Engineering machinery water-cooled permanent magnet motor with double-heat-pipe coupling cooling

Abstract

The invention relates to a high-power water-cooling permanent magnet synchronous motor for engineering machinery, in particular to a high-efficiency heat dissipation motor system adopting a double-heat-pipe coupling cooling structure, which is characterized in that array flat heat pipes and high-speed working condition self-backflow rotating heat pipes are respectively integrated in a stator and a rotor, so that stator-rotor double-channel, phase-change and rapid heat conduction is realized; and the thermal control capability and reliability of the motor are improved. According to the motor, a plurality of ultrathin flat heat pipes are symmetrically arranged on the outer circle of a stator and are in one-to-one correspondence with winding notches, so that a rapid and efficient stator heat conduction path is formed; and meanwhile, the hollow rotating shaft made of sintered copper powder is designed into a rotating heat pipe structure, so that the heat of the rotor can be quickly transferred to the water-cooling casing through a bearing area, and the efficient cooling of the rotor assembly is realized. The double-heat-pipe structure constructs a stator and rotor independent heat dissipation channel through a phase change heat transfer mechanism, motor size constraint is not changed, temperature rise of windings and permanent magnets is remarkably reduced, heat balance and system stability are improved, and the double-heat-pipe structure is particularly suitable for high-load working conditions such as engineering machinery.

Description

Technical Field

[0001] This invention relates to the field of motor thermal management technology, specifically to a high-power water-cooled permanent magnet synchronous motor for engineering machinery. In particular, it relates to a dual-channel, phase-change, rapid cooling structure for stators and rotors by integrating flat plate heat pipes and high-speed self-recirculating rotating heat pipes in the stator and rotor respectively, thereby significantly improving the thermal control capability and reliability of the high-power permanent magnet motor for engineering machinery. Background Technology

[0002] In recent years, the increasing global awareness of environmental protection and the trend of energy transition have prompted the transformation of traditional energy equipment to new energy equipment. Electrification, intelligentization, and green environmental protection have become important directions for the development of the construction machinery industry. As a crucial component of this transformation, the electric drive system, particularly the performance of high-power permanent magnet motors, is critical, directly determining the power, efficiency, and reliability of electric construction machinery. With the development of construction machinery towards electrification, high-power permanent magnet synchronous motors are increasingly widely used in mining trucks, electric excavators, electric loaders, and other fields. These applications often require motors with high torque output, high-load continuous operation capability, and good heat dissipation performance to cope with harsh environments and prolonged high-temperature conditions.

[0003] Currently, the thermal management structure of permanent magnet synchronous motors used in engineering machinery generally adopts a combination of water-cooled shell, natural heat conduction of the iron core, and axial air cooling / oil cooling as auxiliary heat dissipation. However, these methods still have the following obvious limitations in terms of temperature control of the two key heat sources: stator windings and rotor magnets: the heat conduction path from the stator windings and iron core to the shell is long, and the hot spots are unevenly distributed; the heat of the rotor permanent magnets is limited by the thermal resistance of the shaft and the bearing structure, making it difficult to dissipate quickly; traditional heat conduction has a slow thermal response speed and a certain thermal lag, which cannot adapt to temperature rise fluctuations under complex operating conditions. Summary of the Invention

[0004] The purpose of this invention is to provide a water-cooled permanent magnet motor for engineering machinery with dual heat pipe coupling cooling. Through the dual-channel thermal control structure of flat plate heat pipes on the stator core and self-recirculating rotating heat pipes under high-speed conditions, the motor achieves rapid, uniform, and directional heat transfer between the stator and rotor regions under space-constrained conditions, significantly improving the overall thermal management performance of the motor and making it suitable for harsh operating environments such as engineering machinery.

