Permanent magnet synchronous traction motor

Abstract

The application provides a permanent magnet synchronous traction motor. The permanent magnet synchronous traction motor comprises a machine shell, a motor rotor shaft, a bearing outer cover and a cooling device. The cooling device comprises heat dissipation fins mounted on the outer surface of the bearing outer cover and semiconductor cooling fins mounted in the bearing outer cover and the machine shell sidewall. One end of the semiconductor cooling fins is a cold end for absorbing heat, and the other end is a hot end for releasing heat. The hot end is in contact with the heat dissipation fins, and the cold end is close to the bearing. The application adopts the semiconductor cooling fins to guide the heat of the bearing and accessories to the external heat dissipation fins, and then dissipates the heat of the fins into the external environment through air cooling, effectively ensures that the bearing temperature rise of the high-speed permanent magnet motor is within a reasonable range, ensures the heat dissipation efficiency, reduces the winding and bearing temperature rise, and improves the long-term operation reliability of the permanent magnet motor.

Description

Technical Field

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

[0002] Currently, traction motors are developing towards higher speeds and lighter weights. With the increase in power density, the heat dissipation problem caused by motor miniaturization is becoming increasingly prominent. Under continuous, complex, and harsh operating conditions, the stator windings and bearings generate severe heat, which will seriously affect the service life of the traction motor in the long run.

[0003] Currently, there are three common cooling methods for traction motors: self-ventilated cooling, forced air cooling, and liquid cooling. Among them, liquid-cooled motors have the highest cooling efficiency, but their cooling water channels are usually laid on the frame and are only used to cool the stator windings, failing to effectively cool the bearings. There are also a few cases where the cooling water channels simultaneously cool the stator and bearings, but this method results in a more complex sealing structure connecting the frame water channels to the end cover bearing position, posing a risk of failure and leakage during long-term operation of the traction motor.

[0004] With the miniaturization, lightweighting and high-speed development of permanent magnet motors, permanent magnet motors using single cooling cannot simultaneously cool the stator windings and bearings. Especially for high-speed motors, due to the high bearing speed, the heat radiation generated by the bearing's own mechanical friction is also large, resulting in high bearing operating temperature, grease loss, and reduced bearing test life, which will affect the safe operation of trains. Summary of the Invention

[0005] The purpose of this invention is to provide a permanent magnet synchronous traction motor that can ensure heat dissipation efficiency, reduce the temperature rise of windings and bearings, and improve the long-term operational reliability of the permanent magnet motor.

[0006] The technical solution of the present invention is: a permanent magnet synchronous traction motor, comprising a housing, a motor rotor shaft mounted in the housing via bearings, a bearing cover disposed at the end of the housing for fixing the bearing, and a cooling device disposed on the bearing cover for dissipating heat from the bearing. The cooling device includes heat dissipation fins mounted on the outer surface of the bearing cover and a semiconductor cooling plate. The semiconductor cooling plate is simultaneously mounted in the bearing cover and the side wall of the housing. One end of the semiconductor cooling plate is a cold end that absorbs heat, and the other end is a hot end that releases heat. The hot end is in contact with the heat dissipation fins, and the cold end is disposed close to the bearing.

[0007] In the above solution, the heat from the bearings and accessories is transferred to the external heat dissipation fins, and then the heat from the fins is dissipated into the external environment through air cooling. This effectively ensures that the bearing temperature rise of the high-speed permanent magnet motor is within a reasonable range, guarantees heat dissipation efficiency, reduces the temperature rise of the windings and bearings, and improves the long-term operational reliability of the permanent magnet motor.

[0008] Preferably, the motor rotor shaft has bearings and bearing covers at both ends, and each bearing cover at each end has a cooling device. The cooling devices at both ends are symmetrically arranged.

[0009] Preferably, the hot end is provided with a lead wire that extends out of the housing.

[0010] Preferably, the housing includes a cylindrical base with two through ends and end caps installed at both ends of the base, the bearing outer cover is installed on the end caps, and the semiconductor cooling plate is disposed in the end caps.

