摘要:
Disclosed is a hydraulic circuit for construction equipment for controlling to selectively supply a hydraulic oil from a hydraulic pump to a hydraulic cylinder for driving a boom. The hydraulic circuit for construction equipment, according to the present invention, comprises: a hydraulic cylinder driven by a hydraulic oil of a hydraulic pump; a direction control valve installed on the oil passage between the hydraulic pump and the hydraulic cylinder; an operating device installed on the oil passage between a pilot pump and the direction control valve; a center by-pass switching valve installed at the most downstream side of a center by-pass passage of the hydraulic pump; a pressure detection sensor that detects the pressure of a hydraulic oil at the large chamber side of the hydraulic cylinder; a jack-up switching valve installed on the oil passage between the operating device and the center by-pass switching valve; and a flow control valve installed in the spool of the direction control valve.
摘要:
To provide a speed controller capable of controlling an action speed of an external cylinder in one stroke in a step-wise manner. The speed controller (1) includes a first flow path (16) and a second flow path (18) that allow a first port (12) and a second port (14) to be in communication with each other. The first flow path (16) is provided with a first check valve (28) for allowing flow from the first port (12) to the second port (14). The second flow path (18) is provided with a first needle valve (32), and an opening hole (28d) of the first check valve (28) is constituted as a part of a flow path. The first needle valve (32) adjusts the flow rate by changing an opening area of the opening hole (28d) with a tip portion (34a) fixed on a piston (30) in the cylinder chamber (20). The speed controller (1) further includes a third flow path (22) allowing the first port (12) and the cylinder chamber (20) to be in communication with each other. The third flow path (22) is provided with a second check valve (46) for allowing flow from the first port (12) to the cylinder chamber (20).
摘要:
A hydraulic drive system includes: a first hydraulic motor (12) and a second hydraulic motor (22) configured to be driven by working oils respectively discharged from a first hydraulic pump (11) and a second hydraulic pump (21) to transmit powers to different drive wheels of right and left drive wheels (2, 3); a first pump control unit (13) and a second pump control unit (23) configured to control discharge volumes and discharge directions of the first hydraulic pump (11) and the second hydraulic pump (21); a signal pressure generating unit (40) configured to generate a signal pressure for adjusting command pressures to control the first pump control unit (13) and the second pump control unit (23) in accordance with the sum of discharge pressures of the first hydraulic pump (11) and the second hydraulic pump (21); and a first pressure adjusting unit (50) and a second pressure adjusting unit (60) configured to adjust the command pressures in accordance with the signal pressure.
摘要:
Valve with in-built pressure threshold detection, mounted in an engine block pipe, the valve comprising a body comprising an electrically insulating external element (16) and an electrically conducting internal element (18) bearing the shutoff-element seat (14), a shutoff element (12), the valve also comprising an electrical terminal (34) connected to a detection system which, with the engine block (4) and the internal element (18), forms an electric circuit, the internal element (18) being in permanent contact with the electrical terminal (34), the internal element (18) sliding in the external element (16) so that, for a pressure below the threshold pressure, the internal element (18) is in electrical contact with the engine block, making the electric circuit, and for a pressure equal to or higher than the threshold pressure, the internal element (18) is not in electrical contact with the engine block, breaking the electric circuit.
摘要:
The invention relates to a hydraulic system comprising a source of high pressure (A), a consumer (C) connectable to the source of high pressure (A) via a flow control valve (21), and a solenoid valve (22) arranged to control the flow control valve (21). The hydraulic system further comprises a hydraulic pilot valve (31) selectively controllable by the solenoid valve (22) to connect a control chamber (28) in the flow control valve (21) either to the source of high pressure (A) or to a low pressure side (T). When the solenoid valve (22) is actuated, the consumer (C) is pre-pressurized via a by-pass conduit prior to the opening of the flow control valve (21). At the same time, the source of high pressure (A) is arranged to act on a first and a second end (32, 33) of the hydraulic pilot valve (31) wherein a spring (36) is arranged to displace the hydraulic pilot valve (31) and connect the control chamber (28) to the low pressure side (T) to open the flow control valve (21).
摘要:
The present disclosure relates to a hydraulic system for a construction machine, and more particularly, to a hydraulic system for a construction machine including a plurality of actuators, in which each of the actuators includes a pump/motor, is operated under a control of a corresponding pump/motor, and stores working oil in an accumulator or receives the working oil supplemented from the accumulator in accordance with a difference between a flow rate entering the actuator and a flow rate discharged from the actuator.
摘要:
A hydraulic valve (1) includes a biasing member (31, 32) for generating a biasing force to press a valve seat (40) and a valve member (51). When a second hydraulic chamber (13B) has higher hydraulic pressure than a first hydraulic chamber (13A), a hydraulic pressure difference between the first and second hydraulic chambers acts on the valve seat (40) to separate the valve seat from the valve member against the biasing force of the biasing member so that the first hydraulic chamber and the second hydraulic chamber come into fluidal communication.
摘要:
An aircraft hydraulic valve (20) includes a housing (30), a check valve (67), a valve opening component (40), and an auxiliary hydraulic pressure supply mechanism (38). The housing includes a first port (31) communicated with a first chamber (11A) of a hydraulic actuator (11), a second port (32) communicated with a switch valve (15) bypass-communicating a second chamber (11B) of the hydraulic actuator with the first chamber (11A), and an oil channel (37) connecting the first and second ports. The check valve interrupts oil flow from the first port to the second port. The valve opening component is configured to open the check valve with pilot pressure supplied from the second chamber. The auxiliary hydraulic pressure supply mechanism obtains hydraulic pressure, for opening the check valve, from a closed hydraulic pressure section (37A), which is defined in the oil channel between the check valve and the first port.
摘要:
Disclosed are a flow control device and a flow control method for a construction machine for preventing the loss of fluid exhausted from a hydraulic pump when a boom and an arm of an excavator are operated in combination. The flow control device for a construction machine according to the present invention includes: an engine; a variable capacity hydraulic pump connected to the engine; a first hydraulic cylinder and a second hydraulic cylinder connected to the hydraulic pump; a first control valve disposed in a center bypass channel of the hydraulic pump, the first control valve, in neutral, returning the fluid exhausted from the hydraulic pump to a hydraulic tank and, when switched, controlling the driving, stopping, and direction change of the first hydraulic cylinder; a second control valve disposed downstream of the center bypass channel of the hydraulic pump, the second control valve, in neutral, returning the fluid exhausted from the hydraulic pump to the hydraulic tank and, when switched, controlling the driving, stopping, and direction change of the second hydraulic cylinder; a regeneration fluid channel for supplementing and reusing fluid returned to the hydraulic tank during a compression stroke of the first hydraulic cylinder, and a regeneration valve disposed in the regeneration fluid channel; and a pressure-compensated flow control valve which is disposed in a meter-in fluid channel of a spool of the first control valve and limits the quantity of working fluid supplied from the hydraulic pump to the first hydraulic cylinder when the first hydraulic cylinder and the second hydraulic cylinder are operated in combination.