A hydraulic system in a work machine includes a hydraulic pump to supply pilot hydraulic oil. A work hydraulic actuator is to move a work device of the work machine. A control valve is to control the work hydraulic actuator based on a pilot pressure of the pilot hydraulic oil. A target pilot pressure of the pilot hydraulic oil is input through the work operation device to control, according to the target pilot pressure, the pilot pressure supplied from the hydraulic pump to the control valve. A pilot oil path connects the work operation device and the control valve to supply the pilot pressure to the control valve. A drain oil path is divided from the pilot oil path. A pressure adjustment valve is provided in the drain oil path to adjust the pilot pressure to be less than the target pilot pressure when a condition is satisfied.

A pneumatic trip valve that may include a valve structure, a switch plate air path and an internal check valve. In various aspects, the pneumatic trip valve may be connected to a valve positioner, an actuator, or a combination thereof to control the operation of a fluid process control valve. In operation, the Pneumatic trip valve acts to put the actuator in a preset fail-safe position when the actuator loses sufficient pressure or communication from a main air supply, stored pressurized air from an actuator air reservoir, and/or an external air reservoir.

An output member (7) is inserted in a housing (5) so as to be movable in a left-right direction. A lock chamber (20) is provided to the right of the output member (7), as a first actuation chamber. Compressed air is supplied to and discharged from the lock chamber (20) through a first supply and discharge passage (24) provided in the housing (5). A first holding valve (30) provided to an intermediate portion of the first supply and discharge passage (24) is configured to close and open the first supply and discharge passage (24).

An electrical power generation system includes a hydraulic pump configured to be switchable between operating in a first pump direction and in a second pump direction opposite the first pump direction and a hydraulic motor operably connected to the hydraulic pump to convert hydraulic flow into electrical power. The hydraulic motor has a motor inlet passage and a motor outlet passage. A hydraulic block is located in flow communication with the hydraulic pump and with the hydraulic motor. The hydraulic block is configured such that hydraulic fluid flow exiting the hydraulic block toward the hydraulic motor is directed through the motor inlet passage, regardless of whether the hydraulic pump is operating in the first pump or the second pump direction.

An electrical power generation system includes a hydraulic pump configured to be switchable between operating in a first pump direction and in a second pump direction opposite the first pump direction and a hydraulic motor operably connected to the hydraulic pump to convert hydraulic flow into electrical power. The hydraulic motor has a motor inlet passage and a motor outlet passage. A hydraulic block is located in flow communication with the hydraulic pump and with the hydraulic motor. The hydraulic block is configured such that hydraulic fluid flow exiting the hydraulic block toward the hydraulic motor is directed through the motor inlet passage, regardless of whether the hydraulic pump is operating in the first pump or the second pump direction.

A hydraulic arrangement for a vehicle transmission includes a hydraulic pump for providing a system pressure for a first hydraulic system circuit and a lubrication pressure for a second hydraulic lubrication circuit. The arrangement also includes a control valve connected between a pump outlet of the pump and the two hydraulic circuits and has two different switching positions. The control valve, depending on its switching position, acts as a hydraulic connection between the pump and the system circuit or between the pump and the lubrication circuit.

A hydraulic arrangement for a vehicle transmission includes a hydraulic pump for providing a system pressure for a first hydraulic system circuit and a lubrication pressure for a second hydraulic lubrication circuit. The arrangement also includes a control valve connected between a pump outlet of the pump and the two hydraulic circuits and has two different switching positions. The control valve, depending on its switching position, acts as a hydraulic connection between the pump and the system circuit or between the pump and the lubrication circuit.

The present invention provides an improved high-low hydraulic system for compacting machinery, such as balers, horizontal balers, compactors, transfer station compactors, and the like. The high-low hydraulic system comprises at least one double rotary pump, a plurality of directional control valves, a pilot-operated back pressure reducing valve, a flow control valve, a plurality of one-way valves, and a plurality of pressure switches. The high-low hydraulic system may be regenerative or non-regenerative and provides many advantages over conventional hydraulic systems. Such advantages include greater system efficiency due to a reduced back pressure during the time of the retraction stroke and clever flow sequencing, mitigation of hydraulic shocks at the beginning and end of compaction and retraction strokes, and reduced cycle time of the cylinder during operation due to the concurrent filling of the rod end side during decompression of the blind end side after the compaction stroke. Moreover, the present high-low hydraulic system allows for the cylinder to operate at three or more independent speeds.

A control valve includes a housing formed with first and second supply ports, first and second actuator ports, and a pilot port, and a spool accommodated slidably in the housing, and the spool is configured to allow the first supply port and the pilot port to communicate with each other both at the first communication position and the second communication position.

A control valve includes a housing formed with first and second supply ports, first and second actuator ports, and a pilot port, and a spool accommodated slidably in the housing, and the spool is configured to allow the first supply port and the pilot port to communicate with each other both at the first communication position and the second communication position.