JP2009292422A - Bearing device for drive wheel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing device for a drive wheel, improved in durability, while improved in workability of disassembling and reassembling. <P>SOLUTION: The bearing device for a derive wheel has an inner ring 5 fixed to a hub ring 1 by a caulking part 13 formed by plastically deforming an end part of a small diameter step part 1b, outward in a diameter direction. An outside joint member 14 of a constant velocity universal joint 3 integrally has a shoulder part 19, and a cylinder-like shaft 20 extending from the shoulder part 19 in a shaft direction and having a female screw 20a formed therein. Face splines 19a and 13a are formed in the end surfaces of the shoulder part 19 and the caulking part 13, respectively, and are pressure supported by a fastening bolt 21 abutted on the end surface of outer side of the hub ring 1 and screwed in the female screw 20a of the shaft 20. Compressive residual stress is given the surfaces of both face splines 19a and 13a through surface reforming by shot peening, and the surface hardness is set at 300Hv or more. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a drive wheel bearing device that rotatably supports a drive wheel of a vehicle such as an automobile, and more particularly to a drive wheel bearing device in which a bearing portion and a constant velocity universal joint are detachably unitized.

  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 a rough road. In addition, one end of the drive shaft that is interposed between the engine side and the drive wheel side is connected to the differential through a sliding type constant velocity universal joint, and the other end is It is connected to the wheel via a drive wheel bearing device including a fixed type constant velocity universal joint.

  In recent years, demands for improving fuel efficiency have been severe from the viewpoint of resource saving or pollution. In automobile parts, weight reduction of a wheel bearing device has been noticed as a factor to meet such a demand and has been strongly desired for a long time. There are various proposals related to wheel bearing devices that have been reduced in weight, but it is also important to simplify the assembly and disassembly work and reduce the cost at the assembly site of automobiles and the repair market. It is a factor.

  The drive wheel bearing device shown in FIG. 9 is a typical example that satisfies these requirements. This drive wheel bearing device is configured by detachably uniting a double row rolling bearing 51 and a constant velocity universal joint 52. The double row rolling bearing 51 is integrally provided with a vehicle body mounting flange 53b for mounting to the vehicle body, an outer member 53 having double row outer rolling surfaces 53a and 53a formed on the inner periphery, and a wheel at one end. A wheel mounting flange 54b for mounting (not shown) is integrally formed, an inner rolling surface 54a facing one of the double row outer rolling surfaces 53a, 53a on the outer periphery, and the inner rolling surface 54a. A hub wheel 54 having a cylindrical small-diameter step 54c extending in the axial direction from the outer periphery, and a small-diameter step 54c of the hub wheel 54 are press-fitted to the other outer side of the double row outer rolling surfaces 53a and 53a. An inner member 56 composed of an inner ring 55 formed with opposing inner rolling surfaces 55a, and double row rolling elements 58, 58 accommodated between the both rolling surfaces via a retainer 57 so as to be freely rollable. I have. The inner ring 55 is fixed in the axial direction with respect to the hub ring 54 by a caulking portion 59 formed by plastically deforming an end portion of the small diameter step portion 54c. Further, a face spline 59 a is formed on the end surface of the crimping portion 59. Here, the face spline 59a of the caulking portion 59 is formed simultaneously with the caulking process.

  Further, seals 60 and 61 are attached to the opening portion of the annular space formed between the outer member 53 and the inner member 56, and leakage of grease sealed inside the bearing to the outside and rainwater from the outside. And dust are prevented from entering the bearing.

  The constant velocity universal joint 52 includes an outer joint member 62, a joint inner ring 63, a cage 64, and a torque transmission ball 65. The outer joint member 62 forms a cup-shaped mouth portion 66 and a bottom portion of the mouth portion 66. A shoulder portion 67 and a hollow shaft portion 68 extending in the axial direction from the shoulder portion 67 are integrally provided, and a female screw 68 a is formed on the inner periphery of the shaft portion 68. A face spline 67 a is formed on the end surface of the shoulder portion 67. The face spline 67a is engaged with the face spline 59a formed on the end surface of the crimping portion 59, and the rotational torque from the drive shaft (not shown) is transferred to the wheel via the constant velocity universal joint 52 and the inner member 56. It is transmitted to the mounting flange 54b.

Here, the fastening bolt 69 is screwed onto the female screw 68a of the shaft portion 68, and both the face splines 67a, 59a of the outer joint member 62 and the inner member 56 which are opposed to each other are pressed against and supported by the fastening bolt 69. A rolling bearing 51 and a constant velocity universal joint 52 are detachably unitized. As a result, it is possible to reduce the weight and size, and to simplify the disassembly / assembly work.
Japanese Unexamined Patent Publication No. 63-184501

  In such a drive wheel bearing device, since the face spline 59a is formed at the time of swing caulking together with the caulking portion 59, workability is improved, and the number of processing steps can be reduced and the cost can be reduced. Further, since the torque is transmitted by the face splines 59a and 67a, it is possible to achieve light weight and compactness and to simplify the disassembly / assembly work. However, since the face spline 59a is formed at the time of swinging caulking at the same time as the caulking portion 59, the surface of the tooth surface remains the surface hardness after cold plastic working, and the surface of the hub wheel 54 after forging. It is only a little higher than the hardness. In general, since the fatigue strength increases in proportion to the surface hardness, an increase in the fatigue strength of the face spline 59a cannot be expected so much.

  Here, it is conceivable that both face splines 59a and 67a are induction-quenched to increase the surface hardness, improve the wear resistance, and increase the fatigue strength, but in this case, the face splines 59a, Not only is the meshing of 67a broken, but also a decrease in toughness due to high hardness is undesirable.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a drive wheel bearing device that improves workability at the time of disassembly and assembly and also improves durability.

