JPH11336784A - Universal uniform coupling - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve lubricating performance of a sliding surface of a shaft part and a torque transmission member. SOLUTION: A curvature radius corresponding to circular arc parts 16A-16D and a curvature radius corresponding to an inner peripheral surface of an inner roller 8 are set in different values in a universal uniform coupling having a cylindrical outer race and a shaft arranged inside of the outer race, furnished with a plural number of grooves formed on an inner periphery of the outer race, plural trunnions 15 formed on an outer periphery of the shaft and a ring roller assembly body 17 respectively installed on an outer periphery of each of the trunnions 15 and free to move in the longitudinal direction of each of the grooves, constituted so that a plural number of the trunnions and each of the roller assembly bodies 17 are free to relatively move in a height direction of each of the trunnions 15 and having circular arc parts 16A-16D formed on an outer peripheral surface 16 of each of the trunnions 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a constant velocity universal joint arranged on a torque transmission path of a vehicle.

[0002]

2. Description of the Related Art Generally, when two members are arranged in a torque transmission path of a vehicle, and the two members are connected with a predetermined operating angle, the two members are connected by a constant velocity universal joint. Sometimes. This constant velocity universal joint includes a Zeppa type joint, a tripod type joint, a cross groove type joint, and a double offset type joint. A tripod joint is used at a portion where the amount of movement between two members in the axial direction is large, such as a differential side of a front drive shaft of a vehicle or a differential side of a rear drive shaft. One example of such a tripod joint is described in JP-A-7-103251 and JP-A-9-310723.

The tripod type joint described in these publications has a tubular outer member rotatable about a first axis, a tubular outer member disposed inside the outer member, and a predetermined axis relative to the first axis. An inner member rotatable about a second axis intersecting at an angle. In addition, three grooves extending in the first axis direction are formed at regular intervals on the inner periphery of the outer member in the circumferential direction. Further, three shaft portions are formed from the outer periphery of the inner member toward the three grooves. An annular torque transmitting member that is movable in the longitudinal direction of each groove is attached to the outer periphery of each shaft. The torque transmission member includes an inner roller that contacts the outer periphery of the shaft, an outer roller that contacts the groove of the outer member, and a plurality of needles disposed between the inner roller and the outer roller.

In the above-mentioned tripod type joint, for example, the torque of the outer member is transmitted to the inner member via the torque transmitting member. Here, in the tripod joint, the first axis of the outer member and the second axis of the inner member are used.
In order to rotate in a state where the axis and the axis intersect at a predetermined angle, with the change of the rotation phase of the outer member and the inner member, each torque transmitting member and each shaft portion relatively move in the longitudinal direction of the shaft portion,
In addition, the torque transmitting member swings with respect to the shaft.
Further, each torque transmitting member moves in the length direction of each groove. The above operation maintains the constant speed rotation of the inner member and the outer member.

On the other hand, grease is sealed inside the outer member, and the sliding surface between the groove of the outer member and the torque transmitting member, and the sliding surface between each torque transmitting member and each shaft portion are made of grease. Lubricated.

[0006]

In the tripod joint described in the above publication, an arc-shaped portion is formed on the inner peripheral surface of the inner roller of the torque transmitting member. Further, an arc-shaped portion is formed on the outer peripheral surface of the shaft portion. The transmission of torque is performed via a contact point between the two arc-shaped portions.

Here, the center of curvature of the arc-shaped portion of the inner roller and the center of curvature of the arc-shaped portion of the shaft are set at the same position. That is, the radius of the arc-shaped portion of the inner roller and the radius of the arc-shaped portion of the shaft portion are set to be the same. For this reason, the arc-shaped portion of the inner roller and the arc-shaped portion of the shaft portion are in line contact over the entire area in the circumferential direction. Therefore, it is difficult for grease to intervene between the sliding surfaces of the arc-shaped portion of the inner roller and the arc-shaped portion of the shaft portion, and the frictional resistance of the sliding region between the two arc-shaped portions increases. As a result, heat, abrasion, flaking, adhesion and the like of the inner roller and the shaft portion may occur, and the durability of the tripod type joint may be reduced.

The present invention has been made in view of the above circumstances, and has as its object to provide a constant velocity universal joint capable of improving lubrication performance on a sliding surface between a shaft portion and a torque transmitting member.

