A water cooling device for permanent magnet synchronous motor rotor

Abstract

The present invention relates to the technical field of cooling equipment, and specifically to a water cooling device for a permanent magnet synchronous motor rotor, the water cooling device comprises a central shaft cooling assembly, the central shaft cooling assembly comprises a central shaft, a water tank drum and a water tank cover, the center of the rear part of the rotating shaft is hollowed out, the rear end cover and the rear end of the rotating shaft form a rear end sealing cavity, the central shaft is installed in the central hollow of the rotating shaft and forms a labyrinth seal with the rotating shaft, the other end is fixedly connected with the water tank drum with a water seal, the water tank drum and the water tank cover are sealed and fixedly connected to form an inner cavity, the hollow of the central shaft is connected with the inner cavity, the water tank drum is fixedly connected with the rear end cover, the bottom of the shell is processed with a cooling water inlet, the top is processed with a cooling water outlet, and the rear end cover is processed with a built-in pipe connecting the cooling water inlet with the water tank drum and a built-in pipe connecting the rear end sealing cavity with the cooling water outlet. The beneficial technical effects of the present invention include: it is easy to realize dynamic sealing connection, the cooling flow channel passes through the rotating shaft and the rotor core, and has a better heat dissipation effect.

Description

Technical Field

[0001] The invention relates to the technical field of cooling equipment, and in particular to a water cooling device for a permanent magnet synchronous motor rotor. Background Art

[0002] With the continuous advancement of new energy vehicles, the speed requirements for the drive motors are constantly increasing. Due to the eddy current effect, the temperature of the motor rotor will be very high. If it is not cooled, it may cause magnetic steel demagnetization, bearing failure, rotor deformation and other faults. The cooling form of traditional motor rotors mainly relies on their own thermal radiation cooling, which has a very low cooling efficiency. Other rotors that use oil cooling often need to be matched with other materials such as enameled wire to be oil-resistant, and can only be used for oil-cooled motors, but not for water-cooled motors.

[0003] Among the existing disclosed technologies, the rotor water cooling structures disclosed in patents CN201520349861 and CN201621177775 mainly rely on the water path formed by the central cooling water pipe and the rotating shaft to achieve rotor cooling. However, since the cooling water only passes through the rotating shaft, the cooling effect of this solution is poor.

[0004] Patent CN201921098817 opens a spiral channel in the rotor body for cooling, but since the permanent magnet synchronous motor is stacked in sections, it cannot form a spiral shape. At the same time, since the water inlet and outlet described in the patent are both rotating, it is difficult to achieve sealing in the automotive permanent magnet synchronous motor.

[0005] Patent CN202221136058 introduces a method of cooling by setting an annular water pipe in the rotor. However, on the one hand, this solution increases the weight of the rotor due to the additional water pipe, and on the other hand, the gap between the water pipe and the rotor will reduce the efficiency of heat exchange.

[0006] Therefore, it is still necessary to study the cooling technology of motor rotor. Summary of the invention

[0007] The technical problem to be solved by the present invention is that the current water cooling device for the motor rotor has the technical problem of poor cooling effect or low sealing reliability. A water cooling device for the rotor of a permanent magnet synchronous motor is proposed, which has a faster cooling effect and is easy to seal.

