JP2000161378A - Constant velocity universal joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To much more lessen inductive thrust caused when rotating torque is transmitted while an operating angle is being formed between an outside joint member and a tripord member, and thereby provide a tripord type constant velocity universal joint much less in oscillation. SOLUTION: A center region in the rolling surface 6a of a needle shaped roller 6 interposed between the outer circumferential surface 5a of a leg axis and the inner circumferential surface 7a of an internal roller, is formed into a cylindrical part 6a1 parallel with an axial line 6x, and each of both the end regions is formed into a crowning part 6a2 gradually dropped with a little curvature toward both the end surfaces 6b. The rolling surface 6a comes in contact with the outer circumferential surface 5a of the leg axis, and the inner curcumferential surface 7a of the internal roller in the region of the cylindrical part 6a1, and the length (contact length) L1 in the axial direction of the cylindrical part 6a1, is set to be L1/L<=0.7 with respect to the whole length L of the needle shaped roller 6. In addition, the quantity δ of drop at the position of (L-L1)/4 from the end surface 6b of the needle shaped roller 6 is in a range of 1 μm<=δ<=15 μm.

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 used for a power transmission device of an automobile or various industrial machines, and more particularly to a tripod type constant velocity universal joint.

[0002]

2. Description of the Related Art A tripod type constant velocity universal joint having a structure shown in FIGS. 6 and 7, for example, is known. In this constant velocity universal joint, three track grooves 22 are formed in the inner peripheral portion in the axial direction, and an outer joint member 21 having an axial roller guide surface 22a on both sides of each track groove 22 is provided. A tripod member 24 having three protruding leg shafts 25, and a roller 20 rotatably mounted on a cylindrical outer peripheral surface of each leg shaft 25 via a needle roller 26.
It is composed of Each roller 20 of tripod member 24
Are accommodated in the roller guide surfaces 22a of the track grooves 22 of the outer joint member 21, respectively. As each roller 20 rolls on the roller guide surface 22a while rotating about the axis of the leg shaft 25, relative axial displacement and angular displacement between the outer joint member 21 and the tripod member 24 are smoothly performed. At the same time, when the outer joint member 21 and the tripod member 24 transmit a rotational torque while maintaining a predetermined operating angle, a change in the phase in the rotational direction causes a change in the phase of each leg shaft 25 with respect to the roller guide surface 22a. Axial displacement is smoothly guided.

In practice, however, as shown in FIGS. 8 and 9, when the outer joint member 21 and the tripod member 24 transmit the rotational torque while maintaining the operating angle θ, the leg shaft 25
As a result, the respective rollers 20 and the roller guide surface 22a are obliquely intersected with each other, and the smooth rolling of each roller 20 is hindered. That is, the roller 2
8, the roller guide surface 22a has an arcuate cross section and extends in parallel with the axis of the outer joint member 21. Therefore, the roller 20 moves axially on the roller guide surface 22a while rotating in a state of twisting with respect to the leg shaft 25. For this reason, a slip occurs at a contact portion between the outer peripheral surface of the roller 20 and the roller guide surface 22a, so that the frictional resistance (sliding resistance) increases, and at the same time, the needle roller 26 interposed between the roller 20 and the leg shaft 25 has Eccentric load is applied,
The occurrence of skew or edge load hinders the smooth rolling of the needle roller 26, and the roller 20 cannot rotate smoothly with respect to the leg shaft 25. The increase in sliding resistance due to the inclination of the roller 20 and the impairment of the rolling property of the needle roller 26 due to skew and edge load increase the induced thrust in this type of joint, and are related to the sliding resistance. This is considered to be the cause of idling vibration accompanying the vibration transmission. Induced thrust and slide resistance cause vibrations at the joints.For example, in a vehicle power transmission device, if the induced thrust or slide resistance at the joints is large, these are transmitted to the vehicle body via the power transmission path, and the vibration of the vehicle body There is a problem that passengers feel uncomfortable by increasing noise and noise.

