thermosetting 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. Further, a hardened layer H1 is formed on the outer diameter side of the hub wheel 1 by induction hardening, and the inner diameter side of the hub wheel 1 is left unfired. The range of the hardened layer H1 in this embodiment is from the base portion of the flange 21 to the vicinity of the caulking portion of the small-diameter step portion 23 into which the inner ring 24 is fitted, as shown by the cross-hatched portion.

  If induction hardening is performed, the surface is hard and the inside can be kept as it is, so that the inner diameter side of the hub wheel 1 can be kept unfired. For this reason, it is set as the non-hardened part (unbaked state) which does not perform a thermosetting process in the inner diameter surface 37 side of the hole 22 of the hub wheel 1. The hardness difference between the hardened layer H of the shaft portion 12 of the outer ring 5 and the uncured portion of the hub wheel 1 is 20 points or more in HRC. Specifically, the hardness of the hardened layer H is set to about 50 HRC to 65 HRC, and the hardness of the uncured portion is set to about 10 HRC to about 30 HRC.

  At this time, the intermediate portion in the protruding direction of the convex portion 35 corresponds to the position of the concave portion forming surface (in this case, the inner diameter surface 37 of the hole portion 22 of the hub wheel 1) before the concave portion is formed. That is, as shown in FIG. 5, the inner diameter dimension D of the inner diameter surface 37 of the hole portion 22 is the maximum outer diameter of the convex portion 35, that is, the diameter of a circle connecting the vertices of the convex portion 35 that is the convex portion 41 a of the spline 41. It is smaller than the dimension (circumscribed circle diameter) D1 and is set larger than the outer diameter dimension of the shaft outer diameter surface between the convex parts, that is, the diameter dimension D2 of the circle connecting the bottoms of the concave parts 41b of the spline 41. That is, D2 <D <D1.

  The spline 41 can be formed by various processing methods such as rolling processing, cutting processing, press processing, and drawing processing, which are known publicly known means. Moreover, various heat processing, such as induction hardening and carburizing hardening, can be employ | adopted as a thermosetting process.

  The outer diameter D4 of the flange portion 96 is set to be slightly smaller than the inner diameter dimension D of the fitting hole 22a of the hole portion 22. That is, as will be described later, the flange portion 96 serves as an alignment member when the hub wheel 1 of the shaft portion 12 is slightly press-fitted into the hole portion 22.

  Then, as shown in FIG. 5, the shaft portion 12 of the outer ring 5 is inserted into the hub wheel 1 with the shaft center of the hub wheel 1 aligned with the shaft center of the outer ring 5 of the constant velocity universal joint T1 ( Press fit). At this time, since the tapered portion 22d having a reduced diameter along the press-fitting direction is formed in the hole portion 22 of the hub wheel 1, the tapered portion 22d can constitute a guide at the start of press-fitting. Further, the diameter D of the inner diameter surface 37 of the hole 22, the maximum outer diameter D1 of the convex portion 35, and the diameter D2 of the bottom of the concave portion 41b of the spline 41 are as described above. Since the hardness of the portion 35 is 20 points or more larger than the hardness of the inner diameter surface 37 of the hole portion 22, if the shaft portion 12 is press-fitted into the hole portion 22 of the hub wheel 1, the convex portion 35 bites into the inner diameter surface 37. Thus, the convex portion 35 forms the concave portion 36 into which the convex portion 35 is fitted along the axial direction.

  By being press-fitted in this manner, as shown in FIG. 4, the formed protruding portion 45 is housed in the pocket portion 50 while curling. That is, a part of the material scraped off or pushed out from the inner diameter surface of the hole portion 22 enters the pocket portion 50.

  Further, as shown in FIG. 3, 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 therein is brought into close contact with the press fitting. That is, the shape of the convex portion 35 is transferred to the concave portion forming surface on the other side (in this case, the inner diameter surface 37 of the hole portion 22). At this time, the convex portion 35 bites into the inner diameter surface 37 of the hole portion 22, so that the hole portion 22 is slightly expanded in diameter, and the convex portion 35 is allowed to move in the axial direction. When the movement stops, the hole 22 is reduced in diameter to return to the original diameter. In other words, the hub wheel 1 is elastically deformed in the radial direction when the convex portion 35 is press-fitted, and a preload corresponding to this 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.

