Abstract: Provided is a hydraulic control system for a construction machine, including: a control valve (31) for controlling supply and discharge of hydraulic fluid to and from an arm cylinder (4); an operation lever (6) for controlling the position of a spool of the control valve (31); a meter-out flow passage (34) for passing therethrough hydraulic fluid discharged from the arm cylinder; a variable restrictor (23a) provided in the meter-out flow passage; pressure sensors (41, 42) for detecting a magnitude of a negative load applied by an external force to the arm cylinder in a same direction as an actuation direction of the arm cylinder; and a controller (45) for reducing an opening area of the variable restrictor (23a) according to an increase in the magnitude of the negative load calculated with a detection value from the pressure sensors (41, 42).

Abstract: A hydrokinetic torque coupling device for coupling together driving and driven shafts, comprises a casing, impeller and turbine wheels, a torsional vibration damper, a turbine hub non-rotatably connected to the turbine wheel, and first and second vibration absorbers. Each of the first and second vibration absorbers is one of a dynamic absorber and a pendulum oscillator. The turbine hub is non-rotatably coupled to a driven member of the torsional vibration damper. The first vibration absorber is mounted to the turbine hub and the second vibration absorber is mounted to one of the turbine hub and the casing. The first vibration absorber and the second vibration absorber are tuned to address different orders of vibrations. The dynamic absorber includes an inertial member and a connecting plate coupled to the inertial member. The pendulum oscillator includes a support member and flyweights configured to oscillate relative to the support member.

Abstract: Provided is a hydraulic drive system including: first and second pumps; a first main supply fluid line and an optional supply fluid line leading to the first pump; a second main supply fluid line leading to the second pump; a main manipulating device for the main actuator; an optional manipulating device for the optional actuator; a bleed-off flow rate regulating section to change the bleed-off flow rate for the second pump; and a bleed-off control section to operate the bleed-off flow rate regulating section to change the discharge flow rate of the second pump in accordance with a control operation applied to the main manipulating device and to make a bleed-off flow rate in a specific combined manipulation state with simultaneous performance of a specific main control operation and an optional control operation be smaller than that in a single main manipulation state.

Abstract: A method and apparatus for a reciprocating pump assembly, including a crosshead and a connecting rod. The crosshead includes a main body having a cylindrical bore formed therethrough and defining a bearing surface, and a window formed through the main body and into the cylindrical bore. The connecting rod includes a small end disposed within the cylindrical bore and a beam portion extending through the window and being connected to the small end. In an exemplary embodiment, a bearing including a tubular body and a cutout is disposed within the cylindrical bore. In another exemplary embodiment, a clamp engages both the main body of the crosshead and the respective opposing end portions of the small end, thus reducing axial displacement of the small end relative to the crosshead.

Abstract: A piston pin assembly is provided including a cylindrical pin body having a hollow interior. A mass is disposed in the hollow interior of the cylindrical pin body and a viscoelastic, plastic, or elastomeric material is disposed in the hollow interior between the mass and the cylindrical pin body. The mass and viscoelastic, plastic, and elastomeric material provides a damper for the piston and piston pin to delay the acceleration of piston lateral motion and stabilize the piston rotation and reduce the noise and friction.

Abstract: A drive train configuration is disclosed. The drive train incorporates an engine having hydraulic pumps contained substantially inside the engine housing and with an engine shaft driving the hydraulic pumps. A porting block or center section is mounted to the engine housing to provide hydraulic communication between the hydraulic pumps located inside the engine housing and hydraulic motors located outside the engine housing. The hydraulic motor output shafts drive gears connected to axles to propel a vehicle.

Abstract: Disclosed is a hydraulic drive system capable of improving the fuel efficiency of a work machine by reducing the pressure loss and drag loss of a hydraulic pump. There are provided an electric motor M; a third pump P3 driven by the electric motor; a third pump hydraulic line L3 to which the delivered hydraulic fluid from the third pump is supplied; a third directional control valve V4 provided in the third pump hydraulic line, switch-operated by an arm operation device 19, and controlling the flow rate of the hydraulic fluid supplied to the arm cylinder 8 from the third hydraulic pump; and a controller 18 drive-controlling the electric motor, wherein the controller drives the third pump by the electric motor when a swing/arm combined operation is detected by pilot pressure sensors S6, S7, S10, S11.

