Motor cooling system, motor, electric drive assembly system and vehicle

Abstract

The invention relates to an electric machine cooling system. The motor cooling system comprises a rotor and a stator, the stator comprises a stator iron core and a winding, the stator iron core is provided with an annular receiving groove at the periphery and used for receiving oil supplied by an oil pump, the stator is provided with a first channel for conveying the oil from the receiving groove to the two ends of the stator, and the first channel is communicated with the winding. The motor cooling system further comprises an isolation sleeve used for isolating the rotor from the stator, and the isolation sleeve is provided with a sealing structure at the driving end of the motor, so that the oil is conveyed from the driving end of the motor to the non-driving end of the motor. The present disclosure also relates to an electric machine comprising such an electric machine cooling system, an electric drive assembly system comprising such an electric machine, and a vehicle comprising such an electric drive assembly system.

Description

Technical Field

[0001] This disclosure relates to an electric motor cooling system. This disclosure also relates to an electric motor including such a cooling system, an electric drive assembly system including such an electric motor, and a vehicle including such an electric drive assembly system. Background Technology

[0002] Motors used to drive vehicles typically have high power and generate a significant amount of heat during continuous operation. If heat dissipation is insufficient, this heat will accumulate inside the motor, causing its temperature to rise and affecting its reliability and performance.

[0003] Existing motor cooling methods include oil cooling. Oil cooling cools the stator and rotor using cooling oil, and while it has strong heat dissipation capabilities, the increased power consumption due to oil churning losses results in low overall efficiency. Therefore, existing technologies propose a method to avoid oil churning losses: isolating the stator and rotor with an isolation sleeve.

[0004] The stator consists of an iron core and windings. The stator windings are coils that generate a magnetic field when energized, and are also the main source of heat inside the motor. When the motor runs, the stator windings are excited by the current, and their temperature gradually rises; the stator core transfers heat through conduction and is also affected by the heat from the stator windings, thus the stator temperature also rises. When the stator core temperature is too high, it can damage the motor's insulation, thereby affecting the motor's lifespan and safety. The places on the stator where the windings pass through are called slots, the places that separate the slots are called teeth, and the part that connects all the teeth is called the yoke (the area formed between the bottom of the stator lamination slots and the outer circumference). The yoke of the stator is also a region where heat generation is most severe.

[0005] Therefore, there is a need for a motor cooling system that can simultaneously and adequately cool the stator windings and yoke while avoiding oil churning losses. Summary of the Invention

[0006] Therefore, this disclosure aims to solve the above problems and its purpose is to provide a novel motor cooling system, motor, electric drive assembly system and vehicle.

[0007] The objective is achieved by an electric motor cooling system according to an embodiment of the present disclosure, comprising: a rotor and a stator, the stator including a stator core and windings, the stator core having an annular receiving groove on its outer periphery for receiving oil supplied from an oil pump, the stator having a first channel for conveying the oil from the receiving groove to both ends of the stator, the electric motor cooling system further including an isolation sleeve for isolating the rotor and the stator, the isolation sleeve having a sealing structure at the drive end of the motor, such that the oil is conveyed from the drive end of the motor to the non-drive end of the motor.

[0008] In the motor cooling system according to this disclosure, the stator and rotor are isolated by an isolation sleeve, which avoids oil churning losses, and the cooling oil can directly cool the stator yoke and windings and fully wet the winding ends, resulting in better heat dissipation and better motor performance and efficiency.

[0009] The motor cooling system according to this disclosure may also have one or more of the following features, individually or in combination.

[0010] According to one embodiment of this disclosure, the isolation sleeve further includes an axially extending body structure that extends from the sealing structure to an end cap at the non-driving end of the motor.

[0011] According to one embodiment of this disclosure, the first channels are circumferentially spaced and are in fluid communication with the receiving tank.

[0012] According to one embodiment of the present disclosure, the stator core includes two first lamination sections arranged axially and a second lamination section disposed between the two first lamination sections.

[0013] According to one embodiment of this disclosure, the receiving slot is disposed on the second stacked section.

[0014] According to one embodiment of this disclosure, at least a portion of the first channel is disposed on the first stacked section.

[0015] According to one embodiment of this disclosure, the stator core further includes an end lamination section disposed on the side opposite to the axial direction of each of the two first lamination sections, and at least a portion of the first channel is disposed on the end lamination section.

