Scroll type coupler

Abstract

The utility model discloses a scroll type coupler which comprises a first shaft sleeve, a second shaft sleeve and a scroll elastic connecting piece. A first shaft groove is formed in one end of the first shaft sleeve, and the other end of the first shaft sleeve is connected with the center of the scroll elastic connecting piece. A second shaft groove is formed in one end of the second shaft sleeve, and the other end of the second shaft sleeve is connected with the outer edge part of the scroll elastic connecting piece. The first shaft sleeve rotates to drive the scroll elastic connecting piece to be pre-tightened and rotate, and then the second shaft sleeve is driven to rotate. According to the utility model, the scroll elastic part is used as a middle transmission connecting part, so that the coupling has wider eccentric error accommodating capacity and better wear eccentric error self-adaptive capacity, the mounting difficulty of the coupling is reduced, and the production continuity is effectively guaranteed. In addition, the device also has the advantages of simple structure, ingenious design, low cost investment, convenience in installation, good transmission effect, wide application range, good stability and practicability and the like.

Description

Technical Field

[0001] This utility model relates to a coupling, specifically a spiral type coupling, and belongs to the technical field of mechanical transmission equipment. Background Technology

[0002] Couplings belong to the category of general-purpose mechanical components. They are mechanical parts used to connect two shafts (driving shaft and driven shaft) in different mechanisms, enabling them to rotate together and transmit torque. In high-speed, heavy-load power transmission, some couplings also serve to buffer, dampen vibrations, and improve the dynamic performance of the shaft system. A coupling generally consists of two halves, connected to the driving shaft and driven shaft respectively. Most power machines are connected to working machines via couplings, making them the most commonly used connecting components in the shaft transmission of mechanical products. In the late 20th century, the development of coupling products both domestically and internationally was rapid. For most designers, selecting the appropriate coupling from the numerous varieties and varying performance characteristics to meet machine requirements has always been a challenging problem. Commonly used couplings include diaphragm couplings, gear couplings, swivel couplings, sliding block couplings, drum gear couplings, universal couplings, safety couplings, flexible couplings, and serpentine spring couplings, etc.

[0003] With technological advancements, the precision requirements for couplings are becoming increasingly stringent. Since the drive and driven shafts are often rigidly connected to the coupling, insufficient alignment can lead to ineffective elimination of radial forces caused by eccentricity during high-speed rotation. This results in significant polarization and, in severe cases, the risk of shaft breakage. For high-precision equipment, the maximum permissible eccentricity error is often only a few micrometers, resulting in a narrow tolerance range and significant installation difficulties. In actual production, due to various uncontrollable factors, the drive shaft of the power unit and the driven shaft of the working machine are often misaligned. Errors can range from several millimeters to tens of micrometers. Even after adjustment to within the ideal error range, prolonged operation can cause the eccentricity error to gradually increase due to mechanical vibration or wear. This necessitates stopping the machine for adjustment. It's important to note that this increase in error during operation is often difficult to detect and promptly correct, typically requiring periodic shutdowns for inspection and adjustment, severely impacting normal production operations. Utility Model Content

[0004] To address the problems of existing couplings, such as difficulty in precise installation, low tolerance for eccentricity error, and the need for periodic downtime for adjustment, this utility model provides a scroll-type coupling. This coupling connects two bushings via a scroll-type elastic connector, enabling rotational transmission between the two bushings while maintaining a larger tolerance range for eccentricity error. This significantly improves the coupling's application range and greatly reduces its installation difficulty. Furthermore, it exhibits considerable self-adaptive properties to the phenomenon of increasing eccentricity error during operation. It boasts advantages such as simple structure, stable operation, and strong practicality.

[0005] To achieve the above-mentioned technical objectives, the technical solution adopted by this utility model is specifically as follows:

[0006] A scroll coupling includes a first bushing, a second bushing, and a scroll elastic connecting member. One end of the first bushing has a first shaft groove, and its other end is connected to the center of the scroll elastic connecting member. One end of the second bushing has a second shaft groove, and its other end is connected to the outer edge of the scroll elastic connecting member. Rotation of the first bushing drives the scroll elastic connecting member to pre-tighten and rotate, thereby causing the second bushing to rotate.

