A hydraulic system for recovering potential energy of a load implement of a mobile construction vehicle. The hydraulic system includes first and second actuators and control valving. The first and second actuators are configured to be coupled to the load implement for controlling raising and lowering of the load element. The control valving is operable between a first position at which, during a lowering of the load implement, the control valving directs hydraulic fluid from one of the first and second actuators to an accumulator to charge the accumulator, and a second position at which the control valving directs hydraulic fluid from the accumulator to one or more of the first and second actuators to power the one or more of the first and second actuators to raise the load element.

A hydraulic control valve unit includes an input port hydraulically coupled to a pump, a working port hydraulically coupled to the working load, and a return port connected to a hydraulic tank. The unit includes a control slide movable into different working positions in an axial direction for controlling a hydraulic flow between the hydraulic ports and a slide housing surrounding the control slide. The control slide includes a control segment which is delimited in the axial direction by a control edge, and cooperates with an axial housing segment of the slide housing for controlling a flow cross section for hydraulic flow at the control segment. The control slide is rotationally driven about an axis of rotation in a rotational direction. The control edge of the control segment or the housing segment cooperating with the control segment is designed such that the flow cross section has a different size depending on a rotational position of the control slide.

Flow control over a hydraulic pump and flow dividing control of a plurality of directional control valves associated with actuators can stably be exercised even in a case in which differential pressures across the directional control valves are quite low, an abrupt change in a flow rate of the hydraulic fluid supplied to each actuator is prevented and excellent combined operability is realized even in an abrupt change in a demanded flow rate at a time of transition from a combined operation to a sole operation, and realizing excellent combined operability, and a meter-in loss in each directional control valve is reduced to realize high energy efficiency. Demanded flow rates of the directional control valves are calculated from input amounts of operation levers, openings of flow control valves are controlled using the demanded flow rates, a meter-in pressure loss of a predetermined directional control valve is calculated from the demanded flow rates and meter-in opening areas of the directional control valves, and a set pressure of an unloading valve is controlled using a value of the meter-in pressure loss.

A hydraulic control valve unit includes an input port hydraulically coupled to a pump, a working port hydraulically coupled to the working load, and a return port connected to a hydraulic tank. The unit includes a control slide movable into different working positions in an axial direction for controlling a hydraulic flow between the hydraulic ports and a slide housing surrounding the control slide. The control slide includes a control segment which is delimited in the axial direction by a control edge, and cooperates with an axial housing segment of the slide housing for controlling a flow cross section for hydraulic flow at the control segment. The control slide is rotationally driven about an axis of rotation in a rotational direction. The control edge of the control segment or the housing segment cooperating with the control segment is designed such that the flow cross section has a different size depending on a rotational position of the control slide.

One object is to reduce a weight of a fluid actuator. The fluid actuator includes: a cylinder having an inner space and a first mounting portion, the inner space being partitioned into a first fluid chamber and a second fluid chamber, the first mounting portion being disposed on an end portion of the cylinder on an axial direction A side; and a piston rod configured to reciprocate in accordance with pressures in the fluid chambers. A wall portion defining the first fluid chamber in the cylinder is made of an iron-based alloy. A wall portion defining the second fluid chamber in the cylinder is made of an aluminum alloy. The piston rod is made of an iron-based alloy.

An example valve includes: a sleeve having a plurality of sleeve openings; a first conduit configured to be in hydraulic communication with a first chamber, where a first pressure sensor is disposed in the first conduit and configured to measure a pressure level of fluid in the first chamber; a second conduit configured to be in hydraulic communication with a second chamber, where a second pressure sensor is disposed in the second conduit and configured to measure a pressure level of fluid in the second chamber; a spool rotatable within the sleeve, wherein the spool includes a plurality of spool openings respectively corresponding to the plurality of sleeve openings; a rotary actuator coupled to the spool and configured to rotate the spool within the sleeve in clockwise and counter-clockwise directions; and a controller configured to cause the spool to rotate to one of a plurality of rotary positions.

A hydraulic fluid control valve (HFCV) configured to recirculate an exiting hydraulic fluid from a first hydraulic actuation chamber to a second hydraulic actuation chamber is provided. The HFCV includes a selectively movable spool having an inner fluid chamber configured to receive and deliver the exiting hydraulic fluid to one or both of either a sump or one of the first or second hydraulic actuation chambers.

The invention relates to a control device for a hydraulic consumer (22), susceptible to vibrations, comprising a valve (24) having a control spool (40), which can be controlled by means of an actuating device (46), wherein the valve (24) has a pressure supply port (P), to which a pressure compensator valve can be connected, which can be supplied with pressure fluid from a pressure supply device, wherein the actuating device (46) has a motor (74) and wherein a load-pressure-dependent force on the control spool (40) can be generated by means of a control device (66). In accordance with the invention, this force at the control spool (40) acts on an electronic motor controller (208) of the DC motor (74), which detects a change of the force and acts as a damping of the vibrations of the consumer (22) against this change of force.

A telescopic apparatus for a human-powered vehicle comprises a first hydraulic chamber, a second hydraulic chamber, a valve member, a cam member, and an actuator. The second hydraulic chamber is configured to be in fluid communication with the first hydraulic chamber. The valve member is configured to control a fluid communication between the first hydraulic chamber and the second hydraulic chamber. The cam member is rotatable about a rotational axis to move the valve member in a movement direction. The actuator is configured to rotate the cam member. The actuator includes an output shaft rotatable about an actuation rotational axis. The actuation rotational axis is offset from the rotational axis as viewed in the movement direction.

A regeneration valve includes a housing defining a first port, a second port, a third port, and a chamber fluidly communicating with the first, second, and third ports. The chamber has a valve element movable between a first position, in which the second port fluidly communicates with the first port, and a second position, in which the second port fluidly communicates with the third port. A resilient member biases the valve element towards the first position. In operation, a flow restrictor element moves between the first port and the second port for restricting fluid flow from the second port to the first port. At a predetermined flow rate between the second port and the first port, if a supply pressure of fluid at the actuation chamber exceeds the bias of the resilient member, the valve element moves to the second position for fluidly communicating the second and third ports.