Multidirectional vibration reduction supporting rod suitable for offshore floating type structure

Abstract

The invention discloses a multidirectional vibration reduction supporting rod suitable for an offshore floating structure. The multidirectional vibration reduction supporting rod comprises a left supporting assembly hinged to the floating structure, a right supporting assembly hinged to the floating structure and a shell assembly wrapping the left supporting assembly and the right supporting assembly and used for being connected with the left supporting assembly and the right supporting assembly. The left supporting assembly and the right supporting assembly each comprise an end connecting piece, a U-shaped plug pin hinged to the end connecting piece, a plug pin connector which is connected with the U-shaped plug pin in a sleeved mode and is of a hollow structure, a steel wire mooring rope which is arranged in the plug pin connector in a penetrating mode and extends out, and vibration reduction rubber sleeves which are sequentially arranged on the steel wire mooring rope in a penetrating mode. The device comprises a first belleville spring, a belleville spring buffer piece, a second belleville spring, a stress plate, a third belleville spring, a force application fixing sleeve and a force application thread cap connected with an external thread at the tail end of a steel wire rope. The multi-degree-of-freedom vibration reduction device can move along with a floating structure in a multi-degree-of-freedom mode, horizontal and vertical vibration reduction can be achieved, and multi-direction vibration borne by the floating structure is effectively relieved.

Description

Technical Field

[0001] The invention relates to the technical field of offshore vibration reduction devices, and in particular to a multi-directional vibration reduction support rod suitable for offshore floating structures. Background Art

[0002] The multi-directional vibration damping rod of the floating structure is a vibration damping device used in marine engineering, which is mainly used to stabilize and reduce the vibration and shaking of floating bridges and other multi-module floating structures at sea in wind and waves. Marine floating structures are usually used in marine transportation, marine oil and gas extraction, wind power generation, offshore aquaculture and other scenarios, and the wind, waves and tides in the marine environment will produce significant multi-directional impact and vibration on marine floating structures.

[0003] However, there are many problems with the existing vibration reduction technology for floating structures. Traditional vibration reduction structures are usually composed of simple mass blocks or liquid dampers. Although they can play a certain role in vibration reduction, they are complex in structure and can only be effective in the axial direction. They are not effective against horizontal vibration and instantaneous impact force. In addition, existing vibration reduction designs usually lack the ability to adapt to multi-directional vibrations, and under huge loads, the buffering capacity of the structure is limited, and components are prone to failure. Especially in extreme sea conditions, steel cables or connecting chains are prone to breakage, causing the entire floating structure to become unstable or even capsize, causing significant economic losses and safety risks.

[0004] Therefore, it is urgent to solve the above problems. Summary of the invention

[0005] Purpose of the invention: The purpose of the present invention is to provide a multi-directional vibration-damping support rod suitable for offshore floating structures. The present invention can move with the multiple degrees of freedom of the floating structure, and can achieve horizontal and vertical vibration reduction at the same time, effectively alleviating the multi-directional vibrations that the floating structure is subjected to in severe sea conditions.

[0006] Technical solution: To achieve the above objectives, the present invention discloses a multi-directional vibration-damping support rod suitable for an offshore floating structure, comprising a left support assembly hinged to the floating structure, a right support assembly hinged to the floating structure, and a shell assembly covered on the outside of the left and right support assemblies and used to connect the left and right support assemblies, wherein the left support assembly and the right support assembly both include an end connector, a U-shaped pin hinged to the end connector, a pin connector sleeved with the U-shaped pin and having a hollow structure, a steel wire rope inserted in and extending from the pin connector and having an external thread at the tail end, a vibration-damping rubber sleeve sequentially inserted on the steel wire rope, a first butterfly spring, a butterfly spring buffer, a second butterfly spring, a force plate, a third butterfly spring, a force fixing sleeve, and a force threaded cap connected to the external thread at the tail end of the steel wire rope.

[0007] Optionally, at least two vertical vibration damping rings are arranged at intervals in the inner cavity of the plug connector, the vertical vibration damping rings are passed through the steel wire cable, and each vertical vibration damping ring is provided with an Archimedean spiral groove.

