KR20220096306A - Structure for projecting cooling oil - Google Patents

Abstract

The present invention relates to a cooling oil spray structure. More specifically, the present invention relates to a cooling oil spray structure that enables cooling oil sprayed to a motor by a cooling pipe to more effectively penetrate into coils of a motor. The cooling oil spray structure according to some embodiments of the present invention comprises: a motor including a stator core and a coil wound around the stator core and formed obliquely from the stator core with respect to the axial direction of the stator core; a first cooling pipe disposed at one side of the motor at a predetermined distance from the coil and including a first spray hole configured to spray oil to the coil; and a second cooling pipe disposed on the other side of the motor at a predetermined distance from the coil and including a second spray hole configured to spray oil to the coil. At the side of the first spray hole, the coil is configured to spray oil to a portion extending obliquely outward from the stator core in a direction away from the first spray hole. At the side of the second spray hole, the coil is configured to spray oil to a portion extending obliquely toward the stator core in a direction away from the second spray hole. The size of the second spray hole is larger than the size of the first spray hole.

Description

Cooling oil spraying structure {STRUCTURE FOR PROJECTING COOLING OIL}

The present invention relates to a cooling oil injection structure, and more particularly, to a cooling oil injection structure that allows cooling oil injected to a motor by a cooling pipe to more effectively penetrate into a coil of a motor.

Eco-friendly vehicles are hybrid electric vehicles (HEV), plug-in hybrid electric vehicles (PHEVs), battery electric vehicles (BEVs), fuel cell vehicles to which a high-capacity, high-voltage battery that can be charged with electricity is applied. (Fuel Cell Electric Vehicle, FCEV), etc.

In these environment vehicles, a motor powered by a high-voltage battery plays a key role in driving the vehicle. The motor has an efficiency of about 90% due to losses due to heat, wind, sound, etc., and the heat accounting for about 25% of the loss causes the motor to exceed the allowable temperature. The allowable temperature is the upper limit of the temperature at which the motor can operate stably. If the temperature of the motor exceeds the allowable temperature, the coil formed in the stator of the motor is damaged due to overheating or the permanent magnet included in the rotor is demagnetized. phenomenon may occur. Accordingly, a cooling system is provided in the motor so that the motor operates within an allowable temperature, and performance and high efficiency of the cooling performance of the driving motor for miniaturization and high output of the motor are also essential.

Motor cooling methods include water cooling, air cooling, and oil cooling based on the cooling fluid, and can be divided into direct cooling and indirect cooling according to the contact method. Recently, as the importance of motor cooling performance increases according to the demand for higher performance of the motor, the oil direct cooling method with high cooling efficiency is mainly used.

In the direct cooling method, depending on the injection method, there are a rotor shaft scattering type using motor rotation, a pressure feeding type using an electric oil pump, and a submersion type using oil submersion. In recent years, due to the demand for higher cooling performance, the combination of stator cooling using an electric oil pump, rotor cooling through shaft scattering, and oil submersion is increasing.

Recently, in order to increase the efficiency of the cooling system, optimization design of the injection angle, position, size, number, etc. of the cooling pipe configured to inject oil under pressure, motor and housing shape design for cooling optimization, improvement of the cooling injection structure or cooling aid Various studies on motor cooling systems, including the development of structures, are being actively conducted.

Registered Patent Publication No. 10-2153232 (Registration Date: 2020.09.01)

The present invention has been devised to solve the above problems,

An object of the present invention is to provide a cooling oil injection structure for a motor that can improve cooling performance and cooling efficiency.

The object of the present invention is not limited to the object mentioned above, and other objects not mentioned are clearly understood by those of ordinary skill in the art to which the present invention belongs from the description below (hereinafter 'person of ordinary skill') it could be

In order to achieve the object of the present invention as described above and perform the characteristic functions of the present invention to be described later, the features of the present invention are as follows.

A cooling oil spraying structure according to some embodiments of the present invention includes: a motor including a stator core and a coil wound around the stator core and formed obliquely from the stator core with respect to an axial direction of the stator core; a first cooling pipe disposed on one side of the motor to be spaced apart from the coil by a predetermined distance and including a first injection hole configured to inject oil into the coil; and a second cooling pipe disposed on the other side of the motor spaced apart from the coil by a predetermined distance and including a second injection hole configured to inject oil into the coil, wherein at the first injection hole side, the coil configured to spray oil to a portion obliquely extending outwardly from the stator core in a direction away from the first injection hole, and at the side of the second injection hole, the coil is inclined toward the stator core in a direction away from the second injection hole It is configured to inject oil into the extending portion, and the size of the second injection hole is larger than the size of the first injection hole.

