JP2006097853A - Constant velocity universal joint and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a constant velocity universal joint having improved assembling work efficiency by easily assembling a retaining ring on a roller. <P>SOLUTION: The constant velocity universal joint comprises an outside joint member having three axial track grooves formed at the inner periphery and axial roller guide faces on both sides of each of the track grooves, a tripod member having three leg shafts protruded in the radial direction, and a roller assembly mounted to each of the leg shafts of a tripod member and having a ring roller 34 guided along the roller guide face so as to be swingable relative to the leg shaft. An annular recessed groove 33 is formed on the inner peripheral face of the roller 34 and the retaining ring is fitted into the recessed groove 33 for restricting the axial movement of the other assembled component. The edge 38 of the recessed groove 33 has a sectionally R-curved shape with a tangent line between the inner peripheral face 34b of the roller 34 and the inner wall face 33a of the recessed groove 33. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sliding tripod type constant velocity universal joint and a method for manufacturing the same. In general, a constant velocity universal joint is a type of universal joint that connects two shafts on the drive side and the driven side and can transmit rotational force at a constant speed even if there is an angle between the two shafts. In the formula type, relative axial displacement between the two axes is made possible by plunging the joint, and the tripod type has a tripod member having three leg shafts projecting in the radial direction on one axis. A hollow cylindrical outer joint member having three track grooves extending in the axial direction is coupled to the other shaft, and the leg shaft of the tripod member is accommodated in the track groove of the outer joint member to transmit torque. It is intended to do.

  For example, a tripod type constant velocity universal joint is one type of constant velocity universal joint used as a means for transmitting rotational force from an automobile engine to wheels at a constant speed. This tripod type constant velocity universal joint connects two shafts on the drive side and the driven side, transmits rotational torque at a constant speed even if the two shafts take an operating angle, and also allows relative displacement in the axial direction. It has a structure that can

  In general, the tripod type constant velocity universal joint has an outer joint member in which three track grooves in the axial direction are formed on the inner periphery, and each has an axial roller guide surface on each side of each track groove, and a radius A tripod member having three leg shafts protruding in the direction and a roller rotatably accommodated between the leg shaft of the tripod member and the roller guide surface of the outer joint member are configured as main members. One of the two shafts is connected to the outer joint member, and the other is connected to the tripod member.

  In this way, the leg shaft of the tripod member and the roller guide surface of the outer joint member engage with each other in the rotational direction of the two shafts via the roller, so that the rotational torque is transmitted from the drive side to the driven side at a constant speed. Further, each roller rolls on the roller guide surface while rotating with respect to the leg shaft, so that the relative axial displacement and angular displacement between the outer joint member and the tripod member are absorbed.

  This tripod type constant velocity universal joint has a structure in which a roller is mounted on the outer peripheral surface of a leg shaft via a plurality of needle rollers, and the rotational torque is obtained while the outer joint member and the tripod member take an operating angle. As the leg shaft tilts, the rollers and the roller guide surfaces become obliquely crossed with each other, causing slippage between the two, preventing smooth rolling of each roller and preventing induced thrust. There is a problem that becomes larger. Further, there is a problem that the sliding resistance when the outer joint member and the tripod member are relatively displaced in the axial direction is increased by the frictional force between each roller and the roller guide surface.

  The induced thrust is the thrust force generated by the friction inside the joint when the constant velocity universal joint is rotated at a certain angle, and in the case of the tripod type, it is mainly strong as a tertiary component. Appear. The sliding resistance is a sliding joint such as a tripod type constant velocity universal joint, and refers to the magnitude of the axial friction force generated when the outer joint member and the tripod member slide relative to each other.

  Tripod type equipped with a roller assembly that allows the roller to tilt and displace in the axial direction to eliminate induced thrust and sliding resistance by eliminating the problem of the roller and roller guide surface being obliquely crossed. Various constant velocity universal joints have been proposed.

  As a tripod type constant velocity universal joint of this kind, a roller assembly is configured by rotatably assembling a roller to a ring via a plurality of needle rollers, and an inner peripheral surface of the ring is formed in an arc-shaped convex cross section to form a leg shaft. There is known a configuration in which the outer peripheral surface is externally fitted (for example, see Patent Document 1). The needle roller is disposed between the cylindrical outer peripheral surface of the ring and the cylindrical inner peripheral surface of the roller in a so-called full roller state, and is prevented from coming off by an annular retaining ring.

  According to this configuration, the roller assembly can be tilted and displaced in the axial direction with respect to the leg shaft by sliding between the convex curved inner peripheral surface of the ring and the convex curved outer peripheral surface of the leg shaft. It can be avoided that the roller and the roller guide surface are in an oblique state.

