Constant velocity joint

Abstract

To increase a crossing angle.SOLUTION: A plurality of rolling grooves 11,7 are formed in each of an outer ring 5 and an inner ring 6, and a plurality of balls 1 arranged in the rolling grooves 11,7 to transmit torque are held by a cage 12. The outer ring 5 is composed of a cylindrical outer case 8 and an inner case 9 which is movable in the axial direction of the outer case 8 inside the outer case 8, is restrained in the circumferential direction, and forms an annular shape as a whole. The inner case 9 includes a plurality of sliding pieces 10 divided in the circumferential direction corresponding to the balls 1 and having rolling grooves 11 formed on the inner surface, and further includes a pressing plate 13 disposed inside the outer case 8 and pressed against end portions of the plurality of sliding pieces 10 by an elastic member 14, and a receiving plate 15 provided on the second rotating member 4 in a state of protruding outward in the radial direction and abutting against the plurality of sliding pieces 10.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a constant velocity joint, and more particularly to a sliding type constant velocity joint. [Background technology]

[0002] This type of constant velocity joint is a shaft coupling configured to maintain a constant rotational speed of the inner and outer rings during one rotation by interposing balls between the inner and outer rings and moving in the direction of rolling grooves formed on the outer periphery of the inner ring and the inner periphery of the outer ring. An example is described in Patent Document 1.

[0003] In the constant velocity joint shaft coupling structure described in Patent Document 1, a constant velocity joint is provided on each of the rotating members provided at both axial ends, and the shaft between the constant velocity joints is configured to be extendable and retractable. The so-called intermediate shaft has a cylindrical outer member and an inner member housed therein, and is configured as a constant velocity joint with the outer member as the outer ring and the inner member as the inner ring. That is, a plurality of axially oriented rolling grooves are formed on the inner surface of the outer member, and a corresponding plurality of axially oriented rolling grooves are formed on the outer surface of the inner member. Balls held by a cage are movably housed in these rolling grooves. Therefore, the balls held by the cage and the inner member can move axially inside the outer member, making the intermediate shaft as a whole extendable and retractable. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-156300 Summary of the Invention [Problem to be solved by the invention]

[0005] The advantage of a constant velocity joint is that it can maintain a constant rotational speed during one rotation even when the axes of a pair of rotating shafts to transmit torque intersect at a predetermined angle. In other words, when the central axes of the outer and inner rings intersect at a predetermined angle, the balls move within the rolling grooves of the outer and inner rings, and torque is transmitted via the balls and rolling grooves at a position half the intersecting angle of the rotating shafts, ensuring what is known as constant velocity.

[0006] In a sliding constant velocity joint or an intermediate shaft joint described in Patent Document 1, the outer ring or an outer member equivalent thereto (hereinafter, simply referred to as the outer ring) is cylindrical. The inner ring or an inner member equivalent thereto (hereinafter, simply referred to as the inner ring) housed therein is tilted relative to the outer ring, causing the rotating axes connected to the outer ring and the inner ring to intersect at a predetermined angle. One of the rotating shafts connected to the inner ring is inserted inside the outer ring. Therefore, when the rotating shaft and the inner ring are tilted relative to the outer ring, the middle portion of the rotating shaft comes into contact with the open end of the cylindrical outer ring. The rotating shafts are allowed to intersect within a range that does not cause such contact. However, if the rotating shaft connected to the inner ring is inserted deeply into the outer ring, the intersecting angle at which the shaft does not come into contact with the open end of the outer ring becomes smaller. In other words, in the past, such limitations on the intersecting angle have limited the applications of constant velocity joints, leaving room for improvement in this area.

