Auxiliary power assisted master cylinder arrangement for a vehicle brake system

A master cylinder arrangement for use in conjunction with an auxiliary source of pressurized fluid in a braking system, especially of a vehicle, for controlling the effective pressure of a hydraulic braking fluid in at least one braking circuit incorporating at least one brake actuating cylinder, in dependence on the position of a brake operating member, especially a brake pedal, comprising

• at least one master cylinder unit, including means for bounding a master cylinder bore, and a master piston received in said master cylinder bore for axial movement therein and subdividing said bore into a primary compartment communicating in use with the braking circuit, and a secondary compartment;
• a brake control valve unit interposed in use between the auxiliary source and said secondary compartment and operative for controlling the pressure in the latter;
• means for operating said brake control valve unit in dependence on the position of the brake operating member in use, including
• a travel simulator preceding said brake control valve unit as considered in the direction of force transmission from the brake operating member to said brake control valve unit;
• means for directly coupling said master piston with said operating means for joint movement therewith at least in said direction and at least upon failure of the auxiliary source;
• wherein said coupling means includes a cylinder-and-piston unit operatively connected to the brake operating member and acted upon during normal operation with the auxiliary source operational in direction toward the brake operating member by a pressure derived from the auxiliary source, and a first mechanical link extending from said cylinder-and-piston unit to said master piston;
• wherein said operating means further includes a second mechanical link extending from said cylinder-and-piston unit to said travel simulator;
• and further comprising means for interlocking said mechanical links upon failure of the auxiliary source;
• and
• further comprising a common housing accommodating said units and said operating and coupling means and a reservoir for the hydraulic fluid formed integrally in said housing;
• and wherein said first and second mechanical links are situated in said reservoir.

A master cylinder arrangement for use in conjunction with an auxiliary source of pressurized fluid in a braking system, especially of a vehicle, for controlling the effective pressure of a hydraulic braking fluid in at least one braking circuit incorporating at least one brake actuating cylinder, in dependence on the position of a brake operating member, especially a brake pedal, comprising

• at least one master cylinder unit, including means for bounding a master cylinder bore, and a master piston received in said master cylinder bore for axial movement therein and subdividing said bore into a primary compartment communicating in use with the braking circuit, and a secondary compartment;
• a brake control valve unit interposed in use between the auxiliary source and said secondary compartment and operative for controlling the pressure in the latter;
• means for operating said brake control valve unit in dependence on the position of the brake operating member in use, including
• a travel simulator preceding said brake control valve unit as considered in the direction of force transmission from the brake operating member to said brake control valve unit;
• means for directly coupling said master piston with said operating means for joint movement therewith at least in said direction and at least upon failure of the auxiliary source;
• wherein said coupling means includes a cylinder-and-piston unit operatively connected to the brake operating member and acted upon during normal operation with the auxiliary source operational in direction toward the brake operating member by a pressure derived from the auxiliary source, and a first mechanical link extending from said cylinder-and-piston unit to said master piston;
• wherein said operating means further includes a second mechanical link extending from said cylinder-and-piston unit to said travel simulator;
• and further comprising means for interlocking said mechanical links upon failure of the auxiliary source;
• and
• wherein said cylinder-and-piston unit includes means for defining a receiving bore, a hollow outer piston guided in said receiving bore, and an inner piston guided within said outer piston and coupled with the brake operating member, said inner and outer pistons together bounding an inner chamber;
• and wherein said interlocking means includes an auxiliary power conduit communicating with said inner chamber, and means for interrupting communication through said auxiliary conduit to form a hydraulic lock in said inner chamber;
• and wherein said first mechanical link is connected to said outer piston at the end of the latter which is closer to the brake operating member, and said second mechanical link is connected to said inner piston at the end of the latter which is closer to the brake operating member.

