Electrically actuated EGR valve

Claim 1

A valve comprising: a valve seat, positioned about a passage; a rigid valve stem that is movable in a substantially axial manner relative to the valve seat, from a first position corresponding to valve seat closure, to a second position corresponding to non-closure of the valve seat; closure means carried by the valve stem for seating upon the valve seat and for opening and closing the passage; an eccentric that can execute arcuate motion about an axis and comprises, in spaced relation to said axis, a pivotal connection to said stem; a valve stem guide that is spaced from said valve seat and from the pivotal connection of said eccentric to said stem; said valve stem guide comprising a convex wall defining a valve stem passage through which said valve stem extends and which is substantially coaxial with said first-mentioned passage, said convex wall providing a constraint on said valve stem passage as the stem is being axially displaced through the valve stem passage; said eccentric and said convex wall being organized and arranged in relation to said stem such that in response to arcuate motion of said eccentric about said axis from a first angular orientation, corresponding to said first position, to a second angular orientation, corresponding to said second position, the shaft is displaced substantially axially while pivoting with respect to both the eccentric and the valve stem passage, and for a given amount of motion of said eccentric about said axis from said first angular orientation, the closure means is moved relative to the valve seat a smaller distance than the closure means is moved relative to the valve seat for the same given amount of motion of said eccentric about said axis from said second angular orientation.