  In order to achieve such an object, the invention according to claim 1 of the present invention is a drive wheel bearing device in which a double row rolling bearing and a constant velocity universal joint are detachably unitized, The rolling bearing has a body mounting flange integrally attached to the vehicle body on the outer periphery, an outer member integrally formed with a double row outer rolling surface on the inner periphery, and a wheel for mounting a wheel on one end. A wheel mounting flange is integrally formed, and one inner rolling surface facing the outer rolling surface of the double row is formed on the outer periphery, and a cylindrical small-diameter step portion extending in the axial direction from the inner rolling surface is formed. A hub ring, an inner member that is externally fitted to the hub ring, and has an inner ring formed on the outer circumference with the other inner rolling surface facing the double-row outer rolling surface, and the inner member and the outer member. A double-row rolling element housed in a freely rolling manner between both rolling surfaces of the side member, The inner ring is fixed to the hub ring by a caulking portion formed by plastically deforming the end portion of the radial step portion radially outward, and the constant velocity universal joint includes a cup-shaped mouth portion and the mouse. An outer joint member integrally including a shoulder portion forming a bottom portion of the portion and a cylindrical shaft portion extending in an axial direction from the shoulder portion and formed with a female screw, and the shoulder portion of the outer joint member and the caulking portion Face splines are respectively formed on the end faces of the parts, and both face splines are pressed against and supported by fastening bolts that are in contact with the outer end face of the hub wheel and screwed to the female thread of the shaft part, and the double row rolling In a drive wheel bearing device in which a bearing and a constant velocity universal joint are coupled so that torque can be transmitted and can be separated in an axial direction, compressive residual stress is applied to the surfaces of both face splines by surface modification.

  In this way, the inner ring is fixed to the hub ring by the caulking portion formed by plastically deforming the end portion of the small diameter step portion of the hub wheel radially outward, and the shoulder portion and the caulking portion of the outer joint member are fixed. Face splines are formed on each end face, and both face splines are pressed against and supported by fastening bolts that are in contact with the outer end face of the hub wheel and screwed into the internal thread of the shaft. In the drive wheel bearing device that is coupled so that torque can be transmitted and is separable in the axial direction, the compressive residual stress is applied to the surfaces of both face splines by surface modification, so there is no deformation due to heat treatment, The fatigue strength can be increased while maintaining the desired shape and dimensions, and the wear resistance can be improved to provide a high-quality and highly reliable drive wheel bearing device.

  Preferably, if the face spline of the caulking portion is formed by plastic working simultaneously with the caulking portion as in the invention described in claim 2, the number of processing steps can be reduced and the cost can be reduced. Can do.

  The invention according to claim 3 of the present invention is a drive wheel bearing device in which a double-row rolling bearing and a constant velocity universal joint are detachably unitized, and the double-row rolling bearing has an outer periphery. It has a body mounting flange that can be attached to the vehicle body, and an outer member that has a double row outer rolling surface formed integrally on the inner periphery, and a wheel mounting flange that is used to mount the wheel at one end. A hub ring formed on the outer periphery with one inner rolling surface facing the outer rolling surface of the double row, and a cylindrical small-diameter stepped portion extending in the axial direction from the inner rolling surface, and An inner member formed of a cylindrical inner ring member that is fitted in the hub ring and has an inner rolling surface opposite to the outer rolling surface of the double row formed on the outer periphery, and the inner member and the outer A double row rolling element accommodated between the rolling surfaces of the member so as to be freely rollable, The constant velocity universal joint has a cup-shaped mouth portion, a shoulder portion that forms the bottom portion of the mouth portion, and a cylindrical shaft portion that extends in the axial direction from the shoulder portion and has a female screw formed therein. A face spline is formed on the shoulder part of the outer joint member and the end face of the inner ring member, and is in contact with the end face on the outer side of the hub ring and screwed to the female screw of the shaft part. In the bearing device for a drive wheel, wherein the both face splines are pressed and supported by fastening bolts, and the double row rolling bearing and the constant velocity universal joint are coupled to be able to transmit torque and to be separated in the axial direction. The inner ring member and the inner ring member are integrally plastically bonded, and compressive residual stress is applied to the surfaces of the both face splines by surface modification.

  In this way, face splines are formed on the shoulder portion of the outer joint member and the end face of the inner ring member, respectively, and both faces are brought into contact by the fastening bolts that are in contact with the outer end face of the hub ring and screwed to the female screw of the shaft portion. In a bearing device for a drive wheel in which a spline is supported by pressure contact and a double-row rolling bearing and a constant velocity universal joint are coupled so that torque can be transmitted and separated in the axial direction, the hub wheel and inner ring member are integrally plastically coupled. At the same time, the compressive residual stress is applied to the surfaces of both face splines by surface modification, improving fatigue strength and wear resistance while maintaining the desired shape and dimensions, and face spline tooth misalignment and repetition. Variations due to processing can be avoided, and reliability can be improved.

  Preferably, if the face splines of the inner ring member are simultaneously formed by cold forging of the inner ring member as in the invention described in claim 4, the yield of the material can be improved.

  Further, as in the fifth aspect of the present invention, if a step is formed at the end of the inner ring member and the face spline is formed at the protruding end surface, the stylus of the measuring instrument is brought into contact with the step. Thus, the dimensions of a predetermined part can be measured, and the preload amount of the bearing can be easily managed.

