JP2020162191A - Axial-gap type rotary electric machine - Google Patents

Abstract

To provide a rotor structure axial gap type rotary electric machine with a small influence on magnetic properties, that can be strongly held with no damage of a permanent magnet.SOLUTION: According to an axial gap type rotary electric machine 1000, a rotor 200 comprises a disk-shaped base 220, a plurality of magnets 210 annularly arranged on a disk surface of the base 220 opposed to a stator 200, and a plurality of holding parts 230 for holding the magnets 210 provided on the disk surface. A circumferential direction reduction part 211 whose length is reduced in a circumferential direction of the base 220 is provided to the plurality of magnets 210. A circumferential direction enlargement part 231 whose length in the circumferential direction of the base 220 is enlarged is provided to the plurality of holding parts 230. The circumferential direction enlargement parts 231 of two holding parts 230 arranged side by side in the circumferential direction of the base 220 each come into contact with the circumferential direction reduction part 211 of one magnet 210 arranged between the two holding parts 230 among the plurality of magnets 210.SELECTED DRAWING: Figure 1(b)

Description

The present invention relates to an axial gap type rotary electric machine.

The axial gap type rotary electric machine has a structure in which a disk-shaped rotor (rotor) and a stator (stator) are arranged so as to face each other in the direction of the rotation axis. Since the area of the facing surface between the rotor and the stator that generates rotational torque increases in proportion to the square of the rotor diameter, the axial gap type rotary electric machine has a shape with a small aspect ratio, that is, the radial dimension rather than the axial dimension. The large shape makes it easy to improve characteristics such as output and efficiency.

On the other hand, the axial gap type rotary electric machine has a larger rotor diameter than the conventional radial gap type rotary electric machine, so that a stronger holding structure against centrifugal force is required. In particular, in the case of a rotor structure in which multiple permanent magnets are divided in the circumferential direction and arranged in multiple directions, it is important to hold the permanent magnets in the circumferential direction and the axial direction in addition to the radial direction in order to prevent misalignment and scattering of the independent permanent magnets. It becomes. However, if a large holding member or a metal holding member is used to increase the holding strength, the rotor diameter is increased, the space for arranging the permanent magnets is reduced, and the magnetic characteristics are deteriorated due to the generation of eddy currents in the holding member.

Regarding the holding structure of the permanent magnet in the rotor of such an axial gap type rotary electric machine, for example, Patent Document 1 describes a semi-conical recess provided on the outer peripheral edge of the permanent magnet and a base material (yoke). Disclosure of a radial gap type rotary electric machine including a screw hole provided in the machine and a countersunk screw screwed into the screw hole with the head housed in the recess to fix a permanent magnet to a base material (yoke). Has been done.

Japanese Unexamined Patent Publication No. 2017-41937

In Patent Document 1, there is a possibility that the strength of the permanent magnet is lowered due to the formation of the concave portion on the outer peripheral edge portion, or the concave portion comes into contact with the head of the countersunk head screw and excessive stress is generated around the concave portion. Further, if the concave portion is enlarged in order to suppress the stress concentration around the concave portion and to increase the strength of the countersunk head screw which is a holding member, the magnetic characteristics (for example, magnetic permeability, magnetic flux density, etc.) may be significantly reduced.

An object of the present invention is to provide an axial gap type rotary electric machine having a rotor structure that has a small influence on magnetic characteristics and can firmly hold a permanent magnet.

In order to achieve the above object, the present invention relates to an axial gap type rotor in which a stator and a rotor face each other through a gap provided along the central axis direction of the rotor. A disk-shaped base, a plurality of magnets arranged along the circumferential direction of the base on the disk surface of the base facing the stator, and the plurality of magnets arranged between the plurality of magnets, respectively. The plurality of magnets have a plurality of holding portions for holding the magnets, and each of the plurality of magnets has a circumferential reducing portion whose length in the circumferential direction decreases toward the outside in the radial direction of the base. Each of the plurality of holding portions has a circumferential expanding portion whose length in the circumferential direction of the base increases toward the outside in the radial direction of the base, and among the plurality of holding portions, the said The circumferential expansion of the two holding portions arranged side by side in the circumferential direction of the base, respectively, reduces the circumferential direction of one magnet arranged between the two holding portions of the plurality of magnets. It is in contact with the part.

Alternatively, in an axial gap type rotor, a stator formed by arranging a core and a coil wound around the core in an annular shape, and a rotor facing the axial end surface of the stator via a gap. The rotor has a base and a plurality of magnets annularly arranged on the stator-side end surface of the base, and the magnets have a circumferential width toward the outside in the radial direction. A holding member having an expanding portion and a decreasing portion whose circumferential width decreases radially outward from the expanding portion, and a holding member in contact with the circumferential side surface of the magnet is provided between the plurality of magnets. Have.

According to the present invention, it is possible to hold the permanent magnet while suppressing the deterioration of the magnetic characteristics of the rotating electric machine and the stress concentration of the permanent magnet. Therefore, the axial gap type rotating electric machine can be miniaturized, have a high output, and have a high value. Efficiency can be achieved. Issues, configurations and effects other than those described above will be clarified by the description of the following embodiments.