In view of the above circumstances, a constant velocity universal joint having the structure shown in FIGS. 10 and 11 has been proposed in order to eliminate the oblique state between the roller and the roller guide surface and to reduce the induced thrust (Japanese Patent Application Publication No. HEI-Hei). No. 3-1529), which contributes to reduction of vibration and noise. This constant velocity universal joint includes a roller mounted on the leg shaft 25 of the tripod member 24 and an outer roller 2.
3 and two rollers of the inner roller 27, and allows the inclination between the outer roller 23 and the leg shaft 25 (and the inner roller 27) (inclination mechanism). Outer roller 23
Contacts the roller guide surface 22a and rolls on the roller guide surface 22a. The inner roller 27 has a spherical outer peripheral surface 27b, and is fitted to the cylindrical inner peripheral surface 23a of the outer roller 23. The inner peripheral surface of the inner roller 27 is fitted to the cylindrical outer peripheral surface of the leg shaft 25 via the needle rollers 26.

As shown in FIG. 12, when the outer joint member 21 and the tripod member 24 transmit the rotational torque while maintaining the operating angle θ, the inner roller 2
7 is inclined with respect to the roller guide surface 22a,
Since the inclination of the roller 3 with respect to the leg shaft 25 and the inner roller 27 is allowed, the roller 3 can roll on the roller guide surface 22a while maintaining a parallel posture with respect to the roller guide surface 22a. As a result, smooth rolling of the outer roller 23 is secured, sliding resistance with the roller guide surface 22a is reduced, and induced thrust is suppressed.

[0006]

As described above, FIG.
And the constant velocity universal joint shown in FIG. 11 achieves a reduction in the induced thrust as compared with the earlier one, but in order to further reduce the induced thrust and slide resistance in this kind of constant velocity universal joint, It is important that the rollers rotate more smoothly with respect to the leg axis.

Accordingly, the present invention is to improve the rolling stability of the needle roller, thereby allowing the roller to rotate more smoothly with respect to the leg shaft, thereby reducing the induced thrust and slide resistance in this kind of constant velocity universal joint. It is intended to further reduce it.

[0008]

In order to achieve the above object, according to the present invention, three axial track grooves are formed in an inner peripheral portion, and axial roller guide surfaces are provided on both sides of each track groove. Outer joint member having a radially projecting 3
A tripod member having a plurality of leg shafts, and a roller rotatably mounted on an outer peripheral surface of each leg shaft via a needle roller, respectively, wherein the roller of the tripod member is adapted to a roller guide surface of an outer joint member. In the constant velocity universal joint, the contact length (L1) between the rolling surface of the needle roller and the outer peripheral surface of the leg shaft is:
Provided is a configuration in which crowning is performed on the entire length (L) of the needle roller so that L1 / L ≦ 0.7.

By performing the above-mentioned crowning on the rolling surface of the needle roller, the occurrence of edge load due to the skew of the needle roller is suppressed, and the rolling stability of the needle roller is increased.
Therefore, the roller can move axially on the roller guide surface while smoothly rotating with respect to the leg axis, thereby reducing induced thrust and slide resistance.

In the above configuration, a more preferable result can be obtained by setting the drop amount δ of the crowning at the position (L−L1) / 4 from the end face of the needle roller in the range of 1 μm ≦ δ ≦ 15 μm.

An outer roller guided by a roller guide surface and an inner roller fitted to the inner peripheral surface of the outer roller and rotatably mounted on the outer peripheral surface of the leg shaft via a needle roller. And a roller. By providing such an inclining mechanism, the parallel posture of the outer roller with respect to the roller guide surface can be maintained. The inner peripheral surface of the outer roller has a cylindrical surface, the outer peripheral surface of the inner roller has a spherical surface, or the inner peripheral surface of the outer roller has a conical surface whose diameter is reduced toward the tip of the leg shaft, and the outer peripheral surface of the inner roller has It can be a spherical surface. In the latter case, a load component directed toward the tip of the leg shaft is generated at the contact portion between the inner peripheral surface of the outer roller and the outer peripheral surface of the inner roller, and acts in the direction of pushing the outer roller toward the distal end of the leg shaft. The effect of stabilizing the attitude of the roller is further enhanced.

[0012] Both end surfaces of the needle roller may be arcuate surfaces. Accordingly, the frictional force between the needle roller and the member that prevents the needle roller from coming off in the axial direction is reduced, and the rolling stability of the needle roller is further improved.

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
This will be described with reference to FIG. 1 to 4 show the state when the operating angle of the joint is 0 °.

