A hydraulic system including a first cylinder conduit configured to couple to a cylinder, an auxiliary conduit configured to couple to a case drain conduit, and a pressure regulator coupled to the first cylinder conduit and to the auxiliary conduit. The pressure regulator may block fluid flow to the auxiliary conduit if a first fluid pressure is less than or equal to a threshold pressure and enable fluid flow if the first fluid pressure is greater than the threshold pressure. The hydraulic system further includes a supplemental conduit with a check valve that directs fluid from the auxiliary conduit to a reservoir. The check valve blocks fluid flow if a second fluid pressure is less than or equal to a third fluid pressure, and enables fluid flow if the second fluid pressure greater than the third fluid pressure.

A hydraulic system for a working machine includes a first electric machine connected to a first hydraulic machine; a second electric machine connected to a second hydraulic machine, an output side of the second hydraulic machine being connected to an input side of the first hydraulic machine; at least one hydraulic consumer hydraulically coupled to an output side of the first hydraulic machine via a supply line and configured to be powered by the first hydraulic machine; and a valve arrangement arranged between the hydraulic consumer and the first and second hydraulic machines, wherein the valve arrangement is configured to control a return flow of hydraulic fluid from the hydraulic consumer to either the input side of the first hydraulic machine or an input side of the second hydraulic machine based on a requested output pressure from the first hydraulic machine.

The present disclosure provides a compressed air processing system of which the operation of supplying compressed air and the regeneration operation can be efficiently controlled by an electronic control unit. In particular, the present disclosure is characterized in that the pressure of a regeneration sequence valve installed in a regeneration line is increased over a set pressure by controlling a valve, which is electronically controlled, to switch, so the opening time of the regeneration line is delayed in comparison to the opening time of an unloader valve, whereby regeneration efficiency is improved.

A pilot relief valve is provided, including: a sleeve, a valve body, a piston, an adjusting member, a support base, a blocking member and an elastic member, all disposed inside the sleeve. The support base includes a head portion and a rod portion, the head portion includes an exhaust channel penetrating the first surface, the rod portion includes an air intake channel communicating with the exhaust channel. The blocking member is disposed on the head portion. As such, the air in the sleeve is discharged through the inside of the support base, and the hydraulic oil fills the sleeve to maintain pressure balance so that the support base and the blocking member will not thrust, the perforation of the valve body and the outlet of the tipping valve remains unblocked, and the pressure of the hydraulic oil is stable when the hydraulic oil enters the hydraulic cylinder.

A valve body defines a work passage, a high-pressure channel fluidly connected to the work passage, a tank passage, and a cavity disposed between the high-pressure channel and the tank passage. The cavity fluidly connects the high-pressure channel and the tank passage. The cavity is defined at least in part by a first portion within which a relief valve threadedly engages, a second portion disposed adjacent to the high-pressure channel, and an annulus interposed between the first portion and the second portion. The annulus fluidly connects to the tank passage. A surface area of the relief valve exposed to the annulus is greater than a cross-sectional area of the high-pressure channel.

A valve device includes a relief valve configured to be opened when a pressure in a fluid pressure circuit reaches a predetermined pressure and to relieve a working fluid, a tank passage connected to a tank, a main relief passage connecting the relief valve and the tank passage, and a sub relief passage branching from the main relief passage and connected to the tank passage separately from the main relief passage.

An auxiliary hydraulic system including an accumulator, a control valve, and a hydraulic connector. The accumulator connects to a primary hydraulic system including a hydraulic pump, a brake circuit, and a steering circuit. The control valve selectively allows or prevents flow from an accumulator to at least one of the brake circuit and the steering circuit. The hydraulic connector selectively connects an external source to the accumulator and the control valve.

A hydraulic system for a machine includes an implement pump, a valve, and an implement valve subsystem. The implement pump includes a load sensing control, and the valve controls the flow of hydraulic fluid to the implement pump. The implement valve subsystem includes one or more implement control subsystems to control movement of an implement. The valve is an electrohydraulic proportional relief valve and includes a solenoid configured to adjust the pressure of hydraulic fluid delivered to the implement pump proportionally to a current delivered through the solenoid.

A downhole device for applying and regulating pressure to a hydraulic device. The downhole device includes a relief check valve, a pressure transfer check valve, a hydraulic chamber, an output port, and a fluid separator. Pressure from the hydraulic chamber is applied to the hydraulic device to actuate the hydraulic device.

An example valve includes a piston configured to block fluid flow from a first port of the valve to a second port of the valve when the valve is in a closed position; a relief mode spring applying a first biasing force on the piston in a distal direction; a reverse flow spring applying a second biasing force on the piston in a proximal direction, wherein the reverse flow spring is weaker than the relief mode spring; and a pressure setting spring applying a third biasing force on a check element in the distal direction, causing the check element to be seated when the valve is in the closed position.