Valve mechanism for high pressure tank and valve device for high pressure tank

A valve mechanism comprising:

• a first plunger provided in a flow passage and having a thread around an axis of the first plunger, the thread engaging with a threaded portion provided on an inner wall of the flow passage, the first plunger being movable along the axis by rotating around the axis;
• a second plunger provided in the flow passage and having a first end and a second end opposite to the first end along the axis, the first end engaging with the first plunger such that the first plunger is relatively rotatable with respect to the second plunger and the second plunger is movable along the axis by rotating the first plunger;
• a seal member provided to surround the second plunger around the axis so as to contact a circumferential outer surface of the second plunger;
• and
• a valve element provided in the flow passage and having a forward end and a back end opposite to the forward end along the axis, the back end engaging with the second end of the second plunger such that the valve element is movable along the axis according to movement of the second plunger so as to be seated on and separated from a valve seat which is provided in the flow passage.