KR102575965B1 - Stator having improved cooling efficiency - Google Patents

Abstract

According to the present invention, since the heat transfer area between the refrigerant and the stator is increased compared to the prior art and the cross-sectional area of the passage between the high-temperature part and the refrigerant inlet part can be increased, the stator can be efficiently cooled.

Description

Stator having improved cooling efficiency}

The present invention relates to a stator with improved cooling efficiency, and more specifically, a heat transfer area between a refrigerant and a stator is increased than before, and a flow path area is increased at a high temperature part, a refrigerant inlet part, or a part where the refrigerant flow is more important than the heat transfer area. It is for a stator that can be cooled efficiently because it can be increased.

In general, an electric motor generates rotational motion by receiving electric energy, and includes a stator and a rotor. The stator and rotor are manufactured by manufacturing a single sheet and then stacking several of them.

The stator and rotor generate heat during operation, and when the stator and rotor become hot, their performance deteriorates. Therefore, for normal operation of the electric motor, heat generated from the stator and the rotor must be effectively removed.

In order to remove heat from the stator, a method of cooling the stator by installing a housing surrounding the stator and injecting and circulating a refrigerant in a space between the housing and the stator has been proposed.

However, this method has a problem in that the manufacturing process is complicated and the unit price of the product is high because the housing must be separately manufactured and installed.

In order to solve this problem, a method of forming a refrigerant passage directly in the stator has been proposed. In this method, after forming a through hole in each sheet, the through holes of the upper and lower layers are stacked so that the through holes are connected to each other to form a vertical flow path. The refrigerant cools the stator by exchanging heat with its surroundings while moving vertically along the vertical flow path.

However, this method has a problem in that the cooling efficiency is not high because the heat transfer area between the refrigerant and the stator is not sufficient. In order to solve this problem, if the cross-sectional area of the through hole (flow path) is increased, there are problems that it is very difficult to manufacture in a press process and that the electromagnetic characteristics of the stator are affected.

The present invention has been proposed to solve the above problems, and an object of the present invention is to provide a stator with improved cooling efficiency because a heat transfer area between a refrigerant (eg, oil) and a stator is increased compared to the prior art.

Another object of the present invention is to provide a stator in which cooling efficiency is improved and refrigerant input resistance is reduced because the passage area can be increased in the high temperature part, the part where the refrigerant flows in, or the part where the flow of the refrigerant is more important than the heat exchange area. there is

In order to achieve the above object, the stator 100 according to a preferred embodiment of the present invention includes a first sheet 10 having a first through hole 11 at a first interval g1 at an edge along the circumferential direction; and a second sheet 20 in which second through holes 21 are formed along the circumferential direction at a first interval g1 on the edge.

The width of the first and second through holes 11 and 21 in the circumferential direction is longer than the first interval g1. The first and second sheets 11 and 21 are alternately stacked, and the first through hole 11 of the upper layer is connected to and communicated with the at least two second through holes 21 of the lower layer. The refrigerant moves through the first and second through holes 11 and 21 and exchanges heat to cool the stator.

The stator 100 may include reverse yokes 12 formed at predetermined angular intervals around the center. When dividing the distance D between the end of the reverse yoke 12 and the outer surface of the stator into three equal parts, the first and second through holes 11 and 21 are preferably formed at the outermost parts of the three equal parts.

The first and second through holes 11 and 21 have the same width w1 in the circumferential direction, and the first through hole 11 on the upper layer is connected to the two second through holes 21 on the lower layer. can be layered. The refrigerant may cool the surroundings while moving in the longitudinal and transverse directions through the first and second through holes 11 and 21 .

It is preferable that the first interval (g1) of the first and second sheets (10) (20) is the same. The first gap g1 may be 2.5 mm to 5 mm, and the radial length LR1 of the first and second through holes 11 and 21 may be 2 mm to 6 mm.

The stator 100 includes a third sheet 30 in which third through holes 31 are formed at a second interval g2 at an edge along the circumferential direction; and a fourth sheet 40 in which fourth through holes 41 are formed at a second interval g2 on the edge along the circumferential direction.

