Patent ID: 7609148

Claim:
An actuator comprising: a diaphragm that vibrates to generate sound; a housing that is attached to an outer edge of the diaphragm to support the diaphragm; an accommodating space that is formed inside the diaphragm and the housing, and an axis of which extends in a thickness direction of the diaphragm in the middle of the diaphragm; a coil that is wound around the axis, is attached to a face of the diaphragm facing the accommodating space, and is disposed in the accommodating space; a movable body that is disposed in a radial inside space of the coil or on an extension of the radial inside space, within the accommodating space; and a spring that supports the movable body such that the movable body is movable in the axial direction within the accommodating space, wherein, when an electrical signal is supplied to the coil, the coil and the movable body are caused to move relatively in the axial direction, thereby vibrating the diaphragm to generate sound, and the vibration of the movable body vibrates the housing, wherein the movable body is provided with a weight increasing member that increases the weight of the movable body, wherein the movable body includes a magnet, and a yoke that is attached to the magnet, the movable body constituting a magnetic circuit that leads lines of magnetic force from the magnet to the coil, wherein a part that increases the weight of the yoke is formed in the yoke, and wherein the weight increasing member includes the part of the yoke.