An oil-cooled electric machine

Abstract

The application discloses an oil-cooled motor, which comprises a casing, a stator core fixed in the casing, a stator winding installed on the stator core, and a rotor rotatably sleeved in the stator core; an inner wall of the casing is provided with a casing oil inlet channel; a first cooling oil channel is arranged on the outer side of the yoke of the first stator lamination group in the circumferential direction; an inner ring of the first stator lamination group is provided with a first stator core slot; and the first stator core slot is provided with a first axial cooling oil channel. The casing oil inlet channel is communicated with the first cooling oil channel, the first axial cooling oil channel and an annular oil channel. The application integrates multiple cooling oil channels in the interior of the stator core; the integrated oil channel in the interior of the stator core slot is used for guiding the cooling oil into the branch oil channels in the stator core slot; the cooling oil flows to the two end faces of the stator core in the branch oil channels in the stator core slot; the winding in the slot is directly cooled; and the overall cooling effect is greatly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric machines, and particularly relates to an oil-cooled electric machine of a new energy vehicle. BACKGROUND

[0002] With the continuous pursuit of the performance of the new energy vehicle by the users, the vehicle enterprises have higher and higher requirements on the torque, power density and efficiency of the driving electric machine. The increase of the power of the electric machine and the improvement of the power density make the heat problem of the electric machine most prominent.

[0003] How to limit the temperature rise limit in the electric machine within the allowable range through effective cooling is an important factor to guarantee the torque / power density of the electric machine. The existing cooling methods of the new energy vehicle electric machine mainly include water cooling and oil cooling.

[0004] The water cooling cannot directly cool the heat source, and is prone to form a local thermal island, so that the heat dissipation efficiency is not ideal, and the further improvement of the power density of the electric machine is limited. With the increasing power of the electric machine, the oil-cooled electric machine as a direct cooling technology has attracted more and more attention. Since the oil itself is not magnetically conductive and electrically conductive, the heat transfer method of directly contacting the cooling oil with the heat generating components greatly improves the heat transfer effect, and greatly improves the power density of the electric machine.

[0005] The existing oil cooling technology can be divided into stator cooling and rotor cooling according to the structure of the electric machine. Among them, the rotor oil cooling introduces an additional rotor oil stirring loss, which is prone to cause uneven heat dissipation in the electric machine, and affects the overall cooling effect. At present, the existing stator cooling is mainly the oil spraying method for cooling the stator end winding. The cooling of the stator core is generally to cool the outer surface of the stator core or to arrange a cooling oil channel in the stator core, so as to indirectly cool the winding in the slot of the stator core. Due to the long heat conduction path, the cooling effect is poor. It is easy to make the heat concentrated in the middle section of the stator core, so that the axial middle winding of the electric machine cannot be effectively heat managed. SUMMARY

[0006] The purpose of the present application is to solve the problems in the prior art, and to provide an oil-cooled electric machine which can well solve the heat dissipation problems of the winding in the slot of the stator, the end winding and the stator core, and greatly improve the heat dissipation performance of the electric machine.

[0007] The technical scheme of the present application is as follows: an oil-cooled electric machine, comprising a machine shell, a stator core fixed in the machine shell, a stator winding installed on the stator core, and a rotor rotatably sleeved in the stator core.

[0008] Characterized in that: an inner wall of the machine shell is provided with a machine shell oil inlet channel.

[0009] The stator core comprises at least one first stator lamination group and a second stator lamination group with an outer diameter smaller than that of the first stator lamination group; the first stator lamination group is arranged at both ends of the second stator lamination group.

[0010] Further, the outer side of the yoke of the first stator lamination group is provided with a first cooling oil channel in the circumferential direction, and the inner ring of the first stator lamination group is provided with a first stator core slot, and the first stator core slot is provided with a first axial cooling oil channel.

[0011] Further, the outer circle of the second stator lamination group is provided with an annular oil channel.

[0012] Further, the oil inlet channel of the casing is communicated with the first cooling oil channel, the first axial cooling oil channel and the annular oil channel.

[0013] Preferably, the first stator lamination group is composed of at least two first stator laminations, the second stator lamination group is composed of at least two second stator laminations, and the second stator lamination group is symmetrically arranged at the middle position of the first stator lamination group.

[0014] Preferably, the first stator lamination is an annular lamination.

[0015] Further, the outer side of the yoke of the first stator lamination is provided with a plurality of oil passing holes at equal intervals in the circumferential direction, and the at least two first stator laminations are stacked according to the rule of stacking multiple laminations in turn in the front and then in the back, and the oil passing holes of the stacked first stator laminations are staggered and communicated to form a plurality of first cooling oil channels communicated with the oil inlet channel of the casing.

