JP2018079824A - Wheel bearing spline processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wheel bearing spline processing method by which a highly-accurate female spline having a reduced phase shift between itself and a guide spline can be formed while suppressing an increase in a cost of manufacture.SOLUTION: A wheel bearing has: an outward member 5 on an inner peripheral surface of which outside raceway surfaces of plural rows are formed; an inward member 1, 2 on an outer peripheral surface of which inside raceway surfaces of plural rows, which are opposite to the outside raceway surfaces, are formed; rolling elements of plural rows 3, 4 which are interposed between the outside raceway surfaces of the outward member and the inside raceway surfaces of the inward member; and holders 15, 16 which hold the rolling elements. A spline 39 with an interference is formed on an inner periphery of the inward member 1, 2, and a guide spline 44 is formed on an inboard side end part of the spline with the interference. The spline 39 with the interference and the guide spline 44 are formed on an intermediate component 1' of the inward member by slotter processing with use of a slotter tool 80 which has a first cutting blade 81 corresponding to the spline 39 with the interference, and a second cutting blade 82 corresponding to the guide spline 44.SELECTED DRAWING: Figure 11

Description

  The present invention relates to a spline processing method for a wheel bearing.

  For example, as a wheel bearing device that rotatably supports a driving wheel (front wheel of FF vehicle, rear wheel of FR vehicle, all wheels of 4WD vehicle) with respect to a suspension system of an automobile, the hub wheel of the wheel bearing has a constant velocity. A wheel bearing device that can be separated from an outer joint member of a universal joint and has excellent maintainability has been proposed (Patent Document 1).

  The wheel bearing device described in Patent Document 1 has an outer member having a double row outer raceway surface formed on the inner circumference, and a double row inner raceway surface facing the outer raceway surface on the outer circumference. A wheel bearing comprising: an inner member comprising a ring and an inner ring; and a double row rolling element interposed between an outer raceway surface of the outer member and an inner raceway surface of the inner member. This is a wheel bearing device in which the constant velocity universal joint is separably coupled to the wheel bearing by a screw tightening structure by fitting the stem portion of the outer joint member of the constant velocity universal joint to the inner diameter of the hub ring of A plurality of convex portions (male splines) formed in the stem portion of the joint member extending in the axial direction are press-fitted into a hub wheel formed with a plurality of concave portions (female splines) having a tightening margin with respect to the convex portions. By transferring the shape of the convex part to the ring, the fitting contact part between the convex part and the concave part Constitute a recess-projection fitting structure throughout are in close contact.

  In the wheel bearing device described above, by the female screw portion formed at the shaft end of the stem portion of the outer joint member, and the bolt that is locked to the seat surface of the inner wall of the hub wheel while being screwed to the female screw portion, A screw tightening structure is configured.

  In the wheel bearing device described above, since the female spline having a tightening margin with respect to the male spline formed on the stem portion of the outer joint member is formed in advance on the hub wheel, the mating contact between the male spline and the female spline It is possible to reduce the press-fit load for close contact with the entire region, and to make it possible to press-fit the outer joint member to the hub wheel with less than the axial force generated by tightening the bolt when the vehicle is assembled by an automobile manufacturer. Have advantages.

  The forming of the female spline of the hub wheel has been conventionally performed by broaching as a cutting process. In addition, a highly accurate female spline forming technique to the shaft inner diameter by press working has been proposed (Patent Document 2).

JP2013-233842A JP 2009-172663 A

  However, in the case of the wheel bearing of Patent Document 1, a seat surface of a bolt for drawing the outer joint member of the constant velocity universal joint into the hub wheel is provided on the inner wall of the hub wheel. For this reason, the broach tool cannot be pulled out, and broaching that has been conventionally performed cannot be employed.

  In the wheel bearing described above, a female spline into which the stem portion of the outer joint member is press-fitted into the inner peripheral surface of the hub wheel and an insertion guide for press-fitting the stem portion formed at one end of the female spline. A two-stage spline consisting of a plurality of guide splines is formed. Such a two-stage spline is difficult to form by a method of drawing a spline mandrel as in Patent Document 2.

  Furthermore, the female spline needs to be in phase with the guide spline. However, because the spline module (reference circle diameter / number of teeth) is small, in the two-step molding in which guide spline molding is performed separately after female spline molding, It turned out to be difficult to match the phases.

  In addition, it has been found that it is necessary to increase the accuracy of the female spline in order to satisfy the tightening allowance (press fit allowance) of the female spline in the entire fitting contact portion of the stem portion of the hub wheel and the outer joint member.