A cooling oil spraying structure according to some embodiments of the present invention includes: a motor including a stator core and a coil wound around the stator core; A first front hole arranged to be spaced apart from the coil by a certain distance on one side of the motor and configured to spray oil to a first front portion of the coil and a first front hole configured to spray oil to a first rear portion of the coil 1 A first cooling pipe including a rear hole; and a second front hole arranged to be spaced apart from the coil by a certain distance on the other side of the motor and configured to spray oil to a second front portion of the coil and a second rear portion of the coil configured to spray oil a second cooling pipe including a second rear hole, wherein the first front portion is a portion in which the coil obliquely protrudes outward with respect to the stator core and extends in a direction away from the first cooling pipe; 2 The front portion is a portion in which the coil obliquely protrudes outward with respect to the stator core and extends toward the second cooling pipe, and the first rear portion is a portion in which the coil obliquely protrudes outward with respect to the stator core to form the second cooling pipe. 1 is a portion extending toward the cooling pipe, and the second rear portion is a portion in which the coil protrudes obliquely outward with respect to the stator core and extends in a direction away from the second cooling pipe, and the size of the second front hole is The size of the first front hole is larger than the size of the second rear hole is configured to be smaller than the size of the second rear hole.

According to the present invention, there is provided a cooling oil injection structure having excellent cooling performance and cooling efficiency.

Effects of the present invention are not limited to those described above, and other effects not mentioned will be clearly recognized by those skilled in the art from the following description.

1 shows a configuration diagram of a motor cooling system of a vehicle,
2 is a view showing a hairpin motor according to an embodiment of the present invention as viewed from above;
3 is a view showing a hairpin motor according to an embodiment of the present invention as viewed from the front;
Figure 4 shows the front left side of Figure 2,
Figure 5 shows the front right side of Figure 2,
Fig. 6a shows the front left side of Fig. 2;
Fig. 6b shows a modification as the front right side of Fig. 2;

Specific structural or functional descriptions presented in the embodiments of the present invention are only exemplified for the purpose of explaining the embodiments according to the concept of the present invention, and the embodiments according to the concept of the present invention may be implemented in various forms. In addition, it should not be construed as being limited to the embodiments described herein, and it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention.

Meanwhile, in the present invention, terms such as first and/or second may be used to describe various components, but the components are not limited to the terms. The above terms are used only for the purpose of distinguishing one component from other components, for example, within the scope not departing from the scope of the rights according to the concept of the present invention, the first component may be named as the second component, Similarly, the second component may also be referred to as a first component.

When a component is referred to as being “connected” or “connected” to another component, it should be understood that it may be directly connected or connected to the other component, but other components may exist in between. something to do. On the other hand, when it is said that a certain element is "directly connected" or "directly contacted" with another element, it should be understood that no other element is present in the middle. Other expressions for describing the relationship between elements, that is, expressions such as "between" and "immediately between" or "adjacent to" and "directly adjacent to", should be interpreted similarly.

Like reference numerals refer to like elements throughout. Meanwhile, the terminology used herein is for the purpose of describing the embodiments and is not intended to limit the present invention. In this specification, the singular form also includes the plural form unless otherwise specified in the phrase. As used herein, “comprises” and/or “comprising” means that the stated component, step, operation and/or element is the presence of one or more other components, steps, operations and/or elements. or addition is not excluded.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of a motor cooling system of an environment vehicle is shown. The motor cooling system works in cooperation with the vehicle's coolant system 500 . In the vehicle cooling water system 500, the cooling water from the vehicle cooling system 510 including an electric water pump and a radiator cools the inverter 520, and passes through the heat exchanger 620 to the vehicle cooling system ( 510).

In the cooling oil system 600 , the oil circulation is started while the electric oil pump 610 pressurizes the oil by applying pressure to the oil. The oil cools the motor 630 as it is sprayed from the cooling pipe 640 of the motor 630 after heat exchange with the cooling water of the cooling water system 500 having a relatively low temperature in the heat exchanger 620 to lower the temperature.

The oil after cooling of the motor 630 flows to the reducer 650 and cools the reducer 650 through gear churning. After cooling the motor 630 and the reducer 650 , the oil is recirculated while returning to the electric oil pump 610 after removing impurities through the oil filter 660 . On the other hand, the motor cooling system includes a temperature sensor 670 for measuring the temperature of the oil passing through the oil filter 660, the temperature of the oil passing through the heat exchanger 620, and the temperature of the motor 630. The temperature is configured to be sensed.

