Tripod type constant velocity universal joint

Abstract

In a double-roller type tripod-type constant velocity universal joint, the rolling resistance of the rollers is reduced, resulting in low vibration. [Solution] This tripod-type constant velocity universal joint comprises an outer joint member having track grooves extending axially at three locations in the circumferential direction, each track groove having a pair of roller guide surfaces arranged opposite each other in the circumferential direction, a tripod member having three leg shafts projecting radially, a roller inserted into the track groove, and an inner ring fitted onto the leg shafts to rotatably support the roller, and is configured so that the roller can move in the axial direction of the outer joint member along the roller guide surface. On the outer circumferential surface of the roller, cylindrical portions are provided on both sides of the center in the width direction of the roller, and recesses are provided between the cylindrical portions that are recessed from the outer circumferential surface of the cylindrical portions, and flat portions are provided on both sides of the center in the width direction of the roller on the roller guide surface, and protrusions are provided between the flat portions that project from the end faces of the flat portions and engage with the recesses.

Description

Technical Field

[0001] The present invention relates to a tripod constant velocity joint.

Background Art

[0002] In a drive shaft used in an automotive power transmission system, a sliding constant velocity joint is often connected to the inboard side (center side in the vehicle width direction) of an intermediate shaft, and a fixed constant velocity joint is connected to the outboard side (end side in the vehicle width direction). The sliding constant velocity joint mentioned here allows both angular displacement and axial relative movement between two shafts, while the fixed constant velocity joint allows angular displacement between two shafts but does not allow axial relative movement between the two shafts.

[0003] The tripod constant velocity joint is known as a sliding constant velocity joint. As this tripod constant velocity joint, there are a single roller type and a double roller type. An example of the double roller type tripod constant velocity joint is described in, for example, Patent Document 1 and Patent Document 2. The double roller type tripod constant velocity joint includes a roller inserted into a track groove of an outer joint member and an inner ring that fits over a leg shaft of a tripod member and rotatably supports the roller. Compared with the single roller type, it has the advantage of achieving reduction of induced thrust (axial force induced by friction between parts inside the joint) and slide resistance.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] In conventional double-roller tripod-type constant velocity universal joints, the outer surface of the roller is roughly spherical or ring-shaped, and the roller guide surface (rolling surface of the roller) of the outer ring's track groove has a circular contact shape with a contact ratio that follows the shape of the roller's outer diameter, or an angular contact shape with a contact ratio and contact angle.

[0006] Therefore, due to its structure, when the tripod-type constant velocity universal joint rotates at an operating angle, the unit 104 (roller unit), which includes the roller 111 and the inner ring 112, may tilt to the left or right on a cross section perpendicular to the joint axis direction, as shown in Figure 13, or it may tilt to the front or back on a cross section parallel to the joint axis direction, as shown in Figure 14.

[0007] When tilting occurs from side to side or front to back, the direction of travel of the roller 111 may differ from the orientation of the roller 111, or the outer diameter end face 111a of the roller 111 may come into contact with the bottom of the track groove 105, or the outer circumference of the roller 111 may come into contact with the unloaded roller guide surface 106' of the track groove 105 (the direction of rotation is indicated by arrows in Figure 13). This increases rolling resistance, and the induced force and sliding resistance of the constant velocity universal joint increase. All of these factors worsen the NVH characteristics of the automobile.

[0008] Furthermore, in the case of circular contact or angular contact shapes, when the torque applied to the coupling becomes unloaded (or nearly unloaded) during high-speed rotation, the centrifugal force pushes the roller 111 toward the outer diameter side. As shown in Figure 15, a wedge effect occurs at the wedge angle between the roller 111 and the roller guide surface 106, causing the roller 111 and the roller guide surface 106 to bite together, which raises concerns about increased rolling resistance.

[0009] As shown in Patent Document 2, some rollers have a cylindrical outer surface to suppress lateral tilting, but since they do not have a mechanism to suppress front-to-back tilting, front-to-back tilting is more likely to occur, which can actually increase rolling resistance.

