Rotating electric machine

Abstract

This rotary electric machine comprises: a rotor core that has a plurality of magnet holes; and a plurality of magnets that are inserted into the magnet holes, respectively. The magnets include: a pair of first layered magnets that are arranged in a V shape; and a pair of second layered magnets that are arranged in a V shape more on the inner diameter side than the first layered magnets. The rotor core has a hole at a position which is between the first layered magnets and the second layered magnets and which overlaps a d-axis which is the magnetic pole center of the rotor core.

Description

Technical Field

[0001] The present invention relates to a rotating electrical machine.

Background Art

[0002] In a rotating electrical machine, the stress in the rotor core generated by the centrifugal force of the rotor varies depending on the shape of the magnet holes in the rotor core. From the perspective of reliability, the maximum principal stress needs to be less than or equal to the material strength of the rotor core material. Also, the torque of the rotor is improved with a magnet configuration arranged in a double V shape rather than a single V shape. Therefore, adopting the latter is advantageous for performance improvement, but the stress in the rotor core becomes larger. Based on this, the rotor core is required to achieve both torque improvement and stress resistance.

[0003] In Patent Document 1 below, a configuration of a permanent magnet motor with a double V-shaped magnet arrangement and holes provided not only in the magnet insertion portion but also elsewhere to disperse the stress in the rotor core generated by centrifugal force is disclosed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the configuration described in Patent Document 1, since there are large holes in the d-axis portion between the second layers, the magnet flux cannot be effectively used, and the adverse effect on the performance of the motor is significant. Also, while the performance of the motor deteriorates, there are also problems with the strength due to the stress in the rotor core caused by the centrifugal force during rotation. In view of this, an object of the present invention is to provide a rotating electrical machine that reduces stress without reducing torque and improves rotational strength.

Means for Solving the Problems

[0006] A rotating electric machine comprising a rotor core having a plurality of magnet holes, and a plurality of magnets inserted into each of the magnet holes, wherein the magnets include a pair of first layer magnets arranged in a V shape, and a pair of second layer magnets arranged in a V shape on the inner diameter side of the first layer magnets, and the rotor core has a hole between the first layer magnets and the second layer magnets, at a position that coincides with the d-axis, which is the magnetic pole center of the rotor core. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a rotating electric machine that reduces stress and improves rotational strength without reducing torque. [Brief explanation of the drawing]

[0008] [Figure 1] Overall diagram of a rotating electric machine [Figure 2] An explanatory diagram of the hole portion of the rotor of a rotating electric machine according to one embodiment of the present invention. [Figure 3] Figure 2 is an explanatory diagram of the area defining the position of the hole. [Figure 4] First variation [Figure 5] Second variation [Figure 6] Diagram illustrating the definition of the hole in Figure 2. [Figure 7] Diagram illustrating the relationship between the d-axis and the magnetic hole.

[0009] Embodiments of the present invention will be described below with reference to the drawings. The following description and drawings are illustrative for illustrating the present invention, and have been omitted and simplified as appropriate for clarity of explanation. The present invention can also be carried out in various other forms. Unless otherwise specified, each component may be singular or plural.

[0010] The positions, sizes, shapes, and ranges of the components shown in the drawings may not represent their actual positions, sizes, shapes, and ranges in order to facilitate understanding of the invention. Therefore, the present invention is not necessarily limited to the positions, sizes, shapes, and ranges disclosed in the drawings.

[0011] (One embodiment of the present invention and its overall configuration) (Figure 1) Figure 1(a) is a view of the rotating electric machine from the axial direction. Figure 1(b) is a view of Figure 1(a) from the radial direction. The rotating electric machine 1 is equipped with a stator 2 on the outer circumference and a rotor 3 on the inner circumference. The rotor 3 faces the stator 2 with a predetermined air gap (not shown) in between. The stator core 2a is an electrical steel sheet having a plurality of slots. A plurality of coils 6 are inserted into the plurality of slots provided in the stator core 2a, arranged radially.

