CN118208500A - Tripod constant velocity universal joint - Google Patents

Abstract

A tripod constant velocity universal joint capable of stably exhibiting desired workability and torque transmission performance over a long period of time is provided with a displacement regulating portion (P) provided on a boss portion (6) of a tripod member (5), wherein the displacement regulating portion (P) is brought into contact with a small inner diameter surface (3 Ba) of a cup portion (3) before an outer washer (12) comes into contact with both a roller (10) and a retainer ring (11) when an outer joint member (2) and the tripod member (5) are angularly displaced relative to each other to an operating angle (theta 1) exceeding a predetermined maximum operating angle (theta max), thereby regulating further expansion of the operating angle.

Description

Tripod constant velocity universal joint

Technical Field

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

Background

The constant velocity universal joint has a structure in which two shafts on a driving side and a driven side are coupled to each other and torque can be transmitted at a constant velocity even when the two shafts acquire an operating angle, and is roughly classified into a fixed type allowing only angular displacement of the two shafts and a sliding type allowing angular displacement and axial displacement of the two shafts. As a sliding type constant velocity universal joint, for example, there is a tripod type joint described in japanese patent application laid-open No. 2001-330049 (patent document 1).

As shown in fig. 5A and 5B, the tripod type constant velocity universal joint described in patent document 1 includes: an outer joint member 100 having a bottomed cylindrical cup portion 101, the cup portion 101 having three track grooves 102 extending in the axial direction defined therein at equal intervals in the circumferential direction; and a coupling inner disposed in the inner space of the cup-shaped portion 101. The cup portion 101 of the outer joint member 100 is formed such that three circular arc-shaped large diameter portions 101A and three circular arc-shaped small diameter portions 101B are alternately arranged in the circumferential direction, and the raceway grooves 102 are provided radially inward of the large diameter portions 101A.

The tripod unit as an inner member of the coupling includes: a tripod member 103 having a cylindrical boss 103A to which a shaft member, not shown, is coupled so as to be able to transmit torque, and three leg shafts 103C extending radially outward from the outer peripheral surface of the boss 103A are provided at equal intervals in the circumferential direction; and a total of three rollers 105 accommodated in the corresponding track grooves 102 in a state rotatably supported by the foot shaft 103C via the plurality of needle rollers 104. The track groove 102 has a pair of roller guide surfaces 102a, and when the outer joint member 100 is angularly displaced and/or axially displaced relative to the tripod member 103, the rollers 105 accommodated in the track groove 102 roll on the pair of roller guide surfaces 102 a.

A roller 105 fitted to the outer periphery of the foot shaft 103C via a needle roller 104 is slidably movable in the radial direction (the axial direction of the foot shaft 103C), and an outer washer 106 engageable with the roller 105 and the needle roller 104 in the radial direction is mounted on the outer peripheral surface of the foot shaft 103C at a position radially outside the portion to be fitted with the needle roller 104. Further, an annular groove is formed in the outer peripheral surface of the foot shaft 103C at a position radially outward of the portion to be fitted with the outer washer 106, and the outer washer 106 (and the roller 105 and the needle roller 104) is prevented from coming off the foot shaft 103C by a retainer ring 107 fitted in the annular groove.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 2001-330049

Disclosure of Invention

Problems to be solved by the invention

However, as shown in fig. 6, when the tripod constant velocity universal joint having the above-described configuration obtains the operating angle θ (when the outer joint member 100 is angularly displaced relative to the tripod member 103), the (foot shaft 103C of the) tripod member 103 is slidingly moved with respect to the roller 105 restrained by the pair of guide surfaces 102a dividing the raceway groove 102, and therefore the center (center axis) Ct of the tripod member 103 is eccentric with respect to the center (center axis) Cj of the outer joint member 100. The larger the working angle θ, the larger the eccentric amount.

