JP2001208090A - Constant speed universal coupling - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a contact speed universal coupling in which improvements in endurability and strength has been attained. SOLUTION: A locking means is composed of a locking ring 33 on one side of a roller mechanism A and composed of a locking flange 34e on the other side thereof. The locking ring 33 is fixedly fitted into a circumferential groove 34c formed on the inner periphery of the end on one side of a roller 34. The locking flange 34e is formed integrally with the end on the other side of the roller 34. The locking ring 33, by fitting, for example, with interference into the bottom of circumferential groove 34c, can be made free from backlash in radial direction in relation to the roller 34. The locking flange 34e, on the other hand, has no axial or radial backlash in the roller 34, since the locking flange 34e is formed integrally with the roller 34.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a constant velocity universal joint used for a power transmission device of an automobile or various industrial machines, and more particularly to a tripod type constant velocity universal joint.

[0002]

2. Description of the Related Art For example, as one element of a power transmission device for transmitting rotational power from an automobile engine to wheels (as a coupling for connecting a drive shaft or a propeller shaft),
A tripod type constant velocity universal joint is used.

In general, a tripod type constant velocity universal joint has an outer joint member having three axial track grooves formed on an inner peripheral portion thereof and having an axial roller guide surface on both sides of each track groove, and a radius. It has three leg axes protruding in the directions,
A tripod member in which a roller is rotatably arranged on each leg shaft is mainly configured. When the leg shaft of the tripod member and the roller guide surface of the outer joint member engage in the rotational direction via the roller, rotational torque is transmitted at a constant speed from the driving side to the driven side. In addition, the relative axial displacement and angular displacement between the outer joint member and the tripod member are absorbed by each roller rolling on the roller guide surface while rotating with respect to the leg axis, When the outer joint member and the tripod member transmit rotational torque while maintaining an operating angle, the axial displacement of each leg shaft with respect to the roller guide surface due to the change in the rotational direction phase is absorbed.

As a tripod type constant velocity universal joint, there is a type in which the above roller is mounted on a cylindrical outer peripheral surface of a leg shaft via a plurality of needle rollers, but the outer joint member and the tripod member take an operating angle while taking an operating angle. When transmitting rotational torque,
Since the rollers and the roller guide surface obliquely intersect with each other with the inclination of the leg shaft, slippage occurs between the two, and the sliding resistance at that time hinders the smooth rolling of each roller. There is a problem that the induced thrust increases. Also,
Due to the sliding resistance between each roller and the roller guide surface, there is a problem that the sliding resistance when the outer joint member and the tripod member are relatively displaced in the axial direction increases.

Therefore, in order to eliminate the oblique state between the roller and the roller guide surface and to reduce induced thrust and slide resistance, a mechanism (roller mechanism) for freely tilting and axially moving the roller with respect to the leg shaft. A variety of tripod-type constant velocity universal joints having the following have been proposed and put into practical use. As a tripod-type constant velocity universal joint of this type, a roller mechanism (roller assembly) is formed by forming the outer peripheral surface of a leg shaft into a convex spherical shape and rotatably assembling a roller to a support ring via a plurality of needle rollers. A configuration is known in which a cylindrical inner peripheral surface of a support ring is externally fitted to a convex spherical outer peripheral surface of a leg shaft (Japanese Patent Publication No. 7-117108, Japanese Patent No. 26232).
No. 16, etc.). According to this configuration, by the slip between the cylindrical inner peripheral surface of the support ring and the convex spherical outer peripheral surface of the leg shaft,
Tilt and axial movement of the roller mechanism with respect to the leg shaft become free.

Further, the present applicant has proposed that the inner peripheral surface of the support ring has an arc-shaped convex cross section in order to more effectively reduce induced thrust and slide resistance in this type of tripod type constant velocity universal joint. Has an outer peripheral surface that is straight in a longitudinal section and contacts an inner peripheral surface of the support ring in a direction perpendicular to the axis of the joint in a transverse cross section, and between an inner peripheral surface of the support ring in the axial direction of the joint. A configuration for forming a gap has already been filed (Japanese Patent Application No. 11-0559040). According to this configuration, the sliding between the inner peripheral surface of the arc-shaped convex cross section of the support ring and the straight outer peripheral surface of the leg shaft allows the roller mechanism to tilt and move in the axial direction with respect to the leg shaft.

[0007]

In this kind of constant velocity universal joint, the relative movement of the roller and the support ring in their axial direction is restricted from both sides by locking means, so that the assembly of the roller mechanism is provided. Assures unity. On the other hand, when this kind of constant velocity universal joint transmits rotational torque while maintaining an operating angle, the roller mechanism tilts with respect to the leg shaft and moves in the axial direction, so that the inner peripheral surface of the support ring and the outer peripheral surface of the leg shaft are moved. Slip occurs, and due to the sliding frictional force, an axial repetitive load (hereinafter simply referred to as “axial load”) directed in the axial direction of the roller and the support ring is applied to the locking means. Therefore, the locking means is required to have a strength (strength against bending fatigue, cracking fatigue, etc.) that can withstand this axial load. In addition, when the locking means is in sliding contact with the end surface of the roller or the support ring, and further, when the roller is rotatably supported by the needle roller with respect to the support ring, the end surface of the needle roller also comes into sliding contact. Becomes

According to the present invention, in a tripod type constant velocity universal joint having a roller mechanism as described above, a locking means, in particular, a fatigue strength against an axial load of a locking ring mounted on a roller or a support ring is increased. In addition, by increasing the fatigue life of the contact surface, we provide a tripod-type constant velocity universal joint that has superior durability and strength while maintaining the current size, and also secures durability and strength equal to or higher than the current product It is another object of the present invention to provide a more compact tripod type constant velocity universal joint.

