An oil returning valve set with multi-stage throttling control includes an oil returning channel implemented in oil in an oil hydraulic equipment. The two ends of the oil returning channel are connected to a pressurized oil collecting cavity and a pressurized oil discharging cavity respectively. A plurality of throttling valve plugs and oil returning valve plug are arranged in the oil returning channel, and a normally-open draining gap is also formed among the plurality of throttling valve plugs. When the oil returning valve plug is opened, a plurality of the throttling valve plugs are arranged in series to generate multi-stage throttling oil hydraulic draining control, which improves the problem that the valve opening allowance of the throttling valve for oil returning and pressure relief of traditional oil hydraulic equipment is not sufficient.

A line rupture safeguard for a hydraulic cylinder that has a connecting line between a connection for the hydraulic cylinder and a connection for a hydraulic unit, wherein a spring-biased closure unit in the connecting line is biased in a position releasing the connecting line, and at least partially closes the connecting line when a pressure differential in the connecting line is exceeded. A movable cam follower is provided that has a curved section which interacts with the spring-biased closure unit, and whose position dictates the spring bias of the closure unit and the pressure differential for at least partially closing the closure unit.

A valve unit includes a first piston, which has a first opening and a control chamber. A fluid connection between a first and a second port is closed or, in a position defined by the first piston, is held open in the event that a hose which is connected to the first port bursts. A pilot valve (48) is present, which has a core and a coil, and a fluid flow from the control chamber to the first port can be regulated by an electric current in the coil. The current is regulated by a logic unit which is suitable for receiving signals from at least one sensor, in particular a pressure sensor, an inertia detector and/or position sensor and for regulating the electric current in the coil.

An example valve includes: a main piston comprising: a channel that is fluidly coupled to a first port of the valve, a pilot seat, and one or more cross-holes fluidly coupled to a second port of the valve; a pilot check member configured to be subjected to a fluid force of fluid in the channel of the main piston acting on the pilot check member in a proximal direction; a solenoid actuator sleeve comprising a chamber; a first setting spring disposed in the chamber and configured to bias the solenoid actuator sleeve in a distal direction; and a second setting spring configured to bias the pilot check member in the distal direction, such that the first setting spring and the second setting spring cooperate to apply a biasing force in the distal direction on the pilot check member toward the pilot seat against the fluid force.

An improved method and circuitry for fluid power applications that provides energy savings through the recycling of normally exhausted pressure by direct transfer and accumulation of exhaust pressure for additional use, including from one end of the actuator to the opposite end or within the actuator itself and for use by other devices in separate systems.

A hydraulic control assembly includes means for holding pressure in a cylinder to inhibit boom or arm drop of a machine in the event that a hose between the cylinder and a main control valve (MCV) ruptures. The pressure holding means of the hydraulic control assembly include a hydraulic valve and a parts-in-body check assembly both configured for insertion into a valve cavity defined by a valve body. The hydraulic valve comprises a proportional piloted valve that controls pressure.

A line rupture safeguard for a hydraulic cylinder that has a connecting line between a connection for the hydraulic cylinder and a connection for a hydraulic unit, wherein a spring-biased closure unit in the connecting line is biased in a position releasing the connecting line, and at least partially closes the connecting line when a pressure differential in the connecting line is exceeded. A movable cam follower is provided that has a curved section which interacts with the spring-biased closure unit, and whose position dictates the spring bias of the closure unit and the pressure differential for at least partially closing the closure unit.

A hydraulic drive system includes an oil supply device, an oil return device and a hydraulic cylinder circuit component. The circuit component includes a hydraulic cylinder, a first and a second two-position two-way electromagnetic directional valves. The cylinder includes a first chamber and a second chamber that has a piston rod. A first port of the first valve connects with the first chamber and a first port of the second valve connects with the second chamber. When the oil supply device connects to a second port of the first valve and a second port of the second valve connects to the oil return device, the piston rod is extended outwards. When the oil supply device connects to the second port of the second valve and the second port of the first valve connects to the oil return device, the piston rod is retracted.

An example valve includes: a valve body defining a bore, an inlet port, an outlet port, and a signal cavity; a spool movable in the bore to shift between a first position and an intermediate position, where the spool has a first end and a second end, where the outlet port is fluidly connected to the second end, where the valve body defines a spring cavity adjacent the first end of the spool to house a spring, where the first end is subjected to a load-sense pressure signal, and where when the spool is in the first position, the spool disconnects the inlet port from the outlet port and connects the inlet port to the signal cavity; and a valve actuator that, when activated, connects the signal cavity to the second end of the spool to move the spool in the bore from the first position to the intermediate position.

A hydraulic drive system includes an oil supply device, an oil return device and a hydraulic cylinder circuit component. The circuit component includes a hydraulic cylinder, a first and a second two-position two-way electromagnetic directional valves. The cylinder includes a first chamber and a second chamber that has a piston rod. A first port of the first valve connects with the first chamber and a first port of the second valve connects with the second chamber. When the oil supply device connects to a second port of the first valve and a second port of the second valve connects to the oil return device, the piston rod is extended outwards. When the oil supply device connects to the second port of the second valve and the second port of the first valve connects to the oil return device, the piston rod is retracted.