Motor

Abstract

The utility model provides a motor, the motor comprises a housing (100) and a stator (200) accommodated in the housing (100), the stator (200) comprises a stator iron core (210) fixed on the housing (100) and a stator winding (220) attached to the stator iron core (210), the stator iron core (210) is provided with a plurality of winding grooves (214) extending along the axial direction and a circumferential channel (216) extending along the circumferential direction, and the stator winding (220) is arranged in the stator iron core (210). The shell (100) is provided with a liquid inlet hole (116), the liquid inlet hole (116) extends and penetrates through the shell (100) and is communicated with the circumferential channel (216), each winding groove (214) accommodates a plurality of wires of the stator winding (220) and forms an axial channel (217) which extends and penetrates through the stator iron core (210) in the axial direction, the circumferential channel (216) intersects with each axial channel (217), and the liquid inlet hole (116) is communicated with the circumferential channel (216). And each axial channel (217) is divided into two sections which are axially positioned on two sides of the circumferential channel (216).

Description

Technical Field

[0001] The present disclosure relates to the field of electric motors, and more particularly, to an electric motor with an improved liquid cooling design. Background Art

[0002] With the rapid development of electric motors, their power density and lightweight design are attracting increasing attention. However, heat dissipation has become a major constraint to further improving their power density. Taking a common permanent magnet synchronous motor as an example, when an alternating current is passed through the stator windings, a rotating magnetic field is generated. This rotating magnetic field couples with the permanent magnets on the rotor, driving the rotor to rotate. However, this rotating magnetic field also induces eddy currents in the rotor and stator cores, causing them to heat up. The alternating current also heats the stator windings, generating the most heat and being the most difficult to dissipate. To increase the power of the motor, a higher alternating current is required to pass through the stator windings, but this also increases the heat generated by the stator core, stator windings, and rotor core. If this heat cannot be effectively dissipated, the motor's service life may be shortened or even cause overheating and burnout. In the existing technology, there are many liquid cooling solutions to help motors dissipate heat, including placing the stator core in a water jacket, machining cooling liquid channels in the stator core, etc. However, these liquid cooling solutions all have problems such as poor manufacturing feasibility, uneven heat absorption, and high manufacturing costs to a certain extent.

[0003] Therefore, in this field, there is an urgent need for a technical solution that can help the motor dissipate heat effectively and has high manufacturing feasibility. Utility Model Content

[0004] In order to solve the above-mentioned problems in the prior art, the present disclosure proposes an improved motor, which includes a housing and a stator accommodated in the housing, wherein the stator includes a stator core fixed to the housing and a stator winding attached to the stator core, and the stator core is provided with a plurality of winding slots extending in the axial direction and a circumferential channel extending in the circumferential direction, wherein the housing is provided with a liquid inlet hole, which extends through the housing and is connected to the circumferential channel, each winding slot accommodates a plurality of wires of the stator winding, and forms an axial channel extending axially through the stator core, and wherein the circumferential channel intersects with each axial channel and divides each axial channel into two sections axially located on both sides of the circumferential channel.

[0005] According to an optional embodiment of the present disclosure, the circumferential channel is positioned axially centrally in the stator core.

[0006] According to an optional embodiment of the present disclosure, the circumferential channel extends through the entire circumference and is radially defined between an outer boundary and an inner boundary, wherein the outer boundary is located radially outside each winding slot and the inner boundary is located radially inside each winding slot.

[0007] According to an optional embodiment of the present disclosure, the stator core has an annular portion defined between its radial outer surface and the outer boundary, and is provided with a radial channel extending through the annular portion, wherein the radial channel connects the circumferential channel with the liquid inlet hole.

[0008] According to an optional embodiment of the present disclosure, the outer boundary is aligned with a radially outer surface of the stator core, so that the circumferential channel opens on the radially outer surface.

[0009] According to an optional embodiment of the present disclosure, the stator core has an annular portion defined between a radial inner surface thereof and the inner boundary.

[0010] According to an optional embodiment of the present disclosure, the inner boundary is aligned with a radial inner surface of the stator core, so that the circumferential channel opens on the radial inner surface.

[0011] According to an optional embodiment of the present disclosure, the outer boundary is aligned with the radial outer surface of the stator core, so that the circumferential channel divides the stator core into two parts axially located on both sides of the circumferential channel.

[0012] According to an optional embodiment of the present disclosure, the axial channel is formed by a gap around the wire in each winding slot.

[0013] According to an optional embodiment of the present disclosure, multiple wires in each winding slot are stacked together radially, and at least one of the multiple wires is a special-shaped wire, which is provided with a groove recessed from its surface, and the axial channel is formed by the groove of each special-shaped wire.

