JP5287519B2 - Sliding tripod type constant velocity joint - Google Patents

Description

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

  As a conventional sliding tripod type constant velocity joint, for example, there is one described in Japanese Patent Laid-Open No. 2005-98402 (Patent Document 1). The sliding tripod type constant velocity joint described in Patent Document 1 has a cylindrical outer ring having three raceway grooves formed on the inner peripheral surface, and three tripod shaft portions inserted into the raceway grooves. A tripod, a roller inserted in each raceway groove, an intermediate member (ring) that is externally fitted to each tripod shaft portion and rotatably supports each roller, and is rotatably interposed between the roller and the ring. Rolling elements (balls). When power is transmitted with this configuration, a large resistance is generated by slippage in addition to rolling resistance between the rolling element and the intermediate member and between the rolling element and the roller.

  Therefore, in order to reduce this resistance, for example, there is one described in Japanese Patent No. 2763624 (Patent Document 2). The sliding tripod type constant velocity joint described in Patent Document 2 uses a rolling element as a needle and eliminates the roller described above, so that the rolling element rolls in the raceway groove, and the rolling element is in the middle. It is comprised so that the outer periphery of a member (block) may be supported by the holder | retainer so that circulation is possible. Thereby, the resistance by the sliding between a rolling element and an intermediate member, and a rolling element and a raceway groove | channel can be reduced significantly.

JP-A-2005-98402 Japanese Patent No. 2763624

  By the way, the constant velocity joint described in Patent Document 2 is of a needle circulation type configured such that the needle circulates around the outer periphery of the intermediate member. In this type of constant velocity joint, when power is transmitted, the intermediate member reciprocates in the outer ring radial direction by following the movement of the tripod shaft portion in the outer ring rotation axis direction and sliding on the contact surface with the needle. It is a structure. In this case, since it is necessary to position the intermediate member and the tripod shaft portion, the intermediate member is externally fitted in a spherical contact with the tripod shaft portion. That is, the outer peripheral surface of the tripod shaft part is formed to have a part of the convex spherical surface, and the inner peripheral surface of the intermediate member has a part of the concave spherical surface that matches the convex spherical surface of the tripod shaft part. Is formed.

  Normally, the convex spherical shape of the tripod shaft is thickened by pressing the tip of the shaft-like rough material against the die when making it by forging, which increases the cost due to the deterioration of the die life. There is a problem of inviting. Further, the intermediate member needs to be formed so that the spherical center of the concave spherical surface and the spherical center of the convex spherical surface of the tripod shaft part coincide with each other, and high dimensional accuracy is required. This leads to higher costs.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to solve the problem of cost reduction in a needle circulation type sliding tripod type constant velocity joint.

In order to solve the above problem, the feature of the invention according to claim 1 is:
An outer ring having 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,
An intermediate member provided on the outer periphery of the tripod shaft portion so as to be swingable with respect to the tripod shaft portion, and having an outer power transmission surface facing the side surface of the raceway groove on the outer surface;
A plurality of axial rolling elements provided between the side surface of the raceway groove and the outer power transmission surface so as to roll along the side surface of the raceway groove;
A cage that supports the shaft-like rolling element so that the shaft-like rolling element can circulate around the outer periphery of the intermediate member;
With
The cross-sectional shape in the axial direction of the tripod shaft portion of the outer peripheral surface of the tripod shaft portion is formed in a straight shape,
On the inner peripheral surface of the intermediate member, a protruding portion that protrudes inward in the radial direction of the tripod shaft and extends in the circumferential direction is provided .
The inner power transmission surface that transmits power by contacting the tripod shaft portion of the ridge portion has a straight cross-sectional shape in a direction perpendicular to the axial direction of the tripod shaft portion .

Feature of the invention according to claim 2, Oite to claim 1, the cross-sectional shape in the axial direction of the tripod shaft part of the projecting distal end face of the protruding portion, is in an arc shape is convex in the protruding direction It is that you are.

A feature of the invention according to claim 3 is that, in claim 2 , the arcuate cross-sectional shape of the protruding tip surface is the same in the entire circumferential direction of the tripod shaft portion.

A feature of the invention according to claim 4 is that, in claim 2 , the radius of curvature of the arc surface forming the inner power transmission surface of the protruding tip surface is an arc forming the protruding tip surface other than the inner power transmission surface. The radius of curvature of the surface is larger.

A feature of the invention according to claim 5 is that in any one of claims 1 to 4 ,
A track recess that extends in the extending direction of the track groove is formed on a surface of the intermediate member that faces the side surface of the track groove.
The shaft-like rolling element is provided such that a portion of the shaft-like rolling element located on the intermediate member side is fitted into the track recess and is rollable along the bottom surface of the track recess.

According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the intermediate member is disposed in a separated state so as to sandwich the tripod shaft portion from both sides of the side surface of the raceway groove. It is that it is comprised by the division member of.

A feature of the invention according to claim 7 is that, in any one of claims 1 to 6 , the tripod shaft portion is formed in a columnar shape.

A feature of the invention according to claim 8 is that, in any one of claims 1 to 7 , a protrusion for preventing the intermediate member from falling off is provided at a tip portion of the tripod shaft portion.

