JP2003332128A - Mold for manufacturing magnet, method for manufacturing magnet, anisotropic magnet, and permanent magnet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mold for manufacturing a magnet that can be made anisotropic so that the void magnetic flux density distribution may form a sine wave as much as possible when used in a motor, superior in shock resistance and can be formed by using a sintered magnet. <P>SOLUTION: When a magnet 11 used in a permanent magnet motor 12 is molded into a segment of one magnetic pole by using a mold, an oriented magnetic field is applied to a magnet material 10 by using a magnetic circuit 6 comprising yokes 1, 4L and 4R that are provided with main magnetic pole surfaces 1e, 4La and 4Ra on the void surface side and both circumferential end surface sides of the magnetic material 10, making the magnet material 10 anisotropic. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention forms a magnet used in a motor so as to form a segment shape for one magnetic pole, and differently converges the magnetic flux in the central portion of the air gap surface facing the armature. TECHNICAL FIELD The present invention relates to a magnet manufacturing die device that is manufactured by squaring, a method for manufacturing a magnet, an anisotropic magnet manufactured by the method, and a permanent magnet motor configured using the magnet.

[0002]

Conventionally, for the purpose of improving the characteristics of a permanent magnet motor, when an orientation magnetic field is applied to a magnet used in the motor to make it anisotropic, the magnet is used as an air gap surface side of the magnet. There has been a method of making a radial anisotropy by arranging magnetic poles on the opposite surface side and setting the former magnetic pole width to be narrower than the latter magnetic pole width. In addition, in the case where the magnet is formed so as to form a ring by itself,
There has been a method in which an even number of magnetic poles are alternately arranged on the air gap surface side of the magnet so that the polarities are different and the leakage magnetic flux between the magnetic poles is used as an orientation magnetic field to make the pole anisotropic.

However, if the magnet is only made to be radially anisotropic by the former method, the oriented magnetic field is formed so that the magnetic flux concentrates near the center of the magnetic pole and radiates from it, so that it was used for the rotor of the motor. In that case, the air gap magnetic flux density distribution was close to a trapezoidal wave shape, and the cogging torque could not be sufficiently suppressed.

When the magnet is formed by itself as in the latter case, it is difficult to form a sintered magnet because impact resistance is lowered because a large number of portions in which the crystal direction turns are generated in the magnet. However, there is a problem that it is limited to the case of using a bond magnet or the like having a plastic as a binder.

The present invention has been made in view of the above circumstances, and an object thereof is to make anisotropic so that the air-gap magnetic flux density distribution when used in a motor is as sinusoidal as possible, and to provide shock resistance. Of good magnetism and capable of being formed even by using a sintered magnet, a magnet manufacturing die device, a method of manufacturing a magnet, an anisotropic magnet manufactured by the method, and a permanent magnet formed by using the magnet. It is to provide a magnet motor.

[0006]

In order to achieve the above object, a magnet manufacturing die apparatus according to a first aspect of the present invention molds a magnet used in a motor to form a segment shape for one magnetic pole, and A magnetic field generating means, an air gap side of a magnet material, and an air gap side and both end sides in the circumferential direction of the magnet material are anisotropically produced so as to converge the magnetic flux in the central portion of the air gap surface facing the armature of the motor. And a magnetic circuit which has a magnetic pole on three sides and is made of a soft magnetic material and which forms a magnetic path of a magnetic field generated by the magnetic field generating means, and applies an orientation magnetic field to the magnet material through the magnetic circuit. It is characterized by making it anisotropic.

According to this structure, when a magnetic flux is generated from the magnetic pole on the air gap side, the magnetic flux passes through the magnet material and then reaches two magnetic poles arranged on both end sides in the circumferential direction. become. That is, the passage of the magnetic flux in the magnet material inevitably exhibits polar anisotropy, and the orientation magnetic field is generated so that the magnetic flux converges on the air gap surface side of the magnet. Therefore, even if the radial thickness of the magnet is uniform, it is possible to make the air gap magnetic flux density distribution anisotropic such that it has a sinusoidal shape. Further, since the magnet is formed in a segment shape, the shock resistance becomes better than that of an integrally molded magnet when used in a motor. In addition, there is no problem in forming using a sintered magnet.

In this case, as described in claim 2, at least the non-magnetic material is arranged between the magnetic pole on the air gap surface side and the magnetic pole on the circumferential end surface side, and the magnet material is made anisotropic and molded. It is preferable to configure as follows. According to this structure, when the magnetic pole on the air gap side and the magnetic pole on the end face in the circumferential direction are formed separately, when the magnet material is molded, the two magnetic poles come into contact with each other to short-circuit the magnetic field. It is possible to prevent this and to use a non-magnetic material as a part of the molding die. Therefore, the degree of freedom of the magnet shape can be further increased.

Further, as described in claim 3, the magnetic field generating means may be constituted by a permanent magnet. That is, since the permanent magnet does not generate heat when a magnetic field is applied, it is possible to suppress the temperature change of the molding die. Therefore, the molding of the magnet can be performed in a stable state.

