| 摘要 |
PURPOSE:To effectively improve the ability to control the inner pressure of a fluid chamber by eliminating or reducing the action of an air spring to be generated in the space within a bobbin to be formed between the opposite surfaces of a first yoke arranged on a vibrating plate side of a permanent magnet and the bobbin connected to the vibrating plate. CONSTITUTION:A permanent magnet 50 is arranged at the back of a vibrating plate 30 consisting of a part of a wall part of a liquid chamber, and a first and a second yokes are connected to the respective ends of the permanent magnet 50 to form the magnetic path having an annular gap part 62. A bobbin 64 to hold a driving coil 69 at the cylindrical wall part 68 is arranged in an integrated and displaceable manner between the opposite surfaces of the gap part 62, and in addition, a communicating means to communicate an inner space 74 to be formed between the bottom inner surface of the bobbin 64 and the first yoke through the wall part of the bobbin 64 with the space outside the bobbin 64, and the bobbin 64 is connected to the vibrating plate 30 to excite the vibrating plate 30 through electrification to the driving coil 69. |