[0011] Preferably, the base is provided with an annular cooling channel that allows cooling liquid to pass through, and the cooling channel extends along the axial direction of the base.

[0012] Preferably, a rotor is mounted on the motor rotor shaft, and a stator core is mounted on the outside of the rotor, with stator windings provided on the stator core.

[0013] Preferably, a pressure rubber pad is provided between the heat dissipation fins and the bearing outer cover to adjust the pressure between the heat dissipation fins and the semiconductor cooling plate, so that heat conduction occurs between the root of the heat dissipation fins and the semiconductor cooling plate.

[0014] Preferably, an axial fan is provided on the outer surface of the heat dissipation fins.

[0015] In one specific embodiment, the heat dissipation fins are rectangular, and the rectangular heat dissipation fins are disposed on both sides of the bearing outer cover, with each heat dissipation fin corresponding to a semiconductor cooling plate.

[0016] In another specific embodiment, the heat dissipation fins are annular, and multiple semiconductor cooling plates are arranged along the annular heat dissipation fins.

[0017] Compared with related technologies, the beneficial effects of the present invention are as follows: I. The composite cooling structure adopts liquid cooling for the stator windings, semiconductor cooling plates and heat sinks for the bearings, which can effectively ensure that the bearing temperature rise of the high-speed permanent magnet motor is controlled within a reasonable range, and improve the long-term operational reliability of key components such as the traction motor insulation system and bearings.

[0018] Second, the present invention installs an axial fan on the heat dissipation fins to further ensure heat dissipation efficiency, reduce the temperature rise of the windings and bearings, and improve the long-term operational reliability of the permanent magnet motor. Attached Figure Description

[0019] Figure 1 A schematic diagram of the internal structure of the permanent magnet synchronous traction motor according to Embodiment 1 of the present invention; Figure 2 for Figure 1A schematic diagram of the side view structure in the middle; Figure 3 for Figure 1 Enlarged view of point I in the middle; Figure 4 A schematic diagram of the internal structure of the permanent magnet synchronous traction motor according to Embodiment 2 of the present invention; Figure 5 for Figure 4 A schematic diagram of the side view structure; Figure 6 This is a schematic diagram of a semiconductor cooling pad structure consisting of a multi-stage cooling stack. Figure 7 A schematic diagram of the internal structure of the permanent magnet synchronous traction motor according to Embodiment 4 of the present invention; Figure 8 for Figure 7 A side view structural diagram.

[0020] In the attached diagram: 1. Housing; 11. Base; 111. Cooling channel; 12. End cover; 13. Bearing cover; 2. Motor rotor shaft; 3. Bearing; 4. Cooling device; 41. Semiconductor cooling fin; 411. Cold end; 412. Hot end; 42. Heat dissipation fins; 43. Lead wire; 5. Rotor; 6. Stator core; 7. Stator winding; 8. Rubber pad; 9. Axial fan. Detailed Implementation

[0021] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other. For ease of description, the terms "upper," "lower," "left," and "right" used below only indicate that they correspond to the upper, lower, left, and right directions in the accompanying drawings and do not limit the structure.

[0022] Example 1 like Figure 1 As shown, the permanent magnet synchronous traction motor provided in this embodiment includes a housing 1, a motor rotor shaft 2, a bearing 3, a cooling device 4, a rotor 5, a stator core 6, a stator winding 7, and a rubber pad 8.

[0023] The housing 1 includes a cylindrical base 11 extending through both ends, end caps 12 mounted on both ends of the base 11, and a bearing cover 13 located at the end of the housing 1 for fixing the bearing 3. The base 11 contains an annular cooling channel 111 through which cooling liquid flows, extending axially along the base 11. The cooling channel 111 has an outlet and an inlet; the inlet is connected to a water source, and the outlet discharges hot water, forming a water-cooled circulation.

