CN114696541A

CN114696541A - Structure for injecting cooling oil

Info

Publication number: CN114696541A
Application number: CN202111149324.8A
Authority: CN
Inventors: 李在炫
Original assignee: Hyundai Motor Co; Kia Corp
Current assignee: Hyundai Motor Co; Kia Corp
Priority date: 2020-12-31
Filing date: 2021-09-29
Publication date: 2022-07-01
Also published as: KR20220096306A

Abstract

A structure for injecting cooling oil, comprising: a motor having a stator core and a coil wound on the stator core, protruding from the stator core and extending obliquely in an axial direction of the stator core; a first cooling pipe installed at a first side of the motor and having a first injection hole to inject oil onto the coil through the first injection hole; and a second cooling pipe installed at a second side of the motor and having a second injection hole injecting oil into the coil, wherein the first injection hole injects the oil into a portion of the coil extending obliquely outward from the stator core in a direction away from the first injection hole, and the second injection hole injects the oil into a portion of the coil extending obliquely toward the stator core in a direction away from the second injection hole.

Description

Structure for injecting cooling oil

Technical Field

The present invention relates to a structure for injecting cooling oil. More particularly, the present invention relates to a structure for injecting cooling oil, which enables cooling oil injected into an electric machine through a cooling pipe to more effectively permeate into a coil of the electric machine.

Background

The eco-friendly vehicle refers to a Hybrid Electric Vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), a Battery Electric Vehicle (BEV), a Fuel Cell Electric Vehicle (FCEV), etc., to which a rechargeable, large-capacity, high-voltage battery is applied.

In these environmentally friendly vehicles, an electric motor driven by electric power using a high-voltage battery plays a key functional role in driving the vehicle. The motor efficiency is about 90% due to losses caused by heat, wind, noise, etc., and the heat, which accounts for about 25% of the losses, causes the temperature of the motor to exceed the allowable temperature. The allowable temperature is an upper limit of a temperature range in which the motor can stably operate. When the temperature of the motor exceeds the allowable temperature, a coil wound on a stator of the motor may be damaged or a permanent magnet contained in a rotor of the motor may be demagnetized due to overheating. Therefore, a cooling system is provided in the motor to operate the motor within an allowable temperature range. The motor also requires miniaturization, high cooling performance to output high power and high efficiency by nature.

Cooling methods of the motor may be classified into a water cooling method, an air cooling method, and an oil cooling method according to the type of coolant used. Further, the cooling method of the motor may be classified into a direct cooling method and an indirect cooling method according to the contact method used. Recently, as cooling performance of a motor becomes more and more important to meet high performance requirements of the motor, a direct oil cooling method showing improved cooling efficiency is mainly used at present.

The direct cooling method is classified into a rotor shaft dispersion method using rotation of a motor, a pumping method using an electric oil pump, and a submerging method using submerging in oil according to an injection method. In recent years, in order to satisfy higher cooling performance, a combination of cooling the stator with an electric oil pump, cooling the rotor by a shaft dispersion method, and immersing in oil is increasingly used.

Recently, various studies on a cooling system of a motor are being vigorously conducted in order to achieve high efficiency of the cooling system. The study may include an optimized design of injection angles, locations, sizes, and numbers of cooling tubes configured to inject oil at a specified pressure. In addition, the shape design of the motor and the housing for optimizing cooling, the improvement of an injection structure for cooling, and the development of a structure for assisting cooling are included.

The information disclosed in this background section is only for enhancement of understanding of the general background of the invention and is not to be taken as an admission or any form of suggestion that this information forms part of the prior art that is known to a person skilled in the art.

Disclosure of Invention

Various aspects of the present invention are directed to provide a structure for injecting cooling oil for a motor, which can improve cooling performance and cooling efficiency.

Various aspects of the present invention are directed to a structure for injecting cooling oil, the structure including: a motor including a stator core and a coil wound on the stator core, wherein the coil protrudes from the stator core and extends obliquely in an axial direction of the stator core; a first cooling pipe installed at a first side of the motor, spaced apart from the coil, and including a first injection hole to inject oil onto the coil through the first injection hole; and a second cooling pipe installed at a second side of the motor, spaced apart from the coil, and including a second injection hole to inject oil onto the coil through the second injection hole, wherein the first injection hole is configured to inject the oil onto a portion of the coil extending obliquely outward from the stator core in a direction away from the first injection hole; the second injection hole is configured to inject oil onto a portion of the coil that extends obliquely toward the stator core in a direction away from the second injection hole; and the diameter of the second injection hole is larger than the diameter of the first injection hole.

