| 摘要 |
<p>A flow regulating valve incorporating a core of ferromagnetic material, a spring which repositions the core, an electromagnet which in turn comprises at least one coil wound onto a magnetic yoke, in which the yoke has an internal cavity in which the core is located so that it can move in an axial direction and a hydraulic circuit controlled by a needle obstructor integrally mounted on the core, is described. The valve is of a shape such that the magnetic reluctance of a magnetic circuit comprising the yoke, the electromagnet and the core is maintained substantially almost constant as the relative axial position between the core and the yoke changes, and, in combination, the spring is housed so as to bear against an axial shoulder in the cavity and one end of the core so that in use it exerts a return force against the core, the change in which resulting from relative displacement between the yoke and the core is greater than the change in the attractive force exerted on the core by the electromagnet as a result of that displacement. <IMAGE></p> |
