Tripod type constant-velocity universal joint

Abstract

To provide a tripod type constant-velocity universal joint capable of obtaining a stable rotation while avoiding a situation of entering a pressure-contact state on a width surface (axial end surface) of an inner ring in a roller cassette.SOLUTION: A tripod type constant-velocity universal joint includes a roller cassette externally fitted to a leg shaft. The roller cassette includes an inner ring externally fitted to the leg shaft, a roller rotatably fitted with a guide surface of an outside joint member, and a rolling element interposed between the inner ring and the roller. A pair of ring bodies that regulate movement in an axial direction of the inner ring and the rolling element are disposed on both end sides in an axial direction of the roller cassette. The ring bodies are attached to the roller so as to enter a non pressure-contact state with respect to the inner ring and the rolling element.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a tripod-type constant velocity universal joint. [Background technology]

[0002] In driveshafts used in automotive power transmission systems, a sliding-type constant velocity universal joint is often provided on the inboard side (the center side in the vehicle width direction) and a fixed-type constant velocity universal joint is provided on the outboard side (the outside side in the vehicle width direction).The sliding-type constant velocity universal joint here allows both angular displacement and relative axial movement between the two shafts, while the fixed-type constant velocity universal joint allows angular displacement between the two shafts but does not allow relative axial movement between the two shafts.

[0003] A tripod constant velocity universal joint is known as a sliding type constant velocity universal joint. This tripod constant velocity universal joint is available in single roller and double roller types. A single roller type tripod constant velocity universal joint has rollers inserted into track grooves of an outer joint member rotatably attached to the trunnions of the tripod members via a plurality of needle rollers. A double roller type tripod constant velocity universal joint, as shown in FIGS. 11 and 12 , has rollers 111 disposed in track grooves 105 of an outer joint member 102, and an inner ring 112 fitted onto the trunnions 132 of a tripod member 103 to rotatably support the rollers 111 (see, for example, Patent Document 1).

[0004] 13, in a double roller type tripod constant velocity universal joint, needle rollers 117 and inner ring 112 are prevented from coming off by a pair of ring bodies (snap rings) 140, 140 attached to the inner circumferential surface of roller 111. In other words, circumferential grooves 141, 141 are provided at the axial end of inner circumferential surface 111b of roller 111, and the snap rings 140, 140 are attached to roller (outer ring) 111 by fitting the outer periphery of the snap ring 140 into these circumferential grooves 141, 141.

[0005] With the outer ring 111, inner ring 112, and needle rollers 117 assembled, the snap ring 140 is attached to the recessed circumferential groove (attachment groove) 141 on the inner surface 111b of the outer ring 111 by applying a radial contraction force to the snap ring 140 in the direction of arrow Y1 using a jig 150 placed on the end surface 111c of the outer ring 111, as shown in Figure 14, while applying an axial pressing force F to the snap ring 140 using an actuator or the like.

[0006] 14, the snap ring 140 elastically contracts in diameter in the direction of arrow Y1 and deforms into a spiral shape until the outer diameter dimension D of the snap ring 140 (the diameter dimension in a natural state where no external force is applied) becomes equal to or smaller than the inner diameter dimension d of the outer ring 111. In this state, the snap ring 140 is attached to the attachment groove 141 by inserting the snap ring 140 into the inner periphery of the outer ring 111. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2023-103794 Summary of the Invention [Problem to be solved by the invention]

[0008] When the snap ring 140 is attached using the method shown in Figure 14, the opposing surface 140a corresponding to the inner ring 112 and needle roller 113 side is plastically deformed by the pressure F to reduce the diameter, so that the opposing surface 140a becomes a surface that slopes inward in the axial direction of the trunnion 132 from the outer diameter side to the inner diameter side (see Figure 15).

[0009] Therefore, after assembly, as shown in Fig. 16, the opposing surfaces 140a are pressed against the inner ring 112 and the needle rollers 113. In other words, they are sandwiched between the pair of snap rings 140, making it impossible to achieve smooth rotation.

