JPH0689785B2 - Constant velocity universal joint - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a constant velocity universal joint used for a propulsion shaft and a drive shaft of an automobile, and in particular, is capable of maintaining a constant velocity while maintaining an operating angle and allowing relative displacement in the axial direction. The present invention relates to a universal joint.

[Prior art and its problems]

It has been proposed to use a slide type constant velocity universal joint, which is not restricted by an allowable angle, for a propulsion shaft of an automobile.
(For example, see Japanese Patent Laid-Open No. 56-75218) However, in the normal slide type constant velocity universal joint, there is a gap between the ball groove and the ball for smooth bending operability and reduction of axial sliding resistance. There is. As a result, vibrations caused by backlash in the circumferential and radial directions of the propulsion shaft,
Further, there remains a problem that it is difficult to balance the rotational balance of the propulsion shaft, and a propulsion shaft for an automobile, which has excellent vibration characteristics, has a simple structure, and is inexpensive, has been desired. In addition, the constant-velocity universal joint that allows angular displacement and axial displacement is used for the drive shaft of front-wheel drive vehicles and rear-wheel drive vehicles of the independent suspension system, such as when the drive shaft is idling when running or when stopped. In an operating condition in which angular displacement or axial displacement occurs while transmitting torque, the sliding resistance inside the joint during displacement is large, so the vibration from the engine side is transmitted to the vehicle body and causes occupant discomfort. Is left. That is, as shown in FIG. 5, the conventional slid type constant velocity universal joint has an outer ring (1) having a cylindrical surface (3) provided with a linear guide groove (2) and a guide for this outer ring (1). An inner ring (6) provided with a groove (4) that cooperates with the groove (2) to form a ball track, and has a partially spherical outer surface (5), and each groove (2), (4). ) And a ball pocket (8) for accommodating the torque transmitting ball (7), and a cylindrical inner surface (3) and an inner ring (6) of the outer ring (1). And a partial spherical inner and outer surfaces (9) and (10) each having a center of curvature arranged on both sides of the ball center line on the joint axis by being equally guided. Composed of a cage (11), an outer surface (5) of the inner ring (6) and a cage (11)
The inner surfaces (9) of the above are formed to have the same radius to make spherical contact, and the balls (7) are accommodated in the ball pockets (8) of the cage (11) with an appropriate interference.
Therefore, when vibration acts on the constant velocity universal joint, the outer ring (1)
And the ball (7), the inner ring (6) and the ball (7), and the outer ring (1) and the cage (11), but the ball (7) rotates. However, the sliding resistance is large, and particularly when the rotating torque is acting on the constant velocity universal joint, this sliding resistance is increased by the outer ring (1).
There is a problem that it is governed by the slip resistance at the contact part between the ball (7) and the ball (7) and at the contact part between the inner ring (6) and the ball (7). In order to solve the above problems, a spherical bush is slidably fitted around the shaft, and a cage is fitted between the spherical bush and the inner surface of the outer ring to reduce sliding resistance. A universal joint is known (US Pat. No. 3452558 and its corresponding Japanese Patent Publication No. 47).
-50054). However, in this case, the ball groove of the inner member fitted to the shaft,
Since the spherical bushes are arranged side by side in the axial direction, there is a drawback that the range of the sliding stroke of the spherical bushes cannot be set sufficiently large.

[Means for solving problems]

The configuration of the constant velocity universal joint according to the present invention includes: an outer cylinder provided with ball guide grooves on both inner side walls of three linear grooves and having land portions forming a part of a cylindrical inner surface between the linear grooves. The torque transmitting balls arranged in the ball guide grooves, and the torque transmitting balls at two corners in the circumferential direction of the leg outer peripheral surface provided in the radial direction facing the lands, respectively. A cage having a pocket for accommodating each of the cages and guided by the land portion on the inner surface of the outer cylinder and the outer surface of the spherical bush slidably fitted on the shaft; between the leg portions of the cage; Extend to the space between the straight groove,
It has three leg shafts each formed with two axially extending grooves for guiding the torque transmitting balls in cooperation with the ball guide grooves on both inner side walls of the linear groove, and is continuously provided to the leg shafts. And an inner member consisting of an annular base portion having an inner diameter surface engraved with serrations for torque transmission, and forming an outer surface of the cage in a partially spherical shape, the inner surface of which is the outer surface of the spherical bush. It is formed in a concave spherical surface along the surface, and these curvature centers are offset equidistantly to the axial center opposite sides with respect to the joint center.