[0005] This invention provides a water-cooled permanent magnet motor for engineering machinery with dual heat pipe coupling cooling, comprising: Water-cooled casing, A stator assembly, comprising a stator core and windings arranged on the inner wall of the stator core; A flat plate heat pipe is disposed on the outer wall of the stator core and corresponds to the area where the winding is located; the evaporation section of the flat plate heat pipe is attached to the outer wall of the stator core, and the condensation section is in contact with the inner wall of the water-cooled housing; the heat generated by the winding operation can be transferred to the water-cooled housing through the stator core and the flat plate heat pipe. The rotor assembly includes a rotating shaft and a rotor core and a permanent magnet arranged on the rotating shaft. The rotating shaft includes a rotating heat pipe. The evaporation section of the rotating heat pipe is in contact with the rotor core, and the condensation sections at both ends are thermally coupled to the water-cooled housing through bearings at the ends of the rotating shaft. The heat generated by the rotor core and the permanent magnet during operation can be transferred to the water-cooled housing through the rotating heat pipe and the bearings.

[0006] Optionally, the flat heat pipe is arranged along the axial direction of the stator core, and the axial length of the flat heat pipe is 1 to 3 mm shorter than the axial length of the stator core.

[0007] Optionally, the flat plate heat pipe has a sintered porous capillary structure inside and is encapsulated with a phase change working fluid. The thickness of the flat plate heat pipe is 0.8mm~1.2mm and the width is 8mm~15mm.

[0008] Optionally, the outer wall of the stator core is provided with a heat-conducting groove or welding channel, and the flat heat pipe is fixed in the heat-conducting groove or welding channel by brazing material.

[0009] Optionally, the flat heat pipe is fixedly connected to the outer wall of the stator core by interference fit or high thermal conductivity adhesive.

[0010] Optionally, the rotating heat pipe includes a closed cavity structure filled with a phase change working fluid.

[0011] Optionally, the rotating heat pipe is a pre-formed shaft-embedded structure; the rotating heat pipe includes a shaft end, a left condensing section, an evaporating section, and a right condensing section; the evaporating section is in contact with the rotor core; the left and right condensing sections are located at the shaft ends at both ends and are in contact with bearings to form a heat channel with the water-cooled housing through the bearings.

[0012] Optionally, the rotating heat pipe is provided with a sintered porous structure liquid wick, which includes a condensation section liquid wick and an evaporation section liquid wick. The capillary diameter of the evaporation section liquid wick is 5-10 μm, and the capillary diameter of the condensation section liquid wick is 15-30 μm.

[0013] Optionally, it also includes: The front cover and the rear cover are respectively connected to the two ends of the rotating shaft through bearings. The front cover, the rear cover and the water-cooled housing are installed to form an assembly space, and the stator assembly and the rotor assembly are installed in the assembly space.

[0014] Optionally, a cooling water channel is formed inside the water-cooled housing, through which cooling water can enter and exit from the cooling water outlet; the cooling water channel adopts a double spiral channel or a partitioned serpentine channel.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention uses a flat heat pipe on the outer wall of the stator core to enable the heat generated by the winding operation to be quickly conducted radially to the water-cooled housing, forming a short-path, high-efficiency heat channel, improving the overall thermal uniformity and response speed of the stator, significantly reducing the stator temperature rise, and improving the thermal stress of the winding; the rotating heat pipe enables the rapid removal of axial heat under high-speed shaft rotation; the dual heat pipe structure works synergistically, with fast thermal response, smooth heat conduction, and large heat dissipation redundancy, which can adapt to temperature rise fluctuations under complex operating conditions. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a water-cooled permanent magnet motor for engineering machinery with dual heat pipe coupling cooling, as proposed in this invention. Figure 2 This is a schematic diagram of the stator assembly structure of the water-cooled permanent magnet motor proposed in this invention; Figure 3 This is a schematic diagram of the arrayed ultrathin flat plate heat pipe structure for the stator assembly of the present invention; Figure 4 This is a schematic diagram of the water-cooled permanent magnet motor rotor assembly structure proposed in this invention; Figure 5 This invention presents a schematic diagram of the high-speed self-reflux rotating heat pipe structure and its working principle. Figure 6 The wire mesh liquid-absorbing core used inside the ultrathin flat plate heat pipe proposed in this invention; Figure 7 The rotating heat pipe gradient liquid suction core proposed in this invention, Figure 7 (a) is a schematic diagram of the condenser end. Figure 7 (b) is a schematic diagram of the evaporation end.

