Permanent magnet motor cooling device

Abstract

This invention discloses a cooling device for a permanent magnet motor, relating to the field of permanent magnet motor technology. It includes a heating component, a heat-conducting component disposed on the outer wall of the heating component, and a heat dissipation component disposed outside the heat-conducting component. The heating component includes a stator core and windings disposed on the inner wall of the stator core. The stator core and windings transfer heat to the heat dissipation component through the heat-conducting component. By embedding a first heat pipe and a second heat pipe at the bottom of the stator slot and the stator yoke respectively, the heat-conducting component can dissipate the combined heat from the windings and the stator core. Simultaneously, the heat pipes adopt a flat plate structure and are tightly fitted to the heating components, significantly reducing contact thermal resistance and achieving high thermal conductivity within a limited installation space. One end of the second heat pipe is embedded in the stator yoke, and the other end is embedded in the housing, forming a high-efficiency liquid cooling path with the external water jacket. This ensures heat dissipation performance while avoiding interference with the main magnetic circuit or causing additional eddy current losses, thereby achieving uniform temperature distribution inside the motor without sacrificing electromagnetic performance.

Description

Technical Field

[0001] This invention relates to the field of permanent magnet motor technology, and in particular to a cooling device for a permanent magnet motor. Background Technology

[0002] Permanent magnet motors, due to their high efficiency, high power density, and excellent dynamic performance, have been widely used in high-performance fields highly sensitive to space and weight, such as aerospace electric propulsion and electric vehicle hub drives. As motors develop towards higher speeds and greater power densities, the copper losses in their internal windings and the iron losses in the stator core increase significantly, leading to severe localized temperature rises. If heat dissipation is not timely and effective, this can cause risks such as permanent magnet demagnetization, insulation aging, and even structural failure. Currently, common motor cooling methods include air cooling, liquid cooling, and heat pipe-assisted cooling. Among these, heat pipes, with their high thermal conductivity, lack of moving parts, and passive operation, show promising application prospects in motor thermal management.

[0003] However, traditional heat pipe cooling structures often only provide localized enhanced heat dissipation for a single heat-generating area in the end winding or slot winding, making it difficult to simultaneously address the synergistic cooling needs of the stator core and windings, the two main heat sources. Furthermore, in motor layouts with limited space and height, conventional heat pipes, due to limitations in cross-sectional shape and installation methods, cannot achieve a tight fit with the core and windings, resulting in high contact thermal resistance and low heat transfer efficiency. Additionally, improper heat pipe placement can interfere with the main magnetic circuit or introduce additional eddy current losses, affecting the motor's electromagnetic performance.

[0004] Based on the above problems, we propose a cooling device for permanent magnet motors. Summary of the Invention

[0005] Therefore, the technical problem to be solved by this invention is: how to synchronously and efficiently remove the combined heat of the stator winding and core of a permanent magnet motor under space-constrained conditions, so as to achieve high power density motor thermal management with uniform temperature distribution, excellent heat dissipation performance and no impact on electromagnetic performance.

[0006] The above-mentioned technical problems are solved by the following technical solution: The present invention proposes a permanent magnet motor cooling device, which includes a heating component, a heat-conducting component disposed on the outer wall of the heating component, and a heat dissipation component disposed outside the heat-conducting component; the heating component includes a stator core and a winding disposed on the inner wall of the stator core; the stator core and the winding transfer heat to the heat dissipation component through the heat-conducting component.

[0007] In a preferred embodiment of the permanent magnet motor cooling device of the present invention: the stator core includes stator teeth, a stator slot is provided between two adjacent stator teeth, and a stator yoke is provided on the outer wall of the stator teeth.

[0008] In a preferred embodiment of the permanent magnet motor cooling device of the present invention: a positioning groove is provided on the outer wall of the stator slot, and a plurality of receiving grooves are provided on the outer wall of the stator yoke away from the stator teeth.

[0009] In a preferred embodiment of the permanent magnet motor cooling device of the present invention: the heat-conducting component includes a first heat pipe embedded in the positioning groove, and a second heat pipe is embedded in the receiving groove.

[0010] In a preferred embodiment of the permanent magnet motor cooling device of the present invention: the outer wall of the first heat pipe on the side away from the positioning groove is in contact with the winding.

[0011] In a preferred embodiment of the permanent magnet motor cooling device of the present invention: the outer wall of the stator core is provided with a housing, and half of the second heat pipe is embedded in the receiving groove, and the other half is embedded in the inner wall of the housing.

[0012] In a preferred embodiment of the permanent magnet motor cooling device of the present invention: the heat dissipation component includes a water jacket disposed outside the second heat pipe, and the outer wall of the water jacket is provided with a water inlet and a water outlet.