[0009]

In order to achieve the above object, the present invention provides a tubular outer member rotatable about a first axis, a cylindrical outer member disposed inside the outer member, and An inner member rotatable about a second axis disposed in a plane including the first axis, and formed at predetermined intervals in a circumferential direction on an inner periphery of the outer member;
A plurality of grooves extending in the first axial direction; a plurality of shafts formed to protrude from an outer periphery of the inner member; and a plurality of shafts attached to an outer periphery of each shaft, respectively, and a longitudinal direction of each of the grooves. An annular torque transmitting member which is movable in the axial direction, wherein the plurality of shaft portions and each of the torque transmitting members are configured to be relatively movable in a longitudinal direction of each shaft portion, and an outer peripheral surface of each of the shaft portions. In a constant velocity universal joint, an arc-shaped portion is formed, an arc-shaped portion is formed on the inner peripheral surface of the plurality of torque transmitting members, and a lubricant is sealed inside the outer member.
A radius corresponding to at least a part of the arc-shaped portion of the shaft portion and a radius corresponding to the arc-shaped portion of the torque transmitting member are set to different values.

[0010] According to the present invention, the outer peripheral surface of the shaft portion and the inner peripheral surface of the torque transmitting member abut, and torque is transmitted via each abutting portion. Is transmitted. Further, the torque transmitting member moves in the longitudinal direction of the groove in accordance with the change in the rotational phase of the outer member and the inner member, and the torque transmitting member has a torque transmitting surface that is set orthogonal to the first axis. The peripheral surface and the outer peripheral surface of the shaft portion are in contact with each other, and the constant velocity between the outer member and the inner member is maintained.

Here, since the radius of curvature corresponding to at least a part of the arc-shaped portion of the shaft portion and the radius of curvature corresponding to the arc-shaped portion of the torque transmitting member are set to different values, each of the arc-shaped portions is different. A gap is formed between them, and the lubricant easily intervenes between the sliding surfaces of the shaft portion and the torque transmitting member.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 2 is a conceptual plan view of a front wheel drive vehicle 1 to which the constant velocity universal joint of the present invention is applied. That is, the front of the front wheel drive vehicle 1 is provided with the engine 2
And a transmission 3 for converting torque output from the engine 2, and a differential 4 connected to an output side of the transmission 3. A pair of front drive shafts 5 are connected to the output side of the differential 4, and the pair of front drive shafts 5 are connected to the front wheels 6 respectively. That is,
The pair of front drive shafts 5 are arranged in the width direction of the front wheel drive vehicle 1.

The pair of front drive shafts 5 includes a tripod joint 7 which is a constant velocity universal joint, a shaft 8, and another constant velocity universal joint 9. That is, the tripod joint 7 is provided at one end of the shaft 8, and the constant velocity universal joint 9 is provided at the other end of the shaft 8. And one tripod joint 7
Are connected to the differential 4 side, and the other constant velocity universal joint 9 is connected to the front wheel 6 side. The constant velocity universal joint 9 is exemplified by a bar field type joint.

FIG. 3 shows the structure of the tripod joint 7 connected to the right wheel 6 in FIG. FIG.
FIG. 3 is a partial side end view of the tripod joint 7, and FIG. 3 corresponds to a state in which the first axis A1 of the outer race 10 and the second axis of the shaft 8 are positioned substantially linearly for convenience. Thus, a tripod joint 7 is shown. In FIG. 3, the shaft 8 is omitted for convenience.

FIG. 4 is a front sectional view showing the tripod type joint 7 attached to the vehicle.
In FIG. 4, the second axis B1 of the shaft 8 and the first axis A1 of the outer race 10 are arranged on the same plane, and the first axis A1 and the second axis B1 have a predetermined operating angle (connection). Angle) θ1 is set. Further, FIG.
It is a top view which shows the principal part of the tripod type joint 7. FIG.
FIG. 1 shows the first axis A of the outer race 10 for convenience.
1 and the second axis B1 of the shaft 8 are shown in a state of being linearly arranged. The tripod joint 7 connected to the left wheel 6 in FIG.
Since it is configured to be plane-symmetric with the tripod joint 7 shown in FIG.

