JP7151602B2 - Rotating electric machine - Google Patents

Description

The present invention relates to a rotating electric machine having an iron core and windings.

The rotating electrical machine described in Patent Document 1 has a stator core, which is an iron core having a structure in which metal plates are laminated, and a stator coil, which is a winding wound around the stator core. When such a rotating electrical machine operates, the temperature of the rotating electrical machine rises with the heat generation of the stator core and stator coils. Therefore, the rotating electrical machine is usually cooled using air in the rotating electrical machine or cooling oil supplied to the inside of the rotating electrical machine as a cooling medium.

Japanese Patent No. 6459301

Due to the influence of recent improvements in the efficiency of rotating electrical machines, gaps between stator cores and stator coils and between coil wires of stator coils inside rotating electrical machines, that is, gaps through which a cooling medium enters, are becoming smaller. This is one of the factors that hinder the improvement of the cooling efficiency of the rotating electric machine by the cooling medium.

SUMMARY OF THE INVENTION An object of the present invention is to provide a rotating electrical machine capable of improving cooling efficiency.

A rotating electric machine for solving the above problems is a rotating electric machine having an iron core formed by laminating metal plates and a winding wound around the iron core, wherein at least a part of the metal plates constituting the iron core has a shape in which a portion of the metal plate around which the winding is wound is bent in the rotating shaft direction of the rotating electric machine, and the winding has a linear expansion coefficient larger than that of the material forming the iron core. It is made of a material and is wound around the iron core while the iron core is tightened in a direction to flatten the curved portion.

In the above configuration, when the temperature of the rotating electric machine is low, the gap between the metal plates forming the iron core is kept small. When the temperature of the iron core and the windings rises with the operation of the rotating electric machine, the amount of thermal expansion of the windings becomes larger than the amount of thermal expansion of the iron core, so the tightening force of the windings on the iron core becomes weaker. . As a result, the metal plate is restored to its bent state, and a gap is generated between the metal plates forming the iron core. According to the above configuration, such a gap can be used as a gap for cooling the rotating electric machine, more specifically as a gap into which a cooling medium such as air enters. Therefore, it is possible to improve the cooling efficiency of the rotating electric machine.

According to the present invention, it is possible to improve the cooling efficiency.

1 is a side sectional view of a rotary electric machine according to one embodiment; FIG. A perspective view of a stator. The side view which expands and shows the tooth part of a stator, and its periphery. FIG. 4 is a cross-sectional view showing a bent shape of a portion corresponding to a tooth portion of a metal plate; FIG. 4 is a cross-sectional view of the stator taken along line AA of FIG. 3; 4 is a schematic diagram showing the cross-sectional structure of the stator along line BB in FIG. 3; FIG. FIG. 4 is a cross-sectional view along the line AA of FIG. 3 of the stator at high temperature; 4 is a schematic diagram showing the cross-sectional structure of the stator along the line BB in FIG. 3 at high temperature; FIG.

An embodiment of a rotating electrical machine will be described below.
As shown in FIG. 1, an electric motor 10 as a rotating electric machine is a permanent magnet field type synchronous motor, and has a case 13 in which a stator 11 and a rotor 12 are accommodated. The case 13 has a cylindrical case body 14 , a case lid wall 15 closing one opening of the case body 14 , and a case bottom wall 16 closing the other opening of the case body 14 .

A stator 11 of the electric motor 10 has a stator core 20 as an iron core and a stator coil 21 as a winding. The stator core 20 has a substantially cylindrical shape and is fixed inside the case body 14 . A stator coil 21 is wound around a center hole 22 in the stator core 20 . Details of the stator 11 will be described later.

A rotor 12 of the electric motor 10 has a rotor core 30 and a rotor shaft 31 . The rotor core 30 has a cylindrical shape. The rotor shaft 31 is integrated with the rotor core 30 while being inserted through the center hole 32 of the rotor core 30 .

A support hole 33 is provided in the case bottom wall 16 . A cylindrical support tube portion 34 protrudes from the inner surface of the case lid wall 15 . The support hole 33 and the support cylinder portion 34 function as bearings that rotatably support the rotor shaft 31 . In this embodiment, the rotor shaft 31 is supported by the case 13 with one end of the rotor shaft 31 inserted into the support hole 33 and the other end inserted into the support cylinder portion 34 .

