Motor casing and motor

Abstract

The invention provides a motor shell. The motor shell comprises an inner shell and an outer shell, a plurality of flow guide ribs extending in the circumferential direction are arranged on the outer surface of the inner shell to form a cooling water channel; the first end of the motor shell is provided with a water inlet and a water outlet; the cooling water channel comprises a first water channel and a second water channel; the first water channel communicates with the water inlet at the first end, and the second water channel communicates with the water outlet at the first end; the first water channel and the second water channel are communicated at the second end of the motor shell; the first water channels and the second water channels are alternately arranged in the axial direction; the inner surface of the outer shell is a conical surface; in the axial direction, the heights of the flow guide ribs are gradually increased in the inner diameter increasing direction of the inner surface of the outer shell. The invention also provides a motor comprising the motor casing. The cooling and heat dissipation efficiency of the motor is improved, the assembly process of the motor is simplified, and the cost is saved.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of electric machines, and in particular to an electric machine housing and an electric machine comprising the same. BACKGROUND

[0002] With the development of new energy engineering machinery, the power density of electric machines is becoming larger and larger. The increase of power density of electric machines is accompanied by the increase of heat generation of electric machines, and higher and higher requirements are put forward for the heat dissipation performance of electric machines. For example, new energy engineering machinery including new energy mine trucks applied in mines has higher requirements for power density of electric machines, and whether the electric machines can effectively dissipate heat becomes an important factor restricting the full play of the performance of electric machines.

[0003] However, the heat dissipation of electric machines has problems such as low heat exchange efficiency, high energy consumption and complex structure, which cannot meet the heat dissipation requirements of high-performance electric machines. SUMMARY

[0004] The present disclosure provides an electric machine housing and an electric machine comprising the same.

[0005] In a first aspect, the present disclosure provides an electric machine housing, comprising an inner housing and an outer housing; a plurality of flow guide ribs extending in the circumferential direction are arranged on the outer surface of the inner housing, forming a cooling water channel; a water inlet and a water outlet are arranged at the first end of the electric machine housing; the cooling water channel comprises a first water channel and a second water channel; the first water channel is in communication with the water inlet at the first end, and the second water channel is in communication with the water outlet at the first end; the first water channel and the second water channel are in communication at the second end of the electric machine housing; the first water channel and the second water channel are arranged alternately in the axial direction; the inner surface of the outer housing is a conical surface; in the axial direction, the height of the flow guide rib increases in the direction of increasing inner diameter of the inner surface of the outer housing.

[0006] In some embodiments, the outer diameter surface of the flow guide rib is a conical surface, and the outer diameter surfaces of the plurality of flow guide ribs are on the same conical surface.

[0007] In some embodiments, the taper of the outer diameter surface of the flow guide rib ranges from 0° to 1°.

[0008] In some embodiments, the taper of the outer diameter surface of the flow guide rib is positively correlated with the length of the electric machine housing in the axial direction.

[0009] In some embodiments, the outer diameter surface of the flow guide rib is in interference fit with the inner surface of the outer housing.

[0010] In some embodiments, in the axial direction, the spacing between the flow guide ribs decreases in the direction of increasing inner diameter of the inner surface of the outer housing.

[0011] In some embodiments, the cooling water channel has a uniform cross-sectional area at different positions.

[0012] In some embodiments, the guide ribs comprise guide portions and transition portions; the guide portions extend in a circumferential direction perpendicular to an axial direction; the transition portions extend in a direction intersecting the circumferential direction; and the transition portions are connected to the guide portions at two ends thereof, respectively.

[0013] In some embodiments, the transition portions extend in a direction parallel to the axial direction, and the transition portions are smoothly connected to the guide portions.

[0014] In some embodiments, the first water channel is provided with at least one first shunt rib for separating a portion of the first water channel close to the water inlet into a plurality of first sub-water channels; and / or, the second water channel is provided with at least one second shunt rib for separating a portion of the second water channel close to the water outlet into a plurality of second sub-water channels.

[0015] In some embodiments, the water inlet and the water outlet are arranged on opposite sides of the first end; the second water channel comprises an expansion portion in communication with the water outlet, and the expansion portion is provided with at least one third shunt rib.

[0016] In some embodiments, the plurality of third shunt ribs separate the expansion portion into a plurality of third sub-water channels, and the sum of cross-sectional areas of the plurality of third sub-water channels is consistent with the cross-sectional area of the cooling water channel.

