Permanent magnet motor with hybrid cooling system

Abstract

The utility model relates to a kind of permanent magnet motor with mixed cooling system, permanent magnet motor includes the machine base of cylindrical, it defines the internal chamber for accommodating stator and rotor, rotor is installed on rotor shaft and forms air gap between stator;The outer peripheral surface of machine base is equipped with heat dissipation structure and apron, apron sealing connection is connected to the outer peripheral surface of machine base and covers heat dissipation structure, to limit outside external ventilation passage in the outer side of machine base, wherein external ventilation passage is in fluid communication with internal chamber;The inside of machine base is equipped with cooling jacket, for the liquid cooling of machine base and stator;And rotor includes multiple axial through holes passing through rotor core;Wherein permanent magnet motor is also equipped with airflow driving device, for guiding the air in internal chamber along external ventilation passage, multiple axial through holes and air gap circulation flow, to realize mixed cooling with cooling jacket cooperation.

Description

Technical Field

[0001] This utility model relates to the field of motor heat dissipation technology, and in particular to a permanent magnet motor with a hybrid cooling system. Background Technology

[0002] Permanent magnet motors are widely used in various industrial applications due to their high efficiency and compact structure. However, the performance and reliability of these motors are significantly affected by temperature rise, especially the temperature rise of the permanent magnets. When the temperature of the permanent magnets exceeds a certain limit, partial demagnetization may occur, leading to a decrease in motor efficiency. Furthermore, excessively high overall motor temperature rise can significantly shorten the service life of the insulation system.

[0003] To control motor temperature rise, various cooling structures have been proposed. Traditional cooling structures typically involve installing a water jacket inside the motor frame to cool the stator and frame. While this structure can reduce temperature to some extent, its heat dissipation capacity is limited, especially for high-power-density motors, where the cooling effect is not ideal. Another common structure involves installing a water jacket inside the frame and then mounting an external cooling unit on top of the frame to further enhance heat dissipation. However, this approach requires significant installation space, and the cooling unit is bulky, hindering compact equipment design.

[0004] Therefore, this utility model aims to improve the existing technology in one or more ways. Utility Model Content

[0005] In view of the shortcomings of the existing technology, this utility model proposes a permanent magnet motor with an improved hybrid cooling system, which can achieve higher heat transfer efficiency and better cooling effect, reduce the risk of demagnetization of permanent magnets, and thus extend the service life of permanent magnet motor.

[0006] Therefore, this utility model provides a permanent magnet motor with a hybrid cooling system. The permanent magnet motor includes a cylindrical base that defines an internal chamber for accommodating the stator and rotor. The rotor is mounted on a rotor shaft and forms an air gap with the stator. The outer circumferential surface of the base is provided with a heat dissipation structure and a cover plate. The cover plate is sealed to the outer circumferential surface of the base and covers the heat dissipation structure, thereby defining an external ventilation channel on the outside of the base, wherein the external ventilation channel is in fluid communication with the internal chamber. The interior of the base is provided with a cooling water jacket for liquid cooling of the base and the stator. The rotor includes multiple axial through holes penetrating the rotor core. The permanent magnet motor is also provided with an airflow drive device for guiding the air in the internal chamber to circulate along the external ventilation channel, the multiple axial through holes, and the air gap to achieve hybrid cooling in conjunction with the cooling water jacket.

[0007] In the aforementioned permanent magnet motor, the cooling water jacket inside the frame not only cools the frame and the adjacent stator, but also cools the heat dissipation structure located on the outside of the frame. Furthermore, the cover plate covering the heat dissipation structure forms a ventilation channel that is fluidly connected to the internal chamber of the permanent magnet motor. Combined with the rotor axial through-holes and air gap circulation, this achieves air cooling, further helping to remove heat from the rotor and the area surrounding the stator.

