JP2000291676A - Tripod constant velocity universal joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the induction thrust in a tripod constant velocity universal joint and to reduce the vibration. SOLUTION: A spherical roller to be mounted on a leg shaft 22 is formed by an inner roller 42, an outer roller 46 and an intermediate roller 44 interposed between both rollers, and the inner roller 42 and the intermediate roller 44, and the intermediate roller 44 and the outer roller 46 are respectively face contacted with one another. Whereby the bearing pressure is lowered, in particular, the sliding resistance in the transmission of torque is reduced in a state that the joint takes an operating angle, whereby the induction thrust is reduced.

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 power transmission in automobiles and 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 is shown in FIG.
As shown in (A), the outer ring (1) is connected to one of the two shafts on the driving side and the driven side, and the tripod member (3) is connected to the other axis. The outer ring (1) is provided with an axial track groove (2) at three equally spaced positions on the inner circumference,
The tripod member (3) is provided with a leg shaft (4) projecting in the radial direction at a position equally divided in the circumferential direction. A spherical roller (5) is rotatably attached to a leg shaft (4) of the tripod member (3) via a needle roller (7), and the roller (5) is attached to the track groove (2) of the outer race (1). ) So that torque is transmitted between the outer ring (1) and the tripod member (3). Even when the drive shaft and the driven shaft are at an angle, they are kept at a constant speed. And maintain relative displacement and axial relative displacement (plunging)
Can be tolerated.

As shown in FIG. 7, a tripod member (3)
There is also known a tripod type constant velocity universal joint in which a spherical roller attached to a leg shaft (4) is formed by combining an inner roller (8) and an outer roller (9) (Japanese Patent Publication No. 3-152).
No. 9, JP-A-9-14280). The inner roller (8) has a spherical outer peripheral surface, and the outer roller (9) arranged on the outer periphery is in line contact with the spherical outer peripheral surface of the inner roller (8) on the cylindrical inner peripheral surface. ing. The outer peripheral surface of the outer roller (9) is spherical and is guided by a roller guide surface (6) formed on circumferentially opposed side walls of the track groove (2) of the outer ring (1). Since the spherical outer peripheral surface of the inner roller (8) is in line contact with the cylindrical inner peripheral surface of the outer roller (9), the inner roller (8) and the outer roller (9) rotate relative to each other. The relationship is such that relative movement in the axial direction and swinging motion are possible. Therefore, even when torque is transmitted with the joint at an operating angle, the attitude of the outer roller (9) is maintained parallel to the axis of the outer ring (1), and the outer roller (9) rolls smoothly. Can be.

[0004]

In the conventional structure shown in FIG. 6A, considering the case where torque is transmitted in a state where the outer race (1) and the tripod member (2) are at an operating angle, FIG.
As shown in (B), each spherical roller (5) and the roller guide surface (6) of the cylindrical track groove (2) have an oblique relationship with each other, so that the spherical roller (5) performs a correct rolling motion. Can not. That is, the spherical roller (5) tends to roll in the direction indicated by the arrow (A) in FIG. 6A, while the track groove (2) is cylindrical and is aligned with the axis of the outer ring (1). Since they are parallel, the spherical roller (5) moves while being restrained by the roller guide surface (6). As a result, the roller guide surface (6) and the spherical roller (5)
Slip occurs between each other to generate heat, and this slip induces an axial force (thrust), which causes vibration.

FIG. 6 shows the mechanism of induced thrust generation.
The following is a description of (C) to (E).
Here, FIG. 6 (C) illustrates the positional relationship between the outer ring (1) and the tripod member (3) when torque is transmitted in a state where the outer ring (1) takes an operating angle, and FIG. 6 (D). Is a more schematic representation of it. FIG. 6E is a graph in which the horizontal axis indicates the joint phase angle and the vertical axis indicates the induced thrust, and shows the induced thrust obtained by synthesizing the induced thrust on each leg shaft (4).

When the joint rotates from the state shown in FIG.
The spherical roller (5) attached to the leg shaft (4) of the tripod member (3) repeats reciprocating motion in the axial direction of the outer ring while being restricted by the roller guide surface (6) of the outer ring (1). At this time, the three spherical rollers (5) slide from point P to point P ', point Q to point Q', point R to point R ', respectively, as shown in FIG. Then, the direction is changed to the opposite direction, and one rotation of the joint makes one reciprocation on the roller guide surface (6). A thrust is induced in the axial direction between the spherical roller (5) and the roller guide surface (6) having such a motion by a contact force acting naturally as a power transmission joint.