[0013] In a preferred embodiment of the permanent magnet motor cooling device of the present invention: one end of the housing is provided with a front end cover and the other end is provided with a rear end cover.

[0014] In a preferred embodiment of the permanent magnet motor cooling device of the present invention: one end of the first heat pipe and the second heat pipe extends from the stator core toward the water jacket.

[0015] In a preferred embodiment of the permanent magnet motor cooling device of the present invention: a bearing assembly is provided inside the stator core, a magnet is provided outside the bearing assembly, and a carbon fiber sheath is provided on the outer wall of the magnet.

[0016] The beneficial effects of this invention are as follows: by setting embedded first heat pipes and second heat pipes in the stator slot bottom and stator yoke respectively, the heat conduction components can simultaneously and efficiently dissipate the combined heat from the windings and stator core; at the same time, the heat pipes adopt a flat plate structure and are closely attached to the heating components, significantly reducing contact thermal resistance and achieving high thermal conductivity within a limited installation space; one end of the second heat pipe is embedded in the stator yoke and the other end is embedded in the housing, forming an efficient liquid cooling path with the external water jacket, which not only ensures heat dissipation performance but also avoids interference with the main magnetic circuit or causing additional eddy current losses. Thus, without sacrificing electromagnetic performance, it achieves efficient cooling of the motor with uniform internal temperature distribution, compact structure, and suitability for high power density permanent magnet motors. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments of the present invention will be briefly described below. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention. Wherein: Figure 1 An exploded view of the overall structure of the permanent magnet motor cooling device is shown. Figure 2 A cross-sectional view of the internal structure of the permanent magnet motor cooling device is shown. Figure 3 A schematic diagram of the connection structure between the heating element and the heat-conducting element is shown; Figure 4 A schematic diagram of the stator core structure is shown; Figure 5 A two-dimensional structural topology diagram of the first heat pipe and the second heat pipe is shown. Detailed Implementation

[0018] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0019] The terminology used in this invention is that which is currently widely used in the art in consideration of the function of the invention; however, these terms may vary according to the intent of those skilled in the art, precedent, or new technology in the art. Furthermore, specific terms may be chosen by the applicant, and in such cases, their detailed meanings will be described in the detailed description of the invention. Therefore, the terms used in this specification should not be construed as simple names, but rather based on their meanings and the overall description of the invention.

[0020] Reference Figures 1-5 This embodiment provides a permanent magnet motor cooling device, including a heating component 1, a heat-conducting component 2 disposed on the outer wall of the heating component 1, and a heat dissipation component 3 disposed outside the heat-conducting component 2. The heating component 1 consists of a stator core 11 and windings 12 embedded in its inner wall, serving as the main heat source and generating iron losses and copper losses respectively during motor operation. The stator core 11 and windings 12 transfer heat to the heat dissipation component 3 through the heat-conducting component 2. The heat-conducting component 2 adopts a flat plate structure to increase the contact area with the heating component 1, and effectively reduces the contact thermal resistance by tightly fitting and filling with heat-conducting interface material, thereby achieving synchronous and efficient heat conduction to the windings 12 and the stator core 11. The heat dissipation component 3 quickly removes the heat transferred from the heat-conducting component 2 through circulating coolant.

[0021] In one embodiment provided in this application, the stator core 11 includes a plurality of stator teeth 111 evenly distributed along the circumference. A stator slot 112 for embedding the winding 12 is formed between two adjacent stator teeth 111. The outer ends of the stator teeth 111 are connected to a stator yoke 113 forming an annular structure. The stator yoke 113 serves as part of the magnetic circuit for conducting the main magnetic flux and also provides installation space for the second heat pipe 22 in the heat conduction assembly 2. Thus, while ensuring electromagnetic performance, the heat of the stator core 11 body is effectively discharged.

[0022] In one embodiment provided in this application, a positioning groove 114 is provided on the outer wall of the stator slot 112 for embedding the first heat pipe 21 so that it is close to the bottom of the winding 12 to achieve efficient heat dissipation from the winding 12 in the slot; a plurality of circumferentially distributed receiving grooves 115 are provided on the outer wall of the stator yoke 113 away from the stator teeth 111 for embedding the second heat pipe 22 to directly absorb the iron loss heat in the yoke region of the stator core 11.

