Thorn-raising steel backing with hook-type thorn-raising structure

Abstract

The utility model relates to the technical field of thorn-raising steel backing, in particular to a thorn-raising steel backing with a hook-type thorn-raising structure, an upper shell is arranged above a brake disc, and the shearing strength of a friction block material is increased by bent thorns of a steel plate. Bent thorns and grooves which are uniformly distributed are arranged on the surface of the plate body, the bent thorns are formed by upturning and bending a plate material in the grooves, the bent thorns are 1.5-3mm higher than the plane of the plate body, the distance between the thorns and the periphery of the thorns is larger than or equal to 4mm, steel fibers in friction materials are prevented from being blocked by the thorns and cannot press the plane of a steel back, and the bent thorns of the steel plate can be sprung through one-time downward pressing. The steel backing is circularly cooled by a cooling device and an infusion pump, the steel backing and a friction layer can be bonded more firmly by a bonding layer made of phenolic resin and a heat insulation layer made of ceramic fiber, heat transferred to the steel backing is greatly reduced, and the friction coefficient of the steel backing is increased. The protective layer made of rubber can better protect the steel backing, and the service life of the steel backing is greatly prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of thorny steel backs, in particular to a thorny steel back with a hook-type thorny structure. Background Art

[0002] Brake pads are generally provided with punched holes on the steel back to increase the shear force between the steel back and the friction material during braking. When punching and punching the steel back, it is easy to deform the steel back, which affects the combination of the steel back and the friction material and reduces the strength of the steel back to a certain extent. In addition, the braking effect of the current brake pads with punched steel backs is not ideal. The steel back and the friction material are often separated during braking, which poses a great safety hazard. The punched steel back is easy to deform the steel back, which affects the combination of the steel back and the friction material and reduces the strength of the steel back to a certain extent. In addition, the braking effect of the current brake pads with punched steel backs is not ideal. The steel back and the friction material are often separated during braking, which poses a great safety hazard.

[0003] Generally, the structure of the burr structure is weak and the burrs are densely arranged. The steel fibers in the friction material are blocked by the burrs, and the friction material cannot be pressed to the bottom of the steel back, so that there is a gap between the steel back and the friction material. There is a risk of the steel back and the friction material falling off. The existing steel back will have too high a temperature during braking, which will cause the steel plate to deform and greatly weaken the braking effect of the brake device. Utility Model Content

[0004] The main purpose of the utility model is to provide a thorn steel back with a hook-type thorn structure to solve the problem of adding a thorn steel back with a hook-type thorn structure proposed in the related art.

[0005] In order to achieve the above-mentioned purpose, according to one aspect of the utility model, a thorny steel back with a hook-type thorny structure is provided, including: a brake disc, an upper shell is arranged above the brake disc, a side shell is arranged on the side wall of the upper shell, a first threaded hole is penetrated through the upper end of the side wall of the side shell, a first bolt is arranged in the first threaded hole, the first bolt passes through the first threaded hole and is fixedly connected to the upper shell, a fixing rod is fixedly arranged between the side shells on both sides, and a friction brake part is arranged on the fixing rod.

[0006] Furthermore, the friction brake part includes a steel back, a plurality of mounting holes are formed through the upper end of the steel back, the mounting hole has a square cross-section, the fixing rod has a square cross-section, and the fixing rod has the same cross-section area as the mounting hole.

[0007] Furthermore, a plurality of evenly arrayed curved thorns are fixedly provided on a side wall of one side of the steel back, a groove is provided at the lower end of the curved thorn, the cross section of the side wall of the curved thorn is in a hook shape, and the cross section of the front end of the curved thorn is in a rectangular shape.

[0008] Furthermore, the distance between the adjacent curved thorns on both sides is greater than or equal to 4 mm, the height of the side wall of the curved thorn is 1.5 to 3 mm, and the cross-section of the groove is square.

[0009] Furthermore, an adhesive layer is fixedly provided on the bent thorn, a heat insulating layer is fixedly provided on the side wall of the adhesive layer, a friction layer is fixedly provided on the side wall of the heat insulating layer, and a plurality of connecting grooves are penetrated through the friction layer.

[0010] Furthermore, the steel back is preferably made of stainless steel metal, and a protective layer is provided on the surface of the steel back, and the protective layer is preferably made of rubber material.

