JP2009287594A - Rolling bearing device and its manufacturing method - Google Patents

Abstract

The present invention provides a rolling bearing device capable of reducing the weight and ensuring the strength.
A hub unit (rolling bearing device) includes an outer ring fixed to a vehicle body side, a hub wheel 3 (inner ring) fixed to a brake disc rotor or the like (wheel side) and arranged coaxially with the outer ring, and an outer ring. Rolling elements arranged in the circumferential direction between the inner ring 3 and the inner ring 3. The hub wheel 3 is formed with a fiber flow F in which the texture is oriented spirally around the axis O by forging. The fiber flow F is formed by a forward extrusion process in which the material is flowed in the punching direction to reduce the cross-sectional area of the material B and at the same time, a twisting force about the axis O is applied to the material B.
[Selection] Figure 3

Description

  The present invention relates to a rolling bearing device and a manufacturing method thereof, and more particularly, to a rolling bearing device that supports a wheel of an automobile and a manufacturing method thereof.

  This type of rolling bearing device is increasingly required to have improved strength (rigidity) so that it can withstand, for example, high lateral acceleration generated during turning, for example, due to recent improvements in vehicle running stability. On the other hand, there is no limit to the reduction in size and weight. In order to achieve these conflicting demands, for example, in Patent Documents 1 and 2 below, the angle of the fiber flow with respect to the raceway surface of the outer member (outer ring) or hub ring (inner ring) of the rolling bearing device is a predetermined angle or less. Thus, a technique for forming an outer member or a hub wheel by forging is disclosed.

JP 2005-83513 A JP 2007-147079 A

  However, in the rolling bearing devices described in Patent Documents 1 and 2, although it is possible to improve the rolling life of the raceway surface of the outer member or the hub ring, the fiber flow obtained by forging is the outer member or Since it is oriented so that it is located on the cut surface including the axis of the hub wheel (it looks straight when viewed from the front), the overall strength of the outer member or hub wheel cannot be improved.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a rolling bearing device capable of improving the overall strength of an outer ring (for example, an outer member) or an inner ring (for example, a hub ring) and its manufacture. It is to provide a method.

Means for Solving the Problems and Effects of the Invention

  In order to solve the above problems, the present invention is arranged in the circumferential direction between an outer ring fixed to the vehicle body side, an inner ring fixed to the wheel side and disposed coaxially with the outer ring, and the outer ring and the inner ring. In the rolling bearing device including the rolling element, the outer ring or the inner ring is formed with a fiber flow in which the structure is spirally oriented around the axis of the outer ring or the inner ring by forging.

  In the rolling bearing device of the present invention, the outer ring or the inner ring is formed with a fiber flow in which the structure is oriented spirally around the axis of the outer ring or the inner ring by forging. For this reason, the torsional rigidity around the axis of the outer ring or inner ring can be made higher than that of the prior art, and the overall strength of the outer ring or inner ring can be improved.

  The rolling bearing device manufacturing method of the present invention includes an outer ring fixed to the vehicle body side, an inner ring fixed to the wheel side and arranged coaxially with the outer ring, and a circumferential arrangement between the outer ring and the inner ring. In the manufacturing method of the rolling bearing device provided with the rolling elements, a forging process is provided in which a material constituting the outer ring or the inner ring and a punch for pressurizing the material are relatively rotated about the axis. In this case, the forging process is preferably a forward extrusion process in which, for example, the material is caused to flow in the punching direction to reduce the cross-sectional area of the material, and at the same time, a twisting force about the axis is applied to the material.

  In the manufacturing method of the rolling bearing device of the present invention, the material constituting the outer ring or the inner ring and the punch for pressurizing the material are relatively rotated around the axis. For this reason, it is possible to orient the fiber flow spirally around the axis. In particular, when it is configured to apply a twisting force around the axis to the material during the forward extrusion process, a fiber flow that twists toward the rear of the free forging side with the front of the material having a large restraining force as the base end. Can be formed satisfactorily.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an arrangement configuration diagram of a hub unit 1 employing the rolling bearing device of the present invention, and FIG. 2 is a longitudinal sectional view of the hub unit 1 shown in FIG. In the following description, the vehicle inner side indicates the left side in FIG. 2, and the vehicle outer side indicates the right side in FIG.

