JP2017018991A - Manufacturing method of rolling bearing unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a manufacturing method which can suppress a manufacturing cost while securing the durability of a rolling bearing unit.SOLUTION: A plurality of punch elements 46, 46 which are divided into a plurality of pieces in a circumferential direction, displaceable in an axial direction, and hindered in displacement to a peripheral direction are assembled, and one end face in the axial direction of a molding punch 39 having processing teeth 44, 44 at the one end face in the axial direction is made to oppose the other end face of a caulked part 20 in the axial direction. In this state, a roll 30a is rotated with a center axis α of a hub main body 8 as a center while pressing the other end face of the molding punch 39 in the axial direction by a pressing face 43 of the roll 30a having a center axis β which is inclined to the center axis α of the hub main body 8.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a method for manufacturing a rolling bearing unit that is used as a wheel bearing rolling bearing unit that constitutes a wheel driving bearing unit, for example, in combination with a constant velocity joint.

  FIG. 9 shows an example of a conventional structure of a wheel driving bearing unit incorporating a wheel supporting rolling bearing unit, which is a kind of rolling bearing unit that is an object of the present invention. Show. The wheel drive bearing unit shown in FIG. 9 is formed by combining a wheel support rolling bearing unit 1 and a constant velocity joint outer ring 2. Of these, the wheel support rolling bearing unit 1 includes an outer ring 3, a hub 4, and a plurality of rolling elements (balls in the illustrated example) 5 and 5.

  Of these, the outer ring 3 has a stationary flange 6 on the outer peripheral surface and double row outer ring raceways 7a and 7b on the inner peripheral surface. The hub 4 is formed by combining a hub body 8 and an inner ring 9. Of these, the hub body 8 has a rotation-side flange 10 at a portion near one end of the outer peripheral surface in the axial direction, an inner ring raceway 11a on one axial side in the same axial direction, and a small-diameter step 12 at the other end in the same axial direction. Each has a central hole 13 in the center. In this specification, “one side” with respect to the axial direction means the outside in the width direction of the vehicle in the assembled state to the automobile, the left side of FIG. 9, the lower side of FIGS. The right side of FIG. 9 and the upper side of FIGS. 1 to 4 and 6, which are the center side of the vehicle when assembled to an automobile, are referred to as “other side” with respect to the axial direction. At one end portion in the axial direction of the center hole 13, there is a small diameter portion 14 through which the flange portion 16 of the bolt 15 as a coupling member can be inserted through a predetermined guide gap. The inner ring 9 has an inner ring raceway 11b on the outer peripheral surface on the other side in the axial direction, and is externally fitted to the small-diameter step portion 12 of the hub body 8 with an interference fit. Further, a plurality of rolling elements 5, 5 are provided between the outer ring raceways 7a, 7b and the inner ring raceways 11a, 11b so as to be freely rollable in both rows. Further, in this state, of the cylindrical portion 19 provided at the other axial end of the hub body 8, the portion protruding from the other axial opening of the inner ring 9 is caulked by plastic deformation outward in the radial direction. Part 20 is formed. Then, by pressing the other end surface in the axial direction of the inner ring 9 with the caulking portion 20, an appropriate preload is applied to the rolling elements 5 and 5. Further, a hub-side face spline 21 that is an uneven portion in the circumferential direction is formed on the other end surface in the axial direction of the caulking portion 20 over the entire circumference. In the case of the illustrated example, the tooth tip surface of the hub-side face spline 21 is a plane perpendicular to the central axis of the hub body 8.

  The constant velocity joint outer ring 2 includes a cup-shaped mouth portion 22, an end wall portion 23 which is a bottom portion of the mouth portion 22, and a cylinder extending in one axial direction from the center portion of the end wall portion 23. And a central hole of the shaft portion 24 is a screw hole 25. In addition, a joint-side face spline 26 that is an uneven portion in the circumferential direction is formed over the entire circumference of the end wall portion 23 on the outer peripheral portion of one axial end surface. In the illustrated example, the tooth tip surface of the joint-side face spline 26 is a plane perpendicular to the central axis of the constant velocity joint outer ring 2. The number of teeth of the joint-side face spline 26 is the same as the number of teeth of the hub-side face spline 21.

  Then, the hub body 8 and the joint-side face splines 21 and 26 are engaged with each other while the central axes of the hub body 8 and the constant velocity joint outer ring 2 are aligned with each other. The rotational force can be transmitted to and from the outer ring 2 for the constant velocity joint. In this state, the flange portion 16 of the bolt 15 is inserted into the small diameter portion 14 of the center hole 13 of the hub body 8 from one side in the axial direction, and the male screw portion 17 provided at the tip portion of the flange portion 16 is It is screwed into the screw hole 25 and further tightened. Accordingly, the hub body 8 and the constant velocity joint outer ring 2 are coupled and fixed in a state where the hub body 8 is sandwiched between the head 18 of the bolt 15 and the constant velocity joint outer ring 2. .

  When the wheel drive bearing unit configured as described above is assembled to a vehicle, the stationary side flange 6 of the outer ring 3 is coupled and fixed to a suspension device, and the wheel (drive wheel) is attached to the rotation side flange 10 of the hub body 8. ) And a brake rotating member such as a disk. Further, a tip end portion of a drive shaft (not shown) that is rotationally driven by the engine via the transmission is spline-engaged with the inside of the constant velocity joint inner ring 27 provided inside the constant velocity joint outer ring 2. When the automobile travels, the rotation of the constant velocity joint inner ring 27 is transmitted to the constant velocity joint outer ring 2 and the hub main body 8 via a plurality of balls 28 to rotate the wheels.

