Stator oil cooling structure

Abstract

The invention relates to a stator oil cooling structure. The stator oil cooling structure comprises a plurality of stacked first punching sheets, second punching sheets and third punching sheets, wherein the first punching sheets comprise first cooling holes and second cooling holes; the second type of punching sheets are stacked below the first type of punching sheets and comprise third type of cooling holes; the third type of punching sheets are stacked below the second type of punching sheets and comprise fourth type of cooling holes; wherein the first type of cooling holes and the second type of cooling holes form axial flow channels, the third type of cooling holes form radial flow channels, the third type of cooling holes are closed, the fourth type of cooling holes are small holes, cooling oil flows through the axial flow channels, the radial flow channels and the small holes, and the second type of cooling holes can also position the first type of punching sheets. A radial flow channel of the third cooling hole is designed to be closed, so that cooling oil is prevented from partially flowing out of the iron core, and the cooling efficiency is improved; and the height of the radial flow channel of the third cooling hole is designed to be the same as the width of the axial flow channel of the first cooling hole.

Description

Technical Field

[0001] The invention relates to the technical field of stator cores, and in particular to a stator oil cooling structure. Background Art

[0002] The stator core is one of the important parts of the motor. It is the main part of the motor magnetic circuit and is usually made of 0.35-0.5 mm thick silicon steel sheets laminated to reduce eddy current and hysteresis losses. Silicon steel sheets are a material with excellent magnetic conductivity and low loss characteristics, and are widely used in the manufacture of iron cores for motors and transformers.

[0003] The stator core and the rotor core together form the magnetic circuit of the motor and are the key part of the motor's energy conversion. The stator core is usually wound with stator windings, which are the main part of the motor circuit. The stator core provides support and protection for the windings. During the operation of the motor, the stator core will heat up. Through reasonable heat dissipation design, such as opening heat dissipation slots or using oil cooling, the heat can be effectively dissipated to ensure the stable operation of the motor.

[0004] The stator core is usually made of multiple silicon steel sheets stacked together to form an integral structure. These silicon steel sheets are separated by an insulating layer to reduce eddy current losses. The inner circle of the stator core is slotted for embedding the stator winding. The shape and number of the slots are determined according to the design requirements of the motor. The required shape and size are punched out on the silicon steel sheets using a die. The punched silicon steel sheets are stacked together in a certain order and manner to form an integral structure. The stacking pressure and stacking accuracy need to be controlled during the stacking process to ensure the quality and performance of the stator core. Insulating varnish or insulating paper is applied to the stacked stator core to improve its insulation performance. The stator winding is embedded in the slots of the stator core and fixed and connected. The manufactured stator core is subjected to quality inspection and performance testing to ensure that it meets the design requirements.

[0005] During the operation of the motor, the stator core may be affected by factors such as vibration, wear and corrosion. Therefore, the stator core needs to be inspected and maintained regularly. Maintenance includes cleaning the dirt and dust on the surface of the stator core, checking the integrity of the insulation layer, repairing or replacing damaged parts, etc.

[0006] With the continuous development of motor technology, the stator core is also constantly innovating and improving. For example, the use of higher-quality silicon steel sheet materials, optimization of lamination process and heat dissipation design, and development of new insulation materials can further improve the performance and reliability of the stator core. At the same time, with the rapid development of new energy vehicles, intelligent manufacturing and other fields, the stator core will also usher in a broader application prospect. The stator core is an important part of the motor, with functions such as forming a magnetic circuit, supporting windings and heat dissipation. Through reasonable manufacturing processes and maintenance measures, the quality and performance of the stator core can be ensured, providing a strong guarantee for the stable operation of the motor.

[0007] The stator core is one of the main components of the motor, and its cooling has an important impact on the life and efficiency of the motor. Cooling methods include air cooling, water cooling, hydrogen cooling, oil cooling, etc.

