Connecting clutch elements to planetary gear trains for automotive automatic transmissions via coded sketches

This article presents a synthesis procedure to find feasible clutch layouts for a given planetary gear train clutching sequence. The method of constructing coded sketches for a planetary gear train is first introduced. In a coded sketch, all coaxial links, excluding the output link, are arranged in a specific order called a coaxial-link sequence. Based on the coaxial-link sequence, each link is encoded with three codes: x-code, y-code, and xy-code. Two identification rules are then concluded by examining these codes. Rule one tells how to arrange a band clutch without passage interference. Rule two is used to knock out the invalid clutching sequences leading to infeasible clutch layouts. According to the proposed coded sketches and rules, a synthesis procedure is then established for the purpose of finding all feasible coded layouts in a logical way from a given clutching sequence. Coded layouts can be directly and easily transferred to general clutch layouts. Two examples are used to demonstrate the feasibility of the synthesis procedure.