Portless type master cylinder device with intake valve and flow resisting means between pressure chamber and reservoir chamber

摘要

In this portless type master cylinder device (1), a cylinder bore (2) is formed in a body thereof, and a piston member (3, 4) is fitted in the cylinder bore and is slidably movable from an initial axial position therein and defines a pressure chamber (14) on its one side and a reservoir chamber (17) on its other side in cooperation with the cylinder bore. An intake valve (30) communicates between the cylinder chamber and the reservoir chamber, and is opened when the piston member is in its initial axial position while it is closed when the piston member moves through more than a determinate relatively small axial distance from its initial axial position. Intermediately along the fluid flow path between the intake valve and the reservoir chamber, there is provided a means (34) for presenting a relatively high flow resistance to flow of fluid in the direction from the intake valve to the reservoir chamber. Thereby, in the dynamic operational mode, the stroke of the piston member has a much reduced inactive initial stroke portion, as compared with other portless type master cylinder devices, and the operational feeling of the master cylinder device is greatly improved.