JP2008281182A - Tripod type constant velocity universal joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tripod type constant velocity universal joint for reducing contact bearing pressure, while rolling a roller in parallel to a track groove, in a single roller type of a simple structure. <P>SOLUTION: In this tripod type constant velocity universal joint, a bus bar of an outer peripheral surface 28 of a trunnion journal 26 is formed as a circular arc having the curvature center in a position offset to distant side from the center line of the trunnion journal 26, and an inner peripheral surface shape of a roller 32 is formed as a convex circular arc surface having the same radius of curvature as the bus bar of the trunnion journal 26. A hand drum-shaped roller 40 having the same curvature as these surfaces, is arranged between the outer peripheral surface 28 of the trunnion journal 26 and an inner peripheral surface 36 of the roller 32. Abutting surfaces abutting on each other are arranged on at least the joint axis side out of an end part of the inner peripheral surface of the roller and an end part of the roller. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a tripod type constant velocity universal joint, and can be used for power transmission devices such as automobiles and various industrial machines.

In order to solve the vehicle shudder caused by the third-order induced thrust of the tripod type constant velocity universal joint, as shown schematically in FIGS. 16 and 17, the double roller in which the outer roller rolls in parallel with the track groove of the outer ring. A roller type tripod type constant velocity universal joint is known (see, for example, Patent Document 1 and Patent Document 2). In this type, the roller guide surface formed on the side wall of the track groove has a Gothic arch shape, so that the contact state with the roller is an angular contact, and the rolling direction of the roller is kept in a straight line with respect to the track groove. It is intended to reduce rolling resistance and reduce rotational third order induced thrust.
Japanese National Patent Publication No. 4-503554 JP-A-5-215141 JP 2000-74086 A

  Since the above conventional technique is a double roller, the number of parts is large, which causes an increase in cost. In order to solve this, as shown in FIG. 18, a type in which a single roller rolls in parallel to the track groove has been proposed (Patent Document 3). However, since this type has a structure in which the needle roller and the tripod spherical journal are in point contact, there is a concern that the contact surface pressure is high and the service life is short.

  Therefore, an object of the present invention is to eliminate the problems of the conventional tripod type constant velocity universal joint as described above. In other words, a tripod type constant velocity universal joint is provided which is a single roller type with a simple structure, in which the roller rolls parallel to the track groove and the contact surface pressure is reduced.

  The tripod type constant velocity universal joint according to the present invention includes an outer joint member formed with a track groove extending in the axial direction at the circumferentially equally divided position of the inner periphery, and a trunnion journal protruding radially from the circumferentially equally divided position. An inner joint member having a roller and a roller rotatably supported by each trunnion journal and housed in the track groove, and a position where the bus bar on the outer peripheral surface of the trunnion journal is offset from the center line of the trunnion journal to the far side The inner surface of the roller is a convex arc surface with the same radius of curvature as the trunnion journal bus, and the same curvature is provided between the outer surface of the trunnion journal and the inner surface of the roller. The drum-shaped rollers are arranged, and at the end of the inner peripheral surface of the roller and the end of the roller, at least on the joint axis side, contact surfaces that contact each other are arranged. It is characterized in that the digits.

  According to a second aspect of the present invention, in the tripod type constant velocity universal joint according to the first aspect, the rollers are aligned with a circumferential clearance on the inner peripheral surface of the roller, and the roller is provided on the inner peripheral surface of the roller with a clearance joint shaft. The roller inscribed circle diameter on the joint axis side is smaller than the maximum diameter of the outer peripheral surface of the trunnion journal in the state of moving to the center side.

  The invention according to claim 3 is the tripod type constant velocity universal joint according to claim 1 or 2, wherein the projection perpendicular to the axis of the trunnion journal is non-circular, and the diameter φD in the direction orthogonal to the axis of the joint is the largest. The diameter φC in the direction parallel to the axis of the joint is minimum, and the relationship of φC <φd <φD is established when the roller inscribed circle diameter at the time of assembly is φd.

  The invention according to claim 4 is the tripod type constant velocity universal joint according to claim 3, wherein the lower limit of the angle range of the maximum diameter φD is 90 °.