In this case, as described in claim 4, it is preferable that the permanent magnet is disposed so as to be sandwiched in the soft magnetic material portion forming the magnetic pole on the gap surface side in the vicinity of the magnet material to be molded. According to this structure, it is possible to minimize the leakage magnetic flux to the outside of the magnetic circuit.

Further, as described in claim 5, the magnetic field generating means may be composed of a coil wound around the soft magnetic material and a current source for supplying a current to the coil. According to this structure, the state of the orientation magnetic field applied can be controlled by controlling the amount of current supplied to the coil, and the characteristics of the magnet can be variously changed.

In this case, as described in claim 6, it is preferable that the coil is wound around the soft magnetic material portion forming the air gap side magnetic pole. With this configuration, as in claim 4,
The leakage magnetic flux to the outside of the magnetic circuit can be minimized.

In the above case, as described in claim 7, it is preferable that the circumferential width dimension of the magnetic poles on the air gap side is approximately 1/2 of the magnetic pole pitch. That is, since the magnetic flux necessary for orienting the magnet in the magnetic field is about half of the saturation magnetic flux density, the soft magnetic material will not be magnetically saturated with this configuration.
Further, since the interval between the two facing magnetic poles on the circumferential end surface side corresponds to the magnetic pole pitch, it is possible to prevent the orientation magnetic field from concentrating on the shortest distance portion between the magnetic pole on the air gap surface side and the magnetic pole on the circumferential end surface side. Anisotropy can be better achieved.

Further, as described in claim 8, the shape of the surface of the air gap surface side magnetic pole facing the magnet material is such that the distance from the magnet material is the shortest in the center portion and both ends from the center portion. It is good to form so that it gradually becomes longer over
Specifically, for example, as described in claim 9, the shape is defined by two planes in which the line of intersection of the two is located in the central portion, a cylindrical surface,
It may be formed to have either an elliptic cylindrical surface or a parabolic surface. According to this structure, by further concentrating the orientation magnetic field in the central portion of the magnet material, the air gap magnetic flux density distribution can be made closer to a sine wave shape.

Further, in the above case, as described in claim 10, the circumferential end face side magnetic pole is configured such that its radial dimension is longer than the radial dimension of the circumferential end face of the magnet material. The orientation magnetic field may be applied in a state where the gap side ends of the magnet material and the circumferential direction end face side magnetic poles are aligned.

That is, since the magnetic flux generated from the magnetic poles on the air gap side tends to spread radially toward the magnetic poles on the circumferential end face side, when the magnetic material and the circumferential end face magnetic poles have the same radial dimension, There is a possibility that a minor loop may be formed in which the magnetic field lines that have once passed through the magnet material pass through the magnet material again. Further, when the amount of magnetic flux generated by the magnetic field generating means is excessive as compared with the magnetic pole cross-sectional area, this tendency is promoted. Therefore, according to the tenth aspect, it is possible to prevent the formation of a minor loop of magnetic force lines, and it is easy to control the amount of magnetic flux generated by the magnetic field generating means.

Further, as described in claim 11, the shape of the magnetic poles on the end face in the circumferential direction may be formed such that the facing distance between the two magnetic poles becomes longer as the distance from the air gap face becomes closer. According to this structure, the end face in the circumferential direction of the magnet is formed so as to be inclined with respect to the direction of the magnetic pole on the air gap side, so that the magnetic force lines generated from the magnetic pole on the air gap side make the end face in the circumferential direction more uniform. It will pass through in a distributed state. Therefore, the magnet can be made anisotropic better.

According to the magnet manufacturing method of the twelfth to twenty-second aspects, it is possible to obtain the same effects as those of the magnet manufacturing die apparatus of the first to eleventh aspects.

According to the twenty-third aspect of the present invention, since the anisotropic magnet is manufactured by the magnet manufacturing die apparatus according to any one of the first to eleventh aspects, it has a high magnetic flux density when used in a motor. It is possible to generate magnetism and improve the characteristics of the motor. Alternatively, motors having the same characteristics can be made smaller.

In this case, as described in claim 24,
The shape of the air gap surface may be formed such that the air gap length with the armature is the shortest at the center of the magnetic pole and becomes longer toward both end surfaces in the circumferential direction. Specifically, as described in claim 25, It is advisable to form the void surface so as to form a cylindrical surface.
According to this structure, since the magnetic flux density gradually decreases from the central portion of the magnet to both end faces in the circumferential direction, the air gap magnetic flux density distribution can be further approximated to a sine wave shape.

Further, when the thickness of the magnet in the radial direction is substantially uniform, the path length through which the magnetic flux generated from the end of the air gap side magnetic pole passes through the inside of the magnet is the magnetic flux generated from the central portion. It will be shorter in comparison. For this reason, the demagnetization proof stress is weak and the contribution rate to the field is low in this portion.
Therefore, according to the twenty-fourth aspect, it is possible to suppress the fluctuation of the magnetic flux amount.

