Rotor of rotating electrical machine

Abstract

This rotor for a rotary electric machine comprises a pair of magnets arranged in a V-shape, and a rotor core having formed therein magnet holes through which the magnets are inserted. The rotor core includes, on the radially outside thereof, a protrusion part that has a magnetic gap with respect to an outermost diameter corner portion located on the radially outermost side among corner portions of the magnets, and that is formed so as to be protruded to the magnets, between a first outermost diameter part closer to the magnetic pole center of the rotor than the outermost corner portion is, on the outer diameter of the magnetic gap, and a second outermost diameter part closer to the magnetic pole boundary of the rotor than the outermost diameter corner portion is, on the outermost diameter of the magnetic gap. The protrusion part is opposite to main surfaces of the magnets.

Description

[Technical field]

[0001] The present invention relates to a rotor for a rotating electric machine. [Background technology]

[0002] As background art to the present invention, for example, Patent Document 1 listed below discloses a configuration in which multiple holes are formed for the purpose of positioning magnets, and a flux barrier, a side bridge, and first and second recesses are provided that are recessed inwardly from both circumferential ends of the side bridge into the rotor core, thereby improving durability while maintaining good characteristics as an electric motor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2014-197971 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above configuration, it is not possible to increase the maximum torque and reduce the stress at the same time. In view of this, an object of the present invention is to provide a rotor for a rotating electric machine that achieves both an increase in the maximum torque and a reduction in the stress, and further reduces the torque ripple. [Means for solving the problem]

[0005] A rotor for a rotating electric machine comprising a pair of magnets arranged in a V-shape and a rotor core in which magnet holes are formed into which the magnets are inserted, wherein the rotor core has a magnetic gap on the radial outside between itself and an outermost corner portion that is located radially outward among the corners of the magnets, and has a protrusion formed to protrude toward the magnet between a first outermost portion at the outer diameter of the magnetic gap that is closer to the magnetic pole center of the rotor than the outermost corner portion and a second outermost portion at the outer diameter of the magnetic gap that is closer to the magnetic pole boundary of the rotor than the outermost corner portion, and the protrusion faces the main surface of the magnet. Effect of the Invention

[0006] It is possible to provide a rotor for a rotating electrical machine which achieves both an increase in maximum torque and a reduction in stress, and further reduces torque ripple. [Brief description of the drawings]

[0007] [Figure 1] Cross-sectional view of a rotating electrical machine [Diagram 2] FIG. 2 is an enlarged view of a portion of a rotor core according to an embodiment of the present invention; [Diagram 3] Some examples of rotor cores of the prior art [Figure 4] Graph showing the effect of one embodiment of the present invention [Diagram 5] FIG. 1 is a diagram of the distance between the outer periphery and the magnetic air gap according to an embodiment of the present invention.

[0008] (One embodiment of the present invention and overall configuration) Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The following description and drawings are examples for explaining the present invention, and appropriate omissions and simplifications have been made for clarity of explanation. The present invention can be implemented in various other forms. Unless otherwise specified, each component may be singular or plural.

[0009] In order to facilitate understanding of the invention, the position, size, shape, range, etc. of each component shown in the drawings may not represent the actual position, size, shape, range, etc. Therefore, the present invention is not necessarily limited to the position, size, shape, range, etc. disclosed in the drawings.

[0010] (Figure 1) The rotating electric machine 100 has a stator 1 and a rotor 2. The rotor 2 faces the stator 1 via a predetermined air gap. The rotating electric machine 100 is, for example, a permanent magnet type rotating electric machine used for driving a vehicle.

[0011] (Figs. 2 and 3) The rotor 2 includes a pair of magnets 5 arranged in a V-shape, and a rotor core 2a in which a magnet hole 5a into which the magnet 5 is inserted is formed. When the magnet 5 is inserted into the magnet hole 5a, a magnetic air gap 9 is formed on the radially outer side. The magnetic air gap 9 is a gap for reducing leakage flux of the magnet 5, and is provided between the outermost diameter part of the rotor core 2a and an outermost diameter corner 5b that is located radially outermost among the corners that the magnet 5 has.

[0012] In the outermost diameter portion of the magnetic air gap 9, a portion close to the magnetic pole center 4 of the rotor 2 is defined as a first outermost diameter portion 9a. In addition, in the outermost diameter portion of the magnetic air gap 9, a portion close to the magnetic pole boundary 3 of the rotor 2 is defined as a second outermost diameter portion 9b.

