High-efficiency heat dissipation type permanent magnet synchronous motor

Abstract

The application discloses a high-efficiency heat dissipation type permanent magnet synchronous motor and relates to the technical field of motors.The high-efficiency heat dissipation type permanent magnet synchronous motor comprises a shell, a stator fixedly arranged on the shell, a central rotating shaft arranged in the shell, a rotor arranged on the central rotating shaft and matched with the stator, a phase change cavity arranged in the central rotating shaft and filled with cooling liquid, an evaporation cavity close to the rotor and a condensation cavity away from the rotor arranged along the axial direction of the phase change cavity, and the evaporation cavity and the condensation cavity are connected through a steam passage and have a short heat dissipation path.The phase change cavity is directly arranged in the central rotating shaft, the evaporation end is close to the main heat source area of the rotor and the stator, the cooling liquid absorbs heat and changes phase at the evaporation end, the latent heat of vaporization is used to efficiently take away heat, compared with the traditional shell liquid cooling mode which can only indirectly cool the rotor, the heat dissipation path of the application is shorter, the thermal resistance is smaller, the rotor permanent magnet temperature rise can be directly inhibited, and the risk of high-temperature demagnetization can be effectively avoided.

Description

Technical Field

[0001] This application relates to the field of motor technology, and in particular to a high-efficiency heat-dissipating permanent magnet synchronous motor. Background Technology

[0002] Permanent magnet synchronous motors are widely used in new energy vehicles, aerospace, and high-end industrial drive fields due to their high efficiency, high power density, and good control performance. As motors develop towards miniaturization and high power density, the losses per unit volume increase, leading to a sharp rise in winding and rotor temperatures. High temperatures not only reduce the performance of permanent magnet materials and may even cause irreversible demagnetization, but also accelerate the aging of insulation materials, seriously affecting the reliability and lifespan of the motor.

[0003] Traditional motor cooling methods are mainly divided into air cooling and liquid cooling. Air cooling has a simple structure but limited heat dissipation efficiency, making it difficult to meet the heat dissipation requirements of high power density motors. Liquid cooling has strong heat dissipation capacity, but it usually requires complex cooling water channels to be arranged on the casing or rotor. Heat must pass through the rotor air gap, stator yoke, and casing in sequence before it can be carried away. This indirect cooling method is merely a passive "environmental cooling" for the rotor, with low heat dissipation efficiency and difficulty in suppressing the temperature rise of permanent magnets. Summary of the Invention

[0004] To address the issue of long indirect cooling paths, this application provides a high-efficiency heat dissipation permanent magnet synchronous motor.

[0005] The high-efficiency heat-dissipating permanent magnet synchronous motor provided in this application adopts the following technical solution: A high-efficiency heat dissipation permanent magnet synchronous motor includes a housing and a stator fixedly mounted thereon. A central rotating shaft is disposed through the housing, and a rotor that cooperates with the stator is disposed on the central rotating shaft. A phase change cavity that is evacuated and filled with coolant is opened inside the central rotating shaft. The phase change cavity includes an evacuation cavity close to the rotor and a condensation cavity away from the rotor along the axial direction. The evaporation cavity and the condensation cavity are connected by a vapor channel and the heat dissipation path is short. The phase change cavity is equipped with an adjustment component on the steam passage that spans the evaporation cavity and the condensation cavity in the middle. The steam passage opening is automatically adjusted according to temperature changes. A cooling box is fixedly installed inside the housing and surrounds the condensation cavity.

[0006] By adopting the above technical solution, the phase change cavity inside the central rotating shaft is evacuated and filled with coolant to form a sealed phase change space. When the motor is running, the heat generated by the rotor and stator causes the coolant in the evaporation cavity to absorb heat and evaporate into steam. The steam flows to the condensation cavity through the steam channel. An adjustment component is installed across the steam channel to automatically adjust the opening of the steam channel according to temperature changes, thereby controlling the steam flow rate. At the same time, a cooling box is fixedly installed inside the casing to surround the condensation cavity. The external cooling medium assists the condensation cavity in dissipating heat, allowing the steam to condense and release heat in the condensation cavity, completing the phase change cycle.