As described above, when the joint obtains the operating angle θ and the tripod member 103 is eccentric with respect to the outer joint member 100, the roller 105 approaches the outer diameter end of the outer washer 106 mounted on the foot shaft 103C. The larger the eccentric amount (operating angle θ) of the tripod member 103, the closer the roller 105 is to the outer diameter end of the outer washer 106. In a tripod type constant velocity universal joint, which is one type of a sliding type constant velocity universal joint, since the relative axial displacement of the outer joint member 100 and the tripod pin member 103 is allowed, there is a possibility that the outer joint member 100 and the tripod pin member 103 may be angularly displaced beyond the maximum operating angle when the joint is in use (torque transmission) depending on the axial relative positions of the cup portion 101 of the outer joint member 100 and the tripod pin member 103. Further, for example, when the outer joint member 100 and the tripod member 103 are largely angularly displaced so as to exceed the maximum operating angle at the time of joint use, for example, when the tripod constant velocity universal joint is transported, the outer washer 106 may come into contact with both the roller 105 and the retainer ring 107, and the outer washer 106 may be deformed. If the outer washer 106 is deformed, etc., there is a possibility that the three-ball pin member 103 may be out of position with respect to the roller 105, or the roller 105 may be damaged in its anti-slip function, etc., and the workability and torque transmission performance of the coupling may be degraded.

In view of the above-described circumstances, an object of the present invention is to provide a tripod constant velocity universal joint capable of stably exhibiting desired workability and torque transmission performance over a long period of time by preventing, as much as possible, deformation of an outer washer or the like attached to a foot shaft of a tripod member so as to be engageable with a roller as a torque transmission member, with angular displacement of the joint.

Means for solving the problems

The present invention proposed to achieve the above object is provided with:

An outer joint member having a bottomed cylindrical cup portion, the cup portion having three axially extending track grooves equally spaced apart in a circumferential direction on an inner periphery thereof;

A tripod member having a cylindrical boss to which the shaft member is coupled so as to be capable of transmitting torque, and three leg shafts extending radially outward from an outer peripheral surface of the boss are provided at equal intervals in a circumferential direction;

A roller housed in the corresponding raceway groove in a state rotatably supported by the foot shaft via a plurality of needle rollers; and

An outer washer engageable with the needle roller and the roller, and a retainer engageable with the outer washer, which are fitted to the outer peripheral surface of the foot shaft radially outward of the needle roller,

The cup-shaped portion is formed in a shape of a non-perfect circle in cross section in which three circular arc-shaped large-diameter portions and small-diameter portions are alternately arranged in the circumferential direction, and a rolling roller guide surface for guiding a roller is provided on the inner surface of a connecting portion connecting the large-diameter portion and the small-diameter portion,

When the outer joint member and the tripod member are angularly displaced relative to each other beyond a predetermined maximum operating angle, the displacement restricting portion is provided in the boss portion and is brought into contact with the inner diameter surface of the small diameter portion before the outer washer comes into contact with both the roller and the retainer ring, thereby restricting the angular displacement by which the operating angle of the outer joint member and the tripod member is further enlarged.

According to the above configuration, since the boss portion of the tripod member is provided as a so-called angle limiter which restricts the angular displacement of the outer joint member relative to the tripod member beyond a predetermined operating angle, the outer washer can be prevented from being deformed or the like due to contact between the outer washer and both the roller and the retainer ring. The boss portion of the tripod member is a portion to which the shaft member is coupled so as to be able to transmit torque, and has a sufficiently thick wall thickness and excellent mechanical strength as compared with a general outer washer made of a thin metal plate. Therefore, even if the boss (displacement restricting portion provided) is in contact with the inner diameter surface of the small diameter portion, the problem of deformation or the like occurring in the boss can be avoided.

In the tripod type constant velocity universal joint having the above configuration, a tapered surface having an angle equal to the maximum operating angle θmax with respect to the center axis of the tripod type member may be provided on the outer peripheral surface of the boss portion, and in this case, an end portion (minimum diameter portion) on the end surface side of the boss portion among the tapered surfaces may function as a displacement restricting portion. According to this configuration, the displacement restricting portion (functioning as an angle limiter) can be provided only by providing the tapered surface of the projection portion at a predetermined angle on the outer peripheral surface, and therefore deformation prevention of the outer gasket can be easily and inexpensively achieved.

