A vehicle includes a chassis, a controllable vehicle component, a hydraulic circuit, a heater, a temperature sensor, and a controller. The hydraulic circuit includes a reservoir configured to store hydraulic fluid, a pump positioned to drive the hydraulic fluid from the reservoir and throughout the hydraulic circuit, and an actuator positioned to selectively receive the hydraulic fluid from the pump to selectively operate the controllable vehicle component. The heater is positioned to facilitate selectively heating the hydraulic fluid. The temperature sensor is positioned to acquire temperature data indicative of a temperature of the hydraulic fluid. The controller is configured to monitor the temperature of the hydraulic fluid and selectively activate at least one of the heater or the pump to thermally regulate the hydraulic fluid (i) to maintain the hydraulic fluid within a target temperature range and (ii) independent of (a) an operator input and (b) engagement of the actuator.

A fluid system includes a variable-speed and/or a variable-torque pump to pump a fluid, at least one proportional control valve assembly, an actuator that is operated by the fluid to control a load, and a controller that establishes a speed and/or torque of the pump and a position of the at least one proportional control valve assembly. The pump includes at least one fluid driver that provides fluid to the actuator, which can be, e.g., a fluid-actuated cylinder, a fluid-driven motor or another type of fluid-driven actuator that controls a load. Each fluid driver includes a prime mover and a fluid displacement assembly. The fluid displacement assembly can be driven by the prime mover such that fluid is transferred from the inlet port to the outlet port of the pump.

A hydraulic unit is provided with: a manifold which forms a hydraulic circuit; a tank which is joined to the manifold; and a hydraulic pump which suctions hydraulic fluid in the tank and supplies the hydraulic fluid to the manifold, wherein the base end portion of a suction strainer is fitted into the hydraulic pump, and the suction strainer has such a shape that the base end portion of the suction strainer is not separated from the hydraulic pump in a state where the leading end portion of the suction strainer is in contact with the tank and an opening through which the hydraulic fluid is introduced from the tank is provided at the leading end portion.

A hydraulic lifting mechanism suspension has a main valve in the activation position whereof at least one hydraulic accumulator is connected to a connection line of the lifting mechanism suspension acting in the lifting direction or to working line of the lifting mechanism suspension acting in the lifting direction. The lifting mechanism suspension is deactivated via a deactivation position of the main valve, while at the same time a connection for recharging or filling the hydraulic accumulator is opened.

A hydraulic pressure amplifier arrangement (1) is described comprising a supply port (A1), a pressure outlet (A2) connected to the supply port via check valve means (3), a tank port (B1), an intensifier section (5) having a high pressure piston (6) in a high pressure cylinder (7) which is connected to the pressure outlet (A2), a low pressure piston (8) in a low pressure cylinder (9) and connected to the high pressure piston (6), an intermediate space (11) between the high pressure piston (6) and the low pressure piston (8), a control valve (12) controlling a pressure in the low pressure cylinder (9), and a feeder arrangement of the intensifier section (5) including an input connection (19) connected to the supply port (A1) and a return connection (20) connected to the tank port (B1). Such a pressure amplifier arrangement should have a simple construction. To this end the feeder arrangement (19, 20) comprises throttling means (21).

A valve operating device includes a mounting for attachment to a vehicle and an elongate arm, the free end of which is only moveable across the underlying ground. The joints of the arm pivot around vertical axes and the arm is locked into a desired orientation by a brake at each joint. A valve turning machine is at the free end of the arm. The brakes are engaged and released by a control on the valve turning machine.

An unmanned underwater vehicle (UUV) with a hydraulic system (100) for use in cold surroundings and method of controlling such hydraulic system. The hydraulic system (100) comprises a hydraulic circuit (10). One or more tools (21,22) may be hydraulically operable via the hydraulic circuit (10). A pump (32) is configured to pressurize a flow of hydraulic fluid (F) via the hydraulic circuit (10) e.g. for actuating the tools (21,22). A valve system (40) comprises control valves (41,42,43) disposed in the hydraulic circuit (10) for controlling the flow of hydraulic fluid (F) through the hydraulic circuit (10). A controller (50) is configured to control one or more of the control valves (43) as a function of a temperature (T) of the hydraulic fluid (F).

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 fluid pump for a linear actuator causes a rod in the actuator to extend or retract by controlling fluid flow to and from portions of a fluid chamber on either side of a piston disposed within the fluid chamber and supporting the rod. The pump includes check valves that control fluid flow between a driven pump element and each portion of the fluid chamber and a shuttle movable in response to fluid pressure along a shuttle axis extending through the valves. At least one valve includes a valve member movable between a closed position and an open position defining a fluid flow path between the driven pump element and fluid chamber and means for limiting movement of the shuttle towards the valve such that the shuttle may, depending on the position of the limiting means, move the valve member to an intermediate position between the closed and open positions.

A turbine engine system includes an engine starter coupled to a turbine engine. A starter valve assembly is configured to provide a flow of fluid to the engine starter. The starter valve assembly has a flow control valve movable via an actuator. A pneumatic control is in communication with the actuator. A torque motor servo-valve is in communication with the actuator.