| 摘要 |
PROBLEM TO BE SOLVED: To provide a brake booster capable of stably ensuring the sealability even when a vacuum valve diameter and an air valve diameter are close to each other. SOLUTION: In this brake booster wherein a plunger 28 slid integrally with an input rod 26 and a poppet valve 36 are mounted in a valve body 21 mounted on a power piston, the air valve 37 is formed by a valve seat 29 mounted on a rear end of the plunger 28 and a seal part mounted near an inner diameter of the poppet valve 36, the vacuum valve 38 is formed by a valve seat 32 and a seal part near an outer diameter of the poppet valve 36 on the valve body 21, the air valve 37 is opened by the sliding of the plunger 28 or the movement of a valve seat member 31 driven by a solenoid mechanism 40 to produce the pressure difference to advance the power piston, and two seal parts of the poppet valve 36 are set on a spherical face 70 having a center located on an oscillation center P of the plunger 28 to stably keep the sealability of the air valve 37 and the vacuum valve 38 regardless of the oscillation of the plunger 28. |