  According to the invention according to claim 1 configured as described above, the cross-sectional shape in the axial direction of the tripod shaft portion of the outer peripheral surface of the tripod shaft portion is formed in a straight shape. Thereby, when the tripod is produced by forging, it is not necessary to form a convex spherical surface on the outer peripheral surface of the tripod shaft portion as in the prior art, so that the die life can be improved and the cost can be reduced. Moreover, according to this invention, the protrusion part which protrudes in the radial inside of a tripod shaft part and extends in the circumferential direction is provided in the inner peripheral surface of the intermediate member. As a result, there is no need to form a concave spherical surface on the inner peripheral surface of the intermediate member as in the prior art, so the shape of the intermediate member can be simplified and the cost can be reduced.

According to the first aspect of the present invention, the inner power transmission surface that transmits power by contacting the tripod shaft portion of the ridge portion has a straight cross-sectional shape in a direction orthogonal to the axial direction of the tripod shaft portion. ing. Thereby, when power is transmitted from the tripod shaft portion to the intermediate member, the tripod shaft portion that reciprocates (swings) in the direction of the outer ring rotation shaft can be smoothly moved.

According to the invention which concerns on Claim 2 , the cross-sectional shape in the axial direction of the tripod shaft part of the protrusion front end surface of a protrusion part is made into the circular arc shape convex in the protrusion direction. That is, according to the present invention, the cross-sectional shape in the axial direction of the tripod shaft portion is formed in an arc shape that is convex in the projecting direction with respect to the tripod shaft portion in which the axial cross-sectional shape is formed in a straight shape. It is comprised so that the protrusion front end surface of the protruding ridge part may contact in the state which crossed. Thereby, when power is transmitted from the tripod shaft portion to the intermediate member, the tripod shaft portion that swings in a direction perpendicular to the outer ring rotation axis can be made smooth.

According to the invention of claim 3 , since the arcuate cross-sectional shape of the protruding tip surface is the same in the entire circumferential direction of the tripod shaft portion, the intermediate member can be easily processed and the processing cost is reduced. be able to.

According to the invention which concerns on Claim 4 , the curvature radius of the circular arc surface which forms the inner side power transmission surface of a protrusion front end surface is made larger than the curvature radius of the circular arc surface which forms the protrusion front end surface other than an inner side power transmission surface. Yes. Thereby, the surface pressure of the inner side power transmission surface of the protrusion part which contacts a tripod shaft part can be reduced.

According to the invention which concerns on Claim 5 , the track | surface recessed part extended in the circumferential direction of a tripod shaft part is formed in the surface facing the side surface of the track groove of an intermediate member, and a shaft-shaped rolling element is an intermediate | middle of a shaft-shaped rolling element. A portion located on the member side is fitted into the track recess and is provided so as to roll along the bottom surface of the track recess. Thereby, when the force which tries to move to the axial rolling element by the skew generate | occur | produces in the axial direction, the said movement of an axial rolling element can be controlled by a track | orbit recessed part. Note that the skew is a state in which the axial center of the axial rolling element is inclined with respect to the rolling direction of the axial rolling element. When the skew is generated in the shaft-like rolling element, a force in the axial direction is generated in the shaft-like rolling element.

According to the invention of claim 6 , the intermediate member is constituted by two separated members. By doing in this way, an intermediate member can be easily assembled | attached to a tripod axial part. Further, by configuring the intermediate member with two separated members, contact between the intermediate member and the raceway groove of the outer ring can be suppressed on the back side of the surface where power is transmitted. Further, as described above, even if the intermediate member is divided into two divided members, the intermediate member and the cage can be fitted to the outer peripheral surface of the tripod shaft portion so that the intermediate member and the cage can be fitted to the tripod shaft portion. Can be prevented from leaving.

According to the invention which concerns on Claim 7 , the tripod axial part is formed in the column shape. As a result, the shape of the tripod shaft is simplified, and necessary machining is minimized, so that machining costs can be reduced.

According to the eighth aspect of the present invention, the protrusion that prevents the intermediate member from falling off is provided at the tip of the tripod shaft. Thereby, when an intermediate member, a shaft-like rolling element, and a holder | retainer are assembled | attached with respect to each tripod shaft part, it can prevent that an intermediate member etc. fall out from a tripod shaft part.

It is a perspective view of the constant velocity joint 1, and shows the state where the outer ring 10 is cut in the axial direction. FIG. 3 is a view seen from the opening side of the outer ring 10 in a partly assembled state of the constant velocity joint 1. FIG. 3 is a radial sectional view of a part of the constant velocity joint 1. 4 is a perspective view of only a split member 41 of the intermediate member 40. FIG. 4 is a plan view of only a split member 41 of the intermediate member 40. FIG. (A): It is AA sectional drawing of the division member 41 shown in FIG. (B): It is BB sectional drawing of the division member 41 shown in FIG. FIG. 5 is a perspective view of a state in which a shaft-like rolling element 50 is assembled to a cage 60. (A): It is a front view of the cage 60. (B): It is CC sectional drawing of (a). (C): It is DD sectional drawing of (a). It is a top view of only the division member 41 of the intermediate member 40 which concerns on other embodiment. (A): It is EE sectional drawing of the division member 41 shown in FIG. (B): It is FF sectional drawing of the division member 41 shown in FIG.