[0017] Explanation of reference numerals in the attached diagram: 1. Stator assembly; 2. Rotor assembly; 3. Rear end cover; 4. Cooling water inlet; 5. Front end cover; 6. Cooling water outlet; 7. Cooling water channel; 8. Water-cooled housing; 9. Junction box; 11. Stator core; 12. Flat heat pipe; 13. Winding; 14. Insulating paper; 15. Core welding channel; 21. Shaft; 22. Bearing; 23. Dynamic balance plate; 24. Rotor core; 25. Permanent magnet; 26. Snap ring; 211. Shaft end; 212. Left condensing section; 213. Condensation section wick; 214. Evaporation section; 215. Evaporation section wick; 216. Right condensing section. Detailed Implementation

[0018] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more. In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0019] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0020] To make the purpose, technical solution and advantages of this invention patent clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0021] like Figure 1 As shown, the present invention provides a water-cooled permanent magnet motor for engineering machinery with dual heat pipe coupling cooling. The water-cooled permanent magnet motor for engineering machinery with dual heat pipe coupling cooling includes: stator assembly 1, rotor assembly 2, rear end cover 3, cooling water inlet 4, front end cover 5, cooling water outlet 6, cooling water channel 7, water-cooled housing 8, and junction box 9.

[0022] like Figure 2As shown, the stator assembly 1 includes a stator core 11, an array of ultra-thin flat heat pipes 12, windings 13, insulating paper 14, and core welding channels 15. Several ultra-thin flat heat pipes 12 are evenly arranged on the outer circumference of the stator core 11. The flat heat pipes 12 are installed one-to-one with the slots of the stator slots used to accommodate the windings 13. Each flat heat pipe 12 can quickly conduct the heat generated in the winding 13 area radially to the water-cooled housing 8, forming a short-path, high-efficiency heat channel, significantly improving the overall thermal uniformity and response speed of the stator, and achieving efficient stator cooling.

[0023] In this embodiment, the stator's directional heat conduction capability of the permanent magnet motor is significantly improved. By pre-setting an array of ultra-thin flat plate heat pipes 12 on the outer circumference of the stator core 11, and aligning the evaporation section of the flat plate heat pipes 12 with the high-heat area of ​​the stator core 11, and thermally coupling the condensation section with the water-cooled housing 8, the heat from the winding 13 can be quickly, evenly, and directionally conducted to the water-cooled housing 8, significantly reducing the stator temperature rise, improving the thermal stress of the winding, and extending the insulation life.

[0024] The surface of the stator core 11 is pre-set with slots or heat-conducting grooves corresponding to the flat heat pipe 12, which are used to accurately position and install the flat heat pipe 12, ensuring that the flat heat pipe 12 and the stator core 11 achieve surface contact, reducing thermal resistance and improving thermal coupling efficiency.

[0025] The stator assembly 1 adopts a centralized flat wire winding structure with the windings 13 arranged compactly. The flat heat pipe 12 is arranged along the stator lamination direction and parallel to the axial direction of the stator core 11, so as not to interfere with the motor assembly space, while retaining sufficient cross-sectional area of ​​the windings 13, taking into account both heat dissipation efficiency and motor performance.

[0026] like Figure 3 As shown, the flat heat pipe 12 has a sintered porous capillary structure inside. A specific embodiment of the sintered porous capillary structure is as follows: Figure 6 As shown, it has good capillary reflux capability and encapsulates low-pressure phase change working fluid (such as water or alcohol). Its evaporation section is attached to the high heat flux density area of ​​the outer wall of the stator core 11, while the condensation section is in close contact with the inner wall of the water-cooled housing 8 for thermal coupling, which is used to quickly transfer the heat absorbed by the evaporation section to the water-cooling system, forming a continuous thermal channel from the winding 13 to the water-cooled housing 8.