[0008] According to a preferred embodiment of the present invention, the heat dissipation structure forms multiple circumferentially spaced heat dissipation zones on the outer peripheral surface of the base, each heat dissipation zone including multiple heat dissipation components arranged side by side. The heat dissipation components are fixedly connected (e.g., by screws) to the outer peripheral surface of the base. Each heat dissipation component includes a base plate and multiple heat dissipation fins, wherein the base plate has an inner surface and an outer surface, and the multiple heat dissipation fins are located on the outer surface and extend parallel to the entire axial length of the base; the base plate has an arc-shaped cross-section adapted to the outer peripheral surface of the base, such that the inner surface of the base is in close contact with the outer peripheral surface of the base; and the axial length of the base plate is less than the axial length of the cover plate. Preferably, each heat dissipation zone is equipped with a cover plate, and the size and shape of the cover plate are selected to cover the corresponding heat dissipation zone. For example, the axial length of the cover plate is preferably equal to the axial length of the base.

[0009] The heat dissipation mechanism adopts the form of heat dissipation fins, which increases the overall heat dissipation area. The inner surface of the substrate is closely attached to the outer peripheral surface of the base, ensuring that heat can be effectively transferred from the base to the heat dissipation components, reducing thermal resistance and further improving the heat dissipation effect.

[0010] In one embodiment of this invention, the heat dissipation structure includes a first heat dissipation area and a second heat dissipation area arranged opposite each other along the diameter direction of the base, wherein the first heat dissipation area and the second heat dissipation area contain the same or different numbers of the heat dissipation components. This configuration of the heat dissipation areas allows for the uniform distribution of heat on both sides of the base, preventing localized overheating and improving the overall thermal management balance. It should be understood that, depending on the external structure of the base, the heat dissipation fins can be uniformly distributed or non-uniformly distributed along the outer circumference of the base.

[0011] In a preferred embodiment of this invention, the total coverage angle of the multiple heat dissipation zones distributed along the outer circumference of the base is 120° to 160°, and the heat dissipation components are made of aluminum alloy. In practical implementation, the total heat dissipation area of ​​the heat dissipation zones can be calculated by calculating the heat that the permanent magnet motor needs to dissipate. Selecting the total coverage angle of the multiple heat dissipation zones to be 120° to 160° will not result in excessive wind resistance and insufficient airflow, thus affecting heat dissipation.

[0012] According to a preferred embodiment of this utility model, the cross-section of the heat dissipation fins is a wedge shape that gradually tapers outward from the outer surface of the substrate, with a maximum width of 3mm to 8mm and a minimum width of 2mm to 3mm; the spacing between two adjacent heat dissipation fins on the outer surface is 3mm to 5mm; the radial distance from the inner surface of the substrate to the end of the heat dissipation fin is 22mm to 40mm. Maintaining a 3mm to 5mm spacing between adjacent heat dissipation fins on the outer surface ensures that air can flow evenly across each fin, avoiding local stagnation or heat dissipation dead zones, and improving the uniformity of air cooling. The radial distance from the inner surface of the substrate to the end of the heat dissipation fin is 22mm to 40mm, ensuring that the heat dissipation area is sufficient to meet the heat conduction requirements while avoiding excessively long fins that would increase air resistance or occupy too much structural space, thus achieving a balance between heat dissipation efficiency and structural compactness. However, it should be understood that the above-mentioned dimensional data are merely exemplary, and other suitable dimensions can be selected according to actual needs, which are also covered within the scope of this application.

[0013] In one embodiment of this invention, the base has a first end and an opposing second end, wherein the first end is provided with a first vent, and the second end is provided with a second vent. An external ventilation channel is in fluid communication with the internal chamber via the first and second vents. This configuration of the vents allows cooler air from the external ventilation channel to travel from one axial side of the internal chamber of the permanent magnet motor through multiple axial through-holes and air gaps to the other axial side of the internal chamber. This helps to evenly remove heat around the stator and rotor, reduce localized hot spots, and improve the uniformity of the motor's temperature distribution.

[0014] In a preferred embodiment of this invention, the airflow drive device is a radial fan disposed at the drive end of the rotor shaft, used to drive hot air from the plurality of axial through holes and the air gap into the external ventilation channel via the second vent. As the radial fan rotates with the rotor shaft, it can efficiently extract hot air from the axial through holes of the rotor and the air gap between the rotor and stator and guide it into the external ventilation channel, forming forced air circulation and improving the air cooling efficiency inside the machine base.

