Magnets In Modern Electromagnetic Devices

摘要

High-energy magnet materials based both on samarium cobalt and neodymium materials have proven to be quite suitable for novel electromagnetic devices. They have proven high performance when applied to rotary actuators and magnetic sensors. The magnet location in respect to the air gap seems to be crucial factor in developing novel high efficiency configurations. However, they require careful size selection since they adversely affect the efficiency of the conventional electromagnetic circuit. For rotary actuators, the ring magnet with multipole radial magnetization shows superior performance providing a high force density of 58kN/m~2. This ring magnet based on NdFeB using both sintered and die quench upset technologies, were successfully developed and their first application in electromagnetic devices were rotary actuators. Nowadays, they are finding many other applications in other electromagnetic devices such as stepper motors, brushless motors, etc. Also novel electromagnetic designs utilizing multipole structures allows for low-energy plastic bonded magnets in automotive applications.