  According to the present invention, a single roller type with a simple structure, a roller rolls parallel to the track groove, and a contact surface pressure is reduced, and a tripod type that satisfies all of low cost, low vibration, and long life, etc. A quick universal joint can be provided.

Embodiments of the present invention will be described below with reference to the drawings.
First, a basic configuration of a tripod type constant velocity universal joint will be described with reference to FIGS. 1 and 2. The illustrated tripod type constant velocity universal joint includes an outer ring 10 as an outer joint member, a trunnion 20 as an inner joint member, and a roller assembly 30 as a torque transmission element. The rotation axis of the outer ring 10 and the rotation axis of the trunnion 20 Torque can be transmitted at a constant angular velocity even in a state where is an angle (operating angle). In addition, relative axial displacement between the outer ring 10 and the trunnion 20 is possible.

  The outer ring 10 includes a mouse portion 12 and a stem portion 18, and is connected to one of the two shafts to be coupled by a serration (or spline, hereinafter the same) shaft of the stem portion 18 so that torque can be transmitted. It has become. Three track grooves 14 extending in the axial direction are formed on the inner peripheral surface of the mouse portion 12 at equal intervals in the circumferential direction of the inner peripheral surface. Side walls facing each other in the circumferential direction of each track groove 14 serve as a roller guide surface 16.

  The trunnion 20 is composed of a boss portion 22 and a trunnion journal 26, and is connected to the other of the two shafts to be coupled by a serration hole 24 of the boss portion 22 so as to transmit torque. The trunnion journal 26 protrudes in the radial direction from the circumferentially divided position of the boss portion 22. The outer peripheral surface 28 of the trunnion journal 26 is spherical. Each trunnion journal 26 carries a roller assembly 30.

  The roller assembly 30 includes rollers 32 and 40, and the roller 32 is accommodated in the track groove 14 of the outer ring 10. The outer peripheral surface 34 of the roller 32 is a convex curved surface that fits the roller guide surface 16. A plurality of rollers 40 are interposed between the outer peripheral surface 28 of the trunnion journal 26 and the roller 32, and the roller 32 is rotatable with respect to the trunnion journal 26. That is, the outer peripheral surface 28 of the trunnion journal 26 is an inner raceway surface and the inner peripheral surface of the roller 32 is an outer raceway surface, and the rollers 40 are interposed between these raceway surfaces in a freely rollable manner.

Next, the first embodiment will be described with reference to FIGS.
Although it has been described above that the outer peripheral surface 28 of the trunnion journal 26 has a spherical shape, this includes not only a true spherical surface but also a strictly spherical surface that can be called a pseudo spherical surface. In this embodiment, the generatrix of radius R (FIG. 1) having the center of curvature at the position offset from the generatrix of the outer peripheral surface 28 in the direction away from the axis.

  The roller 32 is accommodated in the track groove 14 of the outer ring 10 and is movable along the track groove 14 in the axial direction of the outer ring 10. At this time, the outer peripheral surface 34 of the roller 32 is guided by the roller guide surface 16 of the outer ring 10 and rolls in parallel with the track groove 14. Accordingly, the frictional resistance is reduced, the induced thrust is reduced, and the shudder phenomenon of the vehicle equipped with the tripod type constant velocity universal joint is reduced.

  The inner peripheral surface 36 of the roller 32 forms a part of an annulus having a convex arc having the same radius of curvature as that of the bus bar of the outer peripheral surface 28 of the trunnion journal 26 as a bus bar. Between the outer peripheral surface 28 of the trunnion journal 26 and the inner peripheral surface 36 of the roller 32, hourglass rollers 40 having the same curvature are arranged on the circumference. In this case, the roller 40 and the outer peripheral surface 28 of the trunnion journal 26 and the roller 40 and the inner peripheral surface 36 of the roller 32 are in line contact with each other, and a low surface pressure can be secured.

  When the tripod type constant velocity universal joint takes an operating angle, as shown in FIG. 3, the centers of the rollers 40 and the trunnion 20 move to the joint axis side, and the rollers 40 along the inner peripheral surface 38 of the roller 32 are moved. The inscribed circle diameter increases. Therefore, a gap (radial) is generated between the inscribed circle diameter of the roller 40 and the outer peripheral surface 28 of the trunnion journal 26. However, the outer peripheral surface 28 of the trunnion journal 26 has a drum shape, in other words, the radius of curvature of the bus bar is made larger than that of a perfect circle, and the bus bar of the corresponding inner peripheral surface 36 of the roller 32 is set in the same manner. Since the increase amount of the inscribed circle diameter when the roller 40 moves along the inner peripheral surface 36 of 32 is reduced, it is possible to suppress the joint rotation direction when the large operating angle is taken.

