| 摘要 |
<p>PROBLEM TO BE SOLVED: To easily avoid clogging of dust/dirt in a pressure adjusting valve for a clutch in a traveling transmission device operated at speed shift so as to automatically disengage the clutch to be gradually boosted to clutch pressure for transmission. SOLUTION: At speed shift when hydraulic cylinders 11, 12, 13, 14 shift shift gears, check valves 37, 38, 39, 40 of a pilot circuit 34 are opened for connecting mechanisms 37a, 38a, 39a, 40a, and a control valve 34 disengages a clutch 3. At this time, a pressure adjusting valve 35 is operated so that dust/dirt easily falls off by a pulse signal for cleaning. After speed shift, the check valves 37, 38, 39, 40 are closed, and the control valve 34 operates the clutch 3 to the engaging side. At this time, a solenoid proportional pressure adjusting valve 35 is operated by a boosting pulse signal, and the hydraulic clutch 3 is gradually boosted.</p> |