[0012] (Figure 2) The rotor core 4 (hereinafter referred to as core 4) of the rotor 3 has a plurality of holes. Of these plurality of holes, the magnet holes into which the plurality of magnets are inserted include magnet holes into which a pair of first layer magnets 11 arranged in a V shape are inserted, and magnet holes into which a pair of second layer magnets 12 arranged in a V shape on the inner diameter side of the first layer magnets 11 are inserted.

[0013] Core 4 has a hole 10 located between the first layer magnet 11 and the second layer magnet 12, at a position that coincides with the d-axis 7, which is the magnetic pole center of the rotor core 4. This hole 10 is a stress-reducing hole located in a position that does not affect the magnetic performance, as it is not located in a part of the core 4 where the magnetic flux density is high, i.e., on the path of the magnetic flux.

[0014] (Figure 3) The hole portion 10 is disposed in a region 8 formed by connecting the corner portion on the innermost diameter side among the corner portions of the first layer magnet 11 and the corner portion closest to the d-axis 7 among the corner portions of the second layer magnet 12, respectively. By providing the hole portion 10 in the region 8, at a position overlapping the d-axis 7 and between the first layer magnet hole and the second layer magnet hole, the burden of the stress related to the d-axis 7 can be evenly distributed and reduced between the inside and the outside of the core 4. Therefore, stress reduction and rotation strength improvement of the core 4 can be achieved.

[0015] Note that as long as the hole portion 10 is provided between the first layer magnet 11 and the second layer magnet 12 and at a position overlapping the d-axis 7, and the hole portion 10 is formed by a void, a plurality of hole portions 10 may be formed in the core 4.

[0016] (First Modified Example) (Fig. 4) The hole portion 10a includes a lower side having a predetermined curvature and convex toward the inner side in the radial direction, and an upper side having a curvature smaller than the predetermined curvature and convex toward the outer side in the radial direction. By adopting the hole portion 10a with different curvatures on the outer and inner sides in the radial direction, the load can be evenly distributed without affecting the magnetic performance, and further stress reduction and rotation strength improvement of the core 4 can be achieved.

[0017] (Second Modified Example) (Fig. 5) The hole portion 10b includes a lower side having a predetermined curvature and convex toward the inner side in the radial direction, and an upper side having a curvature larger than the predetermined curvature and convex toward the outer side in the radial direction. By adopting the hole portion 10b with different curvatures on the outer and inner sides in the radial direction, the load can be evenly distributed without affecting the magnetic performance, and further stress reduction and rotation strength improvement of the core 4 can be achieved.

[0018] Note that the hole 10 described in FIGS. 2 and 3 and the holes 10a and 10b described in FIGS. 4 and 5 have the same area. Also, the hole 10 may be provided at a location on the core 4 that does not affect the magnetic flux path even if it has a shape other than the holes 10a and 10b of the modified examples shown above, and its size may not be limited as long as it does not affect the magnetic flux path.

[0019] (FIG. 6) The maximum diameter dimension d1 of the hole 10 is larger than the bridge width d2 formed between a pair of magnet holes into which the second layer magnets 12 are respectively inserted. In FIG. 6, for the sake of easy understanding of the comparison of the width dimensions, the maximum diameter dimension d1 is shown in the direction orthogonal to the d-axis 7. Thereby, the load supported by the bridge portion crossing the d-axis 7 is reduced and it becomes difficult to deform, so that the stress generated inside the core 4 in the radial direction can be more evenly dispersed to the outside in the radial direction.

[0020] (FIG. 7) The first angle θ1 formed by the first layer magnet 11 and the d-axis 7 is larger than the second angle θ2 formed by the second layer magnet 12 and the d-axis 7. With such a configuration, the stress reduction effect of the core 4 due to the hole 10 provided between the first layer magnet 11 and the second layer magnet 12 becomes greater.

[0021] As described above, the hole 10 of the present invention has been described. However, since the first layer magnet 11 and the second layer magnet 12 generate heat simultaneously with the rotation of the core 4, a configuration may be adopted in which cooling water is caused to flow through this hole 10 to promote cooling.

