Stator core with cooling channels

Abstract

The invention provides a stator core with cooling channels. A cooling liquid channel (L) for cooling liquid to pass through is formed in the stator core, two axial ends of the stator core are respectively provided with a plurality of end oil injection channels (L0), the end oil injection channels (L0) are communicated with the cooling liquid channel (L), the cooling liquid channel (L) forms a cylindrical enveloping range in the stator core, and the end oil injection channels (L0) are communicated with the end oil injection channels (L0). Under the condition that the stator iron core is installed in place, the end oil injection channel (L0) is only located on the upper semicircular part of a cross section circle on the cross section circle perpendicular to the axial direction of the stator iron core. According to the invention, the end oil injection channel is only located at the upper semicircular part of the stator cross section circle, so that the amount of the cooling liquid injected to the winding coil is larger under the same cooling liquid flow, and the part of the cooling liquid can be distributed to the whole winding coil by virtue of gravity after being injected, so that the cooling liquid is more fully utilized.

Description

Technical Field

[0001] The present invention relates to the field of electric motors, and more particularly to a stator core with a cooling channel. Background Art

[0002] The applicant proposed a stator core in a prior application with application number CN202411365264.7, in which the slots located in the second lamination have an inner extension, which is used to guide the coolant to the position near the end coil of the winding and with greater gravitational potential energy to provide a better cooling effect. However, in actual application, it is found that the cooling effect of the coolant located in the lower semicircular part of the stator cross section sprayed to the coil still needs to be improved. Summary of the invention

[0003] The object of the present invention is to overcome or at least alleviate the deficiencies of the above-mentioned prior art and to provide a stator core with a cooling channel.

[0004] The present invention provides a stator core with a cooling channel, wherein a cooling liquid channel for passing a cooling liquid is formed inside the stator core, and a plurality of end oil injection channels are formed at two axial ends of the stator core, wherein the end oil injection channels are connected to the cooling liquid channel. The coolant channel forms a cylindrical envelope inside the stator core. When the stator core is installed in place, on a cross-sectional circle perpendicular to the axial direction of the stator core, the end oil injection channel is only located in the upper semicircular portion of the cross-sectional circle.

[0005] In at least one embodiment, when the stator core is installed in place, on a cross-sectional circle perpendicular to the axial direction of the stator core, the end oil injection channel is only located in a sector-shaped area with a central angle of 120° in the upper middle of the cross-sectional circle.

[0006] In at least one embodiment, along the spraying direction of the coolant, the end oil spray channel is inclined from the outer peripheral side to the inner peripheral side.

[0007] In at least one embodiment, the stator core includes a core body and end punching sheets, a group of end punching sheets are respectively provided at two axial ends of the core body, the coolant channel is formed at the yoke of the core body, and the end oil injection channel is formed at the yoke of the end punching sheets. Each group of end punching sheets includes a plurality of punching sheets with the same structure, each punching sheet includes a plurality of groups of oil holes, and different groups of oil holes have different radial distances from the edge of the punching sheet. The oil holes aligned in the circumferential direction of two axially adjacent punching plates in each group of the end punching plates belong to different groups of oil holes.

[0008] In at least one embodiment, the stator core includes a core body and end punching sheets, a group of end punching sheets are respectively provided at two axial ends of the core body, the coolant channel is formed at the yoke of the core body, and the end oil injection channel is formed at the yoke of the end punching sheets. The axial end of the core body is formed with a plurality of main body oil holes and a plurality of flow-concentrating oil holes, and both the main body oil holes and the flow-concentrating oil holes are communicated with the coolant channel. The converging oil hole is communicated with the end oil injection channel, and the main body oil hole is blocked by the end punching sheet and is not connected with the end oil injection channel.

[0009] In at least one embodiment, the coolant channel includes a plurality of sub-channels and is in a maze shape, and adjacent sub-channels are not aligned in the axial direction or the circumferential direction. The oil converging hole comprises a connected circumferential section and an inner leading section, wherein the inner leading section is located radially inward of the circumferential section. The circumferential section of each of the oil converging holes is communicated with a plurality of the sub-channels adjacent to each other in the circumferential direction, and the inner lead section of each of the oil converging holes is communicated with one of the end oil injection channels.

[0010] In at least one embodiment, the liquid inlet of the coolant channel is located in the axial middle of the core body, and, When the stator core is installed in place, the liquid inlet is located at the lowest point of the core body.

