JP2017013079A - Processing method of bearing device for wheel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a processing method of a bearing device for a wheel which prevents the generation of cracks by improving the mechanical rigidity of a tooth part, and is improved in durability and a life by preventing the wobbling of an engagement part by improving wear resistance.SOLUTION: A cylinder part is formed in advance before a small-diameter step part 1b is plastically processed, a nose part 26 in which a caulking tool 29 abuts on a caulking part 10 at an inclination angle β is protrusively formed after the formation of the caulking part 10, a punch 33 in which a tooth form 32 for plastically processing a face spline 19 over an external peripheral part from a peripheral edge of the nose part 26 is arranged, and an oscillation shaft into which the punch 33 is non-rotatably fit, and in which a center shaft A is imparted with an inclination angle α with respect to an axial core L of a hub ring 1 is arranged. The caulking tool 29 is made to intrude into the hub ring 1, the punch 33 is push-pressed to an end part of the caulking part 10 by a prescribed processing force, a spindle which coincides with the axial core L of the hub ring 1 is rotated, the caulking tool 29 is oscillated, thus forming the face spline 19.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a processing method for a wheel bearing device that rotatably supports a wheel of a vehicle such as an automobile, and more particularly to a processing method for a 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 via a sliding type constant velocity universal joint, and the other end is It is connected to the wheel via a 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 wheel bearing device shown in FIG. 6 is a typical example that satisfies these requirements. This wheel bearing device has a so-called third generation configuration in which a hub wheel 51, a double row rolling bearing 52, and a constant velocity universal joint (not shown) are detachably unitized. The double-row rolling bearing 52 includes an outer member 54, an inner member 55, and double-row balls 56, 56.

  The outer member 54 integrally has a vehicle body mounting flange 54b for mounting to the vehicle body (not shown) on the outer periphery, and double row outer rolling surfaces 54a, 54a are integrally formed on the inner periphery. On the other hand, the inner member 55 is formed with double row inner rolling surfaces 51a and 57a facing the double row outer rolling surfaces 54a and 54a of the outer member 54 described above. Of these double-row inner rolling surfaces 51 a and 57 a, one inner rolling surface 51 a is integrally formed on the outer periphery of the hub wheel 51, and the other inner rolling surface 57 a is integrally formed on the outer periphery of the inner ring 57. Double-row balls 56 and 56 are accommodated between these rolling surfaces, respectively, and are held by the cages 58 and 58 so as to freely roll. Further, seals 61 and 62 are attached to the opening portion of the annular space formed between the outer member 54 and the inner member 55, 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.

  The hub wheel 51 integrally has a wheel mounting flange 59 for mounting a wheel (not shown) at one end, an inner rolling surface 51a on the outer periphery, and a cylindrical shape extending in the axial direction from the inner rolling surface 51a. The small diameter step portion 51b is formed. An inner ring 57 is press-fitted into the small-diameter step portion 51b through a predetermined scissors. The inner ring 57 has a shaft bearing with respect to the hub wheel 51 in a state where a predetermined bearing preload is applied by a crimping portion 60 formed by plastically deforming an end portion of the small diameter step portion 51b of the hub wheel 51 radially outward. It is fixed in the direction.

  Here, the face spline 53 is formed on the end surface of the crimping portion 60, and the face spline that meshes with the face spline 53 of the crimping portion 60 is formed by plastic working on the end surface of the shoulder portion of the outer joint member (not shown). Yes. The opposing face splines are pressed against and supported by fixing bolts that are screwed into the female screw of the shoulder portion, and the hub wheel 51 and the outer joint member are coupled to be separable in the axial direction.

  The hub wheel 51 is placed vertically on a base 64 on which a plurality of knock pins 63 are erected, with the side surface 59b of the wheel mounting flange 59 in contact with the vehicle, and is press-fitted into the wheel mounting flange 59. A knock pin 63 is inserted into an insertion hole 65 of a hub bolt (not shown) to be supported and fixed. As a result, the hub wheel 51 can be supported and fixed on the base without newly providing a fixing means.

  Further, the caulking portion 60 of the small diameter step portion 51b formed by plastic working is formed in the cylindrical portion 66 in advance before plastic working. The crimping tool 67 has a nose portion 68 projecting from the central portion of one end face, and a punch 70 in which a tooth profile 69 for plastic working the face spline 53 is formed from the periphery of the nose portion 68 to the outer peripheral portion. And a central axis A is provided with a rocking shaft 71 having a predetermined inclination angle α with respect to the axis L of the hub wheel 51. The punch 70 is fitted to the swing shaft 71 so as not to rotate by means of a key or the like so that the phase does not shift with respect to the hub wheel 51 during caulking. Here, the inclination angle α is set in a range of 4 to 6 °.