[0027] In this embodiment, the flat heat pipe 12 has a thickness of 0.8mm~1.2mm, a width of 8mm~15mm, and a length slightly shorter than the effective iron core length of the stator. The heat pipe body is made of copper-based composite material, which has both good thermal conductivity and strong formability, and is suitable for engineering machinery applications with high heat load and high space utilization of high-speed motors.

[0028] The flat heat pipe 12 is fixed to the stator core 11 by interference fit, brazing or high thermal conductivity adhesive to form a stable and reliable thermal interface, which effectively prevents the heat pipe from loosening or contact failure due to long-term vibration conditions, and ensures heat dissipation efficiency and structural safety under long-term working conditions.

[0029] Furthermore, to enhance cooling efficiency and installation adaptability, the thickness of the flat heat pipe 12 is controlled between 0.8mm and 1.2mm, the width is between 5mm and 15mm, and the length is set according to the effective length of the stator core, slightly shorter than the axial length of the stator core 11 by 1 to 3mm to avoid end interference. The flat heat pipe 12 can be automatically inserted into the preset heat-conducting groove or welding channel 15 on the outer circumference of the stator core 11 by laser positioning, and reliably fixed by high thermal conductivity brazing material. During motor assembly, after the flat heat pipe 12 is inserted into the corresponding slot, the flat wire winding 13 is arranged in the stator slot through a concentrated winding process, and then double-layer insulating paper 14 is laid in sequence. The condensation section of the flat heat pipe 12 is tightly attached to the outer wall of the water-cooled housing 8 on the outside of the core lamination.

[0030] like Figure 4 As shown, the rotor assembly 2 includes a shaft 21, a bearing 22, a dynamic balancing plate 23, a rotor core 24, a permanent magnet 25, and a retaining ring 26. Figure 5 As shown, the rotating shaft 21 includes a rotating heat pipe with a capillary reflux structure. The rotating heat pipe is pre-formed as an embedded structure within the rotating shaft 21 and has reserved assembly space at the end interface. The rotating heat pipe enables efficient conduction and rapid dissipation of heat inside the rotor, significantly reducing the risk of irreversible demagnetization of the permanent magnet due to excessive temperature rise. The shaft body of the rotating shaft 21 has a cavity low-pressure closed structure, which is filled with a phase change working fluid and includes a rotating shaft end 211, a left condensing section 212, an evaporation section 214, and a right condensing section 216. The evaporation section 214 of the rotating heat pipe is in direct contact with the rotor core 24 and is used to absorb the heat generated by the rotor core and permanent magnet during operation. The left condensing section 212 and the right condensing section 216 are located in the contact area of ​​the bearing 22 at the rotating shaft end 211. Through the bearing 22, they can form a heat channel with the water-cooled housing 8 to achieve heat conduction to the outside.

[0031] The rotating shaft 21 is designed as a high-speed self-reflux rotating heat pipe. The rotating heat pipe contains a sintered porous wicking core to drive stable reflux of the condensate during high-speed rotation. Specifically, the sintered porous wicking core includes a condensation section wicking core 213 and an evaporation section wicking core 215. The axial channel incorporates a gradient-distributed wicking core structure via a hot-pressing sintering process. The condensation section wicking core 213 uses porous copper powder with large pores, offering high permeability, facilitating rapid heat release, and reducing reflux resistance. This allows the condensate to flow quickly to both ends under centrifugal force, achieving gas-liquid separation, optimizing the internal heat circulation path, and effectively ensuring circulation stability under harsh conditions. The evaporation section wicking core 215 uses a porous copper powder structure with smaller pores to enhance capillary force, resisting centrifugal resistance under high-speed rotation, and ensuring reliable transport of the condensate against centrifugal force, guaranteeing directional reflux to the evaporation section. In one specific embodiment, the capillary pore size of the liquid suction core 215 in the evaporation section is 5-10 μm, and the capillary pore size of the liquid suction core 213 in the condensation section is 15-30 μm, so as to realize the gradient flow of capillary driving force, thereby overcoming the problem of strong centrifugal liquid ejection under high-speed rotation conditions, effectively solving the problem that the working fluid is prone to deviating from the evaporation zone under centrifugal force, and ensuring the stable operation of the heat pipe circulation under rotation conditions.

