WO2023189289A1

WO2023189289A1 - Tripod-type constant-velocity universal joint

Info

Publication number: WO2023189289A1
Application number: PCT/JP2023/008604
Authority: WO
Inventors: 卓板垣; 達朗杉山; 将太河田
Original assignee: Ntn株式会社
Priority date: 2022-03-30
Filing date: 2023-03-07
Publication date: 2023-10-05
Also published as: JP2023148090A

Abstract

In the present invention, an escape part 36, at which the tooth height of a female spline 34 is reduced, is provided to the inner circumference of the one-side end of a tripod member 3 in the axial direction. B/A>0.28 and C/D>0.23 are set, where: A represents the axial-direction distance from the one-side end surface of the tripod member 3 in the axial direction to a plane R including the axial center of each leg shaft 32; B represents the axial-direction distance from the one-side end surface of the tripod member 3 in the axial direction to the deep-side end P of the escape part 36; C represents the thickness of the tripod member 3 in a radial direction at the deep-side end P of the escape part 36 on an axial-direction cross-section that includes a joint axial center O and an intermediate part 33 and that extends in the tangential direction of a circle about the axis of a corresponding one of the leg shafts 32; and D represents the diameter of a tooth bottom 34a of the female spline 34.

Description

Tripod type constant velocity universal joint

The present invention relates to a tripod type constant velocity universal joint used for power transmission in automobiles and various industrial machines.

In drive shafts used in automobile power transmission systems, a sliding constant velocity universal joint is connected to the inboard side (the center side in the vehicle width direction) of the intermediate shaft, and the sliding constant velocity universal joint is connected to the outboard side (the end in the vehicle width direction). A fixed constant velocity universal joint is often connected to the side). The sliding type constant velocity universal joint referred to here allows both angular displacement and axial relative movement between two axes, while the fixed type constant velocity universal joint allows angular displacement between two axes. However, relative movement in the axial direction between the two axes is not permitted.

A tripod type constant velocity universal joint is known as a sliding type constant velocity universal joint. As this tripod type constant velocity universal joint, there are a single roller type and a double roller type. In the single roller type, a roller inserted into the track groove of the outer joint member is rotatably attached to the leg shaft of the tripod member via a plurality of needle rollers. The double roller type includes a roller that is inserted into a track groove of an outer joint member, and an inner ring that is fitted onto the leg shaft of a tripod member and rotatably supports the roller. The double roller type allows the roller to swing relative to the leg axis, so it reduces induced thrust (axial force induced by friction between parts inside the joint) and sliding resistance compared to the single roller type. Each has the advantage of being able to be reduced.

An example of a double roller type tripod constant velocity universal joint is disclosed in Patent Document 1 below.

JP2020-106087A

In the tripod type constant velocity universal joint described in Patent Document 1, the shaft is inserted into the center hole of the tripod member. Since the tripod member is coupled to the shaft by spline fitting so that torque can be transmitted, a load is repeatedly applied to the spline fitting portion of the tripod member depending on the condition of a vehicle such as an automobile.

On the inner circumferential surface of the tripod member, a slotted portion is formed at the end on the inlet side when inserting the shaft in a manner that reduces the tooth height of the female spline on the inner circumferential surface of the tripod member. At the boundary between the female spline and the hollow portion, the inner diameter end of the tooth surface of the female spline comes into edge contact with the tooth surface of the male spline, so the contact surface pressure at this edge contact portion increases. On the other hand, the thickness of the tripod member in the radial direction is the thinnest at the base of the leg shaft of the tripod member. Therefore, in the tripod member, it is necessary to increase the fatigue strength against repeated loads from the tooth bottom of the female spline at the same axial position as the edge contact portion to the root of the leg shaft.

Therefore, the present invention aims to increase the fatigue strength of the tripod member.

