Manufacturing method for crimped assemblies, manufacturing method for hub unit bearings, manufacturing method for vehicles, manufacturing method for mechanical devices, manufacturing apparatus for crimped assemblies, manufacturing apparatus for hub unit bearings, mechanical devices, and vehicles

Abstract

Formation of the face spline includes a step of pressing the die (39) against the crimped portion (19a) with a first relative motion between the die (39) and the crimped portion (19a) around a reference axis (C), and a step of pressing the die (39) against the crimped portion (19a) with a second relative motion between the die (39) and the crimped portion (19a) around the reference axis (C). During the first relative motion, a partial machining position on the crimped portion (19a) moves in a first circumferential direction. During the second relative motion, a partial machining position on the crimped portion (19a) moves in a second circumferential direction opposite to the first circumferential direction.

Description

[Technical Field]

[0001] The present disclosure relates to a method for manufacturing a crimped assembly, a method for manufacturing a hub unit bearing, a method for manufacturing a vehicle, a method for manufacturing a mechanical device, a vehicle manufacturing apparatus, a mechanical device manufacturing apparatus, a mechanical device, and a vehicle. This application claims priority from Japanese Patent Application No. 2024-094964, filed June 12, 2024, the contents of which are incorporated herein by reference. [Background technology]

[0002] A wheel drive unit is used to support the drive wheels on an independent suspension and to drive the drive wheels to rotate. The wheel drive unit is made up of a hub unit bearing and a constant velocity joint (CVJ) combined by a connecting member.

[0003] The hub unit bearing includes an outer ring, a hub, and a plurality of rolling elements, and supports the drive wheel rotatably relative to the suspension device.

[0004] The outer ring has a double row outer ring raceway on its inner circumferential surface and is supported and fixed to the suspension system.

[0005] The hub has a double-row inner ring raceway on its outer circumferential surface, and a hub-side face spline on its axially inner end face, which is made up of concave and convex portions alternately arranged in the circumferential direction. A wheel is coupled and fixed to the hub.

[0006] The hub includes an inner ring and a hub wheel. The inner ring is fitted without rattle onto a fitting shaft portion provided on the axially inner side of the hub wheel (inside the vehicle width direction when the hub unit bearing is assembled to the vehicle), with its axially outer end face (outside the vehicle width direction when the hub unit bearing is assembled to the vehicle) abutting against a stepped surface provided on the axially middle portion of the hub wheel and facing axially inward. In this state, the axially inner end face of the inner ring is pressed by a crimped portion formed by plastically deforming radially outward a cylindrical portion of the fitting shaft portion that protrudes axially inward beyond the axially inner end face of the inner ring. This connects and fixes the inner ring and the hub wheel and applies a preload to the rolling elements. The hub-side face spline is formed on the axially inner end face of the crimped portion.

[0007] The rolling elements are arranged between double rows of outer ring raceways and double rows of inner ring raceways, with a plurality of rolling elements arranged for each row.

[0008] The constant velocity joint includes a joint outer ring, a joint inner ring, and a plurality of balls, and transmits the rotational torque of the drive shaft to the hub.

[0009] The joint outer ring has, on its axially outer surface, joint side face splines that engage with the hub side face splines, and has outer diameter side engagement grooves that extend in the axial direction at multiple locations circumferentially on its inner surface.

[0010] The joint inner ring has inner diameter side engagement grooves extending in the axial direction at multiple locations on the outer circumferential surface, and is fitted onto the drive shaft.

[0011] The plurality of balls are disposed between the outer diameter side engagement groove and the inner diameter side engagement groove.

[0012] The connecting member is formed of a bolt or the like, and connects the hub and the joint outer ring.

[0013] When the joint inner ring rotates in accordance with the rotation of the drive shaft, the rotation of the joint inner ring is transmitted to the joint outer ring via the balls, and the rotation of the joint outer ring is then transmitted to the hub through the engagement between the joint-side face spline and the hub-side face spline, thereby driving and rotating the drive wheel supported and fixed to the hub.

[0014] JP 2017-013079 A describes a face spline forming method using orbital forging, in which a crimped portion for joining a hub wheel and an inner ring is formed, and then the tooth profile (machined portion) of a punch (pressing die) supported so as to be rotatable about a central axis inclined with respect to a reference axis arranged coaxially with the central axis of the hub wheel is pressed against the axially inner end face of the crimped portion, while the pressing die is rotated in one direction about the reference axis to plastically deform the axially inner end face of the crimped portion, thereby forming a hub-side face spline. [Prior art documents] [Patent documents]

[0015] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-013079 Summary of the Invention [Problem to be solved by the invention]

[0016] In the method described in JP 2017-013079 A, ​​stress concentration occurs at the base of the side surface on the front side in the rotation direction of the pressing die, which tends to increase manufacturing costs.

[0017] An object of the present disclosure is to provide a manufacturing method and manufacturing apparatus that are advantageous in reducing manufacturing costs and / or improving product quality. [Means for solving the problem]

[0018] A method for manufacturing a crimped assembly according to one aspect of the present invention includes the steps of: preparing a first member having a crimped portion, wherein a second member is axially fixed to the first member by the crimped portion; setting a face spline die, wherein a central axis of the die is inclined with respect to a reference axis; and forming a face spline on the crimped portion of the first member using the die. The forming of the face spline includes the steps of: pressing the die against the crimped portion with a first relative motion between the die and the crimped portion, wherein the first relative motion moves a partial machining position on the crimped portion in a first circumferential direction; and pressing the die against the crimped portion with a second relative motion between the die and the crimped portion, wherein the second relative motion moves a partial machining position on the crimped portion in a second circumferential direction opposite to the first circumferential direction.

[0019] In another aspect of the present invention, a method for manufacturing a mechanical device includes manufacturing a crimped assembly using the manufacturing method described above, and assembling the crimped assembly to a device body.

[0020] In another aspect of the present invention, a method for manufacturing a hub unit bearing includes the steps of: setting a stamping die for a face spline, wherein the central axis of the stamping die is disposed at an angle with respect to a reference axis; and forming a face spline using the stamping die on a hub body having rolling elements and an outer ring attached thereto. Forming the face spline includes the steps of: pressing the stamping die against the hub body with a first relative motion between the stamping die and the hub body, wherein the first relative motion moves a partial machining position on the hub body in a first circumferential direction; and pressing the stamping die against the hub body with a second relative motion between the stamping die and the hub body, wherein the second relative motion moves a partial machining position on the hub body in a second circumferential direction opposite to the first circumferential direction.

[0021] In another aspect of the present invention, a method for manufacturing a hub unit bearing includes manufacturing a hub unit bearing using the manufacturing method described above, and assembling the hub unit bearing to a vehicle body.

[0022] In another aspect of the present invention, a manufacturing apparatus for a crimped assembly includes a first mechanism supporting a first member having a crimping portion, wherein a second member is axially fixed to the first member by the crimping portion, a second mechanism supporting a stamping die for a face spline, wherein a central axis of the stamping die is disposed at an angle with respect to a reference axis, a third mechanism pressing the stamping die against the crimped portion with relative motion between the stamping die and the crimped portion, and a control device. The control device has a first mode for performing a first relative motion between the stamping die and the crimped portion, wherein a partial machining position on the crimped portion moves in a first circumferential direction during the first relative motion, and a second mode for performing a second relative motion between the stamping die and the crimped portion, wherein the second relative motion moves a partial machining position on the crimped portion in a second circumferential direction opposite to the first circumferential direction.

[0023] In another aspect of the present invention, a mechanical device includes a crimping assembly manufactured using the above-described manufacturing device, and a device body to which the crimping assembly is attached.

[0024] In another aspect of the present invention, a manufacturing apparatus for hub unit bearings includes a first mechanism that supports a hub body to which rolling elements and an outer ring are attached, a second mechanism that supports a stamping die for a face spline, the central axis of the stamping die being disposed at an angle with respect to a reference axis, a third mechanism that presses the stamping die against the hub body with relative motion between the stamping die and the hub body, and a control device. The control device has a first mode in which a first relative motion is performed between the stamping die and the hub body, and in which a partial machining position on the hub body moves in a first circumferential direction during the first relative motion, and a second mode in which a second relative motion is performed between the stamping die and the hub body, and in which in the second relative motion, a partial machining position on the hub body moves in a second circumferential direction opposite to the first circumferential direction.

[0025] In another aspect of the present invention, a vehicle includes a hub unit bearing manufactured using the above-described manufacturing apparatus, and a vehicle body to which the hub unit bearing is assembled. [Effects of the Invention]

[0026] The aspects of the present invention are advantageous in reducing manufacturing costs and / or improving product quality. [Brief explanation of the drawings]

[0027] [Figure 1] FIG. 1 is a cross-sectional view showing an example of a wheel drive unit equipped with a hub unit bearing. [Figure 2] FIG. 2 is a cross-sectional view showing the state before and after forming the caulking portion in the manufacturing process of the hub unit bearing. [Figure 3] FIG. 3 is a cross-sectional view that schematically shows the face spline forming device, illustrating the state at the start of the face spline forming process. [Figure 4] FIG. 4 is a view corresponding to the upper part of FIG. 3, showing the state at the end of the face spline forming process. [Figure 5] FIG. 5 is a cross-sectional view showing a part of the face spline forming device. [Figure 6] FIG. 6 is a block diagram showing the process steps of forming a face spline. [Figure 7] FIG. 7 is a schematic view corresponding to the cross section taken along line XX in FIG. 4, showing how the hub-side face spline is formed. [Figure 8] FIG. 8 is a schematic diagram showing the state in which a hub-side face spline is formed by a conventional method. [Figure 9] FIG. 9 is a schematic diagram showing a vehicle equipped with a hub unit bearing. [Figure 10] FIG. 10 is a partial schematic diagram showing a vehicle equipped with a hub unit bearing. DETAILED DESCRIPTION OF THE INVENTION

[0028] The first embodiment will be described with reference to FIGS.