  In this way, a slide with a simple and low-cost structure that achieves both low induced thrust performance in which the roller 32 rolls parallel to the track groove 14 of the outer ring 10, that is, reduction of vehicle shudder phenomenon and reduction of rotational direction. A constant velocity universal joint can be provided.

  Further, the roller 40 is aligned with the inner circumferential surface 36 of the roller 32 with a circumferential clearance, and is moved downward on the inner circumferential surface of the roller 32 by the clearance (see FIG. 3). In this state, the upper end surface of the roller 40 is clogged and the circumferential clearance becomes zero, and the roller 40 cannot move further downward while being in contact with the inner peripheral surface 36 of the roller 32. In this state, the inscribed circle diameter φB (FIG. 4) of the end portion on the joint axis side of the roller 40 is set to be slightly smaller than the outer diameter φA (FIG. 5) of the trunnion journal 26. When the roller assembly is assembled to 26, the fitting mode is press-fitted, and after fitting, there is a gap between the parts, and good operability can be secured, and it cannot be easily removed.

  Next, the manufacturing method of the roller 40 which is a rolling element is described. In conventional tripod type constant velocity universal joints, needle rollers are used, and the needle rollers are finished by grinding to ensure the shape and accuracy. On the other hand, in the case of the above-described hourglass-shaped roller 40, the grinding process can be abolished and the cost can be reduced. That is, in the case of the tripod type constant velocity universal joint according to the embodiment, since there is an automatic alignment function of the rollers 40 on the circumference due to its structure, it is not necessary to obtain accuracy by grinding, and grinding can be abolished. The roller automatic alignment function is caused by the inner circumferential surface 36 of the roller 32 having a convex arc cross-sectional shape and the rolling surface 42 of the roller 40 having a concave arc cross-sectional shape.

  Referring to FIG. 6, when the roller 40 is disposed on the inner peripheral surface 36 of the roller 32 and a load is applied to the roller 40, the roller 40 is always perpendicular to the rotation direction of the roller 40. The power to keep on works. In a full-roller type bearing using a normal needle roller, if there is a clearance in the circumferential direction or the axial direction, skew (roller inclination) occurs, and accurate rotational motion is hindered. However, the combination of the rollers 32 and 40 has a structure in which skew is hardly generated due to the automatic alignment function of the rollers 40 even if there is a clearance, so that a slight clearance is acceptable, and needle rollers are used. Higher finishing accuracy of the roller 40 than the conventional type is not required.

  An example of a method for processing the roller 40 is turning. As shown in FIG. 7A, a cylindrical material is formed into a drum shape by turning, and heat treatment is performed to obtain an optimum material structure and hardness as a rolling element. Here, since the dimensions of the rollers 40 are slightly changed by the heat treatment, all the rollers 40 are selected after the heat treatment, and the rollers 32, the rollers 40, and the trunnion journal 26 are combined with an optimum clearance.

  Furthermore, when it is necessary to improve the surface roughness of the roller surface, barrel processing can be performed after the heat treatment to improve the surface roughness.

  Another example of the method of processing the roller 40 is rolling. As shown in FIG. 7B, a cylindrical material is formed into a drum shape by rolling. Turning (cutting) processing is a processing method that obtains the desired dimensions and shape by removing unnecessary parts of the material as chips. In rolling, processing is performed with almost no volume change from the material to the finished shape. Can do. That is, as is clear from comparison between FIGS. 7A and 7B, since the material can be used almost 100% in the case of rolling, it is economical and leads to cost reduction.

  After rolling, heat treatment is performed to obtain an optimum material structure and hardness as a rolling element. Further, since the dimensions of the rollers 40 are slightly changed by the heat treatment, all the rollers 40 are selected after the heat treatment, and the rollers 32, the rollers 40, and the trunnion journal 26 are combined with an optimum clearance.