When the joint rotates, each spherical roller (5)
The direction and magnitude of the thrust generated by the rotation vary depending on the rotation phase, and as shown in FIG. 6C, the two spherical rollers (5) move to the left of the outer ring (1), and the other spherical roller (5) moves to the left. The rollers (5) each pull to the right and induce a thrust of compression. Thus, three spherical rollers (5)
The total of the thrust generated by the rotation fluctuates forward and backward with three cycles during one rotation of the joint as shown in FIG.
The large amplitude of the fluctuations causes various vibration problems of the automobile.

In the conventional structure shown in FIG. 7, a single spherical roller (5) is formed by combining a spherical roller attached to a leg shaft (4) with an inner roller (8) and an outer roller (9). Compared with the used one, there is an advantage that the induced thrust when transmitting the torque in a state where the outer ring (1) and the tripod member (3) take an operating angle is reduced. An object of the present invention is to further reduce the induced thrust and provide a tripod-type constant velocity universal joint with less vibration.

[0009]

According to the present invention, there is provided an outer race having a track groove extending in an axial direction at an inner circumferential position at three equally-spaced positions, and a radially extending track at three equally-spaced positions at a circumferential position. A tripod member having a protruding leg shaft, and a roller rotatably mounted on each leg shaft and housed in a track groove of an outer ring, wherein the roller is constituted by an inner roller and an outer roller, and an outer periphery of the inner roller is provided. In a tripod type constant velocity universal joint in which a surface is formed in a spherical shape, an inner peripheral surface of an outer roller is formed in a cylindrical surface, and an outer roller is guided by a roller guide surface of an outer ring on an outer peripheral surface thereof. A tripod-type constant velocity universal joint characterized in that an intermediate roller having a concave spherical inner peripheral surface corresponding to the outer peripheral surface of the inner roller and a cylindrical outer peripheral surface is interposed between the two rollers.

In the conventional two-stage roller type joint (FIG. 7), since the inner and outer rollers are in line contact with each other, the surface pressure is high.
By forming a three-stage roller structure with an intermediate roller of the above shape interposed, the contact pressure between the inner roller and the intermediate roller, and the contact portion between the intermediate roller and the outer roller decreases, so that each roller has a smooth behavior. Is guaranteed. Therefore, the slip resistance is reduced, and the induced thrust can be further reduced.

According to a second aspect of the present invention, in the tripod type constant velocity universal joint according to the first aspect, the inner roller is a sphere having a center of curvature on the axis of the leg shaft.

According to a third aspect of the present invention, in the tripod type constant velocity universal joint according to the first aspect, the inner roller has a flattened spheroidal shape having a center of curvature at a position radially away from the axis of the leg shaft. There is a feature.

According to a fourth aspect of the present invention, in the tripod type constant velocity universal joint according to any one of the first to third aspects, the outer peripheral surface of the outer roller and the roller guide surface are in angular contact.

According to a fifth aspect of the present invention, in the tripod type constant velocity universal joint according to any one of the first to fourth aspects, the end surface of the outer roller on the tip end side of the leg shaft is not in contact with the outer ring.

According to a sixth aspect of the present invention, in the tripod type constant velocity universal joint according to any one of the first to fifth aspects, the inner roller is restrained from moving in the axial direction of the leg shaft.

According to a seventh aspect of the present invention, in the tripod constant velocity universal joint according to the sixth aspect, the movement of the inner roller in the axis direction of the leg axis is restricted by a washer mounted on the outer periphery of the leg axis.

According to an eighth aspect of the present invention, in the tripod type constant velocity universal joint according to any one of the first to seventh aspects, at least one of the outer peripheral surface of the intermediate roller and the inner peripheral surface of the outer roller is provided with an oil groove. Features.

According to a ninth aspect of the present invention, in the tripod type constant velocity universal joint according to any one of the first to seventh aspects, a lubricating film is provided on at least one of the outer peripheral surface of the intermediate roller and the inner peripheral surface of the outer roller. Features.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. As far as the basic configuration as a tripod type constant velocity universal joint is concerned, neither the present invention nor the conventional one shown in FIG. 7 is changed.

First, the embodiment shown in FIG. 1 will be described. A tripod type constant velocity universal joint comprises an outer ring (1) connected to one of two drive side and driven side shafts to be connected.
0) and a tripod member (20) coupled to the other shaft are main components.

