JP6840425B2 - Magnetic drive and its manufacturing method. - Google Patents

Description

The present invention relates to a magnetic drive device using a solid magnet having no holes and a method for manufacturing the same.

Patent Document 1 describes an invention relating to a linear actuator which is a magnetic driving device.

In this linear actuator, a plurality of ring-shaped permanent magnets are axially combined and fixed to a mover shaft made of a ferromagnetic material. The individual magnets are magnetized in the radial direction, but the inner and outer peripheral surfaces of adjacent permanent magnets are magnetized on different magnetic poles. A coil yoke and a coil located inside the coil yoke are provided on the outside, and the permanent magnet is movable in the axial direction in the winding space of the coil. A plurality of coils are provided according to the number of permanent magnets, and the winding directions of adjacent coils are opposite to each other.

The linear actuator is hardly affected by the manufacturing variation of the permanent magnet and the change of the surrounding environment, and can reduce the variation of the thrust.

Patent Document 2 describes an invention relating to a vibration generator which is a magnetic drive device.
This vibration generator is provided with an oscillator facing the coil. A plate-shaped magnet is fixed to the yoke of the vibrator, and the magnet faces the coil. In the magnet, the main magnetic pole and the sub magnetic pole are arranged alternately in the vibration direction. The main magnetic poles are magnetized in the direction orthogonal to the vibration direction, the sub magnetic poles are magnetized in the vibration direction, and these magnetic poles have a so-called Halbach array.

According to the present invention, by arranging the magnetic poles of the magnets in a Halbach array, the magnetic flux density across the coil is increased, and a small size and a large vibration amount can be obtained.

Japanese Unexamined Patent Publication No. 2006-28033 Japanese Unexamined Patent Publication No. 2014-0232338

The permanent magnet used in the linear actuator described in Patent Document 1 has a ring shape, but since the coercive force of the magnet depends on its volume, the volume of the ring-shaped magnet is smaller than the external dimensions. , There is a limit to increasing the strength of the generated magnetic flux.

Further, in order to magnetize a ring-shaped magnet in the radial direction, it is usually necessary to manufacture a semi-ring-shaped magnet and bond it together, which complicates the manufacturing process. Further, when a semi-ring-shaped magnet is joined and used, there is a drawback that magnetic flux loss occurs in the joining gap.

The magnet used in the vibration generator described in Patent Document 2 needs to join the main magnetic poles and the sub-magnetic poles having different magnetizing directions, but the adjacent main magnetic poles and the sub-magnetic poles have a joining surface. Because they repel each other, the joining work becomes very difficult.

The present invention solves the above-mentioned conventional problems, and is capable of performing high-power magnetic drive by increasing the generated magnetic flux density by using a solid magnet having no holes. It is an object of the present invention to provide an apparatus and a method for manufacturing the apparatus.

The present invention provides a magnetic drive having a coil, a freely movable portion moves in the winding space of the coil, and a magnet provided on the movable portion,
Said magnet is formed of a solid magnetic block, possess a first end face and second end surfaces parallel to each other, a coil opposing sides extending the perpendicular direction of the end faces, of the coil opposite sides Almost the entire surface and the first end face and the second end face are magnetized in opposite polarities .
In the movable portion, the first end surface and the second end surface of the magnet are directed in the moving direction, and the direction of the winding shaft of the coil facing the outside of the coil facing side surface and the moving direction are Match and
The movable portion is moved by an electromagnetic force generated by a magnetic flux formed between the first end face and the second end face and the side surface facing the coil and crossing the coil, and a current flowing through the coil. It is a feature.

In the magnetic drive device of the present invention, it is preferable that the magnet has an easy-to-magnetize axis oriented in a direction intersecting the winding axis.

In the magnetic drive device of the present invention, the magnetic flux density at a position separated from each of the first end face and the second end face by the same distance is higher in the first end face than in the second end face. preferable.

Further, in the magnetic drive device of the present invention, the magnetic material block can be configured as a bond block in which a powdery magnetic material is fixed with a resin material.

Furthermore, the present invention includes a coil, and a freely movable portion moves in the winding space of the coil, in the manufacturing method of a magnetic drive having a magnet provided on the movable portion,
Using a magnetic block that is solid and has a first and second end faces that are parallel to each other and a coil facing side surface that extends in the direction perpendicular to each end face.
The side yoke is intermittently or continuously opposed to the coil facing side surface, the end surface yoke is opposed to the first end surface, and the side yoke faces the magnetic block from the coil facing side surface to the central portion. A magnetic field for magnetizing is applied to magnetize almost the entire surface of the coil facing side surface to the same polarity, and the first end face and the second end face are magnetized to a magnetic pole different from that of the coil facing side surface. Form a magnet,
The first end face and the second end face of the magnet are oriented in the moving direction, so that the direction of the winding shaft of the coil facing the outside of the side surface facing the coil coincides with the moving direction. only write it sets the magnet on the movable part,
The movable portion is moved by an electromagnetic force generated by a magnetic flux formed between the first end face and the second end face and the side surface facing the coil and crossing the coil, and a current flowing through the coil. It is a feature.

