JP2006046464A - Tripod type constant speed universal joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tripod type constant speed universal joint whose external joint member is reduced in weight while preserving boots holding force. <P>SOLUTION: A bottom 15 of each track groove 13 formed in an inner circumferential surface of the external joint member 10 is formed in a flat-surface shape and is arranged in close proximity to a roller end face 39. Among outer circumferential portions, in portions where the track grooves 13 are formed and in portions corresponding to portions between the track grooves, there are provided a first thinned portion 16 and a second thinned portion 17 which are formed in a depressed canaliform shape. While ensuring fully circumferential lengths of a maximum turning radius portion 11a of the external joint member 10 and maximum internal diametrical portion 43a of the boots 40 corresponding to the maximum turning radius portion 11a, a weight of the external joint member 10 is reduced. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a tripod type constant velocity universal joint that is incorporated in, for example, a driving system of an automobile and used to transmit rotational force between rotating shafts that are mainly non-linear.

  9 and 10 show an example of a conventional tripod type constant velocity universal joint. As shown in FIGS. 9 and 10, this tripod type constant velocity universal joint has three track grooves 51 extending in the axial direction on the inner peripheral surface, and a pair of roller guide surfaces on both sides in the circumferential direction of each track groove 51. 52, an inner joint member 55 in which three leg shafts 54 are extended in the radial direction, and a leg shaft 54 that is swingably fitted over the roller guide surface 52. A roller 56 that is movably inserted, and that allows torque transmission between the members 53 and 55 while allowing angular displacement and axial displacement of the outer joint member 53 and the inner joint member 55. It is.

  This kind of tripod type constant velocity universal joint is usually filled with a lubricant in order to reduce the frictional force inside the joint, but the lubricant leaks to the outside of the joint or foreign matter enters the inside of the joint. If it enters, poor lubrication occurs. In order to prevent such poor lubrication, a boot 57 for sealing the inside of the joint is attached to the tripod type constant velocity universal joint.

  Further, tripod type constant velocity universal joints are frequently used in automobile drive systems and the like, and weight reduction is demanded from the viewpoint of improving fuel efficiency and speeding up of automobiles. Conventionally, as shown in FIG. 10, in the outer peripheral portion of the outer joint member 53, a portion having a diameter smaller than the maximum rotation diameter R of the outer joint member 53 is formed in a portion corresponding to the portion between the formation positions of the track grooves 51. The tripod type constant velocity universal joint is provided by forming the thinned portion 58 of one and forming the track groove bottom portion 59 into a concave curved surface having a substantially arcuate cross section corresponding to the outer peripheral shape of the outer joint member 53 to be thin. The weight is reduced.

  On the other hand, in the tripod type constant velocity universal joint shown in FIG. 11, the track groove bottom portion 59 is formed in a flat surface shape and is disposed close to the end surface of the roller 56, and the track groove 51 is formed in the outer peripheral portion of the outer joint member 53. A second thinning portion 60 having a diameter smaller than the maximum rotation diameter R of the outer joint member 53 is provided at a portion corresponding to the location. The second thinned portion 60 is formed in a flat surface substantially parallel to the track groove bottom 59 (see, for example, Patent Document 1). The maximum rotation diameter R of the outer joint member 53 is the outer diameter of the portion corresponding to the vicinity of both ends of the track groove 51 in the outer peripheral portion of the outer joint member 53.

  In the tripod type constant velocity universal joint of FIG. 11, the track groove 51 of the outer joint member 53 is formed in a flat plate shape. On the other hand, in the tripod type constant velocity universal joint shown in FIGS. 9 and 10, the track groove 51 of the outer joint member 53 is formed in a partially cylindrical shape. Therefore, the tripod type constant velocity universal joint shown in FIG. 11 has a circumferential length at the location where the track groove 51 is formed if the width of the track groove 51 is the same as that of the tripod type constant velocity universal joint shown in FIGS. Becomes shorter. Further, if the thickness at the formation location of the track groove 51 is the same, it is lighter than the tripod type constant velocity universal joint shown in FIGS. 9 and 10 because the circumferential length at the formation location of the track groove 51 is shorter. Become.