The outer race (10) has a substantially cylindrical cup shape with one end opened and the other end closed, and is provided with a track groove (12) extending in the axial direction at three equally spaced positions on the inner circumference. Roller guide surfaces (14) are formed on circumferentially opposite side walls of each track groove (12).

The tripod member (20) has a serration hole or a spline hole (28) for coupling to the other of the two shafts to be connected, and is radially positioned at three equally circumferential positions. It has a protruding leg shaft (22). Each leg shaft (22) carries a roller assembly (40), which is mounted in the track groove (1) of the outer race (10).
2) housed inside.

The configuration around the roller assembly (40) will be described in detail. A plurality of needle rollers (32) are arranged on a cylindrical outer peripheral surface (24) of a leg shaft (22) of a tripod member (20). A roller assembly (40) including an inner roller (42), an intermediate roller (44), and an outer roller (46) is fitted around the outer periphery of the needle roller row. To prevent the needle rollers (32) and the inner roller (42) from slipping out and moving in the axial direction, washers (34, 36) are placed at both ends of the needle rollers (32) and the inner roller (42). A retaining ring (38) is mounted in an annular groove (26) formed at the tip of the shaft (22).

The inner peripheral surface of the inner roller (42) is cylindrical and forms the outer raceway surface of the needle roller (32). The cylindrical outer peripheral surface (24) of the leg shaft (22) becomes the inner raceway surface of the needle roller (32). That is, the needle rollers (32) are rotatably interposed between the cylindrical outer peripheral surface (24) of the leg shaft (22) and the cylindrical inner peripheral surface of the inner roller (42). The outer peripheral surface of the inner roller (42)
Here, the generatrix of the outer peripheral surface of the inner roller (42) is
FIG. 2B shows an example of a convex arc having a radius of curvature R ₁ having a center of curvature (O ₁ ) on the axis 2). In this case, the inner roller (42) is a sphere (strictly, a partial sphere obtained by cutting both ends in the leg axis direction), but in addition, it is located at a position radially away from the axis of the leg shaft (22). A flattened spheroidal shape having a center of curvature can also be used.

The intermediate roller (44) has a concave spherical inner peripheral surface having a shape corresponding to the spherical outer peripheral surface of the inner roller (42).
It is in spherical or linear contact with the inner roller (42).
As shown in FIG. 2 (B), by providing an undercut (43) on the intermediate roller (42), interference between the washer (34) and the boss of the tripod member (20) at an angle is avoided. In addition, the incorporation of the inner roller (42) and the intermediate roller (44) in spherical contact can be made possible.
The undercut (43) is formed on the entire inner peripheral surface of the intermediate roller (44), and the minimum inner diameter of the undercut portion is slightly smaller than the maximum diameter of the inner roller (42). In addition,
In FIG. 2B, the outer peripheral surface of the inner roller (42) and the inner peripheral surface of the intermediate roller (44) are displayed as having the same radius of curvature (R ₁ ). Tolerances are set for the purpose of allowing sliding. The outer peripheral surface of the intermediate roller (44) is cylindrical.

The inner peripheral surface of the outer roller (46) is cylindrical, and is fitted to the cylindrical outer peripheral surface of the intermediate roller (44). The intermediate roller (44) and the outer roller (46) are relatively rotatable,
In addition, axial displacement is possible. The outer roller (46) is in contact with the roller guide surface (14) of the outer ring (10) on its outer peripheral surface. The outer peripheral surface of the outer roller (46) is a spherical convex curved surface, and here, a radius R having a center of curvature (O ₂ ) at a position radially away from the axis of the leg shaft (22). ₂ illustrates a case of a convex arc (see FIG. 2B).

When the outer roller (46) moves in the axial direction of the outer ring (10), it is guided by the roller guide surface (14) of the outer ring (10) on its outer peripheral surface. The cross-sectional shape of the roller guide surface (14) is a concave arc corresponding to the outer peripheral surface of the outer roller (46).
Contact can also be made. Roller guide surface to realize such an angular contact structure (14)
For example, a Gothic arch shape or a V-shaped shape as shown in FIG. If the generatrix of the outer peripheral surface of the outer roller (46) is an arc having a center of curvature (O ₂ ) at a position radially away from the axis of the leg shaft (22) as shown in the figure, the roller guide surface (14) Even if the cross-sectional shape is a concave arc corresponding to the outer peripheral surface of the outer roller (46), the outer roller (46) moves in the axial direction of the outer ring (10) while maintaining its posture. Further, when the angular contact structure is adopted, the posture of the outer roller is further stabilized. Therefore, the outer rollers (4
It is possible to omit the flange provided along the upper edge and / or lower edge of the roller guide surface (14) in order to stabilize the posture by restricting the inclination and runout of 6), and FIG. Such a configuration is shown.