  By the way, when the shaft portion 12 of the outer ring 5 is press-fitted into the hole portion 22 of the hub wheel 1, a step surface G is provided on the outer diameter surface of the mouth portion 11 of the outer ring 5 as shown in FIG. The jig K may be engaged with the step surface G, and a press-fitting load (axial load) may be applied from the press-fitting jig K to the step surface G. The stepped surface G may be provided on the entire circumference in the circumferential direction or at a predetermined pitch along the circumferential direction. For this reason, the press-fitting jig K to be used only needs to be able to apply an axial load corresponding to these stepped surfaces G.

  After the press-fitting, the coating film 81 is formed on the inner surface 97 on the outboard side of the fitting hole 22 a of the hub wheel 1 and the end surface of the shaft portion 12. The coating film 81 can be formed by electrodeposition coating as described above.

  By the way, in the axle module of the present invention assembled in FIG. 1, the outer member 25 of the rolling bearing 2 is assembled in the knuckle 34 (see FIG. 10) on the vehicle body side. That is, the vehicle body mounting flange 25a is provided on the outer diameter surface of the outer member 25, and the inboard side of the vehicle body mounting flange 25a is a fitting portion 25b that is attached to the knuckle 34.

  In this case, the outer diameter dimension D11 of the fitting portion 25b of the outer member 25 is larger than the maximum outer diameter dimension D12 of the constant velocity universal joint T1. Here, the maximum outer diameter dimension D12 of the constant velocity universal joint T1 means the maximum outer diameter dimension of the constant velocity universal joint T1 in a state including accessories such as the boot 17 and the boot bands 18a and 18b.

  Further, as shown in FIG. 1, the maximum outer diameter D13 of the inboard side constant velocity universal joint T2 is set to be smaller than the outer diameter D11 of the fitting portion 25b of the outer member 25. The maximum outer diameter D13 of the inboard side constant velocity universal joint T2 is the same as that of the outboard side constant velocity universal joint T1, and the inboard side in a state including accessories such as the boot 140 and the boot band 141. It means the maximum outer diameter dimension of the quick universal joint T2.

  The axle module assembled in this way is assembled to the vehicle by inserting the axle module into the knuckle 34 from the sliding constant velocity universal joint T2 side on the inboard side, and the outside of the wheel bearing device on the outboard side. The member 25 is attached to the inner diameter surface of the knuckle 34. Then, the bolt member is screwed into the screw hole provided in the flange 25a of the outer member 25, whereby the knuckle 34 and the outer member 25 are integrated. That is, the axle module of the present invention can be assembled to the vehicle in an assembled state.

  The axle module according to the present invention can be assembled to a vehicle in an assembled state. Thereby, the work man-hour at the assembly work site can be reduced, and workability is enhanced. In this case, it is not necessary to turn the knuckle 34 as in the conventional process, so that the work space is minimized. Moreover, it is possible to stabilize the quality by preventing damage to parts during disassembly / assembly.

  Further, on the wheel bearing device side, the concave / convex fitting structure M is in close contact with the entire fitting contact portion 38 between the convex portion 35 and the concave portion 36. There is no gap formed in the circumferential direction. For this reason, all the fitting parts contribute to rotational torque transmission, stable torque transmission is possible, and no abnormal noise is generated.

The member (in this case, the hub wheel 1) in which the concave portion 36 is formed does not need to have a spline portion or the like formed therein, is excellent in productivity, and does not require phase alignment between the splines, thereby improving assemblability. In addition, it is possible to avoid damage to the tooth surface during press-fitting and maintain a stable fitting state. In addition, since the convex part 35 can be comprised with the spline normally formed in this kind of drive shaft, this convex part 35 can be easily formed at low cost.

