Oil cooling structure in slot of flat wire motor stator

Abstract

This invention relates to the field of motor cooling technology and discloses an in-slot oil cooling structure for a flat wire motor. The structure includes a stator core, multiple flat wire windings, and an oil supply assembly. Multiple stator slots are formed along the circumferential direction of the stator core and extend axially through the core. The multiple flat wire windings are respectively disposed within the stator slots. The oil supply assembly is connected to the stator slots and supplies cooling oil to them. The flat wire windings are located within the stator slots, and the oil supply assembly supplies cooling oil to them, allowing the oil to directly contact and cool the windings. By supplying cooling oil to the stator slots through the oil supply assembly, the oil directly contacts the flat wire windings for heat exchange. This significantly shortens the heat conduction path and reduces thermal resistance, thereby significantly reducing the operating temperature of the flat wire windings under the same operating conditions, improving the motor's heat dissipation efficiency and continuous output capability.

Description

Technical Field

[0001] This invention belongs to the field of motor cooling technology, specifically relating to an oil cooling structure in the stator slot of a flat wire motor. Background Technology

[0002] As new energy vehicle motors develop towards higher power density, heat dissipation becomes increasingly prominent. Traditional air cooling and water cooling of the casing are no longer sufficient to meet the demands, and oil cooling technology has become mainstream due to its high heat exchange efficiency. Currently, there are three main types of oil cooling solutions for flat wire motors: one is to install axial oil channels in the stator yoke; the second is to install axial oil channels in the stator teeth; and the third is to install a spray structure at the winding ends. Solution 1 increases the outer diameter of the core due to the opening in the yoke, increasing the motor weight and reducing the power density. Furthermore, the oil channels are far from the straight sections of the winding within the slots, resulting in high thermal resistance and poor cooling effect. Solution 2, although the oil channels are closer to the windings, the openings in the teeth encroach on the magnetic conductive area, leading to increased magnetic flux density in the teeth and reduced slot area, affecting electromagnetic performance and NVH (noise, vibration, and harshness) performance. Solution 3 only sprays at the ends, leaving almost no cooling for the straight sections within the slots, causing the winding temperature to rise and limiting the motor's continuous output capability. The common drawback of the above solutions is that they all fail to allow the cooling medium to directly reach the core heat-generating area within the slots, resulting in poor heat dissipation in the straight sections of the windings. Summary of the Invention

[0003] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, embodiments of this invention propose an oil cooling structure within the stator slots of a flat wire motor. This device enables the cooling oil to directly contact the windings, thereby improving heat dissipation.

[0004] The flat wire motor stator slot oil cooling structure of this invention includes a stator core, multiple flat wire windings, and an oil supply assembly. Multiple stator slots are formed along the circumferential direction on the stator core, and these slots extend axially through the stator core. The multiple flat wire windings are respectively disposed in the multiple stator slots. The oil supply assembly is connected to the stator slots and is used to supply cooling oil to the stator slots. The flat wire windings are located in the stator slots, and the oil supply assembly supplies cooling oil to the stator slots. The cooling oil is in direct contact with the flat wire windings to cool them.

[0005] The stator slot oil cooling structure for a flat wire motor provided by this invention supplies cooling oil to the stator slots via an oil supply assembly, allowing the cooling oil to directly contact the flat wire windings for heat exchange after entering the stator slots. Compared to existing technologies where the cooling oil only flows through the oil channels in the core yoke or teeth, relies on indirect heat conduction through the core, or is only sprayed at the ends, this invention directly introduces the cooling medium into the stator slots to contact the heat source, significantly shortening the heat conduction path and reducing thermal resistance. This results in a significant reduction in the operating temperature of the flat wire windings under the same operating conditions, improving the motor's heat dissipation efficiency and continuous output capability. Furthermore, this structure eliminates the need for additional oil holes in the core yoke or teeth, avoiding encroachment on the effective magnetic conductive area of ​​the stator core, thus balancing the motor's electromagnetic and heat dissipation performance.