  In view of the above problems, an object of the present invention is to provide a spline processing method for a wheel bearing capable of forming a high-precision female spline in which a phase shift with a guide spline is reduced while suppressing an increase in manufacturing cost. And

  As a result of various investigations to achieve the above object, the present inventor conducted slotting using a slotter tool having a cutting blade corresponding to a female spline (tightening spline) and a cutting blade corresponding to a guide spline. The idea was to form both splines.

  As technical means for achieving the above-mentioned object, the present invention comprises an outer member having a double row outer raceway surface formed on an inner peripheral surface, and an inner side of the double row facing the outer raceway surface on an outer peripheral surface. An inner member formed with a raceway surface, a double row rolling element interposed between an outer raceway surface of the outer member and an inner raceway surface of the inner member, and a holding for holding the rolling element In the spline processing method for a wheel bearing, wherein a spline for tightening is formed on the inner periphery of the inner member, and a guide spline is formed at an inboard side end of the tightening spline. Forming a spline with a tightening margin and a guide spline by slotter processing using a slotter tool having a first cutting blade corresponding to a tightening spline and a second cutting blade corresponding to a guide spline on an intermediate part of a square member To do And features.

  In slotting, grooving is basically performed by feeding one cutting blade (bite) in one direction. Therefore, when the tool is fed in the axial direction on the inner periphery of the intermediate part of the hub wheel, the grooving can be completed before the tool interferes with the inner wall. In addition, by providing the slotter tool with a first cutting blade corresponding to the tightening spline and a second cutting blade corresponding to the guide spline, the tightening spline and the guide spline can be moved simultaneously with a single tool feed. Can be processed. Accordingly, it is possible to prevent the phase shift between the tightening spline and the guide spline and to improve the accuracy of the spline. At this time, the phase alignment work of both the splines is not necessary, so that an increase in manufacturing cost can be prevented.

  Formed by cutting with the first cutting blade by forming the first relief portion for releasing the first cutting blade on the outboard side of the intermediate part of the inner member on the outboard side from the region where the fastening spline is formed The cut chips can be naturally separated from the intermediate parts.

  Further, a second relief portion for allowing the second cutting blade to escape at the boundary between the first region where the fastening spline is formed and the second region where the guide spline is formed, of the intermediate part of the inner member By forming, the chips formed by cutting with the second cutting blade can be naturally separated from the intermediate part. Therefore, the chip removal step can be omitted.

  ADVANTAGE OF THE INVENTION According to this invention, the highly accurate female spline which made small the phase shift between guide splines, suppressing the increase in manufacturing cost can be formed.

It is a longitudinal cross-sectional view which shows the state which assembled | attached the wheel bearing and constant velocity universal joint based on the spline processing method of the wheel bearing which concerns on embodiment of this invention. It is a longitudinal cross-sectional view which shows the state before attaching the wheel bearing of FIG. 1, and a constant velocity universal joint. (A) The figure is a principal part expanded longitudinal sectional view which shows the state before pressing the stem part of an outer joint member in the hub ring of a wheel bearing, (b) A figure is the AA line of (a) figure. FIG. (A) The figure is a principal part expanded longitudinal cross-sectional view which shows the state in the middle of press-fitting the stem part of an outer joint member in the hub ring of a wheel bearing, (b) is a BB line of (a) figure. FIG. (A) The figure is a principal part expanded longitudinal sectional view which shows the state after pressing the stem part of an outer joint member in the hub ring of a wheel bearing, (b) is a CC line of (a) figure. FIG. It is a longitudinal cross-sectional view which shows the intermediate components of a hub ring. It is a perspective view which shows a slotter tool. It is a longitudinal cross-sectional view of a slotter tool. It is the enlarged front view which looked at the blade part provided in the cutting blade of the slotter tool from the Y direction of FIG. It is a side view which shows a spline processing apparatus. It is a longitudinal cross-sectional view which expands and shows a spline processing process. It is the front view seen from the Y direction of FIG. 7 which shows other embodiment of a slotter tool. It is a longitudinal cross-sectional view which shows other embodiment of the intermediate components of a hub ring. It is a longitudinal cross-sectional view which expands and shows the spline processing process in the intermediate part shown in FIG. It is a longitudinal cross-sectional view which shows the state before attaching a wheel bearing and a constant velocity universal joint. It is a longitudinal cross-sectional view of the wheel bearing apparatus. The hub wheel machining process is shown: (a) the material, (b) the primary turning, (c) the spline machining, (d) the secondary turning, (e) the heat treatment, (f ) Is a longitudinal sectional view showing an outline of each grinding process. It is sectional drawing which shows the spline processing method by broaching.