According to a twenty-sixth aspect of the permanent magnet motor, a plurality of anisotropic magnets according to any of the twenty-third to twenty-fifth aspects are arranged in a substantially annular shape, and a field magnet for rotating the rotor. Since the field generating means for generating is generated, a highly efficient motor can be obtained.

In this case, as described in claim 27,
It is preferable that the anisotropic magnet is made of a neodymium-based material and that the radial thickness t of the frame holding the anisotropic magnet is t <L / 4, where L is the magnetic pole pitch. . That is, the magnetic flux generated from the magnetic pole on the air gap side is divided into two toward the two opposing magnetic poles on the end face in the circumferential direction with a space corresponding to the magnetic pole pitch L. The amount of magnetic flux that can pass through the radial portion of the frame is about 1 /
Since it is about 2, it is possible to reduce the size and weight of the motor by setting the radial thickness t in this way.

When the anisotropic magnet is made of a ferrite material as described in claim 28, the radial thickness t of the frame holding the anisotropic magnet is set to L and the magnetic pole pitch is set to L. Then, you may form so that it may be set to t <L / 8. That is, when the magnet of the ferrite material is used, the saturation magnetic flux density is about 1/3 of that of the neodymium material. It can be made smaller and lighter.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment) A first embodiment of the present invention will be described below with reference to FIGS.
FIG. 1 shows the structure of a mold device for molding a magnet used for a motor by a wet ferrite material for one magnetic pole (one segment) and for anisotropically applying an orientation magnetic field.

A yoke 1 made of iron as a soft magnetic material
Has the circuit connecting portions 1b and 1c at both ends of the base portion 1a, and has the air gap surface side magnetic pole portion 1d at the central portion, and has a substantially E-shaped cross section. The shape of the tip of the air gap surface side magnetic pole portion (air gap surface side magnetic pole) 1d is formed as a main magnetic pole surface 1e so as to form a cylindrical surface smoothly connected to the side surface. Also,
A coil (magnetic field generating means) 2 for generating a magnetic field is wound around the air gap side magnetic pole portion 1d. A direct current power source (current source, magnetic field generating means) is used to generate an orientation magnetic field in the coil 2.
Power is supplied by means of 3.

Above the circuit connecting portions 1b and 1c in FIG.
Yokes (circumferential end face side magnetic poles) 4L and 4R made of iron and having a rectangular cross section are arranged. These two yokes 4L and 4R are arranged with an interval corresponding to the magnetic pole pitch L when magnets molded as described later are incorporated in the motor, that is, they are arranged opposite to each other with a magnet filling space 5 in between. There is. In addition, the width dimension of the air gap surface side magnetic pole portion 1d is
It is set to be about 1/2 of the magnetic pole pitch L.
The yokes 1 and 4L, 4R form a magnetic circuit 6.

Yoke 1 and coil 2 and yokes 4L and 4R
A non-magnetic mold 7 made of stainless steel, which is a non-magnetic material, is disposed between the magnet filling space 5 and the magnet filling space 5. The non-magnetic mold 7 prevents the magnetic pole portion 1d on the air gap side of the yoke 1 from coming into contact with the yokes 4L and 4R and magnetically short-circuited, and is filled in the magnet filling space 5 to be molded. Used to shape the shape of the magnet on the air gap side. Therefore, the portion of the nonmagnetic die 7 desired in the magnet-filled space 5 has a shape that draws a gentle arc that is convex upward.

Mold plates 8L, 8R made of stainless steel are arranged above the yokes 4L, 4R, and these mold plates 8L, 8R are vertically displaced by a drive mechanism (not shown). It is configured. Further, a press die body 9 made of stainless steel is arranged above the magnet filling space 5. The press die body 9 is also configured to be displaced in the vertical direction by a drive mechanism (not shown), and acts to apply pressure to the magnet material filled in the magnet filling space 5.

The radial dimensions of the yokes 4L and 4R are set so as to overhang by about 20% with respect to the radial dimensions of the magnet in the final molded shape. Also, the yoke 4
The surfaces of L and 4R facing each other are the main magnetic pole surfaces 4La and 4R.
1a, the magnetic pole surface is provided with a draft of about 1 degree with respect to the vertical direction in FIG. 1 as shown in a partially enlarged view in FIG.

If, for example, 24 magnets molded by the mold device having the above-mentioned structure are arranged on the rotor side of the outer motor, the magnetic pole pitch will be 7.5 degrees. Since the main magnetic pole surfaces 4La and 4Ra of 4L and 4R are provided with a draft, the shape of the magnet is formed so as to be slightly divergent.

Next, the operation of this embodiment will be described with reference to FIGS. The magnet filling space 5 of the mold apparatus is filled with a wet ferrite material having a magnetic powder of, for example, iron oxide and strontium, as the magnet material 10. Then, the coil 2 is energized by the DC power source 3 to apply an orientation magnetic field to the magnet material 10, and at the same time, the press die 9 is pressed.
By applying pressure from above, the magnet is molded.

