Stator core for cooling winding end, motor, powertrain, and electric vehicle

Abstract

The present application provides a stator core for cooling a winding end, a motor, a powertrain, and an electric vehicle. The stator core comprises a plurality of stator laminations, and the plurality of stator laminations are sequentially arranged adjacently in the axial direction of the stator core to form at least part of the stator core. Each stator lamination comprises a central hole and a plurality of cooling holes, and the cooling holes are arranged at intervals between the central hole and the outer peripheral surface of the stator lamination. The plurality of stator laminations comprise a first lamination and a second lamination arranged adjacent to each other, and each cooling hole of the first lamination is used for being communicated with one cooling hole of the second lamination and used for cooling a stator winding end so as to form a channel for a cooling medium to flow. In at least one direction of the radial direction or the circumferential direction of the stator core, each cooling hole of the first lamination is eccentrically arranged relative to one corresponding cooling hole of the second lamination communicated with the cooling hole of the first lamination. The stator core can reduce the cross-section of the channel for the cooling medium to flow and improve the flow speed of the cooling medium.

Description

Stator cores, motors, powertrains, and electric vehicles for cooling winding ends

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of the People's Republic of China on January 12, 2024, with application number 202420095315.8 and application name "Stator core, motor, powertrain and electric vehicle for cooling winding ends", the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the technical field of motors, and in particular to a stator core, a motor, a powertrain, and an electric vehicle for cooling winding ends. Background Art

[0004] With the development of technology, the power density of motors is getting higher and higher, while the size is getting smaller and smaller. The increase in motor power density has put forward higher requirements for motor heat dissipation.

[0005] During motor operation, heat loss from the stator core is a significant source of heat. This can be achieved by oil cooling the stator through heat dissipation channels provided on the stator. However, conventional heat dissipation methods for motor stators are currently inadequate, and the cooling effect needs to be improved. Summary of the Invention

[0006] The present application provides a stator core, a motor, a powertrain and an electric vehicle for cooling the ends of windings. The stator core can realize oil injection at the ends of the stator and has a high oil injection speed.

[0007] In a first aspect, the present application provides a stator core for cooling winding ends, which can be used in motors in the field of electric vehicles. The stator core includes a plurality of stator punchings, which are arranged in sequence and adjacent to each other along the axial direction of the stator core to form at least a portion of the stator core. Each stator punching includes a center hole and a plurality of cooling holes, which are spaced apart along the circumference of the stator punching, and each cooling hole is spaced apart between the center hole and the outer circumferential surface of the stator punching. After the plurality of stator punchings are arranged adjacent to each other along the axial direction of the stator core, the center holes of the plurality of stator punchings are connected to form a receiving hole for accommodating a rotor. The plurality of stator punchings include a first punching and a second punching. Specifically, the first punching is arranged adjacent to the second punching along the axial direction of the stator core. Each cooling hole of the first punching is used to connect to a cooling hole of the second punching and to cool the stator winding ends, thereby forming a channel for the flow of a cooling medium. Along at least one of the radial direction and the circumferential direction of the stator core, each cooling hole of the first punching plate is eccentrically arranged relative to a cooling hole of the second punching plate connected thereto.

[0008] The stator core's staggered cooling holes in the first and second punching sheets reduce the cross-sectional area of ​​the channel through which the cooling medium flows. Under the condition of a constant cooling medium flow rate driven by the oil pump, the cooling medium's flow rate increases as the channel cross-sectional area decreases. When the first punching sheet serves as the stator punching sheet at the end of the stator core, the staggered arrangement of the first and second cooling holes allows the cooling medium to be ejected at a higher velocity, thereby achieving excellent liquid cooling and heat dissipation.

[0009] In one possible implementation, along the radial direction of the stator core, the distance between the cooling hole of the first punch and the center hole is smaller than the distance between the cooling hole of the second punch and the center hole, so that a cooling hole of the first punch is offset relative to a cooling hole of the second punch connected thereto along the radial direction of the stator core.

[0010] In one possible implementation, a cooling hole in a first punch is connected to a cooling hole in a second punch, and another cooling hole in a first punch is connected to another cooling hole in a second punch. Along the circumference of the stator core, the distance between one cooling hole and another cooling hole in a first punch is not equal to the distance between one cooling hole in a second punch and another cooling hole in a first punch, and the distance between one cooling hole and another cooling hole in a second punch is not equal to the distance between one cooling hole in a first punch and another cooling hole in a second punch, thereby achieving an offset arrangement of one cooling hole in a first punch relative to one cooling hole in a connected second punch along the circumference of the stator core.

[0011] In one possible implementation, the diameter of the cooling hole of the first punch is smaller than or equal to the diameter of the cooling hole of the second punch. The reduction in the diameter of the cooling hole of the first punch can further increase the flow rate of the coolant when flowing from the cooling hole of the second punch to the cooling hole of the first punch.

[0012] In one possible implementation, the number of cooling holes in the first punch can be set to be smaller than the number of cooling holes in the second punch. When the cooling holes in the first punch are used as axial liquid outlets of the stator core, the number of liquid outlets that are connected can be reduced, thereby increasing the flow rate.

[0013] In one possible implementation, the plurality of stator punches include a plurality of second punches and another second punch, and the plurality of second punches are arranged between the one second punch and the another second punch along the axial direction of the stator core. Along the axial direction of the stator core, the plurality of cooling holes of one second punch are respectively used to connect the plurality of cooling holes of adjacent second punches, the plurality of cooling holes of another second punch are respectively used to connect the plurality of cooling holes of adjacent second punches, and the plurality of cooling holes of each second punch in the plurality of second punches are respectively used to connect the plurality of cooling holes of adjacent second punches. Between any two adjacent second punches, one cooling hole of one second punch is used to connect the second cooling holes of another second punch to form a channel for the flow of the cooling medium. By designing the structure and arrangement of the plurality of second punches, the flow direction of the cooling medium can be changed.

[0014] In one possible implementation, the spacing between two circumferentially adjacent cooling holes in a second punching plate and the center hole is greater than the spacing between the other cooling hole and the center hole. When the stator core includes multiple second punching plates, and the multiple second punching plates are stacked and rotated a certain angle along the circumference of the stator core, an oblique flow channel can be formed, directing the cooling medium toward the center of the stator core, facilitating spraying of the cooling medium into the end windings.

[0015] Specifically, between any two connected cooling holes of the second punching sheets, along the radial direction of the stator core, the distance between one cooling hole and the center hole is greater than the distance between the other cooling hole and the center hole.

[0016] In one possible implementation, the plurality of stator punchings include a third punching, and the third punching is arranged adjacent to another second punching along the axial direction of the stator core. In the radial direction of the stator core, the cooling holes of the third punching are connected to the outer peripheral surface of the third punching. In the axial direction of the stator core, the multiple cooling holes of the third punching are respectively used to connect to the multiple cooling holes of another second punching, and the distance between the cooling holes of the third punching and the center hole is less than or equal to the distance between the cooling holes of the second punching and the center hole. The cooling holes of the third punching can guide the cooling medium entering between the housing and the stator core to the second punching.

