A water cooling system for the rotor of a low-speed, high-torque permanent magnet synchronous motor

Abstract

This invention discloses an internal water channel cooling system for a low-speed, high-torque permanent magnet synchronous motor rotor. The system includes an internal water channel cooling device, a bearing, and a waterproofing device. The internal water channel cooling device is fixed to the inner wall of the rotor and rotates at the same speed as the rotor. The inner ring of the bearing is connected to the inlet end of the internal water channel cooling device, and the outer ring of the bearing is connected to the outlet end of the external water channel. Coolant flows from the external water channel along the gap in the middle of the inner ring of the bearing to the internal water channel cooling device. The connection between the water channels at both ends of the bearing is sealed off by the waterproofing device. This invention sets up internal water channels inside the motor and extends the flow path of the coolant within the channels using baffles, increasing the coolant flow distance and thus improving the cooling effect. This solves the problem of temperature rise in the permanent magnet part, which has the greatest impact on the performance of the permanent magnet synchronous motor, thereby improving the performance of the permanent magnet synchronous motor.

Description

Technical Field

[0001] This invention relates to motor cooling technology, and in particular to a water channel cooling system for the rotor of a low-speed, high-torque permanent magnet synchronous motor. Background Technology

[0002] Low-speed, high-torque permanent magnet synchronous motors can directly drive equipment, boast a high power factor, and maintain high efficiency within the 25%–120% rated load range, resulting in more significant energy savings under light loads. Simultaneously, the low operating speed and high output torque effectively solve the problem of difficult heavy-load equipment startup in heavy industrial production, ensuring overall system safety and stability. However, the high power density, high load capacity, and compact structure of low-speed, high-torque permanent magnet synchronous motors lead to higher loss density, exacerbating the problems of rapid heat generation and slow heat dissipation. Furthermore, these motors are primarily used in ports, coal mines, and other complex environments, where heat dissipation deteriorates, increasing the overall temperature rise of the motor. The insulating and magnetic materials used in the motor have specific operating temperature ranges; excessively high temperatures directly affect the motor's normal and stable operation, reducing its lifespan. Especially for permanent magnets, the performance of neodymium iron boron materials is significantly affected by temperature. When the motor temperature rises too high, it can cause irreversible demagnetization of the magnets, which in turn changes the internal magnetic field of the motor and affects the output performance. The motor temperature rise problem has become an important limiting factor restricting the further improvement of the performance of permanent magnet synchronous motors.

[0003] Existing water-cooling structures mainly include external channel types. External channel water-cooling systems design cooling water channels on the outer surface of the motor stator, allowing cooling water to flow through the motor via external channels. In the motor structure, the operating temperature of the permanent magnet has the most significant impact on motor performance. The aforementioned water-cooling structures, located outside the stator, can only achieve indirect heat dissipation for the permanent magnets; their effect on reducing the permanent magnet temperature and thus improving motor performance is not very significant. Summary of the Invention

[0004] Purpose of the invention: To address the above problems, the purpose of this invention is to provide an internal water cooling system for the rotor of a low-speed, high-torque permanent magnet synchronous motor.

[0005] Technical Solution: The present invention provides a low-speed, high-torque permanent magnet synchronous motor rotor internal water channel cooling system, wherein the permanent magnet synchronous motor includes a rotor component and a stator component. The rotor internal water channel cooling system includes an internal water channel cooling device, a bearing, and a waterproof device. The internal water channel cooling device is fixed to the inner wall of the rotor component and rotates with the rotor component at the same speed. The inner ring of the bearing is connected to the inlet end of the internal water channel cooling device, and the outer ring of the bearing is connected to the outlet end of the external water channel. The coolant flows from the external water channel along the gap in the middle of the inner ring of the bearing to the internal water channel cooling device. The water channel connection at both ends of the bearing forms a closed dead end through the waterproof device.

[0006] Furthermore, the internal water channel cooling device includes multiple rotor internal water channels, with adjacent rotor internal water channels spaced evenly and distributed uniformly along the circumferential direction of the rotating shaft.

[0007] Furthermore, a baffle is installed inside the rotor's internal water channel to allow the coolant to flow along a pre-defined flow path from the inlet to the outlet of the rotor's internal water channel.

