JP2000220655A - Tripod joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tripod joint which can secure the inner diameter of a roller without impairing the assemblage of a snap ring, and can obtain a constant velocity joint, compact, high in transmission capability high in capacity. SOLUTION: A roller 4 is rotatably supported by a trunnion 3 extended in the radial direction from a boss 2 forming up a tripod joint by way of a needle bearing in such a way that it can be rotated and moved in the axial direction. A needle retainer 12 is coupled with the tip end of the trunnion 3. The opposite part 12a faced to the needle bearing 9 and a come-out prevention part 12b trying to prevent the roller 4 from coming off, are formed in a needle retainer 12. The wall thickness of the opposite part 12a of the needle retainer 12 is made thicker than that of the come-out prevention part 12b. The needle retainer 12 is restricted by a snap ring 11 fitted in the annular groove 10 of the trunnion 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roller which is supported by three trunnions each extending in a radial direction from a tripod shaft and which rolls along a roller groove of a tulip shaft in pair with each trunnion. The present invention relates to a tripod joint having a torque transmitting member.

[0002]

2. Description of the Related Art FIG. 6 is a sectional view showing a general tripod joint. A boss 2 is fixed to an end of the driven shaft 1 of the tripod joint. Three trunnions 3 extend in the radial direction on the outer periphery of the boss portion 2, and a roller 4 having an outer spherical surface is rotatably supported on each trunnion 3 so as to rotate and move in the axial direction of the trunnion 3. . The roller 4 is rotatably fitted in a roller groove 6 which forms an inner spherical surface in the longitudinal direction facing each other at three positions corresponding to the trunnion 3 of the tulip 5.
A drive shaft 7 is integrally connected to an end of the tulip 5.

In the above-mentioned tripod joint,
The torque to be transmitted is determined by pressing each roller 4 against the roller groove 6 in the direction in which the torque is to be transmitted.
To be transmitted between them. And each roller 4
In order for the roller to smoothly roll without receiving harmful resistance during torque transmission, a gap is formed between the opposing roller groove 6 and the outer surface of the roller 4. That is, the gap is made equal to the difference between the diameter of the inner spherical surface formed in the roller groove 6 facing the outer ring and the diameter of the outer spherical surface of the roller 4.

FIG. 5 is an explanatory diagram showing a mounting structure of the roller 4 and the trunnion 3. As shown in FIG. A needle bearing 9 is disposed on the trunnion 3 extending in the radial direction of the boss 2. A snap ring 11 is engaged with an annular groove 10 formed at the tip of the trunnion 3. The needle retainer 12 fitted to the tip of the trunnion 3 is positioned by the snap ring 11.

The needle retainer 12 has a ring-shaped facing portion 12 a facing the needle bearing 9.
And an opposing portion 12a to prevent the roller 4 from slipping out.
And a falling-off preventing portion 12b whose front end is larger in diameter than the base end.

[0006] The needle retainer 12 prevents the needle bearing 9 from coming off outward. The roller 4 having an outer spherical surface is supported by the trunnion 3 via a needle bearing 9.
The roller 4 is fitted in a roller groove 6 of a tulip 5.

The needle retainer 12 configured as described above is provided for preventing the roller 4 and the needle bearing 9 from coming off during assembly and preventing the needle bearing 9 from coming off during operation. Have been.

[0008]

By the way, in recent years, as market needs have demanded a compact, high-capacity constant velocity joint having a large torque transmission capability, the needle retainer 12 from the needle bearing 9 has been required. The push-up load of the needle retainer 12 has increased, and the load resistance of the needle retainer 12 has been required to be enhanced.

Therefore, in order to enhance the above load resistance,
It is conceivable to increase the thickness of the needle retainer 12. However, if the thickness of the needle retainer 12 is uniformly increased, when the snap ring 11 is assembled to the annular groove 10 of the trunnion 3 as shown by the solid line in FIG. There is a problem that the distance between the outer peripheral surface of the trunnion 3 and the outer peripheral surface of the trunnion 3 becomes shorter, the distance S1 between the outer peripheral surface of the snap ring 11 fitted to the trunnion 3 becomes narrower, and the assemblability of the snap ring 11 deteriorates. Further, after the thickness of the needle retainer 12 is increased,
Although it is conceivable to increase the inner diameter of the roller 4 so that the distance between the roller b and the outer peripheral surface of the trunnion 3 does not become narrower, it is not possible to increase the inner diameter of the roller 4 because the load resistance of the roller 4 at the time of torque transmission decreases. There is a problem that cannot be done.

