| 摘要 |
Disclosed is a solenoid having a central and a peripheral air gap between the armature and the pole piece. The energizating coil is located in the space between the central core and the peripheral portions of the pole piece and armature. In one embodiment, an output shaft is received in an aperture in the central core of the pole piece and connected to the armature. In preferred embodiments, a longitudinally and radially extending slot is provide to produced eddy current losses. Additionally, mass is removed from non-critical portions of the armature to reduce its weight and increase its acceleration during energization of the solenoid. By utilizing stepped changes in the pole piece and armatures, peripheral portions and central core portions as well as variations in the central and peripheral gaps, the force/distance curve of the solenoid can be tailored to the specific application. In one embodiment, the armature comprises a central core which is moveable relative to the peripheral portion only in the operating direction. This permits a very small peripheral gap to generate high initial acceleration forces which are imparted to the armature central core but does not limit the central core to an inordinately short operating stroke. |
