400 Commonwealth Drive, Warrendale, PA 15096-0001 U.S.A. Tel: (724) 776-4841 Fax: (724) 776-5760 Web: www.sae.org W ear Test Method for Developing Plastic Materials for Applica tions Wherein a Plastic Part is Rotating or Reciprocating Against a Nancy Zeng General Motors Corporation Reprinted From: Transmissions and Drivelines Symposium–4WD/AWD (SP-1979) 2005 SAE World Congress Detroit, Michigan April 11-14, 2005 SAE TECHNICAL PAPER SERIES2005-01-0876 Metal SurfaceDownloaded from SAE International by Big Ten Academic Alliance, Wednesday, August 01, 2018The Engineering Meetings Board has approved this paper for publication. It has successfully completed SAE’s peer review process under the supervision of the session organizer. This process requires aminimum 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] Tel: 724-772-4028 Fax: 724-772-4891 For multiple print copies contact: SAE Customer ServiceTel: 877-606-7323 (inside USA and Canada)Tel: 724-776-4970 (outside USA)Fax: 724-776-1615Email: [email protected] ISSN 0148-7191Copyright © 2005 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 the paper. A process is available by which discussionswill be printed with the paper if it is published in SAE Transactions. Persons wishing to submit papers to be considered fo r presentation or publication by SAE should send the manuscript or a 300 word abstract to Secretary, Engineering Meetings Board, SAE.Printed in USADownloaded from SAE International by Big Ten Academic Alliance, Wednesday, August 01, 2018 INTRODUCTION ABSTRACT Engineering plastic materials have been widely used for thrust washer and dynamic (rotary) seal applications in automatic transmissions. Material selection, engineering design (including fuctionality and ease of assembly) and manufacture quality are the most critical factors that affect the performance of the components. The wear test introduced in this paper can be used to determine and rank PV (pressure time velocity) capability of plastic materials for applications where a plastic part is rotating or reciprocating against a metal surface. It provides an ac celerated test method to evaluate the wear performanc e of plastic materials. A single test can provide tribological information at multiple PV conditions. The tribological information obtained from this method includes coefficient of friction, PV (pressure times velocity) limits, and interface temperature profile. This test is currently used by General Motors Corporation to develop plastic materials for transmission thrust washer and dynamic seal applications. Both thrust washer and dynamic (rotary) seal applications are featured as one component rotating rapidly (up to 7000 rpm) against another one with or without axial loads. For thru st washer applications, axial loads are expected but varied from application to application. Incidental dry conditions due to lack of lubrication would not be surprising. The maximum PV (pressure time velocity) condition for some of the thrust washer applications could be beyond 1,000,000 psi- ft/min. The test is running in two sequences (A & B), capable of a PV range from 50,000 psi-ft/min 500,000 psi-ft/min, under dry conditions. The PV steps in sequence A are combinations of high pressure and low velocity -- for applications where high loads are expected, such as thrust washers. Those in sequence B are combinations of low pressure and high velocity -- for applica