Constant velocity universal joint and ball cage thereof

Abstract

The constant velocity universal joint ball cage comprises an annular retainer body, the retainer body is provided with an outer surface and an inner surface, a plurality of windows are arranged in the circumferential direction of the retainer body at equal intervals, and the windows communicate with the outer surface and the inner surface; in the circumferential direction of the ball cage, the circumferential extension length L1 of the window on the outer surface is smaller than the circumferential extension length L2 of the window on the inner surface. The invention further provides a constant velocity universal joint which comprises an outer star wheel with a plurality of inner fairways on the inner wall, an inner star wheel with a plurality of outer fairways on the outer wall, the ball cage and a plurality of balls, the inner star wheel is arranged inside the outer star wheel, the ball cage is arranged between the inner star wheel and the outer star wheel, and the balls are located in the windows. And the outer ball groove is in contact fit with the inner ball groove. According to the constant velocity universal joint, the structure of the ball cage window is improved, so that the impact force between the ball body and the side wall of the window is reduced, the relative friction between parts in the constant velocity universal joint is reduced, and the transmission efficiency of the constant velocity universal joint is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of automotive parts, and particularly to a constant velocity universal joint and its ball cage. Background Art

[0002] As Figure 1 and Figure 2 shown, the constant velocity universal joint in the prior art includes an outer star wheel 100 with several (usually 6 or 8) equally spaced inner raceways distributed equally or designed with two types A and B staggered equally, an inner star wheel 200 with the same number of outer raceways and corresponding equally spaced distribution, a ball cage 300 (i.e., a cage) with the same number of equally spaced windows 301, and the same number of spheres 400. The spheres 400 are held in the windows 301 and cooperate with the outer raceway and the inner raceway at the same time. That is, the ball cage 300 restricts the movement of the spheres 400 within the central plane of the ball cage 300 itself.

[0003] When the constant velocity universal joint is in a swing angle condition of any non-zero degree, due to the existence of the raceway offset design, the raceways of the inner star wheel 200 or the outer star wheel 100 on the cross-section of the central plane of the ball cage 300 are no longer equally distributed, resulting in a rotational speed fluctuation of the spheres 400 around the center line of the ball cage 300 and a rotational speed difference with the ball cage 300. This will cause periodic contact and separation between the spheres 400 and the side walls 301a of the windows 301, and a large impact force is generated at the moment of contact. The impact force will cause the rotational speed of the ball cage 300 to increase, increasing the friction between the outer star wheel 100 and the ball cage 300, and between the ball cage 300 and the inner star wheel 200, and ultimately reducing the transmission efficiency of the constant velocity universal joint. Summary of the Invention

[0004] Aiming at the above defects, the purpose of the present invention is to provide a ball cage of a constant velocity universal joint, which helps to reduce the impact force between the spheres and the cage ribs, reduce the relative friction between the parts inside the constant velocity universal joint, and improve the transmission efficiency of the universal joint.

[0005] The present invention provides a ball cage of a constant velocity universal joint, including an annular cage body. The cage body has an outer surface and an inner surface. A plurality of windows are equally arranged along the circumferential direction of the cage body, and the windows communicate with the outer surface and the inner surface; along the circumferential direction of the cage body, the circumferential extension length L1 of the windows on the outer surface is less than the circumferential extension length L2 of the windows on the inner surface.

[0006] Preferably, the difference between L2 and L1 is 0.1 - 3 mm.

[0007] Preferably, the number of the windows is six or eight.

[0008] Preferably, side walls are formed on both sides of each window.

[0009] Preferably, the side wall is an inclined surface.

[0010] Preferably, the side wall is a curved surface.

[0011] The present invention also provides a constant velocity universal joint, which includes an outer star wheel with a plurality of inner raceways provided on its inner wall, an inner star wheel with a plurality of outer raceways provided on its outer wall, the aforementioned ball cage, and a plurality of balls. The inner star wheel is arranged inside the outer star wheel, the ball cage is arranged between the inner star wheel and the outer star wheel, the balls are located in the windows and are in contact and cooperation with the outer raceways and the inner raceways.

[0012] Preferably, the diameter of the ball is smaller than the circumferential extension length L1.

[0013] Preferably, the number of the inner raceways, the outer raceways and the balls are the same.

[0014] Preferably, the number of the windows is the same as the number of the balls, or is half of the number of the balls.