[0029] The manufacturing method and manufacturing apparatus of one aspect of the present disclosure are widely applicable to the manufacture of vehicles, mechanical devices, or components thereof, including parts having face splines.

[0030] In one embodiment, the manufacturing method and manufacturing apparatus according to one aspect of the present disclosure are applied to the manufacture of a hub unit bearing that constitutes a vehicle.

[0031] [Wheel drive unit structure] 1 shows a wheel drive unit 1. The wheel drive unit 1 includes a hub unit bearing (caulking assembly) 2 and a constant velocity joint 3.

[0032] In the following description, unless otherwise specified, the axial, radial, and circumferential directions of the wheel drive unit 1 refer to the axial, radial, and circumferential directions of the hub 5 of the hub unit bearing 2. The axial, radial, and circumferential directions of the hub 5 coincide with the axial, radial, and circumferential directions of the outer ring 4 of the hub unit bearing 2 and also coincide with the axial, radial, and circumferential directions of the constant velocity joint 3. Additionally, the outer axial direction refers to the outer side in the width direction of the vehicle body when the wheel drive unit 1 is assembled to the vehicle (left side in Figure 1), and the inner axial direction refers to the inner side in the width direction of the vehicle body when the wheel drive unit 1 is assembled to the vehicle (right side in Figure 1).

[0033] <Hub unit bearing structure> The hub unit bearing 2 includes an outer ring 4, a hub 5, and a plurality of rolling elements 6a, 6b.

[0034] The outer ring 4 has a hollow shape and has a plurality of outer ring raceways 7a, 7b on its inner circumferential surface.

[0035] In one example, the plurality of outer ring raceways 7a, 7b are configured as double-row (two-row) outer ring raceways 7a, 7b.

[0036] Each of the outer ring raceways 7a, 7b has a generatrix shape that corresponds to the shape of the multiple rolling elements 6a, 6b. When the multiple rolling elements 6a, 6b are balls, each of the outer ring raceways 7a, 7b has an arc-shaped generatrix shape. When the multiple rolling elements 6a, 6b are tapered rollers, each of the outer ring raceways 7a, 7b has a linear generatrix shape that is inclined with respect to the central axis of the outer ring 4.

[0037] 1, the plurality of rolling elements 6a, 6b are made up of balls in the hub unit bearing 2. Therefore, each of the outer ring raceways 7a, 7b has an arc-shaped generatrix shape.

[0038] The outer ring 4 has a stationary flange 8 that protrudes radially outward at an axially intermediate portion. The stationary flange 8 has flange-side support holes 9 that penetrate in the axial direction at multiple locations circumferentially at the radially intermediate portion.

[0039] The outer ring 4 is supported and fixed to the knuckle by inserting a support bolt (not shown) into one of the flange side support holes 9 and the knuckle side support hole provided in the knuckle of the suspension device and screwing it into the other support hole.

[0040] The hub 5 is disposed radially inside the outer ring 4 and coaxially with the outer ring 4. The hub 5 has a plurality of inner ring raceways 10a, 10b on its outer peripheral surface.

[0041] In the example of FIG. 1, the plurality of inner ring raceways 10a, 10b are configured as double-row (two-row) inner ring raceways 10a, 10b.

[0042] Each of the inner ring raceways 10a, 10b has a generatrix shape that corresponds to the shape of the multiple rolling elements 6a, 6b. When the multiple rolling elements 6a, 6b are balls, each of the inner ring raceways 10a, 10b has an arc-shaped generatrix shape. When the multiple rolling elements 6a, 6b are tapered rollers, each of the inner ring raceways 10a, 10b has a linear generatrix shape that is inclined with respect to the central axis of the hub 5.

[0043] 1, the plurality of rolling elements 6a, 6b are made up of balls in the hub unit bearing 2. Therefore, each of the inner ring raceways 10a, 10b has an arc-shaped generatrix shape.

[0044] The hub 5 further has a center hole 11 and a hub-side face spline 12 .

[0045] The central hole 11 is provided so as to penetrate the center of the hub 5 in the axial direction.

[0046] The hub-side face spline 12 is provided on the axially inner end surface of the hub 5, and is configured by alternately arranging recesses and protrusions in the circumferential direction. Specifically, the hub-side face spline 12 is provided on the axially inner end surface of a crimped portion 19 provided at the axially inner end of the hub ring 17. The hub-side face spline 12 is also configured by arranging a plurality of protrusions (teeth) that protrude axially inward at equal intervals in the circumferential direction. For example, the respective protrusions (teeth) that make up the hub-side face spline 12 are arranged radially. The cross-sectional shape (tooth flank shape) of the protrusions (teeth) is set to an appropriate profile, such as a linear profile or an involute profile. The protrusions (teeth) are provided to extend at least in the radial direction. Between one protrusion (tooth) and another protrusion (tooth), a recess (groove) extending at least in the radial direction is provided.

[0047] In the example of Figure 1, the hub 5 has a rotating flange 13 that protrudes radially outward at a portion that protrudes axially outward beyond the outer ring 4, and the hub 5 also has a cylindrical pilot portion 14 at its axially outer end.

[0048] For example, the rotary flange 13 has mounting holes 15 penetrating in the axial direction at a plurality of circumferential positions in the radially middle portion thereof. Each of the mounting holes 15 is configured as a press-fit hole or a screw hole.

[0049] When each mounting hole 15 is configured as a press-fit hole, a stud is press-fit into each mounting hole 15 from the axially inner side. The pilot portion 14 is inserted into a central hole provided in the center of each braking rotating body such as a brake disc and the wheel of a vehicle wheel. Studs are also inserted into through-holes provided at multiple locations circumferentially in the radially middle portion of each. Hub nuts are threaded onto the tips of the studs to connect and fix them to the rotating flange 13.

[0050] When each of the mounting holes 15 is configured as a threaded hole, the pilot portion 14 is inserted into a central hole provided at the center of each of the braking rotating body such as a brake disc and the wheel of the vehicle wheel. Hub bolts are inserted into through holes provided at multiple locations circumferentially in the radially middle portion of each of the braking rotating body and the wheel, and are screwed into the mounting holes 15 from the outside in the axial direction, thereby connecting and fixing to the rotating flange 13.

[0051] The hub 5 includes an inner ring 16 and a hub ring 17 .

[0052] The inner ring 16 is cylindrical and made of a hard metal such as bearing steel. In other examples, the inner ring 16 is made of other materials. The inner ring 16 has, on its outer peripheral surface, at least the axially innermost inner ring raceway 10b of the multiple inner ring raceways 10a, 10b. In the example of FIG. 1, the inner ring 16 has, in an axially intermediate portion of its outer peripheral surface, the axially innermost inner ring raceway 10b of the double-row inner ring raceways 10a, 10b.

[0053] In one example, the hub ring 17 is made of a hard metal such as medium carbon steel. In another example, the hub ring 17 is made of another material. The hub ring 17 has, on its outer circumferential surface, at least the axially outermost inner ring raceway 10a of the multiple inner ring raceways 10a, 10b, a fitting shaft portion 18 onto which the inner ring 16 is fitted, and a crimping portion 19 provided on the axially inner end portion and pressing against the axially inner end face of the inner ring 16.

[0054] In the example of FIG. 1, the hub ring 17 has, at the axially middle portion of its outer peripheral surface, the inner ring raceway 10a on the axially outer side of the double row inner ring raceways 10a, 10b.

[0055] The fitting shaft portion 18 is provided at a portion located axially more inward than the axially outer inner ring raceway 10a, and has a cylindrical outer peripheral surface whose outer diameter does not change substantially in the axial direction. A portion of the outer peripheral surface of the hub ring 17 adjacent to the axially inner side of the axially outer inner ring raceway 10a is connected to the outer peripheral surface of the fitting shaft portion 18 by a stepped surface 20 facing axially inward.

[0056] The crimped portion 19 extends radially outward from the axially inner end of the fitting shaft portion 18. The hub-side face spline 12 is provided on the axially inner end surface of the crimped portion 19.

[0057] 1, the hub ring 17 has a rotation flange 13 at a portion located axially outward of the axially outer inner ring raceway 10a. The hub ring 17 also has a pilot portion 14 at its axially outer end.

[0058] The inner ring 16 is fitted onto the fitting shaft portion 18 of the hub ring 17, and is sandwiched from both axial sides between a stepped surface 20 and a crimped portion 19 of the hub ring 17. The inner ring 16 and the hub ring 17 are joined to form the hub 5, and a preload is applied to the rolling elements 6a, 6b.

[0059] The rolling elements 6a, 6b are arranged in rows between the outer ring raceways 7a, 7b and the inner ring raceways 10a, 10b so as to be rollable, and are preloaded.

[0060] In one example, each of the rolling elements 6a, 6b is made of a hard metal such as bearing steel or ceramics, while in another example, the rolling elements 6a, 6b are made of other materials.