  Since the tapered portion 22d can form a guide at the start of press-fitting, the shaft portion 12 of the outer ring 5 can be pressed into the hole portion 22 of the hub wheel 1 without causing a deviation, and a stable torque can be obtained. Communication is possible. Further, since the outer diameter D4 of the flange portion 96 is set slightly smaller than the inner diameter dimension D of the fitting hole 22a of the hole portion 22, it becomes an alignment member, and the shaft portion is used as a hub wheel while preventing misalignment. It is possible to press-fit, and more stable press-fitting is possible.

  In particular, in the present invention, the coating film 81 can block the opening on the outboard side of the hub wheel 1, so that rainwater and foreign matter enter the concave-convex fitting structure M from the outboard side of the hub wheel 1. Can be prevented. Thereby, generation | occurrence | production of the rust of the uneven | corrugated fitting structure M can be suppressed, and stable torque transmission is attained over a long period of time. In addition, as in this embodiment, if the coating film 81 is formed by cationic electrodeposition coating, a corrosion-preventing film having excellent corrosion resistance and rust prevention performance is obtained. In addition, in the case where the zinc phosphate treatment is performed as the ground treatment for the cationic electrodeposition coating, the adhesion of the paint is improved and the peeling of the coating film 81 can be effectively prevented.

  On the other hand, if the coating film 81 is not provided, rainwater and foreign matter enter the uneven fitting structure M, and the shaft portion 12 is caused by thinning, cracking, stress corrosion cracking, etc. of the uneven fitting structure M. There is a concern that the hub wheel 1 may come off. Here, stress corrosion cracking refers to a phenomenon in which when an alloy metal is exposed to a specific corrosive environment under a static tensile stress within an allowable stress, the alloy is cracked with corrosion.

  The hardness of the axial end of the convex portion of the shaft portion 12 of the outer ring 5 of the constant velocity universal joint T1 is made higher than the inner diameter portion of the hole portion of the hub wheel 1 so that the shaft portion 12 protrudes into the hole portion 22 of the hub wheel 1. Since it press-fits from the axial direction edge part side of the part 35, the recessed part formation to the hole inner diameter surface of the hub ring 1 becomes easy. Further, the hardness on the shaft portion side can be increased, and the torsional strength of the shaft portion 12 can be improved.

  Further, since the end portion of the hub wheel 1 is crimped and preload is applied to the rolling bearing 2, it is not necessary to apply preload by the mouth portion 11 of the outer ring 5. For this reason, it is possible to press-fit the shaft portion 12 of the outer ring 5 without considering the preload of the rolling bearing 2 and to improve the connectivity (assembly property) between the hub wheel 1 and the outer ring 5.

  In addition, by providing a gap between the back surface 11a of the mouse part 11 and the caulking part (swinging caulking part) 31 of the hub wheel 1, if the mouse part 11 is not in contact with the hub wheel 1, Generation of abnormal noise due to contact between the mouse portion 11 and the hub wheel 1 can be prevented.

  On the other hand, in the said embodiment, the mouse | mouth part 11 and the crimping part 31 of the hub wheel 1 contact. Thus, when the caulking part 31 of the hub wheel 1 and the back surface 11a of the mouse part 11 are brought into contact with each other, it is desirable that the contact surface pressure between them is 100 MPa or less. If the contact surface pressure exceeds 100 MPa, there will be a difference in the torsional amount between the joint outer ring 5 and the hub wheel 1 when a large torque is applied, and this difference may cause a sudden slip at the contact portion and generate noise. It is. Therefore, by setting the contact surface pressure to 100 MPa or less, it is possible to provide a quiet wheel bearing device that prevents the generation of abnormal noise.

  Further, when the concave portion 36 is formed by press-fitting the shaft portion 12 into the hub wheel 1, work hardening occurs on the concave portion 36 side. Here, work hardening means that when plastic deformation (plastic processing) is applied to an object, the resistance to deformation increases as the degree of deformation increases, and it becomes harder than a material that has not undergone deformation. For this reason, by plastically deforming at the time of press-fitting, the inner diameter surface 37 of the hub wheel 1 on the concave portion 36 side is hardened, and the rotational torque transmission performance can be improved.

