JPH0715053A - Magnetostriction actuator - Google Patents

Abstract

PURPOSE:To provide a magnetostriction actuator wherein the output loss of an actuator is small and the size is not enlarged by a preload generating means. CONSTITUTION:The title magnetostriction actuator consists of the following; rod type magnetic material 11 having magnetostriction as a displacement generating means, a solenoid coil 12 as a magnetic field generating means which is arranged around the magnetic material 11, a driving rod 13 as a movable member for transferring the displacement output of a magnetostriction actuator linked with one end of the magnetic material 11, a fixing base connected with the other end of the magnetic material, and a cylindrical case 15 which is fixed to the fixing base 14 so as to surround the solenoid coil 12. The driving rod 13 is connected with the cylindrical case 15 by using a linkage member 17 with flexibility.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetostrictive actuator provided with a magnetic body that produces magnetostriction by applying a magnetic field.

[0002]

2. Description of the Related Art As an actuator for generating vibration and displacement, there has been known a piezoelectric actuator in which a piezoelectric material is used as a displacement generating element and a vibration and displacement are generated by applying a control voltage to the displacement generating element. Has been. Further, an electromagnetic actuator that uses the principle of a speaker and a magnetostrictive actuator that uses the magnetostriction phenomenon of a magnetic material are generally known.

As for the actuator for generating vibration and displacement, it is desired to develop an actuator that is small in size and has a high output, that is, that can generate a larger displacement and force.
Conventionally, Ni-based alloys, Fe-Al-based alloys, and ferrite-based alloys have been mainly used as the magnetic material forming the magnetostrictive actuator. Further, recently, development of a rare earth metal-transition metal-based giant magnetostrictive alloy capable of generating a displacement larger than that of the magnetic material by one digit or more has been reported.

The magnetostrictive actuator is generally provided with a means for applying a control electric field to the magnetic body. As the magnetic field applying means, a magnetic circuit using an electromagnet or the like that can easily control the magnetic field by supplying a control current is mainly used.

FIG. 11 is a schematic sectional view of a vibrator usable as a small pump or a panel speaker as an example of a conventional magnetostrictive actuator. This vibrator includes a rod-shaped magnetic body 1 made of a giant magnetostrictive alloy, a solenoid coil 2 arranged around the magnetic body 1 for applying a control magnetic field to the magnetic body 1, and both ends of the magnetic body 1. The drive rod 3 and the fixed platen 4 are connected to each other, and the cylindrical case 5 and the like attached to the fixed platen 4 are arranged so as to surround the solenoid coil 2. Drive rod 3
Is exposed to the outside through a bearing 7 provided on a through plate 6 attached to one end of the tubular case 5, and the deformation (magnetostriction) of the magnetic body 1 is taken out as a displacement output of a magnetostrictive actuator. There is. The magnetic body 1, the drive rod 3, the penetrating plate 6, the cylindrical case 5, and the fixed plate 4 constitute a closed magnetic circuit of the control magnetic field generated by the solenoid coil 2. A permanent magnet 8 is attached to the stationary platen 4, and a bias magnetic field is applied to the magnetic body 1 in advance by the permanent magnet 8. In addition, the through plate 6 and the drive rod 3
A preload spring 10 made of a disc spring, a coil spring, or rubber is sandwiched between the flange 9 and the
As a result, a preload is applied to the magnetic body 1 and an initial displacement is given.

In the magnetostrictive actuator having such a structure, since the drive rod 3 connected to the magnetic substance 1 having a magnetostriction, which is a displacement generating means, is supported by the bearing 7, the actuator is caused by friction on the sliding surface of the bearing 7. There was a problem that the output loss of the

The control magnetic field and bias magnetic field generated by the solenoid coil 2 and the permanent magnet 8 are between the drive rod 3 and the bearing 7, or between the drive rod 3 and the tubular case 5 when the bearing 7 is not installed. Since there is a gap in the magnetic field, when the magnetic field generating means is surrounded by a closed magnetic circuit using the cylindrical case 5 like the above-mentioned magnetostrictive actuator, the magnetic circuit is disconnected at the gap. As a result, the efficiency of the magnetic circuit is reduced, which is a cause of output loss of the actuator. Further, since a leakage magnetic field is generated in the gap portion, there is a problem in that when this actuator is used in an electronic device or the like, it causes malfunction of the device.

