Coupling and method of transmission
By designing the radial clearance of the drive shaft and the arc-shaped external spline structure, the coupling enhances the eccentricity compensation capability, solves the problem of insufficient eccentricity compensation in the existing technology, achieves the alignment effect, extends the service life, and protects the driven equipment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-03-03
- Publication Date
- 2026-06-05
AI Technical Summary
Existing couplings have insufficient ability to compensate for eccentricity during use, resulting in large bearing vibrations and severe spline wear, which affects service life and working efficiency.
A coupling was designed to enhance eccentricity compensation by using the radial clearance of the transmission shaft and the arc-shaped external spline structure, and to prevent excessive movement by using a boss for axial limiting, and to provide over-rotation protection by setting a preset circumferential fracture tooth.
It achieves alignment of the coupling during operation, avoids spline wear, extends service life, improves working efficiency, and protects the driven device in case of over-rotation.
Smart Images
Figure CN122148670A_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the field of mechanical transmission technology, and specifically relates to a coupling and transmission method. Background Technology
[0002] Couplings are mainly used to connect multiple drive devices, enabling them to transmit torque to each other and thus achieve common rotation.
[0003] Existing couplings typically connect the main drive and driven devices at both ends via flanges and splines, or both ends are connected via splines. However, in actual use, these couplings have limited overall eccentricity compensation capabilities. Furthermore, due to factors such as machining and installation errors, rotor deformation, bearing misalignment, and height discrepancies between the main and driven devices, it is difficult to achieve proper alignment during operation. This easily leads to deviations in bearing oil film pressure from normal values, resulting in significant bearing vibration at both ends of the coupling, unstable shaft position, spline wear, and impacting the overall service life and operating efficiency of the coupling. Summary of the Invention
[0004] To address the aforementioned issues, this application provides a coupling and transmission method that enhances eccentricity compensation capabilities, prevents spline wear, ensures overall service life and working efficiency, and provides over-rotation protection.
[0005] One type of coupling includes: A first connecting part is disposed on the main drive device; A second connecting part is disposed on the drive device; A drive shaft is coaxially disposed between the first connecting portion and the second connecting portion; The first connecting end of the drive shaft is splinedly connected to the first connecting part, and the first connecting end of the drive shaft and the first connecting part are provided with a radial gap along the drive shaft; The second connecting end of the drive shaft is splinedly connected to the second connecting part, and the second connecting end of the drive shaft and the second connecting part are provided with a radial gap along the drive shaft.
[0006] Furthermore, the first connecting part is provided with a first spline hole, and the second connecting part is provided with a second spline hole; The first connecting end of the drive shaft is splined to the first spline hole, and the second connecting end of the drive shaft is splined to the second spline hole; Furthermore, the transmission shaft is movable within a preset axial distance along its axial direction.
[0007] Furthermore, external splines are provided on the outer periphery of both the first connecting end and the second connecting end of the transmission shaft; The outer wall of the external spline teeth is arc-shaped.
[0008] Furthermore, the distance between the outer wall of the middle part of the external spline and the center line of the external spline is greater than the distance between the outer wall of the end of the external spline and the center line of the external spline, so that the outer wall of the external spline is arc-shaped.
[0009] Furthermore, the difference between the distance between the outer wall of the middle part of the external spline and the center line of the external spline and the distance between the outer wall of the end of the external spline and the center line of the external spline is a preset radial distance; The preset radial distance ranges from 0.102 mm to 0.127 mm.
[0010] Furthermore, a boss is provided on the outer periphery of the middle part of the drive shaft; The boss is axially aligned with the end faces of the opening ends of the first spline hole and the second spline hole, respectively, on both sides along the axial direction of the drive shaft.
[0011] Furthermore, a first inner groove is provided on the end face of the opening end of the first spline hole, and a second inner groove is provided on the end face of the opening end of the second spline hole. The boss has an outer groove on the side near the first spline hole; The outer diameter of the bottom of the outer groove is adapted to the inner diameter of the bottom of the first inner groove, and the outer diameter of the bottom of the outer groove is larger than the inner diameter of the bottom of the second inner groove.
[0012] Furthermore, both the end face of the first connecting end of the drive shaft and the end face of the second connecting end of the drive shaft are provided with hollow grooves along the circumference of the drive shaft.
