Low-installation-height vulcanized-bonded vibration-damping fastener

Abstract

A low-installation-height vulcanized-bonded vibration-damping fastener, comprising a lower base plate (1), an intermediate layer (2), and an upper base plate (3). The lower base plate (1) is of a full constraint frame structure. The upper base plate (3) is embedded within the frame structure of the lower base plate (1). A pull-out prevention limiting structure (4) is disposed between the upper base plate (3) and the lower base plate (1). The intermediate layer (2) fills the gap between the lower base plate (1) and the upper base plate (3). The vibration-damping fastener solves the problems of excessive installation height and the failure to provide full constraint in vulcanized-bonded fasteners.

Description

Low-mounting-height vulcanization bonding damping fastener TECHNICAL FIELD

[0001] The present application belongs to the field of rail transit damping fasteners, and particularly relates to a low-mounting-height vulcanization bonding damping fastener. BACKGROUND

[0002] With the rapid growth of China's economy and the rapid increase of urban population, urban traffic problems are becoming increasingly acute. Rail transit is a form of transportation with large carrying capacity, punctuality and energy saving, which makes rail transit develop rapidly. The subway is the main form of urban rail transit.

[0003] Since the subway usually passes through densely populated areas and areas with concentrated upper property during operation. This part of the area is usually sensitive to environmental vibration and noise, and excessive vibration is also not conducive to the safe operation of the subway, so the subway damping and noise reduction work is also paid more and more attention. The current subway damping measures mainly include damping bed and damping track, and the damping track mainly relies on damping fasteners to achieve damping effect. Common damping fasteners include double-layer nonlinear damping fasteners, vulcanization bonding damping fasteners, floating rail damping fasteners, etc., which cover medium and high damping ranges.

[0004] The vulcanization bonding damping fastener is an elastic split type fastener, which relies on rubber adhesive to vulcanize the upper and lower iron pads and rubber into one body, and constrains the steel rail through elastic strips. This type of fastener can adjust the stiffness of the fastener by adjusting the material of the rubber, and utilize the compression deformation of the rubber to meet the damping performance. At the same time, the spiral spikes are fixed without penetrating the elastic layer, avoiding the loss of elasticity caused by tightening the bolts during installation of the fastener.

[0005] The existing vulcanization bonding fasteners are more representative, including the Cologne egg fastener and the Lord fastener. The Cologne egg fastener has a higher installation height, which exceeds 60mm. For existing line operation and reconstruction projects, it has poor compatibility with the installation height of ordinary fasteners. At the same time, the Cologne egg fastener belongs to a shear type damping fastener, which is easy to cause track wear due to its shear type structure, so it is rarely used for new line projects. The Lord fastener is a compression type damping fastener, which vulcanizes the upper and lower iron pads and rubber together to achieve damping effect by relying on the rubber layer. The Lord fastener does not contain a track pad, and the height is 50mm, which is still higher than the installation height of ordinary fasteners. For existing line reconstruction projects, it is required that the installation height of the fastener is as low as possible to match the installation height of ordinary fasteners, avoid height adjustment or reduce the workload of height adjustment, and the safety of the fastener without height adjustment pad is better.

[0006] The existing vulcanized adhesion fasteners, such as the invention patent CN 114657821 A "Rail vibration damping fastener with high transverse stability and variable stiffness method thereof", CN 221003631 U "High-stability vulcanized adhesion fastener", CN 220767567 U "Ducking type vibration damping fastener", etc., all adopt the design of upper and lower iron base plates and vulcanized rubber laminates, and the installation height is too high; the lower iron base plate is provided with a shoulder structure on both sides, which effectively improves the transverse stiffness of the fastener, but does not realize the constraint of the upper iron base plate in the longitudinal direction, that is, the lower iron base plate is not designed as a full constraint structure, and the upper iron base plate cannot be fully constrained. SUMMARY

[0007] Therefore, the present application discloses a low-installation-height vulcanized adhesion vibration damping fastener, which adopts a full-constraint-frame embedded structure design to realize low installation height of the vulcanized adhesion vibration damping fastener, aiming to solve the problem of high installation height of the existing vulcanized adhesion type fastener and the inability to be fully constrained.

