Motorcycle side plate manufacturing injection mold

Abstract

The utility model relates to injection mold technical field discloses a motorcycle side plate production injection mold, including a motorcycle side plate production injection mold, including upper die and lower die, the upper die bottom fixedly connected with core, the core inside is provided with the ejection assembly, the ejection assembly includes a plurality of top plates, the top plate top all are fixedly connected with buffer disc spring, buffer disc spring top all are fixedly connected with the connecting plate, the connecting plate top all are provided with power component, power component output all are fixedly connected with the push rod, the push rod outer wall all are equipped with the extension spring. In the utility model, the connecting plate and buffer disc spring are moved with the push rod of hydraulic ware and top plate, and make the extension spring force stretch, and the top plate will be shaped side plate and lift to take and hold for the staff, reach the effect that the carbon fiber surface damage caused by top plate is avoided, solve the problem that traditional stripping ejector pin stress concentration leads to product damage, improve the product surface quality.

Description

Technical Field

[0001] This utility model relates to the field of injection mold technology, and in particular to an injection mold for manufacturing motorcycle side panels. Background Technology

[0002] In the field of motorcycle parts manufacturing, carbon fiber materials have gradually become the ideal material for structural parts such as motorcycle side panels due to their lightweight, high strength and corrosion resistance. Using injection molds to form carbon fiber side panels can achieve efficient mass production of complex geometries. Compared with traditional hand lay-up molding or hot pressing molding processes, it has significant advantages such as short production cycle, high design freedom and suitability for mass production.

[0003] Existing motorcycle side panel injection molds typically employ a traditional integral cavity structure, with the cavity and core assembled through a fixed splicing method. The runner system is mostly a fixed-section cold runner design, and the gate type is mainly a common submarine gate or side gate. The demolding mechanism generally adopts a rigid ejector direct ejection structure, with the ejector contacting the product made of hard metal. The ejection force is provided by the hydraulic system of the injection molding machine. The cooling system is achieved by opening fixed water channels inside the cavity and core. The connection between the water pipe and the mold is mostly through threaded interfaces or flange connections, which need to be tightened with tools to achieve the circulation of the cooling medium.

[0004] However, when the demolding mechanism of traditional injection molds uses a rigid ejector pin for direct ejection, the stress concentration phenomenon during the ejection process is significant because the ejector pin is in hard contact with the surface of the carbon fiber side plate. This easily leads to scratches, microcracks, or even local fractures on the product surface. The risk of damage is even higher for side plates with complex curved surfaces or thin-walled structures. This not only increases the product defect rate and affects the appearance quality and mechanical properties, but also requires additional surface repair processes, increasing production costs. Therefore, an injection mold for manufacturing motorcycle side plates is proposed to solve the above problems. Utility Model Content

[0005] To overcome the above shortcomings, this utility model provides an injection mold for manufacturing motorcycle side panels, which aims to improve the problem of stress concentration in the ejector pins of the prior art, which leads to product damage.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A motorcycle side panel injection mold includes an upper mold and a lower mold. The bottom of the upper mold is fixedly connected to a core, and a cooling component is provided inside the upper mold. The top of the outer wall of the lower mold has a cavity, and an ejection component is provided inside the core.

[0008] The ejection assembly includes multiple top plates arranged in a rectangular array inside the core. The outer walls of the top plates are slidably connected to the inside of the core. Each top plate has a buffer disc spring fixedly connected to its top, and each buffer disc spring has a connecting plate fixedly connected to its top. Each connecting plate has a power assembly on its top, and each power assembly has a push rod fixedly connected to its output end. The bottom of each push rod is fixedly connected to the top of the connecting plate, and each push rod has a tension spring sleeved on its outer wall. One end of each tension spring is fixedly connected to the top of the connecting plate, and the other end of each tension spring is fixedly connected to the inside of the core.

[0009] As a further description of the above technical solution:

[0010] The power assembly includes multiple hydraulic units, which are arranged in a rectangular array inside the upper mold. Each hydraulic unit has a fixed bracket fixedly connected to its outer wall, and the bottom of each fixed bracket is fixedly connected to the bottom of the inner wall of the upper mold. The output end of each hydraulic unit is fixedly connected to the top of the connecting plate.