[0008] Air cooling uses air to flow through the surface of the stator core to achieve cooling. The advantages are simplicity, safety, and low operating cost. The disadvantages are that the cooling effect is affected by the environment and it is difficult to accurately control the temperature. The application scenario is suitable for motors with lower power and motors in some specific environments.

[0009] Water cooling is to use water to remove the heat inside the stator core to achieve cooling. The advantage is that it is more advantageous for special situations such as high power, high temperature, and high frequency. The disadvantage is that the design, installation, operation and maintenance costs are high. The application scenario is suitable for high-power motors.

[0010] Hydrogen cooling uses the characteristics of hydrogen's low specific gravity and high thermal conductivity to achieve cooling by sucking and pressurizing it with a fan, so that hydrogen circulates between the dynamic and static gaps of the generator. The advantage is that the cooling efficiency is high and the temperature of the stator core can be effectively reduced. The application scenario is mainly used for cooling the stator core and rotor of the generator.

[0011] Oil cooling is a new cooling method. For example, Beijing Hainachuan Auto Parts Co., Ltd. has obtained a patent for "cooling structure and motor", which cools the stator core through the oil flow in the oil guide ring and cooling channel. The advantages are high cooling efficiency and good heat dissipation effect. The application scenario is suitable for motors that require efficient cooling.

[0012] Stator core oil cooling is a motor cooling technology that is mainly used to reduce the heat generated by the motor during operation and ensure the stable operation of the motor. The following is a detailed explanation of stator core oil cooling:

[0013] Stator core oil cooling technology is to set up cooling oil channels around the stator core of the motor, and use the circulating flow of cooling oil to take away the heat generated by the stator core, thereby reducing the temperature of the motor. This cooling method utilizes the heat dissipation performance of oil, which can effectively transfer the heat inside the motor to the outside and maintain the normal working temperature of the motor. The stator core is usually made of silicon steel sheets or amorphous alloy materials, with good magnetic conductivity and mechanical strength. Annular grooves or circumferential oil cooling grooves can be opened on the outer side and circumference of the axial middle part of the stator core so that cooling oil can flow in and take away heat. Oil inlets and outlets can be set on both sides of the stator core, and the cooling oil circulates inside the stator core through these channels. In order to enhance the heat exchange effect, each adjacent lamination group can be slightly offset so that the cooling oil can contact more area during the flow process. The oil pump is responsible for delivering the cooling oil to the cooling channel of the stator core, while the radiator is used to dissipate the heat in the cooling oil to the external environment. The radiator is usually installed on the top or side of the motor, and the heat dissipation effect is improved by a fan or other heat-conducting medium.

[0014] In the current stator core oil cooling solution, the stator core is poorly cooled under traditional technology. The oil guide pipe currently used is sprayed to cool the winding end, but it is easy to have uneven cooling, which affects its cooling effect. Therefore, it is proposed to make a channel inside the core for cooling. How to improve the oil cooling technology of the stator core and find an effective cooling solution is a problem to be solved.

[0015] With the development of stator core technology, stator core oil cooling technology has emerged. The oil guide pipe is sprayed to cool the winding end, but uneven cooling is prone to occur, affecting its cooling effect.

[0016] In traditional technology, channels are made inside the iron core for cooling.

[0017] However, the current stator core oil cooling structure cannot restrict the flow direction of the oil in the radial flow channel of the stator core. Summary of the invention

[0018] Based on this, a stator oil cooling structure is provided, wherein the radial flow channel of the third cooling hole is designed to be closed to prevent the cooling oil from partially flowing to the outside of the core, thereby improving the cooling efficiency; the height of the radial flow channel of the third cooling hole is designed to be the same as the width of the axial flow channel of the first cooling hole; it is used to reduce the pressure caused by the sudden change in the flow direction of the cooling oil and reduce its kinetic energy loss; the fourth cooling hole is designed to be located near the winding outlet to increase the area it sprays to achieve a better cooling effect; the stator core is composed of three punchings, namely, the first punching, the second punching and the third punching. The cooling oil flowing through the stator core is guided through the axial flow channel of the first cooling hole and the second cooling hole → the radial flow channel of the third cooling hole → the fourth cooling hole, and then converges to the fourth cooling hole on the stator core near the winding and sprays out. The cooling oil is sprayed on the winding end from the fourth cooling hole, which is evenly distributed and surrounds the winding, to achieve cooling of the winding end and improve the cooling efficiency.

