JPH09151952A - Trunnion member for triboard type constant velocity universal joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the thrust induced when a joint transmits a rotation torque while taking an operating angle by promoting the proper rolling of a needle roller and ensuring the smooth rotation of a spherical roller. SOLUTION: A plurality of needle rollers 3 are arranged on the outer circumferential surface 2a1 of the leg shaft 2a of a trunnion member 2 in such a manner as to be capable of rolling, and a spherical roller 41 is rotatably fitted thereto through the needle rollers 3. The whole axial length H of the spherical. roller 41 is set substantially equal to the whole axial length L of the needle roller 3, but both the bore end parts of the spherical roller 41 are cut by tapered cut parts 41c, 41d, respectively, so that the axial length (h) of a cylindrical contact surface 41a is smaller than the axial length L' of a rolling surface 3a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tripod type constant velocity universal joint used for power transmission in automobiles and various industrial machines.

[0002]

5 and 6 show the most basic structure of a tripod type constant velocity universal joint. This tripod type constant velocity universal joint (TJ) has three leg shafts 2a
A trunnion member 2 provided in a radial direction at intervals of a degree in the circumferential direction, and three leg shafts 2a of the trunnion member 2 via a needle roller 3 and a spherical roller 4 to a track groove 1a.
And an outer ring 1 that rotates integrally with each other and has a feature of transmitting rotational torque at a constant speed even when the two shafts have an operating angle and permitting relative displacement in the axial direction. .

The outer ring 1 has a substantially cylindrical cup shape with one end open and the other end closed, a first shaft 5 is integrally provided on the other end, and three pairs of axial track grooves 1a are formed on the inner circumference. It is formed at intervals of 120 degrees. The cross-section of the track groove 1a is a concave spherical surface (the generatrix is a concave arc).

The trunnion member 2 is fitted in a serration portion (or spline portion) 6a formed at one end of the second shaft 6, and is retained and retained on both axial sides between the step portion 6b and the clip 6c. . A plurality of needle rollers 3 are rotatably arranged on the outer diameter surface 2a1 of the leg shaft 2a of the trunnion member 2, and a spherical roller 4 is rotatably fitted through the needle rollers 3. The outer diameter surface 2a1 of the leg shaft 2a is a cylindrical surface. The inner diameter surface 4a of the spherical roller 4 is a cylindrical surface, and the outer diameter surface 4b is a convex spherical surface (the generatrix is a convex arc). Spherical roller 4
The outer diameter surface 4b of is fitted into the track groove 1a.

The torque is transmitted between the outer ring 1 and the trunnion member 2 by the contact portion between the track groove 1a and the outer diameter surface 4b of the spherical roller 4, the inner diameter surface 4a of the spherical roller 4 and the rolling surface 3a of the needle roller 3. And the contact surface between the rolling surface 3a of the needle roller 3 and the outer diameter surface 2a1 of the leg shaft 2a.

In the above structure, the axial length of the cylindrical inner diameter surface 4a of the spherical roller 4 and the axial length of the rolling surface 3a of the needle roller 3 are substantially the same.

[0007]

In the tripod type constant velocity universal joint of this type, if the induced thrust is large when the rotational torque is transmitted while keeping the operating angle, the vibration characteristics of the joint are adversely affected. Various factors can be considered as a factor for generating the induced thrust, and as one of the factors, the spherical roller 4 at the time of applying the operating angle as shown in FIG.
Displacement can be mentioned. That is, the plurality of needle rollers 3 are attached to the axle 2a by the washers 7 attached to the axle 2a.
Although the displacement of the spherical roller 4 is restricted, the spherical roller 4
Since such a displacement is allowed, the spherical roller 4 is (3/2) PCR {(1 / cos θ) -1} is displaced by (1/2) PCR {(1 / cos θ) -1} to the proximal end side of the leg shaft 2a. Then, a partial area of the cylindrical inner diameter surface 4a of the spherical roller 4 deviates from the rolling surface 3a of the needle roller 3, a concentrated load acts on the end portion of the needle roller 3, and the needle roller 3 is skewed (needle roller 3). This causes a phenomenon in which the roller 3 tilts with respect to the regular rotation axis. Then, by causing the needle roller 3 to skew,
The proper rolling is hindered, which hinders the smooth rotation of the spherical roller 4. This contributes to the increase in induced thrust.