[0014] According to an optional embodiment of the present disclosure, each of the plurality of wires is the special-shaped wire.

[0015] According to an optional embodiment of the present disclosure, the groove is formed on one of the two radially opposite surfaces of the special-shaped wire, and the thickness of the special-shaped wire on one side of the groove is less than the thickness on the other side of the groove, so as to form an opening leading to the groove on the side of the special-shaped wire, and the opening connects the circumferential channel with the groove.

[0016] According to an optional embodiment of the present disclosure, the groove is formed on one of two surfaces of the special-shaped wire that are opposite to each other in a tangential direction, so that the groove is connected to the circumferential channel.

[0017] According to an optional embodiment of the present disclosure, the shell internally defines two liquid collecting cavities located axially on both sides of the stator core, wherein each axial channel leads to the two liquid collecting cavities at two axially separated ends of the stator core.

[0018] According to an optional embodiment of the present disclosure, the stator winding has two winding heads located on both sides of the stator core in the axial direction, wherein each winding head is accommodated in one of the two liquid collecting cavities.

[0019] According to an optional embodiment of the present disclosure, the shell is further provided with two drainage holes, wherein each drainage hole extends through the shell and is communicated with one of the two liquid collecting chambers.

[0020] According to an optional embodiment of the present disclosure, the motor further includes a rotor located radially inward of the stator and an isolation cylinder disposed between the stator and the rotor.

[0021] The present disclosure can be embodied as the illustrative embodiments in the accompanying drawings. However, it should be noted that the drawings are only illustrative and any changes conceived under the teachings of the present disclosure should be considered to be included within the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings illustrate exemplary embodiments of the present disclosure. These drawings should not be interpreted as necessarily limiting the scope of the present disclosure, wherein:

[0023] Figure 1 is a schematic cross-sectional view of a motor according to an embodiment of the present disclosure;

[0024] Figure 2 yes Figure 1 A schematic perspective view of the stator core of the motor shown;

[0025] Figure 3 It is along Figure 1 A schematic cross-sectional view of the stator core of the motor taken along line III-III in FIG. 1 , wherein the circumferential channels are illustrated with special hatching for clarity;

[0026] Figure 4 yes Figure 2 A schematic front view of a stator lamination of a stator core is shown;

[0027] Figure 5 yes Figure 2 A schematic front view of the guide laminations of the stator core is shown; and

[0028] Figure 6 It is along Figure 1 Schematic cross-sectional view of a portion of the stator of the motor taken along line VI-VI in FIG. DETAILED DESCRIPTION

[0029] Further features and advantages of the present disclosure will become more apparent from the following description with reference to the accompanying drawings. Exemplary embodiments of the present disclosure are shown in the accompanying drawings, and the drawings are not necessarily drawn to scale. However, the present disclosure may be implemented in many different forms and should not be construed as necessarily limited to the exemplary embodiments disclosed herein. Rather, these exemplary embodiments are provided solely to illustrate the present disclosure and to convey the spirit and substance of the present disclosure to those skilled in the art.

[0030] The present disclosure aims to propose a motor with an improved liquid cooling design. The liquid cooling design according to the present disclosure allows the coolant to directly contact the stator winding wire in each winding slot of the stator core, so that the coolant can directly cool the stator winding wire in each winding slot (referred to as in-slot direct cooling), thereby achieving efficient heat dissipation of the stator winding. In particular, the liquid cooling design according to the present disclosure can also improve the uniformity of the temperature distribution of the stator core and the stator winding in the axial direction, and improve the uniformity of the coolant pressure distribution in each winding slot, which not only helps to efficiently cool the stator winding wire over the entire length of each winding slot, but also reduces the pressure required to drive the coolant to flow in each winding slot, so as to reduce the performance requirements of supporting facilities such as hydraulic pumps, thereby reducing the configuration cost of the cooling design according to the present disclosure. In addition, the liquid cooling design according to the present disclosure also has high manufacturing feasibility, so while helping the motor to achieve effective heat dissipation, it will not significantly increase the manufacturing cost of the motor.

[0031] Various optional but non-limiting embodiments of the motor according to the present disclosure are described in detail below with reference to the accompanying drawings. As used herein, the term "axial" refers to a direction parallel to or defined by the motor's axis of rotation; "radial" refers to a direction perpendicular to the motor's axis of rotation; "circumferential" refers to a direction surrounding the motor's axis of rotation; and "tangential" refers to a direction tangential to any circle whose center falls on the axis of rotation, so "tangential" is also perpendicular to "radial". Unless otherwise expressly stated herein, these and other terms indicating directions have their usual meanings in the art.