[0013] Furthermore, the width of one of the external splines along the circumference of the drive shaft is a preset circumferential distance; When the main drive device over-rotates, the external spline tooth with a width of a preset circumferential distance along the circumferential direction of the drive shaft breaks.
[0014] A transmission method based on the same concept, using the coupling as described above, includes the following steps: The first connecting end of the drive shaft is splinedly connected to the first connecting part provided on the main drive device, and the second connecting end of the drive shaft is splinedly connected to the second connecting part provided on the slave drive device. Start the main drive device, which drives the slave drive device to run together via the transmission shaft; The first connecting end of the drive shaft moves radially relative to the first connecting portion, and the second connecting end of the drive shaft moves radially relative to the second connecting portion.
[0015] Compared with the prior art, this application has the following advantages: The coupling of this application, through the radial clearance between the first connecting end and the first connecting portion of the drive shaft, allows the first connecting end of the drive shaft to move radially relative to the first connecting portion. Similarly, through the radial clearance between the second connecting end and the second connecting portion of the drive shaft, the second connecting end of the drive shaft can move radially relative to the second connecting portion. This enhances the coupling's eccentricity compensation capability, enabling the coupling to achieve alignment during operation, thereby preventing spline wear and ensuring the overall service life and working efficiency of the coupling. Simultaneously, the arc-shaped external splines on the first and second connecting ends of the drive shaft further improve the coupling's eccentricity compensation capability, allowing the coupling to achieve smooth alignment in both the horizontal and vertical directions, further ensuring the overall service life and working efficiency of the coupling. Furthermore, the bosses provided on the drive shaft can axially limit the drive shaft, preventing excessive axial movement and further avoiding spline wear. The external splines with a width of a preset circumferential distance can break when the main drive equipment over-rotates, thus preventing damage to the secondary drive equipment and achieving over-rotation protection.
[0016] The transmission method of the coupling in this application has the same beneficial effects as the coupling described above, since it uses the coupling described above. Therefore, it will not be repeated here.
[0017] Other features and advantages of this application will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the application. The objectives and other advantages of this application may be realized and obtained by means of the structures pointed out in the description, claims and drawings. Attached Figure Description
[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0019] Figure 1 A schematic diagram of a coupling according to an embodiment of this application is shown; Figure 2 A schematic diagram of a drive shaft according to an embodiment of this application is shown; Figure 3 One of the schematic diagrams of external spline teeth according to an embodiment of this application is shown; Figure 4 A second schematic diagram of external spline teeth according to an embodiment of this application is shown; Figure 5 for Figure 1 One of the magnified views of a section; Figure 6 for Figure 1 The second enlarged view of a section; Figure 7 A flowchart of a transmission method for a coupling according to an embodiment of this application is shown.
[0020] In the figure, 100 is the first connecting part; 110 is the first spline hole; 111 is the first inner groove; 200 is the second connecting part; 210 is the second spline hole; 211 is the second inner groove; 300 is the drive shaft; 310 is the external spline tooth; 320 is the boss; 321 is the external groove; and 330 is the hollow groove. Detailed Implementation
[0021] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0022] Reference Figure 1 This application provides a coupling including a first connecting portion 100, a second connecting portion 200, and a drive shaft 300. The first connecting portion 100 is disposed on a main drive device. The second connecting portion 200 is disposed on a driven device. The drive shaft 300 is coaxially disposed between the first connecting portion 100 and the second connecting portion 200. The first connecting end of the drive shaft 300 is splinedly connected to the first connecting portion 100, and the first connecting end of the drive shaft 300 and the first connecting portion 100 are separated by a radial clearance along the drive shaft 300. The second connecting end of the drive shaft 300 is splinedly connected to the second connecting portion 200, and the second connecting end of the drive shaft 300 and the second connecting portion 200 are separated by a radial clearance along the drive shaft 300.