FIG. 2 shows the state of magnetic force lines of the orientation magnetic field applied to the magnet material by the die device (the coil 2 is not shown). That is, some of the magnetic force lines output from the magnetic pole portion 1d on the air gap side of the yoke 1 pass through the magnet material 10 from the air gap side, and then the main magnetic pole surface 4 of the yokes 4L, 4R.
Head towards La, 4Ra. By applying such an orientation magnetic field, the magnetic flux density in the central portion of the magnet becomes maximum, and the magnetic flux density decreases from that point toward both end surfaces in the circumferential direction. That is, the magnet material 10 exhibits a tendency of becoming anisotropic by applying such an orientation magnetic field.

FIG. 3 shows an example of the air gap magnetic flux density distribution of the magnet actually molded by the mold device. The abscissa represents the circumferential position with both ends of the magnet as mechanical angles of 0 ° and 180 °, and the ordinate represents the relative level of the magnetic flux density normalized with the residual magnetic flux density of ferrite being “1”. That is, the magnetic flux density of the magnet shown by the solid line shows a distribution state extremely close to the sine wave shown by the broken line.

Here, the radial dimension of the yokes 4L and 4R is 2 with respect to the radial dimension of the final molded shape of the magnet.
The reason why the projection is set to be relatively large will be described with reference to FIG.

The magnetic flux generated from the air gap side magnetic pole portion 1d tends to spread radially toward the main magnetic pole surfaces 4La and 4Ra. Therefore, as shown in FIG. 4, the yokes 4L and 4R are
If the radial dimension of the magnet is the same as the final radial dimension of the magnet, the magnetic force line B1 generated so as to penetrate through the center of the air gap surface side magnetic pole portion 1d and, for example, the main magnetic pole surface 4R after passing through the magnet once.
Line B of magnetic force recovered by the magnetic pole portion 4Ra from the boundary with a.
Between 2 and 2, a minor loop Bm of magnetic force lines is formed in which the magnetic flux that once passed through the magnet passes through the magnet again.

The above tendency is also promoted when the amount of magnetic flux generated by the coil 2 is excessive compared to the magnetic pole cross-sectional area. Therefore, by setting the radial dimension of the yokes 4L and 4R to be larger than the final radial dimension of the magnet, it is possible to prevent the formation of a minor loop of the magnetic flux and to reduce the amount of the magnetic flux generated by the coil 2. Easy to control.

Further, when an anisotropic magnet is used in a rotor of a motor as described later, it is necessary to secure a magnetic path for adjacent magnetic poles in a rotor frame (back yoke) for holding the magnet. For the purpose, it is not necessary to give a predetermined wall thickness dimension (cross-sectional area), and the dimension may be set only when it is necessary to ensure mechanical strength.

However, even in this case, considering that the rotor frame having the dimension set as described above is used as a magnetic path as much as possible, as shown in FIG. 2, the magnetic force lines passing through the magnet are bent substantially at right angles. Anisotropy is preferably performed toward the main magnetic pole surface 4La.

In FIG. 5, after the magnet 11 is molded by the mold device, the magnet 11 separated from the mold is heated at a predetermined temperature to be sintered, and the magnet 11 is completed by a polishing process.
1 shows a configuration of an outer rotation type permanent magnet motor 12 configured by using the. The 24 magnets 11 are 1.6 mm thick S
It is held on the inner peripheral portion of a rotor frame 13 formed by drawing PCC, and has a rotor (field generating means) 14
Is configured. The rotor 14 has a rotating shaft (not shown) rotatably supported by the housing of the motor 12 through a mechanism such as a bearing.

On the inner peripheral side of the rotor 14, a stator (armature) 15 is arranged with the magnet 11 having a predetermined gap. As for the stator 15, the surface of a stator core 16 formed by punching a silicon steel plate and laminating a plurality of sheets and then caulking the same is coated with an insulator 17 such as PET resin, and the stator poles are provided on each convex pole portion. It is configured by winding the winding 18.

The radial thickness t of the rotor frame 13 is 1.6 mm as described above, and this dimension t is set so that t <L / 8 with respect to the magnetic pole pitch dimension L. ing. This dimension setting is determined as follows. That is, since the magnet 11 is made extremely anisotropic, the rotor frame 13 almost does not have a role of forming a part of a magnetic circuit for passing a field magnetic flux. Therefore, it is preferable that the wall thickness t of the rotor frame 13 is set to be as thin as possible while ensuring necessary strength.

The magnetic flux generated from the air gap side magnetic pole portion 1d is divided into two main magnetic pole surfaces 4La and 4Ra facing each other with an interval corresponding to the magnetic pole pitch L. Here, if the magnet material is neodymium, for example, the amount of magnetic flux that can pass through the radial portion of the rotor frame 13 is about half that amount. On the other hand, when the ferrite material is used as in this embodiment, the magnetic flux amount is about 1/3 of that of the neodymium material, so that t <L / 8 is set in consideration of structural strength. Is set to.

