Abstract: A steering system for a machine is disclosed. The steering system may include a first pilot system including a first pilot source and a first set of electrohydraulic valves, and a second pilot system including a second pilot source and a second set of electrohydraulic valves. The first pilot system and the second pilot system may be configured to move the steering valve via pilot flow of the hydraulic fluid. The steering system may further include an electrohydraulic selector valve configured to regulate pilot flow to the first set of electrohydraulic valves and the second set of electrohydraulic valves. The electrohydraulic selector valve may be a two-position, five-way valve.

Abstract: A steering system for a machine is disclosed. The steering system may include a first pilot system including a first pilot source and a first set of electrohydraulic valves, and a second pilot system including a second pilot source and a second set of electrohydraulic valves. The first pilot system and the second pilot system may be configured to move the steering valve via pilot flow of the hydraulic fluid. The steering system may further include an electrohydraulic selector valve configured to regulate pilot flow to the first set of electrohydraulic valves and the second set of electrohydraulic valves. The electrohydraulic selector valve may be a two-position, five-way valve.

Abstract: A hydraulic motor drive system is disclosed. The hydraulic motor drive system includes a pump, a flow control module fluidly coupled to a discharge of the pump via a first conduit, and a hydraulic motor fluidly coupled to the flow control module via a second conduit and a third conduit, and a controller operatively coupled to the flow control module. The controller is configured to operate the flow control module in a first mode, such that the flow control module blocks fluid communication between the pump and the hydraulic motor via the second conduit, and effects fluid communication between the pump and the hydraulic motor via the third conduit, and operate the flow control module in a second mode, such that the flow control module effects fluid communication between the pump and the hydraulic motor via the second conduit.

Abstract: A machine includes a hydraulic fan system for circulating cooling air through an engine compartment. Periodically, the fan rotation direction is briefly reversed in order to dislodge any material debris that may have accumulated at the inlet to the engine compartment. When a fan reversal event is initiated, the fan motor will continue to rotate due to angular momentum even after the pump output flow has been switched from a first motor port to a second motor port. During this continued rotation as the fan decelerates to zero speed, vacuum pressure levels can arise at the first motor port, and a pressure spike can develop at the second motor port. In order to alleviate these conditions, a pressure transfer valve briefly opens to facilitate fluid flow directly from the second motor port to the first motor port as the fan motor decelerates towards zero speed before reversing direction, simultaneously alleviating vacuum and pressure spike conditions.

Abstract: A machine includes a hydraulic fan system for circulating cooling air through an engine compartment. Periodically, the fan rotation direction is briefly reversed in order to dislodge any material debris that may have accumulated at the inlet to the engine compartment. When a fan reversal event is initiated, the fan motor will continue to rotate due to angular momentum even after the pump output flow has been switched from a first motor port to a second motor port. During this continued rotation as the fan decelerates to zero speed, vacuum pressure levels can arise at the first motor port, and a pressure spike can develop at the second motor port. In order to alleviate these conditions, a pressure transfer valve briefly opens to facilitate fluid flow directly from the second motor port to the first motor port as the fan motor decelerates towards zero speed before reversing direction, simultaneously alleviating vacuum and pressure spike conditions.

Abstract: A hydraulic system is disclosed. The hydraulic system includes a source of pressurized fluid and a plurality of fluid actuators configured to affect an amount of resistive torque applied to an associated traction device. The hydraulic system also includes a plurality of valves each configured to selectively communicate pressurized fluid to one of the plurality of fluid actuators. The hydraulic system further includes a controller configured to control the plurality of valves as a function of at least a steering command.

Abstract: A hydraulic system for a work machine having a power source is disclosed. The hydraulic system has a tank configured to hold a supply of fluid and a source configured to pressurize the fluid. The hydraulic system also has a brake mechanism in fluid communication with the source to receive pressurized fluid and a power source cooling fan in fluid communication with the source to receive pressurized fluid. The hydraulic system further has a load-sensing valve in fluid communication with the source to control an output of the source in response to a load on the brake mechanism and a load on the power source cooling fan.