constant velocity joint of the three-bar design

Abstract

A groove-orthogonal cross-sectional shape of a cover surface (13) of a raceway groove (10) of an outer ring (2) of a constant velocity joint of tripod design (1) is a line shape which has at least a part of a target contour line (OL1a, OL2a, OL3a) which is arranged away from a central axis of the outer ring (2) in a contour line (OL1, OL2, OL3) which is obtained by projecting a roller end surface (32) in an axial direction of the outer ring (2) when a roller (4) is inclined by a predetermined angle (θp2).

Description

TECHNICAL AREA

[0001] The present disclosure relates to a constant velocity joint of the tripod design. STATE OF THE ART

[0002] In a constant velocity joint of the tripod design, as described in patent document 1, an outer ring has raceway grooves in which rollers roll. The groove-orthogonal cross-sectional shape (cross-sectional shape orthogonal to the groove) of the top surface (groove bottom surface) of the outer ring's raceway groove is formed in a circular arc shape centered on a central axis of the outer ring. State-of-the-art documents, patent documents

[0003] Patent document 1: Unexamined Japanese patent application disclosure no. 2004-257569 (JP 2004-257569 A) SUMMARY OF THE INVENTION Problem that the invention is intended to solve

[0004] When the roller in a tripod-type constant velocity joint comes into contact with the top surface of the outer ring's raceway groove during a tilting (tilting) movement, friction is generated. This friction causes a force / constraint force that induces an oscillation in the tripod-type constant velocity joint. If the groove-orthogonal cross-sectional shape of the top surface of the outer ring's raceway groove is formed in a circular arc shape centered on the outer ring's central axis, as in the tripod-type constant velocity joint described in patent document 1, it is possible to prevent the roller from contacting the top surface of the outer ring's raceway groove during tilting (tilting).

[0005] However, if the roller tilts or is tilted, a gap exists between the roller and the top surface of the outer ring's raceway groove. Therefore, there is potential for improvement in terms of reducing the size and weight of the outer ring.

[0006] The present disclosure was made with regard to such a problem and provides a constant velocity joint of the tripod design which can achieve a reduction in the size and weight of an outer ring. facility to solve the problem

[0007] One aspect of the present disclosure is a constant velocity joint of the tripod design, comprising an outer ring with a plurality of raceway grooves extending in an axial direction, a tripod with a plurality of tripod shaft sections extending radially outward, and rollers fitted externally onto the tripod shaft sections and configured to roll in the raceway grooves. The raceway groove has a first raceway surface forming a groove side surface, a second raceway surface forming another groove side surface, and a top surface forming a groove bottom surface. The roller has a roller outer circumferential surface configured to roll on the first raceway surface or the second raceway surface, and a roller end surface that is an axial end surface of the roller and faces the top surface.A groove-orthogonal cross-sectional shape (cross-sectional shape orthogonal to the groove) of the top surface is a line shape that has at least part of a target contour line located away from a central axis of the outer ring in a contour line obtained by projecting the roller end surface in the axial direction of the outer ring when the roller is inclined or tilted by a predetermined angle. Effects of the invention

[0008] In the constant velocity joint of the tripod design of the above point, the groove-orthogonal cross-sectional shape of the top surface of the outer ring's raceway groove is the line shape that exhibits at least a portion of the target contour line. The target contour line is a line located away from the central axis of the outer ring in the contour line obtained by projecting the roller end face in the axial direction of the outer ring when the roller tilts (lean, is inclined) by the predetermined angle.

[0009] This means that when the roller tilts (lean) by the predetermined angle, part of the roller end face comes into contact with the top surface of the outer ring's raceway groove. If the roller tilts (is tilted) by a smaller angle than the predetermined angle, a small gap exists between the top surface and the roller. Therefore, the generation of the force / constraint force can be prevented if the roller tilts (lean) by an angle smaller than the predetermined angle.

[0010] When the roller tilts through the predetermined angle, part of the roller comes into contact with the cover surface, meaning the cover surface is positioned closer to the center of the outer ring compared to a case where the groove-orthogonal cross-sectional shape of the cover surface is a circular arc centered on the outer ring's central axis. This allows for a reduction in the size of the outer ring and, consequently, a reduction in its weight. Furthermore, the size and weight of the tripod-type constant velocity joint can be reduced.

[0011] As described above, it is possible, from the above point of view, to provide the constant velocity joint of the tripod design, which can achieve a reduction in the size and weight of the outer ring.

