JP2009248789A - Bearing device for wheel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing device for a wheel capable of efficiently transmitting torque between the hub spindle of a hub wheel and the outer ring of a constant velocity joint. <P>SOLUTION: The hub spindle 13 of the hub wheel 10 on which a wheel is mounted and the outer ring 60 of the constant velocity joint 50 are coupled capable of transmitting torque, and a rolling bearing 20 is mounted on the outer periphery of the hub spindle 13. An inner ring 21 of the rolling bearing 20 is fitted to the outer peripheral face of the hub spindle 13. At a shaft end of the hub spindle 13, an extension shaft part 17 extending further inward in the vehicle width direction than an end face of the inner ring 21 of the rolling bearing 20 is formed, and a male spline 18 is formed on the outer peripheral face of the extension shaft part 17. A cylinder part 62 that can be fitted with the extension shaft part 17 is formed on an end wall part 61 of the outer ring 60 of the constant velocity joint 50, and a female spline 63 fitted to the male spline 18 for transmitting torque between the hub spindle 13 and the outer ring 60 of the constant velocity joint 50 is formed on the inner peripheral face of the cylinder part 62. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a wheel bearing device in which a hub shaft of a hub wheel to which a wheel is attached and an outer ring of a constant velocity joint are connected so that torque can be transmitted, and a rolling bearing is assembled to the outer periphery of the hub shaft.

This type of wheel bearing device is disclosed in Patent Document 1, for example.
In the wheel bearing device disclosed in Patent Document 1, an inner ring of a rolling bearing is fitted to the outer peripheral surface of the hub shaft, and a shaft end portion of the hub shaft is caulked radially outward to form a caulking portion. As a result, an axial preload is applied to the inner ring of the rolling bearing.
In addition, a female spline is formed in the axial direction of the inner peripheral surface of the central hole of the hub shaft of the hub wheel, and a male spline corresponding to the female spline is formed in the outer peripheral surface axial direction of the central shaft protruding from the end surface of the outer ring of the constant velocity joint. A spline is formed.
Then, with the female spline of the hub shaft and the male spline of the center axis of the constant velocity joint being spline-fitted, the fastening nut is tightened to the male screw portion at the tip of the center shaft of the constant velocity joint, etc. The outer ring of the speed joint and the hub axle are fastened so as to be able to transmit torque.
JP 2002-70880 A

  By the way, in the wheel bearing device, in order to increase the torque transmission force due to the structure in which the female spline in the central hole of the hub shaft and the male spline of the central shaft of the constant velocity joint are spline-fitted to transmit torque. The outer diameter of the center shaft of the constant velocity joint and the diameter of the center hole of the hub shaft must be increased, which increases the overall outer diameter of the wheel bearing device, which leads to an increase in size and weight. It will be.

  In view of the above problems, an object of the present invention is to provide a wheel bearing device capable of efficiently transmitting torque between a hub shaft of a hub wheel and an outer ring of a constant velocity joint.

In order to achieve the above object, a wheel bearing device according to claim 1 of the present invention is configured such that a hub shaft of a hub wheel to which a wheel is attached and an outer ring of a constant velocity joint are connected so as to be able to transmit torque. A wheel bearing device in which a rolling bearing is assembled on the outer periphery,
An inner ring of the rolling bearing is fitted to the outer peripheral surface of the hub shaft,
An extension shaft portion extending inward in the vehicle width direction from the end surface of the inner ring of the rolling bearing is formed at the shaft end of the hub shaft, and a male spline is formed on the outer peripheral surface of the extension shaft portion,
A cylindrical portion that can be fitted to the extension shaft portion is formed on an end wall portion of the outer ring of the constant velocity joint, and an inner peripheral surface of the cylindrical portion is fitted to the male spline to A female spline for transmitting torque between the hub shaft and the outer ring of the constant velocity joint is formed.

According to the above configuration, torque transmission is achieved by spline fitting the male spline formed on the outer peripheral surface of the extension shaft portion of the hub shaft and the female spline formed on the inner peripheral surface of the cylindrical portion of the outer ring of the constant velocity joint. The outer diameter of the spline can be increased compared to the conventional spline fitting of the female spline in the center hole of the hub shaft and the male spline in the center shaft of the outer ring of the constant velocity joint. The transmission power can be increased.
In this manner, torque can be efficiently transmitted between the hub shaft and the outer ring of the constant velocity joint, so that an increase in the size and weight of the entire wheel bearing device can be suppressed.