  When assembling the wheel support rolling bearing unit 1 constituting the wheel drive bearing unit configured as described above, first, the outer ring 3 is disposed around the hub body 8, and the outer ring raceways 7a, 7b, between the outer ring raceway 7a on one axial side and the inner ring raceway 11a on one axial side, the rolling elements 5, 5 are provided in a state of being held by a cage 29a on one axial side. Next, the rolling elements 5 and 5 are installed around the inner ring raceway 11b on the other axial side formed on the outer peripheral surface of the inner ring 9 while being held by the cage 29b on the other axial side. Then, the inner ring 9 is externally fitted to the small-diameter step portion 12 formed at the other axial end portion of the hub body 8 with an interference fit. Then, along with this external fitting operation, the rolling surface of each of the rolling elements 5, 5 (in the other axial row) held by the cage 29 b on the other axial side is connected to the other axial end of the outer ring 3. It is made to contact | abut to the outer ring | wheel track | orbit 7b of the other axial direction formed in the inner peripheral surface of a shift | offset | difference part. Next, the cylindrical portion 19 formed at the other axial end portion of the hub body 8 is plastically deformed radially outward to form the caulking portion 20. The inner ring 9 is fixed to the hub body 8 by pressing the other axial end surface of the inner ring 9 in the axial direction by the caulking portion 20.

  Further, as shown in FIG. 10, a center inclined at a predetermined angle θ with respect to the central axis (the central axis of the wheel bearing rolling bearing unit 1) α of the hub body 8 at the other axial end surface of the caulking portion 20. The hub-side face spline 21 is formed by performing rocking forging using a roll 30 having an axis β. In FIG. 10, members other than the hub body 8 (outer ring 3, rolling elements 5, 5, inner ring 9, etc.) are omitted from the members constituting the wheel support rolling bearing unit 1. . The front end surface of the roll 30 (lower end surface in FIG. 10) is a processing surface 31 in which convex portions (processing teeth) 33 and 33 and concave portions 34 (see FIG. 12) are alternately arranged over the entire circumference. Yes. The roll 30 is rotated around the central axis α of the hub body 8 in a state where the processed surface 31 of the roll 30 is pressed against the other axial end surface of the caulking portion 20. Here, the roll 30 is supported so as to be rotatable about its own central axis β. Therefore, in a state before the hub-side face spline 21 (uneven portion related to the circumferential direction to be formed) is formed on the other end surface in the axial direction of the caulking portion 20, the roll 30 is moved to the central axis of the hub body 8. When rotated about α, the roll 30 is moved to its central axis based on the frictional engagement between the tip surfaces of the projections 33 and 33 provided on the processing surface 31 and the other axial end surface of the caulking portion 20. Rotates (rotates) around β. On the other hand, after the hub side face spline 21 is formed to some extent (the tooth length of the hub side face spline 21 has increased to some extent), the roll 30 is rotated around the central axis α of the hub body 8. Then, the roll 30 rotates based on the engagement (meshing) of the concave portion 34 and the convex portions 33 and 33 constituting the processed surface 31 with the hub-side face spline 21. With such a configuration, the hub-side face spline 21 is formed on the other axial end surface of the caulking portion 20 by plastically deforming the other axial end surface of the caulking portion 20, and the hub-side face spline 21 is further formed. Increase the tooth height and complete the processing.

  The manufacturing method of the wheel-supporting rolling bearing unit 1 as described above has room for improvement in terms of reducing the manufacturing cost while ensuring the durability of the wheel-supporting rolling bearing unit 1. That is, the operation of forming the hub-side face spline 21 (oscillating forging) is performed in a state in which the processing surface 31 of the roll 30 is pressed against the other end surface in the axial direction of the caulking portion 20 with a large force (pressing force) F. The roll 30 is rotated by rotating around the central axis α of the hub body 8. In such a swing forging, if the inclination angle θ of the central axis β of the roll 30 with respect to the central axis α of the hub body 8 is small, the processing surface 31 of the roll 30 and the axial direction of the caulking portion 20 The contact area with the other end surface, that is, the contact area between the tip surfaces of the convex portions 33 and 33 constituting the processed surface 31 and the other end surface in the axial direction of the caulking portion 20 is increased. As a result, a load applied to the other end surface in the axial direction of the caulking portion 20 from the tip surface of each of the convex portions 33, 33 (of the portion that should become the tooth bottom of the hub-side face spline 21) (the convex portions 33). , 33 and the contact surface pressure between the other end surface in the axial direction of the caulking portion 20) are reduced. Therefore, when the inclination angle θ is small, it is necessary to increase the pressing force F to ensure a load applied from the front end surfaces of the convex portions 33 and 33 to the other end surface in the axial direction of the caulking portion 20. . FIG. 11 shows the relationship between the inclination angle θ and the maximum value of the pressing force F. As is apparent from FIG. 11, when the inclination angle θ is 5 degrees, a pressing force F that is about twice that when the inclination angle θ is 15 degrees is required. When this pressing force F is increased, the processing apparatus used for the rocking forging increases in size, thereby increasing the manufacturing cost.