For this reason, snap ring assemblability and
Since it is necessary to secure the inner diameter of the roller, there has been a problem that the thickness of the needle retainer cannot be uniformly increased. SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and it is possible to secure the inner diameter of the roller without deteriorating the snap ring assemblability, and to reduce the torque transmission capacity. It is an object of the present invention to provide a tripod joint capable of obtaining a high-capacity constant velocity joint having a large value.

[0011]

According to a first aspect of the present invention, a roller is rotatable and axially movable via needle bearings to three trunnions extending radially from a boss portion, respectively. Axle-supported, this roller is fitted in a roller groove of a tulip shaft, and in a tripod joint formed by fitting a needle retainer to the tip of the trunnion, the needle retainer has an opposing portion facing a needle bearing; A tripod joint including a pull-out preventing portion for preventing the roller from falling out of the trunnion, and a load-resisting improving means which is substantially thicker than the pull-out preventing portion on the side facing the needle retainer. It is assumed that.

According to a second aspect of the present invention, in the first aspect, the load resistance improving means includes a tripod joint in which the thickness of the facing portion of the needle retainer is greater than the thickness of the stopper portion. It is.

According to a third aspect of the present invention, in the second aspect, the needle retainer includes a tripod joint formed by press forming so that the opposing portion is formed so as to be deviated so as to be thicker than the detachment preventing portion. It is assumed that.

According to a fourth aspect of the present invention, in the first aspect, the load resistance improving means is constituted by a ring member interposed between the facing portion of the needle retainer and the needle bearing and fitted to the trunnion. The gist of this is a tripod joint.

According to a fifth aspect of the present invention, a roller is rotatably and axially movable on three trunnions each extending radially from a boss via a needle bearing, and the roller is a tulip. In a tripod joint formed by fitting a needle retainer at a tip end of the trunnion, the trunnion is fitted into a roller groove of a shaft, the trunnion has a first portion into which a facing portion facing the needle bearing fits, and a needle bearing. The present invention includes a tripod joint that includes a second portion that is in sliding contact with the first portion and a diameter of the first portion is smaller than a diameter of the second portion.

According to a sixth aspect of the present invention, in the fifth aspect, a peripheral groove for fitting a snap ring for restraining a needle retainer is formed at a tip portion of the trunnion,
Of the parts, the fixing part to which the needle retainer is fixed has an axial length of the trunnion substantially equal to the thickness of the facing part of the needle retainer from the circumferential groove, and the fixing part and the needle bearing of the trunnion are in sliding contact with each other. The gist is a tripod joint that is spaced apart from the site.

(Function) According to the first aspect of the present invention, the needle retainer is separated from the needle bearing by the load resistance improving means which is substantially thicker than the pull-out preventing part on the opposing portion side of the needle retainer. It is possible to cope with an increase in the pushing load. For this reason, the snap ring assemblability is not deteriorated, the inner diameter of the roller can be secured, and a compact, high-capacity constant velocity joint having a large torque transmission capability can be obtained.

According to the second aspect of the present invention, the load resistance improving means is configured such that the thickness of the facing portion of the needle retainer is larger than the thickness of the pull-out preventing portion. Can be realized.

According to the third aspect of the present invention, the needle retainer can be formed by press forming so that the opposing portion is deviated so as to be thicker than the stopper portion, thereby facilitating manufacture. .

According to the fourth aspect of the invention, the function of the first aspect can be realized by the ring member fitted to the trunnion between the facing portion of the needle retainer and the needle bearing.

According to the fifth aspect of the present invention, by making the diameter of the first portion of the trunnion smaller than the diameter of the second portion, the insertability of the snap ring is not lost.
The thickness of the needle retainer can be increased. By increasing the thickness of the needle retainer, it is possible to cope with an increase in the pushing load of the needle retainer from the needle bearing.

Further, since the first portion of the trunnion has a small diameter, the snap ring assemblability is not deteriorated, and the inner diameter of the roller can be ensured. A constant velocity joint can be obtained.

According to the sixth aspect of the present invention, the fixing portion where the needle retainer is fixed and the portion where the needle bearing slides are separated from each other. There is no stress concentration during use.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A first embodiment in which the present invention is embodied in a constant velocity joint used in an automobile will be described below with reference to FIGS. In the configuration of the tripod joint, the same components as those shown in FIGS. 5 and 6 are denoted by the same reference numerals, and different portions will be mainly described.