  Hereinafter, an embodiment in which the sliding tripod type constant velocity joint of the present invention (hereinafter simply referred to as “constant velocity joint”) is embodied will be described with reference to FIGS. Here, the case where the constant velocity joint of this embodiment is used for connection of a power transmission shaft of a vehicle will be described as an example. For example, it is a case where it uses for the connection part of the axial part connected with the differential gear, and the intermediate shaft of a drive shaft.

  As shown in FIGS. 1 to 3, the constant velocity joint 1 includes an outer ring 10, a tripod 20, and a needle unit 30.

  As shown in FIG. 1, the outer ring 10 includes a cylindrical portion 11 and a connecting shaft portion 12. The cylindrical part 11 is formed in a bottomed cylindrical shape. The connecting shaft portion 12 is coaxially and integrally formed with the tubular portion 11 so as to extend axially outward from the bottom portion of the tubular portion 11. The connecting shaft portion 12 is connected to a differential gear (not shown).

  As shown in FIGS. 1 to 3, track grooves 16 extending in the outer ring rotating shaft direction (front-rear direction in FIG. 2) are formed on the inner peripheral surface of the cylindrical portion 11 at equal intervals in the circumferential direction of the outer ring rotating shaft. Three are formed. The cross-sectional shape orthogonal to the groove extending direction in each raceway groove 16 forms a U-shape that opens toward the center of the rotation axis of the outer ring 10. That is, each track groove 16 includes a groove bottom surface 161 formed in a substantially planar shape, and side surfaces 162 and 163 formed in a substantially planar shape orthogonal to the groove bottom surface 161 and facing each other in parallel.

  Track recesses 17 and 18 extending in the direction of the outer ring rotation axis are formed on the side surfaces 162 and 163, respectively. The track recesses 17 and 18 are formed at substantially the center in the radial direction of the outer ring 10 among the side surfaces 162 and 163 of the track groove 16. The opening width (the vertical width in FIGS. 2 and 3) of the track recesses 17 and 18 is formed so as to gradually increase toward the opening side. That is, the track recesses 17 and 18 have substantially flat bottom surfaces 17a and 18a and inclined side surfaces 17b and 18b.

  As shown in FIGS. 1 and 3, the tripod 20 is disposed inside the cylindrical portion 11 of the outer ring 10. The tripod 20 includes a boss portion 21 and three tripod shaft portions 22. The boss portion 21 has an annular shape, and an internal spline 21a is formed on the inner peripheral side thereof. The internal spline 21a is fitted and connected to the external spline at the end of the intermediate shaft 2. Moreover, the outer peripheral surface of the boss | hub part 21 is formed in the substantially spherical convex shape.

  Each tripod shaft portion 22 is erected so as to extend from the outer peripheral surface of the boss portion 21 outward in the radial direction of the boss portion 21. These tripod shaft portions 22 are formed at equal intervals (120 deg intervals) in the circumferential direction of the boss portion 21. And at least the front-end | tip part of each tripod shaft part 22 is inserted in each track groove 16 of the cylindrical part 11 of the outer ring | wheel 10. As shown in FIG.

  Each tripod shaft portion 22 is formed in a columnar shape, and a ring-shaped protrusion 22a that protrudes radially outward from the outer peripheral surface and continuously extends in the circumferential direction is provided at the tip portion thereof. When the needle unit 30 (the intermediate member 40, the shaft-shaped rolling element 50, and the retainer 60) is assembled to each tripod shaft portion 22, the protrusion 22a is detached from the tripod shaft portion 22. To prevent. The cross-sectional shape in the axial direction of each tripod shaft portion 22 is formed in a straight shape except for the protrusion 22a. Here, the rotation axis of the tripod 20 (rotation axis of the intermediate shaft 2) and the central axis of the tripod shaft portion 22 (hereinafter also referred to as “tripod axis”) are orthogonal to each other.

  As shown in FIG. 1, the needle unit 30 has an annular shape as a whole, and is disposed on the outer peripheral side of the tripod shaft portion 22. Further, the needle unit 30 is fitted into the raceway groove 16 so as to be movable in the direction in which the raceway groove 16 extends. The needle unit 30 includes an intermediate member 40, a plurality of rolling elements 50, and a cage 60.

  As shown in FIGS. 1 and 3, the intermediate member 40 includes a pair of split members 41 and 42. When the pair of divided members 41 and 42 are viewed integrally, the outer shape of the intermediate member 40 as an overall shape is substantially rectangular. Furthermore, when the intermediate member 40 is viewed as a whole, a portion corresponding to a circular hole is formed at the center of the intermediate member 40.

  The pair of divided members 41 and 42 are separately provided so as to have a plane-symmetric shape with respect to a plane passing through the tripod shaft (vertical direction in FIG. 3) and the rotation axis of the intermediate shaft 2 (front and rear direction in FIG. 3). Configured and independent of each other. Then, as shown in FIGS. 1 and 3, the pair of split members 41 and 42 are disposed so as to sandwich the tripod shaft portion 22 from both sides of the side surfaces 162 and 163 of the raceway groove 16. That is, both the split members 41 and 42 are disposed so as to sandwich the tripod shaft portion 22 from both sides in the power transmission direction (the direction around the outer ring rotation axis or the intermediate shaft rotation axis). The pair of divided members 41 and 42 are provided so as to be swingable with respect to the tripod shaft portion 22 when viewed from all directions orthogonal to the tripod shaft portion 22.

