A wind turbine tower and foundation connector

Abstract

The present invention provides a wind turbine tower and foundation connector, comprising an upper connector and a lower connector. The upper connector comprises an upper body, the upper body comprising an abutment section and an insertion section, the radial dimension of the abutment section being larger than the radial dimension of the insertion section, and the outer wall of the insertion section further comprising a plurality of spaced centering blocks. The lower connector comprises a lower body, the lower body comprising an insertion cavity extending along its axial direction, the insertion section being adapted to be inserted into the insertion cavity and fixedly connected to the sidewall of the insertion cavity to securely connect the upper and lower connectors. The sidewall of the insertion cavity further comprises a plurality of centering slots for inserting the centering blocks, the number and shape of the centering slots matching the number and shape of the centering blocks. The wind turbine tower and foundation connector are used to securely connect the wind turbine tower and foundation. Compared with the prior art, the present invention can reduce the difficulty of connector centering and improve installation efficiency, thereby reducing wind turbine installation costs.

Description

Technical Field

[0001] The present invention relates to the technical field of wind power generation, and in particular to a wind turbine tower and foundation connector. Background Art

[0002] As a key component of my country's dual carbon goals, offshore wind turbines have seen rapid growth in recent years. Offshore wind turbines are categorized as floating and fixed. Compared to fixed wind turbines, floating wind turbines offer a cost advantage.

[0003] Currently, floating wind turbines are typically hoisted, with the tower, chassis, blades, and other components connected to the foundation via connecting devices. Due to the effects of wind, waves, and currents, centering the connecting devices during the connection process is challenging. Furthermore, manual connection is often required after centering, resulting in low installation efficiency. This significantly increases the proportion of wind turbine installation costs in the overall construction cost. Summary of the Invention

[0004] The purpose of the present invention is to provide a wind turbine tower and base connector to address the deficiencies in the above-mentioned prior art, which can reduce the difficulty of centering the connector and improve installation efficiency, thereby reducing the proportion of wind turbine installation costs in the wind turbine cost.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A wind turbine tower and foundation connector, comprising:

[0007] An upper connecting member, comprising an upper main body, the upper main body comprising an abutting section and an inserting section, the radial dimension of the abutting section being larger than the radial dimension of the inserting section, and the outer wall of the inserting section further comprising a plurality of centering blocks arranged at intervals;

[0008] A lower connecting member, the lower connecting member comprising a lower main body, the lower main body having an inserting cavity opened along its axial direction, the inserting section being adapted to be inserted into the inserting cavity and fixedly connected to the side wall of the inserting cavity to fixedly connect the upper connecting member to the lower connecting member, the side wall of the inserting cavity further having a plurality of centering grooves for inserting the centering blocks, the number and shape of the centering grooves matching the number and shape of the centering blocks;

[0009] A plurality of clamping blocks, wherein the upper body has a sliding cavity opened along its axial direction, and the plurality of clamping blocks are radially slidably arranged on the side wall of the sliding cavity of the plug-in section, and the side wall of the plug-in cavity has a plurality of clamping holes for the clamping blocks to be clamped into, and one end of the clamping block close to the clamping hole has an insertion surface;

[0010] A sliding core, the sliding core being slidably disposed in the sliding cavity, the sliding core having a plurality of grooves corresponding to the clamping blocks, the grooves having a driving surface therein, the driving surface being capable of driving the clamping blocks to slide, the bottom surface of the sliding core having a deceleration hole opened along its axis, the side wall of the deceleration hole having a first deceleration structure, and the bottom wall of the sliding cavity having a straight hole arranged corresponding to the deceleration hole;

[0011] A deceleration plate, the deceleration plate is rotatably arranged in the plug-in cavity, the deceleration plate has a deceleration rod coaxially arranged therewith, the deceleration rod has a second deceleration structure at one end away from the deceleration plate, the second deceleration structure is suitable for cooperating with the first deceleration structure to make the upper body and the sliding core slide relative to each other during the process of inserting the plug-in section into the plug-in cavity, so as to ensure that the insertion section can be inserted into place and the clamping block can be smoothly clamped into the clamping hole.