  Further, as in the invention according to claim 6, a hardened uneven portion is formed on the inner periphery of the hub wheel, and the cylindrical portion of the inner ring member is fitted into the uneven portion, and the cylindrical portion is expanded. If the hub ring and the inner ring member are integrally plastically joined with a predetermined bearing preload applied, the preload is firmly tightened with a nut or the like as before. Since it is not necessary to manage the amount, it is possible to reduce the weight and size, improve the strength and durability of the hub wheel, and maintain the preload amount for a long time.

  Further, as in the invention according to claim 7, the cylindrical portion of the inner ring member is fitted into the hub wheel, and the end portion of the cylindrical portion is formed by plastic deformation radially outward. The hub ring and the inner ring member may be integrally plastically coupled with each other in a state where a predetermined bearing preload is applied.

  Further, as in the invention according to claim 8, the fastening bolt is screwed onto the female screw of the shaft portion via a spacer, and the spacer is formed in a substantially L-shaped cross section. If it has the flange part which contact | abuts the end surface of this, and the cylindrical part guided by the said fastening bolt, the outer joint member and the inner member can be easily centered by the spacer, and the device can be disassembled. -Assembling work is simplified, and both face splines can be engaged with each other without play in the circumferential direction and the axial direction.

  Further, as in the ninth aspect of the invention, a guide portion is formed on the inner periphery of the cylindrical portion of the inner ring member so as to protrude radially inward, and the fastening bolt is inserted into the guide portion so that the fastening bolt is connected to the shaft. If it is screwed to the female thread of the part, the centering of the outer joint member and the inner member can be facilitated, and the disassembly / assembly work of the apparatus is simplified.

  Further, as in the invention described in claim 10, if the surface hardness of the face spline is set to 300 Hv or more, the mechanical strength and fatigue strength of the material can be maximized and Abrasion can be improved.

  Further, as in the invention described in claim 11, the surface of the face spline may be subjected to shot peening or WPC treatment as surface modification.

  In addition, if the surface of the face spline is hardened by laser hardening as in the invention described in claim 12, the heat treatment deformation is suppressed, and the tooth surface surface strength and wear resistance of the face spline are improved. Thus, reliability can be improved over a long period of time.

  A drive wheel bearing device according to the present invention is a drive wheel bearing device in which a double-row rolling bearing and a constant velocity universal joint are detachably unitized, and the double-row rolling bearing is attached to the vehicle body on the outer periphery. A body mounting flange for mounting is integrally formed, an outer member in which a double row outer raceway surface is integrally formed on the inner periphery, and a wheel mounting flange for mounting a wheel on one end are integrated. A hub wheel formed on the outer periphery with one inner rolling surface facing the outer rolling surface of the double row, a cylindrical small diameter step portion extending in an axial direction from the inner rolling surface, and the hub wheel An inner member comprising an inner ring that is externally fitted and has the other inner rolling surface facing the outer rolling surface of the double row on the outer periphery, and between both rolling surfaces of the inner member and the outer member A plurality of rolling elements accommodated in a freely rotatable manner, and the end of the small diameter step portion is radially The inner ring is fixed to the hub ring by a caulking portion formed by plastic deformation in the direction, and the constant velocity universal joint includes a cup-shaped mouth portion, a shoulder portion that forms the bottom portion of the mouth portion, An outer joint member that extends in the axial direction from the shoulder portion and integrally has a cylindrical shaft portion formed with a female thread is formed.Face splines are formed on the shoulder portion of the outer joint member and the end surface of the caulking portion, respectively. The both face splines are pressed against and supported by fastening bolts that are brought into contact with the outer end face of the hub wheel and screwed into the female screw of the shaft portion, and the double row rolling bearing and the constant velocity universal joint transmit torque. In the drive wheel bearing device coupled in a separable manner and in the axial direction, since the compressive residual stress is applied to the surfaces of the both face splines by surface modification, there is no deformation due to heat treatment, It is possible to increase the left fatigue strength of Nozomu shape and size, it is possible to provide a highly reliable drive wheel bearing device with high quality by improving the wear resistance.

  A drive wheel bearing device in which a double-row rolling bearing and a constant velocity universal joint are detachably unitized, and the double-row rolling bearing has an integrally mounted vehicle body mounting flange on the outer periphery. And an outer member integrally formed with a double row outer rolling surface on the inner periphery, and a wheel mounting flange for attaching a wheel to one end, and the outer rolling surface of the double row on the outer periphery. And a hub wheel formed with a cylindrical small-diameter stepped portion extending in an axial direction from the inner rolling surface, and an outer fit of the hub wheel, and an outer periphery of the double row on the outer periphery. An inner member formed of an inner ring formed with the other inner rolling surface facing the rolling surface, and a double row of the inner member and the outer member accommodated in a freely rolling manner between the rolling surfaces of the inner member and the outer member. A caulking portion that includes a rolling element and is formed by plastically deforming an end portion of the small diameter step portion radially outward. The inner ring is fixed to the hub wheel, and the constant velocity universal joint includes a cup-shaped mouth portion, a shoulder portion that forms the bottom portion of the mouth portion, and an axial direction extending from the shoulder portion to form a female screw. And an outer joint member integrally formed with the cylindrical shaft portion. Face splines are respectively formed on the shoulder portion of the outer joint member and the end surface of the caulking portion, and contact the outer end surface of the hub wheel. Both face splines are pressed against and supported by fastening bolts that are in contact with and screwed into the internal threads of the shaft portion, and the double row rolling bearings and constant velocity universal joints are coupled so as to be able to transmit torque and be separated in the axial direction. In the drive wheel bearing device, the face spline of the caulking portion is formed by plastic working at the same time as the caulking portion, and shot pein is formed on the surfaces of the both face splines. Compressive residual stress in the surface modification is applied, the surface hardness is set above 300Hv by.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
1 is a longitudinal sectional view showing a first embodiment of a bearing device for a drive wheel according to the present invention, FIG. 2 is a longitudinal sectional view showing a bearing portion of FIG. 1, and FIG. 3 is a constant velocity universal joint portion. It is a longitudinal cross-sectional view shown. In the following description, the side closer to the outer side of the vehicle when assembled to the vehicle is referred to as the outer side (left side in FIG. 1), and the side closer to the center is referred to as the inner side (right side in FIG. 1).