[0006] In some embodiments, there are two stator cores, and the oil supply assembly is located between the two stator cores. The oil supply assembly includes a circumferential oil groove core and a flow guide core. The outer diameter of the circumferential oil groove core is smaller than the outer diameter of the stator cores to form a circumferential oil groove on the outer periphery of the circumferential oil groove core. A connecting groove is formed in the circumferential oil groove core, and the connecting groove communicates with the adjacent stator slot. The flow guide core is disposed on one axial side of the circumferential oil groove core, and a flow guide hole is formed on the flow guide core. One end of the flow guide hole communicates with the circumferential oil groove, and the other end of the flow guide hole communicates with the adjacent stator slot and the connecting groove.

[0007] In some embodiments, the circumferential oil groove core is provided with a plurality of connecting slots evenly distributed along the circumferential direction, and the plurality of connecting slots correspond one-to-one with the plurality of stator slots.

[0008] In some embodiments, a plurality of flow guide holes are uniformly formed on the flow guide core along the circumferential direction, and the plurality of flow guide holes correspond one-to-one with a plurality of stator slots and a plurality of connecting slots.

[0009] In some embodiments, the flow guide hole extends radially inward from the outer peripheral surface of the flow guide core to the bottom of the stator slot.

[0010] In some embodiments, the flat wire winding passes through the stator slot, the connecting slot, and the guide hole, and the flat wire winding is arranged in multiple layers radially within the stator slot.

[0011] In some embodiments, an in-slot axial oil passage is formed between two adjacent layers of flat wire windings. The in-slot axial oil passage is disposed on the sidewall of the stator slot and extends along the axial direction of the stator core. The cooling oil flows in the in-slot axial oil passage and contacts the surface of the straight section of the flat wire winding.

[0012] This invention provides an axial oil passage within the stator slot between adjacent layers of flat wire windings, allowing cooling oil to directly enter the stator slot and directly contact the surface of the straight winding section for heat exchange. Compared to existing technologies where cooling oil only flows through the oil passages in the core yoke or teeth and relies on the core for indirect heat conduction, this invention shortens the heat conduction path to almost zero, significantly reducing thermal resistance. This results in a substantial reduction in the operating temperature of the straight winding section under the same operating conditions, preventing the formation of localized hot spots and improving the motor's continuous output capability.

[0013] In some embodiments, the cross-sectional shape of the axial oil passage in the groove is one or more combinations of rectangle, semicircle, triangle or trapezoid.

[0014] In some embodiments, the number of axial oil passages in the slot is equal to the number of layers of flat wire windings in the stator slot, and each axial oil passage in the slot is located between two adjacent layers of flat wire windings.

[0015] In some embodiments, the axial oil passage in the groove extends along the axial direction of the stator core, and both ends of the axial oil passage in the groove extend to the two end faces of the stator core, respectively.

[0016] In this invention, the axial oil channel inside the slot runs through the stator core along its axis. After directly cooling the straight section of the winding, the cooling oil flows out from both ends of the core and sprays onto the winding ends for auxiliary cooling. This design allows the cooling oil to complete two-stage cooling of the straight section and the ends in a single flow, fully covering the main heat-generating areas of the flat wire winding, resulting in higher cooling efficiency and a more compact system structure. Attached Figure Description

[0017] Figure 1 This is an overall schematic diagram of the present invention.

[0018] Figure 2 This is a schematic diagram of the explosion state of the present invention.

[0019] Figure 3 This is a schematic diagram of the stator core structure in this invention.

[0020] Figure 4 This is a schematic diagram of the circumferential oil groove core in this invention.

[0021] Figure 5 This is a schematic diagram of the flow-guiding core in this invention.

[0022] Figure 6 This is a schematic diagram of the internal structure of the present invention.

[0023] Figure 7 This is a schematic diagram of the assembly state of the present invention. Figure 1 .

[0024] Figure 8This is a schematic diagram of the assembly state of the present invention. Figure 2 .

[0025] Figure 9 This is the present invention. Figure 7 A magnified view of a portion of point A in the middle.