JP 2003-202034 A

  However, the tripod type constant velocity universal joint shown in FIG. 11 forms a portion of the outer peripheral portion of the outer joint member 53 corresponding to the formation location of the track groove 51 in a flat surface shape substantially parallel to the track groove bottom 59. Therefore, the circumferential length of the maximum rotational diameter portion of the outer joint member 53 is shortened. The mechanism for preventing the axial displacement of the fitting portion between the outer joint member 53 and the boot 57 is a short maximum rotational diameter portion in the circumferential direction of the outer joint member 53, assuming a machining process considering low cost. Therefore, the holding force in the axial direction cannot be increased, and not only the boot 57 is easily detached from the outer joint member 53, but also the sealing performance is deteriorated and the lubricant may be leaked.

  The present invention was devised in view of such circumstances, and an object of the present invention is to provide a tripod type constant velocity universal joint that reduces the weight of the outer joint member while ensuring the holding force of the boot. is there.

  In order to achieve the above object, the present invention has an outer joint member having three track grooves extending in the axial direction on the inner peripheral surface, and a pair of roller guide surfaces formed on both sides in the circumferential direction of each track groove, and a radius. An inner joint member having three leg shafts extending in the direction, a roller fitted to the leg shaft so as to swing freely, and inserted between the roller guide surfaces of the outer joint member so as to roll freely, and one end A track groove bottom formed in a flat surface shape, including a boot that fits to the outer periphery of the outer joint member and fits the other end to a shaft extending from the inner joint member to seal the inside of the joint Is disposed close to the end face of the roller, and a first thinning portion is provided in a portion corresponding to the space between the formation positions of the track groove in the outer peripheral portion of the outer joint member, and among the outer peripheral portion of the outer joint member. Tripod type with a second thinning part in the part corresponding to the track groove formation location In the constant velocity universal joint is characterized in that formed in the concave groove shape extending a second reduced thickness portion in the axial direction of the outer joint member.

  In the above tripod type constant velocity universal joint, the second thinning portion is formed in a concave groove shape such as an inverted U-shaped cross section or a concave curved cross section. If the amount of thinning is the same as in the case of the conventional example in which the portion corresponding to the groove formation portion is thinned to a flat surface, the circumferential length of the maximum rotational diameter portion of the outer joint member is longer than in the conventional example. Become. The thinning amount here is a space volume surrounded by a cylinder having a radius of the maximum rotation diameter of the outer joint member and the second thinning portion. As described above, when the circumferential length of the maximum rotational diameter portion of the outer joint member is increased, the boot fitted to the outer joint member is formed with a longer circumferential length of the maximum inner diameter portion. The circumferential length of the mechanism that prevents axial displacement of the fitting portion between the joint member and the boot is also increased. Therefore, the holding force of the boot is improved, and the sealing performance between the outer joint member and the boot is also improved.

  As described above, the tripod type constant velocity universal joint according to the present invention forms the track groove bottom portion of the outer joint member in a flat surface shape and is disposed close to the roller end surface, and the track groove in the outer peripheral portion of the outer joint member. Since the groove-shaped second thinned portion is provided in the portion corresponding to the formation location, the tripod constant velocity universal joint can be reduced in weight while ensuring the holding force of the boot.

  The best mode for carrying out the present invention will be described below with reference to the drawings. FIG. 1 is an axial sectional view showing a first embodiment of a tripod type constant velocity universal joint according to the present invention, and FIG. 2 is an enlarged sectional view of an essential part in the direction orthogonal to the axis.