  This drive wheel bearing device has a so-called third generation configuration in which the hub wheel 1, the double row rolling bearing 2 and the constant velocity universal joint 3 are detachably unitized. The double-row rolling bearing 2 includes an outer member 7, an inner member 8, and double-row rolling elements (balls) 9 and 9.

  The outer member 7 is made of medium-high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and integrally has a vehicle body mounting flange 7b for mounting to a vehicle body (not shown) on the outer periphery. The double row outer rolling surfaces 7a, 7a are integrally formed. Then, at least the double row outer raceway surfaces 7a and 7a are subjected to a curing process in a surface hardness of 58 to 64 HRC by induction hardening.

  On the other hand, the inner member 8 is formed with double-row inner rolling surfaces 1a and 5a facing the outer rolling surfaces 7a and 7a of the outer member 7 described above. Of these double-row inner rolling surfaces 1a, 5a, one (outer side) inner rolling surface 1a is on the outer periphery of the hub wheel 1, and the other (inner side) inner rolling surface 5a is on the outer periphery of the inner ring 5, respectively. It is integrally formed. In this case, the inner member 8 refers to the hub wheel 1 and the inner ring 5. And the double row rolling elements 9 and 9 are accommodated between these both rolling surfaces, respectively, and are hold | maintained by the holder | retainers 10 and 10 so that rolling is possible. Further, seals 11 and 12 are attached to the opening portion of the annular space formed between the outer member 7 and the inner member 8, and leakage of the lubricating grease sealed inside the bearing and the inside of the bearing from the outside. Prevents intrusion of rainwater and dust.

  As shown in an enlarged view in FIG. 2, the hub wheel 1 integrally has a wheel mounting flange 4 for mounting a wheel (not shown) at an end portion on the outer side, and a shaft from the inner rolling surface 1 a to the outer periphery. A cylindrical small-diameter step portion 1b extending in the direction is formed. This hub wheel 1 is made of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and includes an inner rolling surface 1a and an inner side of a wheel mounting flange 4 that serves as a seal land portion of an outer side seal 11. The outer peripheral surface extending from the base portion 4a on the side to the small-diameter step portion 1b is subjected to a hardening treatment in a range of 58 to 64 HRC by induction hardening. As a result, not only the wear resistance of the seal land portion is improved, but also the mechanical strength against the rotational bending load applied to the wheel mounting flange 4 is sufficient, and the durability of the hub wheel 1 is further improved. . The inner ring 5 and the rolling elements 9 are made of high carbon chrome steel such as SUJ2, and are hardened in the range of 58 to 64 HRC up to the core portion by quenching.

  The inner ring 5 is press-fitted into the small-diameter step portion 1b of the hub wheel 1 through a predetermined scissors, and a desired bearing preload is applied by a crimping portion 13 formed by plastic deformation of the end portion of the small-diameter step portion 1b. It is fixed in the axial direction. A face spline 13a is formed on the end face of the crimping portion 13 by plastic working during swing caulking. In addition, although the double row angular contact ball bearing which used the ball for the rolling element 9 was illustrated here, not only this but the double row tapered roller bearing which used the tapered roller for the rolling element 9 may be sufficient.

  The constant velocity universal joint 3 includes an outer joint member 14, a joint inner ring 15, a cage 16 and a torque transmission ball 17 as shown in an enlarged manner in FIG. 3. The outer joint member 14 has a cup-shaped mouth portion 18, a shoulder portion 19 that forms the bottom of the mouth portion 18, and a cylindrical shaft portion 20 that extends in an axial direction from the shoulder portion 19. Curved track grooves 18a and 15a extending in the axial direction are formed on the inner periphery of the inner ring 15 and the outer periphery of the joint inner ring 15, respectively. A face spline 19 a that engages with the face spline 13 a of the caulking portion 13 is formed on the end surface of the shoulder portion 19, and a female screw 20 a is formed on the shaft portion 20. The outer joint member 14 is made of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and the track groove 18a is hardened by induction hardening in a range of 58 to 64 HRC.

  Further, as shown in FIG. 1, a fastening bolt 21 is screwed onto the female screw 20 a of the shaft portion 20, and the shoulder portion 19 of the outer joint member 14 and the crimping portion 13 of the hub wheel 1 are opposed by the fastening bolt 21. Both face splines 19a and 13a are supported by pressure contact, and the double row rolling bearing 2 and the constant velocity universal joint 3 are detachably unitized. In the present embodiment, since the small-diameter portion 1c into which the fastening bolt 21 is inserted through a predetermined guide clearance is formed on the inner diameter of the hub wheel 1, the outer joint member 14 and the inner member 8 can be easily centered. The disassembling / assembling work of the apparatus is simplified, and both face splines 19a, 13a can be engaged with each other without play in the circumferential direction and the axial direction.