In another aspect, aspects of the present invention are directed to a structure for injecting cooling oil, the structure including: a motor including a stator core and a coil wound on the stator core; a first cooling pipe installed at a first side of the motor, spaced apart from the coil by a predetermined distance, and including a first front injection hole injecting oil onto a first front portion of the coil and a first rear injection hole injecting oil onto a first rear portion of the coil; and a second cooling pipe installed at a second side of the motor, spaced apart from the coil by a predetermined distance, and including a second front injection hole injecting oil onto a second front portion of the coil and a second rear injection hole injecting oil onto a second rear portion of the coil, wherein the first front portion is a portion of each of the coils that protrudes obliquely outward from the stator core and then extends in a direction away from the first cooling pipe, and the second front portion is a portion of each of the coils that protrudes obliquely outward from the stator core and then extends in a direction approaching the second cooling pipe; the first rear portion is a portion of each of the coils that projects obliquely outward from the stator core and then extends in a direction approaching the first cooling pipe, and the second rear portion is a portion of each of the coils that projects obliquely outward from the stator core and then extends in a direction away from the second cooling pipe; the diameter of the second front injection hole is larger than that of the first front injection hole; and the diameter of the second rear injection hole is smaller than the diameter of the first rear injection hole.

Other aspects and exemplary embodiments of the invention are discussed below.

The above and other features of the present invention will be discussed below.

The method and apparatus of the present invention have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following detailed description, which together serve to explain certain principles of the present invention.

Drawings

FIG. 1 is a block diagram of a motor cooling system for a vehicle;

fig. 2 is a top view of a hairpin winding machine according to various exemplary embodiments of the invention;

fig. 3 is a front view of a hairpin winding machine according to various exemplary embodiments of the invention;

fig. 4 is a perspective view exemplarily showing a left front portion of the hairpin winding machine shown in fig. 2;

fig. 5 is a perspective view exemplarily showing a right front portion of the hairpin winding machine shown in fig. 2;

fig. 6A is a perspective view exemplarily illustrating a left front portion of the hairpin winding machine shown in fig. 2; and

fig. 6B is a perspective view exemplarily showing a modified example of a right front portion of the hairpin winding motor shown in fig. 2.

It should be understood that the drawings are not necessarily to scale, emphasis instead being placed upon illustrating various preferred features of the principles of the invention. The particular design features of the present invention as disclosed herein, including, for example, particular sizes, orientations, locations, and shapes, will be determined in part by the particular intended application and use environment.

In the drawings, like reference numerals designate identical or equivalent parts throughout the several views.

Detailed Description

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The specific structures or functions described in the exemplary embodiments of the present invention are for illustrative purposes only. Embodiments according to the inventive concept may be implemented in various forms, and it is understood that they may not be construed as being limited to the exemplary embodiments described in the exemplary embodiments, but include all modifications, equivalents, or alternatives falling within the spirit and scope of the invention.

It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element discussed below could be termed a second element without departing from the teachings of the present invention. Similarly, the second element may also be referred to as the first element.

It will be understood that when an element is referred to as being "coupled" or "connected" to another element, it can be directly coupled or connected to the other element or intervening elements may be present. In contrast, it will be understood that when an element is referred to as being "directly coupled" or "directly connected" to another element, there are no intervening elements present. Other expressions that explain the relationship between elements, such as "between", "directly between", "adjacent" or "directly adjacent", should be interpreted in the same way.

Like reference numerals refer to like parts throughout the specification. Also, the terminology used herein is for the purpose of describing various exemplary embodiments only and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises," "comprising," "includes," "including," "has," "having," and the like, when used in the exemplary embodiments, specify the presence of stated features, steps, operations, or elements, but do not preclude the presence or addition of one or more other features, steps, operations, and/or elements.