[0010] Therefore, a tripod-type constant velocity universal joint is provided that can avoid pressure contact with the width surface (axial end surface) of the inner ring in the roller cassette and can achieve stable rotation. [Means for solving the problem]

[0011] The tripod type constant velocity universal joint of the present invention comprises an outer joint member having three track grooves formed on its inner peripheral surface extending in the joint axial direction, each track groove being provided with a pair of roller guideways opposing in the joint circumferential direction, a tripod member arranged on the inner periphery of the outer joint member and having three trunnions protruding in the joint radial direction toward the track grooves, and a roller cassette fitted onto the trunnions, wherein the roller cassette comprises an inner ring fitted onto the trunnions, rollers fitted onto the guide surfaces so as to be rollable in the guide surfaces, and rolling elements interposed between the inner ring and the rollers, and a pair of ring bodies are arranged on both axial ends of the roller cassette to restrict axial movement of the inner ring and the rolling elements, and the ring bodies are attached to the rollers so as not to be in pressure contact with the inner ring and the rolling elements. Here, the non-pressure contact state refers to a state in which no pressure is applied to the counterpart, and refers to contact in which a gap is formed with respect to the counterpart and no pressure is applied to the counterpart.

[0012] Therefore, the pair of ring bodies that restrict the axial movement of the inner ring and rolling elements are not in pressure contact with the inner ring and rolling elements, and do not hinder the rotation of the inner ring and rolling elements.

[0013] Even if the surface of the ring body facing the inner ring or rolling elements is parallel to a plane perpendicular to the axis of the roller cassette, resulting in the non-pressure contact, the surface of the ring body facing the inner ring or rolling elements may be tapered from the outer diameter side to the inner diameter side, moving away from the inner ring or rolling elements, resulting in the non-pressure contact. In particular, if the surface is tapered, a gap is formed between the inner ring or rolling elements and the facing surface of the ring body, and this gap forms a path for lubricating oil to flow, improving the grease lubrication within the roller cassette.

[0014] The ring body is provided at the axial end of the inner surface of the roller, and its outer diameter portion is fitted into a circumferential groove that opens toward the inner diameter side of the cassette, so that it can be fitted into the circumferential groove in a reduced diameter state.After fitting, the reduced diameter state is released and the fitted state is maintained, and the ring body is given an inclination tendency in a direction that approaches the inner ring or rolling element side from the outer diameter side toward the inner diameter side.Even in a state in which the inclination tendency is given, the ring body may be in a non-pressure-contact state with the inner ring and the rolling element when its outer diameter portion is fitted into the circumferential groove.

[0015] The ring body may be configured as an inclined body that, in a free state, moves from the outer diameter side toward the inner diameter side toward the inner ring or rolling body side, and is configured to be in the non-pressurized state when the ring body is fitted into the circumferential groove.

[0016] The ring body may be configured such that the thickness of the surface facing the inner ring or rolling element is changed so that it becomes a tapered surface that moves away from the inner ring or rolling element from the outer diameter side toward the inner diameter side, and so that the ring body is in the non-pressure-contact state when fitted into the circumferential groove.

[0017] It is preferable that the inner surface of the inner ring is formed into an arc-shaped convex surface in the longitudinal section of the ring, the outer surface of the trunnion is straight in the longitudinal section including the axis of the trunnion and is oval or elliptical in the cross section perpendicular to the axis of the trunnion, the outer surface of the trunnion abuts against the inner surface of the inner ring in a direction perpendicular to the axis of the joint, and a gap is formed between the outer surface of the trunnion and the inner surface of the inner ring in the axial direction of the joint, and the roller is tiltable within the track groove.

[0018] This configuration creates a gap between the trunnion and the inner link, allowing the inner ring to move in the axial direction of the trunnion and to oscillate freely relative to the trunnion. Furthermore, the inner ring and roller are united via the rolling elements so that they can rotate relative to each other, allowing the inner ring and roller to oscillate freely as a unit. Here, "oscillate" refers to the tilting of the axes of the inner ring and roller relative to the trunnion axis within a plane that includes the trunnion axis.

[0019] Needle rollers can be used as rolling elements, which allows the use of full complement needle rollers without a cage. [Effects of the Invention]

