A hydraulic-pump flow-rate calibration system includes: a variable capacitance type hydraulic pump that supplies an operating fluid to a hydraulic actuator; a regulator that changes the dispense flow rate of the hydraulic pump according to a flow rate command signal; a flow rate detection device that detects the flow rate of the operating fluid; a control device that outputs the flow rate command signal to the regulator to control the regulator; and a calibration device that calculates an actual measurement characteristic of the dispense flow rate for the flow rate command signal, and performs, on a preset reference characteristic, calibration based on the actual measurement characteristic. The actual measurement characteristic is calculated as a result of the flow rate of the operating fluid being detected by the flow rate detection device during output of a predetermined flow rate command signal from the control device to the regulator.

The present disclosure relates to a hydraulic circuit comprising: a hydraulic displacement unit for driving an implement; a hydraulic machine fluidly connected or selectively fluidly connected with the hydraulic displacement unit the hydraulic machine having a fixed hydraulic displacement; an electric machine drivingly engaged or selectively drivingly engaged with the hydraulic machine; a hydraulic pump fluidly connected or selectively fluidly connected with the hydraulic displacement unit, the hydraulic pump having a variable hydraulic displacement; and an electric motor drivingly engaged or selectively drivingly engaged with the hydraulic pump.

An object of the present invention is to provide a construction machine capable of suppressing lugging down of an engine irrespective of contents of operation of an operator and the load state of a hydraulic actuator. A controller 50 includes: a demanded torque estimating section 50c configured to estimate demanded torque as torque demanded from an engine 9 by the first hydraulic pump on the basis of a demanded velocity of a first hydraulic actuator 1 and a load pressure on the first hydraulic actuator; a demanded velocity limiting section 50d configured to, in a case in which a demanded torque change rate as a change rate of the demanded torque exceeds a predetermined change rate, limit the demanded velocity such that the demanded torque change rate becomes equal to or lower than the predetermined change rate; and a command calculating section 50e configured to calculate a delivery flow rate of the first hydraulic pump on the basis of the demanded velocity of the first hydraulic actuator, the demanded velocity being limited by the demanded velocity limiting section.

An object of the present invention is to provide a construction machine that has a hydraulic closed-circuit system mounted therein and capable of selectively connecting some of a plurality of hydraulic pumps driven by two engines to any one of a plurality of hydraulic actuators and that can downsize the engines while maintaining high work efficiency. A controller 80 includes an actuator/engine allocation computing section F6 that, at the time of connecting closed-circuit pumps that are not connected to any of the hydraulic actuators 1, 3, 5, and 7 to any one of the hydraulic actuators, allocates closed-circuit pumps driven by a right engine 9b to the one hydraulic actuator in a case in which an estimated maximum load on a left engine 9a is heavier than an estimated maximum load on the right engine, and allocates closed-circuit pumps driven by the left engine to the one hydraulic actuator in a case in which the estimated maximum load on the right engine is heavier than the estimated maximum load on the left engine.

A hydraulic system having a hydraulic pump, having a plurality of hydraulic loads and having a plurality of load-sensing valves for adjusting the pump performance of the hydraulic pump. An association unit is arranged between the hydraulic pump and the hydraulic loads and in a first switched state defines a first hydraulic path between the hydraulic pump and the hydraulic loads and in a second switched state defines a second hydraulic path between the hydraulic pump and the hydraulic loads. The system comprises a controller, which processes a state value of a hydraulic load as an input variable and which determines a control signal for the switched state of the association unit. The invention also relates to a method for controlling a hydraulic system.

An object of the present invention is to provide a construction machine capable of suppressing lugging down of an engine irrespective of contents of operation of an operator and the load state of a hydraulic actuator. A controller 50 includes: a demanded torque estimating section 50c configured to estimate demanded torque as torque demanded from an engine 9 by the first hydraulic pump on the basis of a demanded velocity of a first hydraulic actuator 1 and a load pressure on the first hydraulic actuator; a demanded velocity limiting section 50d configured to, in a case in which a demanded torque change rate as a change rate of the demanded torque exceeds a predetermined change rate, limit the demanded velocity such that the demanded torque change rate becomes equal to or lower than the predetermined change rate; and a command calculating section 50e configured to calculate a delivery flow rate of the first hydraulic pump on the basis of the demanded velocity of the first hydraulic actuator, the demanded velocity being limited by the demanded velocity limiting section.

An object of the present invention is to provide a construction machine that has a hydraulic closed-circuit system mounted therein and capable of selectively connecting some of a plurality of hydraulic pumps driven by two engines to any one of a plurality of hydraulic actuators and that can downsize the engines while maintaining high work efficiency. A controller 80 includes an actuator/engine allocation computing section F6 that, at the time of connecting closed-circuit pumps that are not connected to any of the hydraulic actuators 1, 3, 5, and 7 to any one of the hydraulic actuators, allocates closed-circuit pumps driven by a right engine 9b to the one hydraulic actuator in a case in which an estimated maximum load on a left engine 9a is heavier than an estimated maximum load on the right engine, and allocates closed-circuit pumps driven by the left engine to the one hydraulic actuator in a case in which the estimated maximum load on the right engine is heavier than the estimated maximum load on the left engine.

Manual hydraulic override pumps for use with actuators are described herein. An example apparatus includes a manifold including a reservoir port to be fluidly coupled to a reservoir of fluid, a pump port to be fluidly coupled to a pump, a first actuator port to be fluidly coupled to a first chamber of an actuator, and a second actuator port to be fluidly coupled to a second chamber of the actuator. The example apparatus also includes a rotor disposed in a cavity formed in the manifold. The rotor is rotatable between a first actuating position in which the rotor fluidly couples the first actuator port and the pump port, and a second actuating position in which the rotor fluidly couples the second actuator port and the pump port.

A operator supporting electrohydraulic drive and control system based on, position sensors (8) (9), a electronic control unite ECU (2), a recovery, storing and re-use system for energy, and with actuator (3) (4) and the drive control valve (6) (7) bolted together in one (3+6) (4+7) unite and with the valve (6) (7) independently of the ECU (2) is controlling effective use of pump capacity and recovery of energy and with control of speed for low speeds, or prevented speed by valves (6) (7) or pump (10) (10a) (11) (11a) displacement and for higher speed with control of deplacement of pumps and motors and with valves (6) (7) at the same time controlled to be fully open.

Manual hydraulic override pumps for use with actuators are described herein. An example apparatus includes a manifold including a reservoir port to be fluidly coupled to a reservoir of fluid, a pump port to be fluidly coupled to a pump, a first actuator port to be fluidly coupled to a first chamber of an actuator, and a second actuator port to be fluidly coupled to a second chamber of the actuator. The example apparatus also includes a rotor disposed in a cavity formed in the manifold. The rotor is rotatable between a first actuating position in which the rotor fluidly couples the first actuator port and the pump port, and a second actuating position in which the rotor fluidly couples the second actuator port and the pump port.