[0019] A stator oil cooling structure, the stator oil cooling structure comprising:

[0020] A plurality of stacked first punching sheets, the first punching sheets comprising first cooling holes and second cooling holes;

[0021] A plurality of stacked second punching sheets, which are stacked below the first punching sheets, and the second punching sheets include third cooling holes;

[0022] A plurality of stacked third punching sheets, which are stacked below the second punching sheets, wherein the third punching sheets include fourth cooling holes;

[0023] Among them, the first cooling hole and the second cooling hole form an axial flow channel, the third cooling hole forms a radial flow channel, the third cooling hole is closed, and the fourth cooling hole is a small hole. The cooling oil flows through the axial flow, radial flow channel and small hole, and the second cooling hole can also position the first punching plate.

[0024] In one embodiment, the stacking height of the first type of punching sheets is greater than the height of the second type of punching sheets, and the stacking height of the first type of punching sheets is greater than the height of the third type of punching sheets.

[0025] In one embodiment, the first cooling holes and the second cooling holes are arranged on the outside of the first punching sheet.

[0026] In one embodiment, the fourth type of cooling hole is arranged at a position close to the stator slot, and the fourth type of cooling hole is arranged between two stator slots.

[0027] In one embodiment, the first cooling hole is rectangular.

[0028] In one embodiment, the stacking thickness of the second type of punching sheets is equal to the width of the first type of cooling holes.

[0029] In one embodiment, the stacking thickness of the third type of punching sheets is consistent with the stacking thickness of the second type of punching sheets.

[0030] In one embodiment, the fourth type of cooling hole is located directly below the radial channel of the third type of cooling hole close to one end of the winding.

[0031] In one of the embodiments, the fourth type of cooling holes are provided at the winding ends.

[0032] In one of the embodiments, an oil ring is arranged on the top of the first punching plate.

[0033] In the above-mentioned stator oil cooling structure, the radial flow channel of the third cooling hole is designed to be closed to prevent the cooling oil from partially flowing to the outside of the core, thereby improving the cooling efficiency; the height of the radial flow channel of the third cooling hole is designed to be the same as the width of the axial flow channel of the first cooling hole; it is used to reduce the pressure caused by the sudden change in the flow direction of the cooling oil and reduce its kinetic energy loss; the fourth cooling hole is designed to be close to the winding outlet to increase the area it sprays to achieve a better cooling effect; the stator core is composed of three punchings, namely the first punching, the second punching and the third punching. The cooling oil flowing through the stator core is guided through the axial flow channel of the first cooling hole and the second cooling hole → the radial flow channel of the third cooling hole → the fourth cooling hole, and then converges to the fourth cooling hole on the stator core near the winding and sprays out. The cooling oil is sprayed on the winding end from the fourth cooling hole, which is evenly distributed and surrounds the winding, to achieve cooling of the winding end and improve the cooling efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Fig. 1 is a schematic structural diagram of the present invention;

[0035] FIG2 is a schematic diagram of a first punching sheet of the present invention;

[0036] FIG3 is a schematic diagram of a second punching sheet of the present invention;

[0037] FIG. 4 is a schematic diagram of a third punching sheet of the present invention.

