| 摘要 |
PURPOSE:To eliminate lag of pump action by such a construction that an inverse operation, in case a control valve is operating during acdeleration or deceleration, selects the main circuit on low pressure side and that the pressure of main circuit is led to the control valve as change-over pressure to reinstate it. CONSTITUTION:When the operating lever 10A is restituted to the neutral position during accelerating operation, the pilot pressure signal at the pilot valve 11A becomes zero and the servo valve 6 is set in the change-over position 6B, so that the right-hand oil chamber 5b of the actuator for control 5, is connected to the control oil pressure source 9 through servo 6 and control valve 8 and, then, the selector valve 15A is set in the change-over position 15B to lead the pressure of main circuit B to the control valve 8. Because the pressure of main circuit B is low, the control valve 8 is reinstated to the return position 8B to take full open condition. Accordingly, the actuator for control 5, will move the pushoff volume variable mechanism 4 to the neutral position at the maximum operating speed. Thus lag of the action can be eliminated. |