The tripod type constant velocity universal joint according to the present invention, which was made based on the above knowledge, is provided with track grooves extending in the axial direction at three locations in the circumferential direction, and each track groove is arranged to face each other in the circumferential direction. It has an outer joint member having a pair of roller guide surfaces. Further, the tripod type constant velocity universal joint includes a body portion having a female spline on the inner periphery, three leg shafts protruding in the radial direction of the body portion, and the legs located between the body portion and the leg shafts. The tripod member includes an intermediate portion having a concave curved cross section including the axis of the shaft. Furthermore, it has a roller attached to each of the leg shafts, and an inner ring that is fitted onto the leg shaft and rotatably supports the roller. In this tripod type constant velocity universal joint, the roller is movable in the axial direction along the roller guide surface, and the roller unit including the roller and the inner ring is swingable with respect to the leg shaft. be.

In this tripod type constant velocity universal joint, the present invention provides a recessed part in which the tooth height of the female spline is reduced on the inner periphery of one end of the tripod member in the axial direction, and The axial distance from one end surface to the plane containing the axis of each leg shaft is A, the axial distance from the end surface of the tripod member to the back end of the hollow part is B, and the axial distance of the leg shaft is B. On an axial cross section extending in the tangential direction of a circle centered on the axis and including the joint axis and the intermediate part, the thickness of the tripod member in the radial direction at the back end of the hollow part is C, It is characterized by setting the diameter dimension of the tooth bottom of the female spline as D, B/A>0.28 and C/D>0.23.

When B/A<0.28, the axial length of the hollow portion becomes relatively short. In this case, since the back end of the padded portion is shifted to one side in the axial direction of the tripod member, the thickness of the tripod member in the radial direction at the back end becomes thinner. If B/A>0.28, the wall thickness in the radial direction of the tripod member 3 at the rear end becomes sufficiently thick, making it possible to realize C/D>0.23. Therefore, the fatigue strength of the tripod member can be increased.

In this tripod type constant velocity universal joint, on the axial cross section of the tripod member, the outer peripheral surface of the tripod member gradually expands from the end surface of the tripod member toward a plane including the axis of each leg shaft. It can have a rounded profile.

In this case, the contour can be formed in a straight line in a region including the outer diameter side of the inner end of the bulge portion.

In the tripod type constant velocity universal joint described above, the inner circumferential surface of the inner ring has a convex arc shape in the longitudinal section of the inner ring, and the outer circumferential surface of the leg shaft has a longitudinal section including the axis of the leg shaft. The leg shaft has a straight shape in a plane and a substantially elliptical shape in a cross section perpendicular to the axis of the leg shaft, and the outer peripheral surface of the leg shaft contacts the inner peripheral surface of the inner ring in a direction perpendicular to the axial direction. At the same time, a gap may be provided between the inner ring and the inner circumferential surface of the inner ring in the axial direction.

According to the present invention, the fatigue strength of the tripod member can be increased.

FIG. 2 is an axial cross-sectional view showing a double roller type tripod constant velocity universal joint. 2 is a sectional view taken along line KK in FIG. 1. FIG. FIG. 2 is a cross-sectional view taken along line LL in FIG. 1. FIG. FIG. 2 is an axial cross-sectional view showing a state in which the tripod type constant velocity universal joint of FIG. 1 assumes an operating angle. FIG. 3 is a cross-sectional view showing a hardened layer formed on a tripod member. It is a front view of the tripod member seen in the axial direction from the opening side of the outer joint member. 7 is a sectional view taken along line MM in FIG. 6. FIG. FIG. 7 is a cross-sectional view taken along line XX in FIG. 6 of the tripod member with the shaft inserted into the inner periphery. FIG. 3 is a planar development of the spline fitting portion viewed from the radial direction. 7 is a sectional view taken along line XX in FIG. 6. FIG. 7 is a sectional view taken along the YY line in FIG. 6. FIG. FIG. 3 is a sectional view corresponding to FIG. 2 and showing another embodiment.