By the way, the tripod type constant velocity universal joint has a structure in which the displacement of the spherical roller fitted to the outer diameter surface of the leg shaft of the trunnion member via a plurality of needle rollers is restricted in addition to the above-mentioned structure. There are also things. For example, the tripod type constant velocity universal joint shown in FIG. 7 includes an inner spherical roller 4 ′ rotatably fitted to the outer diameter surface 2a1 of the leg shaft 2a of the trunnion member 2 via a plurality of needle rollers 3 and an inner spherical surface. The outer spherical roller 4 which is rotatably fitted to the spherical outer diameter surface 4'b of the roller 4'and whose spherical outer diameter surface 4 "b is fitted to the spherical track groove 1a of the outer ring 1. The inner spherical surface is formed by a pair of washers 8 and 9 attached to the distal end portion and the proximal end portion of the leg shaft 2a and a retaining ring 10 fitted to the tip end portion of the leg shaft 2a. The displacement of the leg shaft 2a of the roller 4'in the axial direction is restricted.

In the tripod type constant velocity universal joint of this type, unlike the above-mentioned structure, the entire area of the cylindrical inner diameter surface 4'a of the inner spherical roller 4'is always in contact with the rolling surface 3a of the needle roller 3. To do. However, when the inner spherical roller 4'has a moment load in the axial direction of the outer ring, the inner spherical surface 4 '
edge contact occurs at the contact portion between a and the rolling surface 3a of the needle roller 3 and at the contact portion between the rolling surface 3a and the outer diameter surface 2a1 of the leg shaft 2a, and the edge load causes the needle roller 3 to skew. And may also contribute to increasing the induced thrust.

In addition, it is also known that the displacement of the spherical roller is restricted by a washer attached to the leg shaft, and the track groove of the outer ring is a flat surface extending in the axial direction (for example, Japanese Utility Model Laid-Open No. 4-84292). .

The present invention prevents the skew of the needle roller due to the unbalanced load (concentrated load, edge load) as described above, and promotes the proper rolling of the needle roller, thereby ensuring the smooth rotation of the spherical roller, Therefore, it is intended to further reduce the induced thrust.

[0012]

A tripod type constant velocity universal joint according to claim 1 has three leg shafts projecting in a radial direction and a plurality of roll shafts rotatably arranged on an outer diameter surface of the leg shaft. Of the needle roller and the outer diameter surface of the leg shaft are rotatably fitted through the needle roller, and the inner diameter of the needle roller has a cylindrical contact surface that comes into contact with the rolling surface of the needle roller. In a trunnion member of a tripod type constant velocity universal joint having a spherical roller that is allowed to be displaced to, the axial length of the cylindrical contact surface of the spherical roller is smaller than the axial length of the rolling surface of the needle roller. However, when the spherical roller is displaced by the maximum amount in either the tip end side or the base end side of the stem, the entire area of the cylindrical contact surface of the spherical roller contacts the rolling surface of the needle roller. It is what

The tripod type constant velocity universal joint according to claim 2 is
Three leg shafts protruding in the radial direction, a plurality of needle rollers rotatably arranged on the outer diameter surface of the leg shaft, and rotatably fitted on the outer diameter surface of the leg shaft via needle rollers. A trunnion member for a tripod type constant velocity universal joint, which has a cylindrical contact surface that is in contact with the rolling surface of the needle roller and that has a spherical roller whose displacement in the axial direction of the leg shaft is restricted. In the above, the axial length of the cylindrical contact surface of the spherical roller is made smaller than the axial length of the rolling surface of the needle roller.

As a means for making the axial length of the cylindrical contact surface of the spherical roller smaller than the axial length of the rolling surface of the needle roller, a construction is adopted in which both inner diameter end portions of the spherical roller are cut by cut portions. be able to.

