Abstract: A hydraulic system for a working machine, includes a hydraulic device to change a flow rate of an operation fluid. The hydraulic device includes a first hydraulic receiver to which the operation fluid is applied, a second hydraulic receiver to which the operation fluid is applied, and a movable portion to be moved by the operation fluid applied to any one of the first hydraulic receiver and the second hydraulic portion. A hydraulic system further includes a differential pressure regulator to supply the operation fluid to the first hydraulic receiver and the second hydraulic receiver, the differential pressure regulator being configured to regulate a differential pressure between a first pressure that is a pressure of the operation fluid applied to the first hydraulic receiver and a second pressure that is a pressure of the operation fluid applied to the second hydraulic receiver.

Abstract: A liquid-pressure driving system includes: a pump connected to an actuator through two pressure liquid passages; pressurizing mechanisms interposed on the passages and applying pressure to the operating oil returning from the actuator; a low pressure selector valve connected to parts of the passages and introducing to a cooling passage the operating liquid having lower pressure between the operating liquids flowing through the two pressure liquid passages; a restrictor mechanism interposed on the cooling passage; a cooler apparatus interposed on the cooling passage downstream of the restrictor mechanism, the cooler apparatus cooling the operating liquid flowing through the cooling passage; and a pressure liquid returning mechanism connected to parts of the two pressure liquid passages, each of the parts being at one side of the corresponding pressurizing mechanism close to the pump, the pressure liquid returning mechanism returning the cooled operating liquid to the two pressure liquid passages.

Abstract: A drive module with a hydraulic circuit that includes a reversible motor, a reversible pump driven by the reversible motor, a hydraulic reservoir, a first conduit coupling a first inlet/outlet of the reversible pump to the hydraulic reservoir, a second conduit coupling a second inlet/outlet of the reversible pump to the hydraulic reservoir, first and second hydraulic cylinders, and first and second one-way valves. The first hydraulic cylinder has a third inlet/outlet that is coupled to the first conduit between the reversible pump and the hydraulic reservoir. The second hydraulic cylinder has a fourth inlet/outlet that is coupled to the second conduit between the reversible pump and the hydraulic reservoir. The first one-way valve is disposed in the first hydraulic conduit between the first hydraulic cylinder and the reservoir. The second one-way valve is disposed in the second hydraulic conduit between the second hydraulic cylinder and the reservoir.

Abstract: A hydraulic system for providing hydraulic power to the work implements and subassemblies on an earth-moving machine such as a loader includes a first hydraulic pump and a second hydraulic pump. The first hydraulic pump can be associated with a lift circuit including a lift arm that can be raised and lowered with respect to the machine. The second hydraulic pump can be associated with both a tilt circuit for tilting a bucket pivotally connected to the lift arm and a steering circuit for steering the machine. The lift circuit and the tilt and steering circuits can be operated concurrently and independently of each other due to the arrangement of the first hydraulic pump and the second hydraulic pump.

Abstract: In order to avoid cavitation in a boom cylinder head end at the beginning of a dig cycle, fluid from an alternate source is supplied to the head end before or in addition to fluid supplied by the main boom-up hydraulic circuit. In one embodiment, an electronic hydraulic valve, related sensors, and control system determines the beginning of a dig operation and uses fluid at an intermediate pressure to rapidly provide fluid to a boom head end cylinder to prevent voiding or cavitation before fluid under high pressure from the main pump can be brought to the cylinder. An on/off fluid switch is activated early in a dig operation to address low pressure at the boom cylinder head end and provide an alternate path for fluid into the cylinder in reaction to the boom being lifted by a motion of the stick and bucket in contact with the work surface.

Abstract: The present disclosure relates to a hydraulic pressure control device for a swing motor for construction machinery, and more particularly, to a hydraulic pressure control device for a swing motor for construction machinery, which supplements working fluid in the swing motor when a turning operation of an upper body of construction machinery is performed and then stopped. The hydraulic pressure control device for the swing motor for construction machinery according to the present disclosure including the aforementioned configuration may rapidly secure the amount of makeup fluid required by the swing motor when the swing motor is stopped by directly receiving the working fluid discharged from the hydraulic pump P, thereby improving durability of equipment and preventing a cavitation phenomenon.