[0026] Figure label:

[0027] 1. Stator core; 11. Stator slot; 12. Axial oil passage within the slot; 2. Flat wire winding; 3. Oil supply assembly; 31. Circumferential oil groove core; 311. Circumferential oil groove; 312. Connecting groove; 32. Flow guide core; 321. Flow guide hole. Detailed Implementation

[0028] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0029] like Figures 1-9 As shown, the oil cooling structure in the stator slot of the flat wire motor according to this embodiment of the invention includes a stator core 1, flat wire windings 2, and an oil supply assembly 3. The stator core 1 serves as the main magnetic structure of the motor stator, and multiple stator slots 11 are uniformly formed along the circumferential direction on its inner circumferential surface. Each stator slot 11 extends axially from one end face of the stator core 1 to the other end face. Multiple flat wire windings 2 are respectively embedded in their corresponding stator slots 11. The oil supply assembly 3 is connected to the stator slots 11 and is used to introduce cooling oil from an external oil passage and distribute it to each stator slot 11. When the cooling oil enters the stator slots 11, it can directly contact the outer surface of the straight section of the flat wire winding 2 and undergo forced convection heat transfer, thereby quickly removing the heat generated by the flat wire winding 2 and achieving efficient cooling of the winding.

[0030] The stator slot oil cooling structure for a flat wire motor provided by this invention supplies cooling oil to the stator slots via an oil supply assembly, allowing the cooling oil to directly contact the flat wire windings for heat exchange after entering the stator slots. Compared to existing technologies where the cooling oil only flows through the oil channels in the core yoke or teeth, relies on indirect heat conduction through the core, or is only sprayed at the ends, this invention directly introduces the cooling medium into the stator slots to contact the heat source, significantly shortening the heat conduction path and reducing thermal resistance. This results in a significant reduction in the operating temperature of the flat wire windings under the same operating conditions, improving the motor's heat dissipation efficiency and continuous output capability. Furthermore, this structure eliminates the need for additional oil holes in the core yoke or teeth, avoiding encroachment on the effective magnetic conductive area of ​​the stator core, thus balancing the motor's electromagnetic and heat dissipation performance.

[0031] In some embodiments of the present invention, there are two stator cores 1, which are arranged axially spaced apart, and the oil supply assembly 3 is sandwiched between the two stator cores 1 in the axial direction.

[0032] In some embodiments of the present invention, the oil supply assembly 3 further includes a circumferential oil groove core 31 and a guide core 32. The outer diameter of the circumferential oil groove core 31 is smaller than that of the stator core 1. When the stator assembly containing this cooling structure is press-fitted into the cylindrical motor housing, a radial gap exists between the outer circumferential surface of the circumferential oil groove core 31 and the inner wall of the motor housing. This gap naturally forms an annular cavity around the stator axis, namely the circumferential oil groove 311. The circumferential oil groove 311 is used to receive cooling oil introduced from the oil inlet of the motor housing, and its annular continuous structure allows the cooling oil to spread rapidly and evenly along the circumferential direction, ensuring that the oil inlet pressure of each stator groove 11 is balanced. Meanwhile, the circumferential oil groove core 31 is also provided with multiple connecting slots 312. The connecting slots 312 penetrate the circumferential oil groove core 31 along the axial direction, and the position of each connecting slot 312 is aligned with the position of the stator slot 11 on the adjacent stator core 1 along the axial direction, so that the stator slot 11 can maintain axial continuity through the connecting slots 312, so that the flat wire winding 2 can pass through continuously.

[0033] This invention utilizes a circumferential oil groove core segment with a reduced outer diameter, which, together with the motor housing, defines the circumferential oil groove. Cooling oil is introduced into the stator slots through guide holes on the guide core segment. Both the circumferential oil groove core segment and the guide core segment are integrated into the axial segmented structure of the stator core, eliminating the need for complex oil injection pipes or oil ring components on the motor housing or end cover. The overall structure is compact, which helps improve the power density and space utilization of the motor.