[0010] Therefore, the present invention aims to reduce the rolling resistance of the rollers and reduce vibration in a double-roller type tripod-type constant velocity universal joint. [Means for solving the problem]

[0011] The first tripod-type constant velocity universal joint of the present invention comprises an outer joint member having track grooves extending axially at three locations in the circumferential direction, each track groove having a pair of roller guide surfaces arranged opposite to each other in the circumferential direction, a tripod member having three leg shafts projecting radially, a roller inserted into the track grooves, and an inner ring fitted onto the leg shafts and supporting the roller rotatably, wherein the roller is configured to move in the axial direction of the outer joint member along the roller guide surfaces, characterized in that cylindrical portions are provided on both sides of the outer circumferential surface of the roller, sandwiching the center in the width direction of the roller, and recesses are provided between the cylindrical portions, recesses that are recessed from the outer circumferential surface of the cylindrical portions, and flat portions are provided on both sides of the roller guide surface, sandwiching the center in the width direction of the roller, and protrusions are provided between the flat portions, protruding from the end faces of the flat portions and engaging with the recesses.

[0012] In the first tripod-type constant velocity universal joint described above, when a torque load is applied, the cylindrical portion of the roller and the flat surface portion of the outer joint member make line contact, thereby suppressing the lateral tilting phenomenon of the roller. Furthermore, as the roller rolls on the track of the outer joint member, the recess of the roller's outer diameter and the convex portion of the outer joint member come into contact, correcting the forward and backward tilt of the roller. In this case, when the roller rolls toward the outer diameter side of the outer joint member, the inner diameter side of the convex portion of the outer joint member comes into contact with the recess of the roller's outer diameter, and the frictional force acts as a brake, changing the direction of the roller, thus avoiding further contact and preventing an increase in rolling resistance. When the roller rolls in the opposite direction (i.e., toward the inner diameter of the outer joint member), the outer diameter side of the convex portion of the outer joint member comes into contact with the recess of the roller's outer diameter, changing the direction of the roller. This makes it possible to keep the roller horizontal to the track groove, preventing unnecessary contact between the roller and the outer joint member outside of the torque transmission points, and thus avoiding a further increase in rolling resistance.

[0013] The second tripod-type constant velocity universal joint of the present invention comprises an outer joint member having track grooves extending axially at three locations in the circumferential direction, each track groove having a pair of roller guide surfaces arranged opposite to each other in the circumferential direction, a tripod member having three leg shafts projecting radially, a roller inserted into the track grooves, and an inner ring fitted onto the leg shafts and supporting the roller rotatably, wherein the roller is configured to move in the axial direction of the outer joint member along the roller guide surfaces, characterized in that cylindrical portions are provided on both sides of the outer circumferential surface of the roller, sandwiching the widthwise center of the roller, and protrusions are provided between the cylindrical portions, protruding from the outer circumferential surface of the cylindrical portions, and flat portions are provided on both sides of the roller guide surface, sandwiching the widthwise center of the roller, and recesses are provided between the flat portions, recessed from the end faces of the flat portions, into which the protrusions engage.

[0014] In the second tripod-type constant velocity universal joint described above, when a torque load is applied, the cylindrical portion of the roller and the flat surface portion of the outer joint member make line contact, thereby suppressing the lateral tilting phenomenon of the roller. Furthermore, as the roller rolls on the track of the outer joint member, the convex portion of the roller's outer diameter contacts the concave portion of the outer joint member, thereby correcting the forward and backward tilt of the roller. In this case, when the direction of travel of the roller is toward the outer diameter side of the outer joint member, the outer diameter side of the convex portion of the roller's outer diameter contacts the concave portion of the outer joint member, changing the orientation of the roller, avoiding further contact, and preventing an increase in rolling resistance. When the roller rolls in the opposite direction (i.e., toward the inner diameter of the outer joint member), the inner diameter side of the convex portion of the roller's outer diameter contacts the concave portion of the outer joint member, changing the orientation of the roller. This makes it possible to keep the roller horizontal to the track groove, preventing unnecessary contact between the roller and the outer joint member outside of the torque transmission point, and preventing a further increase in rolling resistance.