[0017] In some embodiments, the inner shell comprises an inner cylindrical portion and an inner end cover portion arranged at one end of the inner cylindrical portion, and the inner cylindrical portion and the inner end cover portion are in an integrated structure; the outer shell comprises an outer cylindrical portion and an outer end cover portion arranged at one end of the outer cylindrical portion, and the outer cylindrical portion and the outer end cover portion are in an integrated structure; and the inner end cover portion and the outer end cover portion are arranged at opposite ends of the motor housing.

[0018] In some embodiments, the inner shell is provided with a first connecting portion at one end close to the inner end cover portion, the outer shell is provided with a second connecting portion at one end away from the outer end cover portion, and the first connecting portion and the second connecting portion are fixedly connected by bolts.

[0019] In some embodiments, the outer surface of the inner cylindrical portion is provided with a sealing ring at each end thereof.

[0020] In a second aspect, the embodiments of the present disclosure provide a motor, which comprises a motor housing, a stator and a rotor, the stator and the rotor are installed in the motor housing, and the motor housing is the motor housing according to the first aspect of the embodiments of the present disclosure.

[0021] In the embodiment of the present disclosure, the cold / heat water channels in the motor shell are arranged alternately adjacent to each other, and the flow directions of the cooling liquids in the cold / heat water channels are opposite, so that the temperature difference of the cooling liquids always exists and is large, thereby being capable of improving the cooling efficiency; the inner and outer shells are interference-fitted through the conical surface structure, greatly saving the assembly process cost, improving the production efficiency of the motor shell, reducing the labor cost, and also being capable of reducing the risk of water leakage between adjacent cooling water channels. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a structural schematic diagram of a motor shell in the embodiment of the present disclosure;

[0023] Figure 2 is a structural schematic diagram of another motor shell in the embodiment of the present disclosure;

[0024] Figure 3 is a structural schematic diagram of an inner shell in the embodiment of the present disclosure;

[0025] Figure 4 is a schematic diagram of a transition structure in the embodiment of the present disclosure;

[0026] Figure 5 is a schematic diagram of a water channel structure in the form of countercurrent heat exchange in the embodiment;

[0027] Figure 6 is a schematic diagram of a one-way spiral parallel flow heat exchange water channel. DETAILED DESCRIPTION

[0028] In order for those skilled in the art to better understand the technical solutions of the present disclosure, the technical solutions of the present disclosure will be described in detail below with reference to the drawings.

[0029] In the following, example embodiments will be described more fully with reference to the accompanying drawings, in which example embodiments can be embodied in different forms and should not be construed as being limited to the embodiments set forth herein. Instead, the purpose of providing these embodiments is to make the present disclosure thorough and complete and to fully convey the scope of the present disclosure to those skilled in the art.

[0030] In the case of no conflict, each embodiment of the present disclosure and each feature in the embodiments can be combined with each other.

[0031] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0032] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0033] Embodiments described herein can be described with reference to plan views and / or cross-sectional views by virtue of the fact that the disclosure equally contemplates method embodiments. Accordingly, the example illustrations are merely meant to be illustrative and other example illustrations can be contemplated. Thus, the embodiments are not limited to the example illustrations depicted in the figures, but rather the embodiments are intended to include modifications that are based on the manufacturing processes and / or tolerances. Therefore, the shapes of the regions illustrated in the figures are illustrative and other shapes are possible that are based on the manufacturing processes and / or tolerances. The embodiments are not limited to the illustrated example shapes, but rather the embodiments are intended to include modifications that are based on the manufacturing processes and / or tolerances.

[0034] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure and will not be interpreted in an overly literal or overly formal sense unless expressly so defined herein.

[0035] Figure 1 is a schematic view of a motor housing in an embodiment of the disclosure.

