JP2010183684A - Permanent magnet type rotor for rotary machine - Google Patents

Abstract

An object of the present invention is to obtain a highly efficient permanent magnet type rotor having a high magnetic force generated on the outer peripheral surface of the rotor.
A permanent magnet type rotor includes a rotary shaft, a plurality of substantially fan-shaped iron core pieces made of a ferromagnetic material and arranged on the outer peripheral side of the rotary shaft at equal intervals in the circumferential direction, and an iron core. It consists of a plurality of permanent magnet pieces 4 arranged between the pieces 30 so as to alternate with the core pieces 30 in the circumferential direction. The permanent magnet pieces 4 are arranged so that the polarities of the surfaces facing the permanent magnet pieces 4 arranged adjacent to each other are the same, and the orientation direction line of the permanent magnet pieces 4 is the same as that of the permanent magnet type rotor 1. The curve is convex in the direction of the rotation axis.
[Selection] Figure 1

Description

  The present invention relates to a permanent magnet rotor for a rotating machine such as a permanent magnet field motor or a generator.

A conventional permanent magnet type rotor is a magnetic pole piece formed by laminating laminated pieces of fan-shaped steel plates to a predetermined thickness, and a plurality of magnetic pole pieces are arranged radially, and a cross section is formed between flat portions of the magnetic pole pieces. A cylindrical rotor core is formed by fixing a rectangular permanent magnet with an adhesive (see, for example, Patent Document 1).
A conventional permanent magnet type rotor has a rotor core connected to a rotating shaft and a plurality of permanent magnets fixed at equal intervals in the circumferential direction of the rotor core (for example, refer to Patent Document 2).

Japanese Patent Laid-Open No. 3-36945 ([Prior Art], FIG. 10 etc.) JP 2008-29078 A (paragraph [0014], FIG. 1 etc.)

In a conventional permanent magnet type rotor, a plate-like magnet that is magnetically oriented in a uniaxial direction is generally used as a permanent magnet disposed between iron cores serving as magnetic poles. FIG. 19 is a plan view of a conventional general permanent magnet type rotor 60, in which a plurality of plate-like permanent magnets 62 and a plurality of fan-shaped iron cores 63 are alternately arranged on the outer peripheral side of the rotating shaft 61. 62 and the iron core 63 are bonded together. In the figure, solid arrows indicate the magnetic orientation direction inside the permanent magnet 62, and dotted arrows indicate the flow of magnetic flux generated from the permanent magnet 62. As shown in the figure, the permanent magnets 62 magnetically oriented in the uniaxial direction are arranged between the iron cores 63 so that the same poles are opposed to each other, and the magnetic flux generated from the permanent magnets 62 rotates in an opposed manner in the iron core 63. Magnetic force is generated on the outer peripheral surface of the child 60. However, in such a permanent magnet 62 magnetically oriented in the uniaxial direction, there is a problem that the magnetic flux flows not only in the outer peripheral direction but also in the direction of the rotating shaft 61, and the energy of the permanent magnet 62 cannot be fully exhibited. .
The present invention has been made to solve the above-described problems, and an object thereof is to obtain a highly efficient permanent magnet type rotor having a high magnetic force generated on the outer peripheral surface of the rotor.

  A permanent magnet type rotor according to the present invention includes a rotating shaft, a plurality of substantially fan-shaped iron core pieces made of a ferromagnetic material and arranged at equal intervals in the circumferential direction on the outer peripheral side of the rotating shaft, and an iron core between the iron core pieces. It consists of a piece and several permanent magnet pieces arrange | positioned so that it may alternate in the circumferential direction. The permanent magnet pieces are arranged so that the polarities of the faces facing the permanent magnet pieces arranged adjacent to each other in the circumferential direction are the same, and the orientation direction line of the permanent magnet pieces is the rotation axis of the permanent magnet type rotor. The curve is convex in the direction.

  According to the permanent magnet type rotor of the present invention, the orientation direction line of the permanent magnet piece is a convex curve in the rotation axis direction of the permanent magnet type rotor, and therefore flows in the rotation axis direction of the permanent magnet type rotor. Magnetic flux can be reduced, and the magnetic force generated on the outer peripheral surface of the permanent magnet type rotor can be increased. Therefore, torque improvement and high efficiency of the rotating machine can be realized, and the volume of the permanent magnet piece necessary for generating the same magnetic force can be reduced, so that the rotating machine can be reduced in size.