An embodiment of the tripod type constant velocity universal joint according to the present invention will be described based on FIGS. 1 to 12.

The tripod type constant velocity universal joint 1 of this embodiment shown in FIGS. 1 to 4 is a double roller type. Note that FIG. 1 is an axial cross-sectional view of a double roller type tripod constant velocity universal joint, and FIG. 2 is a cross-sectional view taken along the line KK in FIG. FIG. 3 is a cross-sectional view taken along line LL in FIG. 1, and FIG. 4 is a cross-sectional view in the axial direction showing the tripod type constant velocity universal joint at an operating angle. In the following description, "axial direction," "radial direction," and "circumferential direction" refer to the axial direction, radial direction, and circumferential direction of a tripod type constant velocity universal joint with an operating angle of 0° unless otherwise specified. and the circumferential direction, respectively.

As shown in FIGS. 1 and 2, the main parts of this tripod type constant velocity universal joint 1 include an outer joint member 2, a tripod member 3 as an inner joint member, and a roller unit 4 as a torque transmission member. has been done. The outer joint member 2 has a cup shape with one end open, and three linear track grooves 5 extending in the axial direction are formed on the inner peripheral surface at equal intervals in the circumferential direction. Each track groove 5 is provided with a roller guide surface 6 that is arranged to face each other in the circumferential direction of the outer joint member 2 and extends in the axial direction. A tripod member 3 and a roller unit 4 are housed inside the outer joint member 2.

The tripod member 3 includes a body part 31 (trunnion body part) having a center hole 30, and three leg shafts 32 (trunnion journals) that protrude in the radial direction from three equal parts in the circumferential direction of the outer peripheral surface of the body part 31. ), and an intermediate portion 33 that connects the outer circumferential surface of the trunk portion 31 and the outer circumferential surface of the leg shaft 32. The tripod member 3 is coupled to the shaft 8 so that torque can be transmitted by fitting a male spline 81 formed on the shaft 8 as an axis into a female spline 34 formed in the center hole 30 of the trunnion body 31. Ru. One axial end face of the tripod member 3 is engaged with a shoulder portion 82 provided on the shaft 8, and the retaining ring 10 attached to the tip of the shaft 8 is engaged with the other axial end face of the tripod member 3. Then, the tripod member 3 is fixed to the shaft 8 in the axial direction.

The roller unit 4 includes an outer ring 11 that is an annular roller centered on the axis of the leg shaft 32, and an annular inner ring 12 that is disposed on the inner diameter side of the outer ring 11 and fitted onto the leg shaft 32. and a large number of needle rollers 13 interposed between the outer ring 11 and the inner ring 12. The roller unit 4 is accommodated in the track groove 5 of the outer joint member 2. The roller unit 4 consisting of the outer ring 11, the inner ring 12, and the needle rollers 13 has a structure in which they are not separated by

washers

14 and 15.

In this embodiment, the outer peripheral surface 11a (see FIG. 2) of the outer ring 11 is a convex curved surface whose generatrix is an arc having a center of curvature on the axis of the leg shaft 32. The outer peripheral surface 11a of the outer ring 11 is in angular contact with the roller guide surface 6.

The needle rollers 13 have the cylindrical inner circumferential surface of the outer ring 11 as an outer raceway surface, the cylindrical outer circumferential surface of the inner ring 12 as an inner raceway surface, and can freely roll between these outer raceway surfaces and inner raceway surfaces. will be placed in The needle rollers 13 are arranged in a full roller state without a cage.

The outer peripheral surface of each leg shaft 32 of the tripod member 3 has a straight shape in the axial direction of the leg shaft 32 in a cross section (longitudinal section) in an arbitrary direction including the axis of the leg shaft 32. Further, as shown in FIG. 3, the outer peripheral surface of the leg shaft 32 has a substantially elliptical shape in a cross section (transverse section) perpendicular to the axis of the leg shaft 32. The outer peripheral surface of the leg shaft 32 contacts the inner peripheral surface 12a of the inner ring 12 in a direction perpendicular to the axial direction, that is, in the direction of the long axis a. In the axial direction, that is, in the direction of the short axis b, a gap m is formed between the outer peripheral surface of the leg shaft 32 and the inner peripheral surface 12a of the inner ring 12.

