JP2016086570A - Rotor and motor using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnet embedded type rotor having durability and a motor including the rotor.SOLUTION: A rotor includes a rotor core 20 having an outer edge 21 and a permanent magnet. In the rotor core 20, a magnet housing hole for housing the permanent magnet and a gap part 24 are formed. A bridge part 25 between the gap part 24 and the outer edge 21 includes first to third bridges 31-33 and first to second openings 41-42. The second bridge 32 and the third bridge 33 are located further inward in the radial direction than the first bridge 31 and further inward in the radial direction than the second bridge 32, respectively. The first opening 41 and the second opening 42 are located between the first bridge 31 and the second bridge 32 and between the second bridge 32 and the third bridge 33, respectively. The width W2 of the second bridge 32 is greater than the width W1 of the first bridge 31. The width W3 of the third bridge 33 is greater than the width W2 of the second bridge 32.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a rotor and a motor using the rotor.

  Some motors have a rotor with embedded permanent magnets. Such a magnet-embedded rotor is used with a stator to which an exciting coil for generating a magnetic flux by passing an electric current is attached.

  The embedded magnet rotor has a rotor core and a permanent magnet. The rotor core has a plurality of magnet accommodation holes, each of which accommodates one permanent magnet. Depending on the number of permanent magnets housed in the rotor core, the rotor has a plurality of magnetic poles. The magnetic flux generated from these magnetic poles interacts with the magnetic flux generated from the exciting coil, thereby generating rotation of the rotor.

  Thus, the motor generates power by the interaction between the rotor and the stator. Therefore, if the magnetic flux generated from one of the magnetic poles of the rotor is magnetically short-circuited with the adjacent magnetic poles in the rotor instead of the stator, the conversion efficiency from electrical energy to mechanical power energy deteriorates. . Therefore, it is preferable that adjacent magnetic poles in the rotor are magnetically interrupted. However, in a magnet-embedded rotor, since a part of the rotor core is interposed between adjacent magnets, a magnetic short circuit is likely to occur.

  In order to suppress a magnetic short circuit between the magnetic poles, Patent Document 1 (Japanese Patent Laid-Open No. 2013-188023) proposes to provide a through hole called a “flux barrier” in the rotor. However, the presence of such holes may deteriorate the durability of the rotor against stresses caused by the rotation and vibration of the rotor.

  An object of the present invention is to provide a magnet embedded rotor having durability, and a motor having such a rotor.

  A rotor according to a first aspect of the present invention includes a rotor core and a magnet. The rotor core has an outer edge. A magnet housing hole and a gap are formed in the rotor core. A magnet accommodation hole accommodates a magnet. The gap portion extends from the magnet accommodation hole. The rotor core has a bridge portion. The bridge portion is located between the gap portion and the outer edge. The bridge unit has a plurality of bridges. The plurality of bridges include a first bridge, a second bridge, and a third bridge. The second bridge is located on the radially inner side than the first bridge. The third bridge is located on the radially inner side than the second bridge. A plurality of openings are formed in the bridge portion. The plurality of openings have a first opening and a second opening. The first opening is located between the first bridge and the second bridge. The second opening is located between the second bridge and the third bridge. The width of the second bridge is larger than the width of the first bridge. The width of the third bridge is larger than the width of the second bridge.

  According to this configuration, a magnet-embedded rotor having durability against stress can be obtained. Such a rotor is likely to be used for a high-speed motor.

  In the rotor according to the second aspect of the present invention, in the rotor according to the first aspect, the first opening and the second opening at least partially overlap in the radial direction.

  According to this structure, the magnetic short circuit between the magnetic poles which a rotor adjoins can be suppressed more.

  In the rotor according to the third aspect of the present invention, in the rotor according to the second aspect, the gap portion overlaps at least partially in the radial direction with both the first opening and the second opening.

