| 摘要 |
<p>PURPOSE:To make control responsiveness and controllability so better by performing it to combine the spool opening area control of directional control valve and the pressure control of a variable relief valve together. CONSTITUTION:A detecting means 7 is installed in a manual selector valve 3 where a spool opening area is controlled by an operating lever 31. Output from this detecting means is inputted into a controller 8 controlling a solenoid- operated directional control valve 54 connected to a control part 52 of a relief valve 51 and a solenoid proportional relief valve 55. With this constitution, since pressure control through flow control by opening area control at a low pressure area can be done, control responsiveness is improvable. In addition, since acceleration and deceleration for turning motion can be properly controlled over the whole area of lever operation, controllability becomes so better.</p> |
