Abstract: The present invention comprises: a piston provided in a cylinder hole; a lid member which closes an opening on the other side of the cylinder hole; and elastic members and which are provided between the piston and the lid member. The elastic members and comprise a first elastic member provided on the piston side of the cylinder hole, and a second elastic member provided on the lid member side of the cylinder hole. The second elastic member has a base portion provided in line with the first elastic member, and a protruding portion protruding from the piston side end surface of the base portion. When the piston has moved in the axial direction to the lid member side, the protruding portion touches the piston, undergoing compressive deformation, and the base portion subsequently undergoes compressive deformation.

Abstract: The present invention comprises: a piston provided in a cylinder hole; a lid member which closes an opening on the other side of the cylinder hole; and elastic members and which are provided between the piston and the lid member. The elastic members and comprise a first elastic member provided on the piston side of the cylinder hole, and a second elastic member provided on the lid member side of the cylinder hole. The second elastic member has a base portion provided in line with the first elastic member, and a protruding portion protruding from the piston 22-side end surface of the base portion. When the piston has moved in the axial direction to the lid member 23-side, the protruding portion touches the piston, undergoing compressive deformation, and the base portion subsequently undergoes compressive deformation.