The tripod type joint 7 has an outer race 10 having a bottomed cylindrical shape, and a shaft 8 having one end disposed inside the outer race 10. As shown in FIG. 4, the outer race 10 is configured to be rotatable about a first axis A1, and the shaft 8 is configured to be rotatable about a second axis B1. A spline shaft (not shown) centering on the first axis A1 is integrally formed on the bottom of the outer race 10. The differential 4 is a side gear (not shown).
And the spline shaft and the side gear are connected. Further, three grooves 11 extending in the first axial direction are formed on the inner periphery of the outer race 10. The grooves 11 are spaced at equal intervals in the circumferential direction,
They are arranged at intervals of 20 degrees.

Each groove 11 has a bottom surface 12 and an inner wall surface 13. The bottom surface 12 is configured substantially parallel to the first axis A1, and a pair of inner wall surfaces 13 are connected to both sides of the bottom surface 12 in the width direction. In a plane orthogonal to the first axis A <b> 1, the shape of the pair of inner wall surfaces 13 is curved so as to protrude outside the outer race 10. That is, the pair of inner wall surfaces 13 are configured to be mutually plane-symmetric.

Further, one end of the shaft 8 is disposed inside the outer race 10, and an annular tripod member 14 is spline-fitted to the outer periphery of the end of the shaft 8 on the outer race 10 side. Shaft 8
, Two snap rings 15A are attached, and the shaft 8 and the tripod member 14 are positioned in the second axial direction of the shaft 8 by the snap rings 15A.

Then, on the outer periphery of the tripod member 14,
Three trunnions 15 projecting outward are formed. The trunnions 15 are arranged at equal intervals in the circumferential direction, specifically, at 120 ° intervals. Each trunnion 1
Reference numeral 5 has a substantially cylindrical shape. Tripod member 1
The protrusion amount of each trunnion 15 in the radial direction of 4 is set to a value such that the outer peripheral surface of each trunnion 15 reaches between the pair of inner wall surfaces 13.

The shape of the outer circumferential surface 16 of the trunnion 15 is curved so as to protrude outward in a plane including the first center line C1 of the trunnion 15. Next, the shape of the outer peripheral surface 16 in a first plane orthogonal to the first center line C1 of the trunnion 15 will be described with reference to FIG. On the outer periphery of the trunnion 15, four arc-shaped portions 1 are arranged in the circumferential direction.
6A and 16C are formed.

Here, the arc-shaped portion 16A and the arc-shaped portion 1
6B are arranged adjacent to each other, and the arc-shaped portions 16C and 16D are arranged adjacent to each other. The length of each of the arc-shaped portions 16A, 16D in the circumferential direction is set to less than one-fourth of the entire circumference of the outer peripheral surface 16 and is set to be substantially the same as each other. Further, the arc-shaped portion 16A and the arc-shaped portion 16C are arranged on opposite sides of the center G1 through which the first center line C1 of the trunnion 15 passes, and the arc-shaped portion 16B and the arc-shaped portion 16D are connected to the center G1. Are arranged on the opposite side.

Then, the arc-shaped portion 16A and the arc-shaped portion 1
6D, and between the arc-shaped portion 16B and the arc-shaped portion 16
Flat portions 16E are respectively formed between the flat portions 16C and C. That is, a connection portion 16F between the arc-shaped portions 16A and 16B and a connection portion 16F between the arc-shaped portions 16C and 16D are arranged to face the grooves 11, respectively. In other words, outer race 10
In the case where torque is transmitted between shaft 1 and shaft 8, connecting portion 16F is provided in a torque transmitting surface set orthogonal to first axis A1. Further, each flat surface 16E is arranged in the longitudinal direction of the groove 12. The side surface shape of each flat portion 16E is configured to be substantially circular as shown in FIG.

In the first plane orthogonal to the first center line C1, the centers of curvature F1 to F4 corresponding to the arc-shaped portions 16A to 16D are set at different positions. First, the center of curvature F1 of the arc-shaped portion 16A
Are arranged between the arc-shaped portion 16C and the center G1. The center of curvature F2 of the arc-shaped portion 16B is arranged between the arc-shaped portion 16D and the center G1.

