A motor rotor-stator composite cooling system

Abstract

The application discloses a motor stator-rotor composite cooling system, which comprises a motor shell, a stator winding, a permanent magnet rotor and a rotating shaft coaxially from outside to inside, and the end of the motor shell is encapsulated through an end cover; the rotating shaft is rotatably connected with the rotating shaft through a sealing bearing; the inner side of the end cover forms a stator-rotor composite cooling bin; the iron core of the stator winding is provided with a spiral or axial extending cooling flow channel, and the motor further comprises a cooling oil inlet pipe and a cooling oil outlet pipe; the outlet end of the cooling oil inlet pipe is communicated with the middle part of the cooling flow channel; the oil inlet end of the cooling oil outlet pipe is communicated with the lowest part in the stator-rotor composite cooling bin; the end of the cooling flow channel is communicated with a rigid structure oil injection pipe; the oil injection pipe is a metal structure and is fixed with the motor shell through an auxiliary support structure; the oil injection pipe is in a zigzag shape and passes the outer edge of the coil nose of the stator winding, and the nozzle at the end of the oil injection pipe extends into the stator-rotor composite cooling bin; and the heat dissipation capacity of the motor is improved.

Description

Technical Field

[0001] This invention belongs to the field of electric motors. Background Technology

[0002] In existing oil-cooled motor cooling solutions, the stator core typically features a single axial cooling channel, with cooling oil flowing from one end to the other. This results in a significant temperature gradient along the path, making it difficult to evenly dissipate localized heat at the ends. For the rotor, cooling at the permanent magnet rotor ends relies heavily on air convection. In the coil nose area at the motor ends, where the windings are exposed, heat concentration points are common. Traditional solutions relying solely on indirect cooling or small amounts of splashed oil mist are insufficient to effectively cover these areas, easily leading to localized overheating and insulation aging. Furthermore, some oil-spraying cooling structures spray oil directly onto the rotor, causing a large amount of cooling oil to splash and escape without entering the effective heat exchange area, resulting in oil waste and affecting the reliability of the system's oil return. Summary of the Invention

[0003] Purpose of the invention: In order to overcome the shortcomings of the existing technology, the present invention provides a composite cooling system for motor stator and rotor to improve the heat dissipation capacity of motor.

[0004] Technical Solution: To achieve the above objectives, the present invention provides a stator-rotor composite cooling system for a motor, comprising a motor housing, stator windings, a permanent magnet rotor, and a rotating shaft, arranged coaxially from the outside to the inside. The ends of the motor housing are sealed by end caps. The rotating shaft is rotatably coupled with a sealed bearing. A stator-rotor composite cooling chamber is formed inside the end caps. The stator winding core has spiral or axially extending cooling channels. The system also includes a cooling oil inlet pipe and a cooling oil outlet pipe. The outlet end of the cooling oil inlet pipe connects to the middle of the cooling channels. The inlet end of the cooling oil outlet pipe connects to the lowest point within the stator-rotor composite cooling chamber. The end of the cooling channels connects to a rigid oil spray pipe, which is a metal structure and can be fixed to the motor housing by an auxiliary support structure. The oil spray pipe bends around the outer edge of the coil nose of the stator winding, and the nozzle at the end of the oil spray pipe extends into the stator-rotor composite cooling chamber.

[0005] Furthermore, the carrier of the cooling channel is a heat exchange jacket structure with a spiral flow channel that is coaxially heat-transfer matched, fixedly sleeved, or integrated into the stator winding, thereby improving the motor's heat dissipation capacity.

[0006] Furthermore, a rotor heat exchange end ring is coaxially fixedly installed at the end of the permanent magnet rotor for heat transfer.

[0007] Furthermore, the side of the rotor heat exchange end ring away from the permanent magnet rotor is integrally arranged in a circular array with several hybrid heat dissipation blades.

