Patent ID: 7628175

Claim:
A metallic bellows-type accumulator comprising: a shell having an attachment portion formed at one end to attach to a given system and having a gas plug fixed at another end to close a gas filling port for filling high pressure gas; a metal bellows capable of extending and contracting and disposed within the shell, one end of the metal bellows being fixedly secured to the shell at the side of the attachment portion and another end of the metal bellows being joined to a bellows cap, so that an inside of the shell is partitioned into an outer gas chamber, in which high pressure gas is enclosed, at a side of the gas plug and an inner liquid chamber, to and from which pressurized liquid is introduced and discharged, said metal bellows having crest portions at an outer diameter side and root portions at an inner diameter side, each of the crest and root portions and having a sectional shape in an axial direction of a U-shape; and an oil port disposed within the liquid chamber to restrict a degree of contraction of the metal bellows; wherein said metal bellows is configured such that, when pressure in the liquid chamber is further reduced after the bellows cap is brought into contact with the oil port, contact surfaces are formed on the metal bellows and a curvature radius of the crest portions at the outer diameter side is reduced from the U-shape to form hair-pin shaped sections, and a curvature radius of the root portions at the inner diameter side is enlarged from the U-shape; wherein the hair-pin shaped sections include the contact surfaces which are formed between the crest portions at the outer diameter side and the root portions at the inner diameter side, and the crest portions at the outer diameter side which are spaced apart from each other.