[0011] In at least one embodiment, the axial length of the sub-channel located in the middle region in the axial direction is greater than the axial length of the sub-channel located close to the end in the axial direction.

[0012] In at least one embodiment, a circumferential width of a sub-channel radially close to the liquid inlet is greater than a circumferential width of a sub-channel radially far from the liquid inlet.

[0013] In at least one embodiment, the circumferential width of the sub-channel located at the endmost portion in the axial direction is greater than the circumferential width of the axially inner sub-channel.

[0014] According to the present invention, the end oil injection channel is only located in the upper semicircle of the stator cross-section circle, so that under the same coolant flow rate, the amount of coolant sprayed to the winding coil is larger. After spraying, this part of coolant can be distributed to the entire winding coil by gravity, so that the coolant is more fully utilized. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a schematic diagram of a stator core according to one embodiment of the present application.

[0016] Figure 2yes Figure 1 Schematic diagram of an axial section.

[0017] Figure 3 yes Figure 1 A partially exploded schematic diagram of a block ...

[0018] Figure 4 yes Figure 1 Schematic diagram of the middle core body cut apart along the circumferential direction.

[0019] Figure 5 yes Figure 4 A schematic diagram of a corresponding partially enlarged portion of a stator core that is partially cut away.

[0020] Figure 6 yes Figure 3 A schematic diagram of a partial enlargement of the corresponding stator core body cut along the circumferential direction.

[0021] Figure 7 It is a schematic diagram of cross sections of a core body of a stator core in three different sections according to one embodiment of the present application.

[0022] Figure 8 It is a schematic diagram of a stator core according to an embodiment of the present application with an end punching sheet at one end removed.

[0023] Fig. 9 It is a schematic diagram of a cross section of an iron core body of a stator iron core according to one embodiment of the present application at a second section of the body.

[0024] Fig.10 1 is a schematic diagram of cross sections of three end punching sheets of a stator core according to one embodiment of the present application.

[0025] Fig.11 is a partially cutaway schematic diagram of a stator core according to one embodiment of the present application.

[0026] Fig.12 is a schematic diagram of cross sections of three end sheets of a stator core according to another possible embodiment of the present application.

[0027] Description of reference numerals: S0: iron core body; S01: first section of the body; S02: second section of the body; S03: third section of the body; S1 end punch; S11 outer punch; S12 middle punch; S13 inner punch; R1 first zone; R2 second zone; R3 third zone; H1 oil hole in the first zone; H2 oil hole in the second zone; H3 oil hole in the third zone; H4 main oil hole; H5 convergent oil hole; H51 circumferential section; H52 inner lead section; L coolant channel; L0 end oil injection channel; E liquid inlet; D1 top channel gap; D2 bottom channel gap; D3 middle channel gap; D4 end channel gap. DETAILED DESCRIPTION

[0028] The exemplary embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood that these specific descriptions are only used to teach those skilled in the art how to implement the present invention, and are not intended to exhaust all possible modes of the present invention, nor to limit the scope of the present invention.

[0029] Reference Figures 1 to 12 , a stator core with a cooling channel according to one embodiment of the present application is introduced.

[0030] Unless otherwise specified, the axial, radial and circumferential directions referred to below are all based on the axial, radial and circumferential directions of the stator core. The state in which the stator core is installed in place refers to the position of the motor in a normal working state, in which the motor is horizontally arranged in the axial direction.

[0031] Reference Figures 1 to 5 The stator core provided in this embodiment includes a core body S0 and two groups of end punching sheets S1 located at two axial ends of the core body S0.

[0032] Each group of end punches S1 includes three punches, which are, from the axial outer side to the axial inner side, the outer punch S11, the middle punch S12 and the inner punch S13.

[0033] The core body S0 is composed of a plurality of sections, each of which is formed by stacking a plurality of punching sheets. It should be understood that in other possible embodiments, each section may also be an integrally formed part, which is, for example, pressed from a soft magnetic material. In this embodiment, the plurality of sections of the core body S0 are divided into a first main body section S01 located in the middle of the axial direction, a second main body section S02 located at the end of the axial direction, and a plurality of third main body sections S03 located between the first main body section S01 and the second main body section S02.