[0024] The motor rotor shaft 2 is installed inside the housing 1, and bearings 3 are respectively installed at both ends of the motor rotor shaft 2. The axial position of the bearings 3 is defined by end caps 12 and bearing outer caps 13. The outer ring of the bearing 3 is fitted into the end cap 12, and the inner ring of the bearing 3 is fitted onto the motor rotor shaft 2.

[0025] The cooling device 4 is mounted on the bearing outer cover 13 to dissipate heat from the bearing 3. The cooling device 4 includes heat dissipation fins 42 mounted on the outer surface of the bearing outer cover 13, and semiconductor cooling plates 41 mounted in the bearing outer cover 13 and end cap 12. The semiconductor cooling plates 41 are in contact with the heat dissipation fins 42. The cooling devices 4 are symmetrically arranged at both ends of the motor rotor shaft 2. The heat dissipation fins 42 are mounted on the bearing outer cover 13 using rubber pads 8 and bolts (not labeled).

[0026] like Figure 1 , Figure 3 As shown, the semiconductor cooling plate 41 utilizes the Peltier effect for cooling. Its core structure is composed of N-type and P-type semiconductor materials. When direct current passes through these semiconductor materials, heat transfer occurs at both ends of the thermocouple pair: one end absorbs heat (cold end 411), and the other end releases heat (hot end 412). The hot end 412 is in contact with the heat dissipation fins 42, and a lead wire 43 extends out of the housing 1 from the hot end 412, through which a 24V or 12V low-voltage DC power supply is connected. The cold end 411 is located near the bearing 3. Specifically, when current passes through the thermocouple pair formed by the N-type and P-type semiconductor materials, the junction where the current flows from the N-type element to the P-type element absorbs heat, becoming the cold end 411; while the junction where the current flows from the P-type element to the N-type element releases heat, becoming the hot end 412. By changing the direction of the current, the hot and cold ends can be switched. When the motor operates under harsh conditions, the bearing 3 may overheat. In such cases, the semiconductor cooling plate 41 can be energized to dissipate heat from the bearing 3.

[0027] The semiconductor cooling plate 41 conducts heat from the bearing 3 and its accessories to the heat dissipation fins 42. For example... Figure 2 As shown, when the rail vehicle is running, the airflow carries away heat through the heat dissipation fins 42. The heat dissipation fins 42 are made of aluminum alloy with high thermal conductivity. An elastic rubber pad 8 is used to adjust the pressure between the heat dissipation fins 42 and the semiconductor cooling plate 41, ensuring effective heat conduction between the base of the heat dissipation fins 42 and the semiconductor cooling plate 41. The vertical direction of the heat dissipation fins 42 is consistent with the direction of the airflow.

[0028] To ensure that heat is dissipated from the vicinity of bearing 3, thermally conductive silicone grease may be filled between the mounting holes of the semiconductor cooling plate 41, the heat dissipation fins 42, and the end cap 12.

[0029] like Figure 1As shown, a rotor 5 is mounted on the rotor shaft 2 of the motor, and a stator core 6 is mounted on the outside of the rotor 5. A stator winding 7 is provided on the stator core 6.

[0030] like Figure 1 , Figure 2 As shown, in this embodiment, the heat dissipation fins 42 are rectangular and are disposed on opposite sides of the bearing outer cover 13. Each heat dissipation fin 42 is provided with a semiconductor cooling plate 41. The rectangular structure simplifies the processing of the heat dissipation fins 42 and is suitable for environments with general heat dissipation requirements.

[0031] Example 2 like Figure 4 , Figure 5 As shown, this embodiment repeats Embodiment 1, except that the heat dissipation fins 42 in this embodiment are annular, and multiple semiconductor cooling plates 41 are arranged along the annular heat dissipation fins 42. The cooling device 4 in this embodiment has a larger heat conduction and heat dissipation area, making it suitable for environments with higher heat dissipation requirements for the bearing 3.