It is a top view of the permanent magnet type | mold rotor in Embodiment 1 of this invention. It is the figure which expanded partially the top view of the permanent magnet type | mold rotor in Embodiment 1 of this invention. It is a figure for demonstrating the dimensional relationship of the permanent magnet type | mold rotor in Embodiment 1 of this invention. It is a figure which shows the permanent magnet type | mold rotor of another example in Embodiment 1 of this invention. It is a figure for demonstrating the manufacturing method of the permanent magnet type | mold rotor in Embodiment 1 of this invention. It is a figure which shows the permanent magnet type | mold rotor of another example in Embodiment 1 of this invention. It is a figure for demonstrating the manufacturing method of the permanent magnet piece used for the permanent magnet type | mold rotor in Embodiment 1 of this invention. It is a figure for demonstrating another example of the manufacturing method of the permanent magnet piece used for the permanent magnet type rotor in Embodiment 1 of this invention. It is a conceptual diagram which shows the mode of the magnetic flux which generate | occur | produces from the permanent magnet piece each used for the permanent magnet type | mold rotor in Embodiment 1 of this invention, and the permanent magnet type | mold rotor of the comparative example 1, respectively. The peak value of the magnetic flux density of the permanent magnet piece used in each of the permanent magnet type rotor in the first embodiment of the present invention, the permanent magnet type rotor in the comparative example 1, and the permanent magnet type rotor in the comparative example 2 It is a figure which shows the result of having measured. The concept which shows the cross-sectional shape of the permanent magnet piece used for the permanent magnet type | mold rotor in Embodiment 1 of this invention, the permanent magnet type | mold rotor of the comparative example 1, and the permanent magnet type | mold rotor of the comparative example 2, respectively. FIG. A magnetic field representing the leakage flux on the rotation axis side of the permanent magnet piece of the permanent magnet piece of the permanent magnet type rotor of Embodiment 1 of the present invention and the leakage flux on the rotation axis side of the permanent magnet piece of the permanent magnet type rotor of Comparative Example 1 It is an analysis result. It is a conceptual diagram of the permanent magnet type | mold rotor in Embodiment 2 of this invention. It is detail drawing of the permanent magnet piece used for the permanent magnet type | mold rotor in Embodiment 2 of this invention. It is detail drawing of the permanent magnet piece used for the permanent magnet type | mold rotor in the comparative example of Embodiment 2 of this invention. It is detail drawing of the permanent magnet piece of another example used for the permanent magnet type | mold rotor in Embodiment 2 of this invention. It is a conceptual diagram which shows the permanent magnet type | mold rotor of another example in Embodiment 2 of this invention. It is explanatory drawing explaining the manufacturing method of the permanent magnet piece used for the permanent magnet type rotor of another example in Embodiment 2 of this invention. It is a top view of the conventional common permanent magnet type | mold rotor.

Embodiment 1 FIG.
1 is a plan view of a permanent magnet type rotor according to Embodiment 1 of the present invention, and FIG. 2 is a partially enlarged view of the permanent magnet type rotor (hereinafter referred to as a rotor) of FIG.
As shown in FIG. 1, the rotor 1 according to the first embodiment is a rotor having six poles, and includes a rotating shaft 2, an iron core 3, and a permanent magnet piece 4. The iron core 3 is composed of a plurality of iron core pieces 30, and each iron core piece 30 is formed by laminating electromagnetic steel sheets in the axial direction and connecting the steel sheets by caulking or the like. The cross-sectional shape of the iron core piece 30 is a substantially fan shape in which the center side of the fan shape is cut off. It is arranged on the side at equal intervals in the circumferential direction.

  Six permanent magnet pieces 4 made of neodymium sintered magnets are arranged between the iron core pieces 30 so as to alternate with the iron core pieces 30 in the circumferential direction, and are adjacent to each other in the circumferential direction. It arrange | positions so that the polarity of the surface which opposes may become the same polarity. That is, the polarities of the permanent magnet pieces 4 on both sides of each iron core piece 30 are the same. For this reason, the outer peripheral surface of the core piece 30 sandwiched between the N poles of the permanent magnet piece 4 is magnetized to the N pole, and the outer peripheral surface of the iron core piece 30 sandwiched between the S poles of the permanent magnet piece 4 is magnetized to the S pole. The pieces 30 are magnetized alternately to the north and south poles in the circumferential direction. 1 and 2, the arrow inside the permanent magnet piece 4 indicates the direction of the easy magnetization axis (direction in which magnetization is easy), and the easy magnetization axis changes continuously in the direction of the rotation axis 2 of the rotor 1 as shown in the figure. It is formed to have a convex curve. The direction of the easy magnetization axis is aligned by the magnetic field orientation at the time of forming the permanent magnet, and the direction line of the easy magnetization axis is hereinafter referred to as the orientation direction line. The cross-sectional shape of the permanent magnet piece 4 is a substantially fan shape in which the center side of the fan shape is cut off by an arc concentric with the fan shape, and the substantially fan-shaped outer peripheral arc of the permanent magnet piece 4 is in the direction of the rotation axis 2 of the rotor 1. It is arranged to face. In the first embodiment, the orientation direction line of the permanent magnet piece 4 has an arc shape concentric with the fan center of the permanent magnet piece 4.

  A gap between the rotary shaft 2 and the core piece 30 and the permanent magnet 4 is filled with a resin 5 such as PPC (polyphenylene sulfide), nylon, epoxy, etc., and the rotary shaft 2, the plurality of core pieces 30 and the plurality of permanent pieces. The magnet piece 4 is fixed integrally. A protrusion 31 is provided on the surface of the core piece 30 facing the rotating shaft 2, thereby increasing the fixing strength of the rotor 1. Note that the surface of the iron core piece 30 facing the rotating shaft 2 may be provided with, for example, a concave notch instead of the protrusion 31, and the fixing strength of the rotor 1 can be similarly increased.