Abstract: An electric motor includes one or more separate coil sets arranged to produce a magnetic field of the motor. The electric motor also includes a plurality of control devices coupled to respective sub-sets of coils for current control. A similar arrangement is proposed for a generator. A coil mounting system for an electric motor or generator includes one or more coil teeth for windably receiving a coil for the motor and a back portion for attachably receiving a plurality of the coil teeth. A traction control system and method for a vehicle having a plurality of wheels independently powered by a respective motor. A suspension control system and method for a vehicle having a plurality of wheels, each wheel being mounted on a suspension arm of the vehicle and being independently powered by a respective motor.

Abstract: A hydraulic system with an improved complex operation is provided, which can prevent the generation of shock in a boom by delaying pressure supply during start and end of pilot signal pressure supplied to a spool for controlling an option device when a boom ascending operation and an operation of an option device are simultaneously performed or when such a simultaneous operation of the boom and the option device switches over to an independent operation of the boom.

Abstract: An electric actuator of the present invention includes a hydraulic fluid supply device and an actuator actuated in response to an input of hydraulic fluid from a variable-volume pump. The hydraulic fluid supply device includes an adjustable-speed motor, the variable-volume pump which is driven by the adjustable-speed motor and ejects hydraulic fluid, an electric motor control unit which controls the adjustable-speed motor so as to achieve an intended rotation speed, and a pump control unit which controls the variable-volume pump so that the ejection volume of the variable-volume pump decreases with an increase in the ejection pressure of the variable-volume pump.

Abstract: An open hydraulic circuit comprising a main pump (P), a hydraulic motor (M), two main ducts (10, 12) constituting a feed main duct and a discharge main duct and connected to the pump or to a reservoir (R) via a feed selector (14). The circuit further comprises a multifunction valve device comprising a multifunction selector (20) for connecting the main duct that is at the higher pressure to a pressure limiter (24) and for connecting the main duct that is at the lower pressure to booster means (16), and for interconnecting the main ducts by connecting them to the pressure limiter when the pressures in the main ducts are substantially mutually equal.

Abstract: A hydrostatic transmission of a hydrostatic-mechanical power distribution transmission in which the high-pressure limiting valves in the hydrostatic transmission are eliminated or adjusted to enable a working pressure higher than the working pressure on which the maximum pressure is based. For short time intervals, a pressure substantially higher than the pressure on which the maximum pressure is based under constant load of the hydrostatic transmission, can be adjusted. The hydrostatic transmission has high-pressure sensors connected with the control of the hydrostatic-mechanical power distribution transmission.

Abstract: A control device for a construction machine according to the present invention is configured so that in the construction machine provided with an automatic stop function which automatically stops an engine by an engine controller upon a predetermined automatic stop condition being met, and a hydraulic lock function which sets a hydraulic actuator locked in an inactive state by a hydraulic lock controller, there is provided a restart switch, where after an automatic stop of the engine, when the restart switch is operated, a restart command is transmitted to the engine controller via a route independently of that of an engine switch and independently of a hydraulic unlock condition, and the engine is restarted.

Abstract: The invention relates to a hydraulic drive, especially for two-cylinder thick matter pumps. Said hydraulic drive comprises at least one main pump (10) embodied as a hydraulic variable displacement pump, and two hydraulically actuatable drive cylinders (20, 22) that are each connected to a connection line (16, 18) of the main pump (10) by means of pump connections mounted on one end thereof, forming a closed hydraulic circuit, and communicate with each other at the ends thereof opposing the pump connections (24, 26) by means of a swinging oil line (28). The hydraulic drive also comprises a feed pump (42), by which means pressurized oil is fed from an oil tank to the current low-pressure side into the hydraulic circuit, and a flushing branch (52), by which means a flushing oil flow is branched off from the current low-pressure side under a limited pressure into the oil tank (44).