[0034] The yoke of each segment is formed with a plurality of main body oil holes H4 distributed in the circumferential direction. The main body oil holes H4 on the axially adjacent segments are connected to each other in a manner that is not completely aligned in the circumferential direction, so that a tortuous maze-like coolant channel L is formed inside the core body S0. The coolant channel L is almost distributed throughout the core body S0 in the circumferential and axial directions, forming a cylindrical envelope range. The coolant can flow in the coolant channel L to take away the heat of the stator core.

[0035] Some oil holes on the second section S02 of the main body are special, and these oil holes are called concentrated oil holes H5. The concentrated oil holes H5 are connected to the coolant channel L and serve as the channel for the coolant to be finally ejected from the end of the core body S0, so as to transport the coolant to the winding coil (not shown in the figure) at the end of the stator core to take away the heat of the winding coil. Figure 5 The dashed arrow a in FIG. 1 shows the coolant being ejected through the convergent oil hole H5 .

[0036] The reader can understand from the following description that the main body oil hole H4 on the second section S02 of the main body will be blocked by the end punch S1, and the coolant is not allowed to be ejected from the end through the main body oil hole H4. Figure 5 As shown in the dotted arrow b, the main body oil hole H4 on the second section S02 of the main body has the purpose of allowing the coolant to flow evenly along the circumferential direction in the channel formed by these oil holes closed at one end, so that the second section S02 of the main body can be exposed to the coolant in the entire circumferential direction, providing good cooling for the second section S02 of the main body.

[0037] The liquid inlet E of the coolant channel L is set in the first section S01 of the main body. When the stator core is in the installed position, the liquid inlet E is located in the middle of the lower part of the core body S0, or in other words, at the lowest point of the core body S0. The coolant enters the core body S0 from the bottom, and then flows in the coolant channel L in both the circumferential and axial directions. This flow sequence from bottom to top and from the axial middle to both sides is more conducive to the uniform distribution of the coolant in the coolant channel L, thereby providing uniform cooling for each area of ​​the core body S0. Figure 4 The dashed arrows in the figure are used to indicate the flow direction of the coolant.

[0038] Reference Figures 4 to 6 In this embodiment, the coolant channels L are also distributed in different sizes at different positions, so as to guide the coolant to flow smoothly from the liquid inlet E to the upper part and two axial ends of the core body S0. The arrow U in the figure points to the upper part of the stator core installed in place, which is referred to as the upper part below.

[0039] In the following, the area where each oil hole of each section is located is referred to as a sub-channel of the coolant channel L. Among the multiple sections of the core body S0, the axial length of the first section S01 of the main body is the largest. This makes the liquid storage capacity of the sub-channel on the first section S01 of the main body greater than the liquid storage capacity of the sub-channel connected to it and located in the third section S03 of the main body, and the coolant entering the coolant channel L is stabilized in these sub-channels. The pressure of the coolant in these sub-channels is sufficient to squeeze the coolant to the surroundings, so that the coolant has a tendency to flow to the two axial ends after entering the first section S01 of the main body. In other possible embodiments, the axial length of each sub-channel can also be set as follows: the axial length of the sub-channel located in the middle area in the axial direction is greater than the axial length of the sub-channel close to the end in the axial direction.

[0040] Then observe the circumferential width of each sub-channel.

[0041] On the one hand, for the same section of the core body S0, the circumferential width of the subchannel located in the area where the liquid inlet E is located (also called the bottom channel) and the subchannel in the area directly above the liquid inlet E (also called the top channel) is greater than the circumferential width of other subchannels. In the figure, it is shown that the bottom channel gap D2 and the top channel gap D1 are both greater than the middle channel gap D3. This makes the liquid storage volume of the subchannel near the liquid inlet E greater than the liquid storage volume of the subchannels on both sides of it in the circumferential direction, so that the coolant has a tendency to flow to both sides of the circumference after entering the liquid inlet E; and the liquid storage volume of the subchannel at the top increases again, so that a temporary liquid storage area is formed at the top, and the coolant in this part has greater gravitational potential energy, and has greater kinetic energy when it is subsequently ejected from the end of the stator core. In other possible embodiments, the circumferential width of each subchannel can also be set as follows: the circumferential width of the subchannel close to the liquid inlet E in the radial direction is greater than the circumferential width of the subchannel far away from the liquid inlet E in the radial direction.