  In FIG. 1, reference numeral 10 denotes an outer joint member, which is connected to a bottomed cylindrical mouse portion 11 having one end opened and one of two shafts (not shown) to be coupled so as to transmit torque. Stem portion 12. As shown in FIG. 2, three track grooves 13 extending in the axial direction are formed on the inner circumferential surface of the mouse portion 11 at each of the circumferentially divided positions. A pair of roller guide surfaces 14 are disposed opposite to each other in the circumferential direction of each track groove 13. Each roller guide surface 14 is a concave curved surface having a substantially arc-shaped cross section. The track groove bottom portion 15 is formed in a flat surface shape that connects the radially outer ends of the pair of roller guide surfaces 14. A first thinned portion 16 having a smaller diameter than the maximum rotation diameter R of the outer joint member 10 is provided in a portion corresponding to the space between the formation positions of the track grooves 13 in the outer peripheral portion of the outer joint member 10. is there. The first thinned portion 16 is a groove having a concave curved surface extending in the axial direction of the outer joint member 10, and is formed at a circumferentially divided position of the outer peripheral portion of the outer joint member 10. In addition, a second thinned portion 17 having a diameter smaller than the maximum rotation diameter R of the outer joint member 10 is provided in a portion corresponding to the formation location of the track groove 13 in the outer peripheral portion of the outer joint member 10. . The second thinned portion 17 is formed so that the cross-sectional shape of the outer joint member 10 in the direction orthogonal to the axis is substantially the same as that of the first thinned portion 16. Further, the second thinning portion 17 is formed at the central portion between the first thinning portions 16. That is, the outer joint member 10 according to the first embodiment is provided with the first and second thinned portions 16 and 17 in the shape of concave grooves extending in the axial direction alternately at the circumferentially equally divided position of the outer peripheral portion. It is intended to reduce weight.

  In each figure, reference numeral 20 denotes an inner joint member, which includes a boss portion 21 formed in an annular shape, and a leg shaft 22 protruding in a radial direction from each of the three circumferential positions of the outer peripheral surface of the boss portion 21. The other shaft S of the two shafts to be connected to the serration hole 23 of the boss portion 21 is fitted so that torque can be transmitted. The leg shaft 22 is formed so as to extend into the track groove 13 when the inner joint member 20 is inserted into the outer joint member 10. A spherical portion 24 formed in a substantially convex spherical shape in the radial direction of the leg shaft 22 is provided on the outer periphery of the distal end portion of the leg shaft 22.

  In each figure, reference numeral 30 denotes a roller, which is fitted on the leg shaft 22 so as to be swingable, and is inserted between the roller guide surfaces 14 of the outer joint member 10 so as to be able to roll. This roller 30 is of a double roller type having two rollers, an inner roller 31 and an outer roller 32.

  The inner roller 31 is an annular member having a substantially concave spherical inner peripheral surface 33. The inner roller inner peripheral surface 33 has a generatrix curvature radius substantially the same as the generatrix curvature radius of the spherical portion 24 so that when the roller 30 is attached to the leg shaft 22, it is spherically fitted to the spherical portion 24 of the leg shaft 22. Yes. As a result, the inner roller 31 is swingable with respect to the leg shaft 22.

  The outer roller 32 is an annular member having an outer peripheral surface 34 having a convex arc shape in cross section. The outer peripheral surface 34 of the outer roller has a generatrix radius of curvature substantially the same as that of the roller guide surface 14 so as to make a solid contact with the roller guide surface 14 in a torque load state.

  A plurality of needle rollers 37 are interposed between the cylindrical outer peripheral surface 35 of the inner roller 31 and the cylindrical inner peripheral surface 36 of the outer roller 32. Specifically, a retainer 38 is provided over the entire circumference of both edges of the cylindrical inner peripheral surface 36 of the outer roller 32, and a plurality of needle rollers 37 are movable between the retainers 38 in a slight axial direction and are rotatable. Is housed in. Thereby, the inner roller 31 and the outer roller 32 can be relatively rotated and relatively moved in the leg axis direction.