  Before explaining the spline processing method for a wheel bearing according to the first embodiment of the present invention, the wheel bearing obtained by the spline processing method and the constant velocity universal joint assembled to the wheel bearing are illustrated. It demonstrates based on FIGS. FIG. 1 is a longitudinal sectional view showing a state in which a wheel bearing and a constant velocity universal joint are assembled, and FIG. 2 is a longitudinal sectional view showing a state before the wheel bearing and the constant velocity universal joint are assembled.

  As shown in FIGS. 1 and 2, the wheel bearing 20 mainly includes hub wheels 1 and 2 that are inner members, double-row rolling elements 3 and 4, outer members 5, and cages 15 and 16. The configuration. The wheel bearing device is assembled by assembling the wheel bearing 20 and the constant velocity universal joint 6. In the following description, the side closer to the outside of the vehicle body is referred to as the outboard side (left side of the drawing), and the side closer to the center is referred to as the inboard side (right side of the drawing).

  The hub wheel 1 has an inner raceway surface 7 on the outboard side formed on the outer peripheral surface thereof, and includes a wheel mounting flange 9 for mounting a wheel (not shown). Hub bolts 10 for fixing the wheel and the disk are implanted at equal intervals in the circumferential direction of the wheel mounting flange 9. The inner ring 2 is fitted to the small-diameter step portion 12 formed on the inboard side outer peripheral surface of the hub wheel 1, and the inboard-side inner raceway surface 8 is formed on the outer peripheral surface of the inner ring 2.

  The inner ring 2 is press-fitted with an appropriate tightening margin to prevent creep. The outboard side inner raceway surface 7 formed on the outer peripheral surface of the hub wheel 1 and the inboard side inner raceway surface 8 formed on the outer peripheral surface of the inner ring 2 constitute a double row raceway surface. The inner ring 2 is press-fitted into the small-diameter step portion 12 of the hub wheel 1, and the end portion of the small-diameter step portion 12 is crimped to the outside, so that the inner ring 2 is prevented from being detached by the crimping portion 11 and integrated with the hub wheel 1. The preload is applied to the wheel bearing 20.

  The outer member 5 has double-row outer raceways 13 and 14 facing the inner raceways 7 and 8 of the hub wheel 1 and the inner ring 2 on the inner circumferential surface. The wheel bearing 20 is attached to the vehicle body by fixing the vehicle body mounting flange 19 of the outer member 5 to a knuckle extending from a suspension device (not shown) of the vehicle body.

  The wheel bearing 20 has a double-row angular ball bearing structure, and the inner raceway surfaces 7 and 8 formed on the outer peripheral surfaces of the hub wheel 1 and the inner ring 2 and the outer raceway surface formed on the inner peripheral surface of the outer member 5. The rolling elements 3, 4 are interposed between the rolling elements 3, 14, and the rolling elements 3, 4 in each row are supported by the cages 15, 16 at equal intervals in the circumferential direction.

  A pair of seals 17, 18 for sealing the annular space between the outer member 5, the hub wheel 1, and the inner ring 2 so as to be in sliding contact with the outer peripheral surfaces of the hub wheel 1 and the inner ring 2, at both end openings of the wheel bearing 20. Are fitted to the inner diameter surfaces of both ends of the outer member 5 to prevent leakage of grease filled inside and intrusion of water and foreign matters from the outside.

  The constant velocity universal joint 6 is provided at one end of an intermediate shaft 22 constituting the drive shaft 21 and is opposed to the outer joint member 24 having a track groove 23 formed on the inner peripheral surface thereof and the track groove 23 of the outer joint member 24. Torque transmission balls (also referred to simply as balls) incorporated between the inner joint member 26 in which the track grooves 25 are formed on the outer peripheral surface, the track groove 23 of the outer joint member 24, and the track groove 25 of the inner joint member 26. ) 27 and a cage 28 that holds the ball 27 interposed between the inner peripheral surface of the outer joint member 24 and the outer peripheral surface of the inner joint member 26.

  The outer joint member 24 includes a mouth portion 29 that accommodates an inner part composed of the inner joint member 26, a ball 27, and a cage 28, and a stem portion 30 that extends integrally from the mouth portion 29 in the axial direction. The inner joint member 26 is coupled so that torque can be transmitted by fitting the shaft end of the intermediate shaft 22 by spline fitting.

  Between the outer joint member 24 of the constant velocity universal joint 6 and the intermediate shaft 22, a resin bellows for preventing leakage of a lubricant such as grease enclosed in the joint and preventing foreign matter from entering from the outside of the joint. The boot 31 is attached and the opening of the outer joint member 24 is closed.

