ABS hydraulic circuit with a variably open inlet valve

A hydraulic brake system with anti-lock control for controlling the brake system during a lock-up condition that includes an undesirable frictional engagement between a road surface and a vehicle wheel, comprising:

• a master cylinder interconnected through a flow control valve to a wheel brake;
• and
• an auxiliary pressure means connected to said wheel brake, said flow control valve including
• a normally open inlet valve having a variable open position to permit fluid communication between said master cylinder and said wheel brake, said inlet valve being adapted to close when lock-up occurs thereby isolating said master cylinder from said wheel brake;
• and
• a normally closed outlet valve for controlling flow from said wheel brake to said auxiliary pressure means;
• said outlet valve opening to allow auxiliary pressure to communicate with said wheel brake during lock-up.

A hydraulic brake system with anti-lock control, in particular, for automotive vehicles, comprising:

• a main pressure line which leads from a master cylinder to at least one wheel brake and into which an inlet valve is inserted that is normally open;
• an outlet valve coupled with said main pressure line, said outlet valve being closed in its normal position to which a pressure fluid return delivery line is connected;
• a pressure fluid accumulator being connected to the pressure fluid return delivery line;
• and
• an auxiliary pressure pump connected downstream of the pressure fluid accumulator and taking pressure fluid from the pressure fluid accumulator and delivering it via an auxiliary pressure line to the wheel brake, said auxiliary pressure line being connected to the pressure side of the auxiliary pressure pump constituting a permanent direct hydraulic connection to the wheel brake, while the pressure side of the auxiliary pressure pump is adapted to be shut off in relation to the master cylinder by the inlet valve, said inlet valve closing in the direction of the wheel brake and in the direction of the auxiliary pressure line, said outlet valve being a non-return valve that opens in the direction of the return delivery line.

A hydraulic brake system with anti-lock control for controlling the brake system during lock-up, comprising:

• a master cylinder interconnected through a flow control valve to a wheel brake;
• and
• a auxiliary pressure means connected to said wheel brake, said flow control valve including
• a normally open inlet valve normally permitting fluid communication between said master cylinder and said wheel brake, said inlet valve being adapted to close when lock-up occurs thereby isolating said master cylinder from said wheel brake;
• and
• a normally closed outlet valve for controlling flow from said wheel brake to said auxiliary pressure means, said outlet valve opening to allow auxiliary pressure to communicate with said wheel brake during lock-up, said inlet valve closing in the direction of said wheel brake and in the direction of said auxiliary pressure means and said outlet valve being a non-return valve opening in the direction of said auxiliary pressure means.