[0032] refer to Figure 1 , which shows a schematic cross-sectional view of a motor according to an embodiment of the present disclosure. Figure 1As shown, the motor 10 generally includes a housing 100, a stator 200 fixedly disposed in the housing 100, a rotor 300 adapted to be coupled to the stator 200 through magnetic flux, and a main shaft 400 rotatably supporting the rotor 300 in the housing 100, wherein the stator 200 is disposed radially outside the rotor 300 and generally includes a stator core 210 fixed to the housing 100 and a stator winding 220 attached to the stator core 210, the rotor 300 generally includes a rotor core 310 fixed to the main shaft 400 and a plurality of permanent magnets 320 attached to the rotor core 310, and the main shaft 400 is oriented along the rotation axis XX' so that the main shaft 400 can rotate around the rotation axis XX' together with the rotor 300 under the drive of the rotor 300. Figure 1 In the illustrated embodiment, the motor 10 is configured as a permanent magnet synchronous type motor. During operation, an alternating current is passed through the stator winding 220, thereby generating a rotating magnetic field rotating around the rotation axis XX'. Under the guidance of the stator core 210, the rotating magnetic field is coupled with the multiple permanent magnets 320 on the rotor core 310 through magnetic flux, thereby driving the multiple permanent magnets 320 and the rotor core 310 connected thereto to rotate around the rotation axis XX'. The rotor core 310 in turn drives the main shaft 400 to rotate around the rotation axis XX', thereby realizing the conversion of electrical energy into mechanical energy.

[0033] refer to Figure 2 , which shows Figure 1 Schematic three-dimensional diagram of the stator core of the motor shown. Figure 1 and Figure 2As shown, the stator core 210 is generally cylindrical and has two axial surfaces 211 spaced apart from or opposite to each other along the axial direction and two radial surfaces 212, 213 spaced apart from or opposite to each other along the radial direction. The two radial surfaces 212, 213 are composed of a radial inner surface 212 close to or facing the rotor 300 and a radial outer surface 213 away from or facing away from the rotor 300. The two axial surfaces 211 are generally plane, and the two radial surfaces 212, 213 are generally cylindrical surfaces. The stator core 210 is fixed to the housing 100 so that its radial outer surface 213 fits or abuts against the inner surface 101 of the housing 100. In addition, the stator core 210 is provided with a plurality of winding slots 214 on its radial inner side. These winding slots 214 are evenly distributed along the circumferential direction, and each winding slot 214 extends along the axial direction from one axial surface 211 of the stator core 210 to the other axial surface 211, so that each winding slot 214 extends through the stator core 210 in the axial direction and is open on each axial surface 211 of the stator core 210. In particular, the stator core 210 is further provided with a plurality of pole shoe gaps 215 on its radial inner side. These pole shoe gaps 215 are also evenly distributed along the circumferential direction, and each pole shoe gap 215 extends along the axial direction from one axial surface 211 of the stator core 210 to the other axial surface 211, so that each pole shoe gap 215 extends through the stator core 210 in the axial direction and is open on each axial surface 211 of the stator core 210. In addition, each pole shoe gap 215 is also open on the radial inner surface 212 of the stator core 210, so that the radial inner surface 212 is divided into a plurality of segments distributed along the circumferential direction by the plurality of pole shoe gaps 215, and each pole shoe gap 215 is located radially inward of a winding slot 214, so that each winding slot 214 leads to the radial inner surface 212 of the stator core 210 through the corresponding pole shoe gap 215. In this configuration, each winding slot 214 is configured as a semi-open slot (also referred to as a semi-closed slot). Of course, the above configuration is merely exemplary. In an embodiment not shown, the stator core 210 may also not have any pole shoe gaps 215, so that the radial inner surface 212 extends continuously along the circumferential direction or continuously extends across the entire circumference. In this configuration, the winding slots 214 are configured as fully closed slots.

