Tripod type constant velocity universal joint

Abstract

To provide a tripod type constant velocity universal joint of a double roller type which can ease concentration of stress exerted on a needle-like roller end surface.SOLUTION: A tripod type constant velocity universal joint includes: an outer joint member having a roller guide surface which is disposed facing track grooves arranged at trisected positions in a circumferential direction of an inner periphery in the circumferential direction; a tripod member having three leg shafts protruding from the trisected positions in the circumferential direction to the radial outer side; and roller assemblies 4 respectively fitted on the leg shafts. The roller assembly includes: an inner ring 12 fitted on the leg shaft; a roller 11 inserted and fitted on the roller guide surface; multiple needle-like rollers 13 disposed between a cylindrical outer peripheral surface 12b of the inner ring and a cylindrical inner peripheral surface of the roller; and a pair of washers 14, 15 which are disposed at both axial sides of the needle-like rollers and the inner ring and are attached at their outer peripheral edges to an inner periphery of the roller. Drop shape parts D are formed at both axial ends of the cylindrical outer peripheral surface 12b of the inner ring.SELECTED DRAWING: Figure 12

Description

Technical Field

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

Background Art

[0002] A constant velocity joint that constitutes a power transmission system of an automobile or various industrial machines can connect two shafts on the driving side and the driven side so as to transmit torque, and can transmit a rotational torque at a constant speed even when the two shafts take an operating angle. Constant velocity joints are roughly classified into fixed constant velocity joints that allow only angular displacement and sliding constant velocity joints that allow both angular displacement and axial displacement. For example, in a drive shaft that transmits power from an engine of an automobile to a drive wheel, a sliding constant velocity joint is used on the differential side (inboard side), and a fixed constant velocity joint is used on the drive wheel side (outboard side).

[0003] One type of sliding constant velocity joint is a tripod constant velocity joint. This tripod constant velocity joint is known to have a single roller type and a double roller type for the roller, which is a torque transmission member. The double roller type tripod constant velocity joint (hereinafter, also simply referred to as a tripod constant velocity joint) mainly consists of an outer joint member, a tripod member as an inner joint member, and a roller assembly as a torque transmission member.

[0004] The outer joint member has three linear track grooves extending axially at three equal circumferential divisions on its inner circumference. On both sides of each track groove, roller guide surfaces are formed, facing each other circumferentially and extending axially. The outer joint member houses a tripod member and a roller assembly. The tripod member has three radially protruding leg shafts. The roller assembly mainly consists of a roller, an inner ring positioned inside the roller and fitted onto the leg shafts, and a plurality of needle-shaped rollers interposed between the roller and the inner ring, and is housed in the track grooves of the outer joint member. The roller assembly, consisting of the inner ring, needle-shaped rollers, and roller, is not separated by a pair of washers. The washers are divided at one point in the circumferential direction and are designed to be fitted into the annular groove on the cylindrical inner surface of the roller in an elastically reduced diameter state. The inner surface of the inner ring forms an arc-shaped convex surface in a longitudinal cross-section including the axis of the inner ring.

[0005] The outer circumferential surface of each leg shaft of the tripod member has a straight shape in a longitudinal cross-section including the axis of the leg shaft, and a substantially elliptical shape in a cross-section perpendicular to the axis of the leg shaft. It contacts the inner circumferential surface of the inner ring in a direction perpendicular to the axis of the joint, and a gap is formed between it and the inner circumferential surface of the inner ring in the direction of the axial direction of the joint. In this tripod-type constant velocity universal joint, the rollers of the roller assembly mounted on the leg shaft of the tripod member roll on the roller guide surface of the track groove of the outer joint member. Because the cross-section of the leg shaft is substantially elliptical, when the tripod-type constant velocity universal joint takes an operating angle, the axis of the tripod member is inclined with respect to the axis of the outer joint member, but the roller assembly can be inclined with respect to the axis of the leg shaft of the tripod member. Therefore, since the rollers roll correctly on the roller guide surface, induced thrust and sliding resistance can be reduced, and vibration of the joint can be reduced (Patent Document 1). The shape of the three track grooves, which have roller guide surfaces formed on the outer joint member, is mainly applied to angular contact or circular contact.

[0006] In a tripod-type constant velocity universal joint, when the operating angle is taken, the center of the joint, the center of the tripod member, and the center of the shaft do not geometrically coincide. Therefore, the axis of the leg axis of the tripod member rotates while being slightly tilted with respect to the center line of the track groove, which is formed in the circumferential direction in three equal parts at 120° intervals. Due to this tilt, the inner ring of the roller assembly moves relative to the leg axis of the tripod member in the vertical direction. In the tripod-type constant velocity universal joint proposed in Patent Document 2, even when the needle roller and inner ring are pressed against the washer by a vertical load, the distance between the pair of washers is gradually reduced from the outer diameter side to the inner diameter side of the roller assembly, and the end faces of the needle rollers and the washers come into contact in a substantially planar manner, thereby allowing the roller assembly to rotate smoothly. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2001-132766 [Patent Document 2] Japanese Patent Publication No. 2008-267404 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] The aforementioned vertical load was investigated by focusing on the fact that in a double-roller tripod-type constant velocity universal joint, it occurs when the roller assembly is tilted in the rotational direction (also called lateral tilting) with respect to the center of the roller guide surface of the outer joint member. In this state, the contact between the cylindrical outer surface of the inner ring, the needle rollers, and the cylindrical inner surface of the outer rollers occurs repeatedly in an unbalanced direction. When an excessive load is applied in this state, edge stress occurs at the point of contact with the end face of the needle rollers, which can lead to a reduced lifespan in some cases, and it was found that avoiding edge stress is an important technical issue. This problem differs in its focus from the method described in Patent Document 2 mentioned above, and it is an issue that cannot be solved.

[0009] In view of the above-mentioned problems, the present invention aims to provide a double-roller type tripod-type constant velocity universal joint that improves durability by mitigating the concentration of edge stress acting on the end faces of needle rollers in a roller assembly, and enables smooth rotational operation. [Means for solving the problem]

[0010] To achieve the above objective, the inventors investigated the behavior of the components of a roller assembly in a double-roller tripod-type constant velocity universal joint while it was operating at an angle. As a result, they concluded that although the rolling amount of the components of the roller assembly of the tripod-type constant velocity universal joint is small compared to a typical rolling bearing, the relative movement of the components of the roller assembly is extremely severe compared to a typical rolling bearing. Based on this result, they arrived at a new idea for a unique internal specification that takes into account the relative movement of the components of the roller assembly, leading to the present invention. Detailed information on operation and behavior, as well as insights into the development process leading to the present invention, will be described later.