[0036] As Figure 1 shown, the motor housing comprises an inner shell 1 and an outer shell 2; a plurality of circumferentially extending flow guide ribs 3 are arranged on the outer surface of the inner shell 1; the flow guide ribs 3 and the outer surface of the inner shell 1 and the inner surface of the outer shell 2 together form a cooling water channel; a water inlet and a water outlet are arranged at the first end of the motor housing; the cooling water channel comprises a first water channel 4 and a second water channel 5; the first water channel 4 is in communication with the water inlet at the first end, and the second water channel 5 is in communication with the water outlet at the first end; the first water channel 4 and the second water channel 5 are in communication at the second end of the motor housing; the first water channel 4 and the second water channel 5 are arranged alternately in the axial direction. For example, as Figure 2 shown, the first water channel 4 is composed of a water channel 41, a water channel 42 and a water channel 43, and the second water channel 5 is composed of a water channel 51, a water channel 52 and a water channel 53; the water channel 41, the water channel 42 and the water channel 43 are arranged alternately with the water channel 51, the water channel 52 and the water channel 53.

[0037] As Figure 2As shown, the cooling liquid enters the cooling water channel from the water inlet, flows along the first water channel 4 to the second end of the motor casing; then the cooling liquid enters the second water channel 5 at the second end, flows along the second water channel 5 to the first end of the motor casing, and flows out from the water outlet; the flow directions of the cooling liquid in the first water channel 4 and the second water channel 5 are opposite, and the temperature of the cooling liquid in the first water channel 4 is lower than that in the second water channel 5, forming a water channel structure in the form of counter-flow heat exchange. According to the counter-flow heat exchange principle, the cold water channel and the hot water channel are arranged alternately, the flow directions of the cooling liquid in the cold water channel and the hot water channel are opposite, so that the temperature difference of the cooling liquid always exists and is large, thereby improving the cooling efficiency.

[0038] As shown in the figure, Figure 1 The inner surface of the outer shell 2 is a conical surface, and the height of the flow guide rib 3 increases in the direction in which the inner diameter of the inner surface of the outer shell 2 increases in the axial direction. In some embodiments, the outer diameter surface of the arranged flow guide rib 3 on the outer surface of the inner shell 1 is substantially a conical surface as a whole, and during assembly, the assembly can be completed by applying pressure to make the outer diameter surface of the flow guide rib 3 form an interference fit with the inner surface of the outer shell 2, without the need to heat the outer shell 2 to a certain temperature to make it expand, then assemble the inner shell 1 into the outer shell 2, or use friction stir welding to fix and seal the inner and outer shells, greatly saving the assembly process cost, improving the production efficiency of the motor casing, and reducing the labor cost; the outer diameter surface of the flow guide rib 3 is in close contact with the inner surface of the outer shell 2, which can also reduce the risk of water leakage between adjacent cooling water channels.

[0039] In some embodiments, as shown in the figure, Figure 1 The outer diameter surface of the flow guide rib 3 is a conical surface, and the outer diameter surfaces of multiple flow guide ribs are on the same conical surface. The conical surface matches the conical surface of the inner surface of the outer shell 2 in size, taper, etc., and the inner surface of the outer shell 2 and the outer diameter surface of the flow guide rib 3 form a conical surface structure with a draft angle, making the assembly of the inner shell 1 and the outer shell 2 easier. By setting the outer diameter surface of the flow guide rib 3 as a conical surface, the mating area of the outer diameter surface of the flow guide rib 3 and the inner surface of the outer shell 2 is increased, which is beneficial to reduce the interference stress of the flow guide rib 3 and the outer shell, and avoid material yield failure.

[0040] In the embodiments of the present disclosure, the taper of the outer diameter surface of the flow guide rib 3 ranges from 0° to 1°; the taper of the inner surface of the outer shell 2 is consistent with the taper of the outer diameter surface of the flow guide rib 3, and its range is also from 0° to 1°. In some embodiments, the taper of the outer diameter surface of the flow guide rib 3 is 0.75°, and the taper of the inner surface of the outer shell 2 is 0.75°.

[0041] In the embodiments of the present disclosure, the taper of the outer diameter surface of the guide fin 3 and the taper of the inner surface of the outer shell 2 can be set according to the axial length of the motor shell. In some embodiments, the taper of the outer diameter surface of the guide fin is positively correlated with the axial length of the motor shell. For example, the longer the length of the motor shell, the larger the taper of the outer diameter surface of the guide fin can be set.

[0042] As shown in Figure 2 , the inner shell 1 includes an inner cylindrical portion 11 and an inner end cover portion 12 arranged at one end of the inner cylindrical portion 11, and the inner cylindrical portion 11 and the inner end cover portion 12 are in an integrated structure, and the guide fin 3 is arranged on the outer surface of the inner cylindrical portion 11.