  The inner diameter side of the hub wheel 1 is relatively soft. For this reason, it is possible to improve the fitting property (adhesion) when the convex portion 35 on the outer diameter surface of the shaft portion 12 of the outer ring 5 is fitted into the concave portion 36 on the inner diameter surface of the hole portion of the hub wheel 1. It is possible to accurately suppress the occurrence of play in the radial direction and the circumferential direction.

  By providing the pocket portion 50 for accommodating the protruding portion 45 generated by forming the concave portion by press-fitting, the protruding portion 45 can be held (maintained) in the pocket portion 50, and the protruding portion 45 can be placed inside the vehicle outside the apparatus. There is no intrusion. That is, the protruding portion 45 can be kept stored in the pocket portion 50, 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.

  In the spline 41 shown in FIG. 3, the pitch of the convex portions 41a and the pitch of the concave portions 41b are set to be the same. For this reason, in the said embodiment, as shown in FIG.3 (b), it corresponds to the circumferential direction thickness L of the protrusion direction intermediate part of the convex part 35, and the said intermediate part between the convex parts 35 adjacent to the circumferential direction. The circumferential dimension L0 at the position is substantially the same.

  On the other hand, as shown in FIG. 6A, the circumferential thickness L2 of the projecting direction intermediate portion of the convex portion 35 is set at a position corresponding to the intermediate portion between the convex portions 43 adjacent in the circumferential direction. It may be smaller than the circumferential dimension L1. That is, in the spline 41 formed on the shaft portion 12, the circumferential thickness (tooth thickness) L <b> 2 of the intermediate portion in the projecting direction of the convex portion 35 is set to the height of the convex portion 43 on the hub wheel 1 side fitted between the convex portions 35. It 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 12 side is replaced by the total tooth thickness Σ (A1 + A2 + A3 +) of the convex portion 43 (convex tooth) on the hub wheel 1 side.・ It is set smaller than. As a result, the shear area of the convex portion 43 on the hub wheel 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 total of the circumferential thickness of the convex part 35 smaller than the sum total of the circumferential direction thickness in the other convex part 43, the circumferential direction thickness L2 of all the convex parts 35 is the convex part adjacent to the circumferential direction. It is not necessary to make it smaller than the circumferential dimension L1 between 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.

  6A has a trapezoidal cross section (Mt. Fuji shape), but may have an involute tooth shape as shown in FIG. 6B.

  Next, FIG. 7 shows a second embodiment of the wheel bearing device. In this case, the shaft portion retaining structure M1 is provided between the end portion of the shaft portion 12 of the outer ring 5 and the inner diameter surface of the hub wheel 1. ing. The shaft portion retaining structure M1 includes a diameter-enlarged caulking portion (tapered locking piece) 65 that extends from the end portion of the shaft portion 12 of the outer ring 5 to the outboard side and engages with the cone-shaped hole 22b. That is, the diameter-enlarged caulking portion 65 is formed of a ring-shaped body that increases in diameter from the inboard side toward the outboard side, and at least a part of the outer peripheral surface 65a is in pressure contact with or in contact with the cone-shaped hole 22b.

  In this case, a short cylindrical portion 66 is provided at the end of the shaft portion 12 of the outer ring 5, and after the shaft portion 12 is press-fitted into the hub wheel 1, the tip end portion of the short cylindrical portion 66 is expanded, thereby FIG. A tapered locking piece 65 as shown can be formed.

