Patent ID: 11203892

Abstract:
An extensible or contractible driving device that reduces failure caused by water intrusion. A motor (13) is provided in an outer cylinder (7). An inner cylinder (9) is provided on an inner side of the outer cylinder (7), a tip of the inner cylinder has a closing structure, and the inner cylinder relatively moves in an axial direction with respect to the outer cylinder (7). A screw (11) is rotationally driven by a driving force of the motor (13). A guide nut (15) is driven by the screw (11) and moved in a rotation axis direction of the screw (11). A coil spring (17) is disposed on an outer periphery of the screw (11), comes into contact with a tip of the inner cylinder (9), and applies force to the guide nut (15). The screw (11), the guide nut, and the coil spring (17) are housed in an inner space (25) formed by the outer cylinder (7) and the inner cylinder (9). A fluid intake/outlet port (29) is provided at the tip of the inner cylinder (9).