[0023] Specifically, the first connecting part 100 is disposed on the driving end of the main driving device, and the second connecting part 200 is disposed on the driven end of the driven device. The transmission shaft 300 is coaxially disposed between the first connecting part 100 and the second connecting part 200, and the first connecting end of the transmission shaft 300 is splinedly connected to the first connecting part 100, and the second connecting end of the transmission shaft 300 is splinedly connected to the second connecting part 200, so that the main driving device can drive the driven device to rotate together through the transmission shaft 300, thereby realizing the transmission connection between the main driving device and the driven device. Because the first and second connecting ends of the drive shaft 300 are splined to the first connecting part 100 and the second connecting part 200 respectively, there is no need to consider the bolt length and wrench space of the original bolt connection method. This greatly reduces the axial and radial length of the coupling, making the overall structure of the coupling more compact, saving overall structural space, reducing the number of parts required, and reducing the overall types. This reduces the unbalanced torque when the main drive equipment and the driven equipment are connected, allowing the rotor system to have sufficient critical speed margin and avoiding resonance damage during transmission. The first connecting end of the drive shaft 300 and the first connecting part 100 are separated by a radial clearance along the drive shaft 300, and the second connecting end of the drive shaft 300 and the second connecting part 200 are separated by a radial clearance along the drive shaft 300. When the main drive device can drive the driven device to rotate together through the drive shaft 300, if there is eccentricity or installation error between the driving end of the main drive device and the driven end of the driven device, the first connecting end of the drive shaft 300 can be moved radially relative to the first connecting part 100, or the second connecting end of the drive shaft 300 can be moved radially relative to the second connecting part 200. This compensates for the angular and radial installation deviations caused by the misalignment of the axes of the driving end of the main drive device and the driven end of the driven device, thereby enhancing the eccentricity compensation capability of the coupling, enabling the coupling to achieve alignment during operation, thus avoiding spline wear and ensuring the overall service life and working efficiency of the coupling.
[0024] In some specific embodiments of this application, reference is made to Figure 1 The first connecting portion 100 is provided with a first spline hole 110, and the second connecting portion 200 is provided with a second spline hole 210. The first connecting end of the drive shaft 300 is splinedly connected to the first spline hole 110, and the second connecting end of the drive shaft 300 is splinedly connected to the second spline hole 210. The drive shaft 300 is movable within a preset axial distance along its axial direction.
[0025] Specifically, the first connecting part 100 is provided with a first spline hole 110, and internal spline teeth are provided inside the first spline hole 110. The first connecting end of the drive shaft 300 is coaxially inserted into the first spline hole 110 and splinedly connected to the first spline hole 110. The second connecting part 200 is provided with a second spline hole 210, and internal spline teeth are also provided inside the second spline hole 210. The second connecting end of the drive shaft 300 is coaxially inserted into the second spline hole 210 and splinedly connected to the second spline hole 210. The drive shaft 300 is movable within a preset axial distance along its axial direction. That is, the end face of the first connecting end of the drive shaft 300 is spaced apart from the bottom of the first spline hole 110, and the end face of the second connecting end of the drive shaft 300 is spaced apart from the bottom of the second spline hole 210. This meets the requirements for the axial movement of the drive shaft 300 when the main drive device and the driven device are connected, ensuring the operational stability of the drive shaft 300.
[0026] In some specific embodiments of this application, reference is made to Figure 2 External spline teeth 310 are provided on the outer periphery of both the first connecting end and the second connecting end of the drive shaft 300. The outer wall of the external spline teeth 310 is arc-shaped.
[0027] Specifically, external spline teeth 310 are provided on the outer periphery of both the first connecting end and the second connecting end of the drive shaft 300. The outer wall of the external spline teeth 310 is arc-shaped, thus enabling spline connection between the external spline teeth 310 and the internal spline teeth of the first spline hole 110 and the second spline hole 210, while simultaneously creating gaps between the arc-shaped outer wall of the external spline teeth 310 and the inner walls of the internal spline teeth of the first spline hole 110 and the second spline hole 210. This ensures that the first connecting end of the drive shaft 300 and the first connecting portion 100 are separated by a radial gap along the drive shaft 300, and the second connecting end of the drive shaft 300 and the second connecting portion 200 are separated by a radial gap along the drive shaft 300. The first connecting end of the drive shaft 300... The radial clearance along the transmission shaft 300 between the first connecting end and the first connecting portion 100 is the clearance between the arc-shaped outer wall of the external spline teeth 310 on the outer periphery of the first connecting end of the transmission shaft 300 and the inner wall of the internal spline teeth of the first spline hole 110. Similarly, the radial clearance along the transmission shaft 300 between the second connecting end of the transmission shaft 300 and the second connecting portion 200 is the clearance between the arc-shaped outer wall of the external spline teeth 310 on the outer periphery of the second connecting end of the transmission shaft 300 and the inner wall of the internal spline teeth of the second spline hole 210. This allows for radial movement of the first connecting end of the transmission shaft 300 relative to the first connecting portion 100 and radial movement of the second connecting end of the transmission shaft 300 relative to the second connecting portion 200. This further improves the eccentricity compensation capability of the coupling, enabling smooth alignment in both the horizontal and vertical directions, thereby further ensuring the overall service life and working efficiency of the coupling and guaranteeing the stability of the rotor system.
