JP2000170756A - Shell type needle-shaped roller bearing for universal joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To try to much narrow the radial gap of a shell type needle-shaped roller bearing. SOLUTION: A plurality of needle-shaped rollers 10 are provided in an outer race 1 formed out of a press molding product made out of a thin metal sheet with a bottom 3 provided while being laid along the orbital surface of the inner circumference of a cylindrical part 2 so as to be freely rolled. At least, one needle shaped roller 10a out of the plurality of the needle shape rollers 10, is made an over-sized one larger than the maximum size variation per unit container of the remaining needle shaped rollers 10, the insertion of the aforesaid over-sized needle shaped roller 10a into a needle shaped roller bearing by means of a trunnion, thereby allows the outer race to be pressed in the direction of a major diameter so as to be deformed into an elliptic shape for thereby narrowing each radial gap between the needle shaped roller bearing and the trunnion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a needle roller bearing incorporated in a universal joint.

[0002]

2. Description of the Related Art In a steering apparatus for an automobile, in which a steering wheel is steered by rotation of a steering wheel, a steering shaft for transmitting the rotation of the steering wheel to a steering gear box is formed by two relatively angled axes. 2. Description of the Related Art There has been known an art in which a universal joint is used to transmit rotational torque between two axes.

FIGS. 3 (I) and 3 (II) show an example of a universal joint used in the steering device. The universal joint includes a fork 2 provided on each of a pair of yokes 20.
1 and a spider 23 is formed in each bearing hole 22.
Is inserted into each trunnion 2
4 is a shell-shaped needle roller bearing 30 press-fitted into a bearing hole 22.
And rotatably supported.

Here, the needle needle roller bearing 30 has a bottom 31b at one end of a cylindrical portion 31a which is press-fitted into the bearing hole 22.
, And a plurality of needle rollers 33 that can roll along the raceway surface 32 on the inner periphery of the cylindrical portion 31a. The outer ring 31 is a press-formed product of a thin metal plate.

In the universal joint having the above structure, if there is a radial clearance Δr between the trunnion 24 of the spider 23 and the needle roller bearing 30, a play corresponding to the radial clearance between the connecting portions of the pair of yokes 20. Sticking,
Rotational torque cannot be smoothly transmitted between the two shafts connected to each yoke 20.

For this reason, in a steering device,
In order to improve the steering operability of the steering wheel,
There is a demand for a reduction in the radial clearance between the needle roller bearing and the trunnion.

To reduce the radial clearance, the tolerance of each component is reduced. However, except for the spider 23, the outer ring 31 of the yoke 20 and the needle roller bearing 30 is provided.
Since is a press-formed product, there is a limit naturally.

Therefore, conventionally, the bearing hole 22 of the yoke 20
, The trunnions 24 having an outer diameter suitable for the needle roller bearing 30 are selected and combined.

[0009]

As described above, the trunnion 24 is pressed against the needle roller bearing 30 after press-fitting.
There is a problem that the assembly is very troublesome in the universal joint for selectively combining the above.

An object of the present invention is to provide a shell-type needle roller bearing for a universal joint, which can reduce the radial clearance.

[0011]

In order to solve the above-mentioned problems, in the present invention, there is provided a thin metal plate having a bottom at one end of a cylindrical portion fitted into a bearing hole formed in a fork of a yoke. Outer ring, and a shell needle roller bearing for universal joint comprising a plurality of needle rollers that can roll along the inner raceway surface of the cylindrical portion.
At least one needle roller is configured as an oversized product whose outer diameter deviates to the plus side from the maximum mutual difference between the other needle rollers.

Here, since the radial clearance of the shell-shaped needle roller bearing, which is actually a problem, is about 5 μm, an oversized needle roller having a diameter larger than the other needle rollers by 5 μm or more is used. What was there is good.

As described above, by using at least one needle roller having an oversize having a larger outer diameter than the other needle rollers, the trunnion of the spider is inserted into the shell-shaped needle roller bearing. Then, the oversized needle roller is pressed in the outer diameter direction, and the shell-shaped needle roller bearing is deformed into an elliptical shape, and the deformation can reduce the radial clearance.

Here, if the hardness of the oversized needle rollers is set smaller than the hardness of the remaining needle rollers, the oversized needle rollers become elastic with respect to the other remaining needle rollers. Since the needle roller is easily deformed, the contact pressure of the needle roller at a position facing the oversized needle roller with respect to the trunnion can be reduced, which is effective in preventing damage to the needle roller and the trunnion. In this case, the oversized needle rollers may be made of plastic and made of a different material from the other needle rollers.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. As shown, the shell needle roller bearing A includes an outer ring 1 and a plurality of needle rollers 10.

The outer race 1 is formed by press-forming a thin metal plate, and has a bottom 3 at one end of a cylindrical portion 2.

