Oil cooling structure

Abstract

The present invention belongs to the technical field of high-power density rotating motor cooling technology, and specifically relates to an oil-cooled heat dissipation structure, comprising: an open end ring structure, an end plate structure, and a cooling pipeline. The oil-cooled heat dissipation structure utilizes the open end ring, the motor housing, and the end cover to form an end annular space, and the sealing effect of the end annular space is ensured by the sealing ring and mechanical dimensions to prevent leakage of cooling oil. The end annular space and the intermediate cooling pipeline structure ensure that the stator winding and stator core are completely immersed in cooling oil. The cooling oil is used to directly cool the stator core and winding, reducing the intermediate heat conduction link and significantly improving the heat dissipation effect. In addition, the coolant flow rate can be adjusted to match the heat load. The more heat, the greater the cooling flow rate, and the less heat, the smaller the cooling oil flow rate.

Description

Technical Field

[0001] The present invention belongs to the technical field of high-power-density rotating motor cooling, and specifically relates to an oil-cooling heat dissipation structure, and more particularly to a stator oil cooling system and a rotor air cooling system for a high-power-density open-slot rotating motor. The invention has an excellent effect on improving the heat dissipation efficiency of the high-power-density rotating motor and reducing the internal temperature rise of the motor. Background Art

[0002] Rotating electric machines are increasingly used in transportation, defense, and other fields. As load demands for higher power levels and space requirements for rotating electric machines continue to rise, the power density and heat flux of these machines are increasing, and the heat dissipation requirements for high-power-density rotating electric machines are also increasing. When a motor operates under load, losses primarily include stator iron loss, winding copper loss, mechanical loss, and stray loss. Copper loss in the stator winding is the primary source of motor loss. Due to the high thermal resistance of the main insulation within the slots, the stator winding generates significant heat, resulting in the highest operating temperature rise.

[0003] Existing cooling methods for high-power-density rotating motors primarily include air cooling, water cooling, and oil cooling. Lower-power-density motors generally use air cooling; high-power-density rotating motors, with their high heat flux and high design heat load, often utilize water or oil cooling. Oil cooling methods primarily include direct oil cooling and indirect oil cooling. Direct oil cooling dissipates heat through direct contact between the cooling oil and the windings and core. Direct oil cooling can be further divided into oil immersion cooling and oil spray cooling. Indirect oil cooling removes heat from the motor through heat exchange between flowing oil and the heat source. However, indirect oil cooling methods often use oil circuits located within the stator core or motor shaft, making them unable to directly cool the heat source. Heat in the windings must be transferred to the cooling oil through the main insulation within the slots and the stator core. This long transfer path increases thermal resistance and results in low heat dissipation efficiency. By optimizing the oil circuit design based on existing oil cooling methods, the heat dissipation efficiency of oil cooling can be effectively improved, reducing the operating temperature rise of the rotating motor windings.

[0004] A rotating electric machine primarily consists of a stator core, stator windings, a rotor core, a motor housing, end caps, and a rotating shaft. The stator core is defined by slots, within which the stator windings reside. Stator core slots are primarily classified into open and closed slots. Open slots are open, preventing the stator core's inner surface from forming a perfectly smooth cylindrical surface. Closed slots are closed, resulting in a perfectly smooth cylindrical surface. Due to insulation requirements, the stator slots are equipped with in-slot main insulation. This insulation has a high thermal resistance, and the insulation material is a poor conductor of heat, hindering the outward flow of heat from the slot. An air gap exists between the inner diameter of the stator and the outer diameter of the rotor, creating an extremely small gap. During motor operation, the rotor rotates at high speed, creating turbulent air flow within the air gap. Furthermore, due to the slot openings, localized turbulence forms at the slot openings, further complicating and increasing wind friction losses in the motor rotor. The motor stator core is installed on the motor casing, and the end covers on both sides of the motor and the motor casing form a closed space inside the motor.

[0005] Rotating motors are increasingly demanding higher power density, and oil-cooled motors are a current research hotspot. Oil cooling offers excellent insulation performance. Cooling oil has a lower freezing point than water, making it less likely to condense at low temperatures, while having a higher boiling point than water, making it less likely to boil at high temperatures.

[0006] Patent CN112821604A discloses a heat dissipation structure for an oil-cooled flat wire motor and a motor. The heat dissipation structure includes at least two groups of oil spray nozzles on a side near the stator winding, with multiple groups arranged axially along the stator winding. At least one group of the multiple groups of oil spray nozzles corresponds to the end of the stator winding, and at least one group of the multiple groups of oil spray nozzles corresponds to the end of the stator winding near the stator core. This allows the cooling medium to be sprayed onto the end of the stator winding and a position near the end of the stator core, allowing the cooling medium to flow from the end of the stator winding to the stator core and from the position near the end of the stator core toward the end of the stator winding, and to flow through the inner layer of the stator winding. This invention utilizes the shape of the stator winding and the gravity of the cooling medium to change the cooling medium's flow from random to directional, thereby increasing the contact area between the cooling medium and the stator winding and improving the heat dissipation performance of the motor.

