BigPatents India

The invention relates to a tandem hydraulic master cylinder mainly comprising a body (1) pierced with a bore, first and second inlets (2a, 2b) for a hydraulic fluid at low pressure, a primary piston (3) and a secondary piston (4) which slide respectively in first and second length sections (S1, S2), a primary pressure chamber (5), a secondary pressure chamber (6), first and second upstream and downstream sealing cups (91a, 91b, 92a, 92b), first and second resupply ducts (21, 22) and first and second outlet orifices (41 and 42) for the pressurized hydraulic fluid. According to the invention, the primary and secondary pistons (3, 4) are guided by the wall (100) of the bore, with which they are in contact, and the body (1) is further pierced with a first longitudinal passage (51) connecting the first downstream cup (91b), the second upstream cup (92a) and the first outlet orifice (41) and communicating with the primary pressure chamber (5) via a first radial passage (61) situated between the first and second length sections (S1, S2). (FIG.)nil