Further, the center of curvature F3 of the arc-shaped portion 16C
Are arranged between the arc-shaped portion 16A and the center G1. Furthermore, the center of curvature F4 of the arc-shaped portion 16D is
It is arranged between the arc-shaped portion 16B and the center G1.
The distances from the centers of curvature F1 to F4 to the center G1 are set to be the same. Then, the center of curvature F1 and the center of curvature F
The center G1 is set on a line segment (not shown) connecting to the line No.3. The center G1 is set on a line (not shown) connecting the centers of curvature F2 and F4. The two line segments are set at positions that intersect at right angles.

According to the above configuration, the trunnion 1 is positioned in the first plane orthogonal to the first center line C1 of the trunnion 15.
The shape of the outer peripheral surface 16 of 5 is set to a substantially elliptical shape, in other words, a track shape. That is, the first center line C
1, and the shape of the outer peripheral surface 16 is configured to be symmetric with respect to a plane passing through the center of the two flat surfaces 16E.

Further, an annular roller assembly 17 is attached to the outer periphery of each trunnion 15. The roller assembly 17 is formed annularly around the second center line C2. The roller assembly 17 includes an inner ring 18, a needle 19, and an outer roller 20.
And a snap ring 21. The inner ring 18 is fitted on the outer periphery of the trunnion 15.

The inner ring 18 is formed in a cylindrical shape, and as shown in FIG. 3, the length of the inner ring 18 in the second center line direction is set substantially equal to the amount of protrusion of the trunnion 15. Next, the shape of the inner ring 18 in a second plane orthogonal to the second center line C2 will be described with reference to FIG. FIG. 1 is a plan view corresponding to a state in which the first center line C1 of the trunnion 15 and the second center line C2 of the inner ring 18 are linearly located. The second plane is in the same state.

The shape of the inner peripheral surface 22 of the inner ring 18 is a perfect circle in the second plane. That is, the inner peripheral surface 22 is the second ring of the inner ring 18.
The center of curvature G1 is set on the center line C2.
Further, the radius of curvature of the inner peripheral surface 22 is determined by each of the arc-shaped portions 16A,.
The radius of curvature is set smaller than each radius of curvature of 16D. FIG.
For convenience, the center of curvature and trunnion 1
The same symbol G1 is assigned to the center of 5. Thus, in the second plane or the third plane, the center of curvature G
1 and the centers of curvature F1 to F4 are set (offset) at different positions.

The inner diameter of the inner ring 18 is set uniformly in the direction of the second center line. Further, the distance between the two connection portions 16F formed on the trunnion 15 is set slightly shorter than the inner diameter of the inner ring 18. As described above, the inner peripheral surface 2 of the inner ring 18
2 is formed in a substantially perfect circular shape, and the trunnion 15 is formed in a substantially elliptical shape, so that the two connecting portions 16F and the inner peripheral surface 22 are in contact with each other, and the respective arc-shaped portions 16A, 16A, A gap G1 is formed between 16D and the inner peripheral surface 22. A gap H1 is formed between each flat surface 16E and the inner peripheral surface 22.

The outer roller 20 is arranged outside the inner ring 18, and the outer roller 20 and the inner ring 18 are arranged concentrically. Furthermore, a plurality of needles 19 are arranged between the inner ring 18 and the outer roller 20. The inner ring 18 and the outer roller 20 are configured to be relatively rotatable via the plurality of needles 19.

Further, two annular grooves 23 are formed on the inner peripheral surface of the outer roller 20. The snap ring 21 is attached to each annular groove 23,
The inner diameter of the snap ring 21 is set to a value smaller than the outer diameter of the inner ring 18 and larger than the inner diameter of the inner ring 18. The inner ring 18 and the plurality of needles 19 are arranged between the two snap rings 21. Thus, the inner ring 18
And the outer roller 20 are two snap rings 2
1, the inner ring 18 and the outer roller 20 are positioned and fixed in the second center line direction.

The outer roller 20 is formed in an annular shape, and a curved surface 24 is formed on the outer periphery of the outer roller 20. The center of curvature of the curved surface 24 is set in a second plane including the second center line C1 of the outer roller 20. And it is curved so that it may protrude outside the outer roller 20. Also, the curved surface 24 and the inner wall surface 13 of the groove 11 are in contact with each other at two points in the width direction of the inner wall surface 13, and the outer roller 20 is movable in the longitudinal direction of the groove 11. The shape and dimensions of the inner surface 24 and the inner surface 13 are set.