[0008] Optionally, the plug connector includes a plug connecting sleeve having claws at both ends, a reinforcing sleeve sleeved on the outside of the plug connecting sleeve, and a connecting end located at the rear end of the plug connecting sleeve, wherein an Archimedean spiral groove is provided on the front end surface of the connecting end, and the rear end surface of the connecting end abuts against the vibration-damping rubber sleeve.

[0009] Optionally, the shell assembly includes a small shell, a vibration-damping connector, a large shell, a vibration-damping gasket, an intermediate shell, a vibration-damping gasket, a large shell, a vibration-damping connector and a small shell that are connected in sequence.

[0010] Optionally, one end of the small housing is connected to the flange surface of the vibration-damping connector via a flange, and the other end of the small housing is sleeved on the plug connector and has an interference fit with the plug connector.

[0011] Optionally, the vibration damping connecting member includes a vibration damping connecting cylinder, a flange surface located on the outside of the vibration damping connecting cylinder, a front vibration damping ring located at the front end of the vibration damping connecting cylinder, and a rear connecting ring located at the front end of the vibration damping connecting cylinder, wherein the front vibration damping ring is provided with an Archimedean spiral groove, and the step surface of the vibration damping rubber sleeve abuts against the rear connecting ring.

[0012] Optionally, the butterfly spring buffer comprises a buffer tube and a buffer spacer ring located in the buffer tube, wherein the ends of the first butterfly spring and the second butterfly spring are respectively abutted against two side surfaces of the buffer spacer ring.

[0013] Optionally, the force-applying fixing sleeve includes a fixing sleeve mounted on the steel wire cable and a fixing cover located at the end of the fixing sleeve and covering a third butterfly spring, the end of the third butterfly spring abuts against the end of the fixing sleeve, and the force-applying threaded cap presses the other end of the fixing sleeve; a rubber sleeve is mounted on the outer side of the fixing sleeve, one end of the rubber sleeve abuts against the end face of the fixing cover, and the other end of the rubber sleeve abuts against the vibration-damping gasket of the shell assembly.

[0014] Optionally, the U-shaped pin of the left support assembly is hinged to the end connector of the left support assembly through a first hinge axis, the end connector of the left support assembly is hinged to the floating structure through a left hinge axis, and the directions of the left hinge axis and the first hinge axis are perpendicular to each other; the U-shaped pin of the right support assembly is hinged to the end connector of the right support assembly through a second hinge axis, the end connector of the right support assembly is hinged to the floating structure through a right hinge axis, and the directions of the right hinge axis and the second hinge axis are perpendicular to each other.

[0015] Optionally, the loss factors of the first butterfly spring, the second butterfly spring and the third butterfly spring are greater than 0.06.

[0016] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0017] (1) The present invention realizes safe, reliable and efficient connection of two floating structures under heavy loads. The butterfly spring is used as a buffer structure, which has huge bearing capacity and buffering capacity, and well solves the problem that the traditional connection structure has poor bearing capacity and the connection structure is damaged and broken due to the huge load generated instantly in high sea conditions or severe extreme weather.

[0018] (2) The present invention adds vibration-damping rubber to the connection structure, further improving the buffering capacity of the structure, while effectively limiting the degree of freedom of the structure in high-amplitude vibration, thereby avoiding excessive shaking of the floating platform under severe vibration; not only enhancing the stability of the floating platform, but also reducing the impact of vibration on the equipment and personnel on the platform, thereby improving the safety of offshore operations;

[0019] (3) The present invention realizes a multi-degree-of-freedom connection mode, which provides great flexibility under complex sea conditions. Through two mutually perpendicular hinge axes, the vibration damping rod can easily cope with vibrations and impacts in multiple directions, ensuring the stability of the floating structure in harsh environments. Compared with the traditional single-degree-of-freedom connection, the present invention greatly improves the impact resistance and adaptability of the connection structure, avoiding structural damage caused by excessive connection rigidity. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of the present invention;

[0021] Figure 2 It is a partial cross-sectional view of the present invention;

[0022] Figure 3 It is a schematic diagram of the structure of the vertical vibration damping ring in the present invention;

[0023] Figure 4 It is a schematic diagram of the structure of the plug connector in the present invention;

[0024] Figure 5 It is a structural schematic diagram of the connecting end in the present invention;

[0025] Figure 6 It is a structural schematic diagram of the butterfly spring buffer in the present invention;

[0026] Figure 7 It is a structural schematic diagram of the force-applying fixing sleeve in the present invention;

[0027] Figure 8 It is a schematic diagram of the structure of the vibration-damping connecting piece in the present invention. DETAILED DESCRIPTION

[0028] The technical solution of the present invention is further described below in conjunction with the accompanying drawings.