  The nose portion 68 of the punch 70 is formed so as to abut the end portion of the cylindrical portion 66 with a predetermined inclination angle β with respect to the inner diameter 66 a of the cylindrical portion 66. Here, the inclination angle β is set in the range of 15 to 35 °.

  Then, the caulking tool 67 is caused to enter the cylindrical portion 66 of the hub wheel 51, the punch 70 is pressed against the end portion of the cylindrical portion 66 with a predetermined processing force, and the main shaft (see FIG. By rotating the crimping tool 67, the crimping portion 60 is formed by plastic working, and at the same time, the face spline 53 is formed on the end surface of the crimping portion 60.

  By adopting such a caulking tool 67 and forming the caulking part 60 and the face spline 53 on the end face of the caulking part 60 simultaneously by plastic working by the integrated punch 70, the structure of the mold In addition to reducing mold processing and its assembly and management man-hours, it is possible to reduce costs, and as in the conventional caulking process, the material bites between the molds, generating burrs and It is possible to avoid problems such as dropping pieces staying and lowering operability, and preventing burrs from occurring in the caulking portion 60 and the face spline 53 to improve product quality (see, for example, Patent Document 1). .)

JP 2009-274515 A

  In such a wheel bearing device, since the face spline 53 is formed by swing caulking simultaneously with the caulking portion 60, workability is improved, and the number of processing steps can be reduced to reduce the cost. However, in the hub wheel 51, for example, the face spline 53 is processed in a state after hot forging a carbon steel for machine structure such as S53C, that is, in a non-heat-treated state, that is, in a so-called raw state, and the tooth portion is not heat-treated Since it is used, when the excessive torque is applied, or when the meshing accuracy with the face spline on the constant velocity universal joint side is not sufficient, the backlash of the engaging part due to deformation or wear of the tooth part of the face spline 53 There was a problem that occurred.

  The present invention has been made in view of such circumstances, and the caulking and face spline forming process is performed by a caulking punch in which a tooth mold is formed and caulking and face spline are simultaneously formed. After rough forming of the crimped part with a crimping punch that does not form a tooth mold, face spline is formed with a crimping punch with a new tooth mold, and the work hardening of the face spline tooth part is greater. Attention is paid to form the face spline by a so-called two-step caulking process, thereby improving the mechanical strength of the tooth portion to prevent the occurrence of cracks and improving the wear resistance to reduce the backlash of the engaging portion. It aims at providing the processing method of the bearing apparatus for wheels which prevented and improved the reliability and lifetime.

  In order to achieve such an object, the invention according to claim 1 of the present invention includes an outer member in which a double row outer rolling surface is integrally formed on the inner periphery, and a wheel attachment for attaching a wheel to one end. A hub ring integrally formed with a flange and formed with a cylindrical small-diameter step portion extending in the axial direction on the outer periphery, and at least one inner ring press-fitted into the small-diameter step portion of the hub ring. An inner member in which a double row inner rolling surface facing the rolling surface is formed, and a double row rolling element housed in a freely rolling manner between the inner member and the rolling surface of the outer member; The inner ring is fixed in the axial direction by a caulking portion formed by plastically deforming a small-diameter step portion of the hub wheel radially outward, and a face spline for torque transmission on an end surface of the caulking portion In the method for processing a wheel bearing device in which the end portion of the small diameter step portion is formed in advance. The caulking tool is formed in the cylindrical portion before the processing, and a nose portion protruding from the central portion of the one end surface with a predetermined inclination angle with respect to the inner diameter of the cylindrical portion. A punch formed in a shape for plastic working the caulking portion from the periphery of the nose to the outer periphery, and the phase of the punch is shifted from the hub wheel during caulking. A pivot shaft that is non-rotatably fitted so that a central axis is given a predetermined inclination angle with respect to the axis of the hub wheel, and the caulking tool is inserted into the hub wheel, and the punch Is pressed against the end portion of the cylindrical portion with a predetermined processing force, and the main shaft that coincides with the axis of the hub wheel is rotated to generate a swinging motion in the caulking tool. The first step formed by the deformation and the caulking tool extends from the periphery of the nose to the outer periphery. A punch formed with a tooth profile for plastic processing of the face spline; and the swing shaft to which the punch is fitted, the caulking tool is inserted into the hub wheel, and the punch is inserted into the caulking portion. And a second step in which the face spline is formed by plastic deformation by causing the caulking tool to oscillate by rotating the main shaft while pressing against the end of the face.