Abstract: A fluid pressure cylinder which has a head cover and a rod cover provided on both ends of a cylinder tube, wherein the head cover and the rod cover are formed by casting such as die-casting. A first connecting channel which recesses in a groove shape in the outward radial direction is formed in the outer-circumferential surface of a first concave section of the head cover. A ring-shaped first holder is pressed into the first concave section, causing the formation of a cross-sectionally rectangular first connecting channel, the opening region of which is sealed. In addition, the first connecting channel connects a cylinder chamber of the cylinder tube and a first cushion chamber of the head cover.

Abstract: The invention is directed to controlling a hydraulic actuation system having at least one degree of freedom, a prime mover, at least one actuation module and a controller, with each actuation module including: an over-center variable displacement pump having a power input connection configured to power the pump from the prime mover and a displacement varying input for varying the displacement of the pump; a displacement varying actuator configured to modulate the displacement varying input of the pump; an output actuator in direct communication with the pump, the output actuator configured to drive a corresponding degree of freedom; and at least one sensor establishing a feedback measurement that represents a force or motion of the output actuator. Based on a value of each feedback measurement, the force or motion of the output actuator is regulated by controlling the prime mover and the displacement actuator for the output actuator.

Abstract: A hydraulic circuit for an agricultural implement consisting of a hydraulic cylinder that exerts a force on a component of the implement. A pressure reduction valve located between a hydraulic power source and the hydraulic cylinder maintains pressure to no more than a preset maximum to protect the hydraulic cylinder by routing excess hydraulic fluid back through a hydraulic line into a reservoir. A pressure relief valve with a preset maximum pressure greater than that of the pressure reduction valve is located between the pressure reduction valve and the hydraulic cylinder, and is connected to the reservoir through a dedicated return line. If hydraulic fluid pressure in the circuit increases to greater than the maximum of the pressure reduction valve, hydraulic fluid is diverted back to the reservoir through the pressure relief valve and a dedicated return line.

Abstract: A hydraulic system is disclosed. The hydraulic system may include a fluid source and an actuator having a first passage and a second passage. The hydraulic system may further include a pump having a first port connected to the first passage, a second port connected to the second passage, and a third port connected to the fluid source. The first and second passages may be connected to each other via the first and second ports, and the first passage and the low-pressure fluid source may be connected to each other via the first and third ports. They hydraulic system may further include a charge circuit fluidly connected to the first and second passages, and at least one damping control valve configured to selectively allow fluid from the pump to pass into the charge circuit to dampen pressure oscillations between the actuator and the pump.

Abstract: A brake apparatus is provided which has applicability to a wide range of vehicles. The brake apparatus includes a master cylinder provided in such a manner that a piston is axially operable in a master cylinder housing, and a stroke simulator including a reaction force piston axially operable by brake fluid introduced into a stroke simulator housing. The master cylinder housing is fixed to the stroke simulator housing. The stroke simulator housing is positioned between the master cylinder housing and a fixation piece structured to fix the stroke simulator housing to the vehicle. The fixation piece is spaced from the master cylinder housing.

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 first and second blocking valves (350, 450). A net load (90) is supported by a first chamber (116, 118) of the hydraulic cylinder, and a second chamber (118, 116) of the hydraulic cylinder may receive fluctuating hydraulic fluid flow from the second control valve to produce a vibratory response (950) that counters environmental vibrations (960) on the boom. The method may include measuring first pressure ripples at the second chamber and reducing a magnitude of second pressure ripples at the first chamber. The pressure ripples may be transformed into a flow command by multiplying the pressure ripples by a gain and/or phase shifting. The gain and/or the phase shifting may be adjusted by feedback.

