Abstract: A hydraulic system includes a hydraulic pump, a first hydraulic actuator, a second hydraulic actuator, a first control valve to control the first hydraulic actuator, a second control valve to control the second hydraulic actuator, the second control valve being arranged on a downstream side of the first control valve, and a discharge fluid tube in which the operation fluid flows. The hydraulic system further includes a first fluid tube in which a return fluid flows toward the second control valve. The hydraulic system further includes a second fluid tube in which a supply fluid flows toward the first hydraulic actuator, a third fluid tube coupling the first fluid tube to the discharge fluid tube, and a fourth fluid tube in which the return fluid flows toward the second fluid tube, the fourth fluid tube being connected to the first fluid tube.

Abstract: Disclosed herein are hydraulic actuators and methods for the operation of actuators having variable relative pressure ratios. Further disclosed are methods for designing and/or operating a hydraulic actuator such that the actuator exhibits a variable relative pressure ratio. In certain embodiments, the relative pressure ratio of the hydraulic actuator may be dependent on one or more characteristics (such as, for example, frequency or rate of change) of an oscillating input to the hydraulic actuator.

Abstract: A hydraulic drive system includes a swing directional control valve 81 and a third boom directional control valve 82 that are connected to a third hydraulic pump 33. Furthermore, the hydraulic drive system includes: a second auxiliary directional control valve 84 that is connected to the third hydraulic pump 33, and is connectable with a second special hydraulic actuator 64 for driving special attachments; and a first selector valve 96 that is connected to the third hydraulic pump 33 upstream of the second auxiliary directional control valve 84, and is connectable with an additional hydraulic pump 97. The first selector valve 96 switches the hydraulic fluid source of the second special hydraulic actuator 64 connected to the second auxiliary directional control valve 84 at least between the third hydraulic pump 33 and the additional hydraulic pump 97.

Abstract: A hydraulic pressure controller, cost of which can be cut, a straddle-type vehicle brake system, and a straddle-type vehicle are obtained. A hydraulic pressure controller (110) is used for the straddle-type vehicle brake system which includes a single system of a hydraulic circuit capable of controlling a hydraulic pressure and in which brake fluid in a wheel cylinder is released to a master cylinder without increasing the hydraulic pressure. A first coil (112B), a second coil (113B), and a hydraulic pressure detector (116) are erected on the same surface of a base body (111). An axis of the hydraulic pressure detector (116) is offset from a reference plane including an axis of the first coil (112B) and an axis of the second coil (113B), and is located between a first plane that is orthogonal to the reference plane and includes the axis of the first coil (112B) and a second plane that is orthogonal to the reference plane and includes the axis of the second coil (113B).

Abstract: A construction machine includes a hydraulic actuator and a processor. The processor is configured to detect a predetermined object present within a predetermined area around the construction machine, impose a motion restriction on the construction machine by decreasing the flow rate of hydraulic oil supplied to the hydraulic actuator, in response to detection of the object present within the predetermined area, and relax or cancel the motion restriction by increasing the flow rate to a level lower than before a start of the motion restriction or a level substantially same as before the start of the motion restriction, in response to a predetermined operation for relaxing or canceling the motion restriction being performed or in response to the object being no longer detected within the predetermined area, after the start of the motion restriction.

Abstract: A work vehicle includes an engine, a hydrostatic transmission, a storage device storing leakage flow rate data defining a relationship between a differential pressure of hydraulic fluid between the first drive circuit and the second drive circuit and a leakage flow rate of the hydraulic fluid in the hydraulic circuit in stalling, and a controller in communication with the storage device. The hydrostatic transmission includes a traveling pump, a hydraulic circuit with first and second drive circuits, and a traveling motor. The controller is configured to determine a target traction force of the work vehicle, determine a target differential pressure that is a target value of the differential pressure from the target traction force, determine the leakage flow rate from the target differential pressure with reference to the leakage flow rate data, and determine a target flow rate of the traveling pump from the leakage flow rate.

Abstract: A hydraulic system for a working machine includes a hydraulic pump to output operation fluid, a hydraulic actuator to be activated with the operation fluid, a first control valve to which the operation fluid outputted by the hydraulic pump is supplied, the first control valve being configured to control the hydraulic actuator, a second control valve to control the hydraulic actuator separately from the first control valve, a first fluid tube connecting the hydraulic pump and the first control valve, a second fluid tube branching from the first fluid tube and connecting to an input port of the second control valve, a third fluid tube connecting the first control valve and the hydraulic actuator, and a fourth fluid tube connecting to an output port of the second control valve and connecting to the third fluid tube.

Abstract: A control device, for a hydraulic consumer (22) and susceptible to vibrations, includes a valve (24) having a control spool (40) controllable by an actuating device (46). 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. The actuating device (46) has a motor (74). A load-pressure-dependent force on the control spool (40) can be generated by a control device (66). That 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.

Abstract: A hydraulic elevator may comprise a bidirectional pump that controls up and down motion of an elevator car. A VVVF drive may cause the bidirectional pump to provide working fluid in a controlled manner to a hydraulic jack that supports the elevator car. A control valve may be disposed between the bidirectional pump and the hydraulic jack so that the control valve can be closed when the elevator car needs to be held in place. To avoid pressure waves that propagate when the control valve is opened with disparate pressures on the pump and jack sides of the control valve, the bidirectional pump may adjust the pressure on the pump side of the closed control valve to the pressure on the jack side of the control valve before the control valve is opened.

Abstract: An object of the present invention is to provide a construction machine that allows easy and accurate calibration of a pressure sensor and enables accurate control of hydraulic actuators.