  Here, the face spline 13a of the caulking portion 13 and the face spline 19a of the shoulder portion 19 of the outer joint member 14 are given compressive residual stress by surface modification by shot peening. As a result, the fatigue strength can be increased while maintaining the desired shape and dimensions without deformation due to heat treatment. As the shot grain, a steel ball having a particle size in the range of several tens of μm to 0.1 mm is used, but other non-ferrous shots such as ceramics may be used. The shot peening treatment conditions are a pressure of 0.4 MPa, a treatment time of 20 seconds, and an injection distance of 100 mm.

  In the test performed by the applicant of the present invention on a test piece consisting of S53C to S55C, although there are some differences depending on shot grains and projection conditions, if the surface hardness of the surface to be formed is set to at least about 300 HV, the surface has 500 MPa. It has been found that a compressive residual stress can be formed, and if it is set to 520 HV or higher, a compressive residual stress of about 1000 MPa can be formed on the extreme surface layer. As a result, even if the face spline 13a is simultaneously formed by plastic working of the caulking portion 13 and a tensile residual stress is generated on the surface thereof, a sufficient compressive residual stress is formed on the surface, and the mechanical strength of the material And the fatigue strength can be maximized.

  In addition to this shot peening, as means for imparting compressive residual stress, WPC (Wide Peening Cleaning) processing that makes the particle size of shot grains finer than shot peening and collides with the surface to be formed at higher speed is exemplified. Can do. By this WPC treatment, it is possible to further improve fatigue strength and wear resistance, and to provide a high-quality and highly reliable drive wheel bearing device.

  Further, the surface of both face splines 13a and 19a may be subjected to a hardening process by laser hardening. Thereby, while suppressing heat processing deformation | transformation, the improvement of the intensity | strength of a tooth surface and wear resistance of both face splines 13a and 19a can be aimed at, and reliability can be improved over a long period of time.

  As described above, both the face splines 13a and 19a may be subjected to shot peening, WPC treatment, or hardening by laser quenching. However, the present invention is not limited to this. For example, the face spline 13a of the caulking portion 13 may be used. Each of the combinations may be appropriately performed, for example, by performing a hardening process by laser hardening on the surface and performing shot peening on the face spline 19 a of the shoulder 19.

  FIG. 4 is a longitudinal sectional view showing a second embodiment of the bearing device for a driving wheel according to the present invention, and FIG. 5 is a longitudinal sectional view showing the bearing portion of FIG. Note that this embodiment basically differs from the first embodiment described above only in the configuration of the double row rolling bearings, and the same reference numerals are assigned to the same parts or parts having the same functions. Therefore, detailed description is omitted.

  The drive wheel bearing device has a so-called third generation configuration in which the hub wheel 22, the double row rolling bearing 23, and the constant velocity universal joint 3 are detachably unitized. The double row rolling bearing 23 includes an outer member 7, an inner member 24, and double row rolling elements 9 and 9.

  As shown in FIG. 5 in an enlarged manner, the inner member 24 is formed with double rows of inner rolling surfaces 1a, 5a facing the outer rolling surfaces 7a, 7a of the outer member 7. Of these double-row inner rolling surfaces 1a and 5a, one (outer side) inner rolling surface 1a is on the outer periphery of the hub wheel 22, and the other (inner side) inner rolling surface 5a is on the outer periphery of the inner ring member 25. Each is integrally formed. In this case, the inner member 24 refers to the hub wheel 22 and the inner ring member 25.

  The hub wheel 22 integrally has a wheel mounting flange 4 at an end on the outer side, a cylindrical small diameter step portion 22a extending in the axial direction from the inner rolling surface 1a is formed on the outer periphery, and induction hardening is performed on the inner periphery. Thus, the concavo-convex portion 26 having a surface hardness of 54 to 64 HRC is formed (indicated by cross-hatching in the figure). The concave and convex portion 26 is formed in the shape of an iris knurl, and is a cross groove formed by orthogonally crossing a plurality of annular grooves formed independently by turning or the like and a plurality of axial grooves formed by broaching or the like. Alternatively, it consists of a cross groove composed of spiral grooves inclined with respect to each other. Moreover, in order to ensure good biting property, the tip of the concavo-convex portion 26 is formed in a spire shape such as a triangular shape.

  The hub wheel 22 is made of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and the outer circumference extends from the inner rolling surface 1a to the small diameter step portion 22a from the base portion 4a on the inner side of the wheel mounting flange 4. The surface is hardened by induction hardening to a surface hardness of 58 to 64 HRC (indicated by cross-hatching in the figure). Thereby, not only the wear resistance of the base portion 4a of the wheel mounting flange 4, that is, the seal land portion, is improved, but also has sufficient mechanical strength against the rotational bending load applied to the wheel mounting flange 4. The durability of the hub wheel 22 is further improved.

  The inner ring member 25 is integrally formed with a cylindrical portion 27 extending in the axial direction from the inner rolling surface 5a. The cylindrical portion 27 is formed at an end portion of the in-row portion 27a, which is fitted into the small-diameter step portion 22a of the hub wheel 22 via a predetermined shimiro, and is opposed to the uneven portion 26 of the hub wheel 22. And a fitting portion 27b. Further, a face spline 25 a is formed on the inner end face of the inner ring member 25. The inner ring member 25 is made of medium-high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and the surface hardness is set to a range of 58 to 64 HRC by induction quenching from the inner rolling surface 5a to the in-row portion 27a. Curing treatment is performed (indicated by cross-hatching in the figure). In addition, the fitting part 27b is made into the raw material hardness after forging.

