Motor structure with synergistic cooling of magnetic flux leakage driving and bionic flow guiding

Abstract

The application discloses a motor structure with synergistic cooling of magnetic flux leakage driving and bionic flow guiding, comprising a casing, a stator, a winding, an oil separation ring and a plurality of vibrating diaphragm cooling units; the casing is provided with an oil inlet and an oil outlet, the stator is arranged inside the casing, the winding is arranged on the stator, the oil separation ring is arranged in the adjacent area of the stator and the rotor, the plurality of vibrating diaphragm cooling units are arranged at the end of the stator or the adjacent area of the winding, each vibrating diaphragm cooling unit is arranged towards the winding and keeps a gap with the outer surface of the winding to form a local cooling oil action area; each vibrating diaphragm cooling unit comprises a diaphragm body, a coil assembly and a bionic flow guiding rib, the coil assembly induces magnetic flux leakage or is externally powered to excite the diaphragm to vibrate, and the bionic flow guiding rib guides the disturbed oil flow to promote liquid renewal. Through the synergistic effect of magnetic flux leakage driving and bionic flow guiding, the application realizes the remarkable improvement of the motor cooling performance and is suitable for high-power density immersed oil-cooled motors.

Description

Technical Field

[0001] This invention belongs to the field of motor thermal management technology, specifically relating to a motor structure that utilizes the leakage magnetic energy at the motor end to drive a vibrating diaphragm and combines a biomimetic flow guiding structure to enhance the flow and heat transfer of cooling oil, suitable for high power density immersed oil-cooled motors. Background Technology

[0002] With the increasing application of high power density and high torque density motors in new energy vehicles, aerospace electric propulsion, and high-end equipment, motor thermal management issues are becoming increasingly prominent. Existing motor cooling methods mainly include air cooling, indirect liquid cooling such as water jackets for the casing, direct oil cooling, and other enhanced heat dissipation methods. Among these, direct liquid cooling has become one of the important development directions for high power density motors because it can be closer to the heat-generating parts and improve the heat dissipation capacity per unit volume.

[0003] Among the various heat-generating components of a motor, the stator windings, especially the end windings, are often considered one of the hotspots. This is because the end windings have complex geometry, a significant three-dimensional leakage magnetic field, and weak heat conduction paths with the housing and other traditional cooling channels. Furthermore, the heat transfer conditions within the end space are uncertain, resulting in lower heat dissipation capacity in this region compared to the slot windings and parts of the core. Therefore, reducing the temperature rise of the end windings and improving local heat transfer are pressing technical challenges in motor thermal management. For end winding heat dissipation, existing technologies have proposed solutions such as end oil injection, impingement jet cooling, direct winding cooling, and immersion liquid cooling. These solutions can reduce the winding temperature to a certain extent, but there are still some shortcomings: on the one hand, the coolant is prone to low-speed zones, stagnant zones, or uneven local heat transfer in the complex space at the end; on the other hand, under immersion liquid cooling or direct oil cooling conditions, the near-wall liquid layer attached to the winding surface is prone to forming a relatively stable thermal boundary layer, thereby limiting the transfer of local heat to the mainstream coolant, making it difficult to further reduce the local hot spots at the end.

[0004] On the other hand, studies on ultrasonic-enhanced heat transfer have shown that high-frequency vibrations acting on liquids can enhance heat transfer through mechanisms such as acoustic flow, cavitation, and near-wall fluid disturbance. Among these, acoustic flow and cavitation are generally considered to be the two main enhancement mechanisms. In scenarios with liquid films, near-wall flow layers, or localized small cavities, high-frequency vibrations help weaken the thermal boundary layer, promote liquid renewal, and improve local convective heat transfer capacity. This mechanism provides a new technical approach for enhancing localized heat transfer under immersion liquid cooling conditions at the motor end.