It is sectional drawing of the axial gap type rotary electric machine according to 1st Embodiment of this invention. It is an enlarged perspective view of the gap between the stator and the rotor of the axial gap type rotary electric machine according to the 1st Embodiment of this invention. It is a partial plan view of the rotor seen from the stator side of the axial gap type rotary electric machine according to 1st Embodiment of this invention. It is a perspective view of the rotor before covering the surface of the permanent magnet of the axial gap type rotary electric machine by 1st Embodiment of this invention with a holding member. It is a perspective view of the rotor which covered the surface of the permanent magnet of the axial gap type rotary electric machine by 1st Embodiment of this invention with a holding member. It is a projection view of the core and the permanent magnet in the direction of the center of rotation used for analyzing the influence of the dimensional parameter of the permanent magnet of the axial gap type rotating electric machine on the induced voltage by the finite element method according to the first embodiment of the present invention. .. It is a graph which analyzed the influence which the dimensional parameter of the permanent magnet of the axial gap type rotary electric machine by 1st Embodiment of this invention has on the induced voltage by the finite element method. It is a conceptual diagram explaining the centrifugal force applied to the permanent magnet of the axial gap type rotary electric machine according to the 1st Embodiment of this invention, and the holding force of the permanent magnet by the holding member. It is a perspective view of the core of the axial gap type rotary electric machine according to the 2nd Embodiment of this invention. It is a rotation axis direction projection drawing of the core and the permanent magnet of the axial gap type rotary electric machine according to the 2nd Embodiment of this invention. It is a perspective view and cross-sectional perspective view of the rotor of the axial gap type rotary electric machine according to the 3rd Embodiment of this invention. It is an exploded view of the rotor of the axial gap type rotary electric machine according to the 3rd Embodiment of this invention. It is an exploded view of the rotor using another holding member of the axial gap type rotary electric machine according to the 3rd Embodiment of this invention. It is sectional drawing of the rotor of the axial gap type rotary electric machine according to 4th Embodiment of this invention. It is a conceptual diagram explaining the centrifugal force applied to the permanent magnet of the rotor of the axial gap type rotary electric machine according to the 4th embodiment of the present invention, and the holding force of the permanent magnet by the collar portion and the holding member. It is a perspective view and cross-sectional perspective view of the rotor of the axial gap type rotary electric machine according to the 5th Embodiment of this invention. It is an exploded view of the rotor of the axial gap type rotary electric machine according to the 5th Embodiment of this invention. It is an exploded view of the rotor excluding the holding member of the axial gap type rotary electric machine according to the 6th Embodiment of this invention.

Hereinafter, the configuration and operation of the axial gap type rotary electric machine according to the first to sixth embodiments of the present invention will be described with reference to the drawings. In each figure, the same reference numerals indicate the same parts.

[First Embodiment]
FIG. 1A is a cross-sectional perspective view showing the configuration of the axial gap type motor 1000 (motor 1000) according to the first embodiment of the present invention. As shown in FIG. 1A, the motor 1000 is located on both sides of the stator (stator) 100 having a flat cylindrical shape and the stator 100 in the axial direction (hereinafter, axial direction) of the rotation axis AX. Two disk-shaped rotors (rotors) 200 that rotate around the center AX, a shaft 500 that is connected to the two rotors 200 and rotates around the axis AX, and a stator 100 and a rotor 200 are housed in the stator 100. It has a housing 300 to be fixed, and two brackets 400 connected to both ends of the housing 300 in the axial direction of the axis AX and supporting the shaft 500 via a bearing 600. The shaft 500 is rotatably coupled to the bracket 400 via a bearing 600. Further, the bracket 400 is assembled and fixed to both ends of the housing 300. A terminal block (not shown) is provided on the outer peripheral side surface of the housing 300, and an external output unit is electrically connected via the terminal block.

FIG. 1B is an enlarged perspective view of the gap G between the stator 100 and the rotor 200. The axial direction, radial direction, and circumferential direction of the rotor 200 are shown in the figure. The radial direction and the circumferential direction are not limited to the illustrated directions. The same applies to FIG. 1 (c). FIG. 1C is a partial plan view of the rotor 200 as viewed from the stator 100 side. As shown in FIG. 1 (b), the motor 1000 has eight permanent magnets 210 and twelve cores 110 around which a coil 120 for energizing a three-phase AC power supply is wound, and is concentrated in eight poles and 12 slots. It is a winding three-phase motor.

As shown in FIG. 1B, the motor 1000 has a so-called double rotor type axial gap in which a substantially annular stator 100 is arranged so as to face each other so that two disk-shaped rotors 200 are sandwiched from the axial direction. It is a type rotary electric motor. A plurality of (12 in this embodiment) core members 101 are arranged in an annular shape around the shaft 500 on the stator 100. Each core member 101 has a core 110 whose both end surfaces are trapezoidal pillars, a tubular bobbin (not shown) that covers the side surface of the core 110, and a winding wound around the side surface of the core 110 via the bobbin. It includes a wire 120. Each of the twelve core members 101 arranged in an annular shape is integrally molded by the resin 130 in the housing 300, and is molded into one stator 100. The axial end faces of the core 110 are not limited to trapezoids as long as the circumferential width on the outer side in the radial direction is longer than the circumferential width on the inner side in the radial direction so that an annular arrangement can be easily performed. Details will be described in the second embodiment, but for example, in addition to the trapezoid, a triangle or a polygon in which a part of the lower base side of the trapezoid is cut off may be used. In this specification, these shapes are collectively referred to as a substantially trapezoid.

Each rotor 200 has a disk-shaped base 220 and a plurality of rotors 200 (eight in the present embodiment) arranged in an annular shape on the disk surface of the base 220 facing the stator 100 along the circumferential direction of the base 220. It has a permanent magnet 210 and a holding member 230 as a plurality of holding portions that are arranged between the plurality of permanent magnets 210 and hold the plurality of permanent magnets 210. Each holding member 230 is arranged between two permanent magnets 210 arranged side by side in the circumferential direction of the base 220, and in the present embodiment, the same number of eight as the permanent magnets 210 are on the disk surface of the base 220. It is located in.

The permanent magnet 210 is made of a bond magnet, the base 220 is made of iron, and the holding member 230 is made of resin. In this embodiment, iron is used as a material having a high magnetic permeability so that the base 220 plays the role of a yoke (joint iron). However, the base 220 is made of a non-magnetic strength member, the strength member, and a magnet. A disk-shaped yoke may be arranged between them.

As shown in FIG. 1 (c), each of the plurality of permanent magnets 210 has a shape as if the corners of a fan shape were cut off. Specifically, the permanent magnet 210 has a circumferential expansion portion 212 whose circumferential length increases from the radial inner side to the radial outer direction, and a circumferential length increasing from the circumferential expansion portion 212 toward the radial outer side. It is provided with a circumferential reduction unit 211 for reduction. That is, the permanent magnet 210 of the present embodiment has a shape in which the length of the base 220 in the radial direction expands in a tapered shape from the inside to the outside in the radial direction of the base 220 and then decreases in a tapered shape. ..

