JP2009130988A - Magnetostrictive multi-shaft drive actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotating and revolving magnetostrictive multi-shaft drive actuator which can be reduced in size and simplified. <P>SOLUTION: The magnetostrictive multi-shaft drive actuator comprises a spherical-shaped rotation member 8 made of a magnetic body and capable of rotating and revolving, at least two magnetostrictive members 2, a coil 4 wound around the magnetostrictive members, and a permanent magnet 6 for holding the rotation member and applying a bias magnetic field onto the magnetostrictive members. The magnetostrictive members are deformed by an AC magnetic field and a bias magnetic field, and the magnetostrictive members are so arranged as to be in parallel with each other in the deformation direction; one end 2a of the magnetostrictive member which is brought into contact with each rotating member, while the other end 2b is fixed so as to transmit the deformation of the magnetostrictive member to the rotation member; and the permanent magnets are so arranged as to energize the rotating member toward one end of the magnetostrictive member by the magnetic force. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an actuator using a magnetostrictive material, and more particularly to an actuator using an iron-based high magnetostrictive material such as an iron gallium-based magnetostrictive material.

  Conventionally, as various actuators and motors that can be driven in multiple axes, piezoelectric elements have been used in, for example, ultrasonic actuators and ultrasonic motors. However, piezoelectric elements have high operating voltage, low mechanical strength, and are brittle. There was a problem.

  In response to such problems, actuators and motors using magnetostrictive materials that are displaced by a magnetic field have been developed using giant magnetostrictive materials that have a large displacement and excellent responsiveness. (See Patent Document 1)

  However, the giant magnetostrictive material is a rare earth alloy mainly composed of terbium element, dysprosium element and iron group element, and its displacement amount is more than 100 times that of the ordinary magnetostrictive magnetostrictive material. On the other hand, it is fragile and difficult to handle, and its workability is poor, so ordinary cutting is not suitable. In addition, since it contains rare earth elements, there is a problem that it is very expensive.

  In order to use the giant magnetostrictive material as an actuator that performs high-precision operation, a mechanism for applying a compression preload by the method described in, for example, Japanese Patent No. 2793097 (Patent Document 2) is essential.

  This increases the magnetostriction sensitivity of the giant magnetostrictive material by compressive preload, and the giant magnetostrictive material is strong against external compression force but very weak against tensile force. This is to prevent the material from being damaged by force.

  In recent years, Fe-Ga alloys have been developed as materials having a large magnetostriction amount. Although the amount of displacement does not reach that of a giant magnetostrictive material containing a rare earth element, it has workability and high rigidity and is inexpensive compared to a giant magnetostrictive material made of a rare earth alloy. Moreover, it has a relatively high magnetostriction sensitivity without giving a compression preload.

Japanese Patent No.2652644 Japanese Patent No. 2793097

  As described above, when a giant magnetostrictive material made of a rare earth alloy is used for a mechanism of an actuator that performs a highly accurate operation, a preload mechanism that restrains and pressurizes both ends of the magnetostrictive material is indispensable in order to increase magnetostriction sensitivity. Therefore, a mechanism for pressing the rotating part of the actuator is particularly necessary, and there is a problem that it is difficult to reduce the size and simplify the actuator.

  The present invention has been made in order to solve the above-described problems. The mechanism of the rotating part is simplified without applying preload, and the impedance of the coil can be kept low by downsizing and simplification, and low voltage driving is possible. An object of the present invention is to provide a magnetostrictive multi-axis drive actuator capable of rotating and rotating.

  In order to achieve the above object, the magnetostrictive multi-axis drive actuator of the present invention uses a high-magnetostrictive material having a large magnetostriction amount, such as an Fe-Ga alloy, and is made of a magnetic material and is a spherical or rotationally rotatable. The structure includes a member, at least two magnetostrictive members, a coil wound around the magnetostrictive member, and a permanent magnet that holds the rotating member and applies a bias magnetic field to the magnetostrictive member.

  The magnetostrictive member is displaced by the alternating magnetic field generated from the coil and the bias magnetic field, and the magnetostrictive members are disposed so that the displacement directions thereof are parallel to each other, and the displacement of the magnetostrictive member is transmitted to the rotating member. One end of the magnetostrictive member is in contact with the rotating member and the other end is fixed, and the permanent magnet is arranged to urge the rotating member toward one end of the magnetostrictive member by a magnetic force.

