Patent Description:
A motor is an electromagnetic apparatus that implements conversion or transfer of electrical energy according to a law of electromagnetic induction. A main function of the motor is to generate a driving torque and act as a power source of electric appliances or various machines. With miniaturization of a motor in a powertrain, power density of the motor is gradually increased. With an increase in the power density of the motor, improving heat dissipation efficiency and a heat dissipation capability of the motor becomes a technical issue to be urgently resolved.

At present, the motor mainly includes a housing, a stator core, a rotor, and a coil winding. Generally, structural members are disposed at two ends of the stator core, the structural members and the housing form a sealing cavity body, and the stator core, the rotor, and the coil winding are located inside the sealing cavity body. A large amount of heat is generated when the motor is running. A water cooling or oil cooling manner is usually used to dissipate heat of the motor.

However, in the oil cooling manner of the motor, effective heat dissipation cannot be implemented on the stator core and the coil winding in the motor, resulting in a poor heat dissipation effect of a stator and the coil winding. This incurs a risk that overtemperature easily occurs in the coil winding when the motor is in low-speed high-torque and high rotational speed conditions. <CIT> concerns an electric machine that includes a stator core having opposing first and second end faces, an outer surface between the end faces, and a plurality of fluid passageways defined within the stator core. <CIT> concerns an electric machine having a stator arranged in a machine housing and a rotor mounted rotatably relative to the stator about an axis of rotation, wherein the machine housing includes at least one coolant inlet port for supplying coolant to the machine housing and at least one coolant outlet port for draining coolant from the machine housing. <CIT> discloses a system and method for cooling an electric motor comprising a plurality of laminations defining a lamination stack, a coolant passage and a motor winding. Coolant is pumped into the coolant passage and forced along the entire length of the lamination stack. The coolant is then sprayed on the motor winding in order to cool the motor winding. <CIT> relates to a reluctance motor, in particular to a switched reluctance motor with a water injection type winding and a shaft-diameter-circumference multi-directional self-circulation ventilation system. <CIT> concerns an apparatus, for example, for use with a rotating electric machine, that includes a housing. The housing can include a housing main portion and a housing end portion. The housing main portion can be configured to be disposed proximal to a body portion of a stator section of an electric machine. The housing main portion can define a main fluid channel that is configured to conduct fluid therethrough. The housing end portion can receive fluid from said main fluid channel and direct fluid into contact with a winding end portion of a conductive winding of the stator section.

The invention concerns a motor as defined in claim <NUM> and a powertrain as defined in claim <NUM>. The invention thus provides a motor and a powertrain, to form double-layer oil channels at an outer surface of a stator core and a root of a coil slot of the stator core, and ensure effective cooling of the stator core and a coil winding, thereby ensuring a heat dissipation requirement of the motor in low-speed high-torque and high rotational speed conditions, and resolving a problem that overtemperature easily occurs in the coil winding when the motor is in the low-speed high-torque and high rotational speed conditions because of poor heat dissipation of the stator core and the coil winding in the existing motor.

A first aspect of embodiments of this application provides a motor, including a housing, where at least a stator is disposed in the housing, the stator includes a stator core and a coil winding, an inner surface of the stator core is provided with a plurality of coil slots disposed at intervals, and the coil winding is partially located inside the coil slots;.

The plurality of first oil channels are formed between the inner surface of the housing and the outer surface of the stator core, the second oil channels are formed at groove roots of the coil slots of the stator core, the first oil channel can cool the outer surface of the stator core, and the second oil channel can dissipate heat around the coil slot of the stator core and heat of the coil winding, to form double-layer oil channels at the outer surface of the stator core and the root of the coil slot of the stator core. The two-layer oil channels are designed to increase a contact area between cooling oil and the stator, thereby significantly improving heat dissipation capabilities of the stator and coils. In addition, one end of the plurality of first oil channels is connected to the some of the second oil channels, the other end of the plurality of first oil channels is connected to the remaining second oil channel, and the second oil channels are connected to the nozzles at the end parts of the motor. After the cooling oil is injected from the oil filling port, a flow direction of the cooling oil in the some of the second oil channels is opposite to that of the cooling oil in the remaining second oil channel, so that interleaved reverse flows are implemented, and axial temperature of the stator core and the coil winding is more even. Therefore, the motor provided in this embodiment of this application ensures effective cooling of the stator core and the coil winding, thereby ensuring a heat dissipation requirement of the motor in low-speed high-torque and high rotational speed conditions, and resolving a problem that overtemperature easily occurs in the coil winding when the motor is in the low-speed high-torque and high rotational speed conditions because of poor heat dissipation of the stator core and the coil winding in the existing motor.

In a possible implementation, the motor further includes a first end cap and a second end cap, where.

In a possible implementation, a third oil channel is formed between the first end cap and one end face of the stator core;.

In a possible implementation, the first end cap includes at least a first annular end plate, and the third oil channel is formed between the first annular end plate and one end face of the stator core; and
the second end cap includes at least a second annular end plate, and the fourth oil channel is formed between the second annular end plate and the other end face of the stator core.

In a possible implementation, the plurality of first nozzles are circumferentially disposed at intervals along the first annular end plate; and
the plurality of second nozzles are circumferentially disposed at intervals along the second annular end plate. In this way, the cooling oil sprayed out from the plurality of first nozzles can circumferentially perform even heat dissipation on a first end part of the coil winding, and the cooling oil sprayed out from the plurality of second nozzles can circumferentially perform even heat dissipation on a second end part of the coil winding.

In a possible implementation, orthographic projections of the plurality of second nozzles towards the first annular end plate and the plurality of first nozzles are circumferentially arranged alternately on the first annular end plate.

In a possible implementation, an inner edge of the first annular end plate is provided with a plurality of first separation blocks disposed at intervals, one end of the first separation block abuts on one end face of the stator core, the first separation block is provided with the first nozzle, and the first nozzle is separated from the third oil channel by using the first separation block; and
an inner edge of the second annular end plate is provided with a plurality of second separation blocks disposed at intervals, one end of the second separation block abuts on the other end face of the stator core, the second separation block is provided with the second nozzle, and the second nozzle is separated from the fourth oil channel by using the second separation block.

In a possible implementation, the first separation block is provided with a first recessed portion, and the first nozzle is located at the first recessed portion; and
the second separation block is provided with a second recessed portion, and the second nozzle is located at the second recessed portion.

In a possible implementation, the first end cap further includes an axially protruded first extension plate connected to an outer edge of the first annular end plate, and the second end cap further includes an axially protruded second extension plate connected to an outer edge of the second annular end plate;.

In a possible implementation, both the first extension plate and the second extension plate are of annular structures, and both the first oil injection chamber and the second oil injection chamber are annular chambers.

In a possible implementation, both the first extension plate and the second extension plate are arc segments, and the first extension plate and the second extension plate are located at top outer edges of the first annular end plate and the second annular end plate, respectively.

In a possible implementation, a plurality of first through grooves and a plurality of second through grooves are provided on the outer surfaces of the first extension plate and the second extension plate, respectively;.

In a possible implementation, a fifth oil channel is disposed in the housing, and the fifth oil channel is connected to all of the oil filling port, the first oil injection chamber, and the second oil injection chamber. In this case, the first oil injection chamber and the second oil injection chamber are connected to the oil filling port through the fifth oil channel in the housing. The cooling oil enters the first oil injection chamber and the second oil injection chamber through the fifth oil channel in the housing, and cools the first end part and the second end part of the coil winding. This shortens a flow path of the cooling oil when the cooling oil cools the first end part and the second end part of the coil winding, thereby achieving relatively desirable heat dissipation for the first end part and the second end part of the coil winding.

In a possible implementation, a plurality of sixth oil channels are disposed in the first annular end plate, and two ends of the plurality of sixth oil channels are connected to the first oil injection chamber and the some of the second oil channels, respectively; and
a plurality of seventh oil channels are disposed in the second annular end plate, and two ends of the plurality of seventh oil channels are connected to the second oil injection chamber and the remaining second oil channel, respectively.

In a possible implementation, a plurality of first grooves are provided on the outer surface of the first extension plate, and two ends of the first groove are connected to the sixth oil channel and the first oil injection chamber, respectively; and
a plurality of second grooves are provided on the outer surface of the second extension plate, and two ends of the second groove are connected to the seventh oil channel and the second oil injection chamber, respectively.

In a possible implementation, oil outlet ports are respectively provided on groove walls that are of the first groove and the second groove and that are close to the stator core, the oil outlet port on the first groove is connected to the sixth oil channel, and the oil outlet port on the second groove is connected to the seventh oil channel;.

In a possible implementation, a third groove is provided on the outer surface of the first extension plate, and the first oil injection chamber is enclosed by the third groove and the inner surface of the housing; and
a fourth groove is provided on the outer surface of the second extension plate, and the second oil injection chamber is enclosed by the fourth groove and the inner surface of the housing.

In a possible implementation, a plurality of oil grooves are provided on the outer surface of the stator core, the plurality of oil grooves are circumferentially disposed at intervals along the periphery of the stator core, and two ends of each oil groove extend to two end faces of the stator core; and
the first oil channel is enclosed by the oil groove and the inner surface of the housing.

In a possible implementation, groove bottoms of at least some of the oil grooves are uneven and arcuate groove bottoms.

In a possible implementation, the plurality of oil grooves are even in groove widths, the plurality of oil grooves are different in groove widths, or groove widths of some of the plurality of oil grooves are greater than a groove width of a remaining oil groove.

