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 andsuggestions.Copyright 2016 SAE InternationalAll rights reserved. No part of this public
3、ation 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 (outs
4、ide USA)Fax: 724-776-0790Email: CustomerServicesae.orgSAE WEB ADDRESS: http:/www.sae.orgSAE values your input. To provide feedbackon this Technical Report, please visithttp:/www.sae.org/technical/standards/ARP5448/3AAEROSPACERECOMMENDED PRACTICEARP5448/3 REV. AIssued 2002-07Reaffirmed 2010-06Revised
5、 2016-07Superseding ARP5448/3Plain Bearing Low Speed Oscillation TestRATIONALEThis revision clarifies and expands sections 3.1.1.3, 3.1.1.4, 3.2, 4.2, 4.3, and 5.3.2 in order to better characterize the high and low temperature test setup and procedure. There are also editorial corrections in 4.4 and
6、 5.3.4.j. 1. SCOPE1.1 PurposeThis test method outlines a recommended procedure for performing unidirectional load dynamic testing of self-lubricating bearings at room temperature, elevated temperature or sub-zero temperature, dry or contaminated with fluids. The wear data from these tests is to be u
7、sed for qualification and to establish bearing design criteria.1.2 ClassificationBearings covered by this test method shall be plain spherical bearings, which are self-aligning or plain sleeve bearings.2. REFERENCES2.1 Applicable DocumentsThe following publications form a part of this document to th
8、e 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 order. In theevent of conflict between the text of this document and references cited herein, the text of this document tak
9、es precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained.2.1.1 ASTM PublicationsAvailable from American Society for Quality, 600 North Plankinton Avenue, Milwaukee, WI 53203, Tel: 800-248-1946 (United States or Canada)
10、, 001-800-514-1564 (Mexico), or +1-414-272-8575 (all other locations), www.asq.org.ASTM E4 Standard Methods of Verification of Testing MachinesASTM E83 Standard Practice for Verification and Classification of Extensometer SystemsSAE INTERNATIONAL ARP5448/3A Page 2 of 82.1.2 ANSI PublicationsCopies o
11、f these documents are available online at http:/webstore.ansi.org.ANSI/NCSL Z540.3 Requirements for the Calibration of Measuring and Test Equipment2.1.3 ISO PublicationsAvailable from International Organization for Standardization, ISO Central Secretariat, 1, ch. de la Voie-Creuse, CP 56, CH-1211 Ge
12、neva 20, Switzerland, Tel: +41 22 749 01 11, www.iso.org.ISO 10012 Measurement Management Systems Requirements for Measurement Processes and Measuring Equipment2.2 DEFINITIONSNot applicable.3. GENERAL REQUIREMENTS3.1 Test Apparatus3.1.1 Test MachineThe test machine shall be capable of applying a uni
13、directional load of controlled magnitude to the bearing race while the ball (for spherical bearings) or shaft (for sleeve bearings) is oscillated through a prescribed angle. Loads shall be capableof being maintained within +3/-0% of the test requirement. Angle of oscillation shall be capable of bein
14、g maintained within 0.5 degrees of the test requirement. The bearing shall be mounted to place the shaft in double shear with a minimum of bending. The machine shall include the following accessory equipment for complete testing capability.3.1.1.1 Bearing HoldersAppropriate size bearing holders shal
15、l be made of steel. Provisions to bush these holders are recommended.3.1.1.2 Test ShaftsAppropriate size test shafts shall be made of steel with a hardness of Rc 45 minimum or CRES, 13-8, condition H-950, and may be chrome plated or nickel plated. When testing sleeve bearings, it is acceptable for s
16、ome test machine setups to require bushings to act as an inner race. All further statements about shafts shall also apply to shaft/bushing combinations.Cres is recommended for shafts because of its increased fatigue properties. Shafts for testing sleeve bearings shall have 8 Ra max. surface finish o
17、n the outside diameter and be polished after grinding.3.1.1.3 Temperature Heating System for Elevated Temperature TestA temperature heating system shall permit heating the test bearing to a controlled temperature and maintaining it there for the duration of a test. One approach to accomplish this is
18、 to construct an insulated enclosure that completely surrounds the bearing under test and introducing heated air (from resistance heaters) as a heating medium. As most airframe bearing standards with an elevated temperature test have requirements for controlled temperature (at the ball liner interfa
19、ce for spherical bearings or shaft liner interface for sleeve bearings), the monitor/controller thermocouple shall be located as close as possible to these areas. Locate the thermocouples within 45 degrees of the center of the load zone. Temperature monitors/controllers shall be accurate within 5 F.
