| 摘要 |
PURPOSE:To improve control precision by increasing or decreasing the maximum allowable current and the minimum operating current applied to a solenoid proportional valve controlling the tilt angle of a pump motor in stages when a hydraulic circuit is inoperative and learning the maximum and minimum tilt angle control current according to the change of the tilt angle at this time. CONSTITUTION:When a pump motor 1 is judged to be inoperative by an MPU 13 based on the output signal of a gear position sensor 5 and the operation state of an electromagnetic clutch 9, the maximum allowable current giving the maximum tilt angle to the pump motor 1 is applied to a tilt angle control proportional solenoid valve 3, and the output of a tilt angle sensor 2 at this time is stored. The tilt angle control current I is decreased by the preset value, the output voltage of the tilt angle sensor 2 at this time is compared with the stored voltage, if they coincide, the control current I is decreased by the preset value, when they differ from each other, the control current I at this time added with the preset value is set and stored as the actual maximum tilt angle control current. The minimum tilt angle control current is likewise set. |