In a possible implementation, a plurality of first bumps disposed at intervals are provided at an outer edge of a surface that is of the first end cap and that faces the stator core, the plurality of first bumps are circumferentially disposed along the outer edge of the first end cap, and one end of the first bump abuts on one end face of the stator core;.

In a possible implementation, the nozzle is of a flat structure or the nozzle is of a circular structure.

In a possible implementation, the nozzle is an inclined nozzle that inclines towards a direction of the coil winding.

In a possible implementation, fifth grooves are provided at the slot bottoms of the at least some of the coil slots, an insulation layer is disposed in the coil slot, and the coil winding is insulated from the stator core by using the insulation layer; and the second oil channel is enclosed by the fifth groove and some of the insulation layers.

In a possible implementation, a notch width of the fifth groove is a, a slot bottom width of the coil slot is b, and a is less than b.

In a possible implementation, a groove bottom width of the fifth groove is c, and c is greater than a.

A second aspect of embodiments of this application provides a powertrain, including at least a reducer and the motor according to any one of the foregoing implementations. The motor is connected to the reducer through a rotating shaft. The motor is included, so that double-layer oil channels are formed at an outer surface of a stator core and a root of a coil slot of the stator core. In this way, a first oil channel can cool the outer surface of the stator core, and a second oil channel can dissipate heat around the coil slot of the stator core and heat of a coil winding. After cooling oil is injected from an oil filling port, a flow direction of the cooling oil in some of second oil channels is opposite to that of cooling oil in a remaining second oil channel, so that interleaved reverse flows are implemented, and axial temperature of the stator core and the coil winding is more even. This ensures effective cooling of the stator core and the coil winding, thereby ensuring a heat dissipation requirement of the motor in low-speed high-torque and high rotational speed conditions. In addition, the powertrain can be miniaturized, and a desirable heat dissipation capability of the powertrain is ensured, thereby improving performance of the powertrain.

A non-claimed third aspect of embodiments of this application provides a device, including at least a wheel, a transmission component, and the motor according to any one of the foregoing implementations. The motor is connected to the wheel through the transmission component. The motor is included, so that double-layer oil channels are formed at an outer surface of a stator core and a root of a coil slot of the stator core. In this way, a first oil channel can cool the outer surface of the stator core, and a second oil channel can dissipate heat around the coil slot of the stator core and heat of a coil winding. After cooling oil is injected from an oil filling port, a flow direction of the cooling oil in some of second oil channels is opposite to that of cooling oil in a remaining second oil channel, so that interleaved reverse flows are implemented, and axial temperature of the stator core and the coil winding is more even. This ensures effective cooling of the stator core and the coil winding, thereby ensuring a heat dissipation requirement of the motor in low-speed high-torque and high rotational speed conditions, and ensuring desirable working performance of the device in different working conditions.

Terms used in embodiments of this application are merely used to describe specific embodiments of this application, but are not intended to limit this application.

A large amount of heat is usually generated when a motor is running. To cool the motor, in some researches, an oil channel is usually provided on an outer surface of a stator core in the motor, and the stator core is cooled by using the oil channel; or an oil channel is provided in a coil winding in the motor, and the coil winding is cooled by using the oil channel in the coil winding.

Driven by markets, powertrains develop towards miniaturization. To keep same power as an original powertrain, a highest rotational speed and current density of a motor in a miniaturized powertrain need to be further increased. However, an increase in the highest rotational speed leads to an increase in a loss of a stator core, and an increase in the current density leads to a significant increase in a loss of coils. With an existing heat dissipation capability, at low-speed high-torque conditions, a coil winding is at an overtemperature risk due to the increase in the current density, while at a high speed, the increase in the loss of the stator core causes the middle of the coils (that is, a part of the coil winding located in a coil slot of the stator core) to be at an overtemperature risk. Consequently, an existing motor cooling manner greatly restricts a miniaturization design of the powertrain.

To resolve the foregoing technical problem, an embodiment of this application provides a motor. A plurality of first oil channels <NUM> are formed between an inner surface <NUM> of a housing <NUM> in the motor <NUM> and an outer surface of a stator core <NUM>, second oil channels <NUM> are formed at groove roots of coil slots <NUM> of the stator core <NUM>, the first oil channel <NUM> can cool the outer surface of the stator core <NUM>, and the second oil channel <NUM> can directly dissipate heat around the coil slot <NUM> of the stator core <NUM> and heat of a coil winding <NUM>, to form double-layer oil channels at the outer surface of the stator core <NUM> and the root of the coil slot <NUM> of the stator core <NUM>. The two-layer oil channels are designed to increase a contact area between cooling oil and a stator, thereby significantly improving heat dissipation capabilities of the stator and coils. In addition, one end of the plurality of first oil channels <NUM> is connected to some of the second oil channels <NUM>, the other end of the plurality of first oil channels <NUM> is connected to a remaining second oil channel <NUM>, and the second oil channels <NUM> are connected to nozzles at end parts of the motor <NUM>. After the cooling oil is injected from an oil filling port, a flow direction of the cooling oil in the some of the second oil channels <NUM> is opposite to that of the cooling oil in the remaining second oil channel <NUM>, so that interleaved reverse flows are implemented, and axial temperature of the stator core <NUM> and the coil winding <NUM> is more uniform. Therefore, the motor <NUM> provided in this embodiment of this application ensures effective cooling of the stator core <NUM> and the coil winding <NUM>, thereby ensuring a heat dissipation requirement of the motor <NUM> in low-speed high-torque and high rotational speed conditions, and resolving a problem that overtemperature easily occurs in the coil winding <NUM> when the motor <NUM> is in the low-speed high-torque and high rotational speed conditions because of poor heat dissipation of the stator core <NUM> and the coil winding <NUM> in the existing motor <NUM>.

This embodiment of this application provides the motor <NUM>. The motor <NUM> can be applied to an electric vehicle (EV), a pure device (Pure Electric Vehicle/Battery Electric Vehicle), a hybrid electric vehicle (HEV), a range extended electric vehicle (REEV), a plug-in hybrid electric vehicle (PHEV), a new energy vehicle, a battery management device, a motor & driver, a power converter, a reducer, and the like.

In this embodiment of this application, referring to <FIG> and <FIG>, the motor <NUM> includes the housing <NUM>, a rotor (not shown) and a stator <NUM> are disposed in the housing <NUM>, the stator <NUM> is sheathed on a periphery of the rotor, the stator <NUM> includes the stator core <NUM> and the coil winding <NUM>, and the coil winding <NUM> is wound around the stator core <NUM>.

When the coil winding <NUM> is wound around the stator core <NUM>, specifically, referring to <FIG>, a plurality of coil slots <NUM> are evenly distributed on an inner surface of the stator core <NUM> in a circumferential direction, the plurality of coil slots <NUM> are disposed at intervals, and the coil winding <NUM> is wound around the stator core <NUM> through the coil slots <NUM>.

When the coil winding <NUM> is wound in the coil slots <NUM> of the stator core <NUM>, two end parts of the coil winding <NUM> extend outwardly from two ends of the stator core <NUM> (refer to <FIG>). In other words, an axial length of the coil winding <NUM> is usually greater than that of the stator core <NUM>. In this embodiment of this application, the end parts of the coil winding <NUM> are two ends of the coil winding <NUM> that extend from the two ends of the stator core <NUM>. For example, in <FIG>, the coil winding <NUM> includes middle coils <NUM> located in the coil slot <NUM>, and a first end part <NUM> and a second end part <NUM> that extend from the coil slot <NUM>. Then, referring to <FIG>, the middle coils <NUM> of the coil winding <NUM> are located in the coil slot <NUM>.

In this embodiment of this application, to input the cooling oil into the motor <NUM> to dissipate heat of the stator core <NUM> and the coil winding <NUM>, referring to <FIG>, the oil filling port <NUM> is provided on the housing <NUM>, and the cooling oil is injected from the oil filling port <NUM> into the oil channels in the motor <NUM>. It should be noted that a structure of the oil filling port <NUM> includes but is not limited to the structure shown in <FIG>. In actual application, when the oil filling port <NUM> is provided on the housing <NUM>, the oil filling port <NUM> is flush with an outer surface of the housing <NUM>. In other words, a hole depth of the oil filling port <NUM> is consistent with a wall thickness of the housing <NUM>.

To allow the cooling oil injected from the oil filling port <NUM> to flow to the oil channels in the motor <NUM>, referring to <FIG>, the inner surface <NUM> of the housing <NUM> is provided with a connecting groove <NUM> along a circumferential direction of the housing <NUM>, and the connecting groove <NUM> is connected to the oil filling port <NUM>. In this way, the coolant injected from the oil filling port <NUM> can circumferentially flows in the housing <NUM> through the connecting groove <NUM>, and after the cooling oil is injected from the oil filling port <NUM>, the cooling oil can be diffused to each circumferential location of the outer surface of the stator core <NUM> through the connecting groove.

In this embodiment of this application, to cool the outer surface of the stator core <NUM> by using the cooling oil, referring to <FIG>, the plurality of first oil channels <NUM> are formed between the inner surface <NUM> of the housing <NUM> and the outer surface of the stator core <NUM>, and the plurality of first oil channels <NUM> are circumferentially disposed at intervals along a periphery of the stator core <NUM>. For example, the plurality of first oil channels <NUM> may be circumferentially disposed at intervals on the outer surface of the stator core <NUM>. Through the connecting groove <NUM>, the plurality of first oil channels <NUM> are connected to the oil filling port <NUM> provided on the housing <NUM>. In this way, after the cooling oil is injected from the oil filling port <NUM>, the cooling oil can be diffused to each first oil channel <NUM> through the connecting groove <NUM>. Therefore, the cooling oil in the first oil channels <NUM> can cool the outer surface of the stator core <NUM>.