  The short cylindrical portion 66 is expanded in diameter using a jig 67 as indicated by a virtual line. The jig 67 includes a columnar main body 68 and a truncated cone 69 connected to the tip of the main body 68. The frustoconical portion 69 of the jig 67 has an inclined surface 69a whose inclination angle is substantially the same as that of the cone-shaped hole 22b, and whose outer diameter at the tip is the same as or slightly shorter than the inner diameter of the short cylindrical portion. The dimension is set smaller than the inner diameter of the cylindrical portion. Then, a load in the direction of the arrow α is applied by fitting the truncated cone part 69 of the jig 67 through the cone-shaped hole 22b, whereby the short cylindrical part 66 is expanded on the inner diameter side of the short cylindrical part 66. The diameter expansion force in the arrow β direction is applied. At this time, at least a part of the short cylindrical portion 66 is pressed to the inner surface of the cone-shaped hole 22b by the truncated cone portion 69 of the jig 67, and is brought into pressure contact or contact with the inner surface of the cone-shaped hole 22b. The shaft portion retaining structure M1 can be configured. In addition, when applying the load in the arrow α direction of the jig 67, it is necessary to fix the wheel bearing device so that it does not move in the arrow α direction. It is sufficient to receive a part of this by a fixing member. By the way, the inner diameter surface 66a of the short cylindrical portion 66 may have a tapered shape that expands toward the shaft end side. If it is set as such a shape, it is also possible to shape | mold an internal diameter surface by forging, and it leads to a cost reduction.

  Further, in order to reduce the load of the jig 67 in the direction of the arrow α, the short cylindrical portion 66 may be notched, and the conical surface of the truncated cone portion 69 of the jig 67 is partially arranged in the circumferential direction. Things can be used. When the short cylindrical portion 66 is notched, the short cylindrical portion 66 can be easily expanded in diameter. Further, in the case where the conical surface of the truncated cone part 69 of the jig 67 is partially arranged in the circumferential direction, a part where the diameter of the short cylindrical part 66 is enlarged becomes a part on the circumference. The indentation load can be reduced.

  After forming the concave-convex fitting structure M and the shaft portion retaining structure M1, the coating film 81 is formed along the end surface on the outboard side of the tapered locking piece 65 or the inner diameter surface 66a of the short cylindrical portion 66. Become. This coating film 81 can be formed by electrodeposition coating as described above, and a coating film having high anticorrosion properties can be formed by applying cationic electrodeposition coating on the base treatment of the zinc-based film. .

  FIG. 8 shows a third embodiment of the wheel bearing device as a coating film straddling the bottom surface 66b of the short cylindrical portion 66, the inner diameter surface 66a of the short cylindrical portion 66, the cone-shaped hole 22b, and the inner diameter surface 90a of the pilot portion 90. 81 is formed. Further, FIG. 9 shows a fourth embodiment of the wheel bearing device in which the coating film 81 is formed over the outer end surface 92b and the outer diameter surface 92a of the wheel pilot 92.

  The other structure of the wheel bearing device shown in FIGS. 8 and 9 is the same as that of the wheel bearing device shown in FIG. 2, and therefore the same structure is given the same reference numeral as that shown in FIG. The description thereof will be omitted.

  For this reason, even if it is a wheel bearing apparatus shown in FIG.8 and FIG.9, there exists an effect similar to the wheel bearing apparatus shown in FIG. Further, since the shaft portion retaining structure M1 is provided, it is possible to effectively prevent the shaft portion 12 of the outer ring 5 from coming off from the hole portion 22 of the hub wheel 1 (particularly, the shaft portion on the shaft side). As a result, a stable connected state can be maintained, and the quality of the wheel bearing device can be improved. Further, since the shaft portion retaining structure M1 is the enlarged diameter crimping portion 65, conventional screw fastening can be omitted. For this reason, it is not necessary to form the screw part which protrudes from the hole part 22 of the hub wheel 1 in the axial part 12, and while achieving weight reduction, a screw fastening operation | work can be abbreviate | omitted and aiming at the improvement of assembly workability | operativity. be able to. Moreover, in the diameter-enlarged caulking portion 65, a part of the shaft portion 12 of the outer ring 5 may be enlarged in diameter, and the shaft-portion retaining structure M1 can be easily formed.