  According to this configuration, the magnetic short circuit between the adjacent magnetic poles of the rotor can be further suppressed as compared with the configuration of the second aspect.

  A motor according to a fourth aspect of the present invention includes the rotor according to any one of the first to third aspects and a coil. The coil can rotate the rotor in cooperation with the magnet by passing current through it.

  According to this configuration, a durable motor can be obtained. Such a motor is likely to rotate the rotor at high speed.

  The rotor according to the first aspect of the present invention has durability against stress.

  The rotor according to the second or third aspect of the present invention can suppress a magnetic short circuit between adjacent magnetic poles of the rotor.

  The motor according to the fourth aspect of the present invention has durability.

It is a top view of the rotor which concerns on this invention. It is sectional drawing of the rotor cut | disconnected by the II-II line | wire of FIG. It is the schematic of the structure of the motor using the rotor shown in FIG. It is an enlarged view of the bridge part which the rotor shown in FIG. 1 has.

  Hereinafter, an embodiment of a rotor and a motor according to the present invention will be described with reference to FIGS. The specific configurations of the rotor and the motor included in the present invention are not limited to the embodiments described below. The specific configuration can be changed as appropriate without departing from the scope of the invention.

(1) Overall Configuration As shown in FIGS. 1 and 2, the rotor 10 has a cylindrical shape surrounding the central axis C as a whole. The rotor 10 includes a rotor core 20, four permanent magnets 50, and two end plates 70. However, in FIG. 1, the end plate 70 is omitted.

  FIG. 3 shows a motor 100 using the rotor 10 shown in FIGS. 1 and 2.

(2) Configuration of rotor 10 (2-1) Rotor core 20
As shown in FIGS. 1 and 2, the rotor core 20 has a thick cylindrical shape as a whole, and is made of, for example, a plurality of stacked disc-shaped steel plates. As shown in FIG. 2, the rotor core 20 has an upper surface 27, a lower surface 28, and an outer edge 21 that connects the upper surface 27 and the lower surface 28.

  As shown in FIG. 1, the rotor core 20 has a shaft holding hole 22, a magnet accommodation hole 23, and a gap portion 24. Furthermore, the rotor core 20 has a bridge portion 25 described later.

(2-1-1) Shaft holding hole 22
The shaft holding hole 22 is a through-hole penetrating the rotor core 20 in parallel with the central axis C, and is for holding the shaft 110 (see FIG. 3) that functions as the rotation axis of the rotor 10.

(2-1-2) Magnet housing hole 23
The four magnet accommodation holes 23 are all through-holes penetrating the rotor core 20 in parallel with the central axis C, and are for accommodating the permanent magnets 50.

(2-1-3) Cavity 24
The gap 24 is a through-hole penetrating the rotor core 20 in parallel with the central axis C, and is a space extending from the end of the magnet accommodation hole 23. The gap portion 24 does not accommodate the permanent magnet 50.

(2-1-4) Bridge portion 25
The bridge part 25 is a part of the rotor core 20 and is a relatively narrow part located between the outer edge 21 and the gap part 24. One bridge portion 25 is located between two adjacent ones of the four magnetic pole centers P1 to P4 described later in section (2-2). By narrowing the radial width WB (see FIG. 4) of the bridge portion 25, it is possible to suppress two magnetic poles each including the two adjacent magnetic pole centers from being magnetically short-circuited. Thereby, the magnetic flux generated by each permanent magnet 50 can efficiently interact with the stator 120 (see FIG. 3) disposed outside the rotor 10 so as to surround the rotor 10.

  In general, the smaller the width WB (see FIG. 4) in the radial direction of the bridge portion 25, the greater the effect of suppressing the magnetic short circuit. The suppression effect will be described later with reference to FIG. 4 in section (4).

(2-2) Permanent magnet 50
As shown in FIG. 1, the permanent magnet 50 is installed in the magnet accommodation hole 23 of the rotor core 20 in order to give a magnetic pole to the rotor 10.

