| 摘要 |
<p>PURPOSE:To omit a hydraulic transfer pipe line as well as to improve reliability in a control unit, by installing a piezoelectric control cylinder in a wheel cylinder, while operating this piezoelectric control piston with a brake operation detecting signal and performing its control. CONSTITUTION:A control unit (unillustrated herein) emits a braking command with a brake operation signal, lowering voltage to be fed to a piezoelectric mechanism 272 of a piezo-piston 27, and makes the capacity smaller. Therefore, a control piston 273 moves in a direction where an oil chamber 28 expands, and simultaneously a volumetric control piston 30 also moves so as to expand the capacity of an oil chamber 23. Under this condition, the control unit closes a control valve 34 and closes up the oil chamber 23 tight. After that, high voltage is fed to the piezoelectric mechanism 272, and when the piezo-piston 27 is expanded longer, the volumetric control piston 30 is driven whereby oil pressure is produced in the oil chamber 23. With this oil pressure, a brake piston 22 is driven, thus braking takes place. Feed voltage of the piezo-piston 27 is controlled whereby braking pressure is controlled.</p> |