[0032] Example 3 like Figure 6 As shown, in this embodiment, the semiconductor cooling sheet 41 has a multi-level structure that is stacked sequentially along the axis, and the temperature is gradually reduced through this stacking structure. Figure 6 In the middle, the hot surface of the previous stage is in close contact with the cold surface of the next stage, and the heat is transferred to the heat dissipation fins 42 step by step.

[0033] Example 4 like Figure 7 , Figure 8 As shown, due to the limited installation space of the traction motor on the bogie of the rail vehicle, the area around the heat dissipation fins 42 is obstructed by equipment. This results in a low airflow velocity at the heat dissipation fins 42, which cannot effectively dissipate heat from the bearing. To address this issue, an exhaust-type axial fan 9 is installed on the outer surface of the heat dissipation fins 42 to further enhance heat dissipation. The axial fan 9 can be powered by a 12V or 24V DC power supply. The motor of the axial fan 9 can be mounted on the heat dissipation fins 42 or the bearing cover 13.

[0034] In specific implementations of this invention, the contents not described in detail in this specification are existing technologies known to those skilled in the art.

[0035] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A permanent magnet synchronous traction motor, comprising a housing (1), a motor rotor shaft (2) mounted in the housing (1) via a bearing (3), and a bearing cover (13) disposed at the end of the housing (1) for fixing the bearing (3), characterized in that, It also includes a cooling device (4) provided on the bearing cover (13) for dissipating heat from the bearing (3). The cooling device (4) includes heat dissipation fins (42) and semiconductor cooling plates (41) installed on the outer surface of the bearing cover (13). The semiconductor cooling plates (41) are installed in both the bearing cover (13) and the side wall of the housing (1). One end of the semiconductor cooling plate (41) is a cold end (411) that absorbs heat, and the other end is a hot end (412) that releases heat. The hot end (412) is in contact with the heat dissipation fins (42), and the cold end (411) is located close to the bearing (3).

2. The permanent magnet synchronous traction motor according to claim 1, characterized in that, The motor rotor shaft (2) is provided with bearings (3) and bearing covers (13) at both ends, and a cooling device (4) is provided on the bearing cover (13) at each end.

3. The permanent magnet synchronous traction motor according to claim 1, characterized in that, The hot end (412) is provided with an outgoing lead (43) that extends out of the casing (1).

4. The permanent magnet synchronous traction motor according to claim 1, characterized in that, The housing (1) includes a cylindrical base (11) with both ends through it, and end caps (12) installed at both ends of the base (11). The bearing outer cover (13) is installed on the end cap (12), and the semiconductor cooling plate (41) is disposed in the end cap (12).

5. The permanent magnet synchronous traction motor according to claim 4, characterized in that, The base (11) is provided with an annular cooling channel (111) that allows cooling liquid to pass through, and the cooling channel (111) extends along the axial direction of the base (11).

6. The permanent magnet synchronous traction motor according to claim 1, characterized in that, The rotor shaft (2) of the motor is fitted with a rotor (5), and the rotor (5) is fitted with a stator core (6), and the stator core (6) is provided with a stator winding (7).

7. The permanent magnet synchronous traction motor according to claim 1, characterized in that, A pressure rubber pad (8) is provided between the heat dissipation fins (42) and the bearing cover (13) to adjust the pressure between the heat dissipation fins (42) and the semiconductor cooling plate (41), so that heat conduction occurs between the root of the heat dissipation fins (42) and the semiconductor cooling plate (41).

8. The permanent magnet synchronous traction motor according to claim 1, characterized in that, An axial fan (9) is provided on the outer surface of the heat dissipation fins (42).

9. The permanent magnet synchronous traction motor according to any one of claims 1-8, characterized in that, The heat dissipation fins (42) are rectangular, and the rectangular heat dissipation fins (42) are respectively disposed on both sides of the bearing outer cover (13). Each heat dissipation fin (42) is provided with a semiconductor cooling plate (41).

10. The permanent magnet synchronous traction motor according to any one of claims 1-8, characterized in that, The heat dissipation fins (42) are circular, and multiple semiconductor cooling plates (41) are arranged along the circular heat dissipation fins (42).

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