[0008] A low-installation-height vulcanized adhesion vibration damping fastener, the fastener comprising a lower base plate, an intermediate layer and an upper base plate, wherein the lower base plate, the intermediate layer and the upper base plate are vulcanized into one body by an adhesive; the lower base plate adopts a full-constraint-frame structure, the upper base plate is embedded in the frame structure of the lower base plate, and the intermediate layer fills the gap between the lower base plate and the upper base plate.

[0009] Further, the lower base plate comprises a full-constraint-frame and a receiving part, the receiving part is arranged inside the full-constraint-frame, outer shoulder structures are arranged at two diagonal positions of the full-constraint-frame, and spiral spike holes are arranged at the other two diagonal positions.

[0010] Further, the spiral spike hole is an oblong hole.

[0011] Further, two side plates are arranged on the transverse sides of the outer shoulder structure, and an upper plate is arranged on the upper side of the outer shoulder structure in the longitudinal direction.

[0012] Further, an inner shoulder structure is arranged on the upper base plate corresponding to the position of the outer shoulder structure, an anti-pulling-off structure is arranged outside the inner shoulder structure, and the anti-pulling-off structure is fixedly connected with the inner shoulder structure.

[0013] Further, an anti-pulling-off limiting structure is arranged between the inner shoulder structure and the outer shoulder structure, the anti-pulling-off limiting structure comprises a limiting structure and an anti-pulling-off structure, the limiting structure comprises the outer shoulder structure, the side plates and the upper plate, and the limiting structure is a hollow cavity structure; the anti-pulling-off structure is a triangular prism structure with a straight triangle cross section, wherein the straight side of the triangular prism is fixedly connected with the inner shoulder structure.

[0014] Further, the fastener slowly moves downward along the inclined edge of the anti-pulling-off structure during service until the upper straight edge of the anti-pulling-off structure is clamped with the lower surface of the upper baffle of the limiting structure.

[0015] Further, the intermediate layer is provided with a through hole corresponding to the position of the spiral spike hole, wherein the through hole is larger than the spiral spike hole; and the intermediate layer is provided with a middle shoulder structure corresponding to the position of the outer shoulder structure, and the middle shoulder structure is filled between the outer shoulder structure and the inner shoulder structure.

[0016] Further, the contained part of the intermediate layer is provided with a square hole, and the diagonal two sides of the contained part are provided with drainage holes, and the square hole and the drainage hole longitudinally penetrate the intermediate layer.

[0017] Further, the intermediate layer adopts a high torsion resistance structure design, and the bottom of the intermediate layer adopts a staggered arrangement of nail column structures, wherein the nail column adopts a conical structure design. Beneficial effects

[0018] Compared with the prior art, the present application has the following beneficial effects:

[0019] 1) The fastener adopts a full constraint structure design concept, and the whole fastener adopts a frame embedded structure design, so as to realize low installation height design of the fastener, and the lower iron pad adopts a full constraint frame structure matched with two end shoulder structures and an anti-pulling-off structure, so as to realize full constraint of the upper iron pad. The full constraint structure can effectively reduce the installation height of the fastener, and greatly improve the stability of the track.

[0020] 2) The rubber at the bottom of the vulcanized and bonded fastener adopts a nail column structure, and the staggered arrangement of the nail column structure can effectively resist horizontal overturning effect.

[0021] 3) The nail column structure at the bottom of the rubber layer adopts a conical structure design, different upper loads act on the fastener, the contact area of the nail column at the bottom of the rubber layer with the sleeper is different, and the characteristics of "low load and low stiffness, high load and high stiffness" are realized. BRIEF DESCRIPTION OF DRAWINGS

[0022] Fig. 1 is a general view of a low installation height vulcanized and bonded damping fastener according to the present application;

[0023] Fig. 2 is a component diagram of the vulcanized and bonded damping fastener according to the present application;

[0024] Fig. 3 is a structure diagram of the lower iron pad according to the present application;

[0025] Fig. 4 is a structure diagram of the intermediate layer according to the present application;

[0026] Fig. 5 is a structure diagram of the bottom of the intermediate layer according to the present application;

[0027] Fig. 6 is a structure diagram of the upper iron pad according to the present application;

[0028] Figure 7 is a full-constrained structure of the vulcanized rubber bonding shock-absorbing fastener of the present application;

[0029] Figure 8 is an enlarged view of part A in Figure 7.