The trunnion 15 and the roller assembly 17
Is configured as described above, the roller assembly 1
7 is capable of pivoting and turning relative to the trunnion 15. Actually, since the roller assembly 17 is disposed in the groove 11, the roller assembly 17
5 can swing (swing) in a plane including the first center line C1. Further, the roller assembly 17 and the trunnion 15 are relatively movable in a first center line direction of the trunnion 15.

Further, one end of a bellows-shaped boot 25 is fixed to the outer periphery of the open end side of the outer race 10, and the other end of the boot 25 is fixed to the shaft 8. Thus, the inside of the outer race 10 is sealed in a liquid-tight manner by the boot 25, and grease (not shown) is sealed as a lubricant in the sealed space L1.

The outer race 10 is made of a material such as carbon steel or chrome steel, the shaft 8 is made of a material such as carbon steel or boron steel, and the tripod member 14 is made of a material such as chrome steel. . The outer roller 20 and the inner ring 18 are made of a material such as bearing steel or chrome steel, and the needle 19 is made of a material such as bearing steel.

Here, the correspondence between the configuration of the embodiment and the configuration of the present invention will be described. That is, the outer race 10
Corresponds to the outer member of the present invention, and the tripod member 14 and the shaft 8 correspond to the inner member of the present invention. Further, the trunnion 15 corresponds to the shaft portion of the present invention, the roller assembly 17 corresponds to the torque transmitting member of the present invention, and the inner peripheral surface 22 corresponds to the arc-shaped portion of the present invention.

Next, a method of processing the tripod member 14 will be described. As shown in FIG. 5, the cold-forged crude material (tripod member) 50 is attached to the center G of a predetermined trunnion 15.
1 and the outer peripheral surface 16 of the trunnion 15 is ground by the grinding wheel 51. Here, the grinding wheel 51 can reciprocate in a direction orthogonal to the first center line of the trunnion 15, and the grinding wheel 51 reciprocates with a change in the rotation phase of the trunnion 15, whereby the trunnion 15 is moved. Is processed into the shape shown in FIG.

Further, the traveling operation of the front wheel drive vehicle 1 shown in FIG. 2 will be described. The torque output from the engine 2 is transmitted to each front drive shaft 5 via a transmission 3 and a differential 4. Specifically, the torque output from the differential 4 causes the outer race 10 to rotate in a predetermined direction. The torque of the outer race 10 is transmitted to the shaft 8 via the roller assembly 17 and the tripod member 14.
More specifically, the inner peripheral surface 22 of the inner roller 18
And the torque is transmitted through a contact area between the trunnion 15 and one of the connection portions 16F. Which of the two connection portions 16F transmits the torque is determined by the rotation direction of the outer race 10 and the shaft 8.

As described above, the first axis A1 and the second axis B
1 and the predetermined operating angle θ1, the roller assembly 17 moves in the longitudinal direction of the groove 11 with the rotation of the outer race 10, and the roller assembly 17 and the trunnion 15 The roller assembly 17 swings relative to the trunnion 15 by moving relative to one center line. By these operations, the connection portion 16F between the inner peripheral surface 22 of the inner roller 18 and each tripod 15 is provided in the torque transmission surface set orthogonal to the first axis A1.
Is set, and the constant speed between the rotation of the outer race 10 and the rotation of the shaft 8 is maintained. Thus, the torque of the shaft 8 is transmitted to the front wheels 6, and the front wheel drive vehicle 1 runs.

When torque is transmitted between the outer race 10 and the shaft 8, the trunnion 15
When the entire roller assembly 17 rolls in the groove 11 integrally based on conditions such as the frictional force between the outer roller 20 and the inner ring 1,
8 may move relative to each other via the rolling element 19, and only the outer roller 20 may roll in the groove 11. And
In this embodiment, any of the above cases is included in the rolling of the roller assembly 17. In addition, while the front wheel drive vehicle 1 is traveling, the operating angle θ1 fluctuates depending on conditions such as the vertical movement of the front wheels 6.