[0011] As a technical means to achieve the aforementioned objective, the present invention provides a tripod-type constant velocity universal joint comprising: an outer joint member having three track grooves extending axially at three equally spaced positions in the circumferential direction of its inner circumference, and a roller guide surface arranged circumferentially opposite to the track grooves; a tripod member having three leg shafts projecting radially outward from the three equally spaced positions in the circumferential direction; and a roller assembly enclosed on the leg shafts, wherein the roller assembly comprises an inner ring enclosed on the leg shafts, a roller inserted into the roller guide surface, a plurality of needle-shaped rollers arranged between the cylindrical outer surface of the inner ring and the cylindrical inner surface of the roller, and a pair of washers arranged on both axial sides of the needle-shaped rollers and the inner ring, with their outer edges attached to the inner circumference of the roller, characterized in that drop-shaped portions are formed at both axial ends of the cylindrical outer surface of the inner ring. The above configuration makes it possible to realize a double-roller type tripod-type constant velocity universal joint that reduces the concentration of edge stress acting on the end faces of the needle rollers in the roller assembly, thereby improving durability and enabling smooth rotational operation.

[0012] Specifically, when Li is the length of the drop-shaped portion of the inner ring in the axial direction, r is the axial dimension of the end face radius of the needle roller, and Ia is the amount of axial movement of the inner ring within the roller assembly, it is preferable that the relationship Li > (Ia + r) is satisfied. This allows the inner ring and needle roller to be biased to an unavoidable limit on either the upper or lower side due to cumulative machining accuracy and other factors, while still maintaining the effect of mitigating the concentration of edge stress acting on the end face of the needle roller in the roller assembly, thereby improving durability and enabling smooth rotational operation.

[0014] By connecting the straight portion and the drop-shaped portion of the cylindrical outer surface of the inner ring tangentially, the increase in surface pressure can be suppressed.

[0015] Preferably, the inner surface of the inner ring is formed as an arc-shaped convex surface in the longitudinal cross-section of the inner ring, the outer surface of the leg shaft is straight in the longitudinal cross-section including the axis of the leg shaft, and is substantially elliptical in the cross-section perpendicular to the axis of the leg shaft, the outer surface of the leg shaft abuts 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 leg shaft and the inner surface of the inner ring in the axial direction of the joint, and the roller is able to tilt within the track groove. This makes the tilting motion of the roller within the track groove smoother, which reduces induced thrust and sliding resistance and reduces vibration of the joint.

[0016] Either angular contact or circular contact can be applied as the contact configuration between the roller and the roller guide surface. [Effects of the Invention]

[0017] According to the present invention, it is possible to realize a double-roller type tripod-type constant velocity universal joint that reduces the concentration of edge stress acting on the end faces of the needle rollers in the roller assembly, thereby improving durability and enabling smooth rotational operation. [Brief explanation of the drawing]

[0018] [Figure 1] It is a longitudinal sectional view of a tripod constant velocity joint according to a first embodiment of the present invention. [Figure 2] It is a cross-sectional view taken along line A-A of FIG. 1 and viewed in the arrow direction. [Figure 3] It is a plan view of the roller assembly and the leg shaft taken along line B-B of FIG. 1 and viewed in the arrow direction. [Figure 4] It is a longitudinal sectional view of the roller assembly at line E-E of FIG. 3. [Figure 5] It is a view for explaining the contact state between the roller and the roller guide surface in a cross section of approximately one-third of the circumferential direction of the outer joint member and one roller assembly on the upper side of FIG. 2. [Figure 6] It is a longitudinal sectional view showing the state in which the tripod constant velocity joint of FIG. 1 has taken an operating angle. [Figure 7] [[ID=二十三]]It is a longitudinal sectional view with plane E including the axis of the leg shaft of the tripod member added to FIG. 6, in which the leg shaft and the roller assembly are located in the track groove at the top dead center (0° phase) of the outer joint member in the state of taking an operating angle. [Figure 8] It is a view for explaining the state, operation, and behavior in which the leg shaft and the roller assembly are located in the track groove at the top dead center (0° phase) of the outer joint member in the state of taking an operating angle. FIG. (a) is a longitudinal sectional view, and FIG. (b) is a cross-sectional view. [Figure 9] It is a view for explaining the state, operation, and behavior in which the roller assembly 4(1) of FIG. 8(b) has rotated clockwise up to 90° phase. FIG. (a) is a longitudinal sectional view, and FIG. (b) is a cross-sectional view. [Figure 10] It is a view for explaining the state, operation, and behavior in which the roller assembly 4(1) of FIG. 8(b) has further rotated clockwise up to 180° phase. FIG. (a) is a longitudinal sectional view, and FIG. (b) is a cross-sectional view. [Figure 11] FIG. (a) is a view showing the combined operation and behavior of the left and right tilting of the roller assembly in the track groove. FIG. (b) is a cross-sectional view showing the left and right tilting of right rotation. FIG. (c) is a cross-sectional view showing the horizontal state. FIG. (d) is a cross-sectional view showing the left and right tilting of left rotation. [Figure 12] It is an enlarged longitudinal sectional view of the roller assembly of the present embodiment. [Figure 13] (a) The figure is a partial longitudinal sectional view showing the axial movement amount of the inner lining within the roller assembly of the present embodiment, and (b) the figure is an enlarged longitudinal sectional view of part K in (a) figure. [Figure 14] It is an enlarged longitudinal sectional view of the roller assembly under consideration. [Figure 15] It is a partial cross-sectional view showing a modified example in which the contact state between the roller and the roller guide surface in the roller assembly of the first embodiment is circular contact. [Figure 16] It is a cross-sectional view of a tripod constant velocity joint according to the second embodiment of the present invention. [Figure 17] It is a cross-sectional view of a modified example of a tripod constant velocity joint according to the second embodiment of the present invention.