[0007] Preferably, the spiral elastic connector is formed by spirally winding a long strip of connecting material in a clockwise or counterclockwise direction within a plane. Specifically, one end of the long strip of connecting material is bent into a straight line to form a central connecting portion, and the other end is bent into a semi-circular shape to form an outer connecting portion. The portion between the central connecting portion and the outer connecting portion is spirally wound around the outside of the central connecting portion multiple times from the inside out to form the spiral body. The central connecting portion is connected to one end of the first bushing, and the outer connecting portion is connected to one end of the second bushing.

[0008] Preferably, the elongated connecting material is an elongated metal sheet or an elongated metal wire.

[0009] Preferably, a connecting shaft protrudes axially from the end of the first bushing opposite to the first shaft groove. A radial connecting seam is formed on the connecting shaft for the central connecting portion to pass through, meaning the connecting shaft is connected to the central connecting portion via the radial connecting seam. Preferably, the radial connecting seam extends axially through the entire connecting shaft, thus dividing the connecting shaft axially into two symmetrical half-shafts.

[0010] Preferably, the protruding end of the connecting shaft extends axially and passes through the bottom of the second shaft groove before connecting with a limiting mechanism located at the bottom of the second shaft groove.

[0011] Preferably, a limiting groove is provided at the bottom of the second shaft groove, and a limiting mechanism is provided in the limiting groove. The protruding end of the connecting shaft extends into the limiting groove and connects with the limiting mechanism.

[0012] Preferably, the limiting mechanism is a limiting nut, and the limiting nut and the protruding end of the connecting shaft are connected by a thread, welding or bonding.

[0013] Preferably, an elastic washer is provided between the limiting nut and the second bushing. Preferably, the elastic washer is a wave-shaped spring.

[0014] Preferably, an axially recessed fitting groove is provided at the end of the second bushing opposite to the second shaft groove. The groove wall of the fitting groove has a fitting interface corresponding to the outer edge connecting portion. The spiral elastic connector is integrally placed within the fitting groove, and its outer edge connecting portion is embedded into the fitting interface.

[0015] Preferably, an annular limiting sleeve extending toward the second bushing is provided at the end face edge of the first bushing away from the first bushing groove. The end of the second bushing away from its second bushing groove is fitted into the annular limiting sleeve.

[0016] Preferably, the coupling includes two or more spiral elastic connectors distributed in series along the axial direction, and at least one of the spiral elastic connectors has a spiral direction opposite to that of the other spiral elastic connectors.

[0017] Preferably, spline grooves, threads, or bolt holes for connecting to external shafts are independently provided on the groove walls of the first shaft groove and / or the second shaft groove.

[0018] In this invention, the two bushings of the coupling are no longer connected in a traditional fixed rigid manner, but are connected in a semi-rigid manner with a certain elastic change in the radial direction through a spiral elastic element (such as a planar spiral spring). Specifically, the other end of the bushing connected to the external power shaft (such as the first bushing of this invention) is connected to the center of the spiral elastic element, while the other end of the bushing connected to the external working shaft (such as the second bushing of this invention) is connected to the outer edge of the spiral elastic element. The external power shaft drives the first bushing to rotate. During the rotation of the first bushing, the spiral elastic element gradually rotates and retracts towards its center. After rotating to a certain extent, it can drive the second bushing to rotate, and then drive the external working shaft to rotate through the rotation of the second bushing. In this process, because the spiral elastic element has a certain degree of elasticity in the radial direction, when used as the connecting part of the two bushings of the coupling, it can tolerate a relatively larger eccentricity error between the shaft centers of the two external shafts respectively fitted by the two bushings. Under this condition, the connection of the two external shafts can still be achieved well without the need for overall adjustment of the system position of the two external shafts (in actual working conditions, due to various reasons, the position of the system where the external shafts are located is fixed and cannot be adjusted), significantly reducing the installation difficulty of the coupling. Furthermore, because the spiral elastic element has a certain eccentricity error tolerance in the radial direction, it can well adapt to the phenomenon of increased eccentricity error due to long-term use without frequent downtime for adjustments (generally, replacing worn parts). This ensures the continuity of production and also extends the service life of the parts, greatly reducing equipment investment costs.

[0019] In this invention, the spiral elastic connector is typically formed by spirally winding a long strip of metal sheet or wire in a clockwise or counterclockwise direction within a plane. Using the long strip of metal sheet or wire as the main material to form a spiral spring structure allows it to have a certain deformation space in the radial direction, while maintaining considerable rigidity after continuous rotation towards the center, thus meeting the requirements of transmission.

