Abstract: A method for controlling a hydraulic control system that includes a variable pressure relief valve and may include steps for calibrating the hydraulic control system. The hydraulic control system may be calibrated by: controlling, with the controller, the variable pressure relief valve to move to a fully open position, increasing, with the pump, a fluid pressure upstream of the variable pressure relief valve, controlling, with the controller, the variable pressure relief valve to move from the fully open position toward a fully closed position by adjusting a control signal supplied to the variable pressure relief valve, monitoring, with the controller, the pressure detected by the pressure sensor, and recording, with the controller, a parameter of the control signal supplied to the variable pressure relief valve when the pressure detected by the pressure sensor reaches a target pressure.

Abstract: An example valve includes: a first port, a second port, and a load-sense port; a valve piston configured to block fluid flow from the first port to the second port when the valve piston is in a neutral position; a reverse flow spring applying a first biasing force on the valve piston in a proximal direction; and a pressure compensation spring disposed in a spring chamber and applying a second biasing force on the valve piston in a distal direction, wherein when pressure level of fluid at the second port is higher than pressure level of fluid at the load-sense port, fluid flows from the second port to the spring chamber and the load-sense port, and wherein when pressure level of fluid at the load-sense port is higher than pressure level of fluid at the second port, fluid of the load-sense port is provided to the spring chamber.

Abstract: A method for controlling a hydrodynamic machine, including the steps of: providing a hydrodynamic machine which includes a bladed primary wheel and a bladed secondary wheel, which together form a working chamber, which can be filled with a working medium from a working medium supply contained in a working medium reservoir, to transfer drive power hydrodynamically from the bladed primary wheel to the bladed secondary wheel by forming a working medium circuit in the working chamber; applying a control pressure to the working medium supply in order to force the working medium from the working medium supply into the working chamber; detecting, at least indirectly, a pressure increase in the working medium reservoir, when the control pressure is applied to the working medium supply; and determining, as a function of the pressure increase that has been detected, a fill level of the working medium supply in the working medium reservoir.

Abstract: A milling machine may have a frame, ground engaging tracks that support the frame, and an actuator that adjusts a height of the frame relative to the track. The milling machine may have a control valve that selectively controls a flow of fluid into or out of the actuator based on the current supplied to the control valve. The milling machine may have a controller that determines the amount of current required to operate the actuator at a nominal actuator velocity and supplies that current to the control valve. The controller determines a measured actuator velocity based on a time required to extend or retract the actuator by a predetermined length, and adjusts the amount of current based on the measured and nominal actuator velocities. The controller also supplies the adjusted amount of current to the control valve to adjust the height of the frame relative to the track.

Abstract: A system and method for the controlled lowering and lifting of a load are disclosed. The system and method may include operating a work machine having a hydraulic system including a hydraulic actuator for supporting a load, a first control valve in fluid communication with the actuator, and a controller for operating the first control valve. In one embodiment, the controller includes a first algorithm for operating the first control valve in a load lowering operation. When an operational fault within the hydraulic system is detected, the controller can be configured to enter into a safe lowering mode. In the safe lowering mode, the first algorithm is disabled and a pulse width modulation (PWM) current is sent from the controller to the first control valve. A user interface is provided to allow an operator to control the PWM current duty ratio to allow the load supported by the actuator to be lowered.

Abstract: An agricultural machine includes a float cylinder interconnecting a header linkage system and a frame of the machine. A first rod side accumulator and a second rod side accumulator are both in fluid communication with a rod side fluid port of the float cylinder. A first accumulator control valve is positioned to control the first rod side accumulator, and is selectively controllable between an open position allowing fluid communication between the first rod side accumulator and the rod side fluid port of the float cylinder, and closed position blocking fluid communication between the first rod side accumulator and the rod side fluid port of the float cylinder. The system provides a slower first float response with the first accumulator control valve open, and a faster second float response with the first accumulator control valve closed.