In the following detailed description, reference is made to various embodiments of the invention, examples of which are illustrated in the accompanying drawings and described below.

Fig. 1 is a block diagram of a motor cooling system for an environmentally friendly vehicle. The motor cooling system operates in cooperation with a cooling water system 500 of the vehicle. In the cooling water system 500 of the vehicle, cooling water supplied from the vehicle cooling system 510 including an electric water pump and a radiator cools the inverter 520 and then circulates to the vehicle cooling system 510 via the heat exchanger 620.

In the cooling oil system 600, when the electric oil pump 610 pumps oil by applying pressure to the oil, the oil starts to circulate. The oil in the heat exchanger 620 exchanges heat with the cooling water of which the temperature of the cooling water system 500 is relatively low, so that the temperature of the oil is lowered. Then, the oil having a lower temperature is injected into the motor 630 through the cooling pipe 640, thereby reducing the temperature of the motor 630.

After cooling the motor 630, the oil flows to the decelerator 650 and cools the decelerator 650 by gear agitation. After cooling the motor 630 and the decelerator 650, the oil is filtered through an oil filter 660 to remove impurities from the oil, and then returned to the electric oil pump 610 for recirculation. The motor cooling system has a temperature sensor 670, the temperature sensor 670 being configured to measure a temperature of the oil that has passed through the oil filter 660, a temperature of the oil that has passed through the heat exchanger 620, and a temperature of the motor 630 to detect respective temperatures of the oil.

According to various exemplary embodiments of the present invention, the motor 630 may be more effectively cooled by a structure for injecting cooling oil, which is configured to inject an optimal amount of oil from the cooling pipe 640 in consideration of the coil of the motor 630.

The structure for injecting cooling oil according to various exemplary embodiments of the present invention may minimize the amount of oil injected into the coil of the motor 630 through the cooling tube 640 but not wasted for cooling due to the coil shape. Accordingly, the structure according to various exemplary embodiments of the present invention may maximize the effective amount of oil for cooling the motor 630.

Hereinafter, a structure for injecting cooling oil for a motor according to various exemplary embodiments of the present invention will be described in more detail with reference to fig. 2 to 6B.

The motor 630 includes a stator 100 and a rotor. The stator 100 includes a stator core 120 and a coil 140. The coil 140 is wound on the stator core 120, and the stator 100 is coupled to the inside of the motor housing. The permanent magnets are installed along the circumference of the rotor, and the rotor is disposed inside the stator 100. That is, the motor 630 may be a Permanent Magnet Synchronous Motor (PMSM).

According to various exemplary embodiments of the invention, the motor 630 may be a hairpin winding motor. Generally, motors can be classified into various types according to a winding method of a coil. In these types, the hairpin winding machine is configured such that the coil frames are arranged at both end portions of the stator core 120 at an inclination angle, as shown in fig. 2. Each coil 140 protrudes outward from each end of the stator core 120. According to various exemplary embodiments of the present invention, the coil 140 protruding from the front end portion of the stator core 120 and the coil 140 protruding from the rear end portion of the stator core 120 include regions inclined in the same direction thereof when viewed from the front or rear of the motor 630. For example, if the coil 140 at the front end portion of the stator core 120 protrudes from the stator core 120 obliquely in the clockwise direction based on the axial direction of the stator core 120, the coil 140 at the rear end portion of the stator core 120 enters the stator core 120 obliquely in the clockwise direction thereof, viewing the front portion of the motor 630 from the rear portion of the motor 630.

According to various exemplary embodiments of the present invention, the coil 140 of the motor 630 protrudes from the stator core 120 obliquely with respect to the axial direction of the stator core 120. The coil 140 obliquely protruding from the stator core 120 is bent at least once in the radial and circumferential directions of the stator core 120 and in at least one of the radial and circumferential directions thereof, respectively. Thereafter, the bent coils 140 enter the stator core 120 obliquely with respect to the axial direction of the stator core 120.

The oil is supplied to the coil 140 through the cooling pipe 200. The cooling pipe 200 supplies the motor 630 with oil pumped by the electric oil pump 610. In more detail, a plurality of injection holes are formed through the cooling pipe 200. Oil is injected into the coil 140 through the injection hole.