[0034] Back to Figure 1The stator winding 220 is actually composed of a large number of wires. A plurality of wires of the stator winding 220 are provided in each winding slot 214 of the stator core 210. The stator winding 220 is attached to the stator core 210 in this manner, and these wires are arranged to pass through the winding slots 214 in the axial direction and are connected to each other in a specific manner outside the stator core 210, thereby forming a winding head 221 located outside the stator core 210 (more specifically, axially outside). Figure 1 In the illustrated embodiment, the stator winding 220 has two winding heads 221 located on both axial sides of the stator core 210. The stator winding 220 can receive alternating current from an external power supply circuit through the winding heads 221, and the specific connection method of the wires in the winding heads 221 enables the wires in each winding slot 214 to generate a desired rotating magnetic field, thereby converting electrical energy into mechanical energy as described above. However, as a byproduct of mechanical energy, eddy currents are generated in the stator core 210 and the rotor core 310 due to the rotating magnetic field, and due to the resistance of the stator winding 220 itself, the stator core 210, the rotor core 310 and the stator winding 220 all generate heat, and among them, the stator winding 220 generates the most heat and is the most difficult to dissipate. The heat dissipation problem of the stator winding 220 is one of the main factors limiting the service life and performance improvement of the motor.

[0035] In order to achieve effective heat dissipation of the stator winding 220, the motor 10 has an improved liquid cooling design. Figure 1-Figure 3 ,in Figure 3 Shown along Figure 1 Schematic cross-sectional view of the stator core of the motor taken along line III-III. Figure 1-Figure 3As shown, the stator core 210 is internally provided with a generally annular circumferential channel 216 (also referred to as a circumferential channel) that extends continuously in the circumferential direction or extends through the entire circumference. The circumferential channel 216 intersects with each winding slot 214 so that each winding slot 214 is fluidically connected to the circumferential channel 216. In other words, the circumferential channel 216 divides each winding slot 214 into two sections located on both sides of the circumferential channel 216 along the axial direction, and each section is fluidically connected to the circumferential channel 216. Specifically, each winding slot 214 includes a space not occupied by the wires of the stator winding 220. This space forms an axial channel 217 in the winding slot 214 that extends axially through the stator core 210. Specifically, the axial channel 217 in each winding slot 214 extends axially from one axial surface 211 of the stator core 210 to the other axial surface 211. A circumferential channel 216 intersects the axial channel 217 in each winding slot 214, thereby providing fluid communication therewith. Specifically, the circumferential channel 216 divides each axial channel 217 into two sections located axially on either side of the circumferential channel 216, each of which is in fluid communication with the circumferential channel 216. Furthermore, the housing 100 is further provided with a liquid inlet 116 that extends through the housing 100 and is in fluid communication with the circumferential channel 216.

[0036] Under the above configuration, the coolant from the outside of the housing 100 of the motor 10 (for example, a cooling pump) can enter the interior of the housing 100 through the liquid inlet hole 116 and be transported to the circumferential channel 216. The coolant entering the circumferential channel 216 will flow in the circumferential channel 216 along the circumferential direction and thus be distributed over the entire circumferential direction or the entire circumference. Furthermore, since the circumferential channel 216 is fluidically connected to each axial channel 217, the coolant will flow from the circumferential channel 216 to each axial channel 217 and flow along the axial channel 217 to the two axial surfaces 211 of the stator core 210, thereby enabling the coolant to directly contact the wire of the stator winding 220 in each axial channel 217, thereby realizing direct cooling in the slot of the stator winding 220. Furthermore, in this configuration, the wire in each winding slot 214 extends axially through the circumferential channel 216, so that each wire absorbs heat from the surrounding coolant in the circumferential channel 216, further improving heat dissipation from the stator winding 220. It is also worth noting that the above configuration defines a flow path that allows coolant to flow from the middle of each axial channel 217 and out of both ends. Compared to a flow path that allows coolant to flow from one end to the other of each axial channel 217, this configuration can improve the pressure and temperature distribution in each axial channel 217 and reduce the pressure required to drive the coolant flow, thereby lowering the performance requirements for supporting facilities such as hydraulic pumps.

[0037] In particular, if Figure 1 As shown, the circumferential channel 216 is centrally located in the axial direction in the stator core 210, so that the portions of each axial channel 217 on both sides of the circumferential channel 216 have substantially equal lengths. With this configuration, the pressure distribution and temperature distribution in each axial channel 217 can be further improved, and the pressure required to drive the coolant flow can be further reduced.

[0038] In particular, if Figure 1-Figure 3As shown, the circumferential channel 216 extends radially inward from its outer boundary 216a to its inner boundary 216b. That is, the circumferential channel 216 is defined radially between the outer boundary 216a and the inner boundary 216b. The outer boundary 216a is radially outside each winding slot 214, and the inner boundary 216b is radially inside each winding slot 214, so that the circumferential channel 216 extends radially across each winding slot 214. In this configuration, before the wire is set in the winding slot 214, each winding slot 214 is in fluid communication with the circumferential channel 216 over its entire cross-section. This ensures that after the wire is set in the winding slot 214, each axial channel 217 is in fluid communication with the circumferential channel 216 over its entire cross-section. This allows coolant to flow smoothly from the circumferential channel 216 to each axial channel 217, thereby improving in-slot direct cooling of the stator winding 220.

