摘要:
An oil-pressure cylinder in a crushing device is connected to a crushing jaw via a pivot shaft so that the crushing jaw can open and close. The extension of oil-pressure cylinder causes the crushing jaw to close and crush the object to be crushed. Oil-pressure cylinder has a piston with a greater pressure-receiving area on the head side than on the rod side. An acceleration valve serves to switch the extension/retraction operations of the oil-pressure cylinder. During a rod unloaded interval, beginning when the crushing jaw starts to close and ending when the crushing jaw comes into contact with the object to be crushed, the acceleration valve makes communication between a head-side port and a rod-side port in the cylinder continuous, while the oil path from the rod side to a tank is blocked. The oil from the rod side is made to flow to the head side. This speeds up the movement of the rod in the closing operation during the unloaded interval before the crushing jaw comes into contact with the object being held on a fixed jaw at which time communication of the head-side oil-port with the rod-side oil port is interrupted.
摘要:
A method and an apparatus for controlling the function of all kinds of reciprocatable power machines which are actuated by means of a pneumatic, hydraulic of any other pressure fluid, irrespective if the machines are of rotary or axially operating type, in which the active power stroke is accomplished using full power of pressure fluid against a reciprocatable piston (2) in the active air pressure chamber (10, 12), and in which the reversing of the direction of operation is made by alternatingly supplying pressure fluid to the opposite air pressure chamber (12, 10) of the machine, said valve comprises a valve poppet (6) having several channels providing means (7) for alternatingly placing one of the pressure chambers (10, 12) of the reciprocatable fluid actuated machine (1, 2) under full pressure, means (8) for building up a certain counter pressure in a pressure chamber which is, at the actual moment, inactive, and means (9) for evacuating the pressure from an inactive pressure chamber of the fluid actuated machine.
摘要:
A driving device for a hydraulic motor comprising a directional control valve (21) for supplying pressure oil discharged from a hydraulic pump (20) to a first port (25) or a second port (26) of a hydraulic motor (24) and returning oil returning from the second port or the first port to a tank (27) and a pilot pressure supplying valve (40) for controlling the directional control valve (21) wherein the directional control valve is of a pilot pressure selection type in which the valve is positioned, respectively, at a neutral position A by means of springs (32, 33), at a first position B by virtue of a pressure to a first pressure receiving portion (34), and at a second position C by virtue of a pressure to a second pressure receiving portion (35), wherein when the directional control valve is at the neutral position, the discharged pressure oil is supplied to the first and second ports via check valves (36, 37), when at the first position, the discharged pressure oil is supplied to the first port, while pressure oil at the second port is discharged therefrom into the tank, and when at the second position, the discharged pressure oil is supplied to the second port, while pressure oil at the second port is discharged therefrom into the tank, wherein the pilot pressure supplying valve is positioned at a neutral position F by means of springs (50, 51), and is switched to a first position G and a second position H by first and second drive means (52, 53), respectively, so as to supply pilot pressure to the first and second pressure receiving portions, and wherein when the pilot pressure supplying valve is positioned at the neutral position, the first and second pressure receiving portions communicate with the tank, when at the first position, the first port communicates with the first pressure receiving portion, while the second pressure receiving portion communicates with the tank and when at the second position, the second port communicates with the second pressure receiving portion, while the first pressure receiving portion communicates with the tank.
摘要:
An hydraulic lift system has an actuator (2) connected to an hydraulic circuit, having a pump (31), via a supply line (20). A balanced seated valve (50) is connected between the supply line (20) and a reservoir (33), the valve being controlled by a solenoid (51) and an electric drive unit (40). The drive unit (40) supplies a gradually increasing or decreasing voltage to the solenoid (51) to open or close the valve (50) gradually. The valve has a valve member (170) that is displaceable along its length and has a valve head (174) of frusto-conical shape. A passage (176) along the valve member (170) balances fluid pressure across the valve member. The solenoid (51) has an armature (160) with a pole face (161) that can be displaced towards a fixed pole face (167) to unseat the valve member (170). The pole faces (161 and 167) have complementary frusto-conical surfaces (163) and there is a non-magnetic washer (168) between them.
