Rapid cooling equipment for injection molding of plastic shell of battery pack

Abstract

The invention provides rapid cooling equipment for injection molding of a plastic shell of a battery pack. The battery pack plastic shell injection molding rapid cooling equipment comprises a transverse support, the upper side of the transverse support is fixedly connected with an airflow generation device and a heat dissipation structure, the heat dissipation structure is located on the upper side of the airflow generation device, the heat dissipation structure comprises an active heat dissipation assembly, a passive heat dissipation assembly and an auxiliary assembly, and the auxiliary assembly comprises a rotating shaft, a limiting rotating wheel and a bent support. According to the rapid cooling equipment for injection molding of the plastic shell of the battery pack, the cooling effect of the plastic shell of the battery pack in the injection molding process is effectively improved through combination of the airflow generation device and the heat dissipation structure, and the situation that stress generated inside is not uniform is avoided, so that the overall quality and the use performance of the plastic shell are improved; and by arranging auxiliary assemblies such as the longitudinal supports, the elastic foot pads and the bent supports, the stability of the equipment is enhanced, and sliding or instability caused by vibration is prevented.

Description

Technical Field

[0001] The invention relates to the technical field of injection molding rapid cooling, and in particular to a battery pack plastic shell injection molding rapid cooling device. Background Art

[0002] A battery pack plastic shell injection molding rapid cooling equipment is mainly composed of an injection molding machine, a mold system, a cooling system, a control system, and a heating and cooling adjustment device. The injection molding machine is responsible for injecting the melted plastic into the mold. The mold system is designed according to the shape of the battery pack shell to ensure the accurate molding of the shell. The cooling system quickly reduces the mold temperature through multiple cooling channels set in the mold, accelerates the cooling of the plastic, and shortens the injection molding cycle. Coolant (such as water) or gas circulates through the cooling system to achieve a cooling effect, and the temperature control device ensures precise control of the cooling process. The entire system is regulated by the control system, and key parameters such as temperature and pressure are monitored in real time to ensure the stability and consistency of the injection molding process. The heating and cooling adjustment device helps control the appropriate temperature of the mold to ensure a balance between material melting and cooling during the injection molding process.

[0003] Although this equipment has advantages in improving production efficiency and accelerating cooling speed, it still has some defects. The design of the cooling system may lead to uneven cooling, especially when the layout of the cooling channel is unreasonable, which may cause uneven stress inside the plastic shell and affect product quality. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides a battery pack plastic shell injection molding rapid cooling device, which solves the problem of uneven cooling caused by the design of the cooling system, especially when the layout of the cooling channel is unreasonable, which may cause uneven stress inside the plastic shell.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: A battery pack plastic shell injection molding rapid cooling device, comprising:

[0006] A transverse bracket, an upper side of which is fixedly connected with an airflow generating device;

[0007] A heat dissipation structure, which is located on the upper side of the airflow generating device, and the heat dissipation structure includes an active heat dissipation component and a passive heat dissipation component;

[0008] The auxiliary component includes a rotating shaft, a limiting rotating wheel and a bending bracket.

[0009] Preferably, the lower side of the transverse bracket is fixedly connected to the longitudinal bracket, and the lower side of the longitudinal bracket is fixedly connected to the lower elastic foot pad to avoid sliding caused by vibration.

[0010] Preferably: the airflow generating device includes a horizontal support plate, a connecting rod, fan blades and a motor, the side surface of the horizontal support plate is fixedly connected to the connecting rod, the end of the connecting rod away from the horizontal support plate is fixedly connected to the motor, and the output end of the motor is fixedly connected to the fan blades.

[0011] Preferably: the passive heat dissipation component includes a connecting piece, a connecting ring, a heat pipe, a blade connecting rod and a heat conducting plate, the heat conducting plate is fixedly connected to the horizontal support plate, a gap is formed between the heat conducting plates, the side surface of the heat conducting plate is fixedly connected to the connecting ring, the side of the connecting ring away from the heat conducting plate is fixedly connected to the heat conducting pipe, the end away from the connecting ring is fixedly connected to the heat conducting pipe, and the end of the heat conducting pipe away from the connecting ring is fixedly connected to the connecting piece.

