Abstract: A hydrostatic transmission system includes a fluid-driven motor and an integrated pump assembly connected to the fluid-driven motor to provide fluid to operate the fluid-driven motor. The integrated pump assembly includes a pump with at least one fluid driver comprising a prime mover and a fluid displacement assembly to be driven by the prime mover such that fluid is transferred from a first port of the pump to a second port of the pump. The pump assembly also includes two valve assembles to isolate the pump from the system. The hydrostatic transmission system also includes a controller that establishes at least one of a speed and a torque of the at least one prime mover to exclusively adjust at least one of a flow and a pressure in the hydrostatic transmission system to an operational set point.

Abstract: A rod assembly for a fluid pressure cylinder includes a rod member and a packing that is mounted on an outer circumferential part of the rod member and slides along a slide hole. Assembly is simple because a conventional hard piston is not used. The assembly can be carried out simply by hand without the use of a dedicated tool. Thus, the rod assembly simplifies assembly work.

Abstract: An example valve assembly is configured: generate a valve load-sense pressure signal indicative of a pressure level at a workport of an actuator; generate a pilot fluid signal to be communicated to a worksection of a valve assembly to enable shifting a spool in the worksection; compare a first pressure level of the valve load-sense pressure signal to a second pressure level of the pilot fluid signal; and communicate the pilot fluid signal to a load-sense port fluidly coupled to a load-sensing source of pressurized fluid when the second pressure level of the pilot fluid signal exceeds the first pressure level of the valve load-sense pressure signal.

Abstract: A device having a hybrid hydraulic-electric architecture includes a hydraulic pump/motor having first and second ports, and an electric motor. The device is configured to connect to two or more pressure rails, each pressure rail containing hydraulic fluid at a different pressure than the other pressure rails. A flow of hydraulic fluid from one of the pressure rails is driven through the hydraulic pump/motor, and a pressure difference exists between the first and second ports. The electric motor is configured to control a flow rate of the flow of hydraulic fluid and/or the pressure difference.

Abstract: A linear actuator system includes a linear actuator and at least one integrated pump assembly connected to the linear actuator to provide fluid to operate the linear actuator. The integrated pump assembly includes a pump with at least one fluid driver comprising a prime mover and a fluid displacement assembly to be driven by the prime mover such that fluid is transferred from a first port of the pump to a second port of the pump. The pump assembly also includes two valve assembles to isolate the pump from the system. The linear actuator system also includes a controller that establishes at least one of a speed and a torque of the at least one prime mover to exclusively adjust at least one of a flow and a pressure in the linear actuator system to an operational set point.

Abstract: A single-rod hydrostatic actuator or pump-controlled actuator, comprises a hydrostatic pump connected in a closed circuit to a single-rod hydraulic cylinder where the cylinder velocity is directly controlled by the pump flow, without the need of intermediary valves. Due to the absence of throttling losses, the efficiency of hydrostatic actuators is considerably superior to the efficiency of conventional valve-controlled circuits. However, because of the differential areas at the cap and rod sides of the cylinder, the flows coming into and out of the cylinder do not match. Several attempts have been made to this date to produce a stable, robust and reliable circuit that can be used in everyday applications but no circuit has ever been conceived to reach the high standards of reliability and robustness required by industry. The current invention solves the problem of the differential flows with a design that is reliable, oscillation-free and robust.

Abstract: A hydrostatic transmission system includes a hydraulic motor and at least one proportional control valve and at least one pump connected to the hydraulic motor to provide fluid to operate the hydraulic motor. The at least one pump includes at least one fluid driver having a prime mover and a fluid displacement assembly to be driven by the prime mover such that fluid is transferred from the pump inlet to the pump outlet. The hydrostatic transmission system also includes a controller that establishes at least one of a speed and a torque of the at least one prime mover and concurrently establishes an opening of the at least one proportional control valve to adjust at least one of a flow and a pressure in the hydrostatic transmission system to an operational set point.

Abstract: 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.

Abstract: An electro-hydrostatic actuating drive has a variable-volume and/or variable-speed hydraulic machine, which is driven by an electric motor, for the provision of a volumetric flow of a hydraulic fluid. Furthermore, the actuating drive comprises a cylinder with a piston, a piston rod and a first piston chamber, a valve with a first position and a second position, which valve can be moved by a first hydraulic actuator into the first position and by a second hydraulic actuator into the second position, wherein the second position controls a greater volumetric flow of the hydraulic fluid than the first position, a sink, a main line which connects a first piston chamber of the cylinder to the sink and in which the hydraulic machine is arranged, an auxiliary line which connects the first piston chamber to the sink and in which the valve is arranged, a first control line to the first hydraulic actuator, and a second control line to the second hydraulic actuator.

Abstract: A work machine includes an electric drive system. The work machine includes a prime mover, a machine controller, and a hydraulic control system. The hydraulic control system includes a pump, a control valve and a retarding control valve. The pump is configured to supply pressurized fluid to the hydraulic control system via a supply line. The control valve is fluidly coupled to the pump via the supply line, and includes a pressure relief valve. The retarding control valve is fluidly connected to the pump and the control valve. The retarding control valve includes a solenoid valve, an orifice and a check valve. The solenoid valve is coupled to the machine controller, the orifice restricts a flow of the pressurized fluid through the supply line, and the check valve is coupled to a discharge line, which branches from a point along the supply line between the solenoid valve and the orifice.

Abstract: Provided is an accumulator for easier maintenance of a metal bellows. The accumulator includes a housing having a shell provided with an opening portion and a disk-shaped base body to which one end of a metal bellows with an outside diameter smaller than the inside diameter of the opening portion is welded and fixed, the interior of the housing partitioned on the inside and outside of the metal bellows in a tightly closed manner, in which the base body is formed to have an outside diameter greater than the outside diameter of the metal bellows, and the base body is fixed detachably to the shell.