[0016] Further, the inner ring of the first stator lamination is provided with a plurality of first stator slots in the circumferential direction, and the first stator slots are provided with first oil grooves; the first oil grooves are combined to form the first stator core slot, and the first oil groove cavity is formed in the first stator core slot, and the winding or slot insulation in the first stator core slot and the first oil groove cavity formed by stacking the first stator lamination are combined to form a plurality of first axial cooling oil channels.

[0017] Preferably, the first oil groove is located in the middle of the bottom of the first stator slot, the first oil groove occupies 1 / 2-1 / 3 of the width of the bottom, or the first oil groove is located at the fillet of the bottom of the first stator slot, or the first oil groove is located at the side of the first stator slot.

[0018] Preferably, the second stator lamination is an annular lamination.

[0019] Further, a plurality of funnel-shaped oil inlets are equidistantly arranged along the circumference of the outer circle of the second stator punching sheet, a first oil guide groove is arranged between two adjacent oil inlets; a second oil guide groove is arranged between two adjacent first oil guide grooves; a plurality of second stator grooves are arranged along the circumferential direction of the inner circle of the second stator punching sheet, an oil outlet is arranged in the second stator groove on the inner side of the first oil guide groove; a second oil groove is arranged in the second stator groove on the inner side of the second oil guide groove; the second oil grooves after being stacked form second stator core grooves which are communicated with the first stator core grooves.

[0020] Preferably, the second oil groove is arranged at a partial bottom or a partial side of the second stator groove.

[0021] Preferably, the second stator punching sheet is stacked in a structure that a plurality of punching sheets are stacked in turn with the front surface and then with the back surface and staggered by one tooth, and the flow of the oil inlet, the first oil guide groove, the second oil guide groove and the oil outlet is adjusted by adjusting the number of stacked second stator punching sheets.

[0022] Preferably, when the number of the first stator core grooves and the second stator core grooves is N, the number of the oil inlets is N / 2; the number of the oil outlets is N / 2, and the oil outlet is communicated with the second oil groove and corresponds to the position of the oil outlet.

[0023] Preferably, the number of the second oil guide grooves is N / 2, the second oil guide groove is communicated with the oil outlet, and the position of the oil outlet is staggered with the position of the oil inlet by one slot.

[0024] Preferably, the stator winding includes an in-groove winding and a stator end winding located at both ends of the in-groove winding.

[0025] The present application integrates a plurality of cooling oil channels in the interior of the stator core, combines the stator core groove and the in-groove winding to form an axial oil guide channel, guides the cooling oil into the oil guide channel in the stator core groove through the integrated oil channel in the interior of the stator core groove, and makes the cooling oil flow to the two end surfaces of the core in the oil guide channel in the stator core groove, in which process the cooling oil directly contacts the winding in the stator core groove, realizes direct cooling of the in-groove winding, and then the oil flowing out of the oil guide channel in the stator core groove sprays on the winding at the end of the core to realize direct contact cooling of the winding at the end of the core. The present application realizes direct contact cooling of the cooling oil, the in-groove winding and the end winding, and greatly improves the overall cooling effect. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 Cooling schematic diagram of the oil-cooled motor

[0027] Figure 2 Sectional view of the stator core in the present application

[0028] Figure 3 A perspective view of the stator core in the present application

[0029] Figure 4 A partial view of the first stator lamination in the present application

[0030] Figure 4-1 A partial view of the first stator lamination in the present application

[0031] Figure 4-2 A partial view of the first stator lamination in the present application

[0032] Figure 4-3 A partial view of the first stator lamination in the present application

[0033] Figure 5 A partial view of the first stator lamination in the present application

[0034] Figure 6 A partial view of the second stator lamination in the present application

[0035] Figure 7 A partial view of the second stator lamination in the present application

[0036] Figure 8 A partial view of the second stator lamination in the present application

[0037] Figure 9 A partial view of the second stator lamination in the present application

[0038] Figure 10 A partial view of the second stator lamination in the present application DETAILED DESCRIPTION

[0039] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0040] The terms used in the embodiments of the present application are merely for the purpose of describing specific embodiments and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. "Plural" generally includes at least two, but does not exclude the case of including at least one.

[0041] It should be understood that the term "and / or" as used herein merely describes an associated relationship among associated objects and can represent a plurality of relationships, for example, A and / or B can represent three cases: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " herein generally represents an "or" relationship between the front and rear associated objects.