[0007] Furthermore, when the rotating shafts that transmit torque intersect at the constant velocity joint, the inner ring tilts inside the outer ring. As a result, the balls held in a circumferential arrangement on the outer periphery of the inner ring move toward the open end of the outer ring in one circumferential direction and toward the inner edge of the outer ring in the other circumferential direction. The amount of movement increases as the intersecting angle of the rotating shafts increases. Therefore, if the amount of movement toward the open end of the outer ring increases due to the large intersecting angle, the balls may fall out of the rolling grooves of the outer ring. Therefore, the intersecting angle of the rotating shafts must be limited to a range that prevents the balls from falling out of the rolling grooves of the outer ring. This limitation can be alleviated by increasing the axial length of the outer ring, but as mentioned above, this increases the likelihood that the rotating shafts will come into contact with the open end of the outer ring, resulting in a limitation on the intersecting angle.

[0008] The present invention has been made in view of the above-mentioned technical problems, and has as its object to provide a constant velocity joint that allows the intersection angle to be increased. [Means for solving the problem]

[0009] In order to achieve the above object, the present invention provides a constant velocity joint having an outer ring connected to a predetermined first rotating member, and an inner ring inserted inside the outer ring and connected to a predetermined second rotating member, a plurality of rolling grooves formed on the inner circumferential surface of the outer ring and the outer circumferential surface of the inner ring, a plurality of balls arranged in the rolling grooves and connecting the outer ring and the inner ring so as to be able to transmit torque, and held by a cage so as to maintain a constant distance from each other, wherein the outer ring is composed of a cylindrical outer case and an inner case that is annular as a whole and is movable inside the outer case in the axial direction of the outer case but is constrained in the circumferential direction, the inner case has a plurality of sliding pieces that are divided circumferentially corresponding to the balls and have the rolling grooves formed on their inner surfaces, and the joint further comprises a pressing plate that is arranged inside the outer case and pressed against ends of the sliding pieces by elastic members, and a receiving plate that is provided on the second rotating member in a state where it protrudes outward in the radial direction and against which the sliding pieces abut. [Effects of the Invention]

[0010] According to the constant velocity joint of the present invention, the support plate provided on the second rotating member is inclined relative to the outer ring at the open end of the outer ring in accordance with the intersection angle between the first rotating member and the second rotating member. The inner case, which is pressed against the support plate by the elastic force of the elastic member, is composed of sliding pieces that are separated from each other in the circumferential direction. Therefore, when the support plate is inclined, the sliding pieces extend from the outer case at a portion separated from the open end of the outer case, while at the opposite portion in the circumferential direction, the support plate approaches the open end of the outer case, causing the sliding pieces to recede toward the outer case. The amount of extension and retraction of the sliding pieces increases depending on the intersection angle of the rotating members (the inclination angle of the inner ring relative to the outer ring). Therefore, even if the intersection angle is large, balls are prevented from falling off the outer ring (sliding pieces), and at the same time, contact (or interference) between the second rotating member and the outer ring (sliding pieces) is prevented. Ultimately, fewer restrictions on the intersection angle make it possible to obtain a constant velocity joint with a large intersection angle. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic longitudinal sectional view for explaining an embodiment of the present invention. [Figure 2] 2 is a cross-sectional view of the constant velocity joint as viewed from the axial direction. FIG. [Figure 3] FIG. 2 is a vertical cross-sectional view similar to FIG. 1, but with an intersecting angle. DETAILED DESCRIPTION OF THE INVENTION

[0012] Next, an embodiment of the present invention will be described with reference to the accompanying drawings. Note that the embodiment described below is merely an example of how the present invention can be implemented, and is not intended to limit the present invention.

[0013] An embodiment of the present invention is a sliding-type constant velocity joint that transmits torque via balls, an example of which is shown schematically in Figures 1 and 2. Figure 1 is a cross-sectional view taken along a plane passing through the centers of balls 1 positioned opposite each other in the radial direction, and Figure 2 is a cross-sectional view viewed from the axial direction. This constant velocity joint 2 connects a first rotating member 3 and a second rotating member 4, such as rotating shafts, which transmit torque to each other.