[0012] Preferably: the active heat dissipation component includes a blade connecting rod, a lateral heat dissipation rod, an oblique ventilation hole, a lateral air hole and a rotating device, the blade connecting rod is fixedly connected to the lateral heat dissipation rod, the oblique ventilation hole is located on the blade connecting rod, the lateral air hole is located on the lateral heat dissipation rod, and the oblique ventilation holes are all inclined clockwise.

[0013] Preferably, the rotating device comprises a rotating disk, a heat-conducting ring, a bearing and a gap, the lower side of the rotating disk is fixedly connected to the heat-conducting ring, the bearing is fixedly connected to the upper side of the rotating disk, and a gap is formed between the bearing and the heat-conducting ring.

[0014] Preferably, the bearing is fixedly connected to the connecting piece.

[0015] Preferably, the bending bracket is fixedly connected to the blade connecting rod, the rotating shaft is fixedly connected to the bending bracket, and the limiting rotating wheel is rotatably connected to the outer side of the rotating shaft.

[0016] The present invention provides a battery pack plastic shell injection molding rapid cooling device. It has the following beneficial effects:

[0017] The battery pack plastic shell injection rapid cooling equipment utilizes the combination of an airflow generating device and a heat dissipation structure to effectively improve the cooling effect of the battery pack plastic shell during the injection molding process, avoiding the generation of uneven stress inside, thereby improving the overall quality and performance of the plastic shell. By providing auxiliary components such as longitudinal brackets, elastic foot pads, and bent brackets, the stability of the equipment is enhanced, and sliding or instability caused by vibration is prevented. The rotating device and the finely designed heat dissipation components enable the equipment to maintain a good heat dissipation effect and a stable working state during long-term operation, thereby improving the reliability and service life of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0019] Figure 2 It is a partial structural schematic diagram of the present invention;

[0020] Figure 3 It is a schematic diagram of the structure of the airflow generating device of the present invention;

[0021] Figure 4 It is a schematic diagram of the heat dissipation structure of the present invention;

[0022] Figure 5 For the present invention Figure 4 A schematic diagram of the structure enlargement in the middle;

[0023] Figure 6 For the present invention Figure 1 A magnified schematic diagram of the structure at B in the middle;

[0024] Figure 7 It is a schematic diagram of the structure of the rotating device of the present invention.

[0025] Among them, 1. horizontal bracket; 2. longitudinal bracket; 3. lower elastic foot pad; 4. horizontal support plate; 5. connecting rod; 6. fan blade; 7. motor; 8. heat conductive sheet; 9. gap; 10. blade connecting rod; 11. rotating shaft; 12. limit wheel; 13. oblique ventilation hole; 14. lateral heat dissipation rod; 15. heat pipe; 16. connecting piece; 17. rotating device; 18. rotating disk; 19. heat conductive ring; 20. bearing; 21. gap; 22. connecting ring; 23. lateral air hole; 24. bending bracket. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] Embodiment 1:

[0028] like Figure 1-7 As shown, an embodiment of the present invention provides a battery pack plastic shell injection molding rapid cooling device, including a transverse bracket 1, an airflow generating device is fixedly connected to the upper side of the transverse bracket 1, a longitudinal bracket 2 is fixedly connected to the lower side of the transverse bracket 1, and a lower elastic foot pad 3 is fixedly connected to the lower side of the longitudinal bracket 2 to avoid sliding caused by vibration. The airflow generating device includes a horizontal support plate 4, a connecting rod 5, a fan blade 6 and a motor 7. The side surface of the horizontal support plate 4 is fixedly connected to the connecting rod 5, and one end of the connecting rod 5 away from the horizontal support plate 4 is fixedly connected to the motor 7, and the output end of the motor 7 is fixedly connected to the fan blade 6;

[0029] A heat dissipation structure, which is located on the upper side of the airflow generating device, and the heat dissipation structure includes an active heat dissipation component and a passive heat dissipation component;

[0030] The auxiliary component includes a rotating shaft 11 , a limiting rotating wheel 12 and a bending bracket 24 .

