JP2015070721A - Permanent magnet rotary electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a permanent magnet rotary electric machine in which distance between a permanent magnet of a rotor and a stator is reduced to obtain a large torque with a compact configuration, and the permanent magnet has stable falling-out prevention applied thereto.SOLUTION: A permanent magnet rotary electric machine includes: a stator composed of a laminated iron core around which a winding is wound; and a rotor whose outer periphery is separated from this stator by a gap and which has an annual laminated iron core whose inner peripheral side is fixed to a rotary shaft. The rotor incorporates a plurality of permanent magnets radially extending from the rotation center. The permanent magnet is located so that the end surface on the outer peripheral side of the rotor has almost the same surface as the outer peripheral surface of the rotor, and a cross sectional area in the axial direction is formed so as to be enlarged along the inner side in the radial direction of the rotor.

Description

  The present invention relates to a permanent magnet rotating electric machine in which a permanent magnet is embedded in a rotor (rotor), and more particularly to a permanent magnet rotating electric machine including permanent magnets embedded in a spoke shape extending radially from a rotating shaft of a rotor.

  A rotating electrical machine having a radial type rotor in which permanent magnets are embedded in spokes in a spoke shape has an excellent structure as a composite torque motor driven by magnet torque and reluctance torque. This type of rotating electrical machine is disclosed in Patent Documents 1 and 2.

  Patent Document 1 discloses a radial type rotor structure in which permanent magnets extend radially and are sandwiched between rotor cores (rotor cores). The permanent magnet is subjected to a force that tries to escape from the rotor in the radial direction due to the centrifugal force accompanying the rotation of the rotor. In order to prevent this, the permanent magnet is configured to be sandwiched between slots of the rotor core.

  FIGS. 8 and 9 show a possible structure of a rotating electrical machine that holds a permanent magnet between rotor cores. The rotating electrical machine has a stator (stator) 11 having a plurality of teeth 12 formed of a laminated iron core (core) around which a winding 13 is wound, and an outer periphery that opposes the inside of the teeth 12 with a gap therebetween. The rotor 14 is formed of an annular laminated iron core whose side is fixed to a rotating shaft (not shown), and a plurality of permanent magnets 15 are embedded in the rotor 14 so as to extend radially.

  The permanent magnet 15 has a rectangular parallelepiped shape with side surfaces 15a and 15b parallel to each other, the side surface 15a is magnetized to the south pole and the side surface 15b is magnetized to the north pole, and the radially outer end surface 15c is near the outer periphery of the rotor 14 on both sides. It is locked to the provided protrusion 14b. The permanent magnet 15 is pressed inward in the radial direction by the projections 14b, and the permanent magnet 15 is prevented from coming off due to centrifugal force. In FIG. 9, Fr is the centrifugal force acting on the permanent magnet, and Fr indicates the reaction force of the rotor core.

  However, in the above configuration, magnetic flux leakage φL through the magnetic protrusion 14b occurs on the distal end surface 14c in the radial direction of the permanent magnet 15, so that the magnetic flux flowing from the permanent magnet 15 to the stator teeth 12 decreases. Further, since the distance between the distal end surface 14c in the radial direction of the permanent magnet 15 and the tooth 12 is increased due to the protrusion 14b, the magnetic flux flowing from the permanent magnet 15 to the tooth 12 is reduced. Further, due to the protrusion 14b, the radial length 15L of the permanent magnet 15 is shortened to reduce the magnetic flux generated by the permanent magnet 15, and the size of the permanent magnet 15 is increased to generate the same magnetic flux. There is a need. Furthermore, a special shape is required to provide the protrusions 14b on the rotor 14 made of a laminated iron core, which increases costs.

  Therefore, with the structure shown in the cited document 1, it is difficult to obtain a rotating electric machine that is small and has a large magnet torque.

  Patent Document 2 discloses a rotating machine rotor that prevents the permanent magnet from coming off and allows the permanent magnet to be magnetized even after the permanent magnet and the rotor are integrated. In this rotor, a non-magnetic main body is embedded in a space from the radial front end surface of the permanent magnet to the outer peripheral surface of the rotor, and the permanent magnet and the magnetic material rotor are integrally formed by the main body.