[0032] The cooling structure of the rotor assembly 2 in this embodiment breaks through the limitations of traditional arrangements. An axially dual-cold-end rotating heat pipe is integrated into the high-speed rotating shaft 21. The evaporation section of the rotating heat pipe is tightly fitted to the rotor core 24. The left condensation section 212 and the right condensation section 216 at both ends form efficient heat channels with the water-cooled housing 8 through the bearings 22 at both ends, achieving reliable heat output from the permanent magnet 25 under high-speed rotation. This effectively solves the problems of low cooling efficiency and long heat flow paths in traditional air-cooling and oil-cooling methods under high heat flux density environments. This structure also significantly enhances the external heat conduction efficiency of the shaft 21 while maintaining rotor strength and rigidity. Specific embodiments of the sintered porous capillary structure of the evaporation section 214 and condensation section of the rotating heat pipe are as follows... Figure 7 As shown in (a) and (b).

[0033] The rotating heat pipe is divided into a left condensation section 212, an evaporation section 214, and a right condensation section 216. The capillary gradient structure can effectively control the directional flow of condensate, achieving a stable cooling cycle under heavy load conditions. Heat is introduced from the rotor core 24 into the shaft 21. The vaporized steam migrates to the condensation zones at both ends under the action of pressure difference and centrifugal force. After condensation and heat release, it is conducted through the bearing 22 and the water-cooled housing 8. The condensate is then driven by the capillary structure to flow back to the evaporation section 214, forming a closed-loop thermal management path. To further improve the heat dissipation effect, a complete cooling water channel (7) is formed inside the water-cooled housing (8) during motor operation. Cooling water enters from the cooling water inlet (4), flows evenly through the stator and bearing seat through the internal guide structure, and is discharged from the cooling water outlet (6). The cooling water channel (7) can adopt a double spiral channel or a partitioned serpentine channel design to improve heat exchange efficiency and reduce the risk of local overheating.

[0034] The dual heat pipe structure of this embodiment possesses excellent thermal coupling capability and passive phase change heat transfer characteristics. The stator side employs an array of ultra-thin flat plate heat pipes 12 to achieve radial directional heat conduction, while the rotor side utilizes a built-in rotating heat pipe structure to achieve axial heat dissipation under high-speed rotation. These two structures are independent and do not interfere with each other, but they can work synergistically to achieve rapid and stable external heat conduction from the motor windings 13 and permanent magnets 25, greatly improving the overall thermal management capability of the machine. The bidirectional heat dissipation channel of this embodiment significantly shortens the heat flow path: heat is directly conducted to the water-cooled casing via independent heat pipe channels in the stator assembly 1 and rotor assembly 2, forming a dual heat dissipation path of "axial + radial" and "stator + rotor." Compared with traditional methods relying solely on stator water channels or forced air cooling, the thermal resistance is significantly reduced, and the system's thermal response speed is faster.

[0035] The dual heat pipe coupled cooling structure provided by this invention is particularly suitable for engineering machinery applications such as continuous heavy load, strong disturbance, and high ambient temperature. It is compatible with the S9 motor operating mode, which can effectively extend the motor life, avoid the risk of thermal runaway, and improve the reliability of the whole vehicle system.

