A hybrid work machine has an engine, an assist motor, a hydraulic pump which is driven by the total torque of the engine and the assist motor, and an electric storage device which accumulates electric power generated by the assist motor and supplies the electric power when the assist motor performs electric discharge. The continuous electric discharge from the electric storage device due to continuous operation at high load pressure can be suppressed without an operator experiencing an unusual operational characteristic. To this end, a pump flow rate correction control unit judges whether each hydraulic pump is in a high load operation state or not based on the output horsepower and/or the delivery pressure of each hydraulic pump and performs control such that the delivery flow rate gradually decreases when the hydraulic pump is in the high load operation state and this state continues beyond a predetermined time.

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.

A fluid circuit includes a pressure fluid source, a switching valve, and a cylinder device having first and second chambers and partitioned by a piston. A first accumulator is configured to communicate with the second chamber when pressure fluid is supplied to the first chamber and to accumulate part of the pressure fluid from the second chamber. A pressure booster is connected in hydraulically parallel to the first accumulator, the pressure booster communicative with the second chamber when the pressure fluid is supplied to the first chamber to boost pressure of the pressure fluid by using part of the pressure fluid from the second chamber. A second accumulator accumulates the pressure fluid whose pressure is boosted by the pressure booster.

A harvesting system includes a header pivotally attached to a combine. The header includes a center section to which a left wing and right wing are pivotally attached. A suspension system of the harvesting system includes first and second engageable states that enable dynamic wing behavior and reduce structural load. The first state corresponds to a harvesting configuration of the header in which the wings are allowed to pivot to allow the header to follow changes in terrain. The second state corresponds to a configuration in which the header is elevated relative to the ground. In the second state, the ability of the wings to pivot is minimized as compared to the first state, which allows the header to be maintained in a substantially flat configuration while minimizing the amount of dynamic load imparted by the header on the combine during non-harvesting transport of the header.

This clutch actuator includes a hydraulic pressure generating mechanism (51) configured to operate a clutch (26) to provide a connected state or a disconnected state, a motor (52) configured to generate a rotary driving force for driving the hydraulic pressure generating mechanism (51) to a driving shaft (52a), a transmission mechanism (54) configured to transmit the rotary driving force generated in the driving shaft (52a) of the motor (52) to a driven member (54b) parallel to the driving shaft (52a) in an axial direction and disposed coaxially with a cylinder main body (51a), and a conversion mechanism (55) configured to convert the rotary driving force transmitted to the driven member (54b) into a reciprocal driving force of a piston (51b) in a stroke direction, wherein the hydraulic pressure generating mechanism (51), the motor (52), the transmission mechanism (54) and the conversion mechanism (55) are integrated as a unit.

A control system for construction machinery includes a main control valve installed in a hydraulic line between a hydraulic pump and actuators, and including a first group of electro proportional pressure reducing valves outputting a secondary pressure in proportion to an external pressure command signal to a first spool for controlling a first group of actuators of the actuators, and a second group of electro proportional pressure reducing valves outputting a secondary pressure in proportion to an external pressure command signal to a second spool for controlling a second group of actuators of the actuators, a first pressure sensor configured to detect the secondary pressure outputted from the first group of electro proportional pressure reducing valves and a second pressure sensor configured to detect the secondary pressure outputted from the second group of electro proportional pressure reducing valves, and a controller configured to output pressure command signals to the electro proportional pressure reducing valves corresponding to a manipulation signal of the construction machinery, and configured to compare the secondary pressures detected by the first and second pressure sensors and the pressure command signals to determine to determine whether or not the electro proportional pressure reducing valves fail.

An abnormality detection device for a hydraulic circuit including an oil pump capable of increasing oil a suction port and discharging the oil through discharge ports; a switching unit that switches between fully and partially discharged states; a pressure regulation unit that regulates an oil pressure; and a hydraulic pressure detection unit that detects the oil pressure includes: a storage unit that stores a maximum discharge pressure in the partially discharged state; a switching control unit that switches to either one of the discharged states; a pressure regulation control unit that sets a target pressure higher than the maximum discharge pressure in the partially discharged state, and performs pressure regulation control to achieve the target pressure; and a determination unit that determines whether the switching unit has a fixation abnormality in one of the discharged states by comparing a hydraulic pressure with the maximum discharge pressure in the partially discharged state.

A control device for suppressing engine load fluctuation according to main pump circuit conditions, wherein an assist torque calculation task includes a target engine torque calculation task separating smooth torque components from main pump load torque and setting a minimum value of either smooth torque component or engine setting torque as target engine torque, and a subtractor calculating target assist torque based on a difference between the main pump load torque and the target engine torque, the assist torque calculation task controlling a capacity of an assist pump based on the target assist torque and controlling switching between an assist mode and a charge mode.

A harvesting system includes a header pivotally attached to a combine. The header includes a center section to which a left wing and right wing are pivotally attached. A suspension system of the harvesting system includes first and second engageable states that enable dynamic wing behavior and reduce structural load. The first state corresponds to a harvesting configuration of the header in which the wings are allowed to pivot to allow the header to follow changes in terrain. The second state corresponds to a configuration in which the header is elevated relative to the ground. In the second state, the ability of the wings to pivot is minimized as compared to the first state, which allows the header to be maintained in a substantially flat configuration while minimizing the amount of dynamic load imparted by the header on the combine during non-harvesting transport of the header.

A system includes a control valve with a first control port and a second control port. An actuator of the system includes a piston between an extend chamber and a retract chamber. The system also includes a shutoff valve fluidically connected between the control valve and the actuator. The shutoff valve is passively controlled by a pressure differential between the extend chamber and the retract chamber. If the pressure differential between the extend chamber and the retract chamber exceeds normal operating pressures for the actuator, the shutoff valve closes to stop pressure and flow communication between the control valve and the actuator, thereby pausing the actuator. When the pressure differential between the extend chamber and the retract chamber returns to the normal operating pressures for the actuator, the shutoff valve passively returns to an equilibrium position that allows the actuator to resume operation.