20、SAE INTERNATIONAL ARP5448/3A Page 3 of 83.1.1.4 Temperature Cooling System for Sub-Zero Temperature TestA temperature cooling system shall permit cooling the test bearing to a controlled temperature and maintaining it there for the duration of a test. One approach to accomplish this is to construct
21、an insulated enclosure that completely surrounds the bearing under test and introducing N2 or CO2 as a cooling medium. As most airframe bearing standards with a sub-zero temperature test have requirements for controlled temperature (at the ball liner interface for spherical bearings or shaft liner i
22、nterface for sleeve bearings), the monitor/controller thermocouple shall be located as close as possible to these areas. Locate the thermocouples within 45 F of the center of the load zone. Temperature monitors/controllers shall be accurate within 5 F.3.1.1.5 Radial Displacement IndicatorA dial indi
23、cator or electronic pickup device, accurate within 0.0002 inch, shall be mounted to permit measurement of any radial movement of the race with respect to the ball for spherical bearings or radial movement of the journal with respect to the shaft for sleeve bearings. The preferred system is to measur
24、e bearing holder displacement with respect to the test shaft.The next preferred method is to measure bearing holder displacement with respect to some fixed surface. The least preferred method is measurement at some remote site.3.1.1.6 Liquid Contaminator SystemA liquid contaminator system shall intr
25、oduce liquid contaminants to each side of the test bearing during dynamic testing.This system shall have provisions to accurately regulate the flow rate of the contaminant. Provisions shall also be made to catch the fluids.3.1.1.7 Cycle CounterProvisions shall be made to count cycles.3.1.1.8 Load Mo
26、nitorProvisions shall be made to monitor load.3.1.1.9 Torque MonitorProvisions shall be made to monitor torque to rotate the test spindle for reference purposes. It is advisable for the test laboratory to have previously determined the torque attributable to the support bearings of the test rig spin
27、dle in order to isolate torque due to the test bearings.3.1.2 CalibrationCalibration of the instrumentation shall be in accordance with manufacturers specifications and shall be within limits at thetime of the test.3.1.3 Equipment VariationsVariations to the test equipment and associated methods req
28、uired herein are permissible provided the procuring activity is provided with sufficient calibration data to verify the accuracy of the test conditions/results.3.2 Test SpecimenSpherical bearings shall be prepared for testing by notching or otherwise permanently marking the outer race to identify th
29、e center of load zone. Sleeve bearings shall have the center of the load zone identified on the metallic sleeve.SAE INTERNATIONAL ARP5448/3A Page 4 of 84. DETAILED REQUIREMENTS4.1 ProcedureThe test bearing shall be installed in an appropriate bearing holder with a mark identifying the center of the
30、load zone.Fit between bearing O.D. and holder shall be 0.0000 to 0.0010 clearance fit for spherical and 0.0000 to 0.0010 interference fit for sleeve bearings. Fit between bearing I.D. and shaft for both spherical and sleeve shall be 0.0000 to 0.0010 clearance fit.The bearing holder, bearing and shaf
31、t shall be installed in the bearing test machine and mounted to place the shaft in doubleshear with a minimum of bending. Bearing support and adapter bushings or bushing face of sleeve bearings should be tight against the ball face of spherical bearings, but for spherical bearings, clamp-up on the b
32、all need not be controlled provided the ball is driven without slippage. Dial indicator or electronic pickup device shall be installed.The specified oscillating load shall be applied and held statically for 15 minutes minimum. At the end of this time the dial indicator or electronic pickup device sh
33、all be “zeroed.“The test shall be run in such a manner, that the ball for spherical bearings, or shaft and/or bushing of sleeve bearings, is oscillated X degrees minimum from the zero position. X degrees shall be stated in the test plan. A cycle shall consist of oscillation from zero to +X degrees a
34、nd return to zero to -X degrees and return to zero. Rate of oscillation for ambient temperature tests shall be specified in the test plan where the value of X is defined in the appropriate procurement specification.The oscillation test shall be started. Readings of wear, temperature (for elevated an
