JP5510129B2 - Sliding tripod type constant velocity joint - Google Patents

Description

  The present invention relates to a sliding tripod type constant velocity joint.

  As a sliding tripod type constant velocity joint, for example, JP-A-10-246241 (Patent Document 1), JP-A-2004-125175 (Patent Document 2), JP-A-2006-162056 (Patent Document 3). There are those described in and etc. The sliding tripod constant velocity joints described in Patent Literatures 1 to 3 are configured such that the tripod shaft portion can swing and swing with respect to the roller. As a result, the direction in which the roller tries to roll on the raceway groove coincides with the direction in which the raceway groove extends, so that no slip can occur between the roller and the raceway groove. As a result, generation of induced thrust force can be reduced.

JP-A-10-246241 JP 2004-125175 A JP 2006-162056 A

  Here, in the sliding tripod type constant velocity joints described in Patent Documents 1 to 3, when the joint angle is taken, the tripod shaft portion slides in the axial direction of the tripod shaft portion with respect to the roller. Therefore, the position where the roller receives force from the tripod shaft changes in the axial direction of the roller. As a result, as described in Patent Document 3, when the roller is viewed from the direction in which the raceway groove of the outer ring extends, the roller swings and swings. Therefore, the non-load side (back side), which is the opposite side of the outer ring raceway groove and the load side that is transmitting torque, contacts the raceway groove, and frictional force is generated between the roller and the raceway groove. May occur. This may affect the generation of induced thrust force.

  The present invention has been made in view of such circumstances, and by reducing the size of the contact load between the track groove on the non-load side and the roller, the sliding force that can reduce the induced thrust force as a result. It aims at providing a dynamic tripod type constant velocity joint.

  (Claim 1) The present invention relating to a sliding tripod type constant velocity joint is connected to a shaft and an outer ring formed in a cylindrical shape and having three raceway grooves formed on an inner peripheral surface extending in the direction of the outer ring rotating shaft. A tripod comprising three tripod shafts that are erected so as to extend radially outward of the boss part from the outer peripheral surface of the boss part and inserted into the track grooves, respectively. A roller formed in an annular shape having a convex arc-shaped outer peripheral surface, rotatably supported on the outer peripheral side of each of the tripod shaft portions and pivotably swingable, and disposed in a rolling manner in the raceway groove; A load transmission point for transmitting torque to and from the outer peripheral surface of the roller is set on the groove side surface of the raceway groove, and among the groove side surfaces of the raceway groove, the tripod type constant velocity joint is provided. Groove opening end from load transmission point The groove opening portion is formed so as to change from a concave portion to a convex portion relative to the outer peripheral surface of the facing roller toward the groove opening end. In this case, the concave portion and the convex portion are set so that the outer peripheral surface of the roller contacts the convex portion without contacting the concave portion.

(Claim 2) In the present invention, the recess is a non-contact groove formed in a direction in which the raceway groove extends, and the convex portion has a shoulder on the groove opening end side of the non-contact groove. It is good also as a site | part to form.
(Claim 3) In the present invention, the curvature and the center of curvature in at least a part of the convex portion may be set to coincide with the curvature and the center of curvature of the load transmission point.
(Claim 4) In the present invention, the recess is formed into a curved surface continuously with the curvature of the load transmission point, and the convex is inside the groove of the track groove with respect to the curved surface of the recess. You may make it protrude and project toward it.

  (Claim 1) According to the present invention, the moment at which the roller receives the force from the tripod shaft portion slides in the axial direction of the roller, and the roller contacts the opening of the non-load side raceway groove. When this occurs in the roller, the outer peripheral surface of the roller contacts the convex portion at the groove opening of the non-load side raceway groove. In the present invention, the groove opening on the groove side surface of the raceway groove is formed so as to change from a concave portion to a convex portion relative to the outer peripheral surface of the opposing roller toward the groove opening end. That is, the convex portion is located on the groove opening end side rather than the concave portion. Moreover, the position where a convex part opposes among rollers is located in the axial direction end surface side among the outer peripheral surfaces of a roller compared with the position which opposes a concave part among rollers.

  Here, in the present invention, the outer peripheral surface of the roller is formed in a convex arc shape. Therefore, the acute angle between the normal line of the outer peripheral surface of the roller and the axial direction of the roller becomes smaller toward the end surface side in the axial direction of the roller in the convex arc shape of the roller. In other words, the acute angle formed between the normal line at the position where the convex portion faces the roller and the axial direction of the roller is smaller than the acute angle formed between the normal line at the position where the convex portion faces and the axial direction of the roller.