According to the present invention, it is possible to more efficiently cool the motor through the oil injection structure in which the optimum amount of oil is injected from the cooling pipe 640 according to the coil shape of the motor 630 .

The oil injection structure according to the present invention minimizes the amount of oil injected from the cooling pipe to the coil of the motor is not utilized for cooling due to the shape of the coil and is discarded, and can maximize the effective amount of oil used for cooling the motor.

Hereinafter, an oil injection structure for a motor according to the present invention will be described in more detail with reference to FIGS. 2 to 6B .

The motor 630 includes a stator 100 and a rotor (not shown). The stator 100 includes a stator core 120 and a coil 140 , and the coil 140 is wound on the stator core 120 and coupled to the motor housing. Permanent magnets are mounted along the circumference of the rotor, and are disposed inside the stator 100 . That is, the motor 630 may be a permanent magnet synchronous motor (PMSM).

According to the present invention, the motor 630 may be, in particular, a hairpin motor. The motor may be classified according to the winding method of the coil. Among the types of motors according to the winding method of the coil, in particular, in the hairpin motor, as shown in FIG. 2 , a coil frame is formed at both ends of the stator core 120 . arranged at an oblique angle. At each end of the stator core 120 , a coil 140 protrudes to the outside of the stator core 120 . According to the embodiment of the present invention, when viewed from the front or rear of the motor 630 , the front side coil protruding from the front of the stator core 120 and the rear side coil protruding from the rear of the stator core 120 are generally It includes regions that are obliquely inclined in the same direction. For example, when the front side coil protrudes from the stator core 100 obliquely in a clockwise direction with respect to the axial direction of the stator core 120 when viewed from the rear of the motor 630 , the rear side coil rotates clockwise is introduced into the stator core 100 at an angle.

According to an embodiment of the present invention, the coil 140 of the motor 630 obliquely protrudes from the stator core 120 in the axial direction of the stator core 120 . As such, the obliquely protruding coil is bent at least once in at least one of a radial direction, a circumferential direction, and a direction between the radial and circumferential directions of the stator core 120 . The coil bent in this way is introduced into the stator core 120 at an angle with respect to the axial direction of the stator core 120 .

Oil is supplied to the coil 140 by the cooling pipe 200 , and the cooling pipe 200 provides the oil pressurized by the electric oil pump 610 to the motor 630 . More specifically, a plurality of injection holes are formed in the cooling pipe 200 , and oil is injected toward the coil 140 through the injection holes.

At this time, because of the shape of the oblique coil 140 , the oil sprayed from the cooling pipe 200 hits the coil and bounces out of the coil 140 without permeating into the inside, a so-called oil dumping phenomenon occurs.

According to the oil dumping phenomenon, the injected oil hits the coil 140 and flies to the outside of the coil 140 or the motor housing side, so the oil flow rate actually used for cooling the motor 630 is reduced compared to the supplied oil flow rate, As a result, cooling efficiency is reduced. This problem occurs not only when the flow rate is large (eg 10 liters per minute (LPM)) but also when the flow rate is small (eg 4 to 6 LPM), so a solution to the oil dump phenomenon is needed.

Accordingly, in the present invention, the size of the injection hole of the cooling pipe 200 facing each other is adjusted according to the shape of the coil 140 . Considering the shape of the coil 140, the amount of oil that permeates into the coil 140 can be increased by reducing the diameter of the hole in which the oil is expected to be dumped to the outside and increasing the diameter of the hole in the cooling pipe 200 facing it. .

The cooling pipe 200 may take various shapes such as a straight line, annular shape, or a complex shape, and a plurality of cooling pipes 200 such as 0 to 3 may be provided. Since oil can be uniformly supplied to the left and right sides of the motor 630 , two cooling pipes 200 are typically used.

In the present invention, a pair of cooling pipes 200 disposed on the left and right sides of the motor 630 will be described as an example. The cooling pipe 200 may be disposed above the motor 630 .

According to an embodiment of the present invention, the first cooling pipe 220 and the second cooling pipe 240 are disposed in the motor 630 to face each other with respect to the motor 630 .

