The invention relates to a construction machine, road milling machine, stabiliser, recycler, surface miner, and a to method for controlling a construction machine. The construction machine has a machine frame 2 supported by a chassis 1 and a plurality of hydraulic systems 15, 16, each of which has at least one hydraulic component 18, 22, at least one hydraulic pump 17, 21 for conveying hydraulic fluid for the at least one hydraulic component and at least one hydraulic line 28, 31 for transporting the hydraulic fluid from the at least one hydraulic pump to the at least one hydraulic component. The drive device of the construction machine comprises at least one internal combustion engine 24. A power transmission device 44 is provided for transmitting at least part of the drive power from the internal combustion engine 24 to the hydraulic pumps 17, 21. The construction machine according to the invention is characterised by a hydraulic control device 26, which is assigned to two hydraulic systems 15, 16 of the plurality of hydraulic systems. The hydraulic control device 16 is designed such that, in a special operating mode, at least part of the hydraulic fluid delivered by the hydraulic pump 17 of the one hydraulic system 15 is supplied to the other hydraulic system 16.

A hydraulic system for a working machine, the hydraulic system includes: a hydraulic fluid reservoir; a boom actuator having an ascending chamber and a descending chamber; a first pump; a first directional control valve comprising a first ascending state configured for moving the boom in the ascending direction, a descending state configured for moving the boom actuator in the descending direction, and a first neutral state; a second pump; a second directional control valve comprising a second ascending state configured for moving the boom actuator in the ascending direction, and a second neutral state; wherein the second directional control valve further comprises a float state configured to connect at least one of the ascending and descending chambers to the hydraulic reservoir for permitting the boom to move freely in the descending and/or descending directions.

A pressurizing device includes: a pressurizing unit that pressurizes a pressurized object by supplying a working fluid; a first cylinder mechanism that supplies the working fluid in a first cylinder to the pressurizing unit by output of a first drive source; a second cylinder mechanism that supplies the working fluid in a second cylinder to the pressurizing unit by output of a second drive source; and a control device that controls the first drive source and the second drive source, in which the control device performs transition control to transition to a second supply state of supplying the working fluid from the second cylinder mechanism to the pressurizing unit when satisfying a remaining amount condition of the working fluid in the first cylinder of the first cylinder mechanism in a first supply state of supplying the working fluid from the first cylinder mechanism to the pressurizing unit.

Provided is a work machine which can achieve both of excellent operability when an operator manually operates a machine body or a work device and an accuracy of control of the machine body or the work device when a controller performs automatic control. The controller is configured to, in a case where the automatic control function selector switch gives an instruction to disable the automatic control function, adjust an opening amount of a bleed-off valve to a maximum opening amount or an opening amount corresponding to input amounts of control levers, and in a case where the automatic control function selector switch gives the instruction to enable the automatic control function, adjust the opening amount of the bleed-off valve, in at least part of an operation region of the control levers, so as to be smaller than the opening amount with the instruction to disable the automatic control function being given.

Provided is a work machine which can increase the operation speed of an actuator by a regeneration function while securing the position control accuracy of the actuator. A controller is configured to calculate a regeneration flow rate on the basis of an input amount of an operation lever and a target actuator flow rate, subtract the regeneration flow rate from the target actuator flow rate to calculate a target actuator supply flow rate, calculate a target flow rate control valve opening amount on the basis of the target actuator supply flow rate, calculate a target pump flow rate that is equal to or higher than a total target actuator supply flow rate, control a selector valve on the basis of the input amount of the operation lever, control a flow rate control valve according to the target flow rate control valve opening amount, and control a hydraulic pump according to the target pump flow rate.

An object of the present invention is to provide a construction machine that can use the return oil from a hydraulic actuator effectively. For this purpose, a controller computes a flow rate of the return oil from a first hydraulic actuator on the basis of an operation signal from a first operation device, computes a flow rate of oil to be supplied to a second hydraulic actuator on the basis of an operation signal from a second operation device, sets smaller one of the flow rate of the return oil and the flow rate of the oil to be supplied, as a regeneration flow rate that is a flow rate of oil to be regenerated in the second hydraulic actuator, sets a flow rate obtained by subtracting the regeneration flow rate from the flow rate of the return oil, as a recovery flow rate that is a flow rate of oil to be recovered to a pressure accumulating device, adjusts an opening degree of a first control valve 2 such that a flow rate of oil supplied from the first hydraulic actuator to the pressure accumulating device coincides with the recovery flow rate, and adjusts an opening degree of a second control valve such that a flow rate of oil supplied from the first hydraulic actuator to the second hydraulic actuator coincides with the regeneration flow rate.

The present disclosure relates to a hydraulic-electric coupling driven multi-actuator system and control method, and belongs to technical fields of hydraulic transmission and electro-mechanical transmission. The hydraulic-electric coupling driven multi-actuator system comprises one or more hydraulic-electric hybrid driven actuators, first inverters, control valves, centralized hydraulic units and control units, wherein the number of the first inverters and the number of the control valves are the same as that of the hydraulic-electric hybrid driven actuators; each hydraulic-electric hybrid driven actuator is correspondingly connected with one first inverter and one control valve; the centralized hydraulic units are connected with the control valves and configured to supply oil for the hydraulic-electric hybrid driven actuators and to perform power compensation; and the control units are respectively connected with the hydraulic-electric hybrid driven actuators, and each control unit is configured to control output torque of a first motor of the corresponding hydraulic-electric hybrid driven actuator based on pressure information of the hydraulic-electric hybrid driven actuator, such that pressure of driving cavities of the hydraulic-electric hybrid driven actuators is equal, which greatly reduces throttling loss caused by the load differences of the actuators.

A hydraulic system according to one aspect of the present disclosure includes: control valves interposed between a main pump and hydraulic actuators; and solenoid proportional valves connected to pilot ports of the control valves. Among the solenoid proportional valves, a first solenoid proportional valve and a second solenoid proportional valve are connected to a pair of pilot ports of a particular control valve, respectively. The first solenoid proportional valve and the second solenoid proportional valve are directly connected to an auxiliary pump. The solenoid proportional valves except the first solenoid proportional valve and the second solenoid proportional valve are connected to the auxiliary pump via a switching valve. The switching valve includes a pilot port that is connected, by a switching pilot line, to a first pilot line between the first solenoid proportional valve and the particular control valve.

A hydraulic system of a work machine includes a first hydraulic device to operate in a first operation mode while pressure of hydraulic oil supplied from a hydraulic pump via a first oil passage is equal to or higher than a first pressure threshold. The hydraulic oil in the first oil passage is to be discharged via a second oil passage. A pilot check valve is provided in the second oil passage and has a pilot port to receive a pilot pressure of the hydraulic oil. The pilot check valve is closed to stop discharging the hydraulic oil in the first oil passage through the second oil passage while the pilot pressure is lower than the fourth pressure threshold. The pilot check valve is opened while the pilot pressure is higher than or equal to the fourth pressure threshold. The first hydraulic device is a ride control device.

A telescopic actuator includes a first segment having a first hollow cavity, a second segment having a second hollow cavity, a third segment having a third hollow cavity, and a first port and a second port. The second segment is slidably connected to the first segment through the first hollow cavity, and the third segment is slidably connected to the second segment through the second hollow cavity, the second hollow cavity being insulated from the first hollow cavity and communicating with the third hollow cavity. The first port is configured to flow fluid into and out of the first hollow cavity, and the second port is configured to flow fluid into and out of the second hollow cavity and the third hollow cavity. Embodiments described herein also include a motion simulating apparatus and an actuating system incorporating the telescopic actuator.