  The hub unit 1 is, for example, one on the rear wheel side (driven wheel side) of the front wheel drive vehicle, and has a double-row outward angular ball bearing structure. Specifically, the hub unit 1 includes an outer ring 2 fixed to the hub knuckle 10 on the vehicle body BD side, a tire wheel (not shown) on the wheel side, and a brake disc rotor arranged coaxially with the axis O of the outer ring 2. The hub wheel 3 (inner ring) fixed to 20, the inner ring member 4 fitted to the outer peripheral surface of the vehicle inner side end of the hub wheel 3, and the hub wheel 3 or the inner ring member 4 in the circumferential direction. And a plurality of rolling elements 5 to be arranged.

  The outer ring 2 has a cylindrical main body portion 2a extending in the axial direction, a cylindrical portion 2b formed to protrude in the axial direction on the vehicle inner side of the main body portion 2a, and a radial projection on the vehicle inner side of the main body portion 2a. And a hub mounting flange 2c formed. A raceway surface 2a1 for the rolling element 5 disposed on the vehicle outer side and a raceway surface 2a2 for the rolling element 5 disposed on the vehicle inner side are formed on the inner peripheral surface of the main body 2a.

  The cylindrical portion 2 b is inserted inside the outer ring accommodation hole 11 of the hub knuckle 10. The hub attachment flange 2c abuts on the peripheral edge of the outer ring accommodation hole 11 of the hub knuckle 10 and restricts the movement of the main body 2a relative to the hub knuckle 10 in the axial direction. The hub mounting flange 2c is integrally formed with an outer ring fastening portion 2d having a plurality of bolt insertion holes 2d1, and a bolt (not shown) is screwed to the bolt insertion holes 2d1 so that the outer ring 2 is connected to the hub. It is attached to the knuckle 10.

  The hub wheel 3 includes a stepped shaft portion 3a that extends in the axial direction and protrudes from the outer ring 2 on the vehicle outer side, and a wheel mounting flange 3b that is formed to protrude in the radial direction on the vehicle outer side of the shaft portion 3a. And a cylindrical in-row portion 3c that is formed to protrude in the axial direction on the vehicle outer side of the shaft portion 3a. A raceway surface 3a1 is formed on the outer peripheral surface of the main body 3a so as to correspond to the raceway surface 2a1 of the outer ring 2. A raceway surface 4 a corresponding to the raceway surface 2 a 2 of the outer ring 2 is formed on the outer peripheral surface of the inner ring member 4.

  A through hole 3a2 having a predetermined size is formed coaxially with the axis O in the shaft 3a, and a reinforcing material 31 is inserted into the through hole 3a2. The reinforcing material 31 is made of a metal material such as aluminum or copper having a small specific gravity and a large linear expansion coefficient (linear expansion coefficient) as compared with carbon steel such as S55C forming the hub wheel 3.

  The wheel mounting flange 3b is formed with a plurality of bolt holes 3b1 used for mounting to the tire wheel and the brake disc rotor 20, and the bolts 6 are press-fitted into the bolt insertion holes 3b1, thereby the tire A wheel and brake disc rotor 20 is mounted on the wheel mounting flange 3b. The in-row part 3 c is inserted inside the inner ring accommodation hole 21 of the brake disc rotor 20.

  An annular space for disposing the rolling elements 5 is formed between the outer ring 2 and the hub wheel 3, and the annular spaces are ring-shaped seal members 7 and 8 on the vehicle inner side and the vehicle outer side. Thus, the outer ring 2 and the hub wheel 3 are sealed in a state that allows relative rotation.

  The hub wheel 3 of this embodiment is formed by cold die forging. As shown in FIGS. 3A and 3B, the hub wheel 3 is formed with a fiber flow F (fibrous structure, forging line) in which the structure is spirally oriented around the axis O by forging. . Specifically, the hub wheel 3 is formed in a predetermined outer shape through a forward extrusion process, an upsetting process (heading), a backward extrusion process, and the like.

  In the forward extrusion process, the hollow cylindrical material B is caused to flow in the direction in which the punch 41 advances, and the cross-sectional area of the material B is reduced by a predetermined amount along the inner peripheral surface of the die 42 (see FIG. 4A). FIG. 4A schematically shows the processed material B. However, the rough extrusion dimension obtained by adding a turning finishing allowance to the raceway surface 3a1 by this forward extrusion process. (The same is true for FIG. 4B). In the upsetting process, a head B1 which is the original shape of the wheel mounting flange 3b is formed (see FIG. 4B). Thereafter, the material B obtained in the upsetting process is transferred to another mold, and in the backward extrusion process, the wheel mounting flange 3b and the in-row part 3c are formed from the head B1 (see FIG. 3).