  In other words, by providing the recesses and the protrusions as described above, compared with the conventional configuration having no recesses and protrusions, the normal of the point contacting the roller in the raceway groove on the non-load side and the acute angle made with respect to the axial direction of the roller Becomes smaller. By reducing the acute angle, the axial component of the roller in the contact load between the roller and the raceway groove increases, and the axial orthogonal component of the roller in the contact load decreases. As a result, the magnitude of the contact load between the roller and the raceway groove is reduced. Therefore, the induced thrust force is reduced.

(Claim 2) According to the present invention, by setting the groove width of the non-contact groove, the position of the convex portion, that is, the position in contact with the roller can be determined. Therefore, according to the present invention, the concave and convex portions can be easily formed, and the reduction of the induced thrust force can be surely realized.
(Claim 3) According to the present invention, at least a part of the convex portion and the load transmission point are simultaneously formed, and thereafter, the non-contact groove as the concave portion is processed. In this way, it is very easy to form the convex portion.
(Claim 4) According to the present invention, even if the recess is not a shape having both shoulders as in the non-contact groove, but the shape is continuous with the load transmission point, the protrusion is defined with respect to the recess. By projecting, the roller can be surely brought into contact with the convex portion.

1st embodiment: It is a radial direction fragmentary sectional view of a sliding tripod type | mold constant velocity joint, Comprising: The part of one track groove is shown among three track grooves. 1st Embodiment: It is an enlarged view of the outer ring | wheel of the A section of FIG. 1, ie, an expanded sectional view which shows the contact position vicinity with the outer roller in the track groove of the non-load side of an outer ring | wheel. 2nd embodiment: It is an enlarged view of the outer ring corresponding to A part of Drawing 1, ie, an expanded sectional view showing the contact position neighborhood with an outer roller in a raceway groove on the non-load side of an outer ring. Comparative example: FIG. 2 is an enlarged view of an outer ring corresponding to a portion A in FIG. 1, that is, an enlarged cross-sectional view showing the vicinity of a contact position with an outer roller in a non-load-side raceway groove of the outer ring.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the sliding tripod type constant velocity joint of the present invention will be described below with reference to the drawings.

<First embodiment>
The sliding tripod type constant velocity joint of the first embodiment will be described with reference to FIGS. 1 and 2. Here, the case where the sliding tripod constant velocity joint of the present embodiment is used for connecting a power transmission shaft of a vehicle will be described as an example. For example, it is preferably used as an inboard joint of an automobile drive shaft. That is, in this case, the constant velocity joint is used for a connecting portion between the shaft portion connected to the differential gear and the intermediate shaft of the drive shaft.

(Overall configuration of sliding tripod type constant velocity joint)
This sliding tripod type constant velocity joint includes an outer ring 10 connected to a shaft portion (not shown) on the differential gear side, a tripod 20 connected to an intermediate shaft (not shown) on the other side, and an outer ring 10. And a tripod 20 and a roller unit 30 interposed therebetween.

  The outer ring 10 is formed in a cylindrical shape (for example, a bottomed cylindrical shape), and one end side is connected to the differential gear. Three track grooves 11 extending in the outer ring axial direction (front-rear direction in FIG. 1) are formed on the inner peripheral surface of the cylindrical portion of the outer ring 10 at equal intervals in the circumferential direction of the outer ring shaft. The cross-sectional shape of this raceway groove 11 is formed in a Gothic arch shape. Details of the raceway groove 11 of the outer ring 10 will be described later.

  The tripod 20 is disposed inside the cylindrical portion of the outer ring 10. The tripod 20 includes a boss portion 21 and three tripod shaft portions 22. The boss portion 21 is formed in an annular shape, and an internal spline 21 a is formed on the inner peripheral side of the boss portion 21. The internal spline 21a is connected to an external spline (not shown) at the end of the intermediate shaft. Each tripod shaft portion 22 is erected so as to extend from the outer peripheral surface of the boss portion 21 toward the radially outer side of each boss portion 21. These tripod shaft portions 22 are formed at equal intervals (120 ° intervals) in the circumferential direction of the boss portion 21. At least the tip of each tripod shaft portion 22 is inserted into each raceway groove 11 of the outer ring 10. Each tripod shaft portion 22 is formed in a shape that approximates a cylindrical shape as a whole. Specifically, the outer peripheral surface of the tripod shaft portion 22 has a partial spherical shape.