  Here, the cylindrical portion 27 of the inner ring member 25 is fitted into the hub wheel 22, and a diameter expanding jig such as a mandrel is pushed into the fitting portion 27 b to expand the diameter of the fitting portion 27 b. The hub wheel 22 and the inner ring member 25 are plastically joined together in a state where a desired bearing preload is applied by so-called diameter expansion caulking, which is bitten into the concave-convex portion 26 of the hub wheel 22 and caulked. As a result, it is not necessary to control the preload by tightening firmly with a nut or the like as in the prior art, so that the weight and size can be reduced, the strength and durability of the hub wheel 22 can be improved, and the length can be increased. The amount of preload can be maintained for a period.

  Moreover, in this embodiment, the inner ring member 25 is formed by cold forging including the face spline 25a. Thereafter, turning is performed to a predetermined shape and size, and a predetermined portion is heat-treated, and then compressive residual stress is applied to the face spline 25a by surface modification by shot peening. Thereafter, at least the inner rolling surface 5a is ground. Thereby, as in the first embodiment described above, there is a problem caused by forming the face spline 13a at the same time as the caulking portion 13 in the state of the finished product, that is, tooth misalignment of the face spline 13a and variation due to repeated processing, Or the fall of durability by the hoop stress which generate | occur | produces in the inner ring | wheel 5 can be avoided, reliability can be improved further, and the cost increase by discard of the finished product by this malfunction can be prevented.

  Here, the fastening bolt 21 is screwed onto the female screw 20 a of the shaft portion 20, and both the face splines 19 a and 25 a facing the outer joint member 14 and the inner member 24 are pressed by the fastening bolt 21 via the spacer 29. The double row rolling bearing 23 and the constant velocity universal joint 3 are supported and detachably unitized. The spacer 29 has a substantially L-shaped cross section, and has a flange portion 29 a that abuts on the outer end surface of the hub wheel 22, and a cylindrical portion 29 b that is externally attached to the fastening bolt 21. Thereby, the centering of the outer joint member 14 and the inner member 24 can be facilitated by the spacer 29, the disassembling / assembling work of the apparatus is simplified, and both the face splines 19a, 25a are free from play in the circumferential direction and the axial direction. Can be engaged.

  In this manner, the face spline 25a is free of play due to the spacer 29 and is subjected to surface modification by shot peening, so that it is less likely to be worn by repeated contact. Further, here, the face spline 25a is formed by cold forging in order to improve the yield, but not limited to this, the inner ring member 25 is formed by hot forging and then formed by turning. Alternatively, it may be formed by plastic working such as swing rolling after turning.

  FIG. 6 is a longitudinal sectional view showing a third embodiment of the bearing device for a drive wheel according to the present invention, and FIG. 7 is a longitudinal sectional view showing the bearing portion of FIG. In addition, the same code | symbol is attached | subjected to the components and site | parts similar to embodiment mentioned above, or the components and site | parts which have the same function, and detailed description is abbreviate | omitted.

  As shown in FIG. 6, the drive wheel bearing device has a configuration called a third generation in which the hub wheel 30, the double row rolling bearing 31, and the constant velocity universal joint 3 are detachably unitized. . As shown in an enlarged view in FIG. 7, the double row rolling bearing 31 includes an outer member 7, an inner member 32, and double row rolling elements 9 and 9. The inner member 32 includes a hub wheel 30 and an inner ring member 33 fitted in the hub wheel 30, and the double-row inner rolling surface 1 a facing the outer rolling surfaces 7 a and 7 a of the outer member 7. 5a is formed.

  The hub wheel 30 integrally has a wheel mounting flange 4 at an end portion on the outer side, and a cylindrical small-diameter step portion 22a extending in the axial direction from the inner rolling surface 1a is formed on the outer periphery. The hub wheel 30 is made of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and extends from the inner rolling surface 1a to the small diameter step portion 22a from the base portion 4a on the inner side of the wheel mounting flange 4. The outer peripheral surface and the inner peripheral surface are hardened by induction hardening to a surface hardness of 58 to 64 HRC (only the hardened portion of the inner peripheral surface is shown by cross-hatching in the figure).

  The inner ring member 33 is integrally formed with a cylindrical portion 34 extending in the axial direction from the inner rolling surface 5a. The inner ring member 33 and the hub ring 30 are plastically coupled together in a state where a predetermined bearing preload is applied by a caulking portion 34a formed by plastically deforming the end portion of the cylindrical portion 34 radially outward. ing. The inner ring member 33 is made of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and the surface hardness of the outer diameter surface extending from the inner rolling surface 5a to the cylindrical portion 34 is 58 to 64 HRC by induction hardening. The range is hardened (indicated by cross-hatching in the figure). In addition, the edge part of the cylindrical part 34 plastically processed is made the raw material hardness after forging, and the crimping part 34a is set to the range of 15-35 HRC including plastic hardening. Thereby, plastic working can be easily performed, generation of micro cracks associated with the plastic working can be suppressed, and the strength of the caulking portion 34a can be secured to maintain a strong bond over a long period of time.

  In this embodiment, after the inner ring member 33 is formed by cold forging including the face spline 25a, it is turned to a predetermined shape and size, and a predetermined part is heat treated, and then the face spline 25a is shot. Peening is performed and at least the inner rolling surface 5a is ground.

  Here, as shown in FIG. 6, the fastening bolt 21 is screwed onto the female screw 20 a of the shaft portion 20, and both the outer joint member 14 and the inner member 32 are opposed to each other by the fastening bolt 21 via the spacer 35. The face splines 19a and 25a are pressure-supported, and the double-row rolling bearing 31 and the constant velocity universal joint 3 are detachably unitized. The spacer 35 has a substantially L-shaped cross section, and has a flange portion 35 a that abuts on the end surface of the crimping portion 34 a and a cylindrical portion 35 b that is externally inserted into the fastening bolt 21. This facilitates centering of the outer joint member 14 and the inner member 32 by the spacer 35, simplifies the disassembling / assembling work of the apparatus, and is similar to a double row rolling bearing as in the fourth generation structure. The quick universal joint can be replaced independently without replacing the unit, which contributes to a reduction in total cost.