[0028] In some specific embodiments of this application, reference is made to Figure 3 and Figure 4 The distance between the outer wall of the middle part of the outer spline 310 and the center line of the outer spline 310 is greater than the distance between the outer wall of the end of the outer spline 310 and the center line of the outer spline 310, making the outer wall of the outer spline 310 arc-shaped.
[0029] Specifically, based on the centerline of the external spline 310, the spline is modified downwards from both sides of the tooth tip. The distance between the outer wall of the middle part of the external spline 310 and the centerline of the external spline 310 is greater than the distance between the outer wall of the end of the external spline 310 and the centerline of the external spline 310. This makes the outer wall of the tooth side of the external spline 310 form an arc shape, which can compensate for the angular and radial installation deviations caused by the misalignment of the shafts of the driving end of the main drive equipment and the driven end of the driven equipment. This enhances the eccentricity compensation capability of the coupling, avoids spline wear, and enables the coupling to be smoothly aligned in both the horizontal and vertical directions. This further ensures the overall service life and working efficiency of the coupling and guarantees the stability of the rotor system.
[0030] In some specific embodiments of this application, reference is made to Figure 3 and Figure 4 The difference between the distance between the outer wall of the middle part of the external spline 310 and the center line of the external spline 310 and the distance between the outer wall of the end of the external spline 310 and the center line of the external spline 310 is a preset radial distance H. The preset radial distance H ranges from 0.102 mm to 0.127 mm.
[0031] Specifically, the distance between the outer wall of the middle portion of the external spline tooth 310 and the center line of the external spline tooth 310 is greater than the distance between the outer wall of the end portion of the external spline tooth 310 and the center line of the external spline tooth 310. Furthermore, the difference between the distance between the outer wall of the middle portion of the external spline tooth 310 and the center line of the external spline tooth 310 and the distance between the outer wall of the end portion of the external spline tooth 310 and the center line of the external spline tooth 310, i.e., the depth of the arc-shaped outer wall of the external spline tooth 310, is a preset radial distance. The preset radial distance ranges from 0.102 mm to 0.127 mm. This allows for spline connection between the external spline tooth 310 and the inner spline teeth of the first spline hole 110 and the second spline hole 210, while maintaining a gap between the arc-shaped outer wall of the external spline tooth 310 and the inner walls of the inner spline teeth of the first spline hole 110 and the second spline hole 210, respectively, to ensure the stability of the rotor system.
[0032] In some specific embodiments of this application, reference is made to Figure 2 and Figure 5 A boss 320 is provided on the outer periphery of the middle part of the drive shaft 300. The two sides of the boss 320 along the axial direction of the drive shaft 300 are respectively axially coincident with the end face of the opening end of the first spline hole 110 and the end face of the opening end of the second spline hole 210.
[0033] Specifically, the boss 320 is circumferentially disposed on the outer periphery of the middle part of the drive shaft 300. The two sides of the boss 320 along the axial direction of the drive shaft 300 respectively coincide with the end faces of the opening ends of the first spline hole 110 and the second spline hole 210. When the drive shaft 300 moves along its axial direction toward the first connecting part 100, the side of the boss 320 near the first connecting part 100 abuts against the end face of the opening end of the first spline hole 110, thereby achieving [the desired effect] when the drive shaft 300 moves toward the first connecting part 100. The movement of the drive shaft 300 is stopped. At the same time, when the drive shaft 300 moves along the axial direction of the drive shaft 300 toward the direction close to the second connecting part 200, the boss 320 can abut against the end face of the opening end of the second spline hole 210 on the side close to the second connecting part 200, thereby stopping the movement of the drive shaft 300 toward the second connecting part 200. This can limit the axial displacement of the drive shaft 300 to within the sum of X1 and X2, avoiding excessive movement of the drive shaft 300 along the axial direction of the drive shaft 300, thereby reducing the risk of the drive shaft 300 rubbing against the ground.
