Method for manufacturing actuator

Abstract

A method for manufacturing an actuator includes: creating a semi-cured product in a semi-cure state in such a manner that an element material that is to be a string-shaped actuator element of all actuator that is made of dielectric elastomer and includes the actuator element is formed in a string shape and that the element material is heated to its cure temperature or higher at least one of in and after formation; and creating a fully-cured product with a cure reaction of the semi-cured product completed in such a manner that the semi-cured product is heated while elongated in its axial direction.

1 . A method for manufacturing an actuator, comprising:
 creating a semi-cured product in a semi-cure state in such a manner that an element material to be a string-shaped actuator element of an actuator that is made of dielectric elastomer and includes the actuator element is formed in a string shape and that the element material is heated to a cure temperature thereof or higher at least one of in and after formation; and   creating a fully-cured product with a cure reaction of the semi-cured product completed in such a manner that the semi-cured product is heated while elongated in an axial direction thereof.   
   
   
       2 . The method for manufacturing an actuator according to  claim 1 , wherein the element material is formed in a string shape by extrusion in the process of creating a semi-cured product. 
   
   
       3 . The method for manufacturing an actuator according to  claim 2 , wherein the process of creating a semi-cured product includes forming and heating to create the semi-cured product by heating the element material to the cure temperature thereof or higher while forming the element material in a string shape by extrusion. 
   
   
       4 . The method for manufacturing an actuator according to  claim 2 , wherein the process of creating a semi-cured product includes extrusion-forming the element material in a string shape to create a formed product, and heating the formed product thus extrusion-formed to a cure temperature thereof or higher to create the semi-cured product in the semi-cure state. 
   
   
       5 . The method for manufacturing an actuator according to  claim 4 , wherein the actuator is formed of a number n (n≧1) of layers of actuator elements and the number n of electrode layers made of conductive elastomer that are alternately laminated in a radial direction of the actuator, and has a conductive fluid electrode in a liquid or gel form inside the actuator element that is an innermost layer,
 the extrusion-forming process includes forming by hollow extrusion to create the formed product having a hollow axial part and a multilayer structure in such a manner that the number n of element materials and the number n of electrode materials that are to be the respective electrode layers are formed by multilayer extrusion, and   the method further comprises injecting the fluid electrode into the axial part of the formed product between the process of forming by hollow extrusion and the heating process.   
   
   
       6 . The method for manufacturing an actuator according to  claim 2 , wherein the actuator is formed of a number n (n≧1) of layers of actuator elements and a number n+1 of electrode layers made of conductive elastomer that are alternately laminated in a radial direction of the actuator, and the process of creating a semi-cured product includes creating the semi-cured product having a multilayer structure in such a manner that the number n of element materials and the number n+1 of electrode materials that are to be the respective electrode layers are formed by multilayer extrusion and that the element materials and the electrode materials are heated to cure temperatures thereof or higher at least one of in and after formation. 
   
   
       7 . The method for manufacturing an actuator according to  claim 6 , wherein one of the electrode layers that is the innermost layer is a solid bar electrode having a bar shape. 
   
   
       8 . The method for manufacturing an actuator according to  claim 6 , wherein the actuator has a core rod made of dielectric elastomer inside one of the electrode layers that is the innermost layer, and
 the process of creating the semi-cured product having a multilayer structure includes creating the solid semi-cured product having a multilayer structure in such a manner that the number n of the element materials, the number n+1 of the electrode materials that are to be the respective electrode layers and a core rod material that is to be the core rod are formed by multilayer extrusion and that the element materials, the electrode materials and the core rod material are heated to cure temperatures thereof or higher in or after, or in and after formation.   
   
   
       9 . The method for manufacturing an actuator according to  claim 1 , wherein a modulus of elasticity of the semi-cured product in the semi-cure state is improved by a percentage ranging from 20% to 60%, inclusive, in comparison with that of an uncured product when a difference between the modulus of elasticity of the fully-cured product and that of the uncured product in an uncure state prior to beginning of cure is deemed 100%. 
   
   
       10 . The method for manufacturing an actuator according to  claim 1 , wherein the actuator has an electrode layer disposed on a surface of the actuator element, and
 the method further comprises applying an electrode material that is to be the electrode layer on a surface of the fully-cured product after the process of creating a fully-cured product.   
   
   
       11 . The method for manufacturing an actuator according to  claim 1 , wherein the semi-cured product is elongated at an elongation rate of 45% or higher in the process of creating a fully-cured product. 
   
   
       12 . The method for manufacturing an actuator according to  claim 2 , wherein the fully-cured product has a radial thickness in a range from 0.02 mm to 0.50 mm, inclusive, and an external diameter in a range from 0.1 mm to 2.0 mm, inclusive.