  On the other hand, when the inclination angle θ is large, the straightness of the cross-sectional shape of the tooth surfaces (tooth side surfaces) of the teeth 32 constituting the hub-side face spline 21 is lowered. That is, in the case of the conventional method of manufacturing the wheel support rolling bearing unit 1 as described above, among the plurality of recesses 34 constituting the processing surface 31 of the roll 30, the central position of one recess 34 (this A state in which the center position of the roll 30 in the circumferential direction is pressed against the other end face in the axial direction of the caulking portion 20 (passing through the center position of the one recess 34 and parallel to the center axis β of the roll 30) In the imaginary plane including the central axis α of the hub body 8 and the central axis β), the tooth surface of the tooth 32 formed by the one concave portion 34 (to be the tooth 32). As shown in FIG. 12C, the inner side surface of the one concave portion 34 (the side surface in the circumferential direction of the roll 30) in which the circumferential surface of the convex portion abuts on the tooth surface of the tooth 32. ) And parallel. From this state, when the roll 30 is rotated (revolved) around the central axis α, the inner surface of the one recess 34 is the tooth surface of the tooth 32 formed by the one recess 34 (the relevant It is inclined with respect to the circumferential side surface of the convex portion to be the tooth 32. The inclination angle of the circumferential side surface of the single concave portion 34 with respect to the tooth surface of the tooth 32 is that of the convex portion 33 of the plurality of convex portions 33 and 33 constituting the processing surface 31 of the roll 30. It becomes the largest in the state {state shown in (B) or (D) of FIG. 12} in which the center position is pressed against the other end surface in the axial direction of the caulking portion 20. The inclination angle of the inner surface of the recess 34 with respect to the tooth surface of the tooth 32 increases as the inclination angle θ of the central axis β of the roll 30 with respect to the central axis α of the hub body 8 increases. When the inclination angle of the inner surface of the recess 34 with respect to the tooth surface of the tooth 32 increases, the circumferential side surface of the one recess 34 and the tooth surface of the tooth 32 locally contact each other. The tooth surface of the tooth 32 is locally plastically deformed. As a result, the radius of curvature of the cross-sectional shape of the tooth surface of the tooth 32 becomes smaller, as in the portion surrounded by the chain line δ in FIG. 35 is formed, and the straightness of the cross-sectional shape of the tooth surface of the tooth 32 is lowered. When this straightness decreases, the hub side face spline 21 is configured in a state where the hub side face spline 21 and the joint side face spline 26 (see FIG. 9) formed on the constant velocity joint outer ring 2 are engaged with each other. The contact area between the tooth surfaces of the teeth 32 and the teeth constituting the joint-side face spline 26 is reduced, and the meshing portion of the hub-side face spline 21 and the joint-side face spline 26 is extended. There is a possibility that it is difficult to ensure the durability of the entire wheel bearing rolling bearing unit 1.

JP 2009-292422 A

  In view of the circumstances as described above, the present invention was invented to realize a method of manufacturing a rolling bearing unit that can reduce the manufacturing cost while ensuring the durability of the rolling bearing unit.

A rolling bearing unit that is an object of the manufacturing method of the present invention includes a hub body and an inner ring.
Of these, the hub main body has an inner ring raceway on one axial side on the outer peripheral surface of the axially intermediate portion.
The inner ring has an inner ring raceway on the other side in the axial direction on the outer peripheral surface, and is externally fitted to a portion near the other end of the hub body in the axial direction.
Then, the other end surface in the axial direction of the inner ring is held down by a caulking portion formed by plastically deforming a cylindrical portion provided at the other end portion in the axial direction of the hub main body in a radially outward direction, and the inner ring is connected to the hub main body. It is fixed to support. Also, a hub-side face spline that is a concavo-convex portion in the circumferential direction is formed on the other end surface in the axial direction of the caulking portion.
More specifically, the rolling bearing unit that is the object of the manufacturing method of the present invention as described above includes an outer ring having double-row outer ring raceways on the inner peripheral surface, and a space between these outer ring raceways and the both inner ring raceways. In addition, a plurality of rolling elements provided in a freely rotatable manner are provided.

  Further, the method of manufacturing a rolling bearing unit according to the present invention includes a plurality of punch elements that are divided into a plurality of parts in the circumferential direction, each of which is capable of axial displacement and is prevented from being displaced in the circumferential direction. The axial direction one end surface of the forming punch which formed the same number of teeth as the number of teeth of the hub side face spline on the one axial end surface is opposed to the other axial end surface of the caulking portion. In this state, the other end surface in the axial direction of the molding punch is pressed by a conical or conical pressing surface of a roll having a central axis inclined with respect to the central axis of the hub body, Rotate around the center axis of the hub body. By such a process, the hub-side face spline is formed on the other axial end surface of the caulking portion.

  In the case of carrying out the rolling bearing unit manufacturing method of the present invention as described above, preferably, the inclination angle of the central axis of the roll with respect to the central axis of the hub body is 15 degrees as in the invention described in claim 2. That's it. In this case, the inclination angle is preferably 30 degrees or less.

Further, when the method for manufacturing the rolling bearing unit of the present invention as described above is carried out, the molding punch is preferably divided into the same number as the number of teeth of each machining tooth as in the invention described in claim 3. It is assumed that each punch element is made. Specifically, each of these punch elements is divided for each processing tooth {divided at the center position of the tooth bottom existing between adjacent processing teeth (the center position in the circumferential direction of the forming punch)}. Or it shall be divided | segmented in the center position of the tooth tip of each said processing tooth.
When the invention described in claim 3 is carried out, preferably, as in the invention described in claim 4, the circumferential direction of the other axial end face of one of the punch elements The center axis of the hub body of the one punch element in the state where the rear edge in the rotation direction of the roll centering on the center axis of the hub body is pressed by the pressing surface of the roll, Among the circumferential opposite side edges of the other end face in the axial direction of the punch element existing on the front side in the rotational direction of the roll with the center at the center, the rear side edge in the rotational direction of the roll around the central axis of the hub body (the above-mentioned One punch element side edge) is not pressed by the pressing surface of the roll. In other words, among the circumferential side surfaces of the one punch element, the rear surface in the rotational direction of the roll centered on the central axis of the hub main body, the central axis of the hub main body, and the central axis of the roll The other end surface in the axial direction of the punch element existing on the front side in the rotation direction of the roll around the central axis of the hub body of the one punch element in a state where a virtual plane including the same exists on the same plane The side edge on the one punch element side and the pressing surface of the roll are in contact or close to each other in the circumferential direction on both sides (the axis of the punch element existing on the front side in the rotation direction of the roll). The pressing amount by the pressing surface of the roll (the pressing amount in the axial direction of the hub body) is adjusted so that the other end surface in the direction is not strongly pressed.