[0020] In this invention, a protruding connecting shaft on the first bushing passes through the second bushing and extends to the bottom of the second shaft groove, where it is connected by a limiting mechanism. This limiting mechanism locks the connecting shaft, effectively preventing axial displacement between the first and second bushings, thus ensuring the stability of the connection between the first bushing and the scroll elastic element. It also stably confines the scroll elastic element within the fitting groove of the second bushing, preventing axial twisting of the scroll elastic element from affecting its efficiency. Furthermore, the limiting mechanism applies a certain axial force to both the first and second bushings, providing auxiliary transmission during the high-speed rotation of the second bushing, thereby reducing the transmission load on the scroll elastic element.

[0021] In this invention, the limiting mechanism is generally a limiting nut, which is connected to the protruding end of the connecting shaft by a threaded connection, welding, or bonding. An elastic washer is also provided between the limiting nut and the second bushing. By providing the elastic washer, it serves two purposes: firstly, it reduces frictional wear between the limiting nut and the second bushing; secondly, it absorbs excess axial force and mitigates axial impact.

[0022] In this invention, by providing multiple parallel spiral elastic elements between the first and second bushings, and by having at least one spiral elastic element with a spiral direction opposite to that of the other spiral elastic elements, the coupling can simultaneously perform both forward and reverse rotation transmission, thereby further expanding its application range. For example, when this invention has two scroll elastic connectors rotating in opposite directions (one clockwise for pre-tightening rotation, and the other counterclockwise for pre-tightening rotation), when the first bushing rotates clockwise, it can only drive the second bushing to rotate clockwise through the clockwise pre-tightening scroll elastic connector. At this time, although the counterclockwise pre-tightening scroll elastic connector follows the clockwise rotation, it does not have a pre-tightening effect and its rotation is basically ineffective (does not affect the transmission). Conversely, when the first bushing rotates counterclockwise, it will drive the second bushing to rotate counterclockwise through the counterclockwise pre-tightening scroll elastic connector. At this time, although the clockwise pre-tightening scroll elastic connector follows the counterclockwise rotation, it does not have a pre-tightening effect and its rotation is also basically ineffective (does not affect the transmission). That is, by setting at least two scroll elastic connectors with opposite pre-tightening rotation directions, the shortcomings of scroll elastic connectors with single-direction rotation pre-tightening can only be rotated and pre-tightened in one direction, thereby improving the application scope of this utility model.

[0023] Compared with the prior art, the beneficial technical effects of this utility model are as follows:

[0024] 1. The coupling of this utility model uses a spiral elastic element as an intermediate transmission connection component, which makes the coupling have a wide tolerance for eccentric error and a good self-adaptive ability for wear eccentric error, reducing the installation difficulty of the coupling and effectively ensuring the continuity of production.

[0025] 2: The coupling of this utility model has the advantages of simple structure, ingenious design, low cost, convenient installation, good transmission effect and wide application range. In addition, it also has excellent stability and practicality. Attached Figure Description

[0026] Figure 1This is a schematic cross-sectional view of the coupling of this utility model.

[0027] Figure 2 This is a schematic diagram of the axial structure of the coupling of this utility model.

[0028] Figure 3 This is a schematic diagram of the structure of the spiral elastic connector of this utility model.

[0029] Figure 4 This is a planar comparison diagram of multiple spiral elastic connectors with opposite spiral directions according to this utility model.

[0030] Figure 5 This is a three-dimensional view of the coupling of this utility model.

[0031] Figure 6 This is a physical image of the spiral elastic connector of this utility model.

[0032] Figure 7 This is a schematic diagram of the structure of a spiral coupling of the present invention, which includes two spiral elastic connecting parts.

[0033] Reference numerals: 1: First bushing; 101: First shaft groove; 102: Connecting shaft; 103: Radial connecting seam; 104: Annular limiting sleeve; 2: Second bushing; 201: Second shaft groove; 202: Limiting mechanism; 203: Limiting groove; 204: Elastic gasket; 205: Insertion groove; 206: Insertion interface; 3: Scroll elastic connector; 301: Central connecting part; 302: Outer edge connecting part; 303: Scroll body. Detailed Implementation

[0034] The technical solution of this utility model is illustrated below. The scope of protection of this utility model includes, but is not limited to, the following embodiments.

