JP3288202B2 - Magnetostrictive actuator - Google Patents

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 magnetic material that generates magnetostriction when an external magnetic field is applied.

[0002]

2. Description of the Related Art As an actuator for generating vibration and displacement, an electromagnetic actuator (so-called voice coil motor) using the principle of a speaker is known. Further, a piezoelectric actuator for applying a control voltage to a piezoelectric element such as PZT or an actuator utilizing a magnetostriction phenomenon is also known.

By the way, many precision processing apparatuses and precision measurement apparatuses extremely dislike the ground vibration transmitted through a mounting table. Recently, to install these devices,
Attempts have been made to provide vibration isolation by actively controlling a vibration isolation table in which a mounting table and an actuator are combined. Such a vibration isolator can also be applied to a vibration isolator for preventing vibrations generated by rotating machinery such as an electric motor from being transmitted to the surrounding environment.

It is desired that an actuator for such a purpose be small, capable of obtaining a large force, and in some cases, capable of supporting a large weight and reliable. As an actuator satisfying such a demand, a magnetostrictive actuator using a magnetostrictive material as an element has attracted attention.

As shown in FIG. 13, a magnetostrictive actuator generally has a magnetostrictive element 100 having one end fixed and the other end provided at a free end.
An output shaft 101 for taking out the displacement of the free end of the output as an output, a movable yoke 102 serving as a magnetic circuit component for allowing a displacement of the magnetostrictive element 100 and forming a magnetic circuit passing through the magnetostrictive element 100 in series, a cylinder A yoke 103 and a fixed yoke 104, bias magnetic field applying permanent magnets 105 and 106 for applying a bias magnetic field to the magnetostrictive element 100 via these magnetic circuit components, and are arranged around the magnetostrictive element 100 and applied to the magnetostrictive element 100. And a coil 108 that constitutes a control magnetic field applying electromagnet that controls the amount of displacement obtained from the free end by controlling the strength of the applied magnetic field.

As the magnetostrictive element 100, Ni-based alloys, Fe-Al alloys, and ferrite-based alloys are mainly used, but recently, a displacement larger by one digit or more than the above alloy materials can be generated. Rare earth metal-transition metal alloys have also been reported.

The relationship between the magnetic field and strain in a magnetostrictive element is
In general, the higher the applied magnetic field, the longer the applied magnetic field is based on the case where no magnetic field is applied. However, irrespective of the direction of the applied magnetic field, it has the property that, as the absolute amount of the applied magnetic field is larger, the one that expands expands and the one that contracts contracts. For example, the relationship between the magnetic field of a magnetostrictive element that expands as the applied magnetic field increases and the strain is as shown in FIG. Therefore, in this type of actuator,
In general, in order to facilitate the control of the generated displacement, the relationship between the control magnetic field and the generated displacement is made linear. That is,
As shown in FIG. 15, a certain bias magnetic field is applied, and in this state, the amount of displacement is controlled by controlling the strength of the magnetic field applied to the magnetostrictive element.

As means for controlling the strength of the magnetic field applied to the magnetostrictive element, as shown in FIG.
In general, a method is used in which a coil 108 is arranged around the coil 108 and the direction and magnitude of a current flowing through the coil 108 are controlled. As means for applying a bias magnetic field, a method using the control coil for bias,
There is a method using a permanent magnet. In a method using a control coil together, it is necessary to always supply a direct current to the coil, so that the coil generates a large amount of heat and is not suitable for long-time use. For this reason, a bias magnetic field is generally applied by the permanent magnets 105 and 106 as shown in FIG.

However, the conventional magnetostrictive actuator configured as described above has the following problems. That is, in the conventional actuator, in order to allow the displacement of the magnetostrictive element 100, the gap 1 is provided between the movable yoke 102 and the cylindrical yoke 103 which are magnetic circuit components.
10 are provided. Since the gap 110 has a relatively large magnetic resistance, it not only causes magnetic leakage, but also makes it difficult to uniformly apply the bias magnetic field generated by the permanent magnets 105 and 106 to the magnetostrictive element 100. , The linear range with good controllability was narrowed.

Further, in order to take out the displacement of the free end of the magnetostrictive element 100 as an output, it is necessary to support the output shaft 101 provided on the free end side movably in a displacement direction by some means. As the supporting means, in the conventional actuator shown in FIG.
A so-called slide bearing system in which the guide support member 112 guides and supports the slide bearing 1 through the support member 1 is adopted. However, in such a supporting method, the output shaft 101 and the guide supporting member 112
There is a problem that smooth and responsive control cannot be performed due to the solid frictional resistance between the two.

[0011]

As described above, in the conventional magnetostrictive actuator, the bias magnetic field by the permanent magnet becomes non-uniform due to the magnetic resistance due to the air gap between the movable part and the fixed part, and the range in which the controllability is good. There is a problem that the magnetic leakage is increased while being narrowed.

Further, there is a problem that solid friction is generated in the sliding bearing portion inside the actuator due to expansion and contraction of the magnetostrictive element, and control performance is deteriorated. An object of the present invention is to provide a magnetostrictive actuator capable of solving the above-mentioned problems without increasing the size.

[0013]

According to the first aspect of the present invention, a displacement generating means made of a magnetic material having magnetostriction, and a magnetic field applied to the displacement generating means are provided around the displacement generating means. A magnetic field generating means for storing the displacement magnetic means, and a closed magnetic circuit constituting member accommodating the displacement generating means and forming a closed magnetic circuit together with the displacement generating means. A component member is constituted by a bottomed inner cylinder member, and a bottomed outer cylinder member arranged concentrically while keeping a gap with the outer periphery of the inner cylinder member, and a bottom portion of the inner cylinder member One end and the other end of the displacement generating means are connected to an inner surface and an inner surface of a bottom portion of the outer cylinder member, respectively.