[0007] Spraying cooling oil onto the stator windings through the nozzles doesn't allow for accurate cooling oil flow, precise control of heat dissipation, or matching cooling oil flow to heat output. Furthermore, due to the relatively fixed angle of the nozzles, it's impossible to guarantee that the cooling oil reaches the highest temperature point, thus failing to ensure optimal cooling.

[0008] Invention patent CN112769294A provides an oil-cooled flat wire motor heat dissipation structure and motor, including a slot wedge, which is inserted into the slot opening of the stator core slot. The slot wedge includes a slot wedge body and a spoiler, and the spoiler is provided on one side of the slot wedge body; there are multiple spoilers, and the multiple spoilers are all provided on the same side of the slot wedge body, and the multiple spoilers are arranged along the length direction of the slot wedge body. The cooling medium is sprayed onto the slot wedge body and flows along the surface of the slot wedge body. The flowing cooling medium is divided into multiple flow layers by the spoiler, and small-area vortices are formed behind the spoiler to keep the cooling medium flowing in a turbulent state. The beneficial effect of the present invention is that the spoiler is added to turbulently flow the cooling medium between the two coils in the slot. After the cooling medium flows through the spoiler, a small-area vortex appears behind the spoiler, and the cooling medium in the slot flows into a turbulent state, thereby improving the convective heat transfer capacity between the cooling medium and the coil, and improving the heat dissipation performance of the motor.

[0009] When the fluid flow rate inside the slot wedge is high, the fluid flow state is turbulent and the flow state is disordered, which causes impact on the winding in the slot. Due to the existence of turbulence, the actual flow rate is greater than the required flow rate, resulting in waste of cooling oil flow. Summary of the Invention

[0010] (1) Technical issues to be solved

[0011] The technical problem to be solved by the present invention is: how to propose a cooling structure to solve the problems of stator oil cooling and rotor air cooling of high power density open slot rotating motors, which is required to not only improve the stator oil cooling effect and reduce the temperature rise of the motor windings, but also improve the air flow state in the air gap between the stator and the rotor, and reduce the temperature rise of the rotor surface.

[0012] (2) Technical solution

[0013] To solve the above technical problems, the present invention provides an oil cooling and heat dissipation structure. The stator core 2 of the motor to which the oil cooling and heat dissipation structure is applicable is a cylindrical structure. A plurality of stator slots 1 are evenly distributed on the stator core 2. The stator slots are open slots. The open slots make the inner surface of the stator core a non-complete and smooth cylindrical surface.

[0014] Part of the winding is located in the stator slot 1, and part of the winding is exposed outside the two ends of the stator core 2; the winding exposed at the two ends of the stator core 2 is the end winding 3, the stator slot 1 is provided with a main insulating material 4, and the innermost part is the slot winding 5. The slot winding 5 and the main insulating material 4 are both located inside the stator slot 1;

[0015] The oil cooling and heat dissipation structure includes: an open end ring structure 6, an end plate structure 7, and a cooling pipeline 8;

[0016] The open end ring structure 6 is configured as a cylindrical body, and two annular end plate structures 7 are provided on its outer surface, which are parallel to each other and extend radially outward. The two end plate structures 7 are parallel to each other and are annular structures extending radially outward on the outer surface of the cylinder.

[0017] The cooling pipe 8 is a hollow structure. The number of cooling pipes 8 is consistent with the number of stator slots 1. The shape of the cooling pipe 8 is consistent with the shape of the opening of the stator slot 1. Between the two end plate structures 7, multiple cooling pipes 8 are connected together through the two end plate structures 7 to form a complete annular structure.

[0018] Inside the open end ring structure 6, a spiral protrusion 9 is provided on the inner surface, which is spirally wound along the axial direction of the inner surface. In the axial direction, the inner diameter of the open end ring structure 6 is divided into three parts: the part between the two end plate structures 7 is the middle part, and its inner diameter is defined as R2; the two parts on both sides of the middle part are defined as the end parts, and the inner diameters of the end parts are the same, defined as R1. The setting is: R1 is smaller than R2, so that the cylinder thickness of the end parts of the open end ring structure 6 is greater than the cylinder thickness of the middle part.

