JP2006266325A - Constant velocity universal joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve lubricity of grease in a contact part of each component to enhance durability in the contact part. <P>SOLUTION: The constant velocity universal joint is provided with an outer side joint member 10 which forms three track grooves 12 in an axial direction of an inner periphery and has roller guide surfaces 14 in an axial direction on both sides of each track channel 12 respectively, a tripod member 20 which contains three leg shafts 22 protruding in a radial direction and has a lateral cross section of the leg shaft 22 with a substantially elliptical shape in which a major axis is disposed orthogonal to an axial line of a joint, and roller mechanisms 37 which is respectively mounted on each leg shaft 22 of the tripod member 20 so as to be freely oscillatable with respect to the leg shaft 22. The roller mechanism 37 is an assembly body composed of a roller 34 which is guided in parallel with an axial line of the outer side joint member 10 along the roller guide surface 14 and of a ring 32 which is externally fitted to an outer peripheral surface of the leg shaft 22 and which freely rotatably supports the roller 34 through the medium of a plurality of rolling bodies 36. Oil grooves for holding grease are provided in the outer peripheral surface of the roller 34. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sliding tripod type constant velocity universal joint. 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 the roller is mounted on the outer peripheral surface of the leg shaft via a plurality of needle rollers. The outer joint member and the tripod member rotate while taking an operating angle. When torque is transmitted, each roller and the roller guide surface are in an oblique state with the inclination of the leg shaft, so that slip occurs between them and smooth rolling of each roller is hindered and induced. There is a problem that the thrust becomes large. 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.

  A tripod equipped with a roller mechanism that allows the roller to tilt and displace axially in order to eliminate the problem that the roller and the roller guide surface are in an oblique state and to reduce induced thrust and slide resistance. Various types of constant velocity universal joints have been proposed.

  As this type of tripod constant velocity universal joint, a roller is rotatably assembled to a ring via a plurality of needle rollers to form a roller mechanism (roller assembly), and the inner peripheral surface of the ring is formed into an arcuate convex cross section A configuration in which the outer periphery of the leg shaft is externally fitted is known (see, for example, 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 mechanism 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.

  Further, the cross-sectional shape of the leg shaft is in contact with the inner peripheral surface of the ring in a direction perpendicular 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. The shape is an ellipse, for example.

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 mechanism. 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 mechanism is reduced. Therefore, the posture of the roller mechanism is always stable and the roller is held in parallel with the roller guide surface, so that it can roll smoothly.
JP 2000-320563 A

  By the way, the tripod type constant velocity universal joint described above employs a roller mechanism to reduce the induced thrust and slide resistance that cause the vibration and noise of the vehicle body, and the cross-sectional shape of the leg shaft is elliptical. By doing so, the roller mechanism can swing freely even if the operating angle is taken, and the roller mechanism can smoothly roll 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.

  However, the contact portion of each component in this tripod type constant velocity universal joint, in particular, the convex curved outer peripheral surface of the roller mechanism of the roller mechanism that contacts the roller guide surface of the outer joint member, is a concave curved roller guide surface. Because of the contact, the surface pressure at the contact portion between the outer peripheral surface of the roller and the roller guide surface is high, and it is necessary to improve the lubrication of the grease in order to improve the durability at the contact portion.

  Therefore, the present invention has been proposed in view of the above-described necessity, and the object of the present invention is to improve the lubricity of grease at the contact portion of each component and improve the durability at the contact portion. The object is to provide a constant velocity universal joint.

  As a technical means for achieving the above-mentioned object, the present invention provides an outer joint in which three track grooves in the axial direction are formed on the inner peripheral portion, and axial roller guide surfaces are provided on both sides of each track groove. A tripod member having a member and three leg shafts projecting in the radial direction, the major axis of which is a substantially elliptical shape whose major axis is perpendicular to the axis of the joint, and each leg shaft of the tripod member A roller mechanism that is mounted and swingable with respect to the leg shaft, the roller mechanism being guided in a direction parallel to the axis of the outer joint member along the roller guide surface, and the leg shaft In a constant velocity universal joint that is an assembly body composed of a ring that is fitted around the outer peripheral surface of the roller and rotatably supports the roller via a plurality of rolling elements, grease is held on the outer peripheral surface of the roller. Features an oil groove That.

  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.

  In the above-described configuration, since the outer peripheral surface of the roller is in angular contact with the roller guide surface of the outer joint member, the oil groove is along the circumferential direction at two contact sites that are in angular contact with the roller guide surface of the outer joint member. It is desirable to form in an annular shape. Note that the oil groove may be formed in an annular shape along the circumferential direction at an axially central portion located between two contact portions that are in angular contact with the roller guide surface of the outer joint member.

  In the constant velocity universal joint according to the present invention, an oil groove for retaining grease is provided on the outer peripheral surface of the roller, so that the grease lubricity at the contact portion between the outer peripheral surface of the roller and the roller guide surface of the outer joint member is improved. It is possible to improve the durability at the contact portion. In addition, if the edge part of an oil groove is made into the smooth shape, for example, R surface by R chamfering process, grease lubrication will be performed much more smoothly.