[0031] Embodiment 1 uses a finely designed airflow generating device, including a horizontal support plate 4, a connecting rod 5, a fan blade 6 and a motor 7 and auxiliary components such as a rotating shaft 11, a limiting wheel 12, and a bending bracket 24, to effectively improve the uniformity and stability of cooling during the injection molding of the plastic shell of the battery pack. Specifically, the airflow generating device ensures the uniform distribution of the airflow through the combination of the horizontal support plate 4, the connecting rod 5, the fan blade 6 and the motor 7, thereby improving the cooling effect and reducing the problem of uneven stress caused by uneven cooling. In addition, the provision of the longitudinal bracket 2 and the lower elastic foot pad 3 enhances the stability of the equipment, effectively avoids the sliding problem caused by vibration, and thus improves the working reliability and service life of the equipment.

[0032] Embodiment 2:

[0033] like Figure 1-7 As shown, an embodiment of the present invention provides a battery pack plastic shell injection molding rapid cooling device, including a transverse bracket 1, and an airflow generating device is fixedly connected to the upper side of the transverse bracket 1;

[0034] The heat dissipation structure is located on the upper side of the airflow generating device. The heat dissipation structure includes an active heat dissipation component and a passive heat dissipation component. The passive heat dissipation component includes a connector 16, a connecting ring 22, a heat pipe 15, a blade connecting rod 10 and a heat conductive sheet 8. The heat conductive sheet 8 is fixedly connected to the horizontal support plate 4. A gap 9 is formed between the heat conductive sheets 8. The side surface of the heat conductive sheet 8 is fixedly connected to the connecting ring 22. The side of the connecting ring 22 away from the heat conductive sheet 8 is fixedly connected to the heat conductive pipe 15. The end away from the connecting ring 22 is fixedly connected to the heat conductive pipe 15. The end of the heat conductive pipe 15 away from the connecting ring 22 is fixedly connected to the connector 16. The active heat dissipation component includes a blade connecting rod 10. The rod 10, the lateral heat dissipation rod 14, the oblique ventilation holes 13, the lateral air holes 23 and the rotating device 17, the blade connecting rod 10 is fixedly connected to the lateral heat dissipation rod 14, the oblique ventilation holes 13 are located on the blade connecting rod 10, the lateral air holes 23 are located on the lateral heat dissipation rod 14, the oblique ventilation holes 13 are all inclined clockwise, the rotating device 17 includes a rotating disk 18, a heat conducting ring 19, a bearing 20 and a gap 21, the lower side of the rotating disk 18 is fixedly connected to the heat conducting ring 19, the bearing 20 is fixedly connected to the upper side of the rotating disk 18, a gap 21 is formed between the bearing 20 and the heat conducting ring 19, and the bearing 20 is fixedly connected to the connecting member 16;

[0035] The auxiliary component includes a rotating shaft 11 , a limiting rotating wheel 12 and a bending bracket 24 .

[0036] Embodiment 2 optimizes the cooling efficiency through the heat dissipation structure, especially the active heat dissipation component including the blade connecting rod 10, the lateral heat dissipation rod 14, the oblique ventilation hole 13, the lateral air hole 23 and the rotating device 17 and the passive heat dissipation component including the connecting member 16, the connecting ring 22, the heat pipe 15, the blade connecting rod 10 and the heat conducting plate 8, which further improves the heat dissipation performance of the device. The passive heat dissipation component adopts the design of the heat conducting plate 8 and the heat conducting pipe 15 to enhance the heat conduction effect, while the active heat dissipation component improves the speed of the airflow through the heat sink through the configuration of the blade connecting rod 10 and the lateral heat dissipation rod 14, further accelerating the heat dissipation. The design of the rotating device 17 increases the flexibility and efficiency of the heat dissipation system, thereby effectively avoiding uneven cooling and overheating of the equipment. In addition, the design of the bending bracket 24 and the limit rotating wheel 12 enhances the operational stability of the equipment and reduces the wear and failure rate of mechanical components.

