JP4355555B2 - Rotating electric machine - Google Patents

Description

  The present invention relates to a rotating electrical machine, and more particularly to an improvement in a radial rotating electrical machine characterized in that a stator is directly cooled by a liquid refrigerant.

  In order to reduce the size and increase the performance of a radial rotating electrical machine, a technology that can cope with an increase in heat load is required. In particular, as electric vehicles and hybrid vehicles are being put into practical use, further downsizing and higher performance of rotating electric machines are required.

  Heat generation of the radial type rotating electric machine is generated in a magnetic flux generation region of components such as an iron core and a coil (or a magnet) in a stator and a magnet (or an iron core and a coil) in a rotor. In addition, the iron core around which the coil is wound in the stator (or the rotor) generates a large amount of heat, and its rotational speed dependency is larger than that of the coil, so that the heat generation density increases as the rotation speed increases. Furthermore, since coil heating is also applied to the iron core, the iron core in the vicinity of the coil is highly required to be cooled.

For example, the heat generation density of a rotating electrical machine is (1) 0.1 W / cm ³ or less for a general-purpose motor, (2) increases from 0.2 to 0.6 W / cm ³ from a small and high load motor, (3 ) Motors with high rotation speeds also change to 1-10 W / cm ³ . For the general-purpose motor shown in (1), the air-cooling method currently in practical use is suitable, but in order to reach (2) and (3), a cooling method using liquid is unavoidable.

  Conventionally, several techniques have been disclosed for stator cooling by a liquid refrigerant of a rotating electrical machine represented by a motor. These motors are intended for coaxial cylindrical radial motors, and a refrigerant flow path is provided in the stator. In the motor described in Patent Document 1 below, the refrigerant flow path along the axis is set in the yoke portion of the stator. However, it is assumed that a laminated steel plate is used for the iron core in order to ensure effective magnetic flux. In such a structure using a laminated steel plate, it is difficult to set an arbitrary flow path, and only a flow path parallel to the axis can be set as a refrigerant flow path. In order to construct a closed cooling circuit including a pump and a heat exchanger, a joint for joining a large number of laminated steel plates that form a refrigerant flow path is required. It is difficult to adopt a screw structure. Moreover, in the structure using laminated steel plates, the occurrence of refrigerant leakage is unavoidable and is not practical. In order to improve the leakage of the refrigerant, it is possible to insert a separate channel pipe in the refrigerant channel of the stator. In this case, however, there is a contact thermal resistance between the inner surface of the refrigerant channel and the outer surface of the channel tube. Therefore, the effect of direct liquid cooling is greatly reduced. Therefore, the direct cooling of the stator by the liquid refrigerant in the prior art as in Patent Document 1 below is less feasible.

  Further, Patent Document 2 below discloses an invention in which a groove is formed on the outer peripheral surface of a yoke portion of a radial motor, and a liquid refrigerant channel is formed between the outer casing and the outer casing. In the case of the present invention, the refrigerant flow path is circumferential, and a complicated mechanism is required for the liquid seal installed between the case and the case. Furthermore, in order to avoid interference with the magnetic flux, it is necessary to set a flow path in a region away from the coil, and the effect of direct cooling is reduced (as another similar technique, for example, Patent Document 3 below) reference).

JP 2002-165410 A Japanese Patent Laid-Open No. 08-322170 JP 05-236705 A

  As described in the background art, it is difficult to achieve further downsizing and higher performance of the rotating electrical machine that is required in current electric vehicles, hybrid vehicles, and the like. Therefore, in a radial type rotating electrical machine, a technology to reduce the size and increase the performance of the radial type rotating electrical machine by making it possible to directly cool the stator core having a high calorific value and heat generation density with a liquid refrigerant having a high cooling effect. Was demanded.

  The present invention aims to reduce the size and performance of a radial rotating electrical machine by providing a completely new iron core cooling structure for reducing the size and performance of a radial rotating electrical machine.

