JPH10181304A - Hub unit bearings for wheels - Google Patents

Abstract

[PROBLEMS] To provide a hub unit bearing for a wheel which has a long life and high rigidity, and can realize this without increasing the weight or increasing the cost. A hub unit bearing includes a hub shaft and a wheel spigot portion. The hub shaft 16 has a bottom wall portion 18 formed integrally and a bottomed cylindrical shape as a whole, and a support portion 30 is formed integrally with the wheel spigot portion 28. Here, the bottom wall portion 18 and the support portion 30 are provided at positions where the input vector line P of the load from the ball 38 intersects the cylindrical main body portion 16A of the hub shaft 16. Thereby, even if the hub shaft 16 is formed in a cylindrical shape, rigidity and strength can be ensured, and both high life and rigidity, which are mutually exclusive, and weight reduction and low cost can be satisfied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a hub unit bearing for a wheel of a vehicle such as an automobile.

[0002]

2. Description of the Related Art In bearings for supporting wheels of vehicles such as automobiles, tapered roller bearings and deep groove ball bearings are commonly used.
Double-row angular contact ball bearings have been used in place of the conventional structure using individual pieces, but in recent years hub unit bearings have been widely used.

FIG. 3 is a cross-sectional view of a hub unit bearing 50 which has been widely used in recent years. The hub unit bearing 50 includes an outer ring 52 attached to the vehicle body, a double-row ball 54, an outer inner ring integrally provided, and a hub shaft 58 press-fitted into the inner ring 56.
A disk wheel (not shown) is directly attached to the disk.

[0004] Such a hub unit bearing 50 has the advantages that the structure is simple, the number of parts is small, the size and weight can be reduced, and the assembling is simple and the assembling workability is improved.

Incidentally, such a hub unit bearing 5
0, it is necessary to ensure the durability and life of the bearing. Particularly in recent years in which the weight of the vehicle tends to increase, it is desired to greatly improve the durability and life of the hub unit bearing 50. I have.

Here, in order to improve the durability and life of the hub unit bearing 50, the diameter of the ball 54 must be increased.
PCD expansion of ball 54, span expansion between balls 54,
And so on. In this case, in consideration of an increase in the mass of the hub unit bearing 50 and an increase in cost, it is generally practiced to increase the diameter of the ball 54 in practice.

However, in order to cope with such an increase in the diameter of the ball 54, it is indispensable to reduce the sectional shape of the hub shaft 58 or to increase the diameter of the outer ring 52. Therefore, when the cross-sectional shape of the hub shaft 58 is reduced, rigidity and strength are reduced. When the diameter of the outer ring 52 is increased, the mass increases and the cost increases. I will.

On the other hand, in the countermeasure method of enlarging the PCD of the ball 54, although the rigidity and strength can be improved, the mass of the hub unit bearing 50 is greatly increased as a whole and the cost is increased.

In the countermeasure method of increasing the span between the balls 54, similarly, the mass of the hub unit bearing 50 is increased as a whole to increase the cost, and since the hub unit bearing 50 is elongated in the axial direction, the bending amount is increased. (Reduction in rigidity).

As described above, in the conventional measures for greatly improving the durability and life of the bearing, a long life and high rigidity are required.
Weight reduction and low cost are mutually exclusive, and none of these measures can satisfy both.

[0011]

SUMMARY OF THE INVENTION In view of the above facts, the present invention provides a hub unit bearing for a wheel which has a long service life and high rigidity and can realize this without increasing the weight or increasing the cost. Is the purpose.

[0012]

According to a first aspect of the present invention, there is provided a hub unit bearing for a wheel, wherein an outer ring attached to a vehicle body and an outer inner ring are integrally provided, and a hub shaft to which a disk wheel is attached; An inner-side inner ring fixed to a shaft, between the outer ring and the hub shaft, and a double-row ball held rotatably by a retainer between the outer ring and the inner-side inner ring,
A hub unit bearing for a wheel, wherein the hub shaft is formed in a hollow cylindrical shape, and the hub is located at a position where an input vector line of a load from the double rows of balls intersects a cylindrical main body portion of the hub shaft. It is characterized in that a pair of disk-shaped rib portions continuous with the cylindrical main body portion of the shaft are provided.