[0039] More specifically, if Figure 1-Figure 3 As shown, the outer boundary 216a of the circumferential channel 216 is located radially inward of the radial outer surface 213 of the stator core 210. That is, the outer boundary 216a is radially spaced apart from the radial outer surface 213, so that an annular portion 219 of the stator core 210 is defined between the outer boundary 216a and the radial outer surface 213. In addition, the stator core 210 is provided with a radial channel 218 extending radially from the radial outer surface 213 thereof through the annular portion 219 to the outer boundary 216a of the circumferential channel 216. The stator core 210 is positioned within the housing 100 such that the radial channel 218 is aligned with or aligned with the liquid inlet hole 116, so that the radial channel 218 can fluidically connect the liquid inlet hole 116 with the circumferential channel 216. In this configuration, the coolant from the liquid inlet hole 116 can be transported to the circumferential channel 216 through the radial channel 218 and then distributed to each axial channel 217 through the circumferential channel 216 to achieve direct cooling in the slots of the stator winding 220 .

[0040] More specifically, if Figure 1-Figure 3 As shown, the circumferential channel 216 extends radially inward to the radial inner surface 212 of the stator core 210, such that the inner boundary 216b of the circumferential channel 216 is aligned with the radial inner surface 212 of the stator core 210. In this configuration, the circumferential channel 216 opens to the radial inner surface 212 of the stator core 210. In other words, the circumferential channel 216 opens on the radial inner surface 212 of the stator core 210, thereby reducing the difficulty of disposing the circumferential channel 216 and thus reducing the configuration cost of the liquid cooling design of the motor 10.

[0041] It should be pointed out that Figure 1-Figure 3The illustrated embodiment is merely exemplary. In one embodiment, not shown, the circumferential channel 216 extends radially outward to the radially outer surface 213 of the stator core 210, such that the outer boundary 216a of the circumferential channel 216 is aligned with the radially outer surface 213 of the stator core 210. In this configuration, the circumferential channel 216 opens onto the radially outer surface 213 of the stator core 210. That is, the circumferential channel 216 opens onto the radially outer surface 213 of the stator core 210, which allows the circumferential channel 216 to be directly fluidically connected to the liquid inlet 116 without the need for the radial channel 218. In one embodiment, not shown, the inner boundary 216b of the circumferential channel 216 is radially outward of the radially inner surface 212 of the stator core 210. That is, the inner boundary 216b is radially spaced apart from the radially inner surface 212, such that an annular portion of the stator core 210 is defined between the inner boundary 216b and the radially inner surface 212. In this configuration, the annular portion prevents the coolant in the circumferential channel 216 from flowing radially inwardly of the stator core 210, thereby preventing the coolant from increasing the rotational resistance of the rotor 300. In one embodiment (not shown), the circumferential channel 216 extends radially from the radially outer surface 213 of the stator core 210 to the radially inner surface 212 thereof, such that the outer boundary 216a and the inner boundary 216b of the circumferential channel 216 are aligned with the radially outer surface 213 and the radially inner surface 212 of the stator core 210, respectively. In this configuration, the circumferential channel 216 opens to both the radially outer surface 213 and the radially inner surface 212 of the stator core 210, thereby dividing the stator core 210 into two portions located on either side thereof in the axial direction. This minimizes the difficulty of disposing the circumferential channel 216 and reduces the configuration cost of the liquid cooling design of the motor 10.

[0042] Back to Figure 2 The stator core 210 includes a generally cylindrical stator yoke 210a and a plurality of stator teeth 210b that protrude radially inward from the stator yoke 210a and are evenly distributed along the circumferential direction. The axial surface 211 of the stator core 210 is formed by the axial surfaces of the stator yoke 210a and the plurality of stator teeth 210b. The radially outer surface 213 of the stator core 210 is formed by the radially outer surface of the stator yoke 210a. The radially inner surface 212 of the stator core 210 is formed by the radially inner surfaces of the plurality of stator teeth 210b. Furthermore, each winding slot 214 is defined between two adjacent stator teeth 210b. Each stator tooth 210b is provided with a pole shoe 210c at its end, and each pole shoe gap 215 is defined between two adjacent pole shoes 210c. In particular, the stator core 210 includes a plurality of stator laminations 510 and one guide lamination 520 stacked together in the axial direction, wherein the guide lamination 520 is located between two stator laminations 510 .