Mode for Carrying Out the Invention

[0019] The tripod constant velocity joint according to the first embodiment of the present invention is shown in FIGS. 1 to 13. First, the overall configuration of the tripod constant velocity joint of the present embodiment will be described based on FIGS. 1 to 6. FIG. 1 is a longitudinal sectional view of the tripod constant velocity joint according to the present embodiment, and FIG. 2 is a cross-sectional view taken along line A-A of FIG. 1. However, in FIG. 2, the tripod member and the two lower roller assemblies are not shown in cross-section, and the shaft is not shown. The two lower roller assemblies in FIG. = 2 do not appear in FIG. 1 which is a longitudinal sectional view. FIG. 3 is a plan view of the roller assembly and the leg shaft taken along line B-B of FIG. 1, and FIG. 4 is a longitudinal sectional view of the roller assembly at line E-E of FIG. 3. FIG. 5 is a cross-sectional view of approximately one-third of the circumferential direction of the outer joint member and the upper roller assembly in FIG. 2, and is a view for explaining the contact state between the roller and the roller guide surface. Cross-sectional hatching is omitted. FIG. 6 is a longitudinal sectional view showing the state in which the tripod constant velocity joint of FIG. 1 has taken an operating angle.

[0020] 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 assembly 4 as a torque transmission member. The outer joint member 2 has a cup portion 2a with one end open, and three linear track grooves 5 extending axially are formed at three equally spaced positions in the circumferential direction of the inner circumference. On both sides of each track groove 5, roller guide surfaces 6 are formed, which are arranged opposite each other in the circumferential direction and each extends axially. The roller guide surfaces 6 have a substantially partially cylindrical cross-section. The tripod member 3 and the roller assembly 4 are housed inside the outer joint member 2.

[0021] The tripod member 3 has three leg shafts 7 that protrude radially outward from three equally spaced positions in the circumferential direction. A shaft 9 is spline-fitted into the central hole 8 of the tripod member 3 and fixed axially by a retaining ring 10. The roller assembly 4 mainly consists of a roller 11, an inner ring 12 positioned inside the roller 11 and fitted onto the leg shafts 7, and a plurality of needle-shaped rollers 13 interposed between the roller 11 and the inner ring 12. The roller assembly 4 is housed in the track groove 5 of the outer joint member 2, and the center Cr (see Figure 4) of the roller assembly 4 (roller 11) is located on the pitch circle PC of the track groove 5.

[0022] As shown in Figure 4, the needle-shaped rollers 13 are arranged in a so-called full-roller configuration without a retainer between the cylindrical inner surface 11b of the roller 11 and the cylindrical outer surface 12b of the inner ring 12, with the cylindrical inner surface 11b of the roller 11 serving as the outer raceway surface and the cylindrical outer surface 12b of the inner ring 12 serving as the inner raceway surface. The inner surface 12a of the inner ring 12 forms an arc-shaped convex surface in a longitudinal cross-section containing the axis of the inner ring 12. This arc-shaped convex surface has a radius of curvature ri of approximately 30 mm, for example, in order to allow for the left-right tilt of the leg shaft 7 relative to the inner ring 12 caused by the runout characteristic of tripod-type constant velocity universal joints. Furthermore, as shown in Figure 3, torque is transmitted when the leg shaft 7, which has a substantially elliptical cross-section, comes into contact with the inner ring 12, which has a circular inner surface 12a. Therefore, in order to alleviate the surface pressure at the contact point between the leg shaft 7 and the inner ring 12 and to ensure the strength of the leg shaft 7, the ellipticity b / a of the major axis a and minor axis b of the substantially elliptical leg shaft 7 and the radius of curvature ri of the inner surface 12a of the inner ring 12 (see Figure 4) are set.

[0023] As shown in Figure 4, the outer circumferential surface 11a of the roller 11 is formed as a partial spherical surface with a radius of curvature ro, with its center of curvature on the axis 4x of the roller assembly 4, or in other words, on the axis 7x of the leg shaft 7 shown in Figure 3. The roller assembly 4, consisting of the inner ring 12, needle rollers 13, and roller 11, is not separated by washers 14 and 15. The washers 14 and 15 are divided at one point in the circumferential direction (see Figure 3) and are designed to be fitted into the annular groove of the cylindrical inner circumferential surface 11b of the roller 11 in an elastically reduced diameter state.

[0024] As shown in Figures 1 and 2, the outer circumferential surface 7a of each leg shaft 7 of the tripod member 3 has a straight shape in a longitudinal cross-section that includes the axis 7x of the leg shaft 7 (see Figure 3). Also, as shown in Figure 3, the outer circumferential surface 7a of the leg shaft 7 has a substantially elliptical shape in a cross-section perpendicular to the axis 7x of the leg shaft 7, and contacts the inner circumferential surface 12a of the inner ring 12 in the direction perpendicular to the axis of the joint, i.e., in the direction of the major axis a, and a gap m is formed between the inner circumferential surface 12a of the inner ring 12 in the direction of the axial direction of the joint, i.e., in the direction of the minor axis b. In the tripod-type constant velocity universal joint 1, the rollers 11 of the roller assembly 4 mounted on the leg shaft 7 of the tripod member 3 roll on the roller guide surface 6 of the track groove 5 of the outer joint member 2.

[0025] As shown in Figure 5, the outer circumferential surface 11a of the roller 11 is formed as a partial spherical surface with a radius of curvature ro, where the center of curvature Or lies on the axis 7x of the leg shaft 7. The center of curvature Or is also the center Cr of the roller assembly. The roller guide surface 6 is formed as a Gothic arch-shaped cross-section with a radius of curvature Rt, where the center of curvature ORt lies beyond the center line 5x of the track groove 5 on a line passing through the intersection T of the pitch circle PC of the track groove 5 and the center line 5x of the track groove 5, and extends parallel to the axis of the joint. The radius of curvature Rt is set to be appropriately larger than the radius of curvature ro. Therefore, the outer circumferential surface 11a of the roller 11 and the roller guide surface 6 make angular contact at two points with a contact angle α with respect to the horizontal line XX passing through the intersection T. A small track gap δ is provided between the roller guide surface 6 and the outer circumferential surface 11a of the roller 11. In Figure 5, the center line 5x of the track groove and the axis 7x of the leg shaft 7 are shown to coincide. Therefore, the track clearance on one side is δ / 2.

[0026] Since the cross-section of the leg shaft 7 is substantially elliptical, at the relatively small operating angles commonly used, the axis of the tripod member 3 is inclined with respect to the axis of the outer joint member 2, as shown in Figure 6. However, the roller assembly 4 can be inclined with respect to the axis of the leg shaft 7 of the tripod member 3. Therefore, the roller 11 of the roller assembly 4 and the roller guide surface 6 are prevented from being obliquely aligned and roll correctly, thereby reducing induced thrust and sliding resistance, and achieving low vibration of the joint. In this specification and in the claims, substantially elliptical shape is not limited to a literally elliptical shape, but includes shapes generally referred to as egg-shaped, oval-shaped, etc.

