COMPOUND BRAKE BOOSTER AND MASTER CYLINDER ASSEMBLY BODY

摘要

PURPOSE: To enable a driver to apply the brake without operating a brake pedal by keeping movable front and rear partitions separate from each other, and forming a passage for connecting the two front chambers in a cylindrical extension of a piston of a master cylinder. CONSTITUTION: A front space A is divided into a front chamber 12 and a rear chamber 14 by a movable partitions 16, and a rear space B is divided into a front chamber 18 and a rear chamber 20 by a movable partition 22. Diaphrams 24, 26 are provided at the respective movable partitions 16, 22, and the outer peripheral edge parts of the diaphrams are respectively fastened to an external casing 10 in hermetically sealed manner to airtightly separate the front chambers 12, 18 from the rear chambers 14, 20 in respective spaces. When a passage to a solenoid valve 56 is controlled to a second position to shut off the communication between the rear chambers 14 and 20, and the rear chamber 14 is connected to an air source 58 of atmospheric pressure, the movable partition 16 is moved forwardly together with a piston 32 to take the necessary braking action, since low pressure constantly exists in the front chamber 12. On the other hand, since a clearance exists between a cylindrical extension 30 of the piston and an output rod 42, the output rod 42 or an input rod 27 is not moved with the movement of the piston.