[0015] In the above configuration, it is preferable that the contact angle between the side surface of the protrusion and the recess be 20° or more and 60° or less, and more preferably 35° or more and 45° or less. If the contact angle is less than 20°, when the roller moves towards the outer diameter side due to centrifugal force in an unloaded state, the non-loaded side also makes contact, and there is a concern that the rolling resistance of the roller will increase due to the occurrence of a wedge effect. If it exceeds 60°, the wedge effect is reduced, but the forging formability of the outer joint member deteriorates, and there is a concern that shape defects and a reduction in mold life may occur.

[0016] As a tripod-type constant velocity universal joint, it is also possible to use one in which the outer surface of the leg shaft is formed as a convex curved surface and the inner surface of the inner ring is formed as a cylindrical surface, or one in which the outer surface of the leg shaft is formed as a convex curved surface and the inner surface of the inner ring is formed as a concave curved surface.

[0017] In the above configuration, a guide surface for guiding the axially outer end face of the roller may be provided in the track groove of the outer joint member. When the axially outer end face of the roller contacts the guide surface, the restraining force against the attitude change of the roller increases. Therefore, for example, even when the gap between the convex portion and the concave portion is large, the forward and backward tilting of the roller can be suppressed. That is, the deterioration of the rolling resistance of the roller and the deterioration of NVH can be more stably suppressed. Further, by reducing the volume inside the outer joint member, the amount of lubricating grease contained therein can also be reduced, and the overall mass and cost can be reduced.

Advantages of the Invention

[0018] According to the present invention, in a double-roller type tripod constant velocity joint, it is possible to reduce the rolling resistance of the roller and achieve low vibration.

Brief Description of the Drawings

[0019] [Figure 1] It is a longitudinal sectional view of a first embodiment of a tripod constant velocity joint. [Figure 2] It is a partial cross-sectional view taken along the line K-K of FIG. 1 as viewed in the arrow direction. [Figure 3] It is a cross-sectional view taken along the line L-L of FIG. 1. [Figure 4] It is a longitudinal sectional view showing a state in which the tripod constant velocity joint of FIG. 1 takes an operating angle. [Figure 5] It is an enlarged cross-sectional view showing the contact portion between the outer ring and the roller guide surface of FIG. 2. [Figure 6] It is an enlarged cross-sectional view showing the main part of the contact portion between the outer ring and the roller guide surface of FIG. 5. [Figure 7] It is an enlarged cross-sectional view showing the contact portion between the outer ring and the roller guide surface of a tripod constant velocity joint of a second embodiment. [Figure 8] It is an enlarged cross-sectional view showing the contact portion between the outer ring and the roller guide surface when a guide surface is provided in the track groove of the outer joint member of FIG. 5. [Figure 9] It is a partially enlarged view showing another form of the guide surface. [Figure 10] It is an enlarged cross-sectional view showing the contact portion between the outlining showing different forms of the concave and convex portions in FIG. 5 and the roller guide surface. [Figure 11] It is a cross-sectional view of a tripod constant velocity joint according to another embodiment. [Figure 12] It is a cross-sectional view of a tripod constant velocity joint according to another embodiment. [Figure 13] It is a cross-sectional view of a tripod constant velocity joint explaining left and right tilts. [Figure 14] It is a longitudinal sectional view of a tripod constant velocity joint explaining front and rear tilts. [Figure 15] It is a cross-sectional view of a tripod constant velocity joint explaining the wedge angle.

Mode for Carrying Out the Invention

[0020] A first embodiment of the tripod constant velocity joint according to the present invention will be described based on FIGS. 1 to 6.

[0021] The tripod constant velocity joint 1 of this embodiment is of a double roller type. As shown in FIGS. 1 and 2, this tripod constant velocity joint 1 mainly includes 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 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. In each track groove 5, roller guide surfaces 6 extending in the axial direction of the outer joint member 2 are formed so as to face each other in the circumferential direction of the outer joint member 2. Inside the outer joint member 2, the tripod member 3 and the roller unit 4 are accommodated.