  Preferably, when carrying out the manufacturing method of the rolling bearing unit of the present invention as described above, the hub side face spline formed on the other end face in the axial direction of the caulking portion is formed as in the invention described in claim 5. In a state where the tooth height of the teeth constituting a desired size is reached, a part of each of the punch elements is abutted against a stepped surface portion provided in a portion for holding the punch elements, so that each of the punch elements Prevents further displacement in the other axial direction.

According to the manufacturing method of the rolling bearing unit of the present invention configured as described above, the manufacturing cost can be suppressed while ensuring the durability of the rolling bearing unit.
That is, in the case of the present invention, in the state where one axial end surface of the molding punch is opposed to the other axial end surface of the caulking portion, the axial end of the molding punch is inclined with respect to the central axis of the hub body. The roll is rotated around the central axis of the hub body while being pressed by the pressing surface of the roll having the. As a result, the processing teeth formed on one axial end surface of the forming punch are pressed against the other axial end surface of the caulking portion, and the hub side face spline is formed on the other axial end surface of the caulking portion. Here, in the case of the present invention, the plurality of punch elements constituting the forming punch are allowed to be displaced in the axial direction and are prevented from being displaced in the circumferential direction. Therefore, in the case of the present invention, when the hub side face spline is formed, each of the processed teeth can be prevented from being inclined with respect to the tooth surface of the tooth constituting the hub side face spline. Generation of local contact between the processing surface of the roll and the end surface in the axial direction of the caulking portion such that the tooth surface of the teeth constituting the face spline is locally plastically deformed can be prevented. Therefore, the straightness of these teeth can be improved, and the durability of the rolling bearing unit can be sufficiently ensured. In addition, it is possible to suppress the force that presses the pressing surface of the roll toward the other side in the axial direction, and to prevent the processing apparatus used for processing for forming the hub-side face spline from being enlarged, thereby reducing the manufacturing cost. Increase can be suppressed.

Sectional drawing which shows one example of the rocking press apparatus which can implement the manufacturing method of one example of embodiment of this invention in the state before starting the process for forming a hub side face spline. Sectional drawing similarly shown in the state in process. Sectional drawing similarly shown in the state of processing completion. FIG. 2A is an enlarged view (A) of FIG. 2 and FIG. 3 is an enlarged view (B) of a portion b of FIG. The perspective view (A) which takes out and shows one punch element, The top view (B) seen from the upper part of (A), and cc sectional drawing (C) of (B). The side view (A) which takes out and shows a roll and a forming punch, and the d section enlarged view (B) of (A). The figure (A) which shows typically the cross section of the contact part of the press surface of a roll, and the axial direction other end surface of a shaping | molding punch, and the figure (B) which shows the state seen from the left of (A). The figure similar to FIG. 5 which shows another example of a punch element. Sectional drawing which shows an example of the conventional structure of the wheel drive bearing unit incorporating the wheel support bearing unit which is 1 type of the rolling bearing used as the object of this invention. Sectional drawing which shows one example of the manufacturing method of the conventional wheel drive bearing unit. The diagram which shows the relationship between the inclination angle of the center axis | shaft of the roll with respect to the center axis | shaft of a hub main body, and the maximum value of the pressing force F. FIG. The schematic diagram which shows the state which forms a hub side face spline by rocking forge. A schematic diagram (A) showing the face spline teeth formed by rocking forging with the inclination angle of the central axis of the roll with respect to the central axis of the hub body being 5 degrees, and a schematic view when the inclination angle is similarly 15 degrees. Figure (B).

  An example of an embodiment of the present invention will be described with reference to FIGS. It should be noted that the features of the present invention including this example are the axial direction of the caulking portion of the hub body constituting the rolling bearing unit in order to reduce the manufacturing cost while ensuring the durability of the wheel bearing rolling bearing unit 1. The method is to devise a method of forming a hub-side face spline on the end face. Conventionally, the procedures for manufacturing each member constituting the wheel bearing rolling bearing unit 1 by subjecting a metal material to plastic working such as forging, finishing such as turning, and finishing such as polishing have been widely known. Since it is the same as the manufacturing method of the rolling bearing unit currently used, description is abbreviate | omitted.

  Also in this example, as in the conventional manufacturing method described above, the outer ring 3 is arranged around the hub body 8, and a plurality of outer ring raceways 7a on one axial side and a plurality of inner ring raceways 11a on one axial side are provided. These rolling elements 5 and 5 are provided in a state of being held by a cage 29a (see FIG. 9) on one axial side. Next, the rolling elements 5, 5 are installed around the inner ring raceway 11b on the other axial side formed on the outer peripheral surface of the inner ring 9 in a state of being held by the cage 29b on the other axial side, and in this state, the inner ring 9 is externally fitted to the small-diameter step portion 12 formed at the other axial end portion of the hub body 8 by an interference fit. Then, the outer ring raceway on the other side in the axial direction in which the rolling surfaces of the rolling elements 5 and 5 in the other row in the axial direction are formed on the inner peripheral surface near the other end in the axial direction of the outer ring 3 in accordance with this outer fitting work. 7b. Next, the caulking portion 20 is formed by plastically deforming the cylindrical portion 19 formed at the other axial end portion of the hub body 8 radially outward. Then, the other end surface in the axial direction of the inner ring 9 is held in the axial direction by the caulking portion 20, and the inner ring 9 is fixed to the hub body 8. Further, a hub-side face spline 21 (see FIG. 9) is formed on the other axial end surface of the caulking portion 20.