The first cooling pipe 220 includes a plurality of injection holes, and includes a first front hole 222 formed in front of the motor 630 and a first rear hole 224 formed in the rear of the motor 630 . may include

The second cooling pipe 240 also includes a plurality of injection holes, and includes a second front hole 242 formed in front of the motor 630 and a second rear hole 244 formed in the rear of the motor 630 . may include

According to an embodiment of the present invention, the first front hole 222 and the second front hole 242 are symmetrical with respect to the motor 630 . That is, the injection angle of the first front hole 222 and the injection angle of the second front hole 242 are substantially the same.

Also, the first rear hole 224 and the second rear hole 244 may be symmetrical to each other with respect to the motor 630 . That is, the injection angle of the first rear hole 224 and the injection angle of the second rear hole 244 are provided to be substantially the same.

However, there is a case where the first cooling pipe 220 and the second cooling pipe 240 are not completely identical to each other, and the first front hole 222 and the second front hole 242 and the first rear hole ( 224) and the second rear hole 244 may not be completely symmetrical with respect to each other, so according to the present invention, it may be configured to differentiate the size of the corresponding injection hole when an angular condition to be described later is satisfied.

4 and 5 , the oil injected by the first front hole 222 in the front side coil 142 region comes into contact with the coil 142 and then the outside of the front side coil 142 or the stator core 120 ) moving away from it. Alternatively, when viewed from the side of the first front hole 222 , the oil injected from the first front hole 222 protrudes obliquely outward with respect to the stator core 120 in a direction away from the first cooling pipe 220 . The portion of the coil 142 that extends is sprayed. Accordingly, oil is bounced out from the first front hole 222 obliquely in a clockwise direction with respect to the line toward the front coil 142 where the oil comes into contact (dashed line in FIG. 4 ).

Conversely, the oil injected by the second front hole 242 in the front side coil 142 region moves in a direction closer to the inner side of the front side coil 142 or the stator core 120 after contacting the coil 142 . do. Alternatively, when viewed from the second front hole 242 side, the oil injected from the second front hole 242 is introduced obliquely toward the stator core 120 and extends in a direction away from the second cooling pipe 240 . It is sprayed into the area of the coil 142 . In other words, from the second front hole 242, oil enters the coil 142 at an angle in a clockwise direction with respect to the line toward the coil 142 on the front side where the oil comes into contact (dotted line in FIG. 5).

Accordingly, in such a case, it can be predicted that the oil dumping from the first front hole 222 of the first cooling pipe 220 will be remarkable. Meanwhile, in the present specification, the coil 140 protruding forward of the motor 630 is referred to as a front side coil 142 , and the coil 140 protruding backward of the motor 630 is referred to as a rear side coil 144 . refers to

According to the present invention, the diameter of the first front hole 222 is configured to be smaller than the diameter of the second front hole 242 . Since the amount of oil injected through the second front hole 242 is increased, it is possible to provide higher cooling performance and cooling efficiency in the same LPM situation.

Equation 1 below may be satisfied under the same situation as the front side coil 142 .

(Equation 1)

Here, d _f2 is the size of the second front hole 242 and d _f1 is the size of the first front hole 222 . k is a size change coefficient and may vary according to environmental conditions, preferably, may be 1 to 1.5, and more preferably may be 1.2. The environmental conditions may include whether machining dimensions are possible and a cooling environment.

As described above, when viewed from the rear of the stator core 120 , the front side coil 142 is angled counterclockwise with respect to the axial direction of the stator core 120 in a direction away from the stator core 120 . When extending, the rear coil 144 extends toward the stator core 120 while having an angle counterclockwise with respect to the axial direction of the stator core 120 . Accordingly, the rear side coil 144 is in the opposite situation to the front side coil 142 . The oil injected from the second rear hole 244 of the second cooling pipe 240 is bounced outward, and the oil injected from the first rear hole 224 of the first cooling pipe 220 is the coil 144 . go to the side Therefore, in this case, as shown in Equation 2, the size of the first rear hole 224 is formed to be larger than the size of the second rear hole 244 .

(Equation 2)

Here, d _r1 is the size of the first rear hole 224 and d _r2 is the size of the second rear hole 244 .

In addition, the amount of oil injected from the cooling pipe 200 and The injection pressure may remain the same. That is, as in Equation 3, as the size of the first front hole 222 in the first cooling pipe 220 is decreased, the size of the first rear hole 224 increases and the size of the second front hole 242 also increases. Since the size of the second rear hole 244 is reduced as much as is increased, it is possible to maintain the same flow rate and pressure.

(Equation 3)

Therefore, according to the present invention, it is possible to provide more improved cooling performance and efficiency in the same LPM situation as compared to the existing structure.

