A transmission shaft

Abstract

The present invention relates to the field of vehicle transmission technology, and in particular, to a transmission shaft. A first shaft assembly; a second shaft assembly, one end of the second shaft assembly is detachably connected to one end of the first shaft assembly; a buffer assembly, the buffer assembly includes a buffer unit, a rotating unit, and a supporting unit; the inner circumferential wall of the rotating unit abuts against the outer circumferential wall of the second shaft assembly near one end of the first shaft assembly; the buffer unit is arranged in a ring shape; the inner circumferential wall of the buffer unit abuts against the outer circumferential wall of the rotating unit, and the outer circumferential wall of the buffer unit abuts against the inner circumferential wall of the supporting unit; the axis of the rotating unit coincides with the axis of the supporting unit; S1<S2, S1 is the cross-sectional area of ​​the hollow cavity of the buffer unit located above the second shaft assembly before installation, and S2 is the cross-sectional area of ​​the hollow cavity of the buffer unit located below the second shaft assembly after installation. In this way, the problem of downward deflection caused by the deadweight of the transmission shaft is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle transmission, and in particular to a transmission shaft. Background Art

[0002] As an important component of mechanical transmission, the transmission shaft is widely used in vehicles. As a bridge connecting the engine and the drive device, the performance of the transmission shaft directly affects the operating efficiency and stability of the entire vehicle. The transmission shaft is mainly composed of a first shaft assembly, a second shaft assembly and a buffer assembly. The first shaft assembly is detachably connected to the second shaft assembly, the buffer assembly is annular, and the inner circumferential wall of the buffer assembly abuts against the outer circumferential wall of the second shaft assembly near one end of the first shaft assembly.

[0003] However, in actual use, since the first shaft assembly and the second shaft assembly of the drive shaft are connected by a universal joint, the drive shaft may deflect when affected by its own weight, thereby reducing the transmission efficiency of the drive shaft and increasing the vibration, seriously affecting the driving safety of the vehicle. Summary of the invention

[0004] In order to solve the problem of deflection caused by the deadweight of the transmission shaft, the present invention provides a transmission shaft, the transmission shaft comprising:

[0005] A first shaft assembly;

[0006] a second shaft assembly, one end of which is detachably connected to one end of the first shaft assembly;

[0007] A buffer assembly, the buffer assembly comprising a buffer unit, a rotating unit, and a supporting unit; the inner circumferential wall of the rotating unit abuts against the outer circumferential wall of the second shaft assembly near one end of the first shaft assembly; the buffer unit is arranged in a ring shape; the inner circumferential wall of the buffer unit abuts against the outer circumferential wall of the rotating unit, and the outer circumferential wall of the buffer unit abuts against the inner circumferential wall of the supporting unit; the axis of the rotating unit coincides with the axis of the supporting unit; S1<S2, S1 is the cross-sectional area of ​​the hollow cavity of the buffer unit located above the second shaft assembly before installation, and S2 is the cross-sectional area of ​​the hollow cavity of the buffer unit located below the second shaft assembly after installation.

[0008] In some embodiments, the rotating unit includes a bearing; the inner peripheral wall of the bearing abuts against the outer peripheral wall of the second shaft assembly close to one end of the first shaft assembly;

[0009] The buffer unit includes two inner ring skeletons, two outer ring skeletons, and two buffer modules; the inner circumferential wall of the inner ring skeleton abuts against the outer circumferential wall of the rotating unit; the two inner ring skeletons are symmetrically arranged along the set plane; the inner ring skeleton includes a first mounting frame, a first connecting frame, and a second mounting frame; the second mounting frame abuts against the outer circumferential wall of the bearing; one end of the first connecting frame is fixedly connected to one end of the second mounting frame away from the set plane, and the other end extends toward the direction close to the second shaft assembly; the first mounting frame is fixedly connected to one end of the first connecting frame close to the second shaft assembly, and the other end extends toward the direction away from the bearing; the first mounting frame and the second shaft assembly are spaced apart; wherein, the set plane includes a symmetry plane of the bearing along the axial direction.