A rotating electrical machine according to the present invention is a stationary electric machine in which a rotor that is a field magnetic flux generation source and a plurality of stator coils that generate a rotating magnetic field that rotates the rotor are wound around a plurality of sets of stator cores. In the radial type rotating electric machine including a child, the stator core is a plurality of teeth around which a stator coil is wound, and a back yoke disposed on one end side of the teeth, the stator A back yoke having a flange projecting from the end surface of the tooth in the axial direction of the iron core, and the plurality of teeth and the back yoke are formed of a dust core material, and the back yoke includes a refrigerant therein. A flow path is provided, and the refrigerant flow path is provided in the flange portion that connects the axial direction portion extending in the axial direction of the stator core along the back center of the tooth and the axial direction portion adjacent in the circumferential direction. With the turned part Having.

  On the other hand, in another rotating electrical machine according to the present invention, the stator core is integrally formed of a powder magnetic core material, and the refrigerant flow path is formed over the entire integrally formed stator core. And

  Furthermore, in the rotating electrical machine according to the present invention, the inlet / outlet portion of the refrigerant flow path is provided on a surface other than the coil installation surface of the stator core or a surface other than the rotor side of the stator core. It is characterized by.

  Furthermore, in the rotating electrical machine according to the present invention, a corrosion-resistant film is formed on the wall surface of the refrigerant flow path.

  ADVANTAGE OF THE INVENTION According to this invention, the influence on the performance characteristic of a rotary electric machine can be suppressed, and the stator core with a high emitted-heat amount and a high heat-generation density can be directly cooled by using the liquid with a high cooling effect as a refrigerant | coolant. By increasing the cooling effect in this way, it is possible to provide a rotating electrical machine that achieves downsizing and high performance.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Preferred embodiments for carrying out the invention will be described with reference to the drawings. The technical scope of the present invention is not limited to the scope described in the following embodiments, and various modifications or improvements can be added to the following embodiments. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

  First, the structure of a radial motor to which this embodiment is applied will be described. 1A and 1B are diagrams showing a configuration of a conventional radial motor, where FIG. 1A is a schematic sectional view in the axial direction of the radial motor, and FIG. 1B is a schematic sectional view in the radial direction of the radial motor. .

  The radial motor in the present embodiment includes a cylindrical rotor 10 having a plurality of permanent magnets, a stator 13 having a plurality of poles around which a stator coil 12 is wound around an iron core material (stator core) 11, and Are arranged coaxially. The rotor 10 becomes a field magnetic flux generation source by a permanent magnet, and can be rotated in accordance with a rotating magnetic field generated from the stator 13. On the other hand, the stator 13 is obtained by winding the stator coil 12 around the teeth 11a of the stator core 11. In the case of the radial motor illustrated in FIG. 1, the stator 13 is an 8-pole motor. . A back yoke 11b is disposed on one end (outer side) of the plurality of teeth 11a provided in the stator core 11 so that the plurality of stator coils 12 can be fitted therein. 11 is constituted. That is, the stator 13 is configured by winding a plurality of pairs of stator coils 12 that generate a rotating magnetic field for rotating the rotor 10 around a plurality of sets of stator cores 11. The stator core 11 may be configured as a single stator core 11 as a whole of the pole, or may constitute a core that is divided for each pole, and the stator core 11 is formed as an aggregate of the cores. It is also good to do.

  Furthermore, the stator core formed of the conventional laminated steel sheet will be described in detail. FIG. 2 is a view showing a part of a stator core of a radial motor composed of laminated steel plates. In FIG. 2, the direction of the magnetic flux line 15 which passes the stator core comprised with the laminated steel plate, and the installation area | region 16 of the refrigerant flow path which can be provided by avoiding the magnetic flux line 15 are shown.