[0012] Preferably, the centering block and the centering groove are in the shape of an inverted isosceles trapezoid.

[0013] Preferably, the outer wall of the plug-in section has two symmetrically arranged centering blocks, and the inner side wall of the plug-in cavity has two symmetrically arranged centering grooves.

[0014] Preferably, the end of the plug-in section away from the abutting section is in the shape of an inverted truncated cone.

[0015] Preferably, the clamping block has a rolling roller at one end close to the sliding core, and the clamping block contacts the driving surface through the roller.

[0016] Preferably, the insertion surface and the driving surface are arc-shaped surfaces or inclined surfaces respectively.

[0017] Preferably, one of the first deceleration structure and the second deceleration structure is an arc-shaped protrusion, and the other is an arc-shaped groove.

[0018] Preferably, it also includes a positioning plate, which is rotatably arranged at the bottom end of the plug-in cavity and fixedly connected to the speed reduction plate. The positioning plate has a positioning cam, and the bottom end of the plug-in cavity has a stopping tooth. The stopping tooth is suitable for cooperating with the positioning cam to position the speed reduction plate.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] (1) Before the connector provided by the present invention is connected, the upper connector and the lower connector are first installed on the wind turbine tower and the foundation, and then the wind turbine tower is hoisted for installation. When the wind turbine tower is connected to the foundation, the front end of the plug-in section of the upper connector first enters the plug-in cavity on the lower connector, realizing the first alignment of the upper connector and the lower connector. Then, as the plug-in section of the upper connector continues to enter the plug-in cavity of the lower connector, the centering block on the outer wall of the plug-in section of the upper connector is inserted into the centering groove on the inner wall of the plug-in cavity of the lower connector, realizing the second alignment of the upper connector and the lower connector. Therefore, the connector provided by the present invention ensures the smooth alignment of the wind turbine tower and the foundation through two consecutive alignments, indirectly reduces the influence of wind and wave flow on the alignment of the wind turbine tower and the foundation, reduces the difficulty of the wind turbine tower and foundation alignment operation, and can shorten the construction time and improve the construction efficiency.

[0021] (2) The connector provided by the present invention uses the deadweight of the wind turbine tower and the sliding core as the connection power, and completes the connection and fixation of the upper connecting part and the lower connecting part through the differential movement of the upper connecting part and the sliding core. This not only solves the problem of the large amount of construction equipment and complicated installation steps required by existing large-scale connecting devices, but also saves energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the specific embodiments of the present invention, the following briefly introduces the drawings required for use in the specific embodiments. It should be noted that in all the drawings, the various elements or parts are not necessarily drawn according to the actual scale.

[0023] Figure 1 An exploded view of the overall structure of the wind turbine tower and the base connector according to an embodiment of the present invention;

[0024] Figure 2 This is a cross-sectional view of the overall structure of the upper connecting piece of the wind turbine tower and the base connector according to an embodiment of the present invention;

[0025] Figure 3 This is a cross-sectional view of the overall structure of the wind turbine tower and the lower connecting piece of the base connector according to an embodiment of the present invention;

[0026] Figure 4 A cross-sectional view of the overall structure of the wind turbine tower and the sliding core of the basic connector according to an embodiment of the present invention;

[0027] Figure 5 This is a cross-sectional view of the overall structure of the wind turbine tower and the speed reduction disc of the basic connector according to an embodiment of the present invention;

[0028] Figure 6 A cross-sectional view of the overall structure of the wind turbine tower and the upper connecting member and the lower connecting member of the base connector when fixedly connected in an embodiment of the present invention;

[0029] Figure 7 for Figure 6 AA section view in;

[0030] Figure 8 Schematic diagram of the cooperation between the first deceleration structure and the second deceleration structure of the wind turbine tower and the basic connector in an embodiment of the present invention;

[0031] Figure 9 Schematic diagram of the process of connecting the upper connecting piece and the lower connecting piece of the wind turbine tower and the base connector according to an embodiment of the present invention;

[0032] Figure 10 This is another schematic diagram of the process of connecting the upper connecting piece and the lower connecting piece of the wind turbine tower and the basic connector in an embodiment of the present invention.