  Here, with reference to FIGS. 4-6, the detailed shape of the division member 41 is demonstrated. Since the other divided member 42 is made symmetrical with the one divided member 41 as described above, detailed description thereof is omitted.

  The dividing member 41 is formed in a rectangular block shape. The peripheral surface of the split member 41 is formed in a projecting tip surface 43 a and an inclined surface 43 b that project inward in the radial direction of the tripod shaft portion 22 and extend in the circumferential direction, and in the track recess 44. It has an outer power transmission surface 44a and end surfaces 41a and 41b in the tripod rotation axis direction. Here, when the intermediate member 40 is viewed as a unit, the protruding tip surface 43a and the inclined surface 43b of the protrusion 43 form an inner peripheral surface, and the outer power transmission surface 44a and the axial end surfaces 41a and 41b are outer peripheral surfaces. Form.

  The protruding portion 43 is formed in a triangular mountain shape having a protruding tip surface 43a formed at the center in the tripod axis direction and inclined surfaces 43b continuous on both sides of the protruding tip surface 43a. The protruding front end surface 43a has an inner power transmission surface 43c that contacts the tripod shaft portion 22 and transmits power at the center in the rotation axis direction. The inner power transmission surface 43c is formed so that a cross-sectional shape in a direction orthogonal to the axial direction of the tripod shaft portion 22 is a straight shape. The straight length L of the inner power transmission surface 43c is set in correspondence with the movable range of the tripod shaft 22 that swings in the direction of the outer ring rotation axis when power is transmitted from the tripod shaft 22 to the intermediate member 40. Has been. A backlash is provided between the inner power transmission surface 43c and the outer peripheral surface of the tripod shaft portion 22 so that the swing motion of the tripod shaft portion 22 is possible.

  The protruding tip surface 43a is a cross-sectional shape in the axial direction of the tripod shaft portion 22 so as to come into contact with the tripod shaft portion 22 so as to be swingable when viewed from all directions orthogonal to the tripod shaft portion 22. Is formed in an arc shape that is convex in the protruding direction. As shown in FIGS. 5 and 6, the curvature radius R1 of the arc surface forming the inner power transmission surface 43c of the projecting tip surface 43a is the arc surface forming the projecting tip surface 43a other than the inner power transmission surface 43c. Is larger than the curvature radius R2. Thereby, the surface pressure of the inner side power transmission surface 43c which contacts the tripod shaft part 22 at the time of power transmission is reduced.

  The outer power transmission surface 44a is formed by the bottom surface of the track recess 44 provided on the back surface side of the inner power transmission surface 43c, that is, the surface on the right front side in FIG. 4 (the surface facing the side surfaces 162 and 163 of the track groove 16). ing. That is, the track recess 44 and the outer power transmission surface 44 a are formed on the surface facing the side surfaces 162 and 163 of the track groove 16 so as to extend in the extending direction of the track groove 16.

  The opening width of the track recess 44 (the vertical width in FIGS. 2 and 3) is formed so as to gradually increase toward the opening. That is, the track recess 44 has a substantially planar outer power transmission surface (bottom surface) 44a and an inclined side surface 44b. The track recess 44 is provided at a position facing the track recesses 17 and 18 provided in the track groove 16. The outer power transmission surface 44a is substantially flat and rectangular. Both ends of the outer power transmission surface 44a in the direction of the outer ring rotating shaft are formed to be slightly curved. That is, the central portion of the outer power transmission surface 44a protrudes most outward in the left-right direction in FIG.

  Each split member 41 is arranged such that the outer power transmission surface 44a of one split member 41 faces the side surface 162 of the raceway groove 16 substantially in parallel. Similarly, with respect to the other divided member 42, the divided member 42 is disposed so that the outer power transmission surface faces the side surface 163 of the raceway groove 16 substantially in parallel. That is, in a posture in which the rotation axis of the outer ring 10 and the rotation axis of the intermediate shaft 2 coincide (joint angle 0 deg), the outer power transmission surface 44a passes through the central axis of the tripod shaft portion 22 and the rotation axis of the intermediate shaft 2. Almost parallel to the plane. And the outer side power transmission surface 44a has the range which can contact the plurality of (in this embodiment, 3-4 pieces) axial rolling element 50. FIG.

  The end surfaces 41a and 41b in the tripod rotation axis direction are portions located at the left front side and the right back side in FIG. The both end faces 41a and 41b are flat surfaces that are substantially orthogonal to the outer power transmission surface 44a. That is, both end surfaces 41 a and 41 b are flat surfaces that are substantially orthogonal to the side surface 162 of the raceway groove 16.

  The shaft-like rolling element 50 is a needle as shown in FIGS. And as shown in FIG. 1, the some axial rolling element 50 is provided so that the outer periphery at the time of seeing the intermediate member 40 as integral may be circulated. A part (three to four in this embodiment) of the plurality of shaft-like rolling elements 50 is the outer power of the bottom surfaces 17a and 18a of the track recesses 17 and 18 of the track groove 16 and the pair of split members 41 and 42. It is provided between the transmission surface 44a so as to roll along the bottom surfaces 17a and 18a and the outer power transmission surface 44a. That is, power is transmitted between the outer power transmission surface 44 a and the bottom surfaces 17 a and 18 a of the raceway groove 16 via the shaft-shaped rolling element 50.