[0038] Among them, 1. the first type of cooling hole; 2. the second type of cooling hole; 3. the third type of cooling hole; 4. the fourth type of cooling hole; 11. the first type of punching sheet; 12. the second type of punching sheet; 13. the third type of punching sheet. DETAILED DESCRIPTION

[0039] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0040] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0041] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0042] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0043] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0044] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0045] As shown in FIG. 1 , the present invention provides a stator oil cooling structure, including a first type of punching sheet 11 , a second type of punching sheet 12 and a third type of punching sheet 13 .

[0046] A plurality of first punching sheets 11 are stacked, and first cooling holes 1 and second cooling holes 2 are provided on the first punching sheets 11. After the first punching sheets 11 are stacked, the first cooling holes 1 and the second cooling holes 2 can form an axial channel, and the second cooling holes 2 also have the function of positioning the first punching sheets 11.

[0047] After the cooling oil enters the axial channel formed by the first cooling hole 1 and the second cooling hole 2 from the oil ring, the stator can be cooled in the axial direction. The first cooling hole 1 and the second cooling hole 2 are arranged on the outside of the first punching sheet 11, and the channel formed by the first cooling hole 1 and the second cooling hole 2 is located near the outer surface of the stator core, so that the influence of the first cooling hole 1 and the second cooling hole 2 on the magnetic flux of the stator core is reduced.

[0048] In one embodiment, the number of stacked first-type punching sheets 11 is relatively large.

[0049] A plurality of second punches 12 are stacked under the first punch 11. The second punches 12 are provided with third cooling holes 3. After the second punches 12 are stacked, the third cooling holes 3 form radial channels. After the cooling oil flows out from the axial channels of the first cooling holes 1 and the second cooling holes 2, it directly enters the radial channels of the third cooling holes 3.

[0050] In one embodiment, the radial channel of the third type of cooling hole 3 is closed, and the cooling oil flows from the outside to the inside of the stator core to achieve the effect of cooling and drainage.

[0051] In one embodiment, the stacking quantity of the second type of punching sheets 12 is less than the stacking quantity of the first type of punching sheets 11 .

[0052] The third punching sheet 13 is stacked below the second punching sheet 12. The third punching sheet 13 is located near the stator slot, and a fourth cooling hole 4 is opened between two stator slots. The fourth cooling hole 4 is located directly below the radial channel of the third cooling hole 3 near one end of the winding. The cooling oil flows from the outside to the inside along the radial channel of the third cooling hole 3, and is ejected from the fourth cooling hole 4 due to pressure. Since the fourth cooling hole 4 is set close to the end of the winding, the ejected cooling oil is directly sprayed on the end of the winding, and the winding is evenly cooled.

[0053] In one embodiment, the first type of punching sheet 11 occupies most of the height, and the second type of punching sheet 12 and the third type of punching sheet 13 each occupy a small portion of the height.

[0054] In one embodiment, the first cooling hole 1 is rectangular.

[0055] In one embodiment, the stacking thickness of the second punching plate 12 is equal to the width of the first cooling hole 1 , so as to reduce the kinetic energy loss when the liquid suddenly changes direction and reduce the pressure on the second punching plate 12 .

[0056] In one embodiment, the stacking thickness of the third type of punching sheets 13 is consistent with the stacking thickness of the second type of punching sheets 12 , so that the flow direction of the cooling oil can be controlled while ensuring the stator performance.

[0057] In one embodiment, the fourth type of cooling holes 4 are small holes.

[0058] In one embodiment, the overall shapes of the first punch 11, the second punch 12 and the third punch 13 are not significantly changed, the opening shapes of the first cooling hole 1 and the second cooling hole 2 of the first punch 11 are simple and uniform, the opening shape of the third cooling hole 3 of the second punch 12 is also simple and uniform, and the opening shape of the fourth cooling hole 4 of the third punch 13 is also simple and uniform, which has little impact on the molds of the first punch 11, the second punch 12 and the third punch 13, and the process is simple and easy to implement.

[0059] The present invention designs an axial channel, a radial channel and a small hole inside the stator core, so that the cooling oil can be used more effectively.

