| 摘要 |
PURPOSE:To decrease loss of an oil pump by adjusting the line pressure in accordance with a throttle pressure and a change gear ratio and enlarging the effects of changes in the change gear ratio on the line pressure on the small change gear ratio side compared with the large change gear ratio side. CONSTITUTION:A throttle valve 504 has a line pressure of an oil passage 534 as an initial pressure and outputs its throttle pressure to an oil passage 538. When a change gear ratio is larger than a specified value, the line pressure becomes high with increasing the throttle pressure. And the line pressure becomes high with increasing the change gear ratio. On the other hand, when the change gear ratio becomes below the specified value, the throttle pressure becomes equal to the line pressure because a theoretical value of the throttle pressure becomes above the line pressure. As a result, the line pressure receiving area of a line pressure governor valve 502 is reduced and the line pressure greatly changes so as to maintain a balancing condition relative to the changes in the change gear ratio. Namely, the change gear ratio becomes smaller on the small change gear ratio side, so that the line pressure becomes lower. Thus, an oil hydraulic characteristics approximate to a theoretically required line pressure can be obtained. |
