A constant velocity universal joint and a method for eliminating knocking noise from the constant velocity universal joint

Abstract

This invention provides a constant velocity universal joint and a method for eliminating knocking noise from the constant velocity universal joint. The joint includes an outer star wheel, an inner star wheel, a ball cage, and several steel balls. The inner wall of the outer star wheel has several equally spaced inner ball tracks, and the outer wall of the inner star wheel has several equally spaced outer ball tracks. The ball cage has several equally spaced windows. The ball cage is positioned between the inner and outer star wheels, and the inner ball tracks, windows, and outer ball tracks are aligned. Several steel balls are positioned between the inner ball tracks, windows, and outer ball tracks. Any window or any pair of windows symmetrically distributed relative to the center of the ball cage is designated as a limiting window, and the remaining windows are non-limiting windows. When the constant velocity universal joint rotates, the steel ball in the limiting window contacts the inner wall of the limiting window, while the steel balls in the non-limiting windows do not contact the inner wall of the non-limiting windows. This invention fundamentally and completely avoids knocking noise from the steel balls and the windows on one side of the ball cage along their length, thus providing a method to thoroughly eliminate knocking noise from constant velocity universal joints.

Description

Technical Field

[0001] This invention relates to the field of automotive transmission equipment technology, and in particular to a constant velocity universal joint and a method for eliminating knocking noise from the constant velocity universal joint. Background Technology

[0002] like Figure 1 As shown, the existing constant velocity universal joint consists of an outer star wheel 2 with several equally divided inner ball tracks, an inner star wheel 1 with the same number of equally divided outer ball tracks, a ball cage 3 with the same number of equally divided windows, and the same number of steel balls 4. The steel balls 4 are housed within the windows of the ball cage 3, and the ball cage 3 constrains the steel balls 4 to move within its central plane.

[0003] like Figure 2 , Figure 3 As shown, when the constant velocity universal joint is in a large angle working condition, the distribution of the ball track on the central plane section of the ball cage 3 by the inner star wheel 1 and the outer star wheel 2 is no longer equally distributed, causing the rotation speed of the steel ball 4 around the center line of the ball cage 3 to fluctuate, and generating a rotation speed difference with the synchronously rotating ball cage 3.

[0004] like Figure 4 As shown, when the ball cage 3 is pushed by the friction of the inner star wheel 1 and the outer star wheel 2, causing the steel ball 4 to contact one side of the window along the length direction of the ball cage 3, the difference in rotational speed between the steel ball 4 and the ball cage 3 causes each steel ball 4 to periodically contact and detach from one side of the window along the length direction during rotation. A large impact force is generated at the moment of contact, forming a periodic knocking vibration signal. This knocking vibration signal is usually perceived by vehicle occupants as knocking noise, seriously affecting vehicle comfort.

[0005] The knocking vibration and the resulting knocking noise caused by the difference in relative rotational speed between the steel ball and the ball cage under large-angle working conditions (usually when the vehicle is turning at a small radius, in which case the working angle of the constant velocity universal joint can be greater than 35°) are inherent undesirable characteristics of the existing structure of the constant velocity universal joint.

[0006] In traditional gasoline-powered vehicles, the knocking noise from constant velocity joints is easily masked by the engine noise and thus difficult to perceive. However, with the development and widespread adoption of electric vehicles, the superior quietness of these vehicles makes the knocking noise from the universal joints increasingly noticeable to drivers and passengers. Therefore, eliminating the knocking vibration of the universal joint and the resulting noise has become a pressing design challenge. Summary of the Invention

[0007] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a constant velocity universal joint and a method for eliminating knocking noise from the constant velocity universal joint, so as to solve the negative impact caused by periodic knocking on one side of the steel ball and the cage window along the length direction in the prior art.

[0008] To achieve the above and other related objectives, the present invention provides a constant velocity universal joint, comprising an outer star wheel, an inner star wheel, a ball cage, and a plurality of steel balls. The inner wall of the outer star wheel is provided with a plurality of equally spaced inner ball tracks, and the outer wall of the inner star wheel is provided with a plurality of equally spaced outer ball tracks. The ball cage is provided with a plurality of equally spaced windows. The ball cage is positioned between the inner and outer star wheels, and the inner ball tracks, windows, and outer ball tracks are aligned. A plurality of steel balls are positioned between the inner ball tracks, windows, and outer ball tracks. Any window or any pair of windows symmetrically distributed relative to the center of the ball cage is designated as a limiting window, and the remaining windows are non-limiting windows. When the constant velocity universal joint rotates, the steel ball in the limiting window contacts the inner wall of the limiting window, while the steel ball in the non-limiting window does not contact the inner wall of the non-limiting window.

