Magnetically-efficient solenoid for a linear actuator

摘要

An improved solenoid for providing linear actuation. The outer polepiece of the solenoid is provided with an axial journal bearing for supporting an actuating shaft extending from the solenoid armature. Radial tolerance between the bearing inner bore and the shaft is as small as in practically possible, which feature permits elimination of the prior art portion of the guiding sleeve extending into the outer polepiece, thereby retaining frictional losses with only the remaining sleeve portion in the inner polepiece. Small prior art air gaps at interfaces 42,44 between the polepieces and the housing are eliminated to minimize reluctance of the magnetic circuit. A significant increase in actuating force is realized in comparison with a prior art solenoid actuator.