Patent ID: 7439641

Claim:
A resonance drive actuator comprising: a casing; an electromagnetic drive section supported in the interior of the casing; a plunger to be reciprocatively driven in a rotational direction and in an axial direction by the electromagnetic drive section; an output shaft on which the plunger is fixed; and a plurality of springs which act between the output shaft and the casing, the actuator resonantly driving a load connected to an end of the output shaft; wherein each spring is a plate spring which integrally comprises a casing inner-surface abutment portion fixedly abutting the inner surface of the casing, an output-shaft abutment portion fixedly abutting an outer surface of the output shaft, and a connection portion having the form of a strip and connecting the output-shaft abutment portion and the casing inner-surface abutment portion, and each plate spring is fixed to both of the inner surface of the casing, and the output shaft, said plurality of plate springs being arranged on at least one side in said axial direction of said casing and being comprised of a plurality of sets in which each set has two plate springs having an identical circumferential phase, one plate spring of each set being arranged such that said one plate spring faces a direction opposite to another plate spring, each set having a circumferential phase different from another set.