When dividing the distance D between the end of the reverse yoke 12 and the outer surface of the stator into three equal parts, the third and fourth through holes 31 and 41 are preferably formed at the outermost parts of the three equal parts.

The width w2 of the third and fourth through holes 31 and 41 in the circumferential direction is greater than the width w1 of the second spacing g2 and the first and second through holes 11 and 21 in the circumferential direction. , the second interval g2 is shorter than the first interval g1.

The third and fourth sheets 30 and 40 may be alternately stacked, so that the third through hole 31 of the upper layer is connected to and communicates with the at least two fourth through holes 41 of the lower layer. Through the third and fourth through-holes 31 and 41, the refrigerant can cool the surroundings while moving in the longitudinal and transverse directions.

The passage cross-sectional area formed by the third and fourth through holes 31 and 41 is larger than the passage cross-sectional area formed by the first and second through holes 11 and 21 . Therefore, the third and fourth sheets 30 and 40 are stacked in the high temperature part of the stator and / or the part where the refrigerant flows into the stator, and the first and second sheets 10 are stacked in the remaining part except for the high temperature part. 20) can be stacked. The third and fourth through-holes 31 and 41 in the high-temperature part and the first and second through-holes 11 and 21 in the remaining part are connected so that the refrigerant can move.

The present invention has the following effects.

First, the cooling efficiency is improved because the heat transfer area between the refrigerant and the stator is increased. In addition, since the refrigerant moves through the passage, it forms not only a vertical flow but also a lateral (spiral) vortex, so that the cooling efficiency is improved.

Second, since the cross-sectional area of the passage can be increased in the high-temperature part of the stator, the part where the refrigerant flows into the stator and the pressure is high, or the part where the refrigerant flow is more important than heat exchange, the cooling efficiency is improved, the refrigerant input resistance is reduced, and the refrigerant may spread more evenly.

Third, it has price competitiveness because it can be manufactured at the same unit price as a stator with a vertical flow path.

1 is a perspective view showing a stator according to a preferred embodiment of the present invention;
2 is an exploded perspective view showing a laminated structure of first and second sheets constituting part A of the stator;
3 is an enlarged view of part III of FIG. 2;
Figure 4 is a plan view showing a first sheet.
5 is an enlarged view of a portion V of FIG. 4;
6 is a cross-sectional view showing a refrigerant flow path of a stator formed by stacking first to fourth sheets.
7 is an enlarged view of part VII of FIG. 6;
8 is a cross-sectional view of a stator in contrast to the present invention, showing that a refrigerant passage is formed in a vertical direction.
9 is an exploded perspective view showing a laminated structure of third and fourth sheets constituting part B of the stator;
Fig. 10 is an enlarged view of part X of Fig. 9;
Figure 11 is a plan view showing a third sheet.
Fig. 12 is an enlarged view of part XII of Fig. 11;

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. Prior to this, the terms or words used in this specification and claims should not be construed as being limited to ordinary or dictionary meanings, and the inventor appropriately uses the concept of terms in order to explain his/her invention in the best way. It should be interpreted as a meaning and concept consistent with the technical idea of the present invention based on the principle that it can be defined. Therefore, since the embodiments described in this specification and the configurations shown in the drawings are merely embodiments of the present invention and do not represent all of the technical spirit of the present invention, various equivalents that can replace them at the time of the present application It should be understood that there may be variations and variations.

1 is a perspective view showing a stator according to a preferred embodiment of the present invention, FIG. 2 is an exploded perspective view showing a laminated structure of first and second sheets constituting part A of the stator, and FIG. 3 is an enlarged view of part III of FIG. 2 it is a drawing

As shown in the drawing, the stator 100 has a portion A formed by alternately stacking the first sheet 10 and the second sheet 20, and the third sheet 30 and the fourth sheet 40 alternately It has part B which is made up of layers. The refrigerant passages of the A part and the B part are connected to each other. Therefore, the refrigerant in part B can move to part A and the refrigerant in part A can move to part B. The refrigerant is preferably a liquid refrigerant, more preferably an oil, but is not necessarily limited thereto.

As is known, the stator 100 is a component constituting an electric motor, and a rotor (not shown) is inserted and installed into a circular cavity therein.

