JP2021191034A - Rotary electric machine rotor - Google Patents

Abstract

To provide a rotary electric machine rotor having a cooling structure capable of improving cooling efficiency by directly cooling a magnet with cooling oil.SOLUTION: A rotary electric machine rotor 10 according to the present invention includes: a rotor core 12 composed of a laminated steel plate 14 having a magnet hole 17; a magnet 13 inserted into the magnet hole 17 and fixed to the magnet hole 17 by a magnet fixing material 18; and a refrigerant passage 16 formed in the rotor core 12. Further, the magnet hole 17 communicates with the refrigerant passage 16, and an outer wall of the magnet 13 forms a part of the refrigerant passage 16. Furthermore, at least a part of the outer wall of the magnet 13 forming the refrigerant passage 16 is not covered with the magnet fixing material 18.SELECTED DRAWING: Figure 1

Description

The present invention relates to a rotary electric rotor.

In a rotary electric machine, the magnet generates heat due to the magnet eddy current caused by the high-speed rotation of the rotor. Therefore, there is a problem that the magnet is thermally demagnetized and the torque is reduced. As a method of cooling the magnet, there is a method of injecting cooling oil from the axis to cool the magnet. Patent Document 1 discloses a technique for cooling a magnet by passing cooling oil through a porous body.

Japanese Unexamined Patent Publication No. 2019-9866

In Patent Document 1, a cooling oil passage is provided in the porous body from the rotor core to cool the magnet. At this time, the pressure loss in the porous body is large, and it is difficult to secure the amount of oil required for heat exchange. Further, since it is not a method of bringing the cooling oil into direct contact with the magnet, it can be said that the magnet is indirectly cooled. Therefore, there is a problem that the cooling efficiency of the magnet is not high.

An object of the present invention is to provide a rotary electric rotor having a cooling structure capable of improving cooling efficiency.

The rotary electric rotor according to the present invention is formed in the rotor core, a rotor core made of a laminated steel plate having magnet holes, a magnet inserted into the magnet holes and fixed to the magnet holes by a magnet fixing material, and a magnet. The magnet hole communicates with the refrigerant path, the outer wall of the magnet forms a part of the refrigerant path, and at least a part of the outer wall of the magnet forming the refrigerant path. Is not covered with the magnet fixing material. Due to the structure of the rotary electric machine rotor, the magnet is directly cooled by the cooling oil, so that the cooling efficiency of the magnet can be improved.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a rotary electric rotor having a cooling structure capable of improving cooling efficiency.

It is a vertical sectional view of the rotary electric machine which concerns on Embodiment 1 of this invention. It is a top view which partially shows the structure of the rotary electric rotor which concerns on Embodiment 1 of this invention. It is a perspective view which shows the structure of the rotary electric machine rotor which concerns on Embodiment 1 of this invention partially. It is a top view which partially shows the structure of the rotary electric rotor which concerns on a comparative example. It is a perspective view which shows the structure of the rotary electric machine rotor which concerns on a comparative example partially. It is the schematic of the vertical cross section which shows the flow of the cooling oil in the rotary electric rotor which concerns on the modification of this invention.

Hereinafter, embodiments will be described with reference to the drawings. Since the drawings are simple, the technical scope of the embodiment should not be narrowly interpreted based on the description of the drawings. Further, the same elements are designated by the same reference numerals, and duplicate description will be omitted. Further, in the following embodiments, when the number of elements (including the number, numerical value, quantity, range, etc.) is referred to, when it is specified in particular, or when it is clearly limited to a specific number in principle, etc. Except for this, the number is not limited to the specific number, and may be more than or less than the specific number.

Further, in the following embodiments, the components are not necessarily essential except when explicitly stated and when it is clearly considered to be essential in principle. Similarly, in the following embodiments, when the shape, positional relationship, etc. of the constituent elements, etc. are referred to, the shape, etc. It shall include those similar to or similar to. This also applies to the above numbers and the like (including the number, numerical value, quantity, range and the like).

Hereinafter, for the sake of clarification of the explanation, the explanation will be given using the xyz3D Cartesian coordinate system. The z-direction is the thickness direction of the rotor, which is the laminating direction of the laminated steel sheets. The xy plane is a plane parallel to the main surface of the rotor and the laminated steel plate. Further, although the description will be made assuming that the + z direction is the upward direction, it changes depending on the direction in which the rotary electric machine is arranged.

<Embodiment 1>
The rotary electric rotor 10 according to the present embodiment will be described with reference to FIGS. 1, 2, and 3. FIG. 1 is a vertical cross-sectional view of a rotary electric machine 1 using the rotary electric machine rotor 10 according to the present embodiment. FIG. 2 is a plan view partially showing the structure of the rotary electric motor rotor 10 according to the present embodiment. Further, FIG. 3 is a perspective view partially showing the structure of the rotary electric rotor 10 according to the present embodiment.

