Constant velocity universal joint with steel ball and ball cage rotating synchronously, transmission system and electric automobile

Abstract

The invention relates to a constant velocity universal joint with a steel ball and a ball cage rotating synchronously, a transmission system and an electric automobile. The constant velocity universal joint comprises an outer star wheel, a ball cage and an inner star wheel, a plurality of inner ball grooves are equally distributed in the outer star wheel, a plurality of outer ball grooves are correspondingly and equally distributed outside the inner star wheel, the inner ball grooves and the outer ball grooves form a plurality of ball grooves in a one-to-one correspondence mode, a plurality of windows are equally distributed in the ball cage, and a steel ball is contained in each window. Each steel ball is in contact fit with one ball groove, one or a pair of symmetrically-arranged ball grooves are concentric ball grooves, the steel balls in the concentric ball grooves are concentrically contained in the windows, the width of the windows corresponding to the steel balls in the concentric ball grooves is matched with the diameter of the steel balls, and the other ball grooves are eccentric ball grooves. And the width of the window corresponding to the steel ball in the eccentric ball channel is greater than or equal to 2 * (steel ball diameter / 2 + assembly compensation clearance value). The constant velocity universal joint can eliminate abnormal sound and improve abnormal wear.

Description

Technical Field

[0001] The invention relates to the technical field of constant velocity universal joints, and in particular to a constant velocity universal joint with a steel ball and a ball cage rotating synchronously, a transmission system using the constant velocity universal joint, and an electric vehicle using the transmission system. Background Art

[0002] See also Figure 1 The constant velocity universal joint is mainly composed of an outer star wheel 1 on the outside, a ball cage 2 in the middle and an inner star wheel 3 on the inside. The inner spherical surface of the outer star wheel 1 is evenly distributed with a number of inner ball tracks 101, and the outer spherical surface of the inner star wheel 3 is evenly distributed with a number of outer ball tracks 301. The inner ball tracks 101 and the outer ball tracks 301 correspond to each other to form a number of ball tracks 4. The ball cage 2 is evenly distributed with a number of windows 201, each window 201 contains a steel ball 5, and each steel ball 5 is in contact with a ball track 4.

[0003] However, due to the existence of the ballway offset design on the existing constant velocity universal joint, see Figure 2 When the constant velocity joint is in any swing angle condition other than 0°, the distribution of the ball track 4 on the center plane section of the ball cage 2 will no longer have an equally distributed characteristic, and the unequal components of the ball track 4 on the center plane section of the ball cage 2 will be very large, which means that in order to enable the steel ball 5 to be assembled at a sufficiently large swing angle, the width of the window 201 on the ball cage 2 must be much larger than the diameter of the steel ball 5, which results in the steel ball 5 having a large degree of freedom of movement in the window 201 of the ball cage 2; therefore, during the rotation process of the constant velocity joint with a swing angle ≠ 0°, the steel ball 5 is accelerated and decelerated relative to the window 201 of the ball cage 2, resulting in a circumferential relative rotation between the steel ball 5 and the window 201 of the ball cage 2 and friction marks.

[0004] The inherent disadvantages of the above-mentioned traditional constant velocity joints will play a negative role in specific working conditions: 1. The acceleration and deceleration between the steel ball and the ball cage cause the steel ball and the side of the ball cage window to periodically contact and disengage, and a large impact force is generated at the moment of contact to form a vibration signal, which is easily transmitted to the cockpit by the vehicle suspension, especially in a relatively quiet driving space such as an electric vehicle, where the passengers can easily perceive the abnormal noise, affecting the riding comfort; 2. The ball cage has a large circumferential degree of freedom in the constant velocity joint. When the constant velocity joint is forced to bear the impact due to the change of the constant velocity joint angle, the sudden change of the torque transmission direction, the rapid acceleration and deceleration of the vehicle, etc., the relative position of the steel ball and the ball cage window changes rapidly, the relative movement between the parts in the joint increases, and it is easy to cause the wear in the joint to increase. Especially for electric vehicles with energy recovery function, due to the frequent changes in the torque transmission direction and the very high negative torque, abnormal wear in the constant velocity joint often occurs. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a constant velocity universal joint capable of eliminating abnormal noise, improving abnormal wear, and synchronously rotating steel balls and ball cages.