35、d sub-zero tests) and cycle count shall be recorded at the beginning of the test and at sufficient intervals to plot a graph of wear (ten-thousandths of an inch) versus life (cycles). Upon completion of the test, the loaded breakaway torque shall also be measured if specified in the test plan.4.2 El
36、evated Temperature TestsTesting at elevated temperature shall be as specified in 4.1. Any method of heating to maintain the ball (or bushing)/liner interface at the required temperature is acceptable. One example would be that the bearing be heated during the test by introducing heated air into an i
37、nsulated box surrounding the test station. Spherical and sleeve bearings (and bushing, if required) shall have a thermocouple attached as described in Section 3.The bearing holder, bearing and shaft (and bushing for sleeve bearings) shall be installed in the bearing test machine and mounted to place
38、 the shaft in double shear with a minimum of bending. Thermocouple leads should be located within 45 degrees to the center of the load zone. Bearing support and adapter bushings shall be tight against the ball face of spherical bearings or bushings face of sleeve bearings, but clamp-up need not be c
39、ontrolled providing the ball is driven without slippage.The temperature controller(s) shall be set at an adjusted temperature determined by calibration tests to guarantee that the test temperature at the ball (or bushing)/liner interface will be maintained as close as practical to the specified test
40、 temperature without exceeding it. After the controller(s) are set, allow a minimum 30 minutes for the temperature to stabilize.Rate of oscillation for elevated temperature tests shall be specified in the test plan.4.3 Sub-Zero Temperature TestsTesting at sub-zero temperature shall be as specified i
41、n 4.1 except that the bearing shall be cooled during the test by introducing N2 or CO2 gas into an insulated box surrounding the test station. Spherical and sleeve bearings (and bushing, if required) shall have a thermocouple attached as described in Section 3.The oscillation rate is optional except
42、 that the minimum shall be 5 CPM. Intermittent operation of the test machine is allowable if necessary to counteract the effects of frictional heating.SAE INTERNATIONAL ARP5448/3A Page 5 of 8After temperature controllers are set, the bearing shall be allowed to cold soak at the temperature for a min
43、imum of 30 minutes after which time oscillation may start.4.4 Fluid Compatibility, Immersion MethodTest bearings shall be wiped with isopropyl alcohol to remove any fingerprints or oil film and immersed for 24 hours in the test fluid at 160 F 5 F, exception: some fluids may chemically decompose, eva
44、porate, or simply not be intended for 160 F applications, therefore lower the soak temperature to their recommended maximum safe use.Within 30 minutes after removal from the test fluid, the bearing shall be tested as specified in 4.1.4.5 Fluid Compatibility, Drip Test MethodTests with liquid contami
45、nants present shall be conducted at ambient temperature as specified in 4.1. Prior to the test, the bearings shall be wiped with isopropyl alcohol to remove any fingerprints or oil film. Flow shall be controlled as close as practical to introduce liquid contaminants at a rate to equal or exceed one
46、drop per minute to each side of the test bearing.5. NOTES5.1 Intended UseThis test method is intended to provide a method to evaluate the performance of spherical or sleeve sliding self-lubricating bearings subject to unidirectional loads at room temperature, elevated temperature or sub-zero tempera
47、ture and dry or fluid contamination conditions.5.2 Method of ReferenceThis test method shall be referenced in general and detailed specifications, standards or drawings for sliding bearings.Specific test and data requirements are given in the Appendix or referencing document. The following note shal
48、l be used to reference this test method:NOTE: The bearings shall be tested in accordance with ARP5448/3. The slash number refers to this specific test method.5.3 Test Data5.3.1 Test ParametersSpecific test requirements are given in the referencing document. Test requirements shall include the follow
49、ing test parameters as applicable:a. Test specimen design envelopeb. Shaft and housing configurationc. Loadsd. Oscillation and/or misalignment anglese. Frequency of oscillationf. Temperature requirementsg. Cooling and/or heating requirementsh. Fluid contaminationSAE INTERNATIONAL ARP5448/3A Page 6 of 8i. Test durationj. Failure criteria (wear, loads, fluid contamination, etc.)5.3.2 Data RequirementsSpecific measurements