[0009] Preferably, the length of the non-limiting window is L, the diameter of the steel ball is D, the width of the non-limiting window matches the diameter of the steel ball, and the length direction motion degree of the steel ball in the non-limiting window is L0=LD; the length of the limiting window is L1, and the length direction motion degree of the steel ball in the limiting window is a=L1-D; the value of a is 0≤a≤0.3L0.

[0010] Preferably, when L1=D, the length direction motion degree of the steel ball in the limiting window is a=0; the steel ball and the cage in the limiting window rotate synchronously, and the length direction motion degree of the steel ball in the non-limiting window and the inner wall of the non-limiting window is L0.

[0011] Preferably, when L1 = L - 0.7L0, the length direction motion degree of the steel ball in the limiting window is a = 0.3L0. After the steel ball in the limiting window comes into contact with the inner wall of the cage, the steel ball in the limiting window and the cage move synchronously. The length direction motion degree of the steel ball in the non-limiting window and the inner wall of the non-limiting window is 0.7L0.

[0012] Preferably, the width of the limiting window is smaller than the diameter of the steel ball, and the limiting window has a limiting groove along its width extension direction. The sum of the groove depth and the width of the limiting window matches the diameter of the steel ball. The steel ball is engaged in the limiting groove, and the steel ball is completely in contact with the inner wall of the limiting groove. The steel ball in the limiting window and the ball cage rotate synchronously, and the length direction motion degree of freedom between the steel ball in the non-limiting window and the inner wall of the non-limiting window is L0.

[0013] Preferably, the width of the limiting window is smaller than the diameter of the steel ball, and a limiting groove is formed in the limiting window along the width extension direction. The sum of the groove depth and the width of the limiting window matches the diameter of the steel ball. The steel ball is engaged in the limiting groove and can move along the length direction of the limiting window within the limiting groove. The length direction motion degree of the steel ball in the limiting groove is a = 0.3L0. After the steel ball in the limiting window abuts against the inner wall of the limiting groove, the steel ball in the limiting window and the ball cage move synchronously. The length direction motion degree of the steel ball in the non-limiting window is 0.7L0.

[0014] To achieve the above or other objectives, the present invention also discloses a method for eliminating knocking noise in constant velocity universal joints. Addressing the problem of abnormal noise generated by constant velocity universal joints during operation, the steps are as follows:

[0015] S1: Select any window or any pair of windows symmetrically distributed relative to the center of the ball cage as a restricted window, and the remaining windows are unrestricted windows; the length of the unrestricted window is L, the diameter of the steel ball is D, and the degree of freedom of the steel ball in the length direction in the unrestricted window is L0=LD;

[0016] The length of the limiting window is L1; the length direction of the steel ball within the limiting window has a degree of freedom.

[0017] S2: The length L1 of the limiting window, the width of the limiting window, and whether the limiting window has a limiting groove are designed so that when the steel ball in the limiting window abuts against the inner wall of the limiting window, the steel ball in the non-limiting window does not abut against the inner wall of the non-limiting window.

[0018] S3: Then install the inner star wheel, outer star wheel, ball cage, and steel balls; when installing the steel balls, install the steel balls in the non-limiting window first, and install the steel balls in the limiting window as the last one or the last two.

[0019] Preferably, in step S2, the width of the limiting window is greater than the diameter of the steel ball, and the length of the limiting window is D≤L1≤L-0.7L0.

[0020] Preferably, in step S2, the width of the limiting window is smaller than the diameter of the steel ball, and a limiting groove is formed in the limiting window; the steel ball is stuck in the limiting groove and the steel ball is completely in contact with the inner wall of the limiting groove, and the degree of freedom of the steel ball in the longitudinal direction in the limiting groove is a=0; or the steel ball moves in the limiting groove along the longitudinal direction of the limiting window, and the degree of freedom of the steel ball in the longitudinal direction in the limiting groove is 0<a≤0.3L0.

