Multi-mechanism collaborative seismic mitigation and isolation support

Abstract

The invention relates to the technical field of shock absorption, in particular to a multi-mechanism collaborative shock absorption and isolation support which comprises an upper cover and an inerter system, the lower end of the upper cover is connected with a first box through an elastic support, the inerter system vertically penetrates through the upper cover, a first eddy current damping system is arranged at the upper end of the inerter system, and the lower end of the inerter system is connected with the first box. A second box body is arranged in the first box body, a double-layer nonlinear energy trap system is arranged in the second box body, the upper wall of the first box body is connected with the upper wall of the second box body through an elastic plug connector, and the lower wall of the first box body is connected with the lower wall of the second box body through an elastic plug connector; according to the shock absorption and isolation support, various shock absorption systems are matched with one another, so that the whole shock absorption and isolation support can effectively work under various shock frequencies and strengths, an excellent shock absorption and isolation effect can be achieved in a complex earthquake environment, and the anti-seismic performance of a building is remarkably improved.

Description

Technical Field

[0001] The present invention relates to the field of shock absorption technology, and in particular to a multi-mechanism coordinated shock absorption and isolation bearing suitable for high-rise buildings, bridge projects, large-span structures, transformer substations and other important facilities. Background Art

[0002] When designing and applying seismic isolation bearings, it is necessary to consider their performance under earthquake action. Traditional seismic isolation bearings usually include rubber bearings, friction pendulum bearings, etc. These bearings use different mechanisms to reduce the impact of seismic energy on the superstructure. For example, rubber bearings use their high elastic modulus and deformability to absorb and disperse seismic energy, thereby extending the natural period of the structure and reducing the effect of seismic forces. Friction pendulum bearings achieve simple pendulum motion through the movement of the spherical sliding surface and use the friction coefficient to control damping, thereby achieving seismic isolation effect.

[0003] However, traditional seismic isolation bearings have certain limitations when dealing with complex seismic environments. Although rubber bearings can effectively absorb seismic energy, their vertical bearing capacity is relatively low when facing large vibration frequencies or complex seismic environments, especially in long-span bridges or high-rise buildings, and they often cannot meet the stringent bearing requirements. In addition, rubber materials are easily affected by temperature, humidity and environmental factors during long-term use, resulting in performance degradation, such as hardening or aging, which in turn reduces the seismic performance of the bearings.

[0004] While friction pendulum bearings can provide good shock absorption under horizontal earthquakes, their residual displacement is large, which may affect the long-term stability of the building structure. Especially after a strong earthquake, the friction surface of the friction pendulum bearing may produce a large displacement, affecting the recovery of the structure. In addition, the damping performance of the friction pendulum bearing is often greatly affected by changes in ambient temperature, and performance instability may occur in low or high temperature environments. This is a problem that cannot be ignored for buildings in special earthquake environments.

[0005] In addition, although traditional lead rubber bearings can provide good seismic isolation effects in ordinary earthquake environments, under high load conditions, the bearings may experience permanent deformation, affecting their subsequent seismic resistance, especially under long-term high loads, their durability will be greatly affected. Therefore, traditional bearings cannot always maintain good performance in extreme climates, humid environments, and high-pressure environments.

[0006] In order to address the limitations of these traditional seismic isolation bearings, new seismic isolation bearings have gradually introduced a variety of innovative technologies. For example, segmented intelligent seismic isolation bearings that combine magnetorheological elastomers and shear-thickening magnetorheological plastics can adjust their stiffness and damping characteristics according to different earthquake intensities, thereby providing a more flexible seismic solution. However, although these new designs can cope with vibrations of different seismic frequencies, there is still a risk of uneven performance when facing complex seismic environments, especially in the case of three-dimensional earthquakes, where the synergy between systems may be poor, resulting in limited overall shock absorption effects.

[0007] Although the application of the new SMA first eddy current damping system and viscous dampers provides additional energy dissipation pathways for seismic isolation bearings and improves seismic performance, these systems usually involve more complex structural designs and higher costs, which increase the design difficulty and manufacturing costs of the bearings, and in some cases, may not achieve sufficient shock absorption effects under extreme earthquake conditions.