[0006] The present invention adopts the following technical solution:

[0007] The present invention provides a constant velocity universal joint in which a steel ball and a ball cage rotate synchronously, comprising an outer star wheel on the outside, a ball cage in the middle and an inner star wheel on the inside, wherein a plurality of inner ball paths are equally distributed on the inner spherical surface of the outer star wheel, a plurality of outer ball paths are correspondingly equally distributed on the outer spherical surface of the inner star wheel, and the inner ball paths and the outer ball paths correspond to each other to form a plurality of ball paths, and a plurality of windows are equally distributed on the ball cage, each window contains a steel ball, and each steel ball is in contact with a ball path respectively, wherein one or a pair of symmetrically arranged ball paths are concentric ball paths, The inner ballway and the outer ballway on the concentric ballway are concentric with the corresponding inner spherical surface of the outer star wheel and the outer spherical surface of the inner star wheel respectively. The steel ball in the concentric ballway is concentrically accommodated in the window, and the width of the window corresponding to the steel ball in the concentric ballway matches the diameter of the steel ball. The remaining ballways are eccentric ballways. The inner ballway and the outer ballway on the eccentric ballway are offset from the corresponding inner spherical surface of the outer star wheel and the outer spherical surface of the inner star wheel respectively. The width of the window corresponding to the steel ball in the eccentric ballway is ≥2×(steel ball diameter / 2+assembly compensation clearance value).

[0008] Preferably, the length design dimensions of the window corresponding to the steel ball in the concentric ball channel and the window corresponding to the steel ball in the eccentric ball channel for the contact area with the steel ball are equal.

[0009] Preferably, the inner ball track and the outer ball track on the concentric ball track are both single arc segments with an extended length that meets the swing angle requirement of the constant velocity universal joint.

[0010] Preferably, the ball cage is processed by stamping to form a window with a width matching the diameter of the steel ball.

[0011] The present invention also provides a transmission system, which adopts any of the above-mentioned constant velocity universal joints in which the steel balls and the ball cage rotate synchronously.

[0012] The present invention also provides an electric vehicle which adopts the transmission system mentioned above.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] The constant velocity universal joint with synchronous rotation of the steel ball and the ball cage of the present invention makes one or a pair of symmetrically arranged ball paths a concentric ball path, the steel ball in the concentric ball path is concentrically accommodated in the window, and the width of the window corresponding to the steel ball in the concentric ball path matches the diameter of the steel ball, so that the synchronous rotation of the steel ball and the ball cage can be achieved, and the collision or knocking between the ball cage and the steel ball caused by rapid acceleration and deceleration between the two can be completely avoided, and the NVH problem of the whole vehicle can be prevented; at the same time, the synchronous rotation of the steel ball and the ball cage can also reduce the friction and wear caused by the rapid relative movement of the parts in the synchronous universal joint, thereby reducing the risk of the life of the constant velocity universal joint. In addition, the width of the window corresponding to the steel ball in the concentric ball path matches the diameter of the steel ball, which substantially increases the window rib area of ​​the ball cage, which is conducive to improving the strength of the ball cage itself.

[0015] The transmission system and the electric vehicle of the present invention both include the constant velocity universal joint in which the steel balls and the ball cage rotate synchronously, and naturally have the above-mentioned beneficial effects, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the radial section structure of a traditional constant velocity universal joint in the background technology.

[0017] Figure 2 It is a structural schematic diagram of a traditional constant velocity universal joint cut along the center plane of the ball cage at a non-0° swing angle in the background technology.

[0018] Figure 3 The present invention is a schematic structural diagram of a constant velocity universal joint in which a steel ball and a ball cage rotate synchronously, which is radially sectioned along a pair of symmetrically arranged concentric ball paths.

