| 摘要 |
PURPOSE:To constitute a booster capable of changing a boosting ratio at the time when operating force of an input rod is weak and at the time when it is strong and varying the boosting ratio and a varying point of the boosting ratio at low cost. CONSTITUTION:A housing 10, a power piston 151 partitioned into constant pressure chambers Ra2, Rb2 and variable pressure chambers Ra1, Rb1, a control valve selectively communicating the variable pressure chambers to a high pressure source or the constant pressure chambers and an input rod 41 connected to an air valve are provided. Additionally, a ring groove 431a provided at least in the neighbourhood of an outer periphery of a contact surface with a reaction disc 432 of the output rod in the axial direction is furnished in a differential pressure type booster furnished with the reaction disc 432 transmitting driving force generated on the power piston 151 by pressure differential between the constant pressure chambers and the variable pressure chambers from the power piston to the output rod and adding reaction force to the air valve. |