[0008] In order to solve the above technical problems, the present invention adopts the following technical scheme: a water cooling device for a permanent magnet synchronous motor rotor, the permanent magnet synchronous motor comprises a rotating shaft, a rotor core assembly, two rotor end plates, a front end cover, a rear end cover and a shell, the rotor core assembly is coaxially fixedly connected to the rotating shaft, the two ends of the rotor core assembly are fixedly connected to the rotor end plates, the two rotor end plates and the two ends of the rotor core assembly have gaps, the rotor core assembly is processed with a through hole connecting the two gaps, the rotating shaft is installed on the shell through the front end cover and the rear end cover, the water cooling device comprises a central shaft cooling assembly, the central shaft cooling assembly comprises a central shaft, a water trough drum and a water trough cover, the center of the rear part of the rotating shaft has a hollow, the rear end cover is rotatably connected to the rotating shaft, and the rear end cover and the rear end of the rotating shaft form a rear end seal The cavity, the rotating shaft is processed with a small hole connected with the two gaps, the central shaft is fixedly installed in the central hollow of the rotating shaft, the central shaft is hollow, one end of the central shaft is rotatably connected with the inner wall of the central hollow of the rotating shaft and forms a labyrinth seal, the other end of the central shaft is fixedly connected with the water tank drum with a water seal, the water tank drum and the water tank cover are sealed and fixedly connected to form an inner cavity, the hollow of the central shaft is connected with the inner cavity, the water tank drum is fixedly connected with the rear end cover, the bottom of the shell is processed with a cooling water inlet, the top of the shell is processed with a cooling water outlet, the rear end cover is processed with an internal pipe connecting the cooling water inlet with the water tank drum and an internal pipe connecting the rear end sealing cavity with the cooling water outlet, and the cooling water inlet and the cooling water outlet are connected with the cooling water channel of the permanent magnet synchronous motor. Only one end of the central shaft is rotatably connected with the rotating shaft, and the central shaft forms a labyrinth seal with the inner wall of the rotating shaft. The cooling path flows through the rotating shaft and the rotor core assembly, and the cooling effect is excellent.

[0009] Preferably, the rotor core assembly comprises a rotor core, a plurality of magnetic steels are distributed throughout the rotor core, and the plurality of magnetic steels are fixed by magnetic steel fixing injection molding material.

[0010] Preferably, the inner wall of the through hole is covered with water channel injection plastic.

[0011] Preferably, an end plate sealing ring is installed between the rotating shaft and the rotor end plate.

[0012] Preferably, an end plate plane seal is installed between the rotor core assembly and the rotor end plate.

[0013] Preferably, the end surface of the rotor end plate is processed with an end plate sealing ring mounting portion, a radial water channel, a circumferential water channel and an end plate plane sealing mounting portion, the end plate sealing ring mounting portion corresponds to the end plate plane sealing position, the circumferential water channel covers the through hole, the radial water channel connects the circumferential water channel with the gap, and the end plate sealing ring mounting portion is used to install the end plate sealing ring between the rotating shaft and the rotor end plate.

[0014] Preferably, a labyrinth sealing protrusion structure is provided between the outer wall of the central shaft and the hollow inner wall at the center of the rotating shaft.

[0015] Preferably, an inlet temperature sensor and an outlet temperature sensor are respectively provided at the cooling water inlet and the cooling water outlet, and the inlet temperature sensor and the outlet temperature sensor detect the water temperature at the cooling water inlet and the cooling water outlet respectively. The water cooling device also includes a controller, and the inlet temperature sensor and the outlet temperature sensor are both connected to the controller.

[0016] Preferably, the water cooling device further comprises an ultrasonic sound wave generator, and the ultrasonic sound wave generator is mounted on the water tank drum.

[0017] Preferably, the ultrasonic sound wave generator includes an end cover, a sealing mounting ring, a spring and a vibration plate, the sealing mounting ring is installed on the water tank drum, the side of the sealing mounting ring is sealed and connected to the water tank drum, the end cover closes one end of the sealing mounting ring, the first end of the spring is fixedly connected to the end cover, the vibration plate is installed in the water tank drum, the outer edge of the vibration plate abuts against the inner wall of the water tank drum, the second end of the spring is fixedly connected to the vibration plate, the two ends of the spring are connected in series to an electronic switch and a power supply through wires, and the control end of the electronic switch is connected to a controller.

[0018] The beneficial technical effects of the present invention include: dynamic connection is achieved through the water trough drum and the center shaft with the rotating shaft, the installation position of the water trough drum is easy to achieve dynamic sealing connection, the cooling flow channel passes through the rotating shaft and the rotor core, the coolant and the rotor core can be in direct contact, ensuring the heat dissipation effect of the rotor; by flowing cooling water from the rotating shaft, the heat of the rotating shaft can be better absorbed to improve the cooling effect; the structural reliability is good, and the cooling water inside the rotor will not leak into the inside of the motor to cause insulation failure; the structure is compact, and it is particularly suitable for occasions with limited installation space.