  As shown in FIG. 2, a male spline 37 is formed on the outer peripheral surface of the outboard side of the stem portion 30 of the outer joint member 24, and a female spline 39 is formed on the inner peripheral surface of the shaft hole 38 of the hub wheel 1. ing. The male spline 37 of the stem portion 30 of the outer joint member 24 is press-fitted into the female spline 39. The female spline 39 is a fastening spline and has a fastening allowance n with respect to the circumferential side wall portion 47 of the male spline 37 (see FIG. 4B). This tightening spline 39 means the tightening spline in the present specification and claims. In the following description, it will be referred to as a tightening spline 39. A guide spline 44 is formed at the end of the inboard side of the tightening spline 39. The guide spline 44 guides the male spline 37 at the start of press-fitting of the stem 30. The guide spline 44 has the same phase as the fastening spline 39 and is formed in a spline shape larger than the male spline 37 of the stem portion 30.

  An inner wall 43 is provided on the outboard side of the shaft hole 38 of the hub wheel 1, and a seat surface 36 of the bolt 32 and an insertion hole 35 are formed. On the other hand, a female thread portion 33 is formed at the shaft end of the stem portion 30 of the outer joint member 24. With the stem portion 30 of the outer joint member 24 fitted into the shaft hole 38 of the hub wheel 1, the male screw portion 34 of the bolt 32 is inserted into the insertion hole 35 of the inner wall 43, and the male screw portion 34 is inserted into the stem of the outer joint member 24. The outer joint member 24 is press-fitted into the hub wheel 1 by being screwed into the female thread portion 33 of the portion 30 and tightened in a state where the head portion 51 of the bolt 32 is engaged with the seat surface 36, and finally, for the wheel. The bearing 20 and the constant velocity universal joint 6 are fixed. As the material of the outer joint member 24 and the hub wheel 1, medium carbon steel for machine structure represented by S53C and the like is suitable.

  When the stem portion 30 of the outer joint member 24 is inserted into the shaft hole 38 of the hub wheel 1, the male spline 37 of the stem portion 30 is fitted into the guide spline 44 of the hub wheel 1. The hub wheel 1 can be guided so as to be securely pressed into the fastening spline 39 of the hub wheel 1 and stable press-fitting is possible, thereby preventing misalignment and tilting during press-fitting.

  The details of the process of press-fitting the stem portion of the outer joint member into the hub wheel of the wheel bearing will be described with reference to FIGS. FIG. 3A is an enlarged vertical cross-sectional view of a main part showing a state before the stem portion of the outer joint member is press-fitted into the hub wheel of the wheel bearing, and FIG. 3B is a cross-sectional view taken along line A- of FIG. It is a cross-sectional view along line A. 4 (a) is an enlarged vertical sectional view of a main part showing a state in which the stem portion of the outer joint member is being press-fitted into the hub wheel of the wheel bearing, and FIG. 4 (b) is a cross-sectional view taken along line B- in FIG. It is a cross-sectional view along line B. FIG. 5A is an enlarged vertical cross-sectional view of a main part showing a state after the stem portion of the outer joint member is press-fitted into the hub wheel of the wheel bearing, and FIG. 5B is a cross-sectional view taken along line C- of FIG. It is a cross-sectional view along line C.

  As shown in FIG. 3A, in the state where the tip of the male spline 37 of the stem portion 30 is fitted into the guide spline 44, as shown in FIG. A gap m is formed. Due to the presence of the gap m, the male spline 37 can be easily fitted to the guide spline 44 and can be guided so as to be surely press-fitted.

  Subsequently, as shown in FIG. 4A, the male spline 37 is press-fitted into the tightening spline 39. As shown in FIG. 4B, the circumferential dimension of the fastening spline 39 is set smaller than that of the male spline 37. For this reason, the tightening allowance spline 39 has an allowance n for the circumferential side wall 47 of the male spline 37 only. 2n, which is the sum of the interferences n on both sides of the tooth surface of the spline, is about 10 to 50 μm. Further, the radial dimension of the fastening spline 39 is set larger than that of the male spline 37. For this reason, there is a gap p between a portion of the male spline 37 excluding the circumferential side wall portion 47, that is, between the radial front end portion 48 of the male spline 37 and the tightening spline 39. The male spline 37 has a trapezoidal tooth shape, but may have an involute tooth shape. The module of the male spline 37 is set to be smaller than the conventional spline module 1.0 or more in the range of 0.3 to 0.75.