In the permanent magnet motor 12 configured as described above, since the air gap magnetic flux density distribution of the magnet 11 is substantially sinusoidal, cogging torque is not generated when the motor 12 rotates, and a low level is obtained. It is possible to drive with vibration and low noise. Its high quietness is
For example, it is suitable for a washing tub of a washing machine, a dehydration layer, or a motor for rotating a stirring blade.

According to the experimental results by the inventor of the present invention,
When magnets having the same magnetic properties (but having radial anisotropy) for the same purpose are used, even if the laminated thickness of the iron core is reduced by 20%, the same motor output characteristics as before can be obtained. did it. Further, since the conventional magnet 11 has radial anisotropy, the thickness of the back yoke arranged on the outer peripheral side of the magnet 11 is 3.2 mm because it is necessary to secure a cross-sectional area as a magnetic circuit. In the motor 12 of this embodiment, the radial thickness t of the rotor frame 13 is 1 /
2, which is 1.6 mm. Therefore, the motor 12 can be significantly reduced in size and weight.

As described above, according to the present embodiment, when the magnet 11 used in the permanent magnet motor 12 is formed into a segment shape for one magnetic pole by the mold device, the void surface of the magnet material 10 is formed. Of the yokes 1, 4L, 4 having main magnetic pole surfaces 1e, 4La, 4Ra on the three sides, i.e., on both sides and in the circumferential direction on both ends.
By applying an orientation magnetic field to the magnet material 10 by the magnetic circuit 6 composed of R, the magnet 11 is made to exhibit a polar anisotropy tendency. Therefore, the air gap magnetic flux density distribution of the magnet 11 can be efficiently anisotropicized so as to have a sinusoidal shape.
Further, it is possible to secure sufficient impact resistance as compared with a rotor magnet integrally formed in an annular shape.

Then, the magnetic pole portion 1d on the gap surface side and the yoke 4
Since the magnet material 10 is anisotropically formed and molded while the non-magnetic die 7 is arranged between L and 4R,
When molding the magnet 11, the magnetic pole portion 1d and the yokes 4L, 4
It is possible to prevent a magnetic short circuit due to contact with R. Since the shape of the magnet 11 can be determined by the shape of the non-magnetic die 7, the degree of freedom in shape can be further increased.

Further, the magnetic field generating means is used as the magnetic pole portion 1 on the air gap surface side.
Since the coil 2 wound around the coil d and the DC power supply 3 for supplying current to the coil 2 are used, the state of the applied orientation magnetic field is controlled by controlling the amount of current supplied to the coil 2. Thus, the characteristics of the magnet 11 can be changed in various ways. In addition, if the polarity of the current supplied to the coil is reversed after the magnet 11 is formed, the magnet 11 can be easily separated from the mold. Since the coil 2 is wound around the magnetic pole portion 1d on the air gap surface side, it is possible to minimize the leakage magnetic flux to the outside of the magnetic circuit 6.

Further, the circumferential width of the air gap side magnetic pole portion 1d is set to 1/2 of the magnetic pole pitch L. That is, the magnetic flux necessary to orient the magnetic field of the magnet 11 is about half of the saturation magnetic flux density, and for example, even if the magnetic material is iron, it is 1 T or less at most. No magnetic saturation. Further, two main magnetic pole surfaces 4La and 4Ra facing each other are provided.
Since the interval of is equivalent to the magnetic pole pitch L, the orientation magnetic field can be prevented from concentrating on the shortest distance portion between the magnetic pole portion 1d and the yokes 4L and 4R, and the magnet 11 can be made anisotropic more effectively. .

Further, the shape of the magnetic pole portion 1d on the air gap surface side is specifically designed so that the distance from the magnet material 10 is shortest in the central portion and gradually increases from the central portion to both end portions. Since it was formed to be a cylindrical surface,
By making the orientation magnetic field more concentrated in the central portion of the magnet 11 to make it anisotropic, the air gap magnetic flux density distribution can be made closer to a sinusoidal shape.

The main magnetic pole surfaces 4La and 4Ra are arranged such that the radial dimension of the main magnetic pole surfaces 4La and 4Ra is longer than the radial dimension of the end surface of the magnet 11 in the circumferential direction.
Since the orientation magnetic field is applied in a state where the end portion on the air gap side of 4Ra is matched, the formation of a minor loop of magnetic flux can be prevented, and the control of the amount of magnetic flux generated by the coil 2 is facilitated.

Furthermore, by giving a draft of 1 degree to the main magnetic pole surfaces 4La and 4Ra, the shape is changed to two magnetic pole portions 4.
Since the facing distances of La and 4Ra are formed so as to be closer to the air gap surface side, the magnetic force lines generated from the air gap surface side magnetic pole portion 1d pass through the circumferential end surface in a more uniform distribution state. Therefore, the magnet 11 can be more anisotropically formed.