Abstract: To provide a construction machine that can highly precisely control branch flows from a hydraulic pump to a plurality of hydraulic actuators without being affected by load conditions. A controller (100) has a meter-out valve control section (140) configured to calculate a target opening area of a second meter-out valve (65a) (65b) according to a pressure difference between a supply pressure and a second meter-in pressure, or calculate a target opening area of a first meter-out valve (55a) (55b) according to a pressure difference between the supply pressure and the first meter-in pressure.

Abstract: Aspects of the disclosure relate to methods, apparatus, and systems for actuating a soft robot. An actuation system includes a camshaft, a motor configured to drive the camshaft to rotate around a rotational axis, and an air bladder configured to expel fluid from the air bladder during compression and draw fluid into the air bladder during decompression. The system further includes a cam coupled to the camshaft that is configured to rotate around the rotational axis when the camshaft is driven and compress or decompress the air bladder based on a physical profile of the cam as the cam rotates around the rotational axis. The system also includes a soft robot coupled to the air bladder, wherein the soft robot is actuated to move based on the fluid inserted into the soft robot during compression or the fluid removed from the soft robot during decompression.

Abstract: A control system includes a variable displacement hydraulic pump, the pump having an inlet for receiving fluid, an outlet for discharging fluid under pressure, and a pump displacement input, a hydraulic motor having an inlet and an outlet, a fluid circuit including a supply conduit for conducting fluid discharged by the pump to the motor and a return conduit for returning fluid discharged by the motor to the pump, a pump displacement control cooperating with the pump displacement input in order to vary a displacement of the pump, a control circuit in communication with the pump displacement control for controlling the pump output such that the motor is driven at a constant rotational speed, and a system controller in communication with the control circuit and a remote location to transmit and receive information to and from the remote location.

Abstract: Provided is a rotation drive device that has a wide rotary driving range, e.g. a rotary driving range of 0°-180°. Disclosed is a rotation drive device comprising a crank member rotatable about a crank axis, a first cylinder having a first piston and rotatable about a first cylinder rotation axis, and a second cylinder having a second piston and rotatable about a second cylinder rotation axis. The crank member and the first piston are coupled for rotation about a first piston rotation axis spaced from the crank axis. The crank member and the first piston are coupled for rotation about a second piston rotation axis spaced from the crank axis.

Abstract: A master cylinder device includes a reservoir tank, a master cylinder, a piston, and a pair of cup seals. The master cylinder includes a cylinder body having a cylinder chamber and a master port. The piston is inserted into the cylinder chamber, and has a relief port that communicates with the master port. The cup seals are provided on an inner circumference of the cylinder chamber, being positioned in front and rear of the master port, and seals a space between the inner circumference of the cylinder chamber and an outer circumference of the piston. The relief port is closed by the front cup seal, as the piston moves forward, to generate brake fluid pressure in a brake fluid in a hydraulic chamber. The relief port is tilted from a front side to a rear side, from the outer circumference toward an inner circumference of the piston.

Abstract: A piston pump includes a first biasing mechanism configured to bias a swash plate in accordance with supplied control pressure, a second biasing mechanism configured to bias the swash plate against the first biasing mechanism, and a regulator configured to control the control pressure led to the first biasing mechanism in accordance with discharge pressure of the piston pump, wherein the second biasing mechanism has a pressure chamber to which the discharge pressure is led, and a control piston configured to be biased toward the swash plate by the discharge pressure led to the pressure chamber, and the regulator has a biasing member configured to bias the control piston toward the swash plate, and a control spool configured to be moved in accordance with biasing force of the biasing member, the control spool being configured to adjust fluid pressure.

Abstract: A hydraulic cylinder comprising a cylinder, a piston element movably guided in the cylinder in a working direction and comprising an active surface, and a first opening for feeding a fluid into a cylinder chamber by the active surface. A working pressure of the fluid acting on the active surface drives the piston element in the working direction. The active surface includes a first partial surface and at least one second partial surface, the cylinder chamber being divided into a first sub chamber with the first opening by the first active surface and a second partial surface with a second opening by the second partial surface, and the partial surfaces are hydraulically separated from each other at least in a selectable operating mode.

Abstract: One object is to calculate the position of a rod of a linear actuator with a high precision. The linear actuator includes a rod capable of moving in an axial direction relative to a housing. The rod is moved by rotation of an output shaft of a motor. A position sensor for sensing the relative position of the rod relative to a preset reference position is provided in the housing. A rotation sensor for sensing the rotation angle of the output shaft of the motor is provided in the vicinity of the motor. The linear actuator includes a position calculating unit for calculating the position of the rod based on a position sensing value of the position sensor and a rotation angle sensing value of the rotation sensor.

Abstract: A calibration system is disclosed. The calibration system may include a sensor configured to measure a fluid level in a fluid tank of a machine, an actuator that, when actuated, affects a level of the machine, and a controller. The controller may be configured to: command actuation of the actuator at a current; receive, from the sensor and after commanding actuation of the actuator, information identifying the fluid level in the fluid tank; determine, based on the information identifying the fluid level in the fluid tank, whether there is a change to the fluid level in the fluid tank; and set an initiation current for the actuator at the current based on determining whether there is the change to the fluid level in the fluid tank.

Abstract: A work vehicle includes a bypass passage formed in an operational valve of a dump cylinder and configured to feed pressure oil from a hydraulic pump to a power steering device when the operational valve is under a neutral state and an oil feeding passage equipped with an orifice, the orifice-equipped oil feeding passage being configured to feed the pressure oil from the hydraulic pump to a rod side oil chamber of the dump cylinder when the operational valve is under the neutral state.