Rotor of a rotating electric machine, method for manufacturing a rotor of a rotating electric machine

Abstract

This invention provides a rotor for a rotating electric machine that improves the magnetization of magnets and suppresses stress, as well as a method for manufacturing the rotor for a rotating electric machine. [Solution] The rotor of a rotating electric machine comprises a rotor core having a permanent magnet, a magnet embedding hole for embedding the permanent magnet, a through hole located radially inward from the magnet embedding hole and on the center of the magnetic pole, and passing through in the axial direction, and a rotating shaft passing through the rotor core, wherein the through hole has a convex portion that protrudes radially inward from the radially outward inner wall, is located on the center of the magnetic pole, and is formed integrally with the rotor core.

Description

Technical Field

[0001] The present invention relates to a rotor of a rotating electrical machine and a method for manufacturing the rotor of a rotating electrical machine.

Background Art

[0002] Patent Document 1 below discloses a configuration of a rotor of a rotating electrical machine in which a separate component composed of an auxiliary winding and a core member is fixed after being inserted into a rotor core.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In view of the technology described in Patent Document 1, an object of the present invention is to provide a rotor of a rotating electrical machine and a method for manufacturing the rotor of a rotating electrical machine that achieve improved magnetism attachment and stress suppression of a magnet.

Means for Solving the Problems

[0005] The rotor of the rotating electrical machine includes a permanent magnet, a magnet embedding hole for embedding the permanent magnet, a rotor core that is radially inside the magnet embedding hole and provided on the magnetic pole center and has a through hole penetrating in the axial direction, and a rotating shaft penetrating the rotor core. The through hole has a convex portion that protrudes from the inner wall on the radially outer side toward the radially inner side and is located on the magnetic pole center and is integrally formed with the rotor core.

Effects of the Invention

[0006] It is possible to provide a rotor of a rotating electrical machine and a method for manufacturing the rotor of a rotating electrical machine that achieve improved magnetism attachment and stress suppression of a magnet.

Brief Description of the Drawings

[0007] [Figure 1] An overall perspective view showing the configuration of a rotating electric machine. [Figure 2] A diagram illustrating the configuration of the rotor of a rotating electric machine according to one embodiment of the present invention. [Figure 3] A diagram illustrating the configuration of the rotor of a rotating electric machine according to the manufacturing method of the present invention. [Figure 4] A diagram illustrating the configuration of the through-hole in the rotor of a rotating electric machine according to one embodiment of the present invention. [Figure 5] A diagram illustrating the configuration of the rotor of a rotating electric machine according to a first modified example of the present invention. [Figure 6] A diagram illustrating the configuration of the rotor of a rotating electric machine according to a second modified example of the present invention. [Figure 7] A diagram illustrating the configuration of a rotor for a rotating electric machine, according to a modified example of the manufacturing method of the present invention. [Modes for carrying out the invention]

[0008] 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.

[0009] 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.

[0010] (One embodiment and overall configuration) (Figure 1) The rotating electric machine 1 consists of a stator 100 and a rotor 101. The stator 100 is made up of stacked disc-shaped steel plates formed into any shape, with a rotating shaft 102 at its center. The rotor 101 is made up of stacked disc-shaped steel plates formed into any shape, with a rotating shaft 102 at its center. The stator 100 and the rotor 101 share the rotating shaft 102 as their central axis and are held together while maintaining a certain gap between them. The steel plates constituting the stator 100 and rotor 101 are mainly made of electrical steel, but are not limited to magnetic materials.

[0011] (Figure 2) The rotor 101 is composed of a rotor core 101a. Figure 2 shows a portion of the rotor core 101a, with the upper side of the drawing being the radially outer side and the lower side being the radially inner side. Multiple holes are formed in the rotor core 101a at arbitrary positions. The multiple holes formed in the rotor core 101a include magnet embedding holes 202 in which permanent magnets 201 are embedded, and through holes 203 formed radially inward from the magnet embedding holes 202 and in which permanent magnets 201 are not embedded. Furthermore, a rotating shaft 102 (Figure 1), not shown, is provided further radially inward from the through holes 203 in the rotor core 101a. The type and number of permanent magnets 201 are not limited.