[0017] In one possible implementation, the plurality of stator punchings include a third punching and a fourth punching, the fourth punching being arranged adjacent to another second punching along the axial direction of the stator core, and the third punching being arranged adjacent to the side of the fourth punching facing away from the other second punching along the axial direction of the stator core. Along the radial direction of the stator core, the cooling hole of the third punching is connected to the outer peripheral surface of the third punching. Along the axial direction of the stator core, the plurality of cooling holes of the fourth punching are respectively used to connect at least one cooling hole of another second punching with at least one cooling hole of the third punching. The cooling hole of the fourth punching can form a collection space between the second punching and the third punching that can accommodate more cooling media, and the liquid outlet provides a more sufficient oil supply, ensuring the oil pressure and oil speed sprayed out of the liquid outlet, and can also reduce the assembly precision requirements.

[0018] In one possible implementation, along the circumference of the stator core, the circumferential size of the cooling hole of the fourth punch is greater than the spacing between two adjacent cooling holes of the second punch and the spacing between two adjacent cooling holes of the third punch, so that the cooling hole of the fourth punch can simultaneously connect to multiple cooling holes of the second punch and multiple cooling holes of the third punch.

[0019] In one possible implementation, each cooling hole in the fourth punch is connected to the outer circumferential surface of the fourth punch along the radial direction of the stator core. At least two adjacent cooling holes among the plurality of cooling holes in the fourth punch are connected along the circumference of the stator core. An annular channel for the flow of cooling medium can be formed between the third punch and the second punch.

[0020] In a second aspect, the present application provides a motor comprising a housing and any one of the stator cores provided in the first aspect. The housing is sleeved over the outer circumference of the stator core and includes a liquid inlet for communicating with at least one cooling hole of a second punching plate. After entering the housing, the cooling medium can ultimately flow to the cooling hole of the second punching plate.

[0021] In a third aspect, the present application provides a powertrain comprising a reducer or transmission and a motor according to the first aspect and any implementation thereof, wherein a motor shaft of the motor is drivingly connected to an input shaft of the reducer or the transmission. Because the motor has excellent heat dissipation performance, the heat dissipation and power performance of the powertrain can be improved.

[0022] In a fourth aspect, the present application provides an electric vehicle. The electric vehicle includes wheels, a transmission mechanism, and the powertrain according to the second aspect and any implementation thereof. The powertrain drives the wheels via the transmission mechanism. The electric vehicle provided in this application has excellent heat dissipation and power performance.

[0023] For the technical effects that can be achieved in the above-mentioned second to fourth aspects, please refer to the description of the technical effects that can be achieved by the corresponding design scheme in the above-mentioned first aspect, and this application will not repeat them here. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] FIG1 is a schematic structural diagram of an electric vehicle provided in an embodiment of the present application;

[0025] FIG2 is a schematic structural diagram of a powertrain provided in an embodiment of the present application;

[0026] FIG3 a is a schematic structural diagram of a housing and a stator core of a motor provided in an embodiment of the present application;

[0027] FIG3 b is a schematic structural diagram of a housing and a stator core of a motor provided in an embodiment of the present application;

[0028] FIG4 a is a schematic structural diagram of a first punching sheet and a second punching sheet of a stator core provided in an embodiment of the present application;

[0029] FIG4 b is a schematic structural diagram of a first punching sheet and a second punching sheet of a stator core provided in an embodiment of the present application;

[0030] FIG5 a is a schematic diagram of a partial structure of a first punching sheet and a second punching sheet of a stator core provided in an embodiment of the present application;

[0031] FIG5 b is a schematic cross-sectional view of a partial structure of a first punching sheet and a second punching sheet of a stator core provided in an embodiment of the present application;

[0032] FIG6 a is a schematic diagram of a partial structure of a first punching sheet and a second punching sheet of a stator core provided in an embodiment of the present application;

[0033] FIG6 b is a schematic cross-sectional view of a partial structure of a first punching sheet and a second punching sheet of a stator core provided in an embodiment of the present application;

[0034] FIG7 is a schematic diagram of a partial structure of a first punching sheet and a second punching sheet of a stator core provided in an embodiment of the present application;

[0035] FIG8 is a schematic cross-sectional view of a partial structure of a first punching sheet and a plurality of second punching sheets of a stator core provided in an embodiment of the present application;

[0036] FIG9 is a schematic structural diagram of a second punching sheet of a stator core provided in an embodiment of the present application;

[0037] FIG10 a is a schematic cross-sectional view of a partial structure of a plurality of second punching sheets of a stator core provided in an embodiment of the present application;

[0038] FIG10 b is a schematic cross-sectional view of a partial structure of a plurality of second punching sheets of a stator core provided in an embodiment of the present application;

[0039] FIG11 is a schematic diagram of a partial structure of stacked multiple second punching sheets of a stator core provided by an embodiment of the present application;

[0040] FIG12 is a schematic cross-sectional view of a partial structure of stacked second punching sheets of a stator core provided in an embodiment of the present application;

[0041] FIG13a is a schematic structural diagram of a stator core provided in an embodiment of the present application;

[0042] FIG13 b is an exploded view of a stator core provided in an embodiment of the present application;

[0043] FIG14a is a schematic structural diagram of a second punching sheet and a fourth punching sheet of a stator core provided in an embodiment of the present application;

[0044] FIG14 b is a schematic structural diagram of a third punching sheet and a fourth punching sheet of a stator core provided in an embodiment of the present application;

[0045] FIG15 is a schematic diagram of a partial structure of a stator core provided in an embodiment of the present application;

[0046] FIG16 is a schematic diagram of a cooling medium flow path of a stator core provided in an embodiment of the present application;

[0047] FIG17 is an exploded view of a stator core provided in an embodiment of the present application;

[0048] FIG18a is a schematic structural diagram of a second punching sheet and a fourth punching sheet of a stator core provided in an embodiment of the present application;

[0049] FIG18 b is a schematic structural diagram of a third punching sheet and a fourth punching sheet of a stator core provided in an embodiment of the present application.

[0050] Figure markings: 1000-powertrain; 2000-transmission mechanism; 3000-wheel; 100-motor; 200-reducer; 10-stator core; 101-liquid inlet; 102-liquid outlet; 103-stator teeth; 104-winding slots; 105-accommodating holes; 106-axial grooves; 20-stator winding; 30-rotor; 40-motor shaft; 50-housing; 51-liquid inlet pipe; 52-radial grooves; 1-stator punching sheet; 1a-first punching sheet; 1b-second punching sheet; 1c-third punching sheet; 1d-fourth punching sheet; 11-center hole; 12, 12a, 12a1, 12a2, 12b, 12b1, 12b2, 12c, 12d-cooling holes; 13-punching sheet groove. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical solutions and advantages of this application clearer, this application will be further described in detail below with reference to the accompanying drawings.

[0052] The terminology used in the following embodiments is for the purpose of describing specific embodiments only and is not intended to limit the present application. As used in the specification and appended claims of this application, references to "one embodiment" or "some embodiments" in this specification mean that a particular feature, structure, or characteristic described in conjunction with that embodiment is included in one or more embodiments of the present application.