[0007] Preferably, the adjustment component includes a constraint ring fixedly disposed with the phase change cavity, a first slide rail fixedly disposed on the constraint ring, a second slide rail fixedly disposed in the evaporation cavity, a movable column slidably disposed through the constraint ring and the first slide rail, an opening groove extending to the movable column symmetrically opened on the first slide rail, a microfilament bundle fixedly disposed in the second slide rail, and the movable column is prevented from excessive displacement by a limiting structure.

[0008] By adopting the above technical solution, when the temperature rises, the microfilament bundle shrinks due to heat. One end of the microfilament bundle is fixed to the second slide, and the other end pulls the moving column to slide along the first slide and the constraint ring. The movement of the moving column changes the opening of the slot. At the same time, the moving column is prevented from excessive displacement by the limiting structure, ensuring the accuracy and reliability of the adjustment.

[0009] Preferably, the limiting structure includes a limiting groove formed in the first slide rail, a limiting ring slidably disposed in the limiting groove and fixedly connected to the moving column, and a return spring fixedly disposed between the limiting ring and the limiting groove.

[0010] By adopting the above technical solution, when the microfilament bundle contracts and pulls the moving column, the limiting ring slides synchronously in the limiting groove, limiting the stroke range of the moving column and preventing its excessive displacement; when the temperature decreases and the microfilament bundle relaxes, the elastic force of the reset spring pushes the limiting ring to drive the moving column to reset, close the steam channel, and realize the automatic adjustment function.

[0011] Preferably, the condensation chamber is provided with a conical inclined surface for driving the coolant backflow under the action of centrifugal force generated by the high-speed rotation of the rotor.

[0012] By adopting the above technical solution, when the motor rotates at high speed, the coolant in the condensation chamber is thrown towards the conical inclined surface under the action of centrifugal force. Due to the inclination angle of the inclined surface, the centrifugal force is decomposed into an axial component force along the direction of the inclined surface towards the evaporation chamber, thereby driving the condensant to automatically flow back to the evaporation chamber, ensuring that the cooling working fluid continues to circulate in the phase change chamber and avoiding the drying up of the evaporation end.

[0013] Preferably, the conical inclined surface has a guide groove at one end near the constraint ring to accelerate the return of coolant from the condensation chamber to the evaporation chamber, and the guide groove extends into the evaporation chamber.

[0014] By adopting the above technical solution, when the condensate flows back along the conical inclined surface under the action of centrifugal force, the guide channel guides the liquid to flow quickly to the evaporation chamber along a specific path, shortening the reflux time, while increasing the contact area between the liquid and the wall, accelerating heat transfer, and further improving heat dissipation efficiency.

[0015] Preferably, the cooling box is equipped with a centrifugal impeller fixedly connected to the central rotating shaft, and the cooling box is fixedly connected to an input pipe and an output pipe.

[0016] By adopting the above technical solution, when the central shaft rotates, the centrifugal impeller rotates synchronously, stirring the coolant in the cooling box and enhancing the convective heat transfer of the outer wall of the condensation chamber; the coolant enters the cooling box from the input pipe, absorbs heat and flows out from the output pipe, is cooled by the external cooling device and then circulated back in, so as to achieve continuous forced cooling of the condensation chamber.

[0017] Preferably, both the first and second slides are made of high-temperature resistant, self-lubricating ceramic materials to provide a stable installation and guiding foundation for shape memory alloy microfilament bundles and moving columns in a high-speed rotation environment.

[0018] By adopting the above technical solution, the ceramic material can maintain structural stability under high-speed rotation and high-temperature environment of the motor, providing a reliable installation foundation and low-friction guidance for the shape memory alloy microfilament bundle and moving column, ensuring long-term precise operation of the adjustment component, and avoiding jamming failure caused by thermal deformation or wear.

[0019] Preferably, the end of the microfilament bundle away from the second slide is fixedly connected to the moving column.

[0020] By adopting the above technical solution, when the microfilament bundle shrinks due to heat, it directly pulls the moving column through the fixed connection point to achieve precise conversion between temperature and displacement, ensuring the response speed and reliability of the adjustment action.

[0021] Preferably, the size of the limiting ring is adapted to that of the limiting groove.

[0022] By adopting the above technical solution, this adaptive design ensures that the limiting ring slides smoothly in the limiting groove, which not only effectively limits the stroke of the moving column, but also avoids shaking or jamming due to excessive gap, thus ensuring the stability of the adjustment component's movement and the effective transmission of the reset spring force.