  The swing forging for forming the hub-side face spline 21 is performed using a swing press device 36 as shown in FIGS. The swing press device 36 includes a base 37, a holder 38 supported and fixed on the other side surface in the axial direction of the base 37, a roll 30 a, a forming punch 39, and a punch lifting mechanism 40. Of these, the holder 38 is provided with a holding recess 42 on the other side surface in the axial direction, which is provided at one axial end portion of the hub body 8 and into which a cylindrical portion 41 called a pilot portion can be inserted without rattling. The roll 30a is supported so as to be able to rotate (rotate) about its own central axis β inclined by a predetermined angle θ with respect to the central axis α of the hub body 8, and has a distal end surface (FIG. 1). 3 (lower end surface) is a truncated cone-shaped pressing surface 43. In the case of this example, the predetermined angle θ is set to 15 degrees or more and 30 degrees or less (15 ≦ θ ≦ 30).

  The molding punch 39 is formed in a substantially cylindrical shape as a whole, and has the same number of machining teeth 44, 44 as the number of teeth of the hub-side face spline 21 on one end face in the axial direction at equal intervals in the circumferential direction. A flange portion 45 protruding radially outward is provided over the entire circumference in the axially intermediate portion of the outer peripheral surface. Such forming punch 39 is divided into each of the machining teeth 44, 44 in the same number as each of the machining teeth 44, 44 (the center position of the tooth base existing between the machining teeth 44, 44). The punch elements 46 and 46 are divided by (1). In other words, the shape of the forming punch 39 when viewed from the axial direction is a sector shape, and an element main body 47 in which one machining tooth 44 is provided on one axial end surface, and the axial direction of the outer peripheral surface of the element main body 47 A punch element 46 composed of a projecting portion 48 provided at an intermediate portion is combined in the circumferential direction. In the forming punch 39 having such a configuration, the punch holding plates 49 constituting the punch lifting mechanism 40 allow the punch elements 46 and 46 to be displaced only in the axial direction with respect to the punch holding plate 49. It is supported by.

  The punch raising / lowering mechanism 40 is for raising and lowering the forming punch 39 (displacement in the axial direction of the hub main body 8), and between the punch holding plate 49 and the punch holding plate 49 and the base 37. The hydraulic cylinders 50 and 50 provided are provided. Among these, the punch holding plate 49 is provided with a holding hole 51 at the center for holding the forming punch 39 in the radial direction and the circumferential direction without rattling. The holding hole 51 is provided with a stepped surface portion 52 that allows a small diameter portion on one side in the axial direction and a large diameter portion on the other side in the axial direction to be continuous in the intermediate portion in the axial direction. In addition, the dimension in the axial direction of the large diameter portion is larger than the dimension (thickness) in the axial direction of the flange portion 45 of the molding punch 39. In addition, an annular closing plate 53 is supported and fixed around the other axial opening of the holding hole 51 in a state where the axial half of the forming punch 39 is inserted into the holding hole 51. Such a punch holding plate 49 is supported by the hydraulic cylinders 50 and 50 so as to be movable up and down with respect to the base 37 (position adjustment in the axial direction is possible).

  When performing rocking forging in which the hub side face spline 21 is formed on the other axial end surface of the caulking portion 20 using the rocking press device 36 as described above, first, as shown in FIG. By operating each of the hydraulic cylinders 50, 50, the punch holding plate 49, the axial end surface of the molding punch 39 held by the punch holding plate 49, and the wheel support rolling held by the holder 38 are used. The bearing unit 1 is positioned vertically upward so that it does not come into contact with the other axial end surface (the other axial end surface of the caulking portion 20). In this state, one end surface in the axial direction of the flange portion 45 of the molding punch 39 abuts on a step surface portion 52 provided in the intermediate portion in the axial direction of the holding hole 51, and the other axial end surface of the flange portion 45, A gap is interposed between the closing plate 53 and the radially inner end portion of one side surface in the axial direction. Further, the wheel-supporting rolling bearing unit 1 is rattled by the holder 38 in a state in which the cylindrical portion (pilot portion) 41 of the hub body 8 is inserted into the holding recess 42 of the holder 38 without rattling. Keep without.

Next, each of the hydraulic cylinders 50, 50 is operated to displace the punch holding plate 49 downward, and one axial end surface of the forming punch 39 held on the punch holding plate 49 and the caulking portion 20 The other axial end surface is brought into contact. From this state, the punch holding plate 49 is further displaced downward to displace the forming punch 39 in the other axial direction with respect to the holding plate 49, as shown in FIG. 2 and FIG. The other end surface in the axial direction of the flange portion 45 of the molding punch 39 is brought into contact with a portion closer to the inner diameter of one side surface in the axial direction of the closing plate 53. In this state, a gap 54 {see FIG. 4A} is interposed over the entire circumference between one axial end surface of the flange portion 45 and the stepped surface portion 52 of the holding hole 51. . In the case of the present example, the axial dimension L ₅₄ of the gap 54, the teeth 32 of the hub-side face splines 21 so as to be the same as the tooth depth (see FIG. 12), the flange portion 45 and the The axial dimension of the holding hole 51 is restricted. Next, the ram supporting the roll 30 a is lowered, and the pressing surface 43 of the roll 30 a is brought into contact with the other axial end surface of the forming punch 39.