[0061] For example, each of the rolling elements 6a and 6b is made up of a ball or a tapered roller. In the example of Fig. 1, each of the rolling elements 6a and 6b is made up of a ball.

[0062] The rolling elements 6a and 6b are arranged at equal intervals in the circumferential direction using cages 21a and 21b each having an annular shape.

[0063] In one example, the hub unit bearing 2 has an equal diameter PCD type design, where the pitch diameter of the rolling elements 6 a in the axially outer row is equal to the pitch diameter of the rolling elements 6 b in the axially inner row. In another example, the hub unit bearing 2 can have a different diameter PCD type design, where the pitch diameter of the rolling elements in the axially outer row is larger or smaller than the pitch diameter of the rolling elements in the axially inner row.

[0064] <Constant velocity joint structure> The constant velocity joint 3 includes a joint outer ring 22, a joint inner ring 23, and a plurality of balls 24.

[0065] The joint outer ring 22 has, on its axially outer surface, a joint side face spline 25 that engages with the hub side face spline 12 of the hub 5 .

[0066] The joint outer ring 22 has a mouth portion 26 that is generally bowl-shaped, and a cylindrical portion 27 .

[0067] The mouth portion 26 has a substantially cylindrical peripheral wall portion 28 and a substantially hollow circular side wall portion 29 that extends radially inward from the axially outer end of the peripheral wall portion 28.

[0068] The inner peripheral surface of the peripheral wall portion 28 is configured as a partially spherical concave surface. The peripheral wall portion 28 has outer diameter side engagement grooves 30 extending in the axial direction at multiple locations in the circumferential direction of the inner peripheral surface.

[0069] The side wall portion 29 has, at a radially intermediate portion of the axially outer surface, a joint-side face spline 25 formed by circumferentially arranging recesses and protrusions alternately.

[0070] The cylindrical portion 27 extends axially outward from the radially inner end of the side wall portion 29. The cylindrical portion 27 has a female thread portion 31 on its inner circumferential surface.

[0071] The joint inner ring 23 has a partially convex spherical outer peripheral surface, and has inner diameter side engagement grooves 32 extending in the axial direction at multiple locations around the circumference of the outer peripheral surface. The joint inner ring 23 also has a spline hole 33 that penetrates in the axial direction at its center. A spline shaft portion provided at the tip of a drive shaft (not shown) is spline-engaged with the spline hole 33.

[0072] Each ball 24 is disposed between the outer diameter side engagement groove 30 and the inner diameter side engagement groove 32 so as to be able to roll along the outer diameter side engagement groove 30 and the inner diameter side engagement groove 32, one for each.

[0073] The hub-side face spline 12 and the joint-side face spline 25 are engaged between the hub 5 of the hub unit bearing 2 and the joint outer ring 22 of the constant velocity joint 3. The shank 35 of a bolt 34 inserted into the center hole 11 from the outside in the axial direction is screwed into the female thread portion 31. The hub 5 is clamped from both axial sides between the head 36 of the bolt 34 and the joint outer ring 22, and the hub 5 is connected and fixed to the joint outer ring 22 of the constant velocity joint 3. This constitutes the wheel drive unit 1.

[0074] [Method for manufacturing hub unit bearing] When manufacturing the hub unit bearing (crimped assembly) 2, the outer ring 4 and multiple rolling elements 6a, 6b are arranged around the hub ring 17a before the crimped portion 19a is formed, as shown in Figure 2. The crimped portion 19a is the crimped portion before the hub-side face spline 12 is formed.

[0075] Before the crimped portion 19a is formed, the hub wheel 17a has a cylindrical portion 37 at its axially inner end adjacent to the axially inner side of the fitting shaft portion 18. The cylindrical portion 37 has an outer diameter that is equal to the outer diameter of the fitting shaft portion 18 and does not change in the axial direction. In other words, the outer peripheral surfaces of the fitting shaft portion 18 and the cylindrical portion 37 are formed by a single cylindrical surface.

[0076] The procedure for arranging the outer ring 4 and the plurality of rolling elements 6a, 6b around the hub ring 17a is not particularly limited, and any procedure can be used as long as no contradiction occurs.

[0077] For example, first, multiple rolling elements 6a, 6b are inserted into pockets of two cages 21a, 21b, and the multiple rolling elements 6a, 6b are held in rows by each cage 21a, 21b. Next, the rows of rolling elements 6a, 6b held by the two cages 21a, 21b are held radially inside the outer ring raceways 7a, 7b of the outer ring 4. Next, the hub ring 17a is inserted from the outside in the axial direction, radially inside the combined outer ring 4, multiple rolling elements 6a, 6b, and cages 21a, 21b. After that, the inner ring 16 is fitted onto the mating shaft portion 18 of the hub ring 17a. In other words, the inner ring 16 is inserted between the axially inner row of rolling elements 6b and the mating shaft portion 18. Then, the cylindrical portion 37 of the hub ring 17a is plastically deformed radially outward to form the crimped portion 19a, thereby joining the inner ring 16 to the hub ring 17b before the hub-side face spline 12 is formed. The inner ring (second member) 16 is fixed axially to the hub ring (first member) 17b by the crimped portion 19a.

[0078] The method for forming the crimped portion 19a is not particularly limited. For example, the crimped portion 19a can be formed by a general forging press process in which a forming die is pressed against the entire circumference of the cylindrical portion 37. Alternatively, the crimped portion 19a can be formed by orbital forging in which a forming die, supported so as to be rotatable about a central axis inclined with respect to the central axis O of the hub ring 17a, is pressed against the cylindrical portion 37 while rotating about the central axis O of the hub ring 17a.

[0079] After the crimped portion 19a is formed as described above, the hub-side face spline 12 is formed on the axially inner end surface of the crimped portion 19a.

[0080] In one embodiment, a manufacturing method for a hub unit bearing (crimped assembly) includes the steps of preparing a hub ring (first member, hub body) 17b having a crimped portion 19a, setting a die 39 for a face spline, and forming a face spline on the crimped portion 19a of the hub ring 17b using the die 39. The central axis (rotation axis) α of the die 39 is disposed at an angle with respect to the reference axis C.

[0081] Here, forming the face spline includes a step of pressing the die 39 against the crimped portion 19a with a first relative motion between the die 39 and the crimped portion 19a, and a step of pressing the die 39 against the crimped portion 19a with a second relative motion between the die 39 and the crimped portion 19a. In the first relative motion, a partial machining position on the crimped portion 19a moves in a first circumferential direction around the reference axis C. In the first relative motion, a contact position (contact portion) of the die 39 with the crimped portion 19a changes in a first direction around the central axis α. In the first relative motion, the positions of the teeth of the die 39 that sequentially engage with the crimped portion 19a shift in the first circumferential direction. In the second relative motion, the partial machining position on the crimped portion 19a moves in a second circumferential direction, opposite to the first circumferential direction, around the reference axis C. During the second relative motion, the contact position (contact portion) of the pressing die 39 with the crimping portion 19a changes in a second direction around the central axis α. During the second relative motion, the positions of the teeth of the pressing die 39 that sequentially engage with the crimping portion 19a shift in a second circumferential direction. In one example, the first relative motion causes the pressing die 39 to rotate in a first direction around the central axis α. During the second relative motion, the pressing die 39 rotates in a second direction opposite to the first direction around the central axis α.

[0082] In one example, in the first relative motion, the processing portion 42 (processing position) of the press die 39 moves in a first circumferential direction around the reference axis C relative to the crimping portion 19a. In the second relative motion, the processing portion 42 (processing position) of the press die 39 moves in a second circumferential direction opposite to the first circumferential direction around the reference axis C relative to the crimping portion 19a. For example, in the first relative motion, the crimping portion 19a is fixed in the rotational direction about the reference axis C, and the processing portion 42 (processing position) of the press die 39 moves in the first circumferential direction about the reference axis C. In the second relative motion, the crimping portion 19a is fixed in the rotational direction about the reference axis C, and the processing portion 42 (processing position) of the press die 39 moves in a second circumferential direction about the reference axis C. Alternatively, in the first relative motion, the processing portion 42 (processing position) of the press die 39 is fixed in the circumferential direction about the reference axis C, and the crimping portion 19a rotates in the second circumferential direction about the reference axis C. In the second relative motion, the processing portion 42 (processing position) of the pressing die 39 is fixed in the circumferential direction around the reference axis C, and the crimping portion 19a is rotated in the first circumferential direction around the reference axis C. Alternatively, in each of the first relative motion and the second relative motion, the crimping portion 19a and the processing portion 42 (processing position) of the pressing die 39 are rotated or moved in opposite directions around the reference axis C, and the relative speeds in the first relative motion and the second relative motion are appropriately set. Alternatively, in each of the first relative motion and the second relative motion, the crimping portion 19a and the processing portion 42 of the pressing die 39 are rotated or moved in the same direction around the reference axis C, and the relative speeds in the first relative motion and the second relative motion are appropriately set.

[0083] In one example, forming the face spline further includes a step of pressing the die 39 against the crimped portion 19a with a third relative motion between the die 39 and the crimped portion 19a. In the third relative motion, a partial machining position on the crimped portion 19a moves in a first circumferential direction or a second circumferential direction around the reference axis C. In the third relative motion, a contact position (contact portion) of the die 39 with the crimped portion 19a changes in a third direction around the central axis α. In the third relative motion, positions of teeth of the die 39 that sequentially engage with the crimped portion 19a shift in the third circumferential direction. The third direction is opposite to the first direction or the second direction. The third circumferential direction is opposite to the first circumferential direction or the second circumferential direction. In one example, in association with the third relative motion, the die 39 rotates in a third direction around the central axis α. As with the first relative motion and the second relative motion, various forms can be applied to the motion of the press die 39 (processing portion 42) and the crimping portion 19a in the third relative motion.