[0008] Furthermore, the inner ring of the rotor heat exchange end ring has an annular inner edge coaxially and integrally formed at the end away from the permanent magnet rotor, and an annular groove is formed on the side of the annular inner edge near the permanent magnet rotor; the inner ring of the annular inner edge is a conical annular surface; in the assembled state, an annular oil slinger is formed between the annular groove and the outer wall of the shaft, and a horn-shaped annular jet capture port is formed between the conical annular surface and the outer wall of the shaft, with the end of the horn-shaped annular jet capture port coaxially connected to the annular oil slinger at the end near the permanent magnet rotor; the nozzle at the end of the oil injection pipe is aligned with the horn-shaped annular jet capture port, which captures the cooling oil jet ejected from the nozzle; an oil discharge groove is vertically hollowed out at the center of the root of each mixing heat dissipation blade; several centrifugal oil suction ports are arranged in a circumferential array on the inner wall of the annular groove; several zigzag centrifugal oil passages are arranged in a circumferential array inside the rotor heat exchange end ring; one end of the zigzag centrifugal oil passage is connected to the centrifugal oil suction port, and the other end is connected to the oil discharge groove.

[0009] Furthermore, several hybrid heat dissipation blades on the rotor heat exchange end ring are coaxially aligned within the coil nose area of ​​the stator winding.

[0010] Furthermore, the centrifugal oil circuit, from the centrifugal oil suction port to the oil discharge trough, includes a centrifugal drive section, a first reversing section, a centrifugal damping section, and a second reversing section connected in series. Both the centrifugal drive section and the centrifugal damping section extend along the radial direction of the rotor heat exchange end ring, and the length of the centrifugal drive section is greater than the length of the centrifugal damping section. The first reversing section is located at the edge of the rotor heat exchange end ring, and the second reversing section is located inside the inner edge of the ring. The centrifugal oil suction port is closer to the axis of the rotor heat exchange end ring than the oil discharge trough.

[0011] Furthermore, the roots of each hybrid heat dissipation blade are integrally connected to the outer ring of the annular inner edge; the rotor heat exchange end ring is provided with several flange holes for fixing to the permanent magnet rotor.

[0012] Beneficial effects: The rotor cooling end ring of this invention is designed with a unique folding centrifugal oil circuit. This oil circuit consists of a long centrifugal drive section extending radially outward and a short centrifugal damping section extending inward after two folds. The centrifugal drive section generates a strong driving head to deliver the oil to the edge. The centrifugal damping section, being closer to the axis of rotation and having a shorter radial length, generates a damping effect against the centrifugal field, automatically limiting the oil flow rate. This keeps the cooling oil traveling at a relatively slow and stable speed within the end ring, ensuring sufficient heat exchange while effectively suppressing cavitation caused by high-speed suction and maintaining efficient liquid-phase heat transfer within the oil circuit.

[0013] Meanwhile, a horn-shaped annular jet capture port and an annular oil slinger are provided on the inner side of the rotor, which are composed of a conical annular surface and an annular groove. Together with the fixed oil injection pipe jet, the conical annular surface is used to efficiently capture the jet and form a rotating liquid ring, providing uniform and continuous oil supply conditions for each centrifugal oil suction port.

[0014] The hybrid cooling blades are located within the coil nose enclosure area, with oil discharge grooves at their roots. The fully heated oil is centrifugally ejected along the blade surface, and centrifugal airflow carries the oil droplets to form a high-speed two-phase oil mist jet that directly washes over the winding ends. This precisely enhances cooling of this traditionally localized hot spot, significantly reducing the temperature rise at the coil nose. Hot oil splashed into the composite cooling chamber automatically converges to the lowest point and is pumped away. After external cooling, it is recycled, forming a highly efficient adaptive closed-loop oil cooling system that improves the motor's power density and operational reliability. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall plan;

[0016] Figure 2 This is a schematic diagram of the rotor heat exchanger end ring structure;

[0017] Figure 3 This is a cross-sectional view of the rotor heat exchanger end ring. Detailed Implementation

[0018] The invention will now be further described with reference to the accompanying drawings.