[0012] Reference numerals in parentheses in the claims represent the corresponding relationships to specific devices described in the embodiments described below and are not intended to limit the technical scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a diagram of a constant velocity joint of tripod design of a first embodiment from a view in an axial direction, showing a case in which a joint angle is 0° and only shows a section of a raceway groove of an outer ring. Fig. 2 is a sectional view along a line II-II in Fig. 1 and is an axial partial sectional view of the constant velocity joint of the tripod design. Fig. 3 is a sectional view along a line III-III in Fig. 2 and is a radial partial sectional view of the constant velocity joint of the tripod design. Fig. Figure 4 is a partial view of the constant velocity joint of the tripod design from the axial direction, when the joint angle θp1 is and a roller tilts (tilts) or is inclined by a tilting angle (inclination angle) θp1. Fig. 5 is a section view along a line VV in Fig. 4 and is an axial partial sectional view of the constant velocity joint of the tripod design when the joint angle θp1 is. Fig. Figure 6 is an axial partial sectional view of the constant velocity joint of the tripod design, when the joint angle is θp2 and the roller tilts or is inclined by a tilt angle (inclination angle) θp2. Fig. Figure 7 is a diagram showing only the outer ring and the roller from the perspective of a left side. Fig. 6, that is, in the axial direction of the outer ring. Fig. Figure 8 is a diagram showing a groove-orthogonal cross-sectional shape (cross-sectional shape orthogonal to the groove) of a cover surface of the raceway groove of the outer ring, wherein (a) is a diagram showing a contour line OL1, (b) is a diagram showing a target contour line OL1a, and (c) is a diagram showing the groove-orthogonal cross-sectional shape of the cover surface of the raceway groove of the outer ring. Fig. Figure 9 is a diagram illustrating the shape of the top surface of the raceway groove of the outer ring according to a modification of the first embodiment. Fig. Figure 10 is a diagram showing a groove-orthogonal cross-sectional shape of a cover surface of a raceway groove of an outer ring forming a constant velocity joint of the tripod design of a second embodiment, wherein (a) is a diagram showing a first contour line OL2 and a first target contour line OL2a in a state in which a roller is in contact with a first raceway surface, (b) is a diagram showing a second contour line OL3 and a second target contour line OL3a in a state in which the roller is in contact with a second raceway surface, (c) is a diagram showing the shape lines OL2a, OL3a, OL4 in a target area, and (d) is a diagram showing the groove-orthogonal cross-sectional shape of the cover surface of the raceway groove of the outer ring. Fig. Figure 11 is a diagram illustrating the shape of the top surface of the raceway groove of the outer ring according to a modification of the second embodiment. FORMS FOR IMPLEMENTING THE INVENTION (First embodiment) 1. Design of a constant velocity joint of tripod design 1

[0013] The design of a constant velocity joint 1 of the present embodiment is described with reference to Fig. 1 to 3 are described. The constant velocity joint 1 of the tripod design is used, for example, in a drive shaft or cardan shaft of a vehicle. The constant velocity joint of the tripod design 1 has an outer ring 2, a tripod 3 and rollers (rolling elements) 4.

[0014] The outer ring 2 is designed in a tubular shape with a base and has three raceway grooves 10 extending axially along its inner circumferential surface. The three raceway grooves 10 are positioned at equal intervals along the circumference. Fig. Figures 1 to 3 show only one raceway groove 10. In the following description, a groove-orthogonal cross-section (cross-section orthogonal to the groove) is a cross-section orthogonal to the direction in which the raceway groove 10 extends, and a groove-direction cross-section is a cross-section in the direction in which the raceway groove 10 extends. A line that is orthogonal to a central axis Lo of the outer ring 2 and passes through the center of the raceway groove 10 in a direction corresponding to the groove width is defined as a raceway groove centerline Lg.

[0015] The raceway groove 10 has a first raceway surface 11, which forms one side surface of the groove, and a second raceway surface 12, which forms the other side surface of the groove. The first raceway surface 11 and the second raceway surface 12 face each other. The groove-orthogonal cross-sectional shape (cross-sectional shape orthogonal to the groove) of the first raceway surface 11 and the second raceway surface 12 is a curved concave shape in the groove-orthogonal cross-section of the raceway groove 10. The groove-orthogonal cross-sectional shape of the first raceway surface 11 and the second raceway surface 12 is, for example, a Gothic arch shape in which two circular arcs are joined.