  The other end surface in the axial direction of the forming punch 39, that is, the other end surface in the axial direction of the punch elements 46 and 46 constituting the forming punch 39 is directed toward one side in the axial direction by the pressing surface 43 of the roll 30a. In the pressed state, the roll 30a is rotated about the central axis α of the hub body 8. Thereby, each said punch element 46 and 46 contacted | abutted with the press surface 43 of this roll 30a is pressed toward one axial direction, and the process teeth 44 formed in the axial direction one end surface of these each punch elements 46 and 46, 44 is pressed against the other end surface in the axial direction of the caulking portion 20, and the other end surface in the axial direction of the caulking portion 20 is plastically deformed. The punch elements 46, 46 pressed by the pressing surface 43 of the roll 30 a are rotated by the roll 30 a about the central axis α of the hub body 8. The circumferential direction shifts in the same direction as the revolution direction. In the case of this example, as shown in FIG. 6, the center of the hub body 8 is the center of the hub body 8 out of both circumferential edges of the other axial end face of the punch element 46. The rotation direction of the roll 30a about the axis α (the direction of the arrow λ in FIG. 6B) with the rear edge ζ pressed by the pressing surface 43 of the roll 30a, the one punch element 46, both ends in the circumferential direction of the other axial end face of the punch element 46 existing on the front side in the rotational direction of the roll 30a (right side in FIG. 6B) around the central axis α of the hub body 8. Of these, the side edge on the one punch element 46 side (the side edge on the rear side in the rotation direction of the roll 30a around the central axis α) η is not pressed by the pressing surface 43 of the roll 30a. ing. Specifically, among the circumferential side surfaces of the one punch element 46, the rear side surface in the rotation direction of the roll 30a centered on the central axis α of the hub body 8, and the central axis α and the roll Punch element existing on the front side in the rotation direction of the roll 30a around the central axis α of the one punch element 46 in a state where a virtual plane including the central axis β of 30a exists on the same plane Of the two circumferential edges of the other end face in the axial direction of 46, the side edge η on the one punch element 46 side and the pressing face 46 of the roll 30a are kept in contact or close to each other. Therefore, the pressing amount Δd of the other end surface in the axial direction of the one punch element 46 by the pressing surface 43 of the roll 30a per one rotation of the roll 30a around the central axis α of the hub body 8 is determined. It is adjusting.

この（１）式を変形すると、次の（２）式が得られる。

The magnitude of the pressing amount Δd will be described with reference to FIGS. FIG. 7A schematically shows a cross section of a contact portion between the pressing surface 43 of the roll 30 a and one axial end surface of the forming punch 39. 7B shows the state of FIG. 7A viewed from the left side, that is, the outer shape of the pressing surface 43 of the roll 30a, the origin, the pressing surface 43 of the roll 30a and the molding. A radial outer end portion of the abutting portion with the one end surface of the punch 39 in the axial direction, and the x-axis of the x-axis and the y-axis orthogonal to each other is the front-back direction of FIG. It is represented by an xy coordinate system matched with the axial direction of the body 8. 7A and 7B, R represents the outer diameter of the contact portion between the pressing surface 43 of the roll 30a and one axial end surface of the forming punch 39, and r (= R cos θ) is the same. The maximum radius of the pressing surface 43 (the dimension between the outer peripheral edge of the contact portion and the central axis β of the roll 30a) is shown. In the xy coordinate system, the outer shape of the pressing surface 43 is expressed by the following equation (1).

When this equation (1) is modified, the following equation (2) is obtained.

この様な（３）式で表される幅Ｌ_４６を前記（２）式に代入する事で、前記１個のパンチ素子４６の軸方向他端面の円周方向両側縁のうち、前記中心軸αを中心とする前記ロール３０ａの回転方向後側縁ζを、このロール３０ａの押圧面４３により押圧した状態で、前記１個のパンチ素子４６の、前記中心軸αを中心とする前記ロール３０ａの回転方向前側（図６の左側）隣りに存在するパンチ素子４６の軸方向他端面の円周方向両側縁のうち、前記１個のパンチ素子４６側の側縁ηと、前記ロール３０ａの押圧面４３とが接触する、押圧量Δｄ_ｍａｘ（前記ロール３０ａの、前記ハブ本体８の中心軸αを中心とする１回転当たりの前記各パンチ素子４６、４６の押圧量Δｄの上限値）を近似的に求める事ができる。本例の場合、具体的には、前記傾斜角度θが１５〜３０度である場合、前記押圧量Δｄを０．１３〜０．３［ｍｍ］に調整する。 Here, the maximum value _{L 46} of the width of the punch element 46, 46 (the width in the circumferential direction of the forming punch 39), when the total number of each of these punch elements 46, 46 is N, the following (3) It is expressed by a formula.

By substituting the width L ₄₆ represented by the equation (3) into the equation (2), the central axis of the circumferentially opposite side edges of the other axial end surface of the one punch element 46 can be obtained. The roll 30a about the central axis α of the one punch element 46 in a state in which the rotation direction rear side edge ζ about the roll 30a is pressed by the pressing surface 43 of the roll 30a. Of the circumferentially opposite side edges of the other end face in the axial direction of the punch element 46 that is adjacent to the front side in the rotational direction (left side in FIG. 6) and the side edge η on the one punch element 46 side and the pressure of the roll 30a Approximate the pressing amount Δd _max (the upper limit value of the pressing amount Δd of each of the punch elements 46 and 46 per rotation around the central axis α of the hub body 8 of the roll 30a) with which the surface 43 comes into contact. Can be requested. In the case of this example, specifically, when the inclination angle θ is 15 to 30 degrees, the pressing amount Δd is adjusted to 0.13 to 0.3 [mm].