[0033] In the picture:

[0034] 1. Upper connecting piece; 11. Abutting section; 12. Inserting section; 13. Centering block; 14. Sliding cavity; 15. Straight hole; 2. Lower connecting piece; 21. Inserting cavity; 22. Centering groove; 23. Clamping hole; 24. Stop tooth; 3. Clamping block; 31. Inserting surface; 32. Roller; 4. Sliding core; 41. Groove; 42. Driving surface; 43. Speed reduction hole; 44. First speed reduction structure; 5. Speed reduction disc; 51. Speed reduction rod; 52. Second speed reduction structure; 53. Threaded connection hole; 6. Positioning disc; 61. Positioning cam; 62. Threaded connection part. DETAILED DESCRIPTION

[0035] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0036] In the description of the present invention, it should be noted that the terms "upper," "lower," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate the description of the present invention and simplify the description. They do not indicate or imply that the systems or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the use of terms such as "first" and "second" to define components is solely for the purpose of distinguishing those components. Unless otherwise stated, these terms have no special meanings and should not be construed as indicating or implying relative importance.

[0037] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0038] Currently, floating wind turbines typically use a hoisting method to connect components such as the tower, chassis, and blades to the foundation via a connecting device. Due to the effects of wind, waves, and currents, centering the connecting device during the connection process is difficult. Furthermore, manual connection is required after centering the connecting device, resulting in low installation efficiency. This can increase the proportion of wind turbine installation costs to the total cost of the wind turbine. Therefore, the present invention provides a wind turbine tower and foundation connector that reduces the difficulty of connector centering and improves installation efficiency, thereby reducing the proportion of wind turbine installation costs to the total cost of the wind turbine.

[0039] Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. Rather, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0040] like Figure 1-Figure 3 As shown, an embodiment of the present invention provides a wind turbine tower and foundation connector, including:

[0041] The upper connecting member 1 includes an upper body, which includes an abutting section 11 and an inserting section 12. The radial dimension of the abutting section 11 is larger than the radial dimension of the inserting section 12. The inserting section 12 also has a plurality of centering blocks 13 arranged at intervals on the outer wall.

[0042] The lower connecting member 2 includes a lower main body, which has an inserting cavity 21 opened along its axial direction. The inserting section 12 is suitable for being inserted into the inserting cavity 21 and fixedly connected to the side wall of the inserting cavity 21 to fixedly connect the upper connecting member 1 and the lower connecting member 2. The side wall of the inserting cavity 21 also has a plurality of centering grooves 22 for inserting the centering blocks 13. The number and shape of the centering grooves 22 match the number and shape of the centering blocks 13.

[0043] like Figure 9As shown, before the connector provided by the embodiment of the present invention is connected, the upper connector 1 and the lower connector 2 are first installed on the wind turbine tower and the foundation, and then the wind turbine tower is hoisted for installation. When the wind turbine tower is connected to the foundation, the upper connector 1 falls together with the wind turbine tower, and the front end of the plug-in section 12 on it first enters the plug-in cavity 21 on the lower connector 2, achieving the first alignment of the upper connector 1 and the lower connector 2. Subsequently, as the plug-in section 12 of the upper connector 1 continues to enter the plug-in cavity 21 of the lower connector 2, the centering block 13 on the outer wall of the plug-in section 12 of the upper connector 1 will be inserted into the centering groove 22 on the inner wall of the plug-in cavity 21 of the lower connector 2, achieving the second alignment of the upper connector 1 and the lower connector 2. Therefore, the connector provided by the present invention ensures the smooth alignment of the wind turbine tower and the foundation through two consecutive alignments, indirectly weakens the impact of wind and wave flow on the alignment of the wind turbine tower and the foundation, reduces the difficulty of the alignment operation of the wind turbine tower and the foundation, thereby shortening the construction time and improving construction efficiency.