[0011] Furthermore, the adhesive layer is preferably made of phenolic resin, and the heat insulation layer is preferably made of ceramic fiber.

[0012] Furthermore, a cooling layer is fixedly provided on the side wall of the other side of the steel back, a plurality of fixing plates are fixedly provided on the side wall of the cooling layer, a second threaded hole is penetrated through the fixing plate, and a second bolt is provided in the second threaded hole.

[0013] Furthermore, a plurality of communication ports are formed through the surface of the cooling layer, a connection plug is fixedly provided on the inner wall of the communication port, and a moving block is provided on the inner wall of the connection plug.

[0014] Furthermore, a cooling device is provided on one side of the cooling layer, a liquid outlet pipe is fixedly provided on the upper end of the cooling device, a third through hole is penetrated on one side of the cooling layer, one end of the liquid outlet pipe passes through the third through hole and is fixedly connected to the cooling layer, a plurality of liquid outlets in a uniform array are penetrated on the side wall at one end of the liquid outlet pipe, a first liquid pump is fixedly provided on the other end of the liquid outlet pipe, a liquid return pipe is fixedly provided on the lower end of the cooling device, a second liquid pump is fixedly provided on one end of the liquid return pipe, and the other end of the liquid return pipe is fixedly connected to the lower side wall of the cooling layer.

[0015] Compared with the prior art, the utility model has the following beneficial effects: the thorns of the steel plate increase the shear strength of the friction block material. The surface of the plate body is provided with evenly distributed thorns and grooves. The thorns are formed by bending the plate material in the grooves upward. The thorns are 1.5-3mm higher than the plane of the plate body, evenly distributed, and good-looking. The interval between the thorns is greater than or equal to 4mm, and the steel fibers in the friction material are prevented from being blocked by the thorns and cannot be pressed on the steel back plane. The thorns of the steel plate can be completed by pressing down once, and the overall extrusion thorns have little effect on the flatness, which not only improves production efficiency but also ensures quality. The cooling device and the liquid pump are used to circulate and cool the steel back, which can reduce the deformation of the steel back during the braking process and greatly improve the operating efficiency of the braking device. The bonding layer of phenolic resin material and the heat insulation layer of ceramic fiber material can make the steel back and the friction layer more firmly bonded, and greatly reduce the heat transfer to the steel back. The protective layer of rubber material can better protect the steel back and greatly improve the life of the steel back. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0017] Figure 2 A schematic diagram of the utility model as a whole;

[0018] Figure 3 It is a schematic diagram of the fixed shell of the utility model;

[0019] Figure 4 It is a schematic diagram of a side view of the friction brake part of the utility model;

[0020] Figure 5 This is a schematic diagram of the structure of the friction brake part of the utility model;

[0021] Figure 6 It is a schematic diagram of the steel back of the utility model;

[0022] Figure 7 It is a schematic diagram of the left side view of the steel back of the utility model;

[0023] Figure 8 It is a schematic diagram of the front view of the steel back of the utility model;

[0024] Fig. 9 It is a schematic diagram of the cooling device of the utility model;

[0025] Fig.10 It is a schematic diagram of the cooling part of the utility model.

[0026] Illustration Description:

[0027] 1. brake disc; 101. side shell; 102. upper shell; 103. first bolt; 104. moving block; 105. fixing rod;

[0028] 2. Steel back; 201. Bend thorn; 202. Groove; 203. Mounting hole; 204. Friction layer; 205. Heat insulation layer; 206. Adhesive layer; 207. Cooling layer; 208. Cooling device; 209. First liquid pump; 210. Second liquid pump; 211. Liquid outlet pipe; 212. Liquid outlet; 213. Liquid return pipe; 214. Fixing plate; 215. Second bolt; 216. Connecting plug; 217. Connecting port. DETAILED DESCRIPTION

[0029] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined purpose of the utility model, the specific implementation method, structure, characteristics and effects of the present invention are described in detail below in combination with the accompanying drawings and preferred embodiments.