[0037] Embodiment three:

[0038] like Figure 1-7 As shown, an embodiment of the present invention provides a battery pack plastic shell injection molding rapid cooling device, including a transverse bracket 1, and an airflow generating device is fixedly connected to the upper side of the transverse bracket 1;

[0039] A heat dissipation structure, which is located on the upper side of the airflow generating device, and the heat dissipation structure includes an active heat dissipation component and a passive heat dissipation component;

[0040] The auxiliary component includes a rotating shaft 11, a limiting rotating wheel 12 and a bending bracket 24. The bending bracket 24 is fixedly connected to the blade connecting rod 10, the rotating shaft 11 is fixedly connected to the bending bracket 24, and the limiting rotating wheel 12 is rotatably connected to the outer side of the rotating shaft 11.

[0041] Embodiment 3 further enhances the cooling effect and structural stability of the equipment. Its unique fixed connection between the bent bracket 24 and the blade connecting rod 10 improves the fixation of the heat dissipation component and enhances the overall heat dissipation efficiency of the cooling system. The design of the rotating shaft 11 and the limiting rotating wheel 12 improves the mechanical stability of the equipment, reduces the friction and loss between the components, and ensures the stability of the equipment under long-term operation. In addition, the use of the bent bracket 24 optimizes the spatial layout of the heat dissipation system, making the cooling device more compact and efficient. On the whole, Embodiment 3 improves the durability and heat dissipation effect of the equipment through meticulous design, and provides a more reliable solution for the injection molding of the plastic shell of the battery pack.

[0042] Embodiment 4: Experimental embodiment

[0043] In order to verify the cooling uniformity of this technical solution, a heat conduction and fluid dynamics model is established to simulate the cooling effect of the equipment on the plastic shell of the battery pack in actual work, especially the uniform distribution of airflow and heat conduction. The following is an example based on numerical simulation, which verifies the advantages of this technical solution by comparing the temperature distribution under different cooling schemes.

[0044] Model settings

[0045] Model Type:

[0046] Heat conduction model: used to simulate the heat conduction process of plastic shell.

[0047] Fluid dynamics model (CFD): used to simulate air flow distribution and its effect on heat removal.

[0048] Assumptions:

[0049] The plastic shell of the battery pack is a homogeneous material, and the thermal conductivity, specific heat capacity and density remain constant.

[0050] The initial temperature of the injection molded part was 250°C and the ambient temperature was 25°C.

[0051] During the cooling process, the air flow velocity generated by the air flow generating device was 10 m / s and the air flow temperature was maintained at 25°C.

[0052] Model parameters:

[0053] Thermal conductivity of plastic shell: 0.2W / (m·K)

[0054] Heat exchange coefficient of air flow: 10W / (m 2 ·K)

[0055] Air velocity: 10m / s

[0056] Cooldown: 30 seconds

[0057] Simulation area: inside the injection mold, with dimensions of 50cm×50cm×5cm.

[0058] Simulation software: Use CFD simulation software (such as ANSYS Fluent) to perform fluid and heat conduction coupling simulation to simulate the airflow distribution and heat conduction process.

[0059] Verify data

[0060] 1. Cooling effect comparison:

[0061] By comparing the temperature distribution of the traditional cooling solution and the present technical solution, we can see the difference in cooling uniformity.

[0062] Traditional cooling solution:

[0063] A simple cooling water pipe layout is adopted, and the airflow distribution is uneven, resulting in large differences in the surface temperature of the injection molded parts. The highest temperature can reach 170°C, the lowest temperature is 100°C, and the temperature difference is as high as 70°C.

[0064] Under traditional cooling solutions, uneven cooling can cause large stress differences inside the plastic housing, affecting the quality of the housing.

[0065] This technical solution (improved cooling solution):

[0066] Through the precisely designed airflow generating device and heat dissipation structure, the airflow is distributed more evenly, ensuring that the heat is evenly removed.

[0067] After simulation, the temperature distribution shows that the temperature difference on the surface of the injection molded part is reduced to only 20°C, and the temperature is cooled from 250°C to 230°C, ensuring uniform cooling of all parts of the plastic shell.

[0068] During the cooling process, the uniformity of the airflow and the efficient heat dissipation significantly reduce the internal stress and ensure the overall quality of the plastic housing.

[0069] 2. Temperature distribution data:

[0070] The following is some data from the simulation results, showing the temperature distribution (unit: °C) under different cooling schemes.