On the other hand, the sliding surface between the outer roller 20 and the groove 11 is lubricated by the grease sealed in the space L1. In the circumferential direction of the outer peripheral surface 16 of the trunnion 15, the connection portion 16 </ b> F and the inner peripheral surface 22 are in point contact with each other, and the gap H 1 and the gap G 1 formed between the trunnion 15 and the inner roller 18 are in Grease enters. For this reason, grease easily intervenes on the sliding surface between the trunnion 15 and the inner roller 18, specifically, the contact portion between the connecting portion 16F and the inner peripheral surface 22 that contribute to the transmission of torque. The lubrication performance of the part is improved, and the frictional resistance is suppressed. Therefore, heat generation, abrasion, flaking, adhesion, and the like on the sliding surface between the trunnion 15 and the inner roller 18 are suppressed, and the durability of the tripod joint 7 is improved.

As a result, the outer peripheral surface 16 of the trunnion 15
Alternatively, the inner peripheral surface 22 of the inner roller 18 does not need to be subjected to a low-friction coating for applying a solid lubricant such as molybdenum disulfide or a surface treatment such as lubricite. Time can be reduced, and manufacturing costs can be reduced.

By the way, when the roller assembly 17 is moving in the longitudinal direction of the groove 11, the outer race 10 is in contact with the curved surface 24 of the outer roller 20 and the inner wall surface 13 of the groove 11. A frictional force acts in the first axis direction. This frictional force is applied to one roller assembly 17.
Each time, 2π / 3 is defined as one cycle, and is a forcing force (load) in the axial direction represented by a sine curve. In the tripod type joint 7, the torque is transmitted by the three roller assemblies 17, so that the forcing force of three cycles during one rotation of the shaft 8 and the outer race 10, that is, the rotation tertiary Of the outer race 1 (in other words, the fluctuation component of the induced thrust force)
Acts on zero.

On the other hand, when the trunnion 15 and the inner roller 18 relatively move in the height direction of the trunnion 15, the outer peripheral surface 16 of the trunnion 15 and the inner roller 1 are moved.
The frictional force between the roller assembly 17 and the inner peripheral surface 22 of the roller assembly 17
Moment acts around the center of curvature of the curved surface 24 of
In FIG. 3, the force causes the roller assembly 17 to rotate clockwise or counterclockwise. The direction of the rotational force acting on the roller assembly 17 depends on which of the outer race 10 or the tripod member 14 is the driving member, the rotational direction of the outer race 10 and the tripod member 14, and the direction of the trunnion 15 and the inner roller 22. It is determined based on the relative movement direction.

Here, the case where the outer race 10 is a driving member, the tripod member 14 is a driven member, and the outer race 10 and the tripod member 14 rotate counterclockwise in FIG. 3 will be described as an example. in this case,
3, torque is transmitted through a contact portion between the connection portion 16F located on the right side and the inner peripheral surface 22, and a frictional force acts on the contact portion in the vertical direction in FIG.

First, when the inner roller 18 moves upward relative to the trunnion 15, a counterclockwise moment is generated around the center of curvature of the curved surface 24 shown on the right side of FIG. Works. Therefore,
A rotational force acts in a direction to rotate the roller assembly 17 counterclockwise in FIG. When the inner roller 18 moves downward relative to the trunnion 15, a clockwise moment acts around the center of curvature of the curved surface 24 shown on the right side of FIG. 3 due to the frictional force. Accordingly, a rotational force acts in a direction to rotate the roller assembly 17 clockwise in FIG. In this way, when a rotational force in a predetermined direction acts on the roller assembly 17, the outer roller 2
There is a possibility that the frictional resistance between the groove 0 and the groove 11 is increased, and the forcing force of the third rotation is increased.

However, in this embodiment, since the frictional resistance on the sliding surface between the trunnion 15 and the inner roller 18 is suppressed, the moment acting around the center of curvature of the curved surface 24 of the outer roller 20 is suppressed. Is done. Therefore, the sliding resistance between the groove 11 and the outer roller 20 is suppressed, and the forcing force of the third rotation is suppressed.

Therefore, the outer race 10 is less likely to vibrate in the first axial direction, and idling vibration caused by the vibration of the outer race 10 in the axial direction during the idling of the engine 2 is suppressed. In addition, when the front wheel drive vehicle 1 starts moving, the body sway caused by the vibration of the outer race 10 in the axial direction as a vibration source is suppressed, and the riding comfort of the front wheel drive vehicle 1 is improved. Further, noise such as a beat sound or a muffled sound when the front wheel drive vehicle 1 is traveling at a predetermined speed is suppressed, so that quietness can be improved.
That is, so-called NV (noise vibration)
Performance is improved.