Abstract: A priority flow rate control valve (30) distributes pressurized working oil discharged from a hydraulic pump (10) driven by an electric motor (11) to a power steering device (20) first, and distributes the residual pressurized working oil to a cargo handling device (19). The rotation speed of the electric motor (11) and the distribution ratio of the pressurized working oil of the priority flow rate control valve (30) vary depending on the operation states of these devices (19, 20). By decreasing the rotation speed of the electric motor (11) at a rate smaller than a normal decrease rate when the cargo handling device (2) stops operation in a state where the power steering device (20) and the cargo handling device (19) are in operation, a kickback in a steering wheel (7) due to a response delay of the priority flow rate control valve (30) can be prevented.

Abstract: A forward/backward switching control apparatus for a hydraulic drive vehicle that includes the following structures. A variable displacement type hydraulic pump driven by an engine for discharging pressure oil in both directions. An electromagnetic pump inclination angle control mechanism making the discharge displacement of the variable displacement type hydraulic pump variable and for causing the same to discharge in both directions. An electric control outputting signals to run the hydraulic drive vehicle forward, backward and forward/backward. A control device outputting, when the electric control is switched forward/backward to output the forward/backward signal and when the time for switching the forward/backward signal is not longer than a preset time, a first modulate signal for delaying the return times from the forward position to the neutral position and from the backward position to the neutral position to the electromagnetic pump inclination angle control mechanism.

Abstract: A valve device (10) for at least one hydraulic motor suitable for driving a mass of large inertia. The device includes first and second ducts (12, 14) serving to be connected to respective ones of the two main ducts (feed or discharge) of the motor, and an auxiliary duct (15) connected, for example, to a booster duct. The device can have two configurations, depending on which of the main ducts has the higher pressure, in which configurations the main duct at high pressure is isolated, while the main duct at low pressure is connected to the auxiliary duct. The device includes time delay means (36, 46, 38, 48) suitable for limiting the speed of transition between one and the other of the first and second configurations when the difference between the pressures in the first and second main ducts (12, 14) changes sign.

Abstract: A method and an apparatus for driving a hydraulic system of a construction machine, in particular a hydraulic excavator, having a plurality of control blocks which are fed via at least one pump each and each drive a plurality of hydraulically operated actuators of the construction machine. At least two control blocks are designed to drive the same actuator. The delivery capacity of the pump of the second control block can be connected up to the actuator via a delay element.

Abstract: A hydraulic pump assembly (10) for powering a hydraulic torque wrench (24) is air-powered and has hydro-pneumatic control circuitry (39) which continues operation of an air motor (18) which drives the hydraulic pump (16) for a post-advance period after an advance actuator (55) is deactuated. Operation of the pump (16) is continued for a period sufficient to retract a double-acting torque wrench (24), to permit subsequent advances of the wrench (24) within the post-advance period without restarting the pump (16) or to permit a single acting wrench to be moved from one fastener to the next within the post-advance period without restarting the pump (16). Operation of the pump (16) is terminated when the post-advance period expires if the advance actuator (55) is not reactuated, so as to conserve energy and avoid unnecessary heating of the hydraulic fluid.

Abstract: A fluid control system (50) is provided for a work machine (10) having first and second compacting drums (14,16). First and second hydraulic motors (28,32) are connected in series and power first and second vibratory mechanisms (26,30) located within the first and second compacting drums (14,16). A control valve (60) supplies pressurized fluid to the first hydraulic motor (28). The pressurized fluid is transferred through a bypass circuit (74) around the second hydraulic motor (32). A sequencing device (80) closes the bypass circuit (74) transferring the pressurized fluid to the second hydraulic motor (32) after actuation of the first hydraulic motor (28).