Further, when a disc spring is used as a means for applying a preload to the magnetic substance 1 having magnetostriction, friction occurs on the mating surface and the fixed surface of the disc spring, and when it is made of rubber, However, there is a problem that the output loss of the actuator becomes large due to the non-linear behavior of the spring characteristics. Further, if the preload generating means using a disc spring, a coil spring, rubber or the like is formed inside the actuator, there is a problem that the entire structure of the actuator becomes large.

[0009]

As described above, the conventional magnetostrictive actuator has various problems such as output loss and size increase of the actuator itself. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a magnetostrictive actuator in which the output loss of the actuator is small and the size is not increased even by the preload generation means. It is another object of the present invention to provide a magnetostrictive actuator which constitutes an efficient closed magnetic circuit and has a small leakage magnetic field.

[0010]

In order to achieve the above object, according to the present invention, a displacement generating means made of a magnetic material having magnetostriction and a displacement generating means connected to the displacement generating means are movable in the displacement direction of the displacement generating means. A movable member, a magnetic field generating means arranged around the displacement generating means for applying a magnetic field to the displacement generating means, and a magnetic circuit configuration for accommodating the displacement generating means and the magnetic field generating means to form a closed magnetic circuit. In a magnetostrictive actuator comprising a member, a magnetostrictive actuator characterized by having a flexible connecting member for connecting the movable member and the magnetic circuit component member, and by deforming the connecting member in advance. The magnetostrictive actuator is characterized in that a preload is applied to the displacement generating means.

On the other hand, a displacement generating means made of a magnetic substance having magnetostriction, a movable member connected to the displacement generating means and movable in the displacement direction of the displacement generating means, and disposed around the displacement generating means. A magnetostrictive actuator comprising magnetic field generating means for applying a magnetic field to displacement generating means, and a magnetic circuit constituent member for accommodating the displacement generating means and the magnetic field generating means to constitute a closed magnetic circuit, wherein the movable member and the At least one of a plurality of flexible connecting members provided in parallel with respect to the displacement direction of the displacement generating means for connecting with the magnetic circuit component member and a region formed between the plurality of connecting members. A magnetostrictive actuator comprising a magnetic fluid sealed in one place, and a preload is applied to the displacement generating means by deforming the connecting member in advance. It is provided together also the magnetostrictive actuator, characterized by comprising.

[0012]

According to the present invention having the above structure,
By providing a flexible connecting member that connects the movable member connected to the displacement generating means and the magnetic circuit constituent member that houses the displacement generating means and the magnetic field generating means and constitutes a closed magnetic circuit, the conventional problem is solved. The problem of friction between the movable member and the bearing that supports it has been eliminated, and since there is no gap between the movable member and the magnetic circuit constituent member, the magnetic circuit is not cut and the efficiency is improved. It is possible to form a closed magnetic circuit having good magnetic field around the magnetic body.

Further, by preliminarily deforming the connecting member and applying a preload to the displacement generating means, the preload generating means can be configured as a part of the casing constituting the closed magnetic circuit of the magnetostrictive actuator. The magnetostrictive actuator can be miniaturized without requiring an independent space for newly installing the preload generating means.

[0014]

Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic sectional view showing a first embodiment of a magnetostrictive actuator according to the present invention. In this example,
A rod-shaped magnetic body 11 having magnetostriction as a displacement generating means, and a magnetic body 11 for applying a control magnetic field to the magnetic body 11.
A solenoid coil 12 serving as a magnetic field generating means arranged around the magnetic body, a drive rod 13 serving as a movable member for transmitting a displacement output of a magnetostrictive actuator connected to one end of the magnetic body 11, and connected to the other end of the magnetic body. Fixed plate 14
It is composed of a cylindrical case 15 and the like which is attached to the stationary platen 14 and is arranged so as to surround the solenoid coil 12. A permanent magnet 16 is attached to the fixed platen 14 to apply a bias magnetic field to the magnetic body 11. In addition,
The permanent magnet 16 may not be provided. The drive rod 13 and the tubular case 15 have a flexible connecting member 1
7 are linked together. The connecting member 17 is connected to the drive rod 13 and the cylindrical case 15 so as to be flexible in the driving direction of the magnetostrictive actuator and rigid in the direction orthogonal to the driving direction. Here, the connecting member 17
The plate thickness is set such that the spring rigidity of the connecting member 17 in the driving direction of the magnetostrictive actuator is sufficiently softer than the spring rigidity of the magnetic body 11 in the same direction. That is, when the magnetostrictive actuator is driven, the connecting member 17 causes the magnetic body 11 to move.
The structure does not affect the displacement output of.