In the first embodiment, a neodymium sintered magnet, which is a rare earth sintered magnet, is used as the permanent magnet piece 4. However, the present invention is not limited to this, and a ferrite magnet, a plastic magnet, or the like may be used. .
Further, the iron core piece 30 is not limited to one formed by laminating electromagnetic steel plates, and for example, a machined piece of a massive ferromagnetic member may be used, or a powder iron core may be used.
Further, the number of poles of the rotor is not limited to 6 poles, and can be applied to rotors of 4, 6, 8, 10, 12 poles, etc. The effect of the direction of the alignment direction line can be exhibited.

FIG. 3 is an explanatory diagram for explaining the dimensions of the rotor 1 according to the first embodiment. Based on this, the optimum dimensional relationship of each element constituting the rotor 1 will be described.
As shown in FIG. 3, in the permanent magnet piece 4, the length of the arc 41 positioned on the rotating shaft 2 side is larger than the arc 40 positioned on the outer peripheral side of the rotor 1, and The arc centers of the two arcs 40 and 41 coincide. Here, the number of poles of the rotor 1 is n, the outer radius of the rotor 1 (the virtual circular radius of the outermost peripheral surface of the rotor 1) is Ro, and the fan center of the permanent magnet piece 4 from the center of the rotor 1 ( The distance to the arc center) is R, the substantially fan-shaped opening angle (center angle) of the permanent magnet piece 4 is 2θ, the arc radius of the arc 41 located on the rotating shaft 2 side of the permanent magnet piece 4 is Rmo, and the permanent magnet piece Assuming that the arc radius of the arc 40 positioned on the outer peripheral side of the No. 4 rotor 1 is Rmi (where Rmo> Rmi), the rotor 1 of the first embodiment is formed when all the following conditions are satisfied. This is the optimum dimension for each component.
2π / θ> 2 (1)
R> Ro / cos (π / n) and Rmi> (R−Ro) / cos θ (2)
R> Ro / cos (π / n) and Rmo <Rsin (π / n) / cos (π / 2−π / n−θ) (3)
If the condition (1) is not satisfied, the opening angle of the substantially fan-shaped permanent magnet piece 4 is 360 ° or more, and the permanent magnet piece cannot be configured. Further, when the above condition (2) is not satisfied, that is, when Rmi is a value equal to or smaller than (R−Ro) / cos θ, the permanent magnet piece 4 protrudes from the outer peripheral surface of the rotor 1. The air gap (air gap) with the stator arranged on the outer peripheral side of 1 becomes wider, resulting in problems such as increased magnetic resistance. When the above condition (3) is not satisfied, that is, when Rmo has a value equal to or greater than Rsin (π / n) / cos (π / 2−π / n−θ), the permanent magnet pieces 4 are adjacent to each other. The arranged permanent magnet piece 4 and the rotating shaft of the rotor 1 come into contact with each other, and the rotor 1 cannot be configured.

  FIG. 4 is a partially enlarged view of another example of the rotor 10a according to the first embodiment. As shown in FIG. 4, the arc of the iron core piece 30a forming the outermost peripheral surface of the rotor 10a does not necessarily need to overlap with a virtual circle (indicated by a dotted line in the figure) of the outermost peripheral surface of the rotor 10a. For example, it may be an arc having a diameter smaller than a virtual circle on the outermost peripheral surface of the rotor 10a, and the shape can be changed as necessary.

FIG. 5 is an explanatory diagram for explaining a method of manufacturing the rotor 1 according to the first embodiment. A method of manufacturing the rotor 1 will be described with reference to FIG.
First, as shown in FIG. 5A, a substantially fan-shaped iron core piece 30 and a substantially fan-shaped permanent magnet piece on the outer peripheral side of the rotating shaft 2, for example, in a mold for injection molding (not shown). 4 are arranged with a gap so as to alternate with each other in the circumferential direction.
Next, as shown in FIG. 5B, the core piece 30 and the permanent magnet piece 4 are brought into contact with each other by pushing the core piece 30 from the outer peripheral side of the rotor 1 toward the center of the rotor 1. At this time, it is desirable that the virtual circle center of the outermost peripheral surface of the rotor 1 formed by the plurality of iron core pieces 30 and the rotation center of the rotary shaft 2 be the same.
Next, as shown in FIG. 5C, a resin 5 such as PPS is injection-molded from the axial direction into a space formed by the rotating shaft 2, the iron core piece 30, and the permanent magnet piece 4, and the rotating shaft 2 and the iron core are then molded. The piece 30 and the permanent magnet piece 4 are fixed so as to be integrated.
The permanent magnet piece 4 is magnetized (not shown) by applying a magnetic field for alternately forming an N pole and an S pole in the circumferential direction from the outer peripheral side of the rotor 1 manufactured in this way. The rotor 1 of the form 1 is completed. Due to the magnetization of the permanent magnet piece 4, the iron core piece 30 is attracted to the permanent magnet piece 4 and the fixing strength of the rotor 1 is increased. Further, by arranging the substantially fan-shaped outer peripheral arc of the permanent magnet piece 4 so as to face the direction of the rotation axis 2 of the rotor 1, the permanent magnet piece 4 is tapered in the radial direction, and the core piece 30 is prevented from coming off. Therefore, the permanent magnet piece 4 can be prevented from coming off in the outer circumferential direction without adhering between the adjacent surfaces of the iron core piece 30 and the permanent magnet piece 4.
The permanent magnet piece 4 and the core piece 30 can be more firmly fixed by providing a slight gap between the permanent magnet piece 4 and the adjacent core pieces 30 and filling the gap with resin. .
The fixing method is not limited to the resin 5, and for example, an annular fixing plate or the like may be provided at both ends in the axial direction, and the core piece 30 may be sandwiched and fixed by rivets or the like.

