JPH05145139A - Magnetostriction actuator - Google Patents

Abstract

PURPOSE:To provide a compact magnetostrictive actuator with a simplified structure by obtaining a large amount of operation. CONSTITUTION:A magnetostrictive material 14 and a coil winding 12 are accommodated in a housing 11. A fixing part 15 which is engaged to one edge of the magnetostrictive material 14 is provided at one side of the housing 11. A movable member 16 which is engaged to the other edge of the magnetostrictive material 14 is provided at the other side of the housing 11. A pressurized chamber 18 which houses a fluid 26 which is pressurized by a displacement of the magnetostrictive material is provided between the movable member 16 and the housing 11. A transfer knob 23 is engaged to a hole part 20a which is provided at the member constituting the pressurized chamber 18 through a seal material 22 so that it can slide freely. The transfer knob 23 is provided with a pressure-reception sectional area with a smaller fluid than a sectional area of the pressurized chamber 18. A fluid within the pressurized chamber 18 is compressed by a displacement of the magnetostrictive material 14, thus enabling the transfer knob 23 to be moved along the hole part 20a. A permanent magnet which applies a constant magnetic field to the magnetostrictive material 14 may be provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetostrictive actuator using a magnetostrictive material which is displaced when a magnetic field is applied.

[0002]

2. Description of the Related Art A conventional actuator using a magnetostrictive material is constructed as shown in FIG. That is, the winding 2 is housed in the housing 1, the positive magnetostrictive material 4 is housed in the bobbin 3 around which the winding 2 is wound so as to be expandable and contractible in the axial direction of the bobbin 3, and one end of the magnetostrictive material 4 is yoked. Housing 1 through 5
It is received by the end plate 1a, and one end of the transmission knob 6 is brought into contact with the other end. The transmission knob 6 has a tip projecting from the other end plate 1b of the housing 1, and a flange 8 and an end plate 1b provided on the transmission knob 6 are provided.
The return spring 7 is interposed between and.

This actuator extends the magnetostrictive material 4 by energizing the winding 2 and applying a magnetic field to the magnetostrictive material 4, thereby pushing out the transmission knob 6 and moving an actuated body (not shown). Is.

[0004]

Such a magnetostrictive actuator has a quick response and an output as compared with a conventional electromagnetic actuator of a type in which a magnetic material is attracted by a magnetic force generated by energizing a winding. Although it has the advantage that it is also large, the maximum amount of deformation of the magnetostrictive material is currently only about 0.15%. A mechanism has to be provided and a long magnetostrictive material has to be used, and there has been a problem that size increase is inevitable.

In view of the above problems, it is an object of the present invention to provide a small-sized magnetostrictive actuator which has a large amount of movement and has a simplified structure.

[0006]

In order to achieve the above object, the present invention provides a magnetostrictive material, a winding for generating a magnetic field applied to the magnetostrictive material, a housing containing the magnetostrictive material and the winding, and A fixed portion on one side of the housing engaged with one end of the magnetostrictive material, a movable member on the other side of the housing engaged with the other end of the magnetostrictive material, and between the movable member and the housing. A pressurizing chamber that is provided and contains a fluid that is pressurized by the displacement of the magnetostrictive material, and a member that constitutes the pressurizing chamber that has a pressure receiving cross-sectional area of the fluid that is smaller than the cross-sectional area of the pressurizing chamber. A transmission knob that is slidably fitted in a provided hole through a sealing material, and that moves along the hole when the fluid in the pressure chamber is compressed by the displacement of the magnetostrictive material; A magnetostrictive actuator is constructed with an elastic material that returns the transmission knob. Characterized in that it was.

[0007]

Since the present invention has the above structure, when the winding is energized, the magnetic material is displaced against the return spring, whereby the pressurizing chamber is compressed via the movable member, and as a result, A transmission knob having a pressure receiving area smaller than that of the pressure chamber is displaced along the hole. The displacement amount of the transmission knob is amplified by multiplying the displacement amount of the movable member by the ratio of the sectional area of the pressurizing chamber: the pressure receiving area of the transmission knob.

[0008]

1 is a longitudinal sectional view showing an embodiment of a pulling actuator according to the present invention, and FIG. 2 is a sectional view taken along the line EE. Reference numeral 11 is a cylindrical housing, 12 is a cylindrical winding wound around the bobbin 13, and 14 is a cylindrical positive magnetostrictive material accommodated in the center hole of the bobbin 13 so as to be expandable and contractible in the axial direction. The lower end of the magnetostrictive material 14 (the lower end in the drawing, which will be described below in the same vertical relationship) is in contact with the end plate (fixed receiving portion) 15 of the housing 11.

The upper end of the magnetostrictive material 14 is in contact with a lower surface projection 16a of a cylinder 16 which is a bottomed tubular movable member fitted in the housing 11 so as to be vertically movable.
A lid 17 is slidably fitted on the cylinder 16, and a seal rubber 21 is interposed between the lid 17 and the cylinder 16 to remove the lid 1.
A pressurizing chamber 18 is formed between the cylinder 7 and the cylinder 7.
The lid 17 has a screw groove 11 a provided on the inner surface of the housing 11.
The pressing plate 19 screwed into the roller presses against the elasticity of the seal rubber 21.

The lid 17 has a tube 20 at its center, and a transmission knob 23 is fitted in a hole 20a of the tube 20 via a seal ring 22. The transmission knob 23 projects outward from a center hole 24a of an end plate 24 screwed into the upper end of the housing 11, and a coil spring 25 is provided as an elastic material between the flange 23a of the transmission knob 23 and the end plate 24. Is intervening.
A fluid 26, preferably a liquid, is enclosed in the pressurizing chamber 18.

