摘要:
An apparatus for supplying a pressure oil to a plurality of hydraulic cylinders of a working machine such as power shovels provided with working equipment such as shovels, wherein the cylinders are contracted at the same speed to move down or lower the working equipments at the same speed, so that the working equipment are prevented from suddenly dropping off in operation even if pressure oil passages (a, b) supplying the pressure oil to the cylinders are damaged during operation. The apparatus comprises: a lock valve assembly (B) provided with a valve housing (70) mounted on a cylinder tube of each of the hydraulic cylinders, in which valve housing (70) a check valve (77), a poppet valve (78) and a pilot valve (79) are mounted; and a directional control valve assembly (C) for selectively supplying the pressure oil to a lifting-movement pressure chamber (9a) and a lowering-movement pressure chamber (9b) of each of the hydraulic cylinders through the pressure oil passages (a, b), respectively.
摘要:
A flow control valve assembly, for preventing the pressure oil confined in an inlet port of a valve housing from pulsating and for additionally performing a safety valve function without employing a separate safety valve, has a valve housing which is easy in machining thereof and neat in construction. In the valve housing of the flow control valve assembly is formed a valve-receiving bore (21) in which a poppet (32) and a second spool valve (51), serving as a safety valve, are axially aligned with each other in series. In the valve housing (20), a hydraulic operating oil flows to a communication port (39) of the poppet (32) through an inlet port (23) formed in the valve housing (20), and then further flows to a back-pressure chamber portions (38a, 38b) of the poppet (32) through a variable orifice (44). The pressure oil, having been received in the back-pressure chamber portion (38b), flows out of the portion (38b) to an outer peripheral portion of the second spool valve ( 51). On the other hand, the pressure oil confined in the inlet port (23) flows to a pressure-receiving chamber (56) of the second spool valve (51).
摘要:
A poppet valve device according to the present invention is adapted to sequentially operate a plurality of poppet valves the switching operation of a pilot valve, for example, an electromagnetic solenoid or the like which operates in response to an external input signal. The above-mentioned poppet valve device includes first and second poppet valves (A, B) each of which is constructed so that a poppet (32) for communicating or intercepting an inlet port (30) and an outlet port (31) with or from each other may be moved towards a communicating position by an inlet port side pressure acting upon its pressure receiving portion (32a). The poppet (32) may be moved towards an intercepting position by a pressure acting upon its back pressure chamber (38a, 38b). A pilot valve (c) connects the respective back pressure chambers of these poppet valves to a tank (2) and includes a variable choke portion controlled by an external input signal so that the pressures at the respective back pressure chambers, when the respective poppets of the respective poppet valves are moved to the positions for communicating the respective inlet ports with the respective outlet ports, may be different from each other.
摘要:
A pressure control system in which a pressure in a back pressure chamber of a flow control valve is controlled according to a throttle opening of a pilot valve to locate stationary the valve body of the flow control valve at a position corresponding to the throttle opening of the pilot valve. In the system, a fixed throttle is provided in an oil passage extended to the back pressure chamber of the flow control valve, thereby applying a dampering action to the valve body.
摘要:
A pressure control system in which a pressure in a back pressure chamber of a flow control valve is controlled according to a throttle opening of a pilot valve to locate stationary the valve body of the flow control valve at a position corresponding to the throttle opening of the pilot valve. In the system, a fixed throttle is provided in an oil passage extended to the back pressure chamber of the flow control valve, thereby applying a dampering action to the valve body.