[0043] The outer shell 2 includes an outer cylindrical portion 21 and an outer end cover portion 22 arranged at one end of the outer cylindrical portion 21, and the outer cylindrical portion 21 and the outer end cover portion 22 are in an integrated structure, and the inner surface of the outer cylindrical portion 21 is tapered.

[0044] After the inner shell 1 and the outer shell 2 are assembled, the inner end cover portion 12 and the outer end cover portion 22 are respectively located at opposite ends of the motor shell.

[0045] In the embodiments of the present disclosure, the inner shell 1 is an integrated structure integrating the inner cylindrical portion 11 and the inner end cover portion 12, and the outer shell 2 is an integrated structure integrating the outer cylindrical portion 21 and the outer end cover portion 22, so that the inner and outer shells do not need to be fixed and sealed by friction stir welding during assembly, and the number of parts required for assembly is small, the assembly steps are few, the reliability is higher, and the raw material cost and the assembly cost of the motor shell can be reduced.

[0046] In the embodiments of the present disclosure, the outer diameter surface of the guide fin 3 is in interference fit with the inner surface of the outer shell 2. In some embodiments, as shown in Figure 1 , the inner shell 1 is provided with a first connecting portion at one end close to the inner end cover portion 12, and the outer shell 2 is provided with a second connecting portion at one end away from the outer end cover portion 22; the first connecting portion and the second connecting portion are fixedly connected by a bolt 6.

[0047] In some embodiments, as shown in Figure 1 , the outer surface of the inner cylindrical portion 11 is provided with a sealing ring 7 at each end.

[0048] Figure 3 is a schematic view of an inner shell in the embodiments of the present disclosure.

[0049] As shown in Figure 1 and Figure 3As shown, the spacing between the ribs 3 on the inner shell 1 decreases in the direction in which the inner diameter of the inner surface of the outer shell 2 increases in the axial direction. In some embodiments, the spacing between the ribs 3 on the inner shell 1 decreases in the direction in which the inner diameter of the inner surface of the outer shell 2 increases, so that the cross-sectional area of the cooling water channel is consistent at different positions. That is, the higher the height of the rib 3, the smaller the spacing between adjacent ribs 3.

[0050] In the embodiments of the present disclosure, the cross-sectional area of the cooling water channel at different positions can be equal or similar, for example, within an error range. The present disclosure does not make special limitations on this.

[0051] In the embodiments of the present disclosure, as shown, Figure 1 the height of the rib 3 increases from right to left, and the cross section of the cooling water channel is trapezoidal. By adjusting the spacing between adjacent ribs 3 at different positions, the cross-sectional area of the cooling water channel is consistent, which can make the flow rate of the cooling liquid in the cooling water channel uniform, thereby improving the temperature rise consistency of the entire motor housing.

[0052] In some embodiments, the wall thickness of the inner shell 1 is consistent, which is conducive to ensuring uniform heat dissipation.

[0053] In the embodiments of the present disclosure, the first water channel 4 and the second water channel 5 can form a standard double helix structure or a non-standard double helix structure. The present disclosure does not make special limitations on this.

[0054] In the embodiments of the present disclosure, one cooling water channel is a non-standard double helix structure composed of a flat water channel and a transition structure.

[0055] As shown, Figure 3 , Figure 4 the rib 3 includes a flow guiding portion 31 and a transition portion 32; the extension direction of the flow guiding portion 31 is perpendicular to the axial direction; the extension direction of the transition portion 32 intersects the circumferential direction; and the two ends of the transition portion 32 are connected with the flow guiding portion 31 respectively.

[0056] In the embodiments of the present disclosure, the flow guiding portions 31 of the plurality of ribs 3 are parallel to each other and perpendicular to the axial direction, which is conducive to simplifying the calculation and ensuring the consistency of the cross-sectional area of the cooling water channel when designing and processing the cooling water channel.

[0057] In the embodiments of the present disclosure, the non-standard double helix structure composed of flat water channels and transition structures is adopted instead of the water channel of the standard double helix structure, which is beneficial to simplify the mold demolding process, increase the bearing strength of the guide ribs 3, and simplify the production and manufacturing process. The transition structures are used for axial transition between adjacent water channels, which can not only reduce the number of split molds, but also reduce the frequency of defects in the production process of the motor housing and improve the yield of the motor housing production.