[0014] The outer ring 5 connected to the first rotating member 3 has an overall cylindrical shape with one end open in the axial direction, and the inner ring 6 connected to the second rotating member 4 is disposed inside the outer ring 5. The inner ring 6 has a configuration similar to that of inner rings in conventional constant velocity joints, and its outer shape is a nearly spherical shape with both axial ends cut away. On its outer circumferential surface, rolling grooves 7 are formed, extending from one end to the other, in the same number as the balls 1 and spaced equally apart in the circumferential direction. The number of balls 1 is generally six or eight. The second rotating member 4 passes through the inner ring 6 along its central axis, connecting the second rotating member 4 and the inner ring 6 together as a single unit.

[0015] The outer ring 5 includes an outer case 8 to which the first rotating member 3 is connected, and an inner case 9 inserted inside the outer case 8 so as to be slidable in the axial direction. The outer case 8 is a cylindrical member with one end in the axial direction open. In contrast, the inner case 9 is composed of a plurality of sliding pieces 10 that form a cylindrical (or annular) shape as a whole. The sliding pieces 10 are members that are long in the axial direction and have rolling grooves 11 formed on their inner surfaces to allow the balls 1 to roll, and therefore the number of sliding pieces 10 provided is the same as the number of balls 1.

[0016] The sliding pieces 10 are arranged side by side in the circumferential direction of the outer case 8, and adjacent sliding pieces 10 are in contact with each other, forming a cylindrical shape as a whole. Each sliding piece 10 is movable in the axial direction relative to the outer case 8, and is constrained (or integrated) with the outer case 8 in the circumferential direction (rotational direction). Therefore, the inner peripheral surface of the outer case 8 may be formed with a groove-like portion along the axial direction into which each sliding piece 10 is fitted. In addition, the shape of the inner surface of the sliding piece 10 or the shape of the rolling groove 11 formed therein is an arc-like shape that is convex outward in the radial direction when viewed from the inner peripheral side in the cross-sectional view shown in FIG. 1. This is to maintain contact with the ball 1 or a state in which the ball 1 is accommodated when an intersection angle is formed.

[0017] The rolling grooves 7 in the inner ring 6 and the rolling grooves 11 in the sliding piece 10 described above face each other in the radial direction of the outer ring 5 or the inner ring 6. The balls 1 are fitted into these rolling grooves 7, 11 and are held by these rolling grooves 7, 11 so as to be able to transmit torque. The balls 1 can move within the rolling grooves 7, 11 in their axial direction (the left-right direction in Figure 1 ) but cannot move in the circumferential direction perpendicular to this, so torque is transmitted between the inner ring 6 and the outer ring 5 via the balls 1. The balls 1 are held rotatably and at a constant interval by a cage 12, which is an annular member having through holes corresponding to the balls 1.

[0018] A pressure plate 13 is disposed inside the outer case 8 on the end side of each sliding piece 10 (the end side on the right side in FIG. 1 ). The pressure plate 13 is a disk-shaped member with an outer diameter approximately equal to the inner diameter of the outer case 8, and is pressed against the end of each sliding piece 10. A spring 14 is provided on the opposite side of the pressure plate 13 from the sliding piece 10, as an elastic member that presses the pressure plate 13 toward the sliding piece 10 (the open end side of the outer case 8). As will be described later, the pressure plate 13 tilts according to the intersection angle of the rotating members 3 and 4. Therefore, a plurality of springs 14 may be provided at equal intervals in the circumferential direction to allow the pressure plate 13 to tilt. Alternatively, the springs 14 may be provided so as to press the center of the pressure plate 13. In order to reliably maintain contact between the end of the sliding piece 10 and the pressing plate 13 even when the pressing plate 13 is tilted, it is preferable to provide a flange-like portion extending radially inward at the end of the sliding piece 10.

[0019] A support plate 15 is provided to regulate the position of the tip side (left side in FIG. 1) of the sliding piece 10 pressed by the spring 14. The support plate 15 is a disk-shaped member attached to the second rotating member 4, and is a flange-shaped portion that protrudes radially outward from the second rotating member 4. Therefore, when an intersection angle is formed between the first rotating member 3 and the second rotating member 4, the support plate 15 is displaced radially from a position on the central axis of the first rotating member 3 or the outer ring 5, and is also tilted relative to the central axis of the first rotating member 3 or the outer ring 5. The radius of the support plate 15 is set to a size that allows a predetermined sliding piece 10 to abut against it even in this tilted state.