Since the magnets 11 are arranged in a substantially annular shape to constitute the rotor 14 of the permanent magnet motor 12, it is possible to generate a field with a high magnetic flux density.
It is possible to improve the characteristics of No. 2 and obtain the highly efficient motor 12. Alternatively, motors having the same characteristics can be made smaller.

When the magnet 11 is made of a ferrite material and the radial thickness t of the rotor frame 13 holding the magnet 11 is the magnetic pole pitch L, t <L
Since it is formed to be / 8, the motor can be made sufficiently small and lightweight.

(Second Embodiment) FIGS. 6 and 7 show a second embodiment of the present invention, in which the same parts as those in the first embodiment are designated by the same reference numerals and their description is omitted. Only the part will be described. The magnet 21 in the second embodiment has a first orientation magnetic field applied by the die device at the time of molding.
This is the same as the embodiment, but the shape of the air gap surface of the magnet 21 is different from that of the magnet 11, and constitutes the rotor 14A.
The motor having the rotor 14A constitutes the permanent magnet motor 12A.

As shown in FIGS. 6 and 7, the shape of the air gap surface of the magnet 21 is a cylindrical surface that is convex toward the stator 14, that is, the air gap length is shortest at the center of the magnetic pole. ,
It is formed so as to become longer toward both end faces in the circumferential direction. According to this structure, the magnetic flux density gradually decreases from the central portion of the magnet 21 to both end faces in the circumferential direction, so that the air gap magnetic flux density distribution can be made closer to a sinusoidal shape.

When the radial thickness of the magnet 21 is substantially uniform, the path length through which the magnetic lines of force generated from the ends of the magnetic poles on the air gap side pass through the inside of the magnet 21 is generated from the central portion. Shorter than magnetic lines of force. For this reason, the demagnetization proof stress is weak and the contribution rate to the field is low in this portion. Therefore, if it is configured as in the second embodiment, it is possible to suppress the fluctuation of the magnetic flux amount.

(Third Embodiment) FIG. 8 shows a third embodiment of the present invention. The same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted. Only the different parts will be described below. explain. In the mold apparatus according to the third embodiment, instead of the coil 2 and the DC power source 3, a permanent magnet 22 is used as a magnetic field generating means.
Is used. That is, as shown in FIG. 8, the permanent magnet 22 is arranged so as to be sandwiched between the magnetic pole portion 1d on the air gap side of the yoke 1 and near the tip thereof.

According to the third embodiment configured as described above, since the permanent magnet 22 does not generate heat unlike the coil 2 when a magnetic field is applied, the temperature change of the molding die can be suppressed. it can. Therefore, the molding of the magnet 11 can be performed in a stable state. Further, since the permanent magnet 22 is arranged so as to be sandwiched by the air gap surface side magnetic pole portion 1d in the vicinity of the magnet 11 to be molded, the leakage magnetic flux to the outside of the magnetic circuit can be minimized.

The present invention is not limited to the embodiments described above and shown in the drawings, and the following modifications or expansions are possible. The non-magnetic material disposed between the air gap side magnetic pole and the circumferential end surface magnetic pole may be at least disposed so as to prevent a magnetic short circuit between them, and all non-magnetic materials such as the non-magnetic die 7 are not necessarily magnetic. The material is not limited to one made of wood. The circumferential width of the magnetic pole on the air gap side is not necessarily about 1/2 of the magnetic pole pitch as long as the anisotropy of the magnet can be sufficiently achieved.
You don't have to. The shape of the tip of the magnetic pole on the air gap side is not limited to a cylindrical surface, but in addition, such as two planes where the line of intersection of the two is located in the center, an elliptic cylindrical surface or a parabolic surface It suffices that the distance between them is shortest in the central portion and gradually increases from the central portion to both end portions. Further, as long as the magnet can be sufficiently anisotropic, it is not necessary to limit to these shapes.

If the minor loop of the magnetic flux does not cause any particular problem, or if the setting and management of the magnetic flux amount is sufficiently possible, the radial dimension of the magnetic poles on the circumferential end face side is the same as the radial dimension on the circumferential end face of the magnet. May be. A draft may be imparted to the magnetic pole surface of the magnetic poles on the circumferential end surface side as necessary, and the magnetic pole surfaces facing each other between the two magnetic poles may be parallel to each other, or the magnet may be an abduction motor. When it is used for the rotor, it may be formed so that the facing interval becomes shorter as it approaches the gap surface side. When the anisotropic magnet is made of a neodymium-based material, it is preferable to form the radial thickness t of the rotor frame so that t <L / 4. That is, the magnetic force lines generated from the air gap side magnetic pole can be bisected toward two opposing circumferential direction end surface side magnetic poles with a space corresponding to the magnetic pole pitch L, and can also pass through the radial portion of the frame. Since the amount of magnetic flux is about ½ of that amount, by setting the radial thickness t in this way, the motor can be made smaller and lighter.

