| 摘要 |
<p>PURPOSE:To improve the working efficiency by providing a circuit pressure guarantee means which makes surplus pressure oil flow out downstream while guarantee pressure for melting a proportion signal is being retained upstream, according to the proportions signal from a controller. CONSTITUTION:The operation signals P1 or P2, P3 of hydraulic changeover valves 5, 6 are inputted into a controller 20 so that a turning motor 10 and an arm cylinder 11 may be operated simultaneously. Next, the controller 20 outputs a signal that is proportional to the intensity of the operation signal of the changeover valve 5 for the motor 10, and guarantees the pressure upstream of a circuit pressure guarantee means 17 as a pressure proportional to its signal, and makes any surplus pressure oil flow into the cylinder 11 from the lower stream side. Next, the extending operations of the motor 10 and a boom cylinder 14 are conducted simultaneously, and then, operation signals P1 or P2, P4 are inputted into the controller 20. In addition, the controller 20 outputs signals proportional to the intensity of the operation signals P1 or P2, P4 until a predetermined signal value is attained, and guarantees the operation pressure of the motor 10, and forces surplus pressure oil to flow into the cylinder 14.</p> |