  The axial rolling element 50 has a cylindrical rolling surface portion 51 having a rolling surface 51a on the outer periphery, a circular section cut in the direction perpendicular to the column extension (left and right direction in FIG. 2), and the axis of the rolling surface portion 51. And protrusions 52 respectively protruding from both end faces in the direction. The column extending length of the rolling surface 51a formed on the outer peripheral surface of the rolling surface portion 51 is equal to the width of the bottom surface 17a, 18a of the track recesses 17, 18 and the outer power transmission surface 44a of the track recess 44, or the bottom surface. The width is set to be slightly shorter than the width of the portions 17a and 18a.

  Both end surfaces of the rolling surface portion 51 are formed in a tapered shape. The tapered end surface 51 b has substantially the same taper shape as the side surfaces 17 b and 18 b of the track recesses 17 and 18 and the side surface 44 b of the track recess 44. That is, in the rolling surface portion 51, a portion of the rolling surface portion 51 located on the bottom surface 17 a, 18 a side of the raceway concave portion 17, 18 is fitted into the raceway concave portion 17, 18 and the outer power of the raceway concave portion 44 of the rolling surface portion 51. A portion located on the transmission surface (bottom surface) 44 a side is provided so as to be fitted into the track recess 44.

  More specifically, the tapered end surface 51 b can be engaged with the side surfaces 17 b and 18 b of the track recesses 17 and 18 and the side surface 44 b of the track recess 44 in the axial direction of the axial rolling element 50. That is, in the axial rolling element 50, the movement of the axial rolling element 50 in the axial direction is restricted by the track recesses 17 and 18 and the track recess 44. The rolling surface 51 a on the outer periphery of the rolling surface portion 51 can roll along the bottom surfaces 17 a and 18 a of the track recesses 17 and 18 and the outer power transmission surface 44 a of the track recess 44.

  The protrusion 52 is formed with a smaller diameter than the outer diameter of the rolling surface portion 51. The distance between the tips of the protrusions 52 on both sides, that is, the axial length of the axial rolling element 50 is formed larger than the opening widths of the track recesses 17 and 18 and the track recess 44. That is, the protrusion 52 is located outside the track recesses 17 and 18 and the track recess 44.

  As shown in FIG. 7 and FIGS. 8A to 8C, the cage 60 has an annular shape as a whole. The cage 60 supports the shaft-like rolling element 50 so that the shaft-like rolling element 50 can circulate around the outer periphery of the intermediate member 40. The cage 60 is substantially accommodated in the raceway groove 16. The cage 60 includes a pair of circulation path forming members 61 and 62 that form a circulation path of the shaft-like rolling element 50 and a pair of connecting portions 63 and 64 that couple the pair of circulation path forming members 61 and 62. Is done.

  The pair of circulation path forming members 61 and 62 is located on the periphery of the cage 60 and has an oval shape. The pair of circulation path forming members 61 and 62 has a shape surrounding the pair of divided members 41 and 42. Specifically, the circulation path forming member 61 includes linear portions 61a and 61b facing each other and semicircular arc-shaped curved portions 61c and 61d connecting the linear portions 61a and 61b. The other circulation path forming member 62 is composed of a straight portion and a curved portion, like the circulation path forming member 61.

  Further, the pair of circulation path forming members 61 and 62 are disposed to face each other so as to sandwich the axial rolling element 50 in the axial direction. Each of the pair of circulation path forming members 61 and 62 has a U-shaped cross-sectional shape in which the protrusion 52 of the shaft-like rolling element 50 is inserted and engages with the tapered end surface 51 b of the rolling surface 51. Is formed. In this way, the pair of circulation path forming members 61 and 62 supports both protrusions 52. That is, the radial width (the distance between the inner peripheral edge and the outer peripheral edge) of the pair of circulation path forming members 61 and 62 is formed to be smaller than the maximum diameter of the rolling surface portion 51 of the axial rolling element 50. Accordingly, the rolling surface portion 51 of the shaft-shaped rolling element 50 protrudes outward from the outer peripheral edge of the pair of circulation path forming members 61 and 62 and also extends inward from the inner peripheral edge of the pair of circulation path forming members 61 and 62. It protrudes.

  The U-shaped opening sides of the respective circulation path forming members 61 and 62 are provided so as to face each other with a distance slightly longer than the axial length of the rolling surface portion 51 of the shaft-like rolling element 50. ing. Therefore, the maximum width in the opposing direction of the pair of circulation path forming members 61 and 62 is set to be larger than the respective opening widths of the track recesses 17 and 18 and the track recess 44. The pair of circulation path forming members 61 and 62 are housed inside the raceway groove 16 and are located outside the raceway recesses 17 and 18 and the raceway recess 44.

  Further, the distance between the straight portions 61a and 61b of the pair of circulation path forming members 61 and 62 is set to be smaller than the groove width of the raceway groove 16 (distance between the opening of the raceway recess 17 and the opening of the raceway recess 18). Has been. That is, the pair of circulation path forming members 61 and 62 are disposed with a gap from the side surfaces 162 and 163 of the raceway groove 16.