[0010] In some embodiments, L1:L2=1~1.2; L1 is the minimum distance between the outer peripheral wall of the outer ring of the bearing and the outer peripheral wall of the inner ring of the bearing; L2 is the length of the first connecting frame.

[0011] In some embodiments, the buffer module includes a first mounting body, a first connecting body, a second connecting body, and a second mounting body; the first mounting body is fixedly connected to the outer peripheral wall of the inner ring skeleton; one end of the first connecting body is fixedly connected to the first mounting body, and the other end extends away from the inner ring skeleton; one end of the second connecting body is fixedly connected to one end of the first connecting body away from the first mounting body, and the other end extends toward the set plane; the second mounting body is fixedly connected to the other end of the second connecting body; the second mounting body is fixedly connected to the outer ring skeleton; the outer ring skeleton is detachably connected to the support unit; the two outer ring skeletons are symmetrically arranged along the set plane.

[0012] In some embodiments, the inner peripheral wall of the connection between the first connecting body and the second connecting body is arc-shaped.

[0013] In some embodiments, the radius of the inner wall at the connection between the first connector and the second connector is 35 mm to 45 mm.

[0014] In some embodiments, L3:L4=1.1~1.6; wherein, L3 is the distance from the outer peripheral side of the inner ring skeleton to the inner peripheral side of the outer ring skeleton after installation; L4 is the distance from the connection between the first mounting body and the first connecting body to the connection between the second mounting body and the second connecting body after installation.

[0015] In some embodiments, the rotating unit further comprises a limit seat; the inner circumferential wall of the limit seat abuts against the outer circumferential wall of one end of the second shaft assembly close to the first shaft assembly; the end of the limit seat away from the first shaft assembly abuts against the bearing.

[0016] In some embodiments, the buffer assembly also includes a sealing unit; the sealing unit includes two sealing modules; the sealing module includes a sealing body, a first sealing lip, a second sealing lip, and a third sealing lip; the sealing body is detachably connected to the first mounting frame; one end of the first sealing lip is fixedly connected to the side of the sealing body away from the bearing, and the other end extends toward the second shaft assembly and is inclined away from the bearing; the second sealing lip is arranged on the side of the first sealing lip close to the bearing; one end of the second sealing lip is fixedly connected to the sealing body, and the other end extends toward the second shaft assembly and is inclined away from the bearing; the third sealing lip is arranged on the side of the second sealing lip close to the bearing; one end of the third sealing lip is fixedly connected to the sealing body, and the other end extends toward the second shaft assembly and is inclined toward the bearing; the first sealing lip, the second sealing lip, and the third sealing lip close to the limit seat are respectively abutted against the outer peripheral wall of the limit seat at one end away from the first mounting frame; the first sealing lip, the second sealing lip, and the third sealing lip away from the limit seat are respectively abutted against the outer peripheral wall of the second shaft assembly at one end away from the first mounting frame.

[0017] In some embodiments, the sealing unit includes two dust covers; one end of one dust cover is detachably connected to the first mounting frame, and the other end extends toward the direction close to the bearing and is inclined toward the direction away from the second shaft assembly; one end of the other dust cover is detachably connected to the second shaft assembly, and the other end extends toward the direction close to the bearing and is inclined toward the direction away from the second shaft assembly; the dust covers are spaced apart from the buffer unit.

[0018] In order to solve the problem of deflection caused by the deadweight of the transmission shaft, the present invention has the following advantages:

[0019] The first shaft assembly and the second shaft assembly are detachably connected, the buffer unit is arranged in a ring shape, and the inner circumferential wall of the buffer unit abuts against the outer circumferential wall of the rotating unit, and the inner circumferential wall of the rotating unit abuts against the outer circumferential wall of the second shaft assembly close to one end of the first shaft assembly, so that the buffer unit can play a certain buffering role for the rotating unit, the second shaft assembly and the first shaft assembly. At the same time, the cross-sectional area of ​​the hollow cavity of the buffer unit above the second shaft assembly before installation is smaller than the cross-sectional area of ​​the hollow cavity of the buffer unit below the second shaft assembly after installation, so that the deformation of the buffer unit after assembly can offset the downward deflection of the transmission shaft and increase the stability of the transmission shaft. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of a transmission shaft of a first embodiment is shown;

[0021] Figure 2 A partial schematic diagram of a transmission shaft of a first embodiment is shown;

[0022] Figure 3 A partial schematic diagram of a transmission shaft of a second embodiment is shown;

[0023] Figure 4 A schematic diagram of a transmission shaft of a second embodiment is shown.