[0023] Preferably, the microfilament bundle is formed by winding ternary shape memory alloy wire.

[0024] By adopting the above technical solution, this alloy has excellent shape memory effect and temperature sensitivity, and can produce significant shrinkage deformation within a specific temperature range. It also has a fast response speed and a large recovery force, thereby accurately driving the regulating component to automatically adjust the steam channel opening according to the real-time temperature change of the motor, thus realizing intelligent heat dissipation control.

[0025] In summary, this application includes at least one of the following beneficial technical effects: 1. In this application, the phase change cavity is directly opened inside the central rotating shaft, with the evaporation end close to the main heat source area of ​​the rotor and stator. The coolant absorbs heat at the evaporation end and undergoes a phase change, using the latent heat of vaporization to efficiently remove heat. A cooling box and a centrifugal impeller are set outside the condensation cavity. The rotation of the rotating shaft drives the impeller to stir the coolant, enhancing the convective heat transfer on the outer wall of the condensation cavity. The coolant forms a circulation loop with the external radiator through the output pipe, ultimately dissipating the heat outside the motor. Compared with the traditional casing liquid cooling method that can only indirectly cool the rotor, the heat dissipation path of this invention is shorter and the thermal resistance is lower. It can directly suppress the temperature rise of the rotor permanent magnet, effectively avoid the risk of high-temperature demagnetization, and provide a guarantee for the high power density operation of the motor.

[0026] 2. This application uses NiTiCu shape memory alloy microfilament bundles as temperature sensing and driving elements. Utilizing the shape memory effect and the shrinkage characteristics generated by temperature changes, the opening of the slot is automatically adjusted. When the motor temperature rises, the microfilaments contract and pull the moving column to move, increasing the opening of the steam channel in the slot and allowing more high-temperature steam to flow into the condensation chamber. When the temperature drops, the microfilaments relax, and the return spring pushes the moving column to close the slot. This design achieves intelligent adjustment of heat dissipation capacity and heat generation in real time, avoiding heat loss caused by excessive cooling at low temperatures and preventing insufficient heat dissipation at high temperatures, embodying the control concept of "heat dissipation on demand".

[0027] 3. This invention cleverly utilizes the centrifugal force generated by the rotation of the motor itself. The inner wall of the condensing chamber is designed as a conical inclined surface at a specific angle. Under the action of centrifugal force, the condensate is thrown out of the condensing chamber. The inclination angle of the inclined surface decomposes the centrifugal force into an axial component along the inclined surface towards the evaporation end, driving the condensate to flow back quickly. The spiral micro-textured guide grooves engraved on the inclined surface further guide the liquid to flow along the spiral path, which shortens the return path and enhances the heat exchange area. This design requires no external pumping power, achieving a completely self-driven working fluid circulation, and is particularly suitable for high-speed rotation conditions. Attached Figure Description

[0028] Figure 1 This is a three-dimensional schematic diagram of the overall structure of this application; Figure 2 This is a top view of the overall structure of this application; Figure 3 This is a schematic diagram of the internal structure of the casing in this application; Figure 4 This is a schematic diagram of the stator and rotor structure of this application; Figure 5 This is a cross-sectional view of the central axis of this application; Figure 6 for Figure 5 Enlarged structural diagram at point A in the middle; Figure 7 This is a schematic diagram of the adjustment component structure of this application; Figure 8 for Figure 7 Enlarged structural diagram at point B.

[0029] Reference numerals: 1. Housing; 2. Stator; 3. Rotor; 4. Central shaft; 5. Phase change chamber; 51. Evaporation chamber; 52. Condensation chamber; 53. Conical inclined surface; 54. Guide channel; 6. Cooling box; 61. Centrifugal impeller; 62. Inlet pipe; 63. Outlet pipe; 7. Adjustment component; 71. Constraint ring; 72. First slide rail; 73. Second slide rail; 74. Microfilament bundle; 75. Moving column; 76. Limiting groove; 77. Limiting ring; 78. Return spring; 79. Opening groove. Detailed Implementation

[0030] The following is in conjunction with the appendix Figures 1-8 This application will be described in further detail.