[0008] Therefore, traditional seismic isolation bearings have shown certain limitations when dealing with multi-dimensional earthquakes, complex vibrations and harsh environments, especially in terms of bearing capacity, durability, adaptability and vibration response accuracy. To this end, it is necessary to develop a new type of seismic isolation bearing that can comprehensively solve these problems. By combining multiple shock-absorbing mechanisms, it can not only improve the shock-absorbing performance, but also enhance the adaptability and durability of the bearing to meet the seismic requirements of buildings in complex seismic environments. Summary of the invention

[0009] In view of the shortcomings of the prior art, the present invention proposes a multi-mechanism coordinated seismic isolation bearing, which, through the coordination of multiple mechanisms, can simultaneously cope with earthquakes of different intensities in horizontal, vertical and other complex directions, thereby better reducing the vibration of the building structure and significantly improving the seismic performance of the building.

[0010] To achieve the above object, the present invention adopts the following technical solutions:

[0011] The present invention proposes a multi-mechanism coordinated seismic isolation bearing, including an upper cover and an inertia capacity system, wherein the lower end of the upper cover is connected to a first box body through an elastic support, the inertia capacity system passes through the upper cover from top to bottom, and a first eddy current damping system is arranged at the upper end, and the lower end is connected to the first box body, a second box body is arranged inside the first box body, a double-layer nonlinear energy well system is arranged inside the second box body, and the upper wall of the first box body and the upper wall of the second box body, as well as the lower wall of the first box body and the lower wall of the second box body are connected by elastic connectors.

[0012] Specifically, the inertia volume system includes a connecting column, which passes through the upper cover from top to bottom, the upper end of which is fixedly connected to a flywheel, and the lower end is fixedly connected to a face gear, the face gear is meshed with a rack, and the rack is fixedly arranged at the upper end of the first box body, and the flywheel is filled with viscous fluid.

[0013] Specifically, the first eddy current damping system includes a metal disk, which is arranged at the upper end of the inertial capacitance system. A first permanent magnet is arranged on the periphery of the metal disk, and the first permanent magnet is arranged at the upper end of the upper cover.

[0014] Specifically, a second eddy current damping system is also arranged inside the first box body, and the second eddy current damping system includes a second permanent magnet and a shape memory alloy. The second permanent magnet is arranged on the outer wall of the second box body, and the shape memory alloy is arranged between the upper wall of the first box body and the upper wall of the second box body and / or between the lower wall of the first box body and the lower wall of the second box body.

[0015] Specifically, a resistor sheet is wrapped around the shape memory alloy.

[0016] Specifically, the double-layer nonlinear energy trap system includes a third box, the outside of the third box is connected to the second box by an elastic member, a third permanent magnet and a fourth permanent magnet are arranged in the third box, the third permanent magnet is located on the left side of the fourth permanent magnet, a fifth permanent magnet and a sixth permanent magnet are arranged between the third permanent magnet and the fourth permanent magnet, the fifth permanent magnet and the sixth permanent magnet have opposite magnetic poles and are attracted to each other, the fifth permanent magnet is located between the third permanent magnet and the sixth permanent magnet, the attraction point of the fifth permanent magnet and the sixth permanent magnet is respectively connected to the upper wall and the lower wall of the third box by an elastic member, the third permanent magnet and the fifth permanent magnet have the same magnetic pole, and the fourth permanent magnet and the sixth permanent magnet have the same magnetic pole.

[0017] Specifically, a damper is arranged between the upper wall of the second box body and the upper wall of the third box body and / or between the lower wall of the second box body and the lower wall of the third box body.

[0018] Specifically, the damper is a viscous damper or a viscoelastic damper.

[0019] Specifically, non-magnetic steel is provided on the inner surface of the side wall of the first box body.