Further, each of the plurality of holding members 230 has a shape along the circumferential side surface of the magnet 210. Specifically, the circumference in which the circumferential length is tapered outward from the circumferential equal width portion 232 and the circumferential equal width portion 232 in which the circumferential length is constant toward the radial outer side. It is composed of a direction expanding portion 231. That is, the holding member 230 of the present embodiment has a shape in which the length of the base 220 in the radial direction is held constant from the inside to the outside in the radial direction of the base 220 and then expands in a tapered shape. ..

The circumferential reduction portion 211 of the permanent magnet 210 is in surface contact with the circumferential expansion portion 231 of two adjacent holding members 230 on one side and the other side in the circumferential direction of the base 220, respectively. In other words, the circumferential expansion portion 231 of the two holding members 230 arranged side by side in the circumferential direction of the base 220 among the plurality of holding members 230 is the two holding members 230 of the plurality of permanent magnets 210, respectively. It is in surface contact with the circumferential reduction portion 211 of one permanent magnet 210 arranged between the two. The circumferential expansion section 231 and the circumferential reduction section 211 do not necessarily have to be in surface contact, and may be in contact with each other at one or more points.

Similarly, the circumferential expansion portion 212 of the permanent magnet 210 is in surface contact with the circumferential equal width portion 232 of two adjacent holding members 230 on one side and the other side in the circumferential direction of the base 220, respectively. There is. The circumferentially enlarged portion 212 and the circumferentially equal width portion 232 do not necessarily have to be in surface contact, and may be in contact with each other at one or more points.

Further, the holding member 230 is integrally molded with a resin mold together with the base 220 on which the permanent magnet 210 is arranged.

The motor 1000 having such a configuration operates as follows. An inverter (not shown) output line is connected to the terminal block, and a three-phase alternating current is applied to the coil 120. As a result, a rotating magnetic field is formed in the stator 100, and the rotating magnetic field attracts and repels the DC magnetic field formed in the rotor 200 by the permanent magnet 210 to generate a rotational torque in the rotor 200. As a result, the rotor 200 rotates and the motor 1000 is driven.

At this time, centrifugal force is applied to the rotor 200 in the radial direction, magnetic attraction force is applied in the axial direction, rotational torque is applied in the circumferential direction, and the like. In particular, a large centrifugal force is applied to each of the permanent magnets 210 having a large specific gravity arranged in a ring shape on the base 220. Since the shape of the permanent magnet 210 according to the present embodiment as seen from the stator 100 side shown in FIG. 1C is a shape that effectively utilizes the magnetic flux described later, the amount of magnetic flux per weight can be increased. .. Therefore, the amount of magnets required to obtain a desired amount of magnetic flux can be reduced, and the centrifugal force can be reduced. Further, even if the permanent magnet 210 receives a centrifugal force toward the outer diameter of the base 220, the circumferential reduction portion 211 of the permanent magnet 210 presses against the circumferential expansion portion 231 of the holding member 230, so that the permanent magnet 210 is Does not scatter. Further, since the holding member 230 is made of resin, there is no increase in leakage flux or eddy current due to the arrangement of the holding member 230.

Next, the results of analyzing the influence of the shape of the permanent magnet 210 on the characteristics of the motor 1000 by the finite element method will be described with reference to FIGS. 1 (f) and 1 (g). FIG. 1 (f) is an axial projection drawing of the permanent magnet 210 and the core 110 used in the analysis. Using the inner diameter φin and outer diameter φout of the permanent magnet 210 shown in FIG. 1 (f) and the distance (between poles) D between adjacent permanent magnets as parameters, the induced voltage generated when the rotor 200 is rotated with no load is analyzed. did. The number of turns of the coil 120, the rotation speed of the rotor 200, the temperature of the motor 1000, and the like other than the above parameters are set to constant values. Therefore, the amount of change in the induced voltage represents how the shape of the permanent magnet 210, which changes by changing the parameter, affects the amount of magnetic flux passing through the core 110.

FIG. 1 (g) is a graph showing the relationship between the reduction rate of the magnet amount of the permanent magnet 210 and the reduction rate of the induced voltage when the parameters are changed. As shown in FIG. 1 (g), the reduction rate of the induced voltage with respect to the reduction rate of the magnet amount of the permanent magnet 210 becomes maximum when the outer diameter φout of the permanent magnet is reduced, and then when the inner diameter φin is increased. , And it can be seen that the distance D decreases in the order of increase. In particular, the reduction rate of the induced voltage when the interpole D is increased is extremely small. Therefore, by increasing the pole-to-pole D and reducing the axial cross section of the permanent magnet 210, the amount of magnetic flux per unit weight emitted from the permanent magnet 210 and passing through the core 110 can be increased. Therefore, the weight of the permanent magnet 210 can be reduced, and the centrifugal force acting on the permanent magnet 210 can be reduced.

FIG. 1H is a conceptual diagram illustrating the centrifugal force Fc applied to the permanent magnet 210 and the holding force Fr of the permanent magnet 210 by the holding member 230. Due to the centrifugal force Fc applied to the permanent magnet 210, the permanent magnet 210 tends to move in the outer diameter direction of the base 220. However, when the circumferential reduction portion 211 of the permanent magnet 210 comes into contact with the circumferential expansion portion 231 of the holding member 230, a reaction force Fr is applied to the permanent magnet 210 and the permanent magnet 210 does not scatter and is a circle of the base 220. Stay on the board. Further, since the force acting on the permanent magnet 210 is mainly compressive stress, even if a bond magnet having a relatively low strength is used for the permanent magnet 210, it can be held without being damaged.

Based on the above, according to the rotor 200 in which a space is secured between the poles D of the permanent magnet 210 and a holding member 230 for holding the permanent magnet 210 is arranged in the space, the limited disk surface of the rotor can be effectively used. Both the magnetic characteristics of the permanent magnet 210 and the mechanical strength can be achieved. Therefore, it is possible to improve the output density (small size, high output) of the motor 1000, improve the efficiency, and suppress the stress concentration of the permanent magnet 210. Furthermore, it is possible to reduce the cost by reducing the amount of permanent magnets.

