An inlet section for use in a hydraulic distributor including a valve body and a slider with a first area and a second area. The inlet section further including said slider being longitudinally slidable within the valve body between a first position in which it prevents passage of fluid from a high pressure line to a low pressure line, and a second position in which it enables passage of fluid. The inlet section further including a main spring active on the second area of the slider in a direction consistent with action of the second pressure and a control device of the slider. The control device of the slider includes a mechanical actuator member selectively active on the slider in a direction consistent with the action of the first pressure on the first area of the slider so as to force the slider in the second position.

Problem to be solved: To provide a hydraulic circuit for the construction machine which enables to use the relief valve of low capacity in the work tool circuit. Solution: The hydraulic circuit 2 for a construction machine has: a hydraulic pump 4 of variable capacity, a work tool 6 operated by hydraulic oil delivered by the hydraulic pump 4, a work tool operating device 10 to output a signal for operating the work tool 6, a control valve 14 allowing the hydraulic pump 4 to supply the hydraulic oil to the work tool 6 based on the signal output from the work tool operating device 10, a tool's relief valve 44 to release the hydraulic oil flowing between the control valve 14 and the work tool 6, a pressure sensor 46 to detect a pressure of hydraulic oil flowing into the work tool 6, and a controller 48 to reduce a delivery rate from the hydraulic pump 4 when the pressure detected by the pressure sensor 46 exceeds a predetermined value.

An electro-hydraulic actuator includes: a motor output rotative power; an external gear pump activated by the motor; a hydraulic actuator operated by a pressurized working fluid supplied by the external gear pump; a manifold block in which a flow channel forming a working fluid circuit of the hydraulic actuator is incorporated; a first portion to store the motor; a second portion to store the external gear pump, the hydraulic actuator, and a reservoir; and a coupling portion to couple the first portion and the second portion in a liquid-tight state. The coupling portion includes a communication hole through which the first portion and the second portion communicate, a rotational shaft of the motor and a driving shaft of the external gear pump are joined to each other, and the external gear pump is attached to the coupling portion while being stored in the manifold block.

A hydraulic system for controlling an implement on a work machine may include a hydraulic reservoir, a hydraulic pump in fluid communication with the reservoir, a central valve in fluid communication with the pump and configured for controlling the implement, a pressure relief system arranged in fluid communication with the hydraulic pump and the central valve, and a controller. The controller may be configured for controlling the hydraulic pump, the central valve and the pressure relief system and selecting between operating the hydraulic system at a first pressure and a second pressure based on a factor relating to implement position.

A working machine includes a machine body, a first hydraulic actuator mounted on the machine body, a first control valve that controls the first hydraulic actuator, a controller that controls the first control valve, and a second hydraulic actuator that is different from the first hydraulic actuator. When the second hydraulic actuator and the first hydraulic actuator are operated in combination, the controller reduces the amount of change in the flow rate of a hydraulic fluid supplied from the first control valve to the first hydraulic actuator with respect to changes in a manipulation amount to operate the first hydraulic actuator to a value smaller than that when the first hydraulic actuator is solely operated.

A work machine comprises: a work implement; a hydraulic cylinder; a hydraulic pump that supplies the hydraulic oil to the hydraulic cylinder via a hydraulic circuit; a relief valve that can set a relief pressure of the hydraulic circuit to either a first set pressure or a second set pressure higher than the first set pressure; a detection unit that detects at least one of a pressure of the hydraulic oil in the hydraulic circuit and a speed of the work implement; and a relief pressure changing unit that changes a relief pressure of the relief valve from the first set pressure to the second set pressure based on a detection value of at least one of the pressure of the hydraulic oil in the hydraulic circuit and the speed of the work implement when the controlled state of the work implement is the excavation state.

A hydraulic system of a construction machine includes: control valves interposed between a main pump and hydraulic actuators; and first solenoid proportional valves connected to pilot ports of the control valves. The hydraulic system further includes: an unloading valve including a pilot port; and a second solenoid proportional valve connected to the pilot port of the unloading valve by a secondary pressure line and connected to an auxiliary pump by a primary pressure line. A switching valve including a pilot port connected to the secondary pressure line by a pilot line is interposed between the auxiliary pump and the first solenoid proportional valves.

An arrangement for a utility vehicle includes at least one air dryer unit and a regulating unit, wherein the air dryer unit and the regulating unit are designed in each case as separate units. The air dryer unit has at least one air dryer module, in particular an air dryer cartridge, at least one discharge valve and at least one control line for the pneumatic control of the discharge valve. At least one connecting line is provided in the air dryer unit with connection to the air dryer module. The connecting line leads directly to a consumer non-return valve for the air dryer unit, which is arranged outside of the air dryer unit, wherein the connecting line can be used at least partially bi-directionally and/or can be or is connected to a bi-directionally usable line section.

A power control system for a forestry machine may include an engine control module and a pump control module. The engine control module may be configured to control an engine speed of an engine of the forestry machine. The engine speed may be limited in accordance with a maximum engine speed. The pump control module may determine whether a first function of the forestry machine is activated, determine whether a sensed pressure of a pump associated with the first function is greater than or equal to a high pressure setpoint, and output a control signal indicating a request for a power increase in response to determining that the first function is activated and the sensed pressure is greater than or equal to the high pressure setpoint. The engine control module may increase the maximum engine speed in response to the request for the power increase from the pump control module.

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.