When the tooth length of the teeth 32 constituting the hub-side face spline 21 formed on the other axial end surface of the caulking portion 20 increases with the progress of the swing forging, the forming punch 39 descends and the gap 54 The axial dimension _L54 is reduced. Then, the tooth height of each tooth 32 becomes a desired size, and one end surface in the axial direction of the flange portion 45 of the molding punch 39 and the stepped surface portion 52 of the holding hole 51 abut (L ₅₄ = 0). In this state, the rocking forging is completed.

  In the case of this example, this roll 30a is supported so as to be able to rotate (rotate) about its own central axis β. Therefore, when the roll 30a is rotated about the central axis α of the hub body 8, the roll 30a is rotated based on the frictional engagement between the pressing surface 43 of the roll 30a and the other axial end surface of the forming punch 39. 30a rotates (rotates) about its own central axis β.

According to the manufacturing method of the wheel supporting rolling bearing unit 1 of the present example as described above, the manufacturing cost can be suppressed while ensuring the durability of the wheel supporting rolling bearing unit 1.
That is, in the case of this example, with the one axial end surface of the molding punch 39 opposed to the other axial end surface of the caulking portion 20, the other axial end surface of the molding punch 39 is connected to the roll 30a. While being pressed by the pressing surface 43, the roll 30 a is rotated around the central axis α of the hub body 8. As a result, the processing teeth 44, 44 formed on one axial end surface of the forming punch 39 are pressed against the other axial end surface of the caulking portion 20, so that the hub side face is pressed against the other axial end surface of the caulking portion 20. The spline 21 is formed. Here, the punch elements 46 and 46 constituting the forming punch 39 can only be displaced in the axial direction. Therefore, even if the other axial end surfaces of the punch elements 46 and 46 are pressed by the pressing surface 43 of the roll 30a while rotating the roll 30a around the central axis α of the hub body 8, The tooth surfaces of the processing teeth 44, 44 are not inclined with respect to the tooth surfaces of the teeth 32 constituting the hub-side face spline 21. Accordingly, it is possible to prevent the occurrence of local contact between the tooth surfaces of the processed teeth 44 and 44 and the axial end surfaces of the caulking portions 20 such that the tooth surfaces of the teeth 32 are locally plastically deformed. . Accordingly, the straightness of the cross-sectional shape of each tooth 32 can be improved, and the hub-side face spline 21 and the joint-side face spline 26 (see FIG. 9) formed on the constant velocity joint outer ring 2 are engaged with each other. Thus, the contact area between the tooth surfaces of the teeth 32 constituting the hub-side face spline 21 and the teeth constituting the joint-side face spline 26 can be sufficiently increased. As a result, it is possible to sufficiently ensure the durability of the meshing portion between the hub-side face spline 21 and the joint-side face spline 26, and hence the wheel support rolling bearing unit 1 as a whole.

  Further, since the inclination angle θ can be increased (this inclination angle θ can be 15 degrees or more), the pressing surface 43 of the roll 30a is directed toward the other end surface in the axial direction of the caulking portion 20 via the forming punch 39. The pressing force (pressing force) F can be prevented from becoming excessively large. As a result, it is possible to prevent the press device 36 from being increased in size, and to suppress an increase in the manufacturing cost of the wheel support rolling bearing unit 1. Particularly in the case of this example, of the circumferentially opposite side edges of the other axial end face of one punch element 46 of the punch elements 46, 46, the roll 30a centered on the central axis α A punch element that is present on the front side in the rotation direction of the roll 30a around the central axis α of the one punch element 46 in a state where the rear edge ζ in the rotation direction is pressed by the pressing surface 43 of the roll 30a. Out of both circumferential edges of the other end face in the axial direction of 46, the side edge η on the one punch element 46 side and the pressing face 43 of the roll 30a are in contact with each other. Accordingly, the pressing surface 43 of the roll 30a presses the rear side edge in the rotational direction of the roll 30a centered on the central axis α, out of both circumferential edges of the other axial end surface of the one punch element 46. When the roll 30a is rotated about the central axis α of the hub body 8 from the state where the roll 30a is rotated, the rotation of the roll 30a about the central axis α of the one punch element 46 and the hub body 8 is rotated. The punch element 46 existing on the front side in the direction starts to be pressed by the pressing surface 43 of the roll 30a. Thus, the pressing force by the roll 30a can be effectively used as a force for plastically deforming the other end surface in the axial direction of the caulking portion 20, and the force F can be kept small and required for processing. Time can be shortened.

  As is apparent from FIG. 11 described above, when the inclination angle θ of the central axis β of the roll 30a with respect to the central axis α of the hub body 8 exceeds 30 degrees, the pressing surface 43 of the roll 30a and the molding There is a possibility that the contact area with the other end surface in the axial direction of the punch 39 is reduced, the contact surface pressure between these two surfaces is excessively increased, and it is difficult to ensure the durability of the pressing surface 43 of the roll 30a. . Therefore, in the case of this example, the inclination angle θ is set to 30 degrees or less.

  Further, when carrying out the present invention, the outer peripheral surface of the molding punch is not provided with a flange portion protruding radially outward, and the outer peripheral surface of the molding punch is a single cylindrical surface whose outer diameter does not change in the axial direction. You can also do things. That is, it is assumed that this forming punch is a combination of a plurality of punch elements 46a each having a processing tooth 44 on one end face in the axial direction as shown in FIG. In this case, for example, the displacement amount of the roll 30a in the axial direction of the hub body 8 is detected, and when the displacement amount becomes the same as the tooth height of the teeth 32 constituting the hub-side face spline 21, Processing for forming the hub-side face spline 21 is completed.