In the actuator according to the first aspect of the present invention, the magnetic circuit component member includes a bottomed inner cylinder member and a bottomed outer cylinder member disposed so as to cover the outer periphery from the opening side. Since the inner cylinder member and the outer cylinder member are opposed to each other with a minute gap therebetween, the facing area between the inner cylinder member and the outer cylinder member can be increased. Therefore, the magnetic resistance in the gap between the inner cylinder member and the outer cylinder member can be made extremely small, and magnetic leakage can be prevented, and the bias magnetic field can be made uniform and the responsive output displacement range can be widened. .

According to a second aspect of the present invention, the relative displacement between the inner cylinder member and the outer cylinder member is caused by elastic deformation in a gap between the outer periphery of the inner cylinder member and the inner periphery of the outer cylinder member. Is provided.

In the actuator according to the second aspect of the present invention, guide means for permitting relative movement between the inner cylinder member and the outer cylinder member by elastic deformation is interposed in a gap between the inner cylinder member and the outer cylinder member. Therefore, in the relative movement between the inner cylinder member and the outer cylinder member accompanying the expansion and contraction of the displacement generating means (magnetostrictive element),
Due to the elastic deformation of the guide means, the inner cylinder member and the outer cylinder member do not come into direct contact with each other, so that both members can relatively move without generating solid friction, and the controllability of the output displacement of the actuator improves.

According to a sixth aspect of the present invention, there is provided a displacement generating means made of a magnetic material having magnetostriction, and a magnetic field generating means disposed around the displacement generating means for applying a magnetic field to the displacement generating means. A bottomed cylindrical first member accommodating the displacement generating means and the magnetic field generating means;
A second member for forming a closed magnetic circuit together with the member and the displacement generating means, one end of which is attached to the first member, and the other end of which is attached to the second member; A thin plate member disposed in a direction substantially perpendicular to the direction, wherein one end of the displacement generating means is connected to a first member, and the other end is connected to a second member, and the second end is connected to the second member by elastic deformation of the thin plate member. The first member and the second member are configured to be relatively movable.

In the actuator according to the sixth aspect, the ends of the thin plate members are respectively attached to the first member having a bottomed cylindrical shape and the second member forming a magnetic circuit together with the first member. Is that the thin plate member has one end fixed to the first member and the other end fixed to the second member in a direction substantially perpendicular to the displacement direction of the displacement generating means (magnetostrictive element). The first member and the second member can move relative to each other without causing solid friction. Therefore, similarly to the actuator of the second aspect, the controllability of the output displacement of the actuator is improved. Further, according to this structure, even when a force in a direction perpendicular to the displacement direction of the displacement generating means, that is, a shear force is applied, the shear force is received by the tensile rigidity in the direction along the surface of the thin plate member. The magnetostrictive element) can be prevented from being damaged by receiving a shearing force.

According to a ninth aspect of the present invention, a displacement generating means made of a magnetic material having magnetostriction, and a magnetic field generating means disposed around the displacement generating means for applying a magnetic field to the displacement generating means And a closed magnetic circuit component that houses the displacement generating means and the magnetic field generating means and forms a closed magnetic circuit together with the displacement generating means, wherein the closed magnetic circuit component has a bottomed bottom. -Shaped inner cylinder member, and a bottomed outer cylinder member arranged concentrically while maintaining a gap with the outer periphery of the inner cylinder member, and a bottom inner surface side of the inner cylinder member and the outer cylinder One end and the other end of the displacement generating means are respectively connected to the bottom inner surface side of the member, and pressurization is applied between the inner cylinder member and the outer cylinder member in a direction to shrink the displacement generating means. Pressurizing member It is characterized in that the.

In the actuator according to the ninth aspect, a pressurizing member for applying a pressurizing force in a direction to contract the displacement generating means is provided between the inner cylindrical member and the outer cylindrical member. By the way, the displacement generating means (magnetostrictive element) increases the amount of expansion and contraction by applying a compressive force in advance in the direction of the expansion and contraction axis. When it is larger than this, the amount of expansion and contraction displacement decreases. Therefore, when trying to control the movement of the controlled object in the horizontal direction, it is desirable to apply a compressive force to the magnetostrictive element in particular because the own weight of the controlled object does not act in the direction of gravity of the actuator. As described in the invention, an appropriate compressive force can be applied to the magnetostrictive element by using the preload member. Therefore, the configuration is particularly suitable for the case where the movement of the control target is to be controlled in the horizontal direction.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a magnetostrictive actuator according to the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 is a sectional view of a magnetostrictive actuator according to a first embodiment of the present invention.

This actuator is roughly divided into a cylindrical casing 1, a displacement generating section 2 accommodated in the casing 1 coaxially with the casing 1, and a magnetic field applying section for applying a magnetic field to the displacement generating section 2. 3 is comprised.

The casing 1 comprises an inner cylinder 4 and an outer cylinder 5 made of a material having high magnetic permeability such as pure iron. The inner cylindrical body 4 includes a cylindrical member 6 and a sealing member 7 formed in a disk shape and fixed to the cylindrical member 6 so as to close an opening on one end side of the cylindrical member 6. Similarly, the outer cylindrical body 5 includes a cylindrical member 8 and a sealing member 9 formed in a disk shape and fixed to the cylindrical member 8 so as to close an opening on one end side of the cylindrical member 8.

Then, the casing 1 is inserted into the inner cylinder 4 from the opening of the outer cylinder 5 in a state where the opening of the inner cylinder 4 and the opening of the outer cylinder 5 face each other. The outer periphery of the cylindrical member 6 of the body 4 and the inner periphery of the cylindrical member 8 of the outer cylinder 5 are arranged so as to face each other with a small gap 10 therebetween.

The displacement generator 2 has a disk-shaped permanent magnet 11 whose S pole face is closely attached to the inner surface of the sealing member 9 of the outer cylinder 5, and one end side of which is an N pole face of the permanent magnet 11. A cylindrical magnetostrictive element 12 which is mounted closely to the casing 1 and arranged coaxially with the permanent magnet 11;
And a disk-shaped permanent magnet 13 provided with the N pole face closely attached to the inner surface of the sealing member 7 of the inner cylinder 4 on the upper surface of the drawing.