[0019] The open end ring structure 6, the end plate structure 7, the motor end cover 10 and the housing 11 form an annular enclosed space 12. The end windings 3 of the motor are completely located in the annular enclosed space 12. The annular enclosed spaces 12 on both sides of the motor are connected by the cooling pipe 8 in the middle. The in-slot windings 5 ​​of the motor are located in the cooling pipe 8, and the end windings 3 are located in the annular enclosed space 12. Therefore, the motor windings are completely located in the annular enclosed space 12.

[0020] The motor end cover 10 is provided with an oil inlet 14 for connecting to an oil inlet pipeline, and the motor end cover 10 is also provided with an oil outlet 15 for connecting to an oil outlet pipeline; wherein, the oil inlet 14 is located at the upper part of the motor, and the oil outlet 15 is located at the lower part of the motor to facilitate the flow of cooling oil.

[0021] The two end plate structures 7 are made of insulating material. The two end plate structures 7 can serve as insulating plates on both sides of the stator core 2 of the motor, and can also play a connecting role for connecting multiple cooling pipes 8.

[0022] The cooling pipe 8 is made of insulating material, and the thickness of the pipe is consistent with the thickness of the main insulating material 4 in the motor slot, and can be used as an insulating component in the stator slot 1.

[0023] The structure of the cooling pipeline 8 is configured to ensure that the stator slots 1 of the motor stator core 2 are filled.

[0024] After the oil cooling and heat dissipation structure is installed, it covers the inner surface of the stator core 2. The inner cylindrical surface of the oil cooling and heat dissipation structure is provided with the inner surface spiral protrusion 9, which together with the outer surface of the rotor forms a spiral air duct;

[0025] The air gap space of the motor is small, and the minimum inner diameter of the two end parts of the open end ring structure 6 is set to be smaller than the minimum inner diameter of the part located in the air gap of the motor between the two middle end plate structures 7, thereby ensuring that the cylindrical oil cooling structure does not interfere with the rotor after installation.

[0026] Among them, the open end ring structures 6 on both sides play the role of receiving cooling oil. The open end ring structures on both sides are thick to ensure that they are strong enough. The annular enclosed space 12 at the end can operate safely after being filled with cooling oil; at the same time, the oil-cooling heat dissipation structure can completely isolate the stator space and the rotor space of the motor without affecting each other.

[0027] When the motor is running, cooling oil flows from the oil inlet 14 into the annular enclosed spaces 12 on both sides, fills the annular enclosed spaces 12 and the middle cooling pipe 8, and finally flows out from the oil outlet 15 at the bottom of the casing; the motor's slot windings 5 ​​and end windings 3 are completely immersed in the cooling oil, and the heat generated by the windings is transferred and taken away by the flow of cooling oil. The cooling oil directly cools the heat source, reduces the intermediate heat conduction link, reduces the thermal resistance, and greatly improves the heat dissipation effect.

[0028] Among them, the flow rate of cooling oil can be adjusted as the motor loss changes. When the motor load increases, the winding current increases, and the winding part heats up seriously, increasing the cooling oil flow rate can effectively reduce the temperature rise of the stator winding. When the motor load decreases, reducing the cooling oil flow rate can not only ensure the cooling effect, but also save the amount of cooling oil, so that the cooling oil flow rate is matched with the heat load.

[0029] When the motor is running under load conditions, the motor rotor rotates at high speed, and the air flow on the rotor surface is disordered, which is not conducive to heat dissipation on the rotor surface. At the same time, due to the influence of the opening of the stator slot 1 of the stator core 2, local air turbulence is formed at the slot opening, further increasing the wind friction loss on the rotor surface.

[0030] The oil-cooling and heat dissipation structure covers the inner surface of the stator core 2, covering the openings of the stator slots 1. A spiral wind pattern forms on the inner surface of the oil-cooling and heat dissipation structure. When the motor rotor rotates at high speed, air flowing into the air gap from one end of the motor flows along the spiral channel in the air gap to the other end. The spiral channel acts as a guide, ensuring unidirectional air flow and improving the air flow state within the air gap. After flowing out of the air gap, the air can exchange heat with the end rings, transferring the heat to the cooling oil in the end rings.

[0031] Among them, when the motor speed is low, the relative speed between the motor rotor and the spiral pipe is small, the axial air flow velocity is slow, and the friction between the air in the air gap and the rotor surface is small; when the motor speed increases, the relative speed between the motor rotor and the spiral pipe increases, the axial air flow velocity becomes larger, and the rotor surface loss increases; the air flow velocity and the rotor wind friction loss can be automatically matched to achieve the purpose of cooling the rotor surface.