In the present embodiment, the circumferential reduction portion 211 is provided outside the permanent magnet 210 in the radial direction of the base 220, and the circumferential expansion portion 231 is provided outside the holding member 230 in the radial direction of the base 220. Although the provided example is shown, it is sufficient that the circumferential reduction unit 211 and the circumferential expansion unit 231 can come into contact with each other, and the positions of the circumferential reduction unit 211 and the circumferential expansion unit 231 can be changed as appropriate. For example, the shape is continuous from the inside in the radial direction of the base 220 (the inner peripheral side of the base 220), the intermediate portion in the radial direction of the base 220, or from the inside to the outside in the radial direction of the base 220. You may. Further, the circumferential reduction portion 211 and the circumferential expansion portion 231 are not limited to the tapered shape shown in FIG. 1C, and may have a comb tooth shape, an arc shape, or a wavy shape.

The holding member 230 is made of PBT (polybutylene terephthalate resin), BMC (unsaturated polyester resin), FRP (fiber reinforced plastic), etc. containing glass fiber in order to secure strength and suppress leakage magnetic flux and eddy current. It is desirable to use a resin material such as CFRP (carbon fiber reinforced plastic). Further, if the influence on the leakage flux and the eddy current can be ignored, the metal such as aluminum or iron may be used. By using an injection-moldable bond magnet as the material of the permanent magnet 210, the degree of freedom in shape is increased, and it becomes easy to form the circumferential reduction portion 211 in various ways.

Further, although the holding member 230 used in the above description is divided into a plurality of parts, it may be a holding member including the holding member 230 and the holding portion base 233 that integrates the holding member 230. For example, the permanent magnet 210 (FIG. 1 (d)) arranged on the base 220 in the circumferential direction is formed by integrally forming the permanent magnet 210 (FIG. 1 (d)) with the holding member 230 as shown in FIG. 1 (e). The surface of the magnet may be covered. By covering the surface of the permanent magnet 210 with the holding member base 233, the permanent magnet 210 can be protected and local detachment can be prevented. Alternatively, the holding member base is formed in an annular shape on the inside (axial side) of the plurality of permanent magnets 210 arranged in an annular shape, and eight protruding holding members 230 are radially outward from the holding member base. It may be a shape that extends to (not shown). Alternatively, an annular holding member base may be provided on the outside of the plurality of permanent magnets 210 arranged in an annular shape, and eight holding member 230 may extend radially inward from the holding member base. In this case, the material of the permanent magnet 210 may be a ferrite or neodymium sintered magnet. Further, as a method of fixing the holding member 230 to the base 220, not only a method of molding a mold resin integrally with the base 220 but also an adhesive or the like may be used.

Further, in the present embodiment, since the number of permanent magnets 210 is 8 and the number of cores 110 is 12, there are 8 poles and 12 slots, and the ratio of the number of poles to the number of slots is 2: 3. When the ratio of the number of poles to the number of slots is set to 2: 3 in this way, the permanent magnet is compared with the fractional slots (for example, 10 poles 12 slots and 14 poles 12 slots) in which the number of poles and the number of slots are close to each other as compared with the present embodiment. Since the angle assigned to one pole is larger than the angle assigned to the core for one slot, even if the pole-to-pole D of the permanent magnet 210 is expanded, the effect on the electrical characteristics is small, and the holding member 230 is arranged and fixed. It has the advantage of being easy to remove.

In the present embodiment, the double rotor type axial gap type rotary motor has been described as an example, but it can also be applied to an axial gap type electric motor having another structure. Furthermore, it may be applied to a generator instead of a motor.

<Summary>
Next, the features and effects included in the present embodiment will be described. The permanent magnet 210 according to the present embodiment is formed with a circumferential reduction portion 211, and the holding member 230 is formed with a circumferential expansion portion 231. Therefore, even if the permanent magnet 210 receives a centrifugal force toward the outer diameter of the base 220, the circumferential reduction portion 211 of the permanent magnet 210 presses against the circumferential expansion portion 231 of the holding member 230, so that the permanent magnet 210 Does not scatter. Further, since the circumferential reduction portion 211 of the permanent magnet 210 and the circumferential expansion portion 231 of the holding member 230 have a tapered shape, they are easy to make and hard to break. Further, since the circumferential reduction portion 211 of the permanent magnet 210 and the circumferential expansion portion 231 of the holding member 230 are in surface contact with each other on the tapered surface, they are not easily broken.

Further, the circumferential reduction portion 211 is provided on the outer diameter side of the permanent magnet 210 in the radial direction of the base 220, and the circumferential expansion portion 231 is provided on the outer diameter side of the holding member 230 in the radial direction of the base 220. Has been done. Therefore, the permanent magnet 210 is compressed by the reaction force from the circumferential expansion portion 231 of the holding member 230 applied to the circumferential reduction portion 211 provided on the outer diameter side and the centrifugal force applied to the permanent magnet 210. Therefore, even if a magnet having a relatively low strength without applying tensile stress to the permanent magnet 210 is used, it can be held without being damaged.

The ratio of the number of poles to the number of slots is 2: 3. Therefore, the angle assigned to one permanent magnet pole is larger than the angle assigned to the core for one slot, as compared to fractional slots (for example, 10 poles 12 slots or 14 poles 12 slots) whose number of poles is close to the number of slots. The effect on the electrical characteristics is small, and the holding member 230 can be easily arranged and fixed.

Further, the holding member 230 is made of resin. Therefore, even if the holding member 230 is arranged, the leakage flux and the eddy current do not increase. Further, the holding member 230 is integrally molded with a resin mold together with the base 220 on which the permanent magnet 210 is arranged. Therefore, the permanent magnet 210 can be securely fixed to the base 220. Further, the holding member 230 may cover the surface of the permanent magnet 210. By covering the surface of the permanent magnet 210 with the holding member 230, the permanent magnet 210 can be protected and local detachment can be prevented.