  A pair of connection parts 63 and 64 connect the circumferential direction center part (upper and lower end parts in FIG. 8A) of the curved parts 61c and 61d of the pair of circulation path forming members 61 and 62, respectively. In other words, the space between the pair of circulation path forming members 61 and 62 is open at a portion other than the connecting portions 63 and 64.

  As shown in FIG. 8C, the connecting parts 63 and 64 are formed in a U-shape that opens to the outside of the cage 60. The U-shaped bottom opening opposite side of the connecting portions 63 and 64 (inside the retainer 60, hereinafter referred to as “bottom inner side surface”) is formed in a planar shape. And the inner surface of the bottom part of a pair of connection parts 63 and 64 is provided so that it may oppose in parallel. Further, the separation distance between the bottom inner surfaces of the pair of connecting portions 63 and 64 is substantially equal to the distance between the end surfaces 41a and 41b of the divided members 41 and 42 in the tripod rotation axis direction. Further, the U-shaped bottom opening side of the connecting portions 63 and 64 (outside of the retainer 60, hereinafter referred to as “bottom outer side surface”) is formed in a planar shape parallel to the bottom inner side surface.

  In addition, one of the end portions of the connection portions 63 and 64 on the opening side of the U-shape is connected to the respective circumferential center portions of the curved portions 61c and 61d of the circulation path forming member 61, and the other end portion is circulated. Each of the curved portions of the path forming member 62 is connected to a central portion in the circumferential direction.

  The shaft-like rolling element 50 is positioned closest to the bottom of the raceway groove 16 (upper side in FIG. 3) in the raceway recesses 17, 18 and the raceway recess 44, and the cage 60 is located with respect to the shaft-like rolling element 50. It is set so that a gap is provided between the retainer 60 and the groove bottom surface 161 of the track groove 16 in a state of being positioned closest to the groove bottom side of the track groove 16. This is the amount of axial movement of the track recesses 17 and 18 and the track recess 44 and the rolling surface portion 51, the amount of axial movement of the shaft-shaped rolling element 50 and the cage 60, and a pair of circulation path forming members of the cage 60. It is determined based on the axial thicknesses of 61 and 62 and the like.

  Furthermore, the opening of the raceway groove 16 is provided in the radially inner side of the outer ring 10 of the cage 60. In other words, the circulation path forming member 62 positioned radially inward of the cage 60 abuts on the axial rolling element 50 radially outward of the outer ring 10, but is not regulated inward of the outer ring 10 in the radial direction. Not.

  The operation of the constant velocity joint 1 described above will be described. When the outer ring 10 whose one end is connected to the differential gear is rotated by receiving power, the power is transmitted from the outer ring 10 to the shaft-shaped rolling element 50 fitted in the track recesses 17 and 18 of the track groove 16. Then, the power is transmitted from the shaft-shaped rolling element 50 to the outer power transmission surface 44a in contact with the shaft-shaped rolling element 50 that transmits power among the pair of split members 41 and 42. Power is transmitted to the tripod shaft portion 22 from the inner power transmission surface 43c of the split member 41 or 42 on the power transmission side.

  And the axial rolling element 50 is supported so that the outer periphery of the intermediate member 40 can circulate. Therefore, the shaft-shaped rolling element 50 is formed between the outer power transmission surface 44a of the raceway recess 44 of the split member on the power transmission side of the split members 41 and 42 and the bottom surface 17a and 18a of the raceway recesses 17 and 18. The power transmission surface 44a and the bottom surfaces 17a and 18a roll without sliding in the extending direction of the raceway groove 16 with respect to the power transmission surface 44a. Thereby, generation | occurrence | production of an induced thrust force can be suppressed.

  Further, the split member that receives power through the plurality of shaft-like rolling elements 50 among the pair of split members 41 and 42 transmits power to the tripod shaft portion 22 with which the inner power transmission surface 43c of the protrusion 43 abuts. . At this time, if the joint angle is added as described above, the tripod shaft portion 22 reciprocates (oscillates) in the rotation axis direction of the outer ring 10. At this time, the split members 41 and 42 in which the inner power transmission surface 43c of the protrusion 43 abuts the tripod shaft 22 follow the movement of the tripod shaft 22 in the radial direction of the outer ring 10, so that the shaft-like rolling element 50 slides in the radial direction of the outer ring 10 with respect to 50. As a result, the load point to which the most power is applied on the outer power transmission surface 44 a reciprocates in the axial direction of the axial rolling element 50.

  However, the pair of split members 41 and 42 are independent on the power transmission side and the back side thereof. Thereby, even if the load position by the tripod shaft part 22 which generate | occur | produces on the power transmission side changes, operation | movement of the division member by the side of power transmission among a pair of division members 41 and 42 changes to operation of the division member by the side of the back. There is no effect. Therefore, since the dividing members 41 and 42 located on the back side can be prevented from applying a large force to the raceway groove 16, the generation of the induced thrust force due to this can be suppressed.

  Further, according to the constant velocity joint 1 described above, the shaft-like rolling element 50 is fitted in the track recesses 17 and 18 and the track recess 44. As a result, when the axial rolling element 50 is caused to move in the axial direction due to the skew, the movement of the axial rolling element 50 is restricted by the track recesses 17 and 18 and the track recess 44. By the way, the cage 60 is disposed outside the track recesses 17 and 18 and the track recess 44. Therefore, only the track recesses 17 and 18 and the track recess 44 exhibit an effect of restricting the movement of the axial rolling element 50 due to skew, and the cage 60 is configured not to exhibit the effect of restricting the movement. That is, the movement of the cage 60 and the shaft-like rolling element 50 due to the skew is not restricted by the cage 60 itself contacting the outer ring 10.