[0019] Other features and advantages of the present invention will be disclosed in detail in the following specific embodiments and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be further described below in conjunction with the accompanying drawings:

[0021] Figure 1The figure is a schematic diagram of the rotor structure of a permanent magnet synchronous motor according to an embodiment of the present invention.

[0022] Figure 2 This is a schematic diagram of the installation of the central shaft and the water tank drum in Example 1 of the present invention.

[0023] Figure 3 This is a schematic diagram of the central axis structure of Embodiment 1 of the present invention.

[0024] Figure 4 It is a schematic structural diagram of a rotor core assembly according to an embodiment of the present invention.

[0025] Figure 5 This is a schematic diagram of the rotor end plate structure according to an embodiment of the present invention.

[0026] Figure 6 This is a schematic diagram of the central axis structure of the second embodiment of the present invention.

[0027] Wherein: 1. central shaft cooling assembly, 2. water seal, 3. end plate sealing ring, 4. rotor end plate, 5. rotor core assembly, 6. end plate plane sealing, 7. rotating shaft, 8. cooling water inlet, 9. cooling water path, 10. cooling water outlet, 11. central shaft, 12. water tank drum, 13. water tank cover, 41. end plate sealing ring mounting part, 42. radial water channel, 43. circumferential water channel, 44. end plate plane sealing mounting part, 51. rotor core, 52. magnet, 53. magnet fixing injection plastic, 54. water channel injection plastic, 111. water channel, 112. labyrinth sealing protrusion, 131. end cover, 132. sealing mounting ring, 133. spring, 134. vibration plate. DETAILED DESCRIPTION

[0028] The technical solutions of the embodiments of the present invention are explained and described below in conjunction with the drawings of the embodiments of the present invention, but the following embodiments are only preferred embodiments of the present invention, not all. Based on the embodiments in the implementation mode, other embodiments obtained by those skilled in the art without creative work are all within the protection scope of the present invention.

[0029] In the following description, terms such as "inside", "outside", "up", "down", "left", "right", etc. that indicate directions or positional relationships are only used to facilitate the description of the embodiments and simplify the description, and do not indicate or imply that the referred device or element must have a specific direction, be constructed and operate in a specific direction. Therefore, it should not be understood as a limitation of the present invention.

[0030] Embodiment 1:

[0031] A water cooling device for a permanent magnet synchronous motor rotor, see the attached Figure 1The permanent magnet synchronous motor includes a rotating shaft 7, a rotor core assembly 5, two rotor end plates 4, a front cover, a rear cover and a housing. The two ends of the rotor core assembly 5 are fixedly connected to the rotating shaft 7 through the rotor end plates 4. There are gaps between the two rotor end plates 4 and the two ends of the rotor core 51 group. The rotor core 51 group is processed with a through hole connecting the two gaps. The rotating shaft 7 is installed on the housing through the front cover and the rear cover. The water cooling device includes a central shaft cooling assembly 1. Please refer to the attached Figure 2 and attached Figure 3 The central shaft cooling assembly 1 includes a central shaft 11, a water tank drum 12 and a water tank cover 13. The center of the rear part of the rotating shaft 7 is hollowed out. The rear end cover is rotatably connected to the rotating shaft 7, and a rear end sealing cavity is formed between the rear end cover and the rear end of the rotating shaft 7. A water seal 2 is provided between the rear end cover and the rotating shaft 7. The rotating shaft 7 is processed with two communicating small holes connected to the gap. The central shaft 11 is fixedly installed in the central hollow of the rotating shaft 7. The central shaft 11 is hollow and tubular. One end of the central shaft 11 is rotatably connected to the inner wall of the central hollow of the rotating shaft 7 to form a labyrinth seal. The central shaft 1 1 The other end is fixedly connected with the water tank drum 12 in a water-tight manner. The water tank drum 12 and the water tank cover 13 are fixedly connected and form an inner cavity. The hollow of the central shaft 11 is connected with the inner cavity. The water tank drum 12 is fixedly connected with the rear end cover. The bottom of the shell is processed with a cooling water inlet 8, the top of the shell is processed with a cooling water outlet 10, and the rear end cover is processed with an internal pipe connecting the cooling water inlet 8 with the water tank drum 12 and an internal pipe connecting the rear end sealed cavity with the cooling water outlet 10. The cooling water inlet 8 and the cooling water outlet 10 are connected with the cooling water channel of the permanent magnet synchronous motor. Only one end of the central shaft 11 is rotatably connected with the rotating shaft 7, and a labyrinth seal is formed between the central shaft 11 and the inner wall of the rotating shaft 7. The cooling water path 9 flows through the rotating shaft 7 and the rotor core assembly 5, and the cooling effect is excellent.