  In the stator core 11 of the conventional radial type motor described above, since the laminated steel plates are laminated in the axial direction, the magnetic flux lines 15 generated in the central axis direction of the coil 12 and passing through the stator core 11 are axially directed. It was difficult to get around. This is because the axial magnetic flux path must pass through the laminated surface, increasing the magnetic resistance. This means that due to restrictions on the direction of passage of the magnetic flux lines 15 of the laminated steel stator core 11, the refrigerant flow path installable area 16 provided in the area avoiding the magnetic flux path must be reduced. Is shown. That is, in the stator core 11 made of laminated steel sheets, the path of the magnetic flux lines 15 cannot be set in a direction other than the direction along the laminated steel sheet, so that the refrigerant flow path can be expanded by setting an arbitrary cooling flow path. This shows that it is very difficult to take measures. 2 is a general cooling flow path that is common when a laminated steel plate is used for the stator core of the radial motor.

  Therefore, in the present invention, the stator core that has been conventionally constituted by laminated steel sheets is constituted by a dust core material. A radial motor according to the present embodiment will be described with reference to the drawings.

  FIG. 3 is a diagram showing a part of the stator core when the present invention is applied to a stator core of a radial motor. In FIG. 3, the direction of the magnetic flux line 25 which passes the stator core 23, and the installation possible area | region of the refrigerant flow path 26 which can be provided by avoiding the magnetic flux line 25 are shown. FIG. 4 is a diagram showing a configuration of the radial motor in the present embodiment, (a) is a schematic cross-sectional view in the axial direction of the radial motor, and (b) is a radial cross-section of the radial motor. FIG.

  Here, the powder magnetic core material is an object that is pressure-molded after an electrically insulating film is applied to a fine iron powder material, and is desirable as a block like a bulk material because the insulating materials are pressure-bonded to each other. A product in the form of can be obtained. Since the molded product of the dust core material is an aggregate of fine iron powder as a whole, an arbitrary three-dimensional shape can be formed alone. When viewed macroscopically, there is no electrical or thermal anisotropy, so there is no limitation on the direction of the internal magnetic flux lines, and it has the great feature of enabling three-dimensional deflection of the magnetic flux lines.

  By forming the stator core 23 with the dust core material having such characteristics, the magnetic flux lines 25 are allowed to have three-dimensionality. Therefore, the magnetic flux lines 25 passing from the core are not only in the circumferential direction but also in the axial direction. Will be added. Furthermore, it is possible to increase the magnetic path by adding the additional region 23a provided in a bowl shape in the axial direction, which is meaningless in the laminated steel sheet. Therefore, since all the magnetic flux lines 25 are distributed over the entire axial direction of the iron core, the coolable region 26 on the back surface of the iron core is expanded. 3B and 3C, the refrigerant flow path installable region 26 is shown by comparing the conventional case with the case of the present embodiment, but the refrigerant flow path installation in the present embodiment is shown. It is shown that the possible region 26 extends in the axial direction as well as the circumferential direction when viewed from the back, and can be set deep inside the iron core.

  Thus, according to the present embodiment, the stator core 23 is formed of a dust core material, and the hook-shaped additional region 23a is added to the stator core 23, whereby the magnetic path due to the deflection of the magnetic flux lines 25 is achieved. And the enlargement of the coolable region 26 can be realized. Note that the magnetic flux in the stator core 23 is generated around the stator coil 22 from the stator to the rotor magnet. In the stator core 23, heat is lost according to the magnetic flux, and at the same time, the stator coil 22 itself. Since heat is also generated as a current loss, it is desirable to set the refrigerant flow path 26 in a region surrounding the magnetic flux in the stator core 23. That is, it is preferable to provide the refrigerant flow path 26 in or on the stator core, which is a region that is generated by the stator coil 22 and does not interfere with the dense portion of the magnetic flux lines 25 that pass through the stator core 23.

  Next, a specific configuration of the refrigerant flow path will be described. FIG. 5 is a side view of the flow path setting region 26 of the stator core 23 shown in FIG. 3. FIG. 5 is a cross-sectional view showing the case viewed from the radial direction. FIG. 5 illustrates a single pole, and a refrigerant flow path 26 a that secures a necessary heat removal amount is installed inside the stator core 23. Compared to the conventional stator core 13, a very wide area can be used as the refrigerant flow path 26a. In addition, in this embodiment demonstrated below, the refrigerant | coolant entrance / exit part 27 is made into the surface opposite to the coil 22 installation side, It is characterized by the above-mentioned. This is because a single pole assembly can be taken out between the poles, but convenience is higher on the opposite side of the coil. However, the refrigerant inlet / outlet portion 27 of the refrigerant flow path can be provided on a surface other than the coil installation surface of the stator core or a surface other than the rotor side of the stator core.