[0043] refer to Figure 4 and Figure 5 ,in, Figure 4 Shown Figure 2 A schematic front view of the stator laminations of the stator core shown, Figure 5 Shown Figure 2 Schematic front view of the guide laminations of the stator core shown. Figure 4 As shown, the stator lamination 510 includes a generally annular stator yoke 511 and a plurality of stator fins 512 that protrude radially inward from the stator yoke 511 and are evenly distributed along the circumferential direction. The stator yoke 511 of each stator lamination 510 is intended to be aligned with one another in the axial direction to form the stator yoke 210a of the stator core 210, and the stator fins 512 of each stator lamination 510 are intended to be aligned with one another in the axial direction to form the stator teeth 210b of the stator core 210. In particular, a pole shoe 513 is further formed at the end of each stator fin 512. The pole shoe 513 of each stator lamination 510 is intended to be aligned with one another in the axial direction to form the pole shoe 210c of the stator core 210. In this configuration, the stator lamination 510 has an outer surface 514 and an inner surface 515 that are opposite or opposed to each other in the radial direction, and the outer surface 514 is composed of the outer surface of the stator yoke plate 511, while the inner surface 515 is composed of the inner surfaces of multiple pole shoe plates 513.

[0044] like Figure 5 As shown, the guide lamination 520 is generally annular and has an outer surface 521 and an inner surface 522 that are opposite or opposed to each other in the radial direction. The outer surface 521 is intended to be aligned with the outer surface 514 of the stator lamination 510, so that the outer surface 521 and the outer surface 514 of each stator lamination 510 together constitute the radial outer surface 213 of the stator core 210, while the inner surface 522 is intended to constitute the outer boundary 216a of the circumferential channel 216. In addition, the guide lamination 520 is further provided with a groove 523 that is recessed from its axial end surface and extends from the outer surface 521 to the inner surface 522. The groove 523 is intended to form the radial channel 218. Of course, under this configuration of the guide laminations 510, the inner boundary 216b of the circumferential channel 216 is defined by the radial inner surface 212 of the stator core 210, and the radial inner surface 212 of the stator core 210 is composed of the inner surface 515 of each stator lamination 210, and the circumferential channel 216 is defined in the axial direction between the two stator laminations 510 adjacent to the guide laminations 520.

[0045] The above is with the help of Figure 2-Figure 5While an exemplary manufacturing method for the stator core 210 has been described, it will be understood by those skilled in the art that the stator core 210 can obviously be manufactured by other methods, such as additive manufacturing processes such as 3D printing and powder sintering. After the stator core 210 is manufactured, if the stator winding 220 is composed of round conductors, a winding machine is required to insert the round conductors into each winding slot 214 and wind them around each stator tooth 210b. Due to structural interference, the volume ratio of the conductor in each winding slot 214 (also known as the slot fill ratio) is relatively small (generally less than 40%). Therefore, the gaps around the conductor in each winding slot 214 can form an axial channel 217. If the stator winding 220 is composed of flat conductors, the flat conductors only need to be inserted into each winding slot 214 along the axial direction without being wound around each stator tooth 210b. Therefore, a higher slot fill ratio can be achieved, but the slot fill ratio still cannot reach 100%. Therefore, the gaps around the conductor in each winding slot 214 can still form an axial channel 217. Of course, compared with the axial channel 217 of the round wire motor, the cross section of the axial channel 217 of the flat wire motor is smaller due to the higher slot fill rate, which may cause the flow of the coolant to be blocked.

[0046] In order to increase the cross section of the axial channel 217 of the flat wire motor, refer to Figure 6 , which shows the Figure 1 Schematic cross-sectional view of a portion of the stator of the motor taken along line VI-VI in FIG. Figure 6 As shown, each winding slot 214 is provided with a plurality of conductors (U-shaped conductors, X-shaped conductors or I-shaped conductors, etc.) of the stator winding 220. These conductors are stacked together in the radial direction in the winding slot 214 and are interconnected in a specific manner at the winding head 221 so that the stator winding 220 can generate the desired rotating magnetic field when an alternating current is passed through it. In particular, at least one of the plurality of conductors in each winding slot 214 is a special-shaped conductor 222, which is provided with a groove 223 recessed from its surface and is arranged so that the groove 223 extends through the stator core 210 in the axial direction. Under this configuration, the groove 223 can constitute a part of the axial channel 217. In other words, the axial channel 217 can be formed by the groove 223 of each special-shaped conductor 222, thereby increasing the cross-section of the axial channel 217 so that the coolant can flow through the axial channel 217 more smoothly. In particular, in Figure 6 In the illustrated embodiment, each of the plurality of wires in each winding slot 214 is a special-shaped wire 222 .