The configuration of the rotor 1 according to the first embodiment is not limited to that described above. For example, iron core pieces may be connected in the circumferential direction at a part of the axial direction. Such a rotor may be used as the first embodiment. Another example is shown in FIG.
FIG. 6 is a perspective view showing another example of the rotor according to the first embodiment. 6A is a perspective view showing another example of the rotor 1a, FIG. 6B is a perspective view of an iron core plate 3b constituting the rotor 1a, and FIG. 6C constitutes the rotor 1a. It is a perspective view of the iron core board 3c. The other configuration of the rotor 1a other than the iron core piece is the same as that of the first embodiment described above, and the same parts are denoted by the same reference numerals and description thereof is omitted.
As shown in FIG. 6, the iron core piece 3a of the rotor 1a is formed by laminating a substantially fan-shaped iron core plate 3b made of electromagnetic steel plates and an annular iron core plate 3c and connecting the steel plates with caulking or rivets. Is done. A groove 3d for inserting the permanent magnet piece 4 is provided in the annular iron core plate 3c, and the permanent magnet piece 4 can be inserted from the axial direction of the iron core piece 3a.
In this way, by sandwiching the annular core plate 3c in a part in the axial direction, the core piece 3a is annularly coupled in a part in the axial direction, and the core piece 3a can be handled integrally. Therefore, compared with the case where the core pieces are individually separated, it is not necessary to handle and align the core pieces separately, thereby improving productivity.

FIG. 7 is an explanatory diagram for explaining a method of manufacturing the permanent magnet piece 4 of the rotor 1 in the first embodiment. The manufacturing method of the permanent magnet piece 4 is demonstrated with reference to FIG.
A die 6 as shown in FIG. 7A is used for manufacturing the permanent magnet piece 4. The mold 6 includes a ring-shaped cavity 63 formed by a die 60 made of a ferromagnetic member or a nonmagnetic member, a lower punch 61 made of a nonmagnetic member, and a core rod 62. The core rod 62 is composed of an outer shell made of a cylinder such as metal or ceramic, and an electric conductor that extends in the axial direction. The electric conductor is for flowing current in the axial direction of the core rod 62, and is made of a conducting wire (copper wire insulated from each other) or a copper lump extending in the axial direction. The space between the outer shell and the electric conductor is molded with a resin such as epoxy.

First, as shown in FIG. 7A, the magnetic powder 64 is filled into the ring-shaped cavity 63 of the mold 6.
Next, as shown in FIG. 7B, in order to orient the magnetic powder 64 in the circumferential direction of the ring-shaped cavity 63, an electric current is instantaneously passed through the electrical conductor built in the core rod 62. By passing a current through the electric conductor, a magnetic field is generated around the core rod 62, and the magnetic powder 64 in the cavity 63 can be oriented in the circumferential direction. The arrow in FIG. 7B indicates the direction of current, and the mark drawn on the magnetic powder 64 indicates the direction of the magnetic field. Note that the current to be generated may flow instantaneously once or may flow multiple times. Also, the direction of current is not limited to the direction in the figure. Further, not only a direct current but also an alternating current in which the direction of current is alternately reversed may be used, and an alternating current in which the magnitude of the current is attenuated with time may be used.
Next, as shown in FIG. 7C, the upper punch 65 is lowered to press the oriented magnetic powder 64 in the axial direction to form a ring-shaped green compact 66.
Next, as shown in FIG. 7D, the lower punch 61 is raised to take out the green compact 66 from the mold, and then heat treated to sinter the green compact 66 to form a ring-shaped permanent magnet 67. .
Next, as shown in FIG. 7 (E), the inner and outer circumferences and end faces of the sintered ring-shaped permanent magnet 67 are finished by machining, and as shown in FIG. Permanent magnet pieces 4 are formed by equally dividing radially from the central axis. FIG. 7 (G) is an enlarged view of the permanent magnet piece 4, and the arrows in FIG. 7 (G) indicate alignment direction lines.

