Magnetic circuit unit for loud-speaker and method of manufacturing the same.

摘要

A magnetic circuit unit for a loud-speaker is provided, in which an adhesion step can be reduced or omitted, magnetic properties can be improved through enhancement of magnetic efficiency, and a durable anti-corrosive treatment can be performed at low price, so that higher performance and lower cost of the loud-speaker can be attained. A method of manufacturing the same is also provided. A top plate 2 has a conical, columnar, truncated conical, or partially spherical hollow part formed on one side whose inner surface is integrated with an anisotropic Nd-Fe-B system magnet 1 under a forming pressure of 100 to 200 kgf/cm<2> through Joule heating by passing a current under compression. The forming die is cooled to a temperature below 100 DEG C while maintaining the pressure, and the compact is then taken out from the forming die. This integrated compact is adhered to an outer yoke 3, and a looped yoke and a loop anisotropic Nd-Fe-B system magnet are also adhered thereon to fabricate a magnetic circuit unit. Subsequently, this magnet circuit unit is dipped in acrylic resin emulsion, and a coating of 7 to 15 mu m thick is formed by using a rotary coating device.