| 摘要 |
<p>A stepped piston is axially displaceable in the stepped piston valve chamber and has a front face facing the front face of the valve seat and an axially opposite surface formed at the juncture of its piston head portion to its reduced diameter shaft portion. The piston has an axial through-bore that opens to fluid connecting bore in the valve housing while the housing has a second fluid connecting bore. The piston is displaceable in the chamber between an open position permitting substantial fluid flow between the connecting bores and a closed position having its front face resting against the valve seat face to permit a leakage flow gap between the faces when pressurized fluid acts against the piston surface and block substantial fluid flow between the first bore and the second bore. A spring in the chamber urges the piston toward its closed position. An insert deformable under a physical parameter, for example made of one of a piezo-electric material and a magnetostrictive material, is arranged in one of the front faces such that the gap is enlarged when the insert contracts the pressure on the piston front face changes and the piston moves from one of its position to the other. One of the connecting bores is an outlet bore and the other is pressurized fluid inlet.</p> |