[0019] like Figures 1 to 3 The illustrated motor stator-rotor composite cooling system includes a motor housing 16, a stator winding 15, a permanent magnet rotor 13, and a shaft 14, arranged coaxially from the outside to the inside. The end of the motor housing 16 is enclosed by an end cover 9. The shaft 14 is rotatably coupled with the end cover 9. A stator-rotor composite cooling chamber 5 is formed inside the end cover 9. The stator-rotor composite cooling chamber 5 is an annular cavity formed by the end cover 9, the motor housing 16, the stator winding 15, and the end of the permanent magnet rotor 13.

[0020] The stator winding 15 has spiral or axially extending cooling channels 2 on its core. The specific carrier of the cooling channel 2 shown in the attached figure is a heat exchange sleeve structure with spiral channels that is coaxially heat-transfer matched, fixedly sleeved, or integrally formed on the stator winding 15. It should be noted that the carrier of the cooling channel 2 can be diversified according to specific working requirements, and can also be a spiral heat exchange tube, etc., and is not limited to the structure shown in the attached figure. The inner cylindrical surface of the heat exchange sleeve structure is closely fitted with the outer cylindrical surface of the stator core to form a low thermal resistance heat transfer interface, so that the cooling oil in the cooling channel 2 can directly and efficiently absorb the heat generated by the core and winding.

[0021] It also includes a cooling oil inlet pipe 1 and a cooling oil outlet pipe 11. The outlet end of the cooling oil inlet pipe 1 is connected to the middle of the cooling channel 2. The layout of supplying oil from the middle of the channel makes the cooling oil flow symmetrically from the middle to both ends, thus balancing the axial temperature gradient of the stator core.

[0022] The oil inlet of the cooling oil outlet pipe 11 is connected to the lowest point inside the stator-rotor composite cooling chamber 5; the lowest point is provided with an oil collection groove that is inclined towards the outlet pipe 11 to facilitate the natural collection and continuous suction of the return oil.

[0023] The end of the cooling channel 2 is connected to a rigid fuel injection pipe 4. The fuel injection pipe 4 is a metal structure and can be fixed to the motor housing 16 by an auxiliary support structure. The fuel injection pipe 4 bends around the outer edge of the coil nose 6 of the stator winding 15, and the nozzle 7 at the end of the fuel injection pipe 4 extends into the stator-rotor composite cooling chamber 5. The rigid metal bending structure of the fuel injection pipe 4 avoids the coil nose 6 end winding while fixing the jet direction, ensuring that the nozzle 7 is always accurately aimed at the target capture area under vibration conditions.

[0024] The end of the permanent magnet rotor 13 is coaxially fixed with a rotor heat exchange end ring 10 for heat transfer. The rotor heat exchange end ring 10 is provided with several flange holes 22 for fixing to the permanent magnet rotor 13. The flange holes 22 are detachably connected to the permanent magnet rotor end plate by bolts to achieve heat transfer fit that is easy to maintain. The rotor heat exchange end ring 10 is preferably made of high thermal conductivity aluminum alloy or copper alloy.

[0025] The rotor heat exchange end ring 10 has several mixed heat dissipation blades 3 arranged in a circular array on the side away from the permanent magnet rotor 13. The inner ring of the rotor heat exchange end ring 10 has an annular inner edge 20 arranged coaxially on the side away from the permanent magnet rotor 13. The annular inner edge 20 forms an annular groove 12 on the side close to the permanent magnet rotor 13. The inner ring of the annular inner edge 20 is a conical annular surface 8. While throwing out cooling oil, the mixed heat dissipation blades 3 also act as centrifugal fan blades to drive the cooling airflow radially, which enhances the air convection heat transfer near the coil nose 6.

