Threshold valve adjusting method for a pneumatic brake booster and servomotor to carry out this method

摘要

The invention relates to a threshold value adjusting method for a brake-boosting servomotor which are mounted in a movable fashion a hollow booster piston (20), a control rod (30) carrying a plunger (28) accommodated in the piston (20), the rear end of the plunger (28) forming a first annular valve seat (28a) concentric with a second annular valve seat (20a) carried by the booster piston (20), the first (28a) and second (20a) valve seats acting in concert with an annular valve (34) carried by the booster piston (20), a back-pressure disc (48) being inserted between one front annular face (20b) of the booster piston (20) and a rear face of a pushrod (46). …??According to the invention the method comprises the following stages: … …   - Applying to the pushrod (46) a force equal to the booster force corresponding to the desired increase of the servo motor, …   - Separating the seat (20a) of the booster piston (20) from the valve (34), …   - Bringing the front face of the sensor (28) and the rear face of the back-pressure disc (48) into contact and maintaining this contact throughout the following stage, …   - Bringing the seat (20a) of the booster piston (20) into contact with the valve (34) in order to separate the latter from the seat of the sensor 28a and …   - Releasing the force applied to the pushrod (46). … …IMAGE…