| 摘要 |
<p>PURPOSE: To make good operability maintainable by controlling a flow control valve in such a manner that a differential pressure between an inflow side and a discharge side or an inflow side pressure or a discharge side pressure during operating an oil hydraulic motor is generated between MAX/MIN values. CONSTITUTION: Previously MAX/MIN values relating to an absolute value of a differential pressure between an inflow side and a discharge side of a turn motor 3 are left as determined corresponding to each operating amount of an operating lever 61. Since a low control valve 51 is controlled so that a differential pressure during turning the turn motor 3 is generated between the MAX/MIN values, in the case of decreasing the differential pressure, a flow rate is increased, to make drive force surely rise up, so as to enable turning to accelerate. In the case of increasing the differential pressure, a flow rate is decreased to prevent the drive force from rapidly rising up, an rapidly accelerating the turning can be suppressed. By these operations, good operability can be well maintained.</p> |