[0009]

In order to achieve the above object, according to the present invention, three axial track grooves are formed in an inner peripheral portion, and axial roller guide surfaces are provided on both sides of each track groove. Outer joint member having a radially projecting 3
A tripod member having a plurality of leg shafts, and a roller mechanism mounted on each leg shaft of the tripod member, and the roller mechanism is guided along a roller guide surface in a direction parallel to the axis of the outer joint member. A roller, a support ring rotatably supporting the roller, and locking means for restricting relative movement of the roller and the support ring in the axial direction from both sides, respectively, and tilting with respect to the axis of the leg shaft. And a constant velocity universal joint that is movable in the axial direction, at least one of the locking means has a locking ring mounted on a roller or a support ring, and the thickness W of the locking ring is 0.5 mm ≦ W
≦ 1.2 mm and the surface hardness of the locking ring is H
A configuration that is not less than RC43 and not more than HRC53 is provided.

Here, the "at least one of the locking means has a locking ring mounted on a roller or a support ring" has a structure in which one of the locking means is a locking ring and the other of the locking means is a locking ring. A configuration in which the means is a locking flange integrally provided on a roller or a support ring, and a configuration in which both locking means on both sides are both locking rings are included. Further, a locking means including at least one locking means including a locking ring and another locking element, for example, a locking means including a locking ring and a locking flange is also included. Further, the “locking ring” includes not only an integral ring having a complete ring shape but also a split ring in which a part is split by a slit.

When the thickness W of the locking ring is 0.5 mm ≦ W ≦
The reason for setting it to 1.2 mm is as follows. As described above, the locking ring receives the axial repetitive load via the roller (or the support ring) or the needle roller. From the viewpoint of increasing the responsiveness to the axial load and increasing the fatigue strength,
It is important that the locking ring has an appropriate toughness.
That is, by imparting appropriate toughness to the locking ring, the axial load applied to the locking ring is dispersed, and as a result, the fatigue strength of the locking ring is improved. In addition, in this type of constant velocity universal joint, the locking ring is often mounted on a roller or a support ring while reducing and expanding the diameter of the locking ring. From the viewpoint of assemblability, the locking ring may have appropriate toughness. desirable. Furthermore, from the viewpoint of simplifying the manufacturing process, it is desirable to consider the formability of the locking ring. By setting the thickness W of the locking ring to a value within the range of 0.5 mm ≦ W ≦ 1.2 mm, the locking ring is given an appropriate toughness, and the fatigue strength against an axial load is improved. The assemblability to the roller or the support ring can be improved. In addition, the formability of the locking ring is improved.

On the other hand, the surface of the locking ring should be given an appropriate hardness to ensure good wear resistance from the viewpoint of increasing the fatigue strength against the axial load and increasing the fatigue life of the contact surface. desirable. HRC4 surface hardness of locking ring
The reason for setting the range of 3 to HRC 53 is as described above.
Here, "HRC" represents the C scale of Rockwell hardness. If the surface hardness is less than HRC43, the fatigue life of the contact surface cannot be sufficiently ensured, and if the surface hardness exceeds HRC53, the toughness is reduced and the fatigue strength against the axial load and the ease of assembly are reduced. At a disadvantage.

In the above configuration, at least the surface layer of the locking ring may have a structure containing a spherical carbide in a matrix of martensite. Here, “at least the surface layer has a structure containing a spherical carbide in the martensite matrix” includes those having only the surface layer having the above structure and those having the above structure from the surface to the inside.

According to this structure, at least the surface layer structure of the locking ring contains a spherical carbide in a martensite matrix, so that the wear resistance is higher than that of general structural steel. As a result, the fatigue life of the contact surface is improved.

The above-mentioned spherical carbide is a carbide mainly composed of Fe ₃ C. The structure containing such a spherical carbide in the martensitic matrix has at least the eutectoid point or more (0.8 wt% or more) in the surface layer. It can be formed by containing carbon C and performing quenching and tempering.

More specifically, the locking ring can be formed of carbon tool steel, and the amount of spherical carbide in the martensite matrix can be 0.3 to 0.6 wt%. According to this configuration, since a proper amount of finely spheroidized carbide is contained in the martensite matrix, high wear resistance can be obtained, and at the same time, the matrix is not significantly hardened and has a moderate toughness. Become. Therefore, the fatigue life of the contact surface of the locking ring is improved, and the fatigue strength against an axial load is also improved. In addition, by securing the appropriate toughness of the locking ring, the assemblability to the roller or the support ring is improved. Here, it is preferable that the amount of the spherical carbide in the martensite base is regulated within the range of 0.3 to 0.6 wt%. If the amount of the spherical carbide is less than 0.3 wt%, the effect of improving the wear resistance cannot be sufficiently obtained. Conversely, if the amount of the spherical carbide exceeds 0.6 wt%, the toughness of the matrix becomes too low and the fatigue strength with respect to the axial load. And the assemblability may be insufficient. As tool carbon steel, SK3, SK4, S
K5, SK6 and the like can be used.

Alternatively, the locking ring can be formed of spring steel. According to this configuration, a high elasticity limit is obtained while maintaining a high surface hardness, so that the fatigue life of the contact surface of the locking ring is improved, and the fatigue strength against an axial load is also improved. Further, since a high elasticity limit is obtained, the assemblability of the locking ring is further improved, which is effective in automating the assembling work and thereby reducing the manufacturing cost. The type of spring steel is not particularly limited, and the most suitable one can be selected from hot-formed spring steel and cold-formed spring steel according to the conditions of use and the joint size. SUP4 or the like can be used.

Further, the locking ring can be formed of a hard wire. Although the abrasion resistance is slightly inferior to the above configuration, the high elasticity limit allows the axial load applied to the locking ring to be dispersed, and as a result, a high fatigue strength with respect to the axial load is obtained. In addition, a high-hardness wire is relatively inexpensive and is also effective in improving the assemblability.
For example, SWRH or the like can be used as the high-hardness wire.

In the above configuration, it is preferable that the locking ring is mounted on the roller or the support ring without play. Here, "no backlash" means that the locking ring is incorporated in the roller or the support ring at least without any backlash in the radial direction. Preferably, not only play in the radial direction but also play in the axial direction is eliminated. According to this configuration, since the locking ring is attached to the roller or the support ring without looseness, the application region (load point) of the axial load received by the locking ring from the roller or the support ring is stabilized, and As a result, the fatigue strength with respect to the axial load is improved. In addition, since the fluctuation of the load point is suppressed, the fatigue life of the contact surface between the locking ring and the roller or the support ring is also improved.

