| 摘要 |
<p>PURPOSE:To make pedal operation feeling satisfactory, and to reduce the ineffective stroke of a piston in a portless type master cylinder device, by providing a flow limiting means in a communication passage communicating an inlet valve with a reservoir communication chamber. CONSTITUTION:When a brake pedal is depressed, two pistons 3, 4 in a master cylinder are moved leftward by means of a rod 49, overcoming springs 7, 8, and therefore, when a piston cup 43 has passed by an orifice port 21, the internal pressure of a first pressure boost chamber 14 is raised. Further, at this time an inlet valve is moved rightward by means of a spring 33 so that the inlet valve is seated on a valve seat section 32 to close the valve, and therefore, the internal pressure of a second pressure boost chamber 15 is increased. Although fluid in the second pressure boost chamber 15 flows into the reservoir communication chamber 17 through an orifice passage 34 until the valve 30 is completely closed, at this time the ineffective stroke of the piston is reduced due to the restricting effect of the orifice passage 34, thereby it is possible to enhance the responsiveness of the master cylinder device.</p> |