  Next, the embodiment shown in FIGS. 8, 9, and 10 is provided with abutting surfaces 38 and 44 (FIGS. 10B and 10C) that engage with each other at the end portion 40 of the inner peripheral surface of the roller 32. Thus, the trunnion 20 and the roller assembly (32, 40) are prevented from being disassembled. As shown in FIG. 10A, when the trunnion journal 26 is displaced in the axial direction of the trunnion 20 with respect to the roller 32, the roller 40 is displaced along the inner peripheral surface 36 of the roller 32. Since the contact surface 38 is provided at the lower end portion of the circumferential surface 36, the contact surface 44 of the roller 40 contacts the contact surface 38, and further displacement of the roller 40 is prevented.

  The angle C of the contact surface 44 of the roller 40 and the angle D of the contact surface 38 of the roller 32 may be 10 ° or more and 90 ° or less. However, in order to prevent decomposition more firmly, the angles C and D are preferably small and are preferably set to 10 ° or more and 40 ° or less. If the contact surfaces 38 and 44 are provided at least at the end of the roller 40 and the roller 32 on the trunnion 20 axis side, the above-described action can be obtained. However, as in the illustrated embodiment, the contact surfaces 38 and 44 are provided at both ends of the roller 32. By adopting a symmetrical shape, the number of parts management man-hours can be reduced.

  As shown in FIG. 11, the inscribed circle diameter φB on the joint axis side of the roller 40 when the roller 40 is arranged on the inner peripheral surface 36 of the roller 32 and aligned at a position where the contact surfaces 38 and 44 come into contact with each other is as follows. The outer diameter (maximum diameter) φA of the trunnion journal 26 is set to be slightly smaller. By doing so, when the roller assemblies 32 and 40 are assembled to the trunnion journal 26, the fitting mode is press-fitted, and after fitting, there is a gap between the parts, so that good operability can be secured, and easily I can't come off.

  In the embodiment shown in FIG. 12, the projection shape viewed from the shaft end side of the trunnion journal 26, in other words, the projection shape perpendicular to the axis is a non-circular shape. Then, the inscribed circle diameter on the joint axis side of the roller 40 when the roller 40 is arranged on the inner peripheral surface 36 of the roller 32 and aligned at a position where the contact surfaces 38 and 44 contact each other is φd (FIG. 12A )), When the diameter of the load receiving side (direction perpendicular to the joint axis) is φD, and the diameter of the side receiving the load and 90 ° direction (parallel to the joint axis) is φC (FIG. 12B) By setting C <d <D, when the roller assembly 30 is press-fitted into the trunnion journal 26, the roller 32 is elastically deformed to reduce the diameter in the C direction and expand the diameter in the D direction. Therefore, the fitting is possible even if the tightening margin is large to some extent. In addition, the projected shape viewed from the shaft end side of the trunnion journal 26 is a perfect circle (a part of) in the range on the side receiving the load indicated by the symbol θ, and the diameter is gradually reduced in the other ranges to minimize the minimum diameter φC. It may be connected. By setting the range θ to 90 ° or more, the durability of the trunnion 20 is improved.

  In the embodiment shown in FIG. 13, the rolling resistance of the roller 32 is further reduced by changing the cross-sectional shape of the roller guide surface 16 of the outer ring 10 to further improve the low vibration performance and durability. Specifically, the cross-sectional shape of the roller guide surface 16 forms a part of an annulus having an arc whose radius of curvature R is smaller than the radius of the outer peripheral surface 34 of the roller 32 as a generating line. By adopting such a configuration, when the joint rotates with the operating angle taken, the roller 32 rolls and reciprocates on the roller guide surface 16 of the outer ring 10. At this time, the roller 32 includes the axis of the outer ring 10. The inclination of the roller 32 in the plane (see FIG. 14) is automatically corrected by the generation of a couple when torque is applied.