[0021] As described above, the constant velocity universal joint and the method for eliminating knocking noise of the constant velocity universal joint involved in this invention have the following beneficial effects:

[0022] In this invention, the window is divided into a limiting window and a non-limiting window. The limiting window is designed in a certain way to reduce the degree of freedom of the steel ball. When the ball cage is pushed by the friction of the inner and outer star wheels to make the steel ball contact one side of the window length direction, the steel ball in the limiting window contacts the side of the limiting window length direction first. At this time, the steel ball in the non-limiting window will not contact the side of the non-limiting window length direction, thereby completely eliminating the knocking vibration of the steel ball in the non-limiting window. This fundamentally and completely avoids the knocking of the steel ball and the side of the window length direction on the ball cage, and is a method to completely eliminate the knocking noise of the constant velocity universal joint. Attached Figure Description

[0023] Figure 1 This is a structural diagram of a conventional medium-speed universal joint.

[0024] Figure 2 , Figure 3 This is a schematic diagram showing the relative state of the steel ball and the window when the medium-speed universal joint rotates in the existing technology.

[0025] Figure 4 This is a schematic diagram of the vibration signal of a medium-speed universal joint in the prior art;

[0026] Figure 5 This is a cross-sectional view of the constant velocity universal joint involved in the present invention.

[0027] Figure 6 This is a schematic diagram of the first embodiment of the constant velocity universal joint involved in the present invention;

[0028] Figure 7 This is a schematic diagram of the second embodiment of the constant velocity universal joint involved in the present invention;

[0029] Figure 8 This is a schematic diagram of the third embodiment of the constant velocity universal joint involved in the present invention;

[0030] Figure 9 This is a schematic diagram of the fourth embodiment of the constant velocity universal joint involved in the present invention;

[0031] Figure 10 This is a spatial schematic diagram of the constant velocity universal joint involved in the present invention.

[0032] Explanation of reference numerals in the attached figures:

[0033] 1. Inner star wheel; 2. Outer star wheel; 3. Ball cage; 301. Limit window; 302. Non-limit window; 303. Limit groove; 4. Steel ball. Detailed Implementation

[0034] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0035] It should be understood that the structures, proportions, sizes, etc., illustrated in the accompanying drawings of this specification are merely for illustrative purposes to aid those skilled in the art and are not intended to limit the scope of the invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the technical content disclosed in this invention. Furthermore, the terms such as "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and are not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention's implementation.

[0036] like Figures 5-10 As shown, the present invention provides a constant velocity universal joint, including an outer star wheel 2, an inner star wheel 1, a ball cage 3, and a plurality of steel balls 4. The inner wall of the outer star wheel 2 is equally spaced with a plurality of inner ball tracks, the outer wall of the inner star wheel 1 is equally spaced with a plurality of outer ball tracks, and the ball cage 3 is equally spaced with a plurality of windows. The ball cage 3 is positioned between the inner star wheel 1 and the outer star wheel 2. The number of inner ball tracks, windows, and outer ball tracks are equal and aligned with each other. The plurality of steel balls 4 are positioned between the inner ball tracks, windows, and outer ball tracks. Any window or any pair of windows symmetrically distributed relative to the center of the ball cage 3 is designated as a limiting window 301, and the remaining windows are non-limiting windows 302. When the constant velocity universal joint rotates, the steel ball 4 in the limiting window 301 contacts the inner wall of the limiting window 301, the steel ball 4 in the non-limiting window 302 will not contact the inner wall of the non-limiting window 302.

[0037] The constant velocity universal joint of the present invention selects one or two symmetrically distributed windows as limiting windows 301, and the remaining windows are non-limiting windows 302. By changing the length and width of the limiting window 301 and setting the limiting groove 303, when the constant velocity universal joint rotates, the steel ball 4 in the limiting window 301 first abuts against the inner wall of the limiting window 301, and the steel ball 4 in the non-limiting window 302 does not abut against the inner wall of the non-limiting window 302. Therefore, the knocking vibration caused by the collision between the steel ball 4 in the non-limiting window 302 and the inner wall of the non-limiting window 302 is completely eliminated, and the knocking noise of the constant velocity universal joint is fundamentally eliminated.

