| 摘要 |
<p>PURPOSE:To prevent a pedal stroke from suddenly increasing temporarily in region exceeding a limit for boosting force by providing such lock member as will fit covering a power piston and a control piston only when a pressure difference on both sides of the power piston exceeds a given value between both pistons in a stroke- enlarged brake booster. CONSTITUTION:A booster 100 doubles an input applied from a brake pedal 101 to an operating rod 1 and puts it out to a master cylinder 102 from a push rod 2 working as an output member. The interior of a casing 3 of the booster 100 is divided into two with a power piston 4, and a control piston 9 is fitted slidably in a through hole of the piston 4. Then, a cylinder bore is formed in a cylinder unit 51 of the piston 9, and a lock piston 53 is inserted movably in said bore. Since a stop projection 54 of the lock piston 53 is fitted in a stopper 59 of the piston 4 at the time of sudden braking, all are unified and an output stroke increases in the same ratio as an input stroke.</p> |