[0032] The cooling water of the casing enters the water trough drum 12 of the central shaft cooling assembly 1 through the water channel on the end cover. The water trough drum 12 and the water trough cover 13 form a seal. The cooling water enters the central shaft 11 of the central shaft cooling assembly 1, and enters the gap between the rotor end plate 4 and the rotor core assembly 5 through the radial opening of the rotating shaft 7, and then enters the middle hole of the water channel injection plastic 54 in the rotor core assembly 5, thereby flowing through the rotor core, and the heat generated by the rotor core is taken away by the coolant; and passes through the gap between the right rotor end plate 4 and the rotor core assembly 5, enters the gap formed by the rotating shaft 7 and the central shaft 11, and finally flows into the rear end cover; the rear end cover and the main cavity of the motor are separated by a water seal 2 to ensure the sealing of the motor; finally, the coolant returns to the water channel outlet of the casing through the rear end cover. The central shaft cooling assembly consists of a central shaft 11, a water trough drum 12, and a water trough cover 13, wherein the water trough drum 12 has a small hole radially opened for the coolant to enter; a labyrinth seal is formed between the rotating shaft 7 and the central shaft 11, and a seal exists between the water trough drum 12 and the water trough cover 13, thereby ensuring that the coolant flows out from the water channel 111 of the central shaft 11 without causing other leakage.

[0033] Please refer to the attached Figure 4 The rotor core assembly 5 includes a rotor core 51, and a plurality of magnetic steels 52 are distributed throughout the rotor core 51. The plurality of magnetic steels 52 are fixed by magnetic steel fixing injection plastic 53. The rotor core 51 is processed with a through hole along the axial direction of the rotating shaft 7, and both ends of the through hole are connected to the gap. Among them, the inner wall of the through hole is covered by a water channel injection plastic 54. An end plate sealing ring 3 is installed between the rotating shaft 7 and the rotor end plate 4. An end plate plane seal 6 is installed between the rotor core assembly 5 and the rotor end plate 4. The rotor core assembly 5 includes a rotor core 51, a magnetic steel 52, a magnetic steel fixing injection plastic 53 and a water channel injection plastic 54. From a process point of view, the rotor core 51 is formed by laminating thin sheets, and after laminating, the magnetic steel 52 is inserted, and the magnetic steel fixing injection plastic 53 and the water channel injection plastic 54 are integrally injected, wherein the water channel injection plastic 54 is a hollow structure for cooling water to flow through, and the water channel injection plastic 54 is used to isolate the cooling water and the rotor core 51 to ensure that the cooling water does not leak.

[0034] Please refer to the attached Figure 5 The end surface of the rotor end plate 4 is processed with an end plate sealing ring mounting portion 41, a radial water channel 42, a circumferential water channel 43 and an end plate plane sealing mounting portion 44. The end plate sealing ring mounting portion 41 corresponds to the position of the end plate plane seal 6. The circumferential water channel 43 covers the through hole. The radial water channel 42 connects the circumferential water channel 43 with the gap. The end plate sealing ring mounting portion 41 is used to install the end plate sealing ring 3 between the rotating shaft 7 and the rotor end plate 4.