Further, by increasing the pole-to-pole D and reducing the cross-sectional area of the permanent magnet 210 in the rotation axis direction, the amount of magnetic flux per unit weight emitted from the permanent magnet 210 to the core 110 is increased. Therefore, the weight of the permanent magnet 210 can be reduced, and the centrifugal force can be reduced.

Further, according to the rotor 200 in which a space is secured between the poles D of the permanent magnet 210 and a holding member 230 for holding the permanent magnet 210 is arranged in the space, the limited disk surface of the rotor is effectively used and the permanent magnet 210 is permanently used. Both the magnetic characteristics of the magnet 210 and the mechanical strength can be achieved. Therefore, it is possible to improve the output density (small size, high output) of the motor 1000, improve the efficiency, and suppress the stress concentration of the permanent magnet 210. Furthermore, it is possible to reduce the cost by reducing the amount of permanent magnets.

[Second Embodiment]
FIG. 2A shows a perspective view of the core 2110 of the axial gap type motor 2000 according to the second embodiment of the present invention. Further, FIG. 2B shows an axial projection drawing of the core 2110 and the permanent magnet 210 of the axial gap type motor 2000 according to the second embodiment. The description of the same configuration as that of the first embodiment will be omitted.

As shown in FIG. 2A, the plurality of cores 2110 arranged in an annular shape are pillars having two axial end faces arranged so as to face the rotor 200 as a bottom surface. The shape of the axial end face of each core 2110 is a trapezoidal portion 2113 in which the length in the circumferential direction of the rotor 200 increases toward the outside in the radial direction of the rotor 200, and a trapezoidal portion 2113 in which the length in the circumferential direction of the rotor 200 increases. The shape is a combination of the rectangular portion 2114 having the same side as the bottom side. The trapezoidal portion 2113 of the present embodiment is an isosceles trapezoidal shape, and its two legs (sides) form a tapered portion 2111 that expands in the outer diameter direction of the rotor 200.

Further, as shown in FIG. 2B, one leg of the trapezoidal portion 2113 is substantially parallel to the leg of the trapezoidal portion 2113 of the other core 2110 adjacent to the rotor 200 in the circumferential direction. Further, two short sides facing each other in the rectangular portion 2114 form a straight portion 2111. Further, the core 2110 is formed by laminating a rectangular thin plate magnetic material such as an electromagnetic steel plate, an iron-based amorphous metal, or a nanocrystal in the radial direction of the rotor 200. The laminated shape is the same for the core 110 of the first embodiment, and the difference between the core 2110 and the core 110 is the presence or absence of the rectangular portion 2114.

By the way, when the thickness of the thin plate magnetic material varies, the radial dimension of the core 2110 varies. However, in the core 2110 of the second embodiment, the radial dimension of the core 2110 can be accommodated within a predetermined dimensional error range by adjusting the number of stacked rectangular portions 2114.

Further, as shown in FIG. 2B, the permanent magnet 210 according to the present embodiment is provided with a notch portion 214 on the outer diameter side, and a circumferential reduction portion 211 is formed. By combining the core 2110 and the permanent magnet 210 having such a shape, the projected shapes of the permanent magnet 210 and the core 2110 in the axial direction are similar to those of the core 110 of the trapezoidal column as shown in FIG. 1 (b). Therefore, even if the permanent magnet 210 is provided with the notch portion 214 for forming the circumferential reduction portion 211, the amount of magnetic flux passing through the core 2110 is less likely to decrease. Therefore, according to the axial gap type motor 2000 according to the present embodiment, it is possible to suppress variations in motor characteristics due to variations in the cross-sectional shape of the core 2110, and further improve the output density (smaller size, higher output) and higher efficiency of the motor. The structure can be excellent in cost reduction by reducing the amount of permanent magnets.

In the present embodiment, the core 2110 of the open slot having the same core cross-sectional shape in the direction perpendicular to the rotation axis is shown, but the cross-sectional shape of the core 2110 is at least on the surface facing the rotor 200 (axial end surface). It suffices to have a tapered portion 2111 and a straight portion 2112, and the other portions may have any shape. For example, it may have a semi-closed shape in which the cross-sectional area of the core 2110 is reduced at the center. Further, the laminating direction of the thin plate magnetic material may be the circumferential direction of the rotor, and the core may be composed of a non-laminated body such as a compression molded core obtained by compression molding iron powder, as in other embodiments. Is.

<Summary>
Next, the features and effects included in the present embodiment will be described. The core 2110 according to the present embodiment is formed by laminating rectangular thin plate magnetic materials in the radial direction, and has a trapezoidal portion 2113 which is a trapezoidal pillar and a straight portion 2112 having the lower base of the trapezoid as a long side. It is a trapezoid in which the rectangular portion 2114, which is a rectangular trapezoid having a short side, is combined. Therefore, even if the thickness of the thin magnetic material forming the core 2110 varies, the radial dimension of the core 2110 can be accommodated within a predetermined dimensional error range by adjusting the number of laminated rectangular portions 2114. it can. Further, the core 2110 having the rectangular portion 2114 has a similar projected shape in the axial direction to the permanent magnet 210 having the notch portion 214 as compared with the core 110 of the trapezoidal column as shown in FIG. 1 (b). Therefore, even if the permanent magnet 210 is provided with the notch portion 214 for forming the circumferential reduction portion 211, the amount of magnetic flux passing through the core 2110 is less likely to decrease. Therefore, according to the axial gap type motor 2000 according to the present embodiment, it is possible to suppress variations in motor characteristics due to variations in the cross-sectional shape of the core 2110, and further improve the output density (smaller size, higher output) and higher efficiency of the motor. The structure can be made excellent in cost reduction by reducing the amount of permanent magnets.

[Third Embodiment]
FIG. 3A shows a perspective view and a cross-sectional perspective view of the rotor 3200 of the axial gap type motor 3000 according to the third embodiment of the present invention. Further, FIG. 3B shows an exploded view of the rotor 3200. Here, the configurations other than the rotor 3200 are the same as those of the axial gap type motor 1000 (FIG. 1 (a)) of the first embodiment, and thus are omitted.