The magnetic field applying unit 3 includes the above-described permanent magnet 11,
13 and a coil 14 disposed concentrically with the magnetostrictive element 12 around the magnetostrictive element 12. Coil 14
Is wound around the outer periphery of a bobbin 15 formed of a non-magnetic material such as resin or aluminum. A flange portion 16a located below the winding frame 15 in the figure is fixed to the inner surface of the sealing member 9 of the outer cylinder 5 with a screw (not shown) or the like.

In the casing 1, annular grooves 17, 18 are formed on the outer periphery of the cylindrical member 6 of the inner cylindrical body 4, and the inner cylindrical body 4 and the outer cylindrical body are formed in these annular grooves 17, 18. The elastic support rings 19 and 20 made of rubber or the like are elastically supported so as to allow the relative movement in the axial direction while restricting the relative movement in the direction perpendicular to the axis with respect to the axis 5. I have. The annular grooves 17 and 18 are formed on the outer periphery of the cylindrical member 6 of the inner cylinder 4, but may be formed on the cylindrical member 8 of the outer cylinder 5.

In this embodiment, the annular groove 17,
Elastic support rings 19 and 20 having a square cross section are mounted in the inside 18. Since the elastic support rings 19 and 20 do not require a sealing function (a function of sealing between the cylindrical member 6 and the cylindrical member 8), it is not necessary to mount the elastic support rings 19 and 20 firmly by compression.

The inner cylinder 4 and the outer cylinder 5 have a function as a closed magnetic circuit for the coil 14 and the permanent magnets 11 and 13, and the gap 10 is made as narrow as possible from the viewpoint of reducing magnetic resistance. It is desirable.

The magnetostrictive element 12 is made of a Ni alloy, Fe
It is formed of a magnetic material having magnetostrictive characteristics, such as an Al alloy, a ferrite alloy, and a rare earth metal-transition metal alloy. With the above configuration, the magnetic flux emitted from the N pole of the permanent magnet 11 is transmitted to the magnetostrictive element 12 → the permanent magnet 13 → the sealing member 7 → the cylindrical member 6 → the cylindrical member 8 → the sealing member 9 → the permanent magnet 1
Pass by the first route. That is, 1
One closed magnetic circuit is formed. And the permanent magnet 1
Reference numerals 1 and 13 denote magnetostrictive elements 12
Has a function of applying a bias magnetic field to the In this embodiment, since the closed magnetic circuit is provided with the illustrated polarity, a magnetic field having a strength obtained by adding the magnetic field applied based on the permanent magnet 11 and the magnetic field applied based on the permanent magnet 13 is obtained. The bias magnetic field is applied to the magnetostrictive element 12 in the axial direction.

By the application of the bias magnetic field, the magnetostrictive element 12 is held in a state of being extended in the axial direction by a predetermined amount or contracted in the axial direction by a predetermined amount, as compared with the case where no bias magnetic field is applied. Whether to expand or contract is determined by the properties of the material constituting the magnetostrictive element 12, but here, for convenience of explanation, the magnetostrictive element 12 is held in a state where the magnetostrictive element 12 is extended by a predetermined amount in the axial direction by applying a bias magnetic field. It will be described as having been performed.

Since the coil 14 is arranged concentrically with the magnetostrictive element 12, the magnetic field generated by the coil 14 increases or decreases the strength of the magnetic field applied to the magnetostrictive element 12. Therefore, a current in a direction in which the strength of the magnetic field applied to the magnetostrictive element 12 becomes larger than the bias magnetic field level is applied to the coil 14.
, The magnetostrictive element 12 further extends by an amount corresponding to the increase in the applied magnetic field. Conversely, when a current is applied to the coil 14 such that the intensity of the magnetic field applied to the magnetostrictive element 12 is smaller than the bias magnetic field level, the magnetostrictive element 12 contracts by an amount corresponding to the decrease in the applied magnetic field. Therefore, by controlling the current flowing through the coil 14, the magnetostrictive element 12
Can be expanded and contracted. The expansion and contraction displacement of the magnetostrictive element 12 can be taken out as a relative displacement between the inner cylinder 4 and the outer cylinder 5. For example, if the outer cylinder 5 is arranged on the fixed portion side, the displacement of the inner cylinder 4 can be transmitted to a load (not shown), and the function as an actuator can be exhibited here.

In the case of this embodiment, elastic support rings 19 and 20 are interposed between the cylindrical member 6 forming the inner cylinder 4 and the cylindrical member 8 forming the outer cylinder 5, Since the elastic support rings 19 and 20 support the inner cylindrical body 4 and the outer cylindrical body 5 so that the relative movement in the axial direction can be freely performed, the support is performed using a slide bearing. Unlike this, no solid friction occurs. Therefore, the controllability of the actuator can be improved.

In the closed magnetic circuit, the gap 10 between the cylindrical member 6 and the cylindrical member 8 contributes to an increase in magnetic resistance.
0, the opposing area between the cylindrical member 6 and the cylindrical member 8 is large, that is, the cylindrical member 6 and the cylindrical member 8 are arranged so as to overlap each other with the minute gap 10 therebetween, and the opposing area is set to be extremely large. I have. Therefore, the magnetic resistance of the gap 10 can be reduced without increasing the size as compared with the conventional actuator, and the bias magnetic field applied to the magnetostrictive element 12 can be made uniform in the axial direction to improve the controllability. The displacement range can be increased and magnetic leakage to the outside can be prevented.

Although the cross section of the elastic support ring is square in the embodiment shown in FIG. 1, the cross section may be a circle or an ellipse such as an O-ring. Further, it is not necessary to form a complete ring around the circumference of the cylindrical member, and a plurality of elastic support members may be used so as to support the circumference of the cylindrical member at a plurality of locations. It is desirable to support at multiple target locations.