[0031] This application discloses a high-efficiency heat-dissipating permanent magnet synchronous motor.

[0032] Reference Figures 1 to 7 A high-efficiency heat-dissipating permanent magnet synchronous motor includes a housing 1 and a stator 2 fixedly installed in the housing 1. A central rotating shaft 4 is rotatably connected through the interior of the housing 1. The end of the central rotating shaft 4 located outside the housing 1 is the drive end of the motor. A rotor 3 is installed on the outer wall of the central rotating shaft 4 inside the housing 1. The rotor 3 cooperates with the stator 2 to rotate the central rotating shaft 4. A phase change cavity 5 is opened inside the central rotating shaft 4 inside the housing 1. The phase change cavity 5 is evacuated and filled with coolant. The phase change cavity 5 includes an evaporation cavity 51 close to the rotor 3 and a condensation cavity 52 away from the rotor 3 along the axial direction. The coolant is located inside the evaporation cavity 51. The evaporation cavity 51 and the condensation cavity 52 are connected by a steam channel, and the heat dissipation path is short and the thermal resistance is smaller. This can directly suppress the temperature rise of the permanent magnet of the rotor 3, effectively avoid the risk of high-temperature demagnetization, and provide a guarantee for the high power density operation of the motor. An adjustment component 7 is installed in the middle of the phase change chamber 5, spanning the steam passage between the evaporation chamber 51 and the condensation chamber 52. The adjustment component 7 is used to automatically adjust the opening of the steam passage according to temperature changes. A cooling box 6 is fixedly installed inside the casing 1. The cooling box 6 surrounds the central rotating shaft 4 around the condensation chamber 52. The central rotating shaft 4 is slidably disposed with the inner side of the cooling box 6. The cooling box 6 is filled with circulating external coolant. Due to the high-speed rotation of the central rotating shaft 4, a dynamic sealing ring is used at the junction of the cooling box 6 and the central rotating shaft 4 to prevent leakage.

[0033] When the motor starts running, the rotor 3 and stator 2 work together to generate electromagnetic torque. Simultaneously, the heat generated by both is conducted to the central shaft 4. The phase change chamber 5 inside the central shaft 4 is evacuated and filled with coolant. The coolant in the evaporation chamber 51, near the heat source, absorbs heat and rapidly boils and evaporates, becoming high-temperature steam. Because the steam channel between the evaporation chamber 51 and the condensation chamber 52 has a short heat dissipation path, the steam quickly flows through the steam channel to the condensation chamber 52, which is farther from the heat source. During the steam flow, the regulating component 7, located in the middle of the steam channel, automatically adjusts the opening of the steam channel according to real-time temperature changes, controlling the steam flow rate. After the high-temperature steam reaches the condensation chamber 52, it is continuously cooled by the cooling box 6 surrounding the condensation chamber 52. The steam condenses into liquid on the inner wall of the condensation chamber 52, releasing its latent heat of vaporization. The condensate then returns to the evaporation chamber 51 through a reflux mechanism, completing a full phase change heat dissipation cycle and achieving efficient heat dissipation for the motor.

[0034] Reference Figures 6 to 8 The adjustment assembly 7 includes a constraint ring 71 fixedly disposed with the phase change cavity 5. The constraint ring 71 is located in the middle of the phase change cavity 5. A first slide rail 72 is fixedly connected to the middle of the constraint ring 71. A second slide rail 73 is fixedly installed on the inner wall of the evaporation cavity 51. A movable column 75 is slidably installed through the constraint ring 71 and the first slide rail 72. The outer wall of the movable column 75 is in contact with the inner wall of the constraint ring 71 of the first slide rail 72 to prevent steam from passing through the gap between the movable column 75 and the first slide rail 72. Opening slots 79 are symmetrically opened on the first slide rail 72. Both opening slots 79 extend to the outer wall of the movable column 75. A microfilament bundle 74 is fixedly installed in the second slide rail 73. One end of the microfilament bundle 74 is located in the second slide rail 73. The movable column 75 is prevented from excessive displacement by a limiting structure. The first slide rail 72 and the second slide rail 73 are both made of high temperature resistant, self-lubricating ceramic material to provide a stable installation and guiding foundation for the shape memory alloy microfilament bundle 74 and the movable column 75 in a high-speed rotation environment. The end of the microfilament bundle 74 away from the second slide rail 73 is fixedly connected to the moving column 75. The microfilament bundle 74 is made of ternary shape memory alloy wire, and its main components are nickel (Ni), titanium (Ti) and copper (Cu).