[0042] On the other hand, for different sections, or for sub-channels at different positions in the axial direction, they meet such a setting that the circumferential width of the sub-channel at the end in the axial direction is greater than the circumferential width of the axial inner sub-channel (except for the sub-channel at the liquid inlet E and above the first section S01 of the main body). In the figure, it is shown that the end channel gap D4 is greater than the middle channel gap D3. This makes the liquid storage volume in the end sub-channel larger again, so that the coolant in this part has greater gravitational potential energy, and has greater kinetic energy when it is subsequently ejected from the end of the stator core.

[0043] Next, refer to Figures 7 to 9 The specific position and structure of the oil converging hole H5 are further explained.

[0044] Reference Figure 7When the stator core is installed in place, a cross section perpendicular to the axial direction of the stator core is made to obtain a cross section circle. The oil concentrating hole H5 is located in a sector area with a central angle of 120° in the middle of the upper part of the cross section circle.

[0045] The central angle of the sector area is selected as 120°, which is particularly suitable for the case where the number of slots of the stator core is a multiple of 3, for example, the number of slots is 48 or 54. This will be more easily understood when the structure of the end punching sheet S1 is introduced below. It should be understood that when the number of slots is other numbers, the central angle of the sector area can also be appropriately adjusted, for example, it can be selected between 90° and 180°. According to the principle of the present application that the externally injected coolant can contact the winding coil as much as possible, the sector area is only located in the upper half of the cross-sectional circle.

[0046] Each converging oil hole H5 is roughly T-shaped or sickle-shaped, and includes a circumferential section H51 and an inner section H52. The circumferential section H51 is in an arc shape on the cross-sectional circle, and the inner section H52 is located radially inward of the circumferential section H51. For the converging oil hole H5 located in the middle of the highest point of the cross-sectional circle, the inner section H52 is preferably connected to the middle of the circumferential section H51 in the circumferential direction, that is, the inner section H52 is located at the highest point radially inward of the circumferential section H51. For the converging oil hole H5 located at both circumferential ends of the fan-shaped area, the inner section H52 is preferably connected to the circumferential end of the circumferential section H51, or the inner section H52 is connected to the lowest point of the circumferential section H51, which makes the coolant outlet area in the designed 120° fan-shaped area. For other converging oil holes H5, the inner extension section H52 can be connected to any circumferential position of the circumferential section H51; preferably, the circumferential spacing between adjacent inner extension sections H52 is close to uniform, so that the emitted coolant is distributed more evenly.

[0047] Next, combine Figure 1 , Fig.10 and Fig.11 The specific structure of the end punching sheet S1 and the characteristics of the end oil injection channel L0 provided by it are introduced.

[0048] Reference Figure 1 , the end punching sheet S1 is divided into three sector-shaped areas in the circumferential direction, and the central angle of each sector-shaped area is 120°. When the stator core is in the installed position, the first area R1 is the upper area of ​​the end punching sheet S1 (the phase is the same as the area where the oil concentrating hole H5 is located), the second area R2 is the lower left area of ​​the end punching sheet S1, and the third area R3 is the lower right area of ​​the end punching sheet S1.

[0049] Fig.10The cross-sectional shapes of the outer punch S11, the middle punch S12 and the inner punch S13 are shown schematically, and only one oil hole is shown in each sector in a simplified form, namely the first sector oil hole H1, the second sector oil hole H2 and the third sector oil hole H3. It should be understood that each sector actually has multiple oil holes, and the oil holes in the same sector have the same radial position, while the oil holes in different sectors have different radial positions. It should be understood that Fig.10 The shape and size ratio of the oil hole in the figure are not equal to the actual situation. In this embodiment, the oil hole on the end punch S1 is roughly oblong, which has the function of guiding the emitted coolant to the radial inside; but the oblong shape is not necessary, and the oil hole on the end punch S1 can also have other shapes.

[0050] The first zone oil hole H1 located in the first zone R1 has an edge distance d1 from the end punch S1, the second zone oil hole H2 located in the second zone R2 has an edge distance d2 from the end punch S1, and the third zone oil hole H3 located in the third zone R3 has an edge distance d3 from the end punch S1, d1>d2>d3.