The rotary electric machine 1 shown in FIG. 1 is composed of a rotary electric machine rotor 10 and a stator 20 according to the present embodiment. The rotary electric machine rotor 10 has a rotor shaft 11, a rotor core 12, and a magnet 13. Further, the stator 20 has a stator core 21 and a coil 22. The rotor core 12 is composed of a laminated steel plate 14.

As shown in FIG. 1, the rotor shaft 11 is a pipe-shaped member extending in the + z direction, and is fitted into a shaft hole 15 provided in the rotor core 12. A refrigerant passage 16 is provided inside the rotor shaft 11. The rotary electric rotor 10 can be cooled by flowing the refrigerant through the refrigerant passage 16. Refrigerants include, for example, cooling oil, cooling water and air. Although it is described in the present specification that the cooling oil is used as the refrigerant, the present invention is not limited to this. The rotor shaft 11 is not limited to the pipe-shaped member, but may be a rod-shaped member.

As shown in FIG. 1, the rotor core 12 is formed by laminating a laminated steel plate 14 punched in an annular shape in the upward direction (+ z direction). The plurality of laminated steel plates 14 constituting the rotor core 12 are integrally connected by adhesion, welding, or the like. In order to reduce the energy loss due to the eddy current generated in the rotor core 12 as much as possible, the laminated steel plates 14 constituting the rotor core 12 may be electrically insulated from each other by insulating films formed on the surfaces on both sides.

The magnet 13 is inserted into the magnet hole 17 extending in the circumferential direction at the outer edge of the laminated steel plate 14, and is sealed by the magnet fixing material 18. The region where the magnet fixing material 18 covers the magnet 13 is a region where the magnet 13 and the cooling oil do not come into contact with each other. In the example shown in FIG. 2, two long side surfaces and one short side surface of the magnet 13 other than the short side surface 13a are covered with the magnet fixing material 18. On the other hand, the short side surface 13a of the magnet 13 forming the refrigerant passage 16 is not covered with the magnet fixing material 18. As the magnet fixing material 18, for example, a foamed resin such as epoxy (that is, a porous body) is used, but the magnet fixing material 18 is not limited to this. The magnet 13 may be coated with, for example, an epoxy coat to prevent deterioration due to cooling oil.

Here, a rotating magnetic field is generated by the current flowing through the coil 22, and the rotary electric machine rotor 10 rotates due to the electromagnetic action acting between the rotating magnetic field and the rotor core 12. The rotary electric machine 1 generates heat due to the current flowing through the coil 22 of the stator core 21 during rotation. In particular, when the rotary electric machine rotor 10 is rotated at high speed or when the rotary electric machine 1 is large, the amount of heat generated by the rotor core 12 during rotation becomes significantly large. Therefore, the temperature of the magnet 13 rises remarkably. When the temperature of the magnet 13 rises remarkably, the magnetic flux that generates torque decreases, so that the performance of the rotary electric machine 1 deteriorates. Therefore, it is necessary to cool the magnet 13 when the rotary electric machine 1 rotates.

In the rotor core 12, the cooling oil flows into the refrigerant passage 16 from the axial direction (−x direction) of the rotor shaft 11, passes through the outer wall of the magnet 13, and is discharged from the vertical direction (+ z direction and −z direction) of the rotor core 12. Will be done. This process cools the magnet 13.

In the present embodiment, the outer wall of the magnet 13 forms a part of the refrigerant passage 16. More specifically, as shown in FIG. 2, the short side surface 13a and the long side surface portion 13b of the magnet 13 form a part of the refrigerant passage 16. Here, the short side surface 13a of the magnet 13 forming the refrigerant passage 16 is not covered with the magnet fixing material 18. That is, it has a region where the cooling oil comes into direct contact with the magnet 13. Therefore, the magnet 13 is directly cooled by the cooling oil. Therefore, the cooling efficiency of the magnet 13 can be improved as compared with the cases of FIGS. 4 and 5. In the present invention, the magnet 13 may be in direct contact with the flow path of the cooling oil. Therefore, the form of forming the refrigerant path by the outer wall of the magnet 13 does not matter.

It is sufficient that at least a part of the outer wall of the magnet 13 forming the refrigerant passage 16 is not covered with the magnet fixing material 18. On the other hand, in the example shown in FIG. 2, a part 13b of the long side surface of the magnet 13 forming the refrigerant passage 16 is covered with the magnet fixing material 18, but a part 13b of the long side surface is covered with the magnet fixing material 18. It does not have to be.

Here, when the magnet 13 has a lower temperature than the rotor core 12 in the cooling process, a heat flow from the rotor core 12 to the magnet 13 may be generated. At this time, the cooling efficiency of the magnet 13 deteriorates.