  As described above, if the shaft portion retaining structure M1 including the enlarged diameter crimping portion 65 is provided, the constant velocity universal joint T1 can be prevented from coming off from the hub wheel 1, but the coating film 81 must be provided. For example, if it is used over a long period of time, there is a possibility that corrosion of the enlarged diameter caulking portion 65 may occur. However, in the present invention, by forming the coating film 81, corrosion of the shaft portion retaining structure M1 can be prevented. Although it is possible to protect against foreign material intrusion by using a sealing material such as a sealing plate made of another member instead of the coating film 81, in such a case, it leads to an increase in costs such as parts cost and processing cost. .

  By the way, in each said embodiment, although it has the flange 25a as the outer member 25 of the rolling bearing 2, as shown in FIG. 10, you may not have the flange 25a. In this case, the outer peripheral surface of the outer member 25 becomes the press-fitting surface 101, and the outer member 25 is press-fitted into the inner diameter surface 34 a of the knuckle 34. The outer diameter dimension D15 of the press-fitting surface 101 of the outer member 25 is made larger than the maximum outer diameter dimension D12 of the constant velocity universal joint T1.

  Further, the outer diameter D15 of the press-fitting surface 101 of the outer member 25 is set to be slightly larger than the inner diameter D16 of the inner diameter surface 34a of the knuckle 34. In other words, the relative axial and circumferential shift between the knuckle 34 and the outer member 25 is regulated by the tightening allowance between the outer circumferential surface of the outer member 25 and the knuckle inner diameter surface 34a.

  In this case, a retaining ring 85 may be interposed between the press-fitting surface (outer peripheral surface) 101 of the outer member 25 and the inner diameter surface 34 a of the knuckle 34. By using the retaining ring 85, the effect of preventing the outer member 25 and the knuckle 34 from coming off is enhanced. That is, an engagement groove (not shown) is formed on the outer peripheral surface of the outer member 25, and an engagement groove (not shown) is formed on the inner diameter surface 34 a of the knuckle 34. For this reason, the retaining ring 85 is engaged with the engagement groove on the outer peripheral surface of the outer member 25 and the engagement groove on the inner diameter surface 34 a of the knuckle 34.

  Also in this case, the outer diameter D15 of the press-fit surface 101 of the outer member 25 is larger than the maximum outer diameter dimensions D12, D13 of the constant velocity universal joints T1, T2. In the case of having the flange 25a in this way, it is necessary to set the relationship between the outer diameter D15 of the press-fitting surface 101 and the inner diameter of the inner diameter surface 34a of the knuckle 34 with higher accuracy than in the case of having no flange. There is no, and it is excellent in productivity.

  By the way, in each said embodiment, while forming the spline 41 which comprises the convex part 35 in the axial part 12 side, the hardening process is performed with respect to the spline 41 of this axial part 12, and the internal diameter surface of the hub ring 1 is unhardened. (Raw material). On the other hand, as shown in FIGS. 11 (a) and 11 (b), a spline 61 (consisting of ridges 61a and ridges 61b) in which the inner diameter surface of the hole portion 22 of the hub wheel 1 is subjected to hardening treatment is provided. While being formed, the shaft portion 12 may not be subjected to a curing process. The spline 61 can also be formed by various processing methods such as broaching, cutting, pressing, and drawing, which are publicly known means. Further, various heat treatments such as induction hardening and carburizing and quenching can be employed as the thermosetting treatment.

  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 diameter 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) D8 connecting the vertices of the convex portion 35 which is the convex portion 61a of the spline 61 is smaller than the outer diameter size D10 of the shaft portion 12, and the concave portion 61b of the spline 61 is formed. The diameter D9 of the circle connecting the bottoms of the shafts 12 is set larger than the outer diameter D10 of the shaft portion 12. That is, D8 <D10 <D9. In this case, the inner diameter surface formed by a circle connecting the bottom of the recess 61b becomes the inner diameter surface of the shaft portion fitting hole 22a of the hub wheel 1, and the convex portion 35 is a protruding portion from the bottom.

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

  Here, the fitting contact portion 38 is a range B shown in FIG. 11B, 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 for storing the protruding portion 45. Since the protruding portion 45 is formed on the mouse side of the shaft portion 12, the storage portion is provided on the hub wheel 1 side.