[0022] The tripod member 3 has three radially protruding leg shafts 7. The tripod member 3 is coupled to the shaft 9 in a torque-transmitting manner by fitting a male spline 24 formed on the shaft 9 into a female spline 23 formed in the central hole 8. The tripod member 3 is fixed axially to the shaft 9 by engaging a retaining ring 10 attached to the tip of the shaft 9 with the end face of the tripod member 3.

[0023] The roller unit 4 consists of an outer ring 11 which is a roller, and the inside of this outer ring 11 The main part consists of a cylindrical inner ring 12 positioned and fitted onto the leg shaft 7, and a number of needle-shaped rollers 13 interposed between the outer ring 11 and the inner ring 12, and is housed in the track groove 5 of the outer joint member 2.

[0024] The inner circumferential surface 12a of the inner ring 12 is convex, specifically, it is convex in the shape of a circular arc in the longitudinal cross-section including the axis of the inner ring 12. The roller unit 4, consisting of the inner ring 12, needle rollers 13, and outer ring 11, is designed to remain inseparable by washers 14 and 15.

[0025] The outer circumferential surface of each leg shaft 7 of the tripod member 3 is straight in a longitudinal cross-section that includes the axis OO of the leg shaft 7. Also, as shown in Figure 3, the outer circumferential surface of the leg shaft 7 is substantially elliptical in a cross-section perpendicular to the axis OO of the leg shaft 7. The outer circumferential surface of the leg shaft 7 is in contact with the inner circumferential surface 12a of the inner ring 12 in a direction perpendicular to the axis of the joint, i.e., in the direction of the major axis a. In the direction of the axial direction of the joint, i.e., in the direction of the minor axis b, a gap m is formed between the outer circumferential surface of the leg shaft 7 and the inner circumferential surface 12a of the inner ring 12.

[0026] The outer ring 11 of the roller unit 4, which is mounted on the leg shaft 7 of the tripod member 3, is rotatably supported by the inner ring 12 via needle rollers 13. When the tripod-type constant velocity universal joint 1 rotates at an operating angle, the outer ring 11 rolls on the roller guide surface 6 of the track groove 5 of the outer joint member 2. Since the cross-section of the leg shaft 7 is substantially elliptical, as shown in Figure 4, when the tripod-type constant velocity universal joint 1 takes 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 can be inclined with respect to the axis of the leg shaft 7 of the tripod member 3. Therefore, it is possible to avoid a state in which the outer ring 11 of the roller unit 4 and the roller guide surface 6 are obliquely aligned. As a result, the outer ring 11 rolls correctly with respect to the roller guide surface 6, which reduces induced thrust and sliding resistance, and enables low vibration of the joint.

[0027] As shown in an enlarged view in Figure 5, cylindrical portions 11a1 and 11a2 are formed on both sides of the outer circumferential surface of the outer ring 11, flanking the center PP in the width direction of the outer ring 11 (hereinafter referred to as the roller width direction). In the cross-section of Figure 5, the cylindrical portion 11a1 on the outer diameter side of the joint and the cylindrical portion 11a2 on the inner diameter side of the joint are symmetrical with respect to the center PP in the roller width direction.

[0028] Furthermore, on the outer circumferential surface of the outer ring 11, a recess 16 is provided between the cylindrical portions 11a1 and 11a2, which is recessed from the outer circumferential surfaces of the cylindrical portions 11a1 and 11a2. The recess 16 is continuously recessed in the circumferential direction. In this embodiment, as shown in Figure 6, the side portion 16a of the recess 16 is a tapered surface that narrows in width toward the bottom side of the recess 16, and its cross-section is trapezoidal. The recess 16 is symmetrical with respect to the center PP in the roller width direction.

[0029] As shown in Figure 5, the roller guide surface 6 has flat surface portions 6a1 and 6a2 formed on both sides of the center PP in the width direction (hereinafter referred to as the roller width direction) of the outer ring 11. In the cross-section of Figure 5, similar to the outer circumferential surface of the outer ring 11, the flat surface portion 6a1 on the outer diameter side of the joint and the flat surface portion 6a2 on the inner diameter side of the joint are symmetrical with respect to the center PP in the roller width direction.