[0011] As a further description of the above technical solution:

[0012] A base is fixedly connected to the center of the top of the upper mold, and positioning rods are fixedly connected to the four corners of the bottom of the upper mold. Injection ports are fixedly connected to both sides of the outer wall of the lower mold. Multiple positioning holes are opened on the top of the outer wall of the lower mold, and the positions of the positioning holes are consistent with the positions of the positioning rods.

[0013] As a further description of the above technical solution:

[0014] The cooling assembly includes multiple water-cooling pipes arranged in an array inside the upper mold. The outer walls of the water-cooling pipes are fixedly connected to the inside of the upper mold, and controllers are fixedly connected to both sides of the outer wall of the upper mold.

[0015] As a further description of the above technical solution:

[0016] Each controller sidewall is fixedly connected to a connecting seat and a connecting pipe. The outer wall of one side of each connecting seat is fixedly connected to the inner wall of the connecting pipe. Each sidewall of each connecting seat is fixedly connected to a sealing ring. Multiple limiting balls are slidably connected inside each connecting pipe. The limiting balls are circumferentially distributed, and the outer walls of the limiting balls are slidably connected inside the connecting pipe.

[0017] As a further description of the above technical solution:

[0018] Each connecting pipe has a sleeve slidably connected to its outer wall, and each sleeve has a limit ring fixedly connected to its inner wall.

[0019] As a further description of the above technical solution:

[0020] Each connecting pipe is fitted with a limiting spring on its outer wall. One end of each limiting spring is fixedly connected to the side wall of the limiting ring, and the other end of each limiting spring is fixedly connected to the side wall of the connecting seat.

[0021] As a further description of the above technical solution:

[0022] Water pipes are slidably connected to the inner wall of each connecting pipe, and a limit groove is formed on one side of the outer wall of each water pipe.

[0023] This utility model has the following beneficial effects:

[0024] 1. In this utility model, the hydraulic device pushes the connecting plate downward through the push rod, and at the same time, the tension spring is stretched. The buffer disc spring at the bottom and the top plate move accordingly. When the top plate is squeezed by the side plate, the buffer disc spring deforms, lifting the molded motorcycle side plate so that the workers can pick it up. This achieves the effect of avoiding scratches or micro-cracks on the carbon fiber surface caused by the top plate when ejecting. It solves the problem of stress concentration of traditional demolding ejector rods, which leads to product damage and improves the surface quality of the product.

[0025] 2. In this utility model, the operator slides the sleeve to compress the limiting spring and loosen the limiting ball, inserts one end of the water pipe into the limiting ball, and makes the side wall of the water pipe fit against the sealing ring of the side wall of the connecting seat. Then, the sleeve is released, and the sleeve and the limiting ring are reset under the action of the limiting spring. The limiting ball slides into the limiting groove to complete the water pipe limiting, achieving the effect of quick water pipe connection. This solves the problem of cumbersome and time-consuming connection of the liquid inlet water pipe of the traditional cooling device and improves the installation efficiency of the mold cooling system. Attached Figure Description

[0026] Figure 1 A perspective view of an injection mold for manufacturing a motorcycle side panel according to this utility model;

[0027] Figure 2 This is a schematic diagram of the upper mold structure for an injection mold used to manufacture a motorcycle side panel, as proposed in this utility model.

[0028] Figure 3 This is a schematic diagram of the core structure of an injection mold for manufacturing a motorcycle side panel according to the present invention.

[0029] Figure 4 This is a schematic diagram of the top plate structure of an injection mold for manufacturing a motorcycle side panel according to the present invention.

[0030] Figure 5 Exploded view of the result of the connecting seat for the injection mold of the motorcycle side panel proposed in this utility model;

[0031] Figure 6 This is a schematic diagram of the sleeve structure for an injection mold used to manufacture a motorcycle side panel, as proposed in this utility model.