In the method for manufacturing a magnetic drive device of the present invention, a plurality of the side yokes are provided, and exciting coils wound around the side yokes are provided, and the end face yokes are provided on all the side yokes. It can be realized by continuous things.

The magnetic drive device of the present invention magnetizes a magnetic material block having magnetic anisotropy with its easy-to-magnetize axis directed in one direction, so that a solid magnet has a coil facing side surface, a first end surface, and a first end surface. A magnet is formed by magnetizing a magnetic pole opposite to the second end face, and this magnet is incorporated in a movable portion.

Although this magnet is small, the coercive force can be increased, and the magnetic flux density applied to the coil from the side surface facing the coil can be increased. Therefore, the magnetic drive device can also be small and have a large output.

A perspective view showing the appearance of the magnetic drive device according to the embodiment of the present invention. Sectional drawing of the magnetic drive device shown in FIG. A perspective view illustrating a state in which the coil and the magnet of the magnetic drive device shown in FIG. 1 face each other. A perspective view of a magnetizing device that magnetizes a magnet used in the magnetic driving device shown in FIG. Explanatory drawing which shows the magnetizing process of the magnet used for the magnetic driving device shown in FIG. (A) is an operation explanatory view of the magnetizing device shown in FIGS. 4 and 5, and (b) is a conceptual diagram of an exciting pulse voltage waveform for magnetizing.

1 and 2 show the magnetic drive device A according to the embodiment of the present invention. The magnetic drive device A operates as a linear actuator or a vibration device.

In the magnetic drive device A, the coil 3 is wound around a fixed portion 2 that serves as a coil bobbin. The fixed portion 2 is provided with a space 4 extending along the winding shaft O of the coil 3, and a movable portion 5 is provided in the space 4. That is, the movable portion 5 is provided in the winding space of the coil 3. As shown in FIG. 2, the movable portion 5 has a magnet 1, an upper shaft 6 fixed to the upper side of the magnet 1 in the drawing, and a lower shaft 7 fixed to the lower side of the magnet 1 in the drawing. A support spring 8 which is a leaf spring is fixed to the fixing portion 2, and the lower shaft 7 is supported by the support spring 8. The fixing portion 2, the upper shaft 6 and the lower shaft 7 are made of a non-magnetic material.

The magnet 1 is a solid single member having no holes and not having a bonded structure, and has a cylindrical shape or a disk shape. The magnet 1 has a coil facing side surface 11 which is a cylindrical surface facing the coil 3 from the inside, and a first end surface 13 and a second end surface 14 facing each other in parallel in the direction along the winding axis O of the coil 3. ing. The lower flange portion 6a of the upper shaft 6 is fixed to the first end surface 13, and the upper flange portion 7a of the lower shaft 7 is fixed to the second end surface 14.

As shown in FIGS. 2 and 3, in the magnet 1, the first end face 13 and the second end face 14 are magnetized to the same magnetic pole, and the coil facing side surface 11 has the first end face 13 and the second end face 13 and the second end face 14. The end face 14 is magnetized on a magnetic pole having opposite polarity. In the embodiment, the first end face 13 and the second end face 14 have N poles, and the coil facing side surface 11 has S poles. The polarity of each surface may be opposite to that of the embodiment. Further, two magnets 1 may be provided in one movable portion 5.

As shown in FIG. 3, in the magnetic drive device A, in the magnet 1, the magnetic flux B from the first end surface 13 toward the coil facing side surface 11 crosses the coil 3, and from the second end surface 14 to the coil facing side surface 11. The magnetic flux B heading also crosses the coil 3. The electromagnetic force F due to the magnetic flux B and the current Ca flowing through the coil 3 acts on the movable portion 5, and the movable portion 5 moves along the winding shaft O of the coil 3.

Since this magnetic drive device A uses a solid magnet 1 that does not have holes and is not joined, the volume of this magnet 1 can be increased even if the size is relatively small, and the coercive force can be increased. Can be raised. Therefore, the magnetic flux density across the coil 3 can be increased, and a large electromagnetic force F can be exerted.

4 to 6 show a step of magnetizing the magnet 1. The magnet 1 used in the magnetic drive device A is manufactured by magnetizing a cylindrical or disc-shaped magnetic block 10. The magnetic block 10 is a bond block, and the magnetized magnet 1 is a bond magnet.