  FIG. 8 is a longitudinal sectional view showing a fourth embodiment of the drive wheel bearing device according to the present invention. This embodiment basically differs from the above-described third embodiment (FIG. 6) only in part of the configuration of the inner ring member. In addition, the same components and parts as those of the third embodiment or the same Parts / parts having functions are denoted by the same reference numerals, and detailed description thereof is omitted.

  This drive wheel bearing device has a structure called a third generation in which the hub wheel 30, the double row rolling bearing 36, and the constant velocity universal joint 3 are detachably unitized. The double-row rolling bearing 36 includes an outer member 7, an inner member 37, and double-row rolling elements 9 and 9. The inner member 37 includes a hub wheel 30 and an inner ring member 38 fitted in the hub wheel 30, and has a double row of inner rolling members facing the outer rolling surfaces 7 a and 7 a of the outer member 7 on the outer periphery. Surfaces 1a and 5a are formed.

  The inner ring member 38 is integrally formed with a cylindrical portion 39 extending in the axial direction from the inner rolling surface 5a. The inner ring member 38 and the hub ring 30 are integrally plastically coupled with a predetermined bearing preload applied by a caulking portion 34a formed by plastically deforming the end of the cylindrical portion 39 radially outward. ing. The inner ring member 38 is made of medium-high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and the outer surface extending from the inner rolling surface 5a to the cylindrical portion 39 is induction hardened to have a surface hardness of 58 to 64 HRC. The range is hardened (indicated by cross-hatching in the figure).

  Here, a guide portion 39a is formed on the inner periphery of the cylindrical portion 39 of the inner ring member 38 so as to protrude radially inward. Then, the fastening bolt 40 is inserted into the guide portion 39a and screwed into the female screw 20a of the shaft portion 20, and both the face splines 19a and 25a of the outer joint member 14 and the inner member 37 are pressed and supported by the fastening bolt 40. The double row rolling bearing 36 and the constant velocity universal joint 3 are detachably unitized. Thereby, unlike the embodiment described above, the centering of the outer joint member 14 and the inner member 37 can be facilitated without mounting the spacers 29 and 35, and the disassembly / assembly operation of the apparatus is simplified.

  The embodiment of the present invention has been described above, but the present invention is not limited to such an embodiment, and is merely an example, and various modifications can be made without departing from the scope of the present invention. Of course, the scope of the present invention is indicated by the description of the scope of claims, and further, the equivalent meanings described in the scope of claims and all modifications within the scope of the scope of the present invention are included. Including.

  The drive wheel bearing device according to the present invention can be applied to a drive wheel bearing device in which a double row rolling bearing having a hub wheel and a constant velocity universal joint are detachably unitized.

It is a longitudinal section showing a 1st embodiment of a bearing device for drive wheels concerning the present invention. It is a longitudinal cross-sectional view which shows the bearing part of FIG. It is a longitudinal cross-sectional view which shows the constant velocity universal joint of FIG. It is a longitudinal cross-sectional view which shows 2nd Embodiment of the bearing apparatus for drive wheels which concerns on this invention. It is a longitudinal cross-sectional view which shows the bearing part of FIG. It is a longitudinal cross-sectional view which shows 3rd Embodiment of the bearing apparatus for drive wheels which concerns on this invention. It is a longitudinal cross-sectional view which shows the bearing part of FIG. It is a longitudinal cross-sectional view which shows 4th Embodiment of the bearing apparatus for drive wheels which concerns on this invention. It is a longitudinal cross-sectional view which shows the conventional bearing apparatus for drive wheels.

Explanation of symbols

1, 22, 30 ..... Hub wheels 1a, 5a ..... Inner rolling surface 1b, 22a ... Small diameter step 1c ... Small diameter part 2, 23, 31, 36 ... Double row rolling bearing 3 ...・ ・ ・ ・ ・ ・ ・ ・ ・ Constant velocity universal joint 4 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Wheel mounting flange 4a ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Wheel mounting flange Inner side base 5 ... inner ring 7 ... outer member 7a ... ········ Outside rolling surface 7b ····························································・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Rolling element 10 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ Retainer 11 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Seal 12 on the outer side ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Seal 13 and 34a on the inner side ・ ・ ・ ・···························································································· Outer joint member 15 .... Joint inner rings 15a, 18a ... Track groove 16 ... Cage 17 ... ... Torque transmission ball 18 ... Mouse 19 ... Shoulder 20 ... ... shaft 20a ... female screw 21, 40 ... fastening bolt 25, 33, 38 ......... inside Member 26... Uneven portion 27, 29b, 34, 35b, 39. Cylindrical portion 27a ..... In-row portion 27b. ··············· Fitting portion 28 ········· step 29, 35 · · · · · · · Seats 29a, 35a ... Flange 39a ... Guide 51 ... Row rolling bearing 52 ... Constant velocity universal joint 53 ... Outer member 53a ... ... outside rolling surface 53b ... body mounting flange 54 ... hub wheel 54a, 55a ... Inner rolling surface 54b ...・ ・ ・ ・ Wheel mounting flange 54c ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Small diameter step 55 ・ ・ ・ ・ ・ ・ Inner ring 56 ・ ・ ・... inner member 57 ... retainer 58 ... rolling element 59 ································································· Face Spline 60, 61 ·········· Seal 62 ... outer joint member 63 ... joint inner ring 64 ...・ ・ Cage 65 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Torque transmission ball 66 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Mouse part 67 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ Shoulder 68 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Shaft 68a ・............ female thread 69 ............... fastening bolts