  In this way, the inner ring is fixed in the axial direction by the caulking portion formed by plastically deforming the small-diameter step portion of the hub wheel radially outward, and a face spline for torque transmission is provided on the end surface of the caulking portion. In the formed wheel bearing device machining method, the end of the small-diameter stepped portion is formed in advance in the cylindrical portion before plastic working, and a crimping tool is provided at a central portion of one end surface with respect to the inner diameter of the cylindrical portion. A punch formed in a shape for plastic processing the crimping portion from the peripheral edge of the nose portion to the outer peripheral portion, with a nose portion projecting against the end portion of the cylindrical portion with an inclination angle of This punch is non-rotatably fitted so that its phase does not shift with respect to the hub wheel during caulking, and the center shaft has a swing shaft with a predetermined inclination angle with respect to the hub wheel axis. The caulking tool enters the hub wheel, and the punch is pushed to the end of the cylindrical part with a predetermined processing force. A first step in which a swiveling motion is generated in the caulking tool by rotating a main shaft that coincides with the axis of the hub wheel, and the caulking part is formed by plastic deformation; A punch having a tooth profile for plastic processing of the face spline from the peripheral edge to the outer peripheral portion thereof, and a swing shaft on which the punch is fitted, a caulking tool is inserted into the hub wheel, and the punch is Since it has a second step in which the face spline is formed by plastic deformation by pressing the end portion of the crimping portion with a predetermined processing force and generating a swinging motion in the crimping tool by rotating the spindle. , The hardness of the tooth part of the face spline can be increased, the mechanical strength of the tooth part is improved to prevent the occurrence of cracks, and the wear resistance is improved to prevent rattling of the engaging part and For wheels with improved service life It is possible to provide a processing method for receiving device. Further, since the caulking portion and the face spline are formed in two stages, the degree of plastic deformation does not increase, and the formability of the tooth portion can be improved, so that the accuracy can be improved.

  Preferably, when the face spline is molded, if the crimping portion is preliminarily heated at 150 ° C. or less by high-frequency induction heating when forming the face spline, a microcrack is formed during the processing. And the like, and the formability of the face spline can be improved.

  Further, the invention according to claim 3 improves the mechanical strength and wear resistance of the tooth part if the hardness of the tooth part of the face spline is set to be 10 points or more higher than the material hardness in HRC. be able to.

  In the invention according to claim 4, if the hardness of the tooth portion of the face spline is set to 32 HRC or more, the mechanical strength and wear resistance of the tooth portion can be improved, and the service life is extended. be able to.

  According to a fifth aspect of the present invention, the hub wheel is mounted on the vertical type with the outer side surface of the wheel mounting flange in contact with a base on which a plurality of knock pins are erected. If the knock pin is inserted and inserted into the insertion hole of the hub bolt that is press-fitted into the wheel mounting flange, the hub ring is supported and fixed on the base without newly providing a fixing means. Can do.

  Further, as in the invention described in claim 6, arcuate surfaces having predetermined curvature radii Ri and Ro are formed on both sides at a depth of 0.5 to 1.0 mm on the outer peripheral surface of the cylindrical portion of the small diameter stepped portion. An annular groove is formed, and the radius of curvature Ri of the inner-side arc surface of these arc surfaces is smaller than the radius of curvature Ro of the outer-side arc surface, and Ri ≦ Ro is set. If it is formed on the chamfered part from the inner side than the position corresponding to the large-diameter end of the inner raceway surface in the inner ring and beyond the large end surface by a predetermined dimension, the cylindrical part will be deformed during caulking. It becomes easy and the deformation | transformation of the inner ring | wheel by crimping process can be suppressed.

  Preferably, as in the invention according to claim 7, the chamfered portion of the inner ring has an arc surface having a predetermined radius of curvature r1, and the inner side arc surface of the annular groove has a radius of curvature that is greater than the radius of curvature r1. If the radius of curvature Ri is set so as to satisfy r1 ≦ Ri, damage such as cracks due to caulking can be prevented and deformation of the inner ring can be suppressed.