[0030] Reference signs: lower cushion plate 1, full-constrained frame 11, outer shoulder structure 111, side baffle 1111, upper baffle 1112, outer baffle 1113; accommodating portion 12; helical stud hole 13, first outer fitting surface 131, first chamfer 1311, second outer fitting surface 132, tooth 133; positioning buckle 14; intermediate layer 2, constrained frame 21, middle shoulder structure 211, middle side baffle 2111, middle upper baffle 2112; accommodated portion 22, square hole 221, drainage hole 222; through hole 23, first inner fitting surface 231, second chamfer 2311, second inner fitting surface 232, third inner fitting surface 233, positioning surface 24, limiting cavity 25, first gap 261, second gap 262; upper cushion plate 3, inner shoulder structure 31, spring strip accommodating portion 32, spring strip accommodating hole 321, third outer fitting surface 333; anti-pulling limiting structure 4, limiting structure 41, anti-pulling structure 42; DETAILED DESCRIPTION

[0031] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The description of "first", "second", etc. in the embodiments of the present application is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features with "first", "second" can explicitly or implicitly include at least one of the features. In addition, the technical solutions of various embodiments can be combined with each other, but it must be based on the realization of ordinary skilled in the art, when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, nor within the protection scope claimed by the present application.

[0032] The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0033] Embodiment 1

[0034] In the prior art, the conventional fastener adopts the design of upper and lower cushion plates and vulcanized rubber laminates, and the installation height is too high; at the same time, the existing conventional fastener only applies horizontal constraint to the upper cushion plate, and does not apply longitudinal constraint to the upper cushion plate, that is, it is not a full-constrained structure.

[0035] In order to solve the problem of high installation height of the vulcanization bonding type fastener in the prior art and the inability to perform full constraint, the embodiment provides a low installation height vulcanization bonding vibration reduction fastener, as shown in FIGS. 1-7, the vulcanization bonding type fastener comprises a lower base plate 1, an intermediate layer 2 and an upper base plate 3, the lower base plate 1 and the upper base plate 3 are made of the same material and can be metal materials such as iron or steel; wherein the lower base plate 1 adopts a full constraint frame type structure, specifically, the lower base plate 1 adopts a frame type structure, combined with two side outer shoulder structures 111 and a limiting structure 41, to realize full constraint of the lower base plate 1 on the upper base plate 3; the upper base plate 3 is embedded in the frame structure of the lower base plate 1, and the inner shoulder structure 31 is also embedded in the outer shoulder structure 111; the intermediate layer 2 fills the gap between the lower base plate 1 and the upper base plate 3, to realize full constraint of the lower base plate 1 on the upper base plate 3, and can effectively reduce the installation height of the fastener and realize low installation height design of the fastener.

[0036] As shown in FIG. 3, the lower base plate 1 adopts a full constraint frame 11, which can realize full constraint of the upper base plate 3 in three directions; the receiving part 12 is arranged inside the full constraint frame 11 and is used for accommodating the intermediate layer 2 and the upper base plate 3, to realize low installation design of the fastener structure;

[0037] The outer shoulder structure 111 is arranged at two diagonal positions of the full constraint frame 11, the outer shoulder structure 111 comprises a side baffle 1111, an upper baffle 1112 and an outer baffle 1113, the outer baffle 1113 is provided with the side baffle 1111 on the transverse sides thereof, the two side baffles 1111 have transverse constraint on the upper base plate 3 and can effectively reduce the transverse displacement of the rail head, which is conducive to driving safety; the upper baffle 1112 is arranged on the upper side of the outer baffle 1113 in the longitudinal direction; the limiting structure 41 is arranged inside the outer shoulder structure 111 and is a hollow cavity structure inside the outer shoulder structure 111; the other two diagonal positions are provided with upper and lower through screw spikes 13, the screw spikes 13 are used for installing screw spikes, different hole distances of the screw spikes 13 can be arranged according to the line conditions, to adapt to fasteners of different hole distances; wherein the screw spikes 13 are provided with teeth 133 at the top thereof, and the screw spikes 13 are provided with a positioning buckle 14 on one side close to the outer edge thereof.