[0034] In some specific embodiments of this application, reference is made to Figure 6 A first inner groove 111 is provided on the end face of the opening end of the first spline hole 110, and a second inner groove 211 is provided on the end face of the opening end of the second spline hole 210. An outer groove 321 is provided on the side of the boss 320 near the first spline hole 110. The outer diameter of the bottom of the outer groove 321 is adapted to the inner diameter of the bottom of the first inner groove 111, and the outer diameter of the bottom of the outer groove 321 is larger than the inner diameter of the bottom of the second inner groove 211.
[0035] Specifically, a first inner groove 111 is provided circumferentially around the drive shaft 300 on the inner side of the end face of the open end of the first spline hole 110, and a second inner groove 211 is provided circumferentially around the drive shaft 300 on the inner side of the end face of the open end of the second spline hole 210. An outer groove 321 is provided on the side of the boss 320 near the first spline hole 110. The outer diameter of the bottom of the outer groove 321 is adapted to the inner diameter of the bottom of the first inner groove 111. When the drive shaft 300 moves along the axial direction of the drive shaft 300 toward the direction close to the first connecting part 100, the groove wall of the outer groove 321 can fit and abut against the groove wall of the first inner groove 111. Meanwhile, the outer diameter R of the bottom of the outer groove 321 is greater than the inner diameter R2 of the bottom of the second inner groove 211, and the outer diameter R of the bottom of the outer groove 321 is less than or equal to the inner diameter R1 of the bottom of the first inner groove 111. Thus, through the mutual cooperation of the first inner groove 111, the second inner groove 211 and the outer groove 321, the installation direction of the drive shaft 300 can be restricted. If the first connecting end and the second connecting end of the drive shaft 300 are oriented incorrectly, the drive shaft 300 cannot be installed and connected to the first connecting part 100 and the second connecting part 200.
[0036] In some specific embodiments of this application, reference is made to Figure 2 Hollow grooves 330 are provided along the circumference of the drive shaft 300 on both the end face of the first connecting end and the end face of the second connecting end.
[0037] Specifically, both the end face of the first connecting end of the drive shaft 300 and the end face of the second connecting end of the drive shaft 300 are provided with circumferential slots 330 around the drive shaft 300. The slots 330 enable the drive shaft 300 to perform dynamic balancing, thereby improving the dynamic balancing accuracy of the rotating rotor and ensuring safe and reliable operation during rotation.
[0038] In some specific embodiments of this application, the width of one of the external splines 310 along the circumferential direction of the drive shaft 300 is a preset circumferential distance. When the main drive device over-rotates, the external spline 310 with a width of the preset circumferential distance along the circumferential direction of the drive shaft 300 breaks.
[0039] Specifically, one of the external spline teeth 310 has a circumferential width along the drive shaft 300 that is a preset circumferential distance. This makes the circumferential width of the external spline tooth 310 smaller than that of the other external spline teeth 310. This weakens the structural strength at the location of the external spline tooth 310 with a circumferential width of the preset circumferential distance. When the main drive device over-rotates, the external spline tooth 310 with a circumferential width of the preset circumferential distance will break, thereby stopping the driven device and preventing further damage to the driven device, thus achieving the over-rotation protection function. Reference Figure 7 This application also provides a transmission method for a coupling, using a coupling as described in any of the above specific embodiments, including the following steps: The first connecting end of the drive shaft 300 is splinedly connected to the first connecting portion 100 disposed on the main drive device, and the second connecting end of the drive shaft 300 is splinedly connected to the second connecting portion 200 disposed on the driven device. When the main drive device is started, the driven device is driven to run together via the drive shaft 300. The first connecting end of the drive shaft 300 moves radially relative to the first connecting portion 100, and the second connecting end of the drive shaft 300 moves radially relative to the second connecting portion 200.
[0040] Specifically, the radial clearance between the first connecting end of the drive shaft 300 and the first connecting portion 100 allows the first connecting end of the drive shaft 300 to move radially relative to the first connecting portion 100. Similarly, the radial clearance between the second connecting end of the drive shaft 300 and the second connecting portion 200 allows the second connecting end of the drive shaft 300 to move radially relative to the second connecting portion 200. This enhances the eccentricity compensation capability of the coupling, enabling it to achieve alignment during operation, thus preventing spline wear and ensuring the overall service life and efficiency of the coupling. Simultaneously, the arc-shaped external spline teeth 310 on the first and second connecting ends of the drive shaft 300 further improve the eccentricity compensation capability, allowing the coupling to achieve smooth alignment in both the horizontal and vertical directions, further ensuring the overall service life and efficiency of the coupling. Furthermore, the boss 320 on the drive shaft 300 provides axial restraint, preventing excessive axial movement of the drive shaft 300 and further avoiding spline wear. The external spline teeth 310, with a width of a preset circumferential distance, can break when the main drive device over-rotates, thereby preventing damage to the drive device and achieving over-rotation protection.