The plurality of needle rollers 10 are rotatable along the raceway surface 4 on the inner periphery of the cylindrical portion 2 and are prevented from falling off by a flange 5 provided at the other end of the cylindrical portion 2.

Of the plurality of needle rollers 10, one of the needle rollers 10a has an outer diameter that is larger than the average of the outer diameters of the remaining rolling elements 10.

Here, the needle roller of a shell-type needle roller bearing used for a universal joint usually has a tolerance of an average of the outer diameter of about 0 to -10 μm and a maximum mutual difference of the outer diameter of about 3 μm. Is used. The radial clearance, which is actually a problem when such a shell needle roller bearing is incorporated in a universal joint, is about 5 μm.

Therefore, in the embodiment, as the oversized needle roller 10a, a needle roller about 5 μm larger than the outer diameter of the other remaining needle rollers 10 is employed.

In the shell-shaped needle roller bearing A having the above structure, the cylindrical portion 2 of the outer ring 1 is press-fitted into a bearing hole 22 formed in a fork 21 of a yoke 20 shown in FIG. The trunnion 24 is inserted into the needle roller 10, and the trunnion 24 is rotatably supported.

Here, the outer diameter of the trunnion 24 is the same as that of the remaining needle rollers 1 except for the oversized needle rollers 10a.
0, and the trunnion 24 is inserted into the needle roller 10 of the shell-shaped needle roller bearing A when the trunnion 24 is inserted into the oversized needle roller 10a.
Is pressed in the outer diameter direction by contact with the trunnion 24, so that the outer ring 1 is deformed into an elliptical shape as shown in FIG. 2, and the radial ring formed between the shell-shaped needle roller bearing and the trunnion 24 is formed. Clearance can be reduced.

In the above-described shell-shaped needle roller bearing, if the hardness of the oversized needle roller 10a is set lower than the hardness of the other needle rollers 10, the oversized needle roller 10a is pressed against the trunnion 24. Needle roller 10a of the size
Since the needle roller 10 is more easily elastically deformed than the other needle rollers 10, the contact pressure of the needle roller 10 located at the position facing the oversized needle roller 10a with respect to the trunnion 24 can be reduced. For this reason, mutual damage of the needle roller 10 and the trunnion 24 can be prevented, and the durability can be improved.

Here, the oversized needle roller 10a
As a method of reducing the hardness of the needle roller 10, a method of making the needle roller 10a different from the material of the other needle rollers 10 can be adopted. For example, oversized needle rollers 1
0a may be a plastic molded product.

In the embodiment, of the plurality of needle rollers 10, one needle roller 10a is an oversized product, but two or more needle rollers 10a may be an oversized product. In this case, the oversized needle roller 10a
Are not arranged at the opposing position.

[0026]

As described above, according to the present invention, of the plurality of needle rollers incorporated in the shell-shaped outer ring, at least one needle roller has a maximum mutual difference between the other needle rollers. Since it is a larger oversized product, the insertion of the trunnion causes the oversized needle roller to be pressed in the outer diameter direction due to the insertion of the trunnion, causing the outer ring to deform into an elliptical shape. The radial clearance between the trunnions can be reduced.

[Brief description of the drawings]

FIG. 1 (I) is a longitudinal sectional front view of a shell-shaped needle roller bearing according to the present invention, and FIG. 1 (II) is a partially enlarged sectional view thereof.

FIG. 2 is a cross-sectional plan view showing a state where the trunnion of the spider is supported by the shell-shaped needle roller bearing of the above.

FIG. 3 (I) is a longitudinal sectional front view of a universal joint using a conventional shell-shaped needle roller bearing, and FIG. 3 (II) is an enlarged sectional view taken along line aa of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Outer ring 2 Cylindrical part 3 Bottom 10, 10a Needle roller

Claims (5)

[Claims] An outer ring made of a thin metal plate having a bottom at one end of a cylindrical portion fitted into a bearing hole formed in a fork of a yoke, and rolling along an inner raceway surface of the cylindrical portion. A shell-type needle roller bearing for a universal joint, comprising: a plurality of free needle rollers; at least one of the plurality of needle rollers;
A shell type needle roller bearing for a universal joint, wherein one needle roller is an oversized product whose outer diameter deviates to the plus side from the maximum mutual difference between the other needle rollers. 2. The shell needle for universal joint according to claim 1, wherein the outer diameter of the oversized needle roller is larger than the average outer diameter of the other remaining needle rollers by 5 μm or more. Roller bearing. 3. The shell-type needle roller for a universal joint according to claim 1, wherein the oversized needle roller is set lower than the hardness of the other remaining needle rollers. bearing. 4. The needle roller bearing for a universal joint according to claim 3, wherein the oversized needle roller is made of a material different from that of the other remaining needle rollers. 5. The needle roller bearing for a universal joint according to claim 4, wherein said oversized needle roller is formed of a plastic molded product.