[0053] When a motor runs at high speed, heat loss from the stator core is the primary source of heat. Traditionally, oil cooling has been used to dissipate heat from the motor's stator. Specifically, oil is passed through the back of the stator core and sprayed onto the end coils of the stator windings to dissipate the heat. However, this cooling method is ineffective and cannot meet the high heat dissipation requirements associated with increased motor power density. Furthermore, this cooling method imposes restrictions on motor design, reduces space utilization, and the addition of auxiliary oil spraying structures increases production costs.

[0054] Based on this, the embodiments of the present application provide a stator core, a motor, a powertrain and an electric vehicle for cooling the ends of the windings. The stator core can realize oil injection at the ends of the stator and has a relatively high oil injection speed.

[0055] Figure 1 is a schematic diagram of an electric vehicle provided in accordance with an embodiment of the present application. Referring to Figure 1 , the electric vehicle provided in accordance with an embodiment of the present application includes a powertrain 1000, a transmission mechanism 2000, and wheels 3000. Powertrain 1000 drives wheels 3000 via transmission mechanism 2000. Powertrain 1000 is used to convert electrical energy into mechanical energy. Transmission mechanism 2000 is used to provide a transmission connection between powertrain 1000 and wheels 3000.

[0056] FIG2 is a schematic diagram of a powertrain provided in an embodiment of the present application. As shown in FIG2 , the powertrain 1000 provided in an embodiment of the present application includes a motor 100 and a reducer 200. The motor 100 and the reducer 200 are transmission-connected. The motor 100 is used to drive a transmission mechanism 2000 of an electric vehicle through the reducer 200. The motor 100 includes a stator core 10, a stator winding 20, a rotor 30, a motor shaft 40, and a housing 50. The rotor 30 is coaxially fixed to the motor shaft 40, and the motor shaft 40 is transmission-connected to the reducer 200. The stator core 10 is sleeved on the outside of the rotor 30, the stator winding 20 is wound on the stator core 10, and the housing 50 is arranged outside the stator core 10. The reducer 200 may also be a transmission. It should be understood that the axial direction of the stator core 10 is also the axial direction of the motor 100 , the radial direction of the stator core 10 is also the radial direction of the motor 100 , and the circumferential direction of the stator core 10 is also the circumferential direction of the motor 100 .

[0057] The motor 100 provided in the embodiment of the present application is a motor with liquid-cooled stator windings, specifically, the cooling medium used to dissipate heat for the stator 10 can simultaneously spray the cooling medium to the end windings of the stator windings 20 to dissipate heat.

[0058] Figure 3a illustrates the structure of the stator core 10 and housing 50 of the motor 100. As shown in Figure 3a, the housing 50 includes a hollow liquid inlet pipe 51. One end of the liquid inlet pipe 51 is fixed to the outer circumference of the housing 50, and the end of the liquid inlet pipe 51 facing away from the outer circumference of the housing 50 forms a liquid inlet port 101. The axial end surface of the stator core 10 includes multiple liquid outlets 102, each of which is used to discharge cooling fluid to dissipate heat from the ends of the stator winding 20.

[0059] For example, along the circumference of the motor 100, a plurality of liquid outlets 102 are arranged at intervals. The number and arrangement rules of the liquid outlets 102 can be adjusted according to actual cooling requirements and process conditions. The stator core 10 has a channel for the circulation of the cooling medium, and the liquid inlet 101 and the plurality of liquid outlets 102 are respectively connected to the channel. The cooling medium can be injected into the channel in the stator core 10 through the liquid inlet 101, and the cooling medium is ejected to the plurality of liquid outlets 102 through the circulation channel in the stator core 10. When the cooling medium circulates in the stator core 10, it can dissipate heat to the stator winding 20 through the stator core 10. After the cooling medium is ejected from the liquid outlet 102, it can be sprayed on the end of the stator winding 20 located at the end of the stator core 10.

[0060] Continuing with Figure 3a , the stator core 10 includes stator teeth 103, winding slots 104, and a receiving hole 105. The receiving hole 105 is located at the axial center of the stator core 10 and extends axially through the stator core 10. There are multiple winding slots 104, spaced apart along the circumference of the stator core 10. Each winding slot 104 is radially connected to a receiving hole 105. Along the circumference of the stator core 10, a stator tooth 103 is formed between any two adjacent winding slots 104. The winding slots 104 are used to accommodate portions of the stator winding 20, and the receiving hole 105 is used to accommodate the rotor 30.

[0061] As shown in Figure 3b, the stator core 10 is separated from the housing 50. The stator core 10 includes a plurality of stator punchings 1, which are arranged along the axial direction of the stator core 10. Each stator punching 1 includes a center hole 11 and a plurality of cooling holes 12. The center hole 11 is located at the center of the stator punching 1, and the plurality of cooling holes 12 are arranged at intervals along the circumference of the stator core 10. Each cooling hole 12 is arranged between the center hole 11 and the outer peripheral surface of the stator punching 1 along the radial direction of the stator core 10. Along the axial direction of the stator core 10, the center hole 11 and each cooling hole 12 pass through the stator punching 1. Illustratively, each stator lamination 1 further includes a plurality of lamination grooves 13, which are spaced apart along the circumference of the stator core 10 and extend axially through the stator lamination 1. Each lamination groove 13 is radially connected to the center hole 11 of the stator core 10, and the bottom of the lamination groove 13 faces away from the center of the stator lamination 1. The liquid outlet 102 of the stator core 10 is specifically formed on the stator lamination 1 located at the axial end of the stator core 10. The stator lamination 1 can be considered as the oil injection structure of the stator core 10. When multiple stator punching sheets 1 are stacked axially along the stator core 10, the center holes 11 of the multiple stator punching sheets 1 can be interconnected to form a receiving hole 105 of the stator core 10, and the punching grooves 13 of the multiple stator punching sheets 1 are respectively connected to form a winding slot 104. The structure between any two punching grooves 13 adjacent to each other along the circumference of the stator core 10 can be stacked to form a stator tooth 103 of the stator core 10. The outer peripheral surface of the stator core 10 includes a plurality of axial grooves 106, which extend along the axial direction of the stator core 10. The plurality of axial grooves 106 are arranged at intervals along the circumference of the stator core 10.

[0062] The shell 50 is used to circumferentially seal around the stator core 10. The shell 50 is cylindrical, and the inner wall of the shell 50 includes a radial groove 52. The radial groove 52 is formed by a groove provided on the inner wall of the shell 50. The radial groove 52 extends along the circumference of the shell 50, and the bottom of the radial groove 52 is connected to the liquid inlet 101 through the liquid inlet pipe 51. When the shell 50 sealing sleeve is provided on the outer peripheral surface of the stator core 10 composed of multiple punchings 1, the radial groove 52 is connected to at least one cooling hole 12 of the stator punching 1 through the axial groove 106 on the outer peripheral surface of the stator core 10. The corresponding relationship between the number of axial grooves 106 and cooling holes 12 is not limited, as long as at least one cooling hole 12 is connected to the radial groove 52 through at least one axial groove 106.