In the hub unit bearing for a wheel according to the first aspect, since the hub shaft is formed in a hollow cylindrical shape, the mass is greatly reduced. A pair of rib portions are formed on the hub shaft at positions where the input vector line of the load from the double rows of balls intersects with the cylindrical main body of the hub shaft. Therefore, input loads from multiple rows of balls are received by these rib portions, and rigidity and strength are secured.

As described above, the hub unit bearing for a wheel according to the first aspect can satisfy both high service life and high rigidity, which are mutually exclusive, and weight reduction and low cost. Therefore, if the mass is the same, the PCD of the ball can be greatly expanded (without increasing the mass), and the rigidity and strength can be further improved.
Further, since the hollow cylindrical hub shaft has a substantially uniform thickness, the hub shaft can be manufactured from a disk-shaped plate material, and the productivity is also improved.

A wheel hub unit bearing according to a second aspect of the present invention is the wheel hub unit bearing according to the first aspect, wherein a disk portion of the pair of rib portions located outside in the wheel width direction is formed by a disk wheel. It is characterized in that it is integral with the wheel spigot portion to be engaged and separate from the hub shaft.

In the hub unit bearing for a wheel according to the second aspect, the wheel spigot portion provided integrally with the rib portion located on the outer side in the wheel width direction is formed separately from the hub shaft. Surface treatment for preventing sticking to the disk wheel can be performed separately and independently from the processing of the hub unit bearing (in other words, there is no need to perform unnecessary surface treatment on the hub shaft). , Increasing productivity.

A wheel hub unit bearing according to a third aspect of the present invention is the wheel hub unit bearing according to the first or second aspect, wherein the outer end in the wheel width direction of the inner side inner ring is formed by the pair of ribs. The rib portion is provided at a predetermined distance outward from the rib portion located inward in the wheel width direction with respect to the rib portion located inward in the wheel width direction.

In the hub unit bearing for a wheel according to the third aspect, stress concentration does not occur at the outer end portion in the wheel width direction of the inner ring on the inner side (corresponding to the cylindrical main body portion of the hub shaft), which is more effective. It is a target.

According to a fourth aspect of the present invention, in the wheel hub unit bearing according to the first, second or third aspect, the inner side inner ring is press-fitted into the hub shaft. It is characterized by being fixed by caulking.

In the wheel hub unit bearing according to the fourth aspect, when the rigidity and strength are further improved by enlarging the PCD of the ball, the required surface pressure of the inner side inner ring (ball) is reduced. Can be fixed. Therefore, the inner side inner ring can be easily fixed, and the reliability is also improved.

[0021]

FIG. 1 is a sectional view showing the structure of a hub unit bearing 10 for a wheel according to an embodiment of the present invention. FIG. 2 shows the entire configuration of a wheel axle portion to which the hub unit bearing 10 is applied.

The hub unit bearing 10 has an outer ring 12. The outer ring 12 is attached to a steering knuckle 14 of the vehicle body. A hub shaft 16 is provided radially inside the outer ring 12. The hub shaft 16 has a hollow cylindrical shape, and has an outer side inner ring portion integrally provided.
A bottom portion 18 as a rib portion is integrally formed. On the other hand, a flange portion 20 is formed integrally with an end of the hub shaft 16 in the wheel outer direction. This flange 2
At 0, the brake drum 22 and the disc wheel 24 are fixed by a plurality of bolts 26.

A wheel spigot portion 28 is fixed to an end of the hub shaft 16 in the wheel outer direction. The wheel spigot portion 28 includes a support portion 3 as a rib portion.
0 is formed on the inner peripheral surface of the hub shaft 16 and is integrally fixed to the inner peripheral surface of the hub shaft 16. In this case, press-fitting, welding, or the like can be applied as a method of fixing the wheel spigot portion 28.

An inner inner ring 32 is fixed to the outer periphery of the hub shaft 16 at the inner end in the wheel direction. The inner side inner ring 32 is press-fitted into the hub shaft 16 and fixed by caulking by a caulking portion 34.

Further, between the outer race 12 and the hub shaft 16, and between the outer race and the inner inner race 32, two rows of balls 38 are held by a retainer 36 so as to freely roll.

Here, the hub unit bearing 1 having the above-described structure is used.
0, the bottom portion 18 as a rib portion is
8 is provided at a position where the input vector line P of the load from 8 intersects with the cylindrical main body portion 16A of the hub shaft 16. Similarly, the support portion 30 of the wheel spigot portion 28 is also provided at a position where the input vector line P of the load from the ball 38 intersects with the cylindrical main body portion 16A of the hub shaft 16.