As shown in FIG. 7 (G), the permanent magnet piece 4 formed as a split piece of the ring-shaped permanent magnet 67 has a constant cross-sectional shape in the axial direction, and the cross-sectional shape of the permanent magnet piece 4 is the fan-shaped center side. It is a substantially fan shape cut off by concentric arcs. The orientation direction line of the permanent magnet piece 4 is a curve along a substantially fan-shaped arc, that is, an arc-shaped curve concentric with a substantially fan-shaped fan center (center of the ring-shaped permanent magnet 67).
For example, when the number of poles of the rotor 1 is 6 and the opening angle of the substantially fan-shaped permanent magnet piece 4 to be used is 20 degrees, three of the rotor 1 from one ring-shaped permanent magnet 67 Eighteen permanent magnet pieces 4 that are minutes can be cut out.
Not only can the single ring-shaped permanent magnet 67 be equally divided to cut out the permanent magnet pieces 4 having the same opening angle, but also permanent magnet pieces having different opening angles can be cut out from the single ring-shaped permanent magnet 67. Well, this makes it possible to produce permanent magnet pieces for use in rotors of multiple poles or sizes.

Here, in general, the shrinkage rate when sintering a permanent magnet differs between a direction parallel to the orientation direction of the permanent magnet piece and a direction perpendicular to the orientation direction. The vertical direction does not shrink much. Because of these characteristics, if the shape of a permanent magnet having a concentric arc-shaped orientation direction before sintering is, for example, a permanent magnet having a rectangular cross section, the width dimension increases as the curvature in the orientation direction increases after sintering. Will be distorted into a trapezoidal cross section. If a permanent magnet piece such as the permanent magnet piece 4 of the first embodiment is cut out from such a substantially trapezoidal permanent magnet, the machining allowance at the time of machining becomes very large.
On the other hand, if a ring-shaped permanent magnet magnetically oriented in the circumferential direction is formed as in the manufacturing method of the first embodiment, the ring shape can be maintained after sintering. Occurrence of shape distortion at the time can be suppressed. Then, if the permanent magnet piece 4 is formed by dividing the sintered ring-shaped permanent magnet 67, the low-cost permanent magnet piece 4 with a small cutting allowance and a good material yield can be obtained.

  Although the ring-shaped permanent magnet 67 is divided radially from the central axis of the ring-shaped permanent magnet 67, the dividing method is not necessarily limited to this. For example, a permanent magnet piece having a desired shape centering on a position different from the center axis of the ring-shaped permanent magnet 67 may be cut out as necessary. However, in the case of such a dividing method, all of the ring-shaped permanent magnets 67 cannot be used as permanent magnet pieces and unnecessary portions are generated. Therefore, considering the yield, the ring-shaped permanent magnets 67 are arranged radially from the central axis. It is desirable to divide into two.

  FIG. 8 is an explanatory view showing another example of the method for manufacturing the permanent magnet piece 4 of the rotor 1 according to the first embodiment. As shown in FIG. 8, as another example of the method for manufacturing the permanent magnet piece 4, a long-axis ring-shaped permanent magnet 67a that is long in the axial direction may be formed. Thereby, the long-axis ring-shaped permanent magnet 67a can be divided into a plurality of ring-shaped permanent magnets 67 in the axial direction, and more permanent magnet pieces 4 can be manufactured by one molding.

FIG. 9A is a conceptual diagram showing a state of magnetic flux generated from the permanent magnet piece 4 in the rotor 1 of the first embodiment using the permanent magnet piece 4 obtained by the above manufacturing method. For comparison, FIG. 9B is a conceptual diagram of the state of magnetic flux in a rotor 1b (hereinafter referred to as a rotor of Comparative Example 1) using a plate-like permanent magnet piece 4b whose orientation direction is uniaxial. Show. In FIG. 9, the arrows in the permanent magnet pieces 4 and 4b indicate the orientation direction lines of the permanent magnet pieces 4 and 4b, the arrows passing through the iron core pieces 30 and 30b indicate the magnetic flux, and the dotted line in FIG. Arrows indicate leakage flux.
As shown in the figure, in the first embodiment, since the orientation direction line of the permanent magnet piece 4 is a circular arc that is convex in the direction of the rotation axis (rotation center) of the rotor 1, most of the generated magnetic flux is the rotor. 1 is flowing toward the outer circumferential direction. On the other hand, in the rotor 1b of the comparative example 1, since the orientation direction line of the permanent magnet piece 4b is uniaxial, the generated magnetic flux flows in the outer peripheral direction and also flows in the direction of the rotation axis (rotation center) and leaks magnetic flux. It has become. Thus, by making the orientation direction line of the permanent magnet piece convex in the direction of the rotation axis of the rotor, the leakage magnetic flux in the direction of the rotation axis is reduced, and the magnetic flux density on the outer peripheral surface of the rotor is increased. be able to.
If the orientation direction line is orthogonal to the two sides facing the circumferential direction of the permanent magnet piece 4 as in the permanent magnet piece 4 of the first embodiment, the magnetic flux generated from the permanent magnet piece 4 Flows so as to be orthogonal to the tangent to the core piece 30, so that a stronger magnetic force can be generated on the outer peripheral surface of the rotor 1.