[0063] Figure 4a shows a partial structure of the stator core 10. As shown in Figure 4a, the multiple stator punchings 1 of the stator core 10 include a first punching 1a and a second punching 1b. Along the axial direction of the stator core 10, a first punching 1a is arranged adjacent to a second punching 1b. The center hole 11 of the first punching 1a is connected to the center hole 11 of the second punching 1b. Each cooling hole 12 of the first punching 1a is used to connect to a cooling hole 12 of the second punching 1b and is used to cool the end of the stator winding 20.

[0064] As shown in FIG4a , the cooling holes 12 can allow a cooling medium to flow through. When the cooling medium flows through the cooling holes 12, the cooling medium can dissipate heat from the stator sheet 1. The cooling holes 12 connecting the first sheet 1a and the second sheet 1b can be connected to allow the cooling medium to flow. For ease of illustration, the cooling holes 12 of the first sheet 1a and the cooling holes 12 of the second sheet 1b are both circular holes with the same aperture size.

[0065] As shown in Figure 4b, taking any two connected cooling holes 12 of the first punch 1a and the second punch 1b as an example, the cooling hole 12 of the first punch 1a is set as cooling hole 12a, and the cooling hole 12 of the second punch 1b is set as cooling hole 12b, and the cooling hole 12a and the cooling hole 12b are connected along the axial direction of the stator core 10. The cooling hole 12a and the cooling hole 12b are eccentrically arranged along the radial direction of the stator core 10, so that the distance from the cooling hole 12a to the center hole 11 is not equal to the distance from the cooling hole 12b to the center hole 11. The center holes 11 of the first punch 1a and the second punch 1b are equal in shape and size. It can also be considered that the spacing h1 between the cooling hole 12a and the center Oa of the first punch 1a is not equal to the spacing h2 between the cooling hole 12b and the center Ob of the second punch 1b.

[0066] Figure 5a shows a schematic diagram of the structure in which the cooling hole 12a of the first punch 1a is connected to the cooling hole 12b of the second punch 1b. For example, when observed along the axial direction of the stator core 10, the first punch 1a and the second punch 1b are stacked along the axial direction of the stator core 10, the center holes 11 of the first punch 1a and the second punch 1b are connected and overlapped, the center Oa of the first punch 1a and the center Ob of the second punch 1b overlap as center O, and the multiple punch grooves 13 of the first punch 1a and the multiple punch grooves 13 of the second punch 1b are respectively connected and overlapped. In a group of connected cooling holes 12a and cooling holes 12b, the spacing h1 between the cooling hole 12a and the center O is smaller than the spacing h2 between the cooling hole 12b and the center O, and the cooling hole 12a is eccentrically arranged with the cooling hole 12b along the radial direction of the stator core 10. Along the radial direction of the stator core 10, the cooling holes 12a are offset relative to the cooling holes 12b by a distance p toward the center O of the stator core 10. This distance p is the difference between the spacing h1 and the spacing h2. It should be understood that the cooling holes 12a and 12b need to be connected and offset radially along the stator core 10. For example, for a circular cooling hole 12a and a centrally located cooling hole 12b, the offset distance between the cooling holes 12a and 12b should be no greater than the radial dimension of either cooling hole 12a, such that the axial projections of the cooling holes 12a and 12b along the stator core 10 partially overlap.

[0067] The cooling holes 12a of the first punch 1a and the cooling holes 12b of the second punch 1b are connected for the flow of the cooling medium. The cooling hole 12a is offset relative to the cooling hole 12b, which changes the structure of the flow channel between the cooling holes 12a and 12b. Specifically, as shown in FIG5b, when the cooling medium flows from the cooling hole 12b to the cooling hole 12a, the cross-sectional area occupied by the cooling medium flowing within the cooling hole 12b can be referred to as region A2. After the cooling hole 12a is offset relative to the cooling hole 12b in the radial direction of the stator core 10, when the cooling medium enters the cooling hole 12a from the cooling hole 12b, the cross-sectional area of ​​the channel for the cooling medium flow suddenly changes to the area shown in region A1. Region A2 is larger than region A1. The shaded area A' is the portion where region A2 is larger than region A1. The cooling medium in the cooling hole 12b cannot pass through the shaded area A', resulting in the cross-sectional area of ​​the channel for the cooling medium flow suddenly changing from region A2 to region A1, and the flow cross-sectional area becomes smaller. When the oil pump power is the same, the flow direction of the cooling medium is the same, and the rate at which the cooling medium enters the cooling hole 12a will increase. In other words, the flow rate of the cooling medium can be changed by designing the offset of the cooling hole 12a and the cooling hole 12b.

[0068] In some embodiments, the cooling hole 12a of the first punch 1a is connected to the cooling hole 12b of the second punch 1b, and the cooling holes 12a and the cooling holes 12b are staggered along the circumference of the stator core 10. For example, as shown in Figure 6a, a first punch 1a includes two adjacent cooling holes 12a, one cooling hole 12a1 and the other cooling hole 12a2. A second punch 1b includes two adjacent cooling holes 12b, one cooling hole 12b1 and the other cooling hole 12b2. The first punch 1a and the second punch 1b are arranged adjacent to each other along the axial direction of the stator core 10. Taking the radial position shown by the dotted line in Figure 5a as an example, the cooling hole 12a1 is connected to the cooling hole 12b1 and is offset by a distance q, and the cooling hole 12a2 is connected to the cooling hole 12b2 and is offset by a distance q. Along the circumferential direction of the stator core 10 , the distance between the cooling hole 12 a 1 and the cooling hole 12 a 2 is not equal to the distance between the cooling hole 12 b 1 and the cooling hole 12 a 2 .

[0069] Figure 6b shows the cross-sectional structure of two circumferentially adjacent cooling holes 12a in the first punch 1a and two circumferentially adjacent cooling holes 12a in the second punch 1b. For example, along the circumference of the stator core 10, cooling hole 12a1 is offset to the left by a distance q relative to cooling hole 12b1, and cooling hole 12a2 is offset to the left by a distance q relative to cooling hole 12b2. The distance between cooling hole 12a1 and cooling hole 12a2 is m1, and the distance between cooling hole 12b1 and cooling hole 12a2 is m2, where m1>m2.

[0070] Taking cooling holes 12a1 and 12b1 in Figure 6b as an example, when the coolant flows from cooling hole 12b1 to cooling hole 12a1, the cross-sectional area occupied by the coolant flowing through cooling hole 12b1 can be seen in region A2. After cooling hole 12a1 is offset relative to cooling hole 12b1 along the circumference of stator core 10, when the coolant enters cooling hole 12a1 from cooling hole 12a1, the cross-sectional area of ​​the channel for the coolant flow suddenly changes to the area shown in region A1. Region A2 is larger than region A1. The shaded area A', which is the portion where region A2 is larger than region A1, prevents the coolant in cooling hole 12b1 from passing through shaded area A'. As a result, the cross-sectional area of ​​the channel for the coolant flow suddenly changes from region A2 to region A1, reducing the flow cross-section. At the same flow rate, the rate at which the coolant enters cooling hole 12a1 increases. In other words, by designing the offset between cooling holes 12a1 and 12b1, the flow rate of the coolant can be changed.

[0071] In some possible embodiments, the cooling hole 12a of the first punch 1a can be offset relative to the cooling hole 12b of the second punch 1b along the circumferential and radial directions of the stator core 10, so that when the cooling medium flows between the cooling hole 12a and the cooling hole 12b, the flow rate changes due to the change in the flow cross-section.

