| 摘要 |
PURPOSE:To reduce a vibrational impact with one piston as well as to improve a damping effect by installing a second air chamber connected to a first air chamber of an air spring, and varying the capacity of this air chamber with such a piston as being driven by an active damper. CONSTITUTION:In this method, there is provided with a sensor 6 for detecting a vibration in a surface plate 2. Output of this sensor 6 is subjected to a signal process at a control part 7, and on the basis of a control signal being outputted out of this control part 7, a piston 17 for moving a bottom surface of a second air chamber 15, connected tandem to the lower part of a first air chamber 12 in an air spring 10, up and down is driven by a linear motor (active damper) 16, varying capacity of this second air chamber 15, and thereby vibration in the surface plate 2 is precisely damped. At this time, capacity of the first air chamber 12 is varied in the same direction as vibrational displacement in the surface plate 2, and the piston 17 is driven by a resultant force consisting of force in direction of lowering the apparent characteristic frequency of the air spring 10 and such force as coming to minus displacement when the piston 17 goes up due to vibration of the surface plate 2 and coming to plus displacement at the time of its going down. |