According to this embodiment, there is no problem of friction between the drive rod 13 and the bearing that supports it, which has been a problem in the past. Further, since there is no gap between the drive rod 13 and the cylindrical case 15, the magnetic circuit is not cut, and an efficient closed magnetic circuit can be constructed around the magnetic body 11. Therefore, the loss of displacement output of the magnetostrictive actuator can be significantly reduced. Further, since the leakage magnetic field to the outside of the magnetostrictive actuator can be reduced, even when the magnetostrictive actuator is mounted on an electronic device or the like, there is no possibility that the device malfunctions.

On the other hand, although not shown, similar effects can be obtained even when the permanent magnets 16 for applying a bias magnetic field are attached to both sides of the magnetic body 11. FIG. 2 is a schematic sectional view showing a second embodiment of the magnetostrictive actuator according to the present invention. In the present embodiment, a plurality of connecting members 18 having a plate thickness smaller than that of the connecting member 17 in the first embodiment described above are arranged closer to the magnetic body 11 than the connecting member 17, and the drive rod 13 and the tubular case 15 are provided. It has a structure that is attached so as to connect with. Here, the spring rigidity of the connecting portion 23 including the plurality of connecting members 17 and 18 in the driving direction of the magnetostrictive actuator is set to be sufficiently softer than the spring rigidity of the magnetic body 11 in the same direction.

According to this embodiment, the contact area between the drive rod 13, the tubular case 15 and the connecting portion 23 is increased,
Since the efficiency of the closed magnetic circuit is improved and the efficiency of applying the magnetic field to the magnetic body 12 is improved, the output loss of the magnetostrictive actuator can be further reduced. It is also possible to further reduce the leakage magnetic field to the outside of the magnetostrictive actuator.

3 and 4 are an overall sectional view and a partial sectional view, respectively, showing a third embodiment of the magnetostrictive actuator according to the present invention. In the present embodiment, two connecting members 17 described above are provided substantially in parallel, and each connecting member 17a,
The outer peripheral side of 17b is connected to the fixed ring 19 connected to the end of the cylindrical case 15, and the inner peripheral side is connected to the drive rod 13. A magnetic fluid 21 is enclosed in a region surrounded by these two connecting members 17a and 17b from an injection port 20 provided in the fixing ring 19. In addition, the connecting members 17a, 17 relating to the driving direction of the magnetostrictive actuator
The spring rigidity of the connecting portion 24 composed of b and the magnetic fluid 21 is
It is set sufficiently softer than the spring rigidity of the magnetic body 11 in the same direction. That is, the connecting portion 24 does not affect the displacement output of the magnetic body 11 when the magnetostrictive actuator is driven.

According to this embodiment, as in the first embodiment,
There is no problem of friction between the drive rod 13 and the bearing. Further, since there is no gap between the drive rod 13 and the cylindrical case 15, the magnetic circuit is not cut off,
An efficient closed magnetic circuit can be constructed around the magnetic body 11. Therefore, it is possible to significantly reduce the output loss of the magnetostrictive actuator. Further, since the leakage magnetic field to the outside of the magnetostrictive actuator can be reduced, even when the magnetostrictive actuator is mounted on an electronic device or the like, there is no possibility that the device malfunctions. Further, since the magnetic fluid 21 is enclosed in the region surrounded by the connecting member 18, the contact area between the drive rod 13 and the case 15 and the connecting portion 24 becomes large, so that the closed magnetic circuit as in the second embodiment. Efficiency is improved and the efficiency of applying a magnetic field to the magnetic body 12 is further improved, so that the output of the magnetostrictive actuator can be improved.

FIG. 5 is a schematic sectional view showing a fourth embodiment of the magnetostrictive actuator according to the present invention. In the present embodiment, the outer peripheral portion of the connecting member 17 is fixed to the fixing ring 19 in the first embodiment of the present invention, and the length of the tubular case 15 is shortened so that the end portion of the tubular case 15 of the fastening ring 19 is fixed. By moving the connection position of the connection member to the fixed platen 14 side, the connecting member 17
Is preliminarily subjected to bending deformation. By applying bending deformation to the connecting member 17, the drive rod 13 is pressed toward the magnetic body 11 by its restoring force, and a preload is applied in the axial direction of the magnetic body 11.

According to this embodiment, since the preload generating means is conventionally constructed as an independent structure, it is constructed as a part of the closed magnetic circuit of the magnetostrictive actuator.
An independent space for newly installing the preload generating means is not required, the magnetostrictive actuator can be downsized, and an efficient closed magnetic circuit can be configured. Further, it is possible to change the preload amount by moving the installation position of the fixing ring 22.