Further, by forming the locking means on the other side as a locking flange integrally provided on a roller or a support ring,
Since the assembly tolerance when attaching the locking ring to this portion can be eliminated, the axial clearance between the locking means on both sides and the roller or the support ring can be reduced by half.
Thereby, the above effect can be made more remarkable.

In the above arrangement, minute concave portions may be formed at random on at least the contact surface of the locking means (locking ring and / or locking flange). The minute recesses formed on the contact surface serve as oil reservoirs and promote the formation of an oil film on the contact surface, so that lubricity is improved and the fatigue life of the contact surface is improved. The minute concave portion is, for example, about several tens μm in size and about 1 μm in depth. By changing the polishing conditions for the contact surface, it is possible to form minute recesses of any size, depth, and number. When it is difficult to selectively form the minute concave portion only on the contact surface, the minute concave portion may be formed including the peripheral portion of the contact surface, or the entire surface of the locking ring, the roller, or the support ring.

Further, a solid lubricating coating having a chemical conversion coating as a base layer may be formed on at least the contact surface of the locking means (locking ring and / or locking flange). The solid lubricating coating reduces the frictional resistance of the contact surface and improves the lubricity, thereby improving the fatigue life of the contact surface. The chemical conversion coating serving as an underlayer is formed for the purpose of increasing the adhesion of the solid lubricating coating to the contact surface. Examples of the chemical conversion coating include a manganese phosphate coating, an iron phosphate coating, and a zinc phosphate coating. Further, examples of the solid lubricating film include a molybdenum disulfide film, a PTFE film, and the like. In addition, since the surface roughness of the contact surface (base material surface) before the treatment affects the effect after the treatment, the surface roughness of the contact surface is set so as to obtain an appropriate oil sump action.
It is desirable to finish to Ra 0.2 to 0.8. If it is difficult to selectively apply the coating to the contact surface only, the coating may be applied to the periphery of the contact surface or to the entire surface of the locking ring, the roller, or the support ring.

[0023] At least the contact surface of the locking means (locking ring and / or locking flange) may be subjected to room-temperature sulfurizing treatment. Sulfurization treatment is a surface treatment method in which sulfur penetrates the surface of steel to generate iron sulfide. By performing the sulfurizing treatment, the friction resistance of the surface is reduced, so that the initial conformability is improved, the contact fatigue life is improved, and the NVH characteristics are also stabilized. Further, according to the room temperature sulfurizing treatment, for example, 3
Since processing is performed under the conditions of 0 to 40 ° C. × 10 to 30 minutes,
The hardness of the surface hardened layer does not decrease. Since the surface roughness of the contact surface before the treatment affects the effect after the treatment, the surface roughness of the contact surface is set to Ra so that an appropriate oil sump action can be obtained.
It is desirable to finish to 0.2 to 0.8. When it is difficult to selectively perform the sulfurizing treatment only on the contact surface, the sulfurating treatment may be performed including the peripheral portion of the contact surface or the entire surface of the locking ring, the roller, or the support ring.

Further, at least the contact surface of the locking means (locking ring and / or locking flange) may be subjected to a shot peening treatment. By appropriately adjusting the size of the shot particles, the projection speed, the projection amount, and the like, forming fine dimples on the contact surface, and making the fine dimples have a role of an oil reservoir, lubricity can be improved. Further, the shot peening treatment makes the surface structure finer and generates residual compressive stress on the surface, which is effective in improving the fatigue strength against an axial load and the fatigue life of the contact surface. If it is difficult to selectively perform shot peening only on the contact surface, the shot peening may be performed on the entire surface of the engaging ring, the roller, or the support ring, including the peripheral portion of the contact surface.

The roller mechanism of the constant velocity universal joint according to the present invention includes a roller guided on a roller guide surface, and a support ring externally fitted on the outer peripheral surface of the leg shaft and rotatably supporting the roller. The inner peripheral surface of the ring has an arc-shaped convex cross section, the outer peripheral surface of the leg shaft has a straight shape in a vertical cross section, and contacts the inner peripheral surface of the support ring in a direction perpendicular to the axis of the joint in a cross section, and In addition, it is possible to adopt a configuration in which a clearance is formed between the joint ring and the inner peripheral surface of the support ring in the axial direction of the joint.

The cross-sectional shape of the leg shaft may be such that it makes contact with the inner peripheral surface of the support ring in a direction perpendicular to the axis of the joint and forms a clearance with the inner peripheral surface of the support ring in the axial direction of the joint. In other words, the shape means a shape in which the surface portions of the tripod member facing each other in the axial direction are retracted in the mutual direction, that is, on the smaller diameter side than the virtual cylindrical surface. One specific example is a substantially elliptical shape. The “substantially elliptical shape” includes not only an elliptical shape as it is literally but also a shape generally called an oval shape, an oval shape, or the like.

By adopting the above-mentioned cross-sectional shape of the leg shaft, which has been conventionally circular, when the joint takes an operating angle, the leg shaft can be connected to the outer joint member without changing the attitude of the roller mechanism (roller assembly). Can lean against. Moreover, since the contact ellipse between the outer peripheral surface of the leg shaft and the support ring approaches a point from the conventional horizontally long shape (see FIG. 1C), the friction moment for tilting the roller mechanism is reduced. Therefore, the attitude of the roller mechanism is always stable, and the roller can be smoothly rolled because the roller is held parallel to the roller guide surface. This contributes to a reduction in slide resistance and a reduction in induced thrust.

The roller mechanism plays a role of transmitting torque by interposing between the leg shaft and the outer joint member. In this kind of constant velocity universal joint, the direction of torque transmission is always the axis of the joint. Since the direction is perpendicular to the direction of transmission, torque can be transmitted by contact between the leg shaft and the support ring in the torque transmission direction. There is no hindrance.

