| 摘要 |
PURPOSE:To immediately stop down motion of a propulsive unit, by a method wherein, during a stop after tilt down control, a working oil pressure in a control line is bled to the short line side through a communicating passage. CONSTITUTION:During control of tilt down, the working oil pressure of a pump 33 is exerted on a control line 64, and a second chamber 22 of a tilt cylinder 18 is communicated through a short line 53 to a resevoir 31. This enables a discharge flow rate of working oil fro the second chamber 22 to exceed a delivery flow rate of the pump 33. During a stop after control of tilt down of the hydraulic pump 33, a working oil pressure within a control line 64 is bled to the short line 53 side through a communicating passage 63. This increase the return speed of a shuttle piston 55 to increase the closing motion speed of a first check valve 56, resulting in a stop of outgoing of working oil within the second chamber 22 of the tilt cylinder 18. |