[0020] Specifically, the elastic connector includes a first concave block and a second concave block, the first concave block is arranged on the first box body, the second concave block is arranged on the second box body, the second concave block is opposite to the notch of the first concave block, and the second concave block is embedded in the groove of the first concave block, and the first concave block and the second concave block are also connected by an elastic member.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) The seismic isolation bearing of the present invention cooperates with each other through a double-layer nonlinear energy sink system, an inertia system, a first eddy current damping system and a second eddy current damping system, so that the entire seismic isolation bearing can work effectively under a variety of vibration frequencies and intensities. Compared with the traditional single shock absorption mechanism, the present invention can respond to earthquakes of different intensities more comprehensively and accurately, whether it is a small earthquake or a medium or large earthquake, it can better reduce the vibration of the building structure through the collaboration of multiple systems. In particular, the present invention takes into account the impact of three-dimensional earthquakes and can simultaneously cope with vibrations in horizontal, vertical and other complex directions, while traditional seismic isolation bearings are mostly limited to dealing with horizontal earthquakes. Therefore, the present invention can exert superior seismic isolation effects in more complex seismic environments, significantly improve the seismic resistance of buildings, and have stronger adaptability under multi-dimensional earthquakes, providing a more flexible and comprehensive shock absorption solution for the field of seismic isolation.

[0023] (2) Traditional seismic isolation bearings are generally simple in design or made of a single material. During long-term use, seismic isolation bearings are affected by environmental factors such as temperature, humidity, chemicals, and ultraviolet rays, and are prone to aging, corrosion, damage, and other problems, resulting in a gradual reduction in their performance. Especially in some harsh environments, such as marine climates and places with extreme temperature differences, the durability and adaptability of traditional seismic isolation bearings cannot meet the requirements of long-term use. In contrast, the present invention combines a nonlinear seismic isolation system, an inertial capacity system, a metal disk eddy current damping system, and an SMA eddy current damping system. These systems can complement each other and have strong weather resistance, anti-aging, and anti-corrosion. While improving the adaptability of seismic isolation bearings to different types of vibrations, they can better resist the influence of the environment, thereby maintaining good performance in long-term use. Whether in extreme climatic conditions, humid environments, areas with strong vibrations, or in special environments such as high temperature and high pressure, the present invention can maintain good working performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the overall structure of the seismic isolation support of the present invention;

[0025] Figure 2 It is a schematic structural diagram of the elastic connector of the present invention;

[0026] Figure 3 It is a schematic diagram of the structure of a double-layer nonlinear energy sink system;

[0027] Figure numerals: 1. upper cover; 2. inertia system; 201. flywheel; 202. connecting column; 203. face gear; 204. rack; 3. first eddy current damping system; 301. metal disk; 302. first permanent magnet; 4. elastic support; 5. first housing; 6. elastic connector; 601. first concave block; 602. second concave block; 7. double-layer nonlinear energy well system; 701. third housing; 702. third permanent magnet; 703. fifth permanent magnet; 704. sixth permanent magnet; 705. fourth permanent magnet; 706. damper; 8. second eddy current damping system; 801. second permanent magnet; 802. shape memory alloy; 9. non-magnetic steel; 10. second housing. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] Example

[0030] refer to Figure 1 The present embodiment proposes a multi-mechanism coordinated seismic isolation bearing, including an upper cover 1 and an inertia capacity system 2. The lower end of the upper cover 1 is connected to the first box body 5 through an elastic support 4. The inertia capacity system 2 runs through the upper cover 1 from top to bottom, and a first eddy current damping system 3 is arranged at the upper end, and the lower end is connected to the first box body 5. A second box body 10 is arranged inside the first box body 5, and a double-layer nonlinear energy well system 7 is arranged inside the second box body 10. The upper wall of the first box body 5 and the upper wall of the second box body 10 and the lower wall of the first box body 5 and the lower wall of the second box body 10 are connected by elastic connectors 6.

[0031] In this embodiment, when horizontal vibration occurs, the relative displacement between the first box body 5 and the upper cover 1 is converted into the rotation amount of the inertial capacitance system 2, and the energy generated by the vibration is stored and consumed. At the same time, during the rotation of the inertial capacitance system 2, the first eddy current damping system 3 will be driven to generate annular eddy currents to consume the stored energy of the inertial capacitance system 2. Since the eddy current distribution will also change with the rotation speed of the inertial capacitance system 2, a reverse magnetic field will be generated to form resistance, which will further consume the stored energy of the inertial capacitance system 2, thereby reducing the relative displacement between the first box body 5 and the upper cover 1. In addition, the elastic support 4 also plays a role in shock absorption and isolation. After the vibration ends, the first box body 5 and the upper cover 1 are reset under the action of the elastic support 4; when vertical vibration occurs, the double-layer nonlinear energy well system 7 consumes energy. The setting of the elastic connector 6 as the double-layer nonlinear energy well system 7 can play a guiding role, guiding the double-layer nonlinear energy well system 7 to move in the vertical direction. After the vibration ends, the double-layer nonlinear energy well system 7 is reset under the action of the elastic connector 6.