[0026] The root of each hybrid heat dissipation blade 3 is integrally connected to the outer ring of the annular inner edge 20. In the assembled state, an annular oil slinger 12a is formed between the annular groove 12 and the outer wall of the rotating shaft 14, and a horn-shaped annular jet capture port 8a is formed between the conical annular surface 8 and the outer wall of the rotating shaft 14. The end of the horn-shaped annular jet capture port 8a near the permanent magnet rotor 12 is coaxially connected to the annular oil slinger 12a. The nozzle 7 at the end of the oil injection pipe 4 is aligned with the horn-shaped annular jet capture port 8a, which captures the cooling oil jet ejected from the nozzle 7. The conical annular surface 8, with its gradually contracting conical expansion, can effectively guide and compress the jet, reducing oil splash loss. Even under the air barrier disturbance generated by the high-speed rotation of the rotor, it can still maintain high capture efficiency and reliably introduce the cooling oil into the annular oil slinger 12a.

[0027] Several mixed heat dissipation blades 3 on the rotor heat exchange end ring 10 are coaxially located within the area enclosed by the coil nose 6 of the stator winding 15; each mixed heat dissipation blade 3 has a vertically hollowed-out oil discharge groove 19 at the center of its root; several centrifugal oil suction ports 17 are arranged in a circular array on the inner wall of the ring groove 12; several folding centrifugal oil passages 18 are arranged in a circular array inside the rotor heat exchange end ring 10.

[0028] One end of the reversible centrifugal oil passage 18 is connected to the centrifugal oil suction port 17, and the other end is connected to the oil discharge groove 19. The oil discharge groove 19 is located in the neutral zone at the root of the blade, so that the discharged cooling oil immediately spreads radially along the blade surface under the action of centrifugal force to form a thin film, which not only cools the blade body evenly, but also provides an initial liquid film for the formation of radial oil mist.

[0029] The centrifugal oil circuit 18, from the centrifugal oil suction port 17 to the oil discharge trough 19, includes a centrifugal drive section 18a, a first reversing section 18b, a centrifugal damping section 18c, and a second reversing section 18d connected in series. Both the centrifugal drive section 18a and the centrifugal damping section 18c extend along the radial direction of the rotor heat exchange end ring 10, and the length of the centrifugal drive section 18a is greater than the length of the centrifugal damping section 18c. The first reversing section 18b is located at the edge of the rotor heat exchange end ring 10, and the second reversing section 18d is located within the inner edge 20 of the ring. The centrifugal oil suction port 17 is closer to the axis of the rotor heat exchange end ring 10 than the oil discharge trough 19. The centrifugal drive section 18a generates strong centrifugal drive pressure, which accelerates the oil towards the first reversal section 18b at the edge. After turning, it enters the centrifugal damping section 18c. Since the radial length of the centrifugal damping section 18c is relatively short, there is a reverse pressure gradient between the direction of oil flow and the centrifugal force field in this section, which generates a significant throttling damping effect, automatically limiting the flow rate, ensuring that the oil maintains a sufficient residence time in the rotor heat exchange end ring 10 to fully absorb the rotor heat, while preventing air from being drawn into the oil circuit due to excessive flow rate, and keeping the oil circuit full of liquid cooling medium.

[0030] Working principle:

[0031] During operation, the cooling oil inlet pipe 1 continuously pressurizes the relatively cold cooling oil into the cooling channel 2 at a certain pressure, and continuously absorbs the heat from the iron core of the stator winding 15; the cooling oil flows axially in the spiral channel, forming a large-area convective heat exchange with the iron core, and efficiently removes the heat generated by the main heat source of the stator.

[0032] Subsequently, the cooling oil in the cooling channel 2 is pressurized and enters the oil injection pipe 4. It is then continuously ejected from the nozzle 7 at the end of the oil injection pipe 4 in the form of a jet, aiming at the horn-shaped annular jet capture port 8a. This allows the horn-shaped annular jet capture port 8a to capture the cooling oil jet ejected from the nozzle 7. The oil supply pressure is matched with the jet velocity to ensure that the jet momentum is sufficient to penetrate the airflow barrier formed by the rotor rotation and stably inject into the capture port.