[0019] Figure 4 It is a schematic structural diagram of a constant velocity universal joint in which a steel ball and a ball cage rotate synchronously, cut radially along a pair of symmetrically arranged concentric ball paths at a non-0° swing angle in an embodiment of the present invention.

[0020] Figure 5 It is a schematic structural diagram of a constant velocity universal joint in which a steel ball and a ball cage rotate synchronously, cut along the center plane of the ball cage at a non-0° swing angle in an embodiment of the present invention.

[0021] Figure 6 The present invention is a schematic diagram of the force exerted by the steel ball on the ball cage in the eccentric ball track at a fixed swing angle in a constant velocity universal joint in which the steel ball and the ball cage rotate synchronously.

[0022] Figure 7 The invention is a schematic diagram of the movement direction of the steel ball in the concentric ball track under the variable swing angle of the constant velocity universal joint in which the steel ball and the ball cage rotate synchronously.

[0023] The reference numerals are described as follows:

[0024] 1. Outer star wheel 3. Inner star wheel

[0025] 101, inner fairway 301, outer fairway

[0026] 2. Cage 4. Ballway

[0027] 201, Window 5, Steel Ball DETAILED DESCRIPTION

[0028] The specific embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. These embodiments are only used to illustrate the present invention, but not to limit the present invention.

[0029] In the description of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0030] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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 mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] Furthermore, in the description of the present invention, unless otherwise specified, “plurality” means two or more.

[0032] See also Figure 3The present embodiment provides a constant velocity universal joint in which a steel ball and a ball cage rotate synchronously, comprising an outer star wheel 1 on the outside, a ball cage 2 in the middle and an inner star wheel 3 on the inside, the inner spherical surface of the outer star wheel 1 is evenly distributed with a plurality of inner ball tracks 101, the outer spherical surface of the inner star wheel 3 is evenly distributed with a plurality of outer ball tracks 301, the inner ball tracks 101 and the outer ball tracks 301 correspond to each other to form a plurality of ball tracks 4, the ball cage 2 is evenly distributed with a plurality of windows 201, each window 201 contains a steel ball 5, each steel ball 5 is in contact with a ball track 4, and one or a pair of symmetrically arranged ball tracks 4 are concentric. The inner ballway 101 and the outer ballway 301 on the concentric ballway are respectively concentric with the corresponding inner spherical surface of the outer star wheel and the outer spherical surface of the inner star wheel, the steel ball 5 in the concentric ballway is concentrically accommodated in the window 201, and the width of the window 201 corresponding to the steel ball 5 in the concentric ballway matches the diameter of the steel ball 5, and the remaining ballways are eccentric ballways, and the inner ballway 101 and the outer ballway 301 on the eccentric ballway are respectively offset from the corresponding inner spherical surface of the outer star wheel and the outer spherical surface of the inner star wheel, and the width of the window 201 corresponding to the steel ball 5 in the eccentric ballway is ≥2×(steel ball diameter / 2+assembly compensation clearance value).

[0033] In the constant velocity universal joint of this embodiment, the concentric ball track lacks the constraint of the swing angle direction in structure because the inner ball track 101 and the outer ball track 301 of the concentric ball track are cocentric with the inner spherical surface of the corresponding outer star wheel and the outer spherical surface of the inner star wheel respectively. The angle between the tangent of the steel ball 5 and the inner ball track 101 and the tangent of the steel ball 5 and the outer ball track 301 is 0°, and thus has the following inherent characteristics:

[0034] 1. No positive pressure is provided between the steel ball 5 and the window 201. Figure 4 When the constant velocity universal joint is in the process of rotating at any swing angle, the contact points of the inner ball track 101 and the outer ball track 301 of the concentric ball track with the steel ball 5 are all on the central plane of the ball cage 2, and the horizontal force is 0, that is, no positive pressure is provided to the side of the window of the ball cage 2. At this time, in the eccentric ball track, the steel ball 5 provides positive pressure to the side of the window of the ball cage 2 near the outer star wheel bowl, while in the concentric ball track (under the influence of the positive pressure of the steel ball in the eccentric ball track), the window of the ball cage 2 near the bottom of the outer star wheel bowl provides positive pressure to the steel ball 5.