[0016] According to one embodiment of this disclosure, the first laminated section and the end laminated section are provided with a plurality of bolt holes along the circumferential direction for fasteners to pass through.

[0017] According to one embodiment of this disclosure, the sealing structure of the isolation sleeve is provided with a plurality of bolt holes, and the first lamination section near the drive end of the motor and the end lamination section are fixed together with the isolation sleeve by the fasteners.

[0018] According to one embodiment of this disclosure, the stator is further provided with a second channel for conveying the oil from the receiving tank to the non-drive end of the motor, at least a portion of the second channel passing through the bolt hole.

[0019] According to one embodiment of this disclosure, the stator core is provided with a plurality of stator slots along the circumferential direction, and slot windings are inserted into the stator slots. The oil flows from the driving end of the motor to the non-driving end of the motor through the stator slots of the stator core.

[0020] According to one embodiment of this disclosure, the motor cooling system further includes a housing, and the oil flows from the non-driving end of the motor into an oil collector through an oil outlet on the housing.

[0021] This disclosure also relates to an electric motor that includes the electric motor cooling system described above.

[0022] This disclosure also relates to an electric drive assembly system that includes the motor described above.

[0023] This disclosure also relates to a vehicle that includes the electric drive assembly system described above. Attached Figure Description

[0024] The above and other features and advantages of this disclosure will become more apparent from the following detailed description of exemplary embodiments taken in conjunction with the accompanying drawings, which are for illustrative purposes only and are not intended to limit the scope of this disclosure in any way. The following drawings are not intentionally drawn to scale with actual dimensions; their focus is on illustrating the gist of this disclosure.

[0025] Figure 1 An assembled motor is shown, which includes a motor cooling system according to one embodiment of the present disclosure;

[0026] Figure 2 yes Figure 1 The axial sectional view of the motor shown;

[0027] Figure 3 yes Figure 1 An exploded view of the motor shown;

[0028] Figure 4A An isolation sleeve according to one embodiment of the present disclosure is shown;

[0029] Figure 4B An isolation sleeve according to another embodiment of the present disclosure is shown;

[0030] Figure 5 The stator of the motor is shown;

[0031] Figure 6 This is a partial axial sectional view of the stator;

[0032] Figure 7A The laminations in the second lamination section of the stator are shown. Figure 7B This is a detailed view of a portion of the stacked sheets;

[0033] Figure 8A The laminations in the first lamination section of the stator are shown. Figure 8B This is a detailed view of a portion of the stacked sheets;

[0034] Figure 9A The laminations in the end lamination section of the stator are shown. Figure 9B This is a detailed view of a portion of the stacked sheets. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings.

[0036] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The use of words such as “a,” “an,” or “the” in this patent application specification and claims does not indicate a limitation of quantity, but rather indicates the presence of at least one. Words such as “comprising” or “including” mean that the element or object preceding the word encompasses the element or object listed following the word and its equivalents. Words such as “connected” or “linked” are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. Terms such as “up,” “down,” “left,” and “right” are used only to indicate relative positional relationships, which may change accordingly when the absolute position of the described object changes. The terms “axial” and “axial direction” refer to the direction of the rotation axis of the motor.

[0037] For ease of description, the accompanying drawings of this disclosure have correspondingly simplified or omitted components commonly used in the art, such as external connecting lines and other components unrelated to the description of this disclosure. These omitted or simplified components do not affect a person skilled in the art's understanding of the content of this disclosure.

[0038] Figure 1 An assembled motor 100 is shown according to an exemplary embodiment of the present disclosure. Figure 2 An axial sectional view of the motor 100 is shown. Figure 3 An exploded view of the motor 100 is shown. As shown, the motor 100 includes a housing 40, a rotor 10 housed within the housing 40, a stator 20, and an isolation sleeve 30. The isolation sleeve 30 is installed between the rotor 10 and the stator 20 to isolate the rotor 10 and the stator 20. Specifically, the isolation sleeve 30 is installed on the inner ring of the stator 20 and does not contact the rotor 10.

[0039] The isolation sleeve 30 separates the rotor 10 and the stator 20, preventing the cooling oil from flowing into the motor air gap and contacting the rotor, thus avoiding oil churning losses.

