JPH05130786A - Strain actuator - Google Patents

Abstract

PURPOSE:To provide a strain actuator having a structure in which a stress generated at a contactor or a knob is alleviated without necessity of a machining accuracy. CONSTITUTION:Contact surfaces of contactors 12, 10 in contact with a reference base 6 or/and a knob 8 are formed in spherical convex surfaces 12a, 10a. Or, the base 6 or/and the knob 8 is formed with spherical concave surfaces 6a, 8b (or spherical convex surfaces) to be engaged with the surfaces 12a, 10a (or spherical concave surfaces). Or, the surfaces 12b, 10b are formed on the opposed surfaces of the contactors 12, 10 and the base 6 or/and the knob 8, and spheres 21, 20 are engaged therein. A sphere in which the knob 8 is slidably inserted is provided, and rotatably engaged with a spherical recess surface formed on a knob holding plate 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a strain actuator that moves various actuated bodies by expanding and contracting a strain element such as a magnetostrictive material, an electrostrictive material, a piezoelectric material, and a photostrictive material. The present invention relates to a contact structure of a contactor that transmits a reference to a reference stand or a knob.

[0002]

Prior Art and Problems to be Solved by the Invention FIG.
(A) and (B) are respectively a plan view and a longitudinal sectional view showing a conventional strain actuator, and a holder 30 for accommodating the magnetostrictive element 1 has a reference table 6 and a knob at the lower end and the upper end of the case 4 in the drawing. The holding plate 5 is applied, the connecting bolt 7 is inserted from the knob holding plate 5, screwed into the screw hole of the reference base 6, and tightened. Note that instead of the case 4, a plurality of connecting rods may be interposed between the reference base 6 and the knob holding plate 5 and screwed. The magnetostrictive element 1 has a rod shape, and the magnetostrictive element 1 is put in the tubular portion of the bobbin 3 having the winding 2. The lower end of the magnetostrictive element 1 is supported on the reference table 6 via a contactor 12 fitted to the bobbin 3 at the lower end tube portion. The knob 8 is vertically movably inserted through the center of the knob holding plate 5, and is fitted between the flange 8a provided at the lower portion of the knob 8 and the upper end of the magnetostrictive element 1 in the tubular portion of the bobbin 3 and the upper surface thereof. Contact 1 having a flat surface (contact surface with the lower surface of the knob 8)
0 is inserted. Further, a compression spring 9 is interposed between the flange 8a of the knob 8 and the knob holding plate 5, and a compression spring 11 serving as a bobbin pressing member is interposed between the knob holding plate 5 and the bobbin 3. The contacts 10, 1
2, the knob 8, the knob holding plate 5, the case 4, and the reference table 6 are made of a magnetic material, and these components and the magnetostrictive element 1 form a closed magnetic circuit.

In such a conventional strain actuator, when the winding 2 is energized, the magnetostrictive element 1 is generated by the generated magnetic field.
Extends and pushes out the knob 8, but if the knob 8 is attached so as to be inclined or the bobbin 3 is inclined with respect to the reference table 6, the contact between the contact 12 and the reference table 6 or the contact 10 The contact between the knob and the flange 8a of the knob 8 becomes a point contact or a line contact, which may lead to damage of these parts due to stress concentration. Therefore, the parallelism of the surfaces of these contact portions and the reference base 6 of the magnetostrictive element 1 may occur. It is necessary to accurately measure the verticality of the knob 8 and the contact surface, which requires processing accuracy,
There is a problem in that it takes a lot of time and effort to manufacture and the manufacturing cost becomes high.

In view of this problem, it is an object of the present invention to provide a strain actuator having a structure in which the stress generated in the contactor, the knob, etc. is relieved without requiring much processing accuracy.

[0005]

In the strain actuator of the present invention, the contact surface of the contactor which comes into contact with the reference table or the knob is formed into a spherical convex surface, or the spherical surface (or spherical surface) is formed on the reference table or the knob. It is formed into a spherical concave surface (or spherical convex surface) that fits into the concave surface, or a spherical concave surface is formed on each of the facing surfaces of the contactor and the reference base or the knob, and the spherical body is fitted therein. Further, according to the present invention, a spherical body in which the knob is slidably inserted is provided, and the spherical body is rotatably fitted to a spherical concave surface provided on the knob holding plate.

[0006]

The strain actuator of the present invention has the above structure, and since the contactor is a spherical surface and contacts the reference stand or the knob,
Stress concentration is relieved. Also, the sphere that penetrates the knob,
By fitting the spherical concave surface provided on the knob holding plate, the inclination of the knob is allowed and stress concentration is alleviated.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1A is a longitudinal sectional view showing an embodiment of a strain actuator according to the present invention, a plan view of which is similar to FIG. 3A showing a conventional example. Three
The same symbols as are provided to perform the same function. In the present embodiment, the contact surfaces of the upper and lower contacts 10 and 12 of the magnetostrictive element 1 with respect to the knob 8 or the reference table 6 are formed into spherical convex surfaces 10a and 12a.

With such a structure, even if the reference base 6 and the knob 8 are slightly inclined with respect to the magnetostrictive element 1, the contact surface is a spherical surface and a flat surface. Inclination of the children 10 and 12 is allowed, stress concentration does not occur,
Prevents damage due to stress concentration.

FIG. 1B shows another embodiment of the present invention.
A spherical concave surface 8b that fits into the spherical convex surface 10a is formed on the lower surface of the knob 8, that is, the surface that contacts the contact 10, and the contact surface of the reference table 6 with the contact 12 as well as the spherical convex surface 12a of the contact 12 is formed. The spherical concave surface 6a to be fitted is formed.