Further, from the viewpoint of preventing the heat flow from the rotor core 12 to the magnet 13 described above, the magnet fixing material 18 is made of a material having a heat insulating property having low thermal conductivity. A thermosetting resin is used as the material of the magnet fixing material 18, but the material is not limited to this. Further, the magnet fixing material 18 may be used together as an insulating film of the rotor core 12.

<Comparison example>
Here, the problems of the rotary electric rotor according to the comparative example will be described with reference to FIGS. 4 and 5. FIG. 4 is a plan view partially showing the structure of the rotary electric rotor according to the comparative example. Further, FIG. 5 is a perspective view partially showing the structure of the rotary electric rotor according to the comparative example.

In FIGS. 4 and 5, the cooling oil flows into the refrigerant passage 16 from the axial direction (−x direction) of the rotary electric machine 1 as in the case of FIGS. 2 and 3. Then, it is discharged from the vertical direction (+ z direction and −z direction) of the rotor core 12. As shown in FIGS. 4 and 5, the magnet hole 17 does not communicate with the refrigerant passage 16 and the cooling oil does not come into direct contact with the magnet 13, so that the magnet 13 is indirectly cooled.

Here, the magnet 13 is fixed to the magnet hole 17 by the magnet fixing material 18. As shown in FIG. 4, the gap between the magnet 13 and the magnet hole 17 is filled with the magnet fixing material 18. That is, the entire outer wall (short side surface and long side surface) of the magnet 13 is covered with the magnet fixing material 18.

On the other hand, in the rotary electric machine rotor 10 according to the present embodiment, the magnet hole 17 communicates with the refrigerant passage 16, and the outer wall of the magnet 13 forms a part of the refrigerant passage 16. At least a part of the outer wall of the magnet 13 forming the refrigerant passage 16 is not covered with the magnet fixing material 18. Therefore, the magnet 13 can be directly cooled by the cooling oil, and the cooling efficiency of the magnet 13 can be improved.

<Modification example>
FIG. 6 is a schematic view of a vertical cross section showing the flow of cooling oil in a part of the rotary electric machine 1 according to the modified example of the present invention. In FIG. 6, in order to show the flow of cooling oil, the illustration of components (magnet 13, magnet hole 17, and magnet fixing material 18) other than the rotor core 12, the laminated steel plate 14, and the end plate 30 is omitted. In FIG. 6, end plates 30 are provided above and below (± z direction) the laminated steel plate 14 constituting the rotor core 12. The arrow shown in FIG. 6 represents the flow of cooling oil. In FIG. 6, a structure for injecting cooling oil from the spindle direction (−x direction) will be described.

As shown in FIG. 6, a gap is provided in a part between the laminated steel plate 14 and the end plate 30 on the upper surface (+ z direction). Similarly, a gap is provided between the lower surface (−z direction) and the laminated steel plate 14. Further, a hole in the vertical direction (± z direction) is provided in a part of the laminated steel plate 14 so as to connect the gap provided on the upper surface and the gap provided on the lower surface. In FIG. 6, the hole is vertical when viewed from the end plate 30, but the hole is not limited to this.

At this time, the cooling oil flows into the gap between the upper surface side (+ z direction side) end plate 30 and the laminated steel plate 14 from the spindle direction (−x direction). The holes provided in the laminated steel plate 14 flow downward (−z direction), and flow through the gap between the laminated steel plate 14 and the end plate 30 on the lower surface side (−z direction side) in the direction opposite to the main axis (+ x direction).

In this way, the refrigerant passage 16 is not formed only in the hole portion of the laminated steel plate 14 as in the first embodiment, but a part of the refrigerant passage is formed in the laminated steel plate 14 and the end plate 30 as in the present modification. It can also be formed as a gap. Also in this modification, the same cooling effect as that of the first embodiment is obtained.

Although the present invention has been described above in accordance with the above-described embodiment, the present invention is not limited to the configuration of the above-described embodiment, and is within the scope of the claimed invention within the scope of the claims of the present application. Of course, it includes various modifications, corrections, and combinations that can be made by a person skilled in the art.

10 Rotating electric machine rotor 12 Rotor core 13 Magnet 14 Laminated steel plate 15 Shaft hole 16 Refrigerant path 17 Magnet hole 18 Magnet fixing material

Claims (1)

A rotor core made of laminated steel plate with magnet holes and
A magnet inserted into the magnet hole and fixed to the magnet hole by a magnet fixing material,
The refrigerant passage formed in the rotor core and
Equipped with
The magnet hole communicates with the refrigerant passage, and the outer wall of the magnet forms a part of the refrigerant passage.
At least a part of the outer wall of the magnet forming the refrigerant passage is not covered with the magnet fixing material.
Rotating electric rotor.

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