As shown in FIG. 3B, each of the plurality of permanent magnets 3210 has an axial reduction in a tapered shape in which the length in the circumferential direction of the base 3220 is reduced toward the stator 100 in the base 3220 axial direction. A portion 3212 is provided. Further, each of the plurality of holding members 3230 has an axially enlarged portion 3232 having a tapered shape in which the length in the circumferential direction of the base 3220 is increased toward the stator 100 side in the axial direction of the base 3220. It is provided. Then, the axially expanding portions 3232 of the two holding members 3230 arranged side by side in the circumferential direction of the base 3220 among the plurality of holding members 3230 are each of the two holding members 3230 of the plurality of permanent magnets 3210. It is in contact with the axially reduced portion 3212 of one permanent magnet 3210 arranged between them.

Further, a hole 3231 is provided in the holding member 3230 at substantially the center in the radial direction of the base 3220, a screw 3240 is inserted into the hole 3231, and a screw 3240 is screwed into the screw hole 3221 formed in the base 3220. By joining, the holding member 3230 and the base 3220 are fastened.

According to the present embodiment, the permanent magnet 3210 is fixed to the base 3220 in a state where the side surface of the axially reducing portion 3212 of the permanent magnet 3210 and the side surface of the axially expanding portion 3232 of the holding member 3230 are in contact with each other. It is possible to prevent the magnet 3210 from scattering in the stator 100 direction. Further, since the holding member 3230 is mechanically fastened to the base 3220 by the screw 3240, the holding member 3230 is firmly held in the radial direction, the circumferential direction, and the axial direction of the base 3220, and the holding strength of the permanent magnet 3210 is improved.

An example in which the holding member 3230 and the yoke base 3220 are fastened by inserting the screw 3240 into the hole 3231 of the holding member 3230 and screwing the screw 3240 into the screw hole 3221 formed in the base 3220. As shown, the holding member 3230 and the yoke base 3220 may be fastened with other fasteners. For example, the holding member 3230 and the yoke base 3220 may be fastened by pouring a liquid resin into the holes provided in the holding member and the base and curing the resin internally by a treatment such as thermosetting. Further, the holding member 3230 and the yoke base 3220 may be fastened by inserting a rivet made of resin or the like into a hole provided in the holding member and the base and crimping the rivet.

As shown in FIG. 3C, the holding member is integrally formed by connecting the holding member base 3233 formed in an annular shape inside the plurality of permanent magnets 3210 arranged in an annular shape and the plurality of holding members 3230. You may. Further, the annular holding member base may be formed on the outside of the plurality of permanent magnets 3210 arranged in the ring instead of the inside.

<Summary>
Next, the features and effects included in the present embodiment will be described. The rotor 3200 according to the present embodiment is provided with a plurality of permanent magnets 3210 provided with an axially reduced portion 3212 having a tapered shape in which the length in the circumferential direction of the base 3220 is reduced toward the stator 100 in the base 3220 axial direction. The plurality of holding members 3230 are provided with an axially enlarged portion 3232 having a tapered shape in which the length of the base 3220 in the circumferential direction is increased toward the stator 100 in the axial direction of the base 3220. Then, the axially expanding portions 3232 of the two holding members 3230 arranged side by side in the circumferential direction of the base 3220 among the plurality of holding members 3230 are each of the two holding members 3230 of the plurality of permanent magnets 3210. It is in contact with the axially reduced portion 3212 of one permanent magnet 3210 arranged between them. Therefore, the permanent magnet 3210 is fixed to the base 3220 in a state where the side surface of the axially reducing portion 3212 of the permanent magnet 3210 and the side surface of the axially expanding portion 3232 of the holding member 3230 are in contact with each other. Therefore, the stator 100 of the permanent magnet 3210 It is possible to prevent scattering in the direction.

Further, since the axially reducing portion 3211 of the permanent magnet 3210 and the circumferentially expanding portion 3231 of the holding member 3230 have a tapered shape, they are easy to make and hard to break. Further, since the circumferential reduction portion 3211 of the permanent magnet 3210 and the circumferential expansion portion 3231 of the holding member 3230 are in surface contact with each other on the tapered surface, they are not easily broken. Further, the holding member 3230 is mechanically fastened to the base 3220 by a screw 3240. Therefore, the permanent magnet 3210 is firmly held in the radial direction, the circumferential direction, and the axial direction. Therefore, this embodiment can improve the holding strength of the permanent magnet 3210.

[Fourth Embodiment]
FIG. 4A is a perspective view of the rotor 4200 of the axial gap type motor 4000 according to the fourth embodiment of the present invention. Here, the configurations other than the rotor 4200 are the same as those of the axial gap type motor 1000 of the first embodiment, and thus are omitted here.

The base 4220 of FIG. 4A has a flange portion 4222 protruding from the outer peripheral portion of the base 4220 toward the permanent magnet 3210 along the rotation axis direction of the rotor 4200. The inner peripheral surface of the flange portion 4222 is in contact with at least a part of the end surface of the base 4220 in the outer radial direction of the permanent magnet 3210.

The effect of the structure according to the present embodiment will be described with reference to FIG. 4 (b). The centrifugal force Fc applied to the permanent magnet 3210 during the operation of the motor 4000 is the reaction force Fr1 from the circumferential expansion portion 231 of the holding member 3230 that comes into contact with the circumferential reduction portion 211 of the permanent magnet 3210, and the base in the permanent magnet 3210. It is held by the reaction force Fr2 from the flange portion 4222 that comes into contact with the end face in the outer radial direction of the 4220. Further, the holding member 3230 is held by a screw 3240 that fixes the holding member 3230 to the base 4220 and a flange portion 4222 that contacts the end face of the base 4220 in the outer diameter direction of the holding member 3230. Therefore, the reaction force Fr1 acting on the circumferential reduction portion 211 of the permanent magnet 3210 from the circumferential expansion portion 231 of the holding member 3230 is dispersed in the reaction force Fr1'from the screw 3240 and Fr1'from the flange portion 4222. That is, the centrifugal force Fc is dispersed in the screw 3240 and the flange portion 4222 to hold the permanent magnet 3210, so that the holding strength is improved. In addition, the collar portion 4222 having a cylindrical inner peripheral surface has a cylindrical surface. Even if the load of the permanent magnet 3210 and the holding member 3230 is applied, the load is dispersed in the circumferential direction without being concentrated on a part of the outer periphery thereof, and the stress concentration on the flange portion 4222 can be suppressed, so that the holding strength can be improved. ..

