Arc extinguishing chamber, vacuum circuit breaker, and method of assembling arc extinguishing chamber

An arc extinguishing chamber comprising:

• a vacuum interrupter including:
• a movable contact point and a stationary contact point;
• a movable lead electrically connected to the movable contact point;
• a stationary lead electrically connected to the stationary contact point;
• a vacuum container accommodating the movable contact point, the stationary contact point, and the stationary lead and from one end of which the movable lead protrudes outward;
• and
• a bellows connecting the vacuum container and the movable lead to each other, the bellows configured to extend in a closed state in which the movable contact point and the stationary contact point are in contact with each other, and configured to contract in an open state in which the movable contact point and the stationary contact point are separated from each other;
• a contact case having a tubular shape and made of a conductive material;
• a contact fixed to an end of the movable lead, disposed inside a tube of the contact case, and electrically connecting the contact case and the movable lead to each other;
• a seal rod connected to the movable lead and configured to move the movable lead;
• and
• a movable-side support having a cylinder shape with a bottom surface in which a hole through which the seal rod passes is formed, wherein
• an air pressure inside a closed space surrounded and sealed by the bellows, the contact case, and the movable-side support, so as not to cause inflow and outflow of a gas accompanying extension and contraction of the bellows, is atmospheric pressure in the open state, and is less than atmospheric pressure in the closed state.