The axial length of the cylindrical contact surface of the spherical roller is 40 relative to the axial length of the rolling surface of the needle roller.
-60% is most effective in reducing the induced thrust.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment in which the present invention is applied to a tripod type constant velocity trunnion member 2 shown in FIGS. 5 and 6 will be described below.

As shown in FIG. 1, a plurality of needle rollers 3 are rotatably arranged on an outer diameter surface 2a1 of a leg shaft 2a of a trunnion member 2, and a spherical roller 4 is interposed via the needle rollers 3.
1 is rotatably fitted. The plurality of needle rollers 3 are composed of a pair of washers 7 and 7 ′ attached to the distal end portion and the proximal end portion of the leg shaft 2 a, and a snap ring 11 fitted to the tip end portion of the leg shaft 2 a. The displacement in the direction is restricted, and the spherical roller 41 is allowed to rotate smoothly by rolling on the outer diameter surface 2a1 of the leg shaft 2a. The spherical roller 41 includes a spherical outer diameter surface 41b fitted in a track groove of an outer ring (not shown), and a cylindrical contact surface 41a in line contact with the rolling surface 3a of the needle roller 3, and the leg shaft 2a. A predetermined amount of displacement in the axial direction is allowed.

The total axial length H of the spherical roller 41 is about the same as the total axial length L of the needle roller 3, but in this embodiment, both inner diameter end portions of the spherical roller 41 are tapered. The axial length h of the cylindrical contact surface 41a is cut by the cut portions 41c and 41d, and the axial length L ′ of the rolling surface 3a (from the total axial length L to the chamfering and crowning of both end surfaces). Minus the length). The extent to which the axial length h of the cylindrical contact surface 41a is made smaller than the axial length L'of the rolling surface 3a depends on whether the spherical roller 41 is on the tip end side or the base end side of the leg shaft 2a. Even when the maximum amount of displacement in the direction, the entire area of the cylindrical contact surface 41a is in contact with the rolling surface 3a (the cylindrical contact surface 41a does not disengage from the rolling surface 3a) as a reference, Within the range where such a state is obtained, it is appropriately set according to the usage conditions and the like.

As shown in FIG. 2, the cut amount (axial length) h1 of the cut portion 41c and the cut amount (axial length) h2 of the cut portion 41d may be equal (h1 = h).
2), they may not be equal (h1 ≠ h2).

Further, the shape of the cut portions 41c and 41d is not limited to the above-mentioned tapered shape, but may be a step shape as shown in FIG. 3, an arc shape, or other shapes.

In the embodiment described above, in order to prevent edge loading at the contact portion between the cylindrical contact surface 41a and the rolling surface 3a, rounded chamfers are formed at both ends (both corners) of the cylindrical contact surface 41a. It is good to apply.

The embodiment shown in FIG. 4 uses a spherical roller 4 having the same construction as the conventional one, and the axial length L of the needle roller 3 is L.
By increasing the axial length of the spherical roller 4 so that the axial length h of the cylindrical inner diameter surface (cylindrical contact surface) 4a of the spherical roller 4 is smaller than the axial length L'of the rolling surface 3a. Is.

The product of the embodiment shown in FIG. 1 (h / L '= 0.
5, two kinds of h / L ′ = 0.25) and the conventional products shown in FIGS. 5 and 6 were used to measure the induced thrust. The results are summarized in FIG. In the figure, line A is the embodiment product A (h / L '= 0.5), line B is the embodiment product B (h / L' = 0.25), and line C is the conventional product. Is shown.

As shown in the figure, the product A of the embodiment was found to have a large effect of reducing the induced thrust as compared with the conventional product C. On the other hand, in the case of the embodiment product B, good results were obtained in the region of the working angle θ ≦ θ1, but in the region of the working angle θ> θ1, the increase gradient of the induced thrust accompanying the increase of the working angle θ was large, and the working angle θ In the region of ≧ θ2, the induced thrust was larger than that of the conventional product C. This is the cylindrical contact surface 41a and the rolling surface 3
It is considered that this is due to the influence of the increase in surface pressure at the contact portion with a. As a result of measuring the induced thrust by changing (h / L ') to various values, it was found that the best result was obtained when (h / L') was set to about 0.4 to 0.6. did.