[0024] Figure markings: 01 buffer assembly; 11 buffer unit; 111 inner ring skeleton; 1111 first mounting frame; 1112 first connecting frame; 1113 second mounting frame; 112 outer ring skeleton; 113 buffer module; 1131 first mounting body; 1132 first connecting body; 1133 second connecting body; 1134 second mounting body; 12 sealing unit; 121 sealing module; 1211 sealing body; 1212 first sealing lip; 1213 second sealing lip; 1214 third sealing lip; 122 dust cover; 13 rotating unit; 131 bearing; 132 limiting seat; 14 supporting unit; 02 first shaft assembly; 21 first universal joint; 22 first shaft tube; 23 second universal joint; 03 second shaft assembly; 31 connecting shaft; 32 second shaft tube; 33 third universal joint; 34 resistor. DETAILED DESCRIPTION

[0025] The present disclosure will now be discussed with reference to several exemplary embodiments. It should be understood that these embodiments are discussed only to enable those skilled in the art to better understand and thus implement the present disclosure, rather than implying any limitation on the scope of the present disclosure.

[0026] As used herein, the term "including" and its variants are to be interpreted as open-ended terms meaning "including but not limited to". The term "based on" is to be interpreted as "based at least in part on". The terms "one embodiment" and "an embodiment" are to be interpreted as "at least one embodiment". The term "another embodiment" is to be interpreted as "at least one other embodiment". The orientation or position relationship indicated by the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "vertical", "horizontal", "lateral", "longitudinal" and the like is based on the orientation or position relationship shown in the accompanying drawings. These terms are mainly for better describing the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation. In addition, in addition to being used to indicate an orientation or position relationship, some of the above terms may also be used to indicate other meanings, such as the term "upper" may also be used to indicate a certain dependency or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to the specific circumstances. In addition, the terms "install", "set", "provided with", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure. It can be a mechanical connection or an electrical connection. It can be directly connected, or indirectly connected through an intermediate medium, or it can be an internal connection between two devices, elements or components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances. In addition, the terms "first", "second", etc. are mainly used to distinguish different devices, elements or components (the specific types and structures may be the same or different), and are not used to indicate or imply the relative importance and quantity of the indicated devices, elements or components. Unless otherwise specified, "multiple" means two or more.

