| 摘要 |
PURPOSE:To prevent sink marks at the time of molding an actuator by providing an inner fitting screw lower than an internal position corresponding to the lower end of a working screw provided outside. CONSTITUTION:A fitting screw 5A is provided outside an upper part of a container 4 containing liquid, and an inner fitting screw 5B to be engaged with the fitting screw 5A is formed inside an actuator 2. An outer working screw 3B to be engaged with an inner working screw 3a inside a top 7 is formed outside the actuator 2. The fitting screw 5B inside the actuator 2 is provided at a lower part than an internal position corresponding to the lower end of the outer working screw 3B. By forming the fitting screw 5B and the working screw 3B in such a relation, thickness on a cylindrical part of the actuator 2 can be almost constant. Thus, nonuniform contraction at the time of cooling after completion of molding can be prevented, thereby preventing the occurrence of sink make. |