The wheel bearing device according to claim 2 is the wheel bearing device according to claim 1,
A female thread corresponding to the fastening bolt is formed at the center of the end wall of the outer ring of the constant velocity joint,
The male screw of the fastening bolt is inserted from the outer side in the vehicle width direction of the center hole of the hub shaft and screwed into the female screw of the end wall portion, so that the end surface of the inner ring of the hub shaft and the outer ring of the constant velocity joint are cylindrical. The hub shaft and the outer ring of the constant velocity joint are fastened in a state where the front end surface of the portion is in contact.

According to the above configuration, by inserting the fastening bolt from the outer side in the vehicle width direction of the center hole of the hub shaft and screwing it into the end wall portion of the outer ring of the constant velocity joint, the end surface of the inner ring of the hub shaft and the cylinder of the outer ring of the constant velocity joint The shaft diameter of the fastening bolt is larger than the diameter of the central shaft of the outer ring of the conventional constant velocity joint. It is also possible to easily reduce the weight.
Further, the axial preload can be appropriately applied to the inner ring of the rolling bearing on the outer peripheral surface of the hub shaft by the tightening force of the fastening bolt.

  Next, the best mode for carrying out the present invention will be described with reference to examples.

Example 1
A first embodiment of the present invention will be described with reference to FIGS.
1 is a longitudinal sectional view showing a wheel bearing device according to Embodiment 1 of the present invention. FIG. 2 is an enlarged longitudinal sectional view showing a spline fitting portion between the extension shaft portion of the hub shaft and the cylindrical portion of the outer ring of the constant velocity joint. FIG. 3 is a longitudinal sectional view showing a state where the hub wheel and the constant velocity joint are separated.

As shown in FIG. 1, the wheel bearing device according to the first embodiment includes a hub wheel 10, a double row angular ball bearing 20 as a rolling bearing, a constant velocity joint 50, and a fastening bolt 70. It is configured.
The hub wheel 10 is integrally provided with a hub shaft 13 having a center hole 14 and a cylindrical shape, and a flange 11 formed on an outer peripheral surface near one end of the hub shaft 13. A plurality of hub bolts 12 for attaching a wheel (not shown) with a brake rotor (not shown) interposed therebetween are fixed to the flange 11 at a predetermined pitch and press-fitted.
A double-row angular ball bearing 20 including an outer ring 30, an inner ring 21, a plurality of balls 41 and 42 as rolling elements and cages 45 and 46 is assembled to the outer periphery of the hub shaft 13.

In the first embodiment, the hub shaft 13 is continuously formed with a large-diameter shaft portion 15 formed on the flange 11 side and a diameter that is appropriately smaller than the large-diameter shaft portion 15 and with the large-diameter shaft portion 15 and a stepped portion. The small-diameter shaft portion 16 is integrally provided. Of the raceway surfaces formed on the inner circumferential surface of the outer ring 30 of the angular ball bearing 20, a raceway surface 22 corresponding to one raceway surface 31 is formed on the outer circumferential surface of the large-diameter shaft portion 15.
A raceway surface 23 corresponding to the other raceway surface 32 of the outer ring 30 is formed on the outer circumference surface of the inner ring 21 that is press-fitted and fixed to the outer circumference surface of the small-diameter shaft portion 16 of the hub shaft 13.
A plurality of balls 41 and 42 and a plurality of these balls 41 and 42 are respectively provided between the raceway surfaces 31 and 32 of the outer ring 30 and the raceway surfaces 22 and 23 on the hub shaft 13 side. The holders 45 and 46 to be held are assembled.
In addition, a fixing flange 35 is integrally formed on the outer peripheral surface of the outer ring 30 to be attached to a vehicle body side member (knuckle or carrier) supported by a vehicle suspension device (not shown) with a bolt.

As shown in FIGS. 1 and 2, a cylindrical extension shaft portion 17 extending inward in the vehicle width direction from the end surface of the inner ring 21 of the angular ball bearing 20 is formed at the shaft end of the small diameter shaft portion 16 of the hub shaft 13. Has been. A male spline 18 is formed in the axial direction of the outer peripheral surface of the extension shaft portion 17.
In the first embodiment, the male spline 18 is formed from a part of the small diameter shaft portion 16 of the hub shaft 13 to the entire length of the extension shaft portion 17.
Further, in the range of the small-diameter shaft portion 16 and the male spline 18 of the hub shaft 13, a surface treatment processing portion 19 whose hardness is increased by quenching (heat treatment or the like) is provided (range indicated by a chain line in FIG. 2). .