[0032] (3) Beneficial effects

[0033] Compared to existing technologies, the cooling structure of the present invention, after installation, utilizes open end rings, the motor housing, and the end cap to form an annular space at the end. Sealing rings and mechanical dimensions ensure the sealing of this annular space, preventing cooling oil leakage. The annular space and intermediate cooling piping ensure that the stator windings and stator core are completely immersed in cooling oil. The cooling oil directly cools the stator core and windings, reducing intermediate heat transfer steps and significantly improving heat dissipation. Furthermore, the coolant flow rate can be adjusted to match the heat load: greater heat loads increase the cooling flow rate, while lower heat loads reduce the cooling oil flow rate.

[0034] Intermediate cooling lines are made of insulating material. They serve as both cooling oil circulation lines and primary insulation for the windings within the slots, thus performing multiple functions. The shape of the intermediate cooling lines matches the stator core slot profile, offering not only square shapes but also other stator core slot profiles. The number of intermediate cooling lines matches the number of stator slots, ensuring cooling for all windings within the slots. The shape of the intermediate cooling lines matches the slot profile, ensuring installation feasibility. The intermediate cooling lines are connected via end plates made of insulating material, serving both as connectors and as end plates for the motor's stator core.

[0035] After the intermediate cooling pipeline is installed, the stator core slot opening is filled, and the inner surface forms a complete smooth cylindrical surface to avoid air turbulence caused by the high-speed rotation of the rotor. The intermediate cooling pipeline forms a smooth cylindrical surface on the inner surface of the stator core and has a spiral passage, which provides direction for the air flow inside the air gap, improves the heat dissipation effect, and is beneficial to reducing the temperature rise of the rotor surface. At the same time, the axial flow speed of the air inside the air gap is also matched with the rotor speed, which is beneficial to the heat dissipation of the rotor surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1a and Figure 1b This is the stator core structure diagram.

[0037] Figure 2 Schematic diagram of stator opening slots.

[0038] Figure 3a and Figure 3b This is the stator assembly drawing.

[0039] Figure 4 Schematic diagram of heat dissipation structure.

[0040] Figure 5 This is a partial diagram of the cooling pipeline.

[0041] Figure 6 This is a diagram of the cooling structure cylinder.

[0042] Figure 7 This is a cross-sectional view of the motor assembly structure.

[0043] Figure 8 This is a schematic diagram of the cooling pipe and stator assembly.

[0044] Figure 9 This is a schematic diagram of the cooling pipe and stator assembly.

[0045] Figure 10 This is a cross-section view of the assembly boundary. DETAILED DESCRIPTION

[0046] In order to make the purpose, content, and advantages of the present invention more clear, the specific implementation methods of the present invention are further described in detail below with reference to the accompanying drawings and examples.

[0047] In response to the heat dissipation requirements of high-power-density rotating motors, the present invention proposes an oil-cooling heat dissipation structure based on stator oil cooling and rotor air cooling. The oil-cooling structure immerses the motor windings in the oil circuit, effectively improving the heat dissipation effect, while optimizing the air flow state inside the air gap and reducing the temperature rise on the rotor surface.

[0048] To solve the above technical problems, the present invention provides an oil cooling and heat dissipation structure. The stator core 2 of the motor to which the oil cooling and heat dissipation structure is applicable is a cylindrical structure. A plurality of stator slots 1 are evenly distributed on the stator core 2. The stator slots are open slots. The open slots make the inner surface of the stator core a non-complete and smooth cylindrical surface.

[0049] Part of the winding is located in the stator slot 1, and part of the winding is exposed outside the two ends of the stator core 2; the winding exposed at the two ends of the stator core 2 is the end winding 3, the stator slot 1 is provided with a main insulating material 4, and the innermost part is the slot winding 5. The slot winding 5 and the main insulating material 4 are both located inside the stator slot 1;

[0050] The oil cooling and heat dissipation structure includes: an open end ring structure 6, an end plate structure 7, and a cooling pipeline 8;

[0051] The open end ring structure 6 is configured as a cylindrical body, and two annular end plate structures 7 are provided on its outer surface, which are parallel to each other and extend radially outward. The two end plate structures 7 are parallel to each other and are annular structures extending radially outward on the outer surface of the cylinder.

[0052] The cooling pipe 8 is a hollow structure. The number of cooling pipes 8 is consistent with the number of stator slots 1. The shape of the cooling pipe 8 is consistent with the shape of the opening of the stator slot 1. Between the two end plate structures 7, multiple cooling pipes 8 are connected together through the two end plate structures 7 to form a complete annular structure.