Further, a bias magnetic field is applied to the magnetostrictive element 12 by using the permanent magnets 11 and 13. However, the permanent magnet is omitted by constantly flowing a DC current corresponding to the amount of the generated bias magnetic field to the coil 14. You may do it. Further, the coil 14 is fixed to the sealing member 9 of the outer cylinder body 5 by a flange portion 16a located below the bobbin 15 in the drawing, but is replaced with this, and is positioned above the bobbin 15 in the drawing. The inner flange 4 may be fixed to the sealing member 7 of the inner cylinder 4 by the flange 16b. (Second Embodiment) FIG. 2 is a sectional view of a magnetostrictive actuator according to a second embodiment of the present invention.

As in the first embodiment, this actuator is also roughly divided into a double cylindrical casing 1, a displacement generating section 2 accommodated in the casing 1 coaxially with the casing 1, and a displacement generating section 2 And a magnetic field applying unit 3 for applying a magnetic field to the magnetic field.

The casing 1 is used to connect the inner cylinder 4, the outer cylinder 5, and the inner cylinder 4 and the outer cylinder 5 which are characteristic of the second embodiment shown in FIG. Are formed by thin plate-shaped guide members 21 and 22.

The second embodiment is different from the first embodiment in that the relative thickness between the inner cylinder 4 and the outer cylinder 5 due to the expansion and contraction of the magnetostrictive element 12 is reduced by the thin plate-like guide members 21 and 22. The feature is that it guides and supports the movement. The configuration of the second embodiment will be described below with reference to FIGS.

The inner cylindrical member 4 includes a cylindrical member 6, a sealing member 7 formed in a disk shape and fixed to the cylindrical member 6 so as to close an opening at one end of the cylindrical member 6, and a sealing member 7. A guide member fixing ring 28 fixed with a screw (not shown) across the inner flange portion 25 of the guide member 21 so as to fill an L-shaped cross section formed around the upper part of the drawing;
A guide member fixing ring 30 is fixed to the lower end surface of the cylindrical member 6 in the drawing by an unillustrated screw with the inner flange 25 of the guide member 22 interposed therebetween.

On the other hand, the outer cylindrical body 5 is formed in a disk shape with the cylindrical member 8 sandwiching the outer flange 26 of the guide member 22 so as to close the lower end opening of the cylindrical member 8 in the drawing. A fixed sealing member 9 and a yoke member 35 which is formed in a disk shape with the periphery thereof maintaining a slight gap 10 from the inner surface of the opening of the inner cylinder 4 and is fixed to the upper surface side of the sealing member 9 in the drawing.
And a guide member fixing ring 29 fixed to the upper end surface of the cylindrical member 8 in the figure with a screw (not shown) across the outer flange portion 26 of the guide member 21.

As shown in FIG. 3, the guide plates 21 and 22 are formed in such a manner that an inner flange portion 25 and an outer flange portion 26 formed in a ring shape are connected by four thin plate-shaped connection portions 27. The bending deformation of the connecting portion 27 works so as to allow the relative movement of the inner cylinder 4 and the outer cylinder 5 in the axial direction. In the casing 1, the cylindrical member 6 and the sealing member 7 constituting the inner cylinder 4 and the yoke member 35 constituting the outer cylinder 5 are made of a high magnetic permeability material such as pure iron.

The displacement generating section 2 has a disk-shaped permanent magnet 11 provided with its S-pole surface in close contact with the inner surface of a yoke member 35 constituting the outer cylinder 5, and one end of which is an N-pole of the permanent magnet 11. A cylindrical magnetostrictive element 12 closely coupled to the surface and arranged coaxially with the casing 1 and the permanent magnet 11, an S pole face on the upper surface side of the magnetostrictive element 12 in the drawing, and an N pole face on the inner cylinder 4 And a disk-shaped permanent magnet 13 which is closely attached to the inner surface of the sealing member 7.

The magnetic field applying unit 3 includes the above-described permanent magnet 11,
13 and a coil 14 disposed concentrically with the magnetostrictive element 12 around the magnetostrictive element 12. Coil 14
Is wound around the outer periphery of a bobbin 15 formed of a non-magnetic material such as resin or aluminum. A winding frame flange 16a located below the winding frame 15 in the drawing is fixed to an inner surface of the yoke member 35 by a screw (not shown).

In the casing 1, the inner cylinder 4 and the yoke member 35 are formed by the coil 14 and the permanent magnets 11 and 13.
Since the gap 10 also has a function as a closed magnetic circuit, it is desirable that the gap 10 be as narrow as possible from the viewpoint of reducing the magnetic resistance.

The magnetostrictive element 12 is made of Ni as in the first embodiment.
It is formed of a magnetic material having a magnetostrictive property such as a system alloy, an Fe-Al alloy, a ferrite alloy, a rare earth metal-transition metal alloy, or the like.

With the above configuration, the permanent magnet 11
The magnetic flux coming out of the N pole of the magneto-strictive element 12 → the permanent magnet 13 →
Sealing member 7 → cylindrical member 6 → yoke member 35 → permanent magnet 1
One closed magnetic circuit is configured by each of the above elements so as to pass through one path. And the permanent magnet 11,
A permanent magnet 1 is provided in series with a closed magnetic circuit to apply a bias magnetic field to the magnetostrictive element 12.
1 and the magnetic field applied based on the permanent magnet 13 are added to the magnetostrictive element 1.
2 is applied in the axial direction as a bias magnetic field. By the application of the bias magnetic field, the magnetostrictive element 12 is held in a state of being extended by a predetermined amount in the axial direction or contracted by a predetermined amount in the axial direction as compared with a case where no bias magnetic field is applied. Whether the element expands or contracts depends on the characteristics of the material constituting the magnetostrictive element 12, but in the second embodiment, for convenience of explanation, the magnetostrictive element 12 is applied by applying a bias magnetic field as in the first embodiment. The description will be made on the assumption that it is held in a state of being extended by a predetermined amount in the axial direction.