As shown in FIGS. 1 and 2, the intermediate portion 33 between the body 31 and the leg shaft 32 of the tripod member 3 is formed to draw a concave curve such as a circular arc in an arbitrary cross section including the axis of the leg shaft 32. be done. Both ends of the concave curve are smoothly connected to the outer circumferential surface of the trunk portion 31 and the outer circumferential surface of the leg shaft 32 so as to have a common tangent.

The inner circumferential surface 12a of the inner ring 12 has a convex arc shape in any cross section including the axis of the inner ring 12. Because of this and because the cross-sectional shape of the leg shaft 32 is approximately elliptical as described above, and a predetermined gap m is provided between the leg shaft 32 and the inner ring 12, the inner ring 12 It becomes possible to swing with respect to 32. As mentioned above, since the inner ring 12 and the outer ring 11 are assembled so as to be relatively rotatable via the needle rollers 13, the outer ring 11 can swing together with the inner ring 12 with respect to the leg shaft 32. It is. That is, the axes of the outer ring 11 and the inner ring 12 can be inclined with respect to the axis of the leg shaft 32 within a plane including the axis of the leg shaft 32 (see FIG. 4).

As shown in FIG. 4, when the tripod type constant velocity universal joint 1 rotates at an operating angle, the axis of the tripod member 3 is inclined with respect to the axis of the outer joint member 2, but the roller unit 4 is swingable. Therefore, it is possible to avoid a situation where the outer ring 11 and the roller guide surface 6 are obliquely crossed. As a result, the outer ring 11 rolls horizontally with respect to the roller guide surface 6, so that induced thrust and sliding resistance can be reduced, and the vibration of the tripod type constant velocity universal joint 1 can be reduced. can.

Furthermore, as already mentioned, the leg shaft 32 has a substantially elliptical cross section (cross section), and the inner circumferential surface 12a of the inner ring 12 has an arcuate convex cross section (vertical cross section). The outer circumferential surface of the leg shaft 32 and the inner circumferential surface 12a of the inner ring 12 are in contact with each other in point contact or in a narrow area close to point contact. Therefore, the force that tends to tilt the roller unit 4 is reduced, and the stability of the posture of the outer ring 11 is improved.

The tripod member 3 described above is manufactured from steel material through the main steps of forging (cold forging) → machining (turning) → broaching of the spline 34 → heat treatment → grinding of the outer peripheral surface of the leg shaft 32. It is manufactured after The outer peripheral surface of the leg shaft 32 can also be finished by cutting hardened steel instead of the grinding process. Moreover, a spheroidizing annealing process and a bonding process can be added before cold forging. If there is no problem with the forgeability during cold forging due to the use of a material with a low carbon content, the spheroidizing annealing step can be omitted. The heat treatment includes carburizing, quenching, and tempering.

FIG. 5 is a cross-sectional view showing the hardened layer 16 formed by heat treating the tripod member 3. The hardened layer 16 is formed by hardening the carburized layer by quenching. The hardened layer 16 is formed on the entire surface of the tripod member 3 including the outer circumferential surface of the leg shaft 32, the outer circumferential surface of the trunk portion 31, the surface of the intermediate portion 33, and the surface of the female spline 34. In the tripod member 3 as a completed product, the outer circumferential surface of the leg shaft 32 is finished by grinding (or hardened steel cutting), so the depth H of the hardened layer 16 on the outer circumferential surface of the leg shaft 32 is smaller than that in other areas. It is shallow by the amount of machining allowance due to grinding, etc. Note that since this machining allowance is usually small, about 0.1 mm, the thickness of the hardened layer 16 is drawn uniformly over the entire surface in FIG.