[0038] like Figure 5 , Figure 7As shown, the length of the non-restricted window 302 is L, the diameter of the steel ball 4 is D, and the width of the non-restricted window 302 matches the diameter of the steel ball 4. The length direction freedom of the steel ball 4 in the non-restricted window 302 is L0 = LD. The length of the restricted window 301 is L1, and the length direction freedom of the steel ball 4 in the restricted window 301 is a = L1 - D. The value of a ranges from 0 ≤ a ≤ 0.3L0. The number of steel balls 4 is set to six or eight; this application uses six steel balls 4 for detailed description. L is greater than D, thus ensuring that the steel balls 4 can be assembled into the window.

[0039] The application involves the following embodiments:

[0040] First embodiment:

[0041] like Figure 5 , Figure 6 As shown, when L1=D, the length direction motion degree of freedom of the steel ball 4 in the limiting window 301 is a=0; the steel ball 4 in the limiting window 301 and the ball cage 3 rotate synchronously, and the length direction motion degree of freedom between the steel ball 4 in the non-limiting window 302 and the inner wall of the non-limiting window 302 is L0. In this embodiment, since the length of the limiting window 301 matches the diameter of the steel ball 4, that is, the steel ball 4 is fixedly stuck in the limiting window 301, the steel ball 4 in the limiting window 301 rotates synchronously with the ball cage 3, and the length direction motion degree of freedom between the steel ball 4 in the non-limiting window 302 and the inner wall of the non-limiting window 302 is always L0, no knocking vibration will occur in any window.

[0042] Second embodiment:

[0043] like Figure 5 , Figure 7As shown, when L1 = L - 0.7L0, the length direction motion degree of freedom of the steel ball 4 in the limiting window 301 is a = 0.3L0. After the steel ball 4 in the limiting window 301 moves and abuts against the inner wall of the ball cage 3, the steel ball 4 in the limiting window 301 and the ball cage 3 move synchronously. The length direction motion degree of freedom between the steel ball 4 in the non-limiting window 302 and the inner wall of the non-limiting window 302 is 0.7L0. In this embodiment, since there is a length direction motion degree of freedom of 0.3L0 between the length of the limiting window 301 and the steel ball 4, when the constant velocity universal joint rotates, the steel ball 4 in the limiting window 301 first moves to abut against the inner wall of the limiting window 301, and then the steel ball 4 in the limiting window 301 and the ball cage 3 move synchronously. The length direction motion degree of freedom of 0.7L0 between the steel ball 4 in the non-limiting window 302 and the inner wall of the non-limiting window 302 always exists, and no knocking vibration will occur. Therefore, in this embodiment, only the steel ball 4 in the limiting window 301 will knock and vibrate with the limiting window 301, while the steel ball 4 in the non-limiting window 302 will not knock and vibrate with the non-limiting window 302, which greatly reduces the abnormal noise of the constant velocity universal joint.

[0044] Third embodiment:

[0045] like Figure 8 As shown, the width of the limiting window 301 is smaller than the diameter of the steel ball 4. A limiting groove 303 is formed along the width extension direction of the limiting window 301. The sum of the groove depth and the width of the limiting window 301 matches the diameter of the steel ball 4. The steel ball 4 is engaged in the limiting groove 303, and the steel ball 4 is completely in contact with the inner wall of the limiting groove 303. The steel ball 4 in the limiting window 301 and the ball cage 3 rotate synchronously. The length direction motion degree of freedom between the steel ball 4 in the non-limiting window 302 and the inner wall of the non-limiting window 302 is L0. In this embodiment, the length of the limiting window 301 is the same as the length of the non-limiting window 302, i.e., L1=L. The steel ball 4 is engaged in the limiting groove 303 and loses its circumferential degree of freedom; therefore, in this embodiment, the length direction motion degree of freedom a=0 for the steel ball 4. The steel ball 4 in the limiting window 301 rotates synchronously with the ball cage 3. The steel ball 4 in the non-limiting window 302 and the length direction of the inner wall of the non-limiting window 302 always have the same degree of freedom of movement L0. No knocking vibration will occur in any window.