An oil through hole 40 is formed in a portion of the upper portion of the case lid wall 15 facing the stator coil 21 . An oil through hole 41 is formed in the upper portion of the case bottom wall 16 facing the stator coil 21 . These oil through holes 40 and 41 function as oil passages through which cooling oil passes.

An oil pump 43 is connected to the electric motor 10 . A suction port of the oil pump 43 is connected to the lower portion of the case 13 , and a discharge port of the oil pump 43 is connected to openings of the oil through holes 40 and 41 on the outer surface of the case 13 .

In the electric motor 10 of this embodiment, oil is accumulated in the lower portion of the case 13 as indicated by dot hatching in FIG. When the oil pump 43 operates during operation of the electric motor 10 , the oil in the lower portion of the case 13 is pumped up by the oil pump 43 , supplied into the case 13 through the oil through holes 40 and 41 , and applied to the stator coil 21 . In this embodiment, the stator 11 is cooled through heat exchange between the oil applied to the stator 11 and the stator 11 in this manner.

A specific structure of the stator 11 will be described below.
As shown in FIGS. 2 and 3, the stator core 20 has a laminated structure in which a plurality of (for example, several hundred) disc-shaped metal plates 23 having a center hole are laminated. The metal plate 23 is made of an electromagnetic steel plate (specifically, a non-oriented silicon steel plate).

The stator core 20 is provided with a plurality of slits 24 having a substantially fan-shaped cross section and penetrating in the rotation axis direction of the electric motor 10 . Each slit 24 has a shape that opens in the inner peripheral surface of the stator core 20 and extends in the radial direction of the stator core 20 . The plurality of slits 24 are arranged at equal intervals in the circumferential direction of the stator core 20 .

The stator coil 21 is of concentrated winding, and has a coil shape wound around portions (teeth portions 25 ) sandwiched between adjacent slits 24 in the stator core 20 . Specifically, the stator coil 21 is wound around the teeth 25 a plurality of times so that the outer cross section of the coil wire arrangement range is substantially rectangular and forms an annular shape around the teeth 25 . A material for forming the stator coil 21 is aluminum, and a coil wire forming the stator coil 21 has a square cross section.

A part of the stator coil 21 of the adjacent slot is arranged inside each slit 24 . Between the two stator coils 21 in each slit 24, a spacer 26 shaped to fill the gap is provided. The spacer 26 is made of an insulating synthetic resin.

As shown in FIG. 4, the portions of the metal plates 23 of the stator core 20 that correspond to the teeth portions 25 project in one direction (upward or downward in FIG. 4) in the direction of the rotation axis. 4) has a curved shape. In FIG. 4, the thickness and the degree of curvature of each metal plate 23 are exaggerated for easy understanding of the bending shape of each metal plate 23 .

The stator core 20 includes a metal plate 23 curved in such a manner that a portion corresponding to the same tooth portion 25 forms a convex shape on one side (upper side in FIG. 4) in the rotation axis direction when the same tooth portion 25 is viewed, The portions corresponding to the tooth portions 25 are laminated in such a manner that the metal plates 23 curved in a convex shape on the other side (lower side in FIG. 4) in the rotation axis direction are arranged alternately.

In the present embodiment, when the stator coil 21 is assembled to the stator core 20, the work of winding the stator coil 21 around the tooth portions 25 of the stator core 20 is performed in the direction of flattening the curved portions of the metal plates 23. It is performed in a manner to tighten the tooth portion 25 . As a result, as shown in FIG. 5, in the stator core 20 of the present embodiment, the portions of the adjacent metal plates 23 corresponding to the tooth portions 25 are elastically deformed and brought into close contact with each other. In addition, in FIG. 5, the thickness of each metal plate 23 is exaggerated in order to facilitate understanding of the shape of each metal plate 23 .