[0035] There is a labyrinth seal protrusion 112 structure between the outer wall of the central shaft 11 and the hollow inner wall at the center of the rotating shaft 7. The labyrinth seal protrusion 112 of the central shaft 11 forms a small gap with the central hole of the rotating shaft 7. When the rotating shaft 7 and the central shaft 11 rotate relative to each other, the air pressure formed between them is used to seal.

[0036] An inlet temperature sensor and an outlet temperature sensor are respectively provided at the cooling water inlet 8 and the cooling water outlet 10, and the inlet temperature sensor and the outlet temperature sensor detect the water temperature at the cooling water inlet 8 and the cooling water outlet 10 respectively. The water cooling device also includes a controller, and the inlet temperature sensor and the outlet temperature sensor are both connected to the controller.

[0037] Please refer to the attached Figure 6The water cooling device also includes an ultrasonic sound wave generator, which is installed on the water tank drum 12. The ultrasonic sound wave generator includes an end cover 131, a sealing mounting ring 132, a spring 133 and a vibration plate 134. The sealing mounting ring 132 is installed on the water tank drum 12, and the side of the sealing mounting ring 132 is sealed and connected to the water tank drum 12. The end cover 131 closes one end of the sealing mounting ring 132. The first end of the spring 133 is fixedly connected to the end cover 131. The vibration plate 134 is installed in the water tank drum 12, and the outer edge of the vibration plate 134 abuts against the inner wall of the water tank drum 12. The second end of the spring 133 is fixedly connected to the vibration plate 134. The two ends of the spring 133 are connected in series with an electronic switch and a power supply through a wire, and the control end of the electronic switch is connected to the controller. After the spring 133 is energized, it will shrink. The electronic switch is controlled to be turned on and off at a predetermined frequency, so that the spring 133 can generate a vibration of a preset frequency, thereby driving the vibration plate 134 to generate ultrasonic vibration. Prior art [1] Duan Xili, Wang Xuanying, Wang Gang, et al. Effect of ultrasonic vibration on heat transfer and pressure drop in heat exchanger tubes [J]. Petrochemical Equipment, 2004 (1): 1-4. It is recorded that by generating ultrasonic vibration in the cooling water flow, the cavitation effect generated by the ultrasonic vibration destroys the laminar boundary layer, significantly improves the heat transfer coefficient, and reduces the pressure drop in the tube. This solution can further improve the cooling effect of the motor rotor by improving the water tank drum structure to inject ultrasonic waves into the cooling water.

[0038] The beneficial technical effects of this embodiment include: a dynamic connection is achieved with the rotating shaft 7 through the central shaft 11, the installation position of the water tank drum 12 is easy to achieve a dynamic sealing connection, and the cooling flow channel passes through the rotating shaft 7 and the rotor core 51, which has a better heat dissipation effect; by flowing cooling water from the rotating shaft 7, the heat of the rotating shaft 7 can be better absorbed, thereby improving the cooling effect.

[0039] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that the present invention includes but is not limited to the contents described in the drawings and the above specific embodiments. Any modification that does not deviate from the functional and structural principles of the present invention will be included in the scope of the claims.

Claims

1. A water cooling device for a permanent magnet synchronous motor rotor, the permanent magnet synchronous motor comprising a rotating shaft (7), a rotor core assembly (5), two rotor end plates (4), a front end cover, a rear end cover and a housing, the rotor core assembly (5) is coaxially fixedly connected to the rotating shaft (7), both ends of the rotor core assembly (5) are fixedly connected to the rotor end plates (4), the two rotor end plates (4) and both ends of the rotor core assembly (5) have gaps, the rotor core assembly (5) is processed with a through hole connecting the two gaps, the rotating shaft (7) is installed on the housing through the front end cover and the rear end cover, characterized in that The water cooling device comprises a central shaft cooling assembly (1), wherein the central shaft cooling assembly (1) comprises a central shaft (11), a water tank drum (12) and a water tank cover (13); the center of the rear part of the rotating shaft (7) is hollowed out; the rear end cover is rotatably connected to the rotating shaft (7); and a rear end sealing cavity is formed between the rear end cover and the rear end of the rotating shaft (7); the rotating shaft (7) is processed with two communicating small holes connected to the gap; the central shaft (11) is fixedly installed in the central hollow of the rotating shaft (7); the central shaft (11) is in a hollow tubular shape; one end of the central shaft (11) is rotatably connected to the inner wall of the central hollow of the rotating shaft (7); and the outer wall of the central shaft (11) is connected to the inner wall of the central hollow. A labyrinth sealing protrusion (112) structure is provided between the hollow inner walls at the center of the rotating shaft (7); the other end of the central shaft (11) is fixedly connected to the water tank drum (12) in a water-tight manner; the water tank drum (12) and the water tank cover (13) are sealed and fixedly connected to form an inner cavity; the hollow of the central shaft (11) is connected to the inner cavity; the water tank drum (12) is fixedly connected to the rear end cover; a cooling water inlet (8) is machined on the bottom of the shell; a cooling water outlet (10) is machined on the top of the shell; and the rear end cover is machined with an internal pipe connecting the cooling water inlet (8) and the water tank drum (12) and an internal pipe connecting the rear end sealing cavity and the cooling water outlet (10).