To also cool the coil winding <NUM> and the inner surface of the stator core <NUM>, referring to <FIG> and <FIG>, the second oil channels <NUM> are formed at slot bottoms of the coil slots <NUM> of the stator core <NUM>. It should be noted that the plurality of coil slots <NUM> are circumferentially disposed at intervals along the inner surface of the stator core <NUM>, and the second oil channels <NUM> may be formed at the slot bottoms of all the coil slots <NUM>, or second oil channels <NUM> may be formed at slot bottoms of some of the coil slots <NUM> and no second oil channel <NUM> may be formed at slot bottoms of some other coil slots <NUM>. Therefore, the second oil channels <NUM> may be formed at slot bottoms of at least some of the coil slots <NUM>. In this embodiment of this application, to dissipate heat of the coil winding <NUM> in each coil slot <NUM>, the second oil channels <NUM> (refer to <FIG>) are formed at the slot bottoms of all the coil slots <NUM>, and the plurality of second oil channels <NUM> are circumferentially disposed at intervals along the inner surface of the stator core <NUM>. In this way, the cooling oil entering the second oil channels <NUM> can dissipate heat of the middle coils <NUM> of the coil winding <NUM> and a region that is of the stator core <NUM> and that is close to the second oil channels <NUM>.

To make the cooling oil in the first oil channel <NUM> enter the second oil channel <NUM>, the first oil channel <NUM> and the second oil channel <NUM> need to be connected to each other. In this embodiment of this application, to implement axial even heat dissipation on the coil winding <NUM> and the stator core <NUM>, one end of the plurality of first oil channels <NUM> is connected to one end of the some of the second oil channels <NUM>, and the other end of the some of the second oil channels <NUM> is connected to nozzles at one end of the motor <NUM>. For example, referring to <FIG>, the cooling oil may enter the some of the second oil channels <NUM> (for example, a second oil channel 102a) from a left end of the first oil channel <NUM>, and may be sprayed out from the nozzles (for example, a second nozzle <NUM>) at one end of the motor <NUM> after passing through the second oil channel <NUM>. The other end of the plurality of first oil channels <NUM> is connected to one end of the remaining second oil channel <NUM>, and the other end of the remaining second oil channel <NUM> is connected to nozzles at the other end of the motor <NUM>. For example, the cooling oil may enter the remaining second oil channel <NUM> (for example, a second oil channel 102b) from a right end of the first oil channel <NUM>, and may be sprayed out from the nozzles (for example, a first nozzle <NUM>) at the other end of the motor <NUM> after passing through the remaining second oil channel <NUM>.

It should be noted that, when the cooling oil is injected from the oil filling port <NUM>, the cooling oil is usually under specific pressure. Therefore, the cooling oil is sprayed out from the first nozzle <NUM> and the second nozzle <NUM> to the first end part <NUM> and the second end part <NUM> of the coil winding <NUM> with specific pressure.

In this embodiment of this application, distribution of second oil channels 102a and second oil channels 102b is shown in <FIG>, and a plurality of second oil channels 102a and a plurality of second oil channels 102b are alternately disposed at intervals along an axial direction of the stator core <NUM>. Then, referring to <FIG>, after entering the first oil channels <NUM>, the cooling oil separately flows to two ends of the first oil channels <NUM> along solid arrows and dashed arrows. <FIG> is a schematic diagram of cutting the stator along one of the second oil channels 102a at a top of the stator. Referring to <FIG>, the cooling oil enters the plurality of second oil channels 102a from one end of the plurality of first oil channels <NUM> (refer to solid arrows in <FIG>), and the cooling oil enters the plurality of second oil channels 102b from the other end of the plurality of first oil channels <NUM> (refer to dashed arrows in <FIG>). A flow direction of the cooling oil in the plurality of second oil channels 102a is opposite to that of the cooling oil in the plurality of second oil channels 102b (refer to the solid arrows and the dashed arrows in <FIG>), so that interleaved reverse flows are implemented. In this way, the cooling oil can separately flow to the two end parts of the coil winding <NUM>, thereby implementing even heat dissipation on the two end parts of the coil winding <NUM>.

When the cooling oil in the second oil channels 102a and the cooling oil in the second oil channels 102b are sprayed out from nozzles on different sides, specifically, referring to <FIG>, the cooling oil in the second oil channels 102a is sprayed out from the second nozzle <NUM> to the second end part <NUM> of the coil winding <NUM>. There may be a plurality of second nozzles <NUM>. Referring to the solid arrows on a right side in <FIG>, the cooling oil is sprayed out from the second nozzles <NUM> to the second end part <NUM> of the coil winding <NUM>. The cooling oil in the plurality of second oil channels 102b is sprayed out from the first nozzle <NUM> to the first end part <NUM> of the coil winding <NUM>. Referring to <FIG>, there are a plurality of first nozzles <NUM>. Referring to the dashed arrows on a left side in <FIG>, the cooling oil is sprayed out from the plurality of first nozzles <NUM> to the first end part <NUM> of the coil winding <NUM>.

Therefore, in this embodiment of this application, the interleaved reverse flows of the cooling oil in the plurality of second oil channels <NUM> ensure that the cooling oil sprayed out from the first nozzles <NUM> and the second nozzles <NUM> can respectively cool the first end part <NUM> and the second end part <NUM> of the coil winding <NUM>. In this way, the cooling oil in the first oil channels <NUM> implements effective heat dissipation on the outer surface of the stator core, and the cooling oil in the second oil channels <NUM> implements effective heat dissipation on an inner side of the stator core <NUM> and the middle coils <NUM> of the coil winding <NUM>. In addition, the interleaved reverse flows of the cooling oil in the second oil channels <NUM> implements heat dissipation on the two end parts of the coil winding <NUM>. Finally, not only effective heat dissipation is implemented on the stator, but also axial even heat dissipation is ensured for the stator. This avoids a risk that overtemperature occurs because of poor partial heat dissipation of the coil winding <NUM> and the stator core <NUM>.

It should be noted that in some examples, distribution of the plurality of second oil channels 102a and the plurality of second oil channels 102b includes but is not limited to the structure shown in <FIG>. For example, two or more second oil channels 102b may be distributed between two adjacent second oil channels 102a. An arrangement manner may be: a second oil channel 102a, a second oil channel 102b, a second oil channel 102b, a second oil channel 102a, a second oil channel 102b, and a second oil channel 102b.

<FIG> is a schematic diagram when a second oil channel 102b is cut along the top of the stator. Flow directions of the cooling oil in the first oil channel <NUM> and the second oil channel <NUM> are indicated by solid arrows and dashed arrows in <FIG>. The cooling oil is sprayed out from the first nozzle <NUM> along the dashed arrows, and the cooling oil is sprayed out from the second nozzle <NUM> along the solid arrows.

It should be noted that, when one end of the plurality of first oil channels <NUM> is connected to the plurality of second oil channels 102a, one end of each first oil channel <NUM> may be connected to all the second oil channels 102a, or one end of the plurality of first oil channels <NUM> may be connected to all the second oil channels 102a, respectively. For example, cooling oil flowing from one end of the plurality of first oil channels <NUM> converges and then enters each second oil channel 102a. To prevent the cooling oil at one end of the plurality of first oil channels <NUM> from entering the second oil channels 102b, two ends of the second oil channels 102a and two ends of the second oil channels 102b are blocked. This ensures that one end of the plurality of first oil channels <NUM> is connected to the plurality of second oil channels 102a and is not connected to the plurality of second oil channels 102b.

To implement the connection between the first oil channels <NUM> and the second oil channels <NUM> and the interleaved reverse flows of the cooling oil in the plurality of second oil channels <NUM>, referring to <FIG>, a first end cap <NUM> and a second end cap <NUM> are further included. The first end cap <NUM> and the second end cap <NUM> are respectively located at the two ends of the stator core <NUM>. The first end cap <NUM> is provided with a plurality of first nozzles <NUM> disposed at intervals, and the second end cap <NUM> is provided with a plurality of second nozzles <NUM> disposed at intervals. One end of the plurality of first oil channels <NUM> is connected to one end of the some of the second oil channels <NUM> (for example, a second oil channel 102a) through the first end cap <NUM>, and the other end of the some of the second oil channels <NUM> is connected to the plurality of second nozzles <NUM>. The other end of the plurality of first oil channels <NUM> is connected to one end of the remaining second oil channel <NUM> (for example, a second oil channel 102b) through the second end cap <NUM>, and the other end of the remaining second oil channel <NUM> is connected to the plurality of first nozzles <NUM>.

Specifically, referring to <FIG>, a third oil channel <NUM> is formed between the first end cap <NUM> and one end face of the stator core <NUM>, and a fourth oil channel <NUM> is formed between the second end cap <NUM> and the other end face of the stator core <NUM>. It should be noted that the third oil channel <NUM> is distributed throughout a circumferential direction between the first end cap <NUM> and the end face of the stator core <NUM>, the fourth oil channel <NUM> is correspondingly distributed throughout a circumferential direction between the second end cap <NUM> and the other end face of the stator core <NUM>, and the third oil channel <NUM> and the fourth oil channel <NUM> are annular oil channels.