[0030] See also Figures 1 to 10 FIG. 1 shows a thorn steel back with a hook-type thorn structure, comprising: a brake disc 1, an upper shell 102 is arranged above the brake disc 1, a side shell 101 is arranged on the side wall of the upper shell 102, a first threaded hole is penetrated through the upper end of the side wall of the side shell 101, a first bolt 103 is arranged in the first threaded hole, the first bolt 103 passes through the first threaded hole and is fixedly connected to the upper shell 102, a fixing rod 105 is fixedly arranged between the side shells 101 on both sides, and a friction brake part is arranged on the fixing rod 105. The brake disc 1 is used to cooperate with the brake device on the side wall of the brake disc 1, and the kinetic energy of the vehicle is converted into heat energy through friction, so as to achieve the purpose of deceleration or parking. The brake disc 1 is fixed on the wheel and rotates with the wheel. When the driver steps on the brake pedal, the moving block 104 of the brake caliper on the side wall of the side shell 101 is pushed by the hydraulic device, so that the friction brake part is tightly attached to the two sides of the rotating brake disc 1, generating sufficient friction to slow down the vehicle. The first bolt 103 is used to connect and fix the side shell 101 and the upper shell 102 to facilitate the disassembly and replacement of the brake device at the later stage. The fixing rod 105 is used to clamp and fix the friction brake part, so that the friction brake part can move left and right along the fixing rod 105, and squeeze the brake disc 1 for friction deceleration.

[0031] The friction brake part includes a steel back 2, and a plurality of mounting holes 203 are formed through the upper end of the steel back 2. The cross section of the mounting hole 203 is square, and the cross section of the fixing rod 105 is square. The cross section of the fixing rod 105 is the same as the cross section of the mounting hole 203. The cross section of the mounting hole 203 on the steel back 2 is the same as the cross section of the fixing rod 105, so that the steel back 2 can be clamped and fixed on the fixing rod 105.

[0032] A plurality of evenly arrayed curved thorns 201 are fixedly arranged on the side wall of one side of the steel back 2, and a groove 202 is provided at the lower end of the curved thorn 201. The cross section of the side wall of the curved thorn 201 is in the shape of a hook, and the cross section of the front end of the curved thorn 201 is rectangular. The curved thorn 201 can increase the bonding force between the steel back 2 and the friction layer 204, and the bonding strength between the friction layer 204 and the steel back 2, ensuring that the friction layer 204 will not fall off the steel back 2 during the high temperature and high pressure braking process. The cross section of the side wall of the curved thorn 201 is in the shape of a hook, and the processing device is used to press down once, and the overall extrusion and burring greatly reduces the impact on the flatness of the steel back 2, while improving the production efficiency and ensuring the burring quality of the curved thorn 201. The curved thorns 201 on the same horizontal line have the same bending direction, and the adjacent curved thorns 201 on the same vertical line have opposite directions, so that the steel back 2 can be pressed down once when processing the curved thorn 201, which is faster and more convenient.

[0033] The distance between adjacent curved thorns 201 on both sides is greater than or equal to 4mm, the height of the side wall of the curved thorn 201 is 1.5-3mm, and the cross section of the groove 202 is square. The volume of the curved thorn 201 is the same as that of the groove 202, and the processing device performs thorn processing on the steel back 2. The height of the curved thorn 201 is the length of the groove 202, and the width of the curved thorn 201 is the width of the groove 202. The cross section of the side wall of the curved thorn 201 is in the shape of a hook, which can better connect and fix the friction layer 204 to the steel back 2. The height of the side wall of the curved thorn 201 is 1.5-3mm, which can better grasp the friction layer 204, and the distribution is even and beautiful. The distance between adjacent curved thorns 201 is greater than or equal to 4mm, which can prevent the steel fibers in the friction layer 204 from being blocked by the thorns, and the friction layer 204 cannot press the bottom of the steel back 2, so that a gap is generated between the steel back 2 and the friction layer 204, resulting in the risk of the steel back 2 and the friction layer 204 falling off.