[0029] like Figure 1 As shown, the present invention discloses a multi-directional vibration-damping support rod suitable for an offshore floating structure, comprising a left hinge shaft 1, a left support assembly, a right support assembly and a shell assembly, wherein the left support assembly is hinged to the floating structure through the left hinge shaft 1, the right support assembly is hinged to the floating platform through the right hinge shaft 23, and the directions of the left hinge shaft 1 and the right hinge shaft 23 are inconsistent; or the right support assembly is hinged to the floating structure through the right hinge shaft 23, and the left support assembly is hinged to the fixed structure through the left hinge shaft 1; or the right support assembly is hinged to the fixed structure through the right hinge shaft 23, and the left support assembly is hinged to the floating structure through the left hinge shaft 1. The shell assembly is coated on the outside of the left and right support assemblies, the left support assembly and the right support assembly are respectively inserted into the two ends of the shell assembly, the outer wall of the left support assembly is interference fit with one end of the shell assembly, and the outer wall of the right support assembly is interference fit with the other end of the shell assembly.

[0030] like Figure 2 As shown, the left support assembly and the right support assembly each include an end connector 2, a U-shaped pin 3, a pin connector 4, a steel cable 5, a vibration-damping rubber sleeve 6, a first butterfly spring 7, a butterfly spring buffer 8, a second butterfly spring 9, a force plate 10, a third butterfly spring 11, a force-applying fixing sleeve 12, a force-applying threaded cap 13, a vertical vibration-damping ring 14, and a rubber sleeve 21. The vibration-damping rubber sleeve 6, the butterfly spring buffer 8, and the rubber sleeve 21 are all rubber parts. The U-shaped pin of the left support assembly is hinged to the end connector 2 of the left support assembly through the first hinge shaft 22, the end connector 2 of the left support assembly is hinged to the floating structure through the left hinge shaft 1, and the left hinge shaft 1 and the first hinge shaft 22 are perpendicular to each other; the U-shaped pin of the right support assembly is hinged to the end connector 2 of the right support assembly through the second hinge shaft 24, the end connector 2 of the right support assembly is hinged to the floating structure through the right hinge shaft 23, and the right hinge shaft 23 and the second hinge shaft 24 are perpendicular to each other.

[0031] The plug connector 4 is sleeved with the U-shaped plug 3, the end of the U-shaped plug 3 has a cylindrical portion, the plug connector 4 has a hollow structure, and the cylindrical portion of the U-shaped plug 3 and the end of the plug connector 4 are interference fit. Figure 4 and Figure 5As shown, the plug connector 4 includes a claw 401, a plug connection sleeve 402, a reinforcement sleeve 403 and a connection end 404. Both ends of the plug connection sleeve 402 have claws 401. The reinforcement sleeve 403 is sleeved on the outside of the plug connection sleeve 402. The connection end 404 is located at the tail end of the plug connection sleeve 402, wherein the head end surface of the connection end 404 is provided with an Archimedes spiral groove 15, and the tail end surface of the connection end 404 is in contact with the vibration-damping rubber sleeve 6. The wire cable 5 is inserted into the plug connector, the wire cable 5 extends out of the plug connector, and the tail end of the wire cable 5 has an external thread. At least two vertical vibration-damping rings 14 are arranged in the inner cavity of the plug connector 4, and the vertical vibration-damping rings 14 are inserted on the wire cable 5. Each vertical vibration-damping ring 14 is provided with an Archimedes spiral groove 15, as shown in FIG. Figure 3 As shown. The formula of Archimedean spiral groove is:

[0032] X=(80+40t)cos(2πt)

[0033] Y=(80+40t)sin(2πt)

[0034] The design parameter t∈(1.4,2.5), X and Y are the coordinates of the points on the Archimedean spiral groove, and the groove width is 8% to 12% of the diameter of the vertical vibration damping ring.