[0060] The first cooling hole 1 and the second cooling hole 2 are made by drilling holes on the stator core close to the outer diameter, and the hole sizes are appropriate, which can reduce the influence on the magnetic flux of the stator core.

[0061] The third type of cooling hole 3 adopts a closed radial flow channel to limit the flow direction of the cooling oil and improve the cooling efficiency.

[0062] The stator core is composed of three types of punchings, namely, the first punching 11, the second punching 12 and the third punching 13. The cooling oil flowing through the stator core is guided through the axial flow channel of the first cooling hole 1 and the second cooling hole 2 → the radial flow channel of the third cooling hole 3 → the fourth cooling hole 4, and then converges to the fourth cooling hole 4 near the winding on the stator core and sprays out. The cooling oil is sprayed on the end of the winding from the fourth cooling hole 4, which is evenly distributed and surrounds the winding, to achieve cooling of the end of the winding, and improve the cooling efficiency.

[0063] The preparation process of the first punching sheet 11, the second punching sheet 12, the third punching sheet 13 and the iron core is the same as that of the ordinary iron core. An oil ring is arranged on the top of the first punching sheet 11, that is, an oil ring is arranged at one end of the starting point of the axial flow channel of the first cooling hole 1 and the second cooling hole 2, so that the cooling oil can smoothly enter the axial flow channel of the first cooling hole 1 and the second cooling hole 2.

[0064] The radial flow channel of the third type of cooling hole 3 is designed to be closed to prevent the cooling oil from partially flowing to the outside of the core, thereby improving the cooling efficiency.

[0065] The axial flow channels of the first cooling hole 1 and the second cooling hole 2 are relatively flat, and the height of the radial flow channel of the third cooling hole 3 is designed to be the same as the width of the axial flow channel of the first cooling hole 1. It is used to reduce the pressure caused by the sudden change of the flow direction of the cooling oil and reduce its kinetic energy loss. It can also flow smoothly in the radial flow channel of the third cooling hole 3 and spray out from the fourth cooling hole 4 at the end.

[0066] The fourth type of cooling hole 4 is designed to be located close to the winding outlet to increase the area sprayed, thereby achieving a better cooling effect.

[0067] As shown in FIG1 , the stator core is composed of three types of punchings, namely, the first punching 11, the second punching 12 and the third punching 13. The cooling oil flowing through the stator core is guided through the axial flow channel of the first cooling hole 1 and the second cooling hole 2 → the radial flow channel of the third cooling hole 3 → the fourth cooling hole 4, and then converges to the fourth cooling hole 4 near the winding on the stator core and sprays out. The cooling oil is sprayed on the end of the winding from the fourth cooling hole 4, which is evenly distributed and surrounds the winding, to achieve cooling of the end of the winding, and improve the cooling efficiency.

[0068] The stacking number of the first type of punching plate 11 is the largest, while the stacking number of the second type of punching plate 12 and the third type of punching plate 13 is relatively small. The stacking thickness of the second type of punching plate 12 is equal to the width of the first type of cooling hole 1, which is used to reduce the kinetic energy loss when the liquid suddenly changes direction, and at the same time reduce the pressure on the second type of punching plate 12. The stacking thickness of the third type of punching plate 13 is consistent with the stacking thickness of the second type of punching plate 12, which can control the flow direction of the cooling oil while ensuring the stator performance.

[0069] As shown in Figure 2, the first cooling hole 1 and the second cooling hole 2 are arranged on the outside of the first punching sheet 11, and the channel formed by the first cooling hole 1 and the second cooling hole 2 is located near the outer surface of the stator core. The axial flow channel shape of the first cooling hole 1 and the second cooling hole 2 is relatively flat, so that the influence of the first cooling hole 1 and the second cooling hole 2 on the magnetic flux of the stator core is reduced.