[0005] However, most existing motor cooling technologies focus on improving the main flow path, increasing coolant flow, or optimizing the spray path. There is still a lack of compact and easily integrated solutions for enhancing heat transfer in the end winding region by utilizing local end structures to conduct high-frequency disturbances of the near-wall coolant without significantly altering the main magnetic circuit and overall cooling loop. Especially in motors employing oil-separated air gaps and stator-immersed liquid cooling, the ability to install high-frequency vibration components directly coupled to the coolant in the end region, and to fully utilize motor end leakage flux for auxiliary energy harvesting or local excitation, could potentially further improve the heat dissipation capacity of the end winding region and the system integration. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a motor structure that enhances cooling by synergistic effect of leakage magnetic drive and biomimetic flow guidance, so as to solve the technical problems of unstable thermal boundary layer and low local heat transfer efficiency in the end winding region of the prior art.

[0007] The technical solution adopted by this invention to solve the technical problem is as follows: A motor structure combining leakage magnetic drive and biomimetic flow guidance for enhanced cooling includes a housing, a stator, windings, an oil separator ring, and multiple vibrating diaphragm cooling units. The housing has an oil inlet and an oil outlet. The stator is located inside the housing, and the windings are mounted on the stator. The oil separator ring is located in the vicinity of the stator and rotor to restrict cooling oil from entering the air gap region. The multiple vibrating diaphragm cooling units are located at the ends of the stator or in the vicinity of the windings, each diaphragm cooling unit facing the windings and maintaining a gap with the outer surface of the windings to form a localized cooling oil action area. Each vibrating diaphragm cooling unit includes a diaphragm body, a coil assembly, and biomimetic guide ribs. The coil assembly is located inside the diaphragm body and is used to electromagnetically excite the diaphragm body under leakage magnetic induction or external power supply conditions, so that the diaphragm body generates high-frequency vibration. The diaphragm body is a vibrating elastic component that can generate periodic vibration under the action of electromagnetic force, structural vibration, or fluid pulsation inside the motor, and can apply disturbance to the cooling oil through the gap. The biomimetic guide ribs are located between adjacent vibrating diaphragm cooling units or in the non-main vibration connection area of ​​the diaphragm body, and are used to guide the disturbed cooling oil, so that the area adjacent to the winding forms a split, convergence, local vortex, wall-attached flow, and liquid renewal.

[0008] Preferably, the vibrating diaphragm cooling unit is fixedly connected to the housing via a housing support column.

[0009] Preferably, the vibrating diaphragm cooling unit is installed and positioned using an end support structure or an insulating fixing structure.

[0010] Preferably, the diaphragm body is a corrugated diaphragm structure, arranged corresponding to the position of the teeth of the stator, and the arrangement gap of the winding and the cooling oil flow channel are formed between adjacent diaphragm bodies.

[0011] Preferably, the biomimetic flow guide rib is a fish scale-shaped flow guide rib, a forked flow guide rib, a crack-type flow guide rib, or a wave-shaped micro-rib structure.

[0012] As a further enhanced cooling measure, the present invention also includes active ultrasonic diaphragm units disposed at both ends of the stator. The active ultrasonic diaphragm units are disposed toward the end windings and form a local ultrasonic oil cavity between them and the outer surface of the end windings. The active ultrasonic diaphragm units generate high-frequency vibrations under piezoelectric or magnetostrictive driving.

[0013] Preferably, the active ultrasonic diaphragm unit is driven by an external ultrasonic power supply.

[0014] Preferably, the end region corresponding to the active ultrasonic diaphragm unit is further provided with a biomimetic flow-guiding microrib or flow-guiding plate structure, which is used to guide the cooling oil after high-frequency disturbance to form directional flow and local vortices along the end winding surface.

[0015] Preferably, the oil separator ring is disposed between the stator and rotor to restrict the cooling oil from entering the air gap region, so that the cooling oil mainly acts on the stator and winding region.

[0016] The working principle of this invention is as follows: When the motor is running, the stator windings and core generate heat, which is transferred to the adjacent cooling oil through the winding insulation layer and surface. Because a near-wall oil layer with low flow velocity and high temperature tends to form near the winding surface, this near-wall oil layer increases the local thermal resistance.