[0033] The horn-shaped annular jet capture port 8a captures cooling oil, which, under the action of its own inertia, flows further into the annular oil slinger 12a. The cooling oil entering the annular oil slinger 12a rotates with the rotor under the constraint of viscosity, so that the cooling oil is evenly distributed in the annular oil slinger 12a in a swirling manner, forming a stable rotating liquid ring. This liquid ring provides uniform oil intake conditions for each centrifugal oil suction port 17, avoiding local oil cut-off.

[0034] Subsequently, driven by centrifugal force, the cooling oil in the annular oil-throwing chamber 12a flows sequentially through the centrifugal oil inlet 17, the centrifugal drive section 18a, the first return section 18b, the centrifugal damping section 18c, and the second return section 18d, and is finally discharged from the oil discharge trough 19 to the root of each mixing heat dissipation blade 3. The relatively large radial length of the centrifugal drive section 18a provides sufficient driving energy to the oil, while the centrifugal force component in the flow direction of the centrifugal damping section 18c exhibits resistance characteristics, thus subjecting the liquid flowing within the centrifugal damping section 18c to centrifugal resistance. The force acts as a centrifugal damper on the oil flow rate, allowing the zigzag centrifugal oil passage 18 to travel at a slower flow rate. This ensures that the oil fully absorbs the heat from the rotor heat exchange end ring 10. At the same time, it prevents the cooling oil captured in the annular oil slinger 12a from being thrown out too quickly through the zigzag centrifugal oil passage 18, which would otherwise mix with a large amount of air with low heat exchange efficiency. This effectively suppresses the cavitation phenomenon in the oil passage that may occur due to high-speed oil throwing, and ensures that the zigzag centrifugal oil passage 18 always maintains a high heat transfer coefficient in the liquid phase.

[0035] Meanwhile, the cooling oil discharged from the oil outlet 19 to the root of each mixed heat dissipation blade 3 adheres to the surface of the mixed heat dissipation blade 3 and, under the influence of centrifugal force and nearby centrifugal airflow, is radially and evenly thrown outwards towards the inner ring of the coil nose 6 of the stator winding 15. At the same time, the cooling oil centrifugally thrown outwards from the surface of each mixed heat dissipation blade 3 continuously and efficiently removes the heat from each mixed heat dissipation blade 3, so that the coil nose 6 continuously receives the diffuse centrifugal splashing cooling oil and centrifugal air, thereby allowing the heat of the coil nose 6 to be fully absorbed by the centrifugal wind and centrifugal splashing cooling oil. The centrifugal wind driven by the mixed heat dissipation blade 3 carries fine oil droplets to form a high-speed oil mist two-phase jet, which directly washes the end winding surface of the coil nose 6, greatly improving the cooling intensity of this traditional local hot spot, effectively reducing the winding temperature rise and extending the insulation life.

[0036] The cooling oil, which has fully absorbed heat and splashed onto various parts of the stator-rotor composite cooling chamber 5, automatically flows to the lowest point within the chamber under gravity and is continuously drawn away by the cooling oil outlet pipe 11, thus achieving a highly efficient cooling cycle. After passing through an external cooling and filtration unit, the drawn-out hot oil is resupplyed to the cooling oil inlet pipe 1, forming a closed-loop oil cooling cycle system. This allows the motor to maintain thermal balance under continuous high-load conditions, significantly improving the motor's power density and operational reliability.

[0037] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A motor stator-rotor compound cooling system, characterized by: The motor housing (16), stator winding (15), permanent magnet rotor (13), and shaft (14) are coaxial from the outside to the inside. The end of the motor housing (16) is sealed by an end cover (9). The shaft (14) is rotatably engaged with the shaft (14) through a sealed bearing. A stator-rotor composite cooling chamber (5) is formed inside the end cover (9). The stator winding (15) has a spiral or axially extending cooling channel (2) on its core, and also includes a cooling oil inlet pipe (1) and a cooling oil outlet pipe (11). The outlet end of the cooling oil inlet pipe (1) is connected to the middle of the cooling channel (2); the inlet end of the cooling oil outlet pipe (11) is connected to the lowest point in the stator-rotor composite cooling chamber (5); the end of the cooling channel (2) is connected to the rigid structure oil injection pipe (4); the oil injection pipe (4) is bent around the outer edge of the coil nose (6) of the stator winding (15), and the nozzle (7) at the end of the oil injection pipe (4) extends into the stator-rotor composite cooling chamber (5).