Hereinafter, in order to explain the characteristic parts of the present invention, the prerequisite configuration of each part of the tripod member 3 will be explained based on FIGS. 6 to 11. 6 is a front view of the tripod member 3 viewed in the axial direction from the opening side of the outer joint member 2, and FIG. 7 is a sectional view taken along the line MM in FIG. FIG. 8 is a cross-sectional view of the tripod member in which the shaft is inserted into the inner periphery, taken along line XX in FIG. Moreover, FIG. 9 is a planar development of the spline fitting portion viewed from the radial direction. 10 is a sectional view taken along line XX in FIG. 6, and FIG. 11 is a sectional view taken along line YY in FIG. In addition, in FIG. 8, the male spline 81 of the shaft 8 is represented by a broken line. Further, reference numeral 81a in FIG. 8 indicates the bottom of the male spline 81.

As shown in FIG. 7, one end of the tripod member 3 in the axial direction, specifically, the end that is the inlet side when inserting the shaft 8 into the inner circumference of the tripod member 3 (in this embodiment, the outer joint On the inner circumferential surface of the opening side end (see FIG. 1) of the member 2, a hollow portion 36 is formed in which peaks and valleys are arranged alternately in the circumferential direction. The hollow portion 36 is formed by removing the inner diameter side region of each small diameter portion of the female spline 34, thereby reducing the tooth height of each small diameter portion. The circumferential phase of the peak portion of the bulge portion 36 and the small diameter portion of the female spline 34 is equal, and the circumferential phase of the trough portion of the bulge portion 36 and the large diameter portion of the female spline 34 is also equal. The valley portion of the hollow portion 36 has the same radial dimension as the tooth bottom 34a of the female spline 34.

The hollow portion 36 includes a parallel portion 36a in which the tooth tips of the crests are parallel to the joint axis direction, and a tapered portion 36b formed on the back side of the parallel portion 36a, with the inner diameter of the crest gradually decreasing toward the back. Equipped with The tip of the tooth at the peak of the tapered portion 36b is connected to the tip of the small diameter portion of the female spline 34 via an edge-like corner P. The valley portion of the hollow portion 36 opens into a chamfer 37 formed on the inner circumferential surface of one axial end portion of the tripod member 3.

FIG. 8 is a sectional view showing a state in which a male spline 81 (indicated by broken lines) provided on the outer periphery of the shaft 8 is fitted into a female spline 34 provided on the inner periphery of the tripod member 3. As shown in FIG. 8, when the female spline 34 and the male spline 81 are in a fitted state, the parallel portion 36a of the padded portion 36 becomes a region where the male spline 81 is not fitted. On the other hand, in the tapered portion 36b, a partial region in the axial direction is fitted with the male spline 81.

As shown in FIG. 8, there is an edge-shaped angle between the back end of the tapered part 36, that is, the back end of the tapered part 36b, and the small diameter part of the female spline 34. Part P is formed. Due to the presence of this corner P, an edge load is generated between the tooth surface of the mating partner and the tooth surface during torque transmission.

In order to suppress backlash in the circumferential direction at the spline fitting portion, either the female spline 34 or the male spline 81 has spline teeth inclined with respect to the axial direction, as shown in FIG. (FIG. 9 shows an example in which the male spline 81 is a torsion spline). By press-fitting one spline consisting of a torsion spline into the other spline having straight spline teeth in the axial direction, the tripod member 3 and the shaft 8 can generate torque while suppressing the clearance (backlash) between them. communicatively coupled. At this time, the corner portion P comes into strong pressure contact with the tooth surface of the male spline 81 according to the press-fitting interference, so that the edge load during torque transmission becomes even larger.