[0035] Initially, the end face of the moving column 75 is flush with the end face of the constraint ring 71, at which point the moving column 75 blocks the opening slot 79. When the motor temperature rises, the microfilament bundle 74, made of ternary shape memory alloy wire fixed in the second slide rail 73, contracts instantaneously upon heating. Since the end of the microfilament bundle 74 away from the second slide rail 73 is fixedly connected to the moving column 75, the contracted microfilament bundle 74 pulls the moving column 75 away from the condensing chamber 52 through the fixed connection point. The moving column 75 slides within the through constraint ring 71 and the first slide rail 72. As the moving column 75 moves, the opening of the opening slot 79 gradually increases, allowing more high-temperature steam to flow into the condensing chamber 52. During this process, both the first slide rail 72 and the second slide rail 73 are made of high-temperature resistant, self-lubricating ceramic material, providing a stable installation and guiding foundation for the microfilament bundle 74 and the moving column 75 in a high-speed rotation environment, ensuring smooth sliding and protection from high temperatures. At the same time, the moving column 75 is prevented from excessive displacement by a limiting structure, ensuring adjustment accuracy.

[0036] Reference Figures 6 to 8 The limiting structure includes a limiting groove 76 formed in the first slide rail 72. The limiting groove 76 is cylindrical. A limiting ring 77 is slidably connected in the limiting groove 76. The inner side of the limiting ring 77 is fixedly connected to the outer wall of the moving column 75. A return spring 78 is fixedly installed between the limiting ring 77 and the side of the limiting groove 76 away from the limiting ring 77. The movement of the limiting ring 77 compresses the return spring 78. The size of the limiting ring 77 and the limiting groove 76 are matched to ensure that the limiting ring 77 slides smoothly in the limiting groove 76.

[0037] During the contraction of the microfilament bundle 74, which pulls the moving column 75, the limiting ring 77, which is fixedly connected to the moving column 75, slides synchronously within the limiting groove 76 opened in the first slide rail 72. The dimensions of the limiting ring 77 and the limiting groove 76 are matched to form a precise sliding fit, ensuring that the limiting ring 77 moves smoothly within the limiting groove 76, thereby limiting the stroke range of the moving column 75 and preventing it from being damaged or failing due to excessive displacement. When the motor temperature decreases and the microfilament bundle 74 relaxes, the return spring 78, which is fixed between the limiting ring 77 and the limiting groove 76, releases its elastic force, pushing the limiting ring 77 to drive the moving column 75 to move in the opposite direction and reset, closing the opening groove 79. This process realizes the intelligent adjustment function of automatically opening and closing the steam passage according to temperature changes.

[0038] Reference Figures 5 to 8A conical inclined surface 53 is provided on the condensing chamber 52. The conical inclined surface 53 is used to drive the coolant back under the action of centrifugal force generated by the high-speed rotation of the rotor 3. A guide groove 54 is provided at one end of the conical inclined surface 53 near the constraint ring 71. The guide groove 54 is used to accelerate the return of coolant from the condensing chamber 52 to the evaporating chamber 51. The guide groove 54 extends into the evaporating chamber 51 to transport the condensed coolant into the evaporating chamber 51. After the steam is generated in the evaporating chamber 51, it flows along the axis to the condensing chamber 52 with lower pressure. The condensed droplets adhere to the wall under the action of centrifugal force. The wall of the condensing chamber 52 is designed with a 4-degree half-cone angle. The spiral rise angle of the spiral guide groove 54 needs to be set to 25 degrees to counteract the Coriolis force interference caused by the rotational angular velocity gradient and ensure that the condensant can flow back smoothly to the evaporating chamber 51.