Although not shown, the connecting members 17a, 1a
Similar effects can be obtained when the initial shape of 7b is not a flat plate but a conical shape or a curved shape. FIG. 6 is a schematic sectional view showing a fifth embodiment of the magnetostrictive actuator according to the present invention. This embodiment is the same as the fixing ring 19 in the fourth embodiment of the present invention.
By arranging and connecting the two connecting members 17a and 17b to the drive rod 13, the drive rod 13 is supported at two positions in the axial direction.

According to this embodiment, even if an external force in the bending direction is applied to the driving rod 15, the two connecting members 17 are connected.
Since the external force can be supported by a and 17b, it is possible to reduce the influence of the external force on the displacement output of the magnetostrictive actuator. Other effects are similar to those of the fourth embodiment.

In this embodiment, the number of connecting members is not limited to two, and a plurality of connecting members can achieve the same effect. FIG. 7 is a sixth view of the magnetostrictive actuator according to the present invention.
It is a schematic sectional drawing which shows an Example. This embodiment is the same as the fifth embodiment of the present invention, except that the injection port 2 provided in the fixing ring 19 is provided in the region surrounded by the two connecting members 17a and 17b.
The magnetic fluid 21 is sealed from zero.

According to this embodiment, as in the fifth embodiment,
The magnetostrictive actuator can be downsized without the need for an independent space for newly installing the preload generation means, and a small and efficient closed magnetic circuit can be configured, such as a bearing or a spring structure. There is no problem of friction. Further, it is possible to change the preload amount by moving the installation position of the fixing ring 19. further,
Similar to the third embodiment, since the magnetic fluid 21 is enclosed in the area surrounded by the connecting members 17a and 17b, the contact area between the drive rod 13 and the case 15 and the connecting portion 24 becomes large, so that the closed magnetic circuit is formed. Efficiency is improved and the efficiency of applying a magnetic field to the magnetic body 12 is further improved, so that the output of the magnetostrictive actuator can be improved.

FIG. 8 is a schematic sectional view showing a seventh embodiment of the magnetostrictive actuator according to the present invention. In this embodiment, the drive rods 13a and 13b and the connecting portions 24a and 24b are provided at both ends of the magnetic body 11 in the sixth embodiment of the present invention, and the fixed plate and the permanent magnet for applying the bias magnetic field are not provided. It was done. Here, the connecting portion 24a (2
4b) is the drive rod 13a (13b) and the cylindrical case 1
Two flexible connecting members 17a for connecting with 5
(17b), 18a (18b) and a magnetic fluid 21a (21b) enclosed between them.

Also in this embodiment, a part of the closed magnetic circuit of the magnetostrictive actuator can be constructed as the preload generating means, and a small and efficient closed magnetic circuit can be constructed without friction by the preload generating means. it can. Although not shown, the same effect can be obtained even when a bias magnetic field is applied by providing a permanent magnet here.

FIG. 9 is a schematic sectional view showing an eighth embodiment of the magnetostrictive actuator according to the present invention. The present embodiment is a modification of the fixing method of the magnetic body 11 on the side of the fixed plate 14 in the fourth embodiment of the present invention. In this embodiment, a connecting member 25 is also provided on the side of the stationary plate 14 of the tubular case 15 to support the magnetic body 11 via the connecting members 17 and 25 at two places, and at the center of the stationary plate 14. The magnetic body 11 is driven by the push screw 26 installed on the drive rod 1
A structure is adopted in which a predetermined preload is applied to the magnetic body 11 by pushing it out to the 3 side.

According to this embodiment, by adjusting the pushing amount by the push screw 26, the preload amount can be easily changed with a small and simple structure, and the friction caused by the preload generating means can be reduced. In addition, a small and efficient closed magnetic circuit can be configured. Further, even when an axial force is applied to the magnetic body 11 due to loading of a heavy object or the like, the preload can be adjusted to a predetermined value. Further, if the plate thickness of the connecting member 25 on the fixed platen 14 side is increased, the rigidity of the support structure on the reaction force side of the displacement output can be increased.

FIG. 10 is a schematic sectional view showing a ninth embodiment of the magnetostrictive actuator according to the present invention. In this example,
The fixing method of the magnetic body 12 on the side of the fixed plate 14 in the sixth embodiment of the present invention is changed. A connecting member 17 is also provided on the stationary plate 14 side of the cylindrical case 15, and the magnetic body 11 is supported via the connecting members 17 at two locations, and a magnetic force is provided by a push screw 26 installed in the center of the stationary plate 14. By pushing the body 11 to the driving side, the magnetic body 11
The structure is such that a predetermined preload is applied to.