[0016] The raceway groove 10 further comprises a top surface 13, which forms a groove bottom surface. The detailed shape of the top surface 13 is described below. In the present embodiment, the raceway groove 10 has a first recessed surface 14 and a second recessed surface 15. The first recessed surface 14 is a section connecting the first raceway surface 11 and the top surface 13 and is positioned at one corner section of the groove bottom. The second recessed surface 15 is a section connecting the second raceway surface 12 and the top surface 13 and is positioned at the other corner section of the groove bottom. The groove-orthogonal cross-sectional shape of each of the first recessed surface 14 and the second recessed surface 15 is a curved concave shape with a smaller radius of curvature than that of the first raceway surface 11, the second raceway surface 12, and the top surface 13.

[0017] The tripod 3 is a component attached to a shaft (not shown) and forms an internal component that is received in the outer ring 2. The tripod 3 has a hub section 21 and three tripod shaft sections 22. The hub section 21 is formed in a raw shape and has a splined shaft formed on its inner circumferential surface so that it can be fitted (fastened) onto the shaft.

[0018] The tripod shaft section 22 is a shaft component that extends radially outwards from the outer circumferential surface of the hub section 21. The tripod shaft section 22 is formed in a columnar shape, a spherical shape, etc. The columnar tripod shaft section 22 can, for example, have a circular column shape, an elliptical column shape, or a composite column shape in which part of a circular or elliptical column is formed in a planar shape. In the present embodiment, the cross-sectional shape of the column of the tripod shaft section 22 has a pair of convexly curved sections that form an ellipse and straight sections that connect the convexly curved sections.

[0019] The roller 4 is fitted externally onto the tripod shaft section 22 and is axially slidable within the tripod shaft section 22. The roller 4 rolls in the raceway groove 10 of the outer ring 2 while being fitted externally into the tripod shaft section 22. When a torque is transmitted between the roller 4 and the first raceway surface 11, the roller 4 rolls on the first raceway surface 11. When a torque is transmitted between the roller 4 and the second raceway surface 12, the roller 4 rolls on the second raceway surface 12.

[0020] As in Fig. 1 and Fig. As shown in Figure 2, the outer shape of the roller 4 has a roller outer circumferential surface 31, a roller end surface 32, and a roller base surface 33. The roller outer circumferential surface 31 is designed to roll on the first raceway surface 11 or the second raceway surface 12. The roller outer circumferential surface 31 is, for example, formed in a spherical shape centered at a point on a central axis Lr of the roller 4.

[0021] The roller end surface 32 is one of the axial end surfaces of the roller 4, facing the ceiling surface 13. In the present embodiment, the roller end surface 32 has a circular flat section 32a and a chamfered section 32b. The circular flat section 32a is formed in a disk-like shape, centered on the central axis Lr of the roller 4 and parallel to a plane that is orthogonal to the axis of the roller 4. The chamfered section 32b is a surface that connects the outer circumferential edge of the circular flat section 32a and the outer circumferential surface 31 of the roller, and is formed in a partially conical shape that is inclined orthogonal to the axis of the roller 4 with respect to the plane.

[0022] The roller base surface 33 is one of the axial end surfaces of the roller 4, opposite the roller end surface 32. In the present embodiment, the roller base surface 33 is formed in a planar, symmetrical shape with respect to the roller end surface 32. The roller base surface 33 has a circular flat section 33a and a chamfered section 33b. The circular flat section 33a is formed in a disk-like shape, centered on the central axis Lr of the roller 4 and running parallel to the plane and orthogonal to the axis of the roller 4. The chamfered section 33b is a surface connecting the outer circumferential edge of the circular flat section 33a and the outer circumferential surface 31 of the roller, and is formed in a partially conical shape, inclined orthogonal to the axis of the roller 4 with respect to the plane.

[0023] The roller 4 can be configured as either a single roller or a double roller. For example, the single roller design has an outer roller and a plurality of needle bearings arranged between the outer circumferential surface of the tripod shaft section 22 and the inner circumferential surface of the outer roller. The double roller design has an outer roller, an inner roller, and a plurality of needle bearings arranged between the outer and inner rollers. The roller 4 can be tiltable or non-tiltable with respect to the tripod shaft section 22.

[0024] In the present embodiment, roller 4 is a double roller design, as in Fig. Figure 3 shows the roller 4 having an outer roller 41, an inner roller 42, a plurality of needle bearings 43 and snap rings 44, 45. The outer circumferential surface of the outer roller 41 is designed so that it rolls on the first raceway surface 11 and the second raceway surface 12.