When the manufacturing method of the rolling bearing unit of the present invention is carried out using the oscillating press device 36 shown in FIGS. 1 to 4 described above, both sides in the circumferential direction of the other axial end surface of one punch element 46. Of the edges, the rear edge in the rotation direction of the roll 30a around the central axis α of the hub body 8 is pressed by the pressing surface 43 of the roll 30a, and the one punch element 46 is Of the circumferentially opposite side edges of the other end face in the axial direction of the punch element 46 existing on the front side in the rotational direction (left side in FIG. 6) of the roll 30a around the central axis α of the hub body 8, the one punch A specific example of the pressing amount Δd _{max in} which the side edge on the element 46 side and the pressing surface 43 of the roll 30a come into contact with each other will be described.
First, the total number N of punch elements 46, 46 constituting the forming punch 39 is 31, and the inclination angle θ of the central axis β of the roll 30a with respect to the central axis α of the hub body 8 is 30 degrees. When the maximum diameter R of 43 is 24 [mm], the pressing amount Δd _max is 0.3 [mm]. Therefore, for example, when the rotation speed (rotational speed) of the roll 30a around the central axis α of the hub body 8 is set to 200 [rpm], the roll 30a is moved at a speed of 1 [mm / sec]. Press (displace) toward one side in the axial direction.
Alternatively, when the total number N is 31, the inclination angle θ is 15 degrees, and the maximum diameter R is 24 [mm], the pressing amount Δd _max is 0.13 [mm]. Therefore, for example, when the rotation speed of the roll 30a about the central axis α of the hub body 8 is set to 300 [rpm], the roll 30a is rotated at a speed of 0.65 [mm / sec]. Press toward one side (displace).

DESCRIPTION OF SYMBOLS 1 Wheel support bearing unit 2 Outer ring for constant velocity joint 3 Outer ring 4 Hub 5 Rolling element 6 Stationary side flange 7a, 7b Outer ring raceway 8 Hub body 9 Inner ring 10 Rotation side flange 11a, 11b Inner ring raceway 12 Small diameter step 13 Central hole 14 Small-diameter portion 15 Bolt 16 Hook portion 17 Male thread portion 18 Head portion 19 Cylindrical portion 20 Caulking portion 21 Hub side face spline 22 Mouse portion 23 End wall portion 24 Shaft portion 25 Screw hole 26 Joint side face spline 27 Inner ring for constant velocity joint 28 Ball 29a, 29b Cage 30, 30a Roll 31 Processing surface 32 Face spline teeth 33 Processing teeth 34 Recess 35 Step portion 36 Oscillating press device 37 Base 38 Holder 39 Molding punch 40 Punch lifting mechanism 41 Cylindrical portion 42 Holding recess 43 Pressing surface 44 Processing teeth 45 Flange 6 punch element 47 the element body 48 protruding portion 49 punch holding plate 50 the hydraulic cylinder 51 holding hole 52 step portion 53 closing plate 54 gap

Claims (5)

A hub body having an inner ring raceway on one side in the axial direction on an outer peripheral surface in the axial direction;
An inner ring raceway on the other side in the axial direction on the outer peripheral surface, and an inner ring fitted on a portion near the other axial end of the hub body,
The inner ring is fixed to the hub body by pressing the other end surface in the axial direction of the inner ring by a caulking part formed by plastically deforming a cylindrical part provided at the other axial end of the hub body radially outward. In order to construct a rolling bearing unit in which a hub side face spline that is an uneven portion in the circumferential direction is formed on the other end surface in the axial direction of the caulking portion,
The hub-side face spline is formed by combining a plurality of punch elements divided into a plurality in the circumferential direction, each of which can be displaced in the axial direction and blocked in the circumferential direction. With one axial end surface of the molding punch having the same number of teeth as the number of teeth as opposed to the other axial end surface of the caulking portion, the other axial end surface of the molding punch is set to the center of the hub body. The hub-side face spline is formed on the other end surface in the axial direction of the caulking portion by rotating the roll around the central axis of the hub body while pressing the pressing surface of the roll having a central axis inclined with respect to the axis. A method of manufacturing a rolling bearing unit.   The method for manufacturing a rolling bearing unit according to claim 1, wherein an inclination angle of the central axis of the roll with respect to the central axis of the hub body is 15 degrees or more.   3. The method for manufacturing a rolling bearing unit according to claim 1, wherein the forming punch is composed of the punch elements divided into the same number as the number of teeth of the processing teeth. 4.   Among the punch elements of one of the punch elements, of the circumferential opposite side edges of the other axial end surface, the rear edge in the rotation direction of the roll centered on the central axis of the hub body is pressed by the roll. Out of both circumferential edges of the other end surface in the axial direction of the punch element existing on the front side in the rotational direction of the roll centered on the central axis of the hub body of the one punch element in a state of being pressed by the surface The method for manufacturing a rolling bearing unit according to claim 3, wherein the side edge on the one punch element side is not pressed by the pressing surface of the roll.   A part of each punch element is held by each of the punch elements in a state where the tooth length of the hub side face spline formed on the other end surface in the axial direction of the caulking portion has a desired size. The manufacturing method of the rolling bearing unit according to claim 1, wherein each punch element is prevented from being further displaced in the other axial direction by abutting against a stepped surface portion provided in a portion to be performed.

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