2. The water cooling device for a permanent magnet synchronous motor rotor according to claim 1, characterized in that: The rotor core assembly (5) comprises a rotor core (51), wherein a plurality of magnetic steels (52) are distributed throughout the rotor core (51), and the plurality of magnetic steels (52) are fixed by magnetic steel fixing injection molding material (53).

3. The water cooling device for a permanent magnet synchronous motor rotor according to claim 1, characterized in that: The inner wall of the through hole is covered by a water channel injection molding material (54).

4. A water cooling device for a permanent magnet synchronous motor rotor according to claim 2 or 3, characterized in that: An end plate sealing ring (3) is installed between the rotating shaft (7) and the rotor end plate (4).

5. A water cooling device for a permanent magnet synchronous motor rotor according to claim 2 or 3, characterized in that: An end plate plane seal (6) is installed between the rotor core assembly (5) and the rotor end plate (4).

6. The water cooling device for a permanent magnet synchronous motor rotor according to claim 5, characterized in that: The end surface of the rotor end plate (4) is processed with an end plate sealing ring installation portion (41), a radial water channel (42), a circumferential water channel (43) and an end plate plane sealing installation portion (44); the end plate sealing ring installation portion (41) corresponds to the position of the end plate plane seal (6); the circumferential water channel (43) covers the through hole; the radial water channel (42) connects the circumferential water channel (43) with the gap; and the end plate sealing ring installation portion (41) is used to install the end plate sealing ring (3) between the rotating shaft (7) and the rotor end plate (4).

7. A water cooling device for a permanent magnet synchronous motor rotor according to any one of claims 1 to 3, characterized in that: An inlet temperature sensor and an outlet temperature sensor are respectively provided at the cooling water inlet (8) and the cooling water outlet (10), and the inlet temperature sensor and the outlet temperature sensor respectively detect the water temperature at the cooling water inlet (8) and the cooling water outlet (10). The water cooling device also includes a controller, and the inlet temperature sensor and the outlet temperature sensor are both connected to the controller.

8. The water cooling device for a permanent magnet synchronous motor rotor according to claim 7, characterized in that: The water cooling device also includes an ultrasonic sound wave generator, which is installed on the water tank drum (12).

9. The water cooling device for a permanent magnet synchronous motor rotor according to claim 8, characterized in that: The ultrasonic sound wave generator comprises an end cover (131), a sealing mounting ring (132), a spring (133) and a vibration plate (134); the sealing mounting ring (132) is mounted on the water tank drum (12); the side surface of the sealing mounting ring (132) is sealedly connected to the water tank drum (12); the end cover (131) closes one end of the sealing mounting ring (132); the first end of the spring (133) is fixedly connected to the end cover (131); the vibration plate (134) is mounted in the water tank drum (12); the outer edge of the vibration plate (134) abuts against the inner wall of the water tank drum (12); the second end of the spring (133) is fixedly connected to the vibration plate (134); the two ends of the spring (133) are connected in series to an electronic switch and a power supply through a wire; and the control end of the electronic switch is connected to a controller.

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