In the above configuration, the generatrix on the inner peripheral surface of the support ring can be constituted by the arc portion at the center and the escape portions at both ends. It is preferable that the radius of curvature of the arc portion is set to a value that allows the inclination of the leg axis of about 2 to 3 °. In addition, a plurality of rolling elements can be arranged between the support ring and the roller to make the support ring and the roller relatively rotatable,
Needle rollers, balls and the like can be used as the rolling elements. Further, the outer peripheral surface of the roller is formed into a spherical shape (a “true spherical surface” whose center of curvature is on the axis of the leg axis, or a so-called “torus surface” in which the center of curvature is offset toward the outer diameter side from the axis of the leg axis). In addition, the spherical outer peripheral surface of the roller may be in angular contact with the roller guide surface of the outer joint member. By making angular contact between the roller and the roller guide surface, the roller is less likely to oscillate and its posture is further stabilized, so that when the roller moves in the axial direction of the outer joint member, the roller smoothly moves on the roller guide surface with less resistance. To roll. As a specific configuration for realizing such an angular contact, a cross-sectional shape of the roller guide surface may be a tapered shape or a gothic arch shape.

The roller mechanism of the constant velocity universal joint according to the present invention includes a roller guided on a roller guide surface, and a support ring which is fitted on the outer peripheral surface of the leg shaft and rotatably supports the roller. The outer peripheral surface of the leg shaft is convex spherical, and the inner peripheral surface of the support ring is cylindrical or conical.

[0031]

Embodiments of the present invention will be described below.

FIGS. 1 and 2 show a first embodiment of the present invention. 1 (A) shows a cross section of the joint, FIG. 1 (B) shows a cross section perpendicular to the leg axis, FIG. 1 (C) shows a cross section of the support ring, and FIG. 2 shows the operating angle (θ). 3 shows a longitudinal section of the joint in a taken state.

As shown in FIG. 1, the constant velocity universal joint mainly comprises an outer joint member 10 and a tripod member 20. One of the two shafts to be connected is connected to the outer joint member 10, and the other is a tripod member. 20.

The outer joint member 10 has three track grooves 12 extending in the axial direction in the inner peripheral portion. The roller guide surfaces 1 are respectively provided on circumferentially opposite side walls of each track groove 12.
4 are formed. The tripod member 20 has three radially protruding leg shafts 22, and a roller 34 is mounted on each leg shaft 22, and the rollers 34 are housed in the track grooves 12 of the outer joint member 10. . The outer peripheral surface 34 a of the roller 34 is a convex curved surface that matches the roller guide surface 14.

Here, the outer peripheral surface 34a of the roller 34 is a convex curved surface having an arc having a center of curvature at a position radially away from the axis of the leg shaft 22 as a generating line.
Has a gothic arch shape, whereby the outer peripheral surface 34a of the roller 34 and the roller guide surface 14 form an angular contact. In FIG. 1A, two contact positions are indicated by alternate long and short dash lines. Even if the cross-sectional shape of the roller guide surface 14 is tapered with respect to the outer peripheral surface of the spherical roller, angular contact between the two can be realized. By adopting a configuration in which the outer peripheral surface 34a of the roller 34 and the roller guide surface 14 form an angular contact, the roller is less likely to oscillate, and the posture is stabilized. When the angular contact is not used, for example, the roller guide surface 14 is formed by a part of a cylindrical surface whose axis is parallel to the axis of the outer joint member 10, and its cross-sectional shape is formed by a bus bar of the outer peripheral surface 34 a of the roller 34. May be an arc corresponding to.

A support ring 32 is attached to the outer peripheral surface 22a of the leg shaft 22.
Is fitted outside. The support ring 32 and the roller 34 are assembled (unitized) via a plurality of needle rollers 36, and constitute a roller mechanism (roller assembly) A that can rotate relatively. That is, as shown in an enlarged manner in FIG. 5, the cylindrical outer peripheral surface of the support ring 32 is defined as an inner race surface, and the cylindrical inner peripheral surface of the roller 34 is defined as an outer race surface. Roller 36
Are provided so as to be able to roll freely. And the support ring 3
In order to restrict the relative movement of the roller 2, the roller 34 and the needle roller 36 in their axial direction, locking means are provided on both axial sides of the roller mechanism A, respectively. In this embodiment, the locking means on both sides are formed by locking rings 33 and 35, which are fitted into circumferential grooves 34c and 34d provided on the inner circumference of the end of the roller 34, respectively.
The width W of the locking rings 33 and 35 is 0.5 mm ≦ W ≦ 1.2
mm and the surface hardness is HRC47 ~
It is defined within the range of HRC57. Thereby, the fatigue strength against the axial load from the support ring 32 and the needle roller 36 can be increased, and the fatigue life of the contact surface due to the contact with the support ring 32 and the needle roller 36 can be improved. The locking rings 33 and 35 are
c, 34d, the engagement rings 33, 3
5 is resiliently reduced in diameter, incorporated into the inner periphery of the end of the roller 34, and advanced to the position where the circumferential grooves 34c and 34d are formed. Then, the locking rings 33 and 35 are
When it reaches the position where c and 34d are formed, it is elastically expanded and restored, and fits into the circumferential grooves 34c and 34d. In this manner, the locking rings 33, 35 attached to the rollers 34
Restricts the movement of these members relative to the roller 34 in the axial direction by contacting the end surface of the support ring 32 and the end surface of the needle roller 36. The locking rings 33 and 35 are, for example, split rings partially divided by slits. Further, as shown in FIG. 1 (B), the needle roller 36 is incorporated in a so-called full-roller state in which as many rollers as possible are inserted and there is no retainer.

The outer peripheral surface 22a of the leg shaft 22 has a longitudinal section {FIG.
(A)} has a straight shape parallel to the axis of the leg shaft 22, and a cross section {FIG. 1 (B)} has an elliptical shape whose major axis is orthogonal to the axis of the joint. The cross-sectional shape of the leg shaft is
The thickness of the tripod member 20 as viewed in the axial direction is reduced, and the tripod member 20 has a substantially elliptical shape. In other words, the cross-sectional shape of the leg shaft is
The surfaces of the tripod members facing each other in the axial direction are retracted in the mutual direction, that is, on the smaller diameter side than the virtual cylindrical surface.