2. A rotor-stator composite cooling system for an electric machine according to claim 1, characterized in that: The carrier of the cooling channel (2) is a heat exchange jacket structure with a spiral flow channel that is coaxially heat-transfer matched, fixedly sleeved, or integrated on the stator winding (15).

3. The motor stator-rotor composite cooling system according to claim 1, characterized in that: The permanent magnet rotor (13) is coaxially fixed with a rotor heat exchange end ring (10) at its end.

4. The motor stator-rotor composite cooling system according to claim 3, characterized in that: The rotor heat exchange end ring (10) is arranged in a circular array on the side away from the permanent magnet rotor (13) with several mixed heat dissipation blades (3).

5. The motor stator-rotor composite cooling system according to claim 4, characterized in that: The inner ring of the rotor heat exchange end ring (10) is coaxially and integrally provided with an annular inner edge (20) at the end away from the permanent magnet rotor (13). An annular groove (12) is formed on the side of the annular inner edge (20) close to the permanent magnet rotor (13). The inner ring of the annular inner edge (20) is a conical annular surface (8). In the assembled state, an annular oil slinger (12a) is formed between the annular groove (12) and the outer wall of the rotating shaft (14), and a horn-shaped annular jet capture port (8a) is formed between the conical annular surface (8) and the outer wall of the rotating shaft (14). The horn-shaped annular jet capture port (8a) is coaxially connected to the annular oil slinger (12a) at one end near the permanent magnet rotor (12). The nozzle (7) at the end of the oil injection pipe (4) is aligned with the horn-shaped annular jet capture port (8a), and the horn-shaped annular jet capture port (8a) captures the cooling oil jet ejected from the nozzle (7). Each of the hybrid heat dissipation blades (3) has a vertically hollowed-out oil discharge groove (19) at the center of its root; the inner wall of the annular groove (12) is provided with a number of centrifugal oil suction ports (17) arranged in a circular array; the rotor heat exchange end ring (10) is provided with a number of zigzag centrifugal oil passages (18) arranged in a circular array; one end of the zigzag centrifugal oil passage (18) is connected to the centrifugal oil suction port (17), and the other end is connected to the oil discharge groove (19).

6. The motor stator-rotor composite cooling system according to claim 5, characterized in that: Several mixed heat dissipation blades (3) on the rotor heat exchange end ring (10) are coaxial as a whole within the area enclosed by the coil nose (6) of the stator winding (15).

7. The motor stator-rotor composite cooling system according to claim 5, characterized in that: The centrifugal oil circuit (18) from the centrifugal oil inlet (17) to the oil outlet (19) includes a centrifugal drive section (18a), a first reversing section (18b), a centrifugal damping section (18c), and a second reversing section (18d) connected in series. Both the centrifugal drive section (18a) and the centrifugal damping section (18c) extend along the radial direction of the rotor heat exchange end ring (10), and the length of the centrifugal drive section (18a) is greater than the length of the centrifugal damping section (18c). The first reversing section (18b) is located at the edge of the rotor heat exchange end ring (10), and the second reversing section (18d) is located within the inner edge (20) of the ring. The centrifugal oil inlet (17) is closer to the axis of the rotor heat exchange end ring (10) than the oil outlet (19).

8. The motor stator-rotor composite cooling system according to claim 5, characterized in that: The root of each hybrid heat dissipation blade (3) is integrally connected to the outer ring of the annular inner edge (20); the rotor heat exchange end ring (10) is provided with several flange holes (22) for fixing to the permanent magnet rotor (13); the oil injection pipe (4) is a metal structure and can be fixed to the motor housing (16) through an auxiliary support structure.

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