Abstract: A hydraulic system for a felling saw head includes a hydraulic motor, operatively coupled to a saw disc of the saw head, a hydraulic variable displacement pump, operatively coupled to the hydraulic motor to supply pressurized fluid to the motor, and a controller configured to control the pump. To provide a target operating speed of the saw disc, the motor is configured to operate at a first displacement corresponding to a first flow rate of hydraulic fluid through the motor During at least a part of a saw recovery operation, the controller controls the pump to operate at a current pump displacement that results in a flow rate of hydraulic fluid through the pump that exceeds the first flow rate through the motor. Saw recovery time may be reduced without overspeeding the saw by including a metered flow control device between the pump and the motor.

Abstract: An electronic begin of regulation (EBOR) control system and method is disclosed for a hydraulic motor of a machine having an engine for producing power and a track system for moving. The EBOR system includes a flow source, variable displacement motor, pressure sensor and control unit. The operator sets a pressure setpoint. The flow source generates flow in a loop with the motor. The pressure sensor senses loop working pressure. The control unit adjusts motor displacement based on comparisons between the pressure setpoint and sensed loop working pressure. The flow source can be bidirectional, and different pressure sensors can be used depending on the direction. The pressure setpoint can be varied during operation, and the control unit can adjust the displacement of the motor based on comparisons between the latest pressure setpoint and the loop working pressure sensed by the appropriate pressure sensor.

Abstract: An electronic begin of regulation (EBOR) control system and method is disclosed for a hydraulic motor of a machine having an engine for producing power and a track system for moving. The EBOR system includes a flow source, variable displacement motor, pressure sensor and control unit. The operator sets a pressure setpoint. The flow source generates flow in a loop with the motor. The pressure sensor senses loop working pressure. The control unit adjusts motor displacement based on comparisons between the pressure setpoint and sensed loop working pressure. The flow source can be bidirectional, and different pressure sensors can be used depending on the direction. The pressure setpoint can be varied during operation, and the control unit can adjust the displacement of the motor based on comparisons between the latest pressure setpoint and the loop working pressure sensed by the appropriate pressure sensor.

Abstract: The present disclosure provides a control system of a powered machine. The control system includes a hydraulic motor configured to drive a track system of the machine. The motor is operable with a variable displacement. A control valve is fluidly coupled to the motor. In addition, the control system includes a controller and an electro-hydraulic valve disposed in electrical communication with the controller and fluid communication with the control valve. The electro-hydraulic valve receives a signal from the controller, and based on the signal, the electro-hydraulic valve hydraulically varies the start of control pressure of the motor.

Abstract: A hydraulic system for a felling saw head includes a hydraulic motor, operatively coupled to a saw disc of the saw head, a hydraulic variable displacement pump, operatively coupled to the hydraulic motor to supply pressurized fluid to the motor, and a controller configured to control the pump. To provide a target operating speed of the saw disc, the motor is configured to operate at a first displacement corresponding to a first flow rate of hydraulic fluid through the motor During at least a part of a saw recovery operation, the controller controls the pump to operate at a current pump displacement that results in a flow rate of hydraulic fluid through the pump that exceeds the first flow rate through the motor. Saw recovery time may be reduced without overspeeding the saw by including a metered flow control device between the pump and the motor.

Abstract: A pressurized fluid subassembly comprising: (a) a fluid driven actuator configured to utilize fluid at a high pressure to change an overall length of the fluid driven actuator; and, (b) a sequence valve interposing a low pressure line and a supply line conveying the fluid to the fluid driven actuator, the sequence valve including a first sequence configured to inhibit fluid communication between the supply line and the low pressure line when the fluid at the high pressure is actively supplied to the fluid driven actuator, the sequence valve including a second sequence configured to establish fluid communication between the supply line and the low pressure line when the fluid at the high pressure is not actively supplied to the fluid driven actuator, wherein the sequence valve includes a variable bias that changes depending upon whether the fluid at the high pressure is actively supplied to the fluid driven actuator.

Abstract: The present disclosure provides a control system of a powered machine. The control system includes a hydraulic motor configured to drive a track system of the machine. The motor is operable with a variable displacement. A control valve is fluidly coupled to the motor. In addition, the control system includes a controller and an electro-hydraulic valve disposed in electrical communication with the controller and fluid communication with the control valve. The electro-hydraulic valve receives a signal from the controller, and based on the signal, the electro-hydraulic valve hydraulically varies the start of control pressure of the motor.

Abstract: An articulated dump truck is provided with an electro-hydraulic bin control system including a proportional control valve for the bin lift cylinders and including a solenoid-operated regenerative valve assembly mounted adjacent the lift cylinders and being actuated, during lifting the bin for dumping a load of material from the bin, to cause a regenerative flow to occur when the force required by the bin lift cylinders to continue lifting the bin falls to a predetermined force. The force required for tilting the bin is continuously calculated by an electronic control unit taking into account a sensed bin load, a sensed bin tip amount and a sensed side-to-side inclination of the bin. In a simplified second embodiment, the proportional control valve controls the regenerative flow.

Abstract: A pressurized fluid subassembly comprising: (a) a fluid driven actuator configured to utilize fluid at a high pressure to change an overall length of the fluid driven actuator; and, (b) a sequence valve interposing a low pressure line and a supply line conveying the fluid to the fluid driven actuator, the sequence valve including a first sequence configured to inhibit fluid communication between the supply line and the low pressure line when the fluid at the high pressure is actively supplied to the fluid driven actuator, the sequence valve including a second sequence configured to establish fluid communication between the supply line and the low pressure line when the fluid at the high pressure is not actively supplied to the fluid driven actuator, wherein the sequence valve includes a variable bias that changes depending upon whether the fluid at the high pressure is actively supplied to the fluid driven actuator.

Abstract: A hydraulic filtering, cooling and lubrication system is disclosed. The system is for use with a vehicle including an engine, a pump coupled to the engine and a plurality of axles. The system includes a separate manifold for each axle of the vehicle and/or each pair of wet disc brakes. Each manifold is separate from every other manifold to minimize cross contamination of axles.

Abstract: An articulated dump truck is provided with an electro-hydraulic bin control system including a proportional control valve for the bin lift cylinders and including a solenoid-operated regenerative valve assembly mounted adjacent the lift cylinders and being actuated, during lifting the bin for dumping a load of material from the bin, to cause a regenerative flow to occur when the force required by the bin lift cylinders to continue lifting the bin falls to a predetermined force. The force required for tilting the bin is continuously calculated by an electronic control unit taking into account a sensed bin load, a sensed bin tip amount and a sensed side-to-side inclination of the bin.