[0053] Inside the open end ring structure 6, a spiral protrusion 9 is provided on the inner surface, which is spirally wound along the axial direction of the inner surface. In the axial direction, the inner diameter of the open end ring structure 6 is divided into three parts: the part between the two end plate structures 7 is the middle part, and its inner diameter is defined as R2; the two parts on both sides of the middle part are defined as the end parts, and the inner diameters of the end parts are the same, defined as R1. The setting is: R1 is smaller than R2, so that the cylinder thickness of the end parts of the open end ring structure 6 is greater than the cylinder thickness of the middle part.

[0054] The open end ring structure 6, the end plate structure 7, the motor end cover 10 and the housing 11 form an annular enclosed space 12. The end windings 3 of the motor are completely located in the annular enclosed space 12. The annular enclosed spaces 12 on both sides of the motor are connected by the cooling pipe 8 in the middle. The in-slot windings 5 ​​of the motor are located in the cooling pipe 8, and the end windings 3 are located in the annular enclosed space 12. Therefore, the motor windings are completely located in the annular enclosed space 12.

[0055] The motor end cover 10 is provided with an oil inlet 14 for connecting to an oil inlet pipeline, and the motor end cover 10 is also provided with an oil outlet 15 for connecting to an oil outlet pipeline; wherein, the oil inlet 14 is located at the upper part of the motor, and the oil outlet 15 is located at the lower part of the motor to facilitate the flow of cooling oil.

[0056] The two end plate structures 7 are made of insulating material. The two end plate structures 7 can serve as insulating plates on both sides of the stator core 2 of the motor, and can also play a connecting role for connecting multiple cooling pipes 8.

[0057] The cooling pipe 8 is made of insulating material, and the thickness of the pipe is consistent with the thickness of the main insulating material 4 in the motor slot, and can be used as an insulating component in the stator slot 1.

[0058] The structure of the cooling pipeline 8 is configured to ensure that the stator slots 1 of the motor stator core 2 are filled.

[0059] After the oil cooling and heat dissipation structure is installed, it covers the inner surface of the stator core 2. The inner cylindrical surface of the oil cooling and heat dissipation structure is provided with the inner surface spiral protrusion 9, which together with the outer surface of the rotor forms a spiral air duct;

[0060] The air gap space of the motor is small, and the minimum inner diameter of the two end parts of the open end ring structure 6 is set to be smaller than the minimum inner diameter of the part located in the air gap of the motor between the two middle end plate structures 7, thereby ensuring that the cylindrical oil cooling structure does not interfere with the rotor after installation.

[0061] Among them, the open end ring structures 6 on both sides play the role of receiving cooling oil. The open end ring structures on both sides are thick to ensure that they are strong enough. The annular enclosed space 12 at the end can operate safely after being filled with cooling oil; at the same time, the oil-cooling heat dissipation structure can completely isolate the stator space and the rotor space of the motor without affecting each other.

[0062] When the motor is running, cooling oil flows from the oil inlet 14 into the annular enclosed spaces 12 on both sides, fills the annular enclosed spaces 12 and the middle cooling pipe 8, and finally flows out from the oil outlet 15 at the bottom of the casing; the motor's slot windings 5 ​​and end windings 3 are completely immersed in the cooling oil, and the heat generated by the windings is transferred and taken away by the flow of cooling oil. The cooling oil directly cools the heat source, reduces the intermediate heat conduction link, reduces the thermal resistance, and greatly improves the heat dissipation effect.

[0063] Among them, the flow rate of cooling oil can be adjusted as the motor loss changes. When the motor load increases, the winding current increases, and the winding part heats up seriously, increasing the cooling oil flow rate can effectively reduce the temperature rise of the stator winding. When the motor load decreases, reducing the cooling oil flow rate can not only ensure the cooling effect, but also save the amount of cooling oil, so that the cooling oil flow rate is matched with the heat load.

[0064] When the motor is running under load conditions, the motor rotor rotates at high speed, and the air flow on the rotor surface is disordered, which is not conducive to heat dissipation on the rotor surface. At the same time, due to the influence of the opening of the stator slot 1 of the stator core 2, local air turbulence is formed at the slot opening, further increasing the wind friction loss on the rotor surface.

[0065] The oil-cooling and heat dissipation structure covers the inner surface of the stator core 2, covering the openings of the stator slots 1. A spiral wind pattern forms on the inner surface of the oil-cooling and heat dissipation structure. When the motor rotor rotates at high speed, air flowing into the air gap from one end of the motor flows along the spiral channel in the air gap to the other end. The spiral channel acts as a guide, ensuring unidirectional air flow and improving the air flow state within the air gap. After flowing out of the air gap, the air can exchange heat with the end rings, transferring the heat to the cooling oil in the end rings.