As shown in FIGS. 1 and 2, the constant velocity joint 50 uses a known constant velocity joint called a Zepper type or a barfield type, and is integrally connected to one end of the drive shaft 51. An inner ring 52, an outer ring 60, a plurality of balls 53 disposed between the inner and outer rings 52, 60, and a cage 54 that holds the plurality of balls 53 are configured.
Further, a cylindrical tubular portion 62 that can be fitted onto the extension shaft portion 17 of the hub shaft 13 is integrally protruded from the end wall portion 61 of the outer ring 60 of the constant velocity joint 50. A female spline 63 is formed on the inner peripheral surface of the cylindrical portion 62 to fit the male spline 18 of the extension shaft portion 17 of the hub shaft 13 and transmit torque between the hub shaft 13 and the outer ring 60 of the constant velocity joint 50. ing.
Of the male and female splines 18, 63, one spline, for example, each spline tooth constituting the male spline 18 has a spiral shape with an appropriate lead angle set in the circumferential direction, and is axially It extends. Moreover, each spline tooth | gear which comprises the female spline 63 as the other spline is extended in parallel with the axial direction.

As shown in FIGS. 1 and 2, a female screw 65 corresponding to the male screw 73 of the fastening bolt 70 is formed at the center of the end wall 61 of the outer ring 60 of the constant velocity joint 50.
The fastening bolt 70 is inserted through a seated head 71 integrally having a seat having an appropriately larger diameter than the center hole 14 of the hub shaft 13 and a smaller diameter than the center hole 14 through the center hole 14 with an annular space therebetween. The shaft portion 72 is provided with a male screw 73 corresponding to the female screw 65 of the end wall portion 61 of the outer ring 60 of the constant velocity joint 50.
After the male spline 18 of the extension shaft portion 17 of the hub shaft 13 and the female spline 63 of the cylindrical portion 62 of the outer ring 60 of the constant velocity joint 50 are spline-fitted, the shaft portion 72 of the fastening bolt 70 is connected to the hub. The end of the inner ring 21 of the hub shaft 13 and the constant velocity joint 50 are inserted by inserting the male screw 73 into the female screw 65 of the end wall portion 61 with a required torque. The hub axle 13 and the outer ring 60 of the constant velocity joint 50 are fastened so as to be able to transmit torque in a state where the front end surface of the cylindrical portion 62 of the outer ring 60 is in contact.

The wheel bearing device according to the first embodiment is configured.
Accordingly, the center of the conventional hub shaft is transmitted in the torque transmission by the spline fitting between the male spline 18 of the extension shaft portion 17 of the hub shaft 13 and the female spline 63 of the cylindrical portion 62 of the outer ring 60 of the constant velocity joint 50. The outer diameter of the male spline 18 can be increased and the hub shaft 13 can be increased by increasing the torque transmission force as compared with the spline fitting of the female spline of the hole and the male spline of the center shaft of the outer ring of the constant velocity joint. And the outer ring 60 of the constant velocity joint 50 can be efficiently transmitted. For this reason, the enlargement and weight increase of the whole wheel bearing apparatus can be suppressed.

  Further, in the first embodiment, since the male spline 18 of the hub shaft 13 is provided with the surface treatment processing portion 19 to increase the hardness, the fitting length of both the male and female splines 18 and 63 is subjected to the surface treatment processing. Necessary and sufficient torque transmission force can be obtained even if the portion 19 is not provided. For this reason, the fitting length of both the male and female splines 18 and 63 can be shortened to suppress an increase in the axial length of the entire wheel bearing device.

In the first embodiment, the shaft portion 72 of the fastening bolt 70 has a smaller diameter than the center hole 14 of the hub shaft 13 and is inserted through the center hole 14 with an annular space therebetween. The weight can be easily reduced as compared with the case where the center axis of the outer ring of the constant velocity joint is spline-fitted so that torque can be transmitted. That is, the weight can be reduced by an amount corresponding to the annular space between the shaft portion 72 of the fastening bolt 70 and the center hole 14 of the hub shaft 13.
Further, the tightening force of the fastening bolt 70 can appropriately apply a desired axial preload to the inner ring 21 of the hub shaft 13 and facilitate the management of the preload of the inner ring 21.

(Example 2)
Next, a second embodiment of the present invention will be described with reference to FIG.
FIG. 4 is an enlarged longitudinal sectional view showing a portion of an end wall portion of an outer ring of a constant velocity joint in a wheel bearing device according to Embodiment 2 of the present invention.

As shown in FIG. 4, in the second embodiment, the outer ring 160 of the constant velocity joint 150 and the end wall portion 161 are configured by separate members, and the end wall portion 161 is formed by pressing a steel plate. An outer diameter cylindrical portion 161a that is press-fitted and fixed to the cylindrical portion 162 at the end of the outer ring 160, an inner diameter cylindrical portion 161b that has a female screw 165 into which the male screw 73 of the fastening bolt 70 is screwed, and an inner and outer diameter cylindrical portion. It has integrally with a flange portion 161c that connects 161a and 161b.
On the other hand, at one end portion of the outer ring 160 of the constant velocity joint 150, a cylindrical tubular portion 162 is integrally formed in a penetrating state. A press-fit hole 164 and a female spline 163 are formed adjacent to each other on the same center line on the inner peripheral surface of the cylindrical portion 162.
And the end wall part 161 is press-fitted and fixed to the press-fitting hole 164 of the cylindrical part 162 in the outer diameter cylindrical part 161a.
Since the other structure of this Example 2 is comprised similarly to Example 1, the same code | symbol is attached | subjected with respect to the same component, and the description is abbreviate | omitted.