[0032] Legend:

[0033] 1. Upper mold; 2. Lower mold; 3. Core; 4. Cavity; 5. Injection port; 6. Positioning rod; 7. Positioning hole; 8. Base; 9. Hydraulic unit; 10. Fixed bracket; 11. Push rod; 12. Tension spring; 13. Connecting plate; 14. Buffer disc spring; 15. Top plate; 16. Water cooling pipeline; 17. Controller; 18. Connecting seat; 19. Sealing ring; 20. Connecting pipe; 21. Limiting ball; 22. Limiting spring; 23. Sleeve; 24. Limiting ring; 25. Water pipe; 26. Limiting groove. Detailed Implementation

[0034] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0035] Reference Figure 1 - Figure 4 This utility model provides an embodiment of an injection mold for manufacturing a motorcycle side panel, including an upper mold 1 and a lower mold 2. Both the upper mold 1 and the lower mold 2 are made of high-strength mold steel, which has good wear resistance and thermal strength. A core 3 is fixedly connected to the bottom of the upper mold 1. The core 3 is used to form the internal structure of the motorcycle side panel and is made of high-hardness alloy steel. The surface is polished to ensure a smooth molding surface. A cooling component is provided inside the upper mold 1 to cool and solidify the raw material after injection. A cavity 4 is opened on the top of the outer wall of the lower mold 2. The cavity 4 and the core 3 cooperate to form the molding space of the motorcycle side panel. An ejection component is provided inside the core 3.

[0036] The ejection assembly includes multiple top plates 15, each made of wear-resistant and high-temperature-resistant rubber, used to eject the molded motorcycle side panels. The top plates 15 are arranged in a rectangular array inside the core 3. The outer walls of the top plates 15 are slidably connected to the core 3. Each top plate 15 has a fixedly connected buffer disc spring 14 made of spring steel, providing good cushioning performance. Each buffer disc spring 14 has a fixedly connected connecting plate 13 made of metal, used to transmit the thrust of the power assembly. Each connecting plate 13 has a power assembly on top, and each power assembly output end is fixedly connected to a push rod 11, used to transmit power to the connecting plate 13. The bottom is fixedly connected to the top of the connecting plate 13. Each push rod 11 has a tension spring 12 fitted on its outer wall. The tension spring 12 is made of spring steel and is used to drive the push rod 11 back to its original position after ejection. One end of each tension spring 12 is fixedly connected to the top of the connecting plate 13, and the other end is fixedly connected to the inside of the core 3. The power assembly includes multiple hydraulic actuators 9. Each hydraulic actuator 9 is a device that converts hydraulic energy into mechanical energy. It consists of a hydraulic cylinder and a hydraulic control system, which is existing technology and will not be described in detail here. The hydraulic actuators 9 are arranged in a rectangular array inside the upper mold 1. Each hydraulic actuator 9 has a fixed bracket 10 fixedly connected to its outer wall. The fixed bracket 10 is made of metal. The bottom of each of the 10 components is fixedly connected to the bottom of the inner wall of the upper mold 1 by bolts to fix the position of the hydraulic device 9. The output end of the hydraulic device 9 is fixedly connected to the top of the connecting plate 13 by coupling to provide power for the ejection action. A base 8 is fixedly connected to the center of the top of the upper mold 1 to connect the pressing device and transmit the power for pressing down and rising. Positioning rods 6, made of metal, are fixedly connected to the four corners of the bottom of the upper mold 1 to cooperate with the positioning holes 7 of the lower mold 2 to ensure accurate positioning between the molds. Injection ports 5, made of metal, are fixedly connected to both sides of the outer wall of the lower mold 2 to connect the injection pipes and inject molten metal into the mold. Carbon fiber raw material is injected into cavity 4. Multiple positioning holes 7 are opened on the top of the outer wall of the lower mold 2. The positioning holes 7 are in the same position as the positioning rod 6 and are used to cooperate with the positioning rod 6 to achieve mold positioning. The cooling component includes multiple water cooling pipes 16. The water cooling pipes 16 are made of copper pipes and are used to pass cooling water to cool the raw material after injection molding. The water cooling pipes 16 are distributed in an array inside the upper mold 1. The outer wall of the water cooling pipes 16 is fixedly connected to the inside of the upper mold 1. Controllers 17 are fixedly connected to both sides of the outer wall of the upper mold 1. The controllers 17 consist of a metal shell and internal electronic components and are used to control the operation of the water cooling system and hydraulic device 9. This is existing technology and will not be described in detail here.