[0023] In one embodiment provided in this application, the heat-conducting component 2 includes a first heat pipe 21 embedded in the positioning groove 114 and a second heat pipe 22 embedded in the receiving groove 115. The first heat pipe 21 is close to the bottom of the stator slot 112 and forms good thermal contact with the winding 12 inside it, so as to efficiently dissipate the heat generated by the copper loss of the winding. The second heat pipe 22 is arranged circumferentially along the stator yoke 113 and directly absorbs the heat generated by the iron loss of the stator core 11. Circular heat pipes occupy too much radial space, and elliptical heat pipes are difficult to process. In this application, both sets of heat pipes preferably adopt a flat plate structure to maximize the contact area with the heat-generating components in a limited space, and achieve precise positioning and low thermal resistance heat transfer through embedded installation.

[0024] In one embodiment provided in this application, the outer wall of the first heat pipe 21 on the side away from the positioning groove 114 is in contact with the winding 12, so that the first heat pipe 21 can directly contact and efficiently absorb the copper loss heat generated by the winding 12 during operation; the outer surface of the evaporation section of the first heat pipe 21 is wrapped with polyimide insulating tape to ensure electrical insulation safety; the micro gaps at the contact point between the first heat pipe 21 and the winding 12 can be filled with thermally conductive silicone grease or potting compound to reduce contact thermal resistance.

[0025] In one embodiment provided in this application, the outer surface of the evaporation section of the second heat pipe 22 is wrapped with polyimide insulating tape to ensure electrical insulation safety. During installation, thermally conductive silicone grease or potting compound is uniformly applied to the outer surface of the evaporation section of the second heat pipe 22 to fill gaps and improve thermal conductivity. The outer wall of the stator core 11 is provided with a housing 13, which is made of low-density structural material, such as aluminum alloy or magnesium alloy. Half of the second heat pipe 22 is embedded in the receiving groove 115, and the other half is embedded in the inner wall of the housing 13. The semi-embedded structure not only ensures the reliable positioning and good heat conduction path of the second heat pipe 22 between the stator core 11 and the housing 13, but also effectively reduces the weakening of the magnetic circuit cross-sectional area of ​​the stator yoke 113, avoiding uneven magnetic flux distribution or core saturation due to excessively deep slots. At the same time, the housing 13 is used as a heat conduction medium to efficiently transfer heat to the external heat dissipation component 3, thereby improving the overall heat dissipation efficiency and structural compactness while ensuring the electromagnetic performance of the motor.

[0026] In one embodiment provided in this application, the heat dissipation assembly 3 includes a water jacket 31 disposed outside the second heat pipe 22. The water jacket 31 is arranged around the condensation section of the first heat pipe 21 and the second heat pipe 22, and is used to efficiently remove the heat conducted by the first heat pipe 21 and the second heat pipe 22 through forced convection cooling. The outer wall of the water jacket 31 is provided with an inlet 32 ​​and an outlet 33, which are used to introduce low-temperature coolant and discharge the heated coolant, respectively, thereby forming a continuous liquid cooling circulation loop. This ensures that the condensation section of the first heat pipe 21 and the second heat pipe 22 is in a stable low-temperature environment, improves its phase change heat transfer efficiency, and can also quickly conduct the combined heat generated by the stator core 11 and the winding 12 to the outside of the motor, effectively controlling the internal temperature rise of the motor.

[0027] In one embodiment provided in this application, the housing 13 has a front cover 131 at one end and a rear cover 132 at the other end. The front cover 131 and the rear cover 132 are respectively connected to the housing 13 by fasteners, forming a closed motor cavity for fixing the stator assembly, supporting the rotor bearing and protecting the internal structure from the influence of the external environment. The front cover 131 is installed in conjunction with the water jacket 31 to provide a stable installation reference and sealing environment for the condensation section of the first heat pipe 21 and the second heat pipe 22, ensuring that the coolant circulates efficiently in the water jacket 31 without leakage.

[0028] In one embodiment provided in this application, one end of the first heat pipe 21 and the second heat pipe 22 extends from the stator core 11 toward the water jacket 31, such that the evaporation section of the first heat pipe 21 and the second heat pipe 22 is located in the heating area of ​​the stator slot 112 or the stator yoke 113, and the condensation section of the first heat pipe 21 and the second heat pipe 22 extends through the front end cover 131 into the interior of the water jacket 31.

[0029] In one embodiment provided in this application, a bearing assembly 14 is provided inside the stator core 11 to support the motor rotor and ensure its rotational accuracy; a magnet 15 is coaxially arranged outside the bearing assembly 14 to form the rotor part of the permanent magnet motor and to generate a stable main magnetic field; the outer wall of the magnet 15 is covered with a carbon fiber sheath 16, which is formed by winding and curing high-strength carbon fiber material. This not only effectively restrains the risk of radial displacement or cracking of the magnet 15 due to centrifugal force during high-speed rotation, but also has low density, high rigidity and non-conductive characteristics, which can avoid eddy current loss and reduce rotor weight, thereby improving the high-speed operation stability and overall efficiency of the motor.