[0027] On the other hand, if the angle exceeds a predetermined angle beyond the normal operating angle (for example, about 15°), the outer circumferential surface 7a of the leg shaft 7 and the inner circumferential surface 12a of the inner ring 12 interfere with each other, as shown in Figure 3, and the roller assembly 4 (roller 11) can no longer tilt relative to the leg shaft 7. Since the angle to which the roller assembly 4 can tilt relative to the leg shaft 7 is limited, if the angle exceeds the predetermined angle beyond the normal operating angle, the roller assembly 4 needs to tilt by the amount of the insufficient angle relative to the track groove 5. However, as shown in Figure 4, since the outer circumferential surface 11a of the roller 11 is formed as a partial spherical surface with a radius of curvature ro and its center of curvature on the axis 7x of the leg shaft 7, the roller assembly 4 can tilt within the track groove 5 and can accommodate large operating angles.

[0028] The overall configuration of the tripod-type constant velocity universal joint 1 of this embodiment is as described above. Next, the characteristic configuration will be described. The characteristic configuration is as follows. (1) In a double-roller type tripod-type constant velocity universal joint, drop-shaped portions are formed at both axial ends of the cylindrical outer surface of the inner ring. (2) As an advantageous configuration, in a double-roller tripod type constant velocity universal joint, if the length of the drop-shaped portion of the inner ring in the axial direction is Li, the axial dimension of the end face radius of the needle roller is r, and the amount of axial movement of the inner ring within the roller assembly is Ia, then the relationship Li > (Ia + r) To satisfy.

[0029] To facilitate understanding of the characteristic configuration described above, the results and findings of studies on the operation and behavior of the roller assembly of the tripod-type constant velocity universal joint during the development process will be explained based on Figures 7 to 11. First, the axial relative movement and lateral tilt of the roller assembly and leg axis corresponding to specific phases will be explained in detail based on Figures 7 to 10, and the behavior of the lateral tilt of the roller assembly within the track groove will be summarized and explained based on Figure 11.

[0030] Figure 7 is a longitudinal cross-sectional view of Figure 6, in which the leg shaft and roller assembly are positioned in the track groove at the top dead center (0° phase) of the outer joint member with the operating angle taken, with a plane E including the axis 7x of the leg shaft 7 of the tripod member 3 added. This figure will be used as the basis for the following explanation. Figure 8 is a diagram illustrating the state, operation, and behavior of the leg shaft and roller assembly positioned in the track groove at the top dead center (0° phase) of the outer joint member with the operating angle taken. Figure 8(a) is a longitudinal cross-sectional view, and Figure 8(b) is a transverse cross-sectional view. In Figure 8(b), the axis 7x of the leg shaft of the tripod member is shown as a thick dashed line, and the outline of the tripod member is omitted from the illustration. The two lower roller assemblies 4 of Figure 2 mentioned above are not shown in the longitudinal cross-sectional views of Figure 8(a) and Figure 7.

[0031] As shown in Figure 7, when the joint takes an operating angle θ, the plane E containing the axis 7x of the leg shaft 7 of the tripod member 3 is tilted by the operating angle θ. The tripod member 3 rotates on this plane E. Even when the operating angle θ is taken, the center Cr of the roller assembly 4 (see Figure 4) is located on the axis 7x of the leg shaft 7 of the tripod member 3 and is constrained to the pitch circle PC of the track groove 5. As shown in Figures 8(a) and 8(b), the upper roller assembly 4(1) is located at a 0° phase (ψ=0°) of the opening side I of the cup portion 2a of the outer joint member 2. This state is called the 0° phase state. In this state, the upper roller assembly 4(1) is in a horizontal position, and the axis 4x of the roller assembly 4(1) is not tilted left or right with respect to the vertical plane containing the center line 5x of the track groove 5. Also, the axis 7x of the upper leg shaft 7 of the tripod member 3 is not tilted left or right with respect to the vertical plane containing the center line 5x of the track groove 5. The arrows displayed on the radially outward side of the outer joint member 2 indicate that a rotational torque is applied to the outer joint member 2 in the direction of the arrow. In other words, the left side of the roller assembly 4 is the load side. The same applies to Figures 9(b) and 10(b), which will be described later.

[0032] The three leg shafts 7 of the tripod member 3 are formed to protrude radially outward from three equally spaced positions in the circumferential direction, and the positional relationship of the three leg shafts is fixed. The center Cr of each roller assembly 4 (see Figure 4) is located on the axis 7x of the leg shaft 7 of the tripod member 3 and is constrained to the pitch circle PC of the track groove 5. As shown in Figure 8(b), when an operating angle θ is taken, with the axes 7x of the three leg shafts 7 located on the inclined plane E, the center Ct of the tripod member 3 shifts downward relative to the joint center Cj, causing the tripod member 3 to tilt by the operating angle θ. As a result, the axis 7x of the roller assembly 4(1) and the leg shaft 7 into which this roller assembly 4(1) is enclosed does not tilt laterally with respect to the vertical plane containing the center line 5x of the track groove 5, but there is a relative axial movement between the inner ring 12 of the roller assembly 4(1) and the leg shaft 7.

[0033] On the other hand, the axes 4x of the two lower roller assemblies 4(2) and 4(3), and the axis 7x of the leg shaft 7 into which these roller assemblies 4(2) and 4(3) are enclosed, undergo a left-right tilt along with the axial relative movement of the leg shaft 7 with respect to the inner ring 12. Depending on the direction of the left-right tilt of the axis 7x of the leg shaft 7 and the direction of the axial relative movement of the leg shaft 7 with respect to the inner ring 12, as shown in Figure 8(b), the lower right roller assembly 4(2) undergoes a left-right tilt β0 with a counter-clockwise rotation as indicated by the arrow, and the lower left roller assembly 4(3) undergoes a right-clockwise tilt β0 as indicated by the arrow.