  In addition, the cross-sectional shape of the leg shaft is in contact with the inner peripheral surface of the ring in a direction orthogonal to the axis of the joint, and a gap is formed between the inner peripheral surface of the ring in the axial direction of the joint, For example, it is oval.

Accordingly, when the joint takes an operating angle, the leg shaft can be inclined with respect to the outer joint member without changing the posture of the roller assembly. In addition, since the contact ellipse between the outer peripheral surface of the leg shaft and the ring approaches the point from the horizontally long, the friction moment for tilting the roller assembly is reduced. Accordingly, the posture of the roller assembly is always stable, and the roller is held parallel to the roller guide surface, so that it can roll smoothly.
JP 2000-320563 A

  In the tripod type constant velocity universal joint described above, in order to reduce induced thrust and slide resistance that cause vibration and noise of the car body, a roller assembly is used and the cross section of the leg shaft is made elliptical. Thus, the roller assembly can swing freely even when the operating angle is taken, and the roller assembly can be smoothly rolled while maintaining a constant posture on the track groove of the outer joint member. Therefore, it is possible to achieve low vibration that can maintain the induced thrust and the slide resistance constantly and stably without depending on the operating angle.

  By the way, as described above, the roller assembly includes a configuration in which the roller is rotatably assembled to the ring via a plurality of needle rollers, and the needle rollers in the full-roller state are retained by an annular retaining ring. As shown in FIGS. 9 and 10, the roller 1 in the roller assembly has an inner peripheral surface constituting a roller raceway surface 1 a, and an annular groove 2 for fitting a retaining ring on the inner peripheral surface. Is formed.

  In the manufacture of this constant velocity universal joint, the entire inner peripheral surface of the roller 1, that is, the roller raceway surface 1 a positioned inside the concave groove 2 and the flange surface 1 b positioned outside the concave groove 2 are polished. Turning is performed with a special processing jig 3 with a margin (see FIG. 11), and after the heat treatment, both the roller raceway surface 1a and the flange surface 1b are polished simultaneously.

  Since the entire inner peripheral surface of the roller 1 is polished after the turning of the concave groove 2 in this way, the edge portion 4 of the concave groove 2, that is, the inner wall surface 2 a of the concave groove 2 and the flange surface after the polishing processing. Since the connecting portion with 1b has a discontinuous R-shape, when the retaining ring 5 is inserted into the recessed groove 2 of the roller 1 as shown in FIG. It may be easily caught and it may be difficult to smoothly insert the retaining ring 5 into the concave groove 2.

  Therefore, the present invention has been proposed in view of the above-described problems, and the object of the present invention is to make it possible to easily assemble the retaining ring to the roller and to improve the assembly workability. It is in providing a coupling and its manufacturing method.

  As a technical means for achieving the above-described object, the constant velocity universal joint according to the present invention has three track grooves in the axial direction formed in the inner peripheral portion, and an axial roller on each side of each track groove. An outer joint member having a guide surface, a tripod member having three leg shafts projecting in the radial direction, and a roller attached to each leg shaft of the tripod member and swinging freely with respect to the leg shaft. A roller assembly having a ring-shaped roller guided along the guide surface, and forming an annular groove on the inner peripheral surface of the roller, and restricting axial movement of other assembly parts in the groove. In the constant velocity universal joint fitted with a retaining ring, the edge portion of the groove has an R-curved cross-sectional shape in which the inner peripheral surface of the roller and the inner wall surface of the groove are tangent.

  Further, the constant velocity universal joint manufacturing method according to the present invention includes an outer joint member in which three track grooves in the axial direction are formed on the inner peripheral portion, and an axial roller guide surface is provided on each side of each track groove. A tripod member having three leg shafts projecting in the radial direction, and a tripod member mounted on each leg shaft of the tripod member, and swingable with respect to the leg shaft and guided along the roller guide surface. A roller assembly having a ring-shaped roller, and an annular concave groove is formed on the inner peripheral surface of the roller, and a constant ring is fitted in the concave groove to restrict axial movement of other assembly parts. A method for manufacturing a universal joint, wherein the edge portion of the groove is formed by simultaneous turning of the inner peripheral surface of the roller and the concave groove so that the cross-sectional shape of the inner peripheral surface of the roller and the inner wall surface of the concave groove is tangent. To form an R curved surface And butterflies.

