Master cylinder

A master cylinder comprising a primary piston disposed to be reciprocable within an axial bore of housing toward a rear end thereof and stepped to include a reduced diameter portion and an increased diameter portion;

• a secondary piston disposed to be reciprocable within the axial bore of the housing toward a front end thereof and having an axial bore which opens in the rearward direction;
• a first sleeve disposed rearward of the secondary piston and slidably fitted into the inner peripheral surface of the housing;
• a first reservoir chamber defined by the inner peripheral surface of the axial bore of the secondary piston and the reduced diameter portion of the primary piston and into which a braking liquid in a reservoir is normally introduced;
• a first liquid pressure chamber defined by the increased diameter portion of the primary piston, the first sleeve and the inner peripheral surface of the housing;
• and a second liquid pressure chamber formed adjacent to the secondary piston within the housing for generating a liquid pressure therein as the secondary piston is driven forward;
• characterized in that the reduced diameter portion of the primary piston is slidably fitted into the axial bore in the secondary piston, a retraction limit member which defines a retraction end of the primary piston being mounted on either the first sleeve or the secondary piston.