  FIG. 6 is an example in which the refrigerant flow path 26a is set in a large area on the back surface, and can be realized by application of a casting technique using a feature of pressure molding such as lost wax. By taking out the flow path inlet / outlet 27 from the back to the case side with the degree of freedom, the flow path inlet / outlet 27 has a good sealing property with the dust core material, and can have a practical flow path configuration without leakage.

  In FIG. 7, in order to correspond to the heat generation point of the stator coil 22, the refrigerant flow path 26 a is set inside the iron core and in the vicinity of the coil 22. The connection of the refrigerant flow path 26a and the like are the same as in FIG.

  FIG. 8 is a diagram illustrating a case where the surface of the iron core is a refrigerant flow path 16a in a stator iron core using a conventional laminated steel plate. In the conventional stator core illustrated in FIG. 8, the coolant channel 16a is formed by machining such as cutting, but the same method can be applied to the present invention. FIG. 9 shows the embodiment, in which a coolant channel 26a is formed by machining in a region corresponding to the channel settable region 26 shown in FIG. Due to the three-dimensional nature of the magnetic flux, the coolant channel 26a can be set deep from the wall surface. Moreover, it is also possible to increase a heat-transfer area by taking a fin shape and to increase a cooling effect. The fin-like refrigerant flow path 26a illustrated in FIG. 9 is characterized in that the refrigerant flow path can be easily realized as compared with the iron core internal flow path. In this embodiment, since a refrigerant flow path is formed between the motor cases 18 and 28, it is necessary to add a liquid refrigerant leakage prevention mechanism such as an O-ring.

  FIG. 10 shows an example of refrigerant flow path formation on the iron core surface utilizing the characteristics of the dust core material. The flow path length (area) corresponding to the heat load is set on the coil opposite surface. It is preferable that the refrigerant inlet / outlet part 27 is also set on the opposite side of the coil.

  The present invention can be applied regardless of how the stator coil is wound. That is, the refrigerant flow path 26a can be set regardless of the difference between concentrated winding and distributed winding. Further, the present invention can be applied to either a single pole or a multipole assembly regardless of the pole splitting method of the iron core.

  Next, this embodiment will be described by showing the overall appearance of a radial motor. FIG. 11 shows the external shape of a stator of a conventional radial type motor, in which an axial internal flow path 46a is provided on the circumferential outer surface side of the teeth (grooves as viewed from the outer surface). There are examples of processing). The refrigerant inlet / outlet 47 in the axial direction has nothing but to press the side plate through a seal, and it is not easy to prevent leakage of the refrigerant. On the other hand, the Example at the time of applying this invention is shown in FIG. From the viewpoint of not affecting the magnetic flux, the outer circumferential surface side of the teeth is an appropriate area as the refrigerant flow path 56a, and the flow path setting there is the same as in the prior art. However, since the iron core is made of a powder magnetic core material, a flow path setting to the additional area 52a can be made as the flow path turning portion 56b by providing the hook-shaped additional area 52a with the axial end face extended. Therefore, it is possible to configure the series flow path having a large cooling capacity without affecting the magnetic flux. Moreover, since the refrigerant inlet / outlet part can be set on the outer surface, it is possible to easily provide the refrigerant flow path 56a without leakage, which was difficult in the prior art.