  By the way, in this embodiment, a twisting force around the axis O is applied to the material B in the forward extrusion process. That is, the punch 41 includes a ball screw portion 41a, and the ball screw portion 41a is rotatably supported by the ball screw nut 41b. Then, the ball screw nut 41b is pressurized toward the die 42 by the drive source D1, and the punch 41 is rotationally driven around the axis O by the drive source D2 so as to push and rotate the material B by a predetermined rotation amount. It has become.

  As a result, the material B is twisted with the rotation of the punch 41 with the front portion having a large frictional resistance against the die 42 as the base end, and the fiber flow F spirals around the axis O. It becomes oriented in the shape. The twist angle α of the fiber flow F formed with the rotation of the punch 41 is preferably set to 45 ° or less. This is because if the angle exceeds 45 °, the shaft rigidity against the bending moment decreases, and it is necessary to ensure the shaft rigidity.

  As is clear from the above description, in this embodiment, the fiber flow F in which the structure is oriented spirally around the axis O of the hub wheel 3 is formed by forging. As a result, as shown in FIG. 6 (corresponding to FIG. 3B), the torsional rigidity around the axis O of the hub wheel 3 is higher than that of the hub wheel 300 in which the fiber flow F1 is formed by forging according to the prior art. The height of the hub wheel 3 can be increased and the overall strength of the hub wheel 3 can be improved.

  In the above embodiment, the present invention is applied to the hub wheel 3 having the through hole 3a2. However, the present invention is not limited to this, and the present invention may be applied to a solid hub wheel 103 as shown in FIG. Good. Since the other configuration is the same as that of the above-described embodiment, portions having the same functions as those of the above-described embodiment are denoted by the same reference numerals and description thereof is omitted.

  In the above embodiment, the present invention is applied to the hub wheel 3 as the inner ring. However, the present invention can also be applied to the outer ring 2 in the same manner as the hub wheel 3.

  Further, in the above embodiment, the spiral fiber flow F having the front end of the material B as the base end is formed by rotating the punch 41 around the axis O with respect to the material B. A pedestal that can rotate around the axis O with respect to the punch 41 may be incorporated on the side 42, and the pedestal may be rotated when the material B is pressed by the punch 41.

The arrangement block diagram of the hub unit which concerns on one Embodiment of the rolling bearing apparatus of this invention. The longitudinal cross-sectional view of the hub unit of FIG. (A) is a longitudinal cross-sectional view which shows the fiber flow of the hub wheel of FIG. (B) is AA sectional drawing of (a). (A) is explanatory drawing which shows a front extrusion process among the forging processes which concern on one Embodiment of the manufacturing method of the rolling bearing apparatus in this invention. (B) is explanatory drawing which shows the upsetting process performed after (a). The longitudinal cross-sectional view of the hub wheel which concerns on the deformation | transformation embodiment of the rolling bearing apparatus of this invention. FIG. 4 is a cross-sectional view showing a fiber flow of a hub wheel by forging according to the prior art, corresponding to FIG.

Explanation of symbols

BD Car body 1 Hub unit (rolling bearing device)
2 Outer ring 3,103 Hub wheel (inner ring)
3a Shaft portion 3a2 Through hole 3b Wheel mounting flange 3c Inrow portion 5 Rolling element 10 Hub knuckle 20 Brake disc rotor 31 Reinforcement material 41 Punch 41a Ball screw portion 41b Ball screw nut 42 Die B Material F Fiber flow

Claims (3)

A rolling bearing comprising an outer ring fixed to the vehicle body side, an inner ring fixed to the wheel side and disposed coaxially with the outer ring, and a rolling element disposed circumferentially between the outer ring and the inner ring. In the device
A rolling bearing device in which the outer ring or the inner ring is formed with a fiber flow in which a structure is spirally formed around an axis of the outer ring or the inner ring by forging. A rolling bearing comprising an outer ring fixed to the vehicle body side, an inner ring fixed to the wheel side and disposed coaxially with the outer ring, and a rolling element disposed circumferentially between the outer ring and the inner ring. In the device manufacturing method,
A method for manufacturing a rolling bearing device, comprising: a forging step in which a material constituting the outer ring or the inner ring and a punch for pressurizing the material are relatively rotated about an axis.   The forging step is a forward extrusion step of applying a twisting force about an axis to the material while simultaneously reducing the cross-sectional area of the material by flowing the material in a direction in which the punch proceeds. A method for manufacturing the rolling bearing device according to claim.

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