[0058] The structure of the transition part 32 is not specially limited in the embodiments of the present disclosure.

[0059] As shown in Figure 4 , the extension direction of the transition part 32 is parallel to the axial direction, and the transition part 32 is smoothly connected with the guide part 31.

[0060] Figure 4 As shown in , the transition part 32 is axially perpendicular. In some embodiments, the transition part 32 can also be a smooth transition structure, for example, an axially inclined transition or an arc-shaped transition. The present disclosure does not specially limit this.

[0061] Figure 1 In some embodiments, as shown in Figure 3 , at least one first shunt rib 81 is arranged in the first water channel 4, and the first shunt rib 81 is used to divide the part of the first water channel 4 close to the water inlet into a plurality of first sub-water channels.

[0062] In some embodiments, as shown in Figure 1 and Figure 3 , at least one second shunt rib 82 is arranged in the second water channel 5, and the second shunt rib 82 is used to divide the part of the second water channel 5 close to the water outlet into a plurality of second sub-water channels.

[0063] In the embodiments of the present disclosure, the height of the guide ribs 3 at the water inlet and the water outlet is low, which results in a wide width of the cooling water channel at the water inlet and the water outlet. According to the fluid mechanics water flow cross-section velocity gradient principle and the existence of kinematic viscosity, the flow rate in the middle of the cooling water channel is the fastest and the flow rate at the edge is the slowest. Dividing the part of the first water channel 4 close to the water inlet into a plurality of first sub-water channels and / or dividing the part of the second water channel 5 close to the water outlet into a plurality of second sub-water channels is beneficial to make the flow state and flow rate of the cooling liquid more uniform and prevent the local temperature from being uneven due to the too wide width of the water channel at the water inlet and the water outlet.

[0064] In some embodiments, the water inlet and the water outlet are arranged on opposite sides of the first end; the second water channel 5 includes an expansion part 54 in communication with the water outlet, and at least one third shunt rib 83 is arranged in the expansion part 54.

[0065] In some embodiments, as shown in Figure 3As shown, the plurality of third distribution ribs 83 divide the expansion portion 54 into a plurality of third sub-water channels, and the sum of the cross-sectional areas of the plurality of third sub-water channels is consistent with the cross-sectional area of the cooling water channel.

[0066] In a second aspect, the embodiments of the present disclosure provide an electric machine, comprising an electric machine housing, a stator and a rotor, the stator and the rotor being installed in the electric machine housing, and the electric machine housing being the electric machine housing according to the first aspect of the embodiments of the present disclosure.

[0067] In order for those skilled in the art to more clearly understand the technical solutions provided by the embodiments of the present disclosure, the technical solutions provided by the embodiments of the present disclosure are described in detail below with specific embodiments:

[0068] Embodiments

[0069] Figure 5 Fig. 1 is a schematic diagram of a water channel structure in a counterflow heat exchange form according to an embodiment of the present disclosure. The first water channel 4 is a cold water channel, and the second water channel 5 is a hot water channel.

[0070] According to the counterflow heat exchange principle, the cold water temperature at the water inlet is 20℃, and the cold water temperature difference between the mutually spaced cold water channels is 2℃, so the cold water temperatures in the cold water channel 41, the cold water channel 42 and the cold water channel 43 are 20℃, 22℃ and 24℃, respectively.

[0071] The hot water temperature of the backflow is 26℃, and the hot water temperature difference between the mutually spaced hot water channels is 2℃, so the hot water temperatures in the hot water channel 53, the hot water channel 52 and the hot water channel 51 are 26℃, 28℃ and 30℃, respectively.

[0072] There is always a large temperature difference between adjacent cold water channels and hot water channels, so that the temperature of the electric machine housing is more uniform, and the heat exchange efficiency is high.

[0073] Comparative Example

[0074] Figure 6 Fig. 2 is a schematic diagram of a one-way spiral parallel flow heat exchange water channel.

[0075] The cold water temperature at the water inlet is 20℃, and the cold water temperature difference between adjacent water channels is 2℃, so the water temperatures in the water channels are 20℃, 22℃, 24℃, 26℃, 28℃ and 30℃, respectively.

[0076] The electric machine housing has cold and hot poles, and the heat exchange efficiency is low.