  With such a configuration, it is not necessary to hold the rotating member by a special holding mechanism such as a press plate, and the rotating mechanism becomes simple. Further, since a holding mechanism such as a holding plate is not required, the rotation or rotation of the rotating member is not interfered by these holding mechanisms, and can be freely rotated or rotated around the center of the sphere of the rotating member. The rotation angle or the rotation angle can be increased, and the rotation is also smooth.

  The rotating member may include a rod for transmitting the rotation or rotation to the outside. With such a configuration, the rotation or rotation of the rotating member can be taken out effectively.

The permanent magnet may be disposed at a position surrounded by each magnetostrictive member in the vicinity of one end of the magnetostrictive member.
With such a configuration, the outer diameter of the magnetostrictive multi-axis drive actuator can be made approximately the same as the arrangement interval of the magnetostrictive members, and the size can be reduced.

  The magnetostrictive member may be a bimorph formed by laminating a negative magnetostrictive material extending in the longitudinal direction from the one end toward the other end and a positive magnetostrictive material extending in the longitudinal direction. Bimorphs are deformed to bend as the positive magnetostrictive material expands and the negative magnetostrictive material contracts. When these other ends are fixed and cantilevered, the vicinity of the one end is displaced in the thickness direction.

  When a ring-shaped magnetic member is joined to the magnetostrictive member and the rotating member is brought into contact with the ring-shaped magnetostrictive member, the magnetostrictive member and the rotating member are evenly contacted, and displacement of the magnetostrictive member is efficiently performed. It can be transmitted well to the rotating member.

  According to the present invention, it is possible to provide a magnetostrictive multi-axis drive actuator that can perform rotation and rotation operations with high accuracy and that can be reduced in size and simplified.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a configuration of a magnetostrictive multi-axis drive actuator according to the first embodiment of the present invention. In this figure, a magnetostrictive multi-axis drive actuator 20 includes a spherical rotating member 8 made of a magnetic material, four rod-like magnetostrictive members 2 of the same size, a coil 4 wound around the magnetostrictive member 2, and a cylindrical shape. A permanent magnet 6 and a support base 10 to which a lower end (other end) 2b of the magnetostrictive member 2 is fixed are provided.

  Each magnetostrictive member 2 is arranged so that its longitudinal direction (vertical direction in FIG. 1) is parallel and the upper end (one end) 2a is substantially flush. Further, in the plane perpendicular to the longitudinal direction of each magnetostrictive member 2, each magnetostrictive member 2 is arranged at an angular difference of 90 degrees on the circumference concentric with the rotating member 8.

  The permanent magnet 6 is disposed along the longitudinal direction of the magnetostrictive member 2 and at the center of the circumference so that the tip of the permanent magnet 6 is slightly lower than the upper end 2a of each magnetostrictive member 2. The member 2 is surrounded. The lower end of the permanent magnet 6 is fixed to the support base 10.

  The rotating member 8 is disposed on each magnetostrictive member 2 while being in contact with the upper end 2a of each magnetostrictive member 2, and is attracted to the magnetic force of the permanent magnet 6 and biased toward the upper end 2a side of each magnetostrictive member 2. For this reason, it is not necessary to hold the rotating member 8 by a special holding mechanism, for example, a pressing plate, and the rotating mechanism becomes simple.

  Further, since a holding mechanism such as a holding plate is unnecessary, the rotation or rotation of the rotating member 8 is not hindered by these holding mechanisms, and the rotating member 8 can freely rotate or rotate around the center of the sphere. It is. For this reason, the rotation angle or the rotation angle can be increased, and the rotation is also smooth.

The permanent magnet 6 and the rotating member 8 may be in contact with each other or may not be in contact with each other.
In this embodiment, a rod 8a extending outward along the central axis of the rotating member 8 is connected to the rotating member 8, and the rotation or rotation of the rotating member 8 is transmitted to the outside.

  In the present invention, the magnetostrictive member 2 is used without applying a preload. Therefore, as the magnetostrictive member 2, it is preferable to use a high magnetostrictive material having a large magnetostriction amount without giving a preload. Examples of the high magnetostrictive material include Fe—Ga alloy, Fe—Co alloy, and Fe—Al alloy.

The magnetostrictive member 2 is displaced by the magnetic field as follows. Now, the permanent magnet 6, the bias magnetic field H _M toward the lower end 2b from the upper end 2a of the magnetostrictive member 2 is applied.

Here, among the two adjacent magnetostrictive member 2, the first magnetostrictive member 2 generates an upward magnetic field H _C by the coil 4, a downward magnetic field H _C by the coil 4 to the second magnetostrictive member 2 When generating, in the first magnetostrictive member 2 magnetic field H _M -H _C is applied to the second magnetostrictive member 2 magnetic field H _{M +} H _C is applied as a whole. Accordingly, the second magnetostrictive member 2 has a larger magnetic field, and the displacement amount is also increased.