[0020] The intersection angle in a constant velocity joint is the angle of deviation between the central axis of one of two rotating members that transmit torque and the central axis of the other rotating member. Figure 3 shows the constant velocity joint 2 described above at a predetermined intersection angle θ. In Figure 3, the second rotating member 4 is tilted downward and leftward relative to the first rotating member 3. When tilted in this manner, the center of rotation is the center of the inner ring 6. Therefore, the flange-shaped support plate 15 attached to the second rotating member 4 also rotates around the center of the inner ring 6, displacing downward in Figure 3 at the open end of the outer ring 5 and tilting relative to the central axis O of the outer ring 5. As a result, the portion of the support plate 15 located below the central axis O of the outer ring 5 in Figure 3 moves toward the open end of the outer ring 5. Conversely, the portion located above the central axis O of the outer ring 5 in Figure 3 moves away from the open end of the outer ring 5.

[0021] The above-mentioned sliding piece 10 constituting a part of the outer ring 5 is pushed by the spring 14 and can move in the axial direction of the outer case 8, so the sliding piece 10 located above the central axis O of the outer ring 5 in FIG. 3 is pushed by the spring 14 and moves in the direction extending from the outer case 8. Therefore, even if the ball 1 located above the central axis O of the outer ring 5 in FIG. 3 moves toward the open end of the outer case 8, it is prevented from falling out of the rolling groove 11 on the outer ring 5 side (the rolling groove 11 of the sliding piece 10).

[0022] Conversely, the sliding piece 10 located above the central axis O of the outer ring 5 in Figure 3 is pushed by the support plate 15 and moves back toward the open end of the outer case 8 while compressing the spring 14. In other words, because the actual opening edge of the outer ring 5 moves back, the second rotating member 4 does not interfere with the sliding piece 10 (or the inner case 9 or the outer ring 5) even if the intersection angle θ is increased. In other words, because the restriction on increasing the intersection angle θ is relaxed, the constant velocity joint 2 described above can be a constant velocity joint with a large permissible intersection angle.

[0023] For example, when the first rotating member 3 is rotated, the outer ring 5 that is integral with it and the balls 1 that are engaged with the rolling grooves 11 thereof rotate. The balls 1 are engaged with the rolling grooves 7 of the inner ring 6, so torque is ultimately transmitted from the outer ring 5 via the balls 1 to the inner ring 6 and the second rotating member 4 that is integral with it. [Explanation of symbols]

[0024] 1 ball 2 Constant velocity joints 3,4 Rotating members 5 outer ring 6. Inner Circle 7,11 Rolling groove 8 outer case 9 Inner case 10 sliding piece 12 cages 13 Pressing plate 14 Spring 15 Support plate θ Intersection angle O center axis

Claims

[Claim 1] A constant velocity joint having an outer ring connected to a predetermined first rotating member and an inner ring inserted inside the outer ring and connected to a predetermined second rotating member, wherein a plurality of rolling grooves are formed on the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring, and a plurality of balls arranged in the rolling grooves and connecting the outer ring and the inner ring so as to be able to transmit torque are held by a cage so as to maintain a constant distance from each other, the outer ring is composed of a cylindrical outer case and an inner case that is annular as a whole and movable in the axial direction of the outer case but constrained in the circumferential direction within the outer case, the inner case includes a plurality of sliding pieces that are divided in the circumferential direction corresponding to the balls and have the rolling grooves formed on their inner surfaces, a pressing plate disposed inside the outer case and pressed against the ends of the plurality of sliding pieces by elastic members; The second rotary member further includes a receiving plate that is provided on the second rotary member and protrudes outward in the radial direction, against which the sliding pieces abut. A constant velocity joint characterized by:

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