[0034] The joint center Cj is the curvature center of the pitch circle radius PCR of the track groove 5 of the outer joint member 2. The center Ct of the tripod member 3 and the center Cs of the shaft coincide. This condition is also the case in Figures 9(b) and 10(b), which will be described later. In Figure 8(b), for ease of understanding, a schematic diagram with an operating angle θ of approximately 30° is used, and the amount of displacement of the center Ct of the tripod member 3 relative to the joint center Cj and the left-right tilt β are exaggerated in the illustration. A similar illustration is shown in Figures 9(b) and 10(b), which will be described later.

[0035] The state in which the roller assembly 4(1) is positioned at a 90° phase after rotating the joint clockwise will be explained with reference to Figure 9. Figure 9 is a diagram illustrating the state, operation, and behavior of the roller assembly 4(1) in Figure 8(b) after rotating clockwise to a 90° phase, with Figure 9(a) being a longitudinal section view and Figure 9(b) being a transverse section view. As shown in Figure 9(b), when the roller assembly 4(1) is positioned at a 90° phase (ψ=90°), the axis 4x of the roller assembly 4(1) is not tilted to the left or right with respect to the horizontal plane containing the center line 5x of the track groove 5. Similarly, the axis 7x of the leg shaft 7 is also not tilted to the left or right with respect to the horizontal plane containing the center line 5x of the track groove 5.

[0036] The center Cr of each roller assembly 4 (see Figure 4) is located on the axis 7x of the leg shaft 7 of the tripod member 3 and is constrained to the pitch circle PC of the track groove 5. Therefore, as shown in Figure 9(b), when the roller assembly 4(1) is in a 90° phase, the center Ct of the tripod member 3 is relative to the joint center Cj. rightIt shifts to the side. As a result, the axis 4x of the roller assembly 4(1) and the axis 7x of the leg shaft 7 into which this roller assembly 4(1) is enclosed do not tilt to the left or right with respect to the horizontal plane containing the center line 5x of the track groove 5, but there is a relative axial movement between the inner ring 12 of the roller assembly 4(1) and the leg shaft 7. The axis 4x of the diagonally lower roller assembly 4(2) and the axis 7x of the leg shaft 7 are shown as arrows, along with the axial relative movement of the leg shaft 7 with respect to the inner ring 12. right A rotational tilt β90 occurs. Along with the axial relative movement of the leg shaft 7 with respect to the inner ring 12, the axis 4x of the diagonally upper roller assembly 4(3) and the axis 7x of the leg shaft 7 are as shown by the arrows. left A rotational tilt of β90 occurs.

[0037] The state in which the roller assembly 4(1) is positioned at a 180° phase by further rotating the joint clockwise will be explained with reference to Figure 10. Figure 10 is a diagram illustrating the state, operation, and behavior of the roller assembly 4(1) in Figure 8(b) when it has been rotated clockwise to a 180° phase with respect to the inner side II of the cup portion 2a of the outer joint member 2. Figure 10(a) is a vertical cross-sectional view, and Figure 10(b) is a horizontal cross-sectional view. The center Cr of each roller assembly 4 (see Figure 4) is located on the axis 7x of the leg axis 7 of the tripod member 3 and is constrained to the pitch circle PC of the track groove 5. Therefore, as shown in Figure 10(b), when the roller assembly 4(1) is positioned at a 180° phase (ψ=180°), the roller assembly 4(1) returns to a horizontal position, and the axis 4x of the roller assembly 4(1) does not tilt left or right with respect to the vertical plane containing the center line 5x of the track groove 5. Furthermore, the axis 7x of the leg shaft 7 into which the roller assembly 4(1) is enclosed is not tilted from side to side with respect to the vertical plane containing the center line 5x of the track groove 5.

[0038] Because the center Ct of the tripod member 3 is shifted upward relative to the joint center Cj, the roller assembly 4(1) and the leg shaft 7 into which this roller assembly 4(1) is enclosed do not tilt laterally with respect to the vertical plane containing the center line 5x of the track groove 5, but relative axial movement occurs between the inner ring 12 of the roller assembly 4(1) and the leg shaft 7. The axis 4x of the upper left roller assembly 4(2) and the axis 7x of the leg shaft 7 into which this roller assembly 4(2) is enclosed experience a leftward rotational tilt β180 as indicated by the arrow, along with the axial relative movement of the leg shaft 7 with respect to the inner ring 12. Also, the axis 4x of the upper right roller assembly 4(3) and the axis 7x of the leg shaft 7 into which this roller assembly 4(3) is enclosed experience a rightward rotational tilt β180 as indicated by the arrow, along with the axial relative movement of the leg shaft 7 with respect to the inner ring 12.

[0039] In the above explanation, for ease of understanding, we have specifically described how the left-right tilt of the axis 4x of the roller assembly 4 and the axis 7x of the leg shaft 7 into which the roller assembly 4 is housed occur, and how the leg shaft 7 moves axially relative to the inner ring 12, corresponding to the states in which the roller assembly 4(1) is positioned at 0° phase (ψ=0°), 90° phase (ψ=90°), and 180° phase (ψ=180°). In reality, in the double-roller type tripod constant velocity universal joint 1 of this embodiment, while the joint is operating at an angle, the left-right tilt of the axis 4x of the roller assembly 4 and the axis 7x of the leg shaft 7 into which the roller assembly 4 is housed, as well as the axial relative movement of the leg shaft 7 with respect to the inner ring 12, occur repeatedly and continuously while fluctuating.

[0040] The behavior of the roller assembly's lateral tilt within the track groove is summarized and explained based on Figure 11. Figure 11(a) is a composite diagram showing the lateral tilt behavior of the roller assembly within the track groove, Figure 11(b) is a cross-sectional view showing right-rotating lateral tilt, Figure 11(c) is a cross-sectional view showing the horizontal state, and Figure 11(d) is a cross-sectional view showing left-rotating lateral tilt.