[0035] A scroll coupling includes a first bushing 1, a second bushing 2, and a scroll elastic connector 3. One end of the first bushing 1 has a first shaft groove 101, and its other end is connected to the center of the scroll elastic connector 3. One end of the second bushing 2 has a second shaft groove 201, and its other end is connected to the outer edge of the scroll elastic connector 3. Rotation of the first bushing 1 drives the scroll elastic connector 3 to pre-tighten and rotate, thereby causing the second bushing 2 to rotate.

[0036] Preferably, the spiral elastic connector 3 is formed by spirally winding a long strip of connecting material in a clockwise or counterclockwise direction in a plane. Specifically, one end of the long strip of connecting material is bent into a straight line to form a central connecting portion 301, and the other end is bent into a semi-circular shape to form an outer edge connecting portion 302. The portion between the central connecting portion 301 and the outer edge connecting portion 302 is spirally wound around the outside of the central connecting portion 301 from the inside out multiple times to form a spiral body 303. The central connecting portion 301 is connected to one end of the first bushing 1, and the outer edge connecting portion 302 is connected to one end of the second bushing 2.

[0037] Preferably, the elongated connecting material is an elongated metal sheet or an elongated metal wire.

[0038] Preferably, a connecting shaft 102 protrudes axially from one end of the first bushing 1 opposite to the first shaft groove 101. A radial connecting slot 103 is formed on the connecting shaft 102 for the central connecting part 301 to pass through, meaning the connecting shaft 102 is connected to the central connecting part 301 via the radial connecting slot 103. Preferably, the radial connecting slot 103 extends through the entire connecting shaft 102 axially, thus dividing the connecting shaft 102 axially into two symmetrical half-shafts.

[0039] Preferably, the protruding end of the connecting shaft 102 extends axially and passes through the bottom of the second shaft groove 201, where it is connected to the limiting mechanism 202 located at the bottom of the second shaft groove 201.

[0040] Preferably, a limiting groove 203 is provided at the bottom of the second shaft groove 201, and a limiting mechanism 202 is provided in the limiting groove 203. The protruding end of the connecting shaft 102 extends into the limiting groove 203 and is connected to the limiting mechanism 202.

[0041] Preferably, the limiting mechanism 202 is a limiting nut, and the limiting nut and the protruding end of the connecting shaft 102 are connected by a thread, welding or bonding.

[0042] Preferably, an elastic washer 204 is provided between the limiting nut and the second bushing 2. Preferably, the elastic washer 204 is a wave-shaped spring.

[0043] Preferably, an axially recessed fitting groove 205 is provided at the end of the second bushing 2 opposite to the second shaft groove 201. The groove wall of the fitting groove 205 is provided with a fitting interface 206 corresponding to the outer edge connecting part 302. The spiral elastic connector 3 is integrally placed in the fitting groove 205, and its outer edge connecting part 302 is embedded in the fitting interface 206.

[0044] Preferably, an annular limiting sleeve 104 extending toward the second bushing 2 is provided at the end face edge of the first bushing 1 away from the first bushing groove 101. The end of the second bushing 2 away from its second bushing groove 201 is fitted into the annular limiting sleeve 104.

[0045] Preferably, the coupling includes two or more spiral elastic connectors 3 arranged in series along the axial direction, and at least one of the spiral elastic connectors 3 has a spiral direction opposite to that of the other spiral elastic connectors 3.

[0046] Preferably, spline grooves, threads, or bolt holes for connecting to external shafts are independently provided on the groove walls of the first shaft groove 101 and / or the second shaft groove 201.

[0047] Example 1

[0048] like Figure 1 , 2 As shown in Figure 5, a scroll coupling includes a first bushing 1, a second bushing 2, and a scroll elastic connector 3. One end of the first bushing 1 has a first shaft groove 101, and its other end is connected to the center of the scroll elastic connector 3. One end of the second bushing 2 has a second shaft groove 201, and its other end is connected to the outer edge of the scroll elastic connector 3. The rotation of the first bushing 1 drives the scroll elastic connector 3 to pre-tighten and rotate, thereby causing the second bushing 2 to rotate.

