Abstract: A piston for an internal combustion engine and method of construction thereof is provided. The piston has a top part and a bottom part. The top part has an upper combustion surface including a top surface with a combustion bowl recessed therein. An annular combustion bowl rim extends between the top surface and a side wall of the combustion bowl. The bottom part has a bottom wall and a pair of pin bosses depending therefrom. The top part is fixed to the bottom part with an annular cooling gallery defined therebetween. The side wall of the combustion bowl has a radially outwardly facing side bounding a portion of the cooling gallery, wherein an annular recessed channel is formed therein adjacent the combustion bowl rim. A cooling ring is disposed in the annular channel. The cooling ring channels coolant adjacent the combustion bowl rim to facilitate cooling the combustion bowl rim.

Abstract: The Construction machinery includes at least two actuators, a main pump that generates hydraulic energy for driving the actuators, control valves disposed between the main pump and the actuators, a hydraulic pump motor driven by the generator motor that generates energy to be added to the hydraulic energy, and a controller that reduces hydraulic energy generated by the main pump when the hydraulic pump motor driven by the generator-motor generates energy. The construction machinery further comprises changeover valves that selectively change a location at which the energy from the hydraulic pump motor driven by the generator-motor is to be added according to the actuators. The controller changes a reduction rate of the hydraulic energy generated by the main pump depending on a specific actuator to which the energy is to be added.

Abstract: To make it possible to efficiently utilize rated output torque of a prime mover by performing total torque control with high precision through precise detection of absorption torque of another hydraulic pump by use of a purely hydraulic structure and feedback of the absorption torque to the side of one hydraulic pump, delivery pressure of a main pump and a load sensing drive pressure are supplied to a torque feedback circuit, which modifies the delivery pressure of the main pump to achieve a characteristic simulating the absorption torque of the main pump, and outputs the modified pressure. An output pressure of the torque feedback circuit is supplied to a torque feedback piston, which controls displacement of the main pump so as to decrease the displacement of the main pump and thereby decrease maximum torque as the output pressure increases.

Abstract: A hydraulic circuit for a construction machine is disclosed, which can prevent a loss of pressure during a combined work.

Abstract: In a fluid pressure cylinder, a first positioning ring is provided detachably on a first annular projection of a head cover, and a second positioning ring is provided detachably on a second annular projection of a rod cover. Further, a structure is provided in which opposite ends of a cylinder tube are inserted over and capable of being retained on outer circumferential sides of the first and second positioning rings. As a result, by preparing a new cylinder tube having a different diameter, and new first and second positioning rings, and mounting the new cylinder tube through the new first and second positioning rings, which are installed on the first and second annular projections, a fluid pressure cylinder having a different bore diameter can be obtained.

Abstract: A control system for a hybrid construction machine includes first and second main pumps for supplying working oil, a boom cylinder extending by supply of the working oil to a piston-side chamber and raising a boom and contracting by discharge of the working oil from the piston-side chamber and lowering the boom, a regenerative spool valve controlled by a pressure of pilot pressure oil and adjusting a flow rate of the working oil discharged from the piston-side chamber, a regenerative motor for regeneration rotating by the working oil discharged from the piston-side chamber, a rotary electric machine connected to the regenerative motor, and a failsafe switching valve switching with a pressure of a regenerative passage between the regenerative control spool valve and the regenerative motor as a pilot pressure and lowering the pressure of the pilot pressure oil to the regenerative control spool valve so that a flow rate of the working oil discharged from the piston-side chamber is narrowed if the pressure of the

Abstract: A single-way damping plunger cylinder includes a cylinder body (3), a piston rod (4), a piston (6) and a sleeve (2), the piston (6) dividing the cylinder body (3) into a first cylinder chamber (31) and a second cylinder chamber (32), a first end of the first oil passage (40) being communicated with the first cylinder chamber (31) via the second oil passage (41) and a second end of the first oil passage (40) being communicated with the second cylinder chamber (32), the valve (5) movably disposed in the second oil passage (41) to open or close a direct communication of the first and second oil passages (40,41); a damping oil passage (50) defined in the valve (5) to communicate the first oil passage (40) with the second oil passage (41). A forklift is also provided.

Abstract: A pressure accumulator includes a membrane (4) forming a movable separating element between media spaces (6, 8) and made of contiguous layers (16, 18, 20, 22, 24, 26) of different materials. At least one layer of a basic structure (16, 20) has filaments. A gas-tight impregnation (24) is disposed between layers (18) made of an elastomer.

Abstract: A hydraulic driving device includes: a hydraulic motor configured to operate by flushing oil from a hydraulic pump through a high pressure oil passage and a low pressure oil passage; a low pressure selective valve configured to operate in accordance with differential pressure between the high pressure oil passage and the low pressure oil passage, and to discharge the oil in the low pressure oil passage inside a motor case; a tank oil passage configured to connect the inside of the motor case with an oil tank; and a choke throttle provided to the low pressure selective valve or to an oil passage lower than the low pressure selective valve.