[0084] In one example, the relative speed (set relative speed, average relative speed, maximum relative speed, actual relative speed) between the press die 39 and the crimping portion 19a in the third relative motion is different from at least one of the relative speed in the first relative motion and the relative speed in the second relative motion. For example, the relative speed in the first relative motion and the relative speed in the second relative motion are substantially the same as each other, and the relative speed in the third relative motion (second relative speed) is smaller or larger than the first relative speed. Alternatively, the relative speed in the first relative motion and the relative speed in the second relative motion are different from each other, and the relative speed in the second relative motion and the relative speed in the third relative motion are different from each other. In addition to this, various other forms of the relationship between the relative speeds can be applied.

[0085] In one example, the axial movement amount of the pressing die 39 relative to the crimping portion 19a in the third relative motion (axial movement amount along the reference axis C) is different from at least one of the axial movement amount in the first relative motion and the axial movement amount in the second relative motion. For example, the axial movement amount in the first relative motion and the axial movement amount in the second relative motion are substantially the same as each other, and the axial movement amount in the third relative motion (second axial movement amount) is smaller or larger than the first axial movement amount. Alternatively, the axial movement amount in the second relative motion is smaller than the axial movement amount in the first relative motion, and the axial movement amount in the third relative motion is even smaller than the axial movement amount in the second relative motion. In addition to the above, various other forms of the relationship between the axial movements are applicable.

[0086] In one example, before the pressing with the third relative motion, the pressing with the first relative motion and the pressing with the second relative motion are performed once. For example, the pressing with the first relative motion is performed once, the pressing with the second relative motion is performed once, and then the pressing with the third relative motion is performed once. In another example, before the pressing with the third relative motion, the pressing with the first relative motion and the pressing with the second relative motion are performed multiple times. For example, before the pressing with the third relative motion, the pressing with the first relative motion and the pressing with the second relative motion are performed alternately multiple times. The number of times of the first relative motion and the number of times of the second relative motion may be the same or different.

[0087] In one example, the first relative motion and the second relative motion are performed in a rough forming stage in forming the face spline, and the third relative motion is performed in a finish forming stage in forming the face spline.

[0088] In one example, a face spline molding process is performed to form the hub-side face spline 12. The pressing die 39 has a processing portion 42 configured by alternately arranging recessed portions 54 and protruding portions (teeth) 55 in the circumferential direction centered on its rotation axis α, and is supported so as to be rotatable about the central axis (rotation axis) α. In the face spline process, with the pressing die 39 inclined at a predetermined angle θ with respect to the central axis O of the workpiece (workpiece, hub ring 17b), a portion of the processing portion 42 is pressed against an annular processing portion (crimping portion 19a) provided coaxially on the workpiece (hub ring 17b), and the pressing die 39 is rotated about the central axis O of the workpiece (hub ring 17b), thereby forming a face spline (hub-side face spline 12) in the processing portion (crimping portion 19a). The relative rotation direction of the pressing die 39 around the central axis O of the workpiece (hub wheel 17b) is reversed at least once during the face spline forming process (the mode of relative movement is switched).

[0089] <Structure of the face spline forming device> The face spline forming process can be performed using a face spline forming apparatus (a manufacturing apparatus for a crimped assembly, or a part of a manufacturing apparatus for a crimped assembly) 38 as shown in Figures 3 to 5 and 7. The face spline forming apparatus 38 includes a support mechanism (first mechanism) 61 including a support stand 50, a press die 39 for the face spline, a press die support mechanism (second mechanism) 40, a spindle drive mechanism (third mechanism) 41, and a control device 53.

[0090] The support mechanism 61 supports the hub wheel 37b (first member) having the crimped portion 19a. The main shaft drive mechanism 41 presses the die 39 against the crimped portion 19a by causing relative motion between the die 39 and the crimped portion 19a. The control device 53 has a first mode in which a first relative motion is performed between the die 39 and the crimped portion 19a, and a second mode in which a second relative motion is performed between the die 39 and the crimped portion 19a. In one example, in the first mode, the die 39 rotates in a first direction around the central axis α by causing the first relative motion. In the second mode, the die 39 rotates in a second direction opposite to the first direction around the central axis α by causing the second relative motion.

[0091] The die 39 is pressed against the crimped portion 19a of the hub wheel 17b to plastically deform the axially inner end surface of the crimped portion 19a, thereby forming the hub-side face spline (face spline) 12. The die 39 is supported by a die support mechanism 40 so as to be rotatable about the rotation axis α, which is the central axis of the die 39, with the rotation axis α inclined at a predetermined angle θ with respect to the reference axis C. In one example, the predetermined angle θ can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 degrees, or more. For example, the predetermined angle θ can be 3 degrees or more and 5 degrees or less. For example, the inclination angle θ can be approximately 5 degrees. The above values ​​are merely examples and are not limiting.

[0092] The reference axis C is an axis that is arranged coaxially with the hub ring 17b, which is the workpiece. The hub unit bearing 2, which includes the hub ring 17b, which is the workpiece, is set in the face spline forming device 38 so that its central axis O coincides with the reference axis. The extension direction of the reference axis C is not particularly limited and can be any direction, such as the vertical direction (up and down direction) or the horizontal direction. In one example, the reference axis C extends in the vertical direction. More specifically, the hub unit bearing 2, which includes the hub ring 17b, which is the workpiece, is set in the face spline forming device 38 with the axially inner side facing upward and the axially outer side facing downward.

[0093] The pressing die 39 has a processing portion 42 at its tip (the lower end portion in Figures 3 to 5) that is configured by alternately arranging recesses 54 and protrusions 55 in the circumferential direction centered on the rotation axis α.

[0094] In one example, as shown in Figure 5, the die 39 includes a shaft member 43 and a die body 44. The shaft member 43 has a stepped cylindrical shape. The die body 44 is supported and fixed to the tip end (the lower end in Figure 5) of the shaft member 43. The processing section 42 is provided on the end surface of the die body 44 on the tip side.

[0095] The die support mechanism 40 supports the die 39 so that it can rotate about the rotation axis α with the rotation axis α inclined at a predetermined angle θ with respect to the reference axis C. For example, the die support mechanism 40 includes a die support block 45 and an inner bearing device 46.

[0096] The pressing die support block 45 is disposed coaxially with the reference axis C and is supported so as to be rotatable about the reference axis C. For example, the pressing die support block 45 has a cylindrical shape and is rotatably supported by an outer bearing device 48 with respect to a frame 47 that does not rotate or move during operation of the face spline forming device 38.

[0097] The die support block 45 has a die support recess 49 formed in a direction inclined with respect to the reference axis C. The die support recess 49 has a cylindrical inner peripheral surface whose inner diameter does not change in the axial direction of the die support recess 49. The inclination angle of the central axis of the die support recess 49 with respect to the reference axis C is the same magnitude (θ) as the inclination angle of the rotation axis α of the die 39 with respect to the reference axis C.

[0098] The die support recess 49 opens onto at least one of the axially opposite side surfaces of the die support block 45, the side surface closer to the hub unit bearing 2 including the hub wheel (workpiece) 17b set in the face spline forming device 38. In one example, the die support recess 49 is configured as a bottomed hole that opens only onto the lower side surface of the die support block 45. In another example, the die support recess can be configured as a through hole that opens onto both axially opposite side surfaces of the die support block.

[0099] The inner bearing device 46 is disposed between the die 39 and the die support recess 49. This allows the die 39 to rotate about the rotation axis α relative to the die support block 45. In one example, the inner bearing device 46 is disposed between the base end of the die 39 (the upper end in FIG. 5 ) and the die support recess 49.

[0100] The main shaft driving mechanism 41 is capable of driving the press die support mechanism 40 to rotate around the reference axis C, and of reversing the direction of rotation (switching the mode of relative movement).

[0101] Specifically, the spindle drive mechanism 41 uses an electric motor as a drive source to rotate the press die support block 45 around the reference axis C. The electric motor rotates the press die support block 45 directly or via a reducer. The electric motor is configured to be rotatable in both forward and reverse directions, and its rotation direction can be switched based on a command from the control device 53.

[0102] The control device 53 controls the direction of rotation to be reversed at least once during the process (switching the relative motion mode once) in the process of forming a face spline in the processed portion of the workpiece by the processing part 42 of the press die 39 while the main shaft drive mechanism 41 drives the press die support mechanism 40 to rotate around the reference axis C.

[0103] The face spline forming device 38 is equipped with a support stand 50 (support mechanism 61) that supports the hub unit bearing 2 including the hub wheel 17b, which is the workpiece, to enable relative movement (relative motion) in the axial direction of the reference axis C with respect to the pressing die 39.

[0104] The support base 50 supports the hub unit bearing 2 without any radial rattle, with its central axis O aligned with the reference axis C, with the axially inner side facing upward and the axially outer side facing downward. In this example, the support base 50 has a recess 51 that opens to the upper surface. The hub unit bearing 2 is supported by the support base 50 by fitting the pilot portion 14 of the hub 5 into the recess 51 without any radial rattle.