  In the present invention, the edge portion of the concave groove to which the retaining ring is fitted is an R curved surface with the inner peripheral surface of the roller and the inner wall surface of the concave groove as a tangent line, so that the inner peripheral surface of the roller and the concave groove are Since the edge part which is a connecting part with the inner wall surface has a continuous R shape, when the retaining ring is inserted into the concave groove on the inner peripheral surface of the roller, the retaining ring is not caught by the edge part of the concave groove. Can be smoothly inserted into the groove. The edge portion of the concave groove can be easily formed by simultaneous turning of the inner peripheral surface of the roller and the concave groove.

  In the above-described configuration, it is desirable that the inner circumferential surface of the roller positioned on the outer side of the concave groove is formed to have a larger diameter than the inner peripheral surface of the roller positioned on the inner side of the concave groove. In this way, when inserting the retaining ring into the concave groove, the deformation of the retaining ring can be reduced as much as possible, so that the insertion operation is facilitated. This processing can be easily realized by simultaneous turning of the inner peripheral surface of the roller and the groove.

  Also, if the roller inner peripheral surface located outside the concave groove is formed to have a larger diameter than the roller inner peripheral surface located inside the concave groove, the roller located inside the concave groove When the inner peripheral surface becomes a roller raceway surface, it is only necessary to polish only the inner peripheral surface of the roller. As a result, the processing time can be shortened and the cost can be reduced.

  In the present invention, the leg shaft of the tripod member has a substantially elliptical shape in which the cross section of the leg shaft is perpendicular to the axis of the joint, and the roller assembly has a plurality of rollers mounted on a ring that is externally fitted to the outer peripheral surface of the leg shaft. If it is applied to a tripod type constant velocity universal joint having a structure in which a roller is rotatably supported via a moving body, it is desirable in that the desired effect is exhibited. Here, the “substantially elliptical shape” includes not only the literally elliptical shape but also a shape generally called an oval shape or an oval shape. Further, needle rollers can be used as the rolling elements.

  According to the present invention, the edge portion of the concave groove to which the retaining ring is fitted has an R-curved cross-sectional shape with the inner peripheral surface of the roller and the inner wall surface of the concave groove as a tangent line. Since the edge portion that is a connecting portion between the surface and the inner wall surface of the concave groove has a continuous R shape, when the retaining ring is inserted into the concave groove of the roller, the retaining ring is not caught by the edge portion of the concave groove, The retaining ring can be smoothly inserted into the concave groove, and workability is greatly improved.

  Embodiments of the constant velocity universal joint and its manufacturing method according to the present invention will be described in detail below. 1 and 2 show the overall configuration of the constant velocity universal joint, FIG. 3 shows the leg shaft and roller assembly of the constant velocity universal joint, and FIG. 4 shows the overall configuration of the roller assembly.

  The tripod type constant velocity universal joint of this embodiment is composed mainly of an outer joint member 10 and a tripod member 20 as shown in FIGS. 1 and 2, and one of the two shafts to be connected on the driving side and the driven side is It is connected to the outer joint member 10, and the other is connected to the tripod member 20, so that the rotational torque can be transmitted at a constant speed even when the operating angle is taken, and the relative displacement in the axial direction can be allowed.

  The outer joint member 10 has a substantially cylindrical cup shape with one end opened and the other end closed (see FIG. 2), and one shaft (not shown) is integrally provided at the other end, and the inner peripheral portion has Three track grooves 12 extending in the axial direction are formed around the central axis at intervals of 120 °. Each track groove 12 is formed with a concave curved roller guide surface 14 in the axial direction on the side walls facing each other in the circumferential direction.

  The tripod member 20 has three leg shafts 22 protruding in the radial direction, and is held by serration (spline) fitting on the other shaft (not shown). A roller 34 is attached to each leg shaft 22, and this roller 34 is accommodated in the track groove 12 of the outer joint member 10, and the outer peripheral surface of the roller 34 forms a convex curved surface that fits the roller guide surface 14.

  The outer peripheral surface of the roller 34 is a convex curved surface with a circular arc having a center of curvature at a position away from the axis of the leg shaft 22 in the radial direction, and the cross-sectional shape of the roller guide surface 14 is a Gothic arch having two radii of curvature. Thus, the outer peripheral surface of the roller 34 and the roller guide surface 14 are in angular contact. In FIG. 1, action lines of two contact points that are in angular contact are indicated by a one-dot chain line. Even if the cross-sectional shape of the roller guide surface 14 is tapered with respect to the outer circumferential surface of the convex curved surface of the roller 34, the angular contact between them can be realized.

  As described above, the angular contact between the outer peripheral surface of the roller 34 and the roller guide surface 14 makes the roller 34 difficult to shake, so that the posture can be stabilized. When the angular contact is not employed, for example, the roller guide surface 14 is constituted by a part of a cylindrical surface whose axis is parallel to the axis of the outer joint member 10, and the cross-sectional shape thereof is a generatrix of the outer peripheral surface of the roller 34. It can also be a corresponding arc.