The first sheet 10 includes a first through hole 11 and a reverse yoke 12. And, the second sheet 20 includes a second through hole 21 and a reverse yoke (12). The reverse yoke 12 of the first and second sheets 10 and 20 has the same position and shape. Therefore, when the first and second sheets 10 and 20 are alternately stacked, the reverse yoke 12 of the upper layer completely matches the reverse yoke 12 of the lower layer.

The formation position of the second through hole 21 is different from that of the first through hole 11 . Therefore, when the first and second sheets 10 and 20 are alternately stacked, the first through hole 11 of the upper layer is installed over the plurality of second through holes 21 of the lower layer. This point will be explained in detail below. Preferably, the second through hole 21 is different from the first through hole 11 only in its formation position, and its shape, spacing, size, etc. are the same.

The first through-holes 11 are formed at regular intervals (first interval, g1) along the circumferential direction at the edge of the first sheet 10 (more precisely, a portion adjacent to the outer surface of the first sheet). And, the second through hole 21 is formed at regular intervals (first interval, g1) along the circumferential direction on the edge (more precisely, a portion adjacent to the outer surface of the second sheet 20) of the second sheet 20. The first spacing g1 of the first and second through holes 11 and 21 may be the same.

The first through hole 11 is a hole formed to pass through the first sheet 10, and may be formed by punching during press processing.

As an alternative to the first through-holes 11 formed at a first interval g1, a predetermined angular interval based on the center of the first sheet 10 may be formed at intervals of, for example, 5 °.

It is preferable that the first and second through holes 11 and 21 are formed where they do not affect or minimize the electromagnetic properties of the stator 100 . To this end, when dividing the distance between the outer surfaces of the first and second sheets 10 and 20 from the end of the reverse yoke 12 (D in FIG. 4) into three parts, the first and second through holes 11 and 21 ) is preferably formed in the outermost part of the three equal parts.

The first and second through holes 11 and 21 may have a substantially rectangular shape, preferably a rectangular shape with rounded corners. In this specification, for convenience of explanation, the circumferential width of the first through hole 11 as shown in FIG. Defined as the width measured at the point where the virtual arc (C) and the first through hole (11) meet). This definition is equally applied to the second, third, and fourth through holes 21, 31, and 41 and the first and second gaps g1 and g2. For example, the first distance g1 is a distance measured from the center of the first through hole 11 in the radial direction (see FIG. 5 ).

The circumferential width w1 of the first and second through holes 11 and 21 is longer than the first interval g1. Preferably, the width w1 of the first through hole 11 in the circumferential direction is 3 mm to 8 mm, more preferably the width w1 is 4 mm to 7 mm. If the width w1 is less than 3 mm, the refrigerant cannot sufficiently move, and if the width w1 is greater than 8 mm, the first gap g1 is reduced, resulting in difficulty in manufacturing in the press process.

Meanwhile, the lengths of w1 and g1 may be determined to satisfy the following equation.

If g1 is greater than 80% of w1, the cross-sectional area of the flow path becomes narrow, making it difficult to circulate the refrigerant. This is undesirable as the ability to move laterally may be lacking. However, since the flow of the refrigerant may be more important than the heat exchange area in the B portion, g2 may be smaller than 55% of w2.

And, as shown in FIGS. 6 and 7, when the first sheet 10 and the second sheet 20 are alternately stacked, the first through hole 11 of the upper layer is a plurality of second through holes of the lower layer ( 21) and preferably installed across the two second through holes 21.

According to the same principle, the second through-holes 21 on the upper layer are installed over the plurality of first through-holes 11 on the lower layer, and preferably over the two first through-holes 11 .

Furthermore, the portion 13 between the first through holes in the upper layer corresponds to the center of the second through hole 21 in the lower layer, and the portion 13 is 55 to 80% of the cross-sectional area of the passage of the second through hole 21 in the lower layer and Can be installed overlapping. In addition, the portion 13 is installed to correspond to the center of the second through hole 21 on the upper layer, and the portion 13 is installed to overlap 55 to 80% of the cross-sectional area of the passage of the second through hole 21 on the upper layer. can And, this laminated structure may also be applied between the third and fourth through holes 31 and 41 and the portions 33 and 43.