Since the coil 14 is arranged concentrically with the magnetostrictive element 12, the magnetic field generated by the coil 14 increases or decreases the intensity of the magnetic field applied to the magnetostrictive element 12. Therefore, a current in a direction in which the strength of the magnetic field applied to the magnetostrictive element 12 becomes larger than the bias magnetic field level is applied to the coil 14.
, The magnetostrictive element 12 further extends by an amount corresponding to the increase in the applied magnetic field. Conversely, when a current is applied to the coil 14 such that the intensity of the magnetic field applied to the magnetostrictive element 12 is smaller than the bias magnetic field level, the magnetostrictive element 12 contracts by an amount corresponding to the decrease in the applied magnetic field. Therefore, by controlling the current flowing through the coil 14, the magnetostrictive element 12
Can be expanded and contracted. The expansion and contraction displacement of the magnetostrictive element 12 can be taken out as a relative displacement between the inner cylinder 4 and the outer cylinder 5. For example, if the outer cylinder 5 is fixed, the displacement of the inner cylinder 4 can be transmitted to a load (not shown), and the function as an actuator can be exhibited here.

In the case of the second embodiment, the inner cylindrical body 4 and the outer cylindrical body 5
Are connected by the guide members 21 and 22 oriented in the axial direction, respectively, so that the bending movement of the connecting portion 27 of the guide member does not hinder the relative movement of the inner cylinder 4 and the outer cylinder 5 in the axial direction. Since the relative movement between the inner cylinder 4 and the outer cylinder 5 in the direction perpendicular to the axis can be prevented by the tensile rigidity of the connecting portion 27 of the guide member, the gap 10 is narrowed, and the outer periphery of the yoke member 35 and the inner periphery of the cylindrical member 6 are reduced. There is no direct contact. Therefore, unlike the case of using a plain bearing for support, solid friction does not occur and the controllability of the actuator can be improved.

Moreover, in the second embodiment, an external force in a direction perpendicular to the axial direction of the actuator or a moment (twisting force) about an axis perpendicular to the axial direction of the actuator acts on the inner cylindrical body 4 or the outer cylindrical body 5. Guide member 2
The tension between the inner and outer cylinders 4 and 5 prevents the inner and outer cylinders 4 and 5 from coming into contact with each other due to the tensile stiffness of the inner and outer cylinders 5. ,
It is configured such that expansion and contraction of the magnetostrictive element 12 is not hindered. The function of the guide members 21 and 22, that is, the effect of restricting the relative movement in the direction perpendicular to the axis while allowing the relative movement in the axial direction between the inner cylinder 4 and the outer cylinder 5 is shown in FIG.
Since it is larger than the elastic support rings 19 and 20 shown in the first embodiment, it is possible to perform better control.

In the second embodiment shown in FIG. 2, a bias magnetic field is applied to the magnetostrictive element 12 by using the permanent magnets 11 and 13, but the DC current corresponding to the amount of the generated bias magnetic field is applied to the coil 14. , The permanent magnet may be omitted by constantly flowing. Further, the coil 14
Is fixed to the yoke member 35 by a bobbin flange 16a located on the lower side of the bobbin 15 in the drawing, but instead of this, the bobbin flange 16b located above the bobbin 14 in the drawing. It may be fixed to the sealing member 7 of the inner cylinder 4. Third Embodiment FIG. 4 is a sectional view of a magnetostrictive actuator according to a third embodiment of the present invention.

In FIG. 4, the same parts as those in FIG. 1 or 2 are denoted by the same reference numerals. Therefore, a detailed description of the overlapping part will be omitted. The actuator according to the third embodiment is also roughly divided into a cylindrical casing 1, a displacement generator 2 accommodated in the casing 1 coaxially with the casing 1, and a magnetic field for applying a magnetic field to the displacement generator 2. And an application unit 3. The displacement generating unit 2 and the magnetic field applying unit 3 are the same as those in the first embodiment. Particularly, the difference from the first embodiment is the configuration of the guide member used for the casing 1. , 22 are employed in the second embodiment.

Hereinafter, the structure of the casing 1 different from that of the first embodiment will be mainly described. The casing 1 includes an inner cylindrical body 4, an outer cylindrical body 5, and a thin plate-shaped guide member 21 for connecting these members,
22. These guide members 21, 2
2 is the same as FIG. 3 of the second embodiment, and the inner flange portion 25 and the outer flange portion 26 formed in a ring shape as shown in FIG. 5 are geometrically symmetric. And are integrally formed by being connected by four connecting portions 27. The bending function of the connecting portion 27 functions to allow relative movement of the inner cylinder and the outer cylinder in the axial direction.

As for the connection between the guide member 21 and the inner cylindrical body 4, the end of the guide member 21 is attached to the L-shaped notch around the sealing member 7 facing the upper side in the drawing, and the guide member fixing ring is provided. At 28, it is pressed downward in the drawing and fixed with screws (not shown). The coupling between the guide member 21 and the outer cylindrical body 4 is performed by connecting the end of the guide member 21 to the upper surface of the flange portion that protrudes around the upper end side of the cylindrical member 8 in the drawing, and the guide member fixing ring 29 to the lower side in the drawing. The retainer is fixed with screws (not shown).

The connection between the guide member 22 and the inner cylindrical body 4 is carried out by pressing the end of the guide member 22 on the lower end surface of the cylindrical member 6 in the drawing with the guide member fixing ring 30 in the upward direction in the drawing, not shown. It is fixed with screws. Guide member 22
Is connected to the outer cylinder 5 by connecting the end of the guide member 22 to the upper surface in the drawing of the flange portion projecting around the sealing member 9.
The guide member fixing ring 31 is pressed downward in the drawing and is fixed with a screw (not shown). Notches 32 are provided at four locations around the lower surface of the cylindrical member 8 in the drawing.
The central portion of the guide member 22 does not contact the cylindrical member 8.