  As shown in FIGS. 5 (a) and 5 (b), when the stem portion 30 is press-fitted into the shaft hole 38 of the hub wheel 1, the surface of the tightening spline 39 is moved by the circumferential side wall portion 47 of the male spline 37. The shape of the circumferential side wall portion 47 of the male spline 37 is transferred to the tightening spline 39 while forming a concave surface 40 with very slight cutting and accompanying slight plastic deformation and elastic deformation. It will be. As shown in FIG. 5 (a), the protruding portion 45 generated by the above transfer is held in the accommodating portion 46, so that the removal processing of the protruding portion 45 becomes unnecessary, reducing the work man-hours and workability. Improvement and cost reduction can be achieved. The surface hardness of the male spline 37 is preferably larger than the surface hardness of the tightening spline 39. For example, the difference between the surface hardness of the male spline 37 and the surface spline 39 is 20 or more in HRC. The surface hardness of the male spline 37 is preferably HRC 50 to 65, and the surface hardness of the fastening spline 39 is preferably HRC 10 to 30.

  At the time of press-fitting, the circumferential side wall 47 of the male spline 37 bites into the tightening spline 39 so that the inner diameter of the hub wheel 1 is slightly expanded, and the axial direction relative to the male spline 37 is increased. Movement is allowed. When the axial relative movement of the male spline 37 stops, the shaft hole 38 of the hub wheel 1 is reduced in diameter to return to the original diameter. Accordingly, the male spline 37 and the concave contact surface 40 of the tightening spline 39 are brought into close contact with each other in the entire contact area X, and the outer joint member 24 and the hub wheel 1 can be firmly coupled and integrated.

  Since it is a press-fit state as described above, a large press-fit load is not required. Therefore, when the vehicle manufacturer assembles the vehicle, after attaching the wheel bearing 20 to the knuckle extending from the suspension device of the vehicle body, the outer side of the shaft hole 38 of the hub wheel 1 is pulled by the pulling force by the bolt 32 for fastening and fixing. The stem portion 30 of the joint member 24 can be press-fitted, and the constant velocity universal joint 6 can be easily assembled to the wheel bearing 20. As a result, the work in assembling to the vehicle body is improved, and the assembly It is possible to prevent damage to parts at the time.

  The overall configuration of the wheel bearing and the constant velocity universal joint is as described above. Next, the spline processing method of the wheel bearing concerning the 1st Embodiment of this invention is demonstrated based on FIGS. The wheel bearing spline processing method of this embodiment is a slotter processing using a slotter tool 80 having a first cutting blade 81 corresponding to the tightening spline 39 and a second cutting blade 82 corresponding to the guide spline 44. By forming the tightening spline and the guide spline at the same position in the circumferential direction, the tightening spline 39 and the guide spline 44 can be accurately formed even in the situation where the inner wall 43 exists. It is characterized by.

  First, the intermediate part 1 'of the hub wheel 1 will be described with reference to FIG. FIG. 6 is a longitudinal sectional view showing the intermediate part 1 ′ of the hub wheel 1. The intermediate part 1 ′ of the hub wheel 1 is formed by turning or drilling a forged material into a wheel mounting flange 9, an outboard side inner raceway surface 7 ′, a small diameter step portion 12 ′, a shaft hole 38, and a spline. The inner peripheral surface 50, the escape portion 52, the insertion hole 35, the hub bolt hole (not shown), and the like are machined. The escape portion 52 has an inner diameter larger than the inner diameter of the spline-forming inner peripheral surface 50 with an appropriate size. Details of the operation of the escape portion 52 will be described later.

  Next, the slotter tool 80 used for spline processing will be described with reference to FIGS. 7 is a perspective view showing a schematic configuration of the slotter tool, FIG. 8 is a longitudinal sectional view of the slotter tool, and FIG. 9 is an enlarged view of the blade portion of the cutting blade provided in the slotter tool as viewed from the Y direction in FIG. It is a front view.

  As shown in FIG. 7, the slotter tool 80 includes a first cutting blade 81 and a second cutting blade 82, and a stepped cylindrical holding member 83 that holds the two cutting blades 81 and 82.

  The first cutting blade 81 and the second cutting blade 82 integrally include base portions 81a and 82a and projecting portions 81b and 82b that project from the base portions 81a and 82a in the direction of the outer diameter side of the holding member 83. . The protrusion 81b of the first cutting blade 81 has a shape corresponding to the tooth gap of the tightening spline 39 (see FIG. 2), and the protrusion 82b of the second cutting blade 82 is the guide spline 44 (see FIG. 2). ). Diagonal edges formed on both sides of the tip surfaces of the projecting portions 81b and 82b constitute blade portions 811 and 821 for cutting the counterpart material.