  In each figure, reference numeral 40 denotes a boot, one end of which is fitted to the mouth portion 11 of the outer joint member 10 and the other end is fitted to a shaft S extending from the inner joint member 20, It is to be sealed. The boot 40 is formed of an elastic material such as rubber or synthetic resin in a bellows shape, and both ends are fastened and fixed by boot bands 41 and 42. The fitting portion 43 of the boot 40 with respect to the outer joint member 10 has an inner peripheral shape substantially the same as the outer peripheral shape of the outer joint member 10.

  In the tripod constant velocity universal joint according to the first embodiment, as described above, the track groove bottom portion 15 is formed in a flat surface shape that connects the radially outer ends of the pair of roller guide surfaces 14 and the roller guide surface 14. Since it is disposed close to the end surface 39 of the outer roller 32 accommodated therebetween, the difference in diameter between the inner diameter at the center of the track groove bottom portion 15 and the maximum rotation diameter R of the outer joint member 10 is determined at both ends of the track groove bottom portion 15. This is larger than the diameter difference between the inner diameter of the portion and the maximum rotation diameter R of the outer joint member 10. As a result, a space is provided in the outer peripheral portion of the outer joint member 10 where the groove-shaped second thinned portion 17 is provided in a portion corresponding to the location where the track groove 13 is formed, thereby reducing the weight of the outer joint member 10. Can be achieved.

  Further, by forming the first thinned portion 16 and the second thinned portion 17 in the shape of a concave groove, the circumferential length of the maximum rotation diameter portion 11a of the outer joint member 10 is secured sufficiently long. The desired amount of thinning is maintained. The mechanism for preventing the axial displacement of the fitting portion between the outer joint member 10 and the boot 40 can be set only at the maximum rotational diameter portion of the outer joint member 10 on the premise of a machining process considering low cost. However, since the circumferential length of the maximum rotation diameter portion can be sufficiently long, the holding force of the boot 40 is improved.

  In addition, by providing the first thinned portion 16 and the second thinned portion 17 alternately at six equal positions in the circumferential direction of the outer peripheral portion of the outer joint member 10, the outer joint member 10 has symmetry. As a result, the rotation of the tripod type constant velocity universal joint is stabilized.

  Furthermore, by forming the cross-sectional shape of the first thinned portion 16 and the cross-sectional shape of the second thinned portion in the direction orthogonal to the axis of the outer joint member 10 into substantially the same shape, the outer joint member 10 has a boot. The working efficiency when fitting 40 is improved. Specifically, the boot 40 can be fitted to the outer joint member 10 by simply aligning one of the maximum rotational diameter portions 11a of the outer joint member 10 and one of the maximum inner diameter portions 43a of the boot 40. Mistakes can be prevented.

  On the other hand, the tripod type constant velocity universal joint has an angular displacement θ in a state where the operating angle θ is taken, that is, in the axial direction of the outer joint member 10 and the axial direction of the inner joint member 20 as shown in FIG. When torque is applied in a state where the inner joint member 20 is attached, each leg shaft 22 swings along the corresponding track groove 13 as indicated by an arrow a in accordance with the rotation of the inner joint member 20. At this time, the outer roller 32 is pressed against the roller guide surface 14 on the load side by the leg shaft 22 and reciprocates along the track groove 13 while rolling on the roller guide surface 14 on the load side.

When the leg shaft 22 swings along the track groove 13, the inner roller 31 swings with respect to the leg shaft 22, so that a frictional force is generated between the inner shaft 31 and the leg shaft 22. This frictional force is transmitted to the outer roller 32 via the inner roller 31, and a spin moment M ₁ that changes the inclination φ _{1 (} ω _t) of the outer roller 32 within the axial cross section of the outer joint member 10 is generated.

Further, when the leg shaft 22 swings along the track groove 13, the tip position of the leg shaft 22 is displaced in the radial direction of the outer joint member 10. At this time, as shown in FIG. 4, the action line of the force F ₂ applied from the leg shaft 22 to the inner roller 31 with respect to the action line of the force F ₁ applied from the roller guide surface 14 on the load side to the outer roller 32. Is offset, and a spin moment M ₂ is generated that changes the inclination φ _{2 (} ω _t) of the outer roller 32 within the cross section of the outer joint member 10 in the direction orthogonal to the axis.