One end of the plurality of first oil channels <NUM> is connected to one end of the some of the second oil channels <NUM> through the third oil channel <NUM>, and the other end of the plurality of first oil channels <NUM> is connected to one end of the remaining second oil channel <NUM> through the fourth oil channel <NUM>. Specifically, one end of the plurality of first oil channels <NUM> is connected to the third oil channel <NUM>, that is, the cooling oil flows from one end of the plurality of first oil channels <NUM> to the third oil channel <NUM> for convergence, and then mixed cooling oil enters the some of the second oil channels 102a. Correspondingly, the other end of the plurality of first oil channels <NUM> is connected to the fourth oil channel <NUM>, that is, the cooling oil flows from the other end of the plurality of first oil channels <NUM> to the fourth oil channel <NUM> for convergence, and then mixed cooling oil enters the some of the second oil channels 102b.

In this embodiment of this application, by using the third oil channel <NUM> and the fourth oil channel <NUM>, a flow mixing function of the cooling oil is implemented at the third oil channel <NUM> and the fourth oil channel <NUM>, and flows of the cooling oil are circumferentially distributed more evenly, so that unevenness of circumferential temperature of the stator is reduced, and even heat dissipation is circumferentially implemented on the stator.

It should be noted that the first nozzle <NUM> on the first end cap <NUM> is spaced from (that is, not connected to) the third oil channel <NUM> and is connected to the fourth oil channel <NUM>, and the second nozzle <NUM> on the second end cap <NUM> is spaced from (that is, not connected to) the fourth oil channel <NUM> and is connected to the third oil channel <NUM>. This ensures that the cooling oil entering the third oil channel <NUM> is not directly sprayed out from the first nozzle <NUM>, and correspondingly the cooling oil entering the fourth oil channel <NUM> is not directly sprayed out from the second nozzle <NUM>.

A heat dissipation effect of the motor <NUM> provided in this embodiment is simulated. In this embodiment, two motors <NUM> with different structures are selected as reference for simulation. Specifically, <FIG> is a partial schematic diagram of a heat transfer path when an oil channel is disposed in a coil winding <NUM> in a motor <NUM>. Referring to <FIG>, an oil channel 102c is disposed only in the coil winding <NUM> (specifically, in the middle coils <NUM> of the coil winding <NUM>), heat of the outer surface of the stator core <NUM> and heat that is of the stator core <NUM> and that is close to the coil slot <NUM> are diffused to the oil channel 102c along solid arrow directions for heat dissipation, and heat of the coil winding <NUM> is diffused to the oil channel 102c along two dashed arrow directions.

<FIG> is a partial schematic diagram of a heat transfer path when an oil channel is disposed at a groove root of a coil slot <NUM> in a motor <NUM>. As shown in <FIG>, an oil channel 102c is formed at the groove root of the coil slot <NUM>, heat of the outer surface of the stator core <NUM> and heat that is of the stator core <NUM> and that is close to the coil slot <NUM> are diffused to the oil channel 102c along solid arrow directions for heat dissipation, and heat of the coil winding <NUM> is diffused to the oil channel 102c along a dashed arrow direction. The heat transfer path for the outer surface of the stator core <NUM> in <FIG> is shortened compared with <FIG>.

<FIG> is a partial schematic diagram of a heat transfer path during heat dissipation of a motor <NUM> according to an embodiment of this application. As shown in <FIG>, the first oil channel <NUM> is formed between the outer surface of the stator core <NUM> and the housing <NUM>, and the second oil channel <NUM> is formed at the groove root of the coil slot <NUM>. In this case, a part of heat in the middle of the stator core <NUM> and heat that is of the stator core <NUM> and that is close to the coil slot <NUM> are transferred to the second oil channel <NUM> along solid arrows for heat dissipation, heat of the coil winding <NUM> is transferred to the second oil channel <NUM> along a dashed arrow direction for heat dissipation, and heat of the outer surface of the stator core <NUM> and a part of heat in the middle of the stator core <NUM> are transferred to the first oil channel <NUM> along other solid arrows for heat dissipation.

Compared with <FIG> and <FIG>, in the motor <NUM> provided in this embodiment, two-layer oil channels, that is, the first oil channel <NUM> and the second oil channel <NUM>, are disposed to shorten the heat transfer path, and the two-layer oil channels increase a contact area between the stator core <NUM> and the oil channels. Through simulation, it is found that the motor <NUM> provided in this embodiment of this application reduces maximum temperature of the stator by approximately <NUM> compared with the case in which the oil channel is disposed only at the groove root of the coil slot <NUM>, and reduces the maximum temperature of the stator by approximately <NUM> compared with the case in which the oil channel is disposed in the coil winding <NUM>. Therefore, the motor <NUM> provided in this embodiment improves a cooling effect on the stator and implements effective heat dissipation on the stator core <NUM> and the coil winding <NUM>.

Therefore, for the motor <NUM> provided in this embodiment, the plurality of first oil channels <NUM> are formed between the inner surface <NUM> of the housing <NUM> in the motor <NUM> and the outer surface of the stator core <NUM>, the second oil channels <NUM> are formed at the groove roots of the coil slots <NUM> of the stator core <NUM>, the first oil channel <NUM> can cool the outer surface of the stator core <NUM>, and the second oil channel <NUM> can directly dissipate heat around the coil slot <NUM> of the stator core <NUM> and heat of the coil winding <NUM>, to form the double-layer oil channels at the outer surface of the stator core <NUM> and the root of the coil slot <NUM> of the stator core <NUM>. The two-layer oil channels are designed to increase the contact area between the cooling oil and the stator, thereby significantly improving the heat dissipation capabilities of the stator and the coils. In addition, one end of the plurality of first oil channels <NUM> is connected to the some of the second oil channels <NUM>, the other end of the plurality of first oil channels <NUM> is connected to the remaining second oil channel <NUM>, and the second oil channels <NUM> are connected to the nozzles at the end parts of the motor <NUM>. After the cooling oil is injected from the oil filling port <NUM>, the flow direction of the cooling oil in the some of the second oil channels <NUM> is opposite to that of the cooling oil in the remaining second oil channel <NUM>, so that interleaved reverse flows are implemented, and axial temperature of the stator core <NUM> and the coil winding <NUM> is more uniform. Therefore, the motor <NUM> provided in this embodiment of this application ensures effective cooling of the stator core <NUM> and the coil winding <NUM>, thereby ensuring the heat dissipation requirement of the motor <NUM> in the low-speed high-torque and high rotational speed conditions, and resolving the problem that overtemperature easily occurs in the coil winding <NUM> when the motor <NUM> is in the low-speed high-torque and high rotational speed conditions because of poor heat dissipation of the stator core <NUM> and the coil winding <NUM> in the existing motor <NUM>.

In this embodiment, when the plurality of first oil channels <NUM> are formed between the outer surface of the stator core <NUM> and the inner surface of the housing <NUM>, a possible implementation is as follows: As shown in <FIG>, a plurality of oil grooves <NUM> are provided on the outer surface of the stator core <NUM>, the plurality of oil grooves <NUM> are circumferentially disposed at intervals along the periphery of the stator core <NUM>, and two ends of each oil groove <NUM> extend to two end faces of the stator core <NUM>; and the first oil channel <NUM> is enclosed by the oil groove <NUM> and the inner surface <NUM> of the housing <NUM>.

Alternatively, in another possible implementation, a plurality of oil grooves <NUM> are provided on the inner surface <NUM> of the housing <NUM>, and the plurality of oil grooves <NUM> are circumferentially disposed at intervals along an inner circumference of the housing <NUM>; and the first oil channel <NUM> is enclosed by the oil groove <NUM> and the outer surface of the stator core <NUM>.

Alternatively, in another possible implementation, a plurality of oil grooves <NUM> are provided on the outer surface of the stator core <NUM>, the plurality of oil grooves <NUM> are circumferentially disposed at intervals along the periphery of the stator core <NUM>, and two ends of each oil groove <NUM> extend to two end faces of the stator core <NUM>; and a plurality of oil grooves <NUM> are provided on the inner surface <NUM> of the housing <NUM>, and the plurality of oil grooves <NUM> are circumferentially disposed at intervals along an inner circumference of the housing <NUM>. The first oil channel <NUM> is enclosed by the oil groove <NUM> on the inner surface of the housing <NUM> and the oil groove <NUM> on the outer surface of the stator core <NUM>.

In this embodiment of this application, the following specifically provides a description by using an example in which the first oil channel <NUM> is enclosed by the oil groove <NUM> on the outer surface of the stator core <NUM> and the inner surface of the housing <NUM>.

In this embodiment of this application, when the oil grooves <NUM> are provided on the outer surface of the stator core <NUM>, groove widths or cross-sectional shapes of the plurality of oil grooves <NUM> may be the same; or as shown in <FIG>, groove widths or cross-sectional shapes of the plurality of oil grooves <NUM> are different.

In this embodiment of this application, groove bottoms of at least some of the oil grooves <NUM> are uneven and arcuate groove bottoms. For example, referring to <FIG>, in the plurality of oil grooves <NUM>, a groove bottom of an oil groove 22c is uneven and arcuate. In this way, when the cooling oil passes through the first oil channel <NUM>, a contact area between the stator core <NUM> and the cooling oil is increased, thereby implementing effective heat dissipation on the outer surface of the stator core <NUM>. Alternatively, the plurality of oil grooves <NUM> are even in groove widths, the plurality of oil grooves <NUM> are different in groove widths, or referring to <FIG>, groove widths of some of the plurality of oil grooves <NUM> are greater than a groove width of a remaining oil groove <NUM>. For example, a groove width of an oil groove 22b is less than a groove width of an oil groove 22a. In this case, a quantity of the oil grooves 22b to be provided can be increased with a same area. This increases the contact area between the cooling oil and the stator core <NUM>, thereby desirably cooling the outer surface of the stator core <NUM>.