  The roller unit 30 is configured to be annular as a whole. The roller unit 30 is supported on the outer peripheral side of the tripod shaft portion 22 so as to be rotatable around the tripod shaft and slidable in the tripod shaft direction. Further, the roller unit 30 is swingable with respect to the tripod shaft portion 22. Further, the roller unit 30 is arranged to roll along the groove side surface of the raceway groove 11. The roller unit 30 includes an outer roller 31, an inner roller 32, a needle roller 33, and retaining rings 34 and 35.

  The outer roller 31 is formed in an annular shape. The axial cross-sectional shape of the outer peripheral surface of the outer roller 31 is generally formed in a shape corresponding to the groove side surface of the raceway groove 11, that is, a shape obtained by inverting the groove side surface of the raceway groove 11. Specifically, the axial sectional shape of the outer peripheral surface of the outer roller 31 is formed in a convex arc shape represented by a single radius of curvature. The outer roller 31 is inserted into the raceway groove 11 so that its central axis is orthogonal to the outer ring rotation axis. Further, the inner peripheral surface of the outer roller 31 is formed in a cylindrical inner peripheral shape, that is, substantially the same diameter over the axial direction of the outer roller 31. However, retaining ring grooves 31a and 31b are formed on both opening sides of the inner circumferential surface of the outer roller 31 over the entire circumference.

  The inner roller 32 is formed in a cylindrical shape. The axial length of the inner roller 32 corresponds to the distance between the retaining ring grooves 31 a and 31 b formed on the both sides of the outer roller 31. The outer diameter of the inner roller 32 is smaller than the inner diameter of the outer roller 31. The inner roller 32 is spaced apart from the inner side of the outer roller 31 in the radial direction. In the radial gap between the inner roller 32 and the outer roller 31, a plurality of needle rollers 33 are disposed over the entire circumference. The inner roller 32 can rotate relative to the outer roller 31 through the needle roller 33. Further, the inner roller 32 is coaxially disposed radially inward with respect to the outer roller 31. The inner roller 32 is pivotally supported by the tripod shaft portion 22 so as to be rotatable and swingable with respect to the tripod shaft portion 22 and to be slidable in the tripod shaft direction of the tripod shaft portion 22. Yes.

  The retaining rings 34 and 35 are formed in a C-shape having a cut portion so that the diameter can be reduced. These retaining rings 34 and 35 are fitted into retaining ring grooves 31a and 31b of the outer roller 31, respectively. The retaining rings 34 and 35 are hooked in the axial direction of the roller unit 30 with respect to the inner roller 32 and the needle roller 33. That is, the retaining rings 34 and 35 restrict the inner roller 32 and the needle roller 33 from moving relative to the outer roller 31 in the axial direction.

(Detailed configuration of raceway groove 11 of outer ring 10)
Next, the detailed shape of the side surface of the raceway groove 11 of the outer ring 10 will be described with reference to FIGS. 1 and 2. Here, in FIG. 1, when the tripod 20 rotates clockwise in FIG. 1, the groove side on the right side in FIG. 1 of the raceway groove 11 of the outer ring 10 becomes the torque load side, and FIG. The left side surface of the groove is the torque non-load side.

  As described above, the raceway groove 11 is formed in a Gothic arch shape, and the outer peripheral surface of the outer roller 31 is formed in a convex arc shape having a single radius of curvature. Accordingly, as shown in FIG. 1, load transmission points Pf <b> 1 and Pf <b> 2 for transmitting torque between the outer peripheral surface of the outer roller 31 of the roller unit 30 are set on the groove side surface of the raceway groove 11. Thus, in this embodiment, the angular contact where the contact location of the raceway groove | channel 11 and the outer roller 31 becomes two places is employ | adopted.

  Further, as shown in FIGS. 1 and 2, the groove opening located on the groove opening end E side (the lower side in FIG. 1) of the groove side surface of the raceway groove 11 from the load transmission point Pf <b> 2 is the groove opening end E. On the other hand, it is formed so as to change from the concave portion 11a to the convex portion 11b relative to the outer peripheral surface of the opposing outer roller 31. Here, the recess 11 a is a non-contact groove formed in the extending direction of the raceway groove 11 of the outer ring 10. On the other hand, the convex part 11b is a part which forms the shoulder part on the groove opening end E side in the concave part 11a as a non-contact groove. The curvature and the center of curvature of the convex portion 11b are set to coincide with the curvature and the center of curvature of the load transmission point Pf2.