[0035] There is a gap between the outer wall of the wire rope 5 and the inner wall of the vertical vibration-damping ring 14, and the outer wall of the vertical vibration-damping ring 14 is interference-fitted with the inner wall of the plug connector 4. The wire rope 5 is sequentially provided with a vibration-damping rubber sleeve 6, a first butterfly spring 7, a butterfly spring buffer 8, a second butterfly spring 9, a force-bearing plate 10, a third butterfly spring 11, a force-applying fixing sleeve 12 and a force-applying threaded cap 13. The force-applying threaded cap 13 is connected to the external thread at the tail end of the wire rope 5 and is tightened with a nut 25; the vibration-damping rubber sleeve 6, the first butterfly spring 7, the butterfly spring buffer 8, the second butterfly spring 9, the force-bearing plate 10, the third butterfly spring 11 and the force-applying fixing sleeve 12 are all arranged on the outer periphery of the wire rope 5 and are not connected and fixed to the wire rope 5. Figure 6 As shown, the butterfly spring buffer 8 includes a buffer cylinder 801 and a buffer spacer ring 802 located in the buffer cylinder 801, wherein the ends of the first butterfly spring 7 and the second butterfly spring 9 are respectively abutted against the two side surfaces of the buffer spacer ring 802. The loss factor of the first butterfly spring 7, the second butterfly spring 9 and the third butterfly spring 11 is greater than 0.06.

[0036] The housing assembly includes a small housing 16, a vibration-damping connector 17, a large housing 18, a vibration-damping gasket 19, an intermediate housing 20, a vibration-damping gasket 19, a large housing 18, a vibration-damping connector 17 and a small housing 16, which are connected in sequence. The outer wall of the housing assembly is also provided with a plurality of reinforcing ribs. One end of the small housing 16 is connected to the flange surface of the vibration-damping connector 17 through a flange, and the other end of the small housing 16 is sleeved on the plug connector 4 and has an interference fit with the plug connector 4. Figure 8 As shown, the vibration-damping connecting member 17 includes a vibration-damping connecting cylinder 1701, a flange surface 1702 located outside the vibration-damping connecting cylinder, a front vibration-damping ring 1703 located at the front end of the vibration-damping connecting cylinder, and a rear vibration-damping ring 1704 located at the front end of the vibration-damping connecting cylinder, wherein the front vibration-damping ring 1703 is provided with an Archimedean spiral groove 15, and the step surface of the vibration-damping rubber sleeve 6 abuts against the rear vibration-damping ring 1704;

[0037] The formula of Archimedean spiral groove is:

[0038] X=(80+40t)cos(2πt)

[0039] Y=(80+40t)sin(2πt)

[0040] The design parameter t∈(1.4,2.5), X and Y are the coordinates of the points on the Archimedean spiral groove, and the groove width is 8% to 12% of the diameter of the front vibration damping ring.

[0041] like Figure 7 As shown, the force-applying fixing sleeve 12 includes a fixing sleeve 1201 sleeved on the steel wire cable 5 and a fixing cover 1202 located at the end of the fixing sleeve and covering the third butterfly spring. The end of the third butterfly spring 11 abuts against the end of the fixing sleeve 1201, and the force-applying threaded cap 13 presses the other end of the fixing sleeve 1202. A rubber sleeve 21 is sleeved on the outer side of the fixing sleeve 1202, one end of the rubber sleeve 21 abuts against the end face of the fixing cover 1201, and the other end of the rubber sleeve 21 abuts against the vibration-damping gasket 19 of the shell assembly.

[0042] The left support assembly and the right support assembly are shock absorbers composed of multiple disc springs and rubber parts, which can absorb and resist vibration loads from both horizontal and vertical directions. The connection structure composed of a first hinge shaft and a second hinge shaft with directions perpendicular to each other connects the support rod to the floating structure or fixed platform, ensuring that the shock absorbing rod is firmly connected to the floating structure while ensuring that the support rod can move with multiple degrees of freedom of the floating structure. By combining disc springs with a connection structure with multiple degrees of freedom, the present invention can effectively alleviate the multi-directional vibrations that the floating structure is subjected to in severe sea conditions, greatly improving the stability and durability of the floating structure and reducing the possibility of structural fatigue damage.