[0017] The corrugated diaphragm modules arranged on both sides of the winding generate high-frequency vibrations under the excitation of the coil assembly. They also apply reciprocating disturbances to the cooling oil near the winding through the oil gaps on both sides, causing local circulation, micro-vortices, and liquid renewal processes to form near the winding surface. At the same time, biomimetic guide ribs set between adjacent diaphragms guide the disturbed cooling oil, causing it to form splitting, confluence, wall-attached flow, and local reattachment flow in the vicinity of the winding. This continuously removes the high-temperature oil layer adhering to the winding surface and promotes the replenishment of lower-temperature cooling oil to the winding surface, weakening the thermal boundary layer and enhancing local heat transfer.

[0018] In the hot spot region of the end winding, the active ultrasonic diaphragm unit generates high-frequency vibration under piezoelectric or magnetostrictive drive. The vibration is coupled to the cooling oil adjacent to the end winding through the local ultrasonic oil cavity in front of the diaphragm, making the cooling oil in this region form a stronger near-wall turbulent flow, acoustic flow and liquid renewal effect. The biomimetic flow-guiding microribs or flow-guiding plate structures set in the end region guide the cooling oil after high-frequency turbulence to form directional flow and local vortices along the surface of the end winding, thereby further enhancing the near-wall heat transfer at the end.

[0019] The oil separator ring isolates the rotor air gap area from the stator immersion oil-cooled area, preventing a large amount of cooling oil from entering the air gap, reducing additional oil churning losses, and concentrating the cooling enhancement effect on the hot spot areas of the stator and end windings.

[0020] This invention achieves a significant improvement in motor cooling performance through the synergistic effect of leakage flux drive and biomimetic current conduction. Compared with the prior art, the positive and beneficial effects of this invention are as follows: 1. The coil assembly directly senses the leakage magnetic field at the motor end to generate electricity and drive the diaphragm to vibrate. No external power supply or additional power supply device is required, which simplifies the system structure and reduces energy consumption and cost. It is especially suitable for high power density motors with limited space.

[0021] 2. The diaphragm vibration combined with the biomimetic flow guide ribs can continuously disrupt the stable near-wall oil layer on the winding surface, promote the exchange of hot and cold liquids, effectively weaken the thermal boundary layer, and improve heat transfer efficiency.

[0022] 3. The vibrating diaphragm cooling unit provides conventional cooling for the windings in the slot, while the active ultrasonic diaphragm unit enhances heat transfer for the end hot spots. The two can work independently or in combination and can be flexibly adjusted according to the motor load and thermal state.

[0023] 4. All components are located at the stator end or in the area adjacent to the winding, without occupying additional axial or radial space. The oil separator ring maintains the air gap seal, and the main magnetic circuit and overall cooling circuit do not need to be modified, making it easy to implement directly on the existing motor platform.

[0024] 5. No rotating parts, no complex control circuits, the coil assembly and diaphragm body are all made with mature technology, the biomimetic guide ribs and flow channel are integrated into the design, the long-term operation is stable and the maintenance requirements are low. Attached Figure Description

[0025] Figure 1 This is a front view of the motor structure of the present invention; Figure 2 This is a schematic diagram of the installation of the vibrating diaphragm cooling unit in this invention; Figure 3 This is a schematic diagram of the stator back diaphragm installation in this invention; Figure 4 This is a schematic diagram of the stator end diaphragm installation in this invention; Figure 5 This is an enlarged view of the stator end in this invention; Figure 6 This is a schematic diagram of the axial installation of the diaphragm on the back of the motor in this invention; Figure 7 This is an enlarged view illustrating the installation of the diaphragm on the back of the motor in this invention; In the attached figures, 1 is the diaphragm cooling unit; 2 is the winding; 3 is the stator; 4 is the housing support column; 5 is the housing; 6 is the oil inlet; 7 is the oil outlet; and 8 is the oil separator ring. Detailed Implementation

[0026] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments: Example 1, Reference Figures 1 to 7 A motor structure for enhanced cooling through leakage magnetic drive and biomimetic flow guidance includes a housing 5, a stator 3, windings 2, a housing support column 4, and an oil separator ring 8. The housing 5 has an oil inlet 6 and an oil outlet 7 to allow cooling oil to circulate within the housing 5. The oil separator ring 8 is located in the area adjacent to the stator and rotor to restrict cooling oil from entering the air gap area, ensuring that the cooling oil primarily acts on the stator 3 and windings 2. Multiple vibrating diaphragm cooling units 1 are distributed at the ends of the stator 3 or in the area adjacent to the windings 2. Each vibrating diaphragm cooling unit 1 is installed and positioned via the housing support column 4, an end support structure, or an insulating fixing structure. The vibrating diaphragm cooling unit 1 is arranged towards the windings 2 and maintains a certain gap with the outer surface of the windings 2 to form a localized cooling oil action area.