  In this way, the second magnetostrictive member 2 extends relatively in the longitudinal direction (the direction from the upper end to the lower end), and reversely displaces so that the first magnetostrictive member 2 contracts relatively in the longitudinal direction. The displacement directions of the magnetostrictive members 2 are all longitudinal directions, and the displacement directions of the magnetostrictive members 2 are parallel to each other.

  As described above, when AC magnetic fields having opposite phases are applied to the coils 4 included in the first and second magnetostrictive members 2, the second magnetostrictive member 2 extends and the first magnetostrictive member 2 contracts. Until the second magnetostrictive member 2 is contracted and the first magnetostrictive member 2 is extended, this is repeated periodically at the frequency of the alternating magnetic field.

  The phase control of the AC magnetic field with respect to the coil 4 of each magnetostrictive member 2 by the AC magnetic field is performed as follows according to the number of arranged magnetostrictive members 2. If there are two magnetostrictive members 2, each magnetostrictive member 2 is expanded and contracted sequentially in the longitudinal direction by setting the phase difference of the current applied to the coil 4 of each magnetostrictive member 2 to 180 degrees.

  As a result, the upper ends (free ends) of the magnetostrictive members 2 are sequentially displaced, and the rotating members 8 in contact therewith are rotated left and right (in the direction in which the magnetostrictive members 2 are arranged) at a predetermined angle. The angle of the provided arm 8a can be controlled.

  If there are three magnetostrictive members 2, each magnetostrictive member 2 is expanded and contracted sequentially in the longitudinal direction (in the order of being arranged in the circumferential direction) by setting the phase difference of the current applied to the coil 4 of each magnetostrictive member 2 to 120 degrees. To do. As a result, the upper end (free end) 2a of each magnetostrictive member 2 is sequentially displaced, and the rotating member 8 in contact therewith rotates to operate as a rotary motor. Further, the higher the frequency of the alternating magnetic field, the higher the rotational speed. The rotating direction of the rotating member 8 is a circumferential direction including the upper end of each magnetostrictive member 2.

  If the number of the magnetostrictive members 2 is four, each magnetostrictive member 2 sequentially expands and contracts in the longitudinal direction by setting the phase difference of the current applied to the coil 4 of each magnetostrictive member 2 to 90 degrees. As a result, the upper end (free end) 2a of each magnetostrictive member 2 is sequentially displaced, and the rotating member 8 in contact therewith rotates to operate as a rotary motor.

  Furthermore, a pair of opposing coils are connected in series, and an upper end (free end) of the pair of magnetostrictive members is displaced by applying a current having a phase difference of 180 degrees (reverse phase) to the two pairs of coils. The rotating member 8 in contact with these rotates to the left and right (the direction in which the magnetostrictive members 2 are arranged) at a predetermined angle, and the angle of the arm 8a provided on the rotating member 8 can be controlled.

  Thus, the phase difference of the alternating magnetic field may be n / 360 degrees with respect to the number n of the magnetostrictive members 2 arranged. Further, when the magnetostrictive member 2 is simultaneously expanded and contracted in the same direction (vertical direction) without providing a phase difference, the rotating member 8 moves up and down as it is (linear motion). When the number of the magnetostrictive members 2 is three or more, they can be rotated or moved in a predetermined angle and can be rotated.

  The size of the magnetostrictive multi-axis drive actuator according to the first embodiment of the present invention is not particularly limited. For example, the rotating member 8 has a diameter of 3 to 4 mm, and each magnetostrictive member 2 has a diameter (or one side) of 1 mm. It can be about 8 mm.

  The material of the rotating member 8 can be, for example, a magnetic material among iron-based materials, stainless steel materials, and nickel-based materials.

  In addition, if it comprises so that the magnetic field of the permanent magnet 6 may come out from the support stand 10, an actuator can be adsorbed and fixed to the target object of the magnetic body put on the back surface of the support stand 10 with a magnetic force. Moreover, in order to increase the magnetic field density of the permanent magnet 6 and effectively use the magnetic force, various high permeability materials or yokes made of a magnetic material may be used.

  Next, a magnetostrictive multi-axis drive actuator according to a second embodiment of the present invention will be described with reference to FIG. In this figure, a magnetostrictive multi-axis drive actuator 21 includes a spherical rotating member 8 made of a magnetic material, four rod-like magnetostrictive members 3, a coil 4 wound around the magnetostrictive member 3, and a cylindrical permanent magnet 6. And a support base 10 to which the lower end 3b of the magnetostrictive member 3 is fixed.