The constant velocity universal joint according to the first embodiment shown in FIG. 1 has an outer joint member 1 connected to one of two shafts to be connected.
And a tripod member 4 coupled to the other. The outer joint member 1 has a generally cup-like appearance, and three track grooves 2 extending in the axial direction are formed at evenly distributed positions on the inner peripheral portion. The tripod member 4 has three leg shafts 5 protruding in the radial direction at circumferentially equidistant positions. The inner roller 7 is rotatably fitted to the cylindrical outer peripheral surface 5a of the leg shaft 5 via a plurality of needle rollers 6, and the outer roller 3 is rotatably fitted to the outer diameter side thereof. I have.

As shown in FIG. 2 in an enlarged manner, the needle roller 6 and the inner roller 7 are locked at one end thereof by a retaining ring 8 and a retaining ring 9 mounted on the tip of the leg shaft 5, and The other end is locked by a washer 10 attached to the base end of the leg shaft 5, and the movement of the leg shaft 5 in the axial direction is restricted. Actually, there is a slight axial clearance between one end of the needle roller 6 and the inner roller 7 and the retaining ring 8, and between the other end of the needle roller 6 and the inner roller 7 and the washer 10, respectively. Further, there is a slight radial clearance between the outer peripheral surface 5 a of the leg shaft 5 and the inner peripheral surface 7 a of the inner roller 7 and the needle roller 6. Inner peripheral surface 7 of inner roller 7
a is a cylindrical surface, and the outer peripheral surface 7b is a convex spherical surface. In this embodiment, the generatrix of the outer peripheral surface 7b is a circular arc centered on the predetermined amount the point P _2, which are offset radially outward from the radially center P ₁ of the inner roller 7.

The outer roller 3 has an outer peripheral surface 7 of the inner roller 7.
b. In this embodiment, the outer roller 3
The inner peripheral surface 3a is a cylindrical surface, and is in line contact with the outer peripheral surface 7b of the inner roller 7. Accordingly, relative tilt displacement between the outer roller 3 and the inner roller 7 is allowed, and a mechanism that allows the relative tilt between the two is the tilt mechanism.

The outer peripheral surface 3b of the outer roller 3 is composed of a first surface portion 3b1 at both ends and a second surface portion 3b2 at the center between the first surface portions 3b1. In this embodiment, the first surface portions 3b1 at both ends are convex spherical surfaces, and the second surface portions 3b2 are cylindrical surfaces. First surface portions 3b1 at both ends
Busbars, respectively, an arc centered on the P ₃ points which is further offset to the outer diameter side than the point P _2.

The track groove 2 of the outer joint member 1 has roller guide surfaces 2a on both sides in the rotation direction. In this embodiment, of the roller guide surface 2a, the surface portion 2a1 that contacts the first surface portion 3b1 of the outer roller 3 is an arc-shaped cross section, and the surface portion 2a2 that contacts the second surface portion 3b2 of the outer roller 3 is flat. It is shaped like a face. As shown exaggeratedly in FIG. 3, the curvature of the surface portion 2a1 is slightly larger than the curvature of the first surface portion 3b1, whereby the first surface portion 3b1 and the surface portion 2a1 make angular contact with each other at a contact angle φ.
The contact angle φ can be set to, for example, 30 °.

The first surface portions 3b1 provided at both ends of the outer peripheral surface 3b of the outer roller 3 are
By making angular contact with the surface portion 2a1 of the outer joint member a at a contact angle φ, the inclination of the outer roller 3 in the longitudinal sectional direction of the outer joint member 1 (the inclination in the front-rear direction) is suppressed. At the same time, the cylindrical second surface portion 3b2 provided at the center of the outer peripheral surface 3b of the outer roller 3 is
By contacting the flat surface portion 2a2, the inclination (lateral inclination) of the outer roller 3 in the cross-sectional direction of the outer joint member 1 is suppressed. Therefore, when the outer joint member 1 and the tripod member 4 transmit a rotational torque while maintaining an operating angle, the inclination (sway) of the outer roller 3 is suppressed, and the outer roller 3 is always parallel to the roller guide surface 2a. It is possible to move in the axial direction while maintaining the posture.
Thereby, the sliding resistance of the contact portion between the outer roller 3 and the roller guide surface 2a is reduced, and the induced thrust is reduced.