Effects of the invention

As described above, according to the present invention, deformation of the outer race that is mounted on the foot shaft of the tripod member and functions as a roller (and needle roller) drop preventing member can be prevented as much as possible, and therefore, a tripod constant velocity universal joint that can stably exhibit desired workability and torque transmission performance over a long period of time can be provided.

Drawings

Fig. 1A is a front view of a tripod type constant velocity universal joint according to an embodiment of the present invention in a state where the working angle is 0 °.

FIG. 1B is a cross-sectional view taken along line A-A of FIG. 1A.

Fig. 2 is a longitudinal sectional view showing a state in which the constant velocity universal joint shown in fig. 1 attains the maximum operating angle θmax.

Fig. 3 is an enlarged view of a portion B in fig. 2.

Fig. 4 is a longitudinal sectional view showing a state in which the constant velocity universal joint shown in fig. 1 obtains an operating angle θ1 that is larger than the maximum operating angle.

Fig. 5A is a front view of a conventional tripod type constant velocity universal joint in a state where the operating angle is 0 °.

Fig. 5B is an X-ray sectional view of fig. 5A.

Fig. 6 is a longitudinal sectional view showing a state in which the constant velocity universal joint shown in fig. 5 obtains an operating angle.

Reference numerals illustrate:

1. Tripod constant velocity universal joint

2. Outer coupling member

3. Cup-shaped portion

3A major diameter portion

3Aa (large diameter portion) inner diameter surface

3B small diameter portion

3Ba (inner diameter face of small diameter portion)

4. Raceway groove

4A guide surface

5. Tripod member

6. Raised portion

6B conical surface

7. Shaft hole

8. Foot shaft

9. Needle roller

10. Roller

11. Retainer ring

12. Outside gasket

Center of Cj outside coupling member (center axis)

Center of Ct tripod member (center axis)

S-axis component

P-displacement limiting part

Θmax maximum working angle

Θ1 exceeds the operating angle of the maximum operating angle.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Fig. 1A is a front view of a tripod type constant velocity universal joint 1 according to an embodiment of the present invention in a state where the working angle is 0 °, and fig. 1B is a cross-sectional view taken along line A-A in fig. 1A. The tripod type constant velocity universal joint 1 (hereinafter, also simply referred to as "constant velocity universal joint 1") is one type of a sliding type constant velocity universal joint that allows angular displacement and axial displacement of both shafts on the driving side and the driven side, and constitutes a drive shaft together with a shaft member S (indicated by a broken line in fig. 1B) having one end connected to a tripod member 5, a fixed type constant velocity universal joint, not shown, connected to the other end of the shaft member S, or the like. The drive shaft is mounted on an automobile, for example, and transmits rotational torque output from a drive source such as an engine or an electric motor mounted on a chassis to drive wheels. In this drive shaft, the tripod type constant velocity universal joint 1 is disposed on the drive source side, and the fixed type constant velocity universal joint is disposed on the drive wheel side.

The constant velocity universal joint 1 includes: an outer joint member 2 having a bottomed cylindrical cup portion 3, and a tripod pin unit as a joint inner member disposed in an inner space of the cup portion 3. The tripod unit includes a tripod member 5, a plurality of needle rollers 9, and a cylindrical roller 10. Hereinafter, "axial direction", "radial direction", and "circumferential direction" used in describing the structure and construction of the constant velocity universal joint 1 are, unless otherwise specified, the direction along the center axis Cj of the outer joint member 2 (the left-right direction of the drawing sheet of fig. 1B), the radial direction of a circle centered on the center axis Cj, and the circumferential direction of a circle centered on the center axis Cj, respectively.