Further, heat generation on the sliding surface between the inner roller 18 and the trunnion 15 is suppressed, and heat generation on the sliding surface between the outer roller 20 and the groove 11 is suppressed. The conversion of a part of the torque transmitted by the motor into frictional heat can be suppressed. Therefore, a reduction in the power transmission efficiency of the tripod joint 7 can be suppressed. Further, deterioration and seizure of the grease due to heat generation are suppressed. Also, when the torque of the shaft 8 is transmitted to the outer race 10 via the roller assembly 17, the third-order forcing force is suppressed by the same operation as described above.

In the present invention, the shape of the outer peripheral surface of the trunnion is formed in a perfect circular shape, and the center of curvature is set in a part of the inner peripheral surface of the inner roller at a position different from the center of curvature of the outer peripheral surface. It is also possible to adopt a configuration in which an arc-shaped portion is provided, and to form a gap between the inner peripheral surface and the outer peripheral surface. In this case, the radius of each arc-shaped portion is set to be larger than the radius of the outer peripheral surface.

The present invention is also applicable to a tripod joint having a configuration in which the outer diameter of the trunnion is set uniformly in the height direction. In the tripod joint of this configuration, the roller assembly and the trunnion are
The roller assembly does not swing with respect to the trunnion, only moving relative to the height of the trunnion. Therefore, the first center line of the trunnion and the second center line of the roller assembly are always kept in a state of coincidence.

[0052]

As described above, according to the present invention, the outer peripheral surface of the shaft portion and the inner peripheral surface of the torque transmitting member come into contact with each other, and the torque is transmitted through each contact portion, and thus the outer member. Transmission of torque is performed between the motor and the inner member. Further, the torque transmitting member moves in the longitudinal direction of the groove in accordance with the change in the rotation phase of the outer member and the inner member, and the constant velocity between the outer member and the inner member is maintained.

Here, the radius of curvature corresponding to at least a part of the arc-shaped portion of the shaft and the radius of curvature corresponding to the arc-shaped portion of the torque transmitting member are set to different values. A gap is formed between them, so that the lubricant easily intervenes in the sliding region between the shaft portion and the torque transmitting member. Therefore, the frictional force generated in the sliding area between the inner peripheral surface of the torque transmitting member and the outer peripheral surface of the shaft portion is reduced, and heat generation, wear, flaking, adhesion, etc. of the shaft portion or the torque transmitting member are suppressed, and The durability of the universal joint is improved.

[Brief description of the drawings]

FIG. 1 is a partial plan view of a tripod joint according to an embodiment of the present invention.

FIG. 2 is a plan view showing a schematic configuration of a front wheel drive vehicle equipped with a tripod joint according to an embodiment of the present invention.

FIG. 3 is a side end view of the tripod joint according to the embodiment of the present invention.

FIG. 4 is a front sectional view of a tripod joint according to an embodiment of the present invention.

FIG. 5 is a conceptual diagram showing a method for processing a tripod member of a tripod joint according to an embodiment of the present invention.

[Explanation of symbols]

8 ... shaft, 10 ... outer race, 11 ... groove,
14: tripod member, 15: trunnion, 16
A, ~ 16D: arc-shaped part, 17: roller assembly,
A1: first axis, B1: second axis.

Claims (1)

[Claims] A cylindrical outer member rotatable about a first axis; a cylindrical outer member disposed inside the outer member;
An inner member rotatable about a second axis disposed in a plane including the first axis, formed at predetermined intervals in a circumferential direction on an inner periphery of the outer member, and A plurality of grooves extending in one axis direction, a plurality of shafts formed to protrude on the outer periphery of the inner member, and attached to the outer periphery of each shaft, and movable in the longitudinal direction of each groove; An annular torque transmitting member, wherein the plurality of shaft portions and the torque transmitting members are configured to be relatively movable in a longitudinal direction of each shaft portion, and an arc-shaped portion is formed on an outer peripheral surface of each shaft portion. Is formed, an arc-shaped portion is formed on an inner peripheral surface of the plurality of torque transmitting members, and a lubricant is sealed inside the outer member. At least one of the arc-shaped portions of the shaft portion is provided. Radius corresponding to the part and the arc of the torque transmitting member A constant velocity universal joint, wherein a radius corresponding to a shape portion is set to a different value.