1. Field of the Invention
The present invention relates to a fluid filled type vibration damping device supporting a power unit to a vehicle body within vibration damping.
2. Description of the Related Art
One of such known fluid filled type vibration damping devices is shown in JP-A-59-151637. The fluid filled type vibration damping device shown in JP-A-59-151637 elastically connects a first mounting member and a second mounting member by a main rubber elastic body, and makes to partition a fluid chamber, which is formed with the main rubber elastic body and the flexible film, into a pressure-receiving chamber on the side of the main rubber elastic body and an equilibrium chamber on the side of the flexible film by a partition member.
Furthermore the fluid filled type vibration damping device shown in JP-A-59-151637 provides a first orifice passage having been tuned to a low-frequency band correspond to shake vibration and a second orifice passage having been tuned to a high-frequency band correspond to idling vibration as orifice passages communicating the pressure-receiving chamber and the equilibrium chamber with each other, and switches these first and second orifice passages by moving the valve by the electromagnetic force occurring by the electrical connection of the coil.
In this way, by controlling the electrical connection of the coil based on the driving state, the vibration damping effect to shake vibration making a problem during driving and the vibration damping effect to idling vibration making a problem at the stop can be produced effectively.
In these fluid filled type vibration damping devices, not described in JP-A-59-151637, the device includes a microcomputer, which produce the control signals based on the driving state, and a power amplifier circuit, which amplify this control signals and connect to the coil electrically, to control the electrical connection of the coil.
Moreover, conventionally a microcomputer and a power amplifier circuit were both mounted on the same circuit board and constituted control unit. Furthermore, this control unit was disposed separately from the main body of the fluid filled type vibration damping device and output of the control unit was supply to the coil by the electric power line.