  FIG. 15 shows an embodiment in which the inclination of the roller (see FIG. 15B) in a plane perpendicular to the axis of the outer ring 10 is suppressed. As shown in FIG. 15A, a tapered surface 33 is formed from the outer peripheral surface 34 to the side surface in the immediate vicinity of the torque load surface of the roller 32, and on the other hand, the end portion on the joint axis side of the track groove 14 is formed. A guide 15 is provided. When the roller 32 tilts as shown in FIG. 15B, the guide 15 receives the tapered surface 33 and prevents the roller 32 from tilting further. As for the position where the guide 15 is provided, when the roller 32 is inclined, the tapered surface 33 and the guide 15 are first brought into contact with each other to limit the inclination of the roller 32, and the opposite side of the roller 32 (the left side in FIG. 15B). It is desirable to set so that does not come into contact with the flange portion 17 of the outer ring 10.

It is a cross-sectional view of a tripod type constant velocity universal joint showing an embodiment. It is a longitudinal cross-sectional view of the tripod type constant velocity universal joint of FIG. It is a longitudinal cross-sectional view of the tripod kit which removed the outer ring | wheel from the coupling of FIG. (A) is sectional drawing of a roller assembly, (B) is a top view of a roller assembly, (C) is a bottom view of a roller assembly. It is a top view of a trunnion. (A) is sectional drawing of a roller assembly, (B) is a figure for demonstrating the automatic alignment function of a roller. (A) is a front view for demonstrating the processing method of the roller by turning, (B) is a front view for demonstrating the processing method of the roller by rolling. It is a cross-sectional view of a tripod type constant velocity universal joint showing another embodiment. It is a longitudinal cross-sectional view of the tripod type constant velocity universal joint of FIG. (A) is the elements on larger scale of FIG. 8, (B) is an expanded sectional view of a roller, (C) is an expanded sectional view of a roller. It is a figure which shows the process in which a roller assembly is assembled | attached to a trunnion journal. (A) is a top view of a roller assembly, (B) is a top view of a trunnion. It is a partial cross section figure of the tripod type constant velocity universal joint which shows another Example. It is a fragmentary perspective view of the roller of the inclined state. FIG. 14 is a partial cross-sectional view similar to FIG. 13, where (A) shows a normal state of the roller assembly and (B) shows a state where the roller assembly is tilted. It is a partial cross-sectional view of a tripod type constant velocity universal joint showing the prior art. It is a partial cross-sectional view of a tripod type constant velocity universal joint showing the prior art. It is a cross-sectional view of a tripod type constant velocity universal joint showing the prior art.

Explanation of symbols

10 Outer ring (outer joint member)
12 mouse part 14 track groove 15 guide 16 roller guide surface 17 collar 18 stem part 20 trunnion (inner joint member)
22 Boss portion 24 Serration hole 26 Trunnion journal 28 Outer peripheral surface 30 Roller assembly 32 Roller 33 Tapered portion 34 Outer peripheral surface 36 Inner peripheral surface 38 Abutment surface 40 Roller 42 Rolling surface 44 Abutment surface

Claims (4)

An outer joint member having a track groove extending in the axial direction at the circumferentially equally divided position of the inner periphery, an inner joint member having a trunnion journal protruding radially from the circumferentially equally divided position, and rotating to each trunnion journal A roller freely supported and housed in the track groove,
The bus on the outer peripheral surface of the trunnion journal is an arc with a center of curvature at a position offset from the center line of the trunnion journal to the far side. A drum-shaped roller having the same curvature as that between the outer peripheral surface of the trunnion journal and the inner peripheral surface of the roller, and at least of the end of the inner peripheral surface of the roller and the end of the roller Tripod type constant velocity universal joint provided with contact surfaces that contact each other on the joint axis side.   With the rollers aligned on the inner circumferential surface of the roller with a clearance in the circumferential direction, the roller inscribed circle diameter on the joint axis side is the same as the roller has moved to the joint axis side by the clearance on the inner circumferential surface of the roller. The tripod type constant velocity universal joint of Claim 1 smaller than the maximum diameter of the outer peripheral surface of a trunnion journal.   The projection perpendicular to the axis of the trunnion journal is non-circular, the diameter φD in the direction orthogonal to the joint axis is the largest, the diameter φC in the direction parallel to the joint axis is the smallest, and the roller during assembly The tripod type constant velocity universal joint according to any one of claims 1 to 3, wherein a relationship of φC <φd <φD is established when an inscribed circle diameter is φd.   The tripod type constant velocity universal joint according to claim 4, wherein the lower limit of the angle range of the maximum diameter φD is 90 °.

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