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 there
2、from, 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 2013 SAE International All rights reserved. No part of this p
3、ublication 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: +1 724-776-497
4、0 (outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org SAE values your input. To provide feedback on this Technical Report, please visit http:/www.sae.org/technical/standards/J2488_201303 SURFACE VEHICLE RECOMMENDED PRACTICE J2488 MAR2013 Issued 2000-04 Re
5、vised 2013-03 Superseding J2488 AUG2006 SAE No.2 Friction Test Machine 6000 r/min Stepped Power Test RATIONALE It has been found that the current described pressure plate design can influence the results by creating a hydraulic cushion during operation. Installation of oil relief holes eliminates th
6、is possibility. Oil relief holes have become the defacto standard for many test labs running friction plate or transmission fluid testing. The current release level of the specification had several instances of possibly confusing formatting. One change was necessary in view of safety related changes
7、 to the inertia confinement vaults. 1. SCOPE This SAE Recommended Practice is intended as the definition of a standard test, but may be subject to frequent change to keep pace with experience and technical advances. This should be kept in mind when considering its use. The SAE No. 2 Friction Test Ma
8、chine is used to evaluate the friction characteristics of automatic transmission plate clutches with automotive transmission fluids. It can also be used to conduct durability tests on wet friction systems. The specific purpose of this document is to define a 6000 r/min Stepped Power Test for the eva
9、luation of wet friction system performance variation as a function of power level. This procedure uses an initial engagement speed of 6000 r/min and is intended as a standard procedure for common use by both suppliers and end users. The only variables selected by the supplier or user of the friction
10、 system are: a. Friction Material b. Fluid c. Reaction Plates These three variables must be clearly identified when reporting the results of using this test. If any of the test parameters or system hardware as described in this document are changed, other than the friction material, test fluid, or r
11、eaction plates, the data may not be reported as having been obtained using this document. This procedure is not intended to evaluate the initial coefficient or break-in characteristics. For this information, refer to SAE J2490 SAE No. 2 Friction Test Machine g80PVT Test. SAE J2488 Revised MAR2013 Pa
12、ge 2 of 26 2. REFERENCES 2.1 Applicable Documents The following publications form a part of this specification to the extent specified herein. Unless otherwise indicated, the latest issue of SAE publications shall apply. 2.1.1 SAE Publications Available from SAE International, 400 Commonwealth Drive
13、, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or 724-776-4970 (outside USA), www.sae.org. SAE J286 SAE No. 2 Clutch Friction Test Machine Guidelines SAE J1646 Glossary of Terms - Lubricated Friction Systems SAE J2490 SAE No. 2 Friction Test Machine g80PVT Test 2.2 Related Pu
14、blications The following publications are provided for information purposes only and are not a required part of this SAE Technical Report. 2.2.1 SAE Publications Available from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or 724-776-
15、4970 (outside USA), www.sae.org. SAE J1499 SAE Band Friction Test Machine Guidelines SAE Paper 670051 New Fixture for Testing Friction Materials for Automatic Transmission Clutch SAE J2487 SAE No. 2 Friction Test Machine 3600 r/min Stepped Power Test SAE J2489 SAE No. 2 Friction Test Machine Durabil
16、ity Test SAE J2488 Revised MAR2013 Page 3 of 26 3. TEST EQUIPMENT 3.1 SAE No. 2 Friction Test Machine with breakaway accessory. 3.2 Flywheels to deliver desired kinetic energy. The flywheels required to provide the specified step changes in total system inertia are shown in Tables 1A and 1B. 3.3 Dat
17、a Acquisition At not less than 1000 samples per second and storage system with at Ieast four channels with response as follows: a. Torque Channel, Bandwidth - 500 Hz. b. Apply Pressure Channel, Bandwidth - 500 Hz. c. Speed Channel, Bandwidth - 500 Hz. d. Test Fluid Temperature Channel, Bandwidth - 3
18、 Hz. (All channels are to be calibrated to maintain 2% accuracy throughout the range of 10% of full scale to full scale). 3.4 Instrumentation a. Torque Transducer - Full bridge, strain gage type, with combined nonlinearity and hysteresis effects not to exceed 0.5% of full scale, such as Lebow Load C