As shown in FIGS. 10 and 11, the outer circumferential surface of the tripod member 3, specifically, the outer circumferential surface of the trunk portion 31 (including the intermediate portion 33; the same applies hereinafter) forms a circle centered on the axis of the leg shaft 32. An axis that extends in the tangential direction of In any direction cross section (YY cross section in FIG. 6), from both ends of the tripod member 3 in the axial direction to a plane R including the axis of each leg shaft 32 (hereinafter referred to as "leg shaft center plane R"). It has a profile that gradually expands in diameter. Comparing the XX cross section and the YY cross section at the same axial position, the thickness of the tripod member 3 in the radial direction is thinner in the XX cross section than in the YY cross section. In addition, at the same axial position of the tripod member 3, on the XX section in the circumferential direction of the tripod member 3, the wall thickness t in the radial direction of the tripod member 3 (starting from the bottom 34a of the female spline 34) wall thickness (see Figure 5) is the thinnest. This relationship holds throughout the entire tripod member 3 in the axial direction.

In addition, in the XX cross section shown in FIG. 10, the outline of the outer circumferential surface of the tripod member 3 is linear at least in a region including the outer diameter side of the back end (corner P) of the hollow part 36. . This is to prevent the roller unit 4, which is inclined in the axial direction with respect to the leg shaft 32, from interfering with the outer circumferential surface of the trunk section 31. On the other hand, in the YY cross section shown in FIG. 11, since the roller unit 4 does not come into contact with the outer peripheral surface of the trunk 31, the outline of the outer peripheral surface of the trunk 31 is shaped like a convex arc or is a combination of multiple arcs with different radii of curvature. It is formed in a convex curved shape.

In this way, in the double roller type tripod type constant velocity universal joint, edge load occurs at the boundary (corner P) between the female spline 34 and the slotted part 36 provided on the tripod member 3, and by using a torsion spline. Due to the fact that the edge rollers at the corner P further increase and the thinnest part of the tripod member 3 exists on the XX cross section, when the tripod type constant velocity universal joint 1 is used for a long period of time, metal fatigue may occur. It was necessary to ensure fatigue strength starting from the bottom of the female spline (point Q), which is located at the same axial position as the corner P on the XX cross section. Since the XX cross section is generally the weakest plane, there was room for improvement in the fatigue strength of the tripod member 3.

On the other hand, in the present embodiment, as shown in FIG. Let B be the axial distance from the end face to the back end (corner P) of the cutout part 36, and the radial direction of the tripod member 3 at the back end (corner P) of the cutout part 36 on the XX cross section. Assuming that the wall thickness (thickness from the tooth bottom 34a of the female spline 34) is C, and the diameter dimension of the tooth bottom 34a of the female spline 34 is D, B/A>0.28 and C/D>0.23. It is set.

When B/A<0.28, the axial length of the hollow portion 36 becomes relatively short. In this case, since the point P and furthermore the point Q are shifted to one side in the axial direction of the tripod member 3, the thickness of the tripod member 3 in the radial direction at the Q point becomes thinner. If B/A>0.28, the wall thickness of the tripod member 3 in the radial direction at the Q point becomes sufficiently thick, suppressing the lack of fatigue strength starting at the Q point, and reducing the repeated fatigue of the tripod member 3. Strength can be increased. Note that if the value of B/A is too large, the fitting length between the female spline 34 and the male spline 81 will be shortened and the contact pressure between the tooth surfaces will increase, which may accelerate wear on the tooth surfaces. . Therefore, to avoid this problem, it is preferable to set B/A<0.50.

If the thickness of the tripod member 3 in the radial direction satisfies C/D>0.23, the repeated fatigue strength of the tripod member 3 can be increased. That is, by setting B/A>0.28, it is possible to achieve C/D>0.23, and the cyclic fatigue strength of the tripod member 3 can be increased.

The embodiments of the present invention described above can also be applied to double roller type tripod constant velocity universal joints having other configurations.