[0034] The curved thorn 201 is fixedly provided with an adhesive layer 206, and the side wall of the adhesive layer 206 is fixedly provided with a heat insulating layer 205, and the side wall of the heat insulating layer 205 is fixedly provided with a friction layer 204, and a plurality of connecting grooves are opened through the friction layer 204. The adhesive layer 206 is used to bond and fix the heat insulating layer 205 to the curved thorn 201 on the side wall of the steel back 2, and the heat insulating layer 205 and the friction layer 204 are also bonded and fixed with an adhesive made of the adhesive layer 206 material. The heat insulating layer 205 is used to isolate the high temperature generated by braking, protect the steel back 2 from heat damage, and extend its service life. The heat insulating layer 205 reduces the heat transfer between the brake pad and the steel back 2, and avoids the heat transfer to the wheel hub and the suspension system, thereby reducing the thermal impact on other parts of the vehicle. The heat insulating layer 205 helps to maintain the working temperature of the friction layer 204, ensuring that it provides a stable friction coefficient within the optimal temperature range, thereby maintaining good braking performance. The heat insulating layer 205 can also play a role in buffering vibration and noise, helping to reduce noise and provide a more comfortable driving experience. The friction layer 204 is used to perform extrusion and friction with the brake disc 1 to brake the vehicle. The connecting groove on the friction layer 204 is used to improve heat dissipation efficiency and reduce noise. When the friction layer 204 rubs against the brake disc 1, a large amount of heat will be generated. If the heat cannot be quickly dissipated, the temperature of the friction layer 204 will continue to rise, thereby affecting the braking performance. The design of the connecting groove helps to take away the heat generated by friction from the surface of the friction layer 204, thereby reducing the working temperature of the friction layer 204 and improving the stability and reliability of the braking performance.

[0035] The connecting grooves also help reduce noise during braking. The gas in the friction layer 204 expands at high temperatures and may form an air cushion between the friction layer 204 and the brake disc 1, causing vibration and noise. The connecting grooves allow these gases to escape more easily, thereby reducing the air cushion effect and reducing the noise level. The connecting grooves of the friction layer 204 on the brake pad steel back 2 can better improve braking efficiency and stability, reduce noise, and help improve vehicle safety.

[0036] The steel back 2 is preferably made of stainless steel metal, and a protective layer is provided on the surface of the steel back 2, and the protective layer is preferably made of rubber. The steel back 2 made of stainless steel metal has excellent corrosion resistance and can resist corrosion under bad weather and road conditions, such as salt water, acid rain and chemicals. The steel back 2 made of stainless steel metal can maintain its mechanical strength and stability at high temperatures, which is suitable for the high temperature environment generated during braking, ensuring stable braking performance. The steel back 2 made of stainless steel metal has a high hardness and can resist wear during braking, thereby extending the service life of the brake device. Compared with traditional steel, the steel back 2 made of stainless steel metal has higher strength, but its weight is lighter, which helps to reduce the overall weight of the vehicle and improve fuel economy. The steel back 2 made of stainless steel metal has good thermal conductivity, can effectively conduct the heat generated by friction to the outside of the brake device, help dissipate heat, and the steel back 2 made of stainless steel metal has excellent fatigue resistance, can withstand repeated stress during braking without fatigue cracks, making the performance of the brake device more reliable and longer in service life, and the steel back 2 made of stainless steel metal is more environmentally friendly and can be recycled after being discarded.

[0037] The protective layer is made of rubber material, which can effectively isolate the high temperature generated by braking, protect the steel back 2 from being directly exposed to high temperature, reduce heat conduction to the steel back 2, and thus protect the stability of the overall structure of the brake pad. The rubber material can prevent moisture from penetrating into the steel back 2, avoid rust problems caused by humidity changes, and extend the service life of the brake pad. The rubber material itself has good shock absorption and sound absorption properties, which can reduce vibration and noise during braking and provide a smoother and quieter driving experience. During the braking process, the steel back 2 will deform to a certain extent due to heat and pressure. The elasticity of the rubber protective layer can help the steel back 2 better adapt to this deformation and maintain braking performance. The rubber protective layer provides a multifunctional protection for the brake pad, which not only improves the durability and reliability of the brake pad, but also helps to improve driving safety and comfort.