[0025] The axial cross-sectional shape of the inner circumferential surface of the inner roller 42 is, for example, a curved shape that is radially convex inwards. The inner roller 42 is fitted externally onto the outer circumferential surface of the tripod shaft section 22 and is tiltable (adjustable) relative to the tripod shaft section 22. The plurality of needle bearings 43 is arranged between the inner circumferential surface of the outer roller 41 and the outer circumferential surface of the inner roller 42. The snap rings 44, 45 are locked to the outer roller 41 and engage with the inner roller 42 and the plurality of needle bearings 43 to position the inner roller 42 and the plurality of needle bearings 43. 2. Operation of the constant velocity joint of the tripod design 1

[0026] The operation of the constant velocity joint of tripod design 1 is described with reference to Fig. 4 and Fig. 5 described. As in Fig. 4 and Fig. As shown in Figure 5, the angle between the central axis Lo of the outer ring 2 and the central axis of the tripod 3 is a joint angle. If the central axis Lr of the roller 4 coincides with the central axis of the tripod shaft section 22, the angle between a raceway groove centerline Lg and the central axis Lr of the roller 4 is equal to the joint angle. Fig. 4 and Fig. Figure 5 shows a state in which the joint angle is θp1.

[0027] When the joint angle θp1 is and the constant velocity joint of tripod design 1 rotates, a torque is transmitted between the outer ring 2 and the tripod 3 via the roller 4. At this time, the roller 4 rolls on the first raceway surface 11 or the second raceway surface 12 and moves back and forth in the raceway groove 10 while tilting (inclining) with respect to the raceway groove 10.

[0028] The maximum joint angle φ1 of the constant velocity joint of tripod design 1 during straight-line travel of the vehicle at a constant speed is an angle that lies in a range of, for example, 4 to 10°. The maximum joint angle φ2 of the constant velocity joint of tripod design 1 during acceleration or deceleration of the straight-line vehicle can have a larger angular range than that of the maximum joint angle φ1. The maximum joint angle φ2 encompasses a range of, for example, 6 to 20°. The maximum joint angle φ3 of the constant velocity joint of tripod design 1 during maximum steering can have a larger angular range than that of the maximum joint angles φ1 and φ2. The maximum joint angle φ3 encompasses a range of, for example, 10 to 25°. 3. Outline of the groove-orthogonal cross-sectional shape of the ceiling surface 13

[0029] The outline of the groove-orthogonal cross-sectional shape of the ceiling surface 13 of the raceway groove 10 of the outer ring 2 is defined with reference to Fig. 6 and Fig. 7 described. The groove-orthogonal cross-sectional shape of the ceiling surface 13 is determined by using the shape of the roller 4 when the roller 4 is tilted (inclined) by a predetermined angle θp2, as described in Fig. Figure 6 is shown. When the roller 4 tilts by the predetermined angle θp2, the roller 4 appears from the perspective in the axial direction of the outer ring 2 as shown in Figure 6. Fig. Figure 7 shows that the predetermined angle θp2 is a contact tilt angle. This means that the roller 4 can come into contact with the ceiling surface 13 when the roller 4 tilts by the predetermined angle θp2.

[0030] The predetermined angle θp2 can be one of two types of angle. A first predetermined angle θp2 is set to an angle that is greater than the maximum joint angle φ1 while the vehicle is traveling straight ahead at a constant speed and that is equal to or less than the maximum joint angle φ2 while the vehicle is accelerating or decelerating. In this case, the first predetermined angle θp2 is naturally a smaller angle than the maximum joint angle φ3 at maximum steering.

[0031] In this case, roller 4 does not contact the ceiling surface 13 if the tilt angle (incline angle) of roller 4 is the maximum articulation angle φ1 while the vehicle is traveling straight ahead at a constant speed. Roller 4 does contact the ceiling surface 13 if the tilt angle of roller 4 is the maximum articulation angle φ2 while the vehicle is accelerating or decelerating. If the tilt angle of roller 4 is changed to increase, roller 4 will contact the ceiling surface 13 within the range where the tilt angle of roller 4 is greater than φ1 and equal to or less than φ2.