[0015] In a preferred embodiment of this invention, multiple axial through holes are evenly spaced along the circumference of the rotor core; and the cross-section of each axial through hole is a fan-shaped annulus. The fan-shaped annulus design balances the through hole area and structural strength, resulting in lower airflow resistance while maintaining the mechanical strength of the rotor core, thus achieving a balance between heat dissipation efficiency and structural stability.

[0016] Advantageously, the number and size of the multiple axial through holes are selected such that the airflow through the multiple axial through holes accounts for 75% to 85%, preferably 80%, of the total airflow through the multiple axial through holes and the air gap. By rationally selecting the number and size of the multiple axial through holes, most of the air flows through them, which can efficiently remove heat from the rotor's interior, optimize airflow distribution, equalize temperature, and improve the motor's heat dissipation efficiency and reliability.

[0017] The cooling water jacket is in fluid communication with the external liquid circulation system through the liquid inlet and liquid outlet ports provided on the base, forming an external circulation loop for the cooling liquid. Attached Figure Description

[0018] Exemplary embodiments of the present invention are described with reference to the accompanying drawings, wherein:

[0019] Figure 1 A perspective view of a permanent magnet motor according to an embodiment of the present invention is shown;

[0020] Figure 2 for Figure 1 The longitudinal sectional view of the permanent magnet motor shown;

[0021] Figure 3 for Figure 1 A cross-sectional view of the permanent magnet motor shown.

[0022] Figure 4 A perspective view of a base with a heat dissipation structure and a cover plate according to an embodiment of the present invention;

[0023] Figure 5 for Figure 3 An exploded view of the machine base shown;

[0024] Figure 6 A perspective view of an embodiment of a heat dissipation component with heat dissipation fins according to the present invention; and

[0025] Figure 7 for Figure 6 The end view of the heat dissipation component shown.

[0026] The accompanying drawings are merely illustrative and not necessarily drawn to scale. Furthermore, they only show those parts necessary to illustrate the present invention; other parts are omitted or merely mentioned. That is, the present invention may include other parts besides those shown in the drawings. Detailed Implementation

[0027] The technical solution of this utility model will be described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth to enable those skilled in the art to gain a more comprehensive understanding of this utility model. However, it will be apparent to those skilled in the art that implementations of this utility model may not include some of these specific details. Furthermore, it should be understood that this utility model is not limited to the specific embodiments described. Rather, this utility model can be conceived to be implemented with any combination of the following features and elements, regardless of whether they relate to different embodiments.

[0028] The terms "first" and "second" are used below to describe the elements of this application. These terms are used only to distinguish the individual elements and not to limit the nature, order, or number of these elements. The terms "comprising" and "having" are used to indicate an open-ended inclusion and mean that there may be additional elements / components besides those listed.

[0029] In order to overcome the shortcomings of the prior art mentioned in the background section, this utility model proposes a permanent magnet motor with an improved hybrid cooling system. Figure 1 A perspective view of a permanent magnet motor according to an embodiment of the present invention is shown. Figure 2 and Figure 3 They are respectively Figure 1 The longitudinal and transverse sectional views of the permanent magnet motor shown illustrate its internal structure.

[0030] As can be seen from the figure, the permanent magnet motor 100 includes a cylindrical base 1, which defines an internal chamber 10 for accommodating the stator 2 and the rotor 3. The rotor 3 is mounted on the rotor shaft 4 and forms an air gap S between it and the stator 2. The stator 2 can be press-fitted to the inner circumferential surface of the base, for example, by interference fit.

[0031] Advantageously, the outer peripheral surface 1a of the base 1 is provided with a heat dissipation structure 5 and a cover plate 6. The cover plate 6 is sealed to the outer peripheral surface of the base 1 and covers the heat dissipation structure 5, thereby defining an external ventilation channel L1 on the outside of the base. The interior of the base 1 is provided with a cooling water jacket 13 for liquid cooling of the base 1 and the stator 2, through a liquid inlet port 13a and a liquid outlet port 13b provided on the base 1 (see...). Figure 4 It is fluidly connected to an external liquid circulation system (not shown), forming an external circulation loop for the cooling liquid, thereby improving the temperature control performance of the frame and stator and ensuring long-term reliable operation of the permanent magnet motor under high loads. Furthermore, as... Figure 3 As shown, the rotor 3 includes multiple axial through holes 31 that penetrate the rotor core.

