400 Commonwealth Drive, Warrendale, PA 15096-0001 U.S.A. Tel: (724) 776-4841 Fax: (724) 776-0790 Web: www.sae.org SAE TECHNICAL PAPER SERIES 2007-01-4256 Analysis of Variations in Backlash Between Ring Gear and Planets in a Hub Reduction Axle V. Janardhanan and Mohan V. Kher Tata Motors Commercial Vehicle Engineering Congress and Exhibition Rosemont, Illinois October 30-November 1, 2007Reprinted From: Commercial Vehicle Chassi s & Suspension Systems and Effect of Tire, Suspension & Chassis Failure on V ehicle Dynamics and Control (SP-2146) Downloaded from SAE International by Univ of California Berkeley, Saturday, August 04, 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 © 2007 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, Saturday, August 04, 2018Copyright © 2007 SAE International ABSTRACT This paper presents a simple diagnostic tool / method to identify the causes of variations in measured backlash between the ring gear and its planets in a hub reduction axle. This tool can identify the influence of the parameters such as ring gear ovality / eccentricity with respect to hub axis, accuracy of planet pinion bore position on bell-housing-carrier with respect to hub axis and hub play. This tool eliminates the need of complex and time consuming measurement methods to identify these individual parameters. INTRODUCTION Prototype Hub reduction axle (Figure 1 shows a schematic section of the hub end of hub reduction axle) assemblies were observed to have backlash variations of planet to ring gear, which would result in NVH and durability issues. The backlash variations could be caused by the ring gear and adaptor assembly or planets or planet carrier assembly or Hub play or a combination of all these. Metrological inspection of individual component/ assembly to identify the root cause/ causes needs considerable time and resources. A simple method/ diagnostic tool was identified using which backlash variations could be traced to the following individual parameters. 1. Hub play 2. Ring Gear ovality/ eccentricity with respect to Hub axis 3. Accuracy of position of Planet pinion bores on Planet Carrier with respect to Hub axis. The findings of the tool were later confirmed by the regular measurement methods. BACKLASH MEASUREMENT PROCEDURE The sun gears and axle shafts are removed from the axle assembly before the start of measurement. A planet is located in the bottom most position (by rotating the bell housing-carrier) of the system and the backlash values are measured for all the planets in their respective positions. The measurements are repeated by locating the every o