[0042] Depending on the context, the word "if" as used herein can be interpreted to mean "when" or "while" or "in response to determining" or "in response to detecting." Similarly, the phrase "if it is determined" or "if (a stated condition or event) is detected" can be interpreted to mean "when it is determined" or "in response to determining" or "when (the stated condition or event) is detected" or "in response to detecting (the stated condition or event)".

[0043] It should also be noted that the terms "comprise", "comprising", or any other variant thereof are intended to cover a non-exclusive inclusion, such that a product or system that comprises a list of elements does not only include those elements, but can also include other elements not expressly listed or inherent to such product or system. Without more limitations, an element defined by the phrase "comprising a" does not exclude the presence of additional identical elements in the product or system comprising the element.

[0044] As shown in Figures 1 to 10 An oil-cooled motor according to the present application is shown in FIG. 1. As shown in Figures 1 to 3 The oil-cooled motor according to the present application comprises a motor housing 10, a stator core 20 fixed in the motor housing 10, a stator winding 30 mounted on the stator core 20, and a rotor 40 rotatably sleeved in the stator core 20.

[0045] The stator winding 30 in the present application comprises a stator core slot winding 301 and a stator end winding 302 located at both ends of the stator core slot winding 301.

[0046] The inner wall of the motor housing 10 is provided with a motor housing oil inlet channel 101. In the present embodiment, the motor housing oil inlet channel 101 is located on the inner wall of the right upper part of the motor housing 10, the right end surface is an inlet communicated with an oil pump 50, and the outlet is located at the middle position of the inner wall of the motor housing.

[0047] The stator core 20 in the present application comprises two groups of first stator core laminations 201 stacked together and a second stator core lamination group stacked by a plurality of second stator core laminations 202. The outer diameter of the second stator core lamination 202 is smaller than the outer diameter of the first stator core lamination 201.

[0048] The first stator lamination group in the application is arranged at both ends of the second stator lamination group, i.e. the second stator lamination group is located at the middle position of the two first stator lamination groups.

[0049] The outer side of the yoke part of the first stator lamination group is provided with a first cooling oil channel 2011 in the circumferential direction, and the inner ring of the first stator lamination group is provided with a first stator core slot 2012, and the first stator core slot 2012 is provided with a first axial cooling oil channel 2013.

[0050] The outer circle of the second stator lamination group in the application is provided with an annular oil channel 2020, and the oil inlet channel 101 of the shell is communicated with the first cooling oil channel 2011, the first axial cooling oil channel 2013 and the annular oil channel 2020.

[0051] Reference Figure 4 and Figure 5 As shown in the figure, the first stator lamination 201 is an annular sheet, and a plurality of oil passing holes 21 are arranged at the outer side of the yoke part of the first stator lamination 201 in the circumferential direction at equal intervals, and the first stator lamination 201 is stacked according to the rule of stacking multiple sheets in turn in the front face and then in the back face, and the oil passing holes 21 of the stacked first stator lamination are staggered and communicated to form a plurality of first cooling oil channels 2011 communicated with the oil inlet channel 101 of the shell.

[0052] Further, a plurality of first stator slots 212 are arranged in the circumferential direction at the inner ring of the first stator lamination 201, and a first oil groove 2121 is arranged in the first stator slot 212; the first oil groove 2121 after stacking is combined to form the first stator core slot 2013, and a first oil channel cavity is formed in the first stator core slot 2013, and the first oil channel cavity is formed by the combination of the first stator lamination 201 and the first oil groove 2121 after stacking.

[0053] The first stator lamination 201 in the embodiment can be provided with various structures, mainly changing the position of the first oil groove 2121, i.e. the first oil groove 2121 can be arranged at different positions of the first stator slot 212, i.e. different structures, and the following three schemes are listed in the embodiment for illustration:

[0054] As Figure 4 Scheme 1 in the embodiment:

[0055] The first oil groove 2121 in the application is located in the middle of the bottom of the first stator slot 212, and the first oil groove 2121 occupies 1 / 2-1 / 3 of the width of the bottom of the first stator slot 212, and the first stator lamination 201 is stacked according to the method of stacking multiple sheets in turn in the front face and then in the back face, and the bottom of the first stator slot 212 forms the first axial cooling oil channel 2011.

[0056] like Figure 4-1 Scheme 2 in this embodiment:

[0057] In this invention, the first oil groove 2121 is located at the two rounded corners of the bottom of the first stator groove 212. The first stator laminations 201 are stacked alternately by pressing multiple laminations on the front and then multiple laminations on the back. Two oil channels are formed at the two rounded corners of the bottom of the first stator groove 212. The oil outlet of the second stator lamination 202 is connected to the oil channels at the two rounded corners of the first stator groove 212. (Refer to...) Figure 5 This is a schematic diagram of the structure after the first stator lamination 201 is stacked.