As described above, the cooling pipe 200 may not be perfectly symmetrical with respect to the motor 630 , the location of the injection hole formed in each cooling pipe 200 may not be perfectly symmetrical, and the range of the upper portion of the coil 140 may be There is some ambiguity. Therefore, according to the present invention, when the preset angle condition is satisfied, it is determined that the opposite injection holes cool the same position. When it is determined that the opposite injection holes cool the same position, the size of the holes is differentiated.

)라고 한다. 제2 각도(

)는 제2 냉각 파이프(240)의 중심과 제2 전방홀(242)을 연결하는 직선이 전방 측 코일(142)에 닿는 위치(P2)와 모터(630)의 중심을 연결하는 선과 수직방향 축(A)이 이루는 각도이다. 제1 각도(

)와 제2 각도(

)가 미리 설정된 각도 값을 만족하는 경우에만 크기변경계수(k)에 따라 제1 전방홀(222) 및 제2 전방홀(242)의 크기를 보정한다. 비제한적인 예로서, 미리 설정된 각도 값인 제1 각도(

)와 제2 각도(

)는, 각각, 18°일 수 있고, 그 때의 k 값은 1.2이다. Referring to FIG. 3 , a straight line connecting the center of the first cooling pipe 220 and the first front hole 222 connects the center of the motor 630 to the position P1 where the straight line contacts the front coil 142 . The angle between the line and the vertical axis (A) is the first angle (

) is called second angle (

) is a line connecting the center of the motor 630 and the position P2 where the straight line connecting the center of the second cooling pipe 240 and the second front hole 242 touches the front coil 142 and the vertical axis It is the angle formed by (A). first angle (

) and the second angle (

) corrects the size of the first front hole 222 and the second front hole 242 according to the size change coefficient (k) only when the preset angle value is satisfied. As a non-limiting example, the first angle (

) and the second angle (

) may be 18°, respectively, and the value of k at that time is 1.2.

According to some modifications of the present invention, the above-mentioned effect can be obtained through the increase or decrease of the number of injection holes without changing the size of the injection holes.

Referring to FIGS. 6A and 6B , a third front hole 242 ′ may be perforated together with the second front hole 242 through which most of the oil penetrates into the front coil 142 . This will be apparent to those skilled in the art that the same can be applied to the rear side of the motor 630, and the overlapping description will be omitted.

According to the present invention, the cooling performance of the driving motor can be improved in the same LPM situation. Under the same supply oil amount, a higher LPM cooling effect can be obtained than at the same LPM by reducing the amount of oil hit and thrown away by the coil and increasing the amount of oil used for cooling. For example, if the diameter of the first front hole 222 is reduced by 70% compared to the existing one and the diameter of the second front hole 242 is increased correspondingly, the amount of wasted oil is reduced by 50% or more, and the reduced amount is cooled The effect used for The increased amount of effective cooling oil flows down the wall of the core and penetrates well into the inside of the coil where heat is severe, helping to cool the inside of the coil. As a result, stability can also be secured from breakdown of insulation of the motor stator and demagnetization of the rotor magnet due to the increase in cooling performance. Therefore, it is possible to reduce the replacement cost due to the motor demagnetization failure.

According to the present invention, vehicle running performance is improved. When the temperature sensor detects overheating of the motor due to an increase in the coil temperature and the overtemperature protection logic is executed, the driving output performance of the motor is degraded due to de-rating. However, according to the present invention, the amount of oil injected to the stator with the same LPM is the same, and the cooling performance of the inside of the stator and the rotor is improved by allowing the oil to additionally permeate into the coil. Therefore, according to the present invention, the degree of freedom from the motor output limitation is increased, thereby making it possible to exhibit more stable driving performance.

According to the present invention, it is possible to increase the travel distance. Improved cooling performance means that the cooling oil absorbs more heat from the motor to be cooled. In other words, in the injection structure of the present invention, the motor temperature is reduced and the cooling oil temperature is increased compared to the conventional structure. As a result, the loss is reduced due to the reduction of current and copper loss due to the decrease in the temperature of the motor, and thus the driving distance is increased. In addition, as the viscosity decreases due to an increase in the temperature of the cooling oil, the loss (drag) applied to the reducer is reduced, and thus, the efficiency is increased at both the motor and the reducer, and an effect of increasing the mileage is provided.