The inner peripheral surface 32c of the support ring 32 has an arc-shaped convex cross section. That is, the generatrix of the inner peripheral surface 32c has the radius r
{FIG. 1 (C)}. This and the leg shaft 22
Has a substantially elliptical cross section as described above,
Since a predetermined clearance is provided between the support ring 32 and the support ring 32, the support ring 32 can not only move in the axial direction of the leg shaft 22, but also can tilt with respect to the leg shaft 22. . Further, as described above, the support ring 32 and the roller 3
4 is assembled (unitized) so as to be rotatable relative to each other via a needle roller 36, so that the support ring 32 and the roller 34 can be tilted as a unit with respect to the leg shaft 22. Here, the tilt refers to the support ring 3 with respect to the axis of the leg shaft 22 in a plane including the axis of the leg shaft 22.
2 and the axis of the roller 34 are inclined (see FIG. 2).

In the case of this type of conventional joint, since the outer peripheral surface of the leg shaft is in contact with the inner peripheral surface of the support ring over the entire circumference, the contact ellipse has a horizontally elongated shape extending in the circumferential direction. for that reason,
When the leg axle is inclined with respect to the outer joint member, a frictional moment is generated which acts to incline the support ring and thus the roller with the movement of the axle. On the other hand, in the embodiment shown in FIG. 1, the cross section of the leg shaft 22 is substantially elliptical, and the cross section of the inner peripheral surface 32c of the support ring 32 is an arc-shaped convex cross section. As shown by the broken line in C),
The contact ellipse of both becomes close to a point, and at the same time the area becomes smaller. Therefore, the roller mechanism (32, 33, 3)
4, 35, 36) is greatly reduced as compared with the conventional one, and the posture stability of the roller 34 is further improved.

In the above configuration, the locking rings 33, 35
In addition, by performing the above-described various material improvements and surface modifications, the fatigue strength against the axial load from the support ring 32 and the needle roller 36 is further increased, and the support ring 32
And the fatigue life of the contact surface accompanying the contact with the needle roller 36 can be further improved. Furthermore, the locking ring 3
This effect can be further enhanced by mounting the rollers 3 and 35 in the circumferential grooves 34c and 34d of the roller 34 without play. In this embodiment, the locking rings 33, 3
By fitting the outer periphery of 5 into the groove bottoms of the circumferential grooves 34c and 34d with interference, radial play between the locking rings 33 and 35 and the roller 34 is eliminated.

FIGS. 6 to 12 show other examples of the structure of the roller mechanism A. FIG.

In the embodiment shown in FIG. 6, the locking means on one side of the roller mechanism A is formed by a locking ring 33, and the locking means on the other side is formed by a locking collar 34e. The locking ring 33 is fitted in a circumferential groove 34 c provided on the inner circumference of one end of the roller 34. The locking flange 34e is provided integrally with the other end of the roller 34. The locking ring 33 can be fitted to the groove bottom of the circumferential groove 34c with a tightening margin, for example, to eliminate radial play between the locking ring 33 and the roller 34. Since the locking flange 34 e is provided integrally with the roller 34, there is no axial play or radial play between the locking flange 34 e and the roller 34. Compared to the embodiment shown in FIG. 5, it is possible to eliminate the assembly tolerance by forming the locking means on the other side with a locking ring, and to reduce the axial clearance between the support ring 32 and the needle roller 36 by half. There are advantages. The formation portion of the locking flange 34e is
The end of the roller 34 facing the base end of the roller or the end of the roller facing the front end of the leg may be either. Is provided. Width W
Other items such as the hardness and the surface hardness conform to the embodiment shown in FIG.

In the embodiment shown in FIG. 7, similarly to the embodiment shown in FIG. 5, the locking means on both axial sides of the roller mechanism A are constituted by locking rings 33, 35. In this case, the locking rings 33, 35 have step portions 33a, 35 having a taper (taper angle β) in a direction of expanding the diameter outward.
a, and the steps 33a and 35a are fitted to the inner circumference of the end of the roller 34 with interference. Thereby, radial play between the locking rings 33 and 35 and the roller 34 can be eliminated. Further, since the axial load from the support ring 32 and the needle roller 36 can be received at the contact portion S 'between the step portions 33a and 35a and the inner periphery of the end of the roller 34, the bending fatigue of the locking rings 33 and 35 can be improved. It is also effective for prevention. The outer circumferences of the locking rings 33 and 35 and the circumferential groove 34
There is a slight radial gap between c and 34d. Further, the locking rings 33 and 35 are, for example, divided rings partially divided by slits. Other items such as the width W and the surface hardness conform to the embodiment shown in FIG.

The embodiment shown in FIG.
Tapered surfaces 33b, 35b, 34c1, 34 that are taperedly fitted to the outer periphery of 35 and the side walls of circumferential grooves 34c, 34d.
d1 is provided. The taper surfaces 33b and 35b of the locking rings 33 and 35 are taperedly fitted to the tapered surfaces 34c1 and 34d1 of the circumferential grooves 34c and 34d with an interference, so that the gap between the locking rings 33 and 35 and the roller 34 is increased. Radial play and axial play can be eliminated. Although the locking rings 33 and 35 may be split rings, FIG.
Alternatively, it may be constituted by an integral ring as shown in FIG. That is, the annular portion 33c (35) of the locking ring 33 (35)
c) is formed in an inclined state in a natural state, and after the roller 34 is inserted to the position where the circumferential groove 34c (34d) is formed, an axial force P is applied to elastically raise the annular portion 33c (35c). Deform. Then, the annular portion 33c (35)
The outer circumference of c) is enlarged in diameter and fitted in the circumferential groove 34c (34d), whereby the locking rings 33 and 35 are fitted and fixed in the circumferential groove 34c (34d) of the roller 34. Other items such as the width W and the hardness are in accordance with the embodiment shown in FIG.

