Hydraulic power steering system

A hydraulic power steering system, comprising:

• a steering actuator;
• a first subsystem including a flow-control valve arrangement including a release valve;
• a second subsystem including a flow-control valve arrangement including a release valve;
• and
• a fault detection device,
• wherein:
• the first subsystem and the second subsystem are configured to control the steering actuator in opposite steering directions;
• the fault detection device is configured to:
• (i) determine and deactivate a faulty component of the first subsystem or the second subsystem;
• and (ii) cause a fault-free component of the first subsystem or the second subsystem to maintain control of the steering actuator;
• each of the flow-control valve arrangement of the first subsystem and the flow-control valve arrangement of the second subsystem includes an inlet valve and a discharge valve, the inlet valve and the discharge valve being continuous-control valves configured to be electrically actuated by control signals that, when the control signals are compared with each other by the fault detection device and a deviation from reference data is determined, lead to deactivation of at least one of the release valves or the continuous-control valves that is detected as faulty;
• the release valves are 4/3-way directional valves;
• and
• the continuous-control valves are flow-control valves.

A hydraulic power steering system, comprising:

• a steering actuator;
• a first subsystem including a flow-control valve arrangement including a release valve;
• a second subsystem including a flow-control valve arrangement including a release valve;
• a fault detection device;
• electrical signal lines;
• and
• actuating solenoid devices,
• wherein:
• the first subsystem and the second subsystem are configured to control the steering actuator in opposite steering directions;
• the fault detection device is configured to:
• (i) determine and deactivate a faulty component of the first subsystem or the second subsystem;
• and (ii) cause a fault-free component of the first subsystem or the second subsystem to maintain control of the steering actuator;
• each of the flow-control valve arrangement of the first subsystem and the flow-control valve arrangement of the second subsystem includes an inlet valve and a discharge valve, the inlet valve and the discharge valve being continuous-control valves configured to be electrically actuated by control signals that, when the control signals are compared with each other by the fault detection device and a deviation from reference data is determined, lead to deactivation of at least one of the release valves or the continuous-control valves that is detected as faulty;
• the steering actuator is a hydraulic synchronous cylinder including a first fluid chamber and a second fluid chamber;
• the first fluid chamber and the second fluid chamber are separated by a piston;
• each of the first fluid chamber and the second fluid chamber is directly connected to an output side of the release valve of the first subsystem and an output side of the release valve of the second subsystem;
• the actuating solenoid devices are for the release valves and the continuous-control valves;
• and
• the electrical signal lines connect the actuating solenoid devices to the fault detection device.

A hydraulic power steering system, comprising:

• a steering actuator;
• a first subsystem including a flow-control valve arrangement including a release valve;
• a second subsystem including a flow-control valve arrangement including a release valve;
• a fault detection device;
• and
• for each of the first subsystem and the second subsystem:
• (i) a hydraulic load tap;
• and
• (ii) a hydraulic supply,
• wherein:
• the first subsystem and the second subsystem are configured to control the steering actuator in opposite steering directions;
• the fault detection device is configured to:
• (i) determine and deactivate a faulty component of the first subsystem or the second subsystem;
• and (ii) cause a fault-free component of the first subsystem or the second subsystem to maintain control of the steering actuator;
• each of the flow-control valve arrangement of the first subsystem and the flow-control valve arrangement of the second subsystem includes an inlet valve and a discharge valve, the inlet valve and the discharge valve being continuous-control valves configured to be electrically actuated by control signals that, when the control signals are compared with each other by the fault detection device and a deviation from reference data is determined, lead to deactivation of at least one of the release valves or the continuous-control valves that is detected as faulty;
• the steering actuator is a hydraulic synchronous cylinder including a first fluid chamber and a second fluid chamber;
• the first fluid chamber and the second fluid chamber are separated by a piston;
• each of the first fluid chamber and the second fluid chamber is directly connected to an output side of the release valve of the first subsystem and an output side of the release valve of the second subsystem;
• the hydraulic load tap is between the inlet valve and the release valve;
• the hydraulic load tap is connected to the hydraulic supply;
• and
• the hydraulic supply is configured to supply the inlet valve with a pressurized fluid.

A hydraulic power steering system, comprising:

• a steering actuator;
• a first subsystem including a flow-control valve arrangement including a release valve;
• a second subsystem including a flow-control valve arrangement including a release valve;
• a fault detection device;
• and
• a position monitor configured to monitor the steering actuator as part of the fault detection device,
• wherein:
• the first subsystem and the second subsystem are configured to control the steering actuator in opposite steering directions;
• the fault detection device is configured to:
• (i) determine and deactivate a faulty component of the first subsystem or the second subsystem;
• and (ii) cause a fault-free component of the first subsystem or the second subsystem to maintain control of the steering actuator;
• each of the flow-control valve arrangement of the first subsystem and the flow-control valve arrangement of the second subsystem includes an inlet valve and a discharge valve, the inlet valve and the discharge valve being continuous-control valves configured to be electrically actuated by control signals that, when the control signals are compared with each other by the fault detection device and a deviation from reference data is determined, lead to deactivation of at least one of the release valves or the continuous-control valves that is detected as faulty;
• the steering actuator is a hydraulic synchronous cylinder including a first fluid chamber and a second fluid chamber;
• the first fluid chamber and the second fluid chamber are separated by a piston;
• and
• each of the first fluid chamber and the second fluid chamber is directly connected to an output side of the release valve of the first subsystem and an output side of the release valve of the second subsystem.

A hydraulic power steering system, comprising:

• a steering actuator;
• a first subsystem including a flow-control valve arrangement including a release valve;
• a second subsystem including a flow-control valve arrangement including a release valve;
• and
• a fault detection device,
• wherein:
• the first subsystem and the second subsystem are configured to control the steering actuator in opposite steering directions;
• the fault detection device is configured to:
• (i) determine and deactivate a faulty component of the first subsystem or the second subsystem;
• and (ii) cause a fault-free component of the first subsystem or the second subsystem to maintain control of the steering actuator;
• each of the flow-control valve arrangement of the first subsystem and the flow-control valve arrangement of the second subsystem includes an inlet valve and a discharge valve, the inlet valve and the discharge valve being continuous-control valves configured to be electrically actuated by control signals that, when the control signals are compared with each other by the fault detection device and a deviation from reference data is determined, lead to deactivation of at least one of the release valves or the continuous-control valves that is detected as faulty;
• the steering actuator is a hydraulic synchronous cylinder including a first fluid chamber and a second fluid chamber;
• the first fluid chamber and the second fluid chamber are separated by a piston;
• each of the first fluid chamber and the second fluid chamber is directly connected to an output side of the release valve of the first subsystem and an output side of the release valve of the second subsystem;
• the first fluid chamber is directly connected to a first port of the release valve of the first subsystem and a first port of the release valve of the second subsystem;
• and
• the second fluid chamber is directly connected to a second port of the release valve of the first subsystem and a second port of the release valve of the second subsystem.