[0038] As shown in FIG. 5, the shape of the upper base plate 3 matches the shape of the full constraint frame 11 and the accommodating portion 12 of the lower base plate 1, and is slightly smaller than the accommodating portion 12 of the lower base plate 1; wherein the upper base plate 3 does not have a helical spike hole or other arrangement corresponding to the position of the helical spike hole 13 of the lower base plate 1, i.e. the upper base plate 3 does not cover the helical spike hole 13 of the lower base plate 1, ensuring that the helical spike hole does not pass through the upper base plate. The upper base plate 3 is provided with an inner shoulder structure 31 corresponding to the position of the outer shoulder structure 111, further, a spring strip accommodating portion 32 is provided on the inner side of the inner shoulder structure 31, and the spring strip accommodating portion 32 is provided with a spring strip containing hole 321; an anti-pull-out structure 42 is provided on the outer side of the inner shoulder structure 31, and the anti-pull-out structure 42 is a triangular prism structure with a right-angled triangle cross section, wherein one of the right-angled sides is fixedly connected with the inner shoulder structure 31.

[0039] As shown in FIGS. 6-7, an anti-pull-out limiting structure 4 is arranged between the inner shoulder structure 31 and the outer shoulder structure 111, which can effectively prevent the upward displacement of the upper base plate 3, and realize the longitudinal constraint of the upper base plate 3 by the lower base plate 1.

[0040] Specifically, the anti-pull-out limiting structure 4 includes a limiting structure 41 and an anti-pull-out structure 42. During the service of the fastener, the upper base plate 3 slowly moves downward along the inclined edge of the anti-pull-out structure 42 after being stressed, until the upper edge right-angled side of the anti-pull-out structure 42 is clamped with the lower surface of the upper baffle 1112 of the limiting structure 41, at which time the lower base plate 1 realizes the longitudinal constraint of the upper base plate 3; at the same time, the outer shoulder structure 111 and the inner shoulder structure 31 on the horizontal two sides are in a fastened state through the anti-pull-out limiting structure 4, realizing the horizontal constraint of the upper base plate 3 by the lower base plate 1; in this state, a gap will appear between the shoulder positions of the upper base plate 3 and the lower base plate 1, specifically, a first gap 261 is formed between the upper baffle 1112 and the inner shoulder structure 31, and a second gap 262 is formed between the upper baffle 1112 and the anti-pull-out structure 42, and the intermediate layer 2 is filled between the first gap 261 and the second gap 262 (the intermediate layer is omitted in FIG. 8 for the sake of clear and easy reading of the drawings); during the service of the fastener, the first gap 261 and the second gap 262 between the upper base plate 3 and the lower base plate 1 are filled with the intermediate layer 2, which can provide a certain buffer zone for the relative movement between the upper and lower base plates, prevent the occurrence of excessive local stress, and effectively improve the service life of the fastener.

[0041] After the upper base plate 3 is embedded in the frame structure of the lower base plate 1, there is a certain gap between the upper base plate 3 and the lower base plate 1, and the gap is filled with rubber or other elastic materials as an intermediate layer 2, and the damping effect is realized by relying on the intermediate layer 2; in addition, the intermediate layer 2 adopts a high torsional resistance rubber structure, which can improve the torsional resistance effect of the fastener; the bottom of the intermediate layer 2 adopts a pin column type structure, and through the staggered arrangement of the pin column type structure, the horizontal overturning effect can be effectively resisted; at the same time, the number of pins can be adjusted, and then the vertical node static stiffness of the fastener can be changed. Among them, the pin adopts a conical structure design, and different upper loads act on the fastener, the contact area of the pin column at the bottom of the intermediate layer 2 is different, and the stiffness can be adjusted: low load low stiffness, high load high stiffness.

[0042] As shown in FIGS. 1-4, the intermediate layer 2 fills the gap between the upper and lower base plates 1 and the upper base plate 3, and the shape of the intermediate layer 2 matches the gap after the lower base plate 1 and the upper base plate 3 are embedded. Specifically, the intermediate layer 2 includes a constrained frame 21 and a contained portion 22, the constrained frame 21 corresponds to the full constrained frame 11 of the lower base plate 1, and the contained portion 22 is a groove shape and is clamped inside the containing portion 12. The upper base plate 3 is clamped in the hollow groove inside the contained portion 22.

