An example valve section includes: a housing having: (i) a longitudinal bore, (ii) a first and second workport passages configured to be fluidly coupled to an actuator, (iii) a first and second return passages, (iv) an open-center passage configured to be fluidly coupled to a source of fluid, and (v) a supply passage disposed between the first and second workport passages. The valve section also includes a spool movable in the longitudinal bore to shift between: (i) a neutral position that allows the open-center passage to permit fluid flow therethrough, and (ii) a shifted position that allows fluid to be diverted from the open-center passage to the supply passage, and connects the supply passage to either the first or second workport passage while connecting the other workport passage to a corresponding return passage of the first and second return passages.

A trip block is provided. The trip block includes a single housing which commonly houses multiple valve assemblies. Each valve assembly includes a rotary valve member arrangement. The rotary valve member arrangement includes a spool and a sleeve with a predefined radial clearance between the spool and sleeve.

In a valve device, first and second spool holes in which first and second spools of first and second unload valves are accommodated, respectively, are formed in a second valve block, opening portions of the first and second spool holes are formed in surfaces in outer surfaces of the second valve block other than contact surfaces with adjacent first and third valve blocks and in parallel with axes of spools accommodated in the adjacent first and third valve blocks.

A multi-control valve unit includes a housing with built-in spools that are parallel to each other. The housing includes pilot chambers formed therein, the pilot chambers corresponding to both ends of the spools. Solenoid proportional valves are mounted to the housing, such that the solenoid proportional valves are connected to the respective pilot chambers. A hydraulic pressure generator is mounted to the housing, such that the hydraulic pressure generator is connected to the solenoid proportional valves. The hydraulic pressure generator includes an electric motor and a pump.

A manifold block is provided for locating between a hydraulic pressure supply and a piece of equipment, such as a material handler. The manifold block allows for bidirectional flow and provides both flow and pressure control in the supply direction, but not in the return direction. The manifold block allows for the equipment to be protected from experiencing fluid pressure or a flow rate that is higher than limits set in the manifold block, thereby protecting hydraulically powered equipment, e.g., a material handler, regardless of the hydraulic supply parameters of a machine to which it is attached.

A hydraulic valve body, comprising two main lines for bringing pressurized hydraulic fluid into the body's channel system and further out of the channel system. The body further comprises at least two outlet fittings for conducting hydraulic fluid from the body's channel system to actuators and two respective inlet fittings for conducting hydraulic fluid from the actuators back into the channel system.

A method for forming hydraulic oil passages for hydraulic actuators according to an aspect of the present invention includes: forming a valve block mount surface including first and second regions on an outer surface of a housing; collecting valves for hydraulic actuators belonging to a main function group to a main function valve block that is mountable directly or indirectly on the first region; collecting valves for hydraulic actuators belonging to an additional function group to an additional function valve block that is mountable directly or indirectly on the second region; and mounting the valve blocks on corresponding regions of the valve block mount surface, and thereby, the hydraulic actuators to be mounted are fluidly connected to each other so that the hydraulic actuators are operable by using hydraulic oil from a common oil source.

A hydraulic system according to an embodiment of the present invention comprises: a main hydraulic pump for discharging a hydraulic fluid; a plurality of driving apparatuses operating by receiving the hydraulic fluid; a parallel flow path through which the hydraulic fluid discharged by the main hydraulic pump flows; a plurality of control spools respectively connected to the parallel flow path in parallel to control the supply of hydraulic fluid to the plurality of driving apparatuses; and a plurality of electronic proportional decompression valves for adjusting a pilot pressure, applied to the respective control spools to be proportional to a current signal which has been input, wherein, if the plurality of control spools do not operate, the hydraulic fluid discharged by the main hydraulic pump is drained into an oil tank via the parallel flow path without passing through the plurality of control spools.

Arrangements of a flow path to achieve a series circuit, a regeneration circuit and a float/passive regeneration circuit. For example, a valve body having a spool bore, a valve inlet, a plurality of cavities opening into the spool bore and a spool disposed in the spool bore. A first cavity fluidly connected to a tank passage, a second cavity fluidly connected to a first work port, a third cavity fluidly connected to an inlet of another valve, a fourth cavity fluidly connected to a second work port, a fifth cavity fluidly connected to the valve inlet, a sixth cavity fluidly connected to the first work port, a seventh cavity, an eighth cavity fluidly connected to the valve inlet, a ninth cavity fluidly connected to the inlet of the other valve and a tenth cavity fluidly connected to the valve inlet.

The present disclosure relates to an adjustment system a method for compensating for temperature variations in a spool valve. The spool valve and adjustment system may be parts in a duplex hydraulic actuator. The adjustment device comprises a spring, a pivot point, and a shape memory alloy (SMA) device. The spring and SMA device are disposed on either side of the pivot point to hold the pivot point in a first position. The SMA device is configured to change size in response to a temperature change so as move the pivot point to a second location. This may eliminate force fight in the duplex hydraulic actuator by preventing asynchronous activation of the spool valves due to thermal expansion within the spool valves.