| 摘要 |
<p>PROBLEM TO BE SOLVED: To smoothly start/stop a construction machine, and when it is emergency stopped, prevent generation of noise and impact force. SOLUTION: In two pilot pressure passages 99, 100 connecting a switching valve 95 and a servo valve 96 to respectively interpose throttles 97, 98, bypass passages 101, 102 are respectively connected so as to bypass each throttle 97, 98, a bypass passage switching means 103 capable of switching each of these bypass passages 101, 102 to an interruption or communication condition in accordance with a command signal is interposed. When an emergency stop of a hydraulic motor 53 is performed, the bypass passage switching means 103 is switched to the communication condition, in this way, hydraulic oil bypasses the throttle 97, 98, to be supplied or delivered from the servo valve 96 or switching valve 95, so that a delivery amount of hydraulic oil of a variable displacement pump 52 can be quickly decreased, in this way, generation of noise and impact force can be prevented.</p> |