  In this way, in the case where the convex portion 35 of the concave-convex fitting structure M is provided on the inner diameter surface of the hole portion 22 of the hub wheel 1 and press-fitted, it is not necessary to perform the hardening treatment (heat treatment) on the shaft portion side, so that the constant velocity is achieved. There is an advantage that the productivity of the outer ring 5 of the universal joint T1 is excellent.

As described above, the embodiment of the present invention has been described. However, the present invention is not limited to the above-described embodiment, and various modifications are possible. For example, as the shape of the convex portion 35 of the concave-convex fitting structure M, FIG. In the embodiment shown in Fig. 3, the cross section is triangular, and in the embodiment shown in Fig. 6 (a), the cross section is trapezoidal (mountain shape), but other shapes such as semicircular, semielliptical, rectangular, etc. The area of the convex part 35, the number, the circumferential arrangement pitch, and the like can be arbitrarily changed. That is, the splines 41 and 61 are formed, and the convex portions (convex teeth) 41a and 61a of the splines 41 and 61 do not need to be the convex portions 35 of the concave-convex fitting structure M. Alternatively, 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 suffices that the entire fitting contact portion 38 between the portion 35 and the concave portion fitted thereto is in close contact, and that the rotational torque can be transmitted between the hub wheel 1 and the constant velocity universal joint T1.

  Further, the hole portion 22 of the hub wheel 1 may be a deformed hole such as a polygonal hole other than a circular hole, and the cross-sectional shape of the end portion of the shaft portion 12 to be inserted into the hole portion 22 may be other than a circular cross section. An irregular cross section such as a square may be used. Furthermore, since 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 when the shaft portion 12 is press-fitted into the hub wheel 1, it is necessary to increase the overall hardness of the convex portion 35. There is no. Although the gap 40 is formed in FIG. 3 and the like, the gap 40 between the convex portions 35 may bite into the inner diameter surface 37 of the hub wheel 1. The hardness difference between the convex portion 35 side and the concave portion forming surface formed by the convex portion 35 is preferably 20 points or more in HRC as described above, but the convex portion 35 can be press-fitted. If there is, it may be less than 20 points.

  Although the end surface (press-fit start end) of the convex portion 35 is a surface orthogonal to the axial direction in the embodiment, it may be inclined at a predetermined angle with respect to the axial direction. 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.

  Moreover, you may provide the small recessed part arrange | positioned by the predetermined pitch along the circumferential direction in the internal diameter surface 37 of the hole 22 of the hub wheel 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 pocket part 50 can be made small and the workability of the pocket part 50 and the improvement of the intensity | strength of the axial part 12 can be aimed at. In addition, the shape of a small recessed part can employ | adopt various things, such as a triangle shape, a semi-ellipse shape, and a rectangle, and can also set the number arbitrarily.

  A roller may be used as the rolling element 30 of the rolling bearing 2. When press-fitting, even if the hub wheel 1 side is fixed and the shaft portion 12 side is moved, conversely, the shaft portion 12 is fixed and the hub wheel 1 side is moved, either of which is moved. May be. In the constant velocity universal joint 3, the inner ring 6 and the drive shaft 10 may be integrated via the concave-convex fitting structure M described in each of the above embodiments.

  In the wheel bearing device shown in FIGS. 2, 7, and 8, the outer member 25 is of a type provided with a flange 25a. However, as shown in FIG. It is good also as a type in which the outer-diameter surface of the direction member 25 is press-fit.

  The sliding type constant velocity universal joint on the inboard side is not limited to the tripod type, and other sliding type constant velocity universal joints can be used.

