WO2005042994A1

WO2005042994A1 - Tripod type constant velocity universal joint

Info

Publication number: WO2005042994A1
Application number: PCT/JP2004/014539
Authority: WO
Inventors: Takashi Nozaki; Yoji Sato
Original assignee: Ntn Corporation
Priority date: 2003-10-31
Filing date: 2004-09-27
Publication date: 2005-05-12
Also published as: JP2005133890A

Abstract

A tripod type constant velocity universal joint enabling a remarkable reduction in the quantity of parts and man-hour for assembly by eliminating rolling elements such as needle rollers and capable of preventing, by excellent rolling characteristics of a roller, NVH performance from being impaired. The contour shape of the outer diameter surface of the trunnion journal of the tripod type constant velocity universal joint is formed in a non-circular shape, and a contact position between the outer diameter surface of the trunnion journal and the inner diameter surface of the roller directly fitted to the outer diameter surface of the trunnion journal is shifted from a perpendicular suspended from the center of the trunnion journal to the track groove of an outer ring to a position apart a specified distance in the longitudinal direction of the track groove. The contour shape of the outer diameter surface of the trunnion journal is formed in the contour shape of the moving route of an ellipse when the ellipse is offset by a specified distance in the minor axis direction thereof or in the contour shape of the moving route of the ellipse when the ellipse is rotated by a specified angle around the center thereof.

Description

Technical field of tripod type constant velocity universal joint

The present invention relates to a sliding tripod type constant velocity universal joint used for power transmission of automobiles and various industrial machines. Background art

Constant velocity universal joints transmit torque between two non-linear rotating shafts. Sliding tripod type constant velocity natural joints are widely used in the drive system of front-engine front-wheel drive vehicles (FF vehicles). Is done. This sliding tripod type constant velocity universal joint 1 'has a tripod member 2 provided with three trunnion journals 2b protruding in the radial direction as shown in FIG. 7 (A). This tripod member 2 is connected to one shaft connected to a hub wheel in an FF vehicle. In addition, a bottomed cylindrical outer ring 4 having three track grooves 3 is coupled to the other shaft such as the output shaft of the transmission. A roller 5a rotatably fitted to the trunnion journal 2a is accommodated in the track groove 3 so as to be axially displaceable, and transmits torque between the two shafts. A rolling element such as a needle roller 6 is disposed between the trunnion journal 2 a and the roller 5. The needle rollers 6 are generally arranged in a full-roller state, and are prevented from falling off by a retaining ring 7a. The track groove 3 has a pair of circumferentially opposed roller guide surfaces 3a. The roller guide surface 3a is a concave curved surface parallel to the axial direction, and the outer diameter surface of the roller 5 is a convex curved surface adapted to the roller guide surface 3a. When the tripod-type constant velocity universal joint 1 ′ transmits torque while maintaining an operating angle, the roller 5 a and the roller guide surface 3 a have an oblique relationship. For this reason, a slip occurs between the roller guide surface 3a and the roller 5a, and an induced thrust in the axial direction due to the slide resistance and the slip occurs. These slide resistances and induced thrust adversely affect the NVH performance of the vehicle. As a sliding tripod type constant velocity universal joint having reduced slide resistance and induced thrust, for example, a low vibration type constant velocity universal joint shown in FIG. 7 (B) is known (see Patent Document 1). ). The constant velocity universal joint 1 '' has an outer diameter The inner roller 5b is slidably and swingably fitted to the runion journal 2c. An outer roller 5c is rotatably fitted to the outer diameter surface of the inner roller 5b via a needle roller 6 in a full roller state. That is, the roller rolling kit K as shown in FIG. 8 is fitted to the trunnion journal 2c of the low vibration constant velocity universal joint. The roller rolling kit K has a triple structure of the inner roller 5b, the needle rollers 6, and the outer roller 5c. The needle roller 6 is stopped by a pair of upper and lower retaining rings 7b. The outer roller 5c is accommodated in the track groove 3 so as to be axially displaceable and transmits torque, similarly to the constant velocity universal joint in FIG. 7 (A). In this low-vibration constant velocity universal joint 1 ′ ′, since the inner roller 5 b and thus the outer roller 5 c can swing with respect to the trunnion journal 2 c, the outer roller 5 c can be connected to the outer roller 5 c even at a certain operating angle. The roller guide surface 3a does not form an oblique relationship, and the generation of slide resistance and induced thrust is suppressed. Patent Document 1 Japanese Patent Application Laid-Open No. 2000-32 0 56 3 Disclosure of the Invention

In the conventional sliding tripod type constant velocity universal joints 1 'and 1' '', the roller roller kit K is composed of the needle roller 6 and the roller 5a (the inner roller 5b and the outer roller 5c for the low vibration type). However, such a conventional constant velocity universal joint has the following problems due to the use of needle rollers as rolling elements.