On the other hand, FIG. 6 is a virtual view in which a cross section cut along the red dotted line (C) in FIG. 1 is spread in a straight line, and the first and second through holes 11 and 21 and the third and fourth through holes ( 31) is for explaining the widths w1 and w2 of (41) and the first and second intervals g1 and g2.

The radial length LR1 of the first and second through holes 11 and 21 is constant, and preferably ranges from 2 mm to 6 mm. When the radial length LR1 is less than 2 mm, the refrigerant is insufficient to sufficiently move, and when the radial length LR1 is greater than 6 mm, the electromagnetic properties of the stator 100 may be affected, which is undesirable.

The first distance g1 is a distance measured along the circumferential direction of the portion 13 between the first and second through holes 11 and 21, and is constant. The first interval g1 is preferably 2.5 mm to 5 mm. When the first gap g1 is smaller than 2.5 mm, the sheet may be deformed due to punching in the press process and the ability to move the refrigerant in the lateral direction is insufficient, which is not preferable. In addition, when the first gap g1 is greater than 5 mm, the width w1 of the first and second through holes 11 and 21 in the circumferential direction becomes relatively small, which is not preferable.

The portion 13 corresponding to the first gap g1 is a portion that is not punched during the press process. The upper and lower surfaces of the portion 13 are portions through which heat is transferred. That is, since the upper and lower surfaces of the portion 13 correspond to the first through hole 11 or the second through hole 21 of the upper and lower layers, they come into contact with the refrigerant and thereby transfer heat to the refrigerant.

In contrast, as shown in FIG. 8 , a refrigerant passage in a vertical direction is formed inside the stator 1 . The refrigerant flow path is formed by stacking through-holes 5 of several sheets 3 to correspond to each other.

The stator 1 is stacked so that the through holes 5 of the upper layer completely correspond to the through holes 5 of the lower layer, and the portion 6 between the through holes 5 also completely corresponds, so that the side surface of the portion 6 Heat transfer is achieved only through the upper and lower surfaces of the portion (6), but no heat transfer is achieved. Therefore, since the stator 1 has a much narrower heat transfer area than the stator 100 and the refrigerant moves only in the vertical direction (longitudinal direction) and cannot move in the horizontal direction (lateral direction), cooling cannot be performed efficiently.

On the other hand, part B is a portion formed by alternately stacking the third sheet 30 and the fourth sheet 40. As will be explained below, part B has a larger passage cross section than part A. Therefore, part B is installed in a part where the temperature rises high in the stator 100, a part where refrigerant flows into the stator, or a part where the pressure is high, and part A can be installed in the remaining parts except for part B. For example, in FIG. 1, part B of the top of the stator is a part that becomes hot when the electric motor operates, and part B of the middle of the stator is a part through which refrigerant flows. The drawing of the inlet through which the refrigerant flows into the refrigerant passage is omitted at part B in the middle of the stator. Refrigerant (oil) flowing into part B in the middle of the stator cools the surrounding area while forming spiral vortex and up-down flow together while moving in the lateral direction due to the wide cross-sectional area of the passage, especially the additionally expanded portions 35 and 45.

Part B has a wider cross section than part A, so the refrigerant can spread more uniformly. Therefore, it is more effective to manufacture a part B with a wider cross-sectional area of the passage in the stator where the high temperature part or the part where the pressure is high due to the inflow of the refrigerant or the part where the flow of the refrigerant is more important than the heat exchange. By adding part B, the cross-sectional area of the passage can be adjusted so that the flow of the refrigerant can be spread more evenly throughout.

As shown in Figures 9 to 12, the third sheet 30 includes a third through hole 31 and a reverse yoke 12. Then, the fourth sheet 40 includes a fourth through hole 41 and a reverse yoke 12. The reverse yoke 12 of the third and fourth sheets 30 and 40 has the same position and shape. In addition, the reverse yoke 12 of the third and fourth sheets 30 and 40 has the same position and shape as the reverse yoke 12 of the first and second sheets 10 and 20. Thus, the reverse yoke 12 of part B completely coincides with the reverse yoke 12 of part A.