Abstract: A bi-directional pump connected to a motor by a pair of supply/discharge lines; a regulator changes the bi-directional pump tilting angle; and a controller controls the regulator based on a turning signal outputted from a turning operation valve. At the turning acceleration, at which the signal increases, the controller calculates a motor flow rate passing through the motor and an instruction flow rate determined based on the turning signal. If the instruction flow rate is greater than a reference flow rate obtained by adding a predetermined value to the motor flow rate, the controller controls the regulator so the bi-directional pump tilting angle is adjusted to a tilting angle realizing the reference flow rate. If the instruction flow rate is not greater than the reference flow rate, the controller controls the regulator so the bi-directional pump tilting angle is adjusted to a tilting angle realizing the instruction flow rate.

Abstract: Cylinder for an actuator (11), in which said cylinder (10) comprises at least a liner (13) of a tubular shape developing along a longitudinal axis (X), a head portion (14) and a bottom portion (15), each disposed at one of the ends of the liner (13), and longitudinal tie rods (21) connected, externally to the liner (13), both to the head portion (14) and to the bottom portion (15); the longitudinal tie rods (21) are distanced with respect to each other on the circumference of the liner (13), they are made of a composite material formed by reinforcement fibers located in a matrix of binder material and wound between the head portion (14) and the bottom portion (15) according to a predominant orientation substantially parallel to said longitudinal axis (X), and have a continuous annular shape defined by two longitudinal branches (21a) connected by two opposite connection portions (21b, 21c).

Abstract: Embodiments of the inventive concept include a manufactured pressure vessel including pressure cells having an impermeable layer containing porous material in which air can permeate, and a big mass layer disposed atop the pressure vessel to pressurize the air within the pressure vessel. The impermeable layer can include rubber from recycled vehicle tires. The big mass layer can have a total weight of between one (1) million and one (1) billion tonnes, or more. The big mass layer can include a remediated upper surface. The pressure vessel can include an interface section through which the air can enter and exit the pressure vessel. Pressure lines can be coupled to the interface section. A turbine center can be coupled to the pressure lines to generate electricity in response to pressurized air received through the pressure lines, or to pump air through the pressure lines into the pressure vessel to pressurize the pressure vessel.

Abstract: A method is used to control a hydrostatic drive including a drive machine, a hydraulic pump coupled to the drive machine, and a hydraulic motor coupled to the hydraulic pump via a hydraulic working circuit. In the method, at least one of multiple manipulated variables of the hydrostatic drive is ascertained and set, in the course of a precontrol, from a specified setpoint value for at least one of the controlled variables, including a pressure in the hydraulic working circuit, a speed of the hydraulic pump, and an output variable of the hydrostatic drive. In the method, the remaining controlled variables and/or manipulated variables are automatically updated.

Abstract: A hydraulic brake mechanism for use in hydraulic systems to provide braking of a hydraulic motor is disclosed. The brake mechanism provides proper braking under a range of operating conditions, including (1) the start of flow from the pump to the brake and motor and braking is not desired; (2) operating conditions in which constant flow is provided from the pump to the brake and motor and braking is not desired; (3) operating conditions in which abrupt decreases of flow from the pump to the brake and the motor occur, for example where flow is reduced due to being drawn by another work element or hydraulic load, but under which a reduced supply flow is still present and braking is not desired; and (4) operating conditions in which the hydraulic flow from the pump to the brake mechanism and the motor is shut off completely and braking is desired.

Abstract: In a fluid transmission device in which a core is fixed to inner ends of a plurality of blades so as to form, together with a bowl-shaped shell and the blades, an impeller, the core including a plurality of latching holes with which a projecting piece projectingly provided at the inner end of the blade is latched and including a balance weight chip welded to the core, the balance weight chip includes a projecting piece-avoiding hole through which a portion, projecting from the latching hole, of the projecting piece extends, the balance weight chip being welded to the core with a whole of the balance weight chip in intimate contact with the core.

Abstract: A fluid circuit includes a pressure fluid source, a switching valve, and a cylinder device having first and second chambers and partitioned by a piston. A first accumulator is configured to communicate with the second chamber when pressure fluid is supplied to the first chamber and to accumulate part of the pressure fluid from the second chamber. A pressure booster is connected in hydraulically parallel to the first accumulator, the pressure booster communicative with the second chamber when the pressure fluid is supplied to the first chamber to boost pressure of the pressure fluid by using part of the pressure fluid from the second chamber. A second accumulator accumulates the pressure fluid whose pressure is boosted by the pressure booster.