摘要:
The invention relates to a hydraulic cylinder, for use in a hydraulic tool, comprising a hollow cylinder body (8) accommodating a first piston, which first piston is composed of a hollow first piston rod (14), which extends from the cylinder body, and a first piston body (20) connected thereto, said cylinder body and said first piston body defining a first cylinder chamber (21) and said cylinder body, said first piston body and said first piston rod defining a second cylinder chamber (22), as well as a second piston accommodated in the hollow first piston rod, which second piston is composed of a second piston rod (26), which extends through the first piston body and which is connected to the cylinder body, and a second piston body (25) connected thereto, said first piston rod and said second piston body defining a third cylinder chamber (23) and said first piston rod, said second piston rod and said second piston body defining a fourth cylinder chamber (24), wherein the second piston rod is at least provided with a bore that terminates in the third cylinder chamber, and wherein the cylinder chambers can be connected to a first (P1) and a second supply line (P2), respectively, for extending and retracting the first piston rod.
摘要:
Subject-matter of the present invention is a device for the optimization of hydraulically controlled engagement of clutches used in marine transmissions. This device comprises pumps (10) for the delivery of hydraulic fluid from a reservoir (11) to two control pistons (12a, 12b) of said clutches, two solenoid valves (13, 14) arranged between said pumps (10) and said pistons (12a, 12b), a bistable valve (15) arranged in parallel between said solenoid valves (13, 14) and said pistons (12a, 12b), a control valve (16) arranged on the pressure side of said pumps (10) toward the discharge line leading to the reservoir (11) and equipped with an adjusting device (17), whose spring element (18) is linked to said bistable valve (15). The device is characterized in that it comprises a shuttle-type sequence valve (19) for the link between the spring element (18) of said adjusting device (17) and the supply line of said solenoid valves (13, 14) or said bistable valve (15), whereby the bistable valve is also linked to the hydraulic control (20) of said sequence valve (19), and whereby a preset pressure drop is produced between the spring element (18) of said adjusting device (17) and the bistable valve (15), and said adjusting device (17) is linked to the pressure side of said pumps (10).
摘要:
To permit releasing an excessive rod pressure from a first hydraulic cylinder and also effectively using pressure oil of its rod chamber upon performing such an operation that pressure oil is fed to a bottom chamber of a second hydraulic cylinder, a hydraulic drive unit is provided with a boom cylinder 6, an arm cylinder 7, a communication line 40 communicating a rod chamber 6b of the boom cylinder 6 and a bottom chamber 7a of the arm cylinder 7 with each other, and a switching valve 57 arranged on the communication line 40 for communicating or shutting off the communication line 40 in accordance with a rod pressure of the boom cylinder 6. When an arm-crowding single operation is performed and by its digging counterforce, a rod pressure of the boom cylinder 6 rises to a high pressure of at least a predetermined pressure, the switching valve 57 is changed over from a shut-off position to a communicating position to feed pressure oil from the rod chamber 6b of the boom cylinder 6 to the bottom chamber 7a of the arm cylinder 7. The boom cylinder 6 is hence caused to automatically extend, thereby avoiding lifting of a body of a hydraulic excavator.
摘要:
The clutch (1,21) transmits a movement generated by a drive shaft (3,23) to an output shaft (2,22), and the circuit includes at least one proportional-pressure valve (5,12,25) for the fluid and/or gas supplied to a clutch chamber (1,21), actuated in accordance with pressure-control signals (6,13,26) processed by a microprocessor (7,27), and means (4,24) for treating the fluid and/or gas supplied to said proportional pressure valve (5,12,25). It is characterised in that the circuit includes at least one fluid and/or gas proportional-flow valve (9,15,29) actuated in accordance with flow-control signals (11,16,31) processed by a microprocessor (7,27), at least one pressure tank (8,14,28) situated at the outlet from said at least one proportional-pressure valve (5,12,25), and a valve (10,30) connected to the clutch chamber (1,21) to activate filling or draining of the fluid and/or gas, such that the circuit provides at all times the necessary pressure (P) inside the clutch (1,21) to transmit the torque required in accordance with the movement of the output shaft (2,22).
摘要:
There is provided a hydraulic control device for an automatic transmission, which is comprised of an engagement state determining section and a protection control section. If the engagement state determining section determines that each clutch ((H/C,2-4B,L&R/B), which is supplied with a line pressure via a regulating valve (7,10a-10c) having a spool and has an oil pressure switch (13a-13c) disposed in an oil channel, is held in an engaged state when gears are not changed, the protection control section sets a command pressure for the regulating valve to a protective oil pressure lower than the line pressure. This brings the regulating valve into a pressure-regulating state to cause lands of the spool to form apertures that reduce hydraulic vibration applied to the line pressure. This inhibits an oil pressure beyond an acceptable value from being applied to the oil pressure switch, and therefore improves the durability of the oil pressure switch.
摘要:
The invention relates to a device for applying a working force to a workpiece, using a working cylinder (92). Said device comprises a working piston (9), an actuation chamber that can be supplied with a hydraulic medium, a recirculation chamber (86) that can be supplied with a gaseous medium and a force transmission device (5) that co-operates with the working piston (9). This allows a transmission or an application of the working force to a workpiece that is as rapid as possible with a technical construction that is as simple as possible.
摘要:
Es wird eine Ventilanordnung (10) für einen Hydraulikzylinder (26) zum Heben und Senken eines Auslegers (86) an einem Teleskoplader (82) beschrieben. Über eine erste und eine zweite Versorgungsleitung (22, 24) und ein Steuerventil (12) wird eine erste und eine zweite Kammer (28, 30) des Hydraulikzylinders (26) wahlweise mit einer Hydraulikdruckquelle (18) oder einem Behälter (20) steuerbar verbunden. Des Weiteren sind Schaltventile (50, 66) enthalten, welche den Durchfluss in einer zwischen der ersten Kammer (28) und dem Behälter (20) verlaufenden ersten Hydraulikleitung (46) und in einer zwischen der zweiten Kammer (30) und dem Behälter (20) verlaufenden zweiten Hydraulikleitung (62) derart steuern, dass eine Schwimmstellung einstellbar ist. Ferner ist eine Lasthaltevorrichtung (32) enthalten. Zur Absicherung gegen unkontrolliertes Absinken des Auslegers (86) bei Umschalten in Schwimmstellung unter Last ist in der ersten Hydraulikleitung (46) eine volumenstromabhängig steuernde Ventileinrichtung (52) enthalten, die den Volumenstrom begrenzt.