JP2009008233A - Tripod type constant velocity universal joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tripod type constant velocity universal joint which is a simple structure single roller type, in which rollers roll in parallel with a track groove and contact pressure is reduced. <P>SOLUTION: In the tripod type constant velocity universal joint, a generating line of an outer circumference surface 28 of a trunnion journal 26 is set on an arc having a curvature center at a position offset from a center line of the trunnion journal 26 to a far side, an inner circumference surface shape of the roller 32 is formed in a convex arc surface having same curvature radius as the generating line of the trunnion journal 26, and hourglass shape rollers 40 having same curvature as them are arranged between an outer circumference surface 28 of the trunnion journal 26 and an inner circumference surface of the roller 32. The rollers 40 are formed by component rolling and are combined with the roller 32 and the trunnion journal 26 after dimension sorting of all of them after heat treatment. <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 roller rolling direction 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, this type has a structure in which the needle roller and the tripod spherical journal are in point contact with each other, so that the contact surface pressure is high, and there is a concern about the short life.

  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 in parallel with 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 farther from the center line of the trunnion journal 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 rollers are formed by rolling and forming the shape by rolling, and after the heat treatment, all the dimensions are selected. Characterized in that it is a combination with microcrystalline the trunnion journal.

  According to a second aspect of the present invention, in the tripod type constant velocity universal joint of the first aspect, the roller is subjected to barrel processing after heat treatment to improve surface roughness.

  A contact surface that can contact each other may be provided on at least an end portion of the inner peripheral surface of the roller on the axial center side of the inner joint member and an end portion of the roller on the corresponding side. . By doing so, it is possible to prevent the inner joint member and the roller assembly from being disassembled. That is, when the trunnion journal is displaced in the axial direction of the inner joint member with respect to the roller, the roller is displaced along the inner peripheral surface of the roller, but the lower end portion of the inner peripheral surface of the roller has a contact surface, The contact surface of the roller contacts this contact surface, and further displacement of the roller is prevented.

  If the preferable example of the angle of a contact surface is given, it will be 10 degrees or more and 40 degrees or less, More preferably, they are 10 degrees or more and 40 degrees or less (Claim 4). The angle of the contact surface may be 10 ° or more and 90 ° or less, but in order to prevent decomposition more firmly, the angle of the contact surface is preferably smaller and is set to 10 ° or more and 40 ° or less. Is preferred.

  As an example of the shape of the trunnion journal, the projection perpendicular to the axis is non-circular, the diameter φD in the direction orthogonal to the axis of the inner joint member is the largest, and the diameter φC in the direction parallel to the axis of the inner joint member is the smallest The relationship of φC <φd <φD may be established when the inscribed circle diameter of the roller at the time of assembly is φd (Claim 5). By adopting such a configuration, when the roller assembly is press-fitted into the trunnion journal, the roller is elastically deformed to reduce the diameter in the minimum diameter C direction and expand the diameter in the maximum diameter D direction. Even if it is large, it can be fitted.

  By setting the lower limit of the angle range of the maximum diameter φD to 90 ° (Claim 6), the durability of the inner joint member is improved.

  The outer peripheral surface of the roller is, for example, a part of an annulus having an arc whose radius of curvature is smaller than 1/2 of the roller diameter as a generating line. By adopting such a configuration, when the joint rotates with the operating angle taken, the roller rolls and reciprocates on the roller guide surface of the outer joint member. At this time, the axis includes the axis of the outer joint member. The inclination of the roller in the plane is automatically corrected by generating a couple when torque is applied.

  A tapered surface is formed from the outer peripheral surface to the end surface of the roller, and a guide is provided at the end of the track groove on the outer joint member axial center side. When the roller is inclined in a plane perpendicular to the axis of the outer joint member, the guide By receiving the tapered surface (Claim 8), the inclination of the roller in a plane perpendicular to the axis of the outer joint member can be suppressed.

  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 includes a boss portion 22 and a trunnion journal 26. The trunnion 20 is connected to the other of the two shafts to be coupled by a serration hole 24 of the boss portion 22 so that torque can be transmitted. 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 with the same radius of curvature as that of the generatrix of the outer peripheral surface 28 of the trunnion journal 26 as a generatrix. 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 axial center 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 amount of increase in 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, the tripod type constant velocity universal joint of the embodiment has an automatic alignment function of the rollers 40 on the circumference because of its structure, so that it is not necessary to obtain accuracy by grinding processing 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 the processing method of the roller 40 is rolling. As shown in FIG. 7A, a cylindrical material is formed into a drum shape by turning. 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. As is clear from comparison with FIG. 7B showing the case of turning as a comparative example, in the case of rolling, the material can be used almost 100%, which 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 journals 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.

