| 摘要 |
PURPOSE:To enable the shock of speed change to be prevented by a simple hydraulic control circuit, by reducing the line pressure of hydraulic oil for a determined time by means of the control signals from a speed change control part to a lower level of pressure where one side friction member can still maintain its engaging state. CONSTITUTION:For instance, in the case of shifting up from 1st speed to 2nd speed, 1st brake 23, which is one of friction members, is shifted from the open state to the engaging state, while 1st clutch 20, the other friction member, is still maintaining its engaging state. In this speed change, the line pressure of hydraulic oil is reduced by the signal from the speed change control part for a determined time to a certain level of pressure which is within the range where the pressure is sufficient to maintain the engaging state of said 1st clutch 20. Due to the above construction, speed change can be accomplished in a determined timing while appropriately controlling the line pressure of the hydraulic oil for the other friction member without provision of an accumulator, thus enabling the shock of speed change to be prevented by a simple hydraulic control circuit. |