[0105] In one example, the support base 50 is supported relative to the frame 47 so as to be movable in the vertical direction, which is the axial direction of the reference axis C, and is movable in the vertical direction by a hydraulic mechanism. In another example, the support base that supports the hub unit bearing is supported so as not to be able to move in the axial direction of the reference axis, and the pressing die can be configured to be moved in the axial direction of the reference axis by a hydraulic mechanism.

[0106] The face spline forming device 38 of this example further includes an outer ring drive mechanism 52 that drives the outer ring 4 of the hub unit bearing 2 to rotate relative to the hub ring 17b and the inner ring 16.

[0107] The outer wheel drive mechanism 52 uses an electric motor as a drive source to rotate the outer wheel 4. The structure of the outer wheel drive mechanism 52 is not particularly limited. For example, the outer wheel drive mechanism 52 can be configured to rotate a jig supported and fixed to the stationary flange 8 using the electric motor via a reducer.

[0108] <Face spline molding method> A specific method for forming the hub-side face spline 12 on the crimped portion 19a using the face spline forming apparatus 38 of this example will be described with reference to FIG. 6 in addition to FIGS. 3 to 5 and 7.

[0109] First, the hub wheel 17b is positioned so that the central axis O of the hub wheel 17b is coaxial with the reference axis C. In this example, the pilot portion 14 of the hub 5 is fitted into the recess 51 without any radial play, thereby supporting the hub unit bearing 2 with respect to the support base 50 so that its central axis O coincides with the reference axis C, with the axially inner side facing upward and the axially outer side facing downward, without any radial play.

[0110] Next, the face spline forming process is performed in which the pressing die 39 is rotated around the reference axis C while pressing a part of the processed portion 42 (a part in the circumferential direction centered on the rotation axis α) against the crimped portion 19a with the rotation axis α inclined at a predetermined angle θ relative to the reference axis C, thereby forming the hub-side face spline 12 in the crimped portion 19a.

[0111] Specifically, by raising the support base 50, a circumferential portion of the processed portion 42 of the press die 39 is brought into contact with a circumferential portion of the crimped portion 19a of the hub wheel 17b, as shown in Figure 3. Then, an upward load is applied to the hub unit bearing 2 by the support base 50, and the circumferential portion of the processed portion 42 is pressed against a circumferential portion of the crimped portion 19a, while the main shaft drive mechanism 41 drives the press die support block 45 of the press die support mechanism 40 to rotate about the reference axis C, thereby rotating the press die 39.

[0112] The die 39 rotates (spins) about the rotation axis α based on frictional force and / or mechanical engagement force acting on the contact portion between the processed portion 42 and the axially inner end of the crimped portion 19a. Alternatively, at least a portion of the die 39 on the rotation axis α moves circumferentially around the reference axis C relative to the crimped portion. The positions of the teeth of the die 39 that sequentially engage with the crimped portion 19a shift circumferentially around the rotation axis α. Therefore, the rotation axis α of the die 39 whirls around the reference axis C like a locus of a central axis due to precession. This applies a load to a portion of the crimped portion 19a in the circumferential direction, continuously changing the portion to which the load is applied in the circumferential direction and gradually plastically deforming the crimped portion 19a, thereby forming the hub-side face spline 12 in the crimped portion 19a. In other words, the crimped portion 19 having the hub-side face spline 12 formed thereon is obtained.

[0113] In one example, in such a face spline forming process, the rotation direction of the press die 39 about the central axis O of the workpiece (hub wheel 17b), i.e., the rotation direction of the press die 39 about the reference axis C, is reversed at least once during the process. Alternatively, the circumferential movement direction (rotation direction) of at least a portion of the press die 39 on the rotation axis α is reversed at least once during the process. The reversal switches the mode of relative motion.

[0114] In one example, the rotation direction of the die 39 around the reference axis C is reversed (mode switching) by reversing the rotation direction of the die support block 45 using the spindle drive mechanism 41 based on a control command from the control device 53.

[0115] In one example, as shown in FIG. 6, the face spline forming process is divided into a rough forming process and a finish forming process that follows the rough forming process.

[0116] In the rough forming process, the press die 39 is rotated about the reference axis C while being moved relative to the workpiece, i.e., the hub wheel 17b, in the axial direction of the reference axis C. The rough shape of the hub-side face spline 12 is formed at the axially inner end of the crimped portion 19a. For example, in the rough forming process, the amount of axial movement of the press die 39 relative to the workpiece, i.e., the hub wheel 17b, per rotation of the press die 39 about the reference axis C (the amount of movement in the axial direction along the reference axis C) is kept constant.

[0117] In one example, in the finish forming process, the die 39 is not moved axially relative to the hub wheel 17b, which is the workpiece. In another example, the amount of movement (axial movement) of the die 39 along the reference axis C in the finish forming process is less than that in the rough forming process. For example, the amount of axial movement of the die 39 in the finish forming process is 1 / 5, 1 / 6, 1 / 7, 1 / 8, 1 / 9, 1 / 10, 1 / 20, 1 / 30, 1 / 40, 1 / 50, or less of the amount of axial movement in the rough forming process. The above numerical values ​​are merely examples and are not limiting. The shape of the hub-side face spline 12 formed at the axially inner end of the crimped portion 19 is adjusted by rotating the die 39 around the reference axis C.

[0118] In one example, the rough forming and finish forming steps are performed using the same face spline forming device 38.

[0119] In one example, the rotation direction of the press die 39 around the reference axis C is reversed at least once during the rough forming process but not during the finish forming process. In another example, the rotation direction is reversed (mode changed) multiple times during the rough forming process and reversed (mode changed) once or multiple times during the finish forming process. In one example, in a first mode (first relative motion) of the rough forming process, at least a portion of the press die 39 on the rotation axis α moves in a first circumferential direction around the reference axis C relative to the crimped portion 19a. Furthermore, the positions of the teeth of the press die 39 that sequentially engage with the crimped portion 19a shift in the first circumferential direction, and the partial processing position on the crimped portion 19a moves in the first circumferential direction around the reference axis C. In a second mode (second relative motion) of the rough forming process, at least a portion of the press die 39 on the rotation axis α moves in a second circumferential direction around the reference axis C relative to the crimped portion. Furthermore, among the multiple teeth of the pressing die 39, the positions of the teeth that sequentially engage with the crimped portion 19a shift in the second circumferential direction, and the partial machining position on the crimped portion 19a moves in the second circumferential direction around the reference axis C. In the third mode (third relative motion) of the finish forming process, at least a portion of the pressing die 39 on the rotation axis α moves in the first circumferential direction or the second circumferential direction around the reference axis C relative to the crimped portion. Furthermore, among the multiple teeth of the pressing die 39, the positions of the teeth that sequentially engage with the crimped portion 19a shift in the first circumferential direction or the second circumferential direction, and the partial machining position on the crimped portion 19a moves in the first circumferential direction or the second circumferential direction around the reference axis C.

[0120] In one example, the rotation direction of the pressing die 39 around the reference axis C is reversed only once during the rough forming process. Specifically, during the rough forming process, the direction of rotation of the pressing die support block 45 by the spindle drive mechanism 41 is initially set to the forward rotation direction (rough forming 1), and then switched to the reverse rotation direction (rough forming 2) midway through.

[0121] 3 to 5, when the die 39 is viewed from above, if the clockwise rotation direction is set as the forward rotation direction, the counterclockwise rotation direction becomes the reverse rotation direction, and if the counterclockwise rotation direction is set as the forward rotation direction, the clockwise rotation direction becomes the reverse rotation direction.

[0122] In another example, the rotation direction of the pressing die 39 around the reference axis C can be reversed two or more times during the rough forming step. In this case, for example, the rotation direction can be reversed every time the pressing die 39 rotates around the reference axis C, that is, rotation in the forward direction (rough forming 1) and rotation in the reverse direction (rough forming 2) can be alternately repeated every other rotation.

[0123] In the rough forming step, the number of times that the pressing die 39 is rotated in the forward direction about the reference axis C may be the same as or different from the number of times that the pressing die 39 is rotated in the reverse direction about the reference axis C. In one example, in the rough forming step, the number of times that the pressing die 39 is rotated in the forward direction is the same as the number of times that the pressing die 39 is rotated in the reverse direction.

[0124] In one example, the rotation speed (number of rotations) of the press die 39 when rotating in the forward direction can be the same as the rotation speed when rotating in the reverse direction. Therefore, in this example, the time for rotating the press die 39 in the forward direction is the same as the time for rotating the press die 39 in the reverse direction. More specifically, in this example, the press die 39 is rotated in the forward direction for a predetermined time while moving relative to the hub wheel 17b in the axial direction of the reference axis C at a predetermined speed, and then the press die 39 is rotated in the reverse direction for the predetermined time while moving relative to the hub wheel 17b in the axial direction of the reference axis C at the same predetermined speed.

[0125] In the rough forming step, the rotation speed (relative speed) of the pressing die 39 about the reference axis C can be set arbitrarily depending on the material of the workpiece and / or the required specifications of the face spline. For example, the rotation speed (relative speed) in the rough forming step is set to 50 min -1Over 500min -1 It can be less than 100 min, preferably -1 Over 300min -1 The above numerical values ​​are merely examples and are not limiting.

[0126] In one example, in the finish forming process, the rotation direction of the pressing die 39 around the reference axis C is kept constant without being reversed midway. In the finish forming process, the rotation direction of the pressing die 39 around the reference axis C can be either a forward rotation direction or a reverse rotation direction. In one example, the rotation direction is set to the opposite direction to the final rotation direction in the rough forming process. In other words, since the final rotation direction in the rough forming process is a reverse rotation direction, the rotation direction in the finish forming process is set to the forward rotation direction.