[0066] Among them, when the motor speed is low, the relative speed between the motor rotor and the spiral pipe is small, the axial air flow velocity is slow, and the friction between the air in the air gap and the rotor surface is small; when the motor speed increases, the relative speed between the motor rotor and the spiral pipe increases, the axial air flow velocity becomes larger, and the rotor surface loss increases; the air flow velocity and the rotor wind friction loss can be automatically matched to achieve the purpose of cooling the rotor surface.

[0067] Example 1

[0068] This embodiment provides an oil cooling and heat dissipation structure. The stator core 2 of the motor to which the oil cooling and heat dissipation structure is applicable is a cylindrical structure. The axial view is as follows: Figure 1b As shown, a plurality of stator slots 1 are evenly distributed on the stator core 2, and the stator slot type is an open slot. The open slot type makes the inner surface of the stator core a non-complete smooth cylindrical surface; Figure 2 This is an enlarged view of the stator slot. The stator assembly structure is as follows Figure 3a and Figure 3b As shown, it includes a stator core 2 and windings, part of which is located in the stator slot 1, and part of which is exposed outside the two ends of the stator core. The windings exposed at both ends of the stator core 2 are end windings 3. The stator slot 1 has a main insulating material 4, and the innermost part is the in-slot winding 5. The in-slot winding 5 and the main insulating material 4 are both located inside the stator slot 1.

[0069] like Figure 4 As shown, the oil cooling and heat dissipation structure includes: an open end ring structure 6, an end plate structure 7, and a cooling pipeline 8;

[0070] The open end ring structure 6 is configured as a cylindrical body, and two parallel end plate structures 7 extending radially are provided on its outer surface; the two end plate structures 7 are made of insulating material and can serve as insulating plates on both sides of the stator core 2 of the motor, and can also serve as a connection for connecting multiple cooling pipes 8;

[0071] The cooling pipe 8 is a hollow structure. The number of cooling pipes 8 is consistent with the number of stator slots 1. The shape of the cooling pipe 8 is consistent with the shape of the opening of the stator slot 1. Multiple cooling pipes 8 are connected together through two end plate structures 7 to form a complete annular structure. A partial enlarged view of the cooling pipe 8 is shown in FIG. Figure 5 The cooling pipe 8 is made of insulating material, and the thickness of the pipe is consistent with the thickness of the main insulating material 4 in the motor slot, and can be used as an insulating component in the stator slot 1;

[0072] Inside the open end ring structure 6, there is a spiral protrusion 9 on the inner surface, which is spirally wound along the axial direction of the inner surface; the cross section of the cooling structure is as follows Figure 6 As shown, in the axial direction, the inner diameters of the two end portions of the open end ring structure are set to be smaller than the inner diameter of the portion between the two end plate structures 7, that is, R1 is smaller than R2.

[0073] After the oil cooling structure is installed, the final assembly structure is as follows Figure 7 shown.

[0074] The open end ring structure 6, the end plate structure 7, the motor end cover 10 and the housing 11 form an annular enclosed space 12. The end windings 3 of the motor are completely located in the annular enclosed space 12. The annular enclosed spaces 12 on both sides of the motor are connected by the cooling pipe 8 in the middle. The in-slot windings 5 ​​of the motor are located in the cooling pipe 8, and the end windings 3 are located in the annular enclosed space 12. Therefore, the motor windings are completely located in the annular enclosed space 12.

[0075] The cooling pipe 8 is structured to ensure that the stator slots 1 of the motor stator core 2 are filled. Figure 8 13 as shown; Figure 9 As shown, the motor end cover 10 is provided with an oil inlet 14 for connecting to an oil inlet pipeline, and an oil outlet 15 for connecting to an oil outlet pipeline. The oil inlet 14 is located at the upper part of the motor, and the oil outlet 15 is located at the lower part of the motor to facilitate the flow of cooling oil.

[0076] After the oil cooling and heat dissipation structure is installed, it covers the inner surface of the stator core 2. The inner cylindrical surface of the oil cooling and heat dissipation structure is provided with an inner surface spiral protrusion 9, which forms a spiral air duct together with the outer surface of the rotor; the air gap space of the motor is small, and the minimum inner diameter of the two sides of the open end ring structure 6 is smaller than the minimum inner diameter of the part located in the middle of the motor air gap between the two end plate structures 7, that is, Figure 6 R1 is smaller than R2, thus ensuring that the cylindrical oil cooling structure does not interfere with the rotor after installation;

[0077] The open end ring structures 6 on both sides serve to receive the cooling oil. The thickness of the open end ring structures on both sides is large, ensuring that they are strong enough. The annular closed space 12 at the end is filled with cooling oil and can operate safely. At the same time, the oil cooling and heat dissipation structure can completely isolate the stator space and the rotor space of the motor without affecting each other.

