A valve driving device includes a plurality of valve bodies that are simultaneously
driven. Driven gears are disposed symmetrically with respect to an axis of the
a common gear. Rubber valve bodies which are separate from the driven gears are
disposed on the lower surfaces of the driven gears. The valve bodies are slidably
aligned with a valve seat which is formed by smoothly denting a valve seat plate.
The driven gears are brought into contact with the valve seat under pressure by
one leaf spring member to open or close communication holes (valve openings) thereby
interrupting or opening a flow-path from an inflow hole.