[0030] A protrusion 17 is provided between the flat surfaces 6a1 and 6a2, projecting from the end faces of the flat surfaces 6a1 and 6a2. In this embodiment, as shown in Figure 6, the side surface 17a of the protrusion 17 is a tapered surface that narrows in width towards the tip of the protrusion 17, and its cross-section is trapezoidal. The protrusion 17 is symmetrical with respect to the center PP in the roller width direction.

[0031] In this embodiment, in the cross-section shown in Figure 5, the contours of the flat surfaces 6a1 and 6a2 of the roller guide surface 6 coincide with the contours of the cylindrical portions 11a1 and 11a2 of the outer ring 11, and the outer circumferential surface of the roller guide surface 6 is shaped to match the shape of the outer circumferential surface of the outer ring 11. Furthermore, the protrusions 17 provided on the roller guide surface 6 engage with the recesses 16 provided on the outer ring 11.

[0032] As described above, a surface hardened layer is formed on both the outer circumferential surface of the outer ring 11 and the roller guide surface 6 by high-frequency induction hardening or the like.

[0033] During rotation of the tripod-type constant velocity universal joint 1 having the above configuration, on the load side, the cylindrical portion 11a1 on the outer diameter side of the outer ring 11 makes line contact with the flat surface portion 6a1 on the outer diameter side of the roller guide surface 6, and the cylindrical portion 11a2 on the inner diameter side of the outer ring 11 makes line contact with the flat surface portion 6a2 on the inner diameter side of the roller guide surface 6. As a result, torque is transmitted at each contact point.

[0034] Even when an operating angle is applied, the cylindrical portions 11a1 and 11a2 of the outer ring 11 make line contact with the flat surfaces 6a1 and 6a2 of the roller guide surface 6, thus suppressing the lateral tilt of the outer ring 11. Furthermore, as the outer ring 11 rolls along the track of the outer joint member, the recess 16 and the protrusion 17 come into contact, suppressing the forward and backward tilt of the outer ring 11. In this case, when the outer ring 11 rolls toward the outer diameter side of the joint, as shown in Figure 6, the inner diameter side of the protrusion 17 comes into contact with the recess 16, and the frictional force acts as a brake, changing the orientation of the outer ring 11, thus avoiding further contact and preventing an increase in rolling resistance. When the outer ring 11 rolls in the opposite direction (i.e., toward the inner diameter side of the joint), the outer diameter side of the protrusion 16 comes into contact with the recess 17, changing the orientation of the outer ring 11. This makes it possible to keep the roller unit 4 horizontal to the track groove 5, preventing unnecessary contact between the outer ring 11 and the outer joint member 2 outside of the torque transmission points, thus avoiding a further increase in rolling resistance and resulting in low vibration.

[0035] If the contact angle θ between the side surface 17a of the convex portion 17 and the recess 16 is less than 20°, when the outer ring 11 moves towards the outer diameter side of the joint due to centrifugal force under no load, contact will also occur on the non-load side, raising concerns about an increase in the rolling resistance of the outer ring 11 due to the wedge effect. If it exceeds 60°, the wedge effect is reduced, but the forging formability of the outer joint member deteriorates, raising concerns about shape defects and a decrease in mold life. Here, the contact angle θ refers to the angle that the tangent P2 of the contact point C between the side surface 17a of the convex portion 17 and the recess 16 makes with respect to the axis P1 of the outer circumferential surface of the cylindrical portions 11a1 and 11a2, as shown in Figure 6. Therefore, it is preferable to set the contact angle θ between the side surface 17a of the convex portion 17 and the recess 16 in the range of 20° to 60°, and more preferably to 35° to 45°.

[0036] Next, a second embodiment of the tripod-type constant velocity universal joint according to the present invention will be described with reference to Figure 7. As shown in Figure 7, in the tripod-type constant velocity universal joint of the second embodiment, similar to the first embodiment, cylindrical portions 11a1 and 11a2 are formed on both sides of the outer circumferential surface of the outer ring 11, flanking the center PP in the width direction of the outer ring 11. In addition, flat portions 6a1 and 6a2 are formed on both sides of the roller guide surface 6, flanking the center PP in the width direction of the outer ring 11.