Abstract: A hydraulic system for operating a rear gate of a baler implement includes a hydraulic cylinder having a housing that defines an interior, and a piston that is moveably disposed within the interior of the housing. The housing includes a first fluid port and a second fluid port, each disposed in fluid communication with a first fluid volume of the hydraulic cylinder. A flow rate control valve is moveable between a first position for directing fluid to or from the first fluid port at a first flow rate, and a second position for directing fluid to or from the second fluid port at a second flow rate. The second flow rate is different than the first flow rate.

Abstract: A fluid actuated linear drive includes a drive housing and a drive member which is movable between two stroke end positions. The drive member has a drive unit with a drive piston which divides off two drive chambers from one another, the drive chambers via two housing channels being connected to axial housing coupling openings which are arranged on a housing rear side. A multi-function module is built onto the housing rear side in a position of use and includes components of an external end position setting device for the drive member and is furthermore provided with module block channel systems which communicate with the housing channels and can be used for the feed and discharge of a drive fluid when the multifunction module is built onto the drive housing in the position of use.

Abstract: Hydraulic systems and methods comprising a source of hydraulic pressure; a hydraulic load; and an energy recovery circuit. The source of hydraulic pressure is fluidly connected to the hydraulic load through a first hydraulic channel with an orifice. The energy recovery circuit includes a recovery channel which is fluidly connected at its first end to the orifice on the side of it which is connected to the source of hydraulic pressure, and which is fluidly connected at its second end to a hydraulic motor.

Abstract: A construction machine according to an exemplary embodiment of the present invention includes: an engine; a boom cylinder which is divided into a head side and a rod side; a regeneration line through which hydraulic fluid discharged from the head side of the boom cylinder moves when the boom descends; a regeneration motor which is connected with the regeneration line and is operated, and assists the engine; a pilot pump which generates a pilot pressure; a pilot line through which pilot hydraulic fluid discharged from the pilot pump moves; a regeneration connection line which connects the pilot line and the regeneration line; an on/off valve installed in the regeneration connection line; and a control device which closes the on/off valve when a pressure of the pilot line drops below a predetermined pressure or the hydraulic fluid discharged from the boom cylinder is supplied to the regeneration motor.

Abstract: The invention relates to a compressed-air supply system for operating a pneumatic installation in a pneumatic system of a vehicle, comprising: a compressed-air feed; a compressed-air connection point to the pneumatic installation; a venting connection point to the environment; a pneumatic main line between the compressed-air feed and the compressed-air connection point, which pneumatic main line has an air dryer; a venting valve, which is arranged on the pneumatic main line and is designed as a pilot valve and has a pilot connection point; a compressor having at least one compressor stage; and, in addition to the pneumatic main line, a pilot valve and a pneumatic pilot channel that connects the pilot valve to the pilot connection point of the venting valve.

Abstract: A fluid container for releasable connection to a vehicle component, wherein the fluid container has at least one fastening lug with an opening which is aligned with a plug-through opening in the vehicle component and the connection is secured by a locking pin which can be extended into the plug-through opening and the opening and/or opening and can be locked in an end position by a rectilinear plug-in movement in a plug-in direction; in order to increase the load-bearing capacity of the connection and to simplify the installation, it is proposed that the fastening lug has a locking device which is arranged in alignment with the respective opening and the locking device includes at least two elastically resilient tabs which act in a latching manner on a thickened locking portion of the locking pin and thereby secure the locking pin in its axial direction.

Abstract: 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.

Abstract: A hydraulic power generating system includes a hydraulic motor, a bidirectional generator connected to the hydraulic motor, a hydraulic cylinder, first and second tubes, a piston structure having a piston and first and second links, and a power driving device connected to the first link. The piston divides the hydraulic cylinder into first and second chambers. The first and second links are connected to the piston and disposed through the first and second chambers, respectively. The first tube is communicated with the first chamber and the hydraulic motor. The second tube is communicated with the second chamber and the hydraulic motor. When the power driving device drives the piston toward the first chamber, hydraulic oil is pumped to the hydraulic motor for rotating the bidirectional generator. When the power driving device drives the piston toward the second chamber, the hydraulic oil is pumped to rotate the bidirectional generator reversely.