【Example】

An embodiment of the present invention will be described with reference to FIGS. 3 straight grooves (22) on the inner surface of the outer cylinder (20)
A ball guide groove (24), in which the torque transmitting ball (23) rolls, is formed on both sides of each straight groove (22). The ball (23) is rotatably held by the inner member (25) and the cage (26). A land portion (21) forming a part of the cylindrical inner surface is formed between the linear grooves (22). The inner member (25) has leg shafts (27) arranged at equal angular intervals in correspondence with the three linear grooves (22) of the outer cylinder (20), and has a substantially cylindrical shape as a whole. A serration (30) that engages with the drive shaft (29) is engraved on the inner diameter of the annular base (28) corresponding to the root thereof. The axial movement of the inner member (25) is prevented by a clip () between the annular groove (31) formed on the serration (30) and the annular groove (32) formed on the drive shaft (29) side. 33). The cage (26) has a partially spherical outer peripheral surface (34) guided by the inner surface (21) of the outer cylinder (20), and the drive shaft (2).
9) has an inner peripheral surface (37) with a concave spherical surface (36) that fits into a spherical bush (35) slidably inserted into the drive shaft (29). Has become. The centers of curvature of the partially spherical outer peripheral surface (34) and the concave spherical surface (36) are equidistant from the joint center (O) (A),
In (B), the radii are formed in (R1) and (R2). Therefore, since (A) and (B) are equidistant from the joint center (O), the balls (23) are always on the bisector, that is, when the bending angle is (θ), each ball (23) Exists on a surface inclined by half the angle (θ / 2), and power is transmitted at a constant velocity as in the conventional one. The cage (26) has a trilobal shape, and three leg portions (38) are provided in the radial direction so as to be opposed to the land portion (21). This leg (38)
There are balls (23) on the two corners of the outer peripheral surface in the circumferential direction.
A retaining pocket (39) is formed, and the ball (23) is supported by the leg (38) and the leg shaft (27) of the inner member (25) extending into the space between the straight grooves (22). Holds in a pinch shape so that it can rotate freely. In the constant velocity universal joint of the present invention, when the outer cylinder (20) is axially displaced from the inner member (25), the balls (23) roll in the ball guide grooves (24) and the cage (26). Is the ball (23)
Moves in the axial direction by 1/2 of rolling. Therefore, the spherical bush (35) moves together with the cage (26). The spherical bush (35) slides between the clip (40) attached to the tip of the drive shaft (29) and the shaft serration (41). In order to reduce rolling resistance when the ball (23) rolls, it is good to provide a slight gap between the pocket (39) of the cage (26) and the ball (23), and the ball (23) is stable. In order to roll well, arc grooves (42) having a radius slightly larger than the radius of curvature of the ball are axially formed on both sides of the leg shaft (27) of the inner member (25). The contact angle (θ) of the ball (23) is shown in FIG. In this contact angle θ, the leg shaft (27) of the inner member (25) is driven by the drive shaft (29).
Since it exists at a position radially outward from, it becomes larger than when it exists at a position near the drive shaft (29).

【effect】

Since the present invention is configured as described above, it has the following effects. (I). Since the cage accommodating the balls can move relative to the inner member in the axial direction, the balls can reliably roll in the ball guide groove of the outer cylinder, and the sliding resistance of the joint is very small. (B). Since the stem of the inner member extends into the space between the legs of the cage and the straight groove, the spherical bush can be arranged inside the stem. Therefore, the sliding range of the spherical bush and the cage fitted thereto can be made long in the axial direction. (C). Since the contact angle of the ball can be increased, the load capacity increases.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention, and FIG.
The horizontal cross-sectional views, FIGS. 3 and 4 are perspective views of a cage and an inner member used in the present invention, and FIG. 5 is a vertical cross-sectional view of a conventional slide type constant velocity universal joint. 20 …… Outer cylinder 23 …… Torque transmission ball 24 …… Ball guide groove 25 …… Inner member 26 …… Cage 27 …… Leg shaft 29 …… Drive shaft 33, 40 …… Clip 34 …… Partial spherical shape Outer surface 35 …… Spherical bush 36 …… Concave spherical surface 38 …… Legs 39 …… Pocket

Claims (1)

[Claims] 1. An outer cylinder provided with ball guide grooves on both inner side walls of three linear grooves, and having land portions forming a part of a cylindrical inner surface between the linear grooves, and the ball guide grooves. And a pocket for accommodating the torque transmission ball, respectively, at two corner portions in the circumferential direction of the leg outer peripheral surface provided in the radial direction facing the respective land portions. A cage guided by the land portion on the inner surface of the outer cylinder and the outer surface of the spherical bush slidably fitted on the shaft, and between the legs of the cage and the straight groove. Extend to the void,
It has three leg shafts each formed with two axially extending grooves for guiding the torque transmitting balls in cooperation with the ball guide grooves on both inner side walls of the linear groove, and is continuously provided to the leg shafts. And an inner member consisting of an annular base portion having an inner diameter surface engraved with serrations for torque transmission, and forming an outer surface of the cage in a partially spherical shape, the inner surface of which is the outer surface of the spherical bush. A constant velocity universal joint characterized in that it is formed in a concave spherical surface along the surface, and these curvature centers are offset equidistantly to the joint center on opposite sides in the axial direction.