19、ell, Model 3397. b. Apply Pressure Transducer - Full bridge, strain gage type, with combined nonlinearity and hysteresis effects not to exceed 0.5% of full scale, such as Sensotech, Model TJU708-12. c. Speed Transducer - Optical Encoder for drive motor, such as BEl Model 924-01002-4839. d. Thermocou
20、ple(s) - Type J with high-impedance amplifier and cold junction compensator. SAE J2488 Revised MAR2013 Page 4 of 26 TABLE 1A - REQUIRED INERTIA 6000 R/MIN INITIAL SPEED Step Level Total Inertia (kg-m2) Incremental Flywheel Interia (kg-m2) Possible Flywheels Energy (kJ) 1 0.142 Motor+A A 28.08 2 0.15
21、6 0.013 A+B 30.76 3 0.169 0.013 A+2B 33.43 4 0.183 0.013 A+C 36.11 5 0.197 0.013 A+B+C 38.78 6 0.210 0.013 A+2B+C 41.46 7 0.224 0.013 A+D 44.13 8 0.237 0.013 A+B+D 46.80 9 0.251 0.013 A+2B+D 49.48 10 0.264 0.013 A+C+D 52.15 11 0.278 0.013 A+B+C+D 54.83 12 0.292 0.013 A+2B+C+D 57.50 13 0.305 0.013 A+
22、2C+D 60.22 TABLE 1B - POSSIBLE FLYWHEELS REQUIRED FOR THE TEST Code Quantity Inertia (kg-m2) A 1 As required to achieve Level 1 inertia of 0.142 B 2 0.013 C 2 0.039 D 2 0.078 3.5 Test Fluid System (Figure 1C in SAE J286) Heated sump including immersion or jacket heater with sufficient watt density f
23、or test fluid temperature control and the associated hardware for external fluid flow control. Care should be taken that the fluid is not altered or modified by contact with the immersion heater by ensuring that the heater does not exceed a power density of 2 W/cm2. 3.6 Adapters and Reaction Plates
24、The required friction, reaction plates, hub, retainer and pressure plates and spacers are all described in Appendix A. 3.7 Apply Piston Seal a. VITONb. Teflon- Recommended for use in high temperature fluid tests. 3.8 Lubrication System Flow Configuration 3.8.1 External Flow (Figure 7C in SAE J1646).
25、 This represents the configuration wherein an external pump supplies fluid at a specific flow rate through a line to the centerline of the shaft. A flow meter must be installed in the line to the cover to measure the flow supplied to the head. The drain to the sump is located at the 5, 6, and 7 oclo
26、ck positions. SAE J2488 Revised MAR2013 Page 5 of 26 4. TYPICAL OPERATING CONDITIONS AND TEST PARAMETERS 4.1 Piston Area 15 110 mm2. 4.2 Piston Available Travel 4.57 mm. 4.3 Piston Apply Pressure As required to produce the required stop time of 0.6 s for each engagement. Allowable variation in stop
27、time is 0.5% or 3.0 ms (see Reference SAE J1646 for definitions). a. Start Threshold Torque b. Stop Threshold Torque 4.4 Piston Apply Pressure Rise The apply pressure must be stable at the required level within 50 ms. The maximum overshoot must not exceed 2% of the required pressure level. 4.5 Pisto
28、n Release Pressure 30 to 100 kPa and must be 0 kPa during the apply period. 4.6 Effective Inertia Range The inertia range is from the effective base Inertia, which is the minimum inertia for the test, to some maximum as determined in the test. A flywheel specific to an individual dynamometer may be
29、required to attain the Level 1 inertia of 0.142 kg-m2. See Tables 1A and 1B. 4.7 Initial Engagement Speed 6000 r/min +0/20 r/min. 4.8 Kinetic Energy As shown in Figure B3 and Appendix B. These kinetic energy values must be as required for the specific level. The allowable variation in kinetic energy
30、 is 5%. 4.9 Breakaway Speed 4.37 r/min. 4.10 Test Fluid a. Quantity - 18 L minimum, and must be replaced with new fluid at the beginning of the procedure. b. Temperature - 115 C 5 C. Measured in the inlet line as shown in Appendix A. c. Test Fluid Flow - The test fluid flow rate is 1.0 L/min 0.05 L/
31、min. d. Fluid Flow Configuration - The flow configuration is External Flow as described in SAE J1646 and 3.8.1. SAE J2488 Revised MAR2013 Page 6 of 26 4.11 Pack Clearance 1.143 mm 0.127 mm 4.12 Test Periods Refer to SAE J1646 for the definitions of the test periods. The total period for one dynamic
32、engagement cycle is 30 s 1 s. a. T1, Stabilization Period - 25 s 0.5 s b. T2, Coast Period - 0 s c. T3, Apply Period - 2 s 0.1 s d. T4, Dwell Period - 3 s 0. s e. T5, Soak Period - 2.5 s 2.5 s f. T6, Breakaway Period - 2 s 0.5 s g. T7, Cooling period - 0 4.13 Test Description The procedure, as descr
33、ibed in detail in Appendix B, consists of increasing steps of power, each level consisting of 200 engagements and one breakaway. Inspections are made of the reaction plates and friction assemblies at the end of each level. The different power levels are achieved by increasing the effective inertia w
34、hile the stop time and initial engagement speed are kept constant at 0.6 s and 6000 r/min respectively. The test is run at increasing power steps until the friction system has completely failed. 5. GENERAL TEST INFORMATION 5.1 Clean Prior to each test, the fixture and sump must be cleaned thoroughly