[0047] Specifically, groove 223 is formed on one of two radially opposite or facing surfaces of shaped conductor 222, and the thickness of shaped conductor 222 on one side of groove 223 (the left side in the figure) is less than the thickness on the other side of groove 223 (the right side in the figure), thereby forming an opening 224 leading to groove 223 on that side. In this configuration, groove 223 can be fluidically connected to circumferential channel 216 via opening 224 on the side of shaped conductor 222, allowing coolant in circumferential channel 216 to flow into groove 223 through opening 224 and then flow along groove 223 toward both ends of stator core 210, directly cooling shaped conductor 222 and adjacent conductors. In an embodiment not shown, groove 223 can also be formed on one of two circumferentially or tangentially opposite surfaces of shaped conductor 222. In this configuration, the groove 223 can be directly in fluid communication with the circumferential channel 216 , so that the coolant in the circumferential channel 216 can flow directly into the groove 223 without providing an opening 224 on the side of the special-shaped wire 222 .

[0048] After the coolant flows along the axial channel 217 in each winding slot 214 (e.g., the groove 223 of each special-shaped conductor 222) toward both ends of the stator core 210 and flows out from both ends of the stator core 210, the coolant will be collected inside the housing 100. Figure 1 As described above, the housing 100 internally defines two liquid collection chambers 100c located on either side of the stator core 210 along the axial direction. The winding heads 221 of the stator winding 220 can be accommodated in the liquid collection chambers 100c. In this configuration, the axial channel 217 in each winding slot 214 leads to the two liquid collection chambers 100c at the two axially separated ends of the stator core 210. This allows the coolant discharged from the two ends of each axial channel 217 to be collected in the two liquid collection chambers 100c. The coolant collected in the liquid collection chambers 100c can directly contact the winding heads 221, thereby helping to dissipate heat from the winding heads 221, thereby further improving the heat dissipation of the stator winding 220.

[0049] In particular, if Figure 1 As shown, the housing 100 may also be provided with two drain holes 118, wherein each drain hole 118 extends through the housing 100 and is in fluid communication with one of the two plenum chambers 100c. In this configuration, coolant from an external source (e.g., a cooling pump) may be delivered to the circumferential channel 216 through the inlet hole 116. The coolant is then distributed by the circumferential channel 216 to the axial channel 217 in each winding slot 214, thereby directly cooling the wires of the stator winding 220 in the axial channel 217. The coolant is then discharged into the two plenum chambers 100c and finally discharged from the motor 10 through the two drain holes 118.

[0050] In particular, if Figure 1 As shown, the motor 10 further includes a generally cylindrical separator 500 disposed within the housing 100. The separator 500 is positioned between the stator 200 and the rotor 300, and its axially spaced ends are connected to the housing 100, thereby fluidically isolating each plenum 100c from the rotor 300. In this configuration, the separator 500, together with the housing 100 and the stator 200, defines each plenum 100c as an annular chamber located radially outward from the rotor 300 and fluidically isolated from the rotor 300. Therefore, in this configuration, coolant in the circumferential channel 216, the axial channel 217, and the plenum 100c can be reliably prevented from contacting the rotor 300, thereby preventing the coolant from increasing the rotational resistance of the rotor 300. Of course, the above embodiment is merely exemplary. In an unillustrated embodiment, the axially separated ends of the insulating cylinder 500 may be located on opposite sides of the stator core 210 but not connected to the housing 100. In other words, the axially separated ends of the insulating cylinder 500 are spaced apart from the housing 100. In this configuration, the insulating cylinder 500 still prevents coolant from entering the air gap between the stator core 210 and the rotor core 310, but allows coolant to contact the main shaft 400, thereby promoting heat dissipation from the main shaft 400 and, through the main shaft 400, from the rotor core 310. In other unillustrated embodiments, as an alternative to the insulating cylinder 500, a sealing wedge may be inserted axially into each pole shoe gap 215 of the stator core 210. The sealing wedge has a shape complementary to the pole shoe gap 215 and extends axially along the entire length of the stator core 210, thereby preventing coolant from entering the air gap between the stator core 210 and the rotor core 310.

[0051] The above describes in detail, with the aid of the accompanying drawings, an optional but non-limiting embodiment of a motor according to the present disclosure. It will be apparent to those skilled in the art that modifications and additions to the techniques and structures, as well as the re-combination of features in the various embodiments, without departing from the spirit and substance of the present disclosure, are all within the scope of the present disclosure. Therefore, such modifications and additions as can be envisioned in light of the teachings of the present disclosure are considered part of the present disclosure. The scope of the present disclosure includes both known equivalent technologies as of the filing date of this disclosure and unforeseen equivalent technologies.