摘要:
A hydraulic motor driving apparatus which includes a directional control valve (21) for controlledly supplying a discharge pressure fluid from a hydraulic pump (20) into a first port (25) or a second port (26) of a hydraulic motor (24) and for controlledly returning the hydraulic fluid from the second or first port into a tank (27), and a pilot pressure applying valve (40) for controlling the directional control valve, and in which the directional control valve is of a pilot pressure switching type adapted to take its neutral position A with springs (32, 33), to take its first position B under a hydraulic pressure applied to its first pressure receiving portion (34) and to take its second position C under a hydraulic pressure applied to its second pressure receiving portion (35); the discharge pressure fluid from the hydraulic pump is supplied via a check valve (36, 37) into the first and second ports of the hydraulic motor when the directional control valve is at the neutral position; the discharge pressure fluid from the hydraulic pump is supplied into the first port of said hydraulic motor and a hydraulic pressure fluid of said second port is allowed to flow out thereof into the tank, when the directional control valve is at the first position; the discharge pressure fluid from the hydraulic pump is supplied into the second port of the hydraulic motor and a hydraulic pressure fluid of the first port is allowed to flow out thereof into the tank, when the directional control valve is at the second position; the pilot pressure applying valve is adapted to take its neutral position F with springs (50, 52) and to be switched to take its first or second position G or H with a first or second drive unit (52, 53), respectively, to apply a pilot pressure to the first or the second pressure receiving portion of the directional control valve; both of the first and second pressure receiving portions of the directional control valve are each brought into a fluid communication with the tank when the pilot pressure applying valve is at the neutral position; the first port of the hydraulic motor is brought into a fluid communication with the first pressure receiving portion of the directional control valve and the second pressure receiving portion is brought into a fluid communication with the tank, when the pilot pressure applying valve is at the first position; and the second port of the hydraulic motor is brought into a fluid communication with the second pressure receiving portion of the directional control valve and the first pressure receiving portion is brought into a fluid communication with the tank, when the pilot pressure applying valve is at the second position.
摘要:
A hydraulic actuating unit (1) is disclosed, having a positioning motor (2) which is arranged in a diagonal of a bridge circuit (3) having four electromagnetic valves (6, 7, 8, 9), the other diagonal being arranged between a pressure source (4) and a pressure sink (5). In such an actuating element, it is desirable for the response behaviour to be improved. For that purpose, all four electromagnetic valves (6, 7, 8, 9) are in the form of normally-open electromagnetic valves.
摘要:
Es wird eine hydraulische Steuereinrichtung (10) vorgeschlagen, mit der eine lastkompensierte Volumenstromsteuerung beim Heben und Senken eines einfachwirkenden Motors (11) steuerbar ist. In einer Zulaufleitung (18) liegt ein erstes Zwei-Wege-Proportionaldrosselventil (19) und ein die Last absicherndes Rückschlagventil (21), während in einer Ablaufleitung (23) ein zweites Zwei-Wege-Proportionaldrosselventil (24) geschaltet ist, denen in einem gemeinsamen Leitungsabschnitt (26) eine Druckwaage (22) zugeordnet ist. Das erste Proportionaldrosselventil (19) liegt in einem Steuerkreis (31, 32, 35, 40) mit Wechselventil (34) und steuert die Umschaltung der Druckwaagensteuerung, so daß die Druckwaage (22) in beiden Stömungsrichtungen, also bei Heben und Senken, wirksam wird.
摘要:
Die Erfindung betrifft ein Sperrventil, das in mindestens einem Verbraucherkanal eines mit einem Längsschieber ausgestatteten Wegeventils angeordnet ist und in Rückströmrichtung sperrt. Im Körper des Sperrventils sitzt ein ebenfalls in Rückströmrichtung sperrendes Hilfsventil, das zur Einleitung der verbraucherseitigen Verbraucherkanalentlastung über einen vom Längsschieber betätigten Stößel geöffnet wird. Im oder am Sperrventilkörper ist neben dem Hilfsventil ein Druckbegrenzungsventil angeordnet, daß dann öffnet, wenn im verbraucherseitigen Druckmittelstrang der erforderliche Arbeitsdruck um ein vorgegebenes Maß überschritten wird.
摘要:
In a construction machine of a small rotational inertia such as an intra-width swing machine or a small-sized excavator, a rotative operability varies depending on the posture of a working attachment, and in a reduced state of reach, a change in rotating force is oversensitive to the operation of a working lever, so operation is difficult. To cope with this point, means for detecting the operation of a rotating direction control valve is provided and an outlet of a center bypassing oil path in the rotating direction control valve and an oil tank are brought into communication with each other through a cut-off valve used for controlling the bleed-off thereof. Further, a pilot port of the cut-off valve and a source of a pilot oil pressure are brought into communication with each other through an electromagnetic proportional pressure reducing valve, and an operation command signal is issued from a controller to the electromagnetic proportional pressure control valve to control the acceleration of rotation and the maximum rotating speed.
摘要:
A hydraulic system comprises at least one control unit (10,12) and at least one actuator (14) which is connected via conduits (16,18) to the control unit and which can be driven via the latter in reciprocating motion against and with a load acting on the actuator, in particular upwards and downwards against gravity. The system further comprises a pressure-compensating valve (78) for matching the pressure in the conduit (16), which serves as a return conduit during movement of the actuator (14) with the load, to the load pressure by replenishing the return conduit from the feed conduit (18).