[0058] like Figure 4-2 Scheme 3 in this embodiment:

[0059] In this invention, the first oil groove 2121 is disposed on both sides of the first stator groove 212. Preferably, the first oil groove 2121 is made asymmetrical. The first stator laminations 201 are stacked alternately by stacking multiple laminations on the front side and then stacking multiple laminations on the back side. When the first stator laminations 201 are stacked on both sides of the first stator groove 212, two oil passages are formed within the groove. (Refer to...) Figure 4-3 This is a magnified view of a portion of the first stator lamination 201 after it has been stacked.

[0060] like Figures 6 to 10 As shown, the second stator lamination 202 in this invention is an annular lamination.

[0061] Multiple funnel-shaped oil inlets 2022 are evenly spaced along the outer circle 2021 of the second stator lamination 202. A first oil guide groove 2024 is formed between two adjacent oil inlets 202. A second oil guide groove 2023 is formed between two adjacent first oil guide grooves 2024. Multiple second stator slots 2026 are formed along the circumferential direction on the inner ring of the second stator lamination 202. An oil outlet 2025 is formed in the second stator slot 2026 located inside the first oil guide groove 2024. A second oil groove 2027 is formed in the second stator slot 2026 located inside the second oil guide groove 2023. The stacked second oil grooves 2027 are combined to form a second stator core slot 2028 that communicates with the first stator core slot 2013.

[0062] In this invention, the second oil groove 2027 is located partially at the bottom or side of the second stator groove 2026. Preferably, the second stator laminations 202 are stacked in a structure where multiple laminations are stacked on the front side and then on the back side with a staggered tooth. The flow rates of the oil inlet 2022, the first oil guide groove 202, the second oil guide groove 2024, and the oil outlet 2025 are adjusted by adjusting the number of stacked second stator laminations 202.

[0063] In the embodiment, when the first stator core slot number 2013 and the second stator core slot number 2028 are N, the number of the oil inlet 2022 is N / 2; the number of the oil outlet 2025 is N / 2, and the oil outlet 2025 is in communication with the second oil groove 2027, and the position of the oil outlet 2025 corresponds to the position of the oil inlet 2022.

[0064] When the number of the second oil guide groove 2024 is N / 2, the second oil guide groove 2024 is in communication with the oil outlet 2025, and the position of the oil outlet 2025 is staggered with the position of the oil inlet 2022 by one slot.

[0065] Reference Figure 9 and Figure 10 In the embodiment, the second stator lamination 202 can be provided with various structures, that is, a plurality of second stator grooves 2026 are formed in the inner circle of the second stator lamination 202 in the circumferential direction, and a plurality of funnel-shaped oil inlets 2022 are formed in the outer circle 2021 of the second stator lamination 202 at equal intervals in the circumferential direction. The first oil guide groove 2024 is formed at the bottom of the second stator groove 2026, the second oil guide groove 2023 is formed at the oil inlet 2022, and reference Figure 10 is a structure schematic view of the second stator lamination 202 after superposition.

[0066] The cooling process of the application is as follows:

[0067] When the cooling oil pumped out by the oil pump 50 enters the stator core annular oil channel 202 through the integrated oil inlet channel 101 in the casing 10, the annular oil channel 202 is filled with cooling oil, and the cooling oil in the annular oil channel 202 is divided into two parts. One part of the cooling oil enters the plurality of first axial cooling oil channels 2013 of the yoke part of the stator core, and flows in the axial direction to the two end surfaces of the stator core 20. During the flow process, the cooling oil directly contacts the stator core 202 and carries away the heat of the stator core 20, and flows out from the oil channel openings of the front and rear two end surfaces, and is directly sprayed to the two end part windings 302 of the stator, thereby cooling the two end part windings 302.

[0068] The other part of the cooling oil enters the cooling oil channel in the first stator core slot 2013 and the second stator core slot 2028 through the plurality of oil inlets 2022, the second oil guide groove 2024, the first oil guide groove 202, and the oil outlet 2025 oil channel formed by the superposition of the second stator lamination group, and flows in the oil channel in the slot to the two end surfaces of the stator core 20. During the flow process, the cooling oil directly contacts the winding or slot insulation 401 in the slot, effectively cools the winding in the slot, and flows out from the oil channel openings of the end part of the stator core, and flows through the windings at the two end parts of the stator core, thereby cooling the end part windings 302 again.