[0072] As shown in the above embodiment, if the first punching sheet 1a is set as the stator punching sheet 1 at the axial end of the stator core 10, the cooling hole 12a of the first punching sheet 1a is equivalent to the liquid outlet 102 at the end of the stator core 10. The cooling medium flows from the cooling hole 12b of the second punching sheet 1b to the cooling hole 12a of the first punching sheet 1a and is sprayed out. The offset setting of the cooling hole 12a relative to the cooling hole 12b can increase the spraying speed of the cooling medium. For the stator core 10, in the design of the stator punching sheet 1, the stator punching sheet 1 at the axial end does not need to be designed with a small-aperture oil injection hole to increase the oil injection rate. The offset of the cooling hole 12a of the first punching sheet 1a and the cooling hole 12b of the second punching sheet 1b can reduce the aperture of the oil injection channel and increase the oil injection flow rate.

[0073] It should be understood that when the first punching sheet 1a is set as the stator punching sheet 1 at the axial end of the stator core 10, the cooling hole 12a of the first punching sheet 1a is equivalent to the liquid outlet 102 at the end of the stator core 10. The cooling hole 12a of the first punching sheet 1a is offset toward the center of the stator core 10 relative to the cooling hole 12b of the connected second punching sheet 1b, so that the cooling medium can be directed to the stator winding 20 located at the end of the stator core 10, thereby achieving liquid spray cooling of the end winding.

[0074] Taking the example of the cooling holes 12a of the first punch 1a and the cooling holes 12b of the second punch 1b being connected and offset in the radial direction of the stator core 10, in some embodiments, as shown in FIG7 , the diameter of the cooling hole 12a of the first punch 1a is smaller than or equal to the diameter of the cooling hole 12b of one of the second punches 1b. This further increases the rate at which the coolant is ejected from the cooling hole 12a.

[0075] It should be understood that when the first punching sheet 1a is set as the stator punching sheet 1 at the axial end of the stator core 10, the number of first punching sheets 1a can be one, and the effect of increasing the injection rate can be achieved by cooperating with an adjacent second punching sheet 1b. Of course, there can also be two or three first punching sheets 1a, but the number does not need to be too large. The number of second punching sheets 1b can be multiple, and multiple second punching sheets 1b are arranged adjacent to each other along the axial direction of the stator core 10. The multiple cooling holes 12b of the multiple second punching sheets 1b are respectively connected to form a channel for the circulation of the cooling medium.

[0076] Exemplarily, as shown in FIG8 , a plurality of stator punching sheets 1 include a plurality of second punching sheets 1b and another second punching sheet 1b, and the plurality of second punching sheets 1b are arranged between the above-mentioned second punching sheet 1b and the another second punching sheet 1b along the axial direction of the stator core 10. Exemplarily, as shown in FIG8 , a first punching sheet 1a and a plurality of second punching sheets 1b are arranged adjacent to each other in sequence along the axial direction of the stator core 10. Among the plurality of second punching sheets 1b, the second punching sheet 1b-1 is arranged adjacent to the first punching sheet 1a, and the second punching sheet 1b-2 is the second punching sheet 1b farthest from the first punching sheet 1a. Exemplarily, two second punching sheets 1b-3 are arranged between the second punching sheet 1b-1 and the second punching sheet 1b-2. The cooling holes 12b of the plurality of second punching sheets 1b are connected in sequence, and the cooling holes 12b of the second punching sheet 1b-1 are connected to the cooling holes 12a of the first punching sheet 1a and are offset and misaligned.

[0077] As shown in Figure 9, a second punching plate 1b has a variation in the distance between a plurality of cooling holes 12b and the center O of the second punching plate 1b along the circumference of the stator core 10. For example, for two cooling holes 12b adjacent to each other along the circumference of the stator core 10, the distance h22 between the latter cooling hole 12b and the center O of the second punching plate 1b in the clockwise direction is greater than the distance h21 between the former cooling hole 12b and the center O of the second punching plate 1b. For example, the distances between the plurality of cooling holes 12b of the second punching plate 1b and the center O gradually increase. For example, the plurality of cooling holes 12b are distributed along an asymptote, and the base circle of the asymptote has the distance between the cooling hole 12b closest to the center O of the second punching plate 1b and the center O as a radius.

[0078] For each second punch 1b, in a clockwise direction, the cooling hole 12b closest to the center O of the second punch 1b is the first cooling hole 12b, and the distances between the multiple cooling holes 12b following the first cooling hole 12b and the center O of the second punch 1b gradually increase. The distance between the k+1th cooling hole 12b and the center O of the second punch 1b is greater than the distance between the kth cooling hole 12b and the center O of the second punch 1b.

[0079] When multiple second punching sheets 1b shown in FIG9 are arranged adjacent to each other along the axial direction of the stator core 10, between two adjacent second punching sheets 1b, the multiple cooling holes 12b of the previous second punching sheet 1b are respectively connected to the multiple cooling holes 12b of the next second punching sheet 1b.

[0080] In one arrangement, as shown in FIG10 a , the distance between each of the two connected cooling holes 12 b and the center of the second punching plate 1 b is equal. In this structure, each of the second punching plates 1 b and the cooling holes 12 b with equal distances from the center are sequentially connected to form a cooling channel D for the flow of the cooling medium. The cooling channel D is parallel to the axial direction of the stator core 10.

[0081] In one arrangement, as shown in Figure 10b, the distances between the two connected cooling holes 12b and the centers of the second punches 1b are not equal. Along the radial direction of the stator core 10, between the two cooling holes 12b connected between two adjacent second punches 1b, the distance between the cooling hole 12b of one second punch 1b and the center of the second punch 1b is greater than the distance between the cooling hole 12b of the other second punch 1b and the center of the second punch 1b. The center of the cooling channel formed by the two cooling holes 12b is offset along the radial direction of the second punch 1b, causing the cooling channel to tilt and changing the flow direction of the coolant. In this structure, the cooling channel D formed by the connected cooling holes 12b is set at an angle to the axial direction of the stator core 10. When a group of cooling holes 12b of multiple second punches 1b are connected in sequence to form a cooling channel D that passes through all the second punches 1b, the cooling hole 12b of the second punch 1b-1 adjacent to the first punch 1a is closest to the center of the second punch 1b, and the cooling hole 12b of the second punch 1b-2 farthest from the first punch 1a is farthest from the center of the second punch 1b. The inclined cooling channel D is inclined toward the axial direction of the stator core 10, so that the cooling medium can be inclined to the end winding.

[0082] The arrangement of the cooling holes 12b of the multiple second punches 1b shown in Figure 10b can be achieved using the multiple second punches 1b shown in Figure 11. As shown in Figure 11, the local structure of the multiple second punches 1b defines the cooling hole 12b closest to the center O of each second punch 1b as cooling hole 12b-1, and the cooling hole 12b farthest from the center of the second punch 1b as cooling hole 12b-2. Along the circumference of the second punches 1b, any two adjacent second punches 1b are relatively deflected by a set angle, which is the central angle between the two cooling holes 12b.