1. A double structure of needle rollers and rollers, or a triple structure of inner rollers, needle rollers, and outer rollers increases the number of parts, resulting in an increase in parts cost and assembly cost.

2. Needle rollers are installed in full-roller condition. However, due to the high contact surface pressure, the diameter and shaft length of the needle rollers cannot be reduced in consideration of durability, and there is a limit to compaction.

3. There is a method of improving the surface roughness of the rolling surface of the needle rollers to improve the durability, but the processing cost for improving the surface roughness increases. The present invention solves these problems. By omitting rolling elements such as needle rollers, it is possible to greatly reduce the number of parts and the number of assembling steps, and to achieve good roller rolling characteristics. An object of the present invention is to provide a tripod type constant velocity universal joint that does not impair NVH performance. In order to solve the above-mentioned problems, the present invention provides a non-circular contour of the outer diameter surface of the trunnion journal of the tri-board type constant velocity universal joint. The contact position between the radial surface and the inner diameter surface of the roller directly fitted to the outer diameter surface of the trunnion journal is determined from the perpendicular line lowered from the center of the trunnion journal to the track groove of the outer ring, and the longitudinal length of the track groove. Characterized by being moved to a position separated by a predetermined distance in the direction. In other words, in order to reduce the cost and make the tripod-type constant velocity universal joint more compact and compact, the rolling element such as a needle roller is omitted, and the inner diameter surface of the roller is directly rotatably fitted to the trunnion journal. To compensate for the lowering of the rolling characteristics of the roller due to the omission of the moving body, the contact point between the trunnion journal and the inner diameter surface of the roller must be changed from the conventional outer ring circumferential direction to the roller moving direction (the outer ring axial direction or the track groove Direction) by a predetermined distance. If the needle rollers are simply omitted, the rotation of the roller is suppressed by the sliding resistance between the trunnion journal and the inner diameter surface of the roller, which adversely affects the NVH characteristics (noise, vibration, and roughness). Therefore, in the constant velocity universal joint of the present invention, the position of the contact point between the trunnion journal and the inner diameter surface of the roller was changed in order to promote the rotation of the roller. In order to shift the contact point between the trunnion journal and the inner diameter surface of the roller, the contour of the outer diameter surface of the trunnion journal is made non-circular. Here, “non-circular” is typically the contour shape of the movement trajectory of the ellipse when the ellipse is offset by a predetermined distance in the minor axis direction, or the ellipse is defined by a predetermined angle around its center. This is the contour shape of the movement trajectory of the ellipse when rotated only by However, the “non-circular” may have any other shape as long as the point of contact between the trunnion journal and the inner diameter surface of the roller is shifted by a predetermined distance from the circumferential direction of the outer ring in the moving direction of the roller. If the cross section of the trunnion journal is the above shape, the trunnion journal will contact at two points. When reciprocating, the load ratio at the two points changes. Focusing on the contact point on the side receiving more load, the following can be considered. The mechanism for rotating the rollers will be described with reference to FIG. FIG. 3 shows a cross section of the trunnion journal 2 a and the roller 5. The symbols used in FIG. 3 are as follows.