[0051] from Fig.10 It can be found that the outer punching sheet S11, the middle punching sheet S12 and the inner punching sheet S13 are actually punching sheets with the same structure, but when installed, their phase angles relative to the core body S0 are different. Fig.10 For reference, the middle punch S12 is rotated 120° counterclockwise relative to the outer punch S11 , and the inner punch S13 is rotated 120° counterclockwise relative to the middle punch S12 .

[0052] Reference Fig.11 After the three punches are stacked together, the first zone oil hole H1 of the outer punch S11, the second zone oil hole H2 of the middle punch S12 and the third zone oil hole H3 of the inner punch S13 are aligned in the circumferential direction, but the three oil holes form a stepped channel in the radial direction, which is hereinafter referred to as the end oil injection channel L0. Along the injection direction of the coolant ( Fig.11 The dotted arrow in the figure represents the spray direction of the coolant), and the end oil spray channel L0 is inclined from the outer peripheral side to the inner peripheral side, so that the coolant can be sprayed to the winding package located on the inner side of the end of the stator core.

[0053] At this point, the reader can also understand that this embodiment realizes the function of using one punching sheet to construct an inclined end oil injection channel L0 by setting oil holes in three areas on the end punching sheet S1 and installing the three end punching sheets S1 in a manner of deflecting phase angles.

[0054] As mentioned above when introducing the flow-converging oil hole H5, the solution of this embodiment of dividing the end punching sheet S1 into three equally divided fan-shaped areas to arrange oil holes at different positions is particularly suitable for the case where the number of line slots of the stator core is a multiple of 3, such as the case where the number of line slots is 48 or 54. When the number of line slots is other numbers, the number of fan-shaped areas, the degree of the central angle, and the number of end punching sheets S1 in each group can also be adjusted appropriately. Usually, the number of fan-shaped areas on each end punching sheet S1 is equal to the number of punching sheets in a group of end punching sheets S1. In addition, the division of the fan-shaped areas of different oil holes of the end punching sheet S1 matches the division of the fan-shaped area where the flow-converging oil hole H5 is located.

[0055] It is worth noting that only the third zone oil hole H3 on the inner punch S13 is connected to the coolant channel L, and the first zone oil hole H1 and the second zone oil hole H2 on the inner punch S13 are not connected to the coolant channel located on the axial inner side of the core body S0. The reason has been mentioned above, because the main body oil hole H4 on the second section S02 of the main body will be blocked by the end punch S1 (specifically the inner punch S13). Therefore, the coolant finally only ejects from the first zone R1 of the outer punch S11, and the coolant in this area falls to the upper part of the winding coil, and flows along the annular winding coil under the action of gravity to dissipate heat for the winding coil. On the one hand, this ensures that the winding wire package can be exposed to the coolant; on the other hand, compared with the solution of ejecting coolant from the entire annular area of ​​the outer punch S13, when the coolant flow rate is constant, more coolant can be provided in the first zone R1, so that the winding wire package as a whole can be exposed to more coolant, or the amount of coolant that does not hit the winding wire package is as small as possible, thereby improving the cooling effect.

[0056] Reference Fig.12 Since the coolant only needs to be emitted from the upper 1 / 3 area of ​​the outer punch S13, in other possible implementations, oil holes can also be set only in the 1 / 3 fan-shaped area of ​​each end punch S1, that is, the outer punch S11 only has the first area oil hole H1, the middle punch S12 only has the second area oil hole H2, and the inner punch S13 only has the third area oil hole H3. It can be found that this setting method makes the end punch S1 have three different structures, which will increase the number of parts, increase mold costs and the complexity of parts management.

[0057] It should be understood that the above-mentioned embodiments and some aspects or features thereof may be appropriately combined.

[0058] The present invention has at least one of the following advantages: (i) The end oil injection channel is only in the upper half of the stator cross-section circle, especially in the upper 120° circumferential range, so that at the same coolant flow rate, a larger amount of coolant is sprayed onto the winding package. After injection, this part of coolant can be distributed to the entire winding package by gravity, making fuller use of the coolant and higher cooling efficiency.

[0059] (ii) The end punching plates are stacked by rotating the phase angle to form an end oil injection channel that is inclined radially inward. The end punching plates have the same structure, which reduces the complexity of the parts.

[0060] (iii) The labyrinth-shaped coolant channel allows the coolant to be evenly distributed over the approximate periphery of the stator core, thereby providing good cooling for the core.

