CN114930684A - Rotor core and rotating electrical machine - Google Patents
Rotor core and rotating electrical machine Download PDFInfo
- Publication number
- CN114930684A CN114930684A CN202180008215.6A CN202180008215A CN114930684A CN 114930684 A CN114930684 A CN 114930684A CN 202180008215 A CN202180008215 A CN 202180008215A CN 114930684 A CN114930684 A CN 114930684A
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- China
- Prior art keywords
- rotor core
- flat portion
- curved
- tooth
- flat
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Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K1/00—Details of the magnetic circuit
- H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
- H02K1/22—Rotating parts of the magnetic circuit
- H02K1/26—Rotor cores with slots for windings
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K23/00—DC commutator motors or generators having mechanical commutator; Universal AC/DC commutator motors
- H02K23/02—DC commutator motors or generators having mechanical commutator; Universal AC/DC commutator motors characterised by arrangement for exciting
- H02K23/04—DC commutator motors or generators having mechanical commutator; Universal AC/DC commutator motors characterised by arrangement for exciting having permanent magnet excitation
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Dc Machiner (AREA)
- Iron Core Of Rotating Electric Machines (AREA)
Abstract
The rotor core of a rotating electrical machine of the present invention is capable of adjusting the flow of magnetic flux at the tip end portions of teeth. The rotor core of the rotating electric machine includes: a slot portion for winding the coil; and a tooth portion that forms a space in which a coil is wound around the groove portion, wherein a boundary portion between an inner peripheral side of the tooth portion and the groove portion is formed by a flat portion and a curved portion, the flat portion is formed in a straight line shape perpendicular to a radial direction, the curved portion is formed in a curved line shape that continues to the flat portion via an inflection point provided at a boundary with the flat portion, and the curved portion is located closer to a tip end than the flat portion in a circumferential direction of the tooth portion.
Description
Technical Field
The present invention relates to a rotating electric machine typified by a dc motor, and particularly to a structure of a rotor core.
Background
The brush motor energizes a coil wound around an armature core, and generates torque by an action of a magnetic field generated by a magnet. As a background art in this field, there is Japanese patent laid-open No. 2006-280172 (patent document 1). Japanese patent application laid-open No. 2006-280172 discloses a dc motor in which the inner center of curvature of a magnet disposed in a case of the dc motor is eccentric in the radial direction from the outer center of curvature thereof, and the inner center of curvature of the tip end of an iron core of an armature is eccentric in the opposite tip end direction from the outer center of curvature thereof (see abstract).
Documents of the prior art
Patent document
Patent document 1: japanese patent laid-open No. 2006-280172
Disclosure of Invention
Problems to be solved by the invention
In the brush motor, torque at the time of rotation varies with the rotation angle of the motor, and this torque ripple affects controllability of the actuator, and becomes a factor of reducing productivity such as deterioration of system response. Therefore, reduction of cogging torque is required. In the above-described background art, the flow of magnetic flux is adjusted by providing an eccentric amount in the inner peripheral portion of the core groove and changing the shape of the tip end portion of the core. Therefore, if the inner diameter eccentricity is increased, the tip end portion becomes narrow, and therefore the degree of freedom in adjusting the flow of magnetic flux is low, and the characteristics desired for the motor may not be obtained.
Means for solving the problems
A typical example of the invention disclosed in the present application is as follows. That is, a rotor core for a rotating electrical machine is provided with: a slot portion for winding the coil; and a tooth portion that forms a space in which a coil is wound around the groove portion, wherein a boundary portion between an inner peripheral side of the tooth portion and the groove portion is formed by a flat portion and a curved portion, the flat portion is formed in a straight line shape perpendicular to a radial direction, the curved portion is formed in a curved line shape that continues to the flat portion via an inflection point provided at a boundary with the flat portion, and the curved portion is located closer to a tip end than the flat portion in a circumferential direction of the tooth portion.
ADVANTAGEOUS EFFECTS OF INVENTION
According to the present invention, the flow of magnetic flux at the tip portion of the tooth can be adjusted. Problems, configurations, and effects other than those described above will be apparent from the following description of the embodiments.
Drawings
Fig. 1 is a longitudinal sectional view showing a structure of a dc motor according to an embodiment of the present invention.