Claims

1. A motor, characterized in that It comprises a housing (100) and a stator (200) accommodated in the housing (100), The stator (200) comprises a stator core (210) fixed to the housing (100) and a stator winding (220) attached to the stator core (210); the stator core (210) is provided with a plurality of winding slots (214) extending in an axial direction and a circumferential channel (216) extending in a circumferential direction. The housing (100) is provided with a liquid inlet (116), the liquid inlet (116) extending through the housing (100) and communicating with the circumferential channel (216), each winding slot (214) accommodating a plurality of wires of the stator winding (220), and forming an axial channel (217) extending axially through the stator core (210), and The circumferential channel (216) intersects with each axial channel (217) and divides each axial channel (217) into two sections located on both sides of the circumferential channel (216) in the axial direction.

2. The motor according to claim 1, characterized in that The circumferential channel (216) is axially centrally located in the stator core (210).

3. The motor according to claim 1, characterized in that The circumferential channel (216) extends through the entire circumference and is radially defined between an outer boundary (216a) and an inner boundary (216b), wherein the outer boundary (216a) is located radially outside each winding slot (214) and the inner boundary (216b) is located radially inside each winding slot (214).

4. The motor according to claim 3, characterized in that The stator core (210) has an annular portion (219) defined between its radial outer surface (213) and the outer boundary (216a), and is provided with a radial channel (218) extending through the annular portion (219), wherein the radial channel (218) connects the circumferential channel (216) with the liquid inlet hole (116).

5. The motor according to claim 3, characterized in that The outer boundary (216a) is aligned with the radial outer surface (213) of the stator core (210) so that the circumferential channel (216) opens on the radial outer surface (213).

6. The motor according to claim 3, characterized in that The stator core (210) has an annular portion defined between its radial inner surface (212) and the inner boundary (216b).

7. The motor according to claim 3, characterized in that The inner boundary (216b) is aligned with the radial inner surface (212) of the stator core (210) such that the circumferential channel (216) opens on the radial inner surface (212).

8. The motor according to claim 7, characterized in that The outer boundary (216a) is aligned with the radial outer surface (213) of the stator core (210) so that the circumferential channel (216) divides the stator core (210) into two parts located axially on either side of the circumferential channel (216).

9. The motor according to any one of claims 1 to 8, characterized in that The axial channel (217) is formed by the space around the wire in each winding slot (214).

10. The motor according to any one of claims 1 to 8, characterized in that Multiple wires in each winding groove (214) are stacked together in the radial direction, and at least one of the multiple wires is a special-shaped wire (222). The special-shaped wire (222) is provided with a groove (223) recessed from its surface, and the axial channel (217) is formed by the groove (223) of each special-shaped wire (222).

11. The motor according to claim 10, characterized in that Each of the plurality of wires is the special-shaped wire (222).

12. The motor according to claim 10, characterized in that The groove (223) is formed on one of two radially opposite surfaces of the special-shaped wire (222), and the thickness of the special-shaped wire (222) on one side of the groove (223) is smaller than the thickness on the other side of the groove (223), so as to form an opening (224) leading to the groove (223) on the side of the special-shaped wire (222), and the opening (224) connects the circumferential channel (216) with the groove (223).

13. The motor according to claim 10, characterized in that The groove (223) is formed on one of two surfaces of the special-shaped wire (222) that are opposite to each other in a tangential direction, so that the groove (223) is communicated with the circumferential channel (216).

14. The motor according to any one of claims 1 to 8, characterized in that The housing (100) internally defines two liquid collecting chambers (100c) located axially on both sides of the stator core (210), wherein each axial channel (217) leads to the two liquid collecting chambers (100c) at two axially separated ends of the stator core (210).

15. The motor according to claim 14, characterized in that The stator winding (220) has two winding heads (221) located on both sides of the stator core (210) in the axial direction, wherein each winding head (221) is accommodated in one of the two liquid collecting chambers (100c).

16. The motor according to claim 14, characterized in that The housing (100) is further provided with two drainage holes (118), wherein each drainage hole (118) extends through the housing (100) and communicates with one of the two liquid collecting chambers (100c).

17. The motor according to any one of claims 1 to 8, characterized in that The motor (10) further includes a rotor (300) located radially inside the stator (200) and an isolation cylinder (500) disposed between the stator (200) and the rotor (300).

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