Here, due to the inclined shape of the coil 140, some of the oil supplied through the cooling pipe 200 hits the coil 140 and bounces from the coil 140 to the outside without penetrating the coil 140, which may be referred to as a slop phenomenon.

Since oil waste occurs when the injected oil hits the coil 140 and thus bounces from the coil 140 to the outside of the coil 140 or the motor case, the amount of oil actually used to cool the motor 630 is reduced compared to the amount of oil supplied. Therefore, the cooling efficiency is lowered. The current problem occurs not only when the oil amount is high (e.g., 10 Liters Per Minute (LPM)), but also when the oil amount is low (e.g., 4 to 6 LPM). Therefore, a solution to the slop phenomenon is required.

Accordingly, in various exemplary embodiments of the present invention, the size of the injection holes of the cooling pipe 200 disposed to face each other is adjusted in consideration of the shape of the coil 140. Considering the shape of the coil 140, the amount of oil permeated into the coil 140 can be increased by reducing the diameter of the hole in the cooling tube 200 through which the injected oil is expected to bounce from the coil 140 to the outside and increasing the diameter of the hole in the cooling tube 200 facing thereto.

The cooling tube 200 may have any of various shapes, such as a straight shape, a circular shape, or a combined shape. Further, no cooling pipe 200 may be provided, or a plurality of cooling pipes 200, such as at most three cooling pipes 200, may be provided. Generally, two cooling pipes 200 are used because oil can be uniformly supplied to the left and right portions of the motor 630.

In various exemplary embodiments of the present invention, a pair of cooling pipes 200, which are provided at left and right portions of the motor 630, are provided by way of example. The cooling pipe 200 may be disposed above the motor 630.

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

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

The second cooling pipe 240 includes a plurality of injection holes. The second cooling duct 240 may include a second front injection hole 242 disposed at a front of the motor 630 and a second rear injection hole 244 disposed at a rear of the motor 630.

According to various exemplary embodiments of the present invention, the first and second front injection holes 222 and 242 are symmetrical to each other with respect to the motor 630. That is, the injection angle of the first front injection holes 222 is substantially the same as the injection angle of the second front injection holes 242.

In addition, the first and second rear injection holes 224 and 244 are symmetrical to each other with respect to the motor 630. That is, the injection angle of the first rear injection holes 224 is substantially the same as the injection angle of the second rear injection holes 244.

However, the first cooling pipe 220 and the second cooling pipe 240 may not be identical to each other. In addition, the first and second front injection holes 222 and 242 or the first and second rear injection holes 224 and 244 may not be completely symmetrical to each other. Accordingly, if an angle condition, which will be described below, is satisfied, the size of the corresponding injection hole may vary in various exemplary embodiments of the present invention.

Referring to fig. 4 and 5, after the oil injected through the first front injection hole 222 in the region of the front side coil 142 is in contact with the front side coil 142, the oil moves to the outside of the front side coil 142 or in a direction away from the stator core 120. Alternatively, the oil injected through the first front injection hole 222 is injected onto a portion of the front side coil 142 that protrudes obliquely outward from the stator core 120 and then extends in a direction away from the first cooling pipe 220, when viewed from the first front injection hole 222. Therefore, the oil bounces in a clockwise direction obliquely to a line from the first front injection hole 222 to the front side coil 142, and the oil comes into contact with the front side coil 142 (indicated by a dotted line of fig. 4).

On the other hand, after the oil injected through the second front injection holes 242 in the region of the front side coil 142 comes into contact with the front side coil 142, the oil moves to the inside of the front side coil 142 or moves in a direction approaching the stator core 120. Alternatively, the oil injected through the second front injection holes 242 moves obliquely toward the stator core 120 as viewed from the second front injection holes 242 and is sprayed onto a portion of the front side coil 142 extending in a direction away from the second cooling pipe 240. That is, the oil moves toward the front side coil 142 in a clockwise direction inclined to a line from the second front injection hole 242 to the front side coil 142, and the oil comes into contact with the front side coil 142 (indicated by a dotted line of fig. 5).