FIG. 1 is a sectional view of a principal part of a tripod joint, and FIG. 2 is an enlarged sectional view of the principal part. The tripod joint of the present embodiment includes a driven shaft 1, a boss 2, three trunnions 3, and a roller 4, similarly to the tripod joint of FIG. 6.

A needle bearing 9 is disposed on the trunnion 3 extending in the radial direction of the boss 2. An annular groove 10 as a circumferential groove is formed at the tip of the trunnion 3, and a snap ring 11 is engaged with the annular groove 10.

The roller 4 having an outer spherical surface is supported on the trunnion 3 via a needle bearing 9, and the roller 4 is fitted in the roller groove 6 of the tulip 5.

This embodiment is different from the conventional example in the structure of the needle retainer 12. The needle retainer 12 according to the present embodiment is formed by a ring-shaped facing portion 12a facing the needle bearing 9 by press molding.
In order to prevent the roller 4 from slipping out, a drop-out preventing portion 12b is formed so as to rise from the outer peripheral edge of the facing portion 12a, and the leading end portion is larger in diameter than the base end side. And
The difference from the conventional example is that the thickness t1 of the facing portion 12a is uneven by press molding so as to be larger than the thickness t2 of the slip-out preventing portion 12b. The configuration in which the thickness t1 of the facing portion 12a is made thicker than the thickness t2 of the slip-off preventing portion 12b constitutes the load-resistance improving means.

The outer diameter S3 of the outer periphery of the leading end of the slip-off preventing portion 12b is longer than the inner diameter S2 of the roller 4 as in the conventional example. The needle retainer 12 thus configured is provided with the roller 4 and the needle bearing 9 at the time of assembly.
And is provided to prevent the needle bearing 9 from coming off during operation, and is restrained by the snap ring 11.

According to the constant velocity joint 10 having the above structure,
The following operational effects are obtained. (1) In the present embodiment, the thickness of the facing portion 12a of the needle retainer 12 is made thicker than the thickness of the pull-out preventing portion 12b. As a result, it is possible to cope with an increase in the thrust load from the needle bearing 9 to the needle retainer 12.

Also, the stopper 1 for the needle retainer 12
2b has the same thickness as the conventional one, so that when the snap ring 11 is assembled to the annular groove 10 of the trunnion 3,
The distance between the stopper 12b of the needle retainer 12 and the outer peripheral surface of the trunnion 3 does not become short, that is,
The distance S1 between the outer peripheral surface of the snap ring 11 and the snap ring 11 fitted to the trunnion 3 does not become short, and the assemblability of the snap ring 11 does not deteriorate.

Further, the inner diameter of the roller 4 can be ensured as in the prior art, and a compact, high-capacity constant velocity joint having a large torque transmission capability can be obtained. (2)
In the present embodiment, the needle retainer 12 is formed by press molding so that the opposed portion 12a is thicker than the slip-out preventing portion 12b.

As a result, when the thickness of the needle retainer 12 is uneven, the needle retainer 12 can be formed easily, and the manufacture can be easily performed. (Second Embodiment) Next, a second embodiment will be described with reference to FIG. In this embodiment, the facing portion 12a of the needle retainer 12 and the detachment preventing portion 12b
Are formed to have the same thickness as each other by press molding. Further, the trunnion 3 is fitted between the facing portion 12a and the needle bearing 9 so as to interpose a washer 14 as a ring member having a predetermined thickness and having a surface with which the needle bearing 9 can contact when the needle bearing 9 is pushed up. Have been combined. As a result, the total thickness of the facing portion 12a and the washer 14 is larger than the thickness of the detachment preventing portion 12b.

The washer 14 constitutes a means for improving the load resistance. By doing so, even if the thrust load from the needle bearing 9 to the needle retainer 12 increases, it is possible to cope with this by making the washer 14 share the thrust load. Also, when assembling the snap ring 11 into the annular groove 10 of the trunnion 3,
Since the thickness of the stopper 12b of the needle retainer 12 is the same as that of the related art, the distance between the stopper 12b of the needle retainer 12 and the outer peripheral surface of the trunnion 3 is not reduced. The distance S1 between the snap ring 11 to be fitted and the outer peripheral surface does not become short, and the assemblability of the snap ring 11 does not deteriorate.

Further, the inner diameter of the roller 4 can be ensured as in the prior art, and a compact, high-capacity constant velocity joint having a large torque transmission capability can be obtained. (Third Embodiment) Third Embodiment Will be described with reference to FIG.