[0078] When the motor is running, cooling oil flows from the oil inlet 14 into the annular enclosed spaces 12 on both sides, filling the annular enclosed spaces 12 and the intermediate pipe 8, and finally flows out from the oil outlet 15 at the bottom of the housing. The stator slot windings 5 ​​and the end windings 3 are completely immersed in the cooling oil. The heat generated by the windings is transferred and carried away by the flow of the cooling oil. The cooling oil directly cools the heat source, reducing the intermediate heat conduction link, lowering the thermal resistance, and significantly improving the heat dissipation effect.

[0079] As the motor loss changes, the flow rate of cooling oil can be adjusted. As the motor load increases, the winding current increases, and the winding part heats up seriously, increasing the cooling oil flow rate can effectively reduce the temperature rise of the stator winding. When the motor load decreases, reducing the cooling oil flow rate can not only ensure the cooling effect, but also save the amount of cooling oil, so that the cooling oil flow rate is matched with the heat load.

[0080] When the motor is running under load conditions, the motor rotor rotates at high speed, and the air flow on the rotor surface is disordered, which is not conducive to the heat dissipation of the rotor surface. At the same time, due to the influence of the opening of the stator slot 1 of the stator core 2, local air turbulence is formed at the slot opening, further increasing the wind friction loss on the rotor surface.

[0081] The oil-cooling and heat dissipation structure covers the inner surface of the stator core 2, covering the openings of the stator slots 1. A spiral wind pattern forms on the inner surface of the oil-cooling and heat dissipation structure. When the motor rotor rotates at high speed, air flowing into the air gap from one end of the motor flows along the spiral channel in the air gap to the other end. The spiral channel acts as a guide, ensuring unidirectional air flow and improving the air flow state within the air gap. After flowing out of the air gap, the air can exchange heat with the end rings, transferring the heat to the cooling oil in the end rings.

[0082] When the motor speed is low, the relative speed between the motor rotor and the spiral pipe is small, the axial air flow velocity is slow, and the friction between the air in the air gap and the rotor surface is small; when the motor speed increases, the relative speed between the motor rotor and the spiral pipe increases, the axial air flow velocity becomes larger, and the rotor surface loss increases; the air flow velocity and the rotor wind friction loss can be automatically matched to achieve the purpose of cooling the rotor surface.

[0083] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An oil cooling and heat dissipation structure, characterized in that: The stator core (2) of the motor to which the oil cooling and heat dissipation structure is applicable is a cylindrical structure, and a plurality of stator slots (1) are evenly distributed on the stator core (2), and the stator slots are open slots, which make the inner surface of the stator core a non-complete smooth cylindrical surface; Part of the winding is located in the stator slot (1), and part of the winding is exposed outside the two ends of the stator core (2); the winding exposed at the two ends of the stator core (2) is the end winding (3), a main insulating material (4) is provided in the stator slot (1), and the innermost part is the in-slot winding (5), and the in-slot winding (5) and the main insulating material (4) are both located inside the stator slot (1); The oil cooling and heat dissipation structure comprises: an open end ring structure (6), an end plate structure (7), and a cooling pipeline (8); The open end ring structure (6) is configured as a cylindrical body, and two annular end plate structures (7) are provided on the outer surface thereof and are parallel to each other and extend radially outward. The two end plate structures (7) are parallel to each other and are annular structures extending radially outward on the outer surface of the cylindrical body. The cooling pipeline (8) is a hollow structure, the number of the cooling pipelines (8) is consistent with the number of the stator slots (1), the pipeline shape of the cooling pipeline (8) is consistent with the open slot shape of the stator slot (1), and between the two end plate structures (7), multiple cooling pipelines (8) are connected together through the two end plate structures (7) to form a complete annular structure; Inside the open end ring structure (6), a spiral protrusion (9) is provided on the inner surface, and the protrusion is spirally wound along the axial direction of the inner surface; in the axial direction, the inner diameter of the open end ring structure (6) is divided into three parts; the part between the two end plate structures (7) is the middle part, and its inner diameter is defined as R2; the two parts on both sides of the middle part are defined as the end parts, and the inner diameters of the end parts are the same, and are defined as R1; it is set so that: R1 is smaller than R2; thereby, the cylinder thickness of the end parts of the open end ring structure (6) is greater than the cylinder thickness of the middle part; The open end ring structure (6), the end plate structure (7), the motor end cover (10) and the housing (11) form an annular closed space (12), the end winding (3) of the motor is completely located in the annular closed space (12), the annular closed spaces (12) on both sides of the motor form a connected space through the middle cooling pipeline (8), the in-slot winding (5) of the motor is located in the cooling pipeline (8), and the end winding (3) is located in the annular closed space (12), so that the motor winding is completely located in the annular closed space (12); The motor end cover (10) is provided with an oil inlet (14) for connecting to an oil inlet pipeline, and the motor end cover (10) is also provided with an oil outlet (15) for connecting to an oil outlet pipeline; wherein the oil inlet (14) is located at the upper part of the motor, and the oil outlet (15) is located at the lower part of the motor, so as to facilitate the flow of cooling oil.