[0008] Furthermore, the waterproofing device includes a first waterproof cover plate, a second waterproof cover plate, a first waterproof sealing ring, a second waterproof sealing ring, and a waterproof sleeve. The waterproof sleeve covers the outside of the bearing, and the inside of the bearing is provided with a waterproof coating. The second waterproof cover plate is annular, with its inner diameter being the same as the outer diameter of the bearing's inner ring and its outer diameter being the same as the outer diameter of the bearing's outer ring. The first waterproof cover plate is fixed at the water inlet end of the bearing, and the second waterproof cover plate and the bearing together form a closed dead end. The second waterproof cover plate and the first waterproof cover plate are connected by the first waterproof sealing ring. The first waterproof cover plate, the second waterproof cover plate, and the first waterproof sealing ring serve as the waterproofing device at the water inlet end of the bearing. The inner ring of the bearing is connected to the water inlet side of the inner water channel cooling device by the second waterproof sealing ring.

[0009] Furthermore, the cross-section of the water channel inside the rotor is fan-shaped and is fixed between the rotor aluminum block and the shaft.

[0010] Beneficial effects: Compared with the prior art, the significant advantages of this invention are:

[0011] 1. This invention addresses the internal heat dissipation problem of the rotor by setting up internal water channels inside the motor. By using baffles inside the internal water channels to lengthen the flow path of the coolant, the flow distance of the coolant is increased, thereby increasing the cooling effect. This solves the problem of temperature rise in the permanent magnet part, which has the greatest impact on the performance of the permanent magnet synchronous motor, thus improving the performance, efficiency, and operational reliability of the permanent magnet synchronous motor.

[0012] 2. The present invention provides a bearing at the interface of the inner and outer water channels, so that the inner and outer water channels can rotate relative to each other using the inner and outer rings of the bearing;

[0013] 3. The present invention provides waterproofing treatment on both sides of the bearing to ensure the sealing of the connection, thereby not affecting the operation of the motor. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the permanent magnet motor structure in the embodiment;

[0015] Figure 2 This is a longitudinal cross-sectional view of the permanent magnet motor in the embodiment;

[0016] Figure 3 This is an exploded view of the internal water cooling device and waterproofing device in the embodiment;

[0017] Figure 4 This is a cross-sectional view of the water channel section inside the rotor in the embodiment. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments.

[0019] This embodiment describes a water-cooling system for the rotor of a low-speed, high-torque permanent magnet synchronous motor. The permanent magnet synchronous motor includes a rotor and a stator. Figure 1 As shown, the rotor is fixed on the shaft 19 and rotates at the same speed as the shaft 19. The stator includes a stator core 15 and windings 22. An external water channel 16 is provided around the stator core 15 for heat dissipation from the outside of the motor. The internal water channel cooling system includes an internal water channel cooling device, a bearing 20, and a waterproof device. The internal water channel cooling device is used for direct heat dissipation from the inside of the rotor and the permanent magnets. The internal water channel cooling device is fixed to the inner wall of the rotor and rotates at the same speed as the rotor. The inner ring 32 of the bearing is connected to the inlet end of the internal water channel cooling device, and the outer ring 31 of the bearing is connected to the outlet end of the external water channel. Coolant flows from the external water channel along the gap in the middle of the inner ring 32 of the bearing to the internal water channel cooling device. The connection between the water channels at both ends of the bearing is sealed by the waterproof device.

[0020] like Figure 1 As shown, the rotor assembly includes a rotor core 17 and an aluminum block 14. The rotor core 17 is fixed to the inner wall of the permanent magnet, and the aluminum block 14 is fixed to the inner wall of the rotor core 17. An internal water cooling device is fixed to the inner wall of the aluminum block 14.

[0021] The internal water channel cooling device includes multiple rotor internal water channels 12, with adjacent rotor internal water channels 12 spaced evenly and distributed uniformly along the circumferential direction of the rotating shaft 19.

[0022] In one example, such as Figure 3 As shown, this embodiment includes 6 rotor internal water channels 12, which converge at the water inlet to the pipe inlet 33. The coolant from the external water channel flows into the 6 rotor internal water channels 12 through the pipe inlet 33.