As the magnet material, in addition to the above, it is possible to apply to all those which form a sintered anisotropic magnet such as dry ferrite and rare earths such as neodymium. It can also be applied to anisotropic bonded magnets molded by injection molding or compression molding. The permanent magnet motor is not limited to the outer rotation type and may be the inner rotation type.

[0063]

According to the mold device for magnet production and the method for producing magnets of claim 12, the magnet used in the motor has three sides, that is, the air gap surface side and the circumferential end surface sides. Since a magnetic circuit composed of a soft magnetic material having magnetic poles makes the magnet material anisotropic by applying an orientation magnetic field,
Even if the radial thickness of the magnet is uniform, it is possible to make the air gap magnetic flux density distribution anisotropic such that it has a sinusoidal shape. Further, since the magnet is molded so as to form a segment shape for each magnetic pole, it is possible to sufficiently secure impact resistance. In addition, there is no problem in forming using a sintered magnet.

According to the twenty-third aspect of the anisotropic magnet, since the anisotropic magnet is produced by the magnet producing die apparatus of the first aspect, the magnetic field with a high magnetic flux density can be obtained when used in a motor. It is possible to generate magnetism and improve the characteristics of the motor. Alternatively, motors having the same characteristics can be made smaller.

According to a twenty-sixth aspect of the permanent magnet motor, a plurality of anisotropic magnets according to any of the twenty-third to twenty-fifth aspects are arranged in a substantially annular shape, and a field magnet for rotating a rotor is provided. Since the field generating means for generating is generated, a highly efficient motor can be obtained.

[Brief description of drawings]

FIG. 1A is a first embodiment of the present invention, in which FIG. 1A shows a structure of a mold device for molding a magnet used for a motor for one magnetic pole and for anisotropically applying an orientation magnetic field. Figure showing,
(B) is an enlarged view of a part of (a).

FIG. 2 is a diagram showing a state of magnetic force lines of an orientation magnetic field applied to a magnet material by a mold device.

FIG. 3 is a diagram showing an example of a void magnetic flux density distribution of a magnet actually molded by a mold device.

FIG. 4 is a view corresponding to FIG. 2 when the radial dimension of the yoke is the same as the final radial dimension of the magnet.

FIG. 5 is a diagram showing a configuration of an abduction-type permanent magnet motor configured by using magnets molded by a mold device.

FIG. 6 is a view corresponding to FIG. 5 showing a second embodiment of the present invention.

FIG. 7 is a diagram showing only part of the arrangement of magnets on the inner peripheral side of the rotor.

FIG. 8 is a diagram corresponding to FIG. 1 showing a third embodiment of the present invention.

[Explanation of symbols]

1d is a magnetic pole portion on the air gap side (magnetic pole on the air gap side), 2 is a coil (magnetic field generating means), 3 is a DC power source (current source, magnetic field generating means), 4L and 4R are yokes (magnetic poles on the end surface in the circumferential direction), 6 Is a magnetic circuit, 7 is a non-magnetic die (non-magnetic material), 10 is a magnet material, 11 is a magnet (anisotropic magnet), 12 and 12A are permanent magnet motors, 13 is a rotor frame, and 14 and 14A are rotors. (Field generating means), 15 is a stator (armature), 16 is a stator core, 18 is a stator winding, 21 is a magnet, and 22 is a permanent magnet.

Claims (28)