  The above description will be shown collectively in FIG. 13. When the iron core is formed of a dust core material, the refrigerant flow path configuration has a three-dimensional arbitrary magnetic flux possible direction in the iron core. ) It is possible to expand the iron core to an area where the influence of magnetic flux is small and to form a flow path there. (2) The conventional laminated steel plate has a strong influence of the magnetic flux, and even if the flow path is difficult to form, By changing the direction to another direction, it is possible to set the refrigerant flow path for the area where the influence of the magnetic flux is weak. (3) By expanding the iron core to the area where the influence of the magnetic flux is small and guiding the magnetic flux there It is possible to obtain an effect not in the prior art that the thickness of the stator yoke can be reduced and the motor can be miniaturized.

Any liquid refrigerant introduced into the refrigerant flow path may be used as long as it can be a cooling working fluid such as oil, water, freon, fluorinate, and CO ₂ . Furthermore, it is preferable to form an organic or inorganic corrosion-resistant film on the surface of the coolant channel in order to extend the life of the dust core material constituting the coolant channel.

It is a figure which shows the structure of the conventional radial type motor, (a) is the cross-sectional schematic of the axial direction of a radial type motor, (b) is the cross-sectional schematic of the radial direction of a radial type motor. It is a figure which shows a part of stator core of the radial type motor comprised with the laminated steel plate. It is a figure which shows a part of stator core at the time of applying this invention to the stator core of a radial type motor. It is a figure which shows the structure of the radial type motor in this embodiment, (a) is the cross-sectional schematic of the axial direction of a radial type motor, (b) is the cross-sectional schematic of the radial direction of a radial type motor. It is the figure which looked at the flow-path setting possible area | region of the stator core shown in FIG. 3 from the side surface. It is a figure which shows the structural example of the concrete refrigerant | coolant flow path formed in the stator core in this embodiment. It is a figure which shows the structural example of the concrete refrigerant | coolant flow path formed in the stator core in this embodiment. It is a figure which illustrates the case where the iron core surface is used as a refrigerant channel in the conventional stator iron core using laminated steel plates. In the stator iron core of this embodiment, it is a figure which illustrates the case where the iron core surface is used as a refrigerant flow path. It is a figure which shows the example of refrigerant | coolant flow path formation to the iron core surface using the characteristic of a powder magnetic core material. It is a figure which shows the external appearance shape of the stator of the conventional radial type motor. It is a figure which shows the Example at the time of applying this invention to the stator of a radial type motor. It is a figure for demonstrating the whole outline | summary of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Rotor, 11, 23 Stator iron core, 11a teeth, 11b Back yoke, 12, 22 Stator coil, 13 Stator, 15, 25 Magnetic flux line, 16, 26, 56a Refrigerant flow path installation area | region, 18, 28 Motor case, 23a, 52a additional region, 16a, 26a Refrigerant flow path, 27, 47 Refrigerant inlet / outlet part, 46a Internal flow path, 56b Flow path turning part.

Claims (4)

A rotor which is a field magnetic flux generation source;
A stator composed of a plurality of sets of stator coils wound around a plurality of stator cores that generate a rotating magnetic field for rotating the rotor;
In a radial type rotating electric machine including
The stator core is
A plurality of teeth around which a stator coil is wound;
A back yoke disposed on one end side of the tooth, the back yoke having a flange protruding from the end surface of the tooth in the axial direction of the stator core;
With
The plurality of teeth and the back yoke are formed of a dust core material,
The back yoke is provided with a refrigerant flow path therein,
The refrigerant flow path includes an axial portion extending in the axial direction of the stator core along the center of the back surface of the teeth, and a turning portion provided in the flange portion that connects the axial direction portions adjacent to each other in the circumferential direction. Having
Rotating electric machine characterized by that. 2. The rotating electrical machine according to claim 1, wherein the stator iron core is integrally formed of a powder magnetic material, and the refrigerant flow path is formed over the integrally formed stator iron core. Rotating electric machine. 3. The rotating electrical machine according to claim 1, wherein an inlet / outlet portion of the refrigerant flow path is provided on a surface other than the coil installation surface of the stator core or a surface other than the rotor side of the stator core. A rotating electric machine characterized by The rotating electrical machine according to any one of claims 1 to 3, wherein a corrosion-resistant film is formed on a wall surface of the refrigerant flow path.

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