[0049] Example 2

[0050] like Figure 3 , 6 As shown, Embodiment 1 is repeated, except that the spiral elastic connector 3 is formed by spirally winding a long strip of connecting material in a clockwise or counterclockwise direction in a plane. Specifically, one end of the long strip of connecting material is bent into a straight line to form a central connecting part 301, and the other end is bent into a semi-circular shape to form an outer edge connecting part 302. The portion between the central connecting part 301 and the outer edge connecting part 302 is spirally wound around the outside of the central connecting part 301 from the inside out multiple times to form a spiral body 303. The central connecting part 301 is connected to one end of the first bushing 1, and the outer edge connecting part 302 is connected to one end of the second bushing 2.

[0051] Example 3

[0052] Repeat Example 2, except that the long strip connecting material is a long strip of metal wire.

[0053] Example 4

[0054] Repeat Example 2, except that the elongated connecting material is an elongated metal sheet.

[0055] Example 5

[0056] like Figure 1 As shown, embodiment 4 is repeated, except that a connecting shaft 102 protrudes axially from one end of the first bushing 1 away from the first shaft groove 101. A straight radial connecting seam 103 is provided on the connecting shaft 102 for the central connecting part 301 to pass through, that is, the connecting shaft 102 is connected to the central connecting part 301 through the radial connecting seam 103.

[0057] Example 6

[0058] Example 5 is repeated, except that the radial connecting seam 103 extends through the entire connecting shaft 102 along its axial direction, that is, the connecting shaft 102 is divided into two symmetrical half-shafts along its axial direction by the radial connecting seam 103.

[0059] Example 7

[0060] The embodiment 6 is repeated, except that the protruding end of the connecting shaft 102 extends axially and passes through the bottom of the second shaft groove 201, where it is connected to the limiting mechanism 202 located at the bottom of the second shaft groove 201.

[0061] Example 8

[0062] Repeat embodiment 7, except that a limiting groove 203 is provided at the bottom of the second shaft groove 201, and a limiting mechanism 202 is provided in the limiting groove 203. The protruding end of the connecting shaft 102 extends into the limiting groove 203 and is connected to the limiting mechanism 202.

[0063] Example 9

[0064] The embodiment 8 is repeated, except that the limiting mechanism 202 is a limiting nut, and the limiting nut and the protruding end of the connecting shaft 102 are connected by a thread.

[0065] Example 10

[0066] Repeat Example 9, except that an elastic washer 204 is also provided between the limiting nut and the second bushing 2.

[0067] Example 11

[0068] Repeat Example 10, except that the elastic pad 204 is a wave-shaped spring.

[0069] Example 12

[0070] The embodiment 11 is repeated, except that an axially recessed fitting groove 205 is provided at the end of the second bushing 2 opposite to the second shaft groove 201. A fitting interface 206 corresponding to the outer edge connecting portion 302 is formed on the groove wall of the fitting groove 205. The spiral elastic connector 3 is integrally placed within the fitting groove 205, and its outer edge connecting portion 302 is embedded into the fitting interface 206.

[0071] Example 13

[0072] The embodiment 12 is repeated, except that an annular limiting sleeve 104 extending toward the second sleeve 2 is provided at the end face edge of the first sleeve 1 away from the first shaft groove 101. The end of the second sleeve 2 away from its second shaft groove 201 is fitted into the annular limiting sleeve 104.

[0073] Example 14

[0074] like Figure 4 , 7 As shown, embodiment 13 is repeated, except that the coupling includes two spiral elastic connectors 3 distributed in series along the axial direction, and the spiral direction of one of the spiral elastic connectors 3 is clockwise, while the spiral direction of the other spiral elastic connector 3 is counterclockwise.

[0075] Example 15

[0076] The embodiment 14 is repeated, except that the coupling includes three spiral elastic connectors 3 arranged in series along the axial direction, and two of the spiral elastic connectors 3 have a spiral direction of clockwise, while the spiral direction of the other spiral elastic connector 3 is counterclockwise.

[0077] Example 16

[0078] The embodiment 14 is repeated, except that spline grooves for connecting with external shafts are independently provided on the groove walls of the first shaft groove 101 and the second shaft groove 201.

[0079] When using the scroll coupling of this invention, the drive shaft and transmission shaft to be connected to the outside are fixedly connected to the first shaft groove 101 and the second shaft groove 201, respectively. Then, the drive shaft is driven to rotate. During the rotation of the drive shaft, the first bushing 1 rotates, and the central connecting part 301 is tightened through the radial connecting seam 103 on the connecting shaft 102. After the scroll elastic connector 3 is tightened, the second bushing 2 can be driven to rotate through the outer edge connecting part 302 and the insert 206, and further drive the transmission shaft to rotate. It should be noted that when the coupling includes at least two scroll elastic connectors 3 distributed in series along the axial direction, and the scroll direction of at least one scroll elastic connector 3 is opposite to the scroll direction of the other scroll elastic connectors 3, the forward and reverse rotation of the drive shaft can be satisfied, and the transmission shaft can be driven to rotate synchronously in both directions.

