ELECTROSTRICTION ACTUATOR AND ELECTROSTRICTION TYPE HYDRAULIC CONTROL VALVE

摘要

PURPOSE:To prevent the operation characteristics from being varied in accordance with the variation of temperature, by accommodating an electrostriction type actuator element into a cylinder which is made of a material having the equal thermal expansion coefficient to that of the actuator element and has the equal length. CONSTITUTION:An actuator element 4 constituted of a pillar-shaped ceramic having an electrostriction effect is accommodated into a ceramic cylinder 8 which is made of the equal material to the actuator element 4 or a material having the equal linear expansion rate and longitudinal elastic coefficient and has the equal length to the actuator element 4, and the edge surfaces of the element 4 and the cylinder 8 are supported in common by a supporting piston 7. Therefore, even if temperature considerably varies, each length of the actuator element 4 and the ceramic cylinder 8 becomes equal, so the operation characteristics of the electrostriction type actuator are not affected by the temperature.