[0038] The adhesive layer 206 is preferably made of phenolic resin, and the heat insulating layer 205 is preferably made of ceramic fiber. The adhesive layer 206 is made of phenolic resin with good adhesion, and the heat insulating layer 205 and the friction layer 204 can be firmly bonded to the steel back 2, ensuring that the heat insulating layer 205 and the friction layer 204 will not fall off during the braking process. The adhesive layer 206 made of phenolic resin can maintain stable physical properties at high temperatures, avoiding the high temperature generated during braking causing the adhesive layer 206 of phenolic resin to melt and cause the heat insulating layer 205 and the friction layer 204 to fall off, and the cured adhesive layer 206 of phenolic resin has high mechanical strength, can withstand the pressure and impact during braking, and improve the overall structural stability of the brake pad. The adhesive layer 206 of phenolic resin helps to protect the steel back 2 from wear and tear and prolong the service life of the brake device. The adhesive layer 206 of phenolic resin has good resistance to most chemical substances and can resist corrosive substances that may be encountered on the road surface. The adhesive layer 206 made of phenolic resin has good fluidity and can fully penetrate into the friction material to form a uniform adhesive layer 206. The phenolic resin material can be cured through a simple heat treatment process, which is convenient for large-scale production and processing. Compared with other high-performance adhesives, the cost of phenolic resin material is relatively low, which helps to control the cost of brake device production. After proper treatment, the phenolic resin material can be processed and recycled in a more environmentally friendly manner, reducing the impact on the environment.

[0039] The thermal insulation layer 205 made of ceramic fiber material has low thermal conductivity, which can effectively block the high temperature generated during braking from being transferred to the steel back 2 and other vehicle structures, reducing the thermal impact. The thermal insulation layer 205 made of ceramic fiber material can maintain stable physical and chemical properties in a high temperature environment, and is suitable for the high temperature conditions generated by the braking system. The thermal insulation layer 205 made of ceramic fiber material is not easily susceptible to chemical corrosion, can resist the invasion of a variety of chemical substances, and improve the durability of the braking system. The thermal insulation layer 205 made of ceramic fiber material has a low coefficient of thermal expansion, which means that the volume changes less under temperature changes, which is conducive to maintaining the dimensional stability of the brake pad. The thermal insulation layer 205 made of ceramic fiber material can withstand rapid temperature changes without breaking, which helps to cope with frequent temperature fluctuations during braking. The thermal insulation layer 205 made of ceramic fiber material has natural fire retardant properties, which can improve the safety of the vehicle under special circumstances.

[0040] A cooling layer 207 is fixedly provided on the side wall of the other side of the steel back 2, and a plurality of fixing plates 214 are fixedly provided on the side wall of the cooling layer 207. A second threaded hole is penetrated through the fixing plate 214, and a second bolt 215 is provided in the second threaded hole. The cooling layer 207 cools down the side wall of the steel back 2 through the circulating cooling solution to ensure the performance of the steel back 2 when the temperature rises. The fixing plate 214 is used to fix the cooling layer 207 on the side wall of the steel back 2, and the second bolt 215 is used to fix the fixing plate 214.

[0041] A plurality of communication ports 217 are formed on the surface of the cooling layer 207. A connection plug 216 is fixedly provided on the inner wall of the communication port 217. A moving block 104 is provided on the inner wall of the connection plug 216. The communication port 217 is used to allow the moving block 104 to pass through the cooling layer 207 to push the steel back 2 to move. The connection plug 216 is used to protect the cooling layer 207 and avoid friction between the cooling layer 207 and the moving block 104.

[0042] A cooling device 208 is provided on one side of the cooling layer 207, and a liquid outlet pipe 211 is fixedly provided on the upper end of the cooling device 208. A third through hole is penetrated on one side of the cooling layer 207, and one end of the liquid outlet pipe 211 passes through the third through hole and is fixedly connected to the cooling layer 207. A plurality of liquid outlets 212 in a uniform array are penetrated on the side wall at one end of the liquid outlet pipe 211, and a first liquid pump 209 is fixedly provided on the other end of the liquid outlet pipe 211. A liquid return pipe 213 is fixedly provided on the lower end of the cooling device 208, and a second liquid pump 210 is fixedly provided on one end of the liquid return pipe 213, and the other end of the liquid return pipe 213 is fixedly connected to the lower side wall of the cooling layer 207. The cooling device 208 is used to circulate and cool the solution in the cooling layer 207. The liquid outlet 212 on the liquid outlet pipe 211 is used to transport the solution to various parts of the cooling layer 207 to avoid the solution from being concentrated in the same area. The first liquid pump 209 is used to input the cooling solution into the cooling layer 207. The second liquid pump 210 is used to extract the solution after the operation in the cooling layer 207 through the return pipe 213 and transport it to the cooling device 208 for cooling again.