[0020] The present invention prevents the snap ring from pinching the width surface (axial end surface) of the inner ring, allowing the roller cassette to rotate smoothly and effectively preventing an increase in rotational resistance. Furthermore, when the snap ring is not pressed against the inner ring and rolling elements, a gap may be formed between the inner ring or rolling elements and the opposing surface of the ring body. If such a gap is formed, a path for lubricating oil to flow is formed, improving the grease lubrication within the roller cassette. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a cross-sectional view of a tripod type constant velocity universal joint according to the present invention in the joint axial direction. [Figure 2] FIG. 2 is a cross-sectional view taken along the line KK in FIG. [Figure 3] FIG. 2 is a simplified cross-sectional view of a roller cassette. [Figure 4] FIG. 2 is a plan view of a snap ring, which is a ring body, in a free state. [Figure 5] FIG. 4 is an enlarged cross-sectional view of a main part of the snap ring in a free state. [Figure 6] FIG. 2 is an enlarged cross-sectional view of a roller cassette. [Figure 7] FIG. [Figure 8] FIG. 2 is an enlarged cross-sectional view of a main part of the roller cassette. [Figure 9] FIG. 10 is an enlarged cross-sectional view of a main portion of a roller cassette having another type of snap ring. [Figure 10] FIG. 10 is an enlarged cross-sectional view of a main portion of another snap ring in a free state. [Figure 11] FIG. 1 is a cross-sectional view of a conventional tripod-type constant velocity universal joint taken in the joint axial direction. [Figure 12] FIG. 12 is a partial cross-sectional view taken along line KK in FIG. [Figure 13] FIG. 2 is an enlarged cross-sectional view of a main part of the roller cassette. [Figure 14] FIG. [Figure 15] FIG. 4 is an enlarged cross-sectional view of a main portion of the snap ring in a plastically deformed state. [Figure 16] 10 is an enlarged cross-sectional view of a main portion of the roller cassette in a state in which the snap ring is in pressure contact or contact with the inner ring. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0022] The tripod type constant velocity universal joint 1 of this embodiment shown in Figures 1 to 4 is of a double roller type. Note that Figure 1 is an axial cross-sectional view of the double roller type tripod type constant velocity universal joint, and Figure 2 is a cross-sectional view taken along line KK in Figure 1. Note that in the following description, the joint axial direction and joint circumferential direction respectively refer to the axial direction and circumferential direction of the tripod type constant velocity universal joint when the operating angle is set to 0°.

[0023] As shown in Figures 1 and 2, the tripod type constant velocity universal joint 1 is mainly composed of an outer joint member 2, a tripod member 3 as an inner joint member, and a roller unit 4 as a torque transmission member. The outer joint member 2 is cup-shaped with one end open, and has three linear track grooves 5 extending in the joint axial direction formed on its inner peripheral surface at equal intervals in the joint circumferential direction. Each track groove 5 is formed with a roller guide surface 6 that is arranged opposite to each other in the joint circumferential direction of the outer joint member 2 and extends in the joint axial direction. The tripod member 3 and the roller unit 4 are housed inside the outer joint member 2.

[0024] The tripod member 3 integrally comprises a body 31 (trunnion body) having a central hole 30, and three trunnion journals 32 protruding radially from positions equally dividing the joint circumferential direction on the outer peripheral surface of the body 31. The tripod member 3 is coupled to the shaft 8 as an axis so as to be able to transmit torque by fitting a male spline formed on the shaft 8 as an axis into a female spline 34 formed in the central hole 30 of the body 31.

[0025] The roller unit 4 is mainly composed of an outer ring 11, which is an annular roller centered on the axis of the trunnion 32, an annular inner ring 12 arranged on the inner diameter side of the outer ring 11 and fitted around the trunnion 32, and a large number of rolling elements 13 interposed between the outer ring 11 and the inner ring 12. In this embodiment, full-complement needle rollers without cages are used as an example of the rolling elements 13. The roller unit 4 is housed in the track grooves 5 of the outer joint member 2. As will be described in detail later, the roller unit 4, which is made up of the outer ring 11, inner ring 12, and needle rollers 13, is structured to not disassemble naturally by means of steel snap rings 14, 14.

[0026] In this embodiment, the outer peripheral surface of the outer ring 11 (see FIG. 2) is a convex curved surface whose generating line is an arc having a center of curvature on the axis of the trunnion 32. The outer peripheral surface of the outer ring 11 is in angular contact with the roller guideway 6.

[0027] The needle rollers 13 are arranged to roll freely between the cylindrical inner peripheral surface 11b (see Figure 6) of the outer ring 11 as an outer raceway surface and the cylindrical outer peripheral surface of the inner ring 12 as an inner raceway surface.

