| 摘要 |
PURPOSE:To reduce the internal leakage of oil and to enable to pass a larger amount of oil, by opening a check poppet through the detection of pilot pressure by means of a pilot valve, and increasing the size of a return passage. CONSTITUTION:When a spool 22 is moved to the right, oil from a pump is passed through a parallel feeder 36 and discharged from an actuator port 21 by forcing a check poppet 38 open. On the other hand, when the spool 22 is moved to the left, a pump port 26 is communicated with a neutral passage 29, and at the same time, pressure is produced when oil from the pump is passed through a restriction 49. When the pilot pressure is introduced into a pilot chamber 33, a spring chamber 39 is communicated with a low-pressure passage 46 through the movement of a pilot valve 32. Resultantly, oil is passed through an orifice 41 and the check poppet 38 is moved by the pressure difference to open a connecting port 37, so that the return oil is passed into the low-pressure passage 46. |
