| 摘要 |
PURPOSE:To prevent the generation of pressure rise delay, defective return, pedal pressure increase, and the like by disposing a sleeve, extended parallel to a valve plunger, between the valve plunger and a reaction member on the valve plunger side. CONSTITUTION:In association with the advance of a valve plunger 11, the pressure receiving area of the valve plunger to a reaction member 22 is increased stepwise, and the power boosting ratio of power outputted to a braking device from an output rod 18 in relation to operating force supplied to an input rod 13 is reduced stepwise before reaching a reinforcing limit point. The change of brake operating feelings around the reinforcing limit point is thereby relaxed without lowering the power boosting ratio in a normal service region. Since the valve plunger 11 slides in a sleeve 23a to come in contact with the reaction members 21, 22, the internal pressure of the reaction member 22 on the valve plunger 11 side is applied only to the sleeve 23a but not to the valve plunger 11. |