It is preferable that the housing 11, the end plate 15, and the cylinder 16 are made of a magnetic material to form a closed magnetic path for the magnetic field generated in the winding 12.

In this actuator, when the winding 12 is energized, the magnetostrictive material 14 extends, but the lower end of the magnetostrictive material 14 is received by the end plate 15 and is prevented from moving up and down relative to the housing 11. However, since the cylinder 16 above the magnetostrictive material 14 can be lifted relative to the housing 11, the cylinder 16 is pushed up. As a result, the fluid 26 in the pressurizing chamber 18 is compressed and the transmission knob 23
Are pushed up by the pressurized fluid. When the power supply to the winding wire 12 is stopped, the magnetostrictive material 14 contracts and the coil spring 2
The transmission knob 23 is pushed down by 5 to return to the original position, and the cylinder 16 also descends and returns to the original position.

Here, the cross-sectional area of the lid 17 is S, and the transmission knob 2
3 is s, the displacement amount of the magnetostrictive material 14 is a, and the displacement amount of the transmission knob 23 is A, the relation A = a × (S / s) is established, and As the operation amount of the knob 23, a large displacement amount obtained by amplifying the displacement amount of the magnetostrictive material 14 by S / s is obtained.

In FIG. 3, the magnetostrictive material 14 and the permanent magnet 27 are laminated, and the permanent magnet 27 causes the constant magnetic field ΔH to be a bias magnetic field in the magnetostrictive material 14 (this magnetic field strength is the maximum expansion of the magnetostrictive material 14). The strength is equivalent to about half of the quantity)
In addition, the magnetostrictive material 14 is expanded / contracted by applying a magnetic field ΔH or −ΔH applied to the winding 12 to generate a magnetic field for canceling it. The effect that the current can be made small and miniaturization can be achieved is obtained.

FIG. 4A is a longitudinal sectional view showing another embodiment of the present invention, and FIG. 4B is a sectional view taken along the line F--F of FIG. Magnetostrictive material 1
4 is formed in a cylindrical shape, the transmission knob 23 is inserted in the magnetostrictive material 14, the lid 17 is a movable member, the end plate 24 is a fixed portion for receiving the magnetostrictive material 14, and the end plate 24 and the collar 23a of the transmission knob 23 are provided. The coil spring 25 is interposed between the two.

In the present embodiment, by energizing the winding 12, the lid 17 is pushed, the fluid in the pressurizing chamber 18 is pressurized, and the transmission knob 23 is pushed up, as described in the previous embodiment. , The amount of amplification is determined by the ratio of the pressure receiving area of the lid 17 and the pressure receiving area of the transmission knob 23. In this embodiment as well, a permanent magnet that applies a bias magnetic field may be provided to the magnetostrictive material 14.

In the present invention, as the shape and structure of the magnetostrictive material, various ones other than those described above can be adopted. For example, a plurality of magnetostrictive materials each having a sectional shape obtained by dividing an arc may be combined. A book-shaped magnetostrictive material or rod-shaped magnetostrictive material may be combined. It is also possible to use a magnetostrictive material having a negative characteristic that contracts when a magnetic field is applied. In addition, various modifications and additions can be made without departing from the scope of the present invention, such as configuring the housing 11 by combining a plurality of rods and end plates.

[0018]

According to the first aspect of the present invention, the operation is performed due to the difference in cross-sectional area between the pressurizing chamber compressed by the magnetostrictive material and the transmission knob fitted in the hole provided in the member forming the pressurizing chamber. Since it is configured to amplify the amount, a large operation amount can be obtained, and a small-sized magnetostrictive actuator having a simplified structure can be provided as compared with a device using an operation amount amplification mechanism such as a lever.

According to the second aspect, since the magnetic field generated in the winding can be reduced, the winding can be downsized and the overall shape can be downsized.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of an actuator according to the present invention.

FIG. 2 is a sectional view taken along line EE of FIG.

FIG. 3 is a vertical cross-sectional view showing another configuration example of the magnetostrictive material of the present invention.

FIG. 4A is a vertical sectional view showing another embodiment of the actuator according to the present invention, and FIG. 4B is a sectional view taken along line FF.

FIG. 5 is a vertical sectional view showing a conventional strain actuator.

[Explanation of symbols]

 11 Housing 12 Winding 13 Bobbin 14 Positive Magnetostrictive Material 15, 24 End Plate 16 Cylinder 17 Lid 18 Pressurizing Chamber 19 Holding Plate 20a Hole 21 Seal Rubber 22 Seal Ring 23 Transmission Knob 25 Coil Spring 26 Fluid 27 Permanent Magnet

Claims (2)

[Claims] 1. A magnetostrictive material, a winding for generating a magnetic field applied to the magnetostrictive material, a housing accommodating the magnetostrictive material and the winding, and one end of the housing engaged with one end of the magnetostrictive material. A fixed portion, a movable member on the other side of the housing that is engaged with the other end of the magnetostrictive material, and a fluid that is provided between the movable member and the housing and is pressurized by the displacement of the magnetostrictive material. The pressurizing chamber accommodated therein has a pressure-receiving cross-sectional area of the fluid that is smaller than the cross-sectional area of the pressurizing chamber, and is slidably fitted into a hole provided in a member forming the pressurizing chamber via a sealing material. A transmission knob that moves along the hole when the fluid in the pressurizing chamber is compressed by the displacement of the magnetostrictive material, and an elastic material that restores the transmission knob. Magnetostrictive actuator. 2. The magnetostrictive actuator according to claim 1, further comprising a permanent magnet that applies a constant magnetic field to the magnetostrictive material.