| 摘要 |
PURPOSE: To restrain transmission of acoustically effective vibration by forming a permanent magnet and an electromagnetic coil so that they may not be relatively moved, immovably arranging it on an outer sheath of a rubber mounting, and constituting a lifting magnet for making use of a plate as a magnetic yoke from the permanent magnet and the electromagnet coil. CONSTITUTION: A permanent magnet 8 and an electromagnet coil 9 are so formed as not to be relatively moved, and immovably arranged on an outer sheath 6. The magnet 8 and the electromagnet coil 9 constitute a lifting magnet which uses a plate 3 as a magnetic yoke, and the strength of a spring 2 is larger than that of an expansion spring 5 under the condition in which the lifting magnet and the plate 3 are separated from each other in all using states. The spring 2 is preloaded by the magnet 8, and the plate 3 is placed close to the magnet 8 with a small clearance. Accordingly, oscillation of the plate 3, to be obtained in the operation of the electromagnet coil 9 is very small. Fluid filled in a working chamber 1 is reciprocated to the required extent for compensation of acoustically effective vibration, and the vibration generates no pressure change in the working chamber. |