[0043] The above description is only a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A thorn steel back with a hook-type thorn structure, comprising a brake disc (1), characterized in that: An upper shell (102) is arranged above the brake disc (1), and a side shell (101) is arranged on the side wall of the upper shell (102). A first threaded hole is penetrated through the upper end of the side wall of the side shell (101), and a first bolt (103) is arranged in the first threaded hole. The first bolt (103) passes through the first threaded hole and is fixedly connected to the upper shell (102). A fixing rod (105) is fixedly arranged between the side shells (101) on both sides, and a friction brake part is arranged on the fixing rod (105).

2. The barbed steel back with a hook-type barbed structure according to claim 1, characterized in that: The friction brake part comprises a steel back (2), a plurality of mounting holes (203) are formed through the upper end of the steel back (2), the mounting holes (203) have a square cross section, the fixing rod (105) has a square cross section, and the fixing rod (105) has the same cross section area as the mounting hole (203).

3. The thorn steel back with a hook-type thorn structure according to claim 2, characterized in that: A plurality of evenly arrayed curved thorns (201) are fixedly arranged on a side wall of one side of the steel back (2), a groove (202) is provided at the lower end of the curved thorn (201), the cross section of the side wall of the curved thorn (201) is in a hook shape, and the cross section of the front end of the curved thorn (201) is in a rectangular shape.

4. The thorn steel back with a hook-type thorn structure according to claim 3, characterized in that: The distance between adjacent curved thorns (201) on both sides is greater than or equal to 4 mm, the side wall height of the curved thorn (201) is 1.5 to 3 mm, and the cross section of the groove (202) is square.

5. The thorn steel back with a hook-type thorn structure according to claim 4, characterized in that: An adhesive layer (206) is fixedly provided on the curved thorn (201), a heat insulating layer (205) is fixedly provided on the side wall of the adhesive layer (206), a friction layer (204) is fixedly provided on the side wall of the heat insulating layer (205), and a plurality of connecting grooves are penetrated through the friction layer (204).

6. The barbed steel back with a hook-type barbed structure according to claim 5, characterized in that: The steel back (2) is preferably made of stainless steel metal. A protective layer is provided on the surface of the steel back (2), and the protective layer is preferably made of rubber.

7. The barbed steel back with a hook-type barbed structure according to claim 6, characterized in that: The adhesive layer (206) is preferably made of phenolic resin, and the heat insulation layer (205) is preferably made of ceramic fiber.

8. The barbed steel back with a hook-type barbed structure according to claim 7, characterized in that: A cooling layer (207) is fixedly provided on the side wall of the other side of the steel back (2), and a plurality of fixing plates (214) are fixedly provided on the side wall of the cooling layer (207). A second threaded hole is penetrated through the fixing plate (214), and a second bolt (215) is provided in the second threaded hole.

9. The barbed steel back with a hook-type barbed structure according to claim 8, characterized in that: A plurality of communication ports (217) are formed through the surface of the cooling layer (207), a connection plug (216) is fixedly provided on the inner wall of the communication port (217), and a moving block (104) is provided on the inner wall of the connection plug (216).

10. The barbed steel back with a hook-type barbed structure according to claim 9, characterized in that: A cooling device (208) is provided on one side of the cooling layer 207. A liquid outlet pipe (211) is fixedly provided on the upper end of the cooling device (208). A third through hole is penetrated through one side of the cooling layer (207). One end of the liquid outlet pipe (211) passes through the third through hole and is fixedly connected to the cooling layer (207). A plurality of liquid outlets (212) in a uniform array are penetrated through the side wall of one end of the liquid outlet pipe (211). A first liquid pump (209) is fixedly provided on the other end of the liquid outlet pipe (211). A liquid return pipe (213) is fixedly provided on the lower end of the cooling device (208). A second liquid pump (210) is fixedly provided on one end of the liquid return pipe (213). The other end of the liquid return pipe (213) is fixedly connected to the lower side wall of the cooling layer (207).

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