[0037] Specifically, when using this motorcycle side panel to make an injection mold, the worker first connects the connecting end of the pressing device to the base 8 using bolts or other connectors. Next, the outlet of the injection pipe is connected to the injection port 5 to ensure the raw material can be smoothly injected into the mold. Then, one end of the water pipe 25 is connected to the water inlet of the controller 17, and the other end is connected to an external water source. After preparation, the worker starts the pressing device, which drives the upper mold 1 and the core 3 downwards, gradually pressing them into the cavity 4 at the top of the lower mold 2. Simultaneously, the upper mold... The positioning rods 6 at the four corners of the bottom of mold 1 also move downwards and insert into the positioning holes 7 at the top of the outer wall of the lower mold 2, thereby completing the extrusion molding of the internal carbon fiber material. After the material is extruded, the water cooling system inside the upper mold 1 starts to work. The controller 17 controls the cooling water to flow from the water pipe 25 into the water cooling pipe 16. The cooling water circulates from the inlet to the outlet inside the water cooling pipe 16, absorbing the heat around the core 3 and the cavity 4, so that the carbon fiber motorcycle side panel is cooled and molded. After cooling is completed, the pressing device switches to the upward motion mold. This movement causes the upper mold 1 to move upwards, and the core 3 to exit the cavity 4. Subsequently, the output ends of multiple hydraulic actuators 9 inside the upper mold 1 push the push rod 11 downwards, causing the connecting plate 13 to move downwards as well. This displacement causes the tension spring 12 to be subjected to tensile force, gradually stretching and storing elastic potential energy. At the same time, the buffer disc spring 14 at the bottom of the connecting plate 13 and the top plate 15 also move downwards. When the top plate 15 is subjected to the reaction force of the side plate, the buffer disc spring 14 undergoes a certain degree of elastic deformation. Through the compression of the buffer disc spring 14, the top plate 15 is reduced. The impact force of plate 15 on the side plate prevents the top plate 15 from causing scratches or micro-cracks on the carbon fiber surface. As the top plate 15 continues to move, the molded motorcycle side plate is gradually lifted and separated from the core 3 for easy handling by the staff. After the side plate is ejected, the output end of the hydraulic device 9 retracts, pulling the push rod 11 and the connecting plate 13 to reset upwards. The tension spring 12 releases the stored elastic potential energy, pulling the connecting plate 13 and the push rod 11 to move upwards. The buffer disc spring 14 also gradually returns to its original state, driving the top plate 15 back to the initial position, completing one injection and ejection cycle.

[0038] Reference Figure 5 and Figure 6The controller 17 has connecting seats 18 and connecting pipes 20 fixedly connected to its side walls. The controller 17 serves as the control component of the mold cooling system, forming a quick-connect structure for the cooling pipes together with the connecting seats 18 and connecting pipes 20. The connecting seats 18 are made of brass, possessing good wear resistance and sealing properties, and are used to support the sealing rings 19 and provide a connection interface for the water pipes 25. The connecting pipes 20 are made of stainless steel, with a smooth inner wall formed by machining, used to accommodate the limiting balls 21 and guide the water pipes 25 into place. One outer wall of the connecting seats 18 is fixedly connected to the inner wall of the connecting pipes 20 by welding. Sealing rings 19 are fixedly connected to the side walls of the connecting seats 18 by inserting into slots. The sealing rings 19 are made of rubber, possessing elasticity, and are used to fill the gap between the water pipes 25 and the connecting seats 18 to prevent cooling water leakage. Multiple limiting balls 21 are slidably connected inside the connecting pipes 20, and the limiting balls 21 are used to engage the water pipes. The limiting groove 26 of the water pipe 25 achieves mechanical locking. The limiting balls 21 are distributed in a circular shape, and the outer walls of the limiting balls 21 are slidably connected to the inside of the connecting pipe 20. The outer walls of the connecting pipe 20 are slidably connected to sleeves 23, which are made of engineering plastic and have anti-slip textures on their outer walls. The inner walls of the sleeves 23 are fixedly connected to limiting rings 24, which are used to squeeze the limiting balls 21 and make them lock into the limiting groove 26. The outer walls of the connecting pipe 20 are all fitted with limiting springs 22. The limiting spring 22 is made of spring steel. One end of the limiting spring 22 is fixedly connected to the side wall of the limiting ring 24, and the other end of the limiting spring 22 is fixedly connected to the side wall of the connecting seat 18. It is used to provide a restoring force to push the sleeve 23 and the limiting ring 24 back to their original positions. The inner wall of the connecting pipe 20 is slidably connected to the water pipe 25. The outer wall of one side of the water pipe 25 is provided with a limiting groove 26. The position of the limiting groove 26 corresponds to the limiting ball 21 and is used to cooperate with the limiting ball 21 to achieve connection.