[0012] The through-hole 203 penetrates the rotation shaft 102 in the axial direction and is located on or near the center of the magnetic poles in the rotor 101, and is formed in a position that does not interfere with the magnet embedding hole 202. Figure 2 shows the magnetic pole center line 205 as the center of the magnetic pole. The through-hole 203 is formed for purposes other than improving magnetization, which will be described later, such as reducing the weight of the rotor 101. The through-hole 203 has a protrusion 204 that projects radially inward (inner circumference) from the inner wall on the radially outer side (outer circumference side) of the through-hole 203 along the magnetic pole center line 205.

[0013] The magnet embedding holes 202 and the through holes 203 are formed by punching out a portion of the rotor core 101a in the axial direction using a tool (not shown). Thus, the protrusions 204 are formed integrally with the rotor core 101a. The manufacturing method of the rotor core 101a is not limited to this punching method, and other methods such as wire cutting may also be used. Furthermore, the through holes 203 are not limited to being located on the magnetic pole centerline 205, but may be located, for example, between the magnetic pole centerline 205 and a magnetic pole (not shown) adjacent to the magnetic pole centerline 205 in the rotor core 101a, and may be formed to be symmetrical in the circumferential direction with respect to the magnetic pole centerline 205 or the magnetic pole (not shown).

[0014] (Regarding the manufacturing method of rotors) (Figure 3) Rotating electric machine 1 is a magnetic motor that uses a permanent magnet 201 as the source of a magnetic field. However, when embedding the permanent magnet 201 in the rotor 101 (rotor core 101a), if the permanent magnet 201 is embedded while magnetized, it will adhere to the rotor 101, reducing manufacturability. Therefore, in rotating electric machine 1, the permanent magnet 201 is first inserted into the magnet embedding hole 202 of the rotor 101, and then a magnetic field is generated by the magnetization process described later, causing the permanent magnet 201 to become magnetized by that magnetic field. In this way, the rotor 101 is manufactured by the post-magnetization process.

[0015] The magnetization process of the rotor 101 uses a first magnetization section 31, which consists of a main yoke 31a and a main winding 31b. The first magnetization section 31 is provided on the outer circumference of the rotor 101. In the first magnetization section 31, the main winding 31b is wound around the main yoke 31a. By energizing the main winding 31b, a magnetic flux is generated passing through the main yoke 31a, and a magnetic flux is generated from the first magnetization section 31.

[0016] Here, the magnetic flux generated in the first magnetization portion 31 only passes near the outer periphery of the rotor 101, and there is a possibility that the magnetic flux may not reach the inner peripheral side. Therefore, in the present invention, in order to allow the magnetic flux to pass as far as possible from the radially outer side to the radially inner side of the rotor core 101a up to a position close to the position where the rotation axis is provided, an auxiliary winding 32b is wound around the convex portion 204 of the through hole 203 to provide the second magnetization portion 32. By doing so, a current is passed through the main winding 31b of the first magnetization portion 31 to generate a first magnetic field, and a current is passed through the auxiliary winding 32b of the second magnetization portion 32 to generate a second magnetic field, so that the magnetic flux can pass from the outer peripheral side to the inner peripheral side of the rotor core 101a to magnetize the permanent magnet 201.

[0017] (Dimensions Constraint of Through Hole) (Fig. 4) As shown in FIG. 3, the convex portion 204 is provided with the second magnetization portion 32 by inserting the auxiliary winding 32b and functions as an auxiliary yoke of the main yoke 31a. In one embodiment of the present invention, the dimensions of the through hole 203 are restricted as follows in order to facilitate the insertion of the auxiliary winding 32b. Specifically, when the side of the convex portion 204 and the side of the inner wall surface of the through hole 203 have a relatively linear shape, in the radial direction of the through hole 203, the first shortest distance 401 between the convex portion 204 (the tip 204a thereof) and the radially inner radial inner wall 203a is equal to or smaller than the second shortest distance 402 between the convex portion 204 (the convex portion circumferential inner wall 204b thereof) and the circumferential inner wall 203b of the through hole 2O3 in the circumferential direction.