JP-A-4-255439 JP 2001-136690 A

  However, in the rotating machine rotor of Patent Document 2, the magnetic path from the permanent magnet to the stator is long because it is filled with the main body of the nonmagnetic material between the radial front end surface of the permanent magnet and the inner peripheral surface of the stator. Therefore, the magnetic flux flowing from the permanent magnet to the stator is reduced. Further, due to the presence of the non-magnetic material, the length of the permanent magnet in the radial direction is shortened, and the generated magnetic flux of the permanent magnet is reduced. In order to generate the same magnetic flux, it is necessary to increase the size of the permanent magnet. . Furthermore, a non-magnetic body portion is provided on a rotor made of a laminated iron core, resulting in a special shape and an increase in cost.

  In view of the above-mentioned problems of the prior art, the present invention obtains a large torque with a compact configuration by bringing the permanent magnet of the rotor and the stator as close as possible, and at the same time provides a permanent magnet with a stable retaining mechanism. Is to provide.

In order to achieve the above object, the present invention provides a stator comprising an iron core around which windings are wound,
The stator is provided with a rotor having an iron core whose outer periphery is spaced apart with a gap and whose inner peripheral side is fixed to the rotating shaft,
The rotor contains a plurality of permanent magnets extending radially from the center of rotation,
The permanent magnet is formed so that an outer peripheral end surface thereof is positioned along the outer peripheral surface of the rotor, and a circumferential cross-sectional width of the permanent magnet is increased along a radial inner side of the rotor. To do.

  The iron core has a concave portion whose outer peripheral surface is deformed to the rotating shaft side at the boundary with the permanent magnet.

  The permanent magnet is formed so that a cross-sectional width in a circumferential direction changes along a radial direction of the rotor.

  The permanent magnet may be formed in a barrel shape or in a kamaboko shape so that a circumferential cross section becomes larger at a central portion in the radial direction of the rotor. The cross section may be formed in a circular arc shape.

In order to achieve the above object, the present invention provides a stator having an iron core around which windings are wound,
The stator is provided with a rotor having an iron core whose outer periphery is spaced apart with a gap and whose inner peripheral side is fixed to the rotating shaft,
The rotor contains a plurality of permanent magnets extending radially from the center of rotation,
The permanent magnet is characterized in that the outer peripheral end surface is positioned along the outer peripheral surface of the rotor, and the cross section is formed in an arc shape along a radial shape.

  Further, the iron core has a concave portion whose outer peripheral surface is deformed to the rotating shaft side at the boundary with the permanent magnet.

  Moreover, it is preferable that the said permanent magnet is formed in the circular arc from which both side surfaces each differ in a center position.

  According to the present invention, by flowing more magnetic flux from the permanent magnet to the stator, it is possible to achieve high torque with a compact configuration and to prevent the permanent magnet from coming off stably.

It is sectional drawing of the radial direction of the permanent magnet rotary electric machine of this invention Example 1. FIG. It is the principal part enlarged view of a cross section similarly. It is a principal part enlarged view of the cross section of the modification of this invention Example 1. FIG. It is explanatory drawing of a radial direction cross section and an axial direction cross section similarly. It is the detail drawing of an axial direction cross section similarly. It is sectional drawing of the radial direction of the permanent magnet rotary electric machine of this invention Example 2. FIG. It is the principal part enlarged view of a cross section similarly. It is a principal part enlarged view of the cross section of the permanent magnet rotary electric machine of this invention Example 3. FIG. It is sectional drawing of the radial direction of the permanent magnet rotary electric machine of the related art assumed. It is the principal part enlarged view of a cross section similarly.

  Embodiments of the present invention will be described below with reference to the drawings.

Example 1
First, the structure of Example 1 will be described with reference to FIGS. FIG. 1 is a radial sectional view of a permanent magnet rotating electric machine, and FIG.

  The permanent magnet rotating electric machine of the present embodiment includes a stator (stator) 1 having a 12-pole armature winding 3 and a cylindrical rotor (rotor) 2. The stator 1 is composed of a laminated iron core in which electromagnetic steel plates are laminated. Twelve teeth 1a are integrally formed in the inner circumferential direction, and a winding 3 is wound around each tooth 1a.