35、 and fixture and sump washed with solvent. The sump is then filled with the new test fluid. 5.2 Inspect Inspect rotating shaft seal for deterioration and replace, if necessary. If this seal is replaced, also replace the nonrotating lip seals. 5.3 Soak Soak friction elements in the test fluid for at
36、least 10 min at room temperature, 5.4 Measure and Record Measure and record the thickness of each friction element, after 5.3 before test and again after each test level at the same predetermined locations. A minimum of three locations, 120 degrees apart, at the approximate mean radius are to be ide
37、ntified by a durable mark and used for all measurements. The measurements from the various locations for each element are averaged and also averaged for the elements. These average changes in thickness from the original thickness are reported as the average cumulative loss of thickness. Measurements
38、 are made with a flat anvil meter with a 3.175 mm minimum diameter and 0.0127 mm accuracy. SAE J2488 Revised MAR2013 Page 7 of 26 5.5 Mark Surfaces Mark mating surfaces on the tab face of splines in sequence of assembly for orientation of the friction assemblies and reaction plates. The clutch pack
39、must be disassembled and reassembled with the exact same orientation of the component with respect to each other and to the stationary splines in the housing. All markings should be visible from the cover end of the housing. 5.6 Install Clutch Pack Install a reaction plate to contact the pressure pl
40、ate. Follow with a friction assembly, reaction plate, and so on until all the required components have been installed. The last plate to be installed must be a reaction plate. Its thickness (spacer) must be selected to ensure that the pack clearance is as defined in 4.11. The pack configuration is P
41、RFRFRFRSC, where P is the Piston, R is a Reaction plate, F is a Friction assembly, S the Spacer plate (as required), and C the Cover. Reaction plates may be used as the spacer. Verify axial alignment of Hub oil holes and friction plates (see Appendix A). 5.7 Install Flywheels Install the flywheels r
42、equired to achieve the effective inertia required for the power level to be evaluated. 5.8 Install Housing Cover Start the circulation pump and the temperature controller to heat the fluid and internal elements to the required control temperature, as given in 4.10. 5.9 Check Fluid Flow and Temperatu
43、re With the motor off, check that the fluid control temperature and the flow rate are as given in 4.10. 5.10 Start Test Determine pressure level to achieve the required 0.6 s stop time, as defined in 4.3. a. Always set the pressure to the low side of the estimated value as the test is to be aborted
44、if the stop time EVER falls below 0.55 s as uncontrolled friction system damage may occur. b. Initiate the testing for the required level as defined in Appendix B. c. The stop time MUST be set, per 4.3, by the 20th engagement and maintained during the remaining 180 engagements. 5.11 End of Level Ins
45、pection Shut down test stand. At the completion of the required dynamic engagements and the breakaway measurement, the housing is opened and the clutch pack carefully removed with special attention to ensure that the plates can be reinstalled in the exact same location and order relative to adjoinin
46、g plates and fixed locations in the housing. Measurements are made of the friction element thickness as noted in 5.4. Observations of the conditions of the reaction plates and friction elements and the fluid are recorded. Photographs may be taken to show the condition of the plates and assemblies. S
47、AE J2488 Revised MAR2013 Page 8 of 26 6. DATA ACQUISITION 6.1 Data Acquisition Rate For digital data acquisition systems the data is to be recorded at 1000 samples per second per channel using a 15 ms time constant RC filter. (Filtering will slew data. Preferred method is to record all raw data and
48、manipulate later.) 6.2 Coefficient Calculations Coefficients are calculated for the following dynamic coefficients at every 25th engagement. (Reference SAE J1646) a. Midpoint dynamic 50%g80db. Endpoint dynamic g100100msg80dmax(Based on raw data single point value) The breakaway coefficients, obtaine
49、d every 200 dynamic engagements, is defined as: Breakaway coefficient 1.0g80s4.376.3 Data Averaging and Filtering Data is to be averaged at the specified location in either the time or speed domain as specified in 6.1 with midpoint coefficient average values calculated using data points 80ms on both sides of the required calculation point. Endpoint coefficient average values are calculated from non-filt