The operation of the electric motor 10 having the stator 11 will be described below.
In this embodiment, the stator coil 21 is provided so as to tighten the tooth portions 25 of the stator core 20 in the stacking direction of the metal plates 23 when the stator coil 21 is assembled to the stator core 20 . As a result, the gap between adjacent metal plates 23 is small. Therefore, as shown in FIGS. 5 and 6, when the temperature of the stator 11 is low, such as when the operation of the electric motor 10 is stopped or when the operation duration is short, the gap between the metal plates 23 forming the stator core 20 is small. be kept. In addition, in FIG. 6, the shape of each metal plate 23 is simplified to facilitate understanding of the shape of each metal plate 23 . At this time, the gap around the teeth 25 of the stator core 20 in the case 13, that is, the gap through which the cooling oil enters becomes smaller. However, since the temperature of the stator 11 is low and the situation does not require a high cooling capacity by the cooling oil, the possibility of insufficient cooling capacity is low.

In the present embodiment, the coefficient of linear expansion of the material (aluminum) forming the stator coil 21 is larger than the coefficient of linear expansion of the material (silicon steel plate) forming the stator core 20 . Therefore, when the temperature of the stator 11 increases as the electric motor 10 operates, the amount of thermal expansion of the stator coil 21 at this time becomes larger than the amount of thermal expansion of the stator core 20 .

Here, both surfaces of the outer circumferential surface of the coil-shaped stator coil 21 on the circumferential direction side of the stator core 20 are in contact with and supported by the spacer 26 . Therefore, deformation of the stator coil 21 in the circumferential direction is suppressed when the stator coil 21 thermally expands. Therefore, when the stator coil 21 thermally expands, the stator coil 21 deforms in a manner that it expands in the rotation axis direction.

As shown in FIGS. 7 and 8, due to the deformation of the stator coil 21, the tightening force of the stator coil 21 in the direction of the rotational axis of the stator core 20 is weakened. and return to a curved state. As a result, gaps are formed between the portions of the adjacent metal plates 23 that contact the tooth portions 25 . According to the present embodiment, such a gap can be used as a gap for cooling the electric motor 10, specifically as a gap into which cooling oil enters. Thereby, improvement of the cooling efficiency of the electric motor 10 can be aimed at.

In FIG. 7, the degree of extension of the stator core 20, the gap between the adjacent metal plates 23, the gap between the metal plate 23 and the stator core 20, and the like are exaggerated in order to facilitate understanding of the gaps generated between the metal plates 23. is shown. In this embodiment, the stator coil 21 actually extends several hundred micrometers more than the stator core 20 in the rotation axis direction. In addition, in FIG. 8, the shape of each metal plate 23 is simplified to facilitate understanding of the shape of each metal plate 23 .

Further, in the present embodiment, when the temperature of the stator 11 increases with the operation of the electric motor 10, the difference in thermal expansion between the stator coil 21 and the stator core 20 causes the difference in thermal expansion between the stator coil 21 and the stator core 20 in the rotation axis direction. the gap becomes larger. According to the present embodiment, the larger the gap, the easier it is for the cooling oil to enter the same gap, so the cooling efficiency of the electric motor 10 can be improved.

According to this embodiment, the following effects can be obtained.
(1) The cooling efficiency of the electric motor 10 can be improved.
(2) The structure of the stator core 20 is composed of a metal plate 23 curved in such a manner that a portion corresponding to the tooth portion 25 forms a convex shape on one side in the rotation axis direction when the same tooth portion 25 is viewed, and the tooth portion 25 The curved metal plates 23 are alternately stacked so that the portion corresponding to the contact point is convex toward the other side in the direction of the rotation axis. Therefore, by providing the stator coil 21 so as to tighten the stator core 20 in the stacking direction of the metal plates 23, each metal plate 23 is elastically deformed, and the gap between the adjacent metal plates 23 can be made small. Moreover, when the clamping force of the stator core 20 on the teeth 25 of the stator core 20 by the stator coil 21 becomes smaller due to the thermal expansion of the stator core 20 and the stator coil 21 due to the temperature rise, the metal plates 23 are restored to the curved state. Become. In this way, the gap between adjacent metal plates 23 can be increased.