[0043] During the working process of the present invention, when the floating structure is subjected to horizontal impact from ocean waves and wind, and a compressive force is generated on the shock absorbing rod, the impact load is first transmitted from the left hinge shaft 1 and the right hinge shaft 23 to the U-shaped pin 3 and the pin connector 4, and the vibration-damping rubber sleeve 6 is compressed through a slight slip of the pin connector 4. After the vibration-damping rubber sleeve 6 is compressed, pressure will be generated on the first butterfly spring 7. After being squeezed, the first butterfly spring 7 is deformed, and while relieving part of the pressure, the pressure is transmitted to the butterfly spring buffer 8 connecting the first butterfly spring 7 and the second butterfly spring 9, and then the pressure is transmitted to the second butterfly spring 9. Finally, the pressure is transmitted to the force plate 10, and shock absorption is performed through the deformation between the disc spring and the rubber.

[0044] During the working process of the present invention, when the floating structure is subjected to horizontal impact from ocean waves and wind, and tensile force is generated on the shock-absorbing rod, the impact load is first transmitted from the left hinge shaft 1 and the right hinge shaft 23 to the U-shaped pin 3 and the pin connector 4. The pin connector 4 is connected to the wire cable 5. At this time, the wire cable 5 is subjected to tension. Since the force-applying threaded cap 13 is screwed and connected to the wire cable 5, when the wire cable 5 is subjected to tension, part of the energy is absorbed and relieved, and the tension is transmitted to the force-applying fixing sleeve 12 through the force-applying threaded cap 13. The slight slip of the force-applying fixing sleeve 12 transmits the tension to the third butterfly spring 11. The third butterfly spring 11 is deformed after being squeezed by external force, and transmits the pressure to the force-bearing plate 10 while relieving part of the pressure. The force-bearing plate 10 transmits the tension to the second butterfly spring 9 and the first spring 7, and shock absorption is performed through the deformation between the disc spring and the rubber.

[0045] In the working process of the present invention, when the floating structure is subjected to vertical impact from ocean waves and wind, the impact load is first transmitted from the left hinge shaft 1 and the right hinge shaft 23 to the U-shaped pin 3 and the pin connector 4. The pin connector 4 has two vertical shock absorbing rings 14 embedded therein. The vertical shock absorbing rings 14 are dug with Archimedes spiral grooves 15. In the vertical swing and vertical movement, the Archimedes spiral grooves can effectively absorb and disperse the vibration energy. When the vertical impact force is transmitted to the pin connector 4, the pin connector 4 is displaced in the vertical direction, and pressure is generated on the vertical shock absorbing ring 14. Through the gradual deformation of the Archimedes spiral grooves 15, the energy is gradually dispersed and absorbed, which can effectively reduce the instantaneous impact force. When the displacement of the plug connector 4 is too large, the vertical impact force will be transmitted to the vibration-damping rubber sleeve 6, and the vibration-damping rubber sleeve 6 is wrapped by the vibration-damping connecting piece 17. The impact energy will be transmitted to the vibration-damping connecting piece 17, and the vibration-damping connecting piece 17 is dug with Archimedean spiral grooves 15, which can effectively absorb and disperse vibration energy.

Claims

1. A multi-directional vibration-damping support rod suitable for an offshore floating structure, characterized in that: The invention comprises a left support assembly hinged to a floating structure, a right support assembly hinged to the floating structure, and a shell assembly covered on the outside of the left and right support assemblies and used to connect the left and right support assemblies, wherein the left support assembly and the right support assembly each comprise an end connector (2), a U-shaped latch (3) hinged to the end connector, a latch connector (4) sleeved with the U-shaped latch and having a hollow structure, a steel wire rope (5) inserted into the latch connector and extending out and having an external thread at the tail end, and a vibration-damping rubber sleeve (6) sequentially inserted into the steel wire rope, a first butterfly spring (7), a butterfly spring buffer (8), a second butterfly spring (9), a force plate (10), a third butterfly spring (11), a force fixing sleeve (12), and a force threaded cap (13) connected to the external thread at the tail end of the steel wire rope.

2. A multi-directional vibration-damping support rod suitable for offshore floating structures according to claim 1, characterized in that: At least two vertical vibration damping rings (14) are arranged in the inner cavity of the plug connector (4), and the vertical vibration damping rings (14) are inserted on the steel wire cable (5). Each vertical vibration damping ring (14) is provided with an Archimedean spiral groove (15), wherein the formula of the Archimedean spiral groove is: X=(80+40t)cos(2πt) Y=(80+40t)sin(2πt) The design parameter t∈(1.4,2.5), X and Y are the coordinates of the points on the Archimedean spiral groove.