[0013] Although not shown in Fig. 2, the rotor core 2a has another magnet 5 formed on either side of the magnetic pole center 4, and this pair of magnets 5 forms one magnetic pole. Furthermore, the rotor core 2a has N poles and S poles arranged alternately. The magnetic pole center 4 and magnetic pole boundary 3 are respectively the d-axis, which is the center of the parts that become the N pole and S pole and is the direction of the magnetic flux created by the magnetic poles, and the q-axis, which is the boundary between the parts that become the N pole and S pole and is electrically and magnetically perpendicular to the d-axis.

[0014] A protrusion 8 is provided on the edge between the first outermost diameter portion 9a and the second outermost diameter portion 9b so as to protrude radially inward (toward the central axis of the rotor core 2a) and toward the magnet 5. This protrusion 8 faces a main surface 6 of the magnet 5 across a predetermined gap. The main surface 6 is a surface that becomes the magnetic poles (N pole, S pole) of the rotor 2.

[0015] In the conventional technology shown in Fig. 3, the magnetic air gap 9A provided by the magnet 5A inserted into the magnet hole of the rotor core 2A does not have a structure like the aforementioned protrusion 8. If there was no protrusion 8 as in the conventional technology, the magnetic flux path would be narrower overall, resulting in a high magnetic flux density, which would increase the maximum torque but also increase the torque ripple.

[0016] To solve this problem, in the present invention, the protrusion 8 is provided to partially widen the magnetic flux path in the outermost diameter part of the rotor core 2a, lowering the magnetic flux density and reducing the torque, and the first outermost diameter part 9a and the second outermost diameter part 9b are partially narrowed to increase the torque, thereby controlling the level of magnetic flux density at each rotation position. This increases the maximum torque of the rotating electric machine 100 compared to the conventional shape, and further reduces the torque ripple for each current phase.

[0017] In addition, the predetermined gap between the protrusion 8 and the main surface 6 of the magnet has an effect against stress. If this predetermined gap were filled, the area of ​​the protrusion 8 would increase, making it heavier, and the maximum stress in the part supporting the protrusion 8 would increase. Furthermore, if the support part were made thicker to reduce the stress, the leakage flux would increase and the maximum torque would decrease. Therefore, by providing a predetermined gap between the protrusion 8 and the main surface 6 of the magnet, it is possible to both suppress the increase in the maximum stress and suppress the decrease in the maximum torque.

[0018] In order to improve the fixation of the magnet 5 inserted in the magnet hole 5a, the corner 5c of the magnet 5 that is closest to the magnetic pole boundary 3 is in contact with the rotor core 2a.

[0019] (Figure 4) Figure 4(a) shows the difference in torque ripple between the configuration of the conventional technology (see Figure 3) and the configuration of the present invention (see Figure 2). In the configuration of the conventional technology shown by the dotted line, the degree of torque fluctuation (torque ripple) of the rotating electric machine was large. However, it can be seen that the configuration of the present invention shown by the solid line has reduced torque ripple compared to the conventional technology shown by the dotted line.

[0020] Figure 4(b) compares the change in torque ripple by time order between the configuration of the conventional technology and the configuration of the present invention. In general, in a three-phase AC motor, torque ripple occurs at harmonic components that are multiples of six with respect to the fundamental wave, but with the present invention, the torque ripple at the 12th time order was reduced by 60% compared to the configuration of the conventional technology.

[0021] (Figure 5) 2, the magnetic path (the outermost diameter portion of the magnetic air gap 9) is narrower than that of the protruding portion 8, which increases the magnetic flux density and increases the torque. The first outermost diameter portion 9a and the second outermost diameter portion 9b are formed so that the distance 10 and the distance 11 from the outer circumferential surface of the rotor core 2a to the magnetic air gap 9 are different.

[0022] This is because experimental results showed that if distance 10 and distance 11 are the same, the strength increases and the maximum stress value can be reduced, but the increase in the number of magnetic flux paths increases the leakage flux, resulting in a decrease in maximum torque.By making a difference in the gap portion such that distance 11 < distance 10 as shown in Figure 5, it is possible to achieve both an increase in maximum torque and a reduction in maximum stress.