Usually, the above-mentioned spin moments M ₁ and M ₂ are generated simultaneously, and the inclinations φ _{1 (} ω _t) and φ _{2 (} ω _t) in each direction of the outer roller 32 depend on the use conditions and the rotational phase angle of the inner joint member 20. It will change from moment to moment. However, in the case of an application that transmits a relatively large torque, such as a driving system of an automobile, the inclination of the outer roller 32 is increased by the spin moments M ₁ and M ₂ . When the inclination of the outer roller 32 increases, the outer roller 32 and the non-load-side roller guide surface 14 come into contact with each other, and the rolling resistance of the outer roller 32 increases. As a result, an excessive frictional force is generated inside the joint, and the rotational tertiary axial force is increased. This axial force becomes a factor that generates vibration called shudder in an automobile or the like incorporating a tripod type constant velocity universal joint.

  In the tripod type constant velocity universal joint described above, the track groove bottom portion 15 is formed in a flat surface shape connecting the end portions of the pair of roller guide surfaces 14, and is formed on the end surface 39 of the outer roller 32 accommodated between the roller guide surfaces 14. Since they are arranged close to each other, even if the outer roller 32 tilts with respect to the track groove bottom 15 in a torque load state, the outer roller end surface 39 is supported by the track groove bottom 15 and the inclination of the outer roller 32 with respect to the track groove bottom 15 is restricted. The Accordingly, contact between the outer roller 32 and the non-load-side roller guide surface 14 is avoided, and the rolling resistance of the outer roller 32 can be suppressed. As a result, the frictional force inside the joint is suppressed, and the rotational tertiary axial force can be reduced.

  Next, a second embodiment of the tripod constant velocity universal joint according to the present invention will be described with reference to FIGS. 5 and 6. As shown in FIG. 5, the tripod type constant velocity universal joint in the second embodiment is provided with a relief portion 25 formed in the torque load region of the leg shaft 22 of the inner joint member 20 so as to be smaller in diameter than the spherical inner diameter of the inner roller 31. This is different from the tripod type constant velocity universal joint in the first embodiment. Since the other points are the same as those in the first embodiment, the difference will be mainly described below.

  As shown in FIG. 5, the escape portion 25 is a portion where the torque load region of the leg shaft 22 of the inner joint member 20 is partially formed with a smaller diameter than the inner roller inner peripheral surface 33. The torque load region in the present embodiment is the spherical portion 24. The spherical portion 24 is a portion that is spherically fitted to the inner roller inner peripheral surface 33, but by providing the relief portion 25 partially, an effect of reducing interference when assembling the inner roller 31 to the leg shaft 22 is obtained. The amount of elastic deformation of the inner roller 31 can be reduced or zero.

  Further, as shown in FIG. 6, the relief portion 25 is provided in a region including the protrusion 26 formed on the forged parting line of the spherical portion 24. Thus, when the escape portion 25 is provided along the forging parting line of the spherical portion 24, the protrusion 26 protrudes from a position retracted inward from the inner roller inner peripheral surface 33. If the ridge 26 is formed so as not to protrude from the inner roller inner peripheral surface 33, the step of removing the ridge 26 can be omitted, and the cold formed surface can be used, and the cost can be reduced.

Various specific modes of the escape portion 25 are conceivable, but as a most preferable mode, as shown in FIG. 6, the cross-sectional shape in the direction orthogonal to the leg axis is a substantially dihedral shape. Specifically, when the radius of curvature of the inner roller in the peripheral surface 33 and an R _0, sets two spherical radius r ₀ of the relief portion 25 in the range of _{R 0/2 <r 0 <} R 0. In this case, the contact between the spherical portion 24 and the inner roller 31 is located at two symmetrical positions with the forging parting line of the leg shaft 22 in between. When the spherical portion 24 and / or the inner roller 31 are elastically deformed in the torque load state, the contact region (substantially elliptical region) between the spherical portion 24 and the inner roller 31 moves continuously along the escape portion 25. For this reason, stress concentration does not occur at the edge of the relief portion 25, and the durability of the leg shaft 22 can be improved.

