A hydraulic machine. A boom actuator includes a large chamber and a small chamber. A recovery unit receives fluid discharged from the large chamber and then recovers energy. A recovery line connects the large chamber and the recovery unit. An accumulator is connected to a first point on the recovery line. A discharge valve is disposed on the recovery line between the first point and the recovery unit. A first sensor measures a pressure in the accumulator. A controller controls opening and closing of the discharge valve. The controller performs anti-bouncing control of: determining a target pressure in the accumulator corresponding to a load pressure applied to fluid in the large chamber by a load according to a predetermined correspondence; and controlling the opening and closing of the discharge valve such that the pressure in the accumulator measured by the first sensor reaches the target pressure.

The disclosure relates to a method for damping a movably mounted attachment part of a machine, wherein the attachment part is movable by means of a hydraulic cylinder, wherein the hydraulic cylinder is actuated via a hydraulic pump, comprising: receiving a measured value of a pressure (P) in a load-side chamber of the hydraulic cylinder during a measurement phase, and controlling the hydraulic pump to adjust the pressure in the load-side chamber of the hydraulic cylinder to the measured value as a setpoint value during operation of the machine for damping the movably mounted attachment part.

A construction machine including a variable displacement pump, and a boom cylinder including a rod operable to extend and retract to move a boom of the construction machine. A first chamber of the boom cylinder is configured to be supplied with fluid from the pump during rod extension while fluid is removed from a second chamber of the boom cylinder. The second chamber of the boom cylinder is configured to be supplied with fluid from the pump during rod retraction while fluid is removed from the first chamber of the boom cylinder. The construction machine has an active ride control mode in which a valve between the boom cylinder and the pump remains open, and the pump is configured to actively damp pressure fluctuations in the boom cylinder by variation of a displacement setting.

A motor grader having ride control for dampening machine bounce using a DCM assembly rotatably coupled to and suspended from a frame of the motor grader is disclosed. Each lift cylinder for the DCM may have an associated ride control circuit with an accumulator, a ride control conduit fluidly connected to a carry end of the lift cylinder and having a flow restriction element, and a ride control accumulator valve fluidly connected to the accumulator and the ride control conduit and operable to either block or allow fluid communication between the carry end and the accumulator through the flow restriction element. Each rid control circuit may also include a head end valve fluidly connected to between the head end of the lift cylinder and a low pressure fluid reservoir and operable to block or allow fluid communication between the head end and the low pressure fluid reservoir.

A shovel includes a hydraulic actuator, an operating apparatus used to operate the hydraulic actuator, an obtaining device configured to obtain information concerning the vibration of the body of a shovel, and a hardware processor. The hardware processor is configured to perform such control as to reduce the responsiveness of the hydraulic actuator to the operation of the operating apparatus when the body of the shovel is vibrating or the vibration is likely to occur in the body of the shovel, based on the output of the obtaining device.

A ride control valve includes a valve housing (30) having a main spool (32) longitudinally displaceably arranged in the valve housing, a balance spool (34), and fluid passage points for a pressure supply (P), a tank return line (T), an accumulator (14) and a boom cylinder unit (10). The balance spool (34) continuously balances the pressure between the fluid ports of the accumulator (14) and the boom cylinder unit (10). The main spool (32) is controlled by the operator and initially interconnects these fluid ports of the accumulator (14) and the boom cylinder unit (10), starting from a closed fluid connection, via a restricted fluid connection, to a fully opened fluid connection, or disconnects them from each other in reverse sequence.

An arrangement for triggering an actuator for adjusting an adjustable element of an agricultural working machine comprises: a specifying device for generating adjustment commands for the adjustable element; a control arrangement for the actuator; and a signal-shaping unit which, upon receipt of an adjustment command, initially applies a first signal dependent on the adjustment command to the control arrangement, and then applies a second signal, which is dependent on the adjustment command and delayed in time relative to the first signal, the second signal leading to a reduction or cancellation of a natural oscillation generated by the first signal in the system consisting of working machine and element.

A mobile hydraulic system includes a hydraulic actuator coupled to a load, and a control unit coupled to the load and/or to the hydraulic actuator. The control unit is adapted to anticipate an over-center transition of the load relative to a gravity vector prior to the over-center transition through the use of sensors configured with accelerometers, gyroscopes and magnetometers. In some examples, the over-center transition is from an overrunning driving of the load to a passive driving of the load. In some examples, the over-center transition is from a passive driving of the load to an overrunning driving of the load. In some examples, the control unit is adapted to control change in a metered flow through one or more ports of the associated actuator to minimize and/or prevent one or more hydraulic effects of the anticipated over-center transition. In some examples, the control unit controls the metered flow by causing one or more actuators (e.g., a solenoid) to shift one or more valve positions to change the flow through one or more ports of the associated actuator.

A work vehicle includes an arm. An arm cylinder drives the arm. A direction control valve operates the arm cylinder by allowing supply of a hydraulic oil to the arm cylinder as a spool moves. An oil path is connected to the direction control valve. A pilot oil for moving the spool flows through the oil path. A proportional solenoid valve for arm excavation is provided in the oil path. An arm control member is provided for an operator to operate drive of the arm. An amount of operation of the arm control member is equal to or smaller than a prescribed value in a first operation state and greater than the prescribed value in a second operation state. A command current instructing an opening of the proportional solenoid valve for arm excavation is set to a constant value in the first operation state.

A method of operating a ride control system of a machine having an accumulator is provided. The method includes detecting a pressure at the accumulator. The method includes generating a first set of input data associated with a drive system and a brake pedal. The method includes generating a second set of input data associated with a lift cylinder. The method also includes determining a working mode of the ride control system based on the first set of input data and the second set of input data. The working mode of the ride control system includes a normal mode and an exposed mode. The method includes operating a ride control activation solenoid valve, upon determining the pressure at the accumulator to be above a predefined threshold, and the working mode of the ride control system to be the exposed mode.