[0083] After the plurality of second punching plates 1b are deflected and stacked in sequence, the cooling channel D formed by the interconnected cooling holes 12b can be tilted along the radial direction of the stator core 10, thereby changing the flow direction of the coolant. Specifically, with the cooling hole 12b closest to the center of the second punching plate 1b as a reference, the plurality of second punching plates 1b are arranged adjacent to each other so that the kth cooling hole 12b of one second punching plate 1b is connected to the k+1th cooling hole 12b of another second punching plate 1b, where k is an integer greater than or equal to 1. The direction of the channel formed by the interconnected cooling holes 12b is tilted, thereby changing the flow direction of the coolant.

[0084] As shown in Figure 11, at N1, N1 is the position of the cooling hole 12b-2 of the first second punch 1b that is farthest from the center of the second punch 1b. One cooling hole 12b-2 of the first second punch 1b can be connected to the last cooling hole 12b of the last second punch 1b, so that the cooling holes 12b of multiple second punches 1b at this position are connected in sequence to form a cooling channel. Here, since the kth cooling hole 12b of the i+1th second punch 1b is connected to the k+1th cooling hole 12b of the i-th second punch 1b, the direction of the cooling channel here is inclined along the radial direction of the stator core 10, and the cooling medium can be deflected outward or inward along the radial direction of the stator core 10 when circulating.

[0085] As shown in Figure 11, N2 is the position of the cooling hole 12b-1 of the first second punch 1b that is closest to the center of the second punch 1b. If the cooling hole 12b-1 of the first second punch 1b is blocked by the second second punch 1b, a cooling channel that passes through all the second punches 1b cannot be formed. When multiple second punches 1b are arranged axially, there is always a cooling hole 12b blocked between any two adjacent second punches 1b, resulting in the cooling channel being blocked and unable to communicate. It should be understood that when the cooling channel is blocked by a second punch 1b, for cooling holes 12b at different angular positions, the second punch 1b that blocks the cooling channel may be one of the second punches 1b, not limited to the second punches 1b on both sides. Figure 12 illustrates a situation where the cooling holes 12b of the two second punches 1b between the first second punch 1b-1 and the last second punch 1b-2 are not connected, resulting in the blockage of the outer cooling channel.

[0086] It should be understood that when the distance between any two circumferentially adjacent cooling holes 12b of the second punching plate 1b changes, the direction of the cooling channel will be tilted along the circumference of the stator core 10, causing the cooling medium to be eccentrically deflected along the circumference of the stator core 10. When the communication mode of the cooling holes 12b is tilted simultaneously in the circumferential or radial direction of the stator core 10, the stator core 10 can finally spray the coolant in a rotating manner. Of course, the spray direction of the coolant can be irregular, and this is not limited by the embodiment of the present application. Two axially adjacent second punching plates 1b can be rotated circumferentially relative to the center of the stator core 10 by a set angle, and the set angle is the angle between two adjacent cooling holes 12b of the same second punching plate 1b.

[0087] As shown in Figure 13a, a stator core 10 includes multiple stator sheets 1 including a first sheet 1a, a second sheet 1b, a third sheet 1c and a fourth sheet 1d. Specifically, the stator core 10 is arranged with a fourth sheet 1d, a second sheet 1b and a third sheet 1c at both axial ends of the third sheet 1c. Among them, the second sheet 1b is a combination of multiple second sheets 1b, specifically the multiple second sheets 1b shown in Figure 8 in the above embodiment. The fourth sheet 1d is arranged between the multiple second sheets 1b and the third sheet 1c. It can be considered that the first sheet 1a is arranged adjacent to a second sheet 1b-1 in Figure 8 along the circumferential direction of the stator core 10, the fourth sheet 1d is arranged adjacent to another second sheet 1b-2 in Figure 8 along the axial direction of the stator core 10, and the third sheet 1c is arranged adjacent to the fourth sheet 1d on the side away from the other second sheet 1b-2 along the axial direction of the stator core 10. When there is only one fourth punching sheet 1d, the fourth punching sheet 1d is arranged between the second punching sheet 1b and the third punching sheet 1c. The center holes 11 of the first punching sheet 1a, the second punching sheet 1b, the third punching sheet 1c, and the fourth punching sheet 1d coincide with each other in the axial projection along the stator core 10, and the distances from the outer circumferences of the first punching sheet 1a, the second punching sheet 1b, the third punching sheet 1c, and the fourth punching sheet 1d to the center hole 11 are equal.

[0088] Figure 13b shows an exploded view of the stator core 10. Along the radial direction of the stator core 10, the cooling hole 12c of the third punch 1c is connected to the outer peripheral surface of the third punch 1c. It can be considered that the cooling hole 12c of the third punch 1c is at least a part of the axial groove 106 of the stator core 10. Along the axial direction of the stator core 10, the multiple cooling holes 12d of the fourth punch 1d are respectively used to connect at least one cooling hole 12b of another second punch 1b-2 with at least one cooling hole 12c of the third punch 1c. Exemplarily, the cooling holes 12d of the fourth punch 1d are connected to the outer peripheral surface of the fourth punch 1d along the radial direction of the stator core 10, and each cooling hole 12d of the fourth punch 1d is used to connect one cooling hole 12b of the second punch 1b with at least one cooling hole 12c of the third punch 1c. The number of cooling holes 12d of the fourth punch 1d may be smaller than the number of cooling holes 12 of the second punch 1b and the number of cooling holes 12 of the third punch 1c.

[0089] Figure 14a shows a structure in which the second punching plate 1b and the fourth punching plate 1d are arranged and stacked. Along the axial direction of the stator core 10, the orthographic projection of the cooling hole 12d of the fourth punching plate 1d on the second punching plate 1b covers the cooling hole 12b of the second punching plate 1b. Along the circumferential direction of the stator core 10, the circumferential size of the cooling hole 12d of the fourth punching plate 1d is larger than the circumferential size of the cooling hole 12b of the second punching plate 1b. Along the radial direction of the stator core 10, the radial size of the cooling hole 12d of the fourth punching plate 1d is larger than the radial size of the cooling hole 12b of the second punching plate 1b.

[0090] Figure 14b shows a structure in which the third punching plate 1c and the fourth punching plate 1d are arranged and stacked. Along the axial direction of the stator core 10, the cooling hole 12d of the fourth punching plate 1d covers at least one cooling hole 12c of the third punching plate 1c in the orthographic projection of the third punching plate 1c. Along the circumferential direction of the stator core 10, the circumferential size of the cooling hole 12d of the fourth punching plate 1d is larger than the circumferential size of the cooling hole 12c of the third punching plate 1c. Along the radial direction of the stator core 10, the radial size of the cooling hole 12d of the fourth punching plate 1d is larger than the radial size of the cooling hole 12c of the third punching plate 1c.