[0032] See especially Figure 2Along the axial direction of the permanent magnet motor, the base 1 has a first end 11 and a corresponding second end 12. The first end 11 is provided with a first vent 11a, and the second end 12 is provided with a second vent 12a. The external ventilation channel L1 is in fluid communication with the internal chamber 10 through the first vent 11a and the second vent 12a, forming a closed-loop airflow path that runs through both ends of the base.

[0033] In this embodiment, the permanent magnet motor also includes an airflow drive device 7, such as a radial fan located at the drive end 41 of the rotor shaft 4 (i.e., the end near the second vent 12a), for driving air circulation. The radial fan directs hot air (such as from the multiple axial through holes 31 and the air gap S) into the airflow. Figure 2 (As shown by the red arrow in the image) the hot air flows into the external ventilation channel L1 via the second vent 12a. In the external ventilation channel L1, the hot air is cooled by the heat dissipation structure 5 and becomes cooler air at a lower temperature (as shown by the red arrow). Figure 2 (As shown by the blue arrow in the image), the air then enters the region of the internal chamber 10 near the first end 11 via the first vent 11a. Then, under the continuous action of the radial fan, the cool air is drawn through the air gap S between the stator and rotor and the axial through-hole 31 in the rotor 3, flowing towards the region of the internal chamber 10 near the drive end of the rotor shaft, thus achieving a closed-loop circulation of air inside the motor. This circulation achieves the synergistic effect of air cooling and liquid cooling, significantly improving the overall heat dissipation capacity of the permanent magnet motor.

[0034] During air circulation, since the cooling water jacket 13 is located inside the base 1, it can not only liquid cool the base 1 and the stator 2, but also cool the heat dissipation structure 5 fixed on the outer circumference of the base, so that the hot air passing through the external ventilation channel L1 can be cooled more efficiently when it flows through the heat dissipation structure 5.

[0035] See you again Figure 3 In a preferred embodiment, the rotor 3 has multiple axial through holes 31 evenly spaced along the circumference of the rotor core, and the cross-section of each axial through hole 31 is preferably fan-shaped. This structure can form a uniform channel area in the circumferential direction, resulting in less pressure loss when air or other cooling media flow along the circumference of the stator or rotor. Furthermore, the fan-shaped through holes 31 have a streamlined profile, which helps reduce the generation of airflow turbulence and eddies, thereby reducing wind noise. Their arc-shaped edges also make the stress distribution more uniform, avoiding stress concentration at sharp corners or right angles. Compared with rectangular or circular holes, this shape has better vibration resistance and is more suitable for high-speed rotating motors.

[0036] In the illustrated embodiment, the rotor 3 is provided with eight axial through holes 31. However, it should be understood that other numbers and shapes of axial through holes can also be provided according to cooling requirements, as long as the number and size of the axial through holes 31 enable the airflow through the multiple axial through holes 31 to account for 75% to 85%, preferably 80%, of the total airflow through the multiple axial through holes 31 and the air gap S. This is because it enables efficient removal of heat from the rotor's interior, equalizes temperature distribution, and improves the air-cooling effect.

[0037] See Figure 3 , Figure 4 and Figure 5 In a preferred embodiment, the heat dissipation structure 5 forms two circumferentially spaced heat dissipation areas on the outer peripheral surface of the base 1, namely a first heat dissipation area 5a and a second heat dissipation area 5b arranged opposite each other along the diameter direction of the base 1. Each heat dissipation area includes four heat dissipation components 50 arranged side by side, which can be fixedly connected to the outer peripheral surface of the base 1, for example, by bolts.

[0038] Although two heat dissipation zones are shown in the figure, one or more heat dissipation zones may be used depending on the chassis structure and application scenario. In this embodiment, the first heat dissipation zone 5a and the second heat dissipation zone 5b contain the same number of heat dissipation components 50, but they can also be configured with different numbers of components according to the heat dissipation requirements of different areas. For example, the total coverage angle of multiple heat dissipation zones distributed along the outer peripheral surface of the chassis 1 can be 120° to 160°. Figure 3 The total coverage angle of the heat dissipation area shown is, for example, approximately 150°, which ensures sufficient heat dissipation area while avoiding obstruction of airflow.