In this embodiment of this application, when the first oil channel <NUM> is formed at the slot bottoms (that is, groove roots) of the at least some of the coil slots <NUM>, a possible implementation is as follows: Fifth grooves <NUM> are provided at the slot bottoms of the at least some of the coil slots <NUM>. For example, referring to <FIG>, a fifth groove <NUM> is provided at a slot bottom of each coil slot <NUM>. Referring to <FIG>, an insulation layer <NUM> is disposed in the coil slot <NUM>. For example, the insulation layer <NUM> is disposed on a groove wall of the coil slot <NUM>, and the coil winding <NUM> is insulated from the stator core <NUM> by using the insulation layer <NUM>. To be specific, the insulation layer <NUM> is used to prevent the coil winding <NUM> from being in electrical contact with the groove wall of the coil slot <NUM> of the stator core <NUM>. The second oil channel <NUM> is enclosed by the fifth groove <NUM> and some of the insulation layers <NUM>. For example, a part that is of the insulation layer <NUM> and that is located at a notch of the fifth groove <NUM> seals the notch of the fifth groove <NUM>, so that the second oil channel <NUM> is enclosed by the insulation layer <NUM> at the notch of the fifth groove <NUM> and a groove wall of the fifth groove <NUM>.

Certainly, in some other examples, an opening may alternatively be disposed at a slot bottom that is of the stator core <NUM> and that is close to the coil slot <NUM>, to form the second oil channel <NUM>. In this embodiment, the second oil channel <NUM> is specifically formed in a manner shown in <FIG>.

In this embodiment, to facilitate arrangement of the insulation layer <NUM> at the notch of the fifth groove <NUM>, referring to <FIG>, a notch width of the fifth groove <NUM> is a, a slot bottom width of the coil slot <NUM> is b, and a is less than b. In this way, a step <NUM> is formed at a junction between the fifth groove <NUM> and the coil slot <NUM>, and the insulation layer <NUM> may abut on the step to seal the notch of the fifth groove <NUM>. It is convenient to dispose the insulation layer <NUM> at the notch of the fifth groove <NUM> because a is less than b.

In this embodiment of this application, when a is less than b, contact areas between the cooling oil and the coil winding <NUM> and between the cooling oil and the stator core <NUM> are relatively small. To implement desirable heat dissipation on the coil winding <NUM> and the stator core <NUM>, in this embodiment, a groove bottom width of the fifth groove <NUM> is c, and c is greater than a. In this way, the formed first oil channel <NUM> can accommodate more cooling oil, thereby desirably cooling the coil winding <NUM> and the stator core <NUM>.

In this embodiment of this application, referring to <FIG>, an outer cross-sectional contour of the fifth groove <NUM> is T-shaped. Certainly, in some other examples, the outer cross-sectional contour of the fifth groove <NUM> may alternatively be umbrella-shaped or fan-shaped.

It should be noted that in this embodiment of this application, the groove bottom width c of the fifth groove <NUM> may be greater than or equal to the slot bottom width b of the coil slot <NUM>.

In this embodiment of this application, <FIG> is a schematic diagram of a cross-section in <FIG> along an E-E direction. Referring to <FIG> and <FIG>, a first oil channel 101a is formed between the oil groove 22a (refer to <FIG>) and the inner surface of the housing <NUM>, a first oil channel 101b is formed between the oil groove 22b (refer to <FIG>) and the inner surface of the housing <NUM>, and a first oil channel 101c is formed between the oil groove 22c (refer to <FIG>) and the inner surface of the housing <NUM>.

In this embodiment of this application, <FIG> is an enlarged schematic diagram of a dashed-line box portion in <FIG>. Referring to <FIG>, the cooling oil injected from the oil filling port <NUM> enters the connecting groove <NUM>, and the cooling oil enters each first oil channel <NUM> through the connecting groove <NUM>.

In the following five embodiments, a manner is detailed in which one end of the plurality of first oil channels <NUM> is connected to the some of the second oil channels 102a through the first end cap <NUM> and the other end of the plurality of first oil channels <NUM> is connected to the remaining second oil channel 102b through the second end cap <NUM>.

In this embodiment of this application, referring to <FIG>, the first end cap <NUM> includes at least a first annular end plate <NUM>, and the third oil channel <NUM> is formed between the first annular end plate <NUM> and one end face of the stator core <NUM> (refer to <FIG> below). Referring to <FIG>, the second end cap <NUM> includes at least a second annular end plate <NUM>, and the fourth oil channel <NUM> is formed between the second annular end plate <NUM> and the other end face of the stator core <NUM> (refer to <FIG> below).

Referring to <FIG>, the plurality of first nozzles <NUM> are circumferentially disposed at intervals along the first annular end plate <NUM>. Referring to <FIG>, the plurality of second nozzles <NUM> are circumferentially disposed at intervals along the second annular end plate <NUM>. In this way, the cooling oil sprayed out from the plurality of first nozzles <NUM> can circumferentially perform even heat dissipation on the first end part <NUM> of the coil winding <NUM>, and the cooling oil sprayed out from the plurality of second nozzles <NUM> can circumferentially perform even heat dissipation on the second end part <NUM> of the coil winding <NUM>.

Referring to <FIG>, an inner edge <NUM> (refer to <FIG>) of the first annular end plate <NUM> is provided with a plurality of first separation blocks <NUM> disposed at intervals, and one end of the first separation block <NUM> abuts on one end face of the stator core <NUM>. Referring to <FIG>, the first separation block <NUM> is provided with the first nozzle <NUM>, and the first nozzle <NUM> is separated from the third oil channel <NUM> by using the first separation block <NUM>. Referring to <FIG>, after the first end cap <NUM> is mounted, the first separation block <NUM> seals one end that is of the plurality of second oil channels 102b and that is towards the first end cap <NUM>, so that the third oil channel <NUM> is not connected to the plurality of second oil channels 102b but is connected to the plurality of second oil channels 102a (refer to solid arrows in <FIG>). The first nozzle <NUM> is provided on the first separation block <NUM>, to ensure that the second oil channel 102b is connected to the first nozzle <NUM>. Therefore, in this embodiment, disposing the first separation block <NUM> implements separation between the third oil channels <NUM> and some second oil channels 102b and the connection between the some second oil channels 102b and the first nozzles <NUM>.

Referring to <FIG>, the first separation block <NUM> is provided with a first recessed portion <NUM>, and the first nozzle <NUM> is located at the first recessed portion <NUM>. Referring to <FIG>, an opening area of the first recessed portion <NUM> is greater than that of the first nozzle <NUM>. In this way, the other end of the some of the second oil channels 102b is connected to the first recessed portion <NUM>, so that the some of the second oil channels 102b can be connected to the first nozzles <NUM>, thereby reducing a difficulty in mounting the first nozzles <NUM> and the second oil channels 102b in a one-to-one correspondence manner. In addition, after the first recessed portion <NUM> is connected to the second oil channel 102b, a location of the first nozzle <NUM> is not limited to a location of one end of the second oil channel 102b. For example, when the first nozzle <NUM> is close to the first end part <NUM> of the coil winding <NUM>, the cooling oil sprayed out from the first nozzle <NUM> usually comes into contact with a region that is of the first end part <NUM> and that is close to the stator core <NUM> and cools this region, while poor heat dissipation occurs in a region that is of the first end part <NUM> and that is far away from the stator core <NUM>, because this region usually does not come into contact with the cooling oil. Therefore, in this embodiment, when the first nozzle <NUM> is provided on the first recessed portion <NUM>, the first nozzle <NUM> may be vertically far away from the first end part <NUM>, so that the cooling oil sprayed out from the first nozzle <NUM> can also cool an outer end of the first end part <NUM>.

Correspondingly, referring to <FIG>, an inner edge <NUM> of the second annular end plate <NUM> is provided with a plurality of second separation blocks <NUM> disposed at intervals, one end of the second separation block <NUM> abuts on the other end face of the stator core <NUM>, the second separation block <NUM> is provided with the second nozzle <NUM>, and the second nozzle <NUM> is separated from the fourth oil channel <NUM> by using the second separation block <NUM>. In this way, the second separation block <NUM> separates the fourth oil channel <NUM> from some of the second oil channels 102a and connects the some of the second oil channels 102a and the second nozzles <NUM>.

Referring to <FIG>, the second separation block <NUM> is provided with a second recessed portion <NUM>, and the second nozzle <NUM> is located at the second recessed portion <NUM>. For a function of the second recessed portion <NUM>, reference may be made to the function of the first recessed portion <NUM> described above.

Referring to <FIG>, a plurality of first bumps <NUM> disposed at intervals are provided at an outer edge <NUM> of a surface that is of the first end cap <NUM> and that faces the stator core <NUM>, a first spacing <NUM> is provided between two adjacent first bumps <NUM>, and the plurality of first bumps <NUM> are circumferentially disposed along the outer edge of the first end cap <NUM>. Second bumps <NUM> are provided at an outer edge <NUM> of a surface that is of the second end cap <NUM> and that faces the stator core <NUM>, a second spacing <NUM> is provided between two adjacent second bumps <NUM>, and the plurality of second bumps <NUM> are circumferentially disposed along the outer edge of the second end cap <NUM>.

<FIG> is an enlarged schematic diagram of a dashed-line box portion in <FIG>. As shown in <FIG>, one end of the first bump <NUM> abuts on one end face of the stator core <NUM>, and one end of the second bump <NUM> abuts on the other end face of the stator core <NUM>. Referring to <FIG>, each first bump <NUM> is staggered from one end of the first oil channel <NUM> in a circumferential direction, so that the cooling oil in the first oil channel <NUM> can enter the third oil channel <NUM> through the first spacing <NUM> (refer to <FIG>). Correspondingly, each second bump <NUM> is staggered from the other end of the first oil channel <NUM> in a circumferential direction, so that the cooling oil enters the fourth oil channel <NUM> through the second spacing <NUM> (refer to <FIG>).