  The holding member 83 includes a cylindrical shaft portion 83a and a flange 83b. Two cutting blades 81 and 82 are attached to the shaft-like portion 83a so as to be separated from each other in the axial direction. At this time, the 1st cutting blade 81 is attached to the front-end | tip (end part on the opposite side to the flange 83b of the axial part 83a) of the holding member 83. FIG. The attachment structure for attaching the cutting blades 81 and 82 to the holding portion 83 is arbitrary as long as the cutting blades 81 and 82 can be attached and detached. For example, as shown in FIG. 8, the first cutting blade 81 is fitted into an attachment recess 831 that opens at the tip end surface of the shaft-like portion 83a, and at the attachment recess 832 provided in the intermediate portion of the shaft-like portion 83a. The second cutting blade 82 and the spacer 84 are accommodated, and in this state, the first cutting blade 81, the spacer 84, and the screw that passes through the second cutting blade 82 are tightened (not shown), thereby providing two cutting blades. It is conceivable to fix 81 and 82 to the shaft-shaped portion 83a.

  As shown in FIG. 9, in a state where the cutting blades 81 and 82 are attached to the holding member 83, the protruding portions 81b and 82b protrude to the outer diameter side from the outer peripheral surface 833 of the shaft-shaped portion 83a. At this time, the phases of the blade centers O of the first cutting blade 81 and the second cutting blade 82 (phase in the circumferential direction of the holding member 83) coincide with each other. The blade portion 811 of the first cutting blade 81 and the blade portion 821 of the second cutting blade 82 are different in size, and the blade portion 821 of the second cutting blade 82 is the first cutting blade 81 when viewed from the front (Y direction). It is larger than the blade portion 811. Specifically, the blade portion 821 of the second cutting blade 82 is larger in both height (vertical direction in FIG. 9) and width (horizontal direction in FIG. 9) than the blade portion 811 of the first cutting blade 81. . In FIG. 9, the protruding portion 81 b of the first cutting blade 81 and the protruding portion 82 b of the second cutting blade 82 are formed in a similar shape, but both may be formed in a non-similar shape.

FIG. 10 is a side view of a spline processing apparatus that performs spline processing using the slotter tool 80.
As shown in FIG. 10, the slotter tool 80 is attached to the machining head 91 by bolting the flange 83 b to the machining head 91 of the machining apparatus 90. On the other hand, the intermediate part 1 ′ of the hub wheel 1 is held by a positioning device 92 having an index function with the small-diameter step portion 12 ′ facing the processing head 91 side. The machining head 91 can reciprocate in a direction (X direction in FIG. 9) that is the radial direction of the intermediate part 1 ′ and a direction (Y direction in FIG. 9) that is the axial direction.

  As shown in FIG. 11, the slotter processing by this processing apparatus is performed by using a slotter tool 80 arranged on the inboard side of the spline-forming inner peripheral surface 50 of the intermediate part 1 ′ on the outboard side in the axial direction of the intermediate part 1 ′. It is performed by sending it toward (step I). As the slotter tool 80 is fed, the blade portion 811 (see FIG. 7) of the first cutting blade 81 bites into the spline-forming inner peripheral surface 50 of the intermediate part 1 ′ and cuts the meat of the intermediate part 1 ′ in the axial direction. Groove processing. Subsequently, the blade portion 821 (see FIG. 7) of the second cutting blade 82 bites into the groove 39 'formed by the first cutting blade 81 and cuts the surface thereof. As shown by the two-dot chain line, the slotter tool 80 is fed until the first cutting blade 81 provided at the tip of the slotter tool 80 passes through the spline-forming inner peripheral surface 50 and reaches the inner periphery of the escape portion 52. .

  As a result, a first groove 39 ′ cut by the first cutting blade 81 is formed on the outboard side of the spline forming inner peripheral surface 50, and the first cutting blade 81 is formed on the inboard side of the spline forming inner peripheral surface 50. A second groove 44 ′ that is primarily cut and then secondarily cut on the second cutting blade 82 is formed. The depth and the circumferential width of the second groove 44 'are both larger than the first groove 39'. Therefore, grooves having different cross-sectional areas can be formed in the same phase on the inboard side and the outboard side by one slotting process. When a sufficient cutting depth can be obtained by a single feed of the slotter tool 80, the spline machining is completed by a single slotter machining. Accordingly, in this case, the first groove 39 ′ is a tooth groove of the tightening spline 39, and the second groove 44 ′ is a tooth groove of the guide spline 44.