3. The multi-directional vibration-damping support rod suitable for offshore floating structures according to claim 1, characterized in that: The plug connector (4) comprises a plug connection sleeve (402) having claws (401) at both ends, a reinforcing sleeve (403) sleeved on the outside of the plug connection sleeve, and a connecting end (404) located at the rear end of the plug connection sleeve, wherein an Archimedean spiral groove (15) is provided on the front end surface of the connecting end (404), and the rear end surface of the connecting end (404) abuts against the vibration-damping rubber sleeve (6).

4. The multi-directional vibration-damping support rod suitable for offshore floating structures according to claim 1, characterized in that: The housing assembly comprises a small housing (16), a vibration-damping connector (17), a large housing (18), a vibration-damping gasket (19), an intermediate housing (20), a vibration-damping gasket (19), a large housing (18), a vibration-damping connector (17) and a small housing (16) which are connected in sequence.

5. A multi-directional vibration-damping support rod suitable for offshore floating structures according to claim 4, characterized in that: One end of the small housing (16) is connected to the flange surface of the vibration-damping connector (17) via a flange, and the other end of the small housing (16) is sleeved on the plug connector (4) and is interference-fitted with the plug connector (4).

6. A multi-directional vibration-damping support rod suitable for offshore floating structures according to claim 4, characterized in that: The vibration-damping connecting member (17) comprises a vibration-damping connecting cylinder (1701), a flange surface (1702) located outside the vibration-damping connecting cylinder, a front vibration-damping ring (1703) located at the front end of the vibration-damping connecting cylinder, and a rear vibration-damping ring (1704) located at the front end of the vibration-damping connecting cylinder, wherein the front vibration-damping ring (1703) is provided with an Archimedean spiral groove (15), and the step surface of the vibration-damping rubber sleeve (6) abuts against the rear vibration-damping ring (1704); The formula of Archimedean spiral groove is: X=(80+40t)cos(2πt) Y=(80+40t)sin(2πt) The design parameter t∈(1.4,2.5), X and Y are the coordinates of the points on the Archimedean spiral groove.

7. The multi-directional vibration-damping support rod suitable for offshore floating structures according to claim 1, characterized in that: The butterfly spring buffer (8) comprises a buffer cylinder (801) and a buffer spacer ring (802) located in the buffer cylinder, wherein the ends of the first butterfly spring (7) and the second butterfly spring (9) respectively abut against the two side surfaces of the buffer spacer ring (802).

8. The multi-directional vibration-damping support rod suitable for offshore floating structures according to claim 4, characterized in that: The force-applying fixing sleeve (12) comprises a fixing sleeve (1201) sleeved on the steel wire rope (5) and a fixing cover (1202) located at the end of the fixing sleeve and covering the third butterfly spring, the end of the third butterfly spring (11) abuts against the end of the fixing sleeve (1201), and the force-applying threaded cap (13) presses the other end of the fixing sleeve (1202); a rubber sleeve (21) is sleeved on the outer side of the fixing sleeve (1202), one end of the rubber sleeve (21) abuts against the end surface of the fixing cover (1201), and the other end of the rubber sleeve (21) abuts against the vibration-damping gasket (19) of the housing assembly.

9. The multi-directional vibration-damping support rod suitable for offshore floating structures according to claim 1, characterized in that: The U-shaped latch of the left support assembly is hinged to the end connection piece (2) of the left support assembly via a first hinge shaft (22), the end connection piece (2) of the left support assembly is hinged to the floating structure via a left hinge shaft (1), and the left hinge shaft (1) and the first hinge shaft (22) are perpendicular to each other; the U-shaped latch of the right support assembly is hinged to the end connection piece (2) of the right support assembly via a second hinge shaft (24), the end connection piece (2) of the right support assembly is hinged to the floating structure via a right hinge shaft (23), and the right hinge shaft (23) and the second hinge shaft (24) are perpendicular to each other.

10. The multi-directional vibration-damping support rod suitable for offshore floating structures according to claim 1, characterized in that: The loss factors of the first butterfly spring (7), the second butterfly spring (9) and the third butterfly spring (11) are greater than 0.06.

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