[0037] On the other hand, in the second embodiment, as shown in Figure 7, a protrusion 18 is provided on the outer circumferential surface of the outer ring 11, between the cylindrical portions 11a1 and 11a2, protruding from the outer circumferential surfaces of the cylindrical portions 11a1 and 11a2. In the second embodiment as well, the protrusion 18 has a trapezoidal cross-section and protrudes continuously in the circumferential direction. Also, on the roller guide surface 6, a recess 19 is provided between the flat surface portions 6a1 and 6a2, recessed from the end faces of the flat surface portions 6a1 and 6a2. In the second embodiment as well, the recess 19 has a trapezoidal cross-section. In the second embodiment as well, the protrusion 18 and the recess 19 are symmetrical with respect to the center PP in the roller width direction.

[0038] In the second embodiment as well, when the operating angle is set, the cylindrical portions 11a1 and 11a2 of the outer ring 11 make line contact with the flat surfaces 6a1 and 6a2 of the roller guide surface 6, thereby suppressing the left-right tilt of the outer ring 11. Furthermore, when the outer ring 11 rolls on the track of the outer joint member, the convex portion 18 and the concave portion 19 come into contact, suppressing the front-back tilt of the outer ring 11, avoiding further contact and preventing an increase in rolling resistance. When the outer ring 11 rolls in the opposite direction (i.e., towards the inner diameter side of the joint), the inner diameter side of the convex portion 18 comes into contact with the concave portion 19, changing the orientation of the outer ring 11.

[0039] Except for the matters described above, the configuration and functions of each part of the second embodiment are the same as those of the first embodiment, so the explanation of the overlapping parts will be omitted.

[0040] Figure 8 shows that, in the first embodiment shown in Figure 5, a guide surface 20 is provided within the track groove of the outer joint member 2 to guide the axial outer end surface 11b of the outer ring 11. That is, the surface of the track groove 5 of the outer joint member 2 that the axial outer end surface 11b of the outer ring 11 contacts is straight.

[0041] By providing the guide surface 20, the axial outer end surface 11b of the outer ring 11 comes into contact with the guide surface 20, increasing the restraining force against changes in the posture of the outer ring 11. For example, even when the gap between the convex portion 17 and the concave portion 16 is large, the forward and backward tilt of the outer ring 11 can be suppressed. In other words, the deterioration of the rolling resistance and NVH of the outer ring 11 can be suppressed more stably. Furthermore, by reducing the volume inside the outer joint member, the amount of lubricating grease contained can be reduced, thereby reducing the overall mass and cost.

[0042] Other forms of the guide surface include the guide surface 20a shown in Figure 9(a), which may be provided at a position spaced apart from the roller guide surface 6, or the guide surface 20b shown in Figure 9(b), which may be provided only on the roller guide surface 6 side. Furthermore, in the second embodiment shown in Figure 7, guide surfaces as shown in Figures 8, 9(a), and 9(b) may be provided.

[0043] The recesses and protrusions are not limited to trapezoidal shapes as in the first and second embodiments, but may have other shapes. For example, as shown in Figure 10, the protrusions 21 and recesses 22 may have an R shape. However, the contact angle θ between the recesses and protrusions is preferably in the range of 20° to 60°, and more preferably 35° to 45°. Although Figure 10 shows an outer joint member 2 with a guide surface 20 in the track groove, as shown in Figures 5 and 7, the shapes of the recesses and protrusions can be various even without a guide surface 20.

[0044] Furthermore, the present invention is not limited to the embodiments described above, and can be widely applied to tripod-type constant velocity universal joints having other configurations, as long as they are of the double-roller type.

