400 Commonwealth Drive, Warrendale, PA 15096-0001 U.S.A. Tel: (724) 776-4841 Fax: (724) 776-5760 Web: www.sae.org SAE TECHNICAL PAPER SERIES 2006-01-0847 Toyota’s New Six-Speed Automatic Transaxle U660E for FWD Vehicles Daisuke Kusamoto, Yuji Yasuda, Kazuyuki Watanabe, Hiromichi Kimura and Akira Hoshino Toyota Motor Corp. Reprinted From: Tran smission and Driveline 2006 (SP-2001) 2006 SAE World Congress Detroit, Michigan April 3-6, 2006 Downloaded from SAE International by Univ of California Berkeley, Friday, July 27, 2018The Engineering Meetings Board has approved this paper for publication. It has successfully completed SAE's peer review process under th e supervision of the session organi zer. This process requires a minimum of three (3) reviews by industry experts. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. For permission and licensing requests contact: SAE Permissions 400 Commonwealth DriveWarrendale, PA 15096-0001-USAEmail: [email protected]: 724-772-4028 Fax: 724-776-3036 For multiple print copies contact: SAE Customer Service Tel: 877-606-7323 (inside USA and Canada)Tel: 724-776-4970 (outside USA)Fax: 724-776-0790Email: [email protected] ISSN 0148-7191 Copyright © 2006 SAE International Positions and opinions advanced in this paper are those of the author(s ) and not necessarily those of SAE. The author is solely responsible for the content of th e paper. A process is available by which discussions will be printed with the pap er if it is publishe d in SAE Transactions. Persons wishing to submit papers to be considered for presentation or publicat ion by SAE should send the manuscript or a 300 word abstract to Secretary, Engineering Meetings Board, SAE. Printed in USADownloaded from SAE International by Univ of California Berkeley, Friday, July 27, 2018ABSTRACT Toyota Motor Corporation has developed a new six- speed automatic transaxle (U660E) for Front Wheel Drive (FWD) vehicles. Component parts of U660E are completely redesigned. By combining an innovative gear train which Toyota originally invented and newer technologies, U660E has achieved outstanding fuel economy, smooth and quick shift performance and quietness in a lightweight package among Automatic Transaxles (AT) with similar torque capacity. INTRODUCTION In recent years, environmental issues such as reducing carbon dioxide emissions and a sudden rise in fuel prices have become increasingly important. They demand automakers to make vehicles which have superior fuel efficiency and cleaner exhaust gases. It becomes more important and essential to meet these requests while improving basic performance characteristics like acceleration time and NVH in vehicle development. As the solution for these requirements, Toyota has developed a new six-speed AT (U660E). This transaxle is installed in the new Camry and Lexus ES. Figure 1 shows a relationship between Toyota’s AT for FWD vehicles and engine torque. AT have been developed not only to adapt to an increase in engine torque but also to appeal to more customers and obtain better fuel economy by increasing from 4 speeds to 5 speeds. U660E is a New Generation 6-speed AT capable of handling a higher torque and offering greater satisfactions compared to the former 5-speed AT (U151E). U660E adopts a compact and efficient gear train which Toyota originally invented. This gear train structure consists of two clutches and three brakes combined with a Ravigneaux gear set and one simple planetary gear set. By combining the gear train with new technologies such as an increase in lock-up and flex lock-up range, new coast down shift control and lower drag friction discs, U660E achieves an outstanding fuel consumption among comparable ATs. The fuel economy of the vehicle is improved by 7% or m