A master cylinder arrangement for use in conjunction with an auxiliary source of pressurized fluid in a braking system, especially of a vehicle, for controlling the effective pressure of a hydraulic braking fluid in at least one braking circuit incorporating at least one brake actuating cylinder, in dependence on the position of a brake operating member, especially a brake pedal, comprising

• at least one master cylinder unit, including means for bounding a master cylinder bore, and a master piston received in said master cylinder bore for axis movement therein and subdividing said bore into a primary compartment communicating in use with the braking circuit, and a secondary compartment;
• a brake control valve unit interposed in use between the auxiliary source and said secondary compartment and operative for controlling the pressure in the latter;
• means for operating said brake control valve unit in dependence on the position of the brake operating member in use, including
• a travel simulator preceding said brake control valve unit as considered in the direction of force transmission from the brake operating member to said brake control valve unit;
• means for directly coupling said master piston with said operating means for joint movement therewith at least in said direction and at least upon failure of the auxiliary source;
• wherein said coupling means includes a mechanical link, and locking means preceding said master piston as considered in the direction of force transmission from the brake operating member to said piston and ineffective for force transmission during normal operating conditions with the auxiliary source operational, and becoming effective for coupling said master piston to said mechanical link for joint movement therewith at least in said direction upon failure of the auxiliary source;
• and
• wherein said locking means is a hydraulic means.

A master cylinder arrangement for use in conjunction with an auxiliary source of pressurized fluid in a braking system, especially of a vehicle, for controlling the effective pressure of a hydraulic braking fluid in at least one braking circuit incorporating at least one brake actuating cylinder, in dependence on the position of a brake operating member, especially a brake pedal, comprising

• at least one master cylinder unit, including means for bounding a master cylinder bore, and a master piston received in said master cylinder bore for axial movement therein and subdividing said bore into a primary compartment communicating in use with the braking circuit, and a secondary compartment;
• a brake control unit interposed in use between the auxiliary source and said secondary compartment and operative for controlling the pressure in the latter;
• means for operating said brake control valve unit in dependence on the position of the brake operating member in use, including
• a travel simulator preceding said brake control valve unit as considered in the direction of force transmission from the brake operating member to said brake control valve unit;
• means for directly coupling said master piston with said operating means for joint movement therewith at least in said direction and at least upon failure of the auxiliary source;
• wherein said coupling means includes a mechanical link, and locking means preceding said master piston as considered in the direction of force transmission from the brake operating member to said master piston and ineffective for force transmission during normal operating conditions with the auxiliary source operational, and becoming effective for coupling said master piston to said mechanical link for joint movement therewith at least in said direction upon failure of the auxiliary source;
• and
• wherein said master cylinder unit further includes a deflectable lip seal surrounding said master piston, means for biasing said master piston opposite to said direction, a piston tappet axially slidably received in said master cylinder bore, and means for limiting the extent of movement of said piston tappet opposite to said direction, said piston tappet having a larger-diameter position axially delimiting said secondary chamber, and a smaller-diameter portion extending from said larger-diameter portion toward said master piston and having a cross-sectional area smaller than the latter to delimit a clearance in said secondary chamber.

A master cylinder arrangement for use in conjunction with an auxiliary source of pressurized fluid in a braking system, especially of a vehicle, for controlling the effective pressure of a hydraulic braking fluid in at least one braking circuit incorporating at least one brake actuating cylinder, in dependence on the position of a brake operating member, especially a brake pedal, comprising

• at least one master cylinder unit, including means for bounding a master cylinder bore, and a master piston received in said master cylinder bore for axial movement therein and subdividing said bore into a primary compartment communicating in use with the braking circuit, and a secondary compartment;
• a brake control valve unit interposed in use between the auxilary source and said secondary compartment and operative for controlling the pressure in the latter;
• means for operating said brake control valve unit in dependence on the position of the brake operating member in use, including
• a travel simulator preceding said brake control valve unit as considered in the direction of force transmission from the brake operating member to said brake control valve unit;
• means for directly coupling said master piston with said operating means for joint movement therewith at least in said direction and at least upon failure of the auxiliary source;
• wherein said coupling means includes a mechanical link, and locking means preceding said master piston as considered in the direction of force transmission from the brake operating member to said master piston and ineffective for force transmission during normal operating conditions with the auxiliary source operational, and becoming effective for coupling said master piston to said mechanical link for joint movement therewith at least in said direction upon failure of the auxiliary source;
• and
• and further comprising additional locking means succeeding said brake control valve unit as considered in the direction of force transmission from the brake operating member to said brake control valve unit and operative for opposing the movement of said brake control valve unit and of said travel simulator in the latter direction during normal braking operation with the auxiliary source operational and for releasing said brake control valve unit and said travel simulator for such movement upon failure of the auxiliary source.