  Thereafter, the slotter tool 80 is moved to the inner diameter side of the intermediate part 1 ′ to separate the blade portions 811 and 821 from the surfaces of the grooves 39 ′ and 44 ′ (Step II). In this state, the slotter tool 80 is moved to the axial inboard side of the intermediate part 1 '(step III), and further moved to the outer diameter side of the intermediate part 1' to return to the initial position (step IV). At the same time, the intermediate device 1 ′ is rotated by one pitch by the chuck device 92 to perform indexing for the next slotting process. Thereafter, the fastening spline 39 and the guide spline 44 can be formed on the spline-forming inner peripheral surface 50 of the intermediate part 1 ′ by repeating the above procedure for all the teeth.

  When the slot depth required for the tooth grooves of both splines 39 and 44 cannot be obtained by one slotting process, the tooth grooves are formed by a plurality of slotting processes. That is, as shown by a broken line in FIG. 11, after the first slotter processing is completed, the slotter tool 80 is moved to the outer diameter side to ensure the notch with respect to the existing groove (process V). It feeds to the axial outboard side to cut the surface of the existing groove (process VI), and then retracts the slotter tool 80 to the inner diameter side (process II). Thereafter, a similar process is repeated as necessary to form a tooth gap having a necessary cutting depth.

  In the above description, as the slotter tool 80, each cutting blade 81, 82 is provided with one blade portion 811, 821, and one slot is formed by one slotting process. As shown, a plurality of (three in FIG. 12) blade portions 811 and 821 are provided on each of the first cutting blade 81 and the second cutting blade 82 so as to form a plurality of tooth grooves simultaneously by one slotting process. It may be. With such a configuration, since groove processing can be performed simultaneously at a plurality of locations in the circumferential direction of the intermediate part 1 ′, the number of times the chuck device 92 is indexed can be reduced, and the processing efficiency can be improved.

  As a general processing method for forming a female spline, as shown in FIG. 18, broaching using a broach 100 is known. However, when broaching is performed in the wheel bearing of the present invention, the hub wheel 1 Since the intermediate part 1 ′ has the inner wall 43, the broaching tool 100 cannot interfere with the inner wall 43 to perform broaching. On the other hand, in the slotter processing employed in the present invention, one groove is formed by feeding one cutting blade (bite) in one direction. Therefore, the groove machining can be completed before the tool interferes with the inner wall 43 when the tool is fed in the axial direction on the inner periphery of the intermediate part of the hub wheel. Further, since the slotter tool 80 is provided with the first cutting blade 81 corresponding to the tightening spline 39 and the second cutting blade 82 corresponding to the guide spline 44, the tightening spline 39 and the guide spline 44 are provided. Can be processed simultaneously. Accordingly, it is possible to suppress the phase shift between the tightening spline 39 and the guide spline 44 and prevent the tightening n (see FIG. 4B) from becoming non-uniform due to the phase shift between them. Accordingly, it is possible to securely bring the entire contact area of the male spline 37 and the concave surface 40 of the tightening spline 39 into close contact. Further, since the phase alignment work of both the splines 39 and 44 by post-processing is not required, it is possible to prevent an increase in manufacturing cost.

  As shown in FIG. 6, a relief portion 52 (first relief portion) is formed on the outboard side of the spline-forming inner peripheral surface 50, and the inner diameter dimension of the relief portion 52 is tightened as shown in FIG. By making it larger than the large-diameter dimension of the substitute spline 39, the first cutting blade 81 is allowed to penetrate the spline-forming inner peripheral surface 50 during the slotting process shown in FIG. It can escape to the part 52. Therefore, the protruding portion (chip) formed by cutting with the first cutting blade 81 naturally falls off the intermediate part 1 ′ at the point where the first cutting blade 81 reaches the escape portion 52. On the other hand, the protruding portion formed by cutting with the second cutting blade 82 does not fall off from the intermediate part 1 'after the slotting process, and remains in a state of being connected to the intermediate part 1'. For this reason, after the spline processing, a process for removing the protruding portion is necessary, which may increase the cost.

  In order to prevent the above problems, as shown in FIG. 13, the first region 501 in which the tightening spline 39 is formed and the guide spline 44 are formed in the spline forming inner peripheral surface 50 of the intermediate part 1 ′. It is preferable to form a second relief portion 54 for escaping the second cutting blade 82 at the boundary with the second region 502. The second relief portion 54 can be formed by a groove extending in the circumferential direction, for example, an annular groove. As shown in FIG. 15, the inner diameter of the bottom surface of the second relief portion 54 is larger than the larger diameters of the fastening spline 39 and the guide spline 44.

  By forming the second relief portion 54 in the intermediate part 1 ′ in this way, as shown in FIG. 14, the first cutting blade 81 reaches the first relief portion 52 and the second cutting blade 82 is also first In order to reach the second escape portion 54, both the protruding portion 55 formed by the first cutting blade 81 and the protruding portion 56 formed by the second cutting blade 82 are naturally dropped from the intermediate part 1 ′. be able to. Accordingly, the step of removing the protruding portion can be eliminated, and the manufacturing cost of the hub wheel 1 can be reduced.