2. The oil cooling and heat dissipation structure according to claim 1, characterized in that: The two end plate structures (7) are made of insulating material. The two end plate structures (7) can serve as insulating plates on both sides of the stator core (2) of the motor and can also serve as connections for connecting multiple cooling pipes (8).

3. The oil cooling and heat dissipation structure according to claim 1, wherein: The cooling pipeline (8) is made of insulating material, and the thickness of the pipeline is consistent with the thickness of the main insulating material (4) in the motor slot, and can be used as an insulating component in the stator slot (1).

4. The oil cooling and heat dissipation structure according to claim 1, wherein: The cooling pipeline (8) is structured to ensure that the stator slots (1) of the motor stator core (2) are filled.

5. The oil cooling and heat dissipation structure according to claim 1, wherein: After the oil cooling and heat dissipation structure is installed, it covers the inner surface of the stator core (2); the inner cylindrical surface of the oil cooling and heat dissipation structure is provided with the inner surface spiral protrusion (9), which forms a spiral air duct together with the outer surface of the rotor; The air gap space of the motor is relatively small, and the minimum inner diameter of the two end portions of the open end ring structure (6) is set to be smaller than the minimum inner diameter of the portion located in the motor air gap between the two middle end plate structures (7), thereby ensuring that the cylindrical oil cooling and heat dissipation structure does not interfere with the rotor after installation.

6. The oil cooling and heat dissipation structure according to claim 5, characterized in that: The open end ring structures (6) on both sides play the role of receiving cooling oil. The open end ring structures on both sides are thick to ensure that they are strong enough. The annular closed space (12) at the end is filled with cooling oil and can operate safely. At the same time, the oil cooling and heat dissipation structure can completely isolate the stator space and the rotor space of the motor without affecting each other.

7. The oil cooling and heat dissipation structure according to claim 6, characterized in that: When the motor is running, cooling oil flows from the oil inlet (14) into the annular sealed spaces (12) on both sides, fills the annular sealed spaces (12) and the cooling pipe (8) in the middle, and finally flows out from the oil outlet (15) at the bottom of the casing; the motor's slot windings (5) and end windings (3) are completely immersed in the cooling oil, and the heat generated by the windings is transferred and carried away by the flow of the cooling oil. The cooling oil directly cools the heat source, reducing the intermediate heat conduction link, lowering the thermal resistance, and greatly improving the heat dissipation effect.

8. The oil cooling and heat dissipation structure according to claim 7, characterized in that: As the motor loss changes, the flow rate of cooling oil can be adjusted. As the motor load increases, the winding current increases, and the winding part heats up seriously, increasing the cooling oil flow rate can effectively reduce the temperature rise of the stator winding. When the motor load decreases, reducing the cooling oil flow rate can not only ensure the cooling effect, but also save the amount of cooling oil, so that the cooling oil flow rate is matched with the heat load.

9. The oil cooling and heat dissipation structure according to claim 8, characterized in that: When the motor is running under load conditions, the motor rotor rotates at high speed, and the air flow state on the rotor surface is disordered, which is not conducive to heat dissipation on the rotor surface. At the same time, due to the influence of the stator slot (1) opening of the stator core (2), local air turbulence is formed at the slot opening, further increasing the wind friction loss on the rotor surface. The oil cooling and heat dissipation structure is covered on the inner surface of the stator core (2), and the opening of the stator slot (1) is covered. A spiral wind is formed on the inner surface of the oil cooling and heat dissipation structure. When the motor rotor rotates at high speed, the air flowing into the air gap at one end of the motor flows along the spiral pipeline channel of the air gap to the other side. The spiral channel plays a role in drainage, ensuring the unidirectionality of the air flow and improving the air flow state inside the air gap. After the air flows out of the air gap, it can realize heat exchange with the end ring and transfer the heat to the cooling oil of the end ring.

10. The oil cooling and heat dissipation structure according to claim 9, characterized in that: When the motor speed is low, the relative speed between the motor rotor and the spiral pipe is small, the axial air flow velocity is slow, and the friction between the air in the air gap and the rotor surface is small; when the motor speed increases, the relative speed between the motor rotor and the spiral pipe increases, the axial air flow velocity becomes larger, and the rotor surface loss increases; the air flow velocity and the rotor wind friction loss can be automatically matched to achieve the purpose of cooling the rotor surface.

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