Abstract: An actuator includes: a casing; a pressure reducing valve and a piston. The pressure reducing valve is provided in the casing to reduce a pressure of a driving fluid supplied from an outside of the casing to a predetermined level. The piston is provided in the casing to form a pressure chamber together with the casing. The piston is driven by the driving fluid that has been pressure-reduced to the predetermined level.

Abstract: To provide a work machine that can stop unexpected operation of actuators faster than it actually occurs even if unintended operation occurs at the time of gate lock lever switching that leads to such unexpected operation. In the work machine, a controller switches a lock valve from a lock position to a release position in a case where a lock operation device is operated from a permission position to a prohibition position; decides, on the basis of a result of detection by a pressure sensor, whether or not a pilot hydraulic fluid has been output from a pilot valve until first time elapses after the lock valve is switched to the release position; keeps the lock valve at the lock position if it is decided that the pilot hydraulic fluid has been output until the first time elapses; and switches the lock valve from the lock position to the release position if it is decided that the pilot hydraulic fluid has not been output until the first time elapses, and second time elapses.

Abstract: An anomaly diagnosis device diagnoses anomaly of an oil-hydraulic operating mechanism that controls opening and closing of a circuit breaker. The anomaly diagnosis device includes: a first counter, which is a counter that counts the number of times of a pressure-increasing operation started upon a decrease in a hydraulic pressure maintained in the oil-hydraulic operating mechanism to a first reference pressure, and stopped upon an increase in the hydraulic pressure to a second reference pressure; a timer that measures an operation interval that is a time period from when a pressure-increasing operation is stopped until a next pressure-increasing operation is started; and an anomaly determiner that corrects, based on the operation interval, the number of pressure-increasing operations obtained based on a result of counting by the counter, and determines presence or absence of an anomaly in the oil-hydraulic operating mechanism using the corrected data of the number of pressure-increasing operations.

Abstract: A system for compensating for drift or movement of a hydraulic actuator connected to a machine's boom or similar elongate member that is caused, at least in part, by damping of mass-induced vibration. The system comprises a processing unit and a plurality of sensors operable to collect data from a control valve connected to an actuator's load holding chamber and to calculate additional volume present therein due to vibration damping. Using the calculated additional volume, the processing unit determines a hydraulic fluid flow rate appropriate to substantially reduce or eliminate the additional volume. The processing unit combines this flow rate with the hydraulic fluid flow rate necessary to cause operation of the actuator in response to the machine's operator input, and provides signals to the control valve causing actuation of the valve to output hydraulic fluid to the actuator at a rate equal to the combined flow rates.

Abstract: The present invention relates to A device for supplying hydraulic power, the device comprising two hydraulic circuits jointly feeding multi-cylinder hydraulic power transmission means in which each cylinder is connected to a single one of the hydraulic circuits independently of the others. Each hydraulic circuit includes a hydraulic pressure and flow rate generator and a pressure control module controlling said hydraulic pressure and flow rate generator so as to regulate the pressure of said fluid flowing in said hydraulic circuit as a function of said pressure of said fluid flowing in each hydraulic circuit and possibly as a function of one or more parameters external to said device.

Abstract: Concrete product machine apron gap adjustment by actuating a gapper mechanism to set a desired gap between a reciprocally-movable apron plate and an interchangeably installable mold assembly installed in a concrete products machine. The gapper mechanism sets a desired gap between the machine apron plate and the mold assembly by injecting an index amount of hydraulic fluid into fluid communication with the rod side of a primary apron plate positioning cylinder, causing the machine's apron plate to retreat a desired gap distance away from an engaged position against the mold assembly.

Abstract: A controller determines a compensation factor from an operating amount of an accelerator operating member and a hydraulic pressure of at least one of a first circuit and a second circuit. The controller determines a target vehicle speed from the operating amount of the accelerator operating member. The controller determines at least one of a target displacement of a travel pump and a target displacement of a travel motor from the target vehicle speed and the compensation factor.

Abstract: A hydraulic system (600) and method for reducing boom dynamics of a boom (30), while providing counter-balance valve protection, includes a hydraulic cylinder (110), first and second counter-balance valves (300, 400), first and second control valves (700, 800), and a selection valve set (850). The selection valve set is adapted to self-configure to a first configuration and to a second configuration when a net load (90) is supported by a first chamber (116, 118) and a second chamber (118, 116) of the hydraulic cylinder, respectively. When the selection valve set is enabled in the first and second configurations, the second and first control valve may fluctuate hydraulic fluid flow to the second and first chamber, respectively, to produce a vibratory response (950) that counters environmental vibrations (960) of the boom. When the selection valve set is not enabled, the first and second counter-balance valves are adapted to provide the hydraulic cylinder with conventional counter-balance valve protection.

Abstract: Provided is a slewing-type hydraulic work machine including a boom raising working pressure detection unit that detects boom raising working pressure, and a capacity control device that controls a slewing motor capacity during a slewing and boom-raising operation and performs detecting an actual slewing distribution factor correspondence value corresponding to a ratio of energy distributed to a slewing motor to energy of discharged hydraulic oil, setting a boundary value of the actual slewing distribution factor correspondence value to limit the ratio more with increase in boom raising working pressure, and a capacity operation of making the slewing motor capacity higher than a limit capacity within a slewing priority allowable period until the actual slewing distribution factor correspondence value reaches the boundary value during the slewing and boom-raising operation and limiting the slewing motor capacity to the limit capacity or less after the slewing priority allowable period.