[0032] Specifically, the inertia system 2 includes a connecting column 202, which passes through the upper cover 1 from top to bottom and can rotate relative to the upper cover 1. The upper end of the connecting column 202 is fixedly connected to the flywheel 201, and the lower end is fixedly connected to the face gear 203. The face gear 203 is meshed with the rack 204, and the rack 204 is fixedly arranged at the upper end of the first box body 5. The flywheel 201 is filled with viscous fluid; the first eddy current damping system 3 is a metal disk 301 eddy current damping system, including a metal disk 301, which is sleeved on the connecting column 202 and fixedly connected to the lower end of the flywheel 201. The periphery of the metal disk 301 is provided with a first permanent magnet 302, which is an annular permanent magnet. The first permanent magnet 302 is arranged at the upper end of the upper cover 1, and a groove can be opened at the upper end of the upper cover 1 to arrange the first permanent magnet 302 on the side wall of the groove.

[0033] In this embodiment, when horizontal vibration occurs, a relative displacement occurs between the first box body 5 and the upper cover 1. Since the rack 204 and the face gear 203 are meshed, the moving rack 204 drives the face gear 203 to rotate, thereby driving the connecting column 202 to rotate, and converting the relative displacement in the horizontal direction into the rotation of the connecting column 202. The connecting column 202 drives the flywheel 201 and the metal disk 301 to rotate, so that the horizontal displacement of the lower box body is converted into the rotation amount of the inertia system 2. The flywheel 201 drives the viscous liquid inside it to rotate. The viscous liquid will hinder the rotation and generate a damping force to convert the vibration energy into heat energy, thereby further reducing the transmission of vibration, which will inevitably gradually reduce the relative displacement between the upper cover 1 and the lower box body. Therefore, in this embodiment, the inertia system 2 is equivalent to The energy generated by the earthquake is stored and consumed, thereby effectively decomposing the earthquake energy; the eddy current damping system of the metal disk 301 includes an annular permanent magnet and a metal disk 301, and the annular permanent magnet is sleeved on the outer periphery of the metal disk 301. When the metal disk 301 rotates with the connecting column 202, annular eddy currents will be induced on its surface. The eddy current distribution in the metal disk 301 gradually changes with the speed, and these eddy currents will generate a reverse magnetic field. The change in the magnetic field intensity will cause the equivalent eddy current damping coefficient to be nonlinearly negatively correlated with the permanent magnet movement speed, forming resistance, hindering the rotation of the metal disk 301, and converting the mechanical energy of the metal disk 301 into heat energy, further consuming the energy stored in the inertia system 2, so that the relative displacement of the upper cover 1 and the first box body 5 is quickly reduced to stop.

[0034] Specifically, refer to Figure 1 and Figure 3The double-layer nonlinear energy trap system 7 includes an outer structure and an inner structure, wherein the outer structure includes a third box 701 and an elastic member arranged between the outside of the third box 701 and the inner wall of the second box 10, and the inner structure includes a third permanent magnet 702 and a fourth permanent magnet 705 arranged in the third box 701, the third permanent magnet 702 is located on the left side of the fourth permanent magnet 705, and a fifth permanent magnet 703 and a sixth permanent magnet 704 are arranged between the third permanent magnet 702 and the fourth permanent magnet 705, the fifth permanent magnet 703 and the sixth permanent magnet 704 are opposite magnetic poles and the two are attracted under the action of magnetic force, and the fifth permanent magnet 703 is located between the third permanent magnet 702 and the sixth permanent magnet 704. 4, the attraction point of the fifth permanent magnet 703 and the sixth permanent magnet 704 is respectively connected to the upper wall and the lower wall of the third box 701 through an elastic member, the third permanent magnet 702 has the same magnetic pole as the fifth permanent magnet 703, and the fourth permanent magnet 705 has the same magnetic pole as the sixth permanent magnet 704; a second eddy current damping system 8 is also arranged inside the first box 5, and the second eddy current damping system 8 includes a second permanent magnet 801 and a shape memory alloy 802, the second permanent magnet 801 is arranged on the outer wall of the second box 10, and the shape memory alloy 802 is arranged between the upper wall of the first box 5 and the upper wall of the second box 10 or between the lower wall of the first box 5 and the lower wall of the second box 10.