The bond block is made by solidifying magnetic powder, which is a powdery magnetic material, with a binder resin. The magnetic powder is Sm-Fe-N type (samarium-iron-nitrogen type) or Nd-Fe-B type (neodymium-iron-boron type). Alternatively, a plurality of types of magnetic powder may be mixed and used. The binder resin is PA (polyamide resin). The magnetic block 10 can be called a rare earth block, and the completed magnet 1 is a rare earth magnet.

The magnetic block 10 has magnetic anisotropy, and the easily magnetized axis EA is in a direction orthogonal to the central axis of the cylindrical or disc-shaped magnetic block 10 (corresponding to the winding axis O of the coil 3). It is aimed. Since the magnetic block 10 has a columnar or disc shape, the easy-to-magnetize axis EA is directed in the radial direction and radially. The magnetic block 10 can be molded by injecting a mixture of magnetic powder and a binder resin into the inside of the mold. At this time, the magnetic block 10 is molded in a magnetic field orthogonal to the central axis to easily magnetize the axis EA. A magnetic anisotropy magnetic block 10 is formed in which is directed in the X direction. Alternatively, the magnetic block 10 can be molded by so-called compaction molding in which magnetic powder mixed with a binder resin is pressed with a mold. Also in this case, the easy magnetization axis EA can be set by compression molding the magnetic powder in the Z direction in a magnetic field orthogonal to the central axis.

Since the magnetic block 10 is a bond block and can be formed by injection molding using a mold or the like, there is a degree of freedom in the shape, and the thickness and diameter in the Z direction can be freely set.

The magnetizing device 20 is shown in FIGS. 4 to 6. The magnetizing device 20 has a magnetizing yoke 21. The magnetizing yoke 21 is made of a soft magnetic material such as a Ni—Fe alloy (nickel-iron alloy). The magnetizing yoke 21 is integrally formed with a plurality of side surface yokes 21a facing the coil facing side surface 11 of the magnetic block 10 and an end surface yoke 21b facing the first end surface 13. As shown in FIG. 4, the plurality of side yokes 21a are arranged at a constant angular pitch along the circumferential direction of the coil facing side surface 11 of the magnetic block 10. The end face yoke 21b is continuous with all the side surface yokes 21a, and the end face yoke 21b and all the side surface yokes 21a have the same magnetic path distance.

A first exciting coil 22a is wound around each side yoke 21a, and a second exciting coil 22b is wound around the end surface yoke 21b. As shown in FIG. 6A, the exciting coils 22a and 22b are connected in series, and the drive circuit 25 is connected to the exciting coils 22a and 22b.

In FIG. 6A, only two side yokes 21a are shown, but when four side yokes 21a are provided as shown in FIG. 4, four first exciting coils 22a are provided. A second exciting coil 22b is connected in series between a first exciting coil 22a located at one end of the series and a first exciting coil 22a located at the other end. It becomes a structure that intervenes.

The drive circuit 25 has a DC power supply 26 and a switch 27. The switch 27 is composed of an active element such as a transistor, and is switched on and off at a predetermined cycle. When the switch 27 is ON, the drive voltage of the waveform shown in FIG. 6B is generated by the time constant determined by the capacitor C, the choke coil L, and the fixed resistor R, and this is applied to the excitation coils 22a and 22b. .. The full width at half maximum T of the drive voltage shown in FIG. 6B is about 130 μs.

At the moment when the switch 27 of the drive circuit 25 is switched from OFF to ON, an exciting current that suddenly rises flows through the exciting coils 22a and 22b based on the voltage waveform of FIG. 6B. Due to this exciting current, the exciting magnetic flux Φ1 circulates inside the magnetizing yoke 21 between the end face yoke 21b and the respective side surface yokes 21a. By repeatedly applying the exciting magnetic flux Φ1, as shown in FIGS. 3 and 4, the coil facing side surface 11 of the magnetic block 10 is magnetized to the S pole, and the first end surface 13 and the second end surface 14 are N. The magnet 1 is completed by being magnetized to the pole.

As shown in FIG. 5, the magnetic material block 10 has magnetic anisotropy, and the easily magnetized axis EA is set in a direction orthogonal to the central axis in the entire block, and the direction (Z) of the central axis as the entire block. Direction) is the axial direction in which magnetization is difficult. As shown in FIGS. 5 and 6, when an exciting magnetic field is applied from the outside, the inside of the magnetic block 10 is likely to be magnetized in the direction of the easy-to-magnetize axis EA, but it is extremely difficult to magnetize in the direction of the difficult-to-magnetize axis. Have difficulty.