[0034] In some embodiments of the present invention, the flow guiding core 32 is disposed on one axial side of the circumferential oil groove core 31. Each flow guiding core 32 is provided with a flow guiding hole 321, which extends radially along the flow guiding core 32. Specifically, one end of the flow guiding hole 321 opens onto the outer circumferential surface of the flow guiding core 32, thereby maintaining communication with the circumferential oil groove 311; the other end of the flow guiding hole 321 extends radially inward until it communicates with the stator groove 11 on the stator core 1 and the communicating groove 312 on the circumferential oil groove core 31. Thus, the flow guiding hole 321 constitutes a radial oil guiding channel connecting the outer annular circumferential oil groove 311 and the inner stator groove 11.

[0035] In some embodiments of the present invention, to ensure the uniformity of cooling oil distribution, a plurality of connecting grooves 312 on the circumferential oil groove core 31 are evenly distributed along the circumferential direction, and their number is equal to the number of stator grooves 11, with each connecting groove 312 axially aligned with one stator groove 11. Similarly, a plurality of guide holes 321 on the guide core 32 are evenly distributed along the circumferential direction, and the number of guide holes 321 is equal to the number of stator grooves 11 and connecting grooves 312, thus forming a one-to-one oil guiding relationship. In the radial direction, the guide holes 321 start from the outer circumferential surface of the guide core 32, extend radially inward, and terminate at the bottom region of the stator groove 11. When cooling oil flows from the circumferential oil groove 311 into the guide holes 321, it can be guided to the root of the stator groove 11 during radial flow, and then enter the interior of the stator groove 11. Afterward, the cooling oil flows along the stator groove 11... Figure 6 The arrows in the diagram indicate that the flow is directed towards the ends of the two stator cores 1.

[0036] In some embodiments of the present invention, the flat wire winding 2 serves as the main heat-generating component, continuously passing through the space defined by the stator slot 11, the connecting slot 312, and the guide hole 321 along the axial direction. Since the stator slot 11 is axially continuous, and the inner cavities of the connecting slot 312 and the guide hole 321 are connected to the slot cavity of the stator slot 11, the flat wire winding 2 can pass through the entire stator core 1 and the oil supply assembly 3 without obstruction. Inside each stator slot 11, the flat wire winding 2 is not arranged in a single layer, but rather in multiple orderly layers along the depth direction (i.e., radial direction) of the stator slot 11, such as the common four-layer, six-layer, or eight-layer flat wire structure. This multi-layer arrangement is beneficial for increasing the slot fill factor, but it also makes heat dissipation of the winding located deep within the slot more difficult, which is one of the core problems that the present invention aims to solve.

[0037] In some embodiments of the present invention, the axial oil channels 12 within the slots are located within the space defined by the sidewalls of the stator slots 11 and extend continuously along the axial direction of the stator core 1. When cooling oil enters the bottom region of the stator slots 11 through the guide holes 321, it rapidly fills these axial oil channels 12 and flows axially towards both ends of the stator core 1 under the drive of the oil supply pressure. During this flow, the cooling oil directly contacts the surface of the straight section of the flat wire winding 2 (including the exposed wide and narrow surfaces of the flat wire conductor), efficiently removing the heat generated by the winding copper loss through a single-phase forced convection heat transfer mechanism. Due to the extremely short heat conduction path and almost zero-distance contact, the thermal resistance of this structure is much lower than that of traditional cooling schemes relying on core conduction, significantly suppressing the temperature rise of the straight section of the winding within the slots.

[0038] In some embodiments of the present invention, the cross-sectional shape of the axial oil passage 12 within the groove can be flexibly selected according to specific requirements. For example, the cross-sectional shape can be any one of a rectangle, a semi-circle, a triangle, or a trapezoid, or multiple combinations of the above shapes can be used in the same embodiment. The cross-sectional dimensions can also be adjusted according to design redundancy.