[0127] In the finish forming process, the rotation speed (relative speed) of the pressing die 39 about the reference axis C can be set arbitrarily depending on the material of the workpiece and / or the required specifications of the face spline. For example, the rotation speed (relative speed) in the rough forming process is set to 100 min -1 Over 400min -1 It can be less than 150 min, preferably -1 More than 250min -1 The above numerical values ​​are merely examples and are not limiting.

[0128] The timing to end the rough forming process and the timing to end the finish forming process can be determined by any means. For example, the timing to end these processes can be determined based on the relationship between the amount of plastic deformation of the crimped portion 19a, the elapsed time from the start of processing, the current value of the electric motor constituting the spindle drive mechanism 41, and other factors, which have been determined through prior experiments. In one example, the timing to switch from the rough forming process to the finish forming process is determined based on the detection results of a sensor (not shown). For example, the timing to switch from the rough forming process to the finish forming process can be determined based on the detection results of the load during processing (e.g., the detection results of the load change) detected by the sensor (not shown). Generally, the load change is relatively large in the rough forming process and relatively small in the finish forming process. In another example, the timing to switch from the rough forming process to the finish forming process can be determined based on the detection results of the axial movement amount (axial movement amount along the reference axis C) relative to the crimped portion 19a. Generally, the amount of axial movement is relatively large in the rough forming process, and relatively small in the finish forming process.

[0129] In one example, the face spline can be formed by rotating the outer ring 4 relative to the hub ring 17b (the crimped portion 19a) while the die 39 is pressed against the hub ring 17b (the crimped portion 19a). For example, during the face spline forming process, the outer ring 4 is driven to rotate relative to the hub ring 17b and the inner ring 16 by the outer ring drive mechanism 52 throughout the process of forming the hub-side face spline 12 by plastically deforming the crimped portion 19a. This prevents the rolling elements 6a, 6b from rotating and revolving about their axes and plastically deforming the crimped portion 19a, thereby preventing indentations from being formed in the outer ring raceways 7a, 7b and the inner ring raceways 10a, 10b.

[0130] Here, in the face spline molding method, reversing the rotation direction of the pressing die 39 about the reference axis C at least once during the face spline molding process is advantageous in ensuring the life of the pressing die 39.

[0131] That is, in the face spline molding process, when the hub-side face spline 12 is formed, stress concentration occurs at the base portion of the side surface on the front side in the rotation direction of the stamping die 39 centered on the reference axis C, among both circumferential side surfaces of the convex portion 55 that constitutes the processing portion 42.

[0132] Figure 8 shows how a face spline is formed using a conventional face spline molding method. As shown in Figure 8, the processing portion 101 of a conventional stamping die 100 is configured by alternately arranging recesses 102 and protrusions (teeth) 103 in the circumferential direction around the central axis (rotation axis) of the stamping die 100. When a hub-side face spline 105 is formed on the axially inner end surface of the crimped portion 104, a reaction force is received from the crimped portion 104, resulting in a stress concentration at a base portion P of the side surface on the front side in the direction of rotation of the stamping die 100, among both circumferential side surfaces of the protrusion 103 that constitutes the processing portion 101 of the stamping die 100.

[0133] Furthermore, when forming the face spline 105, the stamping die 100 is driven to rotate in only one direction around the reference axis, so stress concentration occurs in the root portion P every time the stamping die 100 rotates once around the reference axis. In other words, the number of times stress concentration occurs in the root portion P increases until the face spline 105 is completed, which shortens the life of the stamping die 100 and tends to increase costs.

[0134] In this regard, FIG. 7 shows the formation of a face spline using the method of the present invention. In FIG. 7, stress concentration is alleviated by reversing the rotation direction of the die 39 about the reference axis C (the direction of movement of the machining position of the die 39 or the direction of shifting the position of the teeth of the die 39 that contact the workpiece) at least once during the face spline formation process. That is, the rotation direction of the die 39 about the reference axis C can be either forward, as shown in the order of (a1), (b1), and (c1) in FIG. 7, or reverse, as shown in the order of (a2), (b2), and (c2) in FIG. 7. When the rotation direction of the die 39 about the reference axis C is forward, stress concentration is likely to occur at the base portion P1 of the side surface of the protrusion 55 that is forward in the forward rotation direction, among the side surfaces on both sides in the circumferential direction. When the rotation direction of the mold 39 around the reference axis C is the reverse rotation direction, stress concentration is likely to occur at the base portion P2 of the front side surface of the convex portion 55 in the reverse rotation direction, among the side surfaces on both sides in the circumferential direction.

[0135] Therefore, in contrast to the conventional face spline molding method, the above-described face spline molding step prevents the problem of stress concentration occurring only at the base of one of both circumferential side surfaces of the protrusion 55 that constitutes the processed portion 42. This makes it easier to ensure the life of the stamping die 39. This is advantageous for reducing manufacturing costs and / or improving product quality.

[0136] For example, in the face spline forming process described above, the face spline forming process is divided into a rough forming process and a finish forming process following the rough forming process, and in the rough forming process, the number of times the pressing die 39 rotates in the forward direction is set to be substantially the same as the number of times the pressing die 39 rotates in the reverse direction. This makes it easy to ensure a sufficient lifespan of the pressing die 39.

[0137] In the face spline molding process, when reversing the rotation direction of the pressing die 39 about the reference axis C, it is necessary to temporarily stop the rotation of the pressing die 39 about the reference axis C. The more times the rotation direction of the pressing die 39 about the reference axis C is reversed, the longer the time required for the face spline molding process tends to become.

[0138] Therefore, by reversing the rotation direction of the mold 39 around the reference axis C only once in the rough forming process, the time required for the face spline forming process can be shortened compared to when the rotation direction is reversed two or more times.

[0139] In one example, the reversing operation (mode switching) is always performed at a predetermined circumferential position on the pressing die 39. For example, the reversing operation is performed for each revolution. In another example, the reversing operation (mode switching) is performed multiple times at different timings (circumferential positions). This prevents the reversing operation from concentrating at the same place.

[0140] The face spline molding method of the present disclosure is not limited to being applied to the formation of the hub-side face spline 12, but can also be applied to the formation of the joint-side face spline 25.

[0141] In one example, the face spline is formed at the crimped portion of the hub unit bearing. In another example, the face spline is formed at a portion of the hub unit bearing different from the crimped portion.

[0142] In one example, the face spline is formed on the hub unit bearing as a crimped assembly. In another example, the face spline is formed on a crimped assembly that is different from the hub unit bearing.

[0143] 9 and 10 are partial schematic diagrams of a vehicle 200 equipped with a hub unit bearing (bearing unit, bearing device) 151. The above-described hub unit bearing (caulked assembly) can be applied to both hub unit bearings for driving wheels and hub unit bearings for driven wheels. In FIG. 9, the hub unit bearing 151 is assembled to a suspension 192 of a vehicle body 190. In FIG. 10, the hub unit bearing 151 is for a driving wheel and includes an outer ring 152, a hub 153, and multiple rolling elements 156. The outer ring 152 is fixed to a knuckle 201 of a suspension device using bolts or the like. The wheel 202 (and the braking rotor 22) is fixed to a flange (rotating flange) 153A provided on the hub 153 using bolts or the like. The vehicle 200 can also have a support structure similar to that described above for the hub unit bearing 151 for the driven wheel.

[0144] The technical scope of the present invention is not limited to the scope of the embodiments. Various modifications or improvements can be made to the embodiments. Forms incorporating such modifications or improvements can also be included in the technical scope of the present invention. Furthermore, the present invention is not limited to the described embodiments, and any combination of these configurations may be used.

[0145] The present disclosure includes the following configurations and / or combinations:

[0146] In one aspect, a method for manufacturing a crimped assembly includes the steps of: preparing a first member having a crimped portion, wherein a second member is axially fixed to the first member by the crimped portion; setting a face spline die, wherein a central axis of the die is inclined with respect to a reference axis; and forming a face spline on the crimped portion of the first member using the die. The forming of the face spline includes the steps of: pressing the die against the crimped portion with a first relative motion between the die and the crimped portion, wherein the first relative motion moves a partial machining position on the crimped portion in a first circumferential direction; and pressing the die against the crimped portion with a second relative motion between the die and the crimped portion, wherein the second relative motion moves a partial machining position on the crimped portion in a second circumferential direction opposite to the first circumferential direction.

[0147] The method for manufacturing a crimped assembly according to the above aspect further includes a step of pressing the die against the crimped portion with a third relative motion between the die and the crimped portion, wherein the third relative motion moves a partial machining position on the crimped portion in a third circumferential direction, the third circumferential direction being opposite to the first circumferential direction or the second circumferential direction.

[0148] In the method for manufacturing a caulking assembly according to the above aspect, the relative speed in the third relative movement is different from at least one of the relative speed in the first relative movement and the relative speed in the second relative movement.

[0149] In the manufacturing method of the crimped assembly in the above aspect, before the pressing accompanied by the third relative movement, the pressing accompanied by the first relative movement and the pressing accompanied by the second relative movement are performed once or repeatedly performed multiple times.

[0150] In the method for manufacturing a caulking assembly according to the above aspect, the first relative motion and the second relative motion are performed in a rough forming stage of the face spline, and the third relative motion is performed in a finish forming stage of the face spline.

