| 摘要 |
A hydraulic circuit for straight movement is provided to increase operability and workability while traveling by securing the independent traveling against working devices and preventing equipment from traveling eccentrically or suddenly. The hydraulic circuit for straight movement comprises primary and secondary hydraulic pumps(1,2), a primary traveling control valve and control valves(10~13) for working devices such as a swing, a boom, an option device and an arm installed on a primary center bypass passage(20) of the primary hydraulic pump, a primary center bypass change-over valve(19) installed on the lowermost part of the primary center bypass passage and changed over with signal pressure transferred through a pilot passage(26) from the outside, a secondary traveling control valve(14) and control valves(15~17) for working devices such as a boom, a bucket and an arm installed on a secondary center bypass passage(22) of the secondary hydraulic pump, a straight traveling valve installed on the upper part of the secondary center bypass passage and changed over with signal pressure transferred through a pilot passage from the outside to distribute and supply working oil discharged from the primary and secondary hydraulic pumps to traveling and working devices, a secondary center bypass change-over valve(19a) installed on the lowermost part of the secondary center bypass passage and changed over with signal pressure transferred through a pilot passage(27) from the outside, and a remote control valve supplying and changing over pilot signal pressure discharged from a pilot pump(3) when a driver operates a lever into the primary and secondary center bypass change-over valves and the straight traveling valve. |