[0015] By improving the ball cage window structure, the present invention reduces the impact force between the ball and the window side wall, reduces the relative friction between the parts inside the constant velocity universal joint, and improves the transmission efficiency of the constant velocity universal joint. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a longitudinal sectional view of a conventional constant velocity universal joint;

[0017] Figure 2 is a cross-sectional view of a conventional constant velocity universal joint when the ball impacts the window side wall;

[0018] Figure 3 is a schematic diagram of the relative position between the ball and the outer star wheel when the ball impacts the window side wall in a conventional constant velocity universal joint;

[0019] Figure 4 is a cross-sectional view of a conventional ball cage;

[0020] Figure 5 (a) and (b) are schematic diagrams of two processing methods of a conventional ball cage;

[0021] Figure 6 is a cross-sectional view of the ball cage of the constant velocity universal joint of the present invention;

[0022] Figure 7 is a cross-sectional view of the constant velocity universal joint of the present invention when the ball impacts the window side wall;

[0023] Figure 8 is a schematic diagram of the relative position between the ball and the outer star wheel when the ball impacts the window side wall in the constant velocity universal joint of the present invention;

[0024] Figure 9 It is a relationship diagram of the phase where the sphere is located in the existing constant velocity joint and the impact force between the sphere and the side wall of the window;

[0025] Figure 10 It is a relationship diagram of the rotation angle and rotation speed of the existing constant velocity joint;

[0026] Figure 11 It is a relationship diagram of the phase where the sphere is located in the constant velocity joint of the present invention and the impact force between the sphere and the side wall of the window;

[0027] Figure 12 It is a relationship diagram of the rotation angle and rotation speed of the constant velocity joint of the present invention.

[0028] Explanation of component numbers:

[0029] 1 / 100 Outer star wheel

[0030] 2 / 200 Inner star wheel

[0031] 3 / 300 Constant velocity joint

[0032] 31 / 301 Window

[0033] 31a / 301a Side wall

[0034] 32 / 302 Outer surface

[0035] 33 / 303 Inner surface

[0036] 34 Cage body

[0037] 4 / 400 Sphere Detailed implementation manners

[0038] The following further elaborates in detail on the detailed implementation manners of the present invention in conjunction with the accompanying drawings. These implementation manners are only for illustrating the present invention and are not a limitation to the present invention.

[0039] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be construed as a limitation to the present invention.

[0040] In the description of the present invention, it should be noted that, unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0041] In addition, in the description of the present invention, unless otherwise stated, the meaning of "a plurality of" is two or more.

[0042] As Figure 6 shown, the present invention provides a constant velocity universal joint ball cage. The ball cage 3 includes a cage body 34 in a ring shape. The cage body 34 has an outer surface 32 and an inner surface 33 that are both spherical, and the inner surface 33 is located inside the outer surface 32. A plurality of windows 31 are equally circumferentially arranged along the cage body 34. The windows 31 communicate the outer surface 32 and the inner surface 33, and the windows 31 are used to limit the movement of the constant velocity universal joint spheres. Along the circumference of the cage body 34, on both sides of each window 31, side walls 31a are formed. The side walls 31a can be inclined surfaces extending along the axial direction of the cage body 34, or can be curved surfaces. Along the circumference of the cage body 34, the circumferential extension length L1 of the window 31 on the outer surface 32 is less than the circumferential extension length L2 of the window 31 on the inner surface 33. Specifically, the difference between L2 and L1 is 0.1 - 3 mm. The number of the windows 31 is preferably six or eight.

[0043] As Figure 7 shown, the present invention also provides a constant velocity universal joint, which includes an outer star wheel 1 provided with a plurality of inner ball tracks on its inner wall, an inner star wheel 2 provided with a plurality of outer ball tracks on its outer wall, the aforementioned ball cage 3, and a plurality of spheres 4. The inner star wheel 2 is arranged inside the outer star wheel 1, the ball cage 3 is arranged between the outer star wheel 1 and the inner star wheel 2, and each window 31 is provided with a sphere 4. Each sphere 4 is in contact and cooperation with the outer ball track and the inner ball track simultaneously. Wherein the outer surface 32 of the ball cage 3 is arranged on the side close to the outer star wheel 1, and the inner surface 33 is arranged on the side close to the inner star wheel 2. Since the spheres 4 need to be assembled under a sufficiently large swing angle, at this time, the unequal components of the inner and outer ball tracks on the central plane section of the ball cage 3 are very large. Therefore, the diameter of the spheres 4 is less than the circumferential extension length L1, so that there is a gap between the spheres 4 and the side walls 31a, providing a certain degree of freedom for the movement of the spheres 4. The number of the inner ball tracks, the outer ball tracks, and the spheres 4 are the same. The number of the windows 31 is the same as the number of the spheres 4, or is half of the number of the spheres 4, that is, one or two spheres 4 are placed in each window 31.