  In particular, the shaft-shaped rolling element 50 is positioned closest to the groove bottom surface 161 of the track groove 16 in the track recesses 17, 18 and the track recess 44, and the cage 60 is the most of the track groove 16 with respect to the shaft-shaped rolling element 50. A gap is provided between the cage 60 and the groove bottom surface 161 of the raceway groove 16 in a state of being positioned on the groove bottom surface 161 side. Thereby, even if it is a case where skew arises, it can prevent that the holder | retainer 60 contacts the groove bottom face 161 of the raceway groove | channel 16 of the outer ring | wheel 10.

  Furthermore, the cage 60 is disposed with a gap with respect to the side surfaces 162 and 163 of the raceway groove 16. Thereby, it is possible to prevent the cage 60 from coming into contact with the side surfaces 162 and 163 of the raceway groove 16. In addition, an opening of the raceway groove 16 is located inward in the radial direction of the outer ring 10 of the cage 60. Therefore, even when the retainer 60 moves inward in the outer ring radial direction with respect to the outer ring 10, the retainer 60 can be prevented from coming into contact with the components of the outer ring 10.

  By these, it is possible to suppress the cage 60 from receiving a large load due to contact with the outer ring 10. As a result, it is not necessary to increase the bending rigidity of the cage 60, for example, to increase the plate thickness or to perform heat treatment. That is, the cost and weight of the cage 60 can be reduced.

  As described above, according to the constant velocity joint 1 of the present embodiment, the tripod shaft portion 22 has an axial cross section formed in a straight shape, and is provided on the outer periphery of the tripod shaft portion 22 so as to be swingable. On the inner peripheral surface of 40, a ridge portion 43 that protrudes inward in the radial direction of the tripod shaft portion 22 and extends in the circumferential direction is provided. That is, the constant velocity joint 1 of the present embodiment is different from the one having a structure in which the intermediate member is externally fitted in a spherical contact with the tripod shaft portion like a conventional needle circulation type constant velocity joint. .

  Thereby, when the tripod 20 is produced by forging, it is not necessary to form a convex spherical surface on the outer peripheral surface of the tripod shaft portion 22 as in the prior art, so that the die life is improved and the cost is reduced. it can. In particular, since the tripod shaft portion 22 is formed in a columnar shape, the shape of the tripod shaft portion 22 is simplified and necessary processing is suppressed to a minimum, so that the processing cost can be further reduced. Further, since it is not necessary to form a concave spherical surface on the inner peripheral surface of the intermediate member 40 as in the prior art, the shape of the intermediate member 40 can be simplified and the cost can be reduced.

  Further, in the present embodiment, the inner power transmission surface 43c of the protrusion 43 has a straight cross-sectional shape in a direction perpendicular to the axial direction of the tripod shaft 22, so that the intermediate member from the tripod shaft 22 is an intermediate member. When transmitting power to 40, the movement of the tripod shaft portion 22 that reciprocates (swings) in the direction of the outer ring rotation axis can be made smooth.

  Moreover, in this embodiment, the cross-sectional shape in the axial direction of the tripod shaft part 22 of the protruding tip surface 43a of the protrusion 43 is an arc shape that is convex in the protruding direction, and the axial cross-sectional shape is straight. It is comprised so that the protrusion front end surface 43a of the protrusion part 43 may contact the tripod shaft part 22 currently formed in the crossing state. Thereby, when transmitting motive power from the tripod shaft part 22 to the intermediate member 40, the movement of the tripod shaft part 22 which swings in the direction perpendicular to the outer ring rotation axis can be made smooth.

  Further, in the present embodiment, the radius of curvature R1 of the arc surface forming the inner power transmission surface 43c of the protruding tip surface 43a is larger than the radius of curvature R2 of the arc surface forming the protruding tip surface 43a other than the inner power transmission surface 43c. Since it is enlarged, the surface pressure of the inner side power transmission surface 43c of the protrusion 43 which contacts the tripod shaft part 22 can be reduced.

  And in this embodiment, the track | orbit recessed part 44 extended in the circumferential direction of the tripod shaft part 22 is formed in the surface facing the side surfaces 162 and 163 of the track groove 16 of the intermediate member 40. A portion of the rolling element 50 located on the intermediate member 40 side is fitted in the track recess 44 so as to be able to roll along the outer power transmission surface (bottom surface) 44 a of the track recess 44. Thereby, when the force which moves to the axial direction on the axial rolling element 50 by a skew generate | occur | produces, the said movement of the axial rolling element 50 can be controlled by the track | orbit recessed part 44. FIG.

  Further, in the present embodiment, since the protrusion 22a that prevents the intermediate member 40 from falling off is provided at the tip of the tripod shaft portion 22, the needle unit 30 (the intermediate member 40, It is possible to prevent the intermediate member 40 (needle unit 30) from dropping off from the tripod shaft portion 22 when the shaft-shaped rolling element 50 and the cage 60) are assembled. When the needle unit 30 is assembled, the retainer 60 is elastically deformed by pressing the needle unit 30 against the tripod shaft portion 22 so that the protrusion 43 of the intermediate member 40 gets over the protrusion 22a. .