The tripod member 5 integrally has: a cylindrical boss 6 formed with a shaft hole 7; and three leg shafts 8 arranged at equal intervals (120 ° intervals) in the circumferential direction and extending radially outward from the outer peripheral surface of the boss 6. A spline (including serrations) in which a plurality of axially extending convex portions are arranged at equal intervals in the circumferential direction is formed on the inner surface of the shaft hole 7 (inner peripheral surface of the boss portion 6), and the shaft member S is coupled to the spline so as to be able to transmit torque.

Each of the foot shafts 8 provided to the tripod member 5 has a constant diameter (cylindrical) outer peripheral surface 8a extending in a direction orthogonal to the central axis Ct of the tripod member 5, and the roller 10 is rotatably fitted to the outer peripheral surface 8a via a plurality of needle rollers 9. The needle rollers 9 are disposed on the outer peripheral surface 8a so as to be capable of rolling along the circumferential direction of the foot shaft 8, and the radially outer and inner end portions of the needle rollers 9 are respectively in contact with an outer washer 12 fitted near the shaft end of the foot shaft 8 and an inner washer 13 fitted at the root of the foot shaft 8. The outer gasket 12 and the inner gasket 13 are annular members each made of a thin metal plate having a thickness of about 1.0 mm.

As shown in fig. 3 in an enlarged form, an annular groove 8b is formed in the outer peripheral surface 8a of the foot shaft 8 at a position radially outward of the portion to be fitted of the outer washer 12, and a retainer ring 11 engageable with the outer washer 12 in the radial direction is fitted in the annular groove 8 b. The outer washer 12 and the needle roller 9 are restricted from being pulled out of the foot shaft 8 by the retainer ring 11. The outer gasket 12 is formed in a substantially L-shaped cross section, and integrally includes: a disk portion 12a fitted to the outer peripheral surface 8a of the foot shaft 8; a cylindrical portion 12b extending in a radial direction (an axial direction of the foot shaft 8); and an expanded diameter portion 12c that gradually expands in diameter toward the radial outside. The outer diameter Da of the cylindrical portion 12b of the outer washer 12 is set smaller than the inner diameter Dr of the roller 10 by a predetermined amount, and the (maximum) outer diameter Db of the enlarged diameter portion 12c of the outer washer 12 is set larger than the inner diameter Dr of the roller 10 by a predetermined amount. Therefore, the roller 10 fitted to the outer periphery of the foot shaft 8 can slide in the radial direction by a predetermined amount, but is restricted from being pulled out from the foot shaft 8.

Three track grooves 4 each accommodating a roller 10 are provided at equal intervals (120 ° pitch) in the circumferential direction on the inner periphery of the cup portion 3 of the outer joint member 2. Each of the track grooves 4 has a pair of roller guide surfaces 4a that guide the rolling motion of the rollers 10 while facing each other, and is formed in a linear shape (parallel to the central axis Cj of the outer joint member 2) including the roller guide surfaces 4a extending in the axial direction. The cup-shaped portion 3 is formed in a non-circular cross section in which three circular arc-shaped large diameter portions 3A and circular arc-shaped small diameter portions 3B each having an outer diameter and an inner diameter smaller than the large diameter portions 3A are alternately arranged in the circumferential direction, and an inner surface of a connecting portion 3C connecting the large diameter portions 3A and the small diameter portions 3B functions as a roller guide surface 4 a. The inner diameter surface (large inner diameter surface) 3Aa of the large diameter portion 3A and the inner diameter surface (small inner diameter surface 3 Ba) of the small diameter portion 3B are each formed in a straight line parallel to the central axis Cj of the outer joint member 2. The contact pattern between the roller 10 and the roller guide surface 4a is angular contact (two-point contact) or annular contact (one-point contact). The contact ratio in the case of annular contact is in the range of 1.02 to 1.2, preferably in the range of 1.05 to 1.18.