In this embodiment, referring to <FIG>, orthographic projections of the plurality of second nozzles <NUM> towards the first annular end plate <NUM> and the plurality of first nozzles <NUM> are circumferentially arranged alternately on the first annular end plate <NUM>. This can implement axial even heat dissipation on the two end parts of the coil winding <NUM>.

In this embodiment of this application, as shown in <FIG>, the first nozzles <NUM> and the second nozzles <NUM> are flat nozzles. For example, the first nozzles <NUM> and the second nozzles <NUM> may be rectangular or strip-shaped. In this way, coverage regions of the cooling oil sprayed out from the first nozzles <NUM> and the second nozzles <NUM> are wider, so that a contact area between the two end parts of the coil winding <NUM> and the cooling oil is larger and a heat dissipation effect is better.

<FIG> and <FIG> are schematic diagrams of cross-sections of the motor <NUM> at two different locations according to this embodiment. Referring to <FIG>, the first separation block <NUM> and the second separation block <NUM> respectively abut on the two end faces of the stator core <NUM> to isolate the oil channels. Referring to <FIG>, after the cooling oil in the first oil channel <NUM> flows along a solid arrow and enters the third oil channel <NUM>, the cooling oil cannot enter each second oil channel 102b due to blocking of each first separation block <NUM>, but enters each second oil channel 102a through the third oil channel <NUM> and is finally sprayed out from the second nozzle <NUM>. In contrast, after the cooling oil in the first oil channel <NUM> flows along a dashed arrow and enters the fourth oil channel <NUM>, the cooling oil enters each second oil channel 102b through the fourth oil channel <NUM>, but cannot enter each second oil channel 102a due to blocking of each first separation block <NUM>, and is finally sprayed out from the first nozzle <NUM>.

A difference between this embodiment of this application and Embodiment <NUM> lies in that, in this embodiment of this application, referring to <FIG> and <FIG>, the first nozzle <NUM> is a circular nozzle; and referring to <FIG>, the second nozzle <NUM> is a circular nozzle. Referring to <FIG>, the plurality of first nozzles <NUM> are circumferentially disposed evenly at intervals. Referring to <FIG>, the first nozzle <NUM> is provided on the first recessed portion <NUM> of the first separation block <NUM>, and the first nozzle <NUM> is close to the outer edge of the first end cap <NUM>.

In this embodiment of this application, when the first nozzle <NUM> and the second nozzle <NUM> are configured as circular nozzles, the circular nozzles can cause the cooling oil to be sprayed out to the two end parts of the coil winding <NUM> at a higher speed under same oil pressure.

In this embodiment of this application, the nozzle is an inclined nozzle that inclines towards a direction of the coil winding <NUM>. For example, referring to <FIG> and <FIG>, the second nozzle <NUM> is inclined towards a direction of the second end part <NUM> of the coil winding <NUM>, so that the cooling oil can be centrally sprayed out to the second end part <NUM> along an inclined solid arrow in <FIG>. Referring to <FIG>, the first nozzle <NUM> is inclined towards a direction of the first end part <NUM> of the coil winding <NUM>, so that the cooling oil can be centrally sprayed out to the first end part <NUM> along an inclined dashed arrow in <FIG>.

It should be noted that when the first nozzle <NUM> and the second nozzle <NUM> are inclined nozzles, the shapes of the first nozzle <NUM> and the second nozzle <NUM> include but are not limited to circular shapes. To be specific, when the first nozzle <NUM> and the second nozzle <NUM> are of flat structures, the first nozzle <NUM> and the second nozzle <NUM> may be configured to be inclined.

The first nozzle <NUM> and the second nozzle <NUM> are inclined towards the first end part <NUM> and the second end part <NUM>, respectively, so that the cooling oil is centrally sprayed out to the two end parts of the coil winding <NUM>, thereby implementing desirable heat dissipation on the two end parts of the coil winding <NUM>.

A difference between this embodiment of this application and the foregoing two embodiments lies in that, in this embodiment of this application, the first nozzle <NUM> and the second nozzle <NUM> may be disposed face to face with the first end part <NUM> and the second end part <NUM>. <FIG> is a three-dimensional diagram of a stator after the housing <NUM> in <FIG> is removed. Referring to <FIG>, the first end cap <NUM> further includes an axially protruded first extension plate <NUM> connected to an outer edge of the first annular end plate <NUM>. To be specific, one end of the first extension plate <NUM> is connected to the outer edge of the first annular end plate <NUM>, and the other end of the first extension plate <NUM> protrudes outwards along the axial direction of the stator core <NUM>. The second end cap <NUM> further includes an axially protruded second extension plate <NUM> connected to an outer edge of the second annular end plate <NUM>. To be specific, one end of the second extension plate <NUM> is connected to the outer edge of the second annular end plate <NUM>, and the other end of the second extension plate <NUM> protrudes outwards along the axial direction of the stator core <NUM>. The first extension plate <NUM> is disposed face to face with the first end part <NUM>, and the second extension plate <NUM> is disposed face to face with the second end part <NUM>.

Referring to <FIG> and <FIG>, a first oil injection chamber <NUM> is formed between an outer surface of the first extension plate <NUM> and the housing <NUM>, and the first extension plate <NUM> is provided with the plurality of first nozzles <NUM> connected to the first oil injection chamber <NUM>. In other words, in this embodiment of this application, the first nozzles <NUM> are provided on the first extension plate <NUM>. A second oil injection chamber <NUM> is formed between an outer surface of the second extension plate <NUM> and the housing <NUM>, and the second extension plate <NUM> is provided with the plurality of second nozzles <NUM> connected to the second oil injection chamber <NUM>. In other words, the second nozzles <NUM> are provided on the second extension plate <NUM>.

To implement a connection between the second nozzle <NUM> and the second oil channel 102a and a connection between the first nozzle <NUM> and the second oil channel 102b, in this embodiment of this application, both the first oil injection chamber <NUM> and the second oil injection chamber <NUM> are connected to the oil filling port <NUM>. In this way, the cooling oil flows from one end of the plurality of first oil channels <NUM> to the third oil channel <NUM> along a solid arrow, enters some of the second oil channels 102b after being mixed in the third oil channel <NUM>, enters the second oil injection chamber <NUM> after passing through the second oil channels 102b, and is finally sprayed out from the second nozzle <NUM> to the second end part <NUM>. The cooling oil flows from the other end of the plurality of first oil channels <NUM> to the fourth oil channel <NUM> along a dashed arrow, enters some of the second oil channels 102a after being mixed in the fourth oil channel <NUM>, enters the first oil injection chamber <NUM> after passing through the second oil channels 102a, and is finally sprayed out from the first nozzle <NUM> on the first extension plate <NUM>.

When the first oil injection chamber <NUM> and the second oil injection chamber <NUM> are connected to the oil filling port <NUM>, an implementation is as follows: Referring to <FIG> and <FIG>, a plurality of sixth oil channels <NUM> are disposed in the first annular end plate <NUM>, the plurality of sixth oil channels <NUM> are disposed at intervals in the first annular end plate <NUM>, and two ends of the plurality of sixth oil channels <NUM> are connected to the first oil injection chamber <NUM> and the some of the second oil channels 102a, respectively. In this way, one end of the sixth oil channel <NUM> is connected to the oil filling port <NUM> through the second oil channel 102a, the fourth oil channel <NUM>, and the first oil channel <NUM>. The cooling oil enters the first oil injection chamber <NUM> through the sixth oil channel <NUM> along dashed arrows in <FIG> and is sprayed out from the first nozzle <NUM> to the first end part <NUM>.

Referring to <FIG> and <FIG>, a plurality of seventh oil channels <NUM> are disposed in the second annular end plate <NUM>, and two ends of the plurality of seventh oil channels <NUM> are connected to the second oil injection chamber <NUM> and the remaining second oil channel 102b, respectively. In this way, one end of the seventh oil channel <NUM> is connected to the oil filling port <NUM> through the second oil channel 102b, the third oil channel <NUM>, and the first oil channel <NUM>. The cooling oil enters the seventh oil channel <NUM> along a solid arrow in <FIG>, enters the second oil injection chamber <NUM> through the seventh oil channel <NUM>, and is sprayed out from the second nozzle <NUM> to the second end part <NUM>.

In this embodiment of this application, when the first oil injection chamber <NUM> is formed between the first extension plate <NUM> and an inner wall of the housing <NUM>, a possible implementation is as follows: Referring to <FIG>, a third groove <NUM> is provided on the outer surface of the first extension plate <NUM>, and the first oil injection chamber <NUM> is enclosed by the third groove <NUM> and the inner surface <NUM> of the housing <NUM>. A fourth groove <NUM> is provided on the outer surface of the second extension plate <NUM>, and the second oil injection chamber <NUM> is enclosed by the fourth groove <NUM> and the inner surface <NUM> of the housing <NUM>.

In this embodiment of this application, referring to <FIG> and <FIG>, both the first extension plate <NUM> and the second extension plate <NUM> are of annular structures, and therefore both the first oil injection chamber <NUM> and the second oil injection chamber <NUM> are annular chambers.