[0028] The outer peripheral surface of each trunnion 32 of the tripod member 3 has a straight shape in the axial direction of the trunnion 32 in a cross section in any direction including the axis of the trunnion 32. Also, as shown in FIG. 3, the outer peripheral surface of the trunnion 32 has a substantially elliptical shape in a cross section perpendicular to the axis of the trunnion 32. The outer peripheral surface of the trunnion 32 contacts the inner peripheral surface 12a of the inner ring 12 in a direction perpendicular to the joint axial direction, i.e., in the direction of the major axis a. In the joint axial direction, i.e., in the direction of the minor axis b, a gap m is formed between the outer peripheral surface of the trunnion 32 and the inner peripheral surface 12a of the inner ring 12.

[0029] The inner peripheral surface 12a of the inner ring 12 forms a convex arc shape in any cross section including the axis of the inner ring 12. Because of this, and because the cross section of the trunnion 32 is generally elliptical as described above and a predetermined gap m (see FIG. 3) is provided between the trunnion 32 and the inner ring 12, the inner ring 12 is able to swing relative to the trunnion 32. As described above, the inner ring 12 and the outer ring 11 are assembled via the needle rollers 13 so as to be relatively rotatable, and therefore the outer ring 11 can swing integrally with the inner ring 12 relative to the trunnion 32. In other words, the axes of the outer ring 11 and the inner ring 12 can tilt relative to the axis of the trunnion 32 within a plane including the axis of the trunnion 32.

[0030] When the tripod type constant velocity universal joint 1 rotates through an operating angle, the axis of the tripod member 3 is inclined relative to the axis of the outer joint member 2, but because the roller unit 4 is swingable, it is possible to prevent the outer ring 11 from intersecting the roller guideway 6 at an angle. As a result, the outer ring 11 rolls horizontally relative to the roller guideway 6, which reduces induced thrust and sliding resistance and enables the tripod type constant velocity universal joint 1 to achieve low vibration.

[0031] As already mentioned, the cross section (transverse section) of the trunnion 32 is substantially elliptical and the cross section (longitudinal section) of the inner peripheral surface 12a of the inner ring 12 is an arc-shaped convex cross section, so that the outer peripheral surface of the trunnion 32 on the torque load side and the inner peripheral surface 12a of the inner ring 12 come into point contact (including contact over a small area close to point contact) at contact point X, as shown in Figure 3. This reduces the force that tends to tilt the roller unit 4, improving the stability of the posture of the outer ring 11.

[0032] As shown in FIG. 4, the snap ring 14 is a non-endless ring having a cutout 14c in part thereof. Therefore, when the snap ring 14 is installed, as shown in FIG. 7, the snap ring 14 elastically contracts in diameter and deforms into a spiral shape until the outer diameter D of the snap ring 14 (the diameter in its natural state without external force) becomes equal to or smaller than the inner diameter d of the outer ring 11. In this state, a pressing force F is applied to the snap ring 14, and the snap ring 14 is inserted into the inner periphery of the outer ring 11, thereby installing the snap ring 14 in the circumferential groove (take-in groove) 15. Note that the notch end faces 14c1, 14c1 of the cutout 14c are inclined at a predetermined angle relative to the radial direction, and the notch width H in the free state is set arbitrarily. In this case, the inclination angle α of the notch end faces 14c1, 14c1 and the notch width H may be set to any value that allows the snap ring 14 to contract during installation and to deform so as to fit into the groove into which it is to be installed.

[0033] For this reason, snap ring 14 develops an inclination tendency inclining inward in the axial direction from the outer diameter direction to the inner diameter direction, as shown in Fig. 15. For this reason, snap ring 14 of the present invention is formed in advance, as shown in Fig. 5, so that in its free state it has an inclination shape in the opposite direction to the inclination tendency shown in Fig. 15. In other words, it is formed into an inclined shape that inclins outward in the axial direction from the outer diameter direction to the inner diameter direction. In other words, the shape shown in Fig. 5 can be called an inverted dish shape.

[0034] In this case, it is preferable to set the thickness (wall thickness) of the snap ring 14 as t and the amount of plastic deformation caused when the snap ring is installed in the roller cassette 4 as β so that the relationship shown in the following equation 1 is satisfied. The inclination angle θ of the opposing surface (axial inner surface) 14a with respect to the horizontal plane is, for example, about 0.6° to 4.2°.

number

[0035] The lower limit value in Equation 1, (t + 0.05) mm, is the value required to prevent pinching with the inner ring 12 (to ensure non-contact), and the upper limit value in Equation 1, (t + 0.20) mm, is the value required to hold the inner ring 12. Here, "holding" means restricting the inner ring 12 and needle rollers 13 from moving a specified amount in the axial direction, and enabling restriction without impairing the function of the snap ring 14. In other words, the distance should be such that the amount of axial movement of the inner ring 12 and needle rollers 13 does not become too large, causing rattles that could damage parts or increase noise.