[0027] The transmission shaft is a key component used to connect the engine and the drive device on the vehicle, and is mainly composed of the first shaft assembly 02, the second shaft assembly 03 and the buffer assembly 01. During the use of the transmission shaft, the first shaft assembly 02 and the second shaft assembly 03 are detachably connected, so that the transmission shaft will bend downward under the influence of its own weight, which will cause additional vibration during the transmission process of the transmission shaft, affecting the service life of the transmission shaft, and at the same time reducing the transmission efficiency of the transmission shaft, which has a great impact on the safety and driving efficiency of the vehicle. Figure 1 As shown, this embodiment provides a transmission shaft, which may include a first shaft component 02, a second shaft component 03 and a buffer component 01. Figure 4As shown, one end of the second shaft assembly 03 can be detachably connected to one end of the first shaft assembly 02, so that the power transmission of the transmission shaft is realized through the first shaft assembly 02 and the second shaft assembly 03. The buffer assembly 01 may include a buffer unit 11, a rotating unit 13 and a supporting unit 14. The inner peripheral wall of the rotating unit 13 may abut against the outer peripheral wall of one end of the second shaft assembly 03 close to the first shaft assembly 02, and the rotating unit 13 may reduce the friction between the buffer unit 11 and the second shaft assembly 03, so as to support the rotation of the transmission shaft. At the same time, the second shaft assembly 03 may transmit vibration to the buffer unit 11 through the rotating unit 13. The buffer unit 11 may be arranged in an annular shape, so that the vibration on the second shaft assembly 03 can be uniformly transmitted to the buffer unit 11. The inner peripheral wall of the buffer unit 11 may abut against the outer peripheral wall of the rotating unit 13, so that the buffer unit 11 can play a certain buffering role on the vibration of the rotating unit 13, the first shaft assembly 02 and the second shaft assembly 03. The outer peripheral wall of the buffer unit 11 can abut against the inner peripheral wall of the support unit 14, so that the position of the buffer unit 11 can be fixed by the support unit 14, and the support unit 14 can be connected to the vehicle, and the relative position of the buffer unit 11 and the vehicle can be fixed by the support unit 14. The axis of the rotating unit 13 can coincide with the axis of the support unit 14, so that the support unit 14 can be evenly stressed, and at the same time, the uneven weight distribution of the buffer unit 11 and the support unit 14 is prevented from affecting the transmission efficiency of the transmission shaft. The cross-sectional area of ​​the hollow cavity of the buffer unit 11 above the second shaft assembly 03 before installation can be smaller than the cross-sectional area of ​​the hollow cavity of the buffer unit 11 below the second shaft assembly 03 after installation. After installation, the transmission shaft will bend downward due to the deadweight of the transmission shaft. In this way, the deformation of the buffer unit 11 after assembly can offset the deflection of the transmission shaft, and the central axis of the first shaft and the central axis of the second shaft are made to be collinear as much as possible, thereby increasing the stability of the transmission shaft. In other embodiments, the first shaft assembly 02 may include a first shaft tube 22 , a first universal joint 21 , and a second universal joint 23 . The second shaft assembly 03 may include a connecting shaft 31 , a second shaft tube 32 , a third universal joint 33 , and a resistor 34 .

[0028] In this embodiment, the rotating unit 13 may include a bearing 131, which may support the first shaft assembly 02 and the second shaft assembly 03 and may also support the rotation of the first shaft assembly 02 and the second shaft assembly 03. The inner circumferential wall of the bearing 131 may abut against the outer circumferential wall of the second shaft assembly 03 near one end of the first shaft assembly 02, so that the second shaft assembly 03 may transmit vibration to the inner circumferential wall of the bearing 131.

[0029] The buffer unit 11 may include two inner ring skeletons 111, two outer ring skeletons 112, and two buffer modules 113. The inner peripheral wall of the inner ring skeleton 111 may abut against the outer peripheral wall of the rotating unit 13, and the two inner ring skeletons 111 may be symmetrically arranged along the set plane to fix the relative positions of the inner ring skeleton 111 and the rotating unit 13. The inner ring skeleton 111 may include a first mounting frame 1111, a first connecting frame 1112, and a second mounting frame 1113. The second mounting frame 1113 may abut against the outer peripheral wall of the bearing 131. One end of the first connecting frame 1112 may be fixedly connected to one end of the second mounting frame 1113 away from the set plane, and the other end extends toward the direction close to the second shaft assembly 03, so that the first connecting frame 1112 can abut against the end surface portion of the bearing 131 to prevent foreign matter from entering the bearing 131 assembly and affecting the performance of the bearing 131. The first mounting frame 1111 can be fixedly connected to one end of the first connecting frame 1112 close to the second shaft assembly 03, and the other end extends in a direction away from the bearing 131. The first mounting frame 1111 can be spaced apart from the second shaft assembly 03. In other embodiments, a rubber sleeve can be installed on the inner ring skeleton 111 to increase the friction between the inner ring skeleton 111 and the bearing 131 to prevent the inner ring skeleton 111 and the bearing 131 from sliding relative to each other. The setting plane can include a symmetrical plane of the bearing 131 along the axial direction.