[0091] In combination with Figures 14a and 14b, Figure 15 shows a partial structure of the stator core 10. As shown in Figure 15, along the axial direction of the stator core 10, the first punch 1a, the second punch 1b, the fourth punch 1d and the third punch 1c are arranged adjacent to each other in sequence, and the cooling hole 12d of the fourth punch 1d can connect the cooling hole 12b of one second punch 1b with at least one cooling hole 12c of the third punch 1c. The circumferential size of the cooling hole 12d of the fourth punch 1d can be greater than the spacing between two adjacent cooling holes 12b of the second punch 1b, so that one cooling hole 12d of the fourth punch 1d can be connected to the two cooling holes 12b of the second punch 1b at the same time. The circumferential size of the cooling hole 12d of the fourth punch 1d can be greater than the spacing between two adjacent cooling holes 12c of the third punch 1c, so that one cooling hole 12d of the fourth punch 1d can be connected to the two cooling holes 12c of the third punch 1c at the same time.

[0092] Figure 16 shows a schematic cross-sectional view of the partial structure of the housing 50 and the stator core 10 of the motor 100. As shown in Figure 16, for example, a cooling medium is introduced into the liquid inlet 101 of the motor 100, and the cooling medium enters the radial groove 52 of the housing 50 through the liquid inlet pipe 51 of the housing 50 and flows in the radial groove 52 along the circumference of the stator core 10, and then enters the multiple cooling holes 12c on the outer peripheral surface of the third punch 1c. The cooling medium in each cooling hole 12c flows along the axial direction of the stator core 10 to the cooling holes 12d of the fourth punch 1d on both sides of the third punch 1c. The cooling medium in each cooling hole 12d can pass through the cooling channel formed by the multiple cooling holes 12b of the multiple second punches 1b and flow to the cooling hole 12a of the first punch 1a and spray out and drip on the end of the stator winding 20. Since the cooling hole 12a of the first punch 1a is offset relative to the cooling hole 12b of the adjacent second punch 1b in at least one of the circumferential or radial directions of the stator core 10, the cross-sectional size of the channel for the circulation of the cooling medium is reduced, so that the cooling medium ejected from the cooling hole 12a of the first punch 1a has a higher speed.

[0093] In some embodiments, the cooling holes 12d of the fourth punch 1d can be realized in the form of two circumferential connections or multiple circumferential connections. Along the circumference of the stator core 10, at least two adjacent cooling holes 12d among the multiple cooling holes 12d of the fourth punch 1d are connected. In the fourth punch 1d with this structure, the cooling holes 12d of the fourth punch 1d can be simultaneously connected to the cooling holes 12b of the multiple second punches 1b and the cooling holes 12c of the multiple third punches 1c. When the cooling medium in the multiple cooling holes 12 of the third punch 1c flows into the cooling hole 12d of the same fourth punch 1d, the cooling medium can flow in the cooling hole 12d along the circumference of the stator core 10, thereby flowing to the multiple cooling holes 12b of the second punch 1b.

[0094] In the stator core 10 having the fourth punch 1d, the cooling hole 12d of the fourth punch 1d can guide the cooling medium in the third punch 1c to the cooling hole 12b of the second punch 1b which is closer to the center of the stator core 10, making it easier to guide the cooling medium to the end winding. When the cooling hole 12d of the fourth punch 1d is larger in size, the cooling hole 12d of the fourth punch 1d can form a collection space between the second punch 1b and the third punch 1c that can accommodate more cooling medium. The cooling medium is collected here to provide a more sufficient oil supply to the liquid outlet 102, ensuring the oil pressure and oil speed ejected from the liquid outlet 102. In addition, the setting of the fourth punch 1d makes it unnecessary for the cooling hole 12b of the second punch 1b and the cooling hole 12c of the third punch 1c to strictly correspond along the axial direction of the stator core 10, reducing the assembly precision requirements.

[0095] Figure 17 shows an exploded view of a stator core 10, in which the fourth punch 1d is annular, and the distance from the outer circumference of the fourth punch 1d to the center is less than the distance from the outer circumference of the second punch 1b to the center and the distance from the outer circumference of the third punch 1c to the center. The center hole 11 of the second punch 1b, the center hole 11 of the third punch 1c, and the center hole 11 of the fourth punch 1d coincide along the axial projection of the stator core 10. It can also be considered that the distance from the outer circumference of the fourth punch 1d to the center hole 11 is less than the distance from the outer circumference of the second punch 1b to the center hole 11 and the distance from the outer circumference of the third punch 1c to the center hole 11. The fourth punch 1d of this structure is a structure in which the multiple cooling holes 12d of the fourth punch 1d shown in Figure 13b are connected along the circumference of the stator core 10. At this time, the cooling holes 12d can be considered to disappear after being connected. The fourth punch 1d can be arranged and fixed between the second punch 1b and the third punch 1c by bonding.

[0096] Figure 18a shows the structure of the second punching plate 1b and the fourth punching plate 1d arranged and stacked. Along the axial direction of the stator core 10, the orthographic projection of the outer circumference of the fourth punching plate 1d on the second punching plate 1b is located between the cooling hole 12b of the second punching plate 1b and the bottom of the punching groove 13.

[0097] Figure 18b shows the structure of the third punching plate 1c and the fourth punching plate 1d arranged and stacked. Along the axial direction of the stator core 10, the orthographic projection of the outer peripheral surface of the fourth punching plate 1d on the third punching plate 1c is located between the cooling hole 12c of the third punching plate 1c and the groove bottom of the punching plate groove 13.

[0098] Based on the structure shown in Figures 18a and 18b, when the fourth punch 1d is arranged between the second punch 1b and the third punch 1c, an annular channel surrounding the circumference of the stator core 10 can be formed between the surface of the third punch 1c facing the second punch 1b, the outer peripheral surface of the fourth punch 1d, and the surface of the second punch 1b facing the third punch 1c. This annular channel can allow the cooling medium to flow along the circumference of the stator core 10. All cooling holes 12c of the third punch 1c are connected to the annular channel, and all cooling holes 12b of the second punch 1b are also connected to the annular channel. The cooling medium can enter the annular channel through the cooling holes 12c of the third punch 1c, flow along the circumference of the stator core 10, and then be transported to each cooling hole 12b of the second punch 1b.

[0099] In some embodiments, when the cooling medium can flow along the circumference of the stator core 10, when the first punch 1a is the stator punch 1 at the axial end of the stator core 10 and is used for oil spraying, the number of cooling holes 12a of the first punch 1a can be reduced, so that a part of the cooling medium cannot be sprayed out from certain cooling holes 12a of the first punch 1a, and can only flow along the circumference of the stator core 10 to the cooling holes 12a at other positions of the first punch 1a for spraying, thereby further improving the spraying speed.

[0100] In some embodiments, the structure of the fourth punch 1d can be omitted. Specifically, the stator core 10 includes a plurality of stator punches 1 including a first punch 1a, a second punch 1b and a third punch 1c. Along the axial direction of the stator core 10, the third punch 1c is arranged adjacent to the above-mentioned other second punch 1b-2. That is to say, the third punch 1c is arranged on the side of the plurality of second punches 1b away from the first punch 1a, and it can be considered that the plurality of second punches 1b are arranged between the first punch 1a and the third punch 1c. Specifically, along the radial direction of the stator core 10, the cooling hole 12 of the third punch 1c is connected to the outer peripheral surface of the third punch 1c, and it can be considered that the cooling hole 12 of the third punch 1c is at least a part of the axial groove 106 of the stator core 10. Along the axial direction of the stator core 10, the plurality of cooling holes 12c of the third punch 1c are respectively used to connect the plurality of cooling holes 12b of the second punch 1b adjacent to the third punch 1c. The distance between the cooling hole 12c of the third punching plate 1c and the center of the third punching plate 1c is greater than or equal to the distance between the cooling hole 12b of the second punching plate 1b and the center of the second punching plate 1b. The center holes 11 of the second punching plate 1b and the third punching plate 1c coincide with each other in the axial projection along the stator core 10. It can also be considered that the distance between the cooling hole 12c of the third punching plate 1c and the center hole 11 of the third punching plate 1c is greater than or equal to the distance between the cooling hole 12b of the second punching plate 1b and the center hole 11 of the second punching plate 1b.