[0151] In another aspect, a method for manufacturing a mechanical device includes manufacturing a crimped assembly using the method for manufacturing a crimped assembly in the above aspect, and assembling the crimped assembly to a device body.

[0152] In another aspect, a method of manufacturing a hub unit bearing includes the steps of: setting a face spline die, wherein the central axis of the die is disposed at an angle with respect to a reference axis; and forming a face spline using the die on a hub body having rolling elements and an outer ring attached thereto. Forming the face spline includes the steps of: pressing the die against the hub body with a first relative motion between the die and the hub body, wherein the first relative motion moves a partial machining position on the hub body in a first circumferential direction; and pressing the die against the hub body with a second relative motion between the die and the hub body, wherein the second relative motion moves a partial machining position on the hub body in a second circumferential direction opposite to the first circumferential direction.

[0153] In the method for manufacturing a hub unit bearing according to the above aspect, forming the face spline includes rotating the outer ring relative to the hub body while pressing the die against the hub body.

[0154] In another aspect, a method for manufacturing a vehicle includes manufacturing a hub unit bearing using the method for manufacturing a hub unit bearing of the above aspect, and assembling the hub unit bearing to a vehicle body. The vehicle includes a hub unit bearing.

[0155] In another aspect, a manufacturing apparatus for a crimped assembly includes a first mechanism supporting a first member having a crimping portion, wherein a second member is axially fixed to the first member by the crimping portion, a second mechanism supporting a stamping die for a face spline, wherein a central axis of the stamping die is inclined with respect to a reference axis, a third mechanism pressing the stamping die against the crimping portion with relative motion between the stamping die and the crimping portion, and a control device. The control device has a first mode for performing a first relative motion between the stamping die and the crimping portion, wherein a partial machining position on the crimping portion moves in a first circumferential direction during the first relative motion, and a second mode for performing a second relative motion between the stamping die and the crimping portion, wherein the partial machining position on the crimping portion moves in a second circumferential direction opposite to the first circumferential direction during the second relative motion.

[0156] In another aspect, a mechanical device includes a crimped assembly manufactured using the crimped assembly manufacturing device of the above aspect, and a device body to which the crimped assembly is assembled.

[0157] In another aspect, a manufacturing apparatus for hub unit bearings includes a first mechanism that supports a hub body to which rolling elements and an outer ring are attached, a second mechanism that supports a stamping die for a face spline, the center axis of the stamping die being inclined with respect to a reference axis, a third mechanism that presses the stamping die against the hub body with relative motion between the stamping die and the hub body, and a control device. The control device has a first mode that performs a first relative motion between the stamping die and the hub body, in which a partial machining position on the hub body moves in a first circumferential direction during the first relative motion, and a second mode that performs a second relative motion between the stamping die and the hub body, in which a partial machining position on the hub body moves in a second circumferential direction opposite to the first circumferential direction during the second relative motion.

[0158] A vehicle in another aspect includes a hub unit bearing manufactured using the manufacturing method for a hub unit bearing of the above aspect, and a vehicle body to which the hub unit bearing is assembled.

[0159] In another aspect, a face spline forming method includes a face spline forming step of forming a face spline in a workpiece by pressing a portion of the processing portion against a circular annular processing portion provided coaxially with the workpiece while rotating the stamping die, the processing portion including a rotation axis and a processing portion formed by alternatingly arranging recesses and protrusions in a circumferential direction about the rotation axis and supported so as to be rotatable about the rotation axis, with the rotation axis tilted at a predetermined angle with respect to a central axis of the workpiece. The rotation direction of the stamping die about the central axis of the workpiece is reversed at least once during the face spline forming step.

[0160] In the face spline forming method according to the above aspect, the face spline forming process includes a rough forming process and a finish forming process subsequent to the rough forming process, and the rotation direction of the stamping die around the central axis of the workpiece is reversed at least once during the rough forming process but is not reversed during the finish forming process.

[0161] In the face spline forming method according to the above aspect, the rotation direction of the pressing die about the central axis of the workpiece is reversed only once during the rough forming step.

[0162] In the face spline forming method according to the above aspect, in the rough forming step, the rotation direction of the pressing die around the central axis of the workpiece is reversed every time the pressing die makes one rotation around the central axis of the workpiece.

[0163] In the face spline forming method according to the above aspect, in the rough forming step, the number of rotations of the stamping die in the forward rotation direction around the central axis of the workpiece is set to be the same as the number of rotations of the stamping die in the reverse rotation direction around the central axis of the workpiece.

[0164] In another aspect, in a method for manufacturing a hub unit bearing, the hub-side face spline is formed by the face spline molding method of the above aspect. The hub unit bearing includes an outer ring having multiple outer ring raceways on its inner peripheral surface, a hub having multiple inner ring raceways on its outer peripheral surface, and multiple rolling elements arranged in each row between the multiple outer ring raceways and the multiple inner ring raceways. The hub includes an inner ring having at least the axially innermost inner ring raceway of the multiple inner ring raceways on its outer peripheral surface, and a hub ring having a fitting shaft portion onto which the inner ring is externally fitted, a crimping portion that presses against an axially inner end face of the inner ring, and a hub-side face spline provided on an axially inner end face of the crimping portion.

[0165] In the method for manufacturing a hub unit bearing according to the above aspect, the outer ring is rotationally driven relative to the hub ring and the inner ring throughout the process of forming the hub-side face spline.

[0166] In another embodiment, a method for manufacturing a vehicle equipped with a hub unit bearing comprises manufacturing the hub unit bearing by the method for manufacturing a hub unit bearing as set forth in claim 6.

[0167] In another aspect, a method for manufacturing a mechanical device includes forming a face spline by the face spline forming method of the above aspect. The mechanical device includes a part having a face spline.

[0168] In another aspect, a face spline forming apparatus includes a die having a rotation axis and a processing portion formed by alternately arranging recesses and protrusions in a circumferential direction about the rotation axis, a die support mechanism that supports the die so that the die can rotate about the rotation axis with the rotation axis tilted at a predetermined angle with respect to a reference axis, and a control device. The control device controls a main shaft drive mechanism that rotates the die support mechanism about the reference axis and can reverse the direction of rotation, and controls the main shaft drive mechanism to rotate the die support mechanism about the reference axis while pressing a part of the processing portion of the die against a processed portion of a workpiece to form a face spline, thereby reversing the direction of rotation at least once during the process. [Explanation of symbols]

[0169] 1 Wheel drive unit 2 Hub unit bearing 3 Constant velocity joint 4 outer ring 5 Hub 6a, 6b rolling elements 7a, 7b Outer raceway 8 Stationary Flange 9 Flange side support hole 10a, 10b Inner raceway 11 Center hole 12 Hub side face spline 13 Rotating flange 14 Pilot Division 15 Mounting holes 16 Inner Circle 17, 17a, 17b hub wheels 18 Mating shaft 19, 19a Crimping part 20 Step surface 21a, 21b retainer 22 Joint outer ring 23 Joint inner ring 24 balls 25 Joint side face spline 26 Mouse section 27 Cylindrical part 28 Peripheral wall 29 Side wall 30 Outer diameter side engagement groove 31 Female thread 32 Inner diameter side engagement groove 33 Spline hole 34 volts 35 Shaft 36 Head 37 Cylindrical part 38 Face spline forming device 39 Press mold 40 Press mold support mechanism 41 Spindle drive mechanism 42 Processing Department 43 Shaft member 44 Die body 45 Die support block 46 Inner bearing device 47 frames 48 Outer bearing device 49 Die support recess 50 Support stand 51 Recess 52 Paddlewheel drive mechanism 53 Control device 54 Recess 55 Convex part 61 Support mechanism 100 molds 101 Processing Department 102 recess 103 Convex part 104 Crimping part 105 Hub side face spline

Claims

1. The first step involves preparing a first member having a crimped portion, wherein the second member is fixed axially to the first member by the crimped portion, The process involves setting up a mold for a face spline, wherein the central axis of the mold is positioned at an inclination with respect to a reference axis, and the process is as described above. A step of forming a face spline on the crimped portion of the first member using the press die, Equipped with, The formation of the aforementioned face spline is The process involves pressing the die against the crimping portion with a first relative movement between the die and the crimping portion, wherein in the first relative movement, a partial processing position on the crimping portion moves in a first circumferential direction. The process involves pressing the die against the crimping portion with a second relative motion between the die and the crimping portion, wherein in the second relative motion, the partial processing position on the crimping portion moves in a second circumferential direction opposite to the first circumferential direction, The process includes pressing the die against the crimping portion with a third relative movement between the die and the crimping portion, wherein the partial processing position on the crimping portion moves in a third circumferential direction during the third relative movement, The third circumferential direction is opposite to the first circumferential direction or the second circumferential direction. The relative velocity in the third relative motion is different from at least one of the relative velocity in the first relative motion and the relative velocity in the second relative motion. A method for manufacturing a crimped assembly.

2. Prior to the pressing accompanied by the third relative motion, the pressing accompanied by the first relative motion and the pressing accompanied by the second relative motion are performed once or repeatedly. A method for manufacturing a crimped assembly according to claim 1.

3. The first relative motion and the second relative motion are performed during the rough forming stage of the face spline. The third relative motion is performed during the finishing molding stage of the face spline. A method for manufacturing a crimped assembly according to claim 2.