[0035] In this embodiment, when vibration occurs in the vertical direction, the inner and outer layers are combined to form a double-layer nonlinear energy well system 7, which constitutes nonlinearity and consumes energy through damping. The inner layer structure of the double-layer nonlinear energy well system 7 can generate a force according to the vibration change, pushing the elastic member of the outer layer structure to absorb energy. Especially when the vibration is strong, the double-layer nonlinear energy well system 7 can effectively distribute and release seismic energy, thereby reducing the impact of the vibration on the upper structure. At the same time, during the movement of the double-layer nonlinear energy well system 7, the shape memory alloy 802 can move and deform in the vertical direction through its shape memory effect, and cut the magnetic flux generated by the second permanent magnet 801 through telescopic transformation to generate current. A resistance layer can also be attached to the outside of the shape memory alloy 802 to increase the resistance, generate heat and consume energy, provide additional damping effect for the shape memory alloy 802, and reduce vibration. When the vibration stops, the vibration isolation support is reset under the action of the elastic connector 6 and the elastic member at the suction point of the fifth permanent magnet 703 and the sixth permanent magnet 704, and the shape memory alloy 802 will also return to its original state through the shape memory effect.

[0036] Specifically, a damper 706 is provided between the upper wall of the second box 10 and the upper wall of the third box 701 and / or between the lower wall of the second box 10 and the lower wall of the third box 701. The inner structure of the double-layer nonlinear energy sink system 7 can generate a force according to the vibration change, which can push the elastic member of the outer structure to absorb energy and also push the damper 706 to absorb energy, thereby further improving the energy consumption effect of the double-layer nonlinear energy sink system 7.

[0037] Specifically, refer to Figure 1 and Figure 2 The elastic connector 6 includes a first concave block 601 and a second concave block 602. The first concave block 601 is arranged on the first box body 5, and the second concave block 602 is arranged on the second box body 10. The second concave block 602 is opposite to the notch of the first concave block 601, and the second concave block 602 is embedded in the groove of the first concave block 601. The first concave block 601 and the second concave block 602 are also connected by an elastic member.

[0038] In this embodiment, the grooves of the two concave blocks are relatively plugged in, and the groove bottoms of the two concave blocks are connected by elastic parts, which can play a guiding and resetting role and save space. It can ensure that the double-layer nonlinear energy well system 7 is in a longitudinal straight line when vibrating. This connection method can ensure that the upper and lower structures work together to avoid vibration transmission or structural damage due to loose connection.

[0039] Specifically, the inner surface of the side wall of the first box body 5 is provided with non-magnetic steel 9 to provide structural support, thereby increasing the strength of the side wall of the first box body 5 without interfering with the magnetic force between the second eddy current damping system 8 and avoiding magnetic leakage.

[0040] In the above embodiments, the elastic member is a resettable spring, and may also be other elastomers that meet the requirements. The elastic support 4 is made of rubber. The position distribution and quantity of the elastic member between the second box body 10 and the third box body 701, the elastic member in the third box body 701, the shape memory alloy 802, and the elastic connector 6, and the plug-in length of the two concave blocks of the elastic connector 6 can all be determined according to design requirements. The metal plate 301 is made of copper, nickel, aluminum, etc.

[0041] The specific embodiments of the present invention enable those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention.

[0042] It should be understood that the present invention is not limited to what has been described above and that various modifications and changes may be made without departing from its scope. The scope of the present invention is limited only by the appended claims.

Claims

1. A multi-mechanism coordinated seismic isolation bearing, characterized in that: The invention comprises an upper cover (1) and an inertia capacity system (2), wherein the lower end of the upper cover (1) is connected to a first box (5) via an elastic support (4), the inertia capacity system (2) passes through the upper cover (1) from top to bottom, and a first eddy current damping system (3) is arranged at the upper end, and the lower end is connected to the first box (5), a second box (10) is arranged inside the first box (5), a double-layer nonlinear energy sink system (7) is arranged inside the second box (10), and the upper wall of the first box (5) and the upper wall of the second box (10) and the lower wall of the first box (5) and the lower wall of the second box (10) are connected via elastic connectors (6).