Moreover, since the comparative example 1 uses the plate-shaped permanent magnet piece 4b, it is necessary to provide the protrusion 30c for retaining the permanent magnet piece 4b on the iron core piece 30b. When the protrusion 30c exists, a part of the magnetic flux flowing from the permanent magnet piece 4b to the outer peripheral side of the rotor 1b through the iron core piece 30b leaks to the protrusion 30c adjacent to the circumferential direction, and the outer peripheral surface of the rotor 1b. The magnetic flux density generated at the end will decrease. Therefore, by making the cross-sectional shape of the permanent magnet piece substantially fan-shaped like the permanent magnet piece 4 of the first embodiment, the permanent magnet piece 4 has a taper shape in the radial direction and has an effect as a retainer. At the same time, the leakage magnetic flux on the rotor outer peripheral side can be reduced, and the magnetic flux density on the outer peripheral surface can be increased.
Even when the substantially fan-shaped permanent magnet piece 4 according to the first embodiment is used, the iron core piece 30 may be provided with a protrusion such as the protrusion 30c of Comparative Example 1 for positioning the permanent magnet piece 4. The effect of increasing the magnetic flux density on the outer peripheral surface can be obtained when the orientation direction line of the permanent magnet piece 4 is arcuate.

  FIG. 10 shows the result of measuring the peak value of the magnetic flux density generated on the outer peripheral surface of the rotor 1 of the first embodiment using the permanent magnet piece 4 obtained by the above manufacturing method. For comparison, the rotor 1b of Comparative Example 1 using a plate-shaped permanent magnet piece 4b whose orientation direction is uniaxial and the permanent magnet piece 4c whose orientation direction is uniaxial and substantially fan-shaped are used. The peak value of the magnetic flux density generated on the outer peripheral surface of the rotor 1c (hereinafter referred to as the rotor of Comparative Example 2) was also measured. The results are also shown in FIG. FIG. 11 is a conceptual diagram showing the cross-sectional shapes of the permanent magnet pieces 4, 4b, 4c used in the rotors of the first embodiment, comparative example 1, and comparative example 2. For the permanent magnet pieces 4 and 4c of the first embodiment and the comparative example 2, three types having an opening angle 2θ of 20 degrees, 30 degrees, and 40 degrees with a substantially sectional fan shape are prepared. For each opening angle, the volume of the permanent magnet pieces 4, 4b, 4c of the first embodiment, comparative example 1, and comparative example 2 is made the same, and the peak value of the magnetic flux density is measured for each opening angle.

The bar graph of FIG. 10 shows the magnetic flux density generated on the outer peripheral surface of Comparative Example 2 and the rotor of Embodiment 1 when the peak value of the magnetic flux density generated on the outer peripheral surface of the rotor of Comparative Example 1 is 1. The ratio of peak values is shown for each opening angle. As shown in the figure, the plate-shaped permanent magnet 4b (Comparative Example 1) having a uniaxial orientation line is a substantially fan-shaped permanent magnet 4c (Comparative Example 2) having a uniaxial orientation line. The peak value of the magnetic flux density generated on the outer peripheral surface of the child increases by 0.7% at an opening angle of 20 degrees, 1.4% at 30 degrees, and 2.4% at 40 degrees. Further, the plate-shaped permanent magnet 4b (Comparative Example 1) having a uniaxial orientation line is substantially fan-shaped and the permanent magnet piece 4 having an arcuate orientation direction line (Embodiment 1) can be used as a rotor. The peak value of the magnetic flux density generated on the outer peripheral surface of the film increases by 1.2% at an opening angle of 20 degrees, 2.8% at 30 degrees, and 4.5% at 40 degrees.
Thus, the magnetic force generated on the outer peripheral surface of the rotor can be increased by changing the shape of the permanent magnet piece from a plate shape to a substantially fan-shaped cross section and changing the orientation direction line from an uniaxial direction to an arc shape. it can.

Next, the magnetic flux distribution generated around the permanent magnet piece was examined and compared for the rotors of Embodiment 1 and Comparative Example 1 by magnetic field analysis.
FIG. 12A is a magnetic field analysis result showing the leakage magnetic flux in the direction of the rotation axis 2 of the permanent magnet piece 4 of the first embodiment, and the analysis result of the region within the dotted line of the rotor 1 shown on the right side in the figure. Is shown enlarged on the left side of the figure. FIG. 12B is a magnetic field analysis result showing leakage magnetic flux in the direction of the rotation axis 2b of the permanent magnet piece 4b of Comparative Example 1, and shows an analysis result of a region within a dotted line of the rotor 1b shown on the right side in the figure. It is shown enlarged on the left side. The arrow in the analysis result indicates the leakage magnetic flux. As can be seen from the figure, the leakage magnetic flux in the direction of the rotating shaft 2 of the permanent magnet piece 4 of the first embodiment is significantly reduced as compared with the comparative example 1.