  On the other hand, a ring 32 is fitted on the outer peripheral surface of the leg shaft 22. The ring 32 and the roller 34 are unitized via a plurality of rolling elements, for example, needle rollers 36, and constitute a roller assembly 37 capable of relative rotation. That is, the cylindrical outer peripheral surface 32a of the ring 32 is used as the inner roller raceway surface, and the cylindrical inner peripheral surface 34a of the roller 34 is used as the outer roller raceway surface, and the needle rollers 36 roll between these inner and outer roller raceway surfaces. Intervene freely. As shown in FIG. 3, the needle rollers 36 are incorporated in a so-called full roller state without a cage.

  In order to restrict the relative movement of the ring 32, needle roller 36 and roller 34 in the axial direction thereof, as shown in FIG. 4, an annular groove 33 provided on the inner peripheral surface 34a of the roller 34. A retaining ring 35 is fitted to the end. The retaining ring 35 restricts the relative movement of these members in the axial direction with respect to the roller 34 by contacting the end surface of the ring 32 and the end surface of the needle roller 36. It has become. The retaining ring 35 has a ring-like shape with a cut at one place in the circumferential direction, and is fitted in the concave groove 33 of the roller 34 in a state of being elastically reduced in diameter.

  As shown in FIG. 5 and FIG. 6, the roller 34 in this embodiment is formed with a concave groove 33 for fitting the retaining ring 35 on the inner peripheral surface thereof. A portion located inside the concave groove 35 constitutes a roller raceway surface 34a, and a portion located outside the concave groove 33 serves as a flange surface 34b.

  On the inner peripheral surface of the roller 34, the edge portion 38 of the concave groove 33 has an R-curved cross-sectional shape in which the inner wall surface 33 a and the flange surface 34 b of the concave groove 33 are tangent. In order to make the edge portion 38 of the concave groove 33 into an R curved surface, a processing jig 39 having a shape as shown in FIG. 7 is used, and the concave groove 33 and the flange surface 34b are simultaneously formed without any margin for polishing. It can be easily formed by turning.

  As described above, the edge portion 38 of the concave groove 33 to which the retaining ring 35 is fitted has an R-curved cross-sectional shape in which the inner wall surface 33a and the flange surface 34b of the concave groove 33 are tangent. Since the edge portion 38 which is a connecting portion between the inner wall surface 33a and the flange surface 34b has a continuous R shape, the retaining ring 35 is inserted into the recessed groove 33 of the roller 34 as shown in FIG. However, the retaining ring 35 can be smoothly inserted into the concave groove 33 without being caught by the edge portion 38 of the concave groove 33.

When simultaneously turning the concave groove 33 and the flange surface 34b, the edge portion 38 of the concave groove 33 is formed into an R curved surface, and the flange surface 34b is formed to have a larger diameter than the roller raceway surface 34a (FIG. 6). D ₁ > D ₂ ). In this way, when the retaining ring 35 is inserted into the recessed groove 33, the deformation of the retaining ring 35 can be reduced as much as possible, and the insertion operation is facilitated.

  Further, if the flange surface 34b is formed to have a larger diameter than the roller raceway surface 34a as described above, only the roller raceway surface 34a of the entire inner peripheral surface of the roller 34 need only be polished. Processing time can be shortened and costs can be reduced.

  On the other hand, the outer peripheral surface of the leg shaft 22 has a straight shape parallel to the axis of the leg shaft 22 when viewed in a longitudinal section, and has an elliptical shape whose major axis is orthogonal to the axis of the joint when viewed in a transverse section. The cross-sectional shape of the leg shaft 22 is substantially elliptical by reducing the wall thickness seen in the axial direction of the tripod member 20. In other words, the cross-sectional shape of the leg shaft 22 is such that the surfaces of the tripod member 20 facing each other in the axial direction are retracted in the mutual direction, that is, on the smaller diameter side than the virtual cylindrical surface.

  On the other hand, the inner peripheral surface of the ring 32 has an arcuate convex cross section. Since the cross-sectional shape of the leg shaft 22 is substantially elliptical as described above, and a predetermined gap is provided between the leg shaft 22 and the ring 32, the ring 32 is the axis of the leg shaft 22. In addition to being able to move in the direction, it can swing and swing with respect to the leg shaft 22. Further, as described above, since the ring 32 and the roller 34 are unitized so as to be relatively rotatable via the needle rollers 36, the ring 32 and the roller 34 can swing as a unit with respect to the leg shaft 22. There is a relationship. Here, swinging means that the axes of the ring 32 and the roller 34 are inclined with respect to the axis of the leg shaft 22 in a plane including the axis of the leg shaft 22.

