| 摘要 |
<p>PROBLEM TO BE SOLVED: To reduce shift shock and pull-in feeling in initial shift during low load engine operation and improve running stability during shifting. SOLUTION: This device has a piston formed in a twin piston structure with a primary piston 33 and a secondary piston 34 and interiorly packaging in a servo unit 26 connected to a stem 27 to grant braking torque to a 2&4 brake 20. When operating pressure with specified transient characteristic is supplied to a 2&4 servo chamber 41 during shift, only the primary piston 33 with a small area of pressure receiving face 33a fastens the 2&4 brake 20 via the stem 27 with weak fastening force of restrained braking torque at a low operating pressure in initial shift and, when the operating pressure is over a specified pressure, the secondary piston 34 in addition to the primary piston 33 is operated to fasten and fix the 2&4 brake 20. In initial shift, the 2&4 brake 20 is fastened with weak fastening force to reduce shift shock.</p> |