  In the present embodiment, the number of permanent magnets 50 is four. However, other numbers of permanent magnets 50 and magnet housing holes 23 may be provided according to design requirements.

  Each of the magnetic pole centers P1 to P4 appears on the outer edge 21 shown in FIG. 1 at a location closest to the center of one of the permanent magnets 50.

(2-3) End plate 70
The end plate 70 is a disk made of stainless steel, which is a nonmagnetic material, for example. As shown in FIG. 2, two end plates 70 are attached to the upper surface 27 and the lower surface 28 of the rotor core 20 to prevent the permanent magnet 50 arranged in the magnet accommodation hole 23 from going out. . A shaft passage hole 72 for allowing the shaft to pass therethrough is formed at the center of each end plate 70.

  When the permanent magnet 50 is fixed to the rotor core 20 by any method other than the end plate 70, the end plate 70 is not necessarily provided.

(2-4) Others The rotor core 20 and the end plate 70 can be fixed to each other by various methods, for example, by a fastener such as a rivet. In that case, each of the rotor core 20 and the end plate 70 may have a through hole for allowing the fastener to pass therethrough.

(3) Configuration of Motor 100 FIG. 3 is a schematic diagram of the structure of the motor 100 using the rotor 10 shown in FIGS. 1 and 2.

  The motor 100 has a casing 130 in which the rotor 10 and the stator 120 are installed.

  A shaft 110 is fixed to the shaft holding hole 22 of the rotor 10. The shaft 110 is supported by a bearing (not shown) and can rotate.

  The stator 120 is disposed so as to surround the rotor 10. The stator 120 is provided with a plurality of exciting coils 125. In the present embodiment, the number of exciting coils 125 is four. However, other numbers of exciting coils 125 may be provided according to design requirements.

  Each of these four exciting coils 125 is selectively excited sequentially according to a predetermined sequence. As a result, an attractive force or a repulsive force is generated between the excited exciting coil 125 and one of the magnetic pole centers P1 to P4 of the rotor 10, and the rotor 10 is rotated.

(4) Features (4-1) Formation of First Opening 41 and Second Opening 42 FIG. 4 is an enlarged view of the bridge portion 25. A first opening 41 and a second opening 42 are formed in the bridge portion 25. The first opening 41 and the second opening 42 are through-holes that penetrate the rotor core 20 and extend parallel to the central axis C of the rotor 10 (see FIG. 1 or 2).

  As shown in FIG. 4, the first opening 41 is located closer to the outer edge 21 than the second opening 42. It is preferable that the first opening 41 and the second opening 42 overlap at least partially in the radial direction. Here, “at least partially overlaps in the radial direction” means that one line segment extending from a place where the outer edge 21 is located to the central axis C penetrates two or more objects. Similarly, the gap 24 preferably overlaps the first opening 41 at least partially in the radial direction. In addition, the gap 24 preferably overlaps the second opening 42 at least partially in the radial direction. With respect to the rotor core 20 shown in FIG. 4, a single line segment extending from a place where the outer edge 21 is located to the central axis C penetrates all of the first opening 41, the second opening 42, and the gap portion 24.

  Due to the presence of the first opening 41 and the second opening 42, a first bridge 31, a second bridge 32, and a third bridge 33 are formed in the bridge portion 25, respectively. The first opening 41 separates the first bridge 31 and the second bridge 32, and the second opening 42 separates the second bridge 32 and the third bridge 33. The first bridge width W1, the second bridge width W2, the third bridge width W3, the first opening width WG1, the second opening width WG2, and the bridge portion width WB shown in FIG. This is the radial width of the rotor core 20 that the second bridge 32, the third bridge 33, the first opening 41, the second opening 42, and the bridge portion 25 have. In the present embodiment, the total W1 + W2 + W3 + WG1 + WG2 of the first bridge width W1, the second bridge width W2, the third bridge width W3, the first opening width WG1, and the second opening width WG2 is equal to the bridge portion width WB.