[0041] As shown in Figure 11(a), the roller assembly 4 exhibits a horizontal orientation, clockwise rotation, or counterclockwise tilt, corresponding to the aforementioned phases. The horizontal orientation of the roller assembly 4 in Figure 11(c) will be further explained, for example, in the state of phase 0° (ψ=0°) as shown in Figures 8(a) and 8(b). The leg shaft 7 is tilted by the operating angle θ (see Figure 7). When the roller assembly 4(1) rotates and reaches phase 0° (ψ=0°) from a phase just before phase 0° (ψ=0°), the roller assembly 4(1) assumes a horizontal orientation. Although the leg shaft 7 is tilted by the operating angle θ, when viewed in a cross-section perpendicular to the axis of the outer joint member, it assumes a horizontal orientation with respect to the leg shaft 7. This is because, at the moment phase 0° (ψ=0°) is reached, the axial relative movement of the leg shaft 7 with respect to the inner ring 12 of the roller assembly 4(1) instantaneously becomes 0, and the load on the leg shaft 7 to move the inner ring 12 in the vertical direction disappears. Therefore, the roller assembly 4(1) is in a horizontal position as described above, and the inner ring 12 and needle rollers 13 are positioned in the axial center between the washers 14 and 15. Both ends of the inner ring 12 have an axial gap (half of the axial movement amount Ia) that is bisected relative to the washers 14 and 15. In addition, the horizontal position of the roller assembly 4(1) also includes a horizontal position in which the axis 7x of the leg shaft 7 and the axis 4x of the roller assembly 4(1) coincide, as shown in the phase 90° (ψ=90°) state in Figures 9(a) and 9(b).

[0042] To elaborate on the rightward rotation and left-right tilt of the roller assembly 4 in Figure 11(b), for example, the axis 7x of the leg shaft 7 into which the lower left roller assembly 4(3) shown in Figure 8(b) is enclosed is due to the rotation of the outer joint member in the direction of the arrow. When the inner ring 12 of the roller assembly 4 moves relative to the leg axis 7 of the tripod member 3 The leg shaft 7 pulls the inner ring 12 of the roller assembly 4(3) downwards, causing a rightward rotation and tilt. Simultaneously, the lower end face of the inner ring 12 and the lower end face of the needle roller 13 come into contact with the lower washer 15, and the upper end face of the inner ring 12 and the upper end face of the needle roller 13 separate from the upper washer 14, creating an axial gap (axial movement amount Ia). The axial movement amount Ia of the inner ring 12 needs to be an appropriate size considering mass production and proven performance.

[0043] To elaborate on the left-right tilt of the roller assembly 4 in Figure 11(d), for example, the axis 7x of the leg shaft 7 into which the lower right roller assembly 4(2) shown in Figure 8(b) is enclosed is due to the rotation of the outer joint member in the direction of the arrow. When the inner ring 12 of the roller assembly 4 moves relative to the leg axis 7 of the tripod member 3 As the leg shaft 7 pushes the inner ring 12 of the roller assembly 4(2) upward, a left-right tilt occurs due to counterclockwise rotation, and the upper end face of the inner ring 12 and the upper end face of the needle roller 13 come into contact with the upper washer 14, while the lower end face of the inner ring 12 and the lower end face of the needle roller 13 separate from the lower washer 15, creating an axial clearance (axial movement amount Ia).

[0044] The components of the roller assembly 4 of the tripod-type constant velocity universal joint 1 roll only slightly compared to a typical rolling bearing, but the relative movement of the components of the roller assembly 4 is significantly different and extremely harsh compared to a typical rolling bearing. Under these conditions, the vertical load when the inner ring 12 of the roller assembly 4 repeatedly moves relative to the leg shaft 7 of the tripod member 3 in the vertical direction causes the contact between the cylindrical outer surface 12b of the inner ring 12, the needle roller 13, and the cylindrical inner surface 11b of the roller 11 to repeatedly come into contact in an unbalanced direction. If an excessive load is applied in this state, edge stress will occur at the point of contact with the end face of the needle roller 13, which may lead to a reduced lifespan in some cases. We concluded that avoiding edge stress is an important technical issue.

[0045] Focusing on the technical issues described above, the target roller assembly 4' was examined to find specific internal specifications that take into account the relative movements of the components of the roller assembly 4. Figure 14 is an enlarged longitudinal cross-sectional view of the target roller assembly 4'. In Figure 14, the upper half above axis 4x is shown with the left end of the inner ring 12' and needle roller 13 in contact with the washer 15 and the right end away from the washer 14 (forming an axial displacement Ia), while the lower half below axis 4x is shown with the inner ring 12' and needle roller 13 positioned axially centered between the washers 14 and 15. At both ends of the inner ring 12', an axial displacement (Ia / 2) is formed that is bisected relative to the washers 14 and 15.

[0046] As shown in Figure 14, chamfered portions C are directly formed on both axial ends of the cylindrical outer surface 12b (straight portion S) of the inner ring 12', and the cylindrical outer surface 12b of the inner ring 12' and the chamfered portions C are connected at connection point Pi'. The end faces of the needle rollers 13 are flat. flat surface It has a specific shape and a rounded end face, and is connected to the cylindrical outer surface at a connection point Pr, similar to the needle-shaped roller 13 shown in Figure 12.

[0047] In roller assembly 4', with the lower end face (left end face) of the inner ring 12' and the lower end face (left end face) of the needle roller 13 in contact with the washer 15, the connection point Pr of the end face radius of the needle roller 13 almost coincides in the axial direction with the connection point Pi' of the cylindrical outer surface 12b of the inner ring 12. At the right end of Figure 12, due to the axial displacement Ia of the inner ring 12', the connection point Pr of the end face radius of the needle roller 13 is located axially inward from the connection point Pi' of the cylindrical outer surface 12b of the inner ring 12', i.e., within the cylindrical outer surface S of the inner ring 12'. Therefore, it was found that in the roller assembly 4' under consideration, if an excessive load is applied with bias to either the upper (right) or lower (left) side, edge stress due to contact between the end of the cylindrical outer surface S of the inner ring 12' and the end face radius of the needle roller 13 cannot be avoided. This result was key to arriving at new ideas and distinctive configurations for unique internal specifications that take into account the relative movement of the components of the roller assembly.

[0048] The characteristic configuration of this embodiment will be specifically described based on Figures 12, 13(a), and 13(b). Figure 12 is an enlarged longitudinal cross-sectional view of the roller assembly of this embodiment. Figure 13(a) is a partial longitudinal cross-sectional view showing the amount of axial movement of the inner ring within the roller assembly of this embodiment, and Figure 13(b) is an enlarged longitudinal cross-sectional view of section K in Figure 13(a). In the roller assembly 4 shown in Figure 12, the upper half above axis 4x is shown with the left end of the inner ring 12 and needle roller 13 in contact with the washer 15 and the right end separated from the washer 14 (an axial movement amount Ia is formed), and the lower half below axis 4x is shown with the inner ring 12 and needle roller 13 located in the axial center between the washers 14 and 15. At both ends of the inner ring 12, axial gaps (axial movement amount Ia / 2) are formed that are bisected relative to the washers 14 and 15.