[0035] 2. The circumferential compensation of the center of the steel ball is almost zero. Figure 5 The steel ball 5 in the concentric ball track is concentric with the window 201, and there is only a tiny gap between the diameter of the steel ball 5 and the width of the corresponding window 201 for the steel ball 5 to rotate freely. The circumferential offset generated at any phase of each swing angle is very small, almost zero.

[0036] 3. The force between the steel ball 5 in the concentric ballway and the inner and outer star wheels is basically the same as the force between the steel ball 5 in the eccentric ballway and the inner and outer star wheels. In particular, in the constant velocity universal joint, the maximum magnitude of the force exerted by the concentric ballway and the eccentric ballway on their respective steel balls 5 is equivalent, and therefore the ballway force and related stress have no negative impact, and will not produce adverse effects on the force in the constant velocity universal joint.

[0037] Based on the above inherent characteristics, the acting force between each steel ball 5 and the inner and outer star wheels in the constant velocity universal joint of this embodiment is a periodic fluctuation. After one or a pair of ball paths 4 are designed as concentric ball paths, there will be no interference, overload and instability problems in the constant velocity universal joint; in addition, the width of the window 201 corresponding to the steel ball 5 in the concentric ball path matches the diameter of the steel ball 5, so the steel ball 5 and the cage 2 in the concentric ball path have the characteristics of synchronous rotation. During the rotation of the constant velocity universal joint, the circumferential compensation of the steel ball 5 in the concentric ball path is almost zero, the steel ball 5 and the cage 2 constrain each other, and the rotation speed of the cage 2 is completely equal to the rotation speed of the steel ball 5 around the center line of the cage. Thanks to the fact that the rotation speed of the cage is completely restricted by the structure, there will be no unfavorable working conditions such as rapid acceleration and deceleration of the cage.

[0038] On the other hand, the width of the window 201 corresponding to the steel ball 5 in the eccentric ball channel is ≥ 2×(steel ball diameter / 2+assembly compensation clearance value), and its width retains the original design features to meet the assemblability of the structure. During the rotation of the constant velocity universal joint, the steel ball 5 in the eccentric ball channel rotates in the "8" shape in its corresponding window 201. Since the ball cage 2 rotates synchronously with the steel ball 5 in the concentric ball channel, the steel ball 5 in the eccentric ball channel will never collide with the side of the window to generate an impact signal, and more and worse working conditions of rapid movement between the parts in the constant velocity universal joint will not be generated.

[0039] Preferably, in this embodiment, although only one concentric ball track can realize the synchronous rotation of the steel ball 5 and the ball cage 2, it is not as good as setting a pair of symmetrically arranged concentric ball tracks in terms of internal load stability, manufacturing cost, process control, etc. of the constant velocity universal joint. Therefore, in actual use, setting a pair of symmetrically arranged concentric ball tracks is the optimal solution.

[0040] It should be noted that when assembling the constant velocity universal joint in which the steel balls and the ball cage rotate synchronously in this embodiment, the steel balls in the eccentric ball track are assembled first. When the steel balls in the concentric ball track are assembled later, no additional circumferential compensation is required for the steel balls in the eccentric ball track, which will not lead to an increase in the circumferential space requirement for the window 201 of the ball cage 2 and will not affect its assemblability.

[0041] Preferably, the lengths of the windows 201 corresponding to the steel ball 5 in the concentric ball lane and the lengths of the windows 201 corresponding to the steel ball 5 in the eccentric ball lane used for contacting the steel ball are designed to be equal.

[0042] Preferably, see Figure 3 and Figure 4 The inner ball track 101 and the outer ball track 301 on the concentric ball track are both single arc segments with extended lengths that meet the swing angle requirements of the constant velocity universal joint.

[0043] Preferably, the cage 2 is punched to form a window 201 with a width matching the diameter of the steel ball.

