Gas spring device, and balancer device and actuator which use gas spring device

A gas spring device comprising:

• a gas spring that is fixed to a frame, and generates a force proportional to a differential pressure between a pressure in an inner space and an atmospheric pressure;
• a suction/discharge part that is arranged in the gas spring, and is capable of adjusting an amount of gas in the inner space of the gas spring;
• a rotary body that is rotatably arranged in the frame and connected to the gas spring, to which a torque due to the force generated by the gas spring is applied;
• a displacement part that is connected to the rotary body, and is displaced in conjunction with a rotary movement of the rotary body;
• a speed change part that is arranged in the frame, and configured to perform one or both of conversion between a torque applied to the rotary body due to a generating force of the gas spring and a force applied to the displacement part by being arranged between the rotary body and the displacement part, and conversion between a generating force of the gas spring and a torque applied to the rotary body by being arranged between the gas spring and the rotary body;
• and
• a torque compensating part that is arranged in the frame and connected to the rotary body, and sets the torque applied to the rotary body to substantially 0 when the amount of the gas in the inner space of the gas spring is at a predetermined value.