Pneumatic servomotor for braking assistance of a vehicle, retaining the feeling in the brake pedal

摘要

The servomotor (1) has a hydraulic fluid reservoir (14) in communication with a primary chamber (2) of a master cylinder (3) via a channel (15). A closing unit is provided with a valve (16), a sliding part (17) and an elastic unit (18) e.g. spring, to close the channel, where function of the closing unit is dependent on hydraulic pressure in the chamber. The reservoir is formed by a sealed skirt (7) and a moving part (6). The skirt and the moving part slid with respect to each other while defining a space whose volume varies according to the skirt that is rigid with respect to the moving part.