[0039] Specifically, when connecting the water pipe 25, the worker first holds the sleeve 23 with their hand, using the connecting pipe 20 as a fulcrum, and pulls the sleeve 23. Under the pulling force of the worker's hand, the sleeve 23 slides outward along the outer wall of the connecting pipe 20, causing the inner wall's limiting ring 24 to move synchronously. When the limiting ring 24 moves away from the connecting seat 18, the limiting ball 21, which was originally squeezed by the limiting ring 24, loses lateral pressure and slides freely inside the connecting pipe 20, becoming loose. Subsequently, the worker aligns one end of the water pipe 25 with the inlet of the connecting pipe 20, and inserts it in a straight line towards the connecting seat 18, using the connecting pipe 20 as a reference. During the insertion of the water pipe 25, its outer wall pushes the limiting ball 21 to slide towards the inner wall of the connecting pipe 20. At the same time, the side wall of the water pipe 25 gradually contacts the sealing ring 19 on the side wall of the connecting seat 18. The sealing ring 19... Under compression, the tube 25 undergoes elastic deformation, tightly fitting against the outer wall of the water pipe 25 to form a seal. When the water pipe 25 is inserted into place, the limiting groove 26 on its outer wall moves to the corresponding position of the limiting ball 21. At this time, the operator releases their hand holding the sleeve 23, and the elastic potential energy stored in the limiting spring 22 due to previous compression is released, pushing the sleeve 23 and the limiting ring 24 to reset towards the connecting seat 18. During the reset process, the inner wall of the limiting ring 24 compresses the limiting ball 21, causing it to embed into the limiting groove 26 and tightly cooperate with the groove wall, preventing the water pipe 25 from moving axially and completing the mechanical locking. Through the above operations, the water pipe 25 is quickly fixed in the connecting pipe 20, the sealing ring 19 ensures the sealing of the cooling water circuit, and the limiting ball 21 and the limiting groove 26 achieve a reliable mechanical connection, achieving the effect of quickly connecting the water pipe 25.

[0040] Working principle: When using this motorcycle side panel to make an injection mold, the operator first connects the pressing device to the base 8, then connects the injection pipe to the injection port 5, and then connects the water pipe 25 to the controller 17. The operator first slides the sleeve 23, causing the limiting spring 22 to be compressed and the limiting ball 21 to loosen. Then, one end of the water pipe 25 is inserted into the limiting ball 21, so that the side wall of the water pipe 25 fits against the sealing ring 19 on the side wall of the connecting seat 18. Then, the operator releases the sleeve 23, and under the action of the limiting spring 22, pushes the sleeve 23 and the limiting ring 24 back to their original positions, squeezing the limiting ball 21 into the limiting groove 26, thereby completing the limiting of the water pipe 25 and achieving the effect of quickly connecting the water pipe 25.

[0041] After preparation, the pressing device drives the upper mold 1 to descend, pressing the core 3 into the cavity 4. At the same time, the positioning rod 6 at its bottom is also inserted into the positioning hole 7, thus completing the extrusion molding of the carbon fiber material inside. Subsequently, the water cooling system inside the upper mold 1 works to cool and mold the carbon fiber motorcycle side panel. After cooling, the upper mold 1 moves upward under the drive of the pressing device. Then, multiple hydraulic devices 9 inside the upper mold 1 push the push rod 11 downward. The displacement of the push rod 11 causes the connecting plate 13 to move downward, and at the same time, the tension spring 12 is stretched. As the connecting plate 13 moves, the buffer disc spring 14 at its bottom and the top plate 15 also move. When the top plate 15 is squeezed by the side panel, the buffer disc spring 14 will deform to a certain extent, thus lifting the molded motorcycle side panel for easy handling by the staff. This achieves the effect of preventing the top plate 15 from causing scratches or micro-cracks on the carbon fiber surface when ejecting.