Claims (12)

A drive wheel bearing device in which a double-row rolling bearing and a constant velocity universal joint are detachably unitized,
The double-row rolling bearing integrally has a vehicle body mounting flange to be attached to the vehicle body on the outer periphery, and an outer member in which the double-row outer rolling surface is integrally formed on the inner periphery;
A wheel mounting flange for mounting the wheel at one end is integrally formed, one outer side rolling surface facing the outer side rolling surface of the double row on the outer periphery, and a cylindrical shape extending in the axial direction from the inner side rolling surface A hub ring formed with a small-diameter step portion, and an inner member formed of an inner ring that is externally fitted to the hub ring and has the other inner rolling surface facing the outer rolling surface of the double row on the outer periphery. ,
A double row rolling element housed in a freely rolling manner between the rolling surfaces of the inner member and the outer member;
The inner ring is fixed to the hub ring by a caulking portion formed by plastically deforming an end portion of the small diameter step portion radially outward,
The constant velocity universal joint has an outer portion integrally including a cup-shaped mouth portion, a shoulder portion that forms the bottom portion of the mouth portion, and a cylindrical shaft portion that extends in the axial direction from the shoulder portion and is formed with a female screw. Fastening provided with a joint member, face splines formed on the shoulder part of the outer joint member and the end face of the crimped part, respectively, abutting the end face on the outer side of the hub wheel and screwed to the female screw of the shaft part In the drive wheel bearing device in which the both face splines are pressed and supported by bolts, and the double row rolling bearing and the constant velocity universal joint are coupled to be able to transmit torque and to be separated in the axial direction.
A bearing device for a drive wheel, wherein a compressive residual stress is applied to the surfaces of the both face splines by surface modification.   The drive wheel bearing device according to claim 1, wherein the face spline of the caulking portion is formed by plastic working simultaneously with the caulking portion. A drive wheel bearing device in which a double-row rolling bearing and a constant velocity universal joint are detachably unitized,
The double-row rolling bearing integrally has a vehicle body mounting flange to be attached to the vehicle body on the outer periphery, and an outer member in which the double-row outer rolling surface is integrally formed on the inner periphery;
A wheel mounting flange for mounting the wheel at one end is integrally formed, one outer side rolling surface facing the outer side rolling surface of the double row on the outer periphery, and a cylindrical shape extending in the axial direction from the inner side rolling surface And a cylindrical inner ring member that is fitted into the hub ring and that has the other inner rolling surface facing the outer rolling surface of the double row on the outer periphery. An inner member;
With the inner member and a double row rolling element accommodated between the rolling surfaces of the outer member so as to roll freely,
The constant velocity universal joint has an outer portion integrally including a cup-shaped mouth portion, a shoulder portion that forms the bottom portion of the mouth portion, and a cylindrical shaft portion that extends in the axial direction from the shoulder portion and is formed with a female screw. A joint member,
Face splines are formed on the shoulder of the outer joint member and the end surface of the inner ring member, respectively.
Both face splines are pressed against and supported by fastening bolts that are in contact with the outer end face of the hub wheel and screwed into the female thread of the shaft portion, so that torque can be transmitted between the double row rolling bearings and the constant velocity universal joint. And a bearing device for a drive wheel coupled in an axially separable manner,
A bearing device for a drive wheel, characterized in that the hub wheel and the inner ring member are integrally plastically bonded and a compressive residual stress is applied to the surfaces of the both face splines by surface modification.   The bearing device for a drive wheel according to claim 3, wherein the face spline of the inner ring member is formed simultaneously by cold forging of the inner ring member.   The drive wheel bearing device according to claim 3 or 4, wherein a stepped portion is formed at an end portion of the inner ring member, and the face spline is formed at an end surface protruding.   A hardened uneven portion is formed on the inner periphery of the hub ring, and the cylindrical portion of the inner ring member is fitted into the uneven portion, and the diameter of the cylindrical portion is expanded to bite into the uneven portion. The bearing device for a drive wheel according to any one of claims 3 to 5, wherein the inner ring member and the inner ring member are integrally plastically joined in a state where a predetermined bearing preload is applied.   A cylindrical portion of the inner ring member is fitted into the hub ring, and the hub ring and the inner ring member are provided with a predetermined bearing by a crimping portion formed by plastically deforming an end portion of the cylindrical portion radially outward. The bearing device for a drive wheel according to any one of claims 3 to 5, wherein the bearing device is integrally plastically joined in a state where a preload is applied.   The fastening bolt is screwed onto the female screw of the shaft portion via a spacer, the spacer is formed in a substantially L-shaped cross section, and is in contact with the end surface of the hub wheel, and the fastening bolt The drive wheel bearing device according to any one of claims 3 to 7, further comprising a cylindrical portion guided by being extrapolated.   A guide portion is formed on the inner periphery of the cylindrical portion of the inner ring member so as to protrude inward in the radial direction, and the fastening bolt is screwed onto the female screw of the shaft portion by being inserted into the guide portion. The bearing apparatus for driving wheels in any one of 5 and 7.   The bearing device for a drive wheel according to any one of claims 1 to 9, wherein a surface hardness of the face spline is set to 300 Hv or more.   The bearing device for a drive wheel according to claim 1, wherein the surface of the face spline is subjected to shot peening or WPC treatment as a surface modification.   The bearing device for a drive wheel according to claim 1, wherein the surface of the face spline is subjected to a hardening process by laser hardening.

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