[0032] A second predetermined angle θp2 is set to an angle that is greater than the maximum joint angle φ2 during acceleration or deceleration of the straight-ahead vehicle and equal to or less than the maximum joint angle φ3 during maximum steering. In this case, the second predetermined angle θp2 is naturally an angle greater than the maximum joint angle φ1 during straight-ahead travel of the vehicle at a constant speed.

[0033] In this case, roller 4 does not contact the ceiling surface 13 if its tilt angle during straight-ahead travel at a constant speed is equal to the maximum articulation angle φ1. Furthermore, roller 4 does not contact the ceiling surface 13 if its tilt angle is equal to the maximum articulation angle φ2 during acceleration or deceleration of the straight-ahead vehicle. Roller 4 does contact the ceiling surface 13 if its tilt angle is equal to the maximum articulation angle φ3 during maximum steering. If the tilt angle of roller 4 is changed to increase, roller 4 will contact the ceiling surface 13 within the range where its tilt angle is greater than φ2 and equal to or less than φ3.

[0034] When roller 4 is not in contact with the ceiling surface 13, a gap exists between roller 4 and the ceiling surface 13. Therefore, by increasing the range of the tilt angle in which roller 4 is not in contact with the ceiling surface 13, the generation of a force / constraint force in the area where roller 4 reaches a large tilt angle can be more effectively prevented. As the tilt angle in which roller 4 is not in contact with the ceiling surface 13 increases, the size of the outer ring 2 also increases. Therefore, the range of the tilt angle in which roller 4 is not in contact with the ceiling surface 13 is not excessively increased, and the area in which the generation of the force / constraint force can be prevented is minimized. In this way, the effects of reducing and preventing the force / constraint force can be achieved. 4. Details of the groove-orthogonal cross-sectional shape of the ceiling surface 13

[0035] Details of the groove-orthogonal cross-sectional shape of the ceiling surface 13 are given with reference to Fig. 8 described. As in Fig. As shown in Figure 8(a), a contour line OL1, obtained by projecting the roller end surface 32 in the axial direction of the outer ring 2 when the roller 4 tilts by the predetermined angle θp2, has a shape indicated by a thick continuous line. In the present embodiment, part of the contour line OL1 is defined by a boundary line between the circular flat section 32a and the chamfered section 32b, and the other part of the contour line OL1 is defined by a boundary line between the chamfered section 32b and the roller outer circumferential surface 31. Fig. 8(a) H13 is an area of ​​the ceiling surface 13.

[0036] In Fig. 8(b) is a target contour line OL1a, located at a distance from the central axis Lo of the outer ring 2 in contour line OL1 within area H13 of the ceiling surface 13, indicated by a thick continuous line. The target contour line OL1a passes through a central highest point P1, located on the central axis Lr of the roller 4 on contour line OL1. Furthermore, the target contour line OL1a is a line connecting one endpoint P2 and the other endpoint P3, located at both ends of area H13 of the ceiling surface 13. That is, the target contour line OL1a is defined by a line shape connecting the central highest point P1 and one endpoint P2, and by a line shape connecting the central highest point P1 and the other endpoint P3.

[0037] As in Fig. As shown in Figure 8(c), the groove-orthogonal cross-sectional shape of the ceiling surface 13 is a linear shape that has at least part of the target contour line OL1a. In the present embodiment, the groove-orthogonal cross-sectional shape of the ceiling surface 13 is a linear shape that has the entire target contour line OL1a. In the groove-orthogonal cross-sectional shape of the ceiling surface 13 in Fig. 8(c) if a point P11 coincides with the central highest point P1, a point P12 coincides with one endpoint P2 and a point P13 coincides with the other endpoint P3. 5. Effects

[0038] In the constant velocity joint 1 of the tripod design of the present embodiment, the groove-orthogonal cross-sectional shape of the cover surface 13 of the raceway groove 10 of the outer ring 2 is the line shape that has at least a part of the target contour line OL1a. The target contour line OL1a is a line in the contour line OL1 located away from the central axis Lo of the outer ring 2, which is obtained by projecting the roller end surface 32 in the axial direction of the outer ring 2 when the roller 4 tilts by the predetermined angle θp2.

[0039] This means that when roller 4 tilts by the predetermined angle θp2, part of the roller end face 32 comes into contact with the top surface 13 of the raceway groove 10 of the outer ring 2. If roller 4 tilts by an angle smaller than the predetermined angle θp2, a small gap exists between the top surface 13 and roller 4. Thus, the generation of the force / constraint force can be prevented when roller 4 tilts by an angle smaller than the predetermined angle θp2.