2. The multi-mechanism coordinated seismic isolation bearing according to claim 1 is characterized in that: The inertia system (2) comprises a connecting column (202), the connecting column (202) passes through the upper cover (1) from top to bottom, the upper end of which is fixedly connected to a flywheel (201), and the lower end of which is fixedly connected to a face gear (203), the face gear (203) is meshed with a rack (204), the rack (204) is fixedly arranged at the upper end of the first housing (5), and the flywheel (201) is filled with a viscous fluid.

3. The multi-mechanism coordinated seismic isolation bearing according to claim 1 is characterized in that: The first eddy current damping system (3) comprises a metal disk (301), the metal disk (301) being arranged at the upper end of the inertial capacitance system (2), a first permanent magnet (302) being arranged on the periphery of the metal disk (301), and the first permanent magnet (302) being arranged at the upper end of the upper cover (1).

4. The multi-mechanism coordinated seismic isolation bearing according to claim 1 is characterized in that: A second eddy current damping system (8) is also arranged inside the first box (5), and the second eddy current damping system (8) comprises a second permanent magnet (801) and a shape memory alloy (802), wherein the second permanent magnet (801) is arranged on the outer wall of the second box (10), and the shape memory alloy (802) is arranged between the upper wall of the first box (5) and the upper wall of the second box (10) and / or between the lower wall of the first box (5) and the lower wall of the second box (10).

5. The multi-mechanism coordinated seismic isolation bearing according to claim 4 is characterized in that: The shape memory alloy (802) is surrounded by a resistor sheet.

6. The multi-mechanism coordinated seismic isolation bearing according to claim 1 is characterized in that: The double-layer nonlinear energy trap system (7) comprises a third box (701), the outside of the third box (701) is connected to the second box (10) via an elastic member, a third permanent magnet (702) and a fourth permanent magnet (705) are arranged in the third box (701), the third permanent magnet (702) is located on the left side of the fourth permanent magnet (705), a fifth permanent magnet (703) and a sixth permanent magnet (704) are arranged between the third permanent magnet (702) and the fourth permanent magnet (705), and the third permanent magnet (702) and the fourth permanent magnet (705) are arranged on the left side of the third permanent magnet (702) and the fourth permanent magnet (705). The fifth permanent magnet (703) and the sixth permanent magnet (704) have opposite magnetic poles and are attracted to each other. The fifth permanent magnet (703) is located between the third permanent magnet (702) and the sixth permanent magnet (704). The attraction point between the fifth permanent magnet (703) and the sixth permanent magnet (704) is respectively connected to the upper wall and the lower wall of the third box (701) through an elastic member. The third permanent magnet (702) and the fifth permanent magnet (703) have the same magnetic poles, and the fourth permanent magnet (705) and the sixth permanent magnet (704) have the same magnetic poles.

7. The multi-mechanism coordinated seismic isolation bearing according to claim 6 is characterized in that: A damper (706) is provided between the upper wall of the second box body (10) and the upper wall of the third box body (701) and / or between the lower wall of the second box body (10) and the lower wall of the third box body (701).

8. The multi-mechanism coordinated seismic isolation bearing according to claim 7 is characterized in that: The damper (706) is a viscous damper (706) or a viscoelastic damper (706).

9. The multi-mechanism coordinated seismic isolation bearing according to claim 1 is characterized in that: The inner surface of the side wall of the first box body (5) is provided with non-magnetic steel (9).

10. The multi-mechanism coordinated seismic isolation bearing according to claim 1 is characterized in that: The elastic plug-in connector (6) comprises a first concave block (601) and a second concave block (602); the first concave block (601) is arranged on the first box body (5); the second concave block (602) is arranged on the second box body (10); the second concave block (602) is opposite to the notch of the first concave block (601), and the second concave block (602) is embedded in the groove of the first concave block (601); the first concave block (601) and the second concave block (602) are also connected via an elastic member.

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