The outer joint member 2 and the tripod member 5 are made of carbon steel for example, which is a mechanical structure such as S45C, S53C, S C defined in JIS G4051, and are heat-treated products obtained by subjecting portions requiring high strength and high hardness to a high-strength treatment (heat treatment) such as quenching. In the outer joint member 2, for example, the inner diameter surface of the cup-shaped portion 3 provided with the roller guide surface 4a and the like is heat treated, and the three-ball pin member 5, including the inner surface of the shaft hole 7, is heat treated over its entire surface.

As shown in fig. 2, the tripod type constant velocity universal joint 1 according to the present embodiment is a constant velocity universal joint in which the maximum operating angle θmax is set to, for example, 23 °, that is, a constant velocity universal joint in which the angle between the center axis Cj of the outer joint member 2 and the center axis Ct of the tripod type pin member 5 is 0 ° to 23 °, but an operating angle (=θ1) exceeding the maximum operating angle 0max (=23 °) can be obtained depending on the relative position in the axial direction of the outer joint member 2 with respect to the tripod type pin member 5 of the cup portion 3, as shown in fig. 4. In the illustrated example, the operating angle θ1=24°.

When the conventional tripod type constant velocity universal joint acquires the operating angle, which is described with reference to fig. 6, the phenomenon that the center axis Ct of the tripod member 103 is eccentric with respect to the center axis Cj of the outer joint member 100 and the eccentric amount thereof becomes larger as the operating angle becomes larger also occurs in the tripod type constant velocity universal joint 1 of the present embodiment. Therefore, when the constant velocity universal joint 1 attains the operating angle and the tripod member 5 is eccentric with respect to the outer joint member 2, the roller 10 approaches the outer diameter end portion (the tip end portion of the enlarged diameter portion 12 c) of the outer washer 12 mounted on the foot shaft 8 of the tripod member 5, as compared with the case where the operating angle is 0 °. Therefore, if no countermeasure is taken, as shown in fig. 4, when the constant velocity universal joint 1 becomes an operating angle θ1 exceeding the maximum operating angle θmax, the outer race 12 may be deformed by contact with both the roller 10 and the retainer ring 11.

Therefore, in the constant velocity universal joint 1 of the present embodiment, the boss portion 6 of the tripod member 5 is provided with a displacement restricting portion that restricts the angular displacement by which the operating angle is further enlarged by contacting the inner diameter surface (small inner diameter surface) 3Ba of the small diameter portion 3B of the cup portion 3 before the outer race 12 contacts both the roller 10 and the retainer ring 11 when the outer joint member 2 and the tripod member 5 are angularly displaced to the operating angle θ1 (24 ° in this case) exceeding the predetermined maximum operating angle θmax. Specifically, as shown in fig. 1B, a tapered surface 6B is provided on the outer peripheral surface 6a of the boss 6, the tapered surface gradually decreasing the outer diameter of the boss 6 toward the end surface 6c of the boss 6, and an angle α with respect to the center axis Ct (a straight line parallel to the center axis Ct) of the tripod member 5 is set equal to the maximum operating angle θmax, and a minimum diameter portion (a connecting portion of the end surface 6c of the boss 6) 6ba of the tapered surface 6B is set as the displacement restricting portion P (see an enlarged view in fig. 4).

When the tapered surface 6b is provided in the boss portion 6 of the tripod member 5, the tapered surface 6b of the boss portion 6 and the small inner diameter surface 3Ba of the cup portion 3 are disposed so as to face each other with a gap (radial gap) therebetween in a parallel state when the tripod constant velocity universal joint 1 has the maximum operating angle θmax as shown in fig. 2. From this state, when the outer joint member 2 and the tripod member 5 are further angularly displaced and the tripod constant velocity universal joint 1 obtains an operating angle θ1 exceeding the maximum operating angle θmax, as shown in fig. 4, the minimum diameter portion 6Ba (displacement restricting portion P) of the tapered surface 6b of the boss portion 6 provided in the tripod member 5 contacts the small inner diameter surface 3Ba of the cup portion 3, and further angular displacement (angular displacement exceeding the operating angle θ1) of the outer joint member 2 and the tripod member 5 is restricted.