  The processing method of the wheel bearing device according to the present invention integrally includes an outer member in which a double row outer rolling surface is integrally formed on the inner periphery, and a wheel mounting flange for mounting the wheel at one end. A hub ring having a cylindrical small-diameter step portion extending in the axial direction on the outer periphery, and at least one inner ring press-fitted into the small-diameter step portion of the hub ring, and facing the outer rolling surface of the double row An inner member formed with a double row inner rolling surface; and a double row rolling element that is slidably accommodated between the inner member and the rolling surface of the outer member. The inner ring is fixed in the axial direction by a caulking portion formed by plastically deforming a small-diameter step portion of the outer diameter in a radially outward direction, and a face spline for torque transmission is formed on an end surface of the caulking portion. In the processing method of the bearing device, the end portion of the small diameter step portion is previously cylindrical before plastic processing. The caulking tool is formed at the center of one end surface with a nose projecting into the end of the cylindrical part with a predetermined inclination angle with respect to the inner diameter of the cylindrical part. A punch formed in a shape for plastic working the caulking portion from the periphery to the outer peripheral portion, and the punch cannot be rotated so that the phase does not shift with respect to the hub wheel during caulking. A pivot shaft that is fitted and has a central axis that gives a predetermined inclination angle with respect to the axis of the hub wheel, the caulking tool is caused to enter the hub wheel, and the punch is inserted into an end of the cylindrical portion. And a pressing motion is generated on the caulking tool by rotating the main shaft that coincides with the axis of the hub wheel, and the caulking portion is formed by plastic deformation. 1 step and the caulking tool extends from the periphery of the nose part to the outer periphery part. A punch having a tooth profile for plastic processing of the line, and the swing shaft to which the punch is fitted, the caulking tool is inserted into the hub wheel, and the punch is moved to an end of the caulking portion. And a second step in which the face spline is formed by plastic deformation by causing the caulking tool to oscillate by rotating the main shaft while pressing against the part with a predetermined processing force. Can increase the hardness of the spline teeth, improve the mechanical strength of the teeth to prevent cracks, and improve wear resistance to prevent backlash of the engaging parts, thereby improving reliability and life An improved method for processing a wheel bearing device can be provided. Further, since the caulking portion and the face spline are formed in two stages, the degree of plastic deformation does not increase, and the formability of the tooth portion can be improved, so that the accuracy can be improved.

It is a longitudinal section showing one embodiment of a wheel bearing device concerning the present invention. It is explanatory drawing which shows the manufacturing process of the crimping part of FIG. (A) is the principal part enlarged view of FIG. 2, (b) is the principal part enlarged view of (a). It is explanatory drawing which shows the state of rocking caulking. It is explanatory drawing which shows the process process of the face spline of FIG. It is explanatory drawing which shows the manufacturing process of the crimping part of the conventional wheel bearing apparatus.

  An outer member integrally having a vehicle body mounting flange to be attached to the suspension device on the outer periphery, a double row outer rolling surface formed integrally on the inner periphery, and a wheel mounting flange for attaching a wheel to one end A hub wheel formed on the outer periphery with one inner rolling surface facing the outer rolling surface of the double row, and a cylindrical small diameter step portion extending in the axial direction from the inner rolling surface, An inner member comprising an inner ring that is press-fitted into a small-diameter step portion of the hub ring and has an outer ring formed on the outer periphery thereof that faces the outer rolling surface of the double row, and the inner member and the outer member. The inner ring is formed by a caulking portion formed by plastically deforming a small-diameter step portion of the hub wheel radially outward. A face spline for torque transmission is formed on the end face of the crimped part. In the wheel bearing device processing method, the end portion of the small diameter step portion is formed in advance in the cylindrical portion before plastic working, and a caulking tool is formed at the center portion of the one end surface with respect to the inner diameter of the cylindrical portion. A punch formed in a shape for plastic processing of the caulking portion from the peripheral edge of the nose portion to the outer peripheral portion with a predetermined inclination angle projecting to the end portion of the cylindrical portion. The punch is non-rotatably fitted so that its phase does not shift with respect to the hub wheel during caulking, and the central axis is given a predetermined inclination angle with respect to the axis of the hub wheel. A swing shaft is provided, the caulking tool enters the hub wheel, the punch is pressed against the end of the cylindrical portion with a predetermined processing force, and the main shaft that matches the axis of the hub wheel is rotated. As a result, a swinging motion is generated in the caulking tool, and the caulking portion is caused by plastic deformation. A first step to be formed; a punch in which a caulking tool is formed with a tooth profile for plastic working of the face spline from the periphery of the nose portion to the outer periphery; and the punch is fitted to the punch An oscillating shaft is provided, the caulking tool is advanced into the hub wheel, the punch is pressed against the end of the caulking portion with a predetermined processing force, and the main shaft is rotated to the caulking tool. A second step is provided in which the face spline is formed by plastic deformation by generating a swinging motion. When the face spline is formed, the crimping portion is heated after being heated at 150 ° C. or less by high-frequency induction heating in advance. It is tightened.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing an embodiment of a wheel bearing device according to the present invention, FIG. 2 is an explanatory view showing a machining process of the caulking portion of FIG. 1, and FIG. FIG. 4 is an explanatory view showing a state of swing caulking, and FIG. 5 is an explanatory view showing a processing process of the face spline in FIG. It is. 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).