The formation position of the fourth through hole 41 is different from that of the third through hole 31 . Therefore, when the third and fourth sheets 30 and 40 are alternately stacked, the third through hole 31 of the upper layer is installed over a plurality of, for example, two fourth through holes 41 of the lower layer. Preferably, the fourth through hole 41 is different from the third through hole 31 only in its formation position, and its shape, interval, etc. are the same.

The third through hole 31 is formed at regular intervals (second interval, g2) along the circumferential direction at the edge of the third sheet 30, more precisely, at a portion adjacent to the outer surface of the third sheet 30. In addition, the fourth through hole 41 is formed at regular intervals (second interval, g2) along the circumferential direction at the edge of the fourth sheet 40, more precisely, at a portion adjacent to the outer surface of the fourth sheet 40 do. The second spacing g2 of the third and fourth through holes 31 and 41 is preferably the same.

The third through hole 31 is a hole formed to pass through the third sheet 30 and may be formed by punching during press processing.

As an alternative to the third through hole 31 formed at the second interval g2, the third through hole 31 is formed at a predetermined angular interval based on the center of the third sheet 30, for example, 5 ° It may be formed at intervals.

The third and fourth through-holes 31 and 41 are preferably formed where they do not affect or minimize the electromagnetic properties of the stator 100 . To this end, when dividing the distance between the outer surfaces of the third and fourth sheets 30 and 40 from the end of the reverse yoke 12 (D in FIG. 11) into three parts, the third and fourth through holes 31 and 41 ) is formed in the outermost part of the three equal parts.

The third and fourth through holes 31 and 41 are rectangular holes with rounded vertices, and both ends in the circumferential direction are additionally punched in an arc shape to expand the holes. Also, the width w2 of the third and fourth through holes 31 and 41 in the circumferential direction is measured including the additionally expanded portions 35 and 45. The additionally punched part may be formed in various shapes such as a rectangular shape as well as an arc shape.

As the width w2 of the third and fourth through holes 31 and 41 in the circumferential direction increases, the passage area increases, but as the width increases, the distance g2 between the through holes decreases and the distance between the through holes decreases. In the face press process, punching is impossible or difficult, and the ability to move the refrigerant (oil) in the lateral direction decreases. In the present invention, to solve this problem, the third and fourth through holes 31 and 41 The above problem was solved while increasing the cross-sectional area of the passage by punching both ends in the circumferential direction in an arc shape.

The width w2 of the third and fourth through holes 31 and 41 in the circumferential direction is longer than the second interval g2. And, the width w2 in the circumferential direction is longer than the width w1. Accordingly, the passage cross-sectional area of the third and fourth through holes 31 and 41 is larger than that of the first and second through holes 11 and 21 .

Preferably, the width w2 is 5 mm to 11 mm. If the width w2 is less than 5 mm, the refrigerant cannot sufficiently move, and if the width w2 is greater than 11 mm, the second gap g2 is excessively reduced, resulting in difficulty in punching in the press process.

And, as shown in FIGS. 6 and 7, when the third sheet 30 and the fourth sheet 40 are alternately stacked, the third through hole 31 of the upper layer is a plurality of fourth through holes of the lower layer ( 41) and preferably installed across the two fourth through-holes 41. According to the same principle, the fourth through hole 41 of the upper layer is installed over the plurality of third through holes 31 of the lower layer, and preferably across the two third through holes 31 .

The radial length LR2 of the third and fourth through holes 31 and 41 is constant, and is preferably equal to the radial length LR1.

The second interval g2 is an interval measured along the circumferential direction of the portions 33 and 43 between the third and fourth through holes 31 and 41, and is constant. The second interval g2 is preferably 1.5 mm to 4 mm. If the second gap (g2) is less than 1.5mm, there is a possibility that the sheet may be deformed due to punching in the press process and the ability to move the refrigerant in the lateral direction is insufficient, and if the second gap (g2) is greater than 4mm, the relatively limited This is not preferable because the circumferential width w2 of the 3 and 4 through holes 31 and 41 becomes small.

The parts 33 and 43 are parts that are not punched in the press process. The upper and lower surfaces of the portions 33 and 43 are portions through which heat is transferred. That is, since the upper and lower surfaces of the portions 33 and 43 correspond to the third through hole 31 or the fourth through hole 41 of the upper and lower layers, they come into contact with the refrigerant and thereby transfer heat to the refrigerant.