[0040] refer to Figure 4A The isolation sleeve 30 is provided with a sealing structure 31 and an axially extending main body structure 32, which extends from the sealing structure 31 to the end cap 44 at the non-drive end of the motor and abuts against the end cap 44. For example, the sealing structure 31 and the main body structure 32 can be integrally formed. A sealing ring 34 is also provided on the sealing structure 31 to prevent cooling oil from flowing out of the sealing structure 31.

[0041] It should be noted that this disclosure does not limit the shape of the main structure 32 of the isolation sleeve 30. For example, the main structure 32 can also be as follows: Figure 4B As shown. Reference Figure 4B In addition to the axially extending portion, the main structure 32 also includes an arc-shaped extension portion 33, which extends to the end cover 44 of the non-drive end of the motor and abuts against the end cover 44.

[0042] Figure 5 The stator 20 of the motor is shown. Figure 6 A partial axial sectional view of the stator 20 is shown. (Reference) Figure 5 and Figure 6 The stator 20 includes a stator core 201 and windings 202. The stator core 201 is composed of multiple stacked laminations, which can be divided into multiple lamination segments. The stator core 201 of the stator 20 is provided with circumferentially arranged stator slots 28 located radially inward and radially outward protruding lugs 29. The windings 202 are inserted into the stator slots 28 for retaining and separating the windings 202 of the stator 20. The windings 202 extend axially in the stator slots 28 of the stator core 201 and have winding ends 203 extending beyond the stator core 201. Figure 6 In the stator core 201, the stator core 201 includes an end lamination section 26, a first lamination section 24, and a second lamination section 25 along the axial direction. It is understood that the stator core 201 also includes a first lamination section 24 and an end lamination section 26 on the other side of the second lamination section 25 along the axial direction. Lugs 29 engage with positioning grooves on the inner surface of the housing 40 to position the stator core 201 of the stator 20 in the circumferential direction. Apart from the lugs 29 and stator toothed grooves 28 described above, as will be described in detail below, the laminations of each lamination section of the stator 20 have the same structure, while the lamination structures between different lamination sections may be different.

[0043] For example, the motor 100 may be a drive motor for driving a vehicle, wherein a large alternating current flows through the winding 202 of the drive motor to generate an alternating magnetic field that causes the rotor 10 of the drive motor to rotate around the motor's rotation axis X. The stator core 201 is subjected to the alternating magnetic field, generating hysteresis losses and eddy current losses. Therefore, the winding 202 and stator core 201 of the stator 20 are the main heat-generating components of the motor 100 and require cooling. For this purpose, the motor 100 is provided with a motor cooling system to cool the winding 202 and stator core 201 of the stator 20. The motor cooling system may, for example, cool the internal parts of the motor 100 using cooling oil.

[0044] For this purpose, the motor cooling system includes an oil pump 41, an oil supply pipe 42, a channel inside the housing 40, and an oil collector 43. The cooling oil circulating in the motor cooling system can be pumped from the oil collector 43 through the oil supply pipe 42 by the oil pump 41 to the housing 40 of the motor 100, flows through the channel inside the housing 40 to cool the internal components of the motor, then collects at the bottom of the housing 40, and flows back into the oil collector 43, which is in fluid communication with the housing 40.

[0045] Specifically, the oil pipe 42 passes through the housing 40 and leads to the annular receiving groove 21 located in the axial middle portion of the stator 20. This receiving groove 21 is formed by the second lamination section 25. (See reference) Figure 5 and Figure 6 The outer diameter of the second lamination section 25 is smaller than the outer diameter of the first lamination section 24, thus forming an annular receiving groove 21 under the clamping of the two first lamination sections 24. Accordingly, the stator 20 receives oil pumped by the oil pump 41 through the oil supply pipe 42 through the receiving groove 21, and this oil can then be used to cool the stator 20.

[0046] After being received by the receiving tank 21, the oil flows along different paths on the stator 20. For example... Figure 6 As shown, a first channel 22, which is in fluid communication with the receiving groove 21, is provided on the stator core 201 of the stator 20. Thus, oil received by the receiving groove 21 can flow through this first channel 22 and be transported to the end of the stator 20. Figure 6 As shown, the first channel 22 is relatively close to the radial interior of the stator core 201, that is, close to the stator slot 28 of the stator core 201. The first channel 22 is provided on the lamination section other than the second lamination section 25 that forms the receiving slot 21.