Therefore, the wheel bearing device according to the second embodiment also has the same effects as the first embodiment.
In particular, in the second embodiment, the end wall portion 161 is formed by breathing and is press-fitted into the cylindrical portion 162 of the outer ring 160 of the constant velocity joint 150, so that the end wall portion 161 is thinner than the first embodiment. Thus, the weight can be easily reduced.
Moreover, the processing of the female spline 163 with respect to the inner peripheral surface of the cylindrical portion 162 of the outer ring 160 of the constant velocity joint 150 can be easily processed in a state before the end wall portion 161 is press-fitted. That is, in the first embodiment, since the cylindrical portion 62 is closed by the end wall portion 61 integral with the outer ring 60, it is difficult to form the female spline 63 by broaching, but in this second embodiment, The female spline 163 can be easily formed on the inner peripheral surface of the cylindrical portion 162 of the outer ring 160 of the constant velocity joint 150 by broaching.

The present invention is not limited to the first and second embodiments.
For example, in the first and second embodiments, the shaft portion 72 of the fastening bolt 70 is inserted from the outer side in the vehicle width direction of the center hole 14 of the hub shaft 13 and screwed into the end wall portion 61 of the outer ring 60 of the constant velocity joint 50. The connecting shaft (including the center shaft and bolts) protrudes from the end wall portion of the outer ring of the constant velocity joint, and after passing through the center hole of the hub shaft, this connecting shaft is inserted into the end of the connecting shaft. The present invention can also be implemented in a configuration in which a fastening nut is fastened to the male screw portion and the hub shaft and the outer ring of the constant velocity joint are fastened so as to transmit torque.
Moreover, in the said Example 1 and 2, although the case where the double row angular ball bearing was employ | adopted as a rolling bearing was illustrated, this invention can be implemented even if it uses a double row tapered roller bearing other than an angular ball bearing. It is.

It is a longitudinal cross-sectional view which shows the wheel bearing apparatus which concerns on Example 1 of this invention. Similarly, it is a longitudinal sectional view showing an enlarged spline fitting portion between the extension shaft portion of the hub shaft and the cylindrical portion of the outer ring of the constant velocity joint. It is a longitudinal section showing the state where a hub wheel and a constant velocity joint were separated similarly. It is a longitudinal cross-sectional view which expands and shows the part of the end wall part of the outer ring | wheel of the constant velocity joint in the wheel bearing apparatus which concerns on Example 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 110 Hub wheel 11 Flange 13 Hub shaft 14 Center hole 17 Extension shaft part 18 Male spline 20 Angular contact ball bearing (rolling bearing)
50, 150 Constant velocity joint 60, 160 Outer ring 62, 162 Cylindrical part 63, 163 Female spline 61, 161 End wall part 70 Fastening bolt

Claims (2)

A wheel bearing device in which a hub shaft of a hub wheel to which a wheel is attached and an outer ring of a constant velocity joint are connected so as to be able to transmit torque, and a rolling bearing is assembled to the outer periphery of the hub shaft,
An inner ring of the rolling bearing is fitted to the outer peripheral surface of the hub shaft,
An extension shaft portion extending inward in the vehicle width direction from the end surface of the inner ring of the rolling bearing is formed at the shaft end of the hub shaft, and a male spline is formed on the outer peripheral surface of the extension shaft portion,
A cylindrical portion that can be fitted to the extension shaft portion is formed on an end wall portion of the outer ring of the constant velocity joint, and an inner peripheral surface of the cylindrical portion is fitted to the male spline to A wheel bearing device, wherein a female spline for transmitting torque between a hub shaft and an outer ring of the constant velocity joint is formed. The wheel bearing device according to claim 1,
A female thread corresponding to the fastening bolt is formed at the center of the end wall of the outer ring of the constant velocity joint,
The male screw of the fastening bolt is inserted from the outer side in the vehicle width direction of the center hole of the hub shaft and screwed into the female screw of the end wall portion, so that the end surface of the inner ring of the hub shaft and the outer ring of the constant velocity joint are cylindrical. A wheel bearing device characterized in that the hub shaft and the outer ring of the constant velocity joint are fastened in a state where the tip end surface of the part abuts.

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