[0039] When the high-temperature steam reaches the condensing chamber 52 and is cooled by the cooling box 6, the steam condenses into liquid on the inner wall of the condensing chamber 52. Under the strong centrifugal force generated by the high-speed rotation of the motor rotor 3, the condensate is firmly thrown towards the conical inclined surface 53 provided on the condensing chamber 52. Since the tip of the conical inclined surface 53 is close to the constraint ring 71, the centrifugal force is converted into an axial force that flows back along the inclined surface towards the evaporating chamber 51, driving the condensate to flow into the evaporating chamber 51. When the condensate flows along the conical inclined surface 53, it enters the guide groove 54 opened at one end of the inclined surface near the constraint ring 71. The guide groove 54 extends into the evaporating chamber 51. The spiral shape of the guide groove 54 guides the condensate to flow rapidly along a specific path, accelerating the condensate's return flow from the condensing chamber 52 to the evaporating chamber 51, ensuring continuous circulation of the coolant and preventing the evaporating chamber 51 from drying out.

[0040] Reference Figures 1 to 5 A centrifugal impeller 61 is installed inside the cooling box 6. The inner side of the centrifugal impeller 61 is fixedly connected to the outer wall of the central rotating shaft 4. An input pipe 62 and an output pipe 63 are fixedly connected inside the cooling box 6. The input pipe 62 is located at the top of the cooling box 6, and the output pipe 63 is located at the bottom of the cooling box 6. The inlet of the input pipe 62 faces the fan blade of the centrifugal impeller 61.

[0041] While the central shaft 4 drives the rotor 3 to rotate at high speed, the centrifugal impeller 61, which is fixedly connected to the central shaft 4, rotates synchronously at high speed inside the cooling tank 6. The rotation of the centrifugal impeller 61 strongly agitates the coolant inside the cooling tank 6, causing forced convection of the coolant on the outer wall of the condensing chamber 52, efficiently removing heat from the wall of the condensing chamber 52. The coolant continuously enters the cooling tank 6 from the inlet pipe 62, absorbs heat, and its temperature rises before flowing out of the cooling tank 6 from the outlet pipe 63. The high-temperature coolant is transported to a cooling device outside the motor for cooling, and the cooled coolant is then reintroduced into the cooling tank 6 through the inlet pipe 62, forming a closed loop that continuously provides cooling capacity to the condensing chamber 52, ensuring the stable and efficient operation of the entire phase change heat dissipation system.

[0042] Among them, the adjustment component 7, the conical inclined surface 53 and the guide groove 54 are all coaxially arranged with the central rotating shaft 4, and the opening groove 79 is symmetrically opened with the central axis of the central rotating shaft 4 to achieve balance during high-speed rotation.

[0043] The permanent magnet synchronous motor (PMSM) utilizes modern power electronics technology in conjunction with motor control strategies. The motor body employs a three-phase star or delta connection. The stator winding 2 is connected to an external motor controller via cables. The controller typically uses a digital signal processor or microcontroller as its core, paired with intelligent power modules or insulated-gate bipolar transistors (IGBTs) as power drive units. It also incorporates current Hall sensors and position sensors (such as rotary transformers or encoders) to monitor the stator current 2 and rotor position 3 in real time, sending feedback signals to the controller to form a closed-loop control circuit. For startup, since PMSMs cannot self-start, a variable frequency drive (VFD) is required: before startup, the controller obtains the initial position of rotor 3 using the position sensor; during startup, the controller adjusts the starting position according to the position signal. According to the magnetic field orientation control algorithm, the current vector of stator 2 is decomposed into excitation component and torque component, and a three-phase sinusoidal voltage is generated through space vector pulse width modulation technology to drive the inverter to output a power supply with variable voltage and variable frequency. The motor accelerates smoothly from zero frequency, and the rotating magnetic field of stator 2 is always synchronized with the magnetic field of rotor 3 until the target speed is reached. During the entire startup and operation process, the central shaft 4 rotates together with rotor 3, driving the centrifugal impeller 61 in the cooling chamber of the condenser end to rotate synchronously, and the coolant circulation is established immediately. At the same time, the temperature in the phase change chamber 5 gradually rises. When the temperature reaches the phase change point of NiTiCu shape memory alloy microfilament bundle 74, the microfilament bundle 74 shrinks due to heat and automatically adjusts the opening of the steam channel. The heat dissipation system then enters adaptive operation without the need for additional control circuit intervention.