[Claims] 1. A magnet used in a motor is formed to have a segment shape for one magnetic pole, and is anisotropically formed so that the magnetic flux is converged at the central portion of the air gap surface facing the armature of the motor. A mold device for manufacturing a magnet for manufacturing, comprising magnetic field generating means, soft magnetic material having magnetic poles on three sides of a gap surface side of magnet material and both end surfaces in the circumferential direction, and the magnetic field generating means. And a magnetic circuit forming a magnetic path of a magnetic field generated by the means, wherein the magnet material is made anisotropic by applying an orientation magnetic field to the magnet material via the magnetic circuit. 2. A magnet material is anisotropically shaped and molded with at least a non-magnetic material disposed between the air gap side magnetic pole and the circumferential end surface side magnetic pole.
The mold device for manufacturing a magnet as described. 3. The magnet manufacturing die apparatus according to claim 1, wherein the magnetic field generating means is constituted by a permanent magnet. 4. The mold apparatus for magnet manufacturing according to claim 3, wherein the permanent magnet is arranged so as to be sandwiched in a soft magnetic material portion forming a magnetic pole on the air gap side in the vicinity of a magnet material to be molded. . 5. The magnet according to claim 1, wherein the magnetic field generating means includes a coil wound around the soft magnetic material and a current source for supplying a current to the coil. Manufacturing mold equipment. 6. The mold apparatus for manufacturing a magnet according to claim 5, wherein the coil is wound around a soft magnetic material portion forming a magnetic pole on the air gap side. 7. The width dimension in the circumferential direction of the magnetic poles on the gap surface side is approximately ½ of the magnetic pole pitch.
The mold apparatus for manufacturing a magnet according to any one of 1. 8. The shape of the surface of the air gap surface side magnetic pole facing the magnet material is such that the distance from the magnet material to be molded is the shortest in the center portion and gradually increases from the center portion to both end portions. It is formed, The metal mold | die apparatus for magnet manufacture in any one of Claim 1 thru | or 7 characterized by the above-mentioned. 9. The shape of the surface of the magnetic pole on the side of the air gap surface facing the magnet material is formed so that the line of intersection thereof is either a two-plane surface, a cylindrical surface, an elliptic cylindrical surface or a parabolic surface. The mold apparatus for manufacturing a magnet according to claim 8, wherein the mold apparatus is a magnet. 10. The circumferential end face side magnetic poles are configured such that the radial dimension thereof is longer than the radial dimension of the magnetic material to be molded on the circumferential end face, and the magnetic material and the circumferential end face side magnetic poles. The mold apparatus for magnet production according to any one of claims 1 to 9, which is configured to apply an orientation magnetic field in a state where the gap side ends of the magnet are aligned. 11. The shape of the magnetic pole on the circumferential end surface side is formed such that the facing distance between the two magnetic poles becomes longer as the distance between the two magnetic poles approaches the air gap surface side. The mold device for manufacturing a magnet as described. 12. A magnet used in a motor is molded to form a segment shape for one magnetic pole, and is made anisotropic so as to converge the magnetic flux at the center of the air gap surface facing the armature of the motor. A magnetic circuit comprising a soft magnetic material having magnetic poles on three sides of a gap surface side of a magnet material and both end surfaces in the circumferential direction, and forming a magnetic path of a magnetic field generated by a magnetic field generating means. A method of manufacturing a magnet, characterized in that an anisotropic magnetic field is applied to a magnet material through a magnet to make the magnet anisotropic. 13. The magnet material is anisotropically shaped and molded in a state in which a non-magnetic material is disposed at least between the air gap side magnetic pole and the circumferential end surface side magnetic pole. Magnet manufacturing method. 14. The method for producing a magnet according to claim 12, wherein a permanent magnet is used as the magnetic field generating means. 15. The method for producing a magnet according to claim 14, wherein the permanent magnet is disposed so as to be sandwiched in a portion of the soft magnetic material forming the magnetic pole on the air-gap surface side in the vicinity of the magnet material to be molded. 16. A magnet according to claim 12, wherein a coil wound around a soft magnetic material and a current source for supplying a current to the coil are used as the magnetic field generating means. Production method. 17. The method for manufacturing a magnet according to claim 16, wherein the coil is wound around a soft magnetic material portion forming a magnetic pole on the air gap side. 18. The method for producing a magnet according to claim 12, wherein the circumferential width of the air gap side magnetic pole is approximately 1/2 of the magnetic pole pitch. 19. The magnetic pole on the side of the air gap surface is formed such that the distance from the magnet material to be molded is the shortest in the central portion and gradually increases from the central portion to both end portions. The method for manufacturing a magnet according to claim 12. 20. The shape of the surface of the magnetic pole on the air gap side facing the magnet material is formed so that the line of intersection of the magnetic pole and the magnetic pole is either a biplanar surface, a cylindrical surface, an elliptic cylindrical surface or a parabolic surface located in the central portion. 20. The method for manufacturing a magnet according to claim 19, wherein: 21. The radial dimension of the surface of the circumferential end face side magnetic pole facing the magnet material is made longer than the radial dimension of the molded magnet material at the circumferential end face to form the magnet material and the circumferential end face side magnetic pole. 21. The method for producing a magnet according to claim 12, wherein the orientation magnetic field is applied in a state where the ends on the gap side are aligned. 22. The shape of the magnetic poles on the circumferential end surface side is formed such that the facing distance between the two magnetic poles becomes longer as the distance between the two magnetic poles becomes closer to the air gap surface side. Magnet manufacturing method. 23. An anisotropic magnet manufactured by the magnet manufacturing die apparatus according to any one of claims 1 to 11. 24. The shape of the air gap surface is formed such that the air gap length with the armature is the shortest at the center of the magnetic pole, and becomes longer toward the both end surface sides in the circumferential direction. The anisotropic magnet described. 25. The anisotropic magnet according to claim 24, wherein the void surface is formed so as to form a cylindrical surface. 26. A field generating means for generating a field for rotating a rotor by arranging a plurality of anisotropic magnets according to claim 23 in a substantially annular shape. A permanent magnet motor characterized in that 27. The anisotropic magnet is made of a neodymium-based material, and a radial thickness t of a frame holding the anisotropic magnet is
27. The permanent magnet motor according to claim 26, wherein when the magnetic pole pitch is L, t <L / 4. 28. The anisotropic magnet is made of a ferrite material, and the radial thickness t of the frame holding the anisotropic magnet is
27. The permanent magnet motor according to claim 26, wherein when the magnetic pole pitch is L, t <L / 8.