[0069] The application integrates multiple cooling oil channels in the interior of the stator core, combines the stator core slot and the winding in the slot to form an axial oil branch channel, guides the cooling oil into the oil branch channel in the stator core slot through the integrated oil channel in the interior of the stator core slot, and makes the cooling oil flow to the two end surfaces of the core in the oil branch channel in the stator core slot, in which process the cooling oil directly contacts the winding in the stator core slot to directly cool the winding in the slot, and then the oil flowing out of the oil branch channel in the stator core slot sprays on the winding at the end of the core to directly contact and cool the winding at the end.

[0070] To sum up, the above only describes the preferred embodiments of the present application, and is not intended to limit the scope of the present application. Any equivalent changes and modifications made according to the content of the present application should be within the technical scope of the present application.

Claims

1. An oil-cooled motor, comprising a casing, a stator core fixed in the casing, a stator winding mounted on the stator core, and a rotor rotatably sleeved in the stator core. Its features are: An inner wall of the casing is provided with a casing oil inlet channel. The stator core comprises at least one set of first stator lamination groups and a second stator lamination group with an outer diameter smaller than that of the first stator lamination groups; the first stator lamination groups are arranged at both ends of the second stator lamination group. The outer side of the yoke of the first stator lamination group is provided with a first cooling oil channel in the circumferential direction, and the inner circle of the first stator lamination group is provided with a first stator core slot, and the first stator core slot is provided with a first axial cooling oil channel. The outer circle of the second stator lamination group is provided with an annular oil channel. The casing oil inlet channel is communicated with the first cooling oil channel, the first axial cooling oil channel and the annular oil channel. The first stator lamination is an annular sheet. The outer side of the yoke of the first stator lamination is provided with a plurality of oil passing holes at equal intervals in the circumferential direction, and the at least two first stator laminations are stacked according to the rule of stacking a plurality of laminations in turn front to front and back to back; the oil passing holes of the stacked first stator laminations are staggered and communicated to form a plurality of first cooling oil channels communicated with the casing oil inlet channel. A plurality of first stator slots are formed in the inner circle of the first stator lamination in the circumferential direction, and a first oil groove is formed in the first stator slot; the first oil groove is combined to form the first stator core slot, and a first oil channel cavity is formed in the first stator core slot; the winding or slot insulation in the first stator core slot and the first oil channel cavity formed by stacking the first stator lamination are combined to form a plurality of first axial cooling oil channels; the second stator lamination is an annular sheet. A plurality of funnel-shaped oil inlets are formed at equal intervals in the circumferential direction along the outer circle of the second stator lamination, and a first oil guide groove is formed between adjacent two oil inlets; a second oil guide groove is formed between adjacent two first oil guide grooves; a plurality of second stator slots are formed in the inner circle of the second stator lamination in the circumferential direction, an oil outlet is formed in the second stator slot inside the first oil guide groove; a second oil groove is formed in the second stator slot inside the second oil guide groove; the second oil groove is combined to form a second stator core slot communicated with the first stator core slot.

2. The oil-cooled electric machine of claim 1, wherein: The first stator lamination group is stacked by at least two first stator laminations; the second stator lamination group is stacked by at least two second stator laminations; the second stator lamination group is symmetrically arranged at the middle position of the first stator lamination group.

3. The oil-cooled electric machine of claim 2, wherein: The first oil groove is located in the middle of the slot bottom of the first stator slot, and the first oil groove occupies 1 / 2-1 / 3 of the width of the slot bottom, or the first oil groove is located at the fillet of the slot bottom of the first stator slot, or the first oil groove is located at the side of the first stator slot.

4. The oil-cooled electric machine of claim 3, wherein: The second oil groove is arranged at the local or partial side of the slot bottom of the second stator slot.

5. The oil-cooled electric machine of claim 4, wherein: The second stator lamination is stacked according to the structure of stacking a plurality of laminations in turn front to front and back to back with a plurality of laminations stacked with a tooth offset; the flow of the oil inlet, the first oil guide groove, the second oil guide groove and the oil outlet is adjusted by adjusting the number of stacked second stator laminations.

6. The oil-cooled electric machine of claim 5, wherein: When the first and second stator core slots are N, the number of oil inlet ports is N / 2; the number of oil outlet ports is N / 2, and the oil outlet ports are in communication with the second oil grooves and correspond to the positions of the oil outlet ports.

7. The oil-cooled electric machine of claim 6, wherein: The number of the second oil guide grooves is N / 2, the second oil guide grooves are in communication with the oil outlet ports, and the positions of the oil outlet ports are staggered with the positions of the oil inlet ports by one slot.

8. The oil-cooled electric machine of any one of claims 1-7, wherein: The stator winding comprises a stator core slot inner winding and a stator end portion winding located at both ends of the stator core slot inner winding.

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