[0061] (iv) The coolant channels have different lengths and / or widths at different locations inside the core, so that the coolant can be guided to flow from the liquid inlet at the lower portion of the stator core to the upper portion and to both ends.

[0062] Of course, the present invention is not limited to the above-mentioned embodiments, and those skilled in the art may make various modifications to the above-mentioned embodiments of the present invention under the guidance of the present invention without departing from the scope of the present invention.

Claims

1. A stator core having a cooling channel, wherein a cooling liquid channel (L) for passing a cooling liquid is formed inside the stator core, and a plurality of end oil injection channels (L0) are formed at two axial ends of the stator core, and the end oil injection channels (L0) are connected to the cooling liquid channel (L), characterized in that: The coolant channel (L) forms a cylindrical envelope inside the stator core. When the stator core is installed in place, on a cross-sectional circle perpendicular to the axial direction of the stator core, the end oil injection channel (L0) is only located in the upper semicircular portion of the cross-sectional circle.

2. The stator core with cooling channel according to claim 1, characterized in that: When the stator core is installed in place, on a cross-sectional circle perpendicular to the axial direction of the stator core, the end oil injection channel (L0) is only located in a sector-shaped area with a central angle of 120° in the upper middle of the cross-sectional circle.

3. The stator core with cooling channel according to claim 1, characterized in that: Along the spraying direction of the coolant, the end oil spray channel (L0) is inclined from the outer peripheral side to the inner peripheral side.

4. The stator core with cooling channel according to claim 3, characterized in that: The stator core comprises a core body (S0) and end punching sheets (S1), a group of end punching sheets (S1) are respectively provided at two axial ends of the core body (S0), the coolant channel (L) is formed at the yoke of the core body (S0), and the end oil injection channel (L0) is formed at the yoke of the end punching sheet (S1). Each group of end punching sheets (S1) comprises a plurality of punching sheets with the same structure, each of the punching sheets comprises a plurality of groups of oil holes, and different groups of oil holes have different radial distances from the edge of the punching sheet. The oil holes aligned in the circumferential direction of two axially adjacent punching plates in each group of the end punching plates (S1) belong to different groups of oil holes.

5. The stator core with cooling channel according to claim 1, characterized in that: The stator core comprises a core body (S0) and end punching sheets (S1), a group of end punching sheets (S1) are respectively provided at two axial ends of the core body (S0), the coolant channel (L) is formed at the yoke of the core body (S0), and the end oil injection channel (L0) is formed at the yoke of the end punching sheet (S1). The axial end of the core body (S0) is formed with a plurality of main body oil holes (H4) and a plurality of flow-gathering oil holes (H5), and both the main body oil holes (H4) and the flow-gathering oil holes (H5) are in communication with the coolant channel (L). The converging oil hole (H5) is connected to the end oil injection channel (L0), and the main body oil hole (H4) is blocked by the end punching sheet (S1) and is not connected to the end oil injection channel (L0).

6. The stator core with cooling channels according to claim 5, characterized in that: The coolant channel (L) includes a plurality of sub-channels and is in a maze shape, and adjacent sub-channels are not aligned in the axial direction or the circumferential direction. The oil converging hole (H5) comprises a connected circumferential section (H51) and an inner leading section (H52), wherein the inner leading section (H52) is located radially inward of the circumferential section (H51). The circumferential section (H51) of each of the oil converging holes (H5) is connected to a plurality of circumferentially adjacent sub-channels, and the inner lead section (H52) of each of the oil converging holes (H5) is connected to one of the end oil injection channels (L0).

7. The stator core with cooling channels according to claim 6, characterized in that: The liquid inlet (E) of the cooling liquid channel (L) is located in the axial middle of the core body (S0), and, When the stator core is installed in place, the liquid inlet (E) is located at the lowest point of the core body (S0).

8. The stator core with cooling channels according to claim 7, characterized in that: The axial length of the sub-channel located in the middle region in the axial direction is greater than the axial length of the sub-channel located close to the end in the axial direction.

9. The stator core with cooling channels according to claim 7, characterized in that: The circumferential width of the sub-channel closer to the liquid inlet (E) in the radial direction is greater than the circumferential width of the sub-channel farther from the liquid inlet (E) in the radial direction.

10. The stator core with cooling channels according to claim 9, characterized in that: The circumferential width of the sub-channel located at the endmost portion in the axial direction is greater than the circumferential width of the axially inner sub-channel.

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