It is a longitudinal cross-sectional view of the axle module which shows 1st Embodiment of this invention. It is an expanded sectional view of the wheel bearing device of the axle module. The uneven | corrugated fitting structure of the said wheel bearing apparatus is shown, (a) is an expanded sectional view, (b) is the X section enlarged view of (a). It is a principal part expanded sectional view of the wheel bearing apparatus. It is sectional drawing which shows before the assembly of the said bearing apparatus for wheels. The modification of an uneven | corrugated fitting structure is shown, (a) is sectional drawing of a 1st modification, (b) is sectional drawing of a 2nd modification. It is a longitudinal cross-sectional view of the wheel bearing apparatus of the axle module which shows 2nd Embodiment of this invention. It is a longitudinal cross-sectional view of the wheel bearing apparatus of the axle module which shows 3rd Embodiment of this invention. It is a longitudinal cross-sectional view of the wheel bearing apparatus of the axle module which shows 4th Embodiment of this invention. It is a longitudinal cross-sectional view of the axle module which shows 5th Embodiment of this invention. The 3rd modification of an uneven | corrugated fitting structure is shown, (a) is an expanded sectional view, (b) is the Y section enlarged view of (a). It is sectional drawing of the conventional wheel bearing apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hub wheel 2 Rolling bearing 3 Constant velocity universal joint 10 Drive shaft 26 Outer raceway surface 27 Outer raceway surface 28, 29 Inner race 30 Rolling element 35 Convex part 36 Concave part 65 Expanded diameter caulking part (tapered locking piece)
92 Wheel Pilot M Concavity and convexity fitting structure T1 Outboard side constant velocity universal joint T2 Inboard side constant velocity universal joint

Claims (10)

A constant velocity that includes a bearing having a plurality of rows of rolling elements arranged between the outer race and the inner race facing each other, a hub wheel attached to the wheel, and a constant velocity universal joint, and is fitted into a hole of the hub wheel. A bearing device for a wheel in which a shaft portion of an outer joint member of a universal joint is integrated with a hub wheel via an uneven fitting structure,
Of the shaft portion of the outer joint member and the hole portion of the hub wheel, the convex portion extending in the axial direction provided in one of the two is press-fitted into the other, and the concave portion that closely fits the convex portion on the other is formed by the convex portion. By forming, a concave-convex fitting structure in which the entire fitting contact portion between the convex portion and the concave portion is in close contact with each other, and at least the inner diameter surface of the hub wheel and the outer diameter surface of the end portion on the outboard side of the shaft portion, A wheel bearing device, characterized in that a coating film is formed to close the gaps of the wheel.   An end portion of the shaft portion of the outer joint member is formed with an enlarged caulking portion that engages with the inner diameter surface of the hub wheel, and the coating film is at least the inner diameter surface of the hub wheel and the outer diameter caulking portion of the outer joint member. The wheel bearing device according to claim 1, wherein a gap between the outer diameter surfaces of the wheels is closed.   The said coating film is provided in the range which reaches the shaft end surface of the axial part of an outer joint member, and the hub ring inner-diameter surface of an outboard side rather than this shaft end surface. The wheel bearing apparatus described in 1.   A short cylindrical wheel pilot is provided on the outboard side of the hub wheel, and the coating film has a shaft end surface of the shaft portion of the outer joint member, the entire inner diameter surface of the hub wheel on the outboard side from the shaft end surface, and the wheel pilot. 3. The wheel bearing device according to claim 1, wherein the wheel bearing device is provided in a range extending to an outer diameter surface of the wheel.   The wheel bearing device according to any one of claims 1 to 4, wherein the coating film is formed by an electrodeposition coating method.   The wheel bearing device according to claim 5, wherein the electrodeposition coating method is a cationic electrodeposition coating method.   The wheel bearing device according to claim 6, wherein a zinc phosphate coating is formed as a base treatment of the coating coating.   The wheel bearing device according to claim 6, wherein a galvanized film is formed as a base treatment of the paint film.   The wheel bearing device according to any one of claims 5 to 8, wherein the coating film thickness is set in a range of 10 to 50 µm.   A drive shaft comprising the wheel bearing device according to any one of claims 1 to 9, connected to a constant velocity universal joint on an outboard side, and an inboard connected to the other of the drive shafts Axle module comprising a side sliding type constant velocity universal joint.

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