[0070] As shown in FIG3 , the second punching sheet 12 is provided with the third cooling hole 3. After the second punching sheets 12 are stacked, the third cooling hole 3 forms a radial channel. After the cooling oil flows out of the axial channels of the first cooling hole 1 and the second cooling hole 2, it directly enters the radial channel of the third cooling hole 3. The radial channel of the third cooling hole 3 is closed, and the cooling oil flows from the outside to the inside of the stator core, achieving the effect of cooling and drainage.

[0071] As shown in FIG4 , the third punching sheet 13 is located near the stator slot, and a fourth cooling hole 4 is provided between two stator slots. The fourth cooling hole 4 is located directly below the radial channel of the third cooling hole 3 near one end of the winding. The cooling oil flows from the outside to the inside along the radial channel of the third cooling hole 3, and is ejected from the fourth cooling hole 4 due to pressure. Since the fourth cooling hole 4 is arranged close to the end of the winding, the ejected cooling oil is directly sprayed on the end of the winding, and the winding is evenly cooled.

[0072] The stator core is composed of three types of punchings, namely, the first punching 11, the second punching 12 and the third punching 13. The cooling oil flowing through the stator core is guided through the axial flow channel of the first cooling hole 1 and the second cooling hole 2 → the radial flow channel of the third cooling hole 3 → the fourth cooling hole 4, and then converges to the fourth cooling hole 4 near the winding on the stator core and sprays out. The cooling oil is sprayed on the end of the winding from the fourth cooling hole 4, which is evenly distributed and surrounds the winding, to achieve cooling of the end of the winding, and improve the cooling efficiency.

[0073] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0074] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A stator oil cooling structure, characterized in that: The stator oil cooling structure comprises: A plurality of stacked first punching sheets (11), the first punching sheets (11) comprising a first cooling hole (1) and a second cooling hole (2); A plurality of stacked second punching sheets (12) stacked below the first punching sheets (11), the second punching sheets (12) comprising third cooling holes (3); A plurality of stacked third punching sheets (13) stacked below the second punching sheets (12), the third punching sheets (13) comprising fourth cooling holes (4); The first cooling hole (1) and the second cooling hole (2) form an axial flow channel, the third cooling hole (3) forms a radial flow channel, the third cooling hole (3) is closed, the fourth cooling hole (4) is a small hole, the cooling oil flows through the axial flow, radial flow channel and small hole, and the second cooling hole (2) can also position the first punching plate (11).

2. The stator oil cooling structure according to claim 1, characterized in that: The stacking height of the first type of punching sheets (11) is greater than the height of the second type of punching sheets (12), and the stacking height of the first type of punching sheets (11) is greater than the height of the third type of punching sheets (13).

3. The stator oil cooling structure according to claim 1, characterized in that: The first type of cooling hole (1) and the second type of cooling hole (2) are arranged on the outside of the first type of punching sheet (11).

4. The stator oil cooling structure according to claim 3 is characterized in that: The fourth type of cooling hole (4) is arranged at a position close to the stator slot, and the fourth type of cooling hole (4) is arranged between two stator slots.

5. The stator oil cooling structure according to claim 4, characterized in that: The first cooling hole (1) is rectangular.

6. The stator oil cooling structure according to claim 1, characterized in that: The stacking thickness of the second punching sheets (12) is equal to the width of the first cooling holes (1).

7. The stator oil cooling structure according to claim 6, characterized in that: The stacking thickness of the third punching sheet (13) is consistent with the stacking thickness of the second punching sheet (12).

8. The stator oil cooling structure according to claim 4, characterized in that: The fourth type of cooling hole (4) is located directly below the radial channel of the third type of cooling hole (3) close to one end of the winding.

9. The stator oil cooling structure according to claim 1, characterized in that: The fourth type of cooling hole (4) is arranged at the winding end.

10. The stator oil cooling structure according to claim 1, characterized in that: An oil ring is arranged on the top of the first punching plate (11).

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