| 摘要 |
The valve includes an electromagnetic solenoid actuator having a magnetic circuit defined by a primary and a secondary pole piece. The pole pieces define an axial chamber in which is disposed an axially movable armature and an associated valve member. The primary pole piece has a centre pole member including a cylindrical inner wall which is open at a first end for receiving the armature. The armature and the cylindrical inner wall establish a fixed, radially extending primary air gap for flux passage while the outer wall extends in an outward taper from the first, open end of the centre pole member and operates to increase the mass of the pole piece through which the magnetic circuit operates as the armature moves from the first, open end of the centre pole member towards the second end. The secondary pole piece has a centre pole member which includes a cylindrical inner wall, open at a first end for receiving the movable armature and which is located in spaced opposing relationship to the first, open end of the primary pole to define a pole-to-pole gap between them. The armature and the cylindrical inner wall of the secondary pole define fixed, radially extending primary air gap for flux passage across it, and the outer wall extends in an outward taper from the first, open end. The outwardly tapering walls of primary and secondary poles operate to minimize the pole-to-pole gap through a minimization in opposing surface area between them allowing the length of the secondary pole and the surface area between secondary pole member and the armature to be maximized. |