[0027] Each vibrating diaphragm cooling unit 1 includes a diaphragm body, a coil assembly, and biomimetic guide ribs. The coil assembly is located inside the diaphragm body and is used to electromagnetically excite the diaphragm body under leakage magnetic induction or external power supply conditions, causing the diaphragm body to vibrate. The diaphragm body is a vibrating elastic component that can generate periodic vibrations under the influence of electromagnetic forces, structural vibrations, or fluid pulsations within the motor, and can disturb the cooling oil through the cooling oil gap between it and the adjacent area of ​​the winding. The biomimetic guide ribs are located between adjacent vibrating diaphragm cooling units 1 or in the non-primary vibration connection area of ​​the diaphragm body, and are used to guide the disturbed cooling oil, causing the adjacent area of ​​the winding to form flow splitting, confluence, local vortices, wall-attached flow, and liquid renewal, thereby weakening the thermal boundary layer and enhancing heat dissipation. The biomimetic guide ribs are located away from the primary vibration area of ​​the diaphragm body to reduce their influence on the diaphragm vibration mode and vibration amplitude.

[0028] After entering the housing 5 through the oil inlet 6, the cooling oil flows around the stator 3 and winding 2, and flows out through the oil outlet 7, forming a continuous cooling circuit. During motor operation, the winding 2 and stator 3 generate heat, which is transferred to the cooling oil near the surface of the winding 2. When the vibrating diaphragm cooling unit 1 is working, it applies periodic vibration disturbance to the cooling oil near the winding 2, causing local flow, liquid renewal and near-wall disturbance of the cooling oil near the winding 2, thereby weakening the thermal boundary layer on the surface of the winding 2, accelerating the departure of high-temperature cooling oil from the surface of the winding 2, and promoting the replenishment of low-temperature cooling oil to the surface of the winding 2, so as to improve the heat dissipation capacity of the winding 2 and stator 3 areas.

[0029] Example 2: The difference between this example and Example 1 is that the diaphragm body is a corrugated diaphragm structure, which is arranged corresponding to the position of the teeth of the stator 3, and the arrangement gap of the winding 2 and the cooling oil flow channel are formed between adjacent diaphragm bodies.

[0030] When the motor is running, the corrugated diaphragm modules arranged on both sides of the winding generate micro-amplitude periodic vibrations under the vibration of the motor. They also apply reciprocating disturbances to the cooling oil near the winding through the oil gaps on both sides, causing local circulation, micro-vortices, and liquid renewal processes to form near the winding surface. At the same time, the biomimetic guide ribs set between adjacent diaphragms guide the disturbed cooling oil, causing it to form splitting, confluence, wall-attached flow, and local reattachment flow in the area near the winding. This continuously removes the high-temperature oil layer attached to the winding surface and promotes the replenishment of lower-temperature cooling oil to the winding surface, weakening the thermal boundary layer and enhancing local heat transfer.

[0031] Example 3. The difference between this example and Example 1 is that it also includes active ultrasonic diaphragm units disposed at both ends of the stator 3; the active ultrasonic diaphragm units are disposed toward the end windings and form a local ultrasonic action oil cavity between them and the outer surface of the end windings; the active ultrasonic diaphragm units generate high-frequency vibrations under piezoelectric or magnetostrictive drive and are driven by an external ultrasonic power supply.