[0047] refer to Figure 8A and Figure 8BThe laminations in the first lamination section 24 are provided with lamination holes 241, which form a portion of the first channel 22 in the first lamination section 24. Specifically, the lamination hole 241 consists of an outer section 241a and an elongated inner section 241b. The outer section 241a of the lamination hole 241 communicates with the receiving groove 21 through its radially outer portion, allowing oil to flow into the lamination hole 241. The inner section 241b of the lamination hole 241, particularly its radially inner portion, is close to the stator slot 28, thereby cooling the winding 202 within the stator slot 28.

[0048] refer to Figure 9A and Figure 9B The laminations in the end lamination section 26 are provided with elongated oval end holes 261. These end holes 261 are axially aligned with the radially inner portion of the lamination holes 241, forming a portion of the first channel 22 in the end lamination section 26. Oil flowing in the lamination holes 241 can be sprayed onto the winding end 203 of the winding 202 through the end holes 261 to cool the winding end 203. The area of ​​the end holes 261 is significantly smaller than that of the lamination holes 241, which helps to increase the flow rate of oil sprayed from the end holes 261 and increase the proportion of oil sprayed onto the winding end 203.

[0049] The aforementioned lamination hole 241 and end hole 261 are both located at the yoke of the laminations of the stator core 201, that is, in the top region of the winding 202 near the stator slot 28. This region is a high-heat area, and the present disclosure allows for direct cooling of the stator yoke with cooling oil.

[0050] refer to Figure 2 The isolation sleeve 30 has a sealing structure 31 at the drive end of the motor, which can cover the winding end 203. Therefore, after the cooling oil cools the winding end 203, the cooling oil is blocked by the sealing structure 31, preventing it from flowing out from the gaps in the winding end 203, thus fully wetting the winding end 203, and then flowing from the drive end of the motor to the non-drive end of the motor through the pressure difference. The isolation sleeve 30 extends to the end cap 44 of the non-drive end of the motor. After the cooling oil flows to the non-drive end of the motor and cools the winding end 203 at the non-drive end, the oil collects at the bottom of the housing 40 and flows into the oil collector 43 through the oil outlet on the housing 40. (Reference) Figures 7A-9BHarmonic holes 281 are also provided between the stator slots 28 on the stator core 201 laminations. To prevent cooling oil from leaking out at the openings of the stator slots 28 and harmonic holes 281 and flowing radially towards the rotor, an isolation sleeve 30 is used to cooperate with the inner wall of the stator core 201 to isolate the rotor 20 and the stator 10, thereby ensuring that the cooling oil can only flow axially. When the cooling oil flows from the drive end of the motor to the non-drive end, it passes through the stator slots 28 on the stator core 201 to directly cool the windings 202 inside the stator slots 28, and passes through the harmonic holes 281 on the stator core 201, thereby quickly carrying away heat.

[0051] In addition to the first channel 22, the stator 20 is also provided with a second channel 23 in fluid communication with the receiving tank 21 to transport oil from the receiving tank 21 to the non-drive end of the motor. (See reference) Figures 8A-9B The first lamination section 24 and the end lamination section 26 are provided with a number of bolt holes 27 for fasteners to pass through at the position of the lug 29, and the sealing structure 31 of the isolation sleeve 30 is correspondingly provided with a number of bolt holes 27 (see Figure 4A The first lamination section 24 and the end lamination section 26 near the drive end of the motor are fixed to the isolation sleeve 30 by fasteners. The bolt holes 27 of the first lamination section 24 and the end lamination section 26 near the non-drive end of the motor communicate with the receiving groove 21, allowing oil to flow into the bolt holes 27. The oil flowing in the bolt holes 27 can be sprayed onto the winding end 203 of the winding 202 to cool it. After cooling the winding end 203, the oil collects at the bottom of the housing 40 and flows into the oil collector 43. At the bottom of the housing 40 and in the oil collector 43, the oil flowing through the first channel 22 and the oil flowing through the second channel 23 are thoroughly mixed.

[0052] Figure 2 What is shown is Figure 4A The isolation sleeve shown in this embodiment ensures that both the drive and non-drive winding ends 203 of the motor are fully wetted and cooled. If using... Figure 4B The isolation sleeve shown only allows the winding end 203 of the motor drive end to be fully wetted and cooled.