[0044] See also Figure 6 In the constant velocity universal joint of the embodiment, the steel ball and the cage rotate synchronously. Under any fixed swing angle, the steel ball 5 in the eccentric ball channel always applies positive pressure to the window 201 of the cage 2 during the reciprocating motion in its ball channel, eliminating the freedom of the cage's flipping direction, so that the cage's center plane is always on the plane that divides the gap between the inner and outer star wheel center planes, and basically no deflection occurs. Furthermore, the cage 2 constrains the steel ball 5 in the concentric ball channel to the cage's center plane, so that the steel ball 5 also performs complete and coherent reciprocating motion in its own ball channel. See Figure 7 When the constant velocity universal joint is in a variable swing angle, the steel balls 5 in the eccentric ballway are squeezed by the inner and outer star wheels to push the cage 2 to the equally divided plane of the inner and outer star wheels to form a constant speed, while the steel balls 5 in the concentric ballway swing along the center plane of the cage. Obviously, no matter it is a fixed swing angle or a variable swing angle, the speed of the cage 2 rotating around the center is always consistent with the steel balls 5 in the concentric ballway.

[0045] This embodiment also provides a transmission system, which adopts the above-mentioned constant velocity universal joint in which the steel balls and the ball cage rotate synchronously.

[0046] This embodiment also provides an electric vehicle, which adopts the above-mentioned transmission system.

[0047] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A constant velocity universal joint in which a steel ball and a ball cage rotate synchronously, comprising an outer star wheel (1) on the outside, a ball cage (2) in the middle and an inner star wheel (3) on the inside, wherein the inner spherical surface of the outer star wheel (1) is evenly distributed with a plurality of inner ball tracks (101), the outer spherical surface of the inner star wheel (3) is evenly distributed with a plurality of outer ball tracks (301), the inner ball tracks (101) and the outer ball tracks (301) form a plurality of ball tracks (4) in one-to-one correspondence, the ball cage (2) is evenly distributed with a plurality of windows (201), each of the windows (201) contains a steel ball (5), and each of the steel balls (5) is in contact with and cooperates with one of the ball tracks (4), characterized in that: One or a pair of symmetrically arranged ball paths (4) are concentric ball paths, and the inner ball path (101) and the outer ball path (301) on the concentric ball paths are concentric with the corresponding inner spherical surface of the outer star wheel and the outer spherical surface of the inner star wheel, respectively. The steel ball (5) in the concentric ball path is concentrically accommodated in the window (201), and the width of the window (201) corresponding to the steel ball (5) in the concentric ball path matches the diameter of the steel ball (5). The remaining ball paths are eccentric ball paths, and the inner ball path (101) and the outer ball path (301) on the eccentric ball paths are offset from the corresponding inner spherical surface of the outer star wheel and the outer spherical surface of the inner star wheel, respectively. The width of the window (201) corresponding to the steel ball (5) in the eccentric ball path is ≥2×(steel ball diameter / 2+assembly compensation clearance value).

2. The constant velocity universal joint with synchronous rotation of the steel ball and the ball cage according to claim 1, characterized in that: The window (201) corresponding to the steel ball (5) in the concentric ball path and the window (201) corresponding to the steel ball (5) in the eccentric ball path are designed to have the same length dimensions for the contact area with the steel ball (5).

3. The constant velocity universal joint with synchronous rotation of the steel ball and the ball cage according to claim 1, characterized in that: The inner ball track (101) and the outer ball track (301) on the concentric ball track are both single arc segments with an extended length that meets the swing angle requirements of the constant velocity universal joint.

4. The constant velocity universal joint with synchronous rotation of the steel ball and the ball cage according to claim 1, characterized in that: The ball cage (2) is processed by stamping to form a window (201) with a width matching the diameter of the steel ball.

5. A transmission system, characterized in that: A constant velocity universal joint in which the steel ball and the ball cage rotate synchronously is adopted as described in any one of claims 1 to 4.

6. An electric vehicle, characterized in that: The transmission system according to claim 5 is adopted.

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