4. A crimping assembly is manufactured using the method described in any one of claims 1 to 3, The crimping assembly is assembled to the main body of the device, A method for manufacturing a mechanical device that includes the following:

5. The process involves setting up a mold for a face spline, wherein the central axis of the mold is positioned at an inclination with respect to a reference axis, and the process is as described above. A step of forming a face spline on the hub body to which the rolling elements and outer ring are attached using the aforementioned mold, Equipped with, The formation of the aforementioned face spline is The process involves pressing the mold against the hub body with a first relative motion between the mold and the hub body, wherein the partial machining position on the hub body moves in a first circumferential direction during the first relative motion. The process involves pressing the mold against the hub body accompanied by a second relative motion between the mold and the hub body, wherein in the second relative motion, a partial machining position on the hub body moves in a second circumferential direction opposite to the first circumferential direction, The process involves pressing the mold against the hub body with a third relative motion between the mold and the hub body, wherein the partial machining position on the hub body moves in a third circumferential direction during the third relative motion. Includes, The third circumferential direction is opposite to the first circumferential direction or the second circumferential direction. The relative velocity in the third relative motion is different from at least one of the relative velocity in the first relative motion and the relative velocity in the second relative motion. A method for manufacturing a hub unit bearing.

6. The method for manufacturing a hub unit bearing according to claim 5, wherein the formation of the face spline includes rotating the outer ring relative to the hub body while pressing the mold against the hub body.

7. A method for manufacturing a vehicle equipped with a hub unit bearing, A hub unit bearing is manufactured using the method described in claim 5 or 6, The hub unit bearing is assembled to the vehicle body, A method for manufacturing a vehicle, comprising the following features.

8. A first mechanism supporting a first member having a crimped portion, wherein a second member is fixed axially to the first member by the crimped portion, A second mechanism for supporting a face spline die, wherein the central axis of the die is positioned at an inclination with respect to a reference axis, A third mechanism that presses the mold against the crimping portion with relative movement between the mold and the crimping portion, Control device and Equipped with, The control device has a first mode in which a first relative motion is performed between the press die and the crimping portion, wherein in the first relative motion, a partial processing position on the crimping portion moves in a first circumferential direction; a second mode in which a second relative motion is performed between the press die and the crimping portion, wherein in the second relative motion, a partial processing position on the crimping portion moves in a second circumferential direction opposite to the first circumferential direction; and a third mode in which a third relative motion is performed between the press die and the crimping portion, wherein in the third relative motion, a partial processing position on the crimping portion moves in a third circumferential direction. The third circumferential direction is opposite to the first circumferential direction or the second circumferential direction. The relative velocity in the third mode is different from at least one of the relative velocity in the first mode and the relative velocity in the second mode. Manufacturing equipment for crimped assemblies.

9. A crimping assembly manufactured using the apparatus described in claim 8, The device body to which the aforementioned crimping assembly is attached, A mechanical device equipped with the following features.

10. A first mechanism that supports the hub body to which the rolling elements and outer ring are attached, A second mechanism for supporting a face spline die, wherein the central axis of the die is positioned at an inclination with respect to a reference axis, A third mechanism that presses the mold against the hub body with relative motion between the mold and the hub body, Control device and Equipped with, The control device has a first mode in which a first relative motion is performed between the press die and the hub body, in which a partial machining position on the hub body moves in a first circumferential direction; a second mode in which a second relative motion is performed between the press die and the hub body, in which a partial machining position on the hub body moves in a second circumferential direction opposite to the first circumferential direction; and a third mode in which a third relative motion is performed between the press die and the hub body, in which a partial machining position on the hub body moves in a third circumferential direction. The third circumferential direction is opposite to the first circumferential direction or the second circumferential direction. The relative velocity in the third mode is different from at least one of the relative velocity in the first mode and the relative velocity in the second mode. Manufacturing equipment for hub unit bearings.

11. A hub unit bearing manufactured using the apparatus described in claim 10, The vehicle body to which the hub unit bearing is assembled, A vehicle equipped with the following features.

12. A step of preparing a first member having a crimping portion, wherein a second member is fixed axially to the first member by the crimping portion, The process involves setting up a mold for a face spline, wherein the central axis of the mold is positioned at an inclination with respect to a reference axis, and the process is as described above. A step of forming a face spline on the crimped portion of the first member using the press die, Equipped with, The formation of the aforementioned face spline is The process involves pressing the die against the crimping portion with a first relative movement between the die and the crimping portion, wherein in the first relative movement, a partial processing position on the crimping portion moves in a first circumferential direction. The process involves pressing the die against the crimping portion with a second relative motion between the die and the crimping portion, wherein in the second relative motion, the partial processing position on the crimping portion moves in a second circumferential direction opposite to the first circumferential direction, The process involves pressing the die against the crimping portion with a third relative motion between the die and the crimping portion, wherein in the third relative motion, a partial processing position on the crimping portion moves in a third circumferential direction. Includes, The third circumferential direction is opposite to the first circumferential direction or the second circumferential direction. The first relative motion and the second relative motion are performed during the rough forming stage of the face spline. The third relative motion is performed during the finishing molding stage of the face spline. A method for manufacturing a crimped assembly.

13. The relative velocity in the third relative motion is different from at least one of the relative velocity in the first relative motion and the relative velocity in the second relative motion. A method for manufacturing a crimped assembly according to claim 12.

14. The pressing accompanied by the third relative motion is performed once, or repeatedly multiple times, before the pressing accompanied by the first relative motion and the pressing accompanied by the second relative motion. A method for manufacturing a crimped assembly according to claim 12.

15. Manufacturing a crimped assembly using the method described in any one of Claims 12 to 14, The crimping assembly is assembled to the main body of the device, A method for manufacturing a mechanical device that includes the following:

16. A step of setting up a mold for a face spline, wherein the central axis of the mold is positioned at an inclination with respect to a reference axis, A step of forming a face spline on the hub body to which the rolling elements and outer ring are attached using the aforementioned mold, Equipped with, The formation of the aforementioned face spline is The process involves pressing the mold against the hub body with a first relative motion between the mold and the hub body, wherein the partial machining position on the hub body moves in a first circumferential direction during the first relative motion. The process involves pressing the mold against the hub body accompanied by a second relative motion between the mold and the hub body, wherein in the second relative motion, a partial machining position on the hub body moves in a second circumferential direction opposite to the first circumferential direction, The process includes pressing the mold against the hub body with a third relative motion between the mold and the hub body, wherein the partial machining position on the hub body moves in a third circumferential direction during the third relative motion, The third circumferential direction is opposite to the first circumferential direction or the second circumferential direction. The first relative motion and the second relative motion are performed during the rough forming stage of the face spline. The third relative motion is performed during the finishing molding stage of the face spline. A method for manufacturing a hub unit bearing.

17. The method for manufacturing a hub unit bearing according to claim 16, wherein the formation of the face spline includes rotating the outer ring relative to the hub body while pressing the mold against the hub body.

18. A method for manufacturing a vehicle equipped with a hub unit bearing, A hub unit bearing is manufactured using the method described in claim 16 or 17, The hub unit bearing is assembled to the vehicle body, A method for manufacturing a vehicle, comprising the following features.

19. A first mechanism for supporting a first member having a crimped portion, wherein a second member is fixed axially to the first member by the crimped portion, A second mechanism for supporting a face spline die, wherein the central axis of the die is positioned at an inclination with respect to a reference axis, A third mechanism that presses the mold against the crimping portion with relative movement between the mold and the crimping portion, Control device and Equipped with, The control device has a first mode in which a first relative motion is performed between the press die and the crimping portion, wherein in the first relative motion, a partial processing position on the crimping portion moves in a first circumferential direction; a second mode in which a second relative motion is performed between the press die and the crimping portion, wherein in the second relative motion, a partial processing position on the crimping portion moves in a second circumferential direction opposite to the first circumferential direction; and a third mode in which a third relative motion is performed between the press die and the crimping portion, wherein in the third relative motion, a partial processing position on the crimping portion moves in a third circumferential direction. The third circumferential direction is opposite to the first circumferential direction or the second circumferential direction. The first relative motion and the second relative motion are performed during the rough shaping stage of the face spline. The third relative motion is performed during the finishing molding stage of the face spline. Manufacturing equipment for crimped assemblies.

20. A crimping assembly manufactured using the apparatus described in Claim 19, The device body to which the aforementioned crimping assembly is attached, A mechanical device equipped with the following features.

21. A first mechanism supporting a hub body to which rolling elements and an outer ring are attached, A second mechanism for supporting a face spline die, wherein the central axis of the die is positioned at an inclination with respect to a reference axis, A third mechanism that presses the mold against the hub body with relative motion between the mold and the hub body, Control device and Equipped with, The control device has a first mode in which a first relative motion is performed between the press die and the hub body, in which a partial machining position on the hub body moves in a first circumferential direction; a second mode in which a second relative motion is performed between the press die and the hub body, in which a partial machining position on the hub body moves in a second circumferential direction opposite to the first circumferential direction; and a third mode in which a third relative motion is performed between the press die and the hub body, in which a partial machining position on the hub body moves in a third circumferential direction. The third circumferential direction is opposite to the first circumferential direction or the second circumferential direction. The first relative motion and the second relative motion are performed during the rough shaping stage of the face spline. The third relative motion is performed during the finishing molding stage of the face spline. Manufacturing equipment for hub unit bearings.

22. A hub unit bearing manufactured using the apparatus described in Claim 21, The vehicle body to which the hub unit bearing is assembled, A vehicle equipped with the following features.

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