<Summary>
Next, the features and effects included in the present embodiment will be described. The base 4220 according to the present embodiment also has a flange portion 4222 protruding from the outer peripheral diameter side to the permanent magnet side. Therefore, the permanent magnet 3210 can be held by distributing the force to the circumferentially expanding portion 231 and the flange portion 4222 of the holding member 3230, so that the holding strength can be improved.

[Fifth Embodiment]
FIG. 5A is a perspective view of the rotor 5200 of the axial gap type motor 5000 according to the fifth embodiment of the present invention. Further, FIG. 5B is an exploded view of the rotor 5200. Here, the configurations other than the rotor 5200 are the same as those of the axial gap type motor 1000 of the first embodiment, and thus are omitted here.

The base 5220 of FIG. 5B has a groove 5222 formed in a portion facing the plurality of permanent magnets 210, and as shown in FIG. 5A, has a lower conductivity than the base 5220. The conductive member 5223 is inserted into the groove 5222. The low conductive member 5223 is formed by a roll around which a thin plate magnetic material is wound around a rotation axis.

Further, as shown in FIG. 5B, the holding member 5230 is provided with holes 5231 on the inner side and the outer side in the radial direction of the base 5220, respectively, and screws 5240 are inserted into each of the two holes 5231. The plurality of holding members 5230 are fixed to the base 5220 by screwing the screws 5240 into the screw holes 5221 formed in the base 5220. As a result, the low conductive member 5230 can be held in the groove 5222.

A DC magnetic field is generated in the base 5220 by the permanent magnet 3210, but an alternating magnetic field component depending on the position of the core 2110 is generated in the base 5220 by the interaction with the alternating magnetic field emitted from the stator 100. As a result, an eddy current is generated in the base 5220 so as to cancel the change in the magnetic field. However, in the present embodiment, when the low conductive member 5223 is inserted into the groove 5222 of the base 5220, the resistivity due to the low conductive member 5223 is significantly increased, so that the base is magnetically interacted with the core 2110. The eddy current generated in 5220 is suppressed, and the rotational torque and efficiency can be improved.

Further, the low conductive member 5223 is held in the groove 5222 by fixing the holding member 5230 to the base 5220. Therefore, the cost can be suppressed. In particular, since the end surface of the roll constituting the low conductive member 5230 is a laminated surface of thin plates, it is difficult to apply an adhesive and stable fixing is difficult. However, according to this embodiment, adhesion is not required, and the low conductive member 5230 can be reliably held. The low conductive member 5223 may be formed of a non-laminated body such as a dust core as long as the resistivity increases with respect to the eddy current flowing in the radial direction. Alternatively, instead of winding one magnetic material, a plurality of annular foil bands having different diameters may be arranged concentrically in a concentric circle such as Baumkuchen and laminated in the radial direction.

<Summary>
Next, the action and effect of this embodiment will be described. In the base 5220 according to the present embodiment, a groove 5222 is formed in a portion facing the permanent magnet 3210, and a low conductive member 5223 made of a roll in which a thin plate magnetic material is wound around a rotation axis is inserted. Therefore, since the resistivity of the low conductive member 5223 is significantly increased, the eddy current generated in the base 5220 due to the magnetic interaction with the core 2110 is suppressed, and the rotational torque and efficiency can be improved.

[Sixth Embodiment]
FIG. 6 is an exploded view of the rotor 6200 of the axial gap type motor 6000 according to the sixth embodiment of the present invention. Since the holding member of the rotor 6200 and the structure other than the rotor 6200 are the same as those of the axial gap type motor 1000 of the first embodiment, they are omitted.

The rotor 6200 of FIG. 6 is provided with four convex portions 6215 on the surface of eight permanent magnets 6210 facing the base 6220, and is convex on the disk surface of the base 6220 facing the eight permanent magnets 6210. There are 32 recesses 6224 that fit into the portion 6215. When each of the eight permanent magnets 6210 is arranged on the base 6220, the permanent magnets 6210 are fixed to the base 6220 by inserting and fitting each of the convex portions 6215 into the concave portion 6224.

As a result, the centrifugal force applied to the permanent magnet 6210 is dispersed in the circumferentially expanding portion 231 of the holding member 3230, the flange portion 4222, the convex portion 6215, and the concave portion 6224, further improving the holding strength. Further, since the magnet can be positioned by inserting the convex portion 6215 into the concave portion 6224 at the time of assembly, the work efficiency can be improved.

In this embodiment, an example is shown in which the permanent magnet 6210 for one pole is provided with four convex portions 6215, but at least one convex portion 6210 may be provided. Further, the holding member 3230 may be provided with a convex portion and a concave portion corresponding to the base 6220 may be provided.

<Summary>
Next, the action and effect of this embodiment will be described. In the rotor 6200 according to the present embodiment, at least one convex portion 6215 is provided on the surface of a plurality of permanent magnets 6210 facing the base 6220, and the convex portion 6215 is provided on the disk surface of the base 6220 facing the permanent magnet 6210. A plurality of recesses 6224 are provided to be fitted with. When each of the plurality of permanent magnets 6210 is arranged on the base 6220, the permanent magnets 6210 can be fixed to the base 6220 by inserting each of the at least one convex portion 6215 into the recess 6224 to be fitted. it can. Therefore, the centrifugal force applied to the permanent magnet 6210 is dispersed in the circumferentially expanding portion 231 of the holding member 3230, the flange portion 4222, the convex portion 6215, and the concave portion 6224, and the holding strength is further improved. Further, since the magnet can be positioned by inserting the convex portion 6215 into the concave portion 6224 at the time of assembly, the work efficiency can be improved.