Fig. 2 is an exploded perspective view of a dc motor according to an embodiment of the present invention.
Fig. 3 is a perspective view showing a structure of an armature core according to an embodiment of the present invention.
Fig. 4 is a cross-sectional view showing the configuration of a dc motor according to an embodiment of the present invention.
Fig. 5 is a diagram showing an effect of the armature core according to the embodiment of the present invention.
Detailed Description
Hereinafter, an exemplary embodiment of a dc motor in a rotating electrical machine will be described with reference to fig. 1 to 5.
Fig. 1 is a sectional view showing the structure of a dc motor 1 according to the present embodiment, and shows a vertical section taken along a shaft 5. Fig. 2 is an exploded perspective view of the dc motor 1 of the present embodiment.
The dc motor 1 generates a rotational torque by supplying power between the external power supply terminals 26, and transmits the torque to the system side via the attached motor gear 19. The dc motor 1 has a yoke 2, and the yoke 2 functions to form a housing and a magnetic circuit. The magnetic stays 27 and the plurality of magnets 3 are attached to the inner surface of the yoke 2, and generate magnetic flux as permanent magnets. Further, an armature 4 is housed inside the magnet 3 with an arbitrary gap from the inner surface of the magnet 3. A shaft 5 connected to a motor gear 19 is provided at a radially central portion of the armature 4. The shaft 5 is rotatably supported by the front bracket 7 and the rear bracket 21 via a bearing 6 and a bearing 20, and outputs torque generated by the armature core 8 and the magnet 3. The front bracket 7 and the rear bracket 21 are mounted on the yoke 2. The armature 4 is configured by fixing an armature core 8 and a commutator 9 to the shaft 5. The armature coil 11 is wound between a plurality of slots 10 formed in the outer circumferential portion of the armature core 8 in the circumferential direction. The commutator 9 is formed in a cylindrical shape from an insulating material such as resin, and a plurality of commutator segments 12 made of a conductive material are provided on the outer periphery of the commutator 9. The commutator segments 12 are electrically engaged with the armature coils 11 wound between the slots 10.
A brush holder 13 is housed inside the yoke 2. At least one pair of brushes 14 and springs 15 for supplying power to the commutator segments 12 are arranged on the brush holder 13. A choke coil 16 for removing electromagnetic noise is also disposed on the brush holder 13. The brush 14 is electrically connected to an external power supply terminal 26 of the dc motor 1. The brushes 14 are in sliding contact with the outer peripheral surface of the commutator segments 12 by the elasticity of the springs 15 held by the brush holders 13, and supply power to the armature coil 11 via the commutator segments 12. Thereby, the external power supply terminal 26 is electrically connected to the armature coil 11 to form an electric circuit.
Fig. 3 is a perspective view showing the structure of the armature core 8 of the present embodiment.
The armature core 8 is formed by laminating soft magnetic metal plates such as electromagnetic steel plates, and is provided with slots 10, which are slots for winding the armature coil 11, and teeth 81 which constitute a magnetic path through which magnetic flux passes. The teeth 81 are formed in a T-shape by a radially extending portion extending radially from the rotation center and a circumferentially extending portion extending laterally in the circumferential direction at the tip of the radially extending portion. The adjacent teeth 81 are interrupted by the groove opening 82 on the outer peripheral side, and the groove 10 communicates with the outside in the radial direction through the groove opening 82. The illustrated armature core 8 is of a skewed slot (twisted) type having a slot opening 82 formed obliquely, and reduces torque variation accompanying rotation of the motor.
The slots 10 are formed as spaces between adjacent teeth 81, and the number of slots is the number of armature cores 8 divided in the circumferential direction by the teeth 81.
Fig. 4 is a sectional view showing the structure of the dc motor 1 of the present embodiment, and mainly shows the shape of the teeth 81 using a cross section cut on a plane perpendicular to the shaft 5.