[0018] With such a configuration, if the outer diameter width of the auxiliary winding 32b inserted into the through hole 203 for winding around the convex portion 204 is set to be smaller than the first shortest distance 401, the auxiliary winding 32b can be wound around the convex portion 204 without interfering with the rotor core 101a when inserted into the through hole 203. Moreover, even when the auxiliary winding 32b has an outer dimension close to the second shortest distance 402 when wound around the convex portion 204, the auxiliary winding 32b does not interfere with the rotor core 101a. Therefore, the insertability of the auxiliary winding in the manufacturing process is improved, and the productivity of the rotor 101 can be improved.

[0019] The present invention is compared with the conventional configuration. In the conventional configuration, for example, when only an auxiliary yoke is inserted into the through-hole of the rotor core, since the auxiliary yoke, which is the inserted magnetizing core, is separate from the rotor core, a gap (magnetic gap) formed between the auxiliary yoke and the rotor core cannot be filled and the magnetic flux becomes difficult to pass through, resulting in a problem that the magnetic field is suppressed. However, according to the embodiments and manufacturing method of the present invention, a magnetizing device is constituted by winding an auxiliary winding 32b around a convex portion 204 formed on the inner wall of the through-hole. Further, since the convex portion 204 is integrally formed with the rotor core 101a, there is no gap (magnetic gap) in the through-hole 203 and there is no magnetic barrier, so that the magnetic flux can easily pass through. By doing so, the strength of the magnetic field on the inner diameter side of the rotor core 101a can be improved, and the reliability of the motor performance can be ensured by improving the magnetizability. Further, as a secondary effect, since the displacement difference between the inner circumference and the outer circumference of the rotor core 101a can be reduced by the centrifugal force of the convex portion 204, it contributes to the suppression of stress. It can also contribute to expanding the degree of freedom in the magnetic circuit design of the motor 1.

[0020] (First Modified Example) (FIG. 5) In the above-described embodiment, an example in which the inner wall 204b in the circumferential direction of the convex portion 204 and the inner wall 203b in the circumferential direction of the through-hole 203 are parallel has been described. However, in this modified example, the inner wall 204b in the circumferential direction of the convex portion 204 and the inner wall 203b in the circumferential direction of the through-hole 203 are not parallel to each other. Specifically, the inner wall 204b in the circumferential direction of the convex portion 204 and the inner wall 203b in the circumferential direction of the through-hole 203 are formed as sides of the through-hole 203 and the convex portion 204 such that the extension line of the inner wall 204b in the circumferential direction of the convex portion and the extension line of the inner wall 203b in the circumferential direction form an acute angle toward the outer side in the radial direction of the rotor core 101a. In other words, it is formed such that the circumferential length of the root 204c of the convex portion 204 is larger than the circumferential length of the tip 204a of the convex portion 204. The angle 505 is illustrated as a predetermined angle formed by the acute angle.

[0021] This configuration ensures that the auxiliary winding 32b (Figure 3), inserted between the radial inner wall 203a of the through-hole 203 and the tip 204a of the protrusion 204, is securely held between the circumferential inner wall 203b and the circumferential inner wall 204b of the protrusion. Furthermore, it improves the ease of inserting the auxiliary winding 32b during the manufacturing process and facilitates the positioning of the auxiliary winding 32b within the through-hole 203. In addition, because the installation position of the auxiliary winding 32b within the through-hole 203 is fixed, variations in magnetization performance can be suppressed.

[0022] (Second variation) (Figure 6) In this modified example, the wall shapes of the through hole 203 and the protrusion 204 are curved, not straight as described above. In this modified example, an example is shown in which the protrusion 204 is formed in a curved shape from its base to its tip. The protrusion 204 has an inflection portion 508 at its base. If the distance from the radial inflection portion 508 to the tip 204a of the protrusion 204 is defined as the protrusion distance 506, then the protrusion distance 506 is made greater than the maximum distance 507 between the protrusion 204 and the inner wall of the through hole 203. The protrusion length 506 is the length from the apex of the inflection portion 508 with the greatest curvature to the tip 204a, which is the apex of the protrusion 204. Furthermore, the protrusion length 506 and the maximum distance 507 are made greater than the auxiliary winding 32b (Figure 3).