[0036] In this case, the state shown in FIG. 8 or the state shown in FIG. 9 occurs. In the state shown in FIG. 8, the state is parallel to a plane perpendicular to the axial direction. In other words, the state is perpendicular to the axis of the roller cassette 4 and parallel to a plane M including the roller cassette axis center. In this case, the snap ring 14 is a clearance fit in the assembly groove 15, and minute gaps (for example, gaps of about 0.1 mm to 0.6 mm) are formed between the axial end faces (width faces) of the needle rollers 13 and the axial end faces of the inner ring 12 and the opposing surfaces 14a of the snap ring 14 and inner ring 12. Therefore, the ring body (snap ring 14) is not pressed against the inner ring 12 and rolling elements 13.

[0037] 9, the snap ring 14 has its opposing surface 14a inclined axially outward from the outer diameter side toward the inner diameter side with respect to a plane M that is perpendicular to the axis and includes the roller cassette axis center. In other words, it is in a so-called outward-opening state. Therefore, the ring body (snap ring 14) is not in pressure contact with the inner ring 12 and the rolling elements 13.

[0038] To attach the other snap ring 14, the roller cassette is turned upside down and the process shown in FIG. 7 is carried out.

[0039] In the tripod-type constant velocity universal joint according to the present invention, the pair of ring bodies 14 that restrict the axial movement of the inner ring 12 and the rolling elements 13 are not in pressure contact with the inner ring 12 and the rolling elements 13, and therefore do not hinder the rotation of the inner ring 12 and the rolling elements 13. In other words, it is possible to prevent the width faces (axial end faces) of the inner ring 12 from being pinched by the snap rings 14, allowing for smooth rotation of the roller cassette 4 and effectively preventing an increase in rotational resistance.

[0040] Furthermore, when the inner ring 12 and the rolling elements 13 are not in pressure contact, a gap may be formed between the inner ring 12 or the rolling elements 13 and the opposing surface of the ring element 14. If such a gap is formed, a path for the lubricating oil to flow is formed, improving the lubrication of the grease inside the roller cassette 4. In particular, as shown in Figure 9, a so-called outward opening state has the advantage that a path for the lubricating oil to flow is easily formed.

[0041] Furthermore, by providing a gap between the trunnion 32 and the inner link 12, the inner ring 12 can move in the axial direction of the trunnion 32, and is free to oscillate and swing relative to the trunnion 32. Furthermore, the inner ring 12 and rollers 11 are united via rolling elements so as to be relatively rotatable, and therefore the inner ring 12 and rollers 11 can oscillate and swing freely as a unit. Here, "oscillate" means that the axes of the inner ring 12 and rollers 11 tilt relative to the axis of the trunnion 32 within a plane including the axis of the trunnion 32.

[0042] The rolling elements can be needle rollers 13. This allows the use of full complement needle rollers without a cage.

[0043] 10 shows another embodiment of a snap ring, in which the snap ring in its free state does not have the inclined shape shown in FIG. 5, but rather the opposing surface 14a is an inclined surface that slopes outward in the axial direction from the outer diameter side to the inner diameter side. In other words, the thickness of the snap ring 14 gradually decreases from the outer diameter side to the inner diameter side.

[0044] In this case, even if the opposing surface 14a of the snap ring 14 tends to face axially inward from the outer diameter side to the inner diameter side due to assembly, the opposing surface 14a is an inclined surface that inclines axially outward from the outer diameter side to the inner diameter side, so the opposing surface 14a can be made to not come into pressure contact with the inner ring 12 and the rolling elements 13. Note that the inclination angle θ1 of the inclined surface 14a is preferably approximately the same as the inclination angle θ of the inclined-shaped body as shown in FIG.

[0045] The snap ring shown in Fig. 10 achieves the same effects as the snap ring 14 having an inclined shape as shown in Fig. 5. In the snap ring shown in Fig. 10, the wall thickness is smaller on the inner diameter side, which results in poor strength and rigidity, but this does not pose a problem because excessive external force is not applied to the snap ring 14.