[0044] The implementation principle of a high-efficiency heat dissipation permanent magnet synchronous motor according to an embodiment of this application is as follows: When the motor starts running, the heat generated by the rotor 3 and stator 2 is conducted to the central rotating shaft 4. The coolant in the vacuum phase change chamber 5 inside the shaft absorbs heat and evaporates into high-temperature steam in the evaporation chamber 51 near the heat source. The steam flows quickly to the condensation chamber 52 through the short-path steam channel. During the flow, the opening of the regulating component 7 is automatically adjusted according to the temperature to control the flow rate. The high-temperature steam is cooled and condensed into liquid by the outer cooling box 6 in the condensation chamber 52, releasing the latent heat of vaporization. The condensate then flows back to the evaporation chamber 51, completing the high-efficiency phase change heat dissipation cycle.

[0045] The above are merely optional embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A high-efficiency heat-dissipating permanent magnet synchronous motor, comprising a housing (1) and a stator (2) fixedly disposed therewith in the housing (1), wherein a central rotating shaft (4) is disposed through the housing (1), and a rotor (3) cooperating with the stator (2) is disposed on the central rotating shaft (4), characterized in that: The central rotating shaft (4) has a phase change cavity (5) that is evacuated and filled with coolant. The phase change cavity (5) includes an evaporation cavity (51) close to the rotor (3) and a condensation cavity (52) away from the rotor (3) along the axial direction. The evaporation cavity (51) and the condensation cavity (52) are connected by a steam channel and have a short heat dissipation path. The phase change cavity (5) is provided with an adjustment component (7) for automatically adjusting the opening of the steam passage according to temperature changes on the steam passage that spans the middle of the evaporation cavity (51) and the condensation cavity (52). A cooling box (6) is fixedly installed inside the housing (1) and surrounds the condensation cavity (52). The adjustment component (7) includes a constraint ring (71) fixedly disposed with the phase change cavity (5). A first slide rail (72) is fixedly disposed on the constraint ring (71). A second slide rail (73) is fixedly disposed in the evaporation cavity (51). A moving column (75) is slidably disposed through the constraint ring (71) and the first slide rail (72). An opening groove (79) extending to the moving column (75) is symmetrically opened on the first slide rail (72). A microfilament bundle (74) is fixedly disposed in the second slide rail (73). The moving column (75) is prevented from excessive displacement by a limiting structure. The microfilament bundle 74 is made of ternary shape memory alloy wire, and its main components are nickel (Ni), titanium (Ti) and copper (Cu). The limiting structure includes a limiting groove (76) opened in the first slide (72), a limiting ring (77) fixedly connected to the moving column (75) is slidably arranged in the limiting groove (76), and a return spring (78) is fixedly arranged between the limiting ring (77) and the limiting groove (76).

2. The high-efficiency heat-dissipating permanent magnet synchronous motor according to claim 1, characterized in that: The condensation chamber (52) is provided with a conical inclined surface (53) for driving the coolant back under the action of centrifugal force generated by the high-speed rotation of the rotor (3).

3. The high-efficiency heat-dissipating permanent magnet synchronous motor according to claim 2, characterized in that: The conical inclined surface (53) has a guide groove (54) at one end near the constraint ring (71) for accelerating the return of coolant from the condensation chamber (52) to the evaporation chamber (51), and the guide groove (54) extends into the evaporation chamber (51).

4. The high-efficiency heat-dissipating permanent magnet synchronous motor according to claim 1, characterized in that: The cooling box (6) is equipped with a centrifugal impeller (61) fixedly connected to the central rotating shaft (4), and the cooling box (6) is fixedly connected with an input pipe (62) and an output pipe (63).

5. The high-efficiency heat-dissipating permanent magnet synchronous motor according to claim 1, characterized in that: Both the first slide (72) and the second slide (73) are made of high-temperature resistant, self-lubricating ceramic materials, which are used to provide a stable installation and guiding foundation for the shape memory alloy microfilament bundle (74) and the moving column (75) in a high-speed rotation environment.

6. The high-efficiency heat-dissipating permanent magnet synchronous motor according to claim 1, characterized in that: The end of the microfilament bundle (74) away from the second slide (73) is fixedly connected to the movable column (75).

7. The high-efficiency heat-dissipating permanent magnet synchronous motor according to claim 1, characterized in that: The size of the limiting ring (77) is adapted to the size of the limiting groove (76).

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