US Patent 9906109 Vibration actuator

A vibration actuator includes: a coil having a vibration space along an axial direction; an outer case that covers the coil and that extends the vibration space in the axial direction; a movable element that comprises a magnet that vibrates within the coil and a weight unit that vibrates within the outer case and that is connected to one end side, in the axial direction, of the magnet; and an elastic member that supports elastically the vibration of the movable element in the axial direction. A resin layer is secured to an outer peripheral surface of the weight unit that faces an inner surface of the outer case. An oil film is interposed between the resin layer and the inner surface of the outer case.