  The wheel bearing device shown in FIG. 1 has a so-called third generation configuration in which a hub wheel 1, a double row rolling bearing 2 and a constant velocity universal joint 3 are detachably unitized. The double-row rolling bearing 2 includes an outer member 4, an inner member 5, and double-row rolling elements (balls) 6 and 6.

  The outer member 4 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 4b for mounting to a vehicle body (not shown) on the outer periphery. The double row outer rolling surfaces 4a, 4a are integrally formed. Then, at least the double row outer raceway surfaces 4a and 4a are subjected to a hardening process in a range of 58 to 64 HRC by induction hardening.

  On the other hand, the inner member 5 is formed with double-row inner rolling surfaces 1a and 7a facing the outer rolling surfaces 4a and 4a of the outer member 4 described above. Of these double-row inner rolling surfaces 1a and 7a, 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 7a is on the outer periphery of the inner ring 7. It is integrally formed. In this case, the inner member 5 refers to the hub wheel 1 and the inner ring 7. And the double row rolling elements 6 and 6 are accommodated between these both rolling surfaces, respectively, and are hold | maintained by the holder | retainers 8 and 8 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 4 and the inner member 5, 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.

  The hub wheel 1 integrally has a wheel mounting flange 9 for attaching a wheel (not shown) to an end portion on the outer side, an inner rolling surface 1a on the outer periphery, and an axial direction from the inner rolling surface 1a. An extending cylindrical small-diameter step portion 1b is formed. The inner ring 7 is press-fitted into the small-diameter step portion 1b through a predetermined scissors. Hub bolts 9 a for fixing the wheels are planted at the circumferentially equidistant positions of the wheel mounting flanges 9. The inner ring 7 is applied to the hub wheel 1 in a state where a predetermined bearing preload is applied by a crimping portion 10 formed by plastically deforming an end portion of the small diameter step portion 1b of the hub wheel 1 radially outward. Are fixed in the axial direction.

  The hub wheel 1 is made of medium-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 1b from the seal land portion where the outer seal 11 is in sliding contact. Predetermined curing treatment is performed in the range of 58 to 64 HRC by induction hardening in the range.

  The inner ring 7 is made of high carbon chrome bearing steel such as SUJ2, and is hardened in a range of 58 to 64 HRC up to the core part by quenching. Moreover, the rolling element 6 consists of high carbon chromium bearing steel, such as SUJ2, and is hardened in the range of 62-67HRC to a core part by submerged hardening. As a result, the seal land that is the base of the wheel mounting flange 9 not only has improved wear resistance, but also has sufficient mechanical strength against the rotational bending load applied to the wheel mounting flange 9. 1 durability is improved. Further, fretting wear that occurs in the small-diameter step portion 1b that becomes the fitting surface of the inner ring 7 can be minimized.

  Here, the wheel bearing device having the third generation structure in which the inner raceway surface 1a is directly formed on the outer periphery of the hub wheel 1 is illustrated. However, the present invention is not limited to this. For example, a pair of inner rings is provided on the hub wheel. A wheel bearing device having a press-fitted second generation structure may be used. Moreover, although the double row angular contact ball bearing which used the ball for the rolling element 6 was illustrated, the double row tapered roller bearing which used the tapered roller for the rolling element 6 may be sufficient.

  The constant velocity universal joint 3 includes an outer joint member 13, a joint inner ring 14, a cage 15, and a torque transmission ball 16. The outer joint member 13 has a cup-shaped mouth portion 17 and a shoulder portion 18 that forms the bottom portion of the mouth portion 17, and a female screw 18 a is formed at the radial center portion of the shoulder portion 18. In addition, curved track grooves 17 a and 14 a extending in the axial direction are formed on the inner periphery of the mouse portion 17 and the outer periphery of the joint inner ring 14, respectively. The outer joint member 13 is made of medium-high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and the joint inner ring 14 is made of case-hardened steel such as SCr420, and the shoulders including the track grooves 17a and 14a. The outer peripheral surface of 18 is hardened by induction hardening or carburizing and quenching to a surface hardness of 58 to 64 HRC.

  In the present embodiment, a face spline 19 is formed on the end surface of the caulking portion 10, and a face spline 20 that meshes with the face spline 19 of the caulking portion 10 on the end surface of the shoulder portion 18 of the outer joint member 13 is formed by plastic working. Is formed. The opposing face splines 19 and 20 are pressed against and supported by a fixing bolt 21 screwed into the female screw 18a of the shoulder portion 18, and the hub wheel 1 and the outer joint member 13 are coupled so as to be separable in the axial direction. .