Abstract: A hydraulic pump assembly for powering a hydraulic torque wrench is air-powered and has hydro-pneumatic control circuitry which continues operation of an air motor which drives the hydraulic pump for a post-advance period after an advance actuator is deactuated. Operation of the pump is continued for a period sufficient to retract a double-acting torque wrench, to permit subsequent advances of the wrench within the post-advance period without restarting the pump or to permit a single acting wrench to be moved from one fastener to the next within the post-advance period without restarting the pump. Operation of the pump is terminated when the post-advance period expires if the advance actuator is not reactuated, so as to conserve energy and avoid unnecessary heating of the hydraulic fluid.

Abstract: A hydraulic deceleration control for a hydraulic motor includes a pilot operated control valve for controlling fluid flow through a pair of motor lines connected to the opposite sides of the hydraulic motor. A valve device is disposed to communicate a source of pressurized fluid to a fluid energy storage device when the control valve is in its open position and to release the pressurized fluid contained in the storage device when the control valve is moved from the open position to its closed position. A throttle orifice releases the fluid from the storage device at a controlled flow rate. A pilot operated diverter valve is disposed in series with an orifice disposed between the motor lines to control fluid flow through the orifice and has a spring disposed at a first end resiliently biasing the diverter valve to its closed position.

Abstract: This disclosure is the use of high efficiency turbomachinery designs to achieve high efficiency thermodynamic cycles. The high efficiency thermodynamic cycles are referred to as the Modified Ericsson cycles, an expansion of the regenerative Brayton cycle. A Modified Ericsson cycle can include 2,3,4, or more stages (number of intercooling and heat/reheat cycles between stages) that achieve higher efficiencies and power density (net output power/cycle weight flow rate) than those of regenerative and nonregenerative Brayton cycles. Also included is a high temperature tip-turbine driven compressor design for Brayton, Modified Ericsson and other power/refrigeration cycles.

Abstract: A vehicle convertible top is moved by hydraulic cylinders between extreme raised and lowered positions. The cylinder ends are connected to ports in a reversible hydraulic pump in one end of an elongated housing, which has a reservoir in the other end, separated by a pump cap. The pump cap houses two fluid circuits connecting the pump to the ends of the cylinders. Each circuit has an end of cycle hydraulic locking device comprising a normally-closed valve and a valve actuator. The circuit valves are alternately opened by pump pressure to pressurize one end of the cylinders to alternately raise and lower the top. The opened valve closes when the pump ceases operation, preventing fluid backflow through the one circuit to the pump. This hydraulically locks the top in extreme raised and lowered positions to facilitate top latching and tonneau installation.

Abstract: A gas cylinder control system for use with machine systems such as die stamping systems that includes at least one gaseous fluid cylinder associated with the machine system, gaseous intensifier control cylinder normally operated in timed relation to the gaseous cylinder and a passage providing communication between the gaseous cylinder and the gaseous intensifier control cylinder. The gaseous intensifier cylinder operates at substantially higher pressure than the die cylinder. A normally closed control valve is provided in the passage and is operable to open the passage in time relation to the operation of the machine system in order to apply the higher gaseous pressure of the gaseous intensifier cylinder to the gaseous cylinder and lock the gaseous cylinder and prevent it from moving until the control valve is actuated to close the passage thereby providing a predetermined time delay.

Abstract: An electro-hydraulic valve-actuator system (30) includes an electric motor (58) for driving a hydraulic pump (60), with an electrical control circuit (68) energizing the electric motor to thereby furnish hydraulic fluid to a valve actuator (16). A timer (90, 92) times activation of the electric motor and extinguishes such activation at expiration of a time period required to approximately move a valve (22) to a desired position. A four-way electric solenoid valve (66) is coupled to the electrical control circuit for channeling pumped hydraulic fluid to either close or open the valve. An adjustable hydraulic bypass relief valve (76) is coupled to the hydraulic pump for establishing a hydraulic-fluid pressure provided by the pump. Individual electro-hydraulic valve-actuator systems of this invention can replace a pneumatic valve-actuator system, or electro-mechanical valve actuators.