[0043] Specifically, the intermediate layer 2 is provided with a through hole 23 corresponding to the position of the spiral spike hole 13 of the lower base plate 1, and the through hole 23 is slightly larger than the spiral spike hole 13, that is, the through hole 23 does not cover the position of the spiral spike hole 13, so as to ensure that the spiral spike does not pass through the intermediate layer 2. The first inner fitting surface 231 of the edge of the through hole 23 is fitted on the first outer fitting surface 131 of the edge of the spiral spike hole 13, and the first inner fitting surface 231 and the first outer fitting surface 131 are flush in height, wherein the first chamfer 1311 and the second chamfer 2311 are fitted with each other, which can better fix the position between the intermediate layer 2 and the lower base plate 1. The second inner fitting surface 232 of the edge of the through hole 23 is fitted and clamped on the second outer fitting surface 132 of the edge of the spiral spike hole 13, and the height of the second inner fitting surface 232 is greater than the height of the second inner fitting surface 132, so that the intermediate layer 2 is clamped on the lower base plate 1 while ensuring that the through hole 23 does not cover the spiral spike hole 13, thereby achieving good damping and buffering effect; the third inner fitting surface 233 of the intermediate layer 2 is fitted with the third outer fitting surface 333 of the upper base plate 3, so that the upper base plate 3 is clamped in the inner groove of the intermediate layer 2.

[0044] The intermediate layer 2 is provided with a middle shoulder structure 211 corresponding to the position of the outer shoulder structure 111, the middle shoulder structure 211 is similar in shape to the outer shoulder structure 111, the inner surface of the middle shoulder structure 211 is attached to the outer surface of the upper shoulder structure 111, that is, the middle shoulder structure 211 covers the outer shoulder structure 111, the middle shoulder structure 211 is internally provided with a positioning cavity 25, the positioning cavity 25 is jointly formed by the inner cavity of the middle shoulder structure 211 and the positioning surface 24, and the anti-pulling-off structure 42 is tightly matched with the positioning cavity 25 during service of the fastener; specifically, the positioning surface 24 in the middle shoulder structure 211 is attached to the inclined surface of the right triangular prism of the anti-pulling-off structure 41, the longitudinal displacement of the anti-pulling-off structure 41 is limited, and the upper base plate 3 is further longitudinally constrained; the positioning surface 24 is arc-shapedly connected with the contained part 22 of the intermediate layer 2, and the positioning surface 24 below is filled with the intermediate layer 2, wherein the positioning surface 24 is an inclined surface, and the design that the inclined surface is attached and filled effectively increases the bonding area of the intermediate layer 2, and the fatigue performance of the fastener can be improved.

[0045] The contained part 22 is internally provided with a square hole 221 penetrating through the longitudinal height of the entire intermediate layer 2, the square hole 221 is designed to adjust the rigidity of the fastener, the larger the square hole 221 is, the lower the rigidity of the fastener is, and the smaller the area of the square hole 221 is, the higher the rigidity of the fastener is; in addition, the contained part 22 is provided with drainage holes 222 on the opposite sides.

[0046] Preferably, in the anti-pulling-off limiting structure 4, the lower surface of the anti-pulling-off structure 42 is designed as an inclined surface at a certain angle, which can effectively increase the bonding area of the intermediate layer 2 and increase the thickness of the intermediate layer 2 between the upper base plate 3 and the lower base plate 1, is conducive to rigidity adjustment, and can improve the fatigue performance of the fastener.

[0047] The lower base plate 1, the upper base plate 3 and the intermediate layer 2 are vulcanized into one body by means of an adhesive; after vulcanization and molding, the upper base plate 3 and the intermediate layer 2 are all limited on the full constraint frame of the lower base plate, which can effectively reduce the installation height of the fastener and realize the low installation height design of the fastener; at this time, the installation height of the fastener in the application can be as low as 40±5mm, and the lower base plate 1 can also realize full constraint on the upper base plate 3, thereby improving the overall stability of the fastener.

[0048] In addition, during construction of the vulcanized and bonded fastener, the lower end is installed on the sleeper, slab track bed and other base components of the track foundation through a spiral spike, and the upper end is constrained on the rail through a spring strip; meanwhile, for the conventional parts such as the rail base plate, spiral spike and spring strip, the structure and assembly can adopt the existing technology, and details are not described herein.