Meanwhile, the case where the stator 100 is composed of part A and part B has been described above, but the stator may be made of 'only' part A or 'only' part B. A person of ordinary skill in the art will readily recognize its construction.

1: stator 3: sheet 5: through hole
6: part between through holes 10: first sheet 11: first through hole
12: reverse yoke 13: part between the first through holes
20: second sheet 21: second through hole 23: part between second through holes
30: third sheet 31: third through hole 33: part between third through holes
35: Part where both ends in the circumferential direction of the third through hole are expanded
40: 4th sheet 41: 4th through hole 43: part between 4th through hole
45: Extended portion of both ends in the circumferential direction of the fourth through hole
100: stator
C: Virtual cutting line as a circumferential line passing through the radial center of the first to fourth through holes
D: Distance between the end of the reverse yoke and the outer surface of the 1st to 4th sheets
w1: circumferential width of the first and second through holes
g1: Distance between first through holes, distance between second through holes
w2: width of the third and fourth through holes in the circumferential direction
g2: Distance between the third through holes, distance between the fourth through holes
LR1: Radial length of the first and second through holes
LR2: radial length of the third and fourth through holes

Claims (6)

A first sheet 10 having first through-holes 11 formed at a first interval g1 on the edge along the circumferential direction; and,
A second sheet 20 in which second through-holes 21 are formed at a first interval g1 on the edge along the circumferential direction;
The width of the first and second through holes 11 and 21 in the circumferential direction is longer than the first interval g1, and the first and second sheets 10 and 20 are alternately stacked, and the first through hole of the upper layer (11) is stacked so as to communicate with at least two second through holes 21 of the lower layer,
The refrigerant moves through the first and second through holes 11 and 21 and exchanges heat,
A third sheet 30 in which third through holes 31 are formed at a second interval g2 on the edge along the circumferential direction; and,
A fourth sheet 40 having fourth through-holes 41 formed at the edge at a second interval g2 along the circumferential direction; includes,
When the distance (D) between the end of the reverse yoke 12 and the outer surface of the stator is divided into three equal parts, the third and fourth through holes 31 and 41 are formed at the outermost part of the three equal parts,
The widths of the third and fourth through holes 31 and 41 in the circumferential direction are longer than the second spacing g2 and the widths of the first and second through holes 11 and 21 in the circumferential direction, and the second spacing g2 ) is shorter than the first interval g1,
The third and fourth sheets 30 and 40 are alternately stacked so that the third through hole 31 of the upper layer is connected to and communicated with the at least two fourth through holes 41 of the lower layer,
A stator characterized in that the refrigerant moves in the longitudinal and transverse directions through the third and fourth through holes (31, 41) to cool the surroundings. According to claim 1,
Inverse yokes 12 are formed at predetermined angular intervals centered on the center of the stator,
When the distance (D) between the end of the reverse yoke 12 and the outer surface of the stator is divided into three equal parts, the first and second through holes 11 and 21 are formed at the outermost part of the three equal parts stator . According to claim 2,
The first and second through holes 11 and 21 have the same width w1 in the circumferential direction, and the first through hole 11 on the upper layer is connected to the two second through holes 21 on the lower layer. are laminated,
The stator characterized in that the refrigerant cools the surroundings while moving in the longitudinal and transverse directions through the first and second through holes (11) (21). According to claim 3,
The first spacing g1 of the first and second sheets 10 and 20 is the same, and the first spacing g1 is 2.5 mm to 5 mm,
The stator, characterized in that the radial length (LR1) of the first and second through holes (11) (21) is 2mm ~ 6mm. delete According to claim 1,
The third and fourth sheets 30 and 40 are laminated in the high-temperature part of the stator, and the first and second sheets 10 and 20 are laminated in the remaining parts except for the high-temperature part, and the third and fourth through The channel cross-sectional area formed by the holes 31 and 41 is larger than the channel cross-sectional area formed by the first and second through holes 11 and 21,
The stator characterized in that the refrigerant moves by connecting the third and fourth through holes 31 and 41 of the high temperature part and the first and second through holes 11 and 21 of the remaining part.