In this embodiment of this application, to implement better heat dissipation in circumferential directions of the first end part <NUM> and the second end part <NUM>, referring to <FIG>, a plurality of first grooves <NUM> are provided on the outer surface of the first extension plate <NUM>, and two ends of the first groove <NUM> are connected to the sixth oil channel <NUM> and the first oil injection chamber <NUM>, respectively (refer to <FIG>). Referring to <FIG>, the cooling oil passes through the sixth oil channel <NUM> and then enters the annular first oil injection chamber <NUM> under the guidance of the first groove <NUM> to be mixed. Under the guidance action of the first groove <NUM>, it is ensured that the cooling oil remains at relatively high oil pressure after being mixed in the second oil injection chamber <NUM>, so that the cooling oil is sprayed out from the first nozzle <NUM> to the first end part <NUM> at a relatively high speed.

Referring to <FIG>, a plurality of second grooves <NUM> are provided on the outer surface of the second extension plate <NUM>, and two ends of the second groove <NUM> are connected to the seventh oil channel <NUM> and the second oil injection chamber <NUM>, respectively (refer to <FIG>). In this way, the cooling oil passes through the seventh oil channel <NUM> and then enters the annular second oil injection chamber <NUM> under the guidance of the second groove <NUM> to be mixed. Under the guidance action of the second groove <NUM>, it is ensured that the cooling oil remains at relatively high oil pressure after being mixed in the first oil injection chamber <NUM>, so that the cooling oil is sprayed out from the second nozzle <NUM> to the second end part <NUM> at a relatively high speed.

Certainly, in some examples, the sixth oil channel <NUM> may be directly connected to the first oil injection chamber <NUM>, that is, no first groove <NUM> is provided on the first extension plate <NUM>. Correspondingly, the seventh oil channel <NUM> may also be directly connected to the second oil injection chamber <NUM>, that is, no second groove <NUM> is provided on the second extension plate <NUM>.

Referring to <FIG>, first oil outlet ports <NUM> are respectively provided on groove walls (for example, groove bottoms) that are of the first grooves <NUM> and that are close to the stator core <NUM>, and the first oil outlet port <NUM> is connected to the sixth oil channel <NUM> (refer to <FIG>).

Referring to <FIG>, a surface that is of the first annular end plate <NUM> and that faces the stator core <NUM> is provided with a plurality of first separation blocks <NUM> disposed at intervals, and a first oil inlet port <NUM> (refer to <FIG>) connected to the sixth oil channel <NUM> is provided on the first separation block <NUM>. The plurality of sixth oil channels <NUM> are connected to the some of the second oil channels 102b through the first oil inlet port <NUM>.

Referring to <FIG>, second oil outlet ports <NUM> are respectively provided on groove walls that are of the second grooves <NUM> and that are close to the stator core <NUM>, and the second oil outlet port <NUM> is connected to the seventh oil channel <NUM> (refer to <FIG>). A surface that is of the second annular end plate <NUM> and that faces the stator core <NUM> is provided with a plurality of second separation blocks <NUM> disposed at intervals, and a second oil inlet port <NUM> (refer to <FIG>) connected to the seventh oil channel <NUM> is provided on the second separation block <NUM>. The plurality of seventh oil channels <NUM> are connected to the remaining second oil channel 102b through the second oil inlet port <NUM>.

For a manner of disposing the first separation block <NUM> and the second separation block <NUM>, reference may be made to the foregoing embodiments. Details are not described in this embodiment of this application again.

A difference between this embodiment of this application and the foregoing embodiments lies in that, in this embodiment, a nozzle is provided on both the first annular end plate <NUM> and the first extension plate <NUM> in the first end cap <NUM>, and a nozzle is provided on both the second annular end plate <NUM> and the second extension plate <NUM> in the second end cap <NUM>. Referring to <FIG>, <FIG>, and <FIG>, the first annular end plate <NUM> is provided with a first nozzle <NUM>, and the first extension plate <NUM> is provided with a third nozzle 411a. Referring to <FIG>, the second annular end plate <NUM> is provided with a second nozzle <NUM>, and the second extension plate <NUM> is provided with a fourth nozzle 421a. As shown in <FIG> and <FIG>, the cooling oil enters some of the second oil channels 102a along dashed arrows, passes through the first recessed portion <NUM>, and is horizontally sprayed out from the first nozzle <NUM> on the first annular end plate <NUM>. The cooling oil enters the first oil injection chamber <NUM> along a solid arrow and is sprayed out from the third nozzle 411a on the first extension plate <NUM> towards the first end part <NUM>. Referring to <FIG>, the cooling oil enters the second oil injection chamber <NUM> along dashed arrows and is sprayed out from the fourth nozzle 421a on the second extension plate towards the second end part <NUM>; and the cooling oil enters the second recessed portion <NUM> along a solid arrow and is horizontally sprayed out from the second nozzle <NUM>.

Therefore, in this embodiment of this application, the first annular end plate <NUM> is provided with the first nozzle <NUM>, and the first extension plate <NUM> is provided with the third nozzle 411a, so that the cooling oil is sprayed out to the first end part <NUM> in two different directions, and a better cooling effect is achieved on the first end part <NUM>. The second annular end plate <NUM> is provided with the second nozzle <NUM>, and the second extension plate <NUM> is provided with the fourth nozzle 421a, so that the cooling oil is sprayed out to the second end part <NUM> in two different directions, and a better cooling effect is achieved on the second end part <NUM>.

In this embodiment of this application, when the first oil injection chamber <NUM> and the second oil injection chamber <NUM> are connected to the oil filling port <NUM>, another possible implementation is as follows: Referring to <FIG> and <FIG>, a plurality of first through grooves 4032a are provided on the outer surface of the first extension plate <NUM>, that is, two ends of the first through grooves 4032a are open; and the two ends of the plurality of first through grooves 4032a are connected to the first oil injection chamber <NUM> and one end of the plurality of first oil channels <NUM>, respectively (refer to <FIG>). In this way, the cooling oil enters the first oil injection chamber <NUM> through the first through groove 4032a along a solid arrow in <FIG>.

Referring to <FIG>, for a manner of disposing the first recessed portion <NUM>, the first separation block <NUM>, and the first bump <NUM>, reference may be made to descriptions in the foregoing embodiments.

Referring to <FIG>, a plurality of second through grooves 4042a are provided on the outer surface of the second extension plate <NUM>, that is, two ends of the second through grooves 4042a are open. Referring to <FIG> and <FIG>, the two ends of the plurality of second through grooves 4042a are connected to the second oil injection chamber <NUM> and the other end of the plurality of first oil channels <NUM>, respectively. In this way, the cooling oil enters the second oil injection chamber <NUM> through the second through groove 4042a along dashed arrows in <FIG>.

Therefore, in this embodiment of this application, referring to <FIG>, the two ends of the plurality of first oil channels <NUM> are respectively connected to the third oil channel <NUM> and the fourth oil channel <NUM>, and the two ends of the plurality of first oil channels <NUM> are also respectively connected to the first through groove 4032a and the second through groove 4042a. In this case, a part of the cooling oil in the plurality of first oil channels <NUM> enters the first oil injection chamber <NUM> and the second oil injection chamber <NUM> respectively through the first through groove 4032a and the second through groove 4042a, and is sprayed out from the third nozzles 411a and the fourth nozzle 421a. The cooling oil sprayed out from the third nozzle 411a and the fourth nozzle 421a does not absorb heat through the plurality of second oil channels <NUM>, and therefore temperature of the cooling oil sprayed out from the third nozzle 411a and the fourth nozzle 421a is lower than that of the cooling oil sprayed out from the first nozzle <NUM> and the second nozzle <NUM>. In this way, the cooling oil sprayed out from the third nozzle 411a and the fourth nozzle 421a can achieve a better cooling effect on the first end part <NUM> and the second end part <NUM>.

In this embodiment of this application, <FIG> shows a structure of a stator after the housing <NUM> in <FIG> is removed, and <FIG> shows a structure of the first end cap <NUM>. Referring to <FIG>, <FIG>, and <FIG>, both the first extension plate <NUM> and the second extension plate <NUM> are arc segments, that is, the first extension plate <NUM> and the second extension plate <NUM> are of non-circular structures. The first extension plate <NUM> and the second extension plate <NUM> are located at top outer edges of the first annular end plate <NUM> and the second annular end plate <NUM>, respectively. Referring to <FIG> and <FIG>, one segment, namely, the first extension plate <NUM>, is disposed along the outer edge of the first annular end plate <NUM>, and the first extension plate <NUM> may be located over the first end part <NUM>. Correspondingly, one segment, namely, the second extension plate <NUM>, is disposed along the outer edge of the second annular end plate <NUM>, and the second extension plate <NUM> may be located over the second end part <NUM>.

The first oil injection chamber <NUM> formed between the third groove <NUM> provided on the first extension plate <NUM> and the housing <NUM> is a non-circular chamber, and the second oil injection chamber <NUM> formed between the fourth groove <NUM> provided on the second extension plate <NUM> and the inner surface of the housing <NUM> is also a non-circular chamber. The plurality of first nozzles <NUM> and the plurality of second nozzles <NUM> are respectively disposed on the first annular end plate <NUM> and the second annular end plate <NUM>. For a configuration manner thereof, reference may be made to the foregoing embodiments. Details are not described in this embodiment of this application again.

Referring to <FIG>, the third groove <NUM> is provided on the first extension plate <NUM>, and a plurality of separators 4031a are disposed at intervals in the third groove <NUM>. Referring to <FIG>, the fourth groove <NUM> is provided on the second extension plate <NUM>, and a plurality of separators 4041a are disposed at intervals in the fourth groove <NUM>. The separators 4031a and the separators 4041a respectively divide inner parts of the third groove <NUM> and the fourth groove <NUM> into a plurality of grooves. In this way, the cooling oil entering the first oil injection chamber <NUM> and the second oil injection chamber <NUM> can enter all the grooves in the first oil injection chamber <NUM> and the second oil injection chamber <NUM> because of separation by the separators 4031a and the separators 4041a.