The present invention described above is not limited by the above-described embodiments and the accompanying drawings, and it is common in the technical field to which the present invention pertains that various substitutions, modifications and changes can be made within the scope without departing from the technical spirit of the present invention. It will be clear to those who have the knowledge of

100: stator 120: stator core
140: coil 142: front side coil
144: rear side coil 200: cooling pipe
220: first cooling pipe 222: first front hole
224: first rear hole 240: second cooling pipe
242: second front hole 242': third front hole
244: second rear hole 500: coolant system
510: vehicle cooling system 520: inverter
600: cooling oil system 610: electric oil pump
620: heat exchanger 630: motor
640: cooling pipe 650: reducer
660: oil filter 670: temperature sensor

Claims (10)

a motor including a stator core and a coil wound around the stator core and formed obliquely from the stator core with respect to an axial direction of the stator core;
a first cooling pipe disposed on one side of the motor to be spaced apart from the coil by a predetermined distance and including a first injection hole configured to inject oil into the coil; and
and a second cooling pipe disposed on the other side of the motor to be spaced apart from the coil by a predetermined distance and including a second injection hole configured to spray oil to the coil,
On the side of the first injection hole, the coil is configured to inject oil to a portion obliquely extending outwardly from the stator core in a direction away from the first injection hole,
At the second injection hole side, the coil is configured to inject oil to a portion obliquely extending toward the stator core in a direction away from the second injection hole,
The cooling oil injection structure in which the size of the second injection hole is larger than the size of the first injection hole. The cooling oil injection structure according to claim 1, wherein the oil supplied to the first cooling pipe and the second cooling pipe is supplied from an electric oil pump of a vehicle. The cooling oil injection structure according to claim 1, wherein the motor is a hairpin type motor. The cooling oil injection structure according to claim 1, wherein the first cooling pipe and the second cooling pipe are symmetrically disposed with respect to the motor. The cooling oil injection structure according to claim 5, wherein the first and second injection holes are respectively disposed in the first cooling pipe and the second cooling pipe to be symmetrical with respect to the motor. The method according to claim 1,
A first angle that is an angle between a line connecting the center of the motor from a position where a straight line connecting the center of the first cooling pipe and the first injection hole is extended to the coil and a vertical axis passing through the center of the motor;
When the second angle is the angle between the line connecting the center of the motor from the position where the straight line connecting the center of the second cooling pipe and the second injection hole is extended to the coil, and the vertical axis passing through the center of the motor,
Even if the first cooling pipe is not symmetrical with respect to the motor, the size of the second injection hole is larger than the size of the first injection hole if the first angle and the second angle are respectively within a preset angle value. A cooling oil injection structure that is formed. The method according to claim 1, Instead of the size of the second injection hole is formed larger than the size of the first injection hole, a plurality of second injection holes are included,
The cooling oil injection structure in which the sum of the sizes of the plurality of second injection holes is greater than the sizes of the first injection holes. a motor comprising a stator core and a coil wound around the stator core;
a first front hole arranged to be spaced apart from the coil by a predetermined distance on one side of the motor, and configured to spray oil to a first front portion of the coil and a first front hole configured to spray oil to a first rear portion of the coil 1 A first cooling pipe including a rear hole; and
A second front hole arranged to be spaced apart from the coil by a certain distance on the other side of the motor and configured to spray oil to a second front part of the coil and a second front hole configured to spray oil to a second rear part of the coil 2 Including a second cooling pipe including a rear hole,
The first front portion is a portion in which the coil projects obliquely outward with respect to the stator core and extends away from the first cooling pipe, and the second front portion is a portion in which the coil is obliquely outwardly with respect to the stator core. It is a part that protrudes and extends toward the second cooling pipe,
the first rear portion is a portion in which the coil projects obliquely outward with respect to the stator core and extends toward the first cooling pipe;
the second rear portion is a portion in which the coil projects obliquely outward with respect to the stator core and extends in a direction away from the second cooling pipe;
The size of the second front hole is larger than the size of the first front hole,
The size of the second rear hole is configured to be smaller than the size of the second rear hole. 9. The method of claim 8,
and a sum of the size of the first front hole and the size of the first rear hole is substantially equal to the sum of the size of the second front hole and the size of the second rear hole. The coil according to claim 1, wherein the coil projects obliquely from the stator core with respect to the axial direction of the stator core, and at least in one of a radial direction, a circumferential direction, and a direction between the radial and circumferential directions of the stator core. The cooling oil injection structure in which it is bent once and then introduced into the stator core at an angle with respect to the axial direction of the stator core.

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