[0049] As shown in Figure 12, the cylindrical outer surface 12b of the inner ring 12 consists of a straight section S and drop-shaped sections D at both ends in the axial direction. By connecting the straight section S and the drop-shaped sections D of the cylindrical outer surface 12b of the inner ring 12 tangentially, the increase in surface pressure can be suppressed. Furthermore, by integrally grinding the straight section S and the drop-shaped sections D of the cylindrical outer surface 12b of the inner ring 12, the increase in surface pressure can be suppressed with high precision. The drop shape can also be called a crowning shape. The drop amount of the drop-shaped section D is 1 to 5 μm, and by forming the drop-shaped section D by barrel machining, additional processing can be omitted and manufacturing costs can be reduced. As shown in Figures 12 and 13(b), the length of the drop-shaped section D in the axial direction of the inner ring 12 is Li. The drop-shaped section D is formed with an appropriate radius of curvature R and is connected tangentially to the straight section S of the cylindrical outer surface 12b of the inner ring 12 at connection point Pi. The end face of the needle roller 13 has a flat F-shaped end face, and an end face radius is formed, and it is connected to the cylindrical outer surface of the needle roller 13 at a connection point Pr.

[0050] An advantageous configuration of the present invention is that when the length of the drop-shaped portion D of the inner ring 12 in the axial direction is Li, the axial dimension of the end face radius of the needle roller 13 is r, and the amount of axial movement (axial clearance) of the inner ring 12 within the roller assembly 4 is Ia, the relationship Li > (Ia + r) is satisfied. As a result, when the lower end face of the inner ring 12 and the lower end face of the needle roller 13 are in contact with the washer 15, the connection point Pr of the end face radius of the needle roller 13 is located axially outward from the connection point Pi of the straight portion S of the cylindrical outer peripheral surface 12b of the inner ring 12, that is, at a position corresponding to the drop-shaped portion D. Furthermore, at the right end of Figure 12, due to the axial displacement Ia of the inner ring 12, the connection point Pi of the straight portion S on the cylindrical outer surface 12b of the inner ring 12 approaches the connection point Pr of the cylindrical outer surface of the needle roller 13. However, the connection point Pr of the needle roller 13 is located axially outward from the connection point Pi of the straight portion S on the cylindrical outer surface 12b of the inner ring 12, that is, at a position corresponding to the drop-shaped portion D. Conversely to Figures 13(a) and 13(b), when the upper end face of the inner ring 12 and the upper end face of the needle roller 13 each contact the washer 14, the connection point Pr of the needle roller 13 is similarly located axially outward from the connection point Pi of the straight portion S on the cylindrical outer surface 12b of the inner ring 12, that is, at a position corresponding to the drop-shaped portion D.

[0051] Therefore, by forming drop-shaped portions D at both axial ends of the cylindrical outer surface 12b of the inner ring 12, even if an excessive load is applied with bias to either the upper or lower side, the concentration of edge stress acting on the end face of the needle roller 13 in the roller assembly 4 is mitigated, improving durability and enabling smooth rotational operation. As an advantageous configuration, the relationship Li > (Ia + r) is satisfied, so the above effect can be maintained even if the inner ring and needle roller are biased to an unavoidable limit on either the upper or lower side due to cumulative machining accuracy and other factors.

[0052] Mass productionBased on past experience, the axial travel Ia of the inner ring 12 is approximately 0.53 mm, and the end face radius of the needle roller 13 is approximately 0.70 mm. Furthermore, the roller diameters φd of the needle roller 13 incorporated into the roller assembly 4 are typically 1.5 mm, 2 mm, and 2.5 mm. It will be done.

[0053] Figure 15 shows the case of circular contact. Figure 15 is a partial cross-sectional view showing a modified example in which the contact state between the roller and the roller guide surface of the first embodiment is a circular contact. In the case of circular contact, the roller guide surface 6 of the track groove 5 is formed in a partially cylindrical shape with a radius of curvature Rt', where the center of curvature ORt' is on a horizontal line XX passing through the intersection T of the center line 5x of the track groove 5 and the pitch circle PC of the track groove 5. The roller guide surface 6 and the roller 11 come into contact with the horizontal line XX passing through the intersection T. The circular contact case can be applied in the same way as the angular contact case.

[0054] A tripod-type constant velocity universal joint according to a second embodiment of the present invention will be described with reference to Figure 16. Figure 16 is a cross-sectional view of the tripod-type constant velocity universal joint of this embodiment. However, the two lower rollers and tripod members are not shown in cross-section, and the shaft is omitted from the illustration. This embodiment is a double-roller type tripod-type constant velocity universal joint, but the shape of the leg shaft and the shape of the roller assembly differ from the double-roller type tripod-type constant velocity universal joint 1 of the first embodiment. Parts having similar functions are denoted by the same reference numerals, and the key points will be explained.

[0055] As shown in Figure 16, in this embodiment, the tripod-type constant velocity universal joint 1 has a spherical outer surface 7a on the leg shaft 7 of the tripod member 3, and the inner ring 12 of the roller assembly 4 has a cylindrical inner surface 12a, with the cylindrical inner surface 12a of the inner ring 12 slidably enclosed on the spherical outer surface 7a of the leg shaft 7 of the tripod member 3. The outer surface 11a of the roller 11 is formed as an annular shape with a relatively small radius of curvature ro'', with its center of curvature at a position Or'' radially offset from the axis 7x of the leg shaft 7. The other configurations are the same as in the first embodiment, so the same reference numerals are used for parts with the same function, and the key points will be explained.

[0056] The roller assembly 4 is mainly composed of a roller 11, an inner ring 12, and a plurality of needle rollers 13 that are fully assembled between the roller 11 and the inner ring 12. The roller 11 has a cylindrical inner circumferential surface 11b. Washers 14 and 15 are fitted into the annular grooves of the cylindrical inner circumferential surface 11b of the roller 11 in an elastically reduced diameter state, and the roller assembly 4, consisting of the inner ring 12, needle rollers 13, and roller 11, is structured so that it does not separate due to the washers 14 and 15. The inner ring 12 has a cylindrical outer circumferential surface 12b, and drop-shaped portions D (not shown) are located at both axial ends of the cylindrical outer circumferential surface 12b. The roller assembly 4 is housed in the track groove 5 of the outer joint member 2, and the widthwise center of the roller assembly 4 (roller 11) is located on the pitch circle PC of the track groove 5.