[0030] In this embodiment, if Figure 2 As shown, L1:L2=1~1.2. L1 is the distance between the outer peripheral wall of the outer ring of the bearing 131 and the inner peripheral wall of the inner ring of the bearing 131. L2 is the length of the first connecting frame 1112. Thus, the first connecting frame 1112 can cover more bearings 131, so that the first connecting frame 1112 has a better dustproof effect on the bearing 131, and at the same time, the sealing module 121 can be installed between the first mounting frame 1111 and the limiting seat 132, and the contact area between the seal and the skeleton is large and fixed stably.

[0031] In this embodiment, the buffer module 113 may include a first mounting body 1131, a first connecting body 1132, a second connecting body 1133, and a second mounting body 1134. The first mounting body 1131 may be fixedly connected to the outer peripheral wall of the inner ring skeleton 111 to fix the relative position of the first mounting body 1131 and the inner ring skeleton 111. One end of the first connecting body 1132 may be fixedly connected to the first mounting body 1131, and the other end may extend in a direction away from the inner ring skeleton 111. One end of the second connecting body 1133 is fixedly connected to one end of the first connecting body 1132 away from the first mounting body 1131, and the other end extends toward a set plane. The second mounting body 1134 is fixedly connected to the other end of the second connecting body 1133. The second mounting body 1134 is fixedly connected to the outer ring skeleton 112, so that when the buffer module 113 is subjected to a large pressure or vibration, the buffer module 113 can be deformed to make the buffer module 113 play a certain buffering role on the vibration of the transmission shaft. The outer ring skeleton 112 is detachably connected to the support unit 14. The two outer ring skeletons 112 can be symmetrically arranged along a set plane to prevent the uneven force on the outer ring skeleton 112 from affecting the performance of the transmission shaft.

[0032] In this embodiment, the inner peripheral wall of the connection between the first connecting body 1132 and the second connecting body 1133 may be arc-shaped, so that the cross-sectional area of ​​the hollow cavity of the buffer module 113 is larger, so that the buffer module 113 has a better buffering effect. At the same time, the arc-shaped design also allows the buffer module 113 to better adapt to impacts at different angles, thereby enhancing the adaptability of the buffer module 113. At the same time, the arc-shaped design saves material at the connection between the first connecting body 1132 and the second connecting body 1133, thereby making the buffer module 113 lighter in weight and avoiding the material of the first mounting body 1131 and the second mounting body 1134 in the buffer module 113 from falling, thereby interfering with other components.

[0033] In this embodiment, the radius of the inner circumferential wall at the connection between the first connector 1132 and the second connector 1133 may include 35 mm to 45 mm. This makes the cross-sectional area of ​​the hollow cavity of the buffer module 113 moderate, and the buffer space can be expanded within a limited space. If the radius is too large, the length of the buffer module 113 along the axial direction of the transmission shaft will be too large, so that the side of the buffer module 113 away from the first mounting body 1131 is too close to other components on the vehicle (such as the exhaust pipe), making the buffer module 113 prone to overheating. If the radius is too small, the buffer module 113 will have a poor buffering effect and be prone to bending fatigue, thereby affecting the service life of the buffer module 113.

[0034] In this embodiment, if Figure 3As shown, L3:L4=1.1~1.6. Among them, L3 is the distance from the outer circumference of the inner ring skeleton 111 to the inner circumference of the outer ring skeleton 112 after installation. L4 is the distance between the connection between the first mounting body 1131 and the first connecting body 1132 and the connection between the second mounting body 1134 and the second connecting body 1133 after installation. As a result, a certain space can be reserved between the buffer component 01 and the transmission shaft, so that the buffer module 113 can extend in the direction close to the second shaft component 03, thereby increasing the buffer space of the buffer component 01.

[0035] In this embodiment, the rotating unit 13 may further include a stopper 132. The inner peripheral wall of the stopper 132 may abut against the outer peripheral wall of the second shaft assembly 03 at one end close to the first shaft assembly 02. The end of the stopper 132 away from the first shaft assembly 02 may abut against the bearing 131. The stopper 132 cooperates with the second shaft assembly 03 to fix the relative position of the bearing 131 assembly, thereby preventing the bearing 131 assembly and the second shaft assembly 03 from sliding relative to each other.