  In the second embodiment, since there is no difference from the first embodiment except that the magnetostrictive member 3 is a bimorph, the same components as those in the first embodiment are denoted by the same reference numerals and described. Omitted.

  FIG. 3 is a diagram showing a configuration of the magnetostrictive member 3 which is a bimorph. The magnetostrictive member 3 is formed by laminating a negative magnetostrictive material 3x extending in the longitudinal direction from the upper end to the lower end and a positive magnetostrictive material 3y extending in the longitudinal direction, and forms a bimorph that is displaced in the vicinity of the upper end 3a that is a free end. .

  Examples of the negative magnetostrictive material 3x include Ni-based alloys. Further, examples of the positive magnetostrictive material 3y include Fe—Ga alloy, Fe—Co alloy, and Fe—Al alloy.

  These can be laminated by bonding or welding (spot welding or the like) the negative magnetostrictive material 3x and the positive magnetostrictive material 3y.

  When a magnetic field is applied to the bimorph, the negative magnetostrictive material 3x contracts, the positive magnetostrictive material 3y expands, and the upper end 3a of the bimorph curves toward the negative magnetostrictive material side (left side in FIG. 3). That is, it is displaced in the thickness direction of the bimorph.

  Further, when a bias magnetic field and an alternating magnetic field are applied, the upper end 3a of the bimorph vibrates left and right with reference to a position curved according to the bias magnetic field. Further, when the bias magnetic field is not applied and the frequency of the alternating magnetic field is selected as the resonance frequency, the upper end of the bimorph oscillates left and right with respect to the upright position.

  In the four rod-like magnetostrictive members 3 provided in the magnetostrictive multi-axis drive actuator 21 shown in FIG. 2, two pairs of bimorphs having such behavior characteristics are arranged diagonally so that the surfaces having the same characteristics face each other. Is.

  In this arrangement, for example, by applying a sawtooth waveform current shown in FIG. 4 (a) to one of the two coils to give a magnetic field, the rod 8a on the rotating member 8 is moved in a predetermined direction and angle. It can be rotated. When a current having a sawtooth waveform shown in FIG. 4B is applied to apply a magnetic field, the rod 8a rotates in the opposite direction to that in FIG.

  Further, by controlling the waveform of the current flowing through each coil of the two pairs of magnetostrictive region materials 3, it is possible to combine the rotation directions and rotate and rotate the rotating member 8 in the circumferential direction and in any direction. is there.

  In the above description, the magnetostrictive multi-axis drive actuator including four rod-shaped magnetostrictive members by bimorph has been described. However, in the second embodiment, the number of rod-shaped magnetostrictive members 3 may be any number as long as it is plural. Furthermore, the direction of the magnetostrictive member 3 may also be arranged, for example, such that the plate thickness direction of the bimorph is directed in the circumferential direction.

By controlling the waveform and timing of the current applied to each coil according to the arrangement of the magnetostrictive member 3 made of bimorph, and applying a magnetic field to the magnetostrictive member 3, various rotations and rotations are applied to the rod 8a on the rotary member 8. Can make dynamic movements.

  Next, a magnetostrictive multi-axis drive actuator according to a third embodiment of the present invention will be described with reference to FIG. In this figure, a magnetostrictive multi-axis drive actuator 22 includes a spherical rotating member 8 made of a magnetic material, a ring 9 made of a magnetic material, four rod-shaped magnetostrictive members 3, and a coil 4 wound around the magnetostrictive member 3. A cylindrical permanent magnet 6 and a support base 10 to which the lower end 2b of the magnetostrictive member 2 is fixed.

  In the third embodiment, there is no difference from the first embodiment except that a ring 9 made of a magnetic material is provided. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals and described. Is omitted.

  FIG. 5 is a view showing a configuration in which a ring 9 made of a magnetic material joined to the magnetostrictive member 3 supports the rotating member 8. According to this configuration, when the rotating member 8 contacts the ring 9 evenly, the displacement of the magnetostrictive member 3 can be efficiently transmitted to the rotating member 8.

  The present invention is not limited to the above embodiment. For example, as long as the permanent magnet is arranged to urge the rotating member toward one end of the magnetostrictive member by a magnetic force, the shape and position of the permanent magnet are not limited. That is, it is sufficient that the rotating member is attracted downward (see FIG. 1) by the permanent magnet and comes into contact with one end of the magnetostrictive member.