  As described above, in the rotor according to the first embodiment, since the orientation direction line of the permanent magnet piece is a convex curve in the rotation axis direction of the rotor, the magnetic flux flowing in the rotation axis direction of the rotor is reduced. At the same time, the magnetic flux flowing in the outer circumferential direction of the rotor can be increased, and the magnetic force generated on the outer circumferential surface of the rotor can be increased. Therefore, it is possible to improve the torque and high efficiency of the rotating machine, and to reduce energy consumption. Moreover, since the volume of the permanent magnet piece required to generate the same magnetic force can be reduced, the rotating machine can be reduced in size. The shape of the permanent magnet piece is not limited to the shape used in the first embodiment. If the orientation direction line of the permanent magnet piece is a convex curve in the rotation axis direction of the rotor, the outer periphery of the rotor The magnetic force generated on the surface can be increased.

  Moreover, if the cross-sectional shape of the permanent magnet piece is substantially fan-shaped and the outer-circular arc of the substantially fan-shape is arranged so as to face the rotation axis direction of the rotor, the magnetic force generated on the outer peripheral surface of the rotor can be increased. it can. Further, since the permanent magnet piece is tapered in the radial direction, the permanent magnet piece can be prevented from slipping out in the outer circumferential direction of the rotor without fixing the permanent magnet piece to the iron core piece with an adhesive or the like. Therefore, high efficiency of the rotating machine can be realized, and the manufacturing process can be simplified.

  In addition, since the permanent magnet pieces can be formed as divided pieces of ring-shaped permanent magnets magnetically oriented in the circumferential direction, it is not necessary to manufacture each permanent magnet piece having an arcuate orientation direction line. In addition, a large number of permanent magnet pieces can be easily manufactured and the material yield can be improved.

Embodiment 2. FIG.
In the first embodiment, the cross-sectional shape of the permanent magnet piece is a substantially fan shape obtained by cutting off the center side of the fan shape by an arc concentric with the fan shape. However, the cross-sectional shape of the permanent magnet piece is not limited to this. In the second embodiment, a case where the cross-sectional shapes of the permanent magnet pieces are different will be described. Note that portions similar to those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

FIG. 13 is a conceptual diagram of a permanent magnet type rotor (hereinafter referred to as a rotor) in the second embodiment, and FIG. 14 is a partially enlarged view of FIG. 13, and the permanent magnet piece in the second embodiment. FIG.
As shown in FIG. 13, the permanent magnet pieces 4d are arranged close to the outermost peripheral surface of the rotor 1d. And as shown in FIG. 14, the cross-sectional shape of the permanent magnet piece 4d is a substantially fan shape obtained by cutting off the center side of the fan shape with a straight line, and the side 40d on the outer peripheral side of the rotor 1d is a straight line. For comparison, FIG. 15 shows a case in which the cross-sectional shape of the permanent magnet piece is a substantially fan shape obtained by cutting off the center side of the fan shape by an arc concentric with the fan shape (the side 40 on the rotor outer periphery side of the permanent magnet piece is (In the case of a concave arc on the outer periphery of the rotor).
As can be seen from the figure, the permanent magnet piece is positioned on the rotor outer circumference side when the permanent magnet piece has a linear shape (FIG. 14) rather than a concave shape (FIG. 15). Can be approached. That is, by making the side 40d on the outer periphery side of the rotor of the permanent magnet piece 4d straight, the distance between the stator (not shown) arranged on the outer periphery side of the rotor and the permanent magnet piece 4d is shortened. The road can be shortened. Therefore, even if the permanent magnet pieces have the same volume, the magnetic flux generated on the outer peripheral surface of the rotor can be increased by adopting the shape of the permanent magnet pieces 4d of the second embodiment.

  FIG. 16 is a detailed view showing the shape of a permanent magnet piece 4e according to another example of the second embodiment, and corresponds to FIG. The permanent magnet piece 4e of another example has a substantially sector shape in which the cross-sectional shape is cut off by the convex arc in the center direction of the sector shape. That is, as shown in FIG. 16, the side 40e on the rotor outer peripheral side of the permanent magnet piece 4e has a circular arc shape convex toward the rotor outer peripheral side, and in another example of the second embodiment, the side 40e is the rotor 1e. It overlaps with a virtual circle on the outermost peripheral surface. Thereby, the distance between the permanent magnet piece and the stator can be further shortened, and the magnetic flux generated on the outer circumferential surface of the rotor can be further increased.

  In the permanent magnet pieces 1d and 1e in the second embodiment, the side of the permanent magnet pieces 1d and 1e located on the rotating shaft side (rotor center side) has an arc shape, but is not necessarily limited thereto. It may be as shown in FIG. FIG. 17 is a conceptual diagram showing another example of the rotor 1f according to the second embodiment. The side 40f of the permanent magnet piece 4f located on the side of the rotating shaft 2f is linear, and is located on the outer circumferential side of the rotor. The side 40g is also linear. In this case, the cross section of the permanent magnet piece 4f has a trapezoidal substantially fan shape.