In the embodiment shown in FIG. 10, the locking means on both sides of the roller mechanism A are formed by locking rings 33 'and 35', and the locking rings 33 'and 35' are
Are fitted into the circumferential grooves 32d and 32e provided on the outer periphery of the end portion of the rim. When fitting the locking rings 33 ′, 35 ′ into the circumferential grooves 32d, 34e,
3 ′ and 35 ′ are elastically expanded in diameter, incorporated into the outer periphery of the end of the support ring 32, and pushed to the position where the circumferential grooves 32d and 34e are formed. Then, the locking rings 33 ', 3
When 5 ′ reaches the position where the circumferential grooves 32d and 34e are formed, the diameter is elastically reduced and restored, and fitted into the circumferential grooves 32d and 34e. In this way, the locking rings 33 ′ and 35 ′ attached to the support ring 32 come into contact with the end surface of the roller 34 and the end surface of the needle roller 36, so that these members move in the axial direction with respect to the support ring 32. Restrict relative movement to. In this embodiment, the locking rings 33 ', 3
By fitting the inner periphery of 5 ′ to the groove bottoms of the circumferential grooves 32d and 34e with interference, radial play between the locking rings 33 ′ and 35 ′ and the support ring 32 is eliminated. The locking rings 33 'and 35' are, for example, split rings partially divided by slits. Other items such as the width W and surface hardness are in accordance with the embodiment shown in FIG.

In the embodiment shown in FIG. 11, the locking means on one side of the roller mechanism A is formed by a locking ring 33 ', and the locking means on the other side is formed by a locking flange 32f. The locking ring 33 ′ is fitted into a circumferential groove 32 d provided on the outer periphery of one end of the support ring 32. In addition, locking collar 3
2 f is provided integrally with the other end of the support ring 32. The locking ring 33 ′ can be fitted to the groove bottom of the circumferential groove 32 d with a tight allowance, for example, to eliminate radial play between the locking ring 33 ′ and the support ring 32. Since the locking flange 32 f is provided integrally with the support ring 32, there is no axial play or radial play between the locking flange 32 f and the support ring 32.
Compared with the embodiment shown in FIG. 10, there is an advantage that the axial clearance between the roller 34 and the needle roller 36 can be reduced to half by eliminating the assembly tolerance due to the fact that the locking means on the other side is formed by a locking ring. There is. In addition, the locking flange 32
The formation portion of f may be either the end of the support ring 32 facing the base end of the leg shaft or the end of the support ring 32 facing the front end of the leg shaft. A locking flange 32f is provided at the end facing the. Other items such as the width W and the surface hardness conform to the embodiment shown in FIG.

In the embodiment shown in FIG. 12, the locking means on one side of the roller mechanism A is formed by a locking ring 33 and a locking flange 32g, and the locking means on the other side is formed by a locking flange 34e. It is. The locking ring 33 is fitted into a circumferential groove 34 c provided on the inner circumference of one end of the roller 34. Also,
The locking flange 32g is integrally provided at one end of the support ring 32. The locking flange 34e is provided integrally with the other end of the roller 34. The locking ring 33 can be fitted to the groove bottom of the circumferential groove 34c with a tightening margin, for example, to eliminate radial play between the locking ring 33 and the roller 34. Since the locking flange 32g is provided integrally with the support ring 32, there is no axial play or radial play between the locking ring 32g and the support ring 32. In addition, since the locking flange 34 e is provided integrally with the roller 34, there is no axial play or radial play between the locking flange 34 e and the roller 34. Other items such as the width W and the surface hardness conform to the embodiment shown in FIG.

In the above embodiment, various shapes shown in FIG. 13 can be adopted as the end surface shape of the needle roller 36. FIG. 3A shows an end surface of the needle roller 36 as a hemispherical surface having a radius of curvature R′1, and FIG.
(C) shows an end surface of the needle roller 36 having a partially spherical surface with a radius of curvature R'2, and (C) shows an end surface of the needle roller 36 having a flat surface and a chamfer cf at a corner. ) Indicates that the end face of the needle roller 36 has a radius of curvature R'3.
And r ′ (R′3> r ′).

FIGS. 3 and 4 show another embodiment of the present invention. In this embodiment, while the generatrix of the inner peripheral surface 32c of the support ring 32 is formed by a single arc in the above embodiment, the center arc portion 32a and the escape portions 32b on both sides of the center arc portion 32a are formed. They differ in that they are formed in combination. The escape portion 32b is a portion for avoiding interference with the leg shaft 22 when the operating angle (θ) is taken as shown in FIG. 3C, and extends from the end of the arc portion 32a to the end of the support ring 32. It is composed of a straight line or a curve whose diameter gradually increases. Here, an example is shown in which the relief portion 32b is a part of a conical surface having a cone angle α = 50 °. The arc portion 32a
In order to allow the inclination of the leg shaft 22 with respect to the support ring 32 by about 2 to 3 °, a large radius of curvature (r) of, for example, about 30 mm is set. In the tripod-type constant velocity universal joint, the tripod member 20 swings about the center of the outer joint member 10 three times when the outer joint member 10 makes one rotation.
At this time, the amount of eccentricity represented by the symbol e {FIG. 2 (A)} increases in proportion to the operating angle (θ). And three leg axes 2
2 are separated from each other by 120 °, but when the operating angle (θ) is taken, as shown in FIG. 2 (B), when considering the vertical leg shaft 22 shown on the upper side of the figure as a base, Are slightly inclined from their axes at the operating angle 0 shown by the dashed line. The inclination is about 2 to 3 ° when the operating angle (θ) is, for example, about 23 °. Since this inclination is naturally allowed by the curvature of the circular arc portion 32a of the inner peripheral surface 32c of the support ring 32, it is possible to prevent the surface pressure at the contact portion between the leg shaft 22 and the support ring 32 from becoming excessively high. it can. FIG. 2B schematically shows the three leg shafts 22 of the tripod member 20 viewed from the left side surface of FIG. 2A, and the solid lines represent the leg shafts. The configuration and effect of the locking mechanism of the roller mechanism A are the same as those of the embodiment shown in FIGS. 1, 2, and 5. Further, various configurations shown in FIGS. 6 to 12 can be employed as the locking means of the roller mechanism A, and various configurations shown in FIG. 13 can be employed as the end surface shape of the needle roller 36.

FIGS. 14 and 15 show another embodiment of the present invention. FIG. 15 shows that the operating angle of the joint is 0 °.
And a state when no rotational torque is applied to the joint.