(3) A coil wire forming the stator coil 21 has a square cross section. As a result, the coil wires forming the stator coil 21 can be in surface contact with each other. Therefore, the coil wires can be supported in a stable state when the stator coil 21 thermally expands, compared to a stator having a structure in which the coil wires are in line contact (or point contact). Therefore, it is possible to easily manage the position of each coil wire, and thus to easily manage the deformation of the stator coil 21 .

(4) The stator coil 21 is made of aluminum, and the stator core 20 is made of silicon steel plate. Therefore, the difference in the amount of thermal expansion between the stator coil 21 and the stator core 20 can be increased compared to an electric motor that employs copper stator coils. As a result, when the stator 11 thermally expands, the tightening force of the stator core 20 by the stator coil 21 can be easily weakened, so that a gap can be easily generated between the metal plates 23 constituting the stator core 20.

It should be noted that the above embodiment may be modified as follows.
The assembly of the stator coil 21 to the stator core 20 is not limited to the manner in which the portions corresponding to the teeth portions 25 of the adjacent metal plates 23 are brought into close contact with each other. may be performed in such a manner that is free. With this configuration as well, when the stator 11 thermally expands, the gap between the adjacent metal plates 23 can be increased by utilizing the difference in the amount of thermal expansion between the stator core 20 and the stator coil 21 . Since cooling oil can easily enter this gap, the cooling efficiency of the electric motor 10 can be improved accordingly.

- The spacer 26 arranged in the slit 24 may be omitted. In this case, the stator coils 21 are arranged so that the two stator coils 21 arranged in the same slit 24 are in contact with each other and supported by each other, so that the outer cross section of the coil wire arrangement range is substantially trapezoidal. It should be arranged so that

The portions of the metal plate 23 that correspond to the tooth portions 25 may be curved in the circumferential direction of the metal plate 23 instead of being curved in the radial direction of the metal plate 23 .

The configuration in which the portions of the metal plates 23 corresponding to the teeth portions 25 are curved may be applied only to some of the plurality of metal plates 23 .
The bending shape of the portion of the metal plate 23 that corresponds to the tooth portion 25 can be changed to any bending shape as long as it is a shape that bends in the rotation axis direction.

- The stator coil 21 may be provided by winding a coil wire having a circular cross section.
- The material for forming the stator coil 21 may be copper.

・In the rotor of a brush motor having a rotor core as an iron core and a rotor coil as a winding, the metal plate forming the iron core is bent in the direction of the rotation axis, and the bent portion of the metal plate is flattened. A configuration in which the winding is wound while the iron core is tightened in the direction to be applied may be applied.

- The rotary electric machine of the above embodiment can also be applied to a rotary electric machine that cools the stator using the air in the case as a cooling medium.

DESCRIPTION OF SYMBOLS 10... Electric motor 11... Stator 12... Rotor 13... Case 14... Case main body 15... Case lid wall 16... Case bottom wall 20... Stator core 21... Stator coil 22... Center hole 23... Metal Plate 24 Slit 25 Teeth 26 Spacer 30 Rotor core 31 Rotor shaft 32 Center hole 33 Support hole 34 Support cylinder 40, 41 Oil through hole 43 oil pump.

Claims (4)

A rotating electric machine having an iron core formed by laminating metal plates and a winding wound around the iron core,
At least part of the metal plate forming the iron core has a shape in which a portion of the metal plate around which the winding is wound is bent in the direction of the rotating shaft of the rotating electric machine,
The winding is made of a material having a linear expansion coefficient larger than that of the material forming the iron core, and is wound around the iron core in a state where the iron core is tightened in a direction to flatten the curved portion. , rotating electric machine. The iron core includes a metal plate curved in such a manner that a portion around which the winding is wound forms a convex shape on one side in the direction of the rotating shaft, and a portion around which the winding is wound on the other side in the direction of the rotating shaft. 2. The electric rotating machine according to claim 1, wherein the metal plates curved in a convex shape on the side are laminated in a manner alternately arranged. 3. The rotating electric machine according to claim 1, wherein the winding has a square cross section. The electric rotating machine according to any one of claims 1 to 3, wherein the material for forming the windings is aluminum.

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