Master Cylinder Assembly for a Hydraulic Actuation System for a Handlebar-steered Vehicle

A master cylinder assembly for a hydraulic actuation system for a handlebar-steered vehicle, the master cylinder assembly comprising:

• a housing mountable to a handlebar and having a chamber including a fluid cavity and an air cavity, the fluid cavity with first and second regions, the first region in fluid communication with the hydraulic actuation system;
• a piston assembly having a piston slidably disposed within the fluid cavity, the piston having first and second portions;
• an actuator operatively connected to the housing and operatively connected to the piston to slidably displace the piston between an open fluid circuit position and a closed fluid circuit position;
• a first seal disposed on the first portion of the piston and configured to be in sealing engagement between a wall of the fluid cavity and the first portion of the piston with the piston in the closed fluid circuit position to block fluid flow between the first and second fluid cavity regions,
• the first seal configured to be in non-sealing disengagement between the wall of the fluid cavity and the piston with the piston in the open fluid circuit position to permit fluid flow between the first and second fluid cavity regions;
• a second seal disposed on the second portion of the piston and configured to be in sealing engagement between the second portion of the piston and a wall of the second fluid cavity region;
• and
• a flexible bladder having a first end attached to the first portion of the piston and a second end attached to the second portion of the piston, the flexible bladder sealingly separating the fluid cavity from the air cavity.