As shown in FIG. 5, the guide members 21 and 22 have inner flange portions 25 and outer flange portions 2.
6 and the connecting portion 27 are desirably formed integrally. However, as shown in FIGS. 6 and 7, the respective members may be configured as separate bodies. That is, FIG. 7 is a top view mainly showing the guide member 21 arranged at the upper part in FIG.
And the four connecting portions 27 are separately formed, and the connecting portions 27 are radially arranged. In this case, the inner flange portion 25 is also used as the guide member fixing ring 28 and the outer flange portion 25 is used. The part 26 is also used as a function of the guide member fixing ring 29.

That is, the guide member fixing rings 28 and 29 shown in FIG.
And fixed to the sealing member 7 of the inner cylinder 4 with the outer flange 26
And is fixed to the cylindrical member 8 of the outer cylinder 4.

Similarly, the guide member 22 arranged below in FIG. 6 has the inner flange portion 25 and the outer flange portion 26 and the four connecting portions 27 as separate bodies. The portion 25 also has the function of the guide member fixing ring 30 shown in FIG. 4, and the outer flange portion 26 also has the function of the guide member fixing ring 31 shown in FIG. That is, the guide member fixing rings 30 and 31 shown in FIG. 4 are omitted, the connecting portion 27 is fixed to the cylindrical member 8 of the inner cylindrical body 4 by the inner flange portion 25, and is fixed to the sealing member 9 by the outer flange portion 26. I have.

In the actuator having the configuration according to the third embodiment as described above, the permanent magnets 11 and 13 are interposed in series in a closed magnetic circuit and the magnetostrictive element 12 is provided in the same manner as in the first and second embodiments. From the state where the bias magnetic field is applied, the strength of the magnetic field applied to the magnetostrictive element 12 to the coil 14 concentrically arranged with the magnetostrictive element 12 is lower than the bias magnetic field level. When a current having a larger direction is applied, the magnetostrictive element 12 further expands or contracts by an amount corresponding to the increase in the applied magnetic field. vice versa,
When a current is applied to the coil 14 in a direction in which the strength of the magnetic field applied to the magnetostrictive element 12 is smaller than the bias magnetic field level, the magnetostrictive element 12 can contract or expand by an amount corresponding to the decrease in the applied magnetic field. .

Therefore, by controlling the current flowing through the coil 14, the magnetostrictive element 12 is expanded and contracted, and the expansion and contraction displacement of the magnetostrictive element 12 is taken out as relative displacement between the inner cylinder 4 and the outer cylinder 5. Can be.

In the third embodiment as well, the elastic deformation of the elastic support rings 19 and 20 causes the inner cylinder 4 and the outer cylinder 5 to move relative to each other in the axial direction, as in the first embodiment. Since it is supported so that it can move freely, unlike the case where it is supported using a slide bearing, solid friction does not occur and the controllability of the actuator can be improved. Also, in the closed magnetic circuit, since the facing area of the gap 10 between the cylindrical member 6 and the cylindrical member 8 is large, the magnetic resistance of the gap 10 can be reduced without increasing the size compared to the conventional actuator. Thus, the bias magnetic field applied to the magnetostrictive element 12 is made uniform in the axial direction, so that the displacement range with good controllability can be widened and the effect of preventing magnetic leakage to the outside can be obtained.

Further, in addition to the same effects as those of the first embodiment, in the third embodiment, an external force in a direction perpendicular to the axial direction of the actuator or the axial force of the actuator is applied to the inner cylinder 4 or the outer cylinder 5. Even when a moment (twisting force) about an axis perpendicular to the direction is applied, the guide members 21 and 2
2 prevents the inner cylindrical body 4 and the outer cylindrical body 5 from contacting with each other, and at the same time allows the axial movement of the inner cylindrical body 4 and the outer cylindrical body 5 relative to each other by bending deformation of the guide members 21, 22. It is configured so as not to hinder the expansion and contraction of the element. The function of the guide members 21 and 22, that is, the effect of restricting the relative movement in the direction perpendicular to the axis while allowing the relative movement in the axial direction between the inner cylinder 4 and the outer cylinder 5 is the first embodiment of FIG. Since it is larger than the elastic support rings 19 and 20 shown in the example, it is possible to perform better control.

The actuators shown in FIGS. 4 and 6 also have annular grooves 17 and 18 formed on the outer periphery of the inner cylindrical body 4 and have elastic support rings 19 having a circular cross section in these annular grooves 17 and 18. , 20 are mounted. In this case, the elastic support rings 19 and 20 are attached to the inner cylindrical body 4 during assembly.
Relative positioning between the outer cylinder 5 and the inner cylinder 4
It also has a function of matching the axis of the outer cylinder 5 with the axis of the outer cylinder 5.

That is, in the magnetostrictive actuator shown in FIGS. 4 and 6, the elastic support rings 19 and 20 are not provided, and the relative movement between the inner cylinder 4 and the outer cylinder 5 is achieved only by the guide members 21 and 22. Assuming that the inner cylinder 4 and the outer cylinder 5 must be accurately aligned with the center axis via the minute gap 10 during the assembling process, the assembling process may be complicated. Occurs. However, according to the present embodiment in which the elastic support rings 19 and 20 are provided,
At the time of the assembling process, the center axes of the two can be accurately matched only by inserting the inner cylinder 4 into the outer cylinder 5 with the elastic support rings 19 and 20 mounted. (Fourth Embodiment) FIG. 8 is a sectional view of a magnetostrictive actuator according to a fourth embodiment of the present invention.

In FIG. 8, the same parts as those in FIGS. 1 to 7 are shown in the same manner, and the description of the overlapping parts will be omitted. The feature of the fourth embodiment is that the guide member 22 disposed below the guide members 21 and 22 is omitted from the third embodiment.

That is, the structure of the upper half in FIG. 8 corresponds to the actuator of the third embodiment shown in FIG. 4, and the structure of the lower half in FIG. 8 corresponds to the structure of the actuator of the first embodiment shown in FIG. Has become.