  The rotor 2 is composed of an annular laminated core 4 in which electromagnetic steel plates are laminated, the outer periphery thereof is opposed to the stator teeth 1a with a predetermined gap, and the inner peripheral side is fixed to a rotating shaft (described later). In the rotor 2, a permanent magnet 5 made of one ferrite magnet is embedded in one magnetic pole so as to be sandwiched between the laminated cores 4. The polarity of each permanent magnet 5 is magnetized as shown. The rotor 2 may be composed of a block-shaped iron core such as a sintered material instead of the laminated iron core.

  In the above configuration, as shown in FIG. 1, the permanent magnet rotating electric machine has a reluctance torque generated by the magnetic flux φd generated by the armature winding 3 indicated by the broken arrow and a magnet generated by the magnetic flux φq generated by the permanent magnet 5 indicated by the solid arrow. The rotor 2 is rotationally driven by the combined torque with the torque.

  The structure of the rotor 2 will be described with reference to FIG. The rotor 2 includes a laminated iron core 4 having an arcuate outer peripheral surface 4a and a permanent magnet 5 having an arcuate outer peripheral side end surface 5c. The laminated iron core 4 is provided with a slot (not shown) having the same shape as the permanent magnet 5, and each permanent magnet 5 is fixed in this slot. The permanent magnet 5 is disposed so as to extend in the radial direction in a spoke shape from the rotation center of the rotor 2.

  The permanent magnet 5 is composed of both side surfaces 5a and 5b, an outer peripheral side end surface 5c of the rotor, and an inner peripheral side end surface 5d of the rotor. The outer peripheral side end face 5c has substantially the same arc shape as the outer peripheral face (outer peripheral face of the rotor) 4a of the laminated core 4. The permanent magnet 5 is positioned such that the outer peripheral side end surface 5 c is along the outer peripheral surface (the outer peripheral surface of the rotor) 4 a of the laminated core 4.

  In FIG. 2, the outer peripheral side end surface 5 c of the permanent magnet 5 and the outer peripheral surface (the outer peripheral surface of the rotor) 4 a of the laminated iron core 4 are positioned so as to be substantially the same surface, 4 is fixed. Thus, the outer peripheral side end surface 5c and the outer peripheral surface 4a of the laminated iron core 4 (the outer peripheral surface of the rotor) 4a are made substantially the same surface, so that the outer peripheral side end surface 5c is closest to the teeth 1a of the stator. Therefore, the magnetic path from the permanent magnet 5 to the tooth 1a is shortened, and the magnetic flux flowing from the permanent magnet to the stator is not reduced. Furthermore, since the length in the radial direction of the permanent magnet 5 can be increased by extending the outer peripheral side end face 5c to the outer peripheral face 4a of the rotor, the generated magnetic flux of the permanent magnet can be increased. Further, when the same magnetic flux is generated, the axial length can be shortened, so that the rotor can be reduced in size.

  Further, if the outer peripheral side end face 5c of the permanent magnet 5 is formed in an arc shape, the end face 5c and the outer peripheral face 4a of the laminated iron core 4 can be made the same surface, and the boundary between them is formed so as not to be uneven. Rotational resistance is reduced without generating wind noise during the rotation of the rotor 2.

  FIG. 3 shows a modification of this embodiment. The permanent magnet 5 is positioned such that the outer peripheral side end surface 5c is along the outer peripheral surface 2a of the rotor, but the outer peripheral surface 4a of the laminated core 4 is on the rotational axis side from the outer peripheral surface 2a of the rotor at the boundary with the permanent magnet. It has the recessed part A which deform | transformed into. By adopting such a shape, the change in magnetic flux at the boundary between the laminated core 4 and the permanent magnet 5 is alleviated, so that torque ripple can be alleviated.

  The permanent magnet 5 has a barrel-shaped cross section in which central portions of both side surfaces 5a and 5b bulge outward. That is, the circumferential width of the permanent magnet 5 is increased from the end surface 5c toward the center in the radial direction of the rotor, and is decreased from the center to the inner peripheral end surface 5d. . Specifically, in FIG. 2, when the width of the outer peripheral side end surface 5c of the permanent magnet 5 is a, the width of the central portion of both side surfaces is b, and the width of the inner peripheral side end surface 5d is c, a <b, b > C. The expansion from the width a to b is continuously and smoothly expanded without rapidly increasing, and the reduction from the width b to the width c is continuously and smoothly reduced without rapidly decreasing.

