| 摘要 |
<p>A revolution control device comprises a hydraulic pump, a revolution hydraulic motor driven by pressure oil discharged from the hydraulic pump, a control valve for controlling the flow of pressure oil fed from the hydraulic pump to the revolution hydraulic motor and closing a pair of ports communicating with the inlet and outlet ports of the hydraulic motor during the period of neutral position, a valve device for providing or cutting off fluid communication between two pipe lines respectively connected to the outlet and inlet ports of the revolution hydraulic motor, pressure detectors for respectively detecting the pressures in the two pipe lines and producing pressure signals, an rpm detector for detecting a physical quantity based on the rpm of the revolution hydraulic motor and producing an rpm signal, a mode selector for selecting a neutral brake mode and a neutral free mode, and a controller for controlling the driving of the valve device in such a manner as to close the two pipe lines when the neutral brake mode is selected and to provide communication between the two pipe lines on the basis of the pressure signal and rpm signal when the neutral free mode is selected.</p> |