[0023] According to the embodiment of the present invention described above, the following advantageous effects are obtained.

[0024] (1) The rotor 2 of the rotating electric machine 100 includes a pair of magnets 5 arranged in a V-shape, and a rotor core 2a in which a magnet hole 5a into which the magnet 5 is inserted is formed. The rotor core 2a has a magnetic gap 9 between the outermost corner 5b, which is the corner of the magnet 5 located at the outermost position in the radial direction, on the radial outside, and has a protrusion 8 formed to protrude toward the magnet 5 between a first outermost diameter portion 9a that is closer to the magnetic pole center 4 of the rotor 2 than the outermost diameter corner 5b at the outer diameter of the magnetic gap 9, and a second outermost diameter portion 9b that is closer to the magnetic pole boundary 3 of the rotor 2 than the outermost diameter corner 5b at the outermost diameter of the magnetic gap 9. The protrusion 8 faces the main surface 6 of the magnet 5. In this way, it is possible to provide a rotor 2 of the rotating electric machine 100 that achieves both an increase in maximum torque and a reduction in stress, and further reduces torque ripple.

[0025] (2) The protrusions 8 face the main surfaces 6 of the magnets 5 with a predetermined gap therebetween. This makes it possible to reduce the stress on the rotor 2.

[0026] (3) The distance between the outer peripheral surface of the rotor 2 and the first outermost diameter portion 9a is longer than the distance between the outer peripheral surface of the rotor 2 and the second outermost diameter portion 9b. This makes it possible to simultaneously increase the maximum torque of the rotating electric machine 100 and reduce the maximum value of the stress.

[0027] (4) Of the corners of magnet 5, corner 5c closest to magnetic pole boundary 4 comes into contact with rotor core 2a. This increases the fixation of magnet 5 to rotor core 2a.

[0028] (5) The rotating electric machine 100 includes the rotor 2 according to the embodiment of the present invention and the stator 1 that faces the rotor 2 via a predetermined air gap. This makes it possible to realize the rotating electric machine 100 that achieves both an increase in maximum torque and a reduction in stress, and further reduces torque ripple.

[0029] The present invention is not limited to the above-described embodiment, and various modifications and other configurations can be combined without departing from the spirit of the present invention. Furthermore, the present invention is not limited to those having all of the configurations described in the above-described embodiment, and includes those in which some of the configurations are omitted. [Explanation of symbols]

[0030] 1 Stator 2 Rotors 2a Rotor core 3 magnetic pole boundary 4 Center of magnetic pole 5. Magnets 5a Magnet hole 5b Outermost diameter corner 5c Corner on the magnetic pole boundary side 6. Main surface of magnet 7 Outer surface 8 Protrusion 9. Magnetic gap 9a First outermost diameter part 9b Second outermost diameter part 10 Distance between outer periphery and magnetic gap (first outermost diameter part) 11 Distance between the outer periphery and the magnetic gap (second outermost diameter part) 100 Rotating Electric Machine

Claims

1. A rotor for a rotating electric machine including a pair of magnets arranged in a V-shape and a rotor core having magnet holes into which the magnets are inserted, The rotor core has a magnetic gap between the outermost corner portion of the magnet that is located radially outward, and a protrusion formed to protrude toward the magnet between a first outermost portion that is closer to the magnetic pole center of the rotor than the outermost corner portion at the outer diameter of the magnetic gap, and a second outermost portion that is closer to the magnetic pole boundary of the rotor than the outermost corner portion at the outer diameter of the magnetic gap, The protrusion faces a main surface of the magnet, The distance between the outer circumferential surface of the rotor and the first outermost diameter portion is longer than the distance between the outer circumferential surface of the rotor and the second outermost diameter portion. Rotor of a rotating electric machine.

2. 2. A rotor for a rotating electric machine according to claim 1, The protrusion faces the main surface of the magnet with a predetermined gap therebetween. Rotor of a rotating electric machine.

3. 2. A rotor for a rotating electric machine according to claim 1, Among the corners of the magnet, the corner closest to the magnetic pole boundary comes into contact with the rotor core. Rotor of a rotating electric machine.

4. A rotor for a rotating electric machine according to any one of claims 1 to 3, and a stator facing the rotor with a predetermined air gap therebetween. Rotating electric motor.

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