Abstract: In the interior of the housing of an accumulator, a metallic bellows and a self-seal mechanism are arranged. The metallic bellows partitions the interior of the housing into a gas chamber and a liquid chamber. The self-seal mechanism includes an elastic seal member and a face which the elastic seal member opposes. When the bellows is compressed to the predetermined extent due to introduction of a compressed gas into the gas chamber, the elastic seal member is brought into contact with the face, thus closing a flow port. The elastic seal member has a slanted face, so that a wedge-shaped liquid guide gap is produced when the elastic seal member is in contact with the face. When, in this condition, the compressed liquid is introduced into the flow port, part of the liquid enters the liquid guide gap, thus permitting the seal member to easily separate from the face.

Abstract: A rod is inserted in a first cylinder. A first oil chamber is defined by the inner surface of the first cylinder. The rod can be reciprocated with a first stroke. A second cylinder is coupled to the first cylinder by a connecting member. A metal bellows is housed in the second cylinder. A gas chamber is defined by the inner surface of the bellows. A second oil chamber is defined by the outer surface of the bellows and the inner surface of the second cylinder. The bellows contracts with a second stroke corresponding to the first stroke of the rod. The first and second oil chambers communicate with each other via an oil path formed in the connecting member. A valve seat is arranged on an end wall of the second cylinder. A valve body is fixed to the bellows so as to oppose the valve seat. If the bellows expands farther than the second stroke when a gas is supplied into the gas chamber, the valve body is brought into contact with the valve seat.