  Next, the embodiment shown in FIGS. 8, 9, and 10 is provided with contact surfaces 38 and 44 (FIGS. 10B and 10C) that can contact 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 peripheral 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 contact surface 44 of the roller 40 is a taper having a smaller diameter toward the end of the roller 40, and an angle α formed by the contact surface 44 with respect to a plane perpendicular to the axis of the roller 40 is the angle of the contact surface 44. I will call it. The contact surface 38 of the roller 32 is a taper having a smaller diameter toward the end surface of the roller 32, and an angle β formed by the contact surface 38 with respect to a plane perpendicular to the axis of the roller 32 is called an angle of the contact surface 38. I will do it. Both the angle α of the contact surface 44 of the roller 40 and the angle β 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, these angles α and β 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 projected shape viewed from the shaft end side of the trunnion journal 26, in other words, the projected shape perpendicular to the axis of the trunnion journal 26 is a non-circular shape. The axis of the trunnion 20 is indicated by a one-dot chain line in FIG. Then, the inscribed circle diameter on the trunnion shaft center 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 )), The diameter on the side that receives the load during torque transmission (direction perpendicular to the trunnion axis) is φD (FIG. 12B), and the side that receives the load is 90 ° (the direction parallel to the trunnion axis) When the diameter of the roller assembly 30 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. In addition, since the diameter is increased in the D direction, the fitting is possible even if the interference is large to some extent. Further, the projection 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 subjected to 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 angle range θ of the maximum diameter φD 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 ½ of the diameter of the roller 32 as a generating line. In this case, the outer peripheral surface 34 of the roller 32 is also a part of an annulus having a radius of curvature smaller than a half of the roller diameter 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 end surface in the immediate vicinity of the torque load surface of the roller 32, and on the other hand, the end portion of the track groove 14 on the outer ring axial center side is opposed thereto. 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 rolling, (B) is a front view for demonstrating the processing method of the roller by turning. 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 Contact surface 40 Roller 42 Rolling surface 44 Contact surface

Claims (8)

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 having a center of curvature at a position offset from the center line of the trunnion journal to the far side, and the inner peripheral surface shape of the roller is a convex arc surface having the same radius of curvature as the bus of the trunnion journal. And drum-shaped rollers having the same curvature as those between the outer peripheral surface of the trunnion journal and the inner peripheral surface of the roller,
A tripod type constant velocity universal joint, wherein the roller is formed by rolling and is combined with the roller and the trunnion journal after all the dimensions are selected after heat treatment.   The tripod constant velocity universal joint according to claim 1, wherein the roller is subjected to barrel processing after heat treatment to improve surface roughness.   The tripod of Claim 1 or 2 which provided the contact surface which can contact | abut at least the edge part of the axial center side of the said inner joint member of the inner peripheral surface of the said roller, and the edge part of the said roller of a corresponding side. Type constant velocity universal joint.   The tripod type constant velocity universal joint according to claim 3, wherein an angle of the contact surface is 10 ° or more and 40 ° or less.   The projection of the trunnion journal perpendicular to the axis is non-circular, the diameter φD in the direction orthogonal to the axis of the inner joint member is the largest, and the diameter φC in the direction parallel to the axis of the inner joint member is the smallest The tripod type constant velocity universal joint according to any one of claims 1 to 5, wherein a relation of φC <φd <φD is established when the inscribed circle diameter of the roller at the time of assembly is φd.   The tripod type constant velocity universal joint according to claim 5, wherein the lower limit of the angle range of the diameter φD is 90 °.   The tripod type constant velocity universal joint according to any one of claims 1 to 6, wherein the outer peripheral surface of the roller is a part of an annulus having a radius of curvature smaller than a half of the roller diameter as a generating line.   A tapered surface is formed from the outer peripheral surface to the end surface of the roller, a guide is provided at an end of the track groove on the outer joint member axial center side, and the roller is inclined in a plane perpendicular to the axis of the outer joint member. The tripod type constant velocity universal joint according to any one of claims 1 to 7, wherein the guide is configured to receive the tapered surface.

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