To make it possible to control supply, discharge, and recycled flow rates independently of each other for the stick cylinder in a construction machine comprising first and second stick spool valves respectively connected to first and second hydraulic pumps. [Solution] A poppet valve is provided at upstream side of the first stick spool valve for controlling a supply flow rate from first hydraulic pump, the first stick spool valve is configured to supply hydraulic flow from the poppet valve to the stick cylinder without restricting the flow, and when the stick cylinder is extended, the poppet valve is configured to control supply flow rate from the first hydraulic pump to head side oil chamber, the first stick spool valve is configured to control recycled flow rate from a rod side oil chamber to the head side oil chamber, and the second stick spool valve is configured to control the supply flow rate from second hydraulic pump to head side oil chamber and the discharge flow rate from the rod side oil chamber to an oil tank.

A milling machine may have a frame, a milling drum attached to the frame, and ground engaging tracks that support the frame and propel the milling machine in a forward or rearward direction. The milling machine may have a tank that stores hydraulic fluid. The milling machine may also have at least one actuator connecting the frame to the tracks. The actuator may adjust a height of the frame relative to a ground surface. A fluid conduit may connect the tank to the actuator. The milling machine may have a flow sensor in the fluid conduit. The flow sensor may determine a flow parameter associated with a flow of the hydraulic fluid into or out of the actuator. The milling machine may also have a controller that determines a height of the frame relative to the ground surface based on the flow parameter.

Provided is a pneumatic actuator control device including detectors that are disposed in an air supply passage leading from an air supply source to a solenoid valve or in an air exhaust passage leading from the solenoid valve, and that detect the flow volume or the pressure of the air in the air supply passage, or detect the flow volume or the pressure of the air in the air exhaust passage; and an operational state determination unit that, on the basis of data representing a change in the flow volume or the pressure of the air in the air supply passage, or in the flow volume or the pressure of the air in the air exhaust passage, as detected by the detectors, determines the operational state of a pneumatic actuator connected to the solenoid valve.

A controller calculates the ratio between the sum of estimated demanded powers of a plurality of first actuators and the sum of estimated demanded powers of a plurality of second actuators, and calculates, on the basis of the ratio, first and second command values for adjusting allocation between a first allowable torque of a first pump and a second allowable torque of a second pump, and first and second regulators adjust the first and second allowable torques, on the basis of first and second output pressures of first and second torque control valves, such that the first and second allowable torques become values to which a predetermined allowable torque is allocated according to the ratio described above, and control the delivery flow rates of the first and second pumps such that the respective consumed torques of the first and second pumps do not become larger than the first and second allowable torques. Thus, the present invention efficiently performs torque allocation between the first and second pumps (a plurality of hydraulic pumps) to thereby enable effective utilization of the torque generated by the prime mover without wasting the torque.

A method and system for removing material build-up in a mixing chamber of a rotary mixer machine. The system includes one or more actuators coupled to the mixing chamber and to a frame of the rotary mixer machine. Further, the system includes a controller configured to receive an input and activate the one or more actuators in response to the input to induce a forward and backward rocking motion in the mixing chamber to cause a dislodgement of the material build-up from the mixing chamber. The mixing chamber executes the forward and backward rocking motion between a first position and a second position about an axis disposed transversally to a length of the rotary mixer machine.

A solenoid driven actuator system includes a first solenoid having at least one pressure input and a pressure outlet downstream from the at least one pressure input. The system includes a second solenoid having at least one pressure input and a pressure outlet downstream from the at least one pressure input. The system includes a pressure-switching valve operatively coupled to the first and second solenoids. The system includes an actuator operatively coupled to the pressure outlet of the second solenoid.

A valve has a housing which has at least two fluid openings, through which fluid can flow, and a further opening, at least one valve seat which is assigned to one of the fluid openings, and at least one closure member which is adjustable to release and/or close the at least one valve seat, the at least one valve seat which adjoins a cavity through which fluid can flow being formed on a housing part. The valve includes a sensor device which closes the opening in a fluid-tight manner and can acquire data about the fluid is arranged in the further opening. A valve island is furthermore described.

A hydraulic pressure control unit according to the present invention is a hydraulic pressure control unit for a vehicular brake system and includes: a discharge channel (140), from which a brake fluid is discharged, a pressure of the brake fluid being increased by a pump (60); and a pulsation reducer (100) provided to an intermediate portion of the discharge channel (140). The pulsation reducer includes: a pressure change suppressor (110), a volume of which varies according to the pressure of the inflow brake fluid; and a throttle valve (120) arranged on a downstream side of the pressure change suppressor (110) in the discharge channel (140). The throttle valve (120) includes: a first housing (121) having an end surface (121a), one end of which is opened and the other end of which is provided with a first through-hole (121b), the brake fluid flowing into the first through-hole (121b); a first valve body (122) movable in an axial direction of the first housing (121) in the first housing (121); and a first spring member (124) urging the first valve body (122) in a direction toward the first through-hole (121b) of the first housing (121). The first valve body (122) includes a seal section (122b) that closes the first through-hole (121b) of the first housing (121) and is formed with a throttle hole (122ba).

A hydraulic active suspension flow control system includes a hydraulic oil tank, a variable displacement pump with an oil suction port communicating with the hydraulic oil tank, a check valve, a servo valve, a suspension cylinder controlled by the servo valve, an engine revolution speed sensor configured to detect an engine revolution speed, a vehicle speed sensor configured to detect a vehicle speed, an oil pressure sensor configured to detect an accumulator outlet pressure, a flow controller configured to control displacement of the variable displacement pump by receiving data from the engine revolution speed sensor, the vehicle speed sensor and the oil pressure sensor, and a relief valve connected to the check valve in parallel and provided at an oil outlet of the variable displacement pump. The variable displacement pump is connected to an engine through a clutch; and an accumulator is connected between the servo valve and the check valve.

A controller calculates the ratio between the sum of estimated demanded powers of a plurality of first actuators and the sum of estimated demanded powers of a plurality of second actuators, and calculates, on the basis of the ratio, first and second command values for adjusting allocation between a first allowable torque of a first pump and a second allowable torque of a second pump, and first and second regulators adjust the first and second allowable torques, on the basis of first and second output pressures of first and second torque control valves, such that the first and second allowable torques become values to which a predetermined allowable torque is allocated according to the ratio described above, and control the delivery flow rates of the first and second pumps such that the respective consumed torques of the first and second pumps do not become larger than the first and second allowable torques. Thus, the present invention efficiently performs torque allocation between the first and second pumps (a plurality of hydraulic pumps) to thereby enable effective utilization of the torque generated by the prime mover without wasting the torque.