Abstract: The subject matter of this specification can be embodied in, among other things, a rotary actuator that includes a housing defining a first arcuate chamber portion and comprising a first cavity, a first open end, a first seal carrier assembly defining a second arcuate chamber portion and comprising a second cavity in fluid communication with the first cavity, a first piston seal, a second open end, and a third open end opposite the second open end, a first face seal in sealing contact with the housing proximal to the first open end and the second open end, a rotary output assembly, and an arcuate-shaped first piston disposed in said housing for reciprocal movement in the first arcuate chamber portion and in the second arcuate chamber portion.

Abstract: A closed-circuit, self-contained hydraulic axis includes an electric motor, a hydraulic cylinder configured to be connected to a load and a main pump driven by the electric motor to pump hydraulic fluid through the circuit. Pressure connections of the pump are connected to the respective chambers of the cylinder such that the cylinder rod is configured to extend and retract depending on a direction of flow of the hydraulic fluid through the main pump. The hydraulic axis includes a main accumulator connected to the pump via first control valve, an energy storage accumulator connected to the pump via a second control valve, and a charge pump. The hydraulic axis is switchable between a first operating mode that is free of energy storage in the energy storage accumulator, and a second operating mode in which energy is stored in the energy storage accumulator.

Abstract: An actuator including a housing, an actuator rod and a snubber assembly. The actuator has an axis, the housing has a first end and an aperture positioned at the first end of the housing, and the actuator rod extends through the aperture along the axis of the actuator. The snubber assembly is mounted at the first end of the housing, and includes one or more energy absorbing devices. The snubber assembly is positioned on the housing such that an axis of each of the one or more energy absorbing devices is offset relative to the axis of the actuator. The snubber assembly is configured such that the one or more energy absorbing devices provide bidirectional end-of-stroke damping.

Abstract: A torque converter has a torus. The torus has a size set based on a flatness ratio obtained by dividing a width of the torus in an axial direction by a width of the torus in a radial direction, a thinness ratio obtained by dividing the width of the torus in the axial direction by an outer diameter of the torus, and an inner diameter ratio obtained by dividing an inner diameter of the torus by the outer diameter of the torus.

Abstract: To provide a construction machine that has a hydraulic system mounted thereon in which a closed-circuit pump, and an open-circuit pump and a proportional valve are arranged as a pair, and that makes it possible to use an unused open-circuit pump or proportional valve to accelerate the speed of a single rod hydraulic cylinder when the single rod hydraulic cylinder and a hydraulic motor are driven simultaneously. A controller (51) controls a cap-side selector valve (46) and a rod-side selector valve (47) such that a particular open-circuit pump (15) not connected to a single rod hydraulic cylinder (3) is connected to the single rod hydraulic cylinder, and controls an opening area of a particular proportional valve (49) provided on a flow line that connects a delivery port of the particular open-circuit pump to a tank, when the single rod hydraulic cylinder and a hydraulic motor (7) are driven simultaneously.

Abstract: An electro-hydrostatic actuator system for a press drive, having an upper piston with a press surface, which acts from a first direction, wherein the press surface of the upper piston is actuated by means of a piston rod in a hydraulic cylinder of the upper piston and traverses a first distance in a press run, and a first electro-hydrostatic actuator for driving the upper piston, comprising a first pump and a first motor generators which is controlled by a first controller. The system furthermore comprises at least one auxiliary piston with a press surface, which acts from a second direction opposite the first direction, wherein the press surface of the auxiliary piston is actuated by means of a piston rod in a hydraulic cylinder of the auxiliary piston and traverses a second distance in the press run, and a second electro-hydrostatic actuator for driving the at least one auxiliary piston, comprising a second pump and a second motor generator which is controlled by a second controller.