Magnetostrictive Vibration Actuator with Improved Characteristics at Low Frequencies

抄録

Giant magnetostrictive element has an advantage in excitation force at high frequencies, but has a weakness in the ability to produce vibration power at low frequencies. The purpose of this paper is to develop a new vibration actuator with improved characteristics at low frequencies by using electromagnetic force to assist the magnetostrictive element. A prototype of the actuator is designed and fabricated. The characteristics of the actuator are measured. The results of measured acceleration or force show an efficient excitation at high frequencies due to magnetostrictive element. It is also shown that the electromagnetic force improves the characteristics at low frequencies where the acceleration amplitude is flat at frequencies below 1kHz. It is confirmed that the magnetostrictive force and electromagnetic force are cooperatively working in this actuator. In addition, the actuator has an advantage in easiness of attachment to or removal from the wall because it sticks to the wall with magnetic force derived from the magnet equipped to produce bias magnetic flux in the magnetostrictive element. This allows flexible location selection of actuators when the actuators are used for vibration control.