摘要:
A control valve apparatus includes a second-working-actuator acceleration control valve connected to a first working control valve in parallel. The second-working-actuator acceleration control valve includes pilot chambers receiving a pilot pressure for switching first and second working control valves and a flow channel that guides a pressure fluid of a first pump port to an entrance port side of the second working control valve. The second-working-actuator acceleration control valve is switchable between a first priority position in which a pressure fluid is guided to the first working control valve with a higher priority than the second working control valve and a second priority position in which a pressure fluid is guided to the second working control valve with a higher priority than the first working control valve.
摘要:
A fluid pressure control device includes a switching valve configured to operate in conjunction with the control valve by the pilot pressure led through the pilot valve to switch work of the operation check valve. The switching valve includes a pilot chamber to which the pilot pressure is led, a spool that moves in accordance with the pilot pressure of the pilot chamber, a bias member that biases the spool in the valve closing direction, a collar detachably installed in the pilot chamber, and a piston slidably inserted into the collar, the piston being configured to receive the pilot pressure on a back surface thereof and give thrust force to the spool against bias force of the bias member.
摘要:
Die Erfindung betrifft ein Freigabeventil (15) für ein hydrostatisches Antriebssystem, das einen Steuerdruckanschluss (ST) und einen Lastdruckanschluss (LS) ansteuert, wobei das Freigabeventil (15) eine Funktionsstellung und eine Entlastungsstellung aufweist. Das Freigabeventil (15) ist als doppeltes Druckbegrenzungsventil (20) in Sitzventilbauweise ausgebildet ist, das einen ersten, einen Ventilsitz (26) des Lastdruckanschlusses (LS) ansteuernden Ventilsitzkörper (21) und einen zweiten, einen Ventilsitz (24) des Steuerdruckanschlusses (ST) ansteuernden Ventilsitzkörper (22) aufweist. An dem ersten Ventilsitzkörper (21) ist eine von dem im Lastdruckanschluss (LS) anstehenden Lastdruck beaufschlagte Steuerfläche (30) ausgebildet, die den ersten Ventilsitzkörper (21) in die Entlastungsstellung beaufschlagt, in der der Lastdruckanschluss (LS) zu einem Tankanschluss (T) entlastet ist. An dem zweiten Ventilsitzkörper (22) ist eine von dem im Steuerdruckanschluss (ST) anstehenden Steuerdruck beaufschlagte Steuerfläche (31) ausgebildet, die den zweiten Ventilsitzkörper (22) in die Entlastungsstellung beaufschlagt, in der der Steuerdruckanschluss (ST) zu einem Tankanschluss (T) entlastet ist.
摘要:
A fluid pressure control device includes a switching valve that operates in conjunction with a control valve by a pilot pressure to switch an operation of an operated check valve. The switching valve includes a spool that moves according to the pilot pressure of a pilot chamber, and a piston that is accommodated in the pilot chamber and imparts a thrust force to the spool upon receiving the pilot pressure. The piston includes a first piston that is slidingly accommodated in the pilot chamber and is acted upon by the pilot pressure, and a second piston whose distal end faces the spool and is inserted into an accommodating hole formed in the first piston. A spherical protrusion is provided on a center of either one of a bottom surface of the accommodating hole of the first piston and a back surface of the second piston.
摘要:
A pilot pressure control valve V17 is provided that is switchable between an operation position 56 where pilot pressure is supplied to a first channel switching valve V12 and a non-operation position 57 where pilot pressure is not supplied to the first channel switching valve V12; this pilot pressure control valve V17 is switched to the non-operation position 57 during a state of non-travel and is switched to the operation position 56 with a pilot pressure established in a travel detection circuit 54, and in the operation position 56, supplies a pilot source pressure to the first channel switching valve V12 from a fourth pump P4 on the upstream side of a pressurized oil introduction orifice 53.
摘要:
A hydraulic circuit for a working machine includes hydraulic actuators (9,10) which respectively drive a plurality of kinds of working devices and which are driven by a drive circuit having circuit states that correspond to the working devices, a directional control valve unit (19) which, when one of the working devices is attached to the attachment, switches in response to a signal from a controller (21) to select one of the circuit states, a detection sensor (23) that detects the actual circuit state, and a display (24) operated by the controller. The controller activates the display when the detected actual circuit state and the selected circuit state do not match.