(Load generated in the raceway groove 11 on the non-load side during torque transmission)
Next, the load generated in the track groove 11 on the non-load side during torque transmission will be described with reference to FIGS. In FIG. 2, the load transmission point Pf2 is illustrated, and this indicates a position that becomes the load transmission point Pf2 when the illustrated raceway groove 11 is on the load side. Further, in FIG. 2, a point Pb2 is shown, which indicates a position corresponding to the point Pb2 in the comparative example shown in FIG.

  The case where the tripod 20 rotates clockwise in FIG. 1 and the groove side surface on the right side in FIG. 1 of the raceway groove 11 of the outer ring 10 is the torque load side will be described. Further, as described above, the tripod shaft portion 22 slides with respect to the inner roller 32 in the roller shaft direction. That is, the load point Pt given to the inner peripheral surface of the inner roller 32 by the outer peripheral surface of the tripod shaft portion 22 moves in the axial direction of the inner roller 32. Here, the load generated in the non-load side raceway groove 11 is maximized, that is, the load point Pt is farthest from the turning center Oa in the angular contact to the rotation center side of the outer ring 10 (lower side in FIG. 1). Consider the case of being in position.

  In this case, the roller unit 30 generates a counterclockwise moment in FIG. 1 around the turning center Oa by the load F received from the tripod shaft portion 22. Then, the roller unit 30 contacts in the vicinity of the groove opening on the non-load side of the torque of the raceway groove 11. As described above, the groove opening on the groove side surface of the raceway groove 11 changes from the recess 11a to the protrusion 11b relative to the outer peripheral surface of the opposing outer roller 31 toward the groove opening end E. Is formed. Therefore, in the raceway groove 11 on the non-load side, the outer peripheral surface of the roller unit 30 does not contact the recess 11a of the raceway groove 11 but contacts the point Pb of the projection 11b.

  At this time, the magnitude of the load N generated at the point Pb of the convex portion 11b of the track groove 11 on the non-load side in the present embodiment will be examined. As shown in FIG. 2, the normal direction of the load N at the point Pb coincides with the normal direction of the point Pb and the normal direction of the outer peripheral surface of the outer roller 31 that contacts the point Pb of the convex portion 11b. An acute angle formed by the normal direction and the horizontal direction in FIGS. 1 and 2 is α. The horizontal direction in FIGS. 1 and 2 is a direction orthogonal to the rotation axis of the outer ring 10 and orthogonal to the radial direction of the outer ring 10.

  Consider the balance of moments about the turning center Oa of the roller unit 30. In other words, the moment generated by the load F received by the roller unit 30 from the tripod shaft portion 22 is balanced with the moment generated by the load N received from the convex portion 11 b of the non-load side raceway groove 11. This is represented by equation (1). When this equation (1) is converted with respect to the load N, it is expressed as equation (2). As is clear from the equation (2), the larger the angle α, the larger the denominator of the equation (2), so the load N becomes smaller.

  Here, in order to compare with the present embodiment, as shown in FIG. 4, a case of a raceway groove 211 in which the recess 11 a of the present embodiment is not formed will be described as an example. That is, the groove side surface of the raceway groove 211 shown in FIG. 4 has a shape in which the recess 11a shown by the broken line in FIG. 2 is not formed, that is, the load transmission point Pf2 and the protrusion 11b in FIG. It is assumed that it is formed in a shape connected by a curve with a center of curvature.

  At this time, the magnitude of the load N2 generated at the point Pb2 of the track groove 211 on the non-load side in the comparative example will be examined. As shown in FIG. 4, the normal direction of the load N2 at the point Pb2 coincides with the normal direction of the point Pb2 and the normal direction of the outer peripheral surface of the outer roller 31 in contact with the point Pb2. An acute angle formed by the normal direction and the horizontal direction in FIG. Further, although the distances Lx and Ly shown in FIG. 1 are different from each other, the distances Lx and Ly are considered to be the same because they are very slight differences. Therefore, the load N2 in the comparative example is expressed by Expression (3) in which the angle α in Expression (2) is replaced with the angle β.