The outer peripheral side of the teeth 81 is formed by a predetermined arc centered on the shaft 5 so as to maintain an arbitrary gap from the inner surface of the magnet 3. The inner periphery of the teeth 81 (the boundary surface on the outer periphery of the groove 10) is constituted by flat portions 83 formed linearly perpendicular to the radial direction of the teeth 81 and curved portions 84 formed by curved lines having different curvatures from those of the flat portions 83. The flat portion 83 and the curved portion 84 are continuously connected, and an inflection point 85 in which curvature changes is formed at the boundary thereof. In the flat portion 83 and the curved portion 84, the flat portion 83 is formed to be left-right uniform on the inner side and the curved portion 84 is formed to be left-right uniform on the outer side as viewed from the radial center line of each tooth 81. As described above, the flat portion 83 is ideally formed in a straight line perpendicular to the radial direction of the teeth 81, but may be allowed to have an error (for example, a ± 0.2mm irregularity or inclination) within a predetermined range from the perpendicular straight line. The predetermined error may be determined by the radial width of the circumferential extension of the teeth 81, the thickness of the electromagnetic steel sheet constituting the armature core 8, or the like. The curved portion 84 is formed of a curved surface having a curvature different from that of the flat portion 83, but is preferably formed in a concentric circle shape around the rotation axis.
In the present embodiment, since the flat portion 83 is provided inside the tip portion of the tooth 81 and the curved portion 84 forms the outside of the inflection point 85, the width of the circumferential extension of the tip portion of the tooth 81 is increased at a position close to the radial extension of the tooth 81 and is decreased at a position away from the radial extension, the flow of magnetic flux passing through the tip portion of the tooth 81 can be adjusted, and cogging torque can be reduced.
Further, since the radial width of the portion of the circumferential extending portion formed in the T shape close to the radial extending portion is increased, the magnetic flux of the armature core 8 reaches the tip end of the circumferential extending portion, and thus the decrease in the magnetic flux density at the position of the slot opening 82 can be suppressed, and the cogging torque can be reduced. On the other hand, if the radial width of the circumferential extension portion is made wider, the space factor of the armature coil 11 decreases, and the torque decreases. Therefore, the range of the flat portion 83 is adjusted, cogging torque is reduced, and reduction in torque is suppressed.
Further, regarding the angular range in the circumferential direction in which the flat portion 83 is formed (the angle formed by the line connecting the end (inflection point 85) of the flat portion 83 and the rotation center) θ s, if the flat portion 83 is formed in the following formula range using the angular range occupied by the magnet 3 for each pole (i.e., the range in which the magnet 3 contacts the inner surface of the yoke 2) θ e, the number of poles p (2 in the drawing) of the magnet 3, and the number of slots s (5 in the drawing) of the armature core 8, it can be seen that the reduction in cogging torque is suitable.
θs÷θα＝0.5～0.7θα＝θe×p÷s
In the above equation, θ α is an angle obtained by dividing the angle occupied by the magnet 3 over the entire circumference by the number of slots, and is a parameter indicating the angle occupied by the magnet 3 in each slot.
Fig. 5 is a diagram showing the effect of the armature core 8 of the present embodiment, and is a diagram showing a change in cogging torque when the range of the flat portion 83 is changed. In fig. 5, θ s ÷ θ α (the ratio of the range θ s of the flat portion 83 to θ α) is taken as the horizontal axis, and the ratio of the cogging torque based on the case where no flat portion 83 is provided (θ s ═ θ o) is taken as the vertical axis.
According to fig. 5, if θ α is increased from θ s ÷ θ o (if the range of the flat portion 83 is widened), the cogging torque decreases, and the cogging torque decreases within a range of θ s ÷ θ α of 0.5 to 0.7. Then, if θ α increases, the cogging torque increases. From this, it is understood that the range of θ s ÷ θ α is a range in which the cogging torque can be reduced, and the range of θ s ÷ θ α is 0.5 to 0.7.
As described above, since the boundary portion with the slot 10 on the inner peripheral side of the tooth 81 is formed by the flat portion 83 and the curved portion 84, the flat portion 83 is formed in a straight line shape perpendicular to the radial direction, the curved portion 84 is formed in a curved line shape continuing to the flat portion 83 via the inflection point 85 provided at the boundary with the flat portion 83, and the curved portion 84 is located at the tip end of the flat portion 83 in the circumferential direction of the tooth 81, the magnetic flux at the tip end portion of the tooth 81 can be changed, the magnetic change generated at the time of the motor rotation can be adjusted, the magnetic flux at the end portion of the tooth 81 can be increased, the decrease in torque can be suppressed, and the cogging torque can be reduced. Further, by extending the curved portion 84 from the inflection point 85 concentrically with the outer diameter side of the armature core 8, the radial width of the tip end portion of the tooth 81 is not reduced, and deformation of the armature core 8 due to centrifugal force when the dc motor 1 rotates can be suppressed. In addition, the degree of freedom in adjusting the opening width of the groove opening 82 can be increased. Therefore, the tips of the teeth 81 do not become sharp, and damage to the armature coil 11 due to the armature coil 11 being caught by the armature core 8 during coil winding can be suppressed.
