JPS594173Y2 - needle bearing - Google Patents

Description

[Detailed description of the invention] The invention uses a roller that is supported by three trunnions each extending in the radial direction from the tripod shaft, and that moves along the roller groove of the tulip shaft that pairs with each trunnion. The present invention relates to a needle bearing suitable for use in a tripod joint used as a torque transmission member.

FIG. 1 is an explanatory diagram showing a general tripod joint.

Three trunnions 3 extend in the radial direction on the outer periphery of the tripod 2 connected to the end of the first shaft 1, and each trunnion 3 has a hemispherical outer periphery through a needle 4. A roller 5 is supported rotatably and movably in the axial direction of the trunnion 3.

The rollers 5 are removably fitted into roller grooves 7 that form inner spherical surfaces in the longitudinal direction facing each other in the three-position lid corresponding to the trunnion 3 of the tulip 6, and a second shaft is attached to the end of the tulip 6. 8 are connected.

Transmission torque between the first shaft 1 and the second shaft 8 in such a tripod joint is transmitted via the trunnion 3, needle 4, roller 5, and tulip 6.

Further, when transmitting torque with a joint angle between the first shaft 1 and the second shaft B, the roller 5 rotates and moves in the axial direction relative to the trunnion 3.

FIG. 2 is an explanatory diagram showing a conventional needle bearing structure in such a tripod joint.

A conical chamfer 5A is formed on the inner diameter portion of the outer end surface of the roller 5 which is pivotally supported by the trunnion 3 via the needle 4.
is formed, and a retainer 9 is attached to the end of the trunnion 3 in a state in which it is positioned by contacting a tapered surface with a snap ring 11 that is locked in an annular groove 10 formed at the end of the trunnion 3. ing.

The retainer 9 has a conical shape, and the thrust receiving surface 9A formed on the inner surface of the retainer 9 contacts the end surface of the needle 4 to prevent the needle 4 from coming off in the axial direction. 5A to restrict the predetermined axial movement of the roller 5 and prevent the roller 5 from coming off from the trunnion 3.

However, in such a conventional tripod joint needle bearing structure, the first shaft 1 and the second shaft
When the needle 4 has a joint angle with the shaft 8 to transmit torque, the needle 4 is pushed in one direction by the action of the roller 5 which not only rotates but also moves in the axial direction as described above.
One end surface of the needle 4 rotates on its own axis while being pressed against one of the retainers 9 and 12, and also revolves around the trunnion 3. Therefore, the revolution speed at one end of the needle 4 is the same as the revolution speed at the other end. As shown in FIG. 3, the needle 4 revolves around the trunnion 3 with its axis skewed from its normal state.

This tendency of skew in the needle 4 is caused by the roller 5 on the loaded side as shown in FIG.
However, on the side where the load is not applied, the clearance between the needle 4 and the inner circumferential surface of the roller 5 is large and the needle 4 is Skew tends to occur.

When the needle 4 is in a skewed state, that is, when it revolves obliquely and comes to the side where the load is applied, the surface pressure applied to the needle 4 suddenly increases, which can lead to an accident where the needle 4 breaks. This has the disadvantage that the durability of the transfer surface of the trunnion 3 cannot be maintained satisfactorily.

The present invention was devised in view of the above-mentioned conventional problems, and an object of the present invention is to provide a needle bearing that prevents needle skew.

To achieve this purpose, a groove is formed on at least one of the inner circumferential surface of the rolling element or the outer circumferential surface of the shaft in the same direction as the axis of the shaft, into which the needle can be retractably inserted. It is.

Embodiments of the present invention will be described below with reference to the drawings.

Figures 4a and 4l) are a front view of a partially broken main part and a sectional view taken along the line B-B in a, showing an embodiment of a tripod joint that employs a needle bearing according to the present invention, and are the same as the conventional one. The same reference numerals are given to the parts, and the explanation thereof will be omitted.

On the inner circumferential surface of a rolling element (roller 13 in this embodiment) which is rotatably and axially movably supported via a needle 4 on the outer circumference of a shaft (trunnion 3 in this embodiment), A groove 14 is provided so as to be in the same direction as the axis of the trunnion 3.