For example, as shown in FIG. 12, the outer circumferential surface of the leg shaft 32 may be formed into a convexly curved surface (for example, a convex arc shape in longitudinal section), and the inner circumferential surface 12a of the inner ring 12 may be formed into a cylindrical surface. In this case as well, the axial distance from the end surface of the tripod member 3 on one side in the axial direction to the leg shaft center plane R is defined as A, and the distance from the end surface of the tripod member 3 on the one side in the axial direction to the back end (corner P) is the axial distance from the tooth bottom 34a of the female spline 34, and the radial wall thickness of the tripod member 3 at the back end (corner P) of the hollow part 36 on the By setting B/A > 0.28 and C/D > 0.23, the fatigue strength of the tripod member 3 is can be increased.

Alternatively, the outer circumferential surface of the leg shaft 32 may be formed into a convex curved surface (for example, a convex arc-shaped cross section), and the inner circumferential surface 12a of the inner ring 12 may be formed into a concave spherical surface that fits with the outer circumferential surface of the leg shaft. At this time, the

washers

14 and 15 can be made unnecessary by providing flanges at both ends of the inner diameter of the outer ring.

The tripod type constant velocity universal joint 1 described above is not limited to application to drive shafts of automobiles, but can be widely used in power transmission paths of automobiles, industrial equipment, etc.

1 Tripod type constant velocity universal joint 2 Outer joint member 3 Tripod member 4 Roller unit 5 Track groove 6 Roller guide surface 8 Axis (shaft)
11 Roller (outer ring)
12 Inner ring 13 Needle roller 16 Hardened layer 30 Center hole 31 Trunk 32 Leg shaft 33 Intermediate portion 34 Female spline 34a Tooth bottom P Back end (corner)

Claims

an outer joint member including track grooves extending in the axial direction at three locations in the circumferential direction, and each track groove having a pair of roller guide surfaces disposed opposite to each other in the circumferential direction;
a body portion having a female spline on the inner periphery; three leg shafts protruding in the radial direction of the body portion; and a body portion located between the body portion and the leg shafts, the cross section including the axis of the leg shafts having a concave curved shape. a tripod member comprising an intermediate portion forming a shape;
a roller attached to each leg shaft;
an inner ring that is fitted onto the leg shaft and rotatably supports the roller;
A tripod type constant velocity universal joint in which the roller is movable in the axial direction along the roller guide surface, and a roller unit including the roller and the inner ring is swingable with respect to the leg shaft,
A hollow part with a reduced tooth height of the female spline is provided on the inner periphery of one end in the axial direction of the tripod member,
Let A be the axial distance from one axial end face of the tripod member to a plane containing the axis of each leg shaft, and let B be the axial distance from the end face of the tripod member to the back end of the slotted part. and the radial direction of the tripod member at the back end of the hollow part extends in the tangential direction of a circle centered on the axis of the leg shaft, and on the axial cross section including the joint axis and the intermediate part. The wall thickness is C, the diameter of the tooth bottom of the female spline is D,
A tripod type constant velocity universal joint characterized by setting B/A>0.28 and C/D>0.23.
2. The tripod member according to claim 1, wherein, on the axial cross section of the tripod member, the outer circumferential surface of the tripod member has a contour whose diameter gradually increases from the end surface of the tripod member toward a plane including the axis of each leg shaft. The tripod type constant velocity universal joint described.
The tripod type constant velocity universal joint according to claim 2, wherein the contour is formed linearly in a region including an outer diameter side of the inner end of the hollow portion.
The inner peripheral surface of the inner ring has a convex arc shape in a longitudinal section of the inner ring, and the outer peripheral surface of the leg shaft has a straight shape in a longitudinal section including the axis of the leg shaft, and The outer peripheral surface of the leg shaft contacts the inner peripheral surface of the inner ring in the direction perpendicular to the axial direction, and the inner peripheral surface of the inner ring in the axial direction. The tripod type constant velocity universal joint according to any one of claims 1 to 3, wherein a gap is provided between the tripod type constant velocity universal joint.