The present invention is not limited to the above-described embodiment, and includes various modifications. For example, the above-described embodiment has been described in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to the one including all the described configurations. Further, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Further, it is possible to add / delete / replace a part of the configuration of each embodiment with another configuration.

The embodiment of the present invention may have the following aspects. In the above embodiment, the rotors 200 are arranged to face each other on both end faces of the stator 100, but a single rotor system is adopted in which the rotor 200 faces only one of the end faces of the two stators 100, and the shaft of the axial air gap type rotary electric machine. The length in the direction may be shortened. Further, although a three-phase power supply is used as the AC power supply, an AC power supply having a different number of phases may be used.

1000, 2000, 3000, 4000, 5000, 6000 ... Axial gap type rotary electric machine (motor), 100 ... Stator, 110, 2110 ... Core, 120 ... Winding, 130 ... Resin, 200, 2200, 3200, 4200, 5200, 6200 ... rotor, 210, 3210, 6210 ... permanent magnet, 211 ... circumferential reduction part, 3212 ... axial reduction part, 220, 3220, 4220, 5220, 6220 ... base, 4222 ... collar part, 5223 ... low conductive member , 230, 3230, 5230 ... Holding member, 231 ... Circumferential expansion part, 3232 ... Axial expansion part, D ... Distance between permanent magnets (between poles)

Claims (15)

In an axial gap type rotary electric machine in which a stator and a rotor face each other through a gap provided along the central axis direction of the rotor.
The rotor is located between a disk-shaped base, a plurality of magnets arranged along the circumferential direction of the base on the disk surface of the base facing the stator, and the plurality of magnets. It has a plurality of holding portions, each of which is arranged and holds the plurality of magnets.
Each of the plurality of magnets has a circumferential reduction portion whose length in the circumferential direction decreases toward the outside in the radial direction of the base.
Each of the plurality of holding portions has a circumferential expansion portion whose length in the circumferential direction of the base increases toward the outside in the radial direction of the base.
The circumferential expansion portions of the two holding portions arranged side by side in the circumferential direction of the base among the plurality of holding portions are respectively arranged between the two holding portions of the plurality of magnets. An axial gap type rotary electric machine characterized in that it is in contact with the circumferential reduction portion of one magnet. The axial gap type rotary electric machine according to claim 1.
The circumferential expansion portion and the circumferential reduction portion have a tapered shape.
Axial gap type rotary electric machine featuring. The axial gap type rotary electric machine according to claim 1.
The circumferential reduction portion is provided outside the radial direction of the base of the permanent magnet.
The circumferential expansion portion is provided outside the radial direction of the base in the holding member.
Axial gap type rotary electric machine featuring. The axial gap type rotary electric machine according to claim 1.
A plurality of cores around which a coil is wound are arranged in a ring shape on the stator.
The shape of the surface of the plurality of cores facing the rotor is a trapezoidal portion in which the length of the stator in the circumferential direction increases toward the outside in the radial direction of the stator, and the stator. The shape is a combination of the base of the trapezoid and the rectangular portion having the same side in the circumferential direction.
Axial gap type rotary electric machine featuring. The axial gap type rotary electric machine according to claim 1.
Each of the plurality of holding portions is provided with an axially expanding portion in which the length in the circumferential direction of the base is increased toward the stator side in the axial direction of the base.
Each of the plurality of magnets is provided with an axial reduction portion in which the length in the circumferential direction of the base is reduced toward the stator side in the axial direction of the base.
The axially enlarged portions of the two holding portions arranged side by side in the circumferential direction of the base among the plurality of holding portions are respectively arranged between the two holding portions of the plurality of magnets. Being in contact with the axial reduction portion of one magnet,
Axial gap type rotary electric machine featuring. The axial gap type rotary electric machine according to claim 5.
The axial expansion portion and the axial reduction portion have a tapered shape.
Axial gap type rotary electric machine featuring. The axial gap type rotary electric machine according to claim 1.
The holding part is molded with a molding resin,
Axial gap type rotary electric machine featuring. The axial gap type rotary electric machine according to claim 7.
That the holding portion covers the magnet.
Axial gap type rotary electric machine featuring. The axial gap type rotary electric machine according to claim 1.
The holding portion is formed by a holding member,
It has a fixing structure for fixing the holding member to the base.
Axial gap type rotary electric machine featuring. The axial gap type rotary electric machine according to claim 1.
A flange portion that protrudes from the outer peripheral portion of the base along the rotation axis direction of the rotor and comes into contact with at least a part of the outer circumference of the magnet is provided on the base.
Axial gap type rotary electric machine featuring. The axial gap type rotary electric machine according to claim 10.
At least a part of the outer circumference of the holding part and at least a part of the inner circumference of the collar part come into contact with each other.
Axial gap type rotary electric machine featuring. The axial gap type rotary electric machine according to claim 1.
A low conductivity member having a lower conductivity than the base is arranged between the base and the magnet.
Axial gap type rotary electric machine featuring. The axial gap type rotary electric machine according to claim 1.
A fixing structure for fixing the plurality of magnets to the base is provided on each surface where the plurality of magnets come into contact with the base.
Axial gap type rotary electric machine featuring. The axial gap type rotary electric machine according to claim 13.
The fixed structure
At least one convex portion provided on each of the plurality of magnets, and a plurality of concave portions provided on the base and fitted to the plurality of convex portions.
Axial gap type rotary electric machine featuring. A stator formed by arranging a core and a coil wound around the core in an annular shape,
A rotor that faces the axial end face of the stator via a gap, is provided.
The rotor has a base and a plurality of magnets annularly arranged on the stator-side end face of the base.
The magnet has a plurality of peripherally expanding portions whose circumferential width expands toward the outside in the radial direction and a circumferentially contracting portion whose circumferential width decreases from the expanding portion toward the outward in the radial direction. An axial gap type rotary electric machine having a holding member in contact with the circumferential side surface of the magnet between the magnets.

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