[0039] like Figure 4 As shown, each heat dissipation area is equipped with a cover plate 6. The shape and size of the cover plate 6 are suitable for covering the corresponding heat dissipation area to enhance the air cooling effect. In a preferred embodiment, the cover plate 6 is arc-shaped, and its axial length is basically the same as the axial length of the base 1 and greater than the axial length of the heat dissipation structure 5, thereby ensuring that the cover plate 6 completely covers the heat dissipation area and forms an external ventilation channel L1, while improving airflow efficiency.

[0040] See Figure 6 and Figure 7 Each heat dissipation component 50 includes a substrate 51 and a plurality of heat dissipation fins 52. The substrate 51 has an inner surface 51a and an outer surface 51b. The heat dissipation fins 52 are disposed on the outer surface 51b and extend parallel to the entire axial length of the substrate. The substrate 51 has an arcuate cross-section that is adapted to the outer peripheral surface of the base 1, so that the inner surface 51a is in close contact with the base 1.

[0041] In a preferred embodiment, the heat dissipation component 50 is made of aluminum alloy. Compared to cast iron or steel commonly used in the prior art, aluminum alloy has approximately five times the thermal conductivity, thus significantly improving heat dissipation efficiency.

[0042] See especially Figure 7 In a specific embodiment, the cross-section of each heat dissipation fin 52 is a wedge shape that tapers outward from the outer surface of the substrate 51, with a maximum width of 3mm to 8mm and a minimum width of 2mm to 3mm. The spacing between two adjacent heat dissipation fins 52 at the outer surface is 3mm to 5mm, and the radial distance from the inner surface 51a of the substrate 51 to the end 52a of the heat dissipation fin 52 is 22mm to 40mm. This design can increase the contact area between air and fins, improve airflow velocity, optimize air cooling, and maintain a compact structure.

[0043] In practical applications, the number of heat dissipation components 50, the coverage angle of the heat dissipation zone, the size of the heat dissipation fins 52 and the number of axial through holes 31 can be appropriately adjusted according to the power and heat requirements of the permanent magnet motor to meet the thermal management requirements of different models or power levels of motors, thereby ensuring that the motor temperature rise is balanced, the reliability is high and the lifespan is long under high load conditions.

[0044] In summary, the hybrid cooling system described in this embodiment achieves an organic combination of liquid cooling and air cooling through the liquid cooling effect of the internal cooling water jacket 13 and the air cooling effect of the external ventilation channel L1 in conjunction with the axial through hole 31 and the radial fan 7. This significantly improves the heat dissipation efficiency of the permanent magnet motor, optimizes the temperature distribution, and enhances the reliability of the motor during long-term operation. It is particularly suitable for permanent magnet motors operating under high power density and continuous operation conditions. Furthermore, the permanent magnet motor using this hybrid cooling system according to this utility model can achieve the following significant technical effects:

[0045] (1) The temperature of the permanent magnet is significantly reduced by about 20K, which effectively prevents the permanent magnet from demagnetizing and improves the overall performance of the motor;

[0046] (2) The overall temperature rise of the motor is reduced, which extends the service life of the insulation system;

[0047] (3) The temperature gradient of the stator core is reduced, which can reduce the thermal expansion stress caused by the shrinkage of the stator and the frame.

[0048] Therefore, the permanent magnet motor product according to this utility model has a wider range of applications and better market adaptability.

[0049] The above illustrative embodiments have clearly and completely described the present invention. Those skilled in the art should understand that various other embodiments can be conceived through modifications to the disclosed technical solutions without departing from the spirit and scope of the present invention. These embodiments should be understood to fall within the scope of the present invention as defined by the claims and any equivalent technical solutions.