Abstract: To inhibit potentially damaging cold startup of a hydrostatic unit in a vehicle transmission, a portion of the makeup fluid pump to the hydraulic pump and motor loop circuit of the hydrostatic unit is directed through a branch line including a viscosity insensitive, flow regulating fluidic element and a viscosity sensitive fluidic element. The latter element develops a fluidic signal varying as a function of fluid viscosity, which is utilized to control a valve to prevent over-pressurization of the loop circuit and to control a transmission controller to condition the transmission to neutral until the hydraulic fluid warms to a safe operating viscosity.

Abstract: A device for controlling the pressure in an auxiliary-pressure supply system of a hydraulic brake unit for automotive vehicles, which device comprises a diaphragm-type or bladder-type accumulator equipped with a hydraulic and electric switching arrangement by way of which the hydraulic pressure in the pressure accumulator can be reduced to a predetermined value after the engine of the vehicle has been turned off. An electromagnetic multidirectional control valve is used to divert hydraulic fluid back to a reservoir through a pressure-limiting valve connected downstream thereof. After the engine of the vehicle has been turned off, the multidirectional control valve remains open until the accumulator pressure has decreased to at least the gas inflation pressure of the accumulator. The invention reduces permeation of gas molecules through the diaphragm of the accumulator into the hydraulic fluid and thus effects a longer useful life of the pressure accumulator.

Abstract: An electroresponsive device is energized to actuate an internal combustion engine throttle for switching the engine from idle to a higher speed. The engine drives a hydraulic pump that supplies fluid through a control valve, then a cylinder lock, for driving hydraulic work cylinders. A first switch responds to a low pressure level being exceeded, due to fluid being directed by the control valve to an actuator, to increase engine speed, thereby making the pump pressure higher. A second switch responds to the higher pressure to continue the increased engine speed. When the control valve is restored to neutral position, the hydraulic fluid bypasses through the control valve directly to a sump and the second switch responds to the lower pressure by allowing the engine to go idle speed. A time delay device is provided for disabling the first switch during the time that pressure is dropping from the higher level to below the lower level.

Abstract: The hydraulic power system includes a single electrical motor for driving a fluid pump which supplies fluid under pressure to a plurality of series connected fluid motors, with the first motor in the series directly to the pump outlet and the last motor in the series to a fluid reservoir that constitutes the fluid source for the pump. The electrical motor is operable in response to a call for the actuation of any one of said fluid motors, and requires a maximum power output relative to the pump fluid capacity so that the fluid pressure and flow characteristics delivered by the pump satisfy the full load operating requirements of the last fluid motor in the series of motors when all of the other fluid motors are under full load operation.

Abstract: A drive system for construction machinery in which hydraulic circuit is provided with a plurality of variable-displacement hydraulic pumps and a plurality of hydraulic actuators, each pump being connected in closed circuit to one or a plurality of the actuators via a solenoid-operated valve or valves to drive a movable member or members connected to the actuator or respective actuators when pressurized fluid is supplied to the actuator or actuators from the pump. At least one of the selected hydraulic actuators is further connected in closed circuit through a solenoid-operated valve to at least one of the hydraulic pumps other than the hydraulic pump which is connected in closed circuit to the hydraulic actuator. The hydraulic circuit means is controlled such that timing for switching the solenoid-operated valves is controlled in conjunction with the operation of the pump so as to absorb the shock which would otherwise be produced when each actuator is rendered operative and inoperative.

Abstract: An apparatus for closing the guide vanes of a water turbine, for example, by means of a servo-motor controlled by a distributing valve responsive to the variation in the speed of the water turbine. The closing speed of the servo-motor is controlled to vary stepwisely by controlling the flow of the operating oil discharged from the servo-motor by a throttle control valve. The throttle transfer valve is controlled by first and second fluid actuators which are controlled by a first transfer valve operated by the closing operation of the servo-motor, a second transfer valve, and a time delay means.