[0077] Example embodiments have been disclosed herein and, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation. In some instances, it will be apparent to those skilled in the art that features, characteristics or / and elements described in connection with a particular embodiment can be used in conjunction with other embodiments unless otherwise explicitly stated. Accordingly, it will be understood that various changes in form and details can be made without departing from the scope of the disclosure as set forth in the appended claims.

Claims

1. An electrical machine housing, characterized in that The motor casing comprises an inner casing and an outer casing; A plurality of flow guide ribs extending in the circumferential direction are arranged on the outer surface of the inner casing, forming a cooling water channel; The first end of the motor casing is provided with a water inlet and a water outlet; the cooling water channel comprises a first water channel and a second water channel; the first water channel is in communication with the water inlet at the first end, and the second water channel is in communication with the water outlet at the first end; the first water channel and the second water channel are in communication at the second end of the motor casing; the first water channel and the second water channel are arranged alternately in the axial direction; The inner surface of the outer casing is a conical surface; in the axial direction, the height of the flow guide rib increases in the direction of increasing inner diameter of the inner surface of the outer casing.

2. The motor housing of claim 1, wherein, The outer diameter surface of the flow guide rib is a conical surface, and the outer diameter surfaces of a plurality of flow guide ribs are on the same conical surface.

3. The motor housing of claim 2, wherein, The taper of the outer diameter surface of the flow guide rib ranges from 0° to 1°.

4. The motor housing of claim 2, wherein, The taper of the outer diameter surface of the flow guide rib is positively correlated with the length of the motor casing in the axial direction.

5. The motor housing of claim 2, wherein, The outer diameter surface of the flow guide rib is in interference fit with the inner surface of the outer casing.

6. The motor housing of claim 1, wherein, In the axial direction, the spacing between the flow guide ribs decreases in the direction of increasing inner diameter of the inner surface of the outer casing.

7. The motor housing of claim 6, wherein, The cross-sectional area of the cooling water channel is consistent at different positions.

8. The motor housing of any one of claims 1 to 7, wherein, The flow guide rib comprises a flow guide part and a transition part; the extension direction of the flow guide part is perpendicular to the axial direction; the extension direction of the transition part intersects the circumferential direction; and the two ends of the transition part are respectively connected with the flow guide part.

9. The motor housing of claim 8, wherein, The extension direction of the transition part is parallel to the axial direction, and the transition part is smoothly connected with the flow guide part.

10. The motor housing of any one of claims 1 to 7, wherein, At least one first flow dividing rib is arranged in the first water channel, and the first flow dividing rib is used to divide the part of the first water channel close to the water inlet into a plurality of first sub-water channels; and / or At least one second flow dividing rib is arranged in the second water channel, and the second flow dividing rib is used to divide the part of the second water channel close to the water outlet into a plurality of second sub-water channels.

11. The motor housing of any one of claims 1 to 7, wherein, The water inlet and the water outlet are arranged on opposite sides of the first end; the second water channel comprises an expansion part in communication with the water outlet, and at least one third flow dividing rib is arranged in the expansion part.

12. The motor housing of claim 11, wherein, The plurality of third flow dividing ribs divide the expansion part into a plurality of third sub-water channels, and the sum of the cross-sectional areas of the plurality of third sub-water channels is consistent with the cross-sectional area of the cooling water channel.

13. The motor housing of any one of claims 1 to 7, wherein, The inner casing comprises an inner cylindrical part and an inner end cover part arranged at one end of the inner cylindrical part, and the inner cylindrical part and the inner end cover part are in an integrated structure; The outer casing comprises an outer cylindrical part and an outer end cover part arranged at one end of the outer cylindrical part, and the outer cylindrical part and the outer end cover part are in an integrated structure; The inner end cover part and the outer end cover part are located at opposite ends of the motor casing.

14. The motor housing of claim 13, wherein, A first connecting part is arranged at one end of the inner casing close to the inner end cover part, and a second connecting part is arranged at one end of the outer casing away from the outer end cover part; the first connecting part and the second connecting part are fixedly connected by bolts.

15. The motor housing of claim 13, wherein, Sealing rings are respectively arranged at both ends of the outer surface of the inner cylindrical part.

16. An electric machine comprising a machine housing, a stator, a rotor, said stator, said rotor being mounted in said machine housing, characterized in that, The motor casing is the motor casing according to any one of claims 1 to 15.

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