Next, the processing method of the crimping part 10 of FIG. 1 is demonstrated using FIG. 2 thru | or FIG.
As shown in FIG. 2, the hub wheel 1 is placed vertically on a base 23 on which a plurality of knock pins 22 are erected, with the outer side surface 9 b of the wheel mounting flange 9 abutting on the base wheel 23. The knock pin 22 is fitted and inserted into the insertion hole 24 of the hub bolt 9a that is press-fitted into the wheel mounting flange 9 so as to be supported and fixed. Thereby, the hub wheel 1 can be supported and fixed on the base 23 without newly providing a fixing means.

  Further, the caulking portion 10 formed by plastic working has a portion that becomes the caulking portion 10 formed in advance in the cylindrical portion 30 before plastic working. As shown in FIG. 3 in an enlarged manner, an annular groove 31 having a depth δ on the outer peripheral surface of the cylindrical portion 30 and an arc surface having curvature radii Ri and Ro is formed on both sides. Thereby, the cylindrical part 30 becomes easy to deform | transform at the time of caulking, and it can prevent that an excessive stress generate | occur | produces in the inner ring | wheel 7 and deform | transforms. However, the annular groove 31 extends from the inner side to the chamfered portion 7c of the inner ring 7 from the position corresponding to the large-diameter end of the inner rolling surface 7a in the inner ring 7, and is formed in a range exceeding the dimension c from the large end surface 7b. ing. As the width of the annular groove 31 increases, the hoop stress decreases. However, if the width of the annular groove 31 is too large, not only the inner ring pushing amount is insufficient and a predetermined inner ring fixing force cannot be obtained, but also the strength and rigidity of the hub ring 1 are decreased. Connection is not preferable.

  The depth δ of the annular groove 31 is set in the range of 0.5 to 1.0 mm. This is because when the depth δ is smaller than 0.5 mm, the effect is reduced, and when the depth δ exceeds 1.0 mm, the strength of the crimped portion 10 may be insufficient. Further, the curvature radius Ri of the inner arc surface 31a is set to be larger than the curvature radius r1 of the chamfered portion 7c of the inner ring 7 and smaller than the curvature radius Ro of the outer arc surface 31b (r1 ≦ Ri ≦ Ro). Ri is set in a range of 1 to 10 mm. Thereby, the cylindrical part 30 becomes easy to deform | transform at the time of caulking, and the deformation | transformation of the inner ring 7 by caulking can be suppressed.

  If the radius of curvature r1 of the chamfered portion 7c of the inner ring 7 is set to be smaller than 1.0 mm, stress concentration occurs at the base portion of the caulking portion 10 when a bending moment load is applied to the device during operation of the vehicle. There is a risk of damage such as microcracks. On the contrary, if the radius of curvature r1 exceeds 2.5 mm, when the cylindrical portion 30 is plastically deformed, the inner ring 7 is pushed outward in the radial direction, and an excessive hoop stress is generated in the outer diameter of the inner ring 7. It is not preferable.

  As shown in FIG. 2, the caulking tool 25 in the first step includes a punch 27 having a nose portion 26 projecting from a central portion of one end face, and a center axis A with respect to the axis L of the hub wheel 1. And an oscillating shaft 28 provided with the inclination angle α. The punch 27 is non-rotatably fitted to the swing shaft 28 by means such as a key so that the phase does not shift with respect to the hub wheel 1 during caulking. Here, the inclination angle α is set in a range of 4 to 6 °.

  The nose portion 26 of the punch 27 is formed so as to abut the end portion of the cylindrical portion 30 with a predetermined inclination angle β with respect to the inner diameter 30 a of the cylindrical portion 30. Here, the inclination angle β is set in the range of 15 to 35 °.

  Here, as shown in FIG. 4, the caulking tool 25 is advanced into the cylindrical portion 30 of the hub wheel 1, the punch 27 is pressed against the end of the cylindrical portion 30 with a predetermined processing force, and the shaft of the hub wheel 1 is By rotating a main shaft (not shown) coinciding with the center L, a swiveling motion is generated in the caulking tool 25, and the caulking portion 10 is formed by plastic working.

  While the material hardness of the cylindrical portion 30 that becomes the crimping portion 10 is in the range of 19 to 22 HRC, the surface hardness of the crimping portion 10 formed by plastic working increases to 30 to 32 HRC due to its work hardening. Yes.