Q: Force of the trunnion journal 2 a to push the inner diameter surface of the roller 5 vertically

F: Force that trunnion journal 2a slides roller 5 along outer ring track groove 3 (horizontal component of Q)

P: Force of trunnion journal 2a pressing roller 5 against outer ring track groove 3 (vertical component of Q)

U: Coefficient of friction between roller 5 and outer ring track groove 3 Point C: The tip of the contact ellipse e generated between the roller 5 and the outer ring track groove 3 (fulcrum when the roller rotates)

Point O: Central point of trunnion journal 2a

Point O ': Point of contact between trunnion journal 2a and roller 5 inner diameter surface

a: Shortest distance in the circumferential direction of the outer ring from point O 'to point C

b: Shortest distance in the direction of the outer ring line from point O 'to point C Here, the roller 5 moves in the direction of F when F> / P due to the force in the outer groove track groove 3 direction (joint axis direction). When sliding, F≤P, the roller is stationary. Due to the moment about the point C of the roller 5 as a fulcrum, when a F> b P, a moment in the right rotation direction acts on the roller 5, and when a F <b P, a left rotation direction acts on the roller 5. It takes moments. Table 1 below summarizes the behavior of the roller 5 described above.

【table 1】

In the upper right column of Table 1, that is, when F≤P and a F> b P, the mouthpiece 5 rolls without slipping on the outer ring track groove 3. Based on the above, the abutting position of the inner diameter surface of the collar 5 directly fitted to the outer diameter surface of the trunnion journal 2a is perpendicular from the center of the trunnion journal 2a to the track groove 3 of the outer ring. From V, it was proved that the roller 5 could be re-moved without slipping in the longitudinal direction of the track groove 3 without a rolling element by separating the roller 5 by a predetermined distance in the longitudinal direction of the track groove 3. Is done. Because the present invention is configured as described above 1. Two points of contact between the trunnion journal and the inner diameter of the roller disperse the load, lower the surface pressure, and reduce the wear of the trunnion journal.

2. By setting the abutment position between the trunnion journal and the inner diameter of the roller at a position shifted from the circumferential direction of the conventional outer ring in the direction of roller advancement, the roller can easily roll, and rolling elements such as needle rollers are omitted. Even so, the NVH characteristics required for constant velocity universal joints can be maintained.

3. The tri-board type constant velocity universal joint can be composed of three types of parts: trunnion, roller, and outer ring. The reduction in the number of parts can reduce manufacturing and assembly costs.

4. Omission of rolling elements such as needle rollers creates a space inside the joint, and this space allows a greater degree of freedom in reinforcing the strength surface, such as increasing the thickness of each part.

5. The outer diameter of the outer ring can be reduced in size and weight by reducing the dimensions of each part by utilizing the space allowance, and the accompanying cost reduction can be achieved. Brief Description of Drawings

FIG. 1 is a cross-sectional profile view of a trunnion journal of a tripod type constant velocity universal joint according to the present invention.

FIG. 2 is a sectional view of a tripod type constant velocity universal joint according to the present invention.

FIG. 3 is a cross-sectional view in the axial direction of the outer ring track groove for explaining the rolling mechanism of the roller.

FIG. 4 is a cross-sectional profile view of a trunnion journal of a tri-board type constant velocity universal joint according to a modification of the present invention.

FIGS. 5A and 5B are cross-sectional views of the trunnion journal and the rollers.

FIGS. 6A and 6B are axial sectional views of the outer ring and the roller.

FIGS. 7A and 7B are sectional views of a conventional tripod type constant velocity universal joint.

FIG. 8 is a sectional view of a roller rolling kit of a conventional tripod type constant velocity universal joint. BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 shows a cross section of the sliding tri-board type constant velocity universal joint 1 of the present invention applied to the drive system of an FF vehicle. In this tripod-type constant velocity universal joint 1, a tripboard member 2 having three trunnion journals 2a protruding in the radial direction is connected to a shaft (not shown) on the artboard side connected to the hub wheel. You. Also connected to the output shaft of the transmission A bottomed cylindrical outer ring 4 having three track grooves 3 extending in the axial direction is connected to a shaft (not shown) on the inboard side. A roller 5 directly rotatably fitted to the trunnion journal 2a is accommodated in the track groove 3 so as to be axially displaceable. The pair of guide surfaces 3a facing each other in the circumferential direction of the track groove 3 are constituted by a part of a cylindrical surface. The outer diameter surface of the roller 5 is a spherical surface conforming to the roller guide surface 3a. By the circumferential engagement between the roller 5 and the track groove 3, torque is transmitted from the transmission output shaft to the hub wheel. As shown in Fig. 1, the contour of the outer diameter surface of the trunnion journal 2a is not a circle as shown in Fig. 7 (A) or an ellipse as shown in Fig. 7 (B). This is the contour C1 of the movement trajectory of the ellipse E when offset in the short axis direction.