  In this constant velocity universal joint, the cross section of the leg shaft 22 is substantially elliptical, and the cross section of the inner peripheral surface of the ring 32 is an arcuate convex cross section. The area is also reduced. Accordingly, the force for tilting the roller assembly 37 is greatly reduced, and the stability of the posture of the roller 34 is further improved. Thereby, the induced thrust and the slide resistance are reduced, and the variation range of these values is also reduced. Therefore, this constant velocity universal joint can set the prescribed values of induced thrust and slide resistance to be small, and can be regulated within the prescribed values with high accuracy.

  The tripod type constant velocity universal joint according to the present invention can be applied to power transmission units of automobiles, aircraft, ships, various industrial machines, and the like.

In embodiment of this invention, it is a cross-sectional view which shows the whole structure of a tripod type constant velocity universal joint. It is sectional drawing which shows the state which took the operating angle in the longitudinal cross-section of the constant velocity universal joint of FIG. It is sectional drawing which shows the leg axis | shaft and roller mechanism of the tripod member of FIG. It is a principal part enlarged view which shows the roller assembly of FIG. It is an expanded sectional view which shows the roller of FIG. It is a principal part expanded sectional view of FIG. It is sectional drawing which shows the processing jig which processes the ditch | groove of FIG. It is sectional drawing which shows the state which inserts a retaining ring in the ditch | groove of FIG. It is sectional drawing which shows the roller in the conventional constant velocity universal joint. It is a principal part expanded sectional view of FIG. It is sectional drawing which shows the processing jig which processes the ditch | groove of FIG. It is sectional drawing which shows the state which inserts a retaining ring in the ditch | groove of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Outer joint member 12 Track groove 14 Roller guide surface 20 Tripod member 22 Leg shaft 32 Ring 33 Concave groove 33a Inner wall surface 34 Roller 34b Inner peripheral surface (back surface)
35 Retaining ring 36 Rolling element (Needle roller)
37 Roller assembly 38 Edge

Claims (6)

  Tripod member having three axial track grooves formed on the inner periphery, outer joint members having axial roller guide surfaces on both sides of each track groove, and three leg shafts projecting in the radial direction And a roller assembly having a ring-shaped roller that is attached to each leg shaft of the tripod member, swings freely swingable with respect to the leg shaft, and is guided along the roller guide surface. In a constant velocity universal joint in which an annular concave groove is formed on the inner peripheral surface and a retaining ring for restricting the axial movement of other assembly parts is fitted in the concave groove, the edge portion of the concave groove is formed on the roller. A constant velocity universal joint having an R-curved cross-sectional shape having an inner peripheral surface and an inner wall surface of a concave groove as a tangent line.   2. The constant velocity universal joint according to claim 1, wherein the roller has an inner peripheral surface located outside the concave groove and having a larger diameter than an inner peripheral surface located inside the concave groove.   The leg shaft of the tripod member has a substantially elliptical shape in which the long axis is orthogonal to the axis of the joint, and the roller assembly is provided on a ring externally fitted to the outer peripheral surface of the leg shaft via a plurality of rolling elements. The constant velocity universal joint according to claim 1, wherein the roller is rotatably supported.   Tripod member having three axial track grooves formed on the inner periphery, outer joint members having axial roller guide surfaces on both sides of each track groove, and three leg shafts projecting in the radial direction And a roller assembly having a ring-shaped roller that is attached to each leg shaft of the tripod member, swings freely swingable with respect to the leg shaft, and is guided along the roller guide surface. A method for manufacturing a constant velocity universal joint in which an annular concave groove is formed on an inner peripheral surface, and a retaining ring for restricting axial movement of other assembly parts is fitted into the concave groove, and an edge portion of the concave groove Is formed by simultaneous turning of the inner peripheral surface of the roller and the concave groove so that the cross-sectional shape thereof becomes an R curved surface with the inner peripheral surface of the roller and the inner wall surface of the concave groove as a tangent line, etc. A method for manufacturing a universal joint.   The simultaneous turning of the inner peripheral surface of the roller and the concave groove is performed so that the inner peripheral surface located outside the concave groove has a larger diameter than the inner peripheral surface located inside the concave groove. 4. A method for producing a constant velocity universal joint according to 4.   The method for manufacturing a constant velocity universal joint according to claim 5, wherein only the inner peripheral surface of the roller located inside the concave groove is polished.