[0046] Fourth embodiment:

[0047] like Figure 9As shown, the width of the limiting window 301 is smaller than the diameter of the steel ball 4. A limiting groove 303 is formed in the limiting window 301 along the width extension direction. The sum of the groove depth of the limiting groove 303 and the width of the limiting window 301 matches the diameter of the steel ball 4. The steel ball 4 is stuck in the limiting groove 303 and can move along the length direction of the limiting window 301 in the limiting groove 303. The length direction motion degree of the steel ball 4 in the limiting groove 303 is a=0.3L0. After the steel ball 4 in the limiting window 301 moves and abuts against the inner wall of the limiting groove 303, the steel ball 4 in the limiting window 301 and the ball cage 3 move synchronously. The length direction motion degree of the steel ball 4 in the non-limiting window 302 and the inner wall of the non-limiting window 302 is 0.7L0. In this embodiment, the length of the limiting window 301 is the same as the length of the non-limiting window 302, i.e., L1=L. Since the length direction motion degree of freedom of the steel ball 4 in the limiting groove 303 is a=0.3L0, when the constant velocity universal joint rotates, the steel ball 4 first moves to abut against the inner wall of the limiting groove 303. Then, the steel ball 4 in the limiting window 301 and the ball cage 3 move synchronously. The steel ball 4 in the non-limiting window 302 always has a length direction motion degree of freedom of 0.7L0 with the inner wall of the non-limiting window 302, and no knocking vibration will occur. Therefore, in this embodiment, only the steel ball 4 in the limiting window 301 will knock against the inner wall of the limiting groove 303, and the steel ball 4 in the non-limiting window 302 will not knock against the non-limiting window 302, which greatly reduces the abnormal noise of the constant velocity universal joint.

[0048] Furthermore, in the above embodiments, the matching between the diameter of the steel ball 4 and the window size can include interference fit, transition fit, or clearance fit, etc., and the operator can make an appropriate selection according to the actual production situation.

[0049] To achieve the above or other objectives, the present invention also discloses a method for eliminating knocking noise in constant velocity universal joints. Addressing the problem of abnormal noise generated by constant velocity universal joints during operation, the steps are as follows:

[0050] A1: As Figure 5 As shown, any window or any pair of windows symmetrically distributed relative to the center of the ball cage 3 is selected as the limiting window 301, and the remaining windows are non-limiting windows 302; the length of the non-limiting window 302 is L, the diameter of the steel ball 4 is D, and the degree of freedom of the steel ball 4 in the length direction in the non-limiting window 302 is L0=LD.

[0051] The length of the limiting window 301 is L1; the length direction of the steel ball 4 in the limiting window 301 has a degree of freedom a; the width of the non-limiting window 302 is slightly larger than the diameter of the steel ball 4 so that the steel ball 4 can be placed into the non-limiting window 302.

[0052] A2: The length L1 of the limiting window 301, the width of the limiting window 301, and whether the limiting window 301 has a limiting groove 303 are designed so that when the steel ball 4 in the limiting window 301 abuts against the inner wall of the limiting window 301, the steel ball 4 in the non-limiting window 302 does not abut against the inner wall of the non-limiting window 302.

[0053] A3: Install the inner star wheel 1, outer star wheel 2, ball cage 3, and steel ball 4; when installing steel ball 4, install the steel ball 4 in the non-limiting window 302 first, and install the steel ball 4 in the limiting window 301 as the last or last two balls. Figure 10 As shown.

[0054] Preferably, in step A2, the width of the limiting window 301 is greater than the diameter of the steel ball 4, and the length of the limiting window 301 is D ≤ L1 ≤ L - 0.7L0. When the length of the limiting window 301 is L1 = D, it is the same as in the first embodiment, and can be referred to the first embodiment, which will not be repeated here. When the length of the limiting window 301 is L1 = L - 0.7L0, it is the same as in the second embodiment, and can be referred to the second embodiment, which will not be repeated here; when the length of the limiting window 301 is between D and 0.7L0, it is similar to the second embodiment, and can be referred to the second embodiment.

[0055] Preferably, in step A2, the width of the limiting window 301 is smaller than the diameter of the steel ball 4, and a limiting groove 303 is formed in the limiting window 301; the steel ball 4 is engaged in the limiting groove 303 and the steel ball 4 is completely in contact with the inner wall of the limiting groove 303, and the length direction motion degree of freedom of the steel ball 4 in the limiting groove 303 is a=0; or the steel ball 4 moves along the length direction of the limiting window 301 in the limiting groove 303, and the length direction motion degree of freedom of the steel ball 4 in the limiting groove 303 is 0<a≤0.3L0. When the outer peripheral surface of the steel ball 4 is completely in contact with the inner wall of the limiting groove 303, it is the same as the case in the third embodiment, and can be referred to the third embodiment, which will not be repeated here. When there is a length direction motion degree of freedom of 0-0.3L0 between the outer peripheral surface of the steel ball 4 and the inner wall of the limiting groove 303, it is the same as the case in the fourth embodiment, and can be referred to the fourth embodiment, which will not be repeated here.