  According to the present invention, by providing an oil groove for holding grease on the outer peripheral surface of the roller, the lubricity of the grease at the contact portion between the outer peripheral surface of the roller and the roller guide surface of the outer joint member is improved. The durability at the contact portion can be improved, the operability can be improved, and the life of the constant velocity universal joint can be easily realized.

  The embodiment of the tripod type constant velocity universal joint 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 mechanism of the constant velocity universal joint, and FIG. 4 shows the overall configuration of the roller mechanism. 1 to 4 show a general tripod type constant velocity universal joint in which the oil groove is omitted, and the oil groove is specifically illustrated in FIGS. 5 to 7.

  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 an outer peripheral surface 34 a of the roller 34 forms a convex curved surface that fits the roller guide surface 14. .

  The outer peripheral surface 34a 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 Gothic having two radii of curvature. An arch shape is formed, whereby the outer peripheral surface 34a 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 34a of the convex curved surface of the roller 34, the angular contact between them is realized.

  As described above, the angular contact between the outer peripheral surface 34a of the roller 34 and the roller guide surface 14 makes the roller 34 less likely to shake, so that the posture can be stabilized. In the case where 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 34 a of the roller 34. It can also be an arc corresponding to.

  The outer peripheral surface 22a 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 32b 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, since the cross section of the leg shaft 22 is substantially elliptical and the cross section of the inner peripheral surface 32b of the ring 32 is an arcuate convex cross section, the contact ellipse of both is close to a point, At the same time, the area becomes smaller. Therefore, the force for tilting the roller mechanism 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.

  A ring 32 is fitted on the outer peripheral surface 22 a 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 mechanism 37 (roller assembly) capable of relative rotation. That is, the cylindrical outer peripheral surface 32a of the ring 32 is used as an inner raceway surface, and the cylindrical inner peripheral surface 34b of the roller 34 is used as an outer raceway surface. 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, the needle roller 36 and the roller 34 in the axial direction thereof, locking means are provided on both sides in the axial direction of the roller mechanism 37. As this locking means, as shown in FIG. 4, a retaining ring 35 is fitted in an annular groove 33 provided on the inner peripheral surface 34 b of the roller 34. 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.

  Here, the contact portion of each component in this tripod type constant velocity universal joint, in particular, the convex curved outer peripheral surface 34a of the roller 34 contacting the roller guide surface 14 of the outer joint member 10 is a concave curved roller guide. Since it is in contact with the surface 14, the surface pressure at the contact portion between the outer peripheral surface 34a of the roller 34 and the roller guide surface 14 is high, and it is necessary to improve the lubrication of the grease in order to improve the durability at the contact portion. is there.

  Therefore, as shown in FIG. 5, an annular oil groove 48 is formed along the circumferential direction of the outer peripheral surface 34 a of the roller 34. By providing the oil groove 48 on the outer peripheral surface 34a of the roller 34 in this way, the lubricity of grease at the contact portion between the outer peripheral surface 34a of the roller 34 and the roller guide surface 14 is improved, and the durability at the contact portion is improved. Can be improved.

  In FIG. 5, the oil groove 48 is formed in the axial central portion of the outer peripheral surface 34 a of the roller 34, but the outer peripheral surface 34 a of the roller 34 is in angular contact with the roller guide surface 14 at two points. As shown in FIG. 6, it is desirable to provide annular oil grooves 48 along the circumferential direction at two contact portions that make angular contact.

  In addition, as for the oil groove 48 demonstrated above, it is desirable to make the edge part 50 smooth by chamfering processes, such as R surface processing, as shown in FIG. By smoothing the edge portion 50 of the oil groove 48 in this manner, grease lubrication is performed more smoothly.

  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 mechanism of FIG. It is a front view which shows the roller which provided the one oil groove in the circumferential direction of the outer peripheral surface. It is a front view which shows the roller which provided the two oil grooves in the circumferential direction of the outer peripheral surface. It is a principal part expanded sectional view which shows the oil groove which made the edge part smooth.

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 34 Roller 34a Outer peripheral surface 36 Rolling element (needle roller)
37 Roller mechanism 48 Oil groove 50 Edge

Claims (4)

  Three track grooves in the axial direction are formed on the inner peripheral portion, and an outer joint member having an axial roller guide surface on each side of each track groove, and three leg shafts projecting in the radial direction, A tripod member whose transverse axis is substantially elliptical with the major axis orthogonal to the axis of the joint, and a roller mechanism that is mounted on each leg shaft of the tripod member and swings freely with respect to the leg shaft The roller mechanism includes a roller that is guided along a roller guide surface in a direction parallel to the axis of the outer joint member, and the roller mechanism that is externally fitted to the outer peripheral surface of the leg shaft via a plurality of rolling elements. A constant velocity universal joint that is an assembly composed of a ring that rotatably supports a roller, and an oil groove that holds grease is provided on an outer peripheral surface of the roller.   2. The constant velocity universal joint according to claim 1, wherein the oil groove is formed in an annular shape along a circumferential direction at two contact portions that are in angular contact with the roller guide surface of the outer joint member.   2. The constant velocity freely according to claim 1, wherein the oil groove is formed in an annular shape along a circumferential direction at an axially central portion located between two contact portions that are in angular contact with the roller guide surface of the outer joint member. Fittings.   The said oil groove is a constant velocity universal joint as described in any one of Claims 1-3 in which the edge part has a smooth shape.

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