1、ARP5448/7Issued 2002-07Plain Bearing Wear Measurement1. SCOPE:This standard details two methods of inspecting TFE lined spherical or journal bearing wear outside the test apparatus. The methods described herein are applicable only to bearings which were unidirectionally loaded and the area of slidin
2、g wear is known and held constant throughout the dynamic test. The two methods described are:a. Destructive Inspection - Cut and measure (not applicable to molded liners)b. Non-destructive Inspection - Radial play (gage) measurement2. REFERENCES:There are no referenced publications specified herein.
3、3. DEFINITIONS:RADIAL PLAY: Refers to the total diametrical clearance in a bearing. The term radial refers to the direction of gage load and measurement axis. Radial play does not refer to taking only half the diametrical clearance nor measuring across the radius.4. REQUIREMENTS:NOTE: This method sh
4、all be useful only if the lined race of a spherical bearing or if the journal bearing were know to have remained stationary during the dynamic test. This method shall be useful only for unidirectional loading. Load reversal during a wear test will require alternate techniques.4.1 Destructive Inspect
5、ion:The scope of this test method shall be to measure the thickness of bearing liner remaining in the dynamic load zone with respect to unworn liner at a position 180 to the load zone. The required equipment shall be a metallurgical cut-off saw (preferred) or a hand hacksaw, micrometer calipers with
6、 ball anvil adapter, razor blade knife.Reaffirmed 2009-019AEROSPACE RECOMMENDED PRACTICE 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
7、and suitability for any particular use, including any patent infringement arising therefrom, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestio
8、ns. Copyright 2010 SAE International 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. TO PLACE A DO
9、CUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: 724-776-4970 (outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org SAE values your input. To provide feedbackon this Technical Report, please visit http:/www.sae.org/technical/standards/ARP5448/7C
10、opyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE ARP5448/7 - 2 -4.1.1 Test Specimen Preparation: Prior to measurement, misalign the ball and wipe clean to remove loose material. Repeat misalignment
11、 and wipe several times at different diameter locations. Compressed air may be used to flush out loose material, but care must be used to ensure that debris is not wedged into the bearing.4.1.2 Measurement Procedure:a. Cut race at a location approximately 10 to 15 with respect to the center of the l
12、oad zone. When using a metallurgical cut-off saw the cut shall proceed through the race and ball component as shown in Figure 1. If a hand hacksaw is to be employed, cut the race through the same 10 to 15 off load center and then at a location at 180 about the race to make two equal race halves.b. T
13、rim and scrape the liner material and adhesive from the race in the areas shown (TA and TB) in section A-A of Figure 1. When a spherical bearing race is being prepared, only the centerline of the race where the metal is the thinnest requires complete cleaning to the metal substrate. Be careful not t
14、o remove any metal when scraping away the bonded adhesive. Journal bearings should be completely stripped across the full width so that wear may be evaluated on both edges as bushing often wear unevenly due to tester misalignment.c. Take at least three measurements of the metal substrate thickness i
15、n equatorial area of a spherical and across the width of a journal bearing in the areas scraped clean of adhesive, determine minimum thickness and record measurements (Regions TA and TB).d. Take at least three measurements of the liner and metal backing thickness in the center of the loaded area of
16、a spherical race, or at each end and center of a bushing (wear zone) to determine minimum thickness and record measurements (Regions TO and TF).e. Repeat operation c approximately 180 from the loaded area of the race or bushing to determine minimum thickness of the metal substrate and record measure
17、ments. This region is considered the unloaded zone and the liner is considered unworn in this area.f. Repeat operation d approximately 180 to the loaded are of the race or bushing to determine minimum liner plus substratum thickness and record. This region is considered the unloaded zone and the lin
18、er is considered unworn in this area.g. Subtract the “race only“ measurement that is adjacent to the center of the unloaded area from the measurement of the liner and race thickness in the unloaded area of the race. Take at least three measurement readings. Use the minimum recorded value for each me
19、asurement. The difference is the thickness of the unworn section of liner material.h. Subtract the thickness of the worn section of liner from unworn section of liner, using the minimum recorded value of each measurement. The difference is the total wear of the liner system.Copyright SAE Internation
20、al Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE ARP5448/7 - 3 -FIGURE 1 - WorksheetCopyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license f
21、rom IHS-,-,-SAE ARP5448/7 - 4 -4.2 Non-destructive Inspection:The scope of this test method shall be to measure the radial play before and after a dynamic test to determine the increased radial play which shall be assumed to be liner wear. The required equipment shall be a radial play gage per ARP54
22、48/8 and a bore shaft or arbor if journal bearings are being tested.4.2.1 Measurement Procedure:a. Place the test bearing play gage per ARP5448/8. Ensure that the applied gage loads are in accordance with the applicable specification. The radial play of the new bearing shall be recorded. The locatio
23、n of the measurement should be marked on bearing permanently. The marked position shall be the load zone during dynamic testing. The initial radial play shall be used as a baseline to compare the play after dynamic testing. This method may be used to measure journal bearing wear by placing a pin wit
24、hin the bore of the bushing which is close to the bore size. The pin must be clamped and the bushing subjected to the reversing load of the play tester.b. Remove the test bearing from the radial play gage and perform dynamic testing as specified in the applicable specification.c. After dynamic testi
25、ng verify that the race or bushing has not rotated within its housing before demounting it from the test machine, misalign the ball of spherical bearings and wipe clean to remove loose wear debris. Repeat misalignment and wipe several times at different locations. Compressed dry air may be used to h
26、elp flush out loose debris , but care must be used to ensure material is not wedged into the bearing. The inner lined surface of journal bearings must simply be wiped of loose debris.d. Place the test specimen into the radial play gage as shown in Figure 2 so that the loaded area of the race and bal
27、l are in line with the radial play gage loading. Measure and record the radial play of the test specimen with the marked load zone in line with the reversing load of the play gauge.e. Determine the total wear of the liner system by subtracting the radial play before dynamic testing from the radial p
28、lay after dynamic testing.4.3 Test Parameters:Test parameters shall include the following:a. Test specimen design envelopeb. Dynamic test specificationc. Test durationd. Failure criteria (maximum radial clearance)Copyright SAE International Provided by IHS under license with SAENot for ResaleNo repr
29、oduction or networking permitted without license from IHS-,-,-SAE ARP5448/7 - 5 -FIGURE 2Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE ARP5448/7 - 6 -4.3.1 Data Requirements: Data requirements
30、shall include the following as applicable:a. Thickness of lined race at load zoneb. Thickness of metal race adjacent to load zonec. Thickness of lined race 180 from load zoned. Thickness of metal race only, load zone oppositee. Unworn liner thicknessf. Liner thickness at load zoneg. Destructive tota
31、l dynamic wearh. Gage loadi. Pre-dynamic test radial playj. Post-dynamic test radial playk. Non-destructive total dynamic wear 4.3.2 Test Report: The recorded data shall be summarized in report form and shall contain the following:a. Bearing description1. Manufacturer and manufacturer part number2.
32、Lot number3. A complete, dated drawing of the test bearing including dimensions and materialsb. Test machine descriptionc. Test parametersd. Raw data sheets for measurements and calculationsPREPARED UNDER THE JURISDICTION OFSAE SUBCOMMITTEE ACBG-1, PLAIN BEARING OFACBG, AIRFRAME CONTROL BEARINGS GROUPCopyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