In this embodiment, the distal end portion of the trunnion 3 has a small diameter portion 3A extending from the distal end surface to the base end side of the trunnion 3 beyond the annular groove 10 up to a predetermined length (the axial length of the trunnion 3). The base end side is larger diameter portion 3B
It has been. The small diameter part 3A is a first part, and the large diameter part 3B is a second part. Further, a portion of the small diameter portion 3A on the proximal end side of the trunnion 3 from the annular groove 10 is a fixing portion 3C when the needle retainer 12 is finally fitted and is restrained by the snap ring 11, and its length is set. The length (the axial length of the trunnion 3) is the same as the thickness of the facing portion 12a of the needle retainer 12. In the large diameter portion 3B of the trunnion 3, the needle retainer 1
2 is a part that slides on the trunnion 3 (sliding part) 3
D is arranged at a distance from the fixing portion 3C.

In this embodiment, the thickness of the needle retainer 12 is made uniformly thicker than in the conventional example, and the facing portion 12a and the slip-off preventing portion 12b are made to have the same thickness. I have.

The snap ring 11 has a smaller inner and outer diameter than the snap ring 11 of the first embodiment so that the snap ring 11 can be fitted into the annular groove 10 of the small diameter portion 3A. It may be the same size as one embodiment.

The third embodiment configured as described above has the following operational effects. (1) In the present embodiment, the entire thickness of the needle retainer 12 can be increased by making the diameter of the small diameter portion 3A of the trunnion 3 smaller than the diameter of the large diameter portion 3B.
By increasing the thickness of the needle retainer 12, the needle retainer 1 from the needle bearing 9 is removed.
2 can be increased.
Further, even if the thickness of the needle retainer 12 is made larger than the conventional one, the snap ring 11 engaged with the annular groove 10 of the trunnion 3 has an inner and outer diameter smaller than that of the conventional one, and is fitted to the trunnion 3. Therefore, the assemblability to the trunnion 3 does not deteriorate.

As described above, the snap ring 11 does not deteriorate in the assemblability, the inner diameter of the roller 4 can be secured, and a compact, high-capacity constant velocity joint having a large torque transmission capability can be obtained. be able to.

(2) In this embodiment, in the trunnion 3, the sliding contact portion 3D where the needle retainer 12 is in sliding contact with the trunnion 3 is arranged more apart than the fixed portion 3C, and the fixed portion 3C is From the annular groove 10 to the trunnion 3 having the same thickness as the thickness of the facing portion 12a of the needle retainer 12.
Formed in the axial direction.

As a result, since the fixed part 3C and the part (sliding part) 3D that the needle bearing 9 slides are separated from each other, a joint is not used at the step that separates the small diameter part 3A and the large diameter part 3B. Sometimes stress concentration does not occur.

The present invention is not limited to the above embodiment, but may be implemented as follows. (1) In the first embodiment, the needle retainer 12
Was formed by press molding, but a plate having a uniform thickness may be formed by press forming and then grinding the slip-off preventing portion 12b to be thinner than the facing portion 12a.

(2) In the second embodiment, the facing portion 12a of the needle retainer 12 and the slip-off preventing portion 12b have the same thickness as in the prior art, but the thickness of the facing portion 12a is reduced. After being thicker than 12b, a washer 14 having a predetermined thickness may be provided. In this case, it is possible to improve the load resistance more than the second embodiment.

(3) In the structure of the second embodiment, the thickness of the facing portion 12a of the needle retainer 12 and the thickness t1 of the facing portion 12a are replaced with the thickness of the facing portion 12a instead of having the same thickness.
And the washer 14 having a predetermined thickness t3 is fitted to the trunnion 3 to reduce the total thickness (t1 + t3) of the facing portion 12a and the washer 14. The thickness may be greater than the thickness t2 of the detachment prevention portion 12b.

In this case, the same operation and effect as in the second embodiment can be obtained. (4) In the second embodiment, the number of washers 14 is one, but may be two, or three or more. As the number of washers 14 increases, the thrust load from needle bearing 9 can be shared, and the effect of preventing damage to needle retainer 12 can be enhanced.

(5) In the configuration of the third embodiment, the opposing portion 12a of the needle retainer 12 and the detachment preventing portion 12b
Instead of having the same thickness, the thickness t1 of the facing portion 12a may be greater than the thickness t2 (t1> t2) of the removal preventing portion 12b.

