Abstract: An inertial actuator for active vibration control utilizes a single cylindrical actuator module of the “voice coil” type. A moving armature assembly, including a soft iron shell with a tubular sleeve coaxially surrounding a core with two permanent magnets and corresponding pole plates, is suspended compliantly by a flexure assembly including a multiple-stack array of shaped flexure strips and a pair of end support flexure plates mounted to a base. Two magnetically charged annular air gaps at the pole plates in the moving armature traverse two corresponding annular coils wound in a tubular bobbin that extends as a heat-sinking mounting column attached to the base. This form of inertial actuator provides cost benefits along with improved performance and reliability due to the stability of the moving parts and uniformity of linear motion.

Abstract: For transducers such as loudspeakers and actuators which must operate at unusually low or high ambient temperatures, a robust resilient annular support member for mounting the vibratable diaphragm extends outwardly therefrom to the main frame. The support member is formed from silicone elastomer or a silicone rubber composite in a molding process which may be a constant temperature process, preferably transfer molding. A diaphragm and a surround member may be bonded together in the molding process by inserting the edge of the diaphragm into the cavity mold. The molding techniques of silicone rubber composites containing pulp and weave fiber grades of commercially available mix materials allow transfer, compression or injection molding of diaphragm suspension system members with good control of the mechanical properties and thickness.