  In this way, according to the barrel-shaped permanent magnet with the central portion bulging outward, the contact surface between the permanent magnet 5 and the laminated iron core 4 in the portion from the outer peripheral side end surface 5c to the central portion of the both side surfaces 5a, 5b. 2, the centrifugal force Fc applied to the permanent magnet 5 and the reaction force Fr of the laminated iron core 4 that counters the centrifugal force Fc act to prevent the permanent magnet 5 from coming off. Since the cross-sectional area of the permanent magnet continuously and smoothly expands from the end surface 5c to the central portion as described above, the action point is distributed over the entire contact surface between the permanent magnet 5 and the laminated iron core 4. . Since the above-mentioned action points are distributed over the length of about half the length of the permanent magnet 5 from the end face 5c to the central portion, the force acting on each action point becomes considerably small.

  Therefore, since the permanent magnet 5 and the laminated iron core 4 are not subjected to local force, the permanent magnet 5 and the laminated iron core 4 are not damaged each other, and the permanent magnet on which the centrifugal force acts is provided with a stable retaining for a long time. Can do.

  Further, the barrel-shaped permanent magnet has a width that is narrower from the center toward the outer peripheral side end face 5c and can increase the width W1 on the outer peripheral side of the laminated iron core 4, so that the magnetic flux φq is increased. However, magnetic reluctance torque can be obtained without causing magnetic saturation. Furthermore, since the width is narrower from the center part of the permanent magnet to the inner peripheral side end face 5d and the inner peripheral side width W2 of the laminated core 4 can be made larger, saturation of the passing magnetic flux hardly occurs and the rotor is assembled. When the permanent magnet is magnetized in the above state, the magnetization efficiency is improved.

  FIG. 4 is an explanatory diagram of a radial cross section and an axial cross section, FIG. 4 (b) shows a cross section along line BB in FIG. 4 (a), the upper half shows a cross section of the permanent magnet 5, The lower half shows a cross section of the laminated core 4.

  FIG. 5 shows details of the axial cross section, 6 is a side plate that supports both ends of the laminated core 4 of the rotor 2, and 7 is tightened to the laminated core 4 through the side plate 6 through the side plate 6 and the laminated core 4. A bolt 8 is a rotating shaft on which the inner peripheral side of the rotor 2 is fixed via the side plate 6. 1 and 2, the bolt 7 is not shown.

(Example 2)
Next, the structure of the second embodiment will be described with reference to FIGS. FIG. 6 is a radial cross-sectional view of the permanent magnet rotating electric machine, and FIG. 7 is an enlarged view of a main part of the cross-section.

  Example 2 is the same as Example 1 in that the outer peripheral side end surface 5c of the permanent magnet 5 and the outer peripheral surface (the outer peripheral surface of the rotor) 4a are the same surface. The difference from the first embodiment is that one of the both side surfaces 5a and 5b of the permanent magnet 5 bulges outward at the central portion, and the cross section is formed in a crumpled shape (shape). In the figure, the side surface 5a is formed in a straight line (plane), and the side surface 5b is formed in a swelled shape. In FIG. 7, when the width of the outer peripheral side end face 5c of the permanent magnet 5 is a, the width of the central part is b, and the width of the inner peripheral side end face 5d is c, the relationship is a <b, b> c. Is done. And the expansion of the side surface 5b from the width a to b is continuously and smoothly expanded without abrupt expansion, and the reduction of the side surface 5b from the width b to the width c is also continuously smooth without abrupt reduction. It has shrunk to.

  In the second embodiment, the centrifugal force Fc applied to the permanent magnet 5 and the reaction force Fr of the laminated core 4 that opposes the centrifugal force Fc act on the portion from the outer peripheral side end surface 5c of the permanent magnet 5 to the central portion of one side surface 5b. To do. And since the cross-sectional width of a permanent magnet is continuously and smoothly enlarged from the end surface 5c to the center part similarly to Example 1, the said action point is continuously on the part from the said end surface 5c to the center part. The force acting on each action point is considerably reduced.