[0056] Preferably, in step A3, the steel ball 4 in the limiting window 301 is installed last to avoid the ball cage 3 entering a synchronization state when installing the steel ball 4 in other windows, which would prevent the constant velocity universal joint from swinging to the assembly angle and thus prevent the steel ball 4 in other windows from being unable to be installed.

[0057] The constant velocity universal joint and the method for eliminating knocking noise in the constant velocity universal joint involved in this invention are provided with a limiting window 301. The degree of freedom of the steel ball 4 in the limiting window 301 is reduced. When the friction of the inner star wheel 1 and the outer star wheel 2 of the ball cage 3 pushes the steel ball 4 to contact one side of the window in the length direction, the steel ball 4 in the limiting window 301 first contacts the inner wall of one side of the limiting window 301 in the length direction. At this time, the steel ball 4 in the non-limiting window 302 will not contact the inner wall of the non-limiting window 302 in the length direction, thereby completely eliminating the knocking vibration of the steel ball 4 in the non-limiting window 302. Only the knocking vibration of the steel ball 4 in the limiting window 301 exists, which greatly reduces the abnormal noise in the constant velocity universal joint. In addition, when the length direction of the steel ball 4 in the limiting window 301 has a degree of freedom of a=0, the rotation of the ball cage 3 is completely synchronized with the steel ball 4 in the limiting window 301. The steel ball 4 in the limiting window 301 and the steel ball 4 in the non-limiting window 302 will not produce knocking vibration, thus fundamentally avoiding knocking noise in the constant velocity universal joint.

[0058] In the constant velocity universal joint involved in this invention, the movement position of the steel ball 4 in the constant velocity universal joint is mainly determined by the swing angle and the ball track trajectory. Through the characteristic design of the ball cage 3, the relative movement between the steel ball 4 and the ball cage 3 is changed to limit or synchronize them. Each steel ball 4 is in its own window of the ball cage 3 and does not strike one side of the window length direction.

[0059] Therefore, this invention effectively overcomes the various shortcomings of the prior art and has high industrial application value.

[0060] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A constant velocity universal joint, comprising an outer star wheel (2), an inner star wheel (1), a ball cage (3), and a plurality of steel balls (4), wherein the inner wall of the outer star wheel (2) is provided with a plurality of inner ball tracks equally spaced, the outer wall of the inner star wheel (1) is provided with a plurality of outer ball tracks equally spaced, and the ball cage (3) is provided with a plurality of windows equally spaced; the ball cage (3) is disposed between the inner star wheel (1) and the outer star wheel (2), and the inner ball tracks, windows, and outer ball tracks are aligned; the plurality of steel balls (4) are disposed between the inner ball tracks, windows, and outer ball tracks; characterized in that: Any window or any pair of windows symmetrically distributed around the center of the ball cage (3) is set as a limiting window (301), and the remaining windows are non-limiting windows (302); when the steel ball (4) in the constant velocity universal joint rotation limiting window (301) contacts the inner wall of the limiting window (301), the steel ball (4) in the non-limiting window (302) will not contact the inner wall of the non-limiting window (302); The length of the non-restricted window (302) is L, the diameter of the steel ball (4) is D, the width of the non-restricted window (302) matches the diameter of the steel ball (4), and the length direction motion degree of the steel ball (4) in the non-restricted window (302) is L0=LD; the length of the restricted window (301) is L1, and the length direction motion degree of the steel ball (4) in the restricted window (301) is a=L1-D; the value range of a is 0≤a≤0.3L0.

2. The constant velocity universal joint according to claim 1, characterized in that: When L1=D, the length direction motion degree of the steel ball (4) in the limiting window (301) is a=0; the steel ball (4) in the limiting window (301) and the ball cage (3) rotate synchronously, and the length direction motion degree of the steel ball (4) in the non-limiting window (302) and the inner wall of the non-limiting window (302) is L0.