With such a structure, as compared with the case of FIG. 1A, the contact area of the contact surfaces of the contacts 10 and 12 with the knob 8 or the reference table 6 becomes wider, and the stress concentration relaxing effect is further increased. And the bobbin 3 and the magnetostrictive element 1 are stably supported.

FIG. 1C shows another embodiment of the present invention.
Spherical concave surfaces 10b, 8c and 12b, 6b are provided on both the facing surfaces of the contact 10 and the knob 8 and the facing surface of the contact 12 and the reference base 6, respectively, and spherical bodies 20, 21 are provided on these spherical concave surfaces, respectively. Is. According to this embodiment,
Since the contacts 10, 12 and the knob 8 or the reference table 6 can be machined by spherical concave surfaces having the same inner diameter, the machining is easy.

FIG. 1 (D) is obtained by reversing the concavo-convex relationship in FIG. 1 (B), in which the contact 10 has a spherical concave surface 10c and the knob 8 has a spherical convex surface 8d fitted therein. This structure can also be adopted in the contactor 12, and the same effect as in FIG. 1 (B) can be exhibited.

In the above embodiment, both contacts 10, 12 are
Regarding the above, an example in which the same contact portion structure is adopted is shown, but even when the contact portion structure is adopted for only one of the contacts, a stress relaxation effect superior to the conventional one can be obtained. Moreover, you may combine the contact part structure shown in each example.

FIG. 2A shows another embodiment of the present invention,
A knob 13 is slidably inserted into the spherical body 13, and the spherical body 13 is rotatably fitted into the spherical concave surface 22 provided on the knob holding plate 5, and is screwed to the lower surface of the knob holding plate 5. The spherical body 13 is held by the ring-shaped pressing plate 14.

According to this embodiment, since the knob 8 can be tilted to some extent, even if the contact surface between the contact 10 and the knob 8 or the reference base 6 of the contact 12 is not accurately formed, the knob 8 By slightly inclining 8, it is possible to combine them with their contact surfaces in full contact,
High precision is not required for processing the contact surface, and stress concentration is relieved.

FIG. 2B shows the structure of FIG. 2A, which employs the structure of FIG. 1B for the contact portion between the contact 12 and the reference base 6, and the upper contact 10. The upper end portion 10d is fitted into and combined with a hole 8e provided in the knob 8.
According to this embodiment, the knob 8 is different from the case of FIG.
The vertical setting of the magnetostrictive element 1 is easy, and the stress concentration relaxing effect can be obtained.

In the present invention, an electrostrictive material, a piezoelectric material, or a photostrictive material can be used as the strain material instead of the magnetostrictive material, but a rare earth metal-iron system such as Tb having a large electromechanical coupling coefficient is used.
_If a giant magnetostrictive material having a composition such as _0.3 Dy _0.7 Fe _1.95 is used, a large operation amount can be obtained with a small size. In this case, it is very effective in compensating for the fragility of the material.

[0018]

According to the first aspect of the present invention, the stress concentration on the contact surface between the contact and the reference base or the knob is reduced, and the stress concentration on the contact, the knob and the strain element is reduced. Further, since the processing on the contact surface does not require high precision, the processing becomes easy.

According to the second aspect, the stress concentration relaxing effect is further enhanced.

According to the third aspect, the contact, the knob, and the spherical concave surface provided on the reference base may be commonly formed, which facilitates the processing.

According to the fourth aspect, the contactor and the knob or the reference table can be combined in a state of being in contact with each other over the entire surface, and the stress concentration relaxing effect can be obtained, as well as the contact structure similar to the conventional one. It can be adopted and can be manufactured without requiring machining accuracy.

According to the fifth aspect, vertical setting of the strain element and the knob becomes easy.

[Brief description of drawings]

1A to 1C are vertical cross-sectional views showing respective embodiments of a strain actuator according to the present invention.

2A and 2B are vertical cross-sectional views showing other embodiments of the strain actuator according to the present invention.

3A and 3B are a plan view and a vertical sectional view of a conventional strain actuator, respectively.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magnetostrictive element 2 Winding 3 Bobbin 4 Case 5 Knob holding plate 6 Reference stand 7 Coupling screw 8 Knobs 8b, 8c Spherical concave surface 9, 11 Compression spring 10, 12 Contactor 10a Spherical convex surface 10b Spherical concave surface 13 Sphere 20, 21 Sphere 22 Spherical concave surface 30 Holder

Claims (5)

[Claims] 1. A holder for accommodating a strain element has a reference stand at one end, and a knob holding plate at the other end of which a knob is slidably inserted, and both ends of the strain element are respectively provided with contacts. In the strain actuator in contact with the reference table and the knob, the contact surface of the contactor contacting the reference table and / or the knob is formed into a spherical convex surface. 2. A spherical convex surface (or a spherical concave surface) is formed on at least one of the both contact elements according to claim 1,
A strain actuator, wherein a spherical concave surface (or spherical convex surface) that fits into the spherical convex surface (or spherical concave surface) is formed on the knob or the reference base. 3. The spherical concave surface provided on both of the facing surface of the contactor and the reference base or the knob, instead of at least one of the spherical convex surface or the spherical uneven surface constituting the contact portion. And a spherical body fitted to these spherical concave surfaces. 4. A holder for accommodating a strain element has a reference stand at one end and an end plate having a knob attached at the other end, and both ends of the strain element are connected to the reference stand and the knob via contacts, respectively. In the strain actuator which is in contact with or joined to the strain actuator, a spherical body in which the knob is slidably inserted is provided, and the spherical body is rotatably fitted into a spherical concave surface provided in the end plate. .. 5. A strain actuator according to claim 4, wherein the contact structure according to any one of claims 1 to 3 is provided between the reference base and the contact.