Next, in the embodiment shown in FIG. 3, in order to enable the assembling of the inner roller (42) and the intermediate roller (44) which come into contact with the spherical surface, in addition to the above-mentioned undercut (43), a groove is provided. (45) is provided. As shown in FIG. 3 (A), a pair of grooves (45) are formed at diametrically opposed positions on the inner peripheral surface of the intermediate roller (44), and the inner roller (42) with its axis perpendicular to the axis. Is an acceptable width dimension. Then, as shown in FIG. 3B, the groove (45) extends from one end surface of the intermediate roller (44) to the maximum inner diameter of the spherical inner peripheral surface. FIGS. 3A and 3B show the intermediate ring (4
FIG. 3C shows a state in which the inner ring (42) is inserted into the insertion groove (45). When the inner ring (42) is rotated from this state as shown in FIG. And the intermediate ring (44) are assembled together in a state of spherical contact.

In the tripod-type constant velocity universal joint having the above-described structure, when the joint transmits the torque at an operating angle, the angular displacement between the leg shaft (22) and the roller guide surface (14) is spherical. The angular displacement between the contacting inner roller (42) and the intermediate roller (44) is tolerated, and the relative position change is caused by the axial displacement between the intermediate roller (44) and the outer roller (46). Allowed by. Since the inner roller (42) and the intermediate roller (44) and the intermediate roller (44) and the outer roller (46) are in surface contact with each other, the inner roller and the outer roller are in line contact with each other. The surface pressure is lower than that of In addition, the grease easily intervenes between the contact surfaces as compared with the case of the line contact, and the oil film is easily retained, so that the sliding resistance is reduced.
As a result, when torque is transmitted with the joint at an operating angle, the slide resistance of the roller assembly (40) moving in the axial direction of the outer ring (10) is reduced, and as a result, due to the slide resistance. Induced thrust is also reduced.

An oil groove may be provided on the outer peripheral surface of the intermediate roller (44), the inner peripheral surface of the outer roller (46), or both.
Specific examples of the oil groove include a circumferential groove, a spiral groove, and a dimple. The oil groove serves to draw grease between the contact surfaces of the two rollers and to hold the grease and to replenish the grease as needed, thereby maintaining a good lubricating state and contributing to a reduction in slip resistance. For the same purpose, a lubricating coating may be provided on the outer peripheral surface of the intermediate roller (44) or the inner peripheral surface (46) of the outer roller or both. The coating may take various forms, such as application of a lubricant, coating or other surface treatment.

In the illustrated embodiment, the width dimension of the outer roller (46) is asymmetric with respect to the center of the spherical surface.
That is, as shown in FIG. 2B, the width (L ₂ ) on the outer diameter side is longer than the width (L ₁ ) on the inner diameter side of the joint with respect to the center of the spherical surface (H). When the outer ring (10) has no flange as described above, the outer ring (10) and the end surface of the outer roller (46) are in contact even if the leg end of the outer roller (46) is expanded in the width direction. I will not do it. When the outer roller (46) slides in the axial direction of the outer ring (10) along the track guide surface (14) by extending the tip end side of the outer roller (46) in the width direction, the outer roller (46) 46) is the inner roller (42)
Outer roller (46) when trying to swing and displace following
, The induced thrust is more effectively reduced.

[0032]

In order to verify the effect of the present invention, the induced thrust tertiary component under different working angles was measured for the conventional joint of FIG. 7 and the joint of the present invention. The test conditions were as follows: torque T = 294 Nm, rotational speed N = 150 rpm, operating angles = 6 °, 8 °, 10 °, 12.5 °.