Claims

1. A spiral coupling, characterized in that: The coupling includes a first bushing (1), a second bushing (2), and a spiral elastic connector (3); one end of the first bushing (1) is provided with a first shaft groove (101), and the other end is connected to the center of the spiral elastic connector (3); one end of the second bushing (2) is provided with a second shaft groove (201), and the other end is connected to the outer edge of the spiral elastic connector (3); the first bushing (1) rotates to drive the spiral elastic connector (3) to pre-tighten and rotate, thereby driving the second bushing (2) to rotate.

2. The coupling according to claim 1, characterized in that: The spiral elastic connector (3) is formed by spiraling a strip of connecting material in a clockwise or counterclockwise direction in a plane; one end of the strip of connecting material is bent into a straight line to form a central connecting part (301), and the other end is bent into a semi-circular shape to form an outer edge connecting part (302). The part between the central connecting part (301) and the outer edge connecting part (302) spirals around the outside of the central connecting part (301) multiple times from the inside to the outside to form a spiral body (303); the central connecting part (301) is connected to one end of the first bushing (1), and the outer edge connecting part (302) is connected to one end of the second bushing (2).

3. The coupling according to claim 2, characterized in that: The elongated connecting material is an elongated metal sheet or an elongated metal wire.

4. The coupling according to claim 2, characterized in that: A connecting shaft (102) protrudes axially from one end of the first bushing (1) away from the first shaft groove (101); a straight radial connecting seam (103) is provided on the connecting shaft (102) for the central connecting part (301) to pass through, that is, the connecting shaft (102) is connected to the central connecting part (301) through the radial connecting seam (103).

5. The coupling according to claim 4, characterized in that: The radial connecting seam (103) runs through the entire connecting shaft (102) along its axial direction, that is, the connecting shaft (102) is divided into two symmetrical half-shafts along its axial direction by the radial connecting seam (103).

6. The coupling according to claim 5, characterized in that: The protruding end of the connecting shaft (102) extends axially and passes through the bottom of the second shaft groove (201) before connecting with the limiting mechanism (202) located at the bottom of the second shaft groove (201).

7. The coupling according to claim 6, characterized in that: A limiting groove (203) is provided at the bottom of the second shaft groove (201), and a limiting mechanism (202) is provided in the limiting groove (203). The protruding end of the connecting shaft (102) extends into the limiting groove (203) and connects with the limiting mechanism (202).

8. The coupling according to claim 7, characterized in that: The limiting mechanism (202) is a limiting nut, and the limiting nut and the protruding end of the connecting shaft (102) are connected by a thread, welding or bonding.

9. The coupling according to claim 8, characterized in that: An elastic washer (204) is also provided between the limit nut and the second bushing (2).

10. The coupling according to claim 9, characterized in that: The elastic pad (204) is a wave-shaped elastic pad.

11. The coupling according to any one of claims 1-10, characterized in that: A recessed axial groove (205) is provided at one end of the second bushing (2) away from the second shaft groove (201); an insertion interface (206) corresponding to the outer edge connection part (302) is provided on the groove wall of the insertion groove (205); the spiral elastic connector (3) is integrally placed in the insertion groove (205), and its outer edge connection part (302) is embedded in the insertion interface (206).

12. The coupling according to any one of claims 1-10, characterized in that: An annular limiting sleeve (104) extending toward the second sleeve (2) is provided on the end face edge of the first sleeve (1) away from the first shaft groove (101); the end of the second sleeve (2) away from its second shaft groove (201) is sleeved in the annular limiting sleeve (104).

13. The coupling according to any one of claims 1-10, characterized in that: The coupling includes two or more spiral elastic connectors (3) arranged in series along the axial direction, and at least one of the spiral elastic connectors (3) has a spiral direction opposite to that of the other spiral elastic connectors (3).

14. The coupling according to any one of claims 1-10, characterized in that: The first shaft groove (101) and / or the second shaft groove (201) are respectively provided with spline grooves, threads or bolt holes for connecting with external shafts.

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