[0040] When roller 4 is inclined (tilted) by the predetermined angle θp2, part of roller 4 comes into contact with the cover surface 13. This means that the cover surface 13 is positioned closer to the center of the outer ring 2 compared to a case where the groove-orthogonal cross-sectional shape of the cover surface 13 is a circular arc centered on the central axis Lo of the outer ring 2. This allows the size of the outer ring 2 to be reduced, and consequently, its weight can be reduced. Furthermore, the size and weight of the constant velocity joint of tripod design 1 can be reduced. (Modification of the first embodiment)

[0041] A modification of the first embodiment is described with reference to Fig. 9 described. In the first embodiment, the groove-orthogonal cross-sectional shape of the ceiling surface 13 is the line shape that completely coincides with the target contour line OL1a. Alternatively, the groove-orthogonal cross-sectional shape of the ceiling surface 13 can be a line shape that only partially coincides with the target contour line OL1a.

[0042] Fig. 9 shows the in Fig. 8(b) Target contour line OL1a is shown. A line shape that has a predetermined distance ΔC from the target contour line OL1a is indicated by a dashed line. The groove-orthogonal cross-sectional shape of the ceiling surface 13 can be a line shape that lies within a region of the predetermined distance ΔC from the target contour line OL1a. For example, the groove-orthogonal cross-sectional shape of the ceiling surface 13 is defined by a line shape that connects points P1 and P2 by an ellipse or a circular arc, and also by a line shape that connects points P1 and P3 by an ellipse or a circular arc within the region of the predetermined distance ΔC.

[0043] If the groove-orthogonal cross-sectional shape of the ceiling surface 13 is a linear shape that lies within the area of ​​the predetermined gap ΔC from the target contour line OL1a, the groove-orthogonal cross-sectional shape of the ceiling surface 13 can be a shape that facilitates forming (manufacturing). In particular, if the groove-orthogonal cross-sectional shape of the ceiling surface 13 is a linear shape that passes through points P1, P2, P3 within the area of ​​the predetermined gap ΔC, the size and weight of the outer ring 2 can be reduced. (Second embodiment)

[0044] The groove-orthogonal cross-sectional shape of a ceiling surface 13 of a constant velocity joint of tripod design type 1 of a second embodiment is defined with reference to Fig. 10 described. To simplify the description, the difference between the opposite distance between the first raceway surface 11 and the second raceway surface 12 and the width of the outer circumferential surface 31 of the roller is shown in Fig. 10 exaggerated. In fact, the difference between the opposite distance between the first raceway surface 11 and the second raceway surface 12 and the width of the outer circumferential surface 31 of the roller is very small.

[0045] As in Fig. As shown in Figure 10(a), a torque is transmitted between the roller 4 and the first raceway surface 11. Fig. 10(a) has a first contour line OL2, which is obtained by projecting the roller end surface 32 in the axial direction of the outer ring 2 when the roller 4 is inclined by the predetermined angle θp2 and the roller outer circumferential surface 31 comes into contact with the first raceway surface 11 and has a gap to the second raceway surface 12, a shape which is indicated by a continuous line.

[0046] As in Fig. As shown in Figure 10(a), a first target contour line OL2a, located a distance from the central axis Lo of the outer ring 2 and closer to the first raceway surface 11 with respect to the central axis Lr of the roller 4 in the first contour line OL2 within the area H13 of the top surface 13, is indicated by a thick continuous line. The first target contour line OL2a is defined by a line shape connecting a first central highest point P21, located on the central axis Lr of the roller 4, and an endpoint P22 of the area H13 of the top surface 13 in the first contour line OL2.

[0047] As in Fig. As shown in Figure 10(b), a torque is transmitted between the roller 4 and the second raceway surface 12. Fig. 10(b) has a second contour line OL3, which is obtained by projecting the roller end surface 32 in the axial direction of the outer ring 2 when the roller 4 tilts by the predetermined angle θp2 and the roller outer circumferential surface 31 comes into contact with the second raceway surface 12 and has a gap to the first raceway surface 11, a shape which is indicated by a continuous line.

[0048] As in Fig. As shown in Figure 10(b), a second target contour line OL3a, located further away from the central axis Lo of the outer ring 2 and closer to the second raceway surface 12 with respect to the central axis Lr of the roller 4 in the second contour line OL3 within the area H13 of the top surface 13, is indicated by a thick continuous line. The second target contour line OL3a is defined by a line shape connecting a second central highest point P31, located on the central axis Lr of the roller 4, and the other endpoint P32 of the area H13 of the top surface 13 in the second contour line OL3.