Referring to <FIG>, a plurality of rows of third nozzles 411a are provided on the first extension plate <NUM>, and a plurality of rows of fourth nozzles 421a are provided on the second extension plate <NUM>. The plurality of rows of third nozzles 411a may be connected to each of the grooves obtained through separation in the first oil injection chamber <NUM>, and the plurality of rows of fourth nozzles 421a may be connected to each of the grooves obtained through separation in the second oil injection chamber <NUM>, so that the cooling oil can be sprayed out from the third nozzles 411a and the fourth nozzles 421a at different locations to the first end part <NUM> and the second end part <NUM>. After being sprayed out to tops of the first end part <NUM> and the second end part <NUM>, the cooling oil flows down under the action of gravity (refer to solid arrows above the first end part <NUM> and dashed arrows above the second end part <NUM> of the coil winding <NUM> in <FIG>), to perform heat dissipation on the other portions of the first end part <NUM> and the second end part <NUM>. Therefore, in this embodiment of this application, the cooling oil sprayed out from the third nozzles 411a and the fourth nozzles 421a cools the first end part <NUM> and the second end part <NUM> of the coil winding <NUM> in a spray cooling manner.

In this embodiment of this application, when the first oil injection chamber <NUM> and the second oil injection chamber <NUM> are connected to the oil filling port <NUM>, a third possible implementation is as follows: Referring to <FIG>, a fifth oil channel <NUM> is disposed in the housing <NUM>, and the fifth oil channel <NUM> is connected to all of the oil filling port <NUM>, the first oil injection chamber <NUM>, and the second oil injection chamber <NUM>. In other words, the first oil injection chamber <NUM> and the second oil injection chamber <NUM> are connected to the oil filling port <NUM> through the fifth oil channel <NUM> in the housing <NUM>. As shown in <FIG>, after the cooling oil is injected from the oil filling port <NUM>, a part of the cooling oil enters the fifth oil channel <NUM>, and the other part of the cooling oil enters the plurality of first oil channels <NUM>. As shown in <FIG>, a part of the cooling oil enters the first oil injection chamber <NUM> through the fifth oil channel <NUM> along solid arrows, and is sprayed out from the third nozzle 411a to the first end part <NUM>. In addition, the other part of the cooling oil enters the third oil channel <NUM>, which is connected to some of the second oil channels 102a, through the first oil channel <NUM> along solid arrows, and finally is sprayed from the second nozzle <NUM> to the second end part <NUM> (refer to <FIG>). The cooling oil flows at the second end part <NUM> to a bottom end of the second end part <NUM> along arrows in <FIG> under the action of gravity.

Referring to <FIG>, a part of the cooling oil enters the second oil injection chamber <NUM> through the fifth oil channel <NUM> along dashed arrows, and is sprayed out from the fourth nozzle 421a to the second end part <NUM>. In addition, the other part of the cooling oil passes through the second oil channel 102a along a solid arrow, and is sprayed out from the second nozzle <NUM> to the second end part <NUM>. It should be noted that the cooling oil may be sprayed out from the first nozzles <NUM> connected to some of the second oil channels 102b to the first end part <NUM> (refer to <FIG>).

It should be noted that, in this embodiment of this application, the first oil injection chamber <NUM> and the second oil injection chamber <NUM> may alternatively not be disposed. For example, the first end cap <NUM> includes only the first annular end plate <NUM>, the second end cap <NUM> includes only the second annular end plate <NUM>, and the first extension plate <NUM> and the second extension plate <NUM> are not disposed. In this case, openings at two ends of the fifth oil channel <NUM> respectively face the first end part <NUM> and the second end part <NUM> of the coil winding <NUM>, and the oil is sprayed out to the first end part <NUM> and the second end part <NUM> of the coil winding <NUM> through the two openings of the fifth oil channel <NUM>. The coolant flows down at the tops of the first end part <NUM> and the second end part <NUM> of the coil winding <NUM> under the action of gravity, and cools the other portions of the first end part <NUM> and the second end part <NUM> of the coil winding <NUM> in a spray cooling manner.

An embodiment of this application further provides a powertrain. The powertrain can be applied to an electric vehicle (EV), a pure electric vehicle (PEV/BEV), a hybrid electric vehicle (HEV), a range extended electric vehicle (REEV), a plug-in hybrid electric vehicle (PHEV), a new energy vehicle, and the like, or can be applied to devices such as a battery management device, a motor & driver, and a power converter.

Referring to <FIG>, the powertrain includes at least a reducer and the motor <NUM> according to any one of the foregoing embodiments. The motor <NUM> is connected to the reducer (not shown) through a rotating shaft. Specifically, an output shaft of the motor <NUM> is connected to the reducer, or the reducer may be integrated with the motor <NUM> into a powertrain <NUM>.

In the powertrain provided in this embodiment of this application, the motor <NUM> is included, so that double-layer oil channels are formed at an outer surface of a stator core <NUM> and a root of a coil slot <NUM> of the stator core <NUM>. In this way, a first oil channel <NUM> can cool the outer surface of the stator core <NUM>, and a second oil channel <NUM> can dissipate heat around the coil slot <NUM> of the stator core <NUM> and heat of a coil winding <NUM>. After cooling oil is injected from an oil filling port <NUM>, a flow direction of the cooling oil in some of second oil channels <NUM> is opposite to that of cooling oil in a remaining second oil channel <NUM>, so that interleaved reverse flows are implemented, and axial temperature of the stator core <NUM> and the coil winding <NUM> is more even. This ensures effective cooling of the stator core <NUM> and the coil winding <NUM>, thereby ensuring a heat dissipation requirement of the motor <NUM> in low-speed high-torque and high rotational speed conditions. In addition, the powertrain can be miniaturized, and a desirable heat dissipation capability and heat dissipation effect of the powertrain is ensured, thereby improving performance of the powertrain.

Non-claimed embodiments of this application further provides a device. The device may be an electric vehicle (EV), a pure electric vehicle (PEV/BEV), a hybrid electric vehicle (HEV), a range extended electric vehicle (REEV), a plug-in hybrid electric vehicle (PHEV), a new energy vehicle, or the like.

The device includes at least a wheel, a transmission component, and the motor <NUM> according to any one of the foregoing embodiments, where the motor <NUM> is connected to the wheel through the transmission component. Specifically, a rotating shaft of the motor <NUM> rotates to output power, and the transmission component transfers the power to the wheel to rotate the wheel. An output shaft of the motor <NUM> may be connected to a reducer, and the reducer may be connected to the transmission component.

In the device provided in this embodiment of this application, the motor <NUM> is included, so that double-layer oil channels are formed at an outer surface of a stator core <NUM> and a root of a coil slot <NUM> of the stator core <NUM>. In this way, a first oil channel <NUM> can cool the outer surface of the stator core <NUM>, and a second oil channel <NUM> can dissipate heat around the coil slot <NUM> of the stator core <NUM> and heat of a coil winding <NUM>. After cooling oil is injected from an oil filling port <NUM>, a flow direction of the cooling oil in some of second oil channels <NUM> is opposite to that of cooling oil in a remaining second oil channel <NUM>, so that interleaved reverse flows are implemented, and axial temperature of the stator core <NUM> and the coil winding <NUM> is more even. This ensures effective cooling of the stator core <NUM> and the coil winding <NUM>, thereby ensuring a heat dissipation requirement of the motor <NUM> in low-speed high-torque and high rotational speed conditions, ensuring a desirable heat dissipation effect and heat dissipation capability of the device in different working conditions, and improving working performance of the device.

In the descriptions of embodiments of this application, it should be noted that, unless otherwise clearly specified and limited, terms "mount", "connect", and "link" should be understood in a broad sense. For example, the terms may mean a fixed connection, an indirect connection through an intermediary, an internal connection between two elements, or an interaction relationship between two elements. Persons of ordinary skill in the art can understand specific meanings of the terms in embodiments of this application based on specific cases.

Claim 1:
A motor (<NUM>), comprising a housing (<NUM>), wherein at least a stator (<NUM>) is disposed in the housing (<NUM>), the stator (<NUM>) comprises a stator core (<NUM>) and a coil winding (<NUM>), an inner surface of the stator core (<NUM>) is provided with a plurality of coil slots (<NUM>) disposed at intervals, and the coil winding (<NUM>) is partially located inside the coil slots (<NUM>); and
a plurality of first oil channels (<NUM>) are formed between an inner surface of the housing (<NUM>) and an outer surface of the stator core (<NUM>), wherein the plurality of first oil channels (<NUM>) are circumferentially disposed at intervals along a periphery of the stator core (<NUM>), and the plurality of first oil channels (<NUM>) are all connected to an oil filling port (<NUM>) provided on the housing (<NUM>); characterized in that
second oil channels (<NUM>) are formed at slot bottoms of at least some of the coil slots (<NUM>); and
one end of the plurality of first oil channels (<NUM>) is connected to one end of some of the second oil channels (<NUM>), the other end of the some of the second oil channels (<NUM>) is connected to nozzles (<NUM>) at one end of the motor (<NUM>), the other end of the plurality of first oil channels (<NUM>) is connected to one end of a remaining second oil channel (<NUM>), and the other end of the remaining second oil channel (<NUM>) is connected to nozzles (<NUM>) at the other end of the motor (<NUM>).