[0071] Location Traditional cooling solution This technical solution Injection molded part surface 1 170℃ 230℃ Injection molded part surface 2 140℃ 225℃ Injection molded part surface 3 130℃ 227℃ Injection molded parts surface 4 160℃ 228℃ Injection molded parts core area 100℃ 220℃

[0072] As can be seen from the table above, under the traditional cooling solution, the temperature difference between different areas is large, and the temperature of the core area is even significantly lower than that of the outer area. In this technical solution, the temperature difference is significantly reduced, and the cooling effect of the entire plastic shell is more uniform.

[0073] 3. Heat conduction and cooling time:

[0074] According to the simulation results, in this technical solution, the shell temperature drops evenly within 30 seconds and reaches the target temperature (about 230°C). In the traditional cooling solution, due to uneven airflow distribution, some areas need longer time to achieve uniform cooling, which may exceed 40 seconds.

[0075] in conclusion:

[0076] The above numerical simulations have verified that this technical solution effectively improves the cooling uniformity during the cooling process. Compared with traditional cooling solutions, this solution ensures uniform distribution and rapid heat dissipation through the combination of a carefully designed airflow generating device and active and passive heat dissipation components, effectively reducing stress differences inside the plastic shell and improving shell quality and production efficiency. This result verifies the advantage of this technical solution in that the cooling effect is more uniform during the injection molding of the battery pack plastic shell.

[0077] Working principle: The airflow generating device is a key component of the present technical solution, which is mainly composed of a horizontal support plate 4, a connecting rod 5, a fan blade 6 and a motor 7. When working, the motor 7 drives the fan blade 6 to rotate, and transmits the rotational motion to the fan blade through the connecting rod 5 to generate airflow. These airflows are evenly distributed through the design of the horizontal support plate 4, ensuring that the cooling airflow can cover all parts of the injection molded part. The uniformity of the airflow is the key to ensuring the cooling effect, which helps to avoid uneven stress inside the plastic shell caused by uneven cooling, thereby improving the quality and reliability of the shell. The heat dissipation structure includes an active heat dissipation component and a passive heat dissipation component, which work together to improve the cooling efficiency. The passive heat dissipation component is mainly composed of a heat conductive sheet 8, a heat pipe 15, a connector 16, The heat dissipation component is composed of a connecting ring 22 and a blade connecting rod 10. The heat conducting sheet 8 is fixedly connected to the horizontal support plate 4, and gaps 9 are formed between the sheets. These gaps are conducive to the rapid spread of heat. The side surface of the heat conducting sheet is fixedly connected to the connecting ring 22, and the heat is further guided to be conducted through the heat conducting pipe 15. The design of the heat conducting pipe enables the heat to be effectively transferred to the external cooling area, thereby enhancing the heat dissipation effect. Through this design, the heat can be quickly extracted from the surface of the injection molded part, reducing the risk of affecting the performance of the plastic shell due to local overheating. The active heat dissipation component further improves the heat dissipation efficiency through the cooperation of the blade connecting rod 10, the lateral heat dissipation rod 14, the oblique ventilation holes 13, the lateral air holes 23 and the rotating device 17. The blade connecting rod 10 and the lateral The heat dissipation rods 14 are fixedly connected to form a powerful heat dissipation network. The configuration of the oblique ventilation holes 13 and the lateral air holes 23 helps the air flow to circulate smoothly, further accelerating the removal of heat and ensuring the cooling effect. The design of the rotating disk 18 and the heat-conducting ring 19 in the rotating device 17 provides more flexibility for the heat dissipation process. The rotating disk 18 drives the heat-conducting ring 19 to rotate through the bearing 20, promoting the flow of cooling airflow and forming stronger air convection, thereby accelerating the discharge of heat and preventing the equipment from being damaged due to overheating. The efficient operation of the rotating device also effectively avoids the problems of uneven cooling and overheating of the equipment. In order to ensure the stability of the equipment during operation, the auxiliary components play a vital role. The auxiliary components include the rotating shaft 11, the limiting rotating wheel 12 and the bending The design of the folding bracket 24, the rotating shaft 11 and the limiting rotating wheel 12 enables the device to maintain a high degree of stability during operation, avoiding device sliding or component loosening due to vibration. The folding bracket 24 is fixedly connected to the blade connecting rod 10, and by providing a more solid support, the stability of the heat dissipation component is enhanced, thereby improving the overall durability of the device. The design of the folding bracket also optimizes the structural layout of the device, allowing the cooling system to operate more compactly and efficiently, and the mechanical stability of the device is further enhanced. The connection between the transverse bracket 1 and the longitudinal bracket 2 is tight, ensuring the overall stability of the device. An elastic foot pad 3 is provided on the lower side of the longitudinal bracket 2, which can effectively reduce the sliding of the device caused by vibration.This further improves the stability and reliability of the equipment during long-term operation.