(Hereinafter, this contour C 1 is referred to as “offset elliptical contour C 1”). Circular inner surface of the roller 5 is fitted to the outer diameter surface of the Toranio down journal _{2 a.} Accordingly, four points P 1 to P 4 on the outer diameter surface of the trunnion journal 2 a abut on the inner diameter surface of the mouthpiece 5. Points P1 to P4 are the major axes of the ellipse E and are located in a direction offset from the ellipse by L2. Fig. 4 shows a modified example of the contour C2 of the outer diameter surface of the trunnion journal 2a, in which the ellipse E is rotated right or left by a predetermined angle around its center O (the intersection of the long axis and the short axis). This is the contour of the movement trajectory of the ellipse E at this time (hereinafter, this contour C2 is referred to as "spheroidal contour C2"). When the circular inner surface of the mouth 5 is rotatably fitted directly to the outer surface of the trunnion journal 2 a, the four points P 1 to P 4 of the outer surface of the trunnion journal 2 a are Abuts the inner diameter surface of The four points P1 to P4 overlap with the major axis L of the ellipse. As shown in FIG. 5, when the angle formed by the straight line connecting the center of the ellipse E and the point with the major axis L of the ellipse E is Θ, the value of Θ is preferably 5.8 ° shown in FIG. 5 (A). And 9 ° as shown in Fig. 5 (B) (including the angles at both ends). At 0 <5.8 °, it tends to be “stationary” in the lower right column of Table 1; In Table 1, it is easy to have “Rotating rolling slip” in the upper left column of Table 1 or “Non-rotating sliding” in the lower left column. These 5.8 ° and 9 ° were calculated from the conditions of F≤P and a F> bP. 6 (A) and 6 (B) are sectional views of a tri-board type constant velocity universal joint. The cross-sectional shape of the trunnion journal 2a of the constant velocity natural joint is an offset elliptical contour or a spheroidal elliptical contour. FIG. 6A is a cross-sectional view of a constant velocity universal joint in which the inner diameter of the roller 5 is an arc-shaped convex cross section in the axial direction cross section. The cross-sectional shape of the trunnion journal 2a is a shape obtained by offsetting or rotating the ellipse E, and the inner diameter of the roller 5 is an arc-shaped convex cross-section, so the trunnion journal 2a is located between the trunnion journal 2a and the roller 5. A relatively large gap G1 is formed in the longitudinal direction of the track groove 3. This gap G

Due to the clearance between the roller 1 and the roller 5, the re-roller 5 can move in the axial direction of the traverse journal 2a as shown by the arrow in FIG. It is possible to swing right and left. This alleviates the oblique relationship between the roller 5a and the track groove 3 when the tri-board type constant velocity universal joint rotates with the operating angle, and prevents the NVH performance from being impaired. FIG. 6 (B) is a cross-sectional view of the constant velocity natural joint in which the inner diameter of the roller 5 is cylindrical and the cross-section in the axial direction is straight. Also in this constant velocity universal joint, the trunnion journal 2 a has a cross-sectional shape obtained by offsetting or rotating the ellipse E, and a gap G 2 exists between the trunnion journal 2 a and the roller 5. Due to the presence of the upper and lower gaps (3 2 and 5), the reroller 5 can move in the axial direction of the trunnion journal 2a as shown by the arrow in FIG. —Swing and swinging in the left and right directions is possible with respect to the null 2a, so that the oblique relationship between the roller 5b and the track groove 3 when the tripod type constant velocity universal joint rotates with the operating angle Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and the technical ideas described in the claims are not limited to the embodiments. Various modifications are possible within the scope of the invention.The following lists the structures or processes that can be added as necessary to the tri-board type constant velocity universal joint of the present invention.

1. In order to stabilize the attitude of the roller 5, the outer diameter surface of the roller 5 should be spherical, and this roller 5 should be in angular contact with the track groove of the outer ring.

2. To improve the durability of the trunnion journal 2a, the outer diameter surface must be heat-treated to increase the hardness.

3. Apply a surface treatment such as thermal spraying, plating, or attaching a lubricating material to the outer diameter surface and the Z or inner diameter surface of the roller 5 for wear resistance or low friction. 4. The track groove 3 of the outer ring 4 shall be subjected to surface treatment such as thermal spraying, plating, or application of lubricating material for abrasion resistance or low friction.