3. The constant velocity universal joint according to claim 1, characterized in that: When L1 = L - 0.7L0, the length direction motion degree of the steel ball (4) in the limiting window (301) is a = 0.3L0. After the steel ball (4) in the limiting window (301) moves and comes into contact with the inner wall of the ball cage (3), the steel ball (4) in the limiting window (301) and the ball cage (3) move synchronously. The length direction motion degree of the steel ball (4) in the non-limiting window (302) and the inner wall of the non-limiting window (302) is 0.7L0.

4. The constant velocity universal joint according to claim 1, characterized in that: The width of the limiting window (301) is smaller than the diameter of the steel ball (4). The limiting window (301) has a limiting groove (303) along the width extension direction. The sum of the groove depth of the limiting groove (303) and the width of the limiting window (301) matches the diameter of the steel ball (4). The steel ball (4) is stuck in the limiting groove (303) and the steel ball (4) is completely in contact with the inner wall of the limiting groove (303). The steel ball (4) in the limiting window (301) and the ball cage (3) rotate synchronously. The length direction motion degree of the steel ball (4) in the non-limiting window (302) and the inner wall of the non-limiting window (302) is L0.

5. The constant velocity universal joint according to claim 1, characterized in that: The width of the limiting window (301) is smaller than the diameter of the steel ball (4). The limiting window (301) has a limiting groove (303) extending along its width. The sum of the groove depth of the limiting groove (303) and the width of the limiting window (301) matches the diameter of the steel ball (4). The steel ball (4) is engaged in the limiting groove (303) and can move along the length of the limiting window (301) within the limiting groove (303). The steel ball (4) has a length direction motion degree of freedom a = 0.3L0 in the limiting groove (303); after the steel ball (4) in the limiting window (301) moves and abuts against the inner wall of the limiting groove (303), the steel ball (4) in the limiting window (301) and the ball cage (3) move synchronously, and the length direction motion degree of freedom between the steel ball (4) in the non-limiting window (302) and the inner wall of the non-limiting window (302) is 0.7L0.

6. A method for eliminating knocking noise in a constant velocity universal joint, addressing the problem of abnormal noise generated during operation in the constant velocity universal joint as described in any one of claims 1-5, characterized in that: The steps are as follows: S1: Select any window or any pair of windows that are symmetrically distributed around the center of the ball cage (3) as the limiting window (301), and the remaining windows are non-limiting windows (302); the length of the non-limiting window (302) is L, the diameter of the steel ball (4) is D, and the length direction motion degree of the steel ball (4) in the non-limiting window (302) is L0=LD; the length of the limiting window (301) is L1; the length direction motion degree of the steel ball (4) in the limiting window (301) is a; S2: The length L1 of the limiting window (301), the width of the limiting window (301), and whether the limiting window (301) has a limiting groove (303) are designed so that when the steel ball (4) in the limiting window (301) abuts against the inner wall of the limiting window (301), the steel ball (4) in the non-limiting window (302) does not abut against the inner wall of the non-limiting window (302); S3: Then install the inner star wheel (1), outer star wheel (2), ball cage (3), and steel ball (4); when installing the steel ball (4), the steel ball (4) in the non-limiting window (302) is installed first, and the steel ball (4) in the limiting window (301) is installed as the last one or the last two.

7. The method for eliminating knocking noise from constant velocity universal joints according to claim 6, characterized in that: In step S2, the width of the limiting window (301) is greater than the diameter of the steel ball (4), and the length of the limiting window (301) is D≤L1≤L-0.7L0.

8. The method for eliminating knocking noise from constant velocity universal joints according to claim 6, characterized in that: In step S2, the width of the limiting window (301) is smaller than the diameter of the steel ball (4), and a limiting groove (303) is opened in the limiting window (301); the steel ball (4) is stuck in the limiting groove (303) and the steel ball (4) is completely attached to the inner wall of the limiting groove (303), and the degree of freedom of the steel ball (4) in the longitudinal direction in the limiting groove (303) is a=0; or the steel ball (4) moves in the limiting groove (303) along the longitudinal direction of the limiting window (301), and the degree of freedom of the steel ball (4) in the longitudinal direction in the limiting groove (303) is 0<a≤0.3L0.

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