The present invention is not limited to the above-described embodiments, and includes various modifications and equivalent configurations within the spirit of the appended claims. For example, the above embodiments are described in detail to explain the present invention easily and understandably, and the present invention is not limited to having all the configurations described. In addition, a part of the configuration of one embodiment may be replaced with the configuration of another embodiment. In addition, the configuration of one embodiment may be added to the configuration of another embodiment. Further, some of the configurations of the embodiments may be added, deleted, or replaced with other configurations.
Description of the symbols
1 DC motor, 2 magnetic yokes, 3 magnets, 4 armatures, 5 shafts, 6 bearings, 7 front brackets, 8 armature cores, 9 commutators, 10 slots, 11 armature coils, 12 commutators, 13 brush holders, 14 brushes, 15 springs, 16 choking coils, 19 motor gears, 20 bearings, 21 rear brackets, 26 external power supply terminals, 27 magnetic supporting strips, 81 teeth, 82 slot openings, 83 flat parts, 84 curved parts and 85 inflection points.
Claims (3)
1. A rotor core of a rotating electrical machine, the rotor core comprising:
a slot portion for winding the coil; and
a tooth portion forming a space for the coil to be wound around the groove portion,
a boundary portion between the inner peripheral side of the tooth portion and the groove portion is formed by a flat portion formed in a straight line shape perpendicular to a radial direction and a curved portion formed in a curved line shape continuous to the flat portion via an inflection point provided at a boundary with the flat portion,
the curved portion is located closer to the tip than the flat portion in the circumferential direction of the tooth portion.
2. The rotor core of claim 1,
using an angle thetas between the inflection points as viewed from the center of rotation, an angle thetae occupied by the magnets for each pole, the number p of poles of the magnets, and the number s of the grooves,
θ s ÷ (θ e × p ÷ s) is in the range of 0.5 to 0.7.
3. A rotating electric machine, characterized in that,
a rotor core having the rotor core according to claim 1 or 2; and
and a magnet disposed on an outer peripheral side of the rotor core.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2020-020436 | 2020-02-10 | ||
| JP2020020436 | 2020-02-10 | ||
| PCT/JP2021/001180 WO2021161714A1 (en) | 2020-02-10 | 2021-01-15 | Rotor core and rotary electric machine |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114930684A true CN114930684A (en) | 2022-08-19 |
Family
ID=77292999
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202180008215.6A Pending CN114930684A (en) | 2020-02-10 | 2021-01-15 | Rotor core and rotating electrical machine |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JP7390463B2 (en) |
| CN (1) | CN114930684A (en) |
| WO (1) | WO2021161714A1 (en) |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003018773A (en) | 2001-06-28 | 2003-01-17 | Sankyo Seiki Mfg Co Ltd | Motor with core |
| JP2006333584A (en) | 2005-05-24 | 2006-12-07 | Mitsumi Electric Co Ltd | Motor |
| JP4886331B2 (en) | 2006-03-27 | 2012-02-29 | 株式会社ミツバ | Armature core in rotating electrical machines |
-
2021
- 2021-01-15 CN CN202180008215.6A patent/CN114930684A/en active Pending
- 2021-01-15 JP JP2022500277A patent/JP7390463B2/en active Active
- 2021-01-15 WO PCT/JP2021/001180 patent/WO2021161714A1/en active Application Filing
Also Published As
| Publication number | Publication date |
|---|---|
| WO2021161714A1 (en) | 2021-08-19 |
| JPWO2021161714A1 (en) | 2021-08-19 |
| JP7390463B2 (en) | 2023-12-01 |
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| PB01 | Publication | ||
| PB01 | Publication | ||
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