  Therefore, since the permanent magnet 5 and the laminated iron core 4 are not subjected to local force, the permanent magnet 5 and the laminated iron core 4 are not damaged each other, and the permanent magnet on which the centrifugal force acts is provided with a stable retaining for a long time. Can do.

  In the second embodiment, since the side surface 5a is a straight line (plane) and only the side surface 5b is formed in a bulging shape, the centrifugal force Fc applied to the permanent magnet 5 and the reaction force Fr of the laminated iron core 4 that counters this are obtained. Although it works only on the side surface 5b, the processability of the straight line (plane) forming portion of the side surface 5a is good, so that the processing cost can be reduced.

  Further, similarly to the first embodiment, according to the permanent magnet having a cone-shaped shape, the width of the outer peripheral side end face 5c is narrower than the central portion, and the width W1 on the outer peripheral side of the laminated core 4 can be increased. Even when the magnetic flux φq is increased, magnetic saturation does not occur and a large reluctance torque can be obtained. Furthermore, since the width is narrower from the center part of the permanent magnet to the inner peripheral side end face 5d and the inner peripheral side width W2 of the laminated core 4 can be made larger, saturation of the passing magnetic flux hardly occurs and the rotor is assembled. When the permanent magnet is magnetized in the above state, the magnetization efficiency is improved.

(Example 3)
Next, the structure of Example 3 will be described with reference to FIG. FIG. 8 is an enlarged view of a main part of a cross section of the permanent magnet rotating electric machine.

  The configuration of the third embodiment is the same as the first and second embodiments in that the outer peripheral side end surface 5c of the permanent magnet 5 and the outer peripheral surface (the outer peripheral surface of the rotor) 4a are positioned on the same plane. A different point from the said Example is a point in which the center part of both the side surfaces 5a and 5b of the permanent magnet 5 both curves, and the cross section is formed in circular arc shape. In FIG. 8, the central portion of the side surface 5a is concave and the central portion of the side surface 5b is deformed into a convex shape. These deformations are formed so as to continuously and smoothly change.

  In FIG. 8, the circumferential width of the permanent magnet 5 is indicated by d. The width d is set to be larger than the widths of both ends (the width a of the outer peripheral side end surface 5c and the width c of the inner peripheral side end surface 5d) at the center. Alternatively, the entire cross-sectional width from the outer peripheral side end face 5c to the inner peripheral side end face 5d may be set to the same width.

  In the arc-shaped permanent magnet having a curved central portion according to the third embodiment, the centrifugal force Fc applied to the permanent magnet 5 and the reaction force Fr of the laminated iron core 4 that opposes the centrifugal force Fc are applied to the permanent magnet 5 from the outer peripheral side end face 5c. It acts on the sloped part from the concave top part to the inner peripheral side end face 5d of the central part of the other side face 5a.

  And since each said inclination part is changing continuously smoothly, the said action point is the contact surface of the inclination part of the side surface 5a of the permanent magnet 5, and the laminated iron core 4, and the inclination of the side surface 5b of the permanent magnet 5. Dispersed on the contact surface between the portion and the laminated core 4. In this way, the operating point is distributed between about half the length of the permanent magnet 5 on one side of the permanent magnet 5 and about half the length of the permanent magnet 5 on the other side of the permanent magnet 5. The force acting on the point of action is much smaller.

  Therefore, since the permanent magnet 5 and the laminated iron core 4 are not subjected to local force, the permanent magnet 5 and the laminated iron core 4 are not damaged each other, and the permanent magnet on which the centrifugal force acts is provided with a stable retaining for a long time. Can do.

  When the side surfaces 5a and 5b are set to have the same curvature radius, the permanent magnet 5 may move in the slot of the laminated core 4 due to centrifugal force. In order to prevent this, when the permanent magnet 5 is formed in an arc shape, it may be formed so that the center positions of the respective arcs of both side surfaces 5a and 5b are different. That is, as shown in FIG. 8, the center position of the arc of radius R1 of the side surface 5a of the permanent magnet 5 is different from the center position of the arc of radius R2 of the side surface 5b. The radii R1 and R2 may be the same or different.