FIG. 5 shows the needle roller 6 interposed between the outer peripheral surface 5a of the leg shaft 5 and the inner peripheral surface 7a of the inner roller 7. The center region of the rolling surface 6a of the needle roller 6 is a cylindrical portion 6a1 parallel to the axis 6x, and both end regions are crowned portions 6 gradually dropped with slight curvature toward both end surfaces 6b.
a2. Cylindrical part 6a1 and crowning part 6a
2 is smoothly continuous. Both end faces 6b of the needle roller 6
Is an arc surface.

The rolling surface 6a of the needle roller 6 has a cylindrical portion 6a1.
In the region of (1), the outer peripheral surface 5a of the leg shaft 5 and the inner peripheral surface 7a of the inner roller 7 are in contact with each other, and the axial length (contact length) L1 of the cylindrical portion 6a1 is larger than the total length L of the needle roller 6. L1 / L ≦
It is set to 0.7. Although not shown, L1
In the case of = 0, it is a state in which so-called full crowning has been applied to the rolling surface 6a, and L1 / L ≦ 0.7 includes this state. Further, the crowning portion 6a2 is not limited to one having a curvature, and may be so-called cut crowning (linear crowning). Further, the boundary between the cylindrical portion 6a1 and the crowning portion 6a2 may be smoothly continued on the radius surface.

The drop amount of the crowning portion 6a2 is not particularly limited as long as the intended effect of the present invention can be obtained. However, as shown in FIG. 5B, (L-L1) / (L-L1) / The drop amount δ at position 4 is 1μ
It is preferable that m ≦ δ ≦ 15 μm.

By providing the above-mentioned crowning portion 6a2 on the rolling surface 6a of the needle roller 6, the rolling surface 6a of the needle roller 6, the outer peripheral surface 5a of the leg shaft 5, and the inner peripheral surface of the inner roller 7 are provided. The generation of the edge load at the contact portion with 7a is suppressed, and stable rolling of the needle roller 6 is ensured. Thereby, rotation of the inner roller 7 and the outer roller 3 with respect to the leg shaft 5 is performed smoothly, and induced thrust and slide resistance are reduced.

As described above, the constant velocity universal joint of this embodiment has the effect of reducing the induced thrust by stabilizing the attitude of the outer roller 3 and the effect of reducing the induced thrust and slide resistance by improving the rolling stability of the needle roller 6. Excellent low vibration characteristics are exhibited in combination with the reduction effect.

In the constant velocity universal joint according to the second embodiment shown in FIG. 4, the inner peripheral surface 3a of the outer roller 3 has a conical surface whose diameter decreases toward the tip end of the leg shaft 5 (inclined). Angle α).
In the configuration of this embodiment, a load component directed toward the distal end of the leg shaft is generated at the contact portion between the inner peripheral surface 3a of the outer roller 3 and the outer peripheral surface 7b of the inner roller 7, and the outer roller 3 is moved toward the distal end of the leg shaft. Since it acts in the pushing direction, the above-described effect of stabilizing the posture of the outer roller 3 is further enhanced, and the induced thrust is more effectively reduced. Note that the inclination angle (cone angle) of the inner peripheral surface 3a of the outer roller 3 is as small as, for example, 0.1 ° to 3 °. Other configurations are the same as those of the first embodiment, and have the same functions and effects.

The present invention can be similarly applied to a constant velocity universal joint having a configuration in which one roller is mounted on a leg shaft via a needle roller as shown in FIGS.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Cylindrical portion 6a on rolling surface 6a of needle roller 6
1 in the axial direction (contact length) L1 with respect to the total length L.
/L≦0.7, the effect of reducing induced thrust, and (L) from the end face 6b of the crowning portion 6a2.
−L1) / 4, the drop amount δ at 1 μm ≦ δ
A test was conducted to confirm the effect of reducing the induced thrust by setting ≦ 15 μm. The test was performed using (L1 / L) and
Are set as shown in Table 1 below, and seven types of needle rollers are manufactured, each of which is incorporated into a constant velocity universal joint having the configuration shown in FIG. 4 to manufacture seven types of test joints. The measurement was performed by measuring the induced thrust while rotating under a predetermined operating angle, load, and rotation speed. In the column of induced thrust in Table 1, the average value of the induced thrust measured in this way was compared with the evaluation reference value. Indicates that the induced thrust reduction effect was remarkable, and ○ indicates that the effect of reducing the induced thrust was remarkable.

[0028]

[Table 1]

From the results shown in Table 1, even when either L1 / L ≦ 0.7 or 1 μm ≦ δ ≦ 15 μm was satisfied, a favorable result was obtained (△). It was confirmed that a remarkable effect of reducing the thrust was obtained (）).

