Tadao Takagi

Vibration actuator with two vibration modes

A vibration actuator includes a vibration element, which simultaneously generates a radial symmetric expansion vibration mode in which it expands and contracts in the radial direction and a non-axisymmetric planar vibration mode in which it bends to and fro in a non-axisymmetric manner within a single plane, and thereby drives a relative movement member, and a base member to which the vibration element is fixed. The vibration element includes at least one superimposed layer structure comprising a pair of electrical energy to mechanical energy conversion elements and an elastic member sandwiched between the pair of electrical energy to mechanical energy conversion elements. The elastic member includes a ring shaped portion to both the sides of which the pair of electrical energy to mechanical energy conversion elements are stuck, and a cylindrical shaped support portion, formed integrally with the ring shaped portion, which fixes the vibration element to the base member. The support portion includes an elastic portion which suppresses the transmission of vibration generated by the vibration element to the base member.