  It is considered that the effect of suppressing the magnetic short circuit between adjacent magnetic poles is reduced as the total W1 + W2 + W3 of the first bridge width W1, the second bridge width W2, and the third bridge width W3 is larger. The magnetic short-circuit suppressing effect that can be exhibited by the rotor core 20 of the present embodiment shown in FIG. 4 is a magnetic that can be exhibited by a rotor core that has a single bridge whose width is W1 + W2 + W3 and that has no opening. It is estimated that the effect is the same as the short-circuit suppressing effect.

  The inventors performed a stress analysis simulation for the two rotor cores shown in Table 1, that is, the rotor core A and the rotor core B, which can be expected to have a similar suppression effect. As a result, it was found that the rotor core B having an opening has higher stress resistance than the rotor core A having no opening.

(4-2) Sizes of the first bridge width W1, the second bridge width W2, and the third bridge width W3 The inventors perform further stress analysis simulation, and determine the size of the first to third bridge width total W1 + W2 + W3. It was verified how the widths W1, W2 and W3 of the respective bridges should be determined while keeping constant.

  As a result, the knowledge that the stress resistance of the rotor core having a smaller width toward the bridge closer to the outer edge 21 is relatively high was obtained. The rotor core 20 shown in FIG. 4 satisfies this condition. That is, the first bridge width W1 is smaller than the second bridge width W2, and the second bridge width W2 is smaller than the third bridge width W3.

(4-3) Others In the present embodiment, the number of bridges in the bridge unit 25 is three, and the number of openings is two. However, the number of bridges and openings included in the bridge portion 25 in the configuration of the present invention is not limited to these.

  The present invention is applicable to motors in all technical fields. For example, the present invention can be used for an air conditioning apparatus.

DESCRIPTION OF SYMBOLS 10 Rotor 20 Rotor core 21 Outer edge 22 Shaft holding hole 23 Magnet accommodation hole 24 Gap part 25 Bridge part 27 Upper surface 28 Lower surface 31 1st bridge 32 2nd bridge 33 3rd bridge 41 1st opening 42 2nd opening 50 Permanent magnet 70 End plate 72 Shaft passage hole 100 Motor 110 Shaft 120 Stator 125 Excitation coil 130 Casing C Central axis P1 Magnetic pole center P2 Magnetic pole center P3 Magnetic pole center P4 Magnetic pole center W1 First bridge width W2 Second bridge width W3 Third bridge width WG1 First opening width WG2 Second opening width WB Bridge width

JP2013-1888023A

Claims (4)

A rotor core (20) having an outer edge (21);
A magnet (50);
A rotor (10) comprising:
In the rotor core,
A magnet housing hole (23) for housing the magnet, and a gap (24) extending from the magnet housing hole;
Is formed,
The rotor core is
A bridge portion (25) located between the gap and the outer edge;
Have
The bridge part has a plurality of bridges (31, 32, 33),
The plurality of bridges are:
A first bridge (31);
A second bridge (32) located radially inward of the first bridge;
A third bridge (33) located radially inward of the second bridge;
Have
A plurality of openings (41, 42) are formed in the bridge portion,
The plurality of openings are
A first opening (41) located between the first bridge and the second bridge;
A second opening (42) located between the second bridge and the third bridge;
Have
The width (W2) of the second bridge is larger than the width (W1) of the first bridge,
The width (W3) of the third bridge is larger than the width (W2) of the second bridge,
Rotor (10).   The rotor according to claim 1, wherein the first opening and the second opening overlap at least partially in a radial direction.   3. The rotor according to claim 2, wherein the gap portion overlaps at least partially in the radial direction with both the first opening and the second opening. A rotor according to any one of claims 1 to 3;
A coil (125) capable of rotating the rotor in cooperation with the magnet by passing an electric current;
Comprising a motor.

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