A master cylinder arrangement for use in conjunction with an auxiliary source of pressurized fluid in a braking system, especially of a vehicle, for controlling the effective pressure of a hydraulic braking fluid in at least one braking circuit incorporating at least one brake actuating cylinder, in dependence on the position of a brake operating member, especially a brake pedal, comprising

• at least one master cylinder unit, including means for bounding a master cylinder bore, and a master piston received in said master cylinder bore for axial movement therein and subdividing said bore into a primary compartment communicating in use with the braking circuit, and a secondary compartment;
• a brake control valve unit interposed in use between the auxiliary source and said secondary compartment and operative for controlling the pressure in the latter;
• means for operating said brake control valve unit in dependence on the position of the brake operating member in use, including
• a travel simulator precdeding said brake control valve unit as considered in the direction of force transmission from the brake operating member to said brake control valve unit;
• means for directly coupling said master piston with said operating means for joint movement therewith at least in said direction and at least upon failure of the auxiliary source;
• further comprising solenoid-operated valves interposed in the braking system and operative for controlling the anti-skid operation of the latter;
• including at least two additional braking circuits each incorporating at least one additional brake actuating cylinder;
• further comprising an additional master cylinder unit similar to said master cylinder unit and arranged in parallel thereto;
• wherein said primary compartment of said additional master cylinder unit communicates with a first of the additional braking circuits so that said master cylinder units respectively statically actuated the brake actuating cylinders incorporated in the one and the first additional braking circuits;
• wherein said brake control valve unit is arranged in parallel to said master cylinder units and includes means for defining a bore, and a valve body slidably received in said bore and delimiting a control compartment therein which communicates with the second of the additional braking circuits for dynamically actuating the brake actuating cylinders incorporatd therein;
• and further comprising means for communicating said control compartment of said brake control valve unit with said secondary compartments of said master cylinder units;
• and
• wherein said communicating means includes separate auxiliary pressure conduits each communicating with one of said secondary compartments;
• and further comprising means for selectively disconnecting said auxiliary pressure conduits from said control compartments, and means for relieving the pressure in said auxiliary pressure conduits.

A master cylinder arrangement for use in conjunction with an auxiliary source of pressurized fluid in a braking system, especially of a vehicle, for controlling the effective pressure of a hydraulic braking fluid in at least one braking circuit incorporating at least one brake actuating cylinder, in dependence on the position of a brake operating member, especially a brake pedal, comprising

• at least one master cylinder unit, including means for bounding a master cylinder bore, and a master piston received in said master cylinder bore for axial movement therein and subdividing said bore into a primary compartment communicating in use with the braking circuit, and a secondary compartment;
• a brake control valve unit interposed in use between the auxiliary source and said secondary compartment and operative for controlling the pressure in the latter;
• means for operating said brake control valve unit in dependence on the position of the brake operating member in use, including
• a travel simulator preceding said brake control valve unit as considered in the direction of force transmission from the brake operating member to said brake control valve unit;
• means for directly coupling said master piston with said operating means for joint movement therewith at least in said direction and at least upon failure of the auxiliary source;
• further comprising solenoid-operated valves interposed in the braking system and operative for controlling the anti-skid operation of the latter;
• including at least two additional braking circuits each incorporating at least one additional brake actuating cylinder;
• further comprising an additional master cylinder unit similar to said master cylinder unit and arranged in parallel thereto;
• wherein said primary compartment of said additonal master cylinder unit communicates with a first of the additional braking circuits so that said master cylinder units respectively statically actuated the brake actuating cylinders incorporated in the one and the first additional braking circuits;
• wherein said brake control valve unit is arranged in parallel to said master cylinder units and includes means for defining a bore, and a valve body slidably received in said bore and delimiting a control compartment therein which communicates with the second of the additional braking circuits for dynamically actuating the brake actuating cylinders incorporated therein;
• and further comprising means for communicating said control compartment of said brake control valve unit with said secondary compartments of said master cylinder units;
• and
• further comprising a compensating conduit interconnecting said master cylinder units, a compensating cylinder unit interposed in said compensating conduit, and a normally open two-way, two-position directional control valve interposed in said compensating conduit and closing the same upon occurrence of brake slip control condition relating to the brake actuating cylinders incorporated in the one and the first additional braking circuit.