According to this embodiment, as in the case of the above-mentioned eighth embodiment, by adjusting the pushing amount by the push screw 25, the preload amount can be easily changed with a small and simple structure. In addition, there is no friction due to the preload generation means, and it is possible to configure a small and efficient closed magnetic circuit. Further, even when an axial force is applied to the magnetic body 12 due to loading of a heavy object or the like, the preload can be adjusted to a predetermined value. Further, if the plate thickness of the connecting member 25 on the fixed platen 14 side is increased, the rigidity of the support structure on the reaction force side of the displacement output can be increased.

In the present invention described above, various modifications and combinations (for example, a combination of the second embodiment and the third embodiment) are possible within the scope of the invention. Needless to say.

[0033]

As described above, according to the present invention,
By constructing an efficient closed magnetic circuit, it is possible to significantly reduce the loss of displacement output of the magnetostrictive actuator and to reduce the leakage magnetic field to the outside of the magnetostrictive actuator. Even when mounted on a device or the like, there is no risk of the device malfunctioning. Further, it is possible to reduce the size of the magnetostrictive actuator without requiring an independent space for newly installing the preload generating means.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing a first embodiment of a magnetostrictive actuator according to the present invention.

FIG. 2 is a schematic cross-sectional view showing a second embodiment of the magnetostrictive actuator according to the present invention.

FIG. 3 is an overall sectional view showing a third embodiment of the magnetostrictive actuator according to the present invention.

FIG. 4 is a partial sectional view showing a third embodiment of the magnetostrictive actuator according to the present invention.

FIG. 5 is a schematic sectional view showing a fourth embodiment of the magnetostrictive actuator according to the present invention.

FIG. 6 is a schematic sectional view showing a fifth embodiment of the magnetostrictive actuator according to the present invention.

FIG. 7 is a schematic sectional view showing a sixth embodiment of the magnetostrictive actuator according to the present invention.

FIG. 8 is a schematic sectional view showing a seventh embodiment of the magnetostrictive actuator according to the present invention.

FIG. 9 is a schematic sectional view showing an eighth embodiment of the magnetostrictive actuator according to the present invention.

FIG. 10 is a schematic sectional view showing a ninth embodiment of the magnetostrictive actuator according to the present invention.

FIG. 11 is a schematic sectional view showing a conventional magnetostrictive actuator.

[Explanation of symbols]

 1,11 Magnetic material (displacement generating means) 2,12 Solenoid coil (magnetic field generating means) 3,13 Driving rod (movable member) 4,14 Fixed platen 5,15 Cylindrical case (magnetic circuit constituent member) 6,16 Permanent Magnet 10 Preload spring 17, 18 Connecting member 19 Fixing ring 20 Pouring port 21 Magnetic fluid

Front Page Continuation (72) Inventor Tadahiko Kobayashi 1 Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa Toshiba Corporation R & D Center (72) Inventor Isao Sakai 1 Komukai-shiba-cho, Saiwai-ku, Kawasaki-shi, Kanagawa Incorporated company Toshiba Research and Development Center

Claims (4)

[Claims] 1. A displacement generating means made of a magnetic material having magnetostriction, a movable member connected to the displacement generating means and movable in a displacement direction of the displacement generating means, and arranged around the displacement generating means. A magnetostrictive actuator comprising magnetic field generating means for applying a magnetic field to displacement generating means, and a magnetic circuit constituent member for accommodating the displacement generating means and the magnetic field generating means to constitute a closed magnetic circuit, wherein the movable member and the A magnetostrictive actuator comprising a flexible connecting member for connecting a magnetic circuit constituent member. 2. The magnetostrictive actuator according to claim 1, wherein a preload is applied to the displacement generating means by deforming the connecting member in advance. 3. A displacement generating means made of a magnetic material having magnetostriction, a movable member connected to the displacement generating means and movable in the displacement direction of the displacement generating means, and disposed around the displacement generating means. A magnetostrictive actuator comprising magnetic field generating means for applying a magnetic field to displacement generating means, and a magnetic circuit constituent member for accommodating the displacement generating means and the magnetic field generating means to constitute a closed magnetic circuit, wherein the movable member and the At least one of a plurality of flexible connecting members provided in parallel with the displacement direction of the displacement generating means for connecting with the magnetic circuit constituent member, and at least one of regions formed between the plurality of connecting members. A magnetostrictive actuator, comprising: a magnetic fluid sealed in one place. 4. The magnetostrictive actuator according to claim 3, wherein a preload is applied to the displacement generating means by deforming the connecting member in advance.