  For example, the permanent magnet may be formed in a ring shape surrounding each magnetostrictive member from the outside. In this case, if the permanent magnet as a whole attracts the rotating member downward, the upper end of the permanent magnet surrounds the rotating member. It may be.

  Further, if the magnetic force of the permanent magnet is increased, the permanent magnet is not necessarily arranged in the vicinity of the rotating member, and may be arranged below (see FIG. 1) spaced from one end of the magnetostrictive member. Furthermore, a predetermined yoke may be disposed in order to effectively use the magnetic force of the permanent magnet.

  Further, each magnetostrictive member may be arranged on a circumference concentric with the rotating member, and a plurality of permanent magnets may be arranged between each magnetostrictive member and on the circumference.

  The end face shape of one end of the magnetostrictive member in contact with the rotating member may be a shape provided with a step corresponding to the curvature of the rotating member as shown in FIG. Alternatively, it may be a flat surface, and in this case, a part of one end of the magnetostrictive member is in contact with the rotating member. Further, the end surface of one end of the magnetostrictive member may be a curved surface corresponding to the curvature of the rotating member, and the contact area with the rotating member may be increased.

  The coil wound around the magnetostrictive member may be attached by winding one coil around two adjacent magnetostrictive members as shown in FIG. At this time, two or more coils may be wound around one magnetostrictive member.

  The present invention can apply rotation, rotation at a predetermined angle, and, in some cases, linear motion to a rotating member. For example, it is used for a joint of a robot arm, an injector (ink discharge unit) of a printer, a positioning member, a motor, or the like. Can do. In addition, since the size is reduced and the structure is simplified, the actuator is suitable for a place where space saving is required (for example, for changing the angle of an imaging mirror of a medical catheter).

It is a perspective view which shows the structure of the magnetostrictive multi-axis drive actuator which concerns on the 1st Embodiment of this invention. It is a perspective view which shows the structure of the magnetostrictive multi-axis drive actuator which concerns on the 2nd Embodiment of this invention. It is a figure which shows the structure of the magnetostrictive member 3 which is a bimorph. It is an input waveform figure in the 2nd Embodiment of this invention. It is a perspective view which shows the structure of the magnetostrictive multi-axis drive actuator which concerns on the 3rd Embodiment of this invention. It is a perspective view which shows the structure of the magnetostrictive multi-axis drive actuator which concerns on other embodiment of this invention.

Explanation of symbols

2, 3 Magnetostrictive member 2a, 3a One end of magnetostrictive member 2b, 3b The other end of magnetostrictive member 3x Negative magnetostrictive material 3y Positive magnetostrictive material 4 Coil 6 Permanent magnet 8 Rotating member 8a Rod 9 Ring 10 Heating means 20, 21, 22 Magnetostrictive type Multi-axis actuator

Claims (5)

A spherical rotating member made of a rotatable or rotatable magnetic body, at least two magnetostrictive members, a coil wound around the magnetostrictive member, holding the rotating member, and applying a bias magnetic field to the magnetostrictive member With a permanent magnet,
With respect to the magnetostrictive member, when an alternating magnetic field generated from the coil and the bias magnetic field from the permanent magnet are applied, the displacement directions of the magnetostrictive member are arranged in parallel to each other,
In order to transmit the displacement of the magnetostrictive member to the rotating member, one end of the magnetostrictive member is in contact with the rotating member, and the other end is fixed,
The permanent magnet is a magnetostrictive multi-axis drive actuator arranged to urge the rotating member toward one end of the magnetostrictive member by a magnetic force.   The magnetostrictive multi-axis drive actuator according to claim 1, wherein the rotating member includes a rod for transmitting the rotation or rotation to the outside.   The magnetostrictive multi-axis drive actuator according to claim 1, wherein the permanent magnet is disposed at a position surrounded by each magnetostrictive member in the vicinity of one end of the magnetostrictive member.   The magnetostrictive member is formed by laminating a negative magnetostrictive material extending in the longitudinal direction from the one end toward the other end and a positive magnetostrictive material extending in the longitudinal direction, and is displaced in the plate thickness direction of the magnetostrictive member in the vicinity of the one end. The magnetostrictive multi-axis drive actuator according to claim 1, wherein the magnetostrictive multi-axis drive actuator is a bimorph. The magnetostrictive multi-axis drive actuator according to any one of claims 1 to 4, wherein a ring-shaped magnetic member is joined to the magnetostrictive member so that the magnetostrictive member and the rotating member are in uniform contact with each other.

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