摘要:
Simultaneous operation efficiency in a case where a plurality of actuators are operated by one or a plurality of hydraulic pumps is improved. A delivery pressure passage (1a) of one hydraulic pump (1) and that (1a) of the other hydraulic pump (1) communicate with each other through a first short-circuit passage (39) via a pair of check valves (38, 38), and an unload valve (40) is provided in this first short-circuit passage (39). The load pressure introduction passages (6, 6) on the left and right hydraulic pumps (1, 1) communicate with each other through a second short-circuit passage (36) via a pair of check valves (35, 35), and a relief valve (37) is provided in this short-circuit passage (36). The unload valve (40) is unloaded by the differential pressure between the pump delivery pressure in the first short-circuit passage (39) and the load pressure in the second short-circuit passage (36), whereby a single relief valve (37) carries out a relieving operation both at the time of flow merging and at the time of flow branching to equalize the maximum pump delivery pressures. The set pressure of the relief valve (37) can be a high level so as to relieve the valve (37) under a predetermined high load pressure, whereby the relieving operation can be arbitrarily controlled.
摘要:
In a control valve system provided with a plurality of valves for controlling a hydraulic equipment such as hydraulic cylinders, there are employed a plurality of valves each of which does not interfere with each other in operation and requires a minimum mounting space in the system to enable the system to be a small-sized system having a construction easily adapted to control a plurality of hydraulic equipments. The control valve system comprises: a valve (10) assuming a rectangular parallelepiped form; a first (11) and a second (12) pump port passage formed in an upper portion of a valve housing of the valve (10) so as to be parallel to each other; a tank port passage (13) formed in a lower central portion of the valve housing; a first (14) and a second (15) port passage vertically formed in the valve housing so as to separately open into an upper surface of the valve housing to communicate with each of pressure chambers of the hydraulic equipment; and a plurality of valves (19, 20, 23, 24) inserted into a plurality of valve receiving bores formed in the valve housing so as to shut off desired ones of these port passages from the remaining port passages.
摘要:
In a pilot operated control valve system provided with a plurality of valves for controlling a plurality of hydraulic devices such as hydraulic cylinders, there is employed a plurality of valves each of which does not interfere with each other in operation and requires a minimum mounting space in the system to enable the system to be a small system having a construction easily adapted to control a plurality of hydraulic devices and also adapted to simultaneously supply the pressure oil to the hydraulic devices from a pair of hydraulic pumps through the same hydraulic circuit as needs require.
摘要:
In a pilot operated control valve system provided with a plurality of valves for controlling hydraulic equipment such as hydraulic cylinders, there are employed a plurality of valves each of which does not interfere with each other in operation and requires a minimum mounting space in said system to enable said system to be a small-sized system having a construction easily adapted to control a plurality of hydraulic equipments. The control valve system comprises: a valve (10) assuming a rectangular parallelepiped form; a first (11) and a second (12) pump port passage so formed in an upper portion of a valve housing of said valve (10) as to horizontally and parallelly extend to each other and as to communicate with a hydraulic pump; a tank port passage (13) formed in a lower central portion of said valve housing; a pilot tank port passage (25) so formed ina central portion of the valve housing as to communicate with a drain tank; a first (14) and a second (15) port passage vertically formed in said valve housing so as to separately open into an upper surface of said valve housing to communicate with each of pressure chambers of said hydraulic equipment; a plurality of valves (19, 20, 23, 24) inserted into a plurality of valve receiving bores formed in said valve housing so as to shud off desired ones of these port passages from said remaining port passages; and pilot valves for supplying the pilot pressure oil to these valves.
摘要:
A multiple valve includes first and second valve units respectively having first and second valve bodies. The first and second valve bodies have respective spool bores therein; and a respective spool is inserted in the spool bore of each of the first and second valve bodies. The first and second valve bodies of the first and second valve units also have inlet ports, tank ports, and first and second blocks having mounting holes, the blocks and a respective valve body being fixedly coupled together by means of stud bolts. The first block has a first threaded hole on one side surface thereof for receiving the stud bolt, and a second threaded hole on another side surface thereof for receiving a cover bolt. A pump passage, a main passage and a tank passage extend between the one side surface and the another side surface of the first block, and a stud bolt extends through the second block and is engaged with the first threaded hole. A cover is fixedly mounted on the another side surface of the first block by a cover bolt which is engaged with the second threaded hole, the cover having a cut-out groove therein for communicating the pump passage with the main passage.