[0057] The tripod member 3 has three radially projecting leg shafts 7. The outer circumferential surface 7a of the leg shafts 7 is formed in a spherical shape with its center of curvature on the axis 7x of the leg shafts 7, and the cylindrical inner circumferential surface 12a of the inner ring 12 of the roller assembly 4 is slidably enclosed within the spherical outer circumferential surface 7a. When the coupling takes an operating angle, the roller assembly 4 can be tilted with respect to the axis of the leg shafts 7 of the tripod member 3 and can move in the axial direction. Therefore, it is possible to avoid the rollers 11 and roller guide surfaces 6 of the roller assembly 4 being at an angle and to ensure correct rolling.

[0058] The roller guide surface 6 is formed on a horizontal line XX passing through the intersection T of the pitch circle PC of the track groove 5 and the center line 5x of the track groove 5, and is a relatively small partially cylindrical surface with a radius of curvature Rt" whose center of curvature is located at a position ORt" radially offset from the center line 5x of the track groove 5, and extends parallel to the axis of the joint. In this embodiment, a flange portion 5a is provided on one side of the track groove 5 as an example, but as shown in the modified example in Figure 17, a flange portion may not be provided on one side of the track groove 5.

[0059] Although not shown in the figures, the drop-shaped portions at both axial ends of the cylindrical outer surface of the inner ring have the following characteristic configuration (1) 、(2 ) is equipped with. (1) In a double-roller type tripod-type constant velocity universal joint, drop-shaped portions are formed at both axial ends of the cylindrical outer surface of the inner ring. (2) As an advantageous configuration, in a double-roller tripod type constant velocity universal joint, if the length of the drop-shaped portion of the inner ring in the axial direction is Li, the axial dimension of the end face radius of the needle roller is r, and the amount of axial movement of the inner ring within the roller assembly is Ia, then the relationship Li > (Ia + r) To satisfy.

[0060] The above characteristic configuration (1) 、(2) This allows for improved durability and smoother rotational operation in double-roller tripod-type constant-velocity universal joints by mitigating the concentration of edge stress acting on the end faces of the needle rollers in the roller assembly. Furthermore, cumulative machining precision ensures that the above effects are maintained even when the inner ring and needle rollers are unavoidably biased to either the upper or lower side. In addition, it enables proper dimensional setting of the drop-shaped section. The above characteristic configuration (1) 、(2) The details described for the tripod-type constant velocity universal joint of the first embodiment are the same for the tripod-type constant velocity universal joint of this embodiment and should be applied mutatis mutandis.

[0061] In the embodiments and modifications described above, examples were given in which the drop-shaped portion is formed on the cylindrical outer surface of the inner ring, but the invention is not limited to this, and the drop-shaped portion may also be formed on the cylindrical inner surface of the roller. Furthermore, the drop-shaped portion may be formed on both the inner ring and the roller.

[0062] The present invention is not limited in any way to the embodiments described above, and can be implemented in various other forms without departing from the spirit of the invention. The scope of the present invention is indicated by the claims, and includes all modifications within the meaning and scope of equivalents set forth in the claims. [Explanation of symbols]

[0063] 1. Tripod type constant velocity universal joint 2. Outer joint member 3. Tripod Member 4 Roller Assembly 5 Track grooves 5x Track groove centerline 6. Roller guide surface 7 Leg axis 7x Leg axis axis 11 Laura 11a Outer surface 11b Cylindrical inner surface 12 Inner Ring 12a Inner surface 12b Cylindrical outer surface 13 Needle-shaped roller Cr inner ring center Center of the Ct tripod member D Drop-shaped section Ia Axial displacement Li Drop-shaped section length Or center of curvature Or” center of curvature ORt center of curvature ORt' center of curvature ORt” center of curvature PC track groove pitch circle Rt radius of curvature Rt' radius of curvature Rt” radius of curvature S Straight section T intersection XX Horizontal line a long axis b Minor axis m gap r: Axial dimension of the end face radius ro radius of curvature ro” radius of curvature α contact angle β Left / Right tilt θ Working angle δ Track gap φd Roller diameter

Claims

1. A tripod-type constant velocity universal joint comprising: an outer joint member having three track grooves extending axially at three equally spaced positions in the circumferential direction of the inner circumference, and a roller guide surface arranged circumferentially opposite to the track grooves; a tripod member having three leg shafts projecting radially outward from the three equally spaced positions in the circumferential direction; and a roller assembly enclosed on the leg shafts, wherein the roller assembly comprises an inner ring enclosed on the leg shafts, a roller fitted onto the roller guide surface, a plurality of needle-shaped rollers arranged between the cylindrical outer surface of the inner ring and the cylindrical inner surface of the roller, and a pair of washers arranged on both axial sides of the needle-shaped rollers and the inner ring, with their outer edges attached to the inner circumference of the roller, A tripod-type constant velocity universal joint characterized by having drop-shaped portions made of crowning formed at both axial ends of the cylindrical outer surface of the inner ring.

2. The tripod-type constant velocity universal joint according to claim 1, characterized in that when Li is the length of the drop-shaped portion of the inner ring in the axial direction, r is the axial dimension of the end face radius of the needle roller, and Ia is the amount of axial movement of the inner ring within the roller assembly, the relationship Li > (Ia + r) is satisfied.

3. The tripod-type constant velocity universal joint according to claim 1 or 2, characterized in that the cylindrical outer surface of the inner ring and the drop-shaped portion are connected tangentially.

4. The tripod-type constant velocity universal joint according to any one of claims 1 to 3, characterized in that the inner surface of the inner ring is formed as an arc-shaped convex surface in the longitudinal cross-section of the inner ring, the outer surface of the leg shaft is straight in the longitudinal cross-section including the axis of the leg shaft and substantially elliptical in the cross-section perpendicular to the axis of the leg shaft, the outer surface of the leg shaft abuts the inner surface of the inner ring in a direction perpendicular to the axis of the joint and a gap is formed between it and the inner surface of the inner ring in the axial direction of the joint, and the roller is inclined within the track groove.

5. A tripod-type constant velocity universal joint according to any one of claims 1 to 4, characterized in that the roller and the roller guide surface make angular contact.

6. A tripod-type constant velocity universal joint according to any one of claims 1 to 4, characterized in that the roller and the roller guide surface are in circular contact.

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