[0101] In summary, the stator core 10 of the motor 100 provided in the embodiment of the present application does not require an oil spray ring structure, and the cooling medium can be sprayed to the end winding at the axial end of the stator core 10 through the cooling channel of the stator core 10 itself. The first punching sheet 1a is used as the stator punching sheet 1 at the end of the stator core 10, and the staggered arrangement of the cooling holes 12a of the first punching sheet 1a and the cooling holes 12b of the second punching sheet 1b makes the cooling medium have a higher speed when spraying, thereby achieving a good liquid cooling and heat dissipation effect. In some embodiments, compared with traditional oil cooling and heat dissipation, the stator core 10 of the motor 100 provided in the embodiment of the present application has a lower temperature and a better heat dissipation effect. The oil spray ring is omitted from the structure, which further reduces the cost of the motor 100 and achieves the effect of reducing costs and increasing efficiency.

[0102] The above are only specific embodiments of the present application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A stator core for cooling the end of a winding, characterized in that, The stator core includes a plurality of stator punching sheets. Each stator punching sheet includes a central hole penetrating the stator punching sheet along the axial direction of the stator core and a plurality of cooling holes. The plurality of cooling holes are arranged at intervals along the circumferential direction of the stator punching sheet. Each cooling hole is arranged at intervals between the central hole and the outer peripheral surface of the stator punching sheet. The plurality of stator punching sheets include a first punching sheet and a second punching sheet, where: Along the axial direction of the stator core, the first punching sheet and the second punching sheet are arranged adjacent to each other. The central hole of the first punching sheet communicates with the central hole of the second punching sheet. Each cooling hole of the first punching sheet is used to communicate with a cooling hole of the second punching sheet and to cool the end part of the stator winding; Along at least one of the radial direction or the circumferential direction of the stator core, each cooling hole of the first punching sheet is eccentrically arranged relative to a cooling hole of the second punching sheet communicated therewith.

2. The stator core according to claim 1, characterized in that, Along the radial direction of the stator core, the distance between the cooling hole and the central hole of the first punching sheet is smaller than the distance between the cooling hole and the central hole of the second punching sheet.

3. The stator core according to claim 1 or 2, characterized in that, A cooling hole of the first punching sheet communicates with a cooling hole of the second punching sheet, and another cooling hole of the first punching sheet communicates with another cooling hole of the second punching sheet; Along the circumferential direction of the stator core, the distance between one cooling hole and another cooling hole of the first punching sheet is not equal to the distance between one cooling hole of the second punching sheet and another cooling hole of the first punching sheet, and the distance between one cooling hole and another cooling hole of the second punching sheet is not equal to the distance between one cooling hole of the first punching sheet and another cooling hole of the second punching sheet.

4. The stator core according to claim 1, characterized in that, The aperture of the cooling hole of the first punching sheet is less than or equal to the aperture of the cooling hole of the second punching sheet.

5. The stator core according to claim 1, wherein, The number of cooling holes of the first punching sheet is less than the number of cooling holes of the second punching sheet.

6. The stator core according to any one of claims 1-5, characterized in that, The plurality of stator punching sheets include a plurality of second punching sheets and another second punching sheet. The plurality of second punching sheets are arranged between the second punching sheet and the another second punching sheet along the axial direction of the stator core; Along the axial direction of the stator core, the plurality of cooling holes of the second punching sheet are respectively used to communicate with the plurality of cooling holes of the adjacent second punching sheets. The plurality of cooling holes of the another second punching sheet are respectively used to communicate with the plurality of cooling holes of the adjacent second punching sheets. Each of the plurality of cooling holes of each second punching sheet in the plurality of second punching sheets is respectively used to communicate with the plurality of cooling holes of the adjacent second punching sheets.

7. The stator core according to claim 6, wherein For two circumferentially adjacent cooling holes of the second punching sheet, the distance between one cooling hole and the central hole is greater than the distance between the other cooling hole and the central hole.

8. The stator core according to claim 7, wherein, Between any two connected cooling holes of the second punching sheets, along the radial direction of the stator core, the distance between one cooling hole and the center hole is greater than the distance between another cooling hole and the center hole.

9. The stator core according to claim 7 or 8, characterized in that, The plurality of stator punching sheets include a third punching sheet, and the third punching sheet is arranged adjacent to the other second punching sheet along the axial direction of the stator core, wherein: Along the radial direction of the stator core, the cooling hole of the third punching sheet is connected with the outer peripheral surface of the third punching sheet; Along the axial direction of the stator core, the multiple cooling holes of the third punching sheet are respectively used to communicate with the multiple cooling holes of the other second punching sheet.

10. The stator core according to claim 7 or 8, characterized in that, The plurality of stator punching sheets include a third punching sheet and a fourth punching sheet, the fourth punching sheet is arranged adjacent to the other second punching sheet along the axial direction of the stator core, and the third punching sheet is arranged adjacent to the side of the fourth punching sheet away from the other second punching sheet along the axial direction of the stator core, wherein: Along the radial direction of the stator core, the cooling hole of the third punching sheet is connected with the outer peripheral surface of the third punching sheet; Along the axial direction of the stator core, the plurality of cooling holes of the fourth punching sheet are respectively used to connect at least one cooling hole of the other second punching sheet with at least one cooling hole of the third punching sheet.

11. The stator core according to claim 10, wherein Along the circumferential direction of the stator core, a circumferential dimension of the cooling hole of the fourth punching plate is larger than a distance between two adjacent cooling holes of the second punching plate and a distance between two adjacent cooling holes of the third punching plate.

12. The stator core according to claim 10 or 11, characterized in that, Each of the cooling holes of the fourth punching sheet is connected to the outer peripheral surface of the fourth punching sheet along the radial direction of the stator core; Along the circumferential direction of the stator core, at least two adjacent cooling holes among the plurality of cooling holes of the fourth punching sheet are connected.

13. A motor, characterized in that, The motor comprises a housing and a stator core as claimed in any one of claims 1 to 12; The housing is sleeved on the outer peripheral surface of the stator core, and the housing comprises a coolant inlet, which is used to communicate with at least one cooling hole of the second punching sheet.

14. A powertrain, characterized in that, It comprises a reducer or a transmission and the motor as claimed in claim 13, wherein the motor shaft of the motor is drivingly connected to the input shaft of the reducer or the input shaft of the transmission.

15. An electric vehicle, characterized in that, The invention comprises a wheel, a transmission mechanism and a power assembly as claimed in claim 14, wherein the power assembly drives the wheel through the transmission mechanism.

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