  In the present embodiment, after this caulking process, two-stage caulking for forming the face spline 19 as the second step is performed. Specifically, as shown in FIG. 5, the crimping tool 29 has a nose portion 26 projecting from the central portion of one end surface, and the face spline 19 is plasticized from the periphery of the nose portion 26 to the outer peripheral portion. A punch 33 in which a tooth profile 32 for machining is formed, and a swing shaft 28 having a central axis A with a predetermined inclination angle α with respect to the axis L of the hub wheel 1 are provided.

  Then, the caulking tool 29 is advanced into the caulking portion 10 of the hub wheel 1, the punch 33 is pressed against the end portion of the caulking portion 10 with a predetermined processing force, and the main shaft coincides with the axis L of the hub wheel 1. By rotating (not shown), a swinging motion is generated in the crimping tool 29, and the face spline 19 is formed on the end surface of the crimping portion 10 by plastic working.

When the face spline 19 is formed, the crimping portion 10 is preliminarily heated by high-frequency induction heating in the range of room temperature to recrystallization temperature, specifically in the range of room temperature to 150 ° C., and then crimped. Thereby, generation | occurrence | production of a micro crack etc. can be prevented at the time of a process, and the moldability of the face spline 19 can be improved. As used herein, “recrystallization” refers to the process of reducing the internal stress when a crystal that has undergone plastic strain by cold working or the like is heated, and then from the original crystal grains in which strain remains. This is a phenomenon in which new crystal nuclei with no internal strain are generated and the number of nuclei grows gradually, and each nuclei grows gradually and replaces the original crystal grains. The recrystallization temperature is a temperature at which recrystallization occurs, and is significantly influenced by the purity or composition of metals and alloys, the degree of plastic strain in the crystal, the heating time, and the like. Therefore, when the heating temperature exceeds 150 ° C., the moldability can be further improved. On the other hand, not only the heating time is prolonged and the working efficiency is lowered, but also the heat influence on the rubber material of the grease and the seal and the inner ring It is not preferable because there is temper softening.

  The surface hardness of the face spline 19 by the two-step caulking in the second step is increased to 32 to 40 HRC, while the surface hardness of the caulking portion 10 formed by plastic working in the first step is 30 to 32 HRC. . When the crimping portion and the face spline are simultaneously crimped as in the prior art, the surface hardness is 29 to 37 HRC, whereas when the face spline is formed by two-stage crimping as in the present invention, the HRC3 Increased point hardness.

  The two-step caulking composed of the first step and the second step, that is, the caulking portion 10 is formed in the first step, and the face spline 19 is plastically formed on the end surface of the caulking portion 10 in the second step. Since it is formed, the hardness of the tooth part of the face spline 19 can be increased, the mechanical strength of the tooth part is improved to prevent the occurrence of cracks, and the wear resistance is improved to reduce the backlash of the engaging part. Thus, it is possible to provide a method for processing a wheel bearing device in which reliability and life are improved. Further, since the crimped portion 10 and the face spline 19 are formed in two stages, the degree of plastic deformation does not increase and the formability of the tooth portion can be improved, so that the accuracy can be improved.

  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.

  A bearing device for a driving wheel according to the present invention is a wheel bearing in which a bearing portion having a hub wheel and a constant velocity universal joint are connected via a face spline so that torque can be transmitted, and both are detachably unitized by screw means. It can be applied to the device.

DESCRIPTION OF SYMBOLS 1 Hub wheel 1a, 7a Inner rolling surface 1b Small diameter step part 2 Double row rolling bearing 3 Constant velocity universal joint 4 Outer member 4a Outer rolling surface 4b Car body mounting flange 5 Inner member 6 Rolling body 7 Inner ring 7b Large end surface 7c Chamfered portion 8 Cage 9 Wheel mounting flange 9a Hub bolt 9b Outer side surface 10 Clamping portion 11, 12 Seal 13 Outer joint member 14 Joint inner ring 14a, 17a Track groove 15 Cage 16 Torque transmission ball 17 Cup portion 18 Shoulder portion 18a Female thread 19, 20 Face spline 21 Fixing bolt 22 Knock pin 23 Base 24 Insertion hole 25, 29 Clamping tool 26 Nose part 27, 33 Punch 28 Oscillating shaft 30 Cylindrical part 30a Cylindrical inner diameter 31 Annular groove 32 Tooth profile 51 Hub wheel 51a, 57a Inner rolling surface 51b Small diameter step 52 Double row rolling bearing 53 Face spline 54 Outer member 54a Outer rolling surface 54b Car body mounting flange 55 Inner member 56 Ball 57 Inner ring 58 Cage 59 Wheel mounting flange 59b Side surface 60 of the wheel mounting flange Clamping portion 61, 62 Seal 63 Knock pin 64 Base 65 Insertion hole 66 Cylindrical portion 66a Inner diameter 67 of cylindrical part 68 Nose part 69 Tooth shape 70 Punch 71 Oscillating axis A Center axis c of the oscillating axis L Dimension from large end surface of inner ring of annular groove L Center axis of hub ring r1 Curvature of chamfered part of inner ring Radius r2 Curvature radius Ri of the circular groove of the annular groove Radius of curvature Ro of the inner arc surface of the annular groove Ro Curvature radius of the outer circular surface of the annular groove α Inclination angle β of the oscillating shaft δ Inclination angle δ of the nose Depth of