  As shown in the enlarged view of FIG. 15, the second relief portion 54 also remains on the inner peripheral surface of the completed hub wheel 1. In this case, a second relief portion 54 having a diameter larger than that of the guide spline 44 is formed between the fastening spline 39 formed on the inner peripheral surface of the hub wheel of the wheel bearing and the guide spline 44. Also in the wheel bearing device formed by coupling the wheel bearing 20 and the constant velocity universal joint 6 as shown in FIG. 16, the second relief portion 54 remains on the inner peripheral surface of the hub wheel 1.

  Hereinafter, for reference, an outline of a hub wheel machining process to which the wheel bearing machining method of the present embodiment is applied is shown in FIGS. First, a base material is manufactured in the forging process shown in FIG. Thereafter, in the primary turning process shown in FIG. 17B, the outer peripheral surface, the inner peripheral surface, the insertion hole and the like (including the first relief portion 52 and the second relief portion 54) of the base material are turned. The intermediate part 1 ′ is manufactured. Subsequently, in the spline processing step shown in FIG. 17 (c), the above-described spline processing is performed on the intermediate part 1 ′ to obtain a spline-formed product 1 ″. This spline processing step is the spline processing method of the present embodiment. In the secondary turning process shown in Fig. 17 (d), the cylindrical outer peripheral surface, the small diameter step, etc. of the spline-formed product 1 "are turned. Thereafter, in the heat treatment step shown in FIG. 17 (e), a heat treatment hardened layer is formed on the root of the wheel mounting flange, the inner raceway surface, the cylindrical outer peripheral surface, and a part of the small diameter step portion. Finally, in the grinding step shown in FIG. 17 (f), the root of the wheel mounting flange, the inner raceway surface, and the small diameter step are ground to complete the hub wheel.

  In the spline processing method for wheel bearings according to the above embodiment, one of the double-row inner raceway surfaces 7 and 8 formed on the inner member including the hub wheel 1 and the inner race, that is, the inner raceway surface on the outboard side. 7 is applied to a vehicle bearing of the type (referred to as the third generation) formed on the outer periphery of the hub wheel 1, but the present invention is not limited to this, and the outer periphery of the hub wheel 1 A pair of inner rings are press-fitted, and an outboard side raceway ring 7 is formed on the outer periphery of one inner ring, and an inboard side raceway surface 8 is formed on the outer periphery of the other inner ring (referred to as first and second generations). It is also applicable to wheel bearings of the type).

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

DESCRIPTION OF SYMBOLS 1 Hub wheel 1 'Intermediate part 2 Inner ring 3 Rolling element 4 Rolling element 5 Outer member 6 Constant velocity universal joint 7 Inner raceway surface 8 Inner raceway surface 12 Small diameter step part 13 Outer raceway surface 14 Outer raceway surface 15 Cage 16 Cage 20 Wheel Bearing 24 Outer Joint Member 30 Stem Part 32 Bolt 37 Male Spline 38 Shaft Hole 39 Tightening Spline 44 Guide Spline 50 Spline Formation Inner Surface 52 First Escape Part 54 Second Escape Part 80 Slotter Tool 81 First Cutting Blade 82 Second cutting blade 83 Holding member m Clearance n Fastening allowance p Clearance

Claims (3)

An outer member having a double row outer raceway surface formed on the inner peripheral surface, an inner member having a double row inner raceway surface facing the outer raceway surface on the outer peripheral surface, and an outer side of the outer member A double row rolling element interposed between the raceway surface and the inner raceway surface of the inner member, and a cage for holding the rolling element, and a spline with a fastening margin on the inner periphery of the inner member In the spline processing method for a wheel bearing in which the guide spline is formed at the inboard side end of the tightening spline,
By means of slotting using a slotter tool having a first cutting blade corresponding to the tightening spline and a second cutting blade corresponding to the guide spline in the intermediate part of the inner member, the spline with the tightening margin and the guide spline A spline machining method for a wheel bearing, characterized in that   2. The wheel bearing according to claim 1, wherein a first relief portion for allowing the first cutting blade to escape is formed on an outboard side of an intermediate part of the inward member in an area where the spigot spline is formed. Spline processing method.   A second relief portion for escaping the second cutting blade at a boundary portion between the first region where the fastening spline is formed and the second region where the guide spline is formed, of the intermediate part of the inner member. The spline processing method of the wheel bearing of Claim 1 or 2 which forms.

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