According to the tripod constant velocity universal joint 1 of the present embodiment described above, since the boss portion 6 of the tripod member 5 is provided as a so-called angle limiter that restricts the outer joint member 2 and the tripod member 5 from being angularly displaced relative to each other beyond the predetermined operating angle (=θ1), the outer washer 12, which is an annular member, can be prevented from being deformed by contact with both the roller 10 and the retainer ring 11. The boss 6 of the tripod member 5 is a portion where the shaft member S is connected so as to be able to transmit torque, and has a sufficiently thick wall thickness as compared with the outer washer 12 made of a thin metal plate, and is high in strength and hardness by heat treatment. Therefore, even if the boss 6 (displacement restricting portion P provided) is in contact with the small inner diameter surface 3Ba of the cup-shaped portion 3, there is no possibility that the boss 6 will deform or the like.

In the present embodiment, an end portion (minimum diameter portion) 6ba of the tapered surface 6b of the outer peripheral surface 6a of the boss portion 6, which is provided at an angle α with respect to the central axis Ct of the tripod member 5 and is equal to the maximum operating angle θmax, on the end surface 6c side of the boss portion 6, is made to function as the displacement restricting portion P. According to this structure, the displacement restricting portion P (functioning as an angle limiter) can be provided only by providing the tapered surface 6b having a predetermined angle on the outer peripheral surface 6a of the boss portion 6, and therefore, damage prevention of the outer gasket 12 can be easily and inexpensively achieved.

As described above, in the tripod constant velocity universal joint 1 of the present embodiment, damage to the outer race 12 that functions as the anti-slip member of the roller 10 (and the needle roller 9) by being attached to the foot shaft 8 of the tripod member 5 can be prevented appropriately and at low cost. Therefore, the tripod type constant velocity universal joint 1 of the present embodiment has the following features: the desired workability and torque transmission performance can be stably exhibited for a long period of time without causing a special increase in cost, and the reliability is high.

The embodiments of the present invention have been described above, but the embodiments of the present invention are not limited thereto, and can be implemented in various ways within the scope not departing from the gist of the present invention. That is, the scope of the present invention is defined by the claims, and includes equivalents and modifications within the scope of the claims.

Claims (2)

1. A tripod constant velocity universal joint is provided with:

An outer joint member having a bottomed cylindrical cup portion, the cup portion having three axially extending track grooves equally spaced apart in a circumferential direction on an inner periphery thereof;

a tripod member having a cylindrical boss to which the shaft member is coupled so as to be capable of transmitting torque, and three leg shafts extending radially outward from an outer peripheral surface of the boss are provided at equal intervals in a circumferential direction;

A roller housed in the corresponding track groove in a state rotatably supported by the foot shaft via a plurality of needle rollers;

An outer washer engageable with the needle roller and the roller, and a retainer engageable with the outer washer, the outer washer being fitted to an outer peripheral surface of the foot shaft radially outward of the needle roller,

The cup-shaped portion is formed in a shape of a non-perfect circle in cross section in which three circular arc-shaped large diameter portions and three circular arc-shaped small diameter portions are alternately arranged in the circumferential direction, a roller guide surface for guiding rolling of the roller is provided on an inner surface of a connecting portion connecting the large diameter portion and the small diameter portion,

It is characterized in that the method comprises the steps of,

The boss portion is provided with a displacement restricting portion that, when the outer joint member and the tripod member are angularly displaced relative to each other beyond a predetermined maximum operating angle, is brought into contact with an inner diameter surface of the small diameter portion before the outer washer comes into contact with both the roller and the retainer ring, thereby restricting angular displacement by which the operating angle of the outer joint member and the tripod member is further enlarged.

2. The tripod type constant velocity universal joint according to claim 1, wherein,

The outer peripheral surface of the protruding portion is provided with a tapered surface having an angle with respect to a central axis of the tripod member equal to the maximum operating angle, and an end portion of the tapered surface on the end surface side of the protruding portion is defined as the displacement restricting portion.