On the other hand, when the escape portion 25 is provided in the spherical portion 24, the spherical portion 24 and the inner roller 31 come into contact with each other at two symmetrical positions sandwiching the protrusion 26, so that it occurs between the spherical portion 24 and the inner roller 31. Frictional force increases. As the frictional force increases, the spin moment M ₁ for tilting the roller 30 increases. Even if the spin moment M ₁ is increased, the inclination of the roller 30 with respect to the track groove bottom 15 is maintained substantially constant regardless of the rotational phase angle of the inner joint member 20, so that the frictional force generated inside the joint is stabilized. Further, it is possible to prevent an excessive frictional force from being generated inside the joint due to the rotational phase angle of the inner joint member 20.

Next, a third embodiment of the tripod type constant velocity universal joint according to the present invention will be described with reference to FIG. Tripod type constant velocity universal joint in the third embodiment, as shown in FIG. 7, a gap [delta] ₁ [mm] between the outer roller outer peripheral surface 34 and the roller guide surface 14 formed in the torque load conditions, [delta] ₁ > 0.03 / A, and the gap δ ₂ [mm] between the outer roller end face 39 and the track groove bottom 15 is set to δ ₂ > 0.15 × A. However, A = r ₁ / R ₁ (where r ₁ is the radius of curvature of the bus bar of the outer peripheral surface 34 of the outer roller and R ₁ is the outer radius of the outer roller 32). In the third embodiment, the case where the gaps δ ₁ and δ ₂ are applied to the tripod type constant velocity universal joint in the first embodiment will be described. However, the tripod type constant velocity universal joint in the second embodiment is used. Of course, it is applicable.

The tripod type constant velocity universal joint according to the third embodiment has a circularity A (= r ₁ / R ₁ ) expressed by a ratio of a bus-bar curvature radius r _{1 to} an outer diameter radius R ₁ of the outer roller 32, and a track groove 13. Focusing on the relationship with the outer roller 32 inclined in various directions, the gap δ ₁ between the outer roller outer peripheral surface 34 and the non-load-side roller guide surface 14, and between the outer roller end surface 39 and the track groove bottom 15 The gap δ ₂ is determined. That is, the smaller the value of the circularity A, the more easily the outer roller 32 is inclined in the cross section perpendicular to the axis of the outer joint member 10, and the outer roller outer peripheral surface 34 and the unloaded roller guide surface 14 are in contact with each other. On the other hand, in the cross section including the axis of the outer joint member 10, a recovery couple M ₃ (see FIG. 3) that opposes the spin moment M ₁ is likely to occur, and the outer roller end surface 39 and the track groove bottom 15 Becomes difficult to touch. Conversely, the greater the degree of circularity A, the easier it is to tilt within the cross section including the axis of the outer joint member 10, and the outer roller end surface 39 and the track groove bottom 15 are more likely to come into contact. In the cross section perpendicular to the axis, the inclination due to the spin moment M ₂ hardly occurs, and the outer roller outer peripheral surface 34 and the non-load-side roller guide surface 14 are difficult to contact.

Based on the above examination results, in this embodiment, the clearance δ ₁ between the outer roller outer circumferential surface 34 formed in the torque load state and the non-load-side roller guide surface 14 is set to δ ₁ > 0.03 / A. As a setting, an inversely proportional relationship was given between the gap δ ₁ and the circularity A. As a result, even when the circularity A of the outer roller 32 is different, the contact between the outer roller outer circumferential surface 34 and the non-load-side roller guide surface 14 is avoided as much as possible, or becomes zero, so that the frictional force inside the joint is suppressed. .