Therefore, in this case, it may be predicted that a great loss of oil supplied from the first front injection holes 222 of the first cooling pipe 220 may occur. In this specification, the coil 140 protruding from the front end portion of the stator core 120 will be referred to as a front side coil 142, and the coil 140 protruding from the rear end portion of the stator core 120 will be referred to as a rear side coil 144.

According to various exemplary embodiments of the present invention, the diameter of the first front injection holes 222 is smaller than the diameter of the second front injection holes 242. Since the amount of oil injected through the second front injection holes 242 is increased, the second front injection holes 242 may provide higher cooling performance and higher cooling efficiency at the same flow rate (LPM).

In the case of the front side coil 142, the following equation 1 may be satisfied.

[ equation 1]

d_f2＝k·d_f1

Here, d_f2Is the diameter of the second front injection hole 242, d_f1Is the diameter of the first front injection hole 222. K, which is a size change coefficient, may vary depending on environmental conditions, and may preferably be 1 to 1.5, preferably 1.2. The environmental conditions may include whether the process dimensions are variable and may include a cooling environment.

As described above, when the front side coil 142 extends in a direction away from the stator core 120 at an angle in the counterclockwise direction based on the axial direction of the stator core 120 when viewed from the rear of the stator core 120, the rear side coil 142 extends toward the stator core 120 at an angle in the counterclockwise direction based on the axial direction of the stator core 120. Therefore, the rear side coil 144 is in a reverse condition to the front side coil 142. The oil injected through the second rear injection hole 244 of the second cooling pipe 240 is bounced to the outside from the rear side coil 144, and the oil injected through the first rear injection hole 224 of the first cooling pipe 220 enters the rear side coil 144. In this case, therefore, the diameter of the first rear injection hole 224 is greater than the diameter of the second rear injection hole 244, as shown in the following equation 2.

[ equation 2]

d_r1＝k·d_r2

Here, d_r1Is the diameter of the first rear injection hole 224, d_r2Is the diameter of the second rear injection hole 244.

Further, although the sizes of the first front injection holes 222, the second front injection holes 242, the first rear injection holes 224, and the second rear injection holes 244 are varied, the amount of oil injected through each cooling pipe 200 and the injection pressure may be maintained to be the same. That is, as shown in the following equation 3, the diameter of the first rear injection hole 224 of the first cooling pipe 220 is increased by as much as the diameter of the first front injection hole 222 is decreased. In addition, the diameter of the second rear injection holes 244 of the second cooling pipe 240 is reduced as much as the diameter of the second front injection holes 242. Therefore, the amount and injection pressure of the oil injected through the first and

second cooling pipes

220 and 240 may be maintained the same.

[ equation 3]

Accordingly, the structure for injecting cooling oil according to various exemplary embodiments of the present invention may provide improved cooling performance and efficiency at the same flow rate (LPM) as compared to the conventional structure for injecting cooling oil.

As described above, the cooling pipes 200 may not be completely symmetrical to each other with respect to the motor 630. The positions of the injection holes formed in the respective cooling tubes 200 may not be completely symmetrical to each other. The upper range of the coil 140 may be unclear. Therefore, according to various exemplary embodiments of the present invention, if a predetermined angle condition is satisfied, the same position of the injection hole cooling motors 630 disposed to face each other is determined. When the same position of the injection hole cooling motor 630 disposed to face each other is determined, the size of the injection hole may be changed.

Referring to fig. 3, the angle between the vertical axis a and a line connecting P1 and C may be referred to as a first angle θ₁Where P1 is a point where a straight line configured to connect the center portion of the first cooling pipe 220 to the first front injection hole 222 contacts the front side coil 142, and C denotes a center portion point of the motor 630. The angle between vertical axis A and a line connecting P2 and C may be referred to as a second angle θ₂Where P2 is a point where a straight line configured to connect the center portion of the second cooling pipe 240 to the second front injection hole 242 contacts the front side coil 142. Only when the first angle theta₁And a second angle theta₂When the predetermined angle value is satisfied, the sizes of the first and second front-

injection holes

222 and 242 are corrected according to the size variation coefficient k. For example, the first angle θ₁And a second angle theta₂May be a predetermined angle value, i.e. 18 deg., and in the present case the size change factor k may be 1.2.