[0044] Furthermore, the centering block 13 and the centering slot 22 are in the shape of an inverted isosceles trapezoid. In this embodiment, the centering block 13 and the centering slot 22 are arranged in the shape of an inverted isosceles trapezoid, which can facilitate the insertion of the centering block 13 into the centering slot 22, thereby ensuring smooth centering of the wind turbine tower and the foundation.

[0045] Of course, in some other embodiments, the centering block 13 and the centering groove 22 may also adopt other shapes such as a rectangle, an isosceles triangle, etc.

[0046] It is understandable that the number of the centering blocks 13 and the centering slots 22 can be set accordingly according to actual needs, and this embodiment does not impose any limitation on this.

[0047] Preferably, in this embodiment, the outer wall of the plug-in section 12 has two symmetrically arranged centering blocks 13 , and the inner wall of the plug-in cavity 21 has two symmetrically arranged centering grooves 22 .

[0048] Furthermore, the end of the plug section 12 away from the abutting section 11 is in the shape of an inverted truncated cone. In this embodiment, by setting the end of the plug section 12 away from the abutting section 11 in the shape of an inverted truncated cone, the plug section 12 can be easily inserted into the plug cavity 21.

[0049] like Figure 4-Figure 7 As shown, in another embodiment of the present invention, it also includes:

[0050] A plurality of clamping blocks 3 are provided. The upper body has a sliding cavity 14 opened along its axial direction. The plurality of clamping blocks 3 are radially slidably arranged on the side wall of the sliding cavity 14 of the plug-in section 12. The side wall of the plug-in cavity 21 has a plurality of clamping holes 23 for the clamping blocks 3 to be clamped in. The end of the clamping block 3 adjacent to the clamping hole 23 has an insertion surface 31.

[0051] The sliding core 4 is slidably disposed in the sliding cavity 14. The sliding core 4 has a plurality of grooves 41 corresponding to the clamping blocks 3. The grooves 41 have driving surfaces 42 therein. The driving surfaces 42 can drive the clamping blocks 3 to slide. The bottom surface of the sliding core 4 has a deceleration hole 43 opened along its axis. The side wall of the deceleration hole 43 has a first deceleration structure 44. The bottom wall of the sliding cavity 14 has a straight hole 15 corresponding to the deceleration hole 43.

[0052] The deceleration disc 5 is rotatably arranged in the plug-in cavity 21. The deceleration disc 5 has a deceleration rod 51 coaxially arranged therewith. The deceleration rod 51 has a second deceleration structure 52 at one end away from the deceleration disc 5. The second deceleration structure 52 is suitable for cooperating with the first deceleration structure 44 to make the upper body and the sliding core 4 slide relative to each other during the process of inserting the plug-in section 12 into the plug-in cavity 21, so as to ensure that the insertion section can be inserted into place and the clamping block 3 can be smoothly clamped into the clamping hole 23.

[0053] like Figure 10 As shown, the deceleration rod 51 of this embodiment will enter the deceleration hole 43 of the sliding core 4 through the straight hole 15 during the process of the plug-in section 12 of the upper connecting member 1 being inserted into the plug-in cavity 21 of the lower connecting member 2. In the subsequent falling process of the wind turbine tower, the first deceleration structure 44 in the deceleration hole 43 cooperates with the second deceleration structure 52 on the deceleration rod 51 to slow down the speed at which the sliding core 4 follows the falling of the wind turbine tower and the upper body, so that the sliding core 4 slides upward relative to the upper body. During this process, the insertion surface 31 of the clamping block 3 will contact the side wall at the end of the plug-in cavity 21 and move toward the sliding cavity under the drive of the side wall at the end of the plug-in cavity 21. 14 slides radially inward to ensure that the plug-in section 12 can be plugged into place. When the plug-in section 12 is plugged into place, the abutment section 11 abuts against the port of the plug-in cavity 21. The sliding core 4 then slides downward relative to the sliding cavity 14 under the action of its own gravity. In the process of the sliding core 4 sliding downward, the driving surface 42 on the sliding core 4 will contact the end of the clamping block 3 close to the sliding core 4 and drive the clamping block 3 to slide radially outward toward the sliding cavity 14 until the end of the clamping block 3 away from the sliding core 4 is clamped into the clamping hole 23. The fixed connection between the upper connecting member 1 and the lower connecting member 2 is completed through the cooperation of the clamping block 3 and the clamping hole 23.