The present invention is not limited to the tripod type constant velocity universal joint (TJ) having the construction shown in FIGS. 5 and 6, but the trunnion member 2 of the tripod type constant velocity universal joint (FTJ) having the construction shown in FIG. (Inner spherical roller 4 ′ and needle roller 3), and other trunnion members such as tripod type constant velocity universal joints having the configurations shown in FIGS. 9 to 11 can be similarly applied.

[0026]

As described above, according to the present invention,
Proper rolling of the needle roller is promoted and smooth rotation of the spherical roller is ensured, which reduces induced thrust when transmitting rotational torque while the joint takes an operating angle. The vibration characteristics of the universal joint can be improved.

[Brief description of the drawings]

FIG. 1 is a partial sectional view (FIG. A) showing an embodiment of the present invention,
Partial cross-sectional view showing a spherical roller and a needle roller (FIG. B)
It is.

FIG. 2 is a partial cross-sectional view showing a spherical roller.

FIG. 3 is a partial cross-sectional view showing a spherical roller and a needle roller according to another embodiment of the present invention.

FIG. 4 is a partial cross-sectional view showing a spherical roller and a needle roller according to another embodiment of the present invention.

FIG. 5 is a vertical cross-sectional view showing a conventional configuration.

FIG. 6 is a vertical cross-sectional view showing a state when the tripod type constant velocity universal joint having the configuration shown in FIG. 5 has an operating angle.

FIG. 7 is a cross-sectional view showing a conventional configuration.

FIG. 8 is a diagram showing measurement results of induced thrust.

FIG. 9 is a cross-sectional view showing a conventional configuration.

FIG. 10 is a cross-sectional view showing a conventional configuration.

FIG. 11 is a cross-sectional view showing a conventional configuration.

[Explanation of symbols]

 2 Trunnion member 2a Leg shaft 2a1 Outer diameter surface 3 Needle roller 3a Rolling surface L'Axial length of rolling surface 41 Spherical roller 41a Cylindrical contact surface 41c Cut portion 41d Cut portion h Axial length of cylindrical contact surface It

Claims (4)

[Claims] 1. A diametrically projecting three leg shafts, a plurality of needle rollers rotatably arranged on the outer diameter surface of the leg shaft, and a needle roller on the outer diameter surface of the leg shaft. Tripod type constant velocity with a spherical roller that is rotatably fitted, has a cylindrical contact surface that contacts the rolling surface of the needle roller in its inner diameter, and has a leg shaft that allows displacement in the axial direction. In the trunnion member of the universal joint, the axial length of the cylindrical contact surface of the spherical roller is made smaller than the axial length of the rolling surface of the needle roller, and the spherical roller has a tip end side or a base end of the leg shaft. The trunnion member of a tripod type constant velocity universal joint, characterized in that the entire area of the cylindrical contact surface of the spherical roller contacts the rolling surface of the needle roller even when the maximum displacement is made in either direction. . 2. Three radially extending leg shafts, a plurality of needle rollers rotatably arranged on the outer diameter surface of the leg shaft, and needle rollers on the outer diameter surface of the leg shaft. Tripod-type constant velocity with a spherical roller that is rotatably fitted and has a cylindrical contact surface that contacts the rolling surface of the needle roller in its inner diameter, and that the displacement of the leg shaft in the axial direction is restricted. In the trunnion member of the universal joint, the trunnion of the tripod type constant velocity universal joint is characterized in that the axial length of the cylindrical contact surface of the spherical roller is made smaller than the axial length of the rolling surface of the needle roller. Element. 3. The trunnion member for a tripod type constant velocity universal joint according to claim 1, wherein both ends of the inner diameter of the spherical roller are cut by cut portions. 4. The axial length of the cylindrical contact surface of the spherical roller is 40 to 60% of the axial length of the rolling surface of the needle roller. Two
Alternatively, the trunnion member of the tripod type constant velocity universal joint according to item 3.