摘要:
In a direct drive type hydraulic pump, the displacement of the hydraulic pump is forcedly changed to a desired displacement according to an instruction of a channel different from a usual instruction, thereby changing to a desired displacement quickly with good responsivity. When an emergency brake switch is turned on, an emergency brake signal is entered an emergency brake control valve. Thus, an emergency brake signal pressure is entered a piston through an emergency brake signal oil passage, and a piston is forcedly positioned in a neutral position. In other words, the piston can be forcedly positioned in the neutral position according to the emergency brake signal regardless of the entry of a usual brake signal. Therefore, the displacement of the hydraulic pump can be forcedly changed to the neutral position (minimum displacement).
摘要:
A high versatility can be obtained, the pipe laying can be configured easily and, by virtue of the fact that a pilot pressured oil is managed, a hydraulic apparatus can be compacted. A differential pressure &Dgr;P between a pressure of the pressured oil on an upstream side and a pressure of the pressured oil on a downward side of operation valves is set to a certain value by a front-to-rear differential pressure stabilizer. As a result, flow rates Q1, Q2 of the operation valves are determined univocally in accordance with opening surface areas (opening amounts) A1, A2 of the operation valves, irrespective of load fluctuations, that is to say, a fluctuation of &Dgr;P. When one of operation members are operated, the opening amount A2 of the other operation valve correspondent with the other operation member is changed in accordance with an operation amount S1 of that operation member, and the other hydraulic actuator correspondent with the other operation valve is driven.
摘要:
A fluid-pressure transmitting apparatus that is capable of securing the operationality of a working machine and braking and preventing against engine stall. The apparatus can switch between a working-machine operating device and a traveling operating device. When a second operating unit is operated during operation of a first operating unit, the pilot pressurized oil outputted from each operating means through first and second pilot-pressure admission passages is admitted to a low-pressure selecting valve. At this time, the pilot pressurized oil is automatically selected through the low-pressure selecting valve to control the delivery capacity of the traveling pump and braking and preventing engine stall and realizing travel at low speed.
摘要:
The invention provides a pressure reducing valve in which a minimum pressure can be secured even when an engine speed is reduced. A pressure reducing valve changing an output pressure in correspondence to an engine speed has means for outputting a predetermined minimum pressure when the engine speed is equal to or less than a first predetermined rotational speed.
摘要:
It is an object of the present invention to provide a plural pressure oil energies selective recovery apparatus which can selectively recover pressure oil energies stored in plural pressure oil actuators, based upon recovery conditions. A priority for recovering a return pressure oil from a hydraulic actuator is set in advance for an operation lever of each of the plural hydraulic actuators. If the operation lever is in the non-actuation state at a preceding detection point, the plural pressure oil energies selective recovery apparatus recovers a return pressure oil from a corresponding hydraulic actuator. If the operation lever is in the actuation state, the plural pressure oil energies selective recovery apparatus does not recover a pressure oil.