[0046] Although the above describes an embodiment of the present invention, the present invention is not limited to the above embodiment and various modifications are possible. The inclination angle of the inclined-shaped body in a free state, as shown in FIG. 5, can be varied depending on the material, size, and thickness of the snap ring 14. That is, the inclination angle can be varied depending on the amount of inclination of the snap ring 14 when installed. Furthermore, the snap ring 14 forms a loose fit with the intake groove 15, but when installed, a force acts on the snap ring 14 to expand its diameter, so that its outer edge is pressed against the bottom of the installation groove 15 and does not rattle or slip out. Furthermore, the tripod-type constant velocity universal joint can be used in drive shafts installed in the torque transmission system of an automobile. However, the applications of constant velocity universal joints are not limited to automobiles and can, of course, be widely used in power transmission systems of automobiles and industrial equipment in general. [Explanation of symbols]

[0047] 2 Outer joint member 3 Tripod member 4 roller cassette 5 Straight track grooves 6 Roller guideway 11 Laura (Outering) 11b Inner surface 12 Inner Ring 12a Inner peripheral surface 12a 13 Rolling elements 14 Ring body (snap ring) 15 Circumferential groove (assembly groove) 32 Leg axis

Claims

1. a tripod-type constant velocity universal joint comprising: an outer joint member having three track grooves formed on an inner peripheral surface thereof, the track grooves extending in a joint axial direction, and a pair of roller guideways opposed in a joint circumferential direction, each track groove being provided with a pair of roller guideways; a tripod member disposed on an inner peripheral surface of the outer joint member and having three trunnions protruding in a joint radial direction toward the track grooves; and a roller cassette fitted onto the trunnions, the roller cassette comprising an inner ring fitted onto the trunnions, rollers fitted onto the guideways so as to be rollable, and rolling elements interposed between the inner ring and the rollers, a pair of ring bodies for restricting axial movement of the inner ring and the rolling elements are disposed on both axial ends of the roller cassette; 10. A tripod-type constant velocity universal joint, wherein the ring body is attached to the roller so as not to be in pressure contact with the inner ring and the rolling elements.

2. 2. The tripod-type constant velocity universal joint according to claim 1, wherein the surface of said ring body facing the inner ring or rolling element is parallel to a plane perpendicular to the axis of the roller cassette, thereby forming said non-pressure-contact state.

3. 2. The tripod-type constant velocity universal joint according to claim 1, characterized in that the surface of the ring body facing the inner ring or rolling element is a tapered surface that moves away from the inner ring or rolling element from the outer diameter side to the inner diameter side, thereby forming the non-pressure-welded shape.

4. The tripod-type constant velocity universal joint according to claim 1, characterized in that the ring body is provided at the axial end of the inner surface of the roller, and its outer diameter portion is fitted into a circumferential groove that opens toward the cassette inner diameter side, and can be fitted into the circumferential groove in a reduced diameter state, and after fitting, the reduced diameter state is released and the fitted state is maintained, and the ring body is given an inclination tendency in a direction approaching the inner ring or rolling element side from the outer diameter side toward the inner diameter side, and even in a state in which the inclination tendency is given, the ring body is not in a pressure-contact state with the inner ring and the rolling element even when the outer diameter portion is fitted into the circumferential groove.

5. The tripod-type constant velocity universal joint according to claim 4, characterized in that the ring body is an inclined-shaped body that, in a free state, moves from the outer diameter side to the inner diameter side and away from the inner ring or rolling element side, and is configured so as to be in the non-pressure-contact state when the ring body is fitted into the circumferential groove.

6. The tripod-type constant velocity universal joint according to claim 4, characterized in that the thickness of the ring body is changed so that the surface facing the inner ring or rolling element becomes a tapered surface that moves away from the inner ring or rolling element from the outer diameter side toward the inner diameter side, and the ring body is configured to be in the non-pressure-fit state when fitted into the circumferential groove.

7. 2. The tripod-type constant velocity universal joint according to claim 1, wherein the inner peripheral surface of the inner ring is formed into an arc-shaped convex surface in a ring longitudinal section, the outer peripheral surface of the trunnion is straight in a longitudinal section including the axis of the trunnion and is oval or elliptical in a cross section perpendicular to the axis of the trunnion, the outer peripheral surface of the trunnion abuts against the inner peripheral surface of the inner ring in a direction perpendicular to the axis of the joint, and a gap is formed between the outer peripheral surface of the trunnion and the inner peripheral surface of the inner ring in the axial direction of the joint, and the rollers are tiltable in the track grooves.

8. 2. The tripod type constant velocity universal joint according to claim 1, wherein the rolling elements are needle rollers.

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