Abstract: An articulated work machine is steered via left and right hydraulic cylinders that swivel a front portion of a work machine relative to a back portion about a vertical articulation axis. When a low force turn is being performed, high pressure is supplied to only one of the left and right hydraulic cylinders. When a high force turn is performed, high pressure is supplied to one of the left and right hydraulic cylinders, and pressurized hydraulic fluid is also supplied to the other of the left and right hydraulic cylinders in proportion to the torque required for the turn. This strategy allows for excess pressurized fluid, which is not used for the steering purpose, to be utilized by hydraulic implements of the work machine to increase performance capabilities while the machine is being steered in low force mode under light steering load.

Abstract: A hydraulic system for a machine having a work tool is disclosed. The hydraulic system has a tank configured to hold a supply of fluid, and a source configured to pressurize the fluid from the tank. The hydraulic system also has a first hydraulic actuator configured to receive pressurized fluid from the source and effect movement of the work tool, and a second hydraulic actuator configured to receive pressurized fluid from the source and effect steering of the machine. The hydraulic system additionally has at least one operator interface device configured to receive pressurized fluid from the source and selectively meter the pressurized fluid to a control valve to effect movement of the control valve.

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 method of operating an electrically propelled work machine includes the steps of, operating an electrical power source for the work machine, and limiting an output torque of an electrical propulsion motor system of the work machine based upon the occurrence of a crowd force condition of the work machine. An electrically propelled work machine is further provided, including an electronic controller having means for limiting motor output torque based at least in part on a crowd force condition of the work machine.

Abstract: An electro-hydraulic system for a machine may include a brake charging system including at least one accumulator. A fan drive system may include a fan and a fan motor. A fluid source may be in communication with the brake charging system and the fan drive system. The fluid source may be configured to provide pressurized fluid to the brake charging system and the fan drive system to charge at least one accumulator and to drive a fan motor. A priority valve may be configured to provide pressure from the fluid source to the brake charging system, such that the fluid pressure at the accumulator is maintained at a substantially constant level during normal operating conditions.

Abstract: A hydraulic steering system for a work machine may include a first steering actuator having a first and a second chamber. In addition, the steering system may include a second steering actuator having a third and a fourth chamber. A multi-position directional valve may include at least one low power position and at least one high power position. The low power position may be configured to direct fluid only to the first chamber during a low power turn to extend the first steering actuator. The high power position may be configured to direct fluid to the first chamber and the third chamber during a high power turn to retract the second steering actuator.

Abstract: An electro-hydraulic steering control system for directing fluid to steering actuators on a work machine may include a main valve configured to control fluid flow to the steering actuators. Left and right primary steering valves may be in communication with and configured to affect the main valve to control fluid flow to the steering actuators. Left and right redundant steering valves may be in communication with and configured to affect the main valve to control fluid flow to the steering actuators. A shuttle valve may be operably disposed between one of the right primary and the right redundant steering valves and the left primary and left redundant steering valves. The shuttle valve may be operable to selectively control fluid from the one of the right primary and the right redundant steering valves and the left primary and left redundant steering valves to the main valve to control the main valve.