As described above, even when the guide member 22 is omitted, and the guide member 21 is supported only, the external force in the direction perpendicular to the actuator axis or the external force perpendicular to the actuator axis can be applied to the inner cylinder 4 or the outer cylinder 5. When a moment (twisting force) around the axis is applied, contact between the inner cylinder 4 and the outer cylinder 5 is prevented by the tensile rigidity of the guide member 21, and at the same time, the outer deformation of the inner cylinder 4 is prevented by bending deformation of the guide member 21. It is possible to allow relative movement in the axial direction with respect to the cylinder 5, and to function so as not to hinder expansion and contraction of the magnetostrictive element. The function of the guide member 21, that is, the effect of restricting the relative movement in the direction perpendicular to the axis while allowing the relative movement in the axial direction between the inner cylinder 4 and the outer cylinder 5 is the same as that in the first embodiment of FIG. Since it is larger than the elastic support rings 19 and 20 shown, it is possible to perform control better than in the first embodiment. (Fifth Embodiment) FIG. 9 is a sectional view showing a magnetostrictive actuator according to a fifth embodiment of the present invention. In this figure, the same parts as those in FIGS. 1 to 7 are indicated by the same reference numerals.
Therefore, a detailed description of the overlapping part will be omitted.

The actuator of the fifth embodiment is also roughly divided into a double-cylindrical casing 1 and a displacement generator 2 accommodated in the casing 1 coaxially with the casing 1.
And a magnetic field applying unit 3 for applying a magnetic field to the displacement generating unit 2. Displacement generating section 2 and magnetic field applying section 3
Are similar to those of the first to fourth embodiments, and the feature of the present embodiment is the structure of the casing 1.

A flange 37 is formed on the outer peripheral surface of the cylindrical member 6 of the inner cylinder 4 constituting the casing 1 so as to project outward. On the other hand, the cylindrical member 8 of the outer cylinder 5
A flange 38 is formed to protrude inward on the inner peripheral surface of the. A compressed elastic ring member 39 is interposed between the flange 37 and the flange 38, and the flange 37 and the flange 38 are arranged to repel each other by the elastic force of the elastic ring member 39. Thereby, the magnetostrictive element 1
2 is given a compressive force.

In the magnetostrictive element 12, when the compressive force is applied in advance in the direction of the expansion and contraction, the amount of expansion and contraction displacement increases, but as shown in FIG. In this case, the amount of expansion and contraction displacement is maximized. Therefore, when the control object C is vertically controlled while being supported in the vertical direction as in the magnetostrictive actuator A shown in FIG. 11, the cross-sectional area of the magnetostrictive element is adjusted so that the surface pressure acting on the magnetostrictive element becomes appropriate. Should be set. In this case, it is effective to appropriately set the thickness of the magnetostrictive element 12 using the actuator shown in the first to fourth embodiments.

However, when the movement of the control target C is to be controlled in the horizontal direction as in the magnetostrictive actuator B shown in FIG. 11, the weight of the control target C does not act in the direction of gravity unlike the actuator A. Therefore, it is desirable to apply a compressive force to the magnetostrictive element. In the fifth embodiment shown in FIG. 9, the elastic ring member 29 is interposed in the gap between the inner cylinder 4 and the outer cylinder 5 constituting the casing 1 in a compressed state. Using this elastic force, an appropriate compressive force can be applied to the magnetostrictive element 12.
Therefore, the configuration is particularly suitable for the case where the movement of the control target is to be controlled in the horizontal direction as in the magnetostrictive actuator B shown in FIG. (Sixth Embodiment) FIG. 12 is a sectional view of a magnetostrictive actuator according to a sixth embodiment of the present invention. In this figure, the same parts as those in FIGS. 1 to 9 are denoted by the same reference numerals. Therefore, a detailed description of the overlapping part will be omitted.

The actuator of the sixth embodiment is also roughly divided into a cylindrical casing 1, a displacement generator 2 accommodated in the casing 1 coaxially with the casing 1, and a magnetic field applied to the displacement generator 2. And a magnetic field applying unit 3 for applying the magnetic field. The displacement generating unit 2 and the magnetic field applying unit 3 are the same as those of the first to fifth embodiments, and the feature is in the structure of the casing 1 like the fifth embodiment.

A flange 37 is formed on the outer peripheral surface of the cylindrical member 6 of the inner cylinder 4 constituting the casing 1 so as to project outward. On the other hand, the cylindrical member 8 of the outer cylinder 5
Is formed to have a shape in which a part of the periphery forms an uneven portion and has a convex portion 38 which is convex on the outer peripheral side, and one inside of the convex portion 38 faces the flange 37. A compressed elastic ring member 39 is interposed between the flange 37 and the convex portion 38, and the elastic ring member 39 is formed between the flange 37 and the convex portion 38.
Repel each other due to the elastic force of Thus, a compressive force is applied to the magnetostrictive element 12 as in the fifth embodiment.

As described above, in the actuator of the sixth embodiment shown in FIG. 12, similarly to the fifth embodiment, the elastic ring member is provided in the gap between the inner cylinder 4 and the outer cylinder 5 constituting the casing 1. 39 is mounted in a compressed state, so that the magnetostrictive element 12 can be used by utilizing this elastic force without increasing the size.
Can be given an appropriate compression force. Therefore, the configuration is particularly suitable for the case where the movement of the control target is to be controlled in the horizontal direction as shown as the magnetostrictive actuator B in FIG.

In the sixth embodiment, as shown in the first embodiment in FIG.
4 and a function as a closed magnetic circuit for the permanent magnets 11 and 13. And the gap 1 between them
0 is desirably as small as possible from the viewpoint of reducing the magnetic resistance. In the actuator of the sixth embodiment, however, the area where the inner cylinder 4 and the outer cylinder 5 face each other with the minute gap 10 therebetween is the fifth. The configuration is significantly wider than that of the embodiment.

As described above, since the opposed area between the cylindrical member 6 and the cylindrical member 8 is large, the magnetic resistance of the gap can be reduced without increasing the size. As a result, the bias magnetic field applied to the magnetostrictive element 12 can be made uniform in the axial direction to widen the range of displacement with good controllability, and also prevent magnetic leakage to the outside.

