| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a control device for automatic transmission capable of avoiding a shift shock caused by rack slipoff, etc., even if the friction coefficient of a drum brake does not show a proper value in the case of one speed to two speed shifting, etc., in which a band brake is engaged. SOLUTION: Automatic transmission is equipped with a band brake as a friction element for shifting and an AT control unit 4 to perform the shift control on the basis of the operating point determined at least from the car speed and the degree of throttle opening and the shift map, wherein the arrangement further includes an oil temperature sensor 9 to sense the oil temperature in the transmission and a shift frequency counter 5 to sense the shifting frequency from one speed to two speed stage conducted by engagement of the band brake, and the AT control unit 4 is equipped with a preliminary engagement control part 4a to put the band brake in preliminary slip engagement when the operating point lies within the band brake preliminary engagement control region set in the region of one speed stage, the sensed oil temperature lies under the preset oil temperature, and the sensed shifting frequency is below the preset value.</p> |
