1、_SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising theref
2、rom, is the sole responsibility of the user.”SAE reviews each technical report at least every five years at which time it may be revised, reaffirmed, stabilized, or cancelled. SAE invites your written comments and suggestions.Copyright 2016 SAE InternationalAll rights reserved. No part of this publi
3、cation 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.TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada)Tel: +1 724-776-4970 (out
4、side USA)Fax: 724-776-0790Email: CustomerServicesae.orgSAE WEB ADDRESS: http:/www.sae.orgSAE values your input. To provide feedback on thisTechnical Report, please visithttp:/standards.sae.org/ARP5448/5AAEROSPACERECOMMENDED PRACTICEARP5448/5 REV. AIssued 2003-03Reaffirmed 2010-06Revised 2016-11Super
5、seding ARP5448/5Plain Bearing No-Load Rotational Breakaway Torque MeasurementRATIONALEThis revision updates document formatting and document references to align with the latest publications.1. SCOPEThis test method provides a procedure for measuring no-load rotational breakaway torque of self-lubric
6、ating spherical bearings.2. REFERENCES2.1 Applicable DocumentsThe following publications form a part of this document to the extent specified herein. The latest issue of SAE publications shall apply. The applicable issue of other publications shall be the issue in effect on the date of the purchase
7、order. In the event of conflict between the text of this document and references cited herein, the text of this document takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained.2.1.1 ANSI Accredited PublicationsCop
8、ies of these documents are available online at http:/webstore.ansi.org/ANS/ISO/IEC 17025 2005Calibration Laboratories and Measuring and Test Equipment - General Requirements Part 1ANSI/NCSL Z540.3 2007 Calibration Laboratories and Measuring and Test Equipment - General Requirements Part 22.2 Definit
9、ionsNO-LOAD ROTATIONAL BREAKAWAY TORQUE: No-load rotational breakaway torque of a spherical bearing is the torque required to initiate rotation of the ball with respect to the race with no radial or axial loads applied.3. GENERAL REQUIREMENTS3.1 Test Apparatus3.1.1 The test fixture shall provide a m
10、eans of holding the outer ring of the bearing fixed while rotating the ball about the bearing axis.SAE INTERNATIONAL ARP5448/5A Page 2 of 23.1.2 The test fixture shall provide a means of holding the outer ring in such a manner as to minimize bearing distortion and the resultant effect on bearing tor
11、que.3.1.3 The test fixture shall provide a means of rotating the ball without excessive clamping forces or otherwise distorting the ball so as to affect the bearing torque.3.1.4 The test fixture shall provide a means of measuring the rotational torque at which ball rotation is initiated. The accurac
12、y of the torque measuring device shall be 5% of the indicated value.3.1.5 Calibration of the test apparatus shall be in accordance with ANSI-NCSL Z540-1.3.2 TemperatureUnless otherwise specified, temperature of the test area shall be 75 F 10 F.3.3 Relative HumidityRelative humidity of the test area
13、shall not exceed 75%.4. DETAILED REQUIREMENTS4.1 Stabilize the test bearing at the temperature and relative humidity of the test area.4.2 Place the test bearing in the test fixture and apply the holding feature to the outer ring.4.3 Unless otherwise specified, misalign the ball in two mutually perpe
14、ndicular planes and rotate through two to three revolutions immediately prior to testing. This may be accomplished by hand or with the assistance of an appropriately sized test shaft inserted in the bore of the bearing.4.4 Gradually apply torque to the ball until rotation begins.4.5 Record the torqu
15、e at which ball rotation is initiated.5. NOTES5.1 Intended UseThis test method provides procedures for measuring no-load rotational breakaway torque of standard airframe self-lubricating spherical bearings and similar non-standard bearings.5.2 Method of ReferenceThis test method may be referenced in
16、 general and detail specifications, standards or drawings for self-lubricating spherical bearings. Specific data requirements are given in the applicable document. The following note is suggested to reference this test method:“NOTE: Measure no-load rotational breakaway torque in accordance with ARP5
17、448/5.”5.3 Revision IndicatorA change bar (I) located in the left margin is for the convenience of the user in locating areas where technical revisions, not editorial changes, have been made to the previous issue of this document. An (R) symbol to the left of the document title indicates a complete revision of the document, including technical revisions. Change bars and (R) are not used in original publications, nor in documents that contain editorial changes only.PREPARED BY SAE COMMITTEE ACBG, AIRFRAME CONTROL BEARINGS GROUP