The tripod type constant velocity universal joint of this embodiment has an outer joint member 1 connected to one of two shafts to be connected.
And a tripod member 2 coupled to the other.

The outer joint member 1 has a substantially cup-like appearance, and three track grooves 1a extending in the axial direction are formed in the inner periphery at equal circumferential positions. Roller guide surfaces 1a1 are provided on both sides of each track groove 1a.

The tripod member 2 has a radially projecting 3
The leg shafts 2a are provided at equally circumferential positions. The outer peripheral surface 2a1 of each leg shaft 2a is formed in a convex spherical shape.
A roller mechanism A ′ in which a support ring 3, a plurality of needle rollers 4, and a roller 5 are assembled is mounted.

As shown in an enlarged manner in FIG. 14B, the roller mechanism A ′ includes a plurality of needles between a cylindrical outer peripheral surface 3 a of the support ring 3 and a cylindrical inner peripheral surface 5 a of the roller 5. The roller 4 is rotatably interposed, and the support ring 3 and both ends of the needle roller 4 are locked by a pair of locking rings 6 fitted on the inner peripheral surface 5 a of the roller 5. The axial movement (movement in the axial direction) of the needle roller 3 and the needle roller 4 is regulated.
The configuration and effect of the locking means of the roller mechanism A 'are the same as those of the embodiment shown in FIGS. 1, 2 and 5. 6 to 1 as locking means for the roller mechanism A '.
Various configurations shown in FIG. 2 can be adopted, and various shapes shown in FIG. 13 can be adopted as the end surface shape of the needle roller 4.

The inner peripheral surface 3b of the support ring 3 is fitted to the spherical outer peripheral surface 2a1 of the leg shaft 2a. In this embodiment, the inner peripheral surface 3b of the support ring 3 has a conical shape whose diameter gradually decreases toward the distal end of the leg shaft 2a, and the outer peripheral surface 2a1 of the leg shaft 2a.
Line contact with Thereby, the leg shaft 2a of the roller mechanism A '
Swinging is allowed. The inclination angle α of the inner peripheral surface 3b of the support ring 3 is as small as 0.1 ° to 3 °, preferably 0.1 ° to 1 °, and in this embodiment, α = 0.5 °. You have set. In the drawing, the inner peripheral surface 3b
The degree of the inclination is exaggerated.

The generatrix of the outer peripheral surface 5b of the roller 5 is
Is an arc centered on a point offset outward from the center of the circle.

In this embodiment, the cross-sectional shape of the roller guide surface 1a1 of the outer joint member 1 is a two-arc shape (gothic arch shape). Therefore, the roller guide surface 1a
1 and the outer peripheral surface 5b of the roller 5 make angular contact at two points p and q. The angular contact points p and q include the center of the outer peripheral surface 5b of the roller 5 and are located at the opposite sides of the center line orthogonal to the axis Z of the leg shaft 2a by the same distance in the axis Z direction. Incidentally, the cross-sectional shape of the roller guide surface 1a1 may be V-shaped or parabolic. Also, in this embodiment, the roller guide surface 1 is provided in the track groove 1a.
a1 is provided in the vicinity of the shoulder surface 1a2.
Thus, the end surface 5c of the roller 5 on the tip end side of the leg shaft is guided.

Since the inner peripheral surface 3b of the support ring 3 has a conical shape whose diameter gradually decreases toward the tip of the leg shaft, when a rotational torque is applied to this joint, as shown in FIG. The degree of inclination of the peripheral surface 3b is exaggerated more than in FIG. 14), and the contact position S between the inner peripheral surface 3b of the support ring 3 and the outer peripheral surface 2a1 of the leg shaft 2a is directed toward the tip end of the leg shaft. The generated load component F is generated. This load component F acts to push up the support ring 3 and the needle roller 4 toward the tip of the leg shaft, and the support ring 3 and the needle roller 4
Is pressed against the locking ring 6 on the tip of the leg shaft. Therefore, the contact position S between the inner peripheral surface 3b of the support ring 3 and the outer peripheral surface 2a1 of the leg shaft 2a is stabilized. The load component F acts via the support ring 3 and the needle roller 4 to push the roller 5 toward the tip of the leg shaft, thereby stabilizing the attitude of the roller 5 with respect to the roller guide surface 1a1. Such stabilization of the contact position S and stabilization of the attitude of the roller 5 effectively reduce and stabilize the induced thrust. The inner peripheral surface 3b of the support ring 3
May be cylindrical.

[0059]

EXAMPLE The following test was conducted to confirm the effect of setting the width W of the locking ring within a predetermined range and the effect of setting the surface hardness within the predetermined range.

[Test on Setting of Width W] In the configuration shown in FIGS. 1, 2 and 5, the width W of the locking ring is set to 0.5.
The test was performed under the following test conditions with the values set to be less than 0.8 mm, 1.0 mm, and more than 1.2 mm, and the fatigue strength with respect to the axial load, the assembling property to the roller, and the formability were evaluated. Table 1 shows the results. Evaluation item ○
Indicates that the target characteristic was satisfied, and Δ indicates that the target characteristic was not satisfied.

(Test conditions) Torque: 686 Nm, number of revolutions: 250 rpm, operating angle θ: 10 deg Test time: 300 h Surface hardness of locking ring: HRC50

[0062]

[Table 1]

From the test results shown in Table 1, by setting the thickness W of the locking ring in the range of 0.5 mm ≦ W ≦ 1.2 mm, the fatigue strength against the axial load, the assemblability to the roller, It was confirmed that good results were obtained in both the molding processability.

[Test Regarding Specification of Surface Hardness] In the configurations shown in FIGS. 1, 2 and 5, the surface hardness of the locking ring is set to less than HRC43, HRC47, HRC50, HRC5.
The test was performed under the following test conditions with the number exceeding 3, and the fatigue strength against the axial load and the fatigue life of the contact surface were evaluated. Table 2 shows the results. In the evaluation items, ○ indicates that the target characteristics could be satisfied, and △ indicates that the target characteristics could not be satisfied.

