A hydraulic actuator includes a switching part that is provided with an oil passage for sending pressurized oil generated by a hydraulic pump to a tool and returning return oil from the tool to the hydraulic pump. The switching part switches a route of at least one of the pressurized oil and the return oil. The switching part includes an operating portion (for example, an operation knob) and an axis portion (for example, a spool) that advances or retreats when the operating portion is turned. When the operating portion is turned, the axis portion advances or retreats in a direction orthogonal to a direction of turning the operating portion, whereby the route of the oil passage is switched.

A loader having a seat assembly mounted in the loader cab for movement along 2 axes. The cab pivots relative to the loader to permit access to loader components. The main operator controls in the loader are pilot valves operated by the loader operator without any electronic interfacing between the operator and the pilot valves. The pilot valves are supported directly by the seat assembly to move with the seat assembly and reduce inadvertent pilot valve motion induced by vehicle movement. Also provided is a hydraulic hose channeling arrangement which permits the support of hydraulic pilot valves relative to a seat assembly which is moveably mounted in a pilotable loader cab.

A pilot valve assembly (10) includes a cylindrical connector (12) having a first end portion (16) with external threading (18) for engaging a threaded control socket (106) of a hydraulic valve (100), and a second end (20) with an array of teeth (22) arrayed around its edge. A circumferential slot (24) around connector (12) is spaced from second end (20). The assembly also includes a pilot valve (26) with a mechanism for controlling a pressure within the hydraulic control valve actuator chamber. Pilot valve (26) is formed with a recess (28) having a complementary teeth (30) for engaging teeth (22) of connector (12) in a range of angular orientations. A clamping arrangement engages slot (24) and clamps pilot valve (26) to second end (20) of connector (12), thereby fixing an angular orientation of the pilot valve.

An example valve includes: a piston movable between a neutral position and an actuated position; a check poppet configured to be coupled to the piston, wherein in the neutral position, the check poppet is seated on a seat formed on an interior peripheral surface of the housing and blocks fluid at the first port; a solenoid actuator sleeve movable between an unactuated state and an actuated state, wherein in the actuated state, the solenoid actuator sleeve allows pilot fluid to apply a fluid force on the piston in a distal direction; and a feedback spring that applies a biasing force in a proximal direction on the piston against the fluid force, wherein the piston and the check poppet are configured to move axially to the actuated position based on a relationship between the fluid force and the biasing force.

A hydraulic cylinder spool valve device, which extends and retracts a cylinder rod of a hydraulic cylinder, includes: a first spool valve having a first dead band and a first opening characteristic; a second spool valve having a second dead band and a second opening characteristic; and a controller performing communication with the hydraulic cylinder by using the first spool valve and positioning the second spool of the second spool valve within the second dead band and performing communication with the hydraulic cylinder by using the second spool valve and positioning the first spool of the first spool valve within the first dead band, and adjusting a characteristic of a switching dead band between the first opening characteristic and the second opening characteristic.

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 hydraulic system includes a hydraulic pump to output an operation fluid, a hydraulic apparatus to be activated by the operation fluid, an operating member to operate the hydraulic apparatus, an operation valve to determine a pressure of the operation fluid in accordance with operation of the operating member, the operation fluid being supplied to the hydraulic apparatus, a first fluid tube connecting the hydraulic pump to the operation valve, a first working valve disposed on the first fluid tube, the first working valve being configured to change an opening aperture of the first working valve, a first outputting fluid tube connected to a section of the first fluid tube between the operation valve and the first working valve, and a second working valve disposed on the first outputting fluid tube, the second working valve being configured to change an opening aperture of the second working valve.

A hydraulic system in of a work machine includes a hydraulic pump to supply pilot hydraulic oil in a hydraulic oil reservoir. A travel pump is to drive a travel motor according to a pilot pressure of the pilot hydraulic oil. A target pilot pressure of the pilot hydraulic oil is input through a travel operation device to control, according to the target pilot pressure, the pilot pressure supplied from the hydraulic pump to the travel pump. A pilot oil path connects the travel operation device and the travel pump to supply the pilot pressure to the travel pump. 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 system for controllably moving a work implement of a work vehicle having a hydraulic fluid pump for providing fluid to the work implement, the system comprising: at least one operator command tool to produce an operator command signal to move the implement of the work vehicle; at least one sensor to sense a cylinder speed signal indicative of a speed of a hydraulic cylinder coupled to the implement; at least one valve to modulate the fluid flow of the hydraulic cylinder; and a controller.

An example valve includes: a piston movable between a neutral position and an actuated position, wherein in the neutral position: a second port of the valve is fluidly coupled to a first port, and a third port is fluidly decoupled from the second port; a solenoid actuator sleeve movable between an unactuated state and an actuated state, wherein in the actuated state, the solenoid actuator sleeve allows pilot fluid to apply a fluid force on a piston in a distal direction; a first feedback spring; and a second feedback spring disposed in series with the first feedback spring, wherein the first feedback spring and the second feedback spring cooperate to apply a biasing force in a proximal direction on the piston against the fluid force, wherein the piston is configured to move to the actuated position based on a relationship between the fluid force and the biasing force.