[0049] As in Fig. Figure 10(c) shows a straight shape that connects the first target contour line OL2a and the second target contour line OL3a by a straight line, represented by OL4. That is, the straight shape OL4 is a straight line that connects the first central highest point P21, which serves as the endpoint of the first target contour line OL2a, and the second central highest point P31, which serves as the endpoint of the second target contour line OL3a.

[0050] As in Fig. As shown in Figure 10(d), the groove-orthogonal cross-sectional shape of the ceiling surface 13 is defined by a line shape that includes at least part of the first target contour line OL2a and a line shape that includes the second target contour line OL3a. In the present embodiment, the groove-orthogonal cross-sectional shape of the ceiling surface 13 is additionally defined by the straight shape OL4, in addition to a line shape that includes the entire first target contour line OL2a and a line shape that includes the second target contour line OL3a.

[0051] In the groove-orthogonal cross-sectional shape of the ceiling surface 13 in Fig. In 10(d), a point P41 coincides with the first central highest point P21 of the first target contour line OL2a, and a point P41 coincides with the endpoint P22 of the first target contour line OL2a. A first ceiling surface section 13a, which is part of the ceiling surface 13, coincides with the first target contour line OL2a. In the groove-orthogonal cross-sectional shape of the ceiling surface 13, a point P51 coincides with the second central highest point P31 of the second target contour line OL3a, and a point P51 coincides with the endpoint P32 of the second target contour line OL3a. A second ceiling surface section 13b, which is part of the ceiling surface 13, coincides with the second target contour line OL3a. A third ceiling surface section 13c, which is part of the ceiling surface 13, coincides with the straight shape OL4.

[0052] According to the present embodiment, if the outer circumferential surface of the roller 31 is in contact with one of the first raceway surfaces 11 and the second raceway surface 12 and has a gap between them, the groove-orthogonal cross-sectional shape of the cover surface 13 can be determined by taking the gap into account. This makes it possible to reduce the size and weight of the outer ring 2 by taking the gap into account. (Modification of the second embodiment)

[0053] A modification of the second embodiment is described with reference to Fig. 11 described. In the second embodiment, the groove-orthogonal cross-sectional shape of the ceiling surface 13 is the line shape that completely coincides with the first target contour line OL2a, the second target contour line OL3a, and the straight shape OL4. Alternatively, the groove-orthogonal cross-sectional shape of the ceiling surface 13 can be a line shape that only partially coincides with the first target contour line OL2a and the second target contour line OL3a.

[0054] Fig. Figure 11 shows the first target contour line OL2a, the second target contour line OL3a, and the straight shape OL4, as in Fig.Figure 10(c) shows a line shape that has a predetermined distance ΔC from the first target contour line OL2a, the second target contour line OL3a, and the straight shape OL4, indicated by a dashed line. The groove-orthogonal cross-sectional shape of the ceiling surface 13 can be a line shape that lies within a region of the predetermined distance ΔC from the first target contour line OL2a, the second target contour line OL3a, and the straight shape OL4.

[0055] For example, the groove-orthogonal cross-sectional shape of the ceiling surface 13 is defined by a line shape connecting points P21 and P22 by an ellipse or a circular arc, and further by a line shape connecting points P31 and P32 by an ellipse or a circular arc within the area of ​​the predetermined gap ΔC. The groove-orthogonal cross-sectional shape of the ceiling surface 13 corresponds to the straight shape OL4.

[0056] If the groove-orthogonal cross-sectional shape of the ceiling surface 13 is the linear shape described above, it can be a shape that facilitates forming (manufacturing). In particular, if the groove-orthogonal cross-sectional shape of the ceiling surface 13 is a linear shape that passes through points P21, P22, P31, P32 within the area of ​​the predetermined gap ΔC, the size and weight of the outer ring 2 can be reduced. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2004-257569

[0003] JP 2004-257569 A

[0003]