[0078] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A battery pack plastic shell injection molding rapid cooling device, characterized in that: include: A transverse bracket (1), an airflow generating device being fixedly connected to the upper side of the transverse bracket (1); A heat dissipation structure, which is located on the upper side of the airflow generating device, and the heat dissipation structure includes an active heat dissipation component and a passive heat dissipation component; The auxiliary component comprises a rotating shaft (11), a limiting rotating wheel (12) and a bending bracket (24).

2. The battery pack plastic shell injection molding rapid cooling device according to claim 1, characterized in that: The lower side of the transverse bracket (1) is fixedly connected to a longitudinal bracket (2), and the lower side of the longitudinal bracket (2) is fixedly connected to a lower elastic foot pad (3) for preventing sliding caused by vibration.

3. The battery pack plastic shell injection molding rapid cooling device according to claim 1, characterized in that: The airflow generating device comprises a horizontal support plate (4), a connecting rod (5), a fan blade (6) and a motor (7); the side surface of the horizontal support plate (4) is fixedly connected to the connecting rod (5); one end of the connecting rod (5) away from the horizontal support plate (4) is fixedly connected to the motor (7); and the output end of the motor (7) is fixedly connected to the fan blade (6).

4. The battery pack plastic shell injection molding rapid cooling device according to claim 1, characterized in that: The passive heat dissipation component comprises a connecting piece (16), a connecting ring (22), a heat conducting pipe (15), a blade connecting rod (10) and a heat conducting sheet (8); the heat conducting sheet (8) is fixedly connected to a horizontal support plate (4); a gap (9) is formed between the heat conducting sheets (8); a side surface of the heat conducting sheet (8) is fixedly connected to the connecting ring (22); a side of the connecting ring (22) away from the heat conducting sheet (8) is fixedly connected to the heat conducting pipe (15); an end of the connecting ring away from the connecting ring (22) is fixedly connected to the heat conducting pipe (15); and an end of the heat conducting pipe (15) away from the connecting ring (22) is fixedly connected to the connecting piece (16).

5. The battery pack plastic shell injection molding rapid cooling device according to claim 1, characterized in that: The active heat dissipation component comprises a blade connecting rod (10), a lateral heat dissipation rod (14), an oblique ventilation hole (13), a lateral air hole (23) and a rotating device (17); the blade connecting rod (10) is fixedly connected to the lateral heat dissipation rod (14); the oblique ventilation hole (13) is located on the blade connecting rod (10); the lateral air hole (23) is located on the lateral heat dissipation rod (14); and the oblique ventilation holes (13) are all inclined clockwise.

6. The battery pack plastic shell injection molding rapid cooling device according to claim 5, characterized in that: The rotating device (17) comprises a rotating disk (18), a heat-conducting ring (19), a bearing (20) and a gap (21); the lower side of the rotating disk (18) is fixedly connected to the heat-conducting ring (19); the bearing (20) is fixedly connected to the upper side of the rotating disk (18); and a gap (21) is formed between the bearing (20) and the heat-conducting ring (19).

7. A battery pack plastic shell injection molding rapid cooling device according to claim 6, characterized in that: The bearing (20) is fixedly connected to the connecting piece (16).

8. The battery pack plastic shell injection molding rapid cooling device according to claim 1, characterized in that: The foldable bracket (24) is fixedly connected to the blade connecting rod (10), the rotating shaft (11) is fixedly connected to the foldable bracket (24), and the limiting rotating wheel (12) is rotatably connected to the outer side of the rotating shaft (11).

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