  As is clear from a comparison between FIG. 2 and FIG. 3, the angle β in this comparative example is smaller than the angle α in the present embodiment. Then, when comparing the load N derived from Equation (2) with the load N2 derived from Equation (3), the load N represented by a relatively large angle α is represented by a relatively small angle β. It becomes smaller than the load N2. As described above, according to the present embodiment, the recess 11a is formed, and the outer groove 31 is brought into contact with the outer roller 31 at the protrusion 11b on the groove opening end E side than the recess 11a. The load N generated on the side surface of the groove can be reduced. Therefore, the induced thrust force is reduced.

<Second embodiment>
The groove opening of the raceway groove 11 of the outer ring 10 in the second embodiment will be described with reference to FIG. In FIG. 3, the load transmission point Pf2 is illustrated, and this indicates a position that becomes the load transmission point Pf2 when the illustrated raceway groove 11 is on the load side. Further, in FIG. 3, a point Pb2 is shown, which indicates a position corresponding to the point Pb2 in the comparative example shown in FIG.

  In the first embodiment, the non-load groove as the recess 11a is formed so that the curvature and the radius of curvature of the convex portion 11b coincide with the curvature and the radius of curvature of the load transmission point Pf2. In addition, as shown in FIG. 3, in this embodiment, the groove opening of the raceway groove 111 is formed as follows. That is, the recess 111a of the raceway groove 111 is formed in a curved surface continuously with the curvature of the load transmission point Pf2. For example, the curvature and the radius of curvature of the recess 111a are made to coincide with the curvature and the radius of curvature of the load transmission point Pf2. The convex portion 111b of the raceway groove 111 is formed so as to protrude toward the inside of the raceway groove 111 with respect to the curved surface of the recess 111a. That is, the convex portion 111b protrudes toward the inside of the groove from the extended line H of the curved surface of the concave portion 111a. And it contacts with the outer peripheral surface of the outer roller 31 at the point Pb of the convex portion 111b. In this case, the same effect as that of the first embodiment can be obtained.

10: outer ring 11, 111, 211: raceway groove 11a, 111a: recess, 11b, 111b: convex 20: tripod, 21: boss part, 21a: internal spline 22: tripod shaft part 30: roller unit, 31 : Outer roller 31a, 31b: ring groove 32: inner roller 33: needle roller 34, 35: retaining ring 211: raceway groove E: groove opening end, N, N2: load on the non-load side, Oa: moment rotation Centers Pb, Pb2: non-load side contact points, Pf1, Pf2: load transmission points α, β: contact angle, H: extension line of concave curved surface

Claims (4)

An outer ring formed in a cylindrical shape and formed with three raceway grooves extending in the outer ring rotation axis direction on the inner peripheral surface;
A boss portion coupled to the shaft, and three tripod shaft portions that are erected so as to extend radially outward of the boss portion from the outer peripheral surface of the boss portion and are inserted into the raceway grooves, respectively. Tripod,
A roller formed in an annular shape having a convex arc-shaped outer peripheral surface, rotatably supported on the outer peripheral side of each of the tripod shaft portions and pivotably swingable, and disposed in a rolling manner in the raceway groove; ,
A tripod type constant velocity joint comprising:
A load transmission point for transmitting torque to and from the outer peripheral surface of the roller is set on the groove side surface of the raceway groove,
Of the groove side surfaces of the raceway groove, the groove opening portion located closer to the groove opening end side than the load transmission point protrudes from the recess relative to the outer peripheral surface of the roller facing the groove opening end. Formed to change in place,
When the raceway groove is on a non-load side, the outer peripheral surface of the roller is a sliding type in which the recess and the protrusion are set such that the outer surface of the roller contacts the protrusion without contacting the recess. Tripod type constant velocity joint. In claim 1,
The recess is a non-contact groove formed in a direction in which the track groove extends,
The convex portion is a sliding tripod type constant velocity joint which is a portion of the non-contact groove that forms a shoulder on the groove opening end side. In claim 2,
A sliding tripod type constant velocity joint in which a curvature and a center of curvature in at least a part of the convexity are set to coincide with a curvature and a center of curvature of the load transmission point. In claim 1,
The recess is formed in a curved surface continuously with the curvature of the load transmission point,
The convex portion is a sliding tripod constant velocity joint formed so as to protrude toward the inside of the raceway groove with respect to the curved surface of the concave portion.

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