FIG. 4 is a plot of measured values of the primary and tertiary components of the induced thrust for a conventional joint. Similarly, FIG. 5 plots measured values of the primary and tertiary components of the induced thrust for the joint of the present invention. As is clear from a comparison between FIG. 4 and FIG. 5, the conventional joint shows a value similar to the tertiary component in the primary component,
The joint according to the invention has a very low primary component and a wide angle of 12.
Below 5 deg), the tertiary component also decreases. This supports the effect of the present invention of reducing induced thrust. In the conventional joint shown in FIG. 7, since the contact between the inner and outer rollers is a line contact, the surface pressure is high, and this is particularly noticeable at a wide angle. According to the present invention, the intermediate roller is interposed. As a result, it is considered that the surface pressure of each part was reduced, thereby further reducing the induced thrust.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of a tripod type constant velocity universal joint showing an embodiment of the present invention.

FIG. 2A is a cross-sectional view of a roller guide surface of an outer ring, and FIG.
FIG. 3 is an exploded sectional view of the roller assembly.

FIG. 3 is an explanatory view showing an assembling procedure of an inner ring and an intermediate ring according to another embodiment of the present invention,
(A) is a cross-sectional view taken along line BB of the intermediate ring in a state where the inner roller is inserted into the groove of the intermediate roller, (B) is a bottom view of (A), and (C) is a C- post-assembly. It is C sectional drawing.

FIG. 4 is a graph plotting a primary component and a tertiary component of an induced thrust with respect to an operating angle in a conventional joint.

FIG. 5 is a graph plotting a primary component and a tertiary component of an induced thrust with respect to an operating angle in the joint of the present invention.

FIG. 6 shows a conventional tripod type constant velocity universal joint,
(A) is a vertical cross-sectional view in an operating angle, (B) is a schematic perspective view of a roller and a roller guide surface, (C) is a schematic perspective view, (D) is a schematic diagram, and (E). Is a graph showing the relationship between the joint phase and the induced thrust.

FIG. 7 shows another conventional tripod type constant velocity universal joint,
(A) is a longitudinal sectional view, and (B) is a transverse sectional view.

[Explanation of symbols]

 10 Outer ring 12 Track groove 14 Roller guide surface 20 Tripod member 22 Leg axis 24 Outer peripheral surface 26 Annular groove 28 Serration (spline) hole 32 Needle roller 34 Washer 36 Washer 38 Retaining ring 40 Roller assembly 42 Inner roller 43 Undercut 44 Intermediate roller 45 Insert groove 46 Outer roller

Claims (9)

[Claims] 1. An outer race having a track groove extending in an axial direction at an inner circumferential circumferentially tri-segmented position, a tripod member having a radially projecting leg shaft at a circumferentially trisected position,
A roller rotatably mounted on each leg shaft and housed in a track groove of an outer ring, the roller comprising an inner roller and an outer roller, an outer peripheral surface of the inner roller being formed in a spherical shape, an outer roller The inner peripheral surface of is formed into a cylindrical surface, and
In a tripod type constant velocity universal joint in which an outer roller is guided by a roller guide surface of an outer ring on an outer peripheral surface thereof, a concave spherical inner peripheral surface corresponding to an outer peripheral surface of the inner roller is provided between the two rollers. A tripod type constant velocity universal joint comprising an intermediate roller having a cylindrical outer peripheral surface interposed therebetween. 2. The tripod constant velocity universal joint according to claim 1, wherein the inner roller is a sphere having a center of curvature on the axis of the leg shaft. 3. The tripod-type constant-velocity universally movable body according to claim 1, wherein the inner roller has a flattened spheroidal shape having a center of curvature at a position radially away from the axis of the leg shaft. Fittings. 4. The tripod constant velocity universal joint according to claim 1, wherein the outer peripheral surface of the outer roller and the roller guide surface make angular contact. 5. The tripod-type constant velocity universal joint according to claim 1, wherein an end surface of the outer roller on the tip end side of the leg shaft is not in contact with the outer ring. 6. The tripod constant velocity universal joint according to claim 1, wherein the inner roller is restrained from moving in the axial direction of the leg shaft. 7. The tripod constant velocity universal joint according to claim 6, wherein the movement of the inner roller in the axial direction of the leg shaft is restricted by a washer mounted on the outer periphery of the leg shaft. 8. The tripod type constant velocity universal joint according to claim 1, wherein an oil groove is provided on at least one of an outer peripheral surface of the intermediate roller and an inner peripheral surface of the outer roller. 9. The tripod-type constant velocity universal joint according to claim 1, wherein a lubricating coating is provided on at least one of an outer peripheral surface of the intermediate roller and an inner peripheral surface of the outer roller.