According to some modified examples of the present invention, the above-described effects can be obtained by increasing or decreasing the number of injection holes without changing the size of the injection holes.

Referring to fig. 6A and 6B, together with the second front injection holes 242 configured to enable most of the oil to permeate into the front side coil 142, the third front injection holes 242' may be formed through the second cooling pipe 240 by punching. Those skilled in the art will understand that such a structure is applied to the rear of the motor 630, and thus a detailed description of the application of the structure to the rear of the motor 630 will be omitted.

The structure for injecting cooling oil according to various exemplary embodiments of the present invention may improve the cooling performance of the motor 630 at the same flow rate (LPM). By reducing the amount of oil bouncing off and lost from the coil 140 and increasing the amount of oil actually used for cooling, the cooling effect normally achieved at higher LPMs can be achieved at the same oil amount at the same LPM. For example, when the diameter of the first front injection hole 222 is reduced to 70% compared to its existing diameter and the diameter of the second front injection hole 242 is increased by as much as the reduction amount, the amount of oil lost is reduced by 50% or more and such oil amount may be used for cooling. An increased effective amount of oil for cooling flows down the wall of the stator core 120 and penetrates into the coils 140, which dissipates a significant amount of heat, effectively helping to cool the interior area of the coils 140. Therefore, due to the improvement of the cooling performance, it is also possible to ensure the ability to prevent dielectric breakdown of the motor stator and demagnetization of the rotor permanent magnet. Therefore, the replacement cost of the motor due to demagnetization thereof can be reduced.

The structure for injecting cooling oil according to various exemplary embodiments of the present invention improves the drivability of the vehicle. When the temperature sensor detects that the motor 630 is overheated due to the temperature increase of the coil 140, thereby executing logic for protecting the motor 630 from overheating, the driving power performance of the motor 630 is reduced due to derating. However, in the structure for injecting cooling oil according to various exemplary embodiments of the present invention, the amount of oil injected into the stator is the same, and an additional amount of oil permeates into the coil at the same flow rate (LPM). Accordingly, cooling performance with respect to the interior of the stator 100 and the rotor is improved. The structure for injecting cooling oil according to various exemplary embodiments of the present invention increases the degree of freedom of derating and may cause the vehicle to exhibit more stable drivability.

The structure for injecting cooling oil according to various exemplary embodiments of the present invention may increase the driving range of a vehicle. An increase in cooling performance means that the cooling oil absorbs more heat from the machine, which is the target of cooling. That is, the structure for injecting cooling oil according to various exemplary embodiments of the present invention may reduce the temperature of the motor and increase the temperature of the cooling oil, as compared to the conventional structure. Therefore, as the motor temperature decreases, the current and copper losses decrease and the mileage of the vehicle increases. Further, since the viscosity of the cooling oil is reduced due to the increase in the temperature of the cooling oil, the loss caused by the resistance applied to the reduction gear is reduced. Therefore, the efficiency of both the motor and the decelerator is improved, so that the driving range of the vehicle can be increased.

As apparent from the above description, various aspects of the present invention are directed to providing a structure for injecting cooling oil, which has excellent cooling performance and excellent cooling efficiency.

For convenience in explanation and accurate definition in the appended claims, the terms "upper", "lower", "inner", "outer", "upper", "lower", "upward", "downward", "front", "rear", "back", "inner", "outer", "inward", "outward", "inner", "outer", "forward" and "rearward" are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures. It will be further understood that the term "connected" or derivatives thereof refer to both direct and indirect connections.

The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and its practical application to enable others skilled in the art to make and utilize various exemplary embodiments of the invention and various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the following claims and their equivalents.

Claims

1. A structure for injecting cooling oil, the structure comprising:

a motor including a stator core and a coil wound on the stator core, wherein the coil protrudes from the stator core and extends obliquely in an axial direction of the stator core;

a first cooling pipe installed at a first side of the motor, spaced apart from the coil, and including a first injection hole to inject oil onto the coil through the first injection hole; and

a second cooling pipe installed at a second side of the motor, spaced apart from the coil, and including a second injection hole to inject oil onto the coil through the second injection hole,

wherein the first injection hole is configured to inject oil onto a portion of the coil extending obliquely outward from the stator core in a direction away from the first injection hole,

wherein the second injection hole is configured to inject oil onto a portion of the coil that extends obliquely toward the stator core in a direction away from the second injection hole, and

wherein a diameter of the second injection hole is larger than a diameter of the first injection hole.