5. Provide an oil groove on the outer diameter surface of the trunnion journal 2a to facilitate the intervention of lubricant. 6. Provide an oil groove on the inner diameter part and Z or outer diameter part of roller 5 to promote the intervention of lubricant.

7. Provide an oil groove in the track groove 3 of the outer ring 4 to facilitate the intervention of lubricant.

8. Of the outer diameter surface of the trunnion journal 2a, only the area that comes into contact with the inner diameter surface of the roller 5 should be ground to reduce the friction coefficient and improve durability.

Claims

Claims. The outer shape of the trunnion journal of the tripod type constant velocity universal joint is made non-circular, and the trunnion journal is directly rotatably fitted to the trunnion journal. The contact position between the roller and the inner diameter surface of the roller is set at a position separated by a predetermined distance in the longitudinal direction of the track groove from a perpendicular line lowered from the center of the trunnion journal to the track groove of the outer ring. Reboard type constant velocity universal joint.

2. The tripod according to claim 1, wherein the contour shape of the outer diameter surface of the trunnion journal is the contour shape of the movement locus of the ellipse when the ellipse is offset by a predetermined distance in the minor axis direction. One-DO type constant velocity universal joint.

3. The tri-board type according to claim 1, wherein a contour shape of an outer diameter surface of the trunnion journal is a contour shape of a movement locus of the ellipse when the ellipse is rotated around a center thereof by a predetermined angle. Constant velocity universal joint.

4. A predetermined gap is formed between the outer diameter surface of the trunnion journal and the inner diameter surface of the roller in the longitudinal direction of the track groove, to allow the roller to swing. Or the tripod constant velocity universal joint described in 3.

5. The inner diameter surface shape of the roller is an arc-shaped convex shape in which the inner diameter at the center in the axial direction is smaller than the inner diameter at both ends in the axial direction of the trunnion journal. Tripod type constant velocity universal joint.

6. The tripod constant velocity universal joint according to claim 2, wherein an outer diameter surface of the roller is a spherical surface, and the roller is an angular contact with a track groove of the outer ring.

7. The tripod according to claim 1, wherein the outer diameter surface of the trunnion journal is subjected to a surface treatment such as thermal spraying, plating, or application of a lubricating material for abrasion resistance or low friction. One-DO type constant velocity universal joint.

8. The tripod constant velocity universal joint according to claim 1, wherein a heat treatment for increasing hardness is performed on an outer diameter surface of the trunnion journal.

9. The tripod according to claim 1, wherein an outer diameter surface of the roller is subjected to a surface treatment such as thermal spraying, plating, or application of a lubricating material for reducing abrasion resistance or friction. Type constant velocity universal joint.

10. The tripod according to claim 1, wherein the inner diameter portion of the roller has been subjected to a surface treatment such as thermal spraying, plating, or application of a lubricating material for abrasion resistance or low friction. Type constant velocity universal joint.

11. The track according to claim 1, wherein the track groove of the outer ring is subjected to a surface treatment such as thermal spraying, plating, or attaching a lubricating material for abrasion resistance or low friction. Reboard type constant velocity universal joint.

12. The tripod constant velocity universal joint according to claim 1, wherein an oil groove is provided on an outer diameter surface of the trunnion journal to facilitate the intervention of a lubricant.

13. The tripod constant velocity universal joint according to claim 1, wherein an oil groove is provided at an inner diameter portion and a Z or outer diameter portion of the roller to facilitate the intervention of a lubricant.

14. The tripod constant velocity universal joint according to claim 1, characterized in that an oil groove is provided in the track groove of the outer ring to facilitate the intervention of a lubricant.

15. The tripod constant velocity universal joint according to claim 1, wherein only a region of the outer diameter surface of the trunnion journal that contacts the inner diameter surface of the roller is ground.

16. The abutment position between the outer diameter surface of the trunnion journal and the inner diameter surface of the roller is determined in the circumferential direction of the roller based on a perpendicular drawn from the center of the trunnion journal to the track groove of the outer ring. 2. The tripod-type constant velocity universal joint according to claim 1, wherein the joint is separated by 8 ° or more and 9 ° or less.