Claims

[1] Constant velocity joint of the tripod type (1), comprising: an outer ring (2) having a plurality of raceway grooves (10) extending in an axial direction; a tripod (3) having a plurality of tripod shaft sections (22) extending radially outward; and Rollers (4) fitted externally onto the tripod shaft sections and designed to roll in the raceway grooves, wherein: the raceway groove has a first raceway surface (11) forming a groove side surface, a second raceway surface (12) forming another groove side surface, and a ceiling surface (13) forming a groove bottom surface; the role has the following: a roller outer peripheral surface (31) designed to roll on the first raceway surface or the second raceway surface, and a roller end surface (32) which is an axial end surface of the roller facing the ceiling surface; and a groove-orthogonal cross-sectional shape of the ceiling surface is a line shape including at least a part of a target contour line (OL1a, OL2a, OL3a) located away from a center axis of the outer ring in a contour line (OL1, OL2, OL3) obtained by projecting the roller end surface in the axial direction of the outer ring when the roller is inclined by a predetermined angle (θp2). [2] A tripod type constant velocity joint according to claim 1, wherein the groove-orthogonal cross-sectional shape of the ceiling surface is a line shape encompassed within a range of a predetermined gap (ΔC) from the target contour line. [3] A tripod type constant velocity joint according to claim 1 or 2, wherein: the contour line (OL2, OL3) has the following: a first contour line (OL2) obtained by projecting the roller end surface in the axial direction of the outer ring when the roller is inclined by the predetermined angle and the roller outer peripheral surface comes into contact with the first raceway surface and has a gap from the second raceway surface, and a second contour line (OL3) obtained by projecting the roller end surface in the axial direction of the outer ring when the roller is inclined by the predetermined angle and the roller outer peripheral surface comes into contact with the second raceway surface and has a gap from the first raceway surface; and the groove-orthogonal cross-sectional shape of the ceiling surface is defined by a line shape having at least a part of a first target contour line (OL2a) located away from the center axis of the outer ring and closer to the first raceway surface with respect to a center axis of the roller in the first contour line, and a line shape having at least a part of a second target contour line (OL3a) located away from the center axis of the outer ring and closer to the second raceway surface with respect to the center axis of the roller in the second contour line. [4] A tripod type constant velocity joint according to claim 3, wherein the groove-orthogonal cross-sectional shape of the ceiling surface is defined by a line shape included within a range of a predetermined gap (ΔC) from the first target contour line and a line shape included within a range of the predetermined gap (ΔC) from the second target contour line. [5] A tripod type constant velocity joint according to claim 3 or 4, wherein the groove-orthogonal cross-sectional shape of the ceiling surface is further defined by a straight shape (OL4) connecting the first target contour line and the second target contour line by a straight line. [6] A tripod type constant velocity joint according to any one of claims 1 to 5, wherein the predetermined angle is an angle larger than a maximum joint angle (φ1) of the tripod type constant velocity joint during straight travel of a vehicle at a constant speed. [7] A tripod type constant velocity joint according to claim 6, wherein the maximum joint angle (φ1) of the tripod type constant velocity joint during straight running of the vehicle at the constant speed is an angle in a range of 4 to 10°. [8] A tripod type constant velocity joint according to claim 6 or 7, wherein the predetermined angle is an angle larger than a maximum joint angle (φ2) of the tripod type constant velocity joint during acceleration or deceleration of the straight-running vehicle. [9] A tripod type constant velocity joint according to claim 6 or 7, wherein the predetermined angle is an angle equal to or smaller than a maximum joint angle (φ2) of the tripod type constant velocity joint during acceleration or deceleration of the straight-running vehicle. [10] A tripod type constant velocity joint according to claim 8 or 9, wherein the maximum joint angle (φ2) of the tripod type constant velocity joint during acceleration or deceleration of the straight-ahead vehicle is an angle in a range of 6 to 20°. [11] A tripod type constant velocity joint according to any one of claims 1 to 10, wherein the predetermined angle is an angle smaller than a maximum joint angle (φ3) of the tripod type constant velocity joint during maximum steering. [12] A tripod type constant velocity joint according to claim 11, wherein the maximum joint angle (φ3) of the tripod type constant velocity joint during maximum steering is an angle in a range of 10 to 25°. [13] A tripod type constant velocity joint according to any one of claims 1 to 12, wherein the raceway groove includes the first raceway surface, the second raceway surface, the ceiling surface, a first recessed surface (14) connecting the first raceway surface and the ceiling surface, and a second recessed surface (15) connecting the second raceway surface and the ceiling surface. [14] A tripod type constant velocity joint according to any one of claims 1 to 13, wherein the roller is fitted externally to the tripod shaft portion such that the roller is tiltable with respect to the tripod shaft portion.

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