[0041] Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.
Claims
1. A coupling, characterized in that, include: A first connecting part (100) is disposed on the main drive device; The second connecting part (200) is provided on the drive device; A drive shaft (300) is coaxially disposed between the first connecting part (100) and the second connecting part (200); The first connecting end of the drive shaft (300) is splinedly connected to the first connecting part (100), and the first connecting end of the drive shaft (300) and the first connecting part (100) are provided with a radial gap along the drive shaft (300); The second connecting end of the drive shaft (300) is splinedly connected to the second connecting part (200), and the second connecting end of the drive shaft (300) and the second connecting part (200) are provided with a radial gap along the drive shaft (300).
2. The coupling according to claim 1, characterized in that, The first connecting part (100) is provided with a first spline hole (110), and the second connecting part (200) is provided with a second spline hole (210). The first connecting end of the drive shaft (300) is splined to the first spline hole (110), and the second connecting end of the drive shaft (300) is splined to the second spline hole (210). The transmission shaft (300) is moved within a preset axial distance along the axial direction of the transmission shaft (300).
3. The coupling according to claim 2, characterized in that, External splines (310) are provided on the outer periphery of the first connecting end of the drive shaft (300) and the outer periphery of the second connecting end of the drive shaft (300). The outer wall of the external spline tooth (310) is arc-shaped.
4. The coupling according to claim 3, characterized in that, The distance between the outer wall of the middle part of the external spline (310) and the center line of the external spline (310) is greater than the distance between the outer wall of the end of the external spline (310) and the center line of the external spline (310), so that the outer wall of the external spline (310) is arc-shaped.
5. The coupling according to claim 4, characterized in that, The difference between the distance between the outer wall of the middle part of the external spline (310) and the center line of the external spline (310) and the distance between the outer wall of the end of the external spline (310) and the center line of the external spline (310) is a preset radial distance. The preset radial distance ranges from 0.102 mm to 0.127 mm.
6. The coupling according to claim 2, characterized in that, A boss (320) is provided on the outer periphery of the middle part of the drive shaft (300). The boss (320) is axially aligned with the end face of the opening end of the first spline hole (110) and the end face of the opening end of the second spline hole (210) on both sides along the axial direction of the transmission shaft (300).
7. The coupling according to claim 6, characterized in that, A first inner groove (111) is provided on the end face of the opening end of the first spline hole (110), and a second inner groove (211) is provided on the end face of the opening end of the second spline hole (210). The boss (320) has an outer groove (321) on the side near the first spline hole (110). The outer diameter of the bottom of the outer groove (321) is adapted to the inner diameter of the bottom of the first inner groove (111), and the outer diameter of the bottom of the outer groove (321) is greater than the inner diameter of the bottom of the second inner groove (211).
8. The coupling according to claim 2, characterized in that, Hollow grooves (330) are provided on the end face of the first connecting end of the drive shaft (300) and the end face of the second connecting end of the drive shaft (300) along the circumference of the drive shaft (300).
9. The coupling according to claim 3, characterized in that, One of the external spline teeth (310) has a width along the circumference of the drive shaft (300) that is a preset circumferential distance; When the main drive device over-rotates, the external spline tooth (310) with a width of a preset circumferential distance along the circumferential direction of the drive shaft (300) breaks.
10. A transmission method for a coupling, employing the coupling as described in any one of claims 1 to 9, characterized in that, Includes the following steps: The first connecting end of the drive shaft (300) is splinedly connected to the first connecting part (100) provided on the main drive device, and the second connecting end of the drive shaft (300) is splinedly connected to the second connecting part (200) provided on the slave drive device; Start the main drive device, and drive the slave drive device to run together through the transmission shaft (300); The first connecting end of the drive shaft (300) moves radially relative to the first connecting portion (100) along the drive shaft (300), and the second connecting end of the drive shaft (300) moves radially relative to the second connecting portion (200) along the drive shaft (300).