[0023] With this configuration, the entire auxiliary winding 32b inserted into the through hole 203 can be brought into close contact with the protrusion 204. Even if the through hole 203 and the protrusion 204 have a curved shape, the magnetic flux generated from the auxiliary winding 32b can pass through the protrusion 204, thereby suppressing variations in magnetization and improving magnetization.

[0024] (Variations in the manufacturing method of the rotor) (Figure 7) In the manufacturing method shown in Figure 3, only the protrusion 204 around which the auxiliary winding 32b is wound is formed and functions as an auxiliary yoke. However, in this modified example, after inserting the auxiliary winding 32b into the through hole 203 and placing it on the protrusion 204, an auxiliary core 32a is additionally inserted between the radial inner wall 203a of the through hole 203 and the protrusion 204. This allows the auxiliary core 32a to fix the auxiliary winding 32b so that it does not move radially inward, and the presence of the auxiliary core 32a reduces the gap in the through hole 203, thereby forming a magnetic path for the magnetic flux generated by the second magnetization unit 32 and allowing the magnetic flux to pass to the inner diameter side of the rotor core 101a. This improves the magnetization.

[0025] 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]

[0026] 1. Rotating electric machine 31 First magnetized part 31a Main York 31b Main winding 32 Second magnetized part 32a Auxiliary core 32b Auxiliary winding 100 stator 100a stator core 101 Rotor 101a Rotor core 102 Rotation axis 201 Magnet 202 Magnet burial hole 203 Through hole 203a Radial inner wall 203b Circumferential inner wall 204 Convex part 204a Protruding tip 204b Inner wall in the circumferential direction of the protrusion 204c Base of the protruding part 205 Magnetic pole center line 401 1st shortest distance 402 2nd shortest distance 505 angle 506 Protrusion length 507 Maximum distance between the protrusion and the inner wall of the through hole 508 Inflection

Claims

1. A rotor core having a permanent magnet, a magnet embedding hole for embedding the permanent magnet, and a through hole located radially inward from the magnet embedding hole and on the center of the magnetic pole, and penetrating in the axial direction, The rotor comprises a rotating shaft that penetrates the rotor core, The through-hole has a protrusion that projects radially inward from the radially outer inner wall and is located on the magnetic pole center, and is formed integrally with the rotor core. Rotor of a rotating electric machine.

2. The first shortest distance between the protrusion and the inner wall in the radial direction is equal to or less than the second shortest distance between the protrusion and the inner wall in the circumferential direction. The rotor of the rotating electric machine according to claim 1.

3. The extension line of the circumferential wall surface of the protrusion and the extension line of the inner wall in the circumferential direction form an acute angle toward the radially outward direction. The rotor of the rotating electric machine according to claim 2.

4. In the aforementioned protrusion, the distance from the base to the tip is greater than the maximum distance between the protrusion and the inner wall. The rotor of the rotating electric machine according to claim 3.

5. A method for manufacturing a rotor having a rotor core that includes a permanent magnet, a magnet embedding hole for embedding the permanent magnet, and a through hole that is radially inward from the magnet embedding hole and located on the center of the magnetic pole, and penetrates in the axial direction, A protrusion is formed in the through hole, which is integral with the rotor core. A first magnetization section, consisting of a main winding and a main yoke, is provided on the outer circumference of the rotor. A second magnetization portion is provided in the through hole, which is formed by winding an auxiliary winding around the protrusion. The permanent magnet is magnetized by passing an electric current through the first magnetization section to generate a first magnetic field, and by passing an electric current through the second magnetization section to generate a second magnetic field. A method for manufacturing the rotor of a rotating electric machine.

6. In the through hole, an auxiliary iron core is inserted between the radially inner wall of the through hole and the protrusion. A method for manufacturing the rotor of a rotating electric machine according to claim 5.

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