| 摘要 |
PROBLEM TO BE SOLVED: To provide a linear driver for driving a load silently with high initial driving force while suppressing subsequent lowering of driving force by conducting an exciting coil and driving an actuator against the resiliency of a spring with magnetic attraction between a first ring and a first column. SOLUTION: When an exciting coil 5 is conducted, a flux passes through a closed circuit of a pole 4a→a column 1a→a column 1d→a column 1b→a pole 4b→a tube 2. Since the quantity of flux is increased, driving force of a column 1, i.e., the actuator in the direction of arrow A, is increased and a load B is driven in the direction of arrow A while resisting against the resiliency of a spring 6. Vertical attraction is not present between the column 1a and the pole 4a but since the facing area is large at the air gap part between them 1a, 4a, magnetic resistance is significantly low and thereby the quantity of magnetic line of force is increased. The magnetic line of force is the leakage flux at the facing part of the column 1b and the pole 4b and since it is directed in the direction of arrow C, it contributes significantly to the driving force in the direction of arrow A thus producing a large driving force.
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