[0077]

As described above, according to the present invention, even when an external force is applied to the magnetostrictive actuator in a direction perpendicular to the expansion / contraction axis, damage to the magnetostriction element is prevented and the expansion and contraction of the magnetostriction element is caused. The response performance can be maintained without the solid friction of the support portion.

[Brief description of the drawings]

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

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

FIG. 3 is a top view of a guide member in a magnetostrictive actuator according to a second embodiment of the present invention.

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

FIG. 5 is a top view of a guide member in a magnetostrictive actuator according to a third embodiment of the present invention.

FIG. 6 is a sectional view of a magnetostrictive actuator according to a modification of the third embodiment of the present invention.

FIG. 7 is a top view of a guide member in a magnetostrictive actuator according to a modification of the third embodiment of the present invention.

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

FIG. 9 is a sectional view of a magnetostrictive actuator according to a fifth embodiment of the present invention.

FIG. 10 is a diagram showing the relationship between the surface pressure and the amount of expansion and contraction in a magnetostrictive element.

FIG. 11 is a diagram showing a usage example of the magnetostrictive actuator according to the present invention.

FIG. 12 is a sectional view of a magnetostrictive actuator according to a sixth embodiment of the present invention.

FIG. 13 is a sectional view of a conventional magnetostrictive actuator.

FIG. 14 is a diagram showing a relationship between a magnetic field and distortion of a magnetostrictive element.

FIG. 15 is a diagram showing a relationship between a control magnetic field of a magnetostrictive element to which a bias magnetic field is applied and distortion.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 casing 2 displacement generating section 3 magnetic field applying section 4 inner cylinder 5 outer cylinder 6 cylindrical member 7 sealing member 8 cylindrical member 9 sealing member 10 gap 11 permanent magnet 12 magnetostrictive element 13 permanent magnet 14 coil 15 winding frame 19 elastic support ring Reference Signs List 20 elastic support ring 21 guide member 22 guide member

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H02N 2/00 G05D 3/00 H01L 41/12

Claims (10)

(57) [Claims] A displacement generating means made of a magnetic material having magnetostriction; a magnetic field generating means disposed around the displacement generating means for applying a magnetic field to the displacement generating means; A magnetostrictive actuator comprising a magnetic field generating means and a closed magnetic circuit component constituting a closed magnetic circuit together with the displacement generating means, wherein the closed magnetic circuit component is a bottomed inner cylindrical member; A bottomed outer cylinder member disposed concentrically with an outer periphery of the inner cylinder member and a gap therebetween, and a bottom inner surface side of the inner cylinder member and a bottom inner surface side of the outer cylinder member, respectively. A magnetostrictive actuator, wherein one end and the other end of the displacement generating means are connected to each other. 2. A guide means is provided in a gap between the outer periphery of the inner cylinder member and the inner periphery of the outer cylinder member to allow relative movement between the inner cylinder member and the outer cylinder member by elastic deformation. 2. The magnetostrictive actuator according to claim 1, wherein: 3. A thin plate member, one end of which is attached to the inner cylinder member and the other end of which is attached to the outer cylinder member, the plane of which is disposed in a direction substantially orthogonal to the direction of displacement of the displacement generating means. The magnetostrictive actuator according to claim 1, wherein: 4. A displacement is allowed in a displacement direction of the displacement generating means in a gap between an outer periphery of the inner cylinder member and an inner periphery of the outer cylinder member, and the displacement is restricted in a direction other than the displacement direction. 2. The magnetostrictive actuator according to claim 1, further comprising a guide for generating a restraining force. 5. The displacement generating means, wherein the thin plate member connects an inner ring member attached to the inner cylinder member, an outer ring member attached to the outer cylinder member, and connects the inner ring member and the outer ring member. The magnetostrictive actuator according to claim 1, comprising a plurality of connecting members that can be deformed by (1). 6. A displacement generating means comprising a magnetic material having a magnetostriction, a magnetic field generating means disposed around the displacement generating means and for applying a magnetic field to the displacement generating means; A bottomed cylindrical first member accommodating a magnetic field generating means, a second member for forming a closed magnetic circuit together with the first member and the displacement generating means, and one end attached to the first member; A thin plate member having the other end attached to the second member and having a plane disposed in a direction substantially orthogonal to the displacement direction of the displacement generating means; one end of the displacement generating means being a first member; The other end is second
The first member is connected to a first member by elastic deformation of the thin plate member.
A magnetostrictive actuator, wherein the member and the second member are configured to be relatively movable. 7. The second member comprises a bottomed cylindrical member,
7. The magnetostrictive actuator according to claim 6, wherein the cylindrical portions of the first member and the second member are concentrically opposed to each other with a minute gap therebetween. 8. The thin plate member connects a first ring member attached to the first member, a second ring member attached to the second member, and connects the first ring member and the second ring member. 7. The magnetostrictive actuator according to claim 6, comprising a plurality of connecting members deformable by said displacement generating means. 9. A displacement generating means comprising a magnetic material having magnetostriction, a magnetic field generating means disposed around the displacement generating means and for applying a magnetic field to the displacement generating means; A magnetostrictive actuator comprising a magnetic field generating means and a closed magnetic circuit component constituting a closed magnetic circuit together with the displacement generating means, wherein the closed magnetic circuit component is a bottomed inner cylindrical member; A bottomed outer cylinder member disposed concentrically with an outer periphery of the inner cylinder member and a gap therebetween, and a bottom inner surface side of the inner cylinder member and a bottom inner surface side of the outer cylinder member, respectively. An end face on one end side and the other end side of the displacement generating means are connected to each other, and a pressurizing member is provided between the inner cylindrical member and the outer cylindrical member for applying a pressurization in a direction for contracting the displacement generating means. Magnetostrictive a Cuctuator. 10. The magnetostrictive actuator according to claim 9, wherein said actuator is arranged along a vertical direction.