Further, the outer end of the inner side inner race 32 in the wheel width direction is provided to be offset by a predetermined distance .sigma.

Next, the operation of the present embodiment will be described. In the hub unit bearing 10 for a wheel configured as described above, the hub shaft 16 is formed in a hollow cylindrical shape, so that the mass is significantly reduced. The bottom shaft portion 18 and the support portion 30 (a pair of ribs) are provided on the hub shaft 16 at positions where the input vector line P of the load from the two rows of balls 38 intersects the cylindrical main body portion 16A of the hub shaft 16. Part) is formed. Therefore, the input load from the double rows of balls 38 is received by the bottom wall portion 18 and the support portion 30, and rigidity and strength are secured.

As described above, in the hub unit bearing 10,
It is possible to satisfy both high service life and high rigidity, which are mutually exclusive, as well as weight reduction and low cost. Therefore, if the mass is the same (without increasing the mass), the ball 3
8 can be greatly expanded, and the rigidity and strength can be further improved. Further, since the thickness of the hollow cylindrical hub shaft 16 is substantially uniform,
The hub shaft 16 can be manufactured from a disk-shaped plate, and productivity is also improved.

In the hub unit bearing 10, the wheel spigot portion 28 integrally provided with the support portion 30 as a rib portion located on the outer side in the wheel width direction is formed by the hub shaft 1.
6 and separate from the hub unit bearing 10 (hub shaft 16).
(In other words, there is no need to perform unnecessary surface treatment on the hub shaft 16), and the productivity is improved.

Further, in the hub unit bearing 10, the outer end in the wheel width direction of the inner side inner ring 32 is connected to the hub shaft 1.
6 is offset from the bottom wall portion 18 of the inner side 32 in the wheel width direction by a predetermined distance σ to the outside in the wheel width direction. There is no stress concentration on the main body portion 16A), which is more effective.

Further, in the hub unit bearing 10,
When the rigidity and strength are further improved by enlarging the PCD of the ball 38, the required surface pressure of the inner side inner ring 32 (the ball 38) is reduced.
4 enables swaging. For this reason, the inner side inner ring 32 can be easily fixed, and the reliability is also improved.

[0033]

As described above, the hub unit bearing for a wheel according to the present invention has a long life and a high rigidity, and has an excellent effect that it can be realized without increasing the weight and the cost. Have.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a configuration of a wheel hub unit bearing according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing an overall configuration of a wheel axle portion to which the wheel hub unit bearing according to the embodiment of the present invention is applied.

FIG. 3 is a cross-sectional view illustrating a configuration of a conventional wheel hub unit bearing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Hub unit bearing 12 Outer ring 16 Hub shaft 16A Cylindrical main body part 18 Bottom wall part (rib part) 20 Flange part 24 Disk wheel 28 Wheel spigot part 30 Support part (rib part) 32 Inner side inner ring 34 Caulking part 36 Cage 38 ball

Claims (4)

[Claims] 1. An outer ring attached to a vehicle body, an outer inner ring is integrally provided, and a hub shaft to which a disk wheel is attached; an inner inner ring fixed to the hub shaft; and between the outer ring and the hub shaft. And a double-row ball rotatably held by a retainer between the outer ring and the inner inner ring, wherein the hub shaft is formed into a hollow cylindrical shape. A pair of disk-shaped rib portions continuous with the cylindrical main body portion of the hub shaft are provided at positions where input vector lines of loads from the double-row balls intersect with the cylindrical main body portion of the hub shaft. A hub unit bearing for a wheel, characterized in that: 2. A wheel part of the pair of rib parts which is located outside in the wheel width direction is integrated with a wheel spigot part with which a disk wheel engages and is separate from the hub shaft. Item 2. A hub unit bearing for a wheel according to item 1. 3. An outer end in the wheel width direction of the inner side inner ring is offset by a predetermined distance to the outside in the wheel width direction with respect to a rib portion of the pair of rib portions located inside in the wheel width direction. The wheel hub unit bearing according to claim 1 or 2, wherein: 4. The hub unit bearing for a wheel according to claim 1, wherein the inner side inner ring is press-fitted into the hub shaft and fixed by caulking.