Claims

1. A permanent magnet motor with a hybrid cooling system, the permanent magnet motor (100) comprising a cylindrical base (1) defining an internal cavity (10) for accommodating a stator (2) and a rotor (3), the rotor (3) being mounted on a rotor shaft (4) and forming an air gap (S) between the rotor (2) and the stator (2); Its features are, The outer peripheral surface (1a) of the base (1) is provided with a heat dissipation structure (5) and a cover plate (6). The cover plate is sealed to the outer peripheral surface of the base and covers the heat dissipation structure, thereby defining an external ventilation channel (L1) on the outside of the base, wherein the external ventilation channel is in fluid communication with the internal chamber (10). The machine base (1) is equipped with a cooling water jacket (13) for liquid cooling of the machine base and the stator; and The rotor (3) includes multiple axial through holes (31) penetrating the rotor core; The permanent magnet motor is further provided with an airflow drive device (7) for guiding the air in the internal chamber to circulate along the external ventilation channel (L1), the plurality of axial through holes (31) and the air gap (S) to cooperate with the cooling water jacket (13) to achieve mixed cooling.

2. The permanent magnet motor according to claim 1, characterized in that, The heat dissipation structure (5) forms multiple heat dissipation zones spaced apart along the circumference on the outer peripheral surface of the base (1). Each heat dissipation zone includes multiple heat dissipation components (50) arranged side by side. The heat dissipation components are fixedly connected to the outer peripheral surface of the base (1). Each of the heat dissipation components includes a substrate (51) and a plurality of heat dissipation fins (52), wherein the substrate (51) has an inner surface (51a) and an outer surface (51b), and the plurality of heat dissipation fins are located on the outer surface and extend parallel to the entire axial length of the substrate. The substrate (51) has an arc-shaped cross-section that is adapted to the outer peripheral surface of the base (1), so that the inner surface of the substrate is in close contact with the outer peripheral surface of the base. Furthermore, the axial length of the substrate is less than the axial length of the cover plate (6).

3. The permanent magnet motor according to claim 2, characterized in that, The heat dissipation structure (5) includes a first heat dissipation area (5a) and a second heat dissipation area (5b) arranged opposite to each other along the diameter direction of the base (1), wherein the first heat dissipation area (5a) and the second heat dissipation area (5b) contain the same number or different numbers of the heat dissipation components (50).

4. The permanent magnet motor according to claim 2, characterized in that, The total coverage angle of the plurality of heat dissipation zones distributed along the outer peripheral surface of the base (1) is 120° to 160°, and the heat dissipation component is made of aluminum alloy material; Each of the heat dissipation zones is provided with a cover plate (6), and the shape and size of the cover plate are selected to cover the corresponding heat dissipation zone.

5. The permanent magnet motor according to claim 2, characterized in that, The heat dissipation fins (52) have a cross-section that tapers outward from the outer surface of the substrate (51) and have a maximum width of 3 mm to 8 mm and a minimum width of 2 mm to 3 mm. The distance between two adjacent heat dissipation fins (52) on the outer surface is 3 mm to 5 mm; The radial distance from the inner surface of the substrate to the end of the heat dissipation fin (52) is 22 mm to 40 mm.

6. The permanent magnet motor according to any one of claims 1 to 5, characterized in that, The base (1) has a first end (11) and an opposite second end (12), wherein the first end (11) is provided with a first vent (11a) and the second end (12) is provided with a second vent (12a), and the external ventilation channel (L1) is in fluid communication with the internal chamber (10) via the first vent (11a) and the second vent (12a).

7. The permanent magnet motor according to claim 6, characterized in that, The airflow drive device (7) is a radial fan installed at the drive end of the rotor shaft (4) for driving hot air from the plurality of axial through holes (31) and the air gap into the external ventilation channel (L1) via the second vent (12a).

8. The permanent magnet motor according to any one of claims 1 to 5, characterized in that, The plurality of axial through holes (31) are evenly spaced along the circumference of the rotor core; and Each of the axial through holes (31) has a fan-shaped cross-section.

9. The permanent magnet motor according to claim 8, characterized in that, The number and size of the plurality of axial through holes (31) are selected such that the air flow through the plurality of axial through holes (31) accounts for 75% to 85% of the total air flow through the plurality of axial through holes (31) and the air gap (S).

10. The permanent magnet motor according to any one of claims 1 to 5, characterized in that, The cooling water jacket (13) is in fluid communication with the external liquid circulation system through the liquid inlet port (13a) and liquid outlet port (13b) provided on the base (1), forming an external circulation loop of cooling liquid.

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