In this embodiment, the gap δ ₂ between the outer roller end surface 39 and the track groove bottom 15 is set to δ ₂ > 0.15 × A, so that the gap δ ₂ and the circularity A are between Proportional relationship was given. Thereby, even when the circularity A of the outer roller 32 is different, the contact force between the outer roller end surface 39 and the track groove bottom 15 is reduced, so that the frictional force inside the joint is suppressed.

As described above, when the gaps δ ₁ and δ ₂ are appropriately set according to the circularity A of the outer roller 32, the rotational tertiary axial force can be further reduced, and the effect of suppressing the shudder and the rotation durability can be further increased. Can be improved. The value of the circularity A of the outer roller 32 is preferably set within the range of 0.475 ≦ A <1.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be made. For example, in the said embodiment, although the cross-sectional shape of the 1st thinning part 16 and the 2nd thinning part 17 is formed substantially the same, these cross-sectional shapes may differ. Specifically, as shown in FIG. 8A, the width of the second thinned portion 17 is made narrower than that of the first thinned portion 16, or the groove depth of the second thinned portion 17 is increased. It is also possible to make it shallower than the first thinned portion 16. However, in this case, the work efficiency of attaching the boot 40 to the outer joint member 10 may be reduced. Further, as shown in FIG. 8B, the second thinned portion 17 can be formed in a groove shape other than a groove having a concave curved surface, such as a groove having an inverted U-shaped cross section. It is. In this case, it is possible to reduce the weight of the tripod type constant velocity universal joint while securing the holding force of the boot 40. However, when the boot 40 is fitted to the outer joint member 10, the outer joint member 10 and the boot There is a possibility that a gap is easily formed between the joints 40 and the sealing performance of the joint is lowered.

  Further, in the above-described embodiment, the bus guide radius of the roller guide surface 14 and the bus bar curvature radius of the outer roller outer peripheral surface 34 are made substantially the same, and both are made to make a solid contact, but the roller guide surface 14 has a Gothic arch shape, The surface 34 and the roller guide surface 14 may be in angular contact.

  In the above-described embodiment, the retainer 38 that holds the needle rollers 37 is formed integrally with the outer roller 32. However, the retainer 38 that is formed separately from the outer roller 32 may be fixed to the outer roller 32. Absent. Further, the retainer 38 may be provided not on the outer roller 32 but on the inner roller 31.

It is an axial direction sectional view shown in a 1st embodiment of a tripod type constant velocity universal joint concerning the present invention, and shows the state where the axial direction of an outer joint member and an inner joint member was made to correspond. It is an axial orthogonal direction sectional view shown in a 1st embodiment of a tripod type constant velocity universal joint concerning the present invention, and shows the state where the axial direction of an outer joint member and an inner joint member was made to correspond. It is principal part sectional drawing shown in 1st Embodiment of the tripod type | mold constant velocity universal joint which concerns on this invention, Comprising: The state which took the operating angle (theta) and applied the torque to the outer joint member and the inner joint member Show. FIG. 3 is an enlarged cross-sectional view of the main part of the tripod type constant velocity universal joint according to the present invention in the direction orthogonal to the axis shown in the first embodiment, and the torque is applied to the outer joint member and the inner joint member by taking the operating angle θ. Indicates the state. It is a principal part expanded sectional view which shows 2nd Embodiment of the tripod type | mold constant velocity universal joint which concerns on this invention. It is a principal part expanded sectional view in the WW line of FIG. It is a principal part expanded sectional view of the direction orthogonal to an axis which shows a 3rd embodiment of a tripod type constant velocity universal joint concerning the present invention. (A) A figure and (B) figure are principal part expanded sectional views of the direction orthogonal to an axis which shows other embodiments of a tripod type constant velocity universal joint concerning the present invention. It is sectional drawing of the axial direction which shows an example of the conventional tripod type constant velocity universal joint, Comprising: It shows the state which took the operating angle (theta) and applied the torque to the two shafts which should be connected. It is sectional drawing of the axis line orthogonal direction of the conventional tripod type constant velocity universal joint, Comprising: The state which made the axial direction of two axes correspond is shown. It is sectional drawing of the orthogonal direction of an axis which shows the other example of the conventional tripod type constant velocity universal joint.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Outer joint member 13 Track groove 14 Roller guide surface 15 Track groove bottom part 16 First thinning part 17 Second thinning part 20 Inner joint member 22 Leg shaft 24 Spherical part 25 Escape part 26 Projection line 30 Roller 31 Inner roller 32 Outer roller 33 Inner roller inner peripheral surface 34 Outer roller outer peripheral surface 39 Outer roller end surface 40 Boot 43 Fitting portion 43a Maximum inner diameter portion

