Motor vehicle braking system

In a fluid operated motor vehicle braking system for at least two wheels of one axle of the vehicle, of the type comprising

• main braking pressure generating means,
• means for applying braking pressure from said main braking pressure generating means to brake actuators of both wheels of said axle for simultaneous braking of said two wheels of said axle,
• auxiliary braking pressure generating means, and
• means for applying a reduced braking pressure generated by said auxiliary braking pressure generating means to one of said wheels of said axle if its dynamic state approaches a skid or incipient skid state, while continuing to apply the full braking pressure to the other wheel of said axle if it is not in a skid or an incipient skid state,
• the improvement wherein:
• said means for applying a reduced braking pressure generated by said auxiliary braking pressure generating means comprises:
• distribution means associated with each wheel of said axle, said distribution means including,
• an electrovalve,
• a distributor,
• a first port of said distributor connected to said main braking pressure generating means,
• a second port of said distributor connected to a brake pipe leading to the brake actuator of an associated wheel of said axle,
• a third port of said distributor connected to a conduit leading to said auxiliary braking pressure generating means,
• a main chamber of said distributor,
• a main valve shutter slidingly housed in said main chamber and separating said main chamber into first and second compartments said first compartment communicating with both said first and said second ports,
• means defining a first communication passage leading from said second compartment to said electrovalve,
• means defining a second communication passage leading from said third port to said electrovalve,
• a valve shutter of said electrovalve controlling communication between said first communication passage and said second communication passage whereby to close communication between said third port and said second compartment of said main chamber when said electrovalve is in a first operating position and to open such communication when said electrovalve is in a second operating position, said main shutter being displaced by pressure in said second compartment of said main chamber when said electrovalve is in said second operating position whereby to close communication between said first and said second ports and to open communication between said third and said second ports.