[0023] In this embodiment, waterproofing is applied to the bearing 20 to ensure the seal at the connection point and to prevent any impact on motor operation. The waterproofing device includes a first waterproof cover plate 26, a second waterproof cover plate 28, a first waterproof sealing ring 27, a second waterproof sealing ring 30, and a waterproof sleeve 29. The waterproof sleeve 29 covers the outside of the bearing 20, and the inside of the bearing 20 is provided with a waterproof coating. The second waterproof cover plate 28 is annular, with its inner diameter matching the outer diameter of the bearing inner ring 32 and its outer diameter matching the outer diameter of the bearing outer ring 31. The second waterproof cover plate 28 is fixed to the water inlet end of the bearing 20, forming a closed dead end with the bearing 20. The second waterproof cover plate 28 is connected to the first waterproof cover plate 26 via the first waterproof sealing ring 27. The first waterproof cover plate 26, the second waterproof cover plate 28, and the first waterproof sealing ring 27 serve as the waterproofing device for the water inlet end of the bearing 20. The bearing inner ring 32 is connected to the pipe inlet 33 of the inner water cooling device via the second waterproof sealing ring 30. In this embodiment, the inner and outer water channels are connected by a bearing 20. The inner water channel is connected to the inner ring 32 of the bearing, and the outer water channel is connected to the outer ring 31 of the bearing, allowing the inner and outer water channels to rotate relative to each other. At this point, the outer water channel of the motor is connected to the outer ring 31 of the bearing and remains stationary with the end cover 11, the base 24, and the base cylinder 10; the inner water channel 33 of the motor is connected to the inner ring 32 of the bearing and is located outside the rotating shaft 19, rotating synchronously with the rotor components.

[0024] Furthermore, the cross-section of the internal water channel 12 of the rotor is fan-shaped. Figure 4 This is a cross-sectional view of the middle section of the rotor internal water channel 12, which is fixed between the rotor aluminum block 14 and the rotating shaft 19. A baffle 18 is installed inside the rotor internal water channel 12 to form a fixed flow path, ensuring that the coolant flows along the preset flow path 25 from the inlet 21 to the outlet 13 of the rotor internal water channel 12. The baffle 18 lengthens the coolant flow path inside the water channel, increasing the coolant flow distance and thus enhancing the cooling effect.

[0025] The flow path of the cooling medium is thus established. It flows in through the inlet 21, passes through the rotor internal water channel 12, flows through the preset flow channel 25 across the entire motor, and finally flows out from the outlet 13. This achieves the heat dissipation target for components with weak convection conditions, such as the rotor internal 17 and permanent magnet 23, thereby improving the electromagnetic performance and operational reliability of the motor and increasing its efficiency.

Claims

1. A water-cooling system for the rotor of a low-speed, high-torque permanent magnet synchronous motor, the permanent magnet synchronous motor comprising a rotor and a stator, characterized in that, The rotor's internal water cooling system includes an internal water cooling device, bearings, and a waterproofing device. The internal water cooling device is fixed to the inner wall of the rotor and rotates at the same speed as the rotor. The inner ring of the bearing is connected to the inlet end of the internal water cooling device, and the outer ring of the bearing is connected to the outlet end of the outer water channel. Coolant flows from the outer water channel along the gap in the middle of the inner ring of the bearing to the internal water cooling device. The connection between the water channels at both ends of the bearing is sealed off by the waterproofing device. The internal water cooling device includes multiple rotor internal water channels, with adjacent rotor internal water channels spaced evenly and distributed uniformly along the circumference of the shaft. Baffles are installed inside the rotor internal water channels to allow the coolant to flow along a pre-defined channel from the inlet to the outlet of the rotor internal water channel. The waterproofing device includes... The bearing includes a first waterproof cover plate, a second waterproof cover plate, a first waterproof sealing ring, a second waterproof sealing ring, and a waterproof sleeve. The waterproof sleeve covers the outside of the bearing, and the inside of the bearing is provided with a waterproof coating. The second waterproof cover plate is annular, with its inner diameter matching the outer diameter of the bearing's inner ring and its outer diameter matching the outer diameter of the bearing's outer ring. The first waterproof cover plate is fixed to the water inlet end of the bearing, and the second waterproof cover plate and the bearing together form a closed dead end. The second waterproof cover plate and the first waterproof cover plate are connected by the first waterproof sealing ring. The first waterproof cover plate, the second waterproof cover plate, and the first waterproof sealing ring serve as a waterproof device for the water inlet end of the bearing. The inner ring of the bearing is connected to the water inlet side of the inner water channel cooling device by the second waterproof sealing ring.

2. The internal water cooling system for the rotor of a low-speed, high-torque permanent magnet synchronous motor according to claim 1, characterized in that, The water channel inside the rotor has a fan-shaped cross-section and is fixed between the rotor aluminum block and the shaft.

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