[0030]

As described above, according to the present invention,
The length of contact between the rolling surface of the needle roller and the outer peripheral surface of the leg shaft (L
1) is L1 / L ≦ to the total length (L) of the needle rollers.
Since the crowning of 0.7 is performed, the rolling stability of the needle roller is improved, and the induced thrust and slide resistance are reduced by the roller rotating smoothly with respect to the leg axis. This reduction effect can be made more remarkable by setting the drop amount δ of the crowning at the position (L−L1) / 4 from the end face of the needle roller in the range of 1 μm ≦ δ ≦ 15 μm. it can. Therefore, the constant velocity universal joint of the present invention has excellent vibration characteristics.
This can contribute to further reduction of noise.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a constant velocity universal joint according to a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a main part of FIG.

FIG. 3 is an enlarged sectional view of a main part of FIG. 2;

FIG. 4 is a cross-sectional view of a constant velocity universal joint according to a second embodiment of the present invention.

FIG. 5 is a front view (FIG. A) of a needle roller incorporated in the constant velocity universal joint of the first embodiment and the second embodiment, and an enlarged front view of an end face region (FIG. B).

FIG. 6 is a longitudinal sectional view of a conventional constant velocity universal joint.

FIG. 7 is a cross-sectional view of FIG.

8 is a longitudinal sectional view showing a state where the conventional joint shown in FIGS. 6 and 7 takes an operating angle.

FIG. 9 is a perspective view showing a relationship between a roller and a roller guide surface when an operation angle is set.

FIG. 10 is a longitudinal sectional view of another conventional constant velocity universal joint.

FIG. 11 is a cross-sectional view of FIG.

12 is a longitudinal sectional view showing a state where the conventional joint shown in FIGS. 10 and 11 takes an operating angle.

[Explanation of symbols]

 Reference Signs List 1 outer joint member 2 track groove 2a roller guide surface 3 roller (outer roller) 3a inner peripheral surface 3b outer peripheral surface 4 tripod member 5 leg shaft 5a outer peripheral surface 6 needle roller 6a rolling surface 6a2 crowning portion 6b end surface 7 inner roller 7a Inner surface 7b Outer surface

 ────────────────────────────────────────────────── ─── Continued on front page (72) Inventor Masayuki Kuroda 1-37-1 Kyomachibori, Nishi-ku, Osaka-shi, Osaka Inside NTN Corporation (72) Inventor Kenji Terada 1578 Higashikaizuka, Iwata-shi, Shizuoka Prefecture NTN Corporation

Claims (6)

[Claims] An outer joint member having three axial track grooves formed on an inner peripheral portion thereof and having an axial roller guide surface on both sides of each track groove, and a radially projecting three groove groove.
A tripod member having a plurality of leg shafts, and a roller rotatably mounted on an outer peripheral surface of each leg shaft via a needle roller, respectively, wherein the roller of the tripod member is adapted to a roller guide surface of an outer joint member. In the constant velocity universal joint, the contact length (L1) between the rolling surface of the needle roller and the outer peripheral surface of the leg shaft is L with respect to the total length (L) of the needle roller.
A constant velocity universal joint characterized by being crowned so that 1 / L ≦ 0.7. 2. From the end face of the needle roller, (L-L1) /
The drop amount δ of the crowning at the position 4 is
2. The constant velocity universal joint according to claim 1, wherein 1 μm ≦ δ ≦ 15 μm. 3. The roller is fitted on an outer roller guided by the roller guide surface and an inner peripheral surface of the outer roller, and is rotatable on an outer peripheral surface of the leg shaft via a needle roller. 2. The constant velocity universal joint according to claim 1, wherein the constant velocity universal joint is constituted by an inner roller mounted on the inner roller. 4. An inner peripheral surface of the outer roller is a cylindrical surface,
The constant velocity universal joint according to claim 3, wherein the outer peripheral surface of the inner roller is a spherical surface. 5. The constant velocity universal joint according to claim 3, wherein the inner peripheral surface of the outer roller is a conical surface whose diameter decreases toward the tip end side of the leg shaft, and the outer peripheral surface of the inner roller is a spherical surface. 6. The constant velocity universal joint according to claim 1, wherein both end faces of the needle roller are arc-shaped faces.