  In this way, if both side surfaces of one permanent magnet 5 are formed in circular arcs having different center positions, the movement trajectories of both side surfaces are different, so that the permanent magnet 5 cannot move and can be prevented from coming off.

  In addition, since both side surfaces of the permanent magnet 5 are formed of circular arcs, they are smoothly deformed, so that the action points of the centrifugal force Fc applied to the permanent magnet 5 and the reaction force Fr of the laminated core 4 can be dispersed. . Therefore, no local force is applied to the permanent magnet 5 and the laminated iron core 4, and the permanent magnets are not damaged from each other. Can do.

  As described above, according to the permanent magnet rotating electrical machine of each embodiment, a large magnetic flux is generated from the permanent magnet to the stator by bringing the permanent magnet of the rotor and the stator as close as possible to each other and by providing a stable retaining structure for the permanent magnet. As a result, a large torque can be obtained with a compact configuration, a stable permanent magnet can be prevented from coming off, and high-performance operation can be safely continued over a long period of time.

  DESCRIPTION OF SYMBOLS 1 ... Stator, 1a ... Teeth, 2 ... Rotor, 2a ... Outer peripheral surface of rotor, 3 ... Winding, armature winding, 4 ... Iron core, laminated iron core, 4a ... Outer circumferential surface of laminated iron core, 4 ... Permanent magnet, 5a, 5b Side surface of permanent magnet, 5c ... Outer peripheral end surface of permanent magnet, 5d ... Inner peripheral end surface of permanent magnet, 8 ... Rotating shaft, A ... Recess, a, b, c ... Section width of permanent magnet, Fc ... Centrifugal force applied to the permanent magnet, Fr: reaction force of the laminated core 4, R1, R2: radius of curvature of the permanent magnet, W1: width of the laminated core on the outer peripheral side, W2: width of the laminated core on the inner peripheral side.

Claims (9)

A stator made of an iron core wound with windings;
The stator is provided with a rotor having an iron core whose outer periphery is spaced apart with a gap and whose inner peripheral side is fixed to the rotating shaft,
The rotor contains a plurality of permanent magnets extending radially from the center of rotation,
The permanent magnet is formed so that an outer peripheral end surface thereof is positioned along the outer peripheral surface of the rotor, and a circumferential cross-sectional width of the permanent magnet is increased along a radial inner side of the rotor. Permanent magnet rotating electric machine. In the permanent magnet rotating electric machine according to claim 1,
The iron core has a concave portion whose outer peripheral surface is deformed toward the rotating shaft at the boundary with the permanent magnet. In the permanent magnet rotating electric machine according to claim 1 or 2,
The permanent magnet rotating electric machine, wherein the permanent magnet is formed so that a cross-sectional width in a circumferential direction changes along a radial direction of a rotor. In the permanent magnet rotating electric machine according to any one of claims 1 to 3,
The permanent magnet rotating electric machine is characterized in that a cross section of the permanent magnet is formed in a barrel shape so that a cross section in a circumferential direction becomes large at a central portion in a radial direction of a rotor. In the permanent magnet rotating electric machine according to any one of claims 1 to 3,
The permanent magnet rotating electric machine is characterized in that the cross section of the permanent magnet is formed in a scallop shape so that the cross section in the circumferential direction becomes large at a central portion in the radial direction of the rotor. In the permanent magnet rotating electric machine according to any one of claims 1 to 3,
The permanent magnet rotating electric machine is characterized in that the permanent magnet has a circular cross section along a radial shape. A stator having an iron core wound with windings;
The stator is provided with a rotor having an iron core whose outer periphery is spaced apart with a gap and whose inner peripheral side is fixed to the rotating shaft,
The rotor contains a plurality of permanent magnets extending radially from the center of rotation,
The permanent magnet rotating electrical machine is characterized in that the permanent magnet is positioned such that an outer peripheral end surface thereof is along the outer peripheral surface of the rotor, and a cross section is formed in an arc shape along a radial shape. In the permanent magnet rotating electric machine according to claim 7,
The iron core has a concave portion whose outer peripheral surface is deformed toward the rotating shaft at the boundary with the permanent magnet. In the permanent magnet rotating electric machine according to claim 7 or 8,
The permanent magnet rotating electric machine is characterized in that both side surfaces are formed in circular arcs having different center positions.

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