PURPOSE: To decrease a minimum expansion length, to reduce a distance between plates, and to improve discharge capacity of fluid by providing the weld part of a bellows plate part so that adjoining weld positions are differed from each other, in a fluid forced feed device welded in a bellows-form manner and having a bellows sheet part.
CONSTITUTION: In a bellows type fluid forced feed device, an eccentric shaft part 13 is eccentrically rotated through drive rotation of a pulley 12, a bellows 4 is expanded and contracted through vertical movement of a moving support 6 through a roller 20 and a rod 8, and fluid sucked through a suction valve 22 through expansion and contraction of the bellows is discharged as a delivery valve 23 is forcibly opened. In this case, the bellows 4 is formed such that a weld part is formed so that adjoining weld positions are differed from each other. Namely, weld balls 40 are formed so that weld parts are alternately changed and the weld balls 40 are prevented from collision with each other. This constitution shortens a minimum expansion length, reduces a distance between plates, and improves discharge capacity (volume efficiency) of fluid.
KUBO HIROSHI
MATSUZAKA MASANORI