[0042] Finally, it should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. An injection mold for manufacturing a motorcycle side panel, comprising an upper mold (1) and a lower mold (2), characterized in that: The upper mold (1) is fixedly connected to the bottom of the mold core (3), the upper mold (1) is provided with a cooling component, the lower mold (2) has a cavity (4) on the top of the outer wall, and the core (3) is provided with an ejection component. The ejection assembly includes multiple top plates (15), which are arranged in a rectangular array inside the core (3). The outer walls of the top plates (15) are slidably connected to the inside of the core (3). A buffer disc spring (14) is fixedly connected to the top of each top plate (15). A connecting plate (13) is fixedly connected to the top of each buffer disc spring (14). A power assembly is provided on the top of each connecting plate (13). A push rod (11) is fixedly connected to the output end of each power assembly. The bottom of each push rod (11) is fixedly connected to the top of the connecting plate (13). A tension spring (12) is sleeved on the outer wall of each push rod (11). One end of each tension spring (12) is fixedly connected to the top of the connecting plate (13), and the other end of each tension spring (12) is fixedly connected to the inside of the core (3).

2. The injection mold for manufacturing a motorcycle side panel according to claim 1, characterized in that: The power assembly includes multiple hydraulic units (9), which are arranged in a rectangular array inside the upper mold (1). Each hydraulic unit (9) has a fixed bracket (10) fixedly connected to its outer wall. The bottom of each fixed bracket (10) is fixedly connected to the bottom of the inner wall of the upper mold (1). The output end of each hydraulic unit (9) is fixedly connected to the top of the connecting plate (13).

3. The injection mold for manufacturing a motorcycle side panel according to claim 1, characterized in that: The upper mold (1) is fixedly connected to the base (8) at the top center position. The upper mold (1) is fixedly connected to the four corners of the bottom of the four corners with positioning rods (6). The lower mold (2) is fixedly connected to the injection port (5) on both sides of the outer wall. The lower mold (2) has multiple positioning holes (7) on the top of the outer wall. The position of the positioning holes (7) is consistent with the position of the positioning rods (6).

4. The injection mold for manufacturing a motorcycle side panel according to claim 1, characterized in that: The cooling assembly includes multiple water-cooled pipes (16), which are arranged in an array inside the upper mold (1). The outer walls of the water-cooled pipes (16) are fixedly connected to the inside of the upper mold (1), and controllers (17) are fixedly connected to both sides of the outer wall of the upper mold (1).

5. The injection mold for manufacturing a motorcycle side panel according to claim 4, characterized in that: The controller (17) is fixedly connected to a connecting seat (18) and a connecting pipe (20) on its side wall. The outer wall of one side of the connecting seat (18) is fixedly connected to the inner wall of the connecting pipe (20). The side wall of the connecting seat (18) is fixedly connected to a sealing ring (19). Multiple limiting balls (21) are slidably connected inside the connecting pipe (20). The limiting balls (21) are distributed in a circular shape. The outer wall of the limiting balls (21) is slidably connected inside the connecting pipe (20).

6. The injection mold for manufacturing a motorcycle side panel according to claim 5, characterized in that: Each of the connecting pipes (20) has a sleeve (23) slidably connected to its outer wall, and each of the sleeves (23) has a limit ring (24) fixedly connected to its inner wall.

7. The injection mold for manufacturing a motorcycle side panel according to claim 6, characterized in that: Each connecting pipe (20) is fitted with a limiting spring (22) on its outer wall. One end of each limiting spring (22) is fixedly connected to the side wall of the limiting ring (24), and the other end of each limiting spring (22) is fixedly connected to the side wall of the connecting seat (18).

8. The injection mold for manufacturing a motorcycle side panel according to claim 7, characterized in that: The inner wall of each connecting pipe (20) is slidably connected to a water pipe (25), and a limit groove (26) is provided on one side of the outer wall of each water pipe (25).

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