[0036] In this embodiment, the buffer assembly 01 may further include a sealing unit 12. The sealing unit 12 may include two sealing modules 121. The sealing module 121 may include a sealing body 1211, a first sealing lip 1212, a second sealing lip 1213, and a third sealing lip 1214. The sealing body 1211 is detachably connected to the first mounting frame 1111. One end of the first sealing lip 1212 is fixedly connected to a side of the sealing body 1211 away from the bearing 131, and the other end extends toward the second shaft assembly 03 and tilts away from the bearing 131. The second sealing lip 1213 is arranged on a side of the first sealing lip 1212 close to the bearing 131. One end of the second sealing lip 1213 is fixedly connected to the sealing body 1211, and the other end extends toward the second shaft assembly 03 and tilts away from the bearing 131. The cavity between the first sealing lip 1212 and the second sealing lip 1213 can temporarily store dust when dust enters the bearing 131 from the first sealing lip 1212, thereby preventing dust from entering the bearing 131. The third sealing lip 1214 can be arranged on the side of the second sealing lip 1213 close to the bearing 131. One end of the third sealing lip 1214 is fixedly connected to the sealing body 1211, and the other end extends toward the second shaft assembly 03 and tilts toward the bearing 131 at the same time. The cavity between the third sealing lip 1214 and the sealing body 1211 can temporarily store grease to prevent the grease lubricated by the bearing 131 from overflowing, thereby affecting the performance of the bearing 131. The first sealing lip 1212, the second sealing lip 1213, and the third sealing lip 1214 close to the limiting seat 132, the end away from the first mounting frame 1111, respectively abut against the outer peripheral wall of the limiting seat 132, and the first sealing lip 1212, the second sealing lip 1213, and the third sealing lip 1214 away from the limiting seat 132, the end away from the first mounting frame 1111, respectively abut against the outer peripheral wall of the second shaft assembly 03, thereby playing a certain buffering role on the buffer assembly 01.

[0037] In this embodiment, the sealing unit 12 may include two dust covers 122. One end of one dust cover 122 is detachably connected to the first mounting frame 1111, and the other end extends in a direction close to the bearing 131 and tilts in a direction away from the second shaft assembly 03, thereby preventing dust from entering the bearing 131 and affecting the performance of the bearing 131. One end of the other dust cover 122 is detachably connected to the second shaft assembly 03, and the other end extends in a direction close to the bearing 131 and tilts in a direction away from the second shaft assembly 03, further preventing dust from entering the bearing 131 and affecting the performance of the bearing 131. The dust cover 122 and the buffer unit 11 may be spaced apart.

[0038] Those skilled in the art will appreciate that the above-mentioned embodiments are specific examples for implementing the present disclosure, and in actual applications, various changes may be made thereto in form and detail without departing from the scope of the present disclosure.

Claims

1. A transmission shaft, characterized in that: The transmission shaft comprises: A first shaft assembly; a second shaft assembly, one end of which is detachably connected to one end of the first shaft assembly; A buffer assembly, the buffer assembly comprising a buffer unit, a rotating unit, and a supporting unit; the inner circumferential wall of the rotating unit abuts against the outer circumferential wall of the second shaft assembly near one end of the first shaft assembly; the buffer unit is arranged in a ring shape; the inner circumferential wall of the buffer unit abuts against the outer circumferential wall of the rotating unit, and the outer circumferential wall of the buffer unit abuts against the inner circumferential wall of the supporting unit; the axis of the rotating unit coincides with the axis of the supporting unit; S1<S2, S1 is the cross-sectional area of ​​the hollow cavity of the buffer unit located above the second shaft assembly before installation, and S2 is the cross-sectional area of ​​the hollow cavity of the buffer unit located below the second shaft assembly after installation; The rotating unit comprises a bearing; the inner peripheral wall of the bearing abuts against the outer peripheral wall of the second shaft assembly close to one end of the first shaft assembly; The buffer unit includes two inner ring skeletons, two outer ring skeletons, and two buffer modules; the inner circumferential wall of the inner ring skeleton abuts against the outer circumferential wall of the rotating unit; the two inner ring skeletons are symmetrically arranged along the set plane; the inner ring skeleton includes a first mounting frame, a first connecting frame, and a second mounting frame; the second mounting frame abuts against the outer circumferential wall of the bearing; one end of the first connecting frame is fixedly connected to one end of the second mounting frame away from the set plane, and the other end extends toward the direction close to the second shaft assembly; the first mounting frame is fixedly connected to one end of the first connecting frame close to the second shaft assembly, and the other end extends toward the direction away from the bearing; the first mounting frame and the second shaft assembly are spaced apart; wherein, the set plane includes a symmetry plane of the bearing along the axial direction.