[0022] According to one embodiment of the present invention described above, the following operational effects are achieved.

[0023] (1) A rotating electric machine 1 comprising a rotor core 4 having a plurality of magnet holes and a plurality of magnets inserted into each of the magnet holes, wherein the magnets include a pair of first layer magnets 11 arranged in a V shape and a pair of second layer magnets 12 arranged in a V shape on the inner diameter side of the first layer magnets 11. The rotor core 4 has a hole portion 10 between the first layer magnets 11 and the second layer magnets 12, at a position that coincides with the d-axis 7, which is the magnetic pole center of the rotor core 4. In this way, a rotating electric machine 1 can be provided that reduces stress without reducing torque and improves rotational strength.

[0024] (2) The hole 10 is located within the region 8 formed by connecting the innermost corner of the first layer magnet 11 and the corner of the second layer magnet 12 closest to the d7 axis. This arrangement reduces stress on the core 4 and improves rotational strength.

[0025] (3) The hole 10a comprises a lower side having a predetermined curvature and convex radially inward, and an upper side having a curvature smaller than the predetermined curvature and convex radially outward. This further reduces stress on the core 4 and improves rotational strength.

[0026] (4) The hole 10b comprises a lower side having a predetermined curvature and convex radially inward, and an upper side having a curvature greater than the predetermined curvature and convex radially outward. This further reduces stress on the core 4 and improves rotational strength.

[0027] (5) The rotor core 4 has at least one hole 10 located between the first layer magnet 11 and the second layer magnet 12 and overlapping with the d-axis 7. This hole 10 is formed by at least one void. This further reduces stress on the core 4 and improves rotational strength.

[0028] (6) The maximum diameter dimension d1 of the hole 10 is greater than the bridge width d2 formed between the pair of magnet holes into which the second layer magnets 12 are inserted. This allows the stress of the core 4 to be evenly distributed radially outward.

[0029] (7) The first angle θ1 formed by the first layer magnet 11 and the d-axis 7 is greater than the second angle θ2 formed by the second layer magnet 12 and the d-axis 7. This increases the stress reduction effect of the core 4.

[0030] It should be noted that the present invention is not limited to the embodiments described above, and various modifications and combinations of other configurations can be made without departing from the spirit of the invention. Furthermore, the present invention is not limited to having all the configurations described in the embodiments described above, and may also include configurations in which some of those configurations are omitted. [Explanation of Symbols]

[0031] 1. Rotating electric machine 2 Stator 3 rotors 4 rotor cores 5 slots 6 coils 7 d axis 8 areas 10 Hole 10a Hole in the first modified example 10b Hole in the second modified example 11. First Layer Magnet 12. Second layer magnet d1 Maximum diameter of the hole d2 bridge width

Claims

1. A rotating electric machine comprising a rotor core having multiple magnet holes, and multiple magnets inserted into each of the magnet holes, The magnet includes a pair of first layer magnets arranged in a V-shape, and a pair of second layer magnets arranged in a V-shape on the inner diameter side of the first layer magnets. The rotor core has a hole located between the first layer magnet and the second layer magnet, at a position that coincides with the d-axis, which is the magnetic pole center of the rotor core. The aforementioned hole is located within a region formed by connecting the corner of the first layer magnet that is closest to the inner diameter and the corner of the second layer magnet that is closest to the d-axis, and comprises a lower side having a predetermined curvature and convex radially inward, and an upper side having a curvature smaller than the predetermined curvature and convex radially outward. Rotating electric machine.

2. A rotating electric machine according to claim 1, The rotor core has at least one of the holes located between the first layer magnet and the second layer magnet, and overlapping with the d-axis. The aforementioned hole is formed by at least one void. Rotating electric machine.

3. A rotating electric machine according to claim 2, The maximum diameter of the aforementioned hole is greater than the bridge width formed between the pair of magnet holes into which the second layer magnets are inserted. Rotating electric machine.

4. A rotating electric machine according to claim 2, The first angle formed by the first layer magnet and the d-axis is greater than the second angle formed by the second layer magnet and the d-axis. Rotating electric machine.

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