Claims (7)

An outer member in which a double row outer rolling surface is integrally formed on the inner periphery;
A hub wheel integrally having a wheel mounting flange for mounting a wheel at one end and having a cylindrical small-diameter step portion extending in the axial direction on the outer periphery, and at least one press-fitted into the small-diameter step portion of the hub ring An inner member formed of two inner rings and formed with a double-row inner rolling surface facing the double-row outer rolling surface;
A double row rolling element housed in a freely rollable manner between the inner member and the rolling surface of the outer member,
The inner ring is fixed in the axial direction by a caulking portion formed by plastically deforming a small-diameter step portion of the hub wheel radially outward,
In the processing method of the wheel bearing device in which a face spline for torque transmission is formed on the end face of the crimped portion,
The end of the small diameter step is formed in the cylindrical portion in advance before plastic working,
A crimping tool has a nose projecting at the central portion of one end face with a predetermined angle of inclination with respect to the inner diameter of the cylindrical portion and projecting from the periphery of the nose to the outer peripheral portion. And a punch formed with a shape for plastic working the caulking portion,
This punch is non-rotatably fitted so that its phase does not shift with respect to the hub wheel during caulking, and the center axis is swung with a predetermined inclination angle with respect to the axis of the hub ring. With a shaft,
The caulking tool enters the hub wheel, the punch is pressed against the end of the cylindrical portion with a predetermined processing force,
A first step in which a swiveling motion is generated in the caulking tool by rotating a main shaft coinciding with an axis of the hub wheel, and the caulking portion is formed by plastic deformation;
A punch in which a caulking tool is formed with a tooth profile for plastic working the face spline from the periphery of the nose to the outer periphery,
The swing shaft to which this punch is fitted is provided,
The caulking tool enters the hub wheel, the punch is pressed against the end of the caulking portion with a predetermined processing force,
A processing method for a wheel bearing device, comprising: a second step in which a swinging motion is generated in the caulking tool by rotating the main shaft, and the face spline is formed by plastic deformation.   The method for processing a wheel bearing device according to claim 1, wherein, when the face spline is formed, the crimping portion is preliminarily heated after being heated at 150 ° C. or less by high-frequency induction heating.   The processing method of the wheel bearing device according to claim 1 or 2, wherein the hardness of the tooth portion of the face spline is set to be higher by 10 points or more in HRC than the material hardness.   The wheel bearing device machining method according to any one of claims 1 to 3, wherein the hardness of the tooth portion of the face spline is set to 32 HRC or more.   The hub wheel is vertically mounted on a base on which a plurality of knock pins are erected, with the outer side surface of the wheel mounting flange in contact with the hub bolt, and a hub bolt that is press-fitted into the wheel mounting flange. The processing method of the wheel bearing device according to claim 1, wherein the knock pin is supported and fixed by being inserted into the insertion hole.   An annular groove having a circular arc surface having a predetermined radius of curvature Ri and Ro is formed on both sides at a depth of 0.5 to 1.0 mm on the outer peripheral surface of the cylindrical portion of the small-diameter stepped portion. The radius of curvature Ri of the arc surface on the side is smaller than the radius of curvature Ro of the arc surface of the outer side, and Ri ≦ Ro is set, and the annular groove corresponds to the large diameter end of the inner raceway surface in the inner ring. The wheel bearing device machining method according to claim 1, wherein the wheel bearing device is formed in a range from the inner side to the chamfered portion with respect to the position and beyond a predetermined dimension from the large end surface.   The chamfered portion of the inner ring has an arc surface having a predetermined radius of curvature r1, and the radius of curvature Ri of the inner side arc surface of the annular groove is larger than the radius of curvature r1, and is set to satisfy r1 ≦ Ri. The processing method of the wheel bearing apparatus of Claim 6 currently performed.

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