[0036] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A water-cooled permanent magnet motor for engineering machinery with dual heat pipe coupled cooling, characterized in that, include: Water-cooled housing (8). The stator assembly (1) includes a stator core (11) and windings (13) arranged on the inner wall of the stator core (11). A flat plate heat pipe (12) is disposed on the outer wall of the stator core (11) and corresponds to the area where the winding (13) is located; the evaporation section of the flat plate heat pipe (12) is attached to the outer wall of the stator core (11), and the condensation section is in contact with the inner wall of the water-cooled housing (8); the heat generated by the operation of the winding (13) can be transferred to the water-cooled housing (8) through the stator core (11) and the flat plate heat pipe (12). The rotor assembly (2) includes a rotating shaft (21) and a rotor core (24) and a permanent magnet (25) arranged on the rotating shaft (21). The rotating shaft (21) includes a rotating heat pipe. The evaporation section (214) of the rotating heat pipe is in contact with the rotor core (24), and the condensation sections at both ends are thermally coupled to the water-cooled housing (8) through the bearings (22) at the ends of the rotating shaft. The heat generated by the rotor core (24) and the permanent magnet (25) during operation can be transferred to the water-cooled housing (8) through the rotating heat pipe and the bearings (22).

2. The water-cooled permanent magnet motor for engineering machinery with dual heat pipe coupled cooling as described in claim 1, characterized in that, The flat heat pipe (12) is arranged along the axial direction of the stator core (11), and the axial length of the flat heat pipe (12) is 1-3 mm shorter than the axial length of the stator core (11).

3. The water-cooled permanent magnet motor for engineering machinery with dual heat pipe coupled cooling as described in claim 1, characterized in that, The flat heat pipe (12) has a sintered porous capillary structure inside and is encapsulated with a phase change working fluid. The thickness of the flat heat pipe (12) is 0.8mm~1.2mm and the width is 8mm~15mm.

4. The water-cooled permanent magnet motor for engineering machinery with dual heat pipe coupled cooling as described in claim 1, characterized in that, The outer wall of the stator core (11) is provided with a heat-conducting groove or welding channel (15), and the flat heat pipe (12) is fixed in the heat-conducting groove or welding channel (15) by brazing material.

5. The water-cooled permanent magnet motor for engineering machinery with dual heat pipe coupling cooling as described in claim 1, characterized in that, The flat heat pipe (12) is fixedly connected to the outer wall of the stator core (11) by interference fit or high thermal conductivity adhesive.

6. The water-cooled permanent magnet motor for engineering machinery with dual heat pipe coupled cooling as described in claim 1, characterized in that, The rotating heat pipe includes a closed cavity structure filled with a phase change working fluid.

7. The water-cooled permanent magnet motor for engineering machinery with dual heat pipe coupling cooling as described in claim 1, characterized in that, The rotating heat pipe is a pre-formed structure embedded in a rotating shaft (21); the rotating heat pipe includes a rotating shaft end (211), a left condensing section (212), an evaporating section (214) and a right condensing section (216); the evaporating section (214) is in contact with the rotor core (24); the left condensing section (212) and the right condensing section (216) are located at the rotating shaft ends (211) at both ends and are in contact with the bearing (22) to form a heat channel with the water-cooled housing (8) through the bearing (22).

8. The water-cooled permanent magnet motor for engineering machinery with dual heat pipe coupled cooling as described in claim 1, characterized in that, The rotating heat pipe is provided with a sintered porous liquid wick, which includes a condensation section liquid wick (213) and an evaporation section liquid wick (215). The capillary diameter of the evaporation section liquid wick (215) is 5-10 μm, and the capillary diameter of the condensation section liquid wick (213) is 15-30 μm.

9. The water-cooled permanent magnet motor for engineering machinery with dual heat pipe coupled cooling as described in claim 1, characterized in that, Also includes: The front cover (5) and the rear cover (3) are respectively connected to the two ends of the rotating shaft (21) through bearings (22). The front cover (5), the rear cover (3) and the water-cooled housing (8) are installed to form an assembly space. The stator assembly (1) and the rotor assembly (2) are installed in the assembly space.

10. The water-cooled permanent magnet motor for engineering machinery with dual heat pipe coupled cooling according to claim 1, characterized in that, The water-cooled housing (8) forms a cooling water channel (7) inside, and the cooling water can enter through the cooling water inlet (4), pass through the cooling water channel (7), and then flow out through the cooling water outlet (6); the cooling water channel (7) adopts a double spiral channel or a partitioned serpentine channel.

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