[0054] Through the above configuration, this embodiment can automatically complete the fixed connection between the upper connector 1 and the lower connector 2 during the connection process, eliminating the need for manual fixed connection of the upper connector 1 and the lower connector 2 after the upper connector 1 and the lower connector 2 are docked. This enables this embodiment to solve the problems of existing large-scale connection devices requiring a large amount of construction equipment and complex installation steps, improve the connection efficiency of the wind turbine tower and foundation, and thus to a certain extent reduce the proportion of wind turbine installation costs in the wind turbine construction cost.

[0055] It is understandable that the insertion surface 31 of the clamping block 3 and the driving surface 42 of the sliding core 4 can be arc-shaped surfaces or inclined surfaces, and this embodiment does not impose any limitation on this.

[0056] Furthermore, the clamping block 3 has a roller 32 disposed on one end thereof near the sliding core 4, and the clamping block 3 contacts the driving surface 42 via the roller 32. The roller 32 can reduce the friction between the clamping block 3 and the driving surface 42 when the driving surface 42 on the sliding core 4 drives the clamping block 3 to slide, thereby increasing the sliding speed of the clamping block 3.

[0057] Furthermore, one of the first deceleration structure 44 and the second deceleration structure 52 is an arc-shaped protrusion, and the other is an arc-shaped groove.

[0058] like Figure 8 As shown, the arc-shaped protrusion of this embodiment will be inserted into the arc-shaped groove after the deceleration rod 51 is inserted into the deceleration hole 43. Friction will be generated between the arc-shaped protrusion and the arc-shaped groove during the continued falling of the wind turbine tower and the upper connecting member 1, thereby slowing down the speed at which the sliding core 4 follows the falling of the wind turbine tower and the upper main body, and realizing differential movement of the upper main body and the sliding core 4.

[0059] Furthermore, it also includes a positioning plate 6, which is rotatably set at the bottom end of the plug-in cavity 21 and fixedly connected to the speed reducer 5. The positioning plate 6 has a positioning cam 61, and the bottom end of the plug-in cavity 21 has a stopping tooth 24. The stopping tooth 24 is suitable for cooperating with the positioning cam 61 to position the speed reducer 5.

[0060] like Figure 7 As shown, in this embodiment, before the upper connecting member 1 and the lower connecting member 2 are connected, the deceleration plate 5 can be rotated until the stop tooth 24 abuts against the positioning cam 61, thereby positioning the deceleration plate 5 to ensure that the arc-shaped protrusion can be accurately inserted into the arc-shaped groove when the deceleration rod 51 is subsequently inserted into the deceleration hole 43.

[0061] Optionally, one of the speed reduction plate 5 and the positioning cam 61 has a threaded connection portion 62 , and the other has a threaded connection hole 53 . The speed reduction plate 5 and the positioning plate 6 are suitable for being fixedly connected by screwing the threaded connection portion 62 and the threaded connection hole 53 .