[0053] According to another aspect of this disclosure, an electric drive assembly system is proposed, which includes the motor as described above. It should be understood that the electric drive assembly system of this disclosure also possesses the advantages described above regarding the motor cooling system.

[0054] According to another aspect of this disclosure, a vehicle is proposed that includes the electric drive powertrain system as described above. The vehicle can be an electrified vehicle, such as a battery electric vehicle (BEV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), a range-extended electric vehicle (REEV), or a fuel cell electric vehicle (FCEV). The vehicle can also be a hydrogen fuel cell vehicle. It should be understood that the vehicle of this disclosure also possesses the advantages described above regarding the motor cooling system.

[0055] Certain features, structures, or characteristics in one or more embodiments of this disclosure may be appropriately combined.

[0056] The foregoing description is illustrative of the present disclosure and should not be construed as limiting it. While several exemplary embodiments of the present disclosure have been described, those skilled in the art will readily understand that many modifications may be made to the exemplary embodiments without departing from the novel teachings and advantages of the present disclosure. Therefore, all such modifications are intended to be included within the scope of the present disclosure as defined in the claims. It should be understood that the foregoing description is illustrative of the present disclosure and should not be construed as limiting it to the specific embodiments disclosed, and modifications to the disclosed embodiments and other embodiments are intended to be included within the scope of this disclosure.

Claims

1. A motor cooling system, characterized in that, The motor cooling system includes a rotor (10) and a stator (20). The stator (20) includes a stator core (201) and windings (202). The stator core (201) has an annular receiving groove (21) on its outer periphery for receiving oil supplied from the oil pump (41). The stator (20) is provided with a first channel (22) for transporting the oil from the receiving groove (21) to both ends of the stator (20). The motor cooling system further includes an isolation sleeve (30) for separating the rotor (10) and the stator (20). The isolation sleeve (30) has a sealing structure (31) at the drive end of the motor, so that the oil is delivered from the drive end of the motor to the non-drive end of the motor.

2. The motor cooling system according to claim 1, characterized in that, The isolation sleeve (30) also includes an axially extending main body structure (32) that extends from the sealing structure (31) to the end cap (44) of the non-driving end of the motor.

3. The motor cooling system according to claim 1, characterized in that, The first channel (22) is distributed circumferentially and is in fluid communication with the receiving slot (21).

4. The motor cooling system according to claim 1, characterized in that, The stator core (201) includes two first lamination sections (24) arranged along the axial direction and a second lamination section (25) arranged between the two first lamination sections.

5. The motor cooling system according to claim 4, characterized in that, The receiving slot (21) is disposed on the second stacked section (25).

6. The motor cooling system according to claim 4, characterized in that, At least a portion of the first channel (22) is disposed on the first stacked section (24).

7. The motor cooling system according to claim 4, characterized in that, The stator core (201) further includes an end lamination section (26) arranged on the side opposite to the axial direction of the second lamination section (25) of each of the two first lamination sections (24), and at least a portion of the first channel (22) is disposed on the end lamination section (26).

8. The motor cooling system according to claim 7, characterized in that, The first lamination section (24) and the end lamination section (26) are provided with a plurality of bolt holes (27) for fasteners to pass through in the circumferential direction.

9. The motor cooling system according to claim 8, characterized in that, The sealing structure (31) of the isolation sleeve (30) is provided with a number of bolt holes (27), and the first lamination section (24) near the drive end of the motor and the end lamination section (26) are fixed together with the isolation sleeve (30) by the fasteners.

10. The motor cooling system according to claim 8, characterized in that, The stator is also provided with a second channel (23) for conveying the oil from the receiving tank (21) to the non-driving end of the motor, at least a portion of the second channel (23) passing through the bolt hole (27).

11. The motor cooling system according to claim 1, characterized in that, The stator core (201) is provided with a plurality of stator slots (28) arranged circumferentially. The winding (202) is inserted into the stator slots (28). The oil flows from the driving end of the motor to the non-driving end of the motor through the stator slots (28) of the stator core.

12. The motor cooling system according to claim 1, characterized in that, The motor cooling system also includes a housing (40), through which the oil flows into an oil collector (43) via an oil outlet on the housing (40).

13. An electric motor (100) comprising an electric motor cooling system according to any one of claims 1 to 12.

14. An electric drive assembly system comprising the motor (100) according to claim 13.

15. A vehicle comprising the electric drive assembly system according to claim 14.

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