[0030] In use, firstly, polyimide insulating tape is wrapped around the outer surface of the evaporation sections of the first heat pipe 21 and the second heat pipe 22 to ensure electrical insulation safety. The first heat pipe 21 is then embedded in the positioning groove 114 at the bottom of the stator slot 112 of the stator core 11, ensuring its outer wall is tightly fitted to the winding 12. Thermally conductive silicone grease is then evenly applied to the surface of the first heat pipe 21 to fill gaps and improve thermal conductivity. Simultaneously, the second heat pipe 22 is embedded in the receiving groove 115 of the stator yoke 113, with its other half embedded in the inner wall of the housing 13. Thermally conductive silicone grease is also evenly applied to the surface of the second heat pipe 22 to fill gaps and improve thermal conductivity, thus achieving a thermal bridge connection between the stator core 11 and the housing 13. Furthermore, a water jacket 31 is fitted over the condenser section of the second heat pipe 22. The motor is connected to an external circulating cooling system through an inlet 32 ​​and an outlet 33. During motor operation, the copper loss heat generated by the winding 12 and the iron loss heat generated by the stator core 11 are efficiently absorbed by the evaporation sections of the first heat pipe 21 and the second heat pipe 22, respectively. The heat is then transferred to the condensation section through the internal working fluid phase change, and then carried away by the coolant in the water jacket 31, thereby achieving coordinated and uniform cooling of the winding 12 and the stator core 11. The front cover 131 and the rear cover 132 seal the motor cavity to ensure structural stability and operational safety. This effectively controls the motor temperature rise without interfering with the main magnetic circuit or introducing significant eddy current losses, making it suitable for space-constrained and high-power-density applications such as aerospace electric propulsion and electric vehicle hub drive.

[0031] Finally, it should be noted that the methods and devices described in detail above are merely embodiments, and those skilled in the art can modify these embodiments in different ways as long as they do not depart from the scope of the present invention.

Claims

1. A cooling device for a permanent magnet motor, characterized in that: include, Heating component (1), heat-conducting component (2) disposed on the outer wall of the heating component (1), and heat dissipation component (3) disposed outside the heat-conducting component (2). The heating component (1) includes a stator core (11) and a winding (12) disposed on the inner wall of the stator core (11). The stator core (11) and the winding (12) transfer heat to the heat dissipation component (3) through the heat-conducting component (2).

2. The permanent magnet motor cooling device according to claim 1, characterized in that: The stator core (11) includes stator teeth (111), and stator slots (112) are provided between two adjacent stator teeth (111). The outer wall of the stator teeth (111) is provided with stator yokes (113).

3. The permanent magnet motor cooling device according to claim 2, characterized in that: The stator slot (112) has a positioning groove (114) on its outer wall, and the stator yoke (113) has a plurality of receiving grooves (115) on its outer wall away from the stator tooth (111).

4. The permanent magnet motor cooling device according to claim 3, characterized in that: The heat-conducting component (2) includes a first heat pipe (21) embedded in the positioning groove (114) and a second heat pipe (22) embedded in the receiving groove (115).

5. The permanent magnet motor cooling device according to claim 4, characterized in that: The outer wall of the first heat pipe (21) on the side away from the positioning groove (114) is in contact with the winding (12).

6. The permanent magnet motor cooling device according to claim 4 or 5, characterized in that: The stator core (11) has a housing (13) on its outer wall. Half of the second heat pipe (22) is embedded in the receiving groove (115), and the other half is embedded in the inner wall of the housing (13).

7. The permanent magnet motor cooling device according to claim 6, characterized in that: The heat dissipation assembly (3) includes a water jacket (31) disposed outside the second heat pipe (22), and the outer wall of the water jacket (31) is provided with an inlet (32) and an outlet (33).

8. The permanent magnet motor cooling device according to claim 7, characterized in that: The housing (13) has a front cover (131) at one end and a rear cover (132) at the other end.

9. The permanent magnet motor cooling device according to claim 7 or 8, characterized in that: One end of the first heat pipe (21) and the second heat pipe (22) extends from the stator core (11) toward the water jacket (31).

10. The permanent magnet motor cooling device according to claim 9, characterized in that: The stator core (11) is provided with a bearing assembly (14) inside, and a magnet (15) is provided outside the bearing assembly (14). The outer wall of the magnet (15) is provided with a carbon fiber sheath (16).

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