Patent ID: 6907731

Claim:
In a master cylinder apparatus with a booster comprising: a booster shell; a partition member dividing the interior of the booster shell into a variable-pressure chamber and a constant-pressure chamber; a piston attached to the partition member for transmitting the movement in a front-rear direction of said partition member responsive to the pressure difference between the variable-pressure chamber and the constant-pressure chamber, to an output member; a control valve disposed in the piston to regulate the communication of the variable-pressure chamber with the constant-pressure chamber and the atmosphere; a cylinder body provided with a cylinder that opens to an end thereof and an installation flange at the same end to which the booster is secured; a master piston slidably inserted in the cylinder and connected to the output member; a reaction force generating device interposed between the piston and the output member to make a reaction force act on a valve body of the control valve; pull means connected to a brake pedal at one end and to the valve body at the other end, and wherein: the installation flange is attached to a dashboard, so that the booster shell is disposed in one of a passenger room and an engine room and the cylinder body protrudes into the other room through an installation hole made through the dashboard.