[0039] In some embodiments of the present invention, the number of axial oil channels 12 in the slot is equal to the number of layers of flat wire windings 2 in the stator slot 11. That is, one axial oil channel 12 is provided between every two adjacent layers of flat wire windings 2. This design ensures that each layer of flat wire conductor can obtain a direct cooling contact area, thereby maximizing the homogenization of the temperature gradient between the winding layers and avoiding the generation of local hot spots.

[0040] This invention provides an axial oil passage within the stator slot between adjacent layers of flat wire windings, allowing cooling oil to directly enter the stator slot and directly contact the surface of the straight winding section for heat exchange. Compared to existing technologies where cooling oil only flows through the oil passages in the core yoke or teeth and relies on the core for indirect heat conduction, this invention shortens the heat conduction path to almost zero, significantly reducing thermal resistance. This results in a substantial reduction in the operating temperature of the straight winding section under the same operating conditions, preventing the formation of localized hot spots and improving the motor's continuous output capability.

[0041] Furthermore, the axial oil channel 12 within the slot is continuous along the axial direction of the stator core 1. Both ends of the axial oil channel 12 extend to the two axial end faces of the stator core 1 and communicate with the external space. After the cooling oil completes its cooling task on the straight section of the flat wire winding 2, it flows out from the slot openings at both ends of the stator core 1. Since the flat wire winding 2 bends at both ends of the stator core 1 to form end windings, the cooling oil flowing out from the axial oil channel 12 within the slot will splash or spray onto the end surface of the flat wire winding 2 under the action of centrifugal force or gravity, providing further auxiliary spray cooling to the end area. Thus, this invention forms a composite cooling mode combining "direct cooling of the straight section by the oil channel within the slot" and "end spray cooling," completely covering the entire heat-generating area of ​​the flat wire winding 2.

[0042] The working process and cooling oil flow path of the oil cooling structure in the stator slot of the flat wire motor provided by the present invention are as follows: The cooling oil first enters the circumferential oil groove 311, which is defined by the outer circumferential surface of the circumferential oil groove core 31 and the inner wall of the motor housing, through the oil inlet on the motor housing. Since the circumferential oil groove 311 is a continuous annular cavity surrounding the stator axis, the cooling oil can quickly and evenly diffuse along the circumferential direction after entering, making the oil inlet pressure at various angle positions tend to be consistent.

[0043] Cooling oil filling the circumferential oil groove 311 flows radially inward into the guide hole 321 opened on the guide core 32 under the drive of the oil supply pressure. One end of the guide hole 321 is connected to the circumferential oil groove 311, and the other end extends radially inward to the bottom area of ​​the stator slot 11. After being guided by the guide hole 321, the cooling oil is directly transported to the interior of each stator slot 11 of the stator core 1, and then flows in the stator slot 11 to the two opposite ends of the two stator cores 1 respectively.

[0044] After entering the stator slot 11, the cooling oil immediately fills the axial oil channels 12 located between adjacent layers of flat wire windings 2. The axial oil channels 12 extend axially along the stator core 1, and the cooling oil flows axially towards both ends of the stator core 1 within them. During this axial flow, the cooling oil directly contacts the outer surface of the straight section of the flat wire winding 2 and undergoes forced convection heat transfer, rapidly carrying away the heat generated by copper loss in the flat wire winding 2, thus achieving efficient and direct cooling of the straight section of the winding.

[0045] The axial oil passage 12 inside the slot is arranged axially along the stator core 1, and its two ends extend to the two axial end faces of the stator core 1 respectively. After completing the cooling task of the straight section of the winding, the cooling oil flows out from the slot openings at both ends of the stator core 1. The flowing cooling oil splashes or sprays onto the end surface of the flat wire winding 2 under the action of centrifugal force or gravity, and provides further auxiliary cooling to the end area.

[0046] Thus, the present invention achieves circumferential pressure equalization of cooling oil through circumferential oil groove 311, radial introduction of cooling oil from the outside of the iron core to the inside of the stator groove 11 through guide hole 321, axial flow contact heat exchange between cooling oil and the straight section of winding through axial oil channel 12 in the groove, and finally end spray cooling through end oil outlet, forming a complete and efficient composite cooling oil circuit.

