Motors: expansible chamber type – With motive fluid valve – Relatively movable inlet and exhaust valves for single...
Patent
1989-10-17
1991-10-15
Look, Edward K.
Motors: expansible chamber type
With motive fluid valve
Relatively movable inlet and exhaust valves for single...
91461, 91462, F15B 1108
Patent
active
050564153
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a control valve system for supplying a pressure oil to hydraulic devices such as hydraulic cylinders, hydraulic motors and the like to control that hydraulic equipments in operation, and, more particularly, to a pilot operated control valve system for conducting the directional controls of a plurality of valves of the system by means of pilot pressure oil and for performing a so-called support function in which a pair of hydraulic motors simultaneously supply the pressure oil to the valves of the system through the same hydraulic circuit.
DESCRIPTION OF THE PRIOR ART
Hitherto, it is known that, for example, as shown in FIG. 1, in a control valve system of this kind: a pressure oil discharged from a hydraulic pump 1 is supplied to a first chamber 3.sub.1 and a second chamber 3.sub.2 of a hydraulic device 3 through a first meter-in valve 2.sub.1 and a second meter-in valve 2.sub.2, respectively. The meter-in valves 2.sub.1, 2.sub.2 being two-way valves; the pressure oil having entered the first chamber 3.sub.1 and the second chamber 3.sub.2 is discharged into a tank 5 through a first meter-out valve 4.sub.1 and a second meter-out valve 4.sub.2, respectively, the meter-out valves 4.sub.1, 4.sub.2 being two-way valves. In case that both the first meter-in valve 2.sub.1 and the second meter-out valve 4.sub.2 are opened, the pressure oil is supplied to the first chamber 3.sub.1 of the hydraulic equipment 3, while the pressure oil having entered the second chamber 3.sub.2 of the equipment 3 is discharged from the second chamber 3.sub.2 of the equipment 3 into the tank 5. In case that both the second meter-in valve 2.sub.2 and the first meter-out valve 4.sub.1 are opened, the pressure oil is supplied to the second chamber 3.sub.2 of the hydraulic equipment 3, while the pressure oil having entered the first chamber 3.sub.1 of the hydraulic equipment 3 is discharged therefrom into the tank 5.
In addition, a pilot operated control valve system is known, in which each of the valves described above is constructed of a pilot operated valve and further comprises a first and a second pilot valve, which first pilot valve conducts directional controls of the first meter-in valve 2.sub.1 and the second meter-out valve 4.sub.2, and which second pilot valve conducts directional controls of the second meter-out valve 2.sub.2 and the first meter-out valve 4.sub.1.
On the other hand, in a power shovel, there are employed at least six hydraulic devices comprising: a boom derricking cylinder, an arm hydraulic cylinder, a bucket hydraulic cylinder, a swing hydraulic motor, a left-hand traveling hydraulic motor and a right-hand traveling hydraulic motor, to which hydraulic devices the pressure oil is supplied through four valves. As a result, the power shovel requires at least 24 valves and 12 pilot valves in operation.
In addition, in a construction-machine vehicle, such as the power shovel provided with the boom derricking cylinder and the arm hydraulic cylinder, it is often required for an operator of the vehicle to simultaneously operate these two hydraulic cylinders in different kinds of operation. In this case, since it is impossible for a single hydraulic pump to simultaneously supply a sufficient quantity of the pressure oil to these hydraulic cylinders, it is necessary to employ a well-known hydraulic circuit system performing a so-called support function in which at least a pair of hydraulic pumps are employed to simultaneously supply a sufficient amount of the pressure oil to a plurality of hydraulic devices through the same hydraulic circuit.
In instances where the pressure oil is supplied to each of the hydraulic devices of the above well-known hydraulic circuit system through four valves, it is necessary to employ a first and a second hydraulic pump. In addition, it is required for the second hydraulic pump to employ a first and a second auxiliary meter-in valve and a first and a second auxiliary pilot valve. As described above, in instances where the pilot ope
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Ishizaki Naoki
Karakama Tadao
Oda Yosuke
Kabushiki Kaisha Komatsu Seisakusho
Kananen Ronald P.
Look Edward K.
Mattingly Todd
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