This groove 14 is shaped so that the needle 4 can be inserted into it, and the distance H, which is the sum of the depth to the bottom of the groove 14 with respect to the perfect circle 15 and the height to the peak 16 with respect to the perfect circle, is the diameter 2 of the needle 4. It is formed to a depth of 5μ to 10μ for ~3mm (see Fig. 5).

To explain this in more detail, for example, in this embodiment, when the needle 4 and trunnion 3 are in contact with each other under load, the load is P (kg), the needle length is l (mm),
The needle diameter is d (mm), the trunnion diameter is D (mm)
), the contact width between the needle 4 and the trunnion 3 is 2b (mm
), then b becomes.

Here, d=2 (mm), D=20 (mm),
1=13 (mm).

Assuming Pm2O3 (kg), 1) #0.056m
m.

Therefore, the radial displacement amount δ between the trunnion 3 and the needle 4 is as follows.

Furthermore, since there is a similar displacement between the needle 4 and the roller 13, the total displacement is about 0.003 mm=3μ.

On the other hand, when the petal-shaped crowning is finished on the inner surface of the roller 13 and the needle 4 under load is elastically deformed, the needle 4 and the trunnion 3 in the bulge of the petal, and the needle 4 and the roller 13 There must be enough space between them to allow for slight movement.

Therefore, if the gaps between the needle 4 and the roller 13 in the bulge of the petal, and between the third needle 4 and the trunnion 3 are, for example, 3μ, then the above-mentioned H=about 6μ.

In this way, the depth of the groove 14 is made extremely small relative to the diameter of the needle 4, that is, the groove 14 is shaped smoothly. It is structured so that it can be used in

Note that the number of grooves 14 is 1 for every 2 to 5 needles 4.
The cross section is shaped like a flower petal, as shown in detail in FIG. 5.

Therefore, in the needle bearing structure configured in this way, when a load is applied, several needles 4
escapes into the groove 14 and is maintained parallel to the trunnion 3, so the remaining needles 4 are also corrected parallel to the trunnion 3.

Therefore, on the side where the load is not applied, the needle 4
Even if the clearance between the roller 13 and the inner circumferential surface of the roller 13 becomes larger, the skew of the needle 4 as in the conventional case can be reliably prevented. It is possible to maintain good durability and service life of the transfer surface.

In the above-described embodiment, the grooves 14 are provided only on the inner circumferential surface of the roller 13, but the grooves 14 are not limited to this. It may be provided on both of the outer circumferential surfaces of the trunnion 3, and it goes without saying that even with such a structure, the same effect as the above-mentioned embodiment can be obtained.

As explained above, according to the twenty-one dollar bear nong according to the present invention, at least one of the inner circumferential surface of the rolling element and the outer circumferential surface of the shaft is provided with a groove formed in such a way that the needle can be retractably inserted into the axis of the shaft. With this configuration, needle skew can be reliably prevented even on the side where the load is not applied.
Therefore, it is possible to prevent needle breakage accidents, and
This has the effect of maintaining good durability and life of the transfer surface of the shaft.

[Brief explanation of drawings]

Figure 1 is a sectional view showing a general tripod joint, Figure 2 is a sectional view showing the needle bearing structure of a conventional tripod joint, Figure 3 is a partial perspective view of a conventional needle bearing, and Figure 4. a, l) are a partially broken front view of an embodiment of a tripod joint that employs a needle bearing according to the present invention, and a sectional view taken along line B-B in a, and Fig. 5 is an enlarged view of the main part of a rolling element. FIG. 3...Trunion, 4...Needle,
13...Roller, 14...Groove.

Claims (2)

[Scope of utility model registration request] (1) A groove is formed on at least one of the inner circumferential surface of the rolling element or the outer circumferential surface of the shaft so that the needle can be retractably inserted thereinto in the same direction as the axis of the shaft. needle bearing. (2) The scope of the utility model registration claim, wherein the grooves are provided at regular intervals in the circumferential direction and have a petal-shaped cross section, and the depth of the grooves is extremely small relative to the diameter of the needle. The needle bearing described in item (1).