Linear motor-actuated flow control valve

Abstract

A linear motor-actuated flow control valve includes: a casing having an inlet port and an outlet port; a moving-coil linear motor disposed within said casing, said linear motor including a hollow, ferromagnetic core which delimits the interior of said casing into valve chambers and which has a valve hole or holes for communicating said inlet and outlet ports with each other, a bobbin slidably disposed on said core for controlling the opening degree of the valve hole(s), an electromagnetic coil wound on said bobbin, a permanent magnet so arranged that the magnetic flux produced thereby extends axially of said electromagnetic coil, and a magnetic body for forming a magnetic circuit, in cooperation with said core, for the flux produced by said permanent magnet; and spring for biasing said bobbin so that said bobbin is retained at a predetermined position by said spring means when said electromagnetic coil is in the de-energized state, whereby said valve hole(s) is/are held open or closed to a predetermined degree, said spring serving as power supply lines for said electromagnetic coil, wherein the improvement comprises some of said valve holes, referred to a first valve hole(s), disposed at a position lying within said magnetic circuit along the length of said hollow ferromagnetic core, and a second valve hole(s) disposed at the other position(s) lying outside of said magnetic circuit along the length of said core.