Solenoid valve

Claim 1

A solenoid valve comprising a mounting base having a first axial bore, an upper piece having a second axial bore and supported on the base concentrically relative to the base by means of a tubular supporting piece and held in position by means of a cover, a coil surrounding at least an axial portion of the upper piece, and a first insert and a second insert which are mounted respectively in the first axial bore and the second axial bore and which form stops for axially opposite ends, forming valve means, of a plunger structure stressed elastically and having a fluid through-passage, at least the first insert having an inner fluid passage opening into a valve seat which can be closed off by the adjacent valve means of the plunger structure, characterized in that the mounting base comprises an inner cylindrical part forming a pole piece projecting axially into the coil toward the upper piece and formed with a third bore coaxial relative to the first axial bore and second axial bore, the plunger structure comprising a cylindrical core sliding in the second axial bore and interacting in engagement contact with a tubular exension piece made of nonmagnetic material which has an inner passage and which slides in the third bore, the core comprising at least one axial passage communicating permanently with an adjacent end of the inner passage in the extension piece, the inner passage comprising a blind axial bore formed over some of the extension piece which has at least one radial passage in the vicinity of the end forming the adjacent valve means, the one axial passage communicating with a central axial end chamber aligned with the inner passage, and the core having a pair of parallel axial passages providing communication between the second insert and inner cylindrical part.