| 摘要 |
PURPOSE:To prevent the generation of such a situation as to be out of travel due to an engine stalling even in the case of failure being generated by forming a hydraulic circuit for placing lock-up mechanism forcibly into the released state when a change gear ratio command member is placed in the position of commanding a change gear ratio larger than the specified value. CONSTITUTION:When the change gear ratio commanded to a step motor 152 becomes larger than the specified value, a change gear ratio command member, positioned as shown at the right half part in the drawing, communicates an oil passage 551 with an oil passage 540. The constant pressure of the oil passage 540 is thereby supplied to the oil passage 551. Because of this constant pressure acting upon a lock-up control valve 508, the lock-up control valve 508 is placed in the state as shown on the left half side in the drawing so as to release a lock-up clutch. In this state, an oil passage 553 is cut off whatever oil pressure is outputted to the oil passage 553 from a lock-up solenoid 526, so that there is no influence on the lock-up control valve 508. |
