400 Commonwealth Drive, Warrendale, PA 15096-0001 U.S.A. Tel: (724) 776-4841 Fax: (724) 776-5760 SAE TECHNICAL PAPER SERIES 981099 The Effect of Friction Modifiers on the Low-Speed Friction Characteristics of Automatic Transmission Fluids Observed with Scanning Force Microscopy Carlton G. Slough, Hiroko Ohtani, Mark P. Everson and Donald J. Melotik Ford Motor Company Reprinted From: 1998 Transmission and Driveline Systems Symposium: New Developments and Advanced Concepts in Systems and Components (SP-1324) International Congress and Exposition Detroit, Michigan February 23-26,1998Downloaded from SAE International by University of New South Wales, Monday, August 27, 2018The appearance of this ISSN code at the bottom of this page indicates SAE’s consent that copies of the paper may be made for personal or internal use of specific clients. This consent is given on the condition, however, that the copier pay a $7.00 per article copy fee through the Copyright Clearance Center, Inc. Operations Center, 222 Rosewood Drive, Danvers, MA 01923 for copying beyond that permitted by Sec- tions 107 or 108 of the U.S. Copyright Law. This consent does not extend to other kinds of copying such as copying for general distribution, for advertising or promotional purposes, for creating new collective works, or for resale. SAE routinely stocks printed papers for a period of three years following date of publication. Direct your orders to SAE Customer Sales and Satisfaction Department. Quantity reprint rates can be obtained from the Customer Sales and Satisfaction Department. To request permission to reprint a technical paper or permission to use copyrighted SAE publications in other works, contact the SAE Publications Group. No part of this publication may be reproduced in any form, in an electronic retrieval system or otherwise, without the prior wri tten permission of the publisher. ISSN 0148-7191 Copyright 1998 Society of Automotive Engineers, Inc. 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 discussions will be printed with the paper if it is pu blished in SAE Transactions. For permission to publish this paper in full or in part, contact the SAE Publications Group. Persons wishing to submit papers to be considered for presentation or publication through SAE should send the manuscript or a 30 0 word abstract of a proposed manuscript to: Secretary, Engineering Meetings Board, SAE. Printed in USAAll SAE papers, standards, and selected books are abstracted and indexed in the Global Mobility DatabaseDownloaded from SAE International by University of New South Wales, Monday, August 27, 20181981099 The Effect of Friction Modifiers on the Low-Speed Friction Characteristics of Automatic Transmission Fluids Observed with Scanning Force Microscopy Carlton G. Slough, Hiroko Ohtani, Mark P. Everson and Donald J. Melotik Ford Motor Company Copyright © 1998 Society of Automotive Engineers, Inc. ABSTRACT The effect of friction modifiers on the low-speed frictional properties of automatic transmission fluids (ATFs) was investigated by scanning force microscopy (SFM). A clutch lining material was covered by a droplet of test ATF, and a steel tip was scanned over the sample. The scanning speeds were varied from 0.13 to 8.56 mm /sec, and the frictional force was deduced from the torsion of the SFM cantilever. A reduction in dynamic friction due to the addition of the friction modifier was clearly observed over the entire speed range. This indicates that the boundary lubrication mechanism is dominant under this condition, and therefore surface-active friction modifiers can effectively improve the frictional characteristics. The friction reduction was more pronounced at lower sliding speeds. Thus addition of friction modifiers produced a more positive slope in the µ−ν (friction vs. sliding speed) plots,