(Test conditions) Torque: 686 Nm, number of rotations: 250 rpm, operating angle θ: 10 deg Test time: 300 h Thickness of locking ring W: 0.8 mm

[0066]

[Table 2]

From the test results shown in Table 2, H of the locking ring
By defining within the range of RC43 to HRC53,
It was confirmed that good results were obtained in both the fatigue strength against the axial load and the fatigue life of the contact surface.

[0068]

According to the present invention, the fatigue strength of the locking means, especially the locking ring mounted on the roller or the support ring, against the axial load and the fatigue life of the contact surface are improved, so that the current size is maintained. It is possible to provide a tripod type constant velocity universal joint that is more excellent in durability and strength as it is, and to provide a more compact tripod type constant velocity universal joint while ensuring durability and strength equal to or higher than the current product. it can.

[Brief description of the drawings]

1A and 1B show an embodiment of the present invention, in which FIG. 1A is an end view showing a part of the cross section, FIG. 1B is a cross sectional view perpendicular to a leg axis in FIG. (C) is a sectional view of the support ring for explaining a contact ellipse.

2 (A) is a longitudinal sectional view of the constant velocity universal joint shown in FIG. 1 and shows a state where an operating angle is set, and FIG. 2 (B) is a view showing FIG.
It is a typical side view of a tripod member in (A).

3A and 3B show another embodiment of the present invention, in which FIG. 3A is an end view showing a part of the cross section, and FIG. 3B is a sectional view perpendicular to the leg axis in FIG. FIG. 3 (C) is a longitudinal sectional view showing a state where an operating angle is taken.

FIG. 4 is an enlarged sectional view of a support ring in FIG. 3;

FIG. 5 is a partially enlarged sectional view of the roller mechanism in FIGS. 1 and 2;

FIG. 6 is a partially enlarged cross-sectional view of a roller mechanism according to another embodiment.

7A is a partially enlarged sectional view of a roller mechanism according to another embodiment, and FIG. 7B is an enlarged view of a portion X in FIG. 7A.

8A is a partially enlarged cross-sectional view of a roller mechanism according to another embodiment, and FIG. 8B is an enlarged view of a portion Y in FIG. 8A.

FIG. 9 is a partial sectional view showing a locking ring.

FIG. 10 is a partially enlarged cross-sectional view of a roller mechanism according to another embodiment.

FIG. 11 is a partially enlarged cross-sectional view of a roller mechanism according to another embodiment.

FIG. 12 is a partially enlarged cross-sectional view of a roller mechanism according to another embodiment.

FIG. 13 is a partial side view showing an end surface of the needle roller.

FIG. 14 shows another embodiment of the present invention, and FIG.
FIG. 14B is an end view showing a part of the cross section, and FIG.
It is a partial expanded sectional view of (A).

15 is a view for explaining a load component F generated at a contact position between a support ring and a leg shaft in FIG. 14;

[Explanation of symbols]

 Reference Signs List 10 outer joint member 12 track groove 14 roller guide surface 20 tripod member 22 leg shaft 32 support ring 32a arc portion 32b relief portion 34 roller 36 needle roller 33, 33 'locking ring 35, 35' locking ring 34e locking flange 32f , 32g locking collar

Claims (14)

[Claims] An outer joint member having three axial track grooves formed on an inner peripheral portion thereof and having an axial roller guide surface on both sides of each track groove, and a radially projecting three groove groove.
A tripod member having two leg shafts, and a roller mechanism attached to each leg shaft of the tripod member,
The roller mechanism includes a roller guided in a direction parallel to an axis of an outer joint member along the roller guide surface, a support ring that rotatably supports the roller, and the roller and the support ring each including an axis. And a locking means for restricting relative movement in both directions from both sides. The constant velocity universal joint is capable of tilting and moving in the axial direction with respect to the axis of the leg shaft. A locking ring attached to the roller or the support ring, wherein the thickness W of the locking ring is 0.5 mm ≦ W ≦ 1.2 mm, and
The surface hardness of the locking ring is HRC43 or more, HRC5
A constant velocity universal joint characterized by being 3 or less. 2. The constant velocity universal joint according to claim 1, wherein at least a surface portion of the locking ring has a structure containing a spherical carbide in a matrix of martensite. 3. The locking ring is formed of carbon tool steel, and the amount of spherical carbide in the martensite matrix is equal to 0.
The constant velocity universal joint according to claim 3, wherein the content is 3 to 0.6 wt%. 4. The constant velocity universal joint according to claim 1, wherein said locking ring is made of spring steel. 5. The constant velocity universal joint according to claim 1, wherein said locking ring is formed of a hard steel wire. 6. The constant velocity universal joint according to claim 1, wherein the locking ring is mounted on the roller or the support ring without play. 7. The locking means on the other side is a locking flange integrally provided on the roller or the support ring.
7. The constant velocity universal joint according to any one of 6. 8. An infinite number of minute concave portions are formed at least on a contact surface of the locking means.
The constant velocity universal joint according to any one of the above. 9. The constant velocity universal joint according to claim 1, wherein a solid lubricating coating having a chemical conversion coating as a base layer is formed on at least a contact surface of said locking means. 10. The constant velocity universal joint according to claim 1, wherein at least a contact surface of the locking means is subjected to a normal temperature sulfurizing treatment. 11. The constant velocity universal joint according to claim 1, wherein at least a contact surface of said locking means is subjected to a shot peening process. 12. An inner peripheral surface of the support ring has an arc-shaped convex cross section, and an outer peripheral surface of the leg shaft has a straight shape in a vertical cross section, and has a cross section in a direction orthogonal to an axis of a joint in a cross section. The constant velocity universal joint according to any one of claims 1 to 11, wherein the constant velocity universal joint is configured to be in contact with an inner peripheral surface of the support ring and form a clearance between the inner peripheral surface of the support ring and the axial direction of the joint. . 13. The constant velocity universal joint according to claim 12, wherein a cross section of the leg shaft is substantially elliptical having a major axis orthogonal to an axis of the joint. 14. The constant velocity universal joint according to claim 1, wherein an outer peripheral surface of the leg shaft has a convex spherical shape, and an inner peripheral surface of the support ring has a cylindrical or conical shape.