[0047] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0048] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0049] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0050] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0051] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0052] Although the above embodiments have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions and variations made to the above embodiments by those skilled in the art are within the protection scope of the present invention.

Claims

1. An oil cooling structure in the stator slot of a flat wire motor, characterized in that, include: A stator core (1) is provided with a plurality of stator slots (11) along the circumferential direction, and the stator slots (11) are axially connected along the stator core (1). Multiple flat wire windings (2) are respectively disposed in multiple stator slots (11); Oil supply assembly (3), which is connected to the stator slot (11), is used to supply cooling oil to the stator slot (11); The flat wire winding (2) is located in the stator slot (11), and the oil supply assembly (3) supplies cooling oil to the stator slot (11). The cooling oil is in direct contact with the flat wire winding (2) to cool the flat wire winding (2).

2. The oil cooling structure in the stator slot of the flat wire motor according to claim 1, characterized in that, There are two stator cores (1), and the oil supply assembly (3) is located between the two stator cores (1). The oil supply assembly (3) includes: A circumferential oil groove core (31) has an outer diameter smaller than that of the stator core (1) to form a circumferential oil groove (311) on the outer periphery of the circumferential oil groove core (31). A connecting groove (312) is provided in the circumferential oil groove core (31) and the connecting groove (312) is connected to the adjacent stator groove (11). A flow guide core (32) is provided on one side of the axial direction of the circumferential oil groove core (31). A flow guide hole (321) is provided on the flow guide core (32). One end of the flow guide hole (321) is connected to the circumferential oil groove (311), and the other end of the flow guide hole (321) is connected to the adjacent stator groove (11) and the connecting groove (312).

3. The oil cooling structure in the stator slot of the flat wire motor according to claim 2, characterized in that, The circumferential oil groove core (31) is provided with a plurality of connecting grooves (312) evenly distributed along the circumferential direction, and the plurality of connecting grooves (312) correspond one-to-one with the plurality of stator grooves (11).

4. The oil cooling structure in the stator slot of the flat wire motor according to claim 3, characterized in that, The flow guide core (32) is provided with a plurality of flow guide holes (321) evenly distributed along the circumferential direction. The plurality of flow guide holes (321) correspond one-to-one with the plurality of stator slots (11) and the plurality of connecting slots (312).

5. The oil cooling structure in the stator slot of the flat wire motor according to claim 4, characterized in that, The flow guide hole (321) extends radially inward from the outer peripheral surface of the flow guide core (32) to the bottom of the stator slot (11).

6. The oil cooling structure in the stator slot of the flat wire motor according to claim 2, characterized in that, The flat wire winding (2) passes through the stator slot (11), the connecting slot (312) and the guide hole (321), and the flat wire winding (2) is arranged in multiple layers radially in the stator slot (11).

7. The oil cooling structure in the stator slot of the flat wire motor according to claim 6, characterized in that, An axial oil passage (12) is formed between two adjacent flat wire windings (2). The axial oil passage (12) is located on the side wall of the stator slot (11). The axial oil passage (12) extends along the axial direction of the stator core (1). The cooling oil flows in the axial oil passage (12) and contacts the surface of the straight section of the flat wire winding (2).

8. The oil cooling structure in the stator slot of the flat wire motor according to claim 7, characterized in that, The cross-sectional shape of the axial oil passage (12) in the groove is one or more of the following: rectangular, semi-circular, triangular or trapezoidal.

9. The oil cooling structure in the stator slot of the flat wire motor according to claim 7, characterized in that, The number of axial oil passages (12) in the slot is equal to the number of layers of flat wire windings (2) in the stator slot (11), and each axial oil passage (12) in the slot is located between two adjacent layers of flat wire windings (2).

10. The oil cooling structure in the stator slot of the flat wire motor according to claim 7, characterized in that, The axial oil passage (12) in the groove runs through the axial direction of the stator core (1), and the two ends of the axial oil passage (12) in the groove extend to the two end faces of the stator core (1).

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