[0049] Further, the vulcanized bonding type fastener adopts a rail pitch block design, and the spiral spike adopts a long circular hole design, so that the rail pitch adjustment amount can be increased, that is, the rail pitch of the steel rail can be adjusted in a large range. Compared with the fastener without the rail pitch block design, when the rail pitch needs to be finely adjusted on site, the fastener of the application does not need to disassemble the spiral spike, but can achieve the fine adjustment of the rail pitch by replacing the rail pitch block, while the fastener without the rail pitch block can only disassemble the spiral spike to achieve the fine adjustment of the rail pitch.

[0050] Although the present application has been disclosed with reference to the above embodiments, it is not intended to limit the application. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the application. Therefore, the scope of protection of the application should be subject to the scope defined by the claims.

Claims

1. A low profile, vulcanized bonded vibration damping fastener characterized by, The fastener comprises a lower base plate (1), an intermediate layer (2) and an upper base plate (3); the lower base plate (1) adopts a full-constraint frame structure, the upper base plate (3) is embedded in the frame structure of the lower base plate (1), and an anti-pulling-off limiting structure (4) is arranged between the upper base plate (3) and the lower base plate (1); the intermediate layer (2) fills the gap between the lower base plate (1) and the upper base plate (3).

2. The fastener of claim 1, wherein The lower base plate (1) comprises a full-constraint frame (11) and a receiving part (12), the receiving part (12) is arranged inside the full-constraint frame (11), two diagonal positions of the full-constraint frame (11) are provided with outer shoulder structures (111), and the other two diagonal positions are provided with spiral spike holes (13).

3. The fastener of claim 2, wherein The spiral spike hole (13) is a long circular hole.

4. The fastener of claim 2, wherein The outer shoulder structure (111) comprises side baffles (1111), upper baffles (1112) and outer baffles (1113), two side baffles (1111) are arranged on the transverse sides of the outer baffle (1113), and the upper baffle (1112) is arranged on the upper side of the outer baffle (1113) in the longitudinal direction.

5. The fastener of claim 1, wherein The upper base plate (3) is provided with an inner shoulder structure (31) corresponding to the position of the outer shoulder structure (111), an anti-pulling-off structure (42) is arranged outside the inner shoulder structure (31), and the anti-pulling-off structure (42) is fixedly connected with the inner shoulder structure (31).

6. The fastener of claim 5, wherein, The anti-pulling-off limiting structure (4) is arranged between the inner shoulder structure (31) and the outer shoulder structure (111), the anti-pulling-off limiting structure (4) comprises a limiting structure (41) and an anti-pulling-off structure (42), the limiting structure (41) is a hollow cavity structure inside the outer shoulder structure (111); the anti-pulling-off structure (42) is a triangular prism structure with a right-angled triangle cross section, and the right-angled side of the triangular prism is fixedly connected with the inner shoulder structure (31).

7. The fastener of claim 6, wherein During service, the upper base plate (3) slowly moves downward along the inclined edge of the anti-pulling-off structure (42) until the upper edge right-angled side of the anti-pulling-off structure (42) is clamped with the lower surface of the upper baffle (1112) of the limiting structure (41).

8. The fastener of claim 1, wherein The intermediate layer (2) is provided with a through hole (23) corresponding to the position of the spiral spike hole (13), and the through hole (23) is larger than the spiral spike hole (13); the intermediate layer (2) is provided with a middle shoulder structure (211) corresponding to the position of the outer shoulder structure (111), and the inner surface of the middle shoulder structure (211) is attached to the outer surface of the outer shoulder structure (111).

9. The fastener of claim 8, wherein, The receiving part (22) of the intermediate layer (2) is provided with a square hole (221), and the diagonal sides of the receiving part (22) are provided with drainage holes (222), and the square hole (221) and the drainage hole (222) penetrate through the intermediate layer (2).

10. The fastener of claim 8, wherein, The intermediate layer (2) adopts a high torsion-resistant structure design, and the bottom of the intermediate layer (2) adopts a staggered arrangement of spike column structures, wherein the spike column adopts a conical structure design.

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