Abstract: There is provided a displacement control system for a variable displacement hydraulic pump which has a displacement control piston assembly (6) having a large diameter chamber (7) for operating a displacement control member (5) of the variable displacement hydraulic pump selectively in a direction of smaller displacement and in a direction of larger displacement, first control valve (8) and second control valve (9) for selectively communicating the large diameter chamber of the displacement control piston assembly with a pump discharge line and a tank, the first control valve being placed at a supply position by the pump discharge pressure, and at a drain position by a spring associated with the displacement control piston assembly via a feedback lever, and the second control valve being placed at a first position by the pump discharge pressure for communicating the pump port and the large diameter chamber and at a second position by a load pressure for communicating the pump port and the large diameter chamb

Abstract: In a hydraulic circuit system, when pressurized oil discharged from a single hydraulic pump is supplied to a plurality of actuators: the pressurized oil is supplied to heavily-loaded ones of the actuators at gradually reducing flow rates to reduce a shock, while supplied to lightly-loaded ones of the actuators at gradually increasing flow rates to increase working speeds of these lightly-loaded actuators. The hydraulic circuit system comprises a plurality of directional control valves (2) one of which is provided with pressure-compensated flow control valves (18) each of which is provided with a load lead-in passage having a restriction means (R). In addition, further comprised in the system are: relief valves (22, 22) for relieving the pressurized oil under the influence of load pressure of the actuators (3) operated by the directional control valves (2); a restriction orifice (24) provided in a drain side of each of the relief valves so as to produce pressure therein.

Abstract: This invention has for its aim to provide a hydraulic circuit system arranged such that, even at the time of commencement of drive of a hydraulic actuator with a large inertia, a slow rise in the drive pressure can be achieved, thereby preventing the occurrence of hunting phenomenon. The hydraulic circuit system according to the present invention comprises a plurality of operating valves (15) provided in a discharge conduit (10a) of a hydraulic pump (10), and pressure compensating valves (18) provided in connection conduits between these operating valves (15) and respective hydraulic actuators (16), wherein each of the pressure compensating valves (18) is set at a highest value of load pressures of each of the hydraulic actuators (16), and the displacement of the pump is controlled by a change-over valve (14) adapted to be actuated by the difference between the pump discharge pressure and the load pressure.

Abstract: This invention aims at providing a hydraulic circuit apparatus for supplying pressurized fluid into cylinders for a work implement arranged such that during normal operation of the work implement the flow rate of fluid discharged by a pump is controlled such that the difference between the discharge pressure of the pump and the load pressure is always kept constant, whilst during inching operation of the work implement the flow rate of fluid discharged by the pump is reduced.

Abstract: An operation valve having a pressure compensation valve of relatively simple non-complicated internal body structure. In the valve body, a load pressure introducing passage, a check valve and a restriction are formed inside the spool comprising the operation valve. An intermediate pressure between an inlet pressure and an outlet pressure of the compensation valve which is arranged in the valve body, may be supplied to a pressure receiving section of the pressure compensation valve through an oil hole of the spool. The operation valve with the pressure compensation valve is of simple construction and may be easily manufactured.

Abstract: In the hydraulic apparatus (1) according to a first aspect of the present invention, mid-pressures between the inlet side and outlet side pressures of a first and a second pressure compensating valves (4, 4') are permitted to act on the flow rate decreasing side pressure receiving surfaces (4b, 4b') thereof through first and second mid-pressure supplying means (13, 13'), thereby restraining operational error and malfunction of the pressure compensating valves (4, 4'). In the hydraulic apparatus (20) according to a second aspect of the present invention. when actuating valves are made to assume neutral position, holding pressures of hydraulic actuators (5, 5') are permitted to act on flow rate decreasing side pressure receiving surfaces (4b, 4b') of pressure compensating valves (4), (4') so that spools of the pressure compensating valves are held at compensating position, thereby improving the response of the hydraulic actuators (5, 5') to lever actuation.

