A speed controller capable of controlling an action speed of an external cylinder in one stroke in a step-wise manner. The speed controller includes a first flow path and a second flow path that allow a first port and a second port to be in communication with each other. The first flow path is provided with a first check valve for allowing flow from the first port to the second port. The second flow path is provided with a first needle valve, and an opening hole of the first check valve is constituted as a part of a flow path. The first needle valve adjusts the flow rate by changing an opening area of the opening hole with a tip portion fixed on a piston in the cylinder chamber. The speed controller further includes a third flow path allowing the first port and the cylinder chamber to be in communication with each other. The third flow path is provided with a second check valve for allowing flow from the first port to the cylinder chamber.

A steering device includes: a cylinder demarcated into first and second chambers by a piston; a main valve having first and second shuttle chambers; a hydraulic source having first and second discharge ports; a first oil passage configured to connect the first chamber and the first shuttle chamber; a second oil passage configured to connect the second chamber and the second shuttle chamber; a third oil passage configured to connect the first shuttle chamber and the first discharge port; a fourth oil passage configured to connect the second shuttle chamber and the second discharge port; and a tank connected to the main valve via the third oil passage and the fourth oil passage. One of the first shuttle chamber and the second shuttle chamber of the main valve is in an opened state when the hydraulic source is stopped.

A main flow path that introduces high-pressure air to an air cylinder, or discharges exhaust air therefrom, includes a sub flow path provided alongside the main flow path; an exhaust flow rate adjustment unit that suppresses the operation speed of the air cylinder by adjusting the flow rate of the exhaust air flowing through the sub flow path; and a switching valve that is connected between the air cylinder, the main flow path and the sub flow path, and that connects the main flow path and the sub flow path to the air cylinder in a switching manner. The switching valve is constituted by a spool valve.

A hydraulic system includes a first electric machine connected to a first hydraulic machine and a second electric machine connected to a second hydraulic machine. An output side of the second hydraulic machine is connected to an input side of the first hydraulic machine. A hydraulic consumer is hydraulically coupled to an output side of the first hydraulic machine via a supply line and is powered by the first hydraulic machine. A return line hydraulically couples the hydraulic consumer to an input side of the first hydraulic machine. The second hydraulic machine provides a flow of hydraulic fluid to the input side of the first hydraulic machine if a requested flow from the first hydraulic machine exceeds a flow of the return line and recuperates energy if the requested flow from the first hydraulic machine is lower than the flow of the return line.

Method for controlling a hydraulic system for a working machine, the system including a first electric machine connected to a first hydraulic machine the first hydraulic machine including an input side and an output side a second electric machine connected to a second hydraulic machine the second hydraulic machine including a high-pressure side and a low-pressure side the high-pressure side connected to the input side; a hydraulic consumer coupled to the output side via a supply line and configured to be powered by the first hydraulic machine; a first return line hydraulically coupling the hydraulic consumer to the input side and to the high-pressure side; wherein the method includes detecting a return flow from the hydraulic consumer through the first return line; and controlling the second hydraulic machine to maintain a pressure in the first return line at a pressure level higher than a predetermined minimum pressure level.

A power drive for a passenger and/or cargo elevator—or any conveyance-using stored high pressure compressed air as a primary source, producing high pressure hydraulic fluid energy to move a servo-controlled hydraulic motor, mechanically connected to the hoisting mechanism of the elevator, is disclosed. The electric power driving the air compressor is not affected by the load of the elevator (e.g. number of passengers). The electric current is consumed to charge a high pressure air tank. The compressor is operated only when the elevator is in in a parked position, thus electric power consumption level is by no means correlated to the operational mode of the elevator motion.

A valve structure (1) for driving reversible ploughs (40), comprising a first port (3) adapted to be in fluid communication with a pump (P) in a first configuration of the plough (40) and adapted to be in fluid communication with a tank (T) in a second reversed configuration of the plough (40), and a second port (4) adapted to be in fluid communication with the tank (T) in the first configuration of the plough (40) and adapted to be in fluid communication with the pump (P) in the second reversed configuration of the plough (40), a body (2) which includes a first seat (5) and a second seat (6), the seats housing respective moving spools (13, 14), a first interconnection port (7a) for the connection of the valve structure (1) to a first chamber (10a) of a first hydraulic cylinder (10) for longitudinally aligning the plough (40), and a second interconnection port (7b) for the connection to a second chamber (10b) of the first hydraulic cylinder (10), a third interconnection port (8a) for the connection of the valve structure (1) to a first chamber (12a) of a second hydraulic cylinder (12) for reversing the plough (40), and a fourth interconnection port (8b) for the connection to a second chamber (12b) of the second hydraulic cylinder (12). The valve structure (1) comprises hydraulic components configured to control the relative displacement of the spools (13, 14) to automatically control the movement of the cylinders (10, 12). A check valve (31) enables the fluid to flow in the second reversed configuration of the plough (40).

A flow controller that changes the flow rate of air exhausted from an air cylinder in mid-stroke includes a first switching valve displaced from a first position to a second position under the effect of pilot air, and causing one port of the air cylinder to communicate with a first channel at the first position, exhausting air exhausted from the one port of the air cylinder while reducing the flow rate of the air using a first regulating valve at the second position. Since the pilot air is taken into the first switching valve from a second channel in a system different from the system of the first channel, a second regulating valve can be adjusted without being affected by the degree of opening of the first regulating valve.

A hydraulic pressure control unit according to the present invention is a hydraulic pressure control unit for a vehicular brake system and includes: a discharge channel (140), from which a brake fluid is discharged, a pressure of the brake fluid being increased by a pump (60); and a pulsation reducer (100) provided to an intermediate portion of the discharge channel (140). The pulsation reducer includes: a pressure change suppressor (110), a volume of which varies according to the pressure of the inflow brake fluid; and a throttle valve (120) arranged on a downstream side of the pressure change suppressor (110) in the discharge channel (140). The throttle valve (120) includes: a first housing (121) having an end surface (121a), one end of which is opened and the other end of which is provided with a first through-hole (121b), the brake fluid flowing into the first through-hole (121b); a first valve body (122) movable in an axial direction of the first housing (121) in the first housing (121); and a first spring member (124) urging the first valve body (122) in a direction toward the first through-hole (121b) of the first housing (121). The first valve body (122) includes a seal section (122b) that closes the first through-hole (121b) of the first housing (121) and is formed with a throttle hole (122ba).

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.