| 摘要 |
PURPOSE:To prevent the tight contact of a diaphragm with a magnet member side and to improve a vibration-proof characteristic. CONSTITUTION:A magnet member 7 formed with an electromagnet 10 and a permanent magnet 11 is mounted on a shell 1. A diapheagm 5 is opposed with a prescribed gap to this magnet member 7. A leaf spring 12 is mounted on the shell 1 so that a part of the leaf spring comes into contact with a part of the diaphragm 5. The contact part of the diaphragm 5 with the leaf spring 12 is formed in a suitably curved surface. When the diaphragm 5 is driven to reciprocate as a result of the cooperation of the electromagnet 10 and the permanent magnet 11, the contact point of the diaphragm 5 to the leaf spring 12 is displaced and the load-deflection feature of the leaf spring 12 changes in terms of exponential function. |