2. A transmission shaft according to claim 1, characterized in that: L1: L2=1~1.2; L1 is the minimum distance between the outer peripheral wall of the outer ring of the bearing and the outer peripheral wall of the inner ring of the bearing; L2 is the length of the first connecting frame.

3. A transmission shaft according to claim 1, characterized in that: The buffer module includes a first mounting body, a first connecting body, a second connecting body, and a second mounting body; the first mounting body is fixedly connected to the outer peripheral wall of the inner ring skeleton; one end of the first connecting body is fixedly connected to the first mounting body, and the other end extends away from the inner ring skeleton; one end of the second connecting body is fixedly connected to one end of the first connecting body away from the first mounting body, and the other end extends toward the set plane; the second mounting body is fixedly connected to the other end of the second connecting body; the second mounting body is fixedly connected to the outer ring skeleton; the outer ring skeleton is detachably connected to the support unit; the two outer ring skeletons are symmetrically arranged along the set plane.

4. A transmission shaft according to claim 3, characterized in that: The inner peripheral wall of the connection between the first connecting body and the second connecting body is arc-shaped.

5. A transmission shaft according to claim 4, characterized in that: The radius of the inner circumferential wall at the connection between the first connecting body and the second connecting body is 35 mm to 45 mm.

6. A transmission shaft according to claim 3, characterized in that: L3: L4=1.1~1.6; wherein, L3 is the distance from the outer circumference of the inner ring skeleton to the inner circumference of the outer ring skeleton after installation; L4 is the distance from the connection between the first mounting body and the first connecting body to the connection between the second mounting body and the second connecting body after installation.

7. A transmission shaft according to claim 1, characterized in that: The rotating unit further comprises a limiting seat; the inner peripheral wall of the limiting seat abuts against the outer peripheral wall of one end of the second shaft assembly close to the first shaft assembly; and the end of the limiting seat away from the first shaft assembly abuts against the bearing.

8. A transmission shaft according to claim 7, characterized in that: The buffer assembly also includes a sealing unit; the sealing unit includes two sealing modules; the sealing module includes a sealing body, a first sealing lip, a second sealing lip, and a third sealing lip; the sealing body is detachably connected to the first mounting frame; one end of the first sealing lip is fixedly connected to the side of the sealing body away from the bearing, and the other end extends toward the second shaft assembly and is inclined away from the bearing; the second sealing lip is arranged on the side of the first sealing lip close to the bearing; one end of the second sealing lip is fixedly connected to the sealing body, and the other end extends toward the second shaft assembly and is inclined away from the bearing; the third sealing lip is arranged on the side of the second sealing lip close to the bearing; one end of the third sealing lip is fixedly connected to the sealing body, and the other end extends toward the second shaft assembly and is inclined toward the bearing; the first sealing lip, the second sealing lip, and the third sealing lip close to the limit seat are respectively abutted against the outer peripheral wall of the limit seat at one end away from the first mounting frame; the first sealing lip, the second sealing lip, and the third sealing lip away from the limit seat are respectively abutted against the outer peripheral wall of the second shaft assembly at one end away from the first mounting frame.

9. A transmission shaft according to claim 8, characterized in that: The sealing unit includes two dust covers; one end of one dust cover is detachably connected to the first mounting frame, and the other end extends toward the direction close to the bearing and is inclined toward the direction away from the second shaft assembly; one end of the other dust cover is detachably connected to the second shaft assembly, and the other end extends toward the direction close to the bearing and is inclined toward the direction away from the second shaft assembly; the dust covers are spaced apart from the buffer unit.

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