Abstract: Displacements of output portions 35, 36 of a pair of piezoelectric actuators 25, 26 arranged spanwise in a flap drive apparatus are magnified by a displacement magnification mechanism 27 so that a swing arm 28 is driven in swinging fashion with large amplitude. A flap 22 attached to the trailing edge of a blade 21 by way of a connecting rod 30 connected to a tip of the swing arm 28 is driven in vertical angular displacement fashion. The displacement magnification mechanism 27 possesses an eccentric shaft 40 has a first shaft 41 and second shaft 42 with offset axes. An output portion 35 is coupled to the first shaft 41, and an output portion 36 is coupled to the second shaft 42. The swing arm 28 is fixed to the eccentric shaft 40. Displacement of the output portions 35, 36 of the actuators 25, 26 in opposite phase results in a stable swing of the swing arm 28.

Abstract: An actuator and first to fourth links constitute a first displacement magnifying mechanism. An input shaft which is fixed in a basal end of the first and second links, a support shaft which is fixed in a basal end of the third and fourth links, and a displacement magnifying lever constitute a second displacement magnifying mechanism. In the displacement magnifying lever, an intermediate portion is angularly displaceably coupled to a tip end of the support shaft, a tip end of the input shaft is angularly displaceably coupled to one end, and an output rod is angularly displaceably coupled to another end. The expansion and contraction of the actuator are magnified by the first and second displacement magnifying mechanisms so as to drive a flap angularly via output rod. According to this configuration, the displacement of the actuator can be largely magnified so that the flap can be sufficiently angularly displaced in the vertical direction and in a reciprocal manner.

Abstract: A flap is attached to a rear end of a blade so as to be angularly displaceable. Displacement magnifying means magnifies the amount of displacement from an actuator to drive the flap. An input portion to which the displacement is applied from the actuator is expandably and contractibly supported by bellows. Likewise, an output portion to which the input amount of displacement is magnified is expandably and contractibly supported by a bellows. Consequently, displacement magnifying means is realized in which, compared with a existing piston with O ring which slides on the cylinder inner wall, no deterioration in response characteristic due to high friction occurs when the actuator is displaced at high speed, and no fluid leakage due to deterioration or wear of the O ring occurs. According to this structure, a rotor blade flap driving apparatus is obtained which has displacement magnifying means with fast response and no fluid leakage.