[0032] In the end region, the high-frequency vibration generated by the active ultrasonic diaphragm unit is coupled to the cooling oil adjacent to the end winding through the local ultrasonic action oil cavity in front of the diaphragm, so that the cooling oil in this region forms a stronger near-wall turbulent flow, acoustic flow and liquid renewal effect; the end region is equipped with a biomimetic flow guiding microrib or flow guiding plate structure to guide the cooling oil after high-frequency turbulence to form directional flow and local vortex along the surface of the end winding, thereby further enhancing the near-wall heat transfer at the end.

[0033] The oil separator ring 8 isolates the rotor air gap area from the stator immersion oil-cooled area, preventing cooling oil from entering the air gap, reducing additional oil churning losses, and concentrating the cooling enhancement effect on the hot spot areas of the stator and end windings.

[0034] The above are merely preferred embodiments of the present invention and are not intended to limit the invention. It should be noted that any modifications, equivalent substitutions, or improvements made by those skilled in the art without departing from the principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A motor structure that combines leakage magnetic drive and biomimetic flow guidance to enhance cooling, characterized in that: The motor structure includes a housing (5), a stator (3), a winding (2), an oil separator ring (8), and multiple vibrating diaphragm cooling units (1); the housing (5) is provided with an oil inlet (6) and an oil outlet (7), the stator (3) is located inside the housing (5), the winding (2) is located on the stator (3), the oil separator ring (8) is located in the area adjacent to the stator and rotor to restrict the cooling oil from entering the air gap area, and the multiple vibrating diaphragm cooling units (1) are located at the end of the stator (3) or in the area adjacent to the winding (2). Each vibrating diaphragm cooling unit (1) is arranged facing the winding (2) and maintains a gap with the outer surface of the winding (2) to form a local cooling oil action area; Each vibrating diaphragm cooling unit (1) includes a diaphragm body, a coil assembly, and a biomimetic guide rib. The coil assembly is located inside the diaphragm body and is used to electromagnetically excite the diaphragm body under leakage magnetic induction or external power supply conditions so that the diaphragm body vibrates. The diaphragm body is a vibrating elastic component that can generate periodic vibrations under the action of electromagnetic force, structural vibration, or fluid pulsation inside the motor and to disturb the cooling oil through the gap. The biomimetic guide rib is located between adjacent vibrating diaphragm cooling units (1) or in the non-main vibration connection area of ​​the diaphragm body and is used to guide the disturbed cooling oil so that the area adjacent to the winding (2) forms a split, convergence, local vortex, wall-attached flow, and liquid renewal.

2. The motor structure according to claim 1, characterized in that: The vibrating diaphragm cooling unit (1) is fixedly connected to the housing (5) via the housing support column (4).

3. The motor structure according to claim 1, characterized in that: The vibrating diaphragm cooling unit (1) is installed and positioned by an end support structure or an insulating fixing structure.

4. The motor structure according to claim 1, characterized in that: The diaphragm body is a corrugated diaphragm structure, which is arranged corresponding to the tooth position of the stator (3). The arrangement gap of the winding (2) and the cooling oil flow channel are formed between adjacent diaphragm bodies.

5. The motor structure according to claim 1, characterized in that: The biomimetic flow guide ribs are fish-scale-shaped flow guide ribs, bifurcated flow guide ribs, crack-type flow guide ribs, or wavy micro-rib structures.

6. The motor structure according to claim 1, characterized in that: It also includes active ultrasonic diaphragm units disposed at both ends of the stator (3). The active ultrasonic diaphragm units are disposed toward the end windings and form a local ultrasonic oil cavity between them and the outer surface of the end windings. The active ultrasonic diaphragm units generate high-frequency vibrations under piezoelectric or magnetostrictive driving.

7. The motor structure according to claim 6, characterized in that: The active ultrasonic diaphragm unit is driven by an external ultrasonic power supply.

8. The motor structure according to claim 6, characterized in that: The end region corresponding to the active ultrasonic diaphragm unit is also provided with a biomimetic flow-guiding microrib or flow-guiding plate structure, which is used to guide the cooling oil after high-frequency disturbance to form directional flow and local vortices along the end winding surface.

9. The motor structure according to claim 1, characterized in that: The oil separator ring (8) is disposed between the stator and rotor to restrict the cooling oil from entering the air gap area, so that the cooling oil mainly acts on the stator (3) and winding (2) area.

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