Claims (9)

  An outer joint member having three track grooves extending in the axial direction on the inner peripheral surface, and a pair of roller guide surfaces formed on both sides in the circumferential direction of each track groove, and three leg shafts extending in the radial direction An inner joint member, a roller that is rotatably fitted to the leg shaft and can be moved in the axial direction of the leg shaft, and is rotatably inserted between the roller guide surfaces of the outer joint member, and one end of the outer joint member And a boot that fits to the outer periphery of the member and fits the other end to a shaft extending from the inner joint member and seals the inside of the joint. A first thinning portion is provided in a portion corresponding to the space between the formation positions of the track groove in the outer peripheral portion of the outer joint member, and is disposed in the vicinity of the end surface. Tripod type constant velocity with a second thinning part in the part corresponding to the formation location In the hand, the tripod type constant velocity joint being characterized in that formed in the concave groove shape extending a second reduced thickness portion in the axial direction of the outer joint member.   The tripod type constant velocity universal joint according to claim 1, wherein the first thinned portion and the second thinned portion are provided at six circumferential positions of the outer peripheral portion of the outer joint member.   The tripod type constant velocity according to claim 2, wherein the cross-sectional shape of the first thinned portion and the cut shape of the second thinned portion in the direction orthogonal to the axis of the outer joint member are formed in substantially the same shape. Universal joint.   The roller is fitted on the inner joint member's leg shaft so as to be swingable, and the inner roller is fitted on the inner roller so as to be capable of relative rotation and axial movement. And an outer roller that is movably inserted. The end surface of the outer roller that tilts with respect to the track groove bottom in a torque load state is supported by the track groove bottom, and the tilt of the outer roller with respect to the track groove bottom is regulated. Item 3. A tripod type constant velocity universal joint according to item 1.   In the case where the inner roller is spherically fitted to the leg shaft of the inner joint member, a relief portion formed with a smaller diameter than the inner peripheral surface of the inner roller is provided in the torque load region of the leg shaft of the inner joint member. The tripod type constant velocity universal joint according to claim 4.   6. The tripod type constant velocity universal joint according to claim 5, wherein a relief portion is provided in a region including a protrusion formed on a forged parting line of a leg shaft of the inner joint member.   The tripod constant velocity universal joint according to claim 5 or 6, wherein a cross-sectional shape of the relief portion in a direction orthogonal to the axis of the leg shaft is formed in a substantially dihedral shape. The tripod type or the like according to claim 4, wherein a gap δ1 [mm] between the outer peripheral surface of the outer roller formed in a torque load state and the roller guide surface is set to δ1> 0.03 / A. Fast universal joint:
However, A = r1 / R1 (r1 is the radius of curvature of the outer peripheral surface of the outer roller and R1 is the outer radius of the outer roller). The tripod type constant velocity universal joint according to claim 4, wherein the gap δ2 [mm] between the end face of the outer roller and the track groove bottom is set to δ2> 0.15 x A.
However, A = r1 / R1 (r1 is the radius of curvature of the outer peripheral surface of the outer roller and R1 is the outer radius of the outer roller).

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