[0062] It should be noted that the fixed connection between the upper connector 1 and the lower connector 2 of the present invention is not limited to the above-described structure, and may be achieved through other structures in other embodiments. For example, in other specific embodiments of the present invention, threaded holes and connection holes may be provided on the insertion section of the upper connector 1 and the side walls of the insertion cavity 21 of the lower connector 2, respectively. After the insertion section of the upper connector 1 is inserted into place, the upper connector 1 and the lower connector 2 are fixedly connected using threaded fasteners such as bolts.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A wind turbine tower and foundation connector, characterized in that: include: An upper connecting member (1), the upper connecting member (1) comprising an upper main body, the upper main body comprising an abutting section (11) and an inserting section (12), the radial dimension of the abutting section (11) being larger than the radial dimension of the inserting section (12), and the inserting section (12) further comprising a plurality of centering blocks (13) arranged at intervals on its outer wall; A lower connecting member (2), the lower connecting member (2) comprising a lower main body, the lower main body having an inserting cavity (21) opened along its axial direction, the inserting section (12) being suitable for being inserted into the inserting cavity (21) and being fixedly connected to the side wall of the inserting cavity (21) so as to fixedly connect the upper connecting member (1) and the lower connecting member (2), the side wall of the inserting cavity (21) also having a plurality of centering grooves (22) for inserting the centering blocks (13), the number and shape of the centering grooves (22) matching the number and shape of the centering blocks (13); A plurality of clamping blocks (3), the upper body having a sliding cavity (14) opened along its axial direction, the plurality of clamping blocks (3) being radially slidably arranged on the side wall of the sliding cavity (14) of the plug-in section (12), the side wall of the plug-in cavity (21) having a plurality of clamping holes (23) for the clamping blocks (3) to be clamped in, and the clamping block (3) having an insertion surface (31) at one end close to the clamping hole (23); A sliding core (4), wherein the sliding core (4) is slidably arranged in the sliding cavity (14), the sliding core (4) has a plurality of grooves (41) corresponding to the clamping block (3), the grooves (41) have a driving surface (42), and the driving surface (42) can drive the clamping block (3) to slide, the bottom surface of the sliding core (4) has a deceleration hole (43) opened along its axis, the side wall of the deceleration hole (43) has a first deceleration structure (44), and the bottom wall of the sliding cavity (14) has a straight hole (15) corresponding to the deceleration hole (43); A deceleration disc (5), the deceleration disc (5) is rotatably arranged in the plug-in cavity (21), the deceleration disc (5) has a deceleration rod (51) coaxially arranged therewith, the deceleration rod (51) has a second deceleration structure (52) at one end away from the deceleration disc (5), the second deceleration structure (52) is suitable for cooperating with the first deceleration structure (44) so that the upper body and the sliding core (4) slide relative to each other during the process of inserting the plug-in section (12) into the plug-in cavity (21), so as to ensure that the plug-in section can be inserted into place and the clamping block (3) can be smoothly clamped into the clamping hole (23).

2. The wind turbine tower and foundation connector according to claim 1, characterized in that: The centering block (13) and the centering groove (22) are in the shape of an inverted isosceles trapezoid.

3. The wind turbine tower and foundation connector according to claim 1, wherein: The outer wall of the plug-in section (12) is provided with two symmetrically arranged centering blocks (13), and the inner side wall of the plug-in cavity (21) is provided with two symmetrically arranged centering grooves (22).

4. The wind turbine tower and foundation connector according to claim 1, wherein: The end of the plug-in section (12) away from the abutting section (11) is in the shape of an inverted truncated cone.

5. The wind turbine tower and foundation connector according to claim 1, wherein: The clamping block (3) has a rolling roller (32) at one end close to the sliding core (4), and the clamping block (3) contacts the driving surface (42) through the roller (32).

6. The wind turbine tower and foundation connector according to claim 1, wherein: The insertion surface (31) and the driving surface (42) are respectively arc-shaped surfaces or inclined surfaces.

7. The wind turbine tower and foundation connector according to claim 1, wherein: One of the first deceleration structure (44) and the second deceleration structure (52) is an arc-shaped protrusion, and the other is an arc-shaped groove.

8. The wind turbine tower and foundation connector according to claim 7, characterized in that: The invention also includes a positioning plate (6), which is rotatably arranged at the bottom end of the plug-in cavity (21) and fixedly connected to the deceleration plate (5), and the positioning plate (6) has a positioning cam (61). The bottom end of the plug-in cavity (21) has a stopping tooth (24), and the stopping tooth (24) is suitable for cooperating with the positioning cam (61) to position the deceleration plate (5).

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