As shown in FIG. 5, when an exciting magnetic field directed toward the center is simultaneously applied to the cylindrical or disc-shaped magnetic block 10 from the plurality of side yokes 21a, the coil facing side surfaces are inside the magnetic block 10. It is magnetized from 11 toward the center. At the center of the magnetic block 10, the magnetic field from the coil facing side surface 11 toward the center is confined to form a cusped magnetic field. At this time, since the end face yoke 21b is also excited at the same time, the cusp magnetic field at the center of the magnetic block 10 is oriented in the direction of the end face yoke 21b.

In the magnet 1 magnetized in this way, the coil facing side surface 11 is magnetized to the S pole on almost the entire surface direction, and the first end face 13 and the second end face 14 are magnetized to the N pole. .. However, since the cusp magnetic field at the center of the magnetic block 10 is attracted to the end face yoke 21b, the magnetic force of the north pole on the first end face 13 becomes the magnetic force of the north pole on the second end face 14 after magnetization. It becomes stronger than magnetic force. That is, the magnetic flux density at a position separated from each of the first end face 13 and the second end face 14 by the same distance is such that the first end face 13 is higher than the second end face 14.

Further, since the magnet 1 has the easy-to-magnetize axis EA oriented radially perpendicular to the central axis, the magnetic flux density passing through the coil facing side surface 11 can be increased, and a small magnet 1 is used to drive a large magnet. You can gain power.

In the method for manufacturing the magnetic drive device A of the present invention, the magnet 1 magnetized in the above step is incorporated into the movable portion 5, and the magnet 1 is incorporated into the fixed portion 2 around which the coil 3 is wound to complete the assembly.

In the embodiment shown in FIG. 4 and the like, the plurality of side yokes 21a are arranged at a constant angular pitch along the coil facing side surface 11 of the magnetic block 10, but the side yoke is the coil facing side surface. It may be a ring-shaped yoke provided continuously along the eleven.

1 Magnet 2 Fixed part 3 Coil 5 Moving part 10 Magnetic material block 11 Coil facing side surface 13 First end surface 14 Second end surface 20 Magnetizing device 21 Magnetizing yoke 21a Side yoke 21b End surface yoke 25 Drive circuit A Magnetic drive device EA Easy magnetization axis

Claims (7)

In a magnetic drive having a coil, a freely movable portion moves in the winding space of the coil, and a magnet provided on the movable portion,
Said magnet is formed of a solid magnetic block, possess a first end face and second end surfaces parallel to each other, a coil opposing sides extending the perpendicular direction of the end faces, of the coil opposite sides Almost the entire surface and the first end face and the second end face are magnetized in opposite polarities .
In the movable portion, the first end surface and the second end surface of the magnet are directed in the moving direction, and the direction of the winding shaft of the coil facing the outside of the coil facing side surface and the moving direction are Match and
The movable portion is moved by an electromagnetic force generated by a magnetic flux formed between the first end face and the second end face and the side surface facing the coil and crossing the coil, and a current flowing through the coil. A characteristic magnetic drive device. The magnetic driving device according to claim 1, wherein the length dimension of the coil in the moving direction is larger than the distance between the first end face and the second end face. The magnetic driving device according to claim 1 or 2 , wherein the magnet is directed in a direction in which an easily magnetized shaft intersects the winding shaft. The magnetic flux density at a position separated from each of the first end face and the second end face by the same distance is according to any one of claims 1 to 3, wherein the first end face is higher than the second end face. Magnetic drive device. The magnetic drive device according to any one of claims 1 to 4, wherein the magnetic block is a bond block in which a powdery magnetic material is fixed with a resin material. Coil and a freely movable portion moves in the winding space of the coil, in the manufacturing method of a magnetic drive having a magnet provided on the movable portion,
Using a magnetic block that is solid and has a first and second end faces that are parallel to each other and a coil facing side surface that extends in the direction perpendicular to each end face.
The side yoke is intermittently or continuously opposed to the coil facing side surface, the end surface yoke is opposed to the first end surface, and the side yoke faces the magnetic block from the coil facing side surface to the central portion. A magnetic field for magnetizing is applied to magnetize almost the entire surface of the coil facing side surface to the same polarity, and the first end face and the second end face are magnetized to a magnetic pole different from that of the coil facing side surface. Form a magnet,
The first end face and the second end face of the magnet are oriented in the moving direction, so that the direction of the winding shaft of the coil facing the outside of the side surface facing the coil coincides with the moving direction. only write it sets the magnet on the movable part,
The movable portion is moved by an electromagnetic force generated by a magnetic flux formed between the first end face and the second end face and the side surface facing the coil and crossing the coil, and a current flowing through the coil. A characteristic method for manufacturing a magnetic drive device. The magnetic drive according to claim 6, wherein a plurality of the side yokes are provided, and exciting coils wound around the side yokes are provided, and the end face yokes are continuous with all the side yokes. Manufacturing method of the device.

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