[0045] For example, as shown in the embodiment in Figure 11, the outer circumferential surface 7a of the leg shaft 7 can be formed as a convex curved surface (for example, a convex arc in cross-section), and the inner circumferential surface 12a of the inner ring 12 can be formed as a cylindrical surface. Furthermore, as shown in the embodiment in Figure 12, the outer circumferential surface 7a of the leg shaft 7 can be formed as a convex curved surface (for example, a convex arc in cross-section), and the inner circumferential surface 12a of the inner ring 12 can be formed as a concave spherical surface that fits with the outer circumferential surface 7a of the leg shaft (washers 14 and 15 can also be made unnecessary by providing flanges at both ends of the inner diameter of the outer ring). In any embodiment, except for the differences described above, the same reference numerals are used for members and elements common to the first and second embodiments described in Figures 1 to 10, and redundant explanations are omitted.

[0046] The tripod-type constant velocity universal joint 1 described above is not limited to automobile drive shafts, but can be widely used in power transmission paths for automobiles, industrial equipment, and the like. [Explanation of symbols]

[0047] 1. Tripod type constant velocity universal joint 2. Outer joint member 3. Tripod Member 4 Roller Units 5 Track grooves 6. Roller guide surface 6a1 Cylindrical section 6a2 Cylindrical section 7 Leg axis 7a Outer surface of the leg shaft 8 center hole 11. Laura (Outering) 11a1 Flat surface part 11a2 Flat surface part 12 Inner Ring 16, 19, 22 recesses 17, 18, 21 Convex parts 20, 20a, 20b Guide surfaces O Axis of the leg axis P Roller width direction center θ contact angle

Claims

1. In a tripod-type constant velocity universal joint comprising an outer joint member having track grooves extending axially at three locations in the circumferential direction, each track groove having a pair of roller guide surfaces arranged opposite each other in the circumferential direction, a tripod member having three radially protruding leg shafts, rollers inserted into the track grooves, and an inner ring fitted onto the leg shafts and supporting the rollers rotatably, wherein the rollers are configured to move axially along the roller guide surfaces of the outer joint member, On the outer circumferential surface of the roller, cylindrical portions are provided on both sides of the center in the width direction of the roller, and recesses are provided between the cylindrical portions that are recessed from the outer circumferential surface of the cylindrical portions. A tripod-type constant velocity universal joint characterized in that the roller guide surface has flat surface portions on both sides of the center in the width direction of the roller, and a convex portion is provided between the flat surface portions that protrudes from the end face of the flat surface portion and engages with the concave portion.

2. In a tripod-type constant velocity universal joint comprising an outer joint member having track grooves extending axially at three locations in the circumferential direction, each track groove having a pair of roller guide surfaces arranged opposite each other in the circumferential direction, a tripod member having three radially protruding leg shafts, rollers inserted into the track grooves, and an inner ring fitted onto the leg shafts and supporting the rollers rotatably, wherein the rollers are configured to move axially along the roller guide surfaces of the outer joint member, On the outer circumferential surface of the roller, cylindrical portions are provided on both sides of the center in the width direction of the roller, and protrusions are provided between the cylindrical portions, extending from the outer circumferential surface of the cylindrical portions. A tripod-type constant velocity universal joint characterized in that the roller guide surface has flat surfaces on both sides of the center in the width direction of the roller, and recesses are provided between the flat surfaces, recessed from the end faces of the flat surfaces, into which the protrusions engage.

3. The tripod-type constant velocity universal joint according to claim 1 or 2, characterized in that the contact angle between the side surface of the convex portion and the concave portion is 20° or more and 60° or less.

4. The tripod-type constant velocity universal joint according to claim 3, characterized in that the contact angle is 35° or more and 45° or less.

5. The tripod-type constant velocity universal joint according to claim 1 or 2, characterized in that the outer circumferential surface of the leg shaft is formed as a convex curved surface and the inner circumferential surface of the inner ring is formed as a cylindrical surface.

6. The tripod-type constant velocity universal joint according to claim 1 or 2, characterized in that the outer circumferential surface of the leg shaft is formed as a convex curved surface and the inner circumferential surface of the inner ring is formed as a concave spherical surface.

7. A tripod-type constant velocity universal joint according to claim 1 or 2, characterized in that a guide surface is provided in the track groove of the outer joint member for guiding the axial outer end surface of the roller.

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