Abstract:
A port plate for a swashplate type axial piston pump is described herein. The port plate includes an inlet port, a discharge port, and a first metering notch in fluidic communication via a first passage with a metering notch area adjustment valve configured to adjust the effective area of the metering notch. The first metering notch is disposed at a leading edge of one of the inlet port or the discharge port.
Abstract:
A hydraulic control system for a machine is disclosed. The hydraulic control system may include a pump configured to pressurize fluid, a displacement control valve configured to affect displacement of the pump, and a solenoid configured to bias the displacement control valve to a zero position. The hydraulic control system may also include a controller in communication with the solenoid. The controller may be configured to estimate a bias current that biases the displacement control valve to the zero position, and to control the displacement control valve based on the bias current. The controller also be further configured to monitor a pump parameter of the pump, and to determine a control error associated with the pump parameter. The controller may further be configured to selectively adjust the bias current based on the control error.
Abstract:
A port plate for a swashplate type axial piston pump is described herein. The port plate includes an inlet port, a discharge port, and a first metering notch in fluidic communication via a first passage with a metering notch area adjustment valve configured to adjust the effective area of the metering notch. The first metering notch is disposed at a leading edge of one of the inlet port or the discharge port.
Abstract:
A system for determining an estimated output from a variable displacement hydraulic pump includes a prime mover, and torque, pressure, and displacement sensors. A controller determines the output torque from the prime mover, determines an input torque to the variable displacement hydraulic pump based upon the output torque, determines an output from one of the pressure sensor and the displacement sensor, and determines an inertia torque loss based upon the angular acceleration of the prime mover. The controller further determines a failure of another of the pressure sensor and the displacement sensor and determines an estimated output from the another of the pressure sensor and the displacement sensor based upon the input torque to the variable displacement hydraulic pump, the output from the one of the pressure sensor and the displacement sensor, and the inertia torque loss.
Abstract:
A system for determining an estimated displacement of a variable displacement hydraulic pump includes a control cylinder associated with the swash plate of the variable displacement hydraulic pump to control the angle of inclination of the swash plate and a valve that controls the flow of hydraulic fluid to the control cylinder and has a position that defines an effective area of an opening of the valve. A pressure sensor generates pressure signals indicative of an output pressure from the variable displacement hydraulic pump. A controller is configured to receive pressure signals from the pressure sensor and determine an estimated displacement of the variable displacement hydraulic pump based upon the pressure signals from the pressure sensor and the position of the valve.
Abstract:
A system for determining an estimated output from a variable displacement hydraulic pump includes a prime mover, a torque sensor, a pressure sensor, and a displacement sensor. A controller is configured to determine the output torque from the prime mover, determine an input torque to the variable displacement hydraulic pump based upon the output torque, determine an output from one of the pressure sensor and the displacement sensor based upon the signals. The controller is further configured to determine a failure of another of the pressure sensor and the displacement sensor and determine an estimated output from the another of the pressure sensor and the displacement sensor based upon the input torque to the variable displacement hydraulic pump and the output from the one of the pressure sensor and the displacement sensor.
Abstract:
A system for determining an estimated displacement of a variable displacement hydraulic pump includes a control cylinder associated with the swash plate of the variable displacement hydraulic pump to control the angle of inclination of the swash plate and a valve that controls the flow of hydraulic fluid to the control cylinder and has a position that defines an effective area of an opening of the valve. A pressure sensor generates pressure signals indicative of an output pressure from the variable displacement hydraulic pump. A controller is configured to receive pressure signals from the pressure sensor and determine an estimated displacement of the variable displacement hydraulic pump based upon the pressure signals from the pressure sensor and the position of the valve.
Abstract:
A ride control system includes four independent metering valves (IMVs) that are independently and selectively controlled by a controller for attenuating oscillations in a hydraulic actuator of a machine. The controller is configured to open at least one of the IMVs for supplying pressurized fluid from a tank to a head end chamber of the hydraulic actuator when a pressure of the head end chamber drops to a value less than an initially registered pressure. Additionally, when the displacement of the piston block is positive and the pressure in the head end chamber falls to a value less than the pressure of fluid in a rod end chamber of the hydraulic actuator, the controller may also open another one of the IMVs by which fluid from the rod end chamber could be supplied to the head end chamber for supplementing pump flow and attenuating oscillations in the hydraulic actuator.
Abstract:
An energy recovery system includes cylinders that articulate a hydraulic tool in a pump mode to provide potential energy and in a motor mode to recover the potential energy. The energy recovery system includes a tank that stores a hydraulic fluid for the cylinders and an open circuit variable displacement pump that circulates the hydraulic fluid in the pump mode from the tank to the cylinders and in the motor mode from the cylinders to the tank. The open circuit variable displacement pump includes a swashplate articulable between a positive position and a negative position. In the positive position, the hydraulic fluid circulates in the pump mode and in the negative position the hydraulic fluid circulates in the motor mode. The open circuit variable displacement pump includes an actuator that articulates the swashplate and a bias system that maintains the swashplate in a positive position when the hydraulic fluid is not in circulation.
Abstract:
A ride control system includes four independent metering valves (IMVs) that are independently and selectively controlled by a controller for attenuating oscillations in a hydraulic actuator of a machine. The controller is configured to open at least one of the IMVs for supplying pressurized fluid from a tank to a head end chamber of the hydraulic actuator when a pressure of the head end chamber drops to a value less than an initially registered pressure. Additionally, when the displacement of the piston block is positive and the pressure in the head end chamber falls to a value less than the pressure of fluid in a rod end chamber of the hydraulic actuator, the controller may also open another one of the IMVs by which fluid from the rod end chamber could be supplied to the head end chamber for supplementing pump flow and attenuating oscillations in the hydraulic actuator.