In this case, the same operation and effect as in the third embodiment can be obtained. Here, in addition to the technical ideas described in the claims, technical ideas grasped by the above-described embodiments are listed below together with their effects.

(1) The needle retainer according to claim 5 or 6, wherein the needle retainer includes a facing portion facing the needle bearing, and a pull-out preventing portion for preventing the roller from coming off. A tripod joint with the same thickness as the thickness of the dropout prevention part. With such a configuration, a plate having a uniform thickness can be used as a material before the needle retainer is formed.

[0050]

As described in detail above, according to the first to fourth aspects of the present invention, the snap ring assemblability is not deteriorated, and the inner diameter of the roller can be secured.
A compact, high-capacity constant velocity joint having a large torque transmission capability can be obtained. Even if the input load to the tripod joint increases, it is possible to prevent the needle retainer from being damaged by the thrust load from the needle bearing.

In the case of a structure in which the roller gets over the needle retainer, which is often adopted in a large-angle tripod joint, the configuration of the invention according to claim 2 or 3 adopts the structure in which the roller is at a large angle. It is possible to prevent the needle retainer from being damaged due to the thrust load from the needle bearing without increasing the overload generated when trying to get out of the retainer.

According to the fifth and sixth aspects of the present invention, the thickness of the needle bearing can be increased by making the diameter of the first portion of the trunnion smaller than the diameter of the second portion. As a result, it is possible to cope with an increase in the thrust load of the needle retainer from the needle bearing. For this reason, the snap ring assemblability is not deteriorated, the inner diameter of the roller can be secured, and a compact, high-capacity constant velocity joint having a large torque transmission capability can be obtained.

According to the sixth aspect of the present invention, since the fixed portion to which the needle retainer is fixed and the portion where the needle bearing slides are separated from each other, No stress concentration occurs when the joint is used, and the trunnion is not damaged.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a main part, similarly.

FIG. 3 is a sectional view of a main part of a second embodiment.

FIG. 4 is a sectional view of a main part of a third embodiment.

FIG. 5 is a sectional view of a main part of a conventional tripod joint.

FIG. 6 is a sectional view of a tripod joint.

[Explanation of symbols]

2. Boss part, 3 ... trunnion, 3A ... small diameter part (constituting first part), 3B ... large diameter part (constituting second part), 3C ... first part, 3D ... second part, 4 ... roller, 5 ... tulip, 6 ... roller groove, 9 ... needle bearing, 10 ... annular groove (constituting a circumferential groove), 11 ...
Snap ring, 12: needle retainer, 12a: opposing portion, 12b: detachment preventing portion, 14: washer (constitutes a ring member).

Claims (6)

[Claims] 1. A roller is rotatably and axially movable via needle bearings on three trunnions each extending radially from a boss portion, and the rollers are supported on roller grooves of a tulip shaft. In a tripod joint formed by fitting and fitting a needle retainer to a tip portion of the trunnion, the needle retainer has an opposing portion facing a needle bearing, and a slip-off preventing portion for preventing the roller from slipping out of the trunnion. A tripod joint, comprising: a load-bearing-enhancing means that is substantially thicker than a pull-out preventing part is provided on a facing side of the needle retainer. 2. The tripod joint according to claim 1, wherein said load resistance improving means is formed by making a thickness of an opposing portion of said needle retainer larger than a thickness of a prevention portion. 3. The tripod joint according to claim 2, wherein the needle retainer is formed by press forming so that the opposing portion is deviated so as to be thicker than the slip-off preventing portion. 4. The device according to claim 1, wherein the load resistance improving means is constituted by a ring member interposed between a facing portion of the needle retainer and a needle bearing and fitted to a trunnion. Tripod joint. 5. A roller is rotatably supported on three trunnions extending in the radial direction from the boss portion via needle bearings so as to be rotatable and movable in the axial direction. In the tripod joint formed by fitting and fitting a needle retainer to a tip portion of the trunnion, the trunnion has a first portion into which a facing portion facing the needle bearing is fitted, and a second portion in sliding contact with the needle bearing. Wherein the diameter of the first portion is smaller than the diameter of the second portion. 6. A peripheral groove for fitting a snap ring for restraining the needle retainer is formed at a tip end of the trunnion, and a fixing part of the first part to which the needle retainer is fixed is the peripheral groove. The tripod joint according to claim 5, further comprising an axial length of the trunnion substantially equal to the thickness of the facing portion of the needle retainer, and wherein the fixed portion and a portion where the needle bearing of the trunnion slides are separated from each other.