2. The structure according to claim 1, wherein the oil injected through the first cooling pipe and the second cooling pipe is supplied from an electric oil pump of a vehicle, the electric oil pump being fluidly connected to the first cooling pipe and the second cooling pipe.

3. The structure of claim 1, wherein the motor is a hairpin winding motor.

4. The structure according to claim 1, wherein the first cooling pipe and the second cooling pipe are disposed to be symmetrical to each other with respect to the motor.

5. The structure according to claim 1, wherein the first injection hole and the second injection hole are provided in the first cooling pipe and the second cooling pipe, respectively, so as to be symmetrical to each other with respect to the motor.

6. The structure of claim 1, wherein the first and second electrodes are arranged in a single plane,

wherein the first angle is formed by a line connecting a virtual straight line connecting the center portion of the first cooling pipe to the first injection hole to a position of the coil and a center portion of the motor and a vertical axis passing through the center portion of the motor,

wherein the second angle is formed by a line connecting a virtual straight line connecting the center portion of the second cooling pipe to the second injection hole, extending to a position of the coil and the center portion of the motor, and a vertical axis passing through the center portion of the motor,

wherein a diameter of the second injection hole is larger than a diameter of the first injection hole if each of the first angle and the second angle is within a predetermined angle value even when the first cooling pipe and the second cooling pipe are asymmetrical to each other with respect to the motor.

7. The structure of claim 1, wherein the first and second electrodes are arranged in a single plane,

wherein the second cooling pipe includes a plurality of second injection holes, and

wherein a sum of diameters of the second injection holes is greater than a diameter of the first injection hole.

8. The structure of claim 1, wherein the first and second electrodes are arranged in a single plane,

wherein the first injection hole is plural, including a first front injection hole provided at a front of the motor and a first rear injection hole provided at a rear of the motor.

9. The structure of claim 1, wherein the first and second electrodes are arranged in a single plane,

wherein the second injection hole is plural, including a second front injection hole provided at a front of the motor and a second rear injection hole provided at a rear of the motor.

10. A structure for injecting cooling oil, the structure comprising:

a motor including a stator core and a coil wound on the stator core;

a first cooling pipe installed at a first side of the motor, spaced apart from the coil by a predetermined distance, and including a first front injection hole injecting oil onto a first front portion of the coil and a first rear injection hole injecting oil onto a first rear portion of the coil; and

a second cooling pipe installed at a second side of the motor, spaced apart from the coil by a predetermined distance, and including a second front injection hole injecting oil onto a second front portion of the coil and a second rear injection hole injecting oil onto a second rear portion of the coil,

wherein the first front portion is a portion of each of the coils that projects obliquely outward from the stator core and then extends in a direction away from the first cooling tube, and the second front portion is a portion of each of the coils that projects obliquely outward from the stator core and then extends in a direction approaching the second cooling tube,

wherein the first rear portion is a portion of each of the coils that projects obliquely outward from the stator core and then extends in a direction approaching the first cooling pipe, and the second rear portion is a portion of each of the coils that projects obliquely outward from the stator core and then extends in a direction away from the second cooling pipe,

wherein the diameter of the second front injection hole is larger than the diameter of the first front injection hole, and

wherein the second rear injection hole has a diameter smaller than that of the first rear injection hole.

11. The structure of claim 10, wherein a sum of diameters of the first front injection hole and the first rear injection hole is the same as a sum of diameters of the second front injection hole and the second rear injection hole.

12. The structure according to claim 1, wherein the coil protrudes from the stator core obliquely with respect to an axial direction of the stator core, is bent at least once in at least one of a radial direction and a circumferential direction of the stator core and the radial direction and the circumferential direction, respectively, and then enters the stator core obliquely with respect to the axial direction of the stator core.

13. The structure of claim 10, wherein the first and second electrodes are electrically connected to each other,

wherein the first angle and the second angle are within a predetermined angle value.