Abstract: This invention provides a hydraulic circuit apparatus for operating a work-implement actuating cylinder arranged such that, during an earth compacting operation using a bucket, a work implement or boom is lowered by its own weight, and during other operations, a part of the fluid under pressure in a lifting chamber of the actuating cylinder is supplied together with pressurized fluid discharged by a pump into a lowering chamber to increase the retracting speed of a piston rod in the work-implement actuating cylinder. The apparatus comprises a spool slidably inserted in a valve bore formed in an operating valve body so that it may be moved between a first actuating position, where a second port connected to the lowering chamber is communicated with a second tank port and a first port connected to the lifting chamber is communicated with a first pump port; and a second actuating position, where the second port is communicated with a second pump port and the first port is communicated with a first tank port.

Abstract: This invention provides a hydraulic circuit apparatus arranged such that when each of operating valves is operated suddenly, the stability of each of actuators is improved, and when the operating valves are kept at their neutral positions, the flow rate of fluid discharged by a variable displacement pump is increased to improve the response of the hydraulic circuit, and when the actuators are supplied with pressurized fluid, pressure compensation is made by pressure compensating valves.

Abstract: A hydraulic circuit arranged to prevent the load pressure in one of the hydraulic actuators at the time of starting from becoming abnormally high thereby preventing fluid under pressure from being relieved by the safety valve when a plurality of hydraulic actuators are operated at the same time, wherein the function of one of the pressure compensating valves is temporarily enhanced by introducing the load pressure in the hydraulic actuator so as to supply a large quantity of fluid under pressure to the hydraulic actuator connected to the pressure compensating valve so that the operating speed of the hydraulic actuator can be increased.

Abstract: A pressure compensating type hydraulic valve wherein a pressure compensation can be made according to the movement of the movable portion of a hydraulic actuator, and the movable portion of the actuator can be stopped against load pressure when it is located at its neutral position. This pressure compensating type hydraulic valve is arranged such that a spool (24) is moved in a valve hole (16) so as to allow a first actuating port (21) and a second actuating port (22) connected with pressure receiving chambers (13.sub.1, 13.sub.2), respectively, defined on both sides of a movable portion (13.sub.

Abstract: The described embodiments of the present invention provide DRAM cells, structures and manufaturing methods. In a first embodiment, a DRAM cell with a trench capacitor having a first plate formed as a diffusion on the outside surface of a trench formed in the substrate and a second plate having a conductive region formed inside the trench is fabricated. The transfer transistor is formed using a field plate isolation structure which includes a self-aligned moat area for the transfer transistor. The moat area slightly overlaps the capacitor area and allows for increased misalignment tolerance thus foregoing the requirement for misalignment tolerances built into the layout of the DRAM cell. The field plate itself is etched so that it has sloped sidewalls to avoid the formation of conductive filaments from subsequent conductive layers formed on the integrated circuit.

Abstract: An ignition system of the condensor-discharge type for an internal combustion engine is disclosed which is capable of preventing delay of the ignition position at a high engine speed due to an armature reaction and preventing generation of ignition spark at reverse rotation of the engine without using a signal coil for determining the ignition position.

Abstract: All but the circle drive motor of the implement actuators of a motor grader are divided into two groups each consisting of those which need not be operated simultaneously. The power system has three fixed displacement pumps for driving the circle drive motor via a circle control valve and the two implement actuator groups via respective implement control valve arrangements of carry-over parallel configurations. One of the pumps is connected to the two implement control valve arrangements via a restriction and a flow divider. A first demand valve controls communication between the other two pumps and the implement control valve arrangements in response to the pressure differential across the restriction, maintaining constant fluid flow to the valve arrangements regardless of engine speed or the loads on the implement actuators.

Abstract: A directional change-over valve which has a valve body having connecting surfaces at both sides thereof, a spool slidably inserted into the valve body, a check valve replaceable depending upon utilities thereof, wherein the valve body has a plurality of valve chambers, the central valve chamber is communicated with the hole for mounting the check valve for removably mounting the check valve, passages are provided opening at the connecting surfaces of the valve body in the respective valve chambers, another passages are provided for connecting the interior of the check valve to the both side valve chambers to form parallel, tandem and series circuits. Thus, this invention simplifies the structure and circuits to provide a compact directional change-over valve device as a whole.