  In the above embodiment, the radius of curvature R1 of the arc surface forming the inner power transmission surface 43c of the protruding tip surface 43a of the ridge 43 is an arc surface forming the protruding tip surface 43a other than the inner power transmission surface 43c. 9 and 10, as shown in FIGS. 9 and 10, the curvature radius R1 and the curvature radius R2 are the same in the entire circumferential direction of the tripod shaft portion 22 (for example, R2). ). If it does in this way, processing of intermediate member 40 will become easy and processing cost can be reduced further.

  Further, in the above-described embodiment, the shaft-like rolling element 50 is fitted into the track recesses 17 and 18 of the outer ring 10 and is fitted into the track recess 44 of the intermediate member 40. 17 and 18 may be excluded and only the track recess 44 of the intermediate member 40 may be provided. Thereby, processing cost can be reduced more.

  Further, in the above embodiment, the side surfaces 17b and 18b of the track recesses 17 and 18, the side surface 44b of the track recess 44, and the tapered end surface 51b of the shaft-like rolling element 50 are tapered, but are tapered. It is not limited.

  Moreover, in the said embodiment, although the tripod shaft part 22 is formed in the column shape, you may make it an elliptic cylinder shape. In this way, since the straight length L of the inner power transmission surface 43c provided in the protrusion 43 can be shortened, the intermediate member 40 can be reduced in size and weight.

  Moreover, in the said embodiment, although the intermediate member 40 is comprised by a pair of independent division members 41 and 42, it is also possible to make it the integral intermediate member 40. FIG. However, in this case, the above-described effects obtained by using the divided members 41 and 42 are not achieved.

1: constant velocity joint, 2: intermediate shaft 10: outer ring, 11: cylindrical part, 12: connecting shaft part 16: raceway groove, 161: groove bottom, 162, 163: side face 17, 18: raceway recess, 17a, 18a : Bottom surface, 17b, 18b: side surface 20: tripod 21: boss portion, 21a: internal spline 22: tripod shaft portion, 22a: protrusion 30: roller unit 40: intermediate member, 41, 42: divided member, 41a, 41b: Axial end surface 43: ridge portion, 43a: protruding tip surface, 43b: inclined surface, 43c: inner power transmission surface 44: raceway recess, 44a: outer power transmission surface (bottom surface), 44b: side surface 50: shaft-like rolling element 51: Rolling surface portion 51a: Rolling surface 51b: Tapered end surface 52: Projection portion 60: Retainer 61, 62: Circulation path forming members 61a, 61b: Straight portion, 61c, 61d Curved portion, 63 and 64: the connecting portion

Claims (8)

An outer ring having 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,
An intermediate member provided on the outer periphery of the tripod shaft portion so as to be swingable with respect to the tripod shaft portion, and having an outer power transmission surface facing the side surface of the raceway groove on the outer surface;
A plurality of axial rolling elements provided between the side surface of the raceway groove and the outer power transmission surface so as to roll along the side surface of the raceway groove;
A cage that supports the shaft-like rolling element so that the shaft-like rolling element can circulate around the outer periphery of the intermediate member;
With
The cross-sectional shape in the axial direction of the tripod shaft portion of the outer peripheral surface of the tripod shaft portion is formed in a straight shape,
On the inner peripheral surface of the intermediate member, a protruding portion that protrudes inward in the radial direction of the tripod shaft and extends in the circumferential direction is provided .
The inner power transmission surface that transmits power by contacting the tripod shaft portion of the ridge portion has a straight cross-sectional shape in a direction orthogonal to the axial direction of the tripod shaft portion. Sliding tripod type constant velocity joint. Oite to claim 1,
A sliding tripod constant velocity joint characterized in that a cross-sectional shape in the axial direction of the tripod shaft portion of the protruding tip surface of the ridge portion is an arc shape convex in the protruding direction. In claim 2 ,
A sliding tripod type constant velocity joint characterized in that the arcuate cross-sectional shape of the protruding tip surface is the same in the entire circumferential direction of the tripod shaft portion. In claim 2 ,
The radius of curvature of the arc surface forming the inner power transmission surface of the protruding tip surface is larger than the radius of curvature of the arc surface forming the protruding tip surface other than the inner power transmission surface. Sliding tripod type constant velocity joint. In any one of Claims 1-4 ,
A track recess that extends in the extending direction of the track groove is formed on a surface of the intermediate member that faces the side surface of the track groove.
The shaft-shaped rolling element is provided such that a portion of the shaft-shaped rolling element located on the intermediate member side is fitted into the track recess so as to roll along the bottom surface of the track recess. Sliding tripod type constant velocity joint. In any one of Claims 1-5 ,
The said intermediate member is comprised by a pair of division member arrange | positioned in the separated state so that the said tripod shaft part may be pinched | interposed from the both sides of the side surface of the said track groove, The sliding type tripod type constant velocity joint characterized by the above-mentioned. In any one of Claims 1-6 ,
The tripod shaft constant velocity joint is characterized in that the tripod shaft portion is formed in a cylindrical shape. In any one of claim 1 to 7
A sliding tripod type constant velocity joint, characterized in that a protrusion for preventing the intermediate member from falling off is provided at the tip of the tripod shaft.

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