Dynamic transducer with moving coil in an air gap filled with magnetic liquid

摘要

A dynamic electroacoustic transducer comprising a magnetic pole case defining a magnetic air gap, a coil movably mounted in the air gap and spaced from the magnetic pole case with magnetic liquid extending between the coil and the case in the air gap. A diaphragm is connected to the coil and attached peripherally to the magnetic pole casing so that airtight spaces are defined above and below the coil which are in communication with each other. The airtight sealing of the spaces prevents the liquid portions of the magnetic liquid to evaporate which would result in deterioration of the characteristics of the dynamic electroacoustic transducer.