[0044] As Figure 4 and Figure 5As shown, the window 301 of the existing constant velocity joint 300 is formed by stamping as shown in Figure 5 (a) or by milling as shown in Figure 5 (b). The circumferential extension length L3 of the obtained window 301 on the outer surface 302 is greater than or equal to the circumferential extension length L4 of the window 301 on the inner surface 303. As shown in Figure 2 、 Figure 3 、 Figure 9 and Figure 10 shown, the 12 o'clock position of the outer star wheel 100 is defined as the 0° phase. When any sphere 400 moves to around the 120° phase (i.e., rotates 120° counterclockwise from the 0° phase) and reaches the bottom position of the outer star wheel 100, a relatively large impact force is generated when the sphere 400 contacts and collides with the side wall 301a. As shown in Figure 7 、 Figure 8 、 Figure 11 and Figure 12 shown, in the constant velocity joint 3 of the present invention, when the sphere 4 moves to around the 300° phase (i.e., rotates 300° counterclockwise from the 0° phase) and reaches the mouth position of the outer star wheel 1, a relatively small impact force is generated when the sphere 4 contacts and collides with the side wall 31a. Under the same working conditions (loading torque 200 Nm, constant rotation speed 900 deg / s), the maximum impact force generated by using the existing constant velocity joint of a certain fixed joint is 620 N, and the rotation speed of the existing constant velocity joint is 850 - 930 deg / s; after using the constant velocity joint of the present invention, the maximum impact force is reduced to 275 N, and the rotation speed of the constant velocity joint of the present invention is 890 - 910 deg / s.

[0045] As can be seen from the above, the sphere in the existing constant velocity joint contacts and collides with the side wall at around the 120° phase, generating a relatively large impact force. The relatively large impact force has a large accelerating effect on the constant velocity joint, increasing the friction between the outer star wheel and the constant velocity joint, and between the constant velocity joint and the inner star wheel, ultimately reducing the transmission efficiency of the constant velocity universal joint. By improving the window structure of the constant velocity joint, the present invention changes the impact moment of the sphere and the side wall. The sphere contacts and collides with the side wall at around the 300° phase, generating an impact force smaller than the prior art, thereby improving the abnormal noise problem of the constant velocity universal joint caused by impact; at the same time, the relatively small impact force has a small accelerating effect on the constant velocity joint, reducing the relative friction between the outer star wheel and the constant velocity joint, and between the constant velocity joint and the inner star wheel, and thus improving the transmission efficiency of the constant velocity universal joint.

[0046] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and substitutions can be made, and these improvements and substitutions should also be regarded as the protection scope of the present invention.

Claims

1. A constant velocity universal joint ball cage, characterized in that, It includes a cage body (34) in a ring shape. The cage body (34) has an outer surface (32) and an inner surface (33). A plurality of windows (31) are equidistantly arranged along the circumferential direction of the cage body (34). The windows (31) communicate the outer surface (32) and the inner surface (33). Along the circumferential direction of the cage body (34), the circumferential extension length L1 of the window (31) on the outer surface (32) is less than the circumferential extension length L2 of the window (31) on the inner surface (33).

2. The constant velocity universal joint ball cage according to claim 1, characterized in that, The difference between L2 and L1 is 0.1 - 3 mm.

3. The constant velocity joint ball cage according to claim 1, characterized in that, The number of the windows (31) is six or eight.

4. The constant velocity joint ball cage according to claim 1, characterized in that, Side walls (31a) are formed on both sides of each window (31).

5. The constant velocity universal joint ball cage according to claim 4, characterized in that, The side walls (31a) are inclined planes.

6. The constant velocity joint ball cage according to claim 4, characterized in that, The side walls (31a) are curved surfaces.

7. A constant velocity universal joint, characterized in that, It includes an outer star wheel (1) with a plurality of inner raceways provided on the inner wall, an inner star wheel (2) with a plurality of outer raceways provided on the outer wall, a constant velocity joint (3) according to any one of claims 1 - 6, and a plurality of spheres (4). The inner star wheel (2) is arranged inside the outer star wheel (1). The constant velocity joint (3) is arranged between the inner star wheel (1) and the outer star wheel (2). The spheres (4) are located in the windows (31) and are in contact and cooperation with the outer raceways and the inner raceways.

8. The constant velocity universal joint according to claim 7, characterized in that, The diameter of the sphere (4) is less than the circumferential extension length L1.

9. The constant velocity universal joint according to claim 7, characterized in that, The numbers of the inner raceways, the outer raceways and the spheres (4) are the same.

10. The constant velocity universal joint according to claim 9, characterized in that, The number of the windows (31) is the same as the number of the spheres (4), or is half of the number of the spheres (4).

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