FIG. 18 is an explanatory view for explaining a method of manufacturing the permanent magnet piece 4f used in the rotor 1f of another example in the second embodiment. The manufacturing method of the permanent magnet piece 4f is the same method as the manufacturing method of the permanent magnet piece 4 of the first embodiment, and after the ring-shaped permanent magnet 67 is oriented and formed (FIG. 18A), the ring-shaped permanent magnet. It is divided radially from the central axis 67 (FIG. 18B). Further, the divided pieces are arranged and fixed, and the surfaces corresponding to the inner periphery and the outer periphery of the ring-shaped permanent magnet 67 are subjected to surface grinding, thereby forming a substantially fan-shaped permanent magnet piece 4f having a trapezoidal cross section (FIG. 18C )).
Further, the permanent magnet piece 4d used for the rotor 1d in the second embodiment is also formed by the same method as the permanent magnet piece 4f, and the surface corresponding to the inner periphery of the ring-shaped permanent magnet 67, that is, the rotation of the permanent magnet piece 4d. It is obtained by surface grinding only the surface located on the outer peripheral side of the child. In the case of another permanent magnet piece 4e, the surface of the permanent magnet piece 4e located on the outer periphery of the rotor may be ground in an arc shape.
The orientation direction lines of the permanent magnet pieces 4d, 4e, and 4f formed in this way are arc-shaped curves along the circumferential direction before surface grinding. Therefore, most of the magnetic flux generated from the permanent magnet pieces 4d, 4e, and 4f flows to the outer peripheral side of the rotors 1d, 1e, and 1f, and the leakage magnetic flux to the rotating shaft side of the rotors 1d, 1e, and 1f can be reduced. .

  Note that the method of manufacturing the permanent magnet pieces 4d and 4f is not limited to the method of dividing the annular ring-shaped permanent magnet 67 and performing surface grinding as shown in FIG. For example, if a substantially ring-shaped permanent magnet is formed using a substantially ring-shaped cavity that has a polygonal shape (for example, a regular dodecagon) on both the outer peripheral side and the inner peripheral side, the permanent magnet is obtained by dividing it radially. The piece 4f can be obtained. Also, if a substantially ring-shaped permanent magnet is formed using a substantially ring-shaped cavity having a circular shape on the outer peripheral side and a polygonal shape (for example, a regular dodecagon) on the inner peripheral side, this can be made radial. The permanent magnet piece 4d can be obtained by dividing.

As described above, the rotor according to the second embodiment has the same effects as those of the first embodiment and the following effects.
In the second embodiment, the rotor outer peripheral side of the permanent magnet piece used in the rotor is a straight line or a circular arc convex toward the rotor outer peripheral side, so that the magnetic path from the permanent magnet piece to the stator Can be shortened. Therefore, the magnetic force generated on the outer peripheral surface of the rotor can be further increased, the torque of the rotating machine can be improved and high efficiency can be realized, and the energy consumption can be reduced.

1, 1a, 1d, 1e, 1f, 10a rotor, 2, 2f rotating shaft,
30, 30a, 3a Iron core pieces, 4, 4d, 4e, 4f Permanent magnet pieces.

Claims (6)

A rotating shaft, a plurality of substantially fan-shaped iron core pieces made of a ferromagnetic material and arranged at equal intervals in the circumferential direction on the outer peripheral side of the rotating shaft, and the iron core pieces and the circumferential direction alternate between the iron core pieces. The permanent magnet rotor is composed of a plurality of permanent magnet pieces arranged in the same manner, and the permanent magnet pieces have the same polarity on the surface facing the permanent magnet pieces arranged adjacent to each other in the circumferential direction. A permanent magnet type rotor, wherein the permanent magnet piece is arranged so as to be a pole, and an orientation direction line of the permanent magnet piece is a convex curve in a rotation axis direction of the permanent magnet type rotor. 2. The permanent magnet type rotor according to claim 1, wherein an orientation direction line of the permanent magnet piece is an arc shape. The cross-sectional shape of the permanent magnet piece is substantially fan-shaped, and the substantially fan-shaped outer circumferential arc of the permanent magnet piece is arranged so as to face the rotation axis direction of the rotor. Or a permanent magnet type rotor according to 2; The cross-sectional shape of the permanent magnet piece is a substantially fan shape in which the center side of the fan shape is cut off by an arc concentric with the fan center, the number of poles of the permanent magnet rotor is n, and the outer side of the permanent magnet rotor is The radius is Ro, the distance from the center of the permanent magnet type rotor to the fan center of the permanent magnet piece is R, the substantially fan-shaped opening angle of the permanent magnet piece is 2θ, and it is located on the rotating shaft side of the permanent magnet piece The following conditions (1) to (3) must be satisfied, where Rmo is the arc radius of the arc to be performed and Rmi (where Rmo> Rmi) is the arc radius of the arc located on the outer periphery of the rotor of the permanent magnet piece: 4. The permanent magnet type rotor according to claim 3, wherein
2π / θ> 2 (1)
R> Ro / cos (π / n) and Rmi> (R−Ro) / cos θ (2)
R> Ro / cos (π / n) and Rmo <Rsin (π / n) / cos (π / 2−π / n−θ) (3) 4. The permanent magnet type rotation according to claim 3, wherein a cross-sectional shape of the permanent magnet piece is a substantially fan shape in which a center side of the sector is cut off by a straight line or a convex arc toward the outer periphery of the rotor. Child. The permanent magnet type rotor according to any one of claims 1 to 5, wherein the plurality of iron core pieces are annularly coupled in a part of the axial direction.

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