1、SURFACE VEHICLERECOMMENDED PRACTICEJ2902 OCT2014Issued 2014-10Air Disc Brake Actuator Test Procedure, Truck-Tractor, Bus and TrailerRATIONALEThis new document has been created to separate the testing for air disc brake actuators from the s-cam drum brake actuator testing outlined in SAE J1469. The a
2、ir disc brake actuators are similar and do require most of the same testing as the s-cam drum brake actuators but do require some different tests. It is anticipated that development of new testing could take a different direction in some cases.1. SCOPEThis SAE recommended practice provides procedure
3、s and methods for testing service, spring applied parking and combination brake actuators for air disc brake applications. Methods and recommended samples for testing durability, function and environmental performance are listed in 1.1 and 1.2.1.1 Test ProceduresLeak rate-parking and service chamber
4、s (Section 4)Maximum release and hold-off pressure - parking chamber (Section 5)Minimum Pressure Response - Service Chambers (Section 6)Force output and stroke - parking and service chambers (Section 7)Low temperature leakage (Arctic option included) - parking and service chambers (Section 8)Low tem
5、perature maximum release and hold-off pressure (Section 9)Low temperature force output - parking chamber (Section 10)Low temperature operational tests - service chamber (Section 11)Chamber volume - service chambers (Section 12)Corrosion resistance - parking and service chamber (Section 13)Mechanical
6、 back-off release mechanism (Section 14)Elevated temperature cycle test - parking and service chambers (Section 15)Cycle test - parking and service chambers (Section 16)Proof pressure test-parking and service chambers (Section 17)Vibration test (Section 18)1.2 Test Sequence ChartThe test sequence, a
7、s charted in the “Test Sequence Chart”, shall be mandatory except where indicated as optional (see Figure 1).1.3 PurposeThis document provides uniform procedures and methods for laboratory testing of brake actuators used in heavy duty vehicles equipped with air disc brakes._SAE Technical Standards B
8、oard 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 therefrom, is the sole responsib
9、ility 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 2014 SAE InternationalAll rights reserved. No part of this publication may be reproduced,
10、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 (outside USA)Fax: 724-776-0790
11、Email: CustomerServicesae.orgSAE WEB ADDRESS: http:/www.sae.orgSAE values your input. To provide feedbackon this Technical Report, please visithttp:/www.sae.org/technical/standards/J2902_201410SAE INTERNATIONAL J2902 Issued OCT2014 Page 2 of 23FIGURE 1 - TEST SEQUENCE CHART2. REFERENCES2.1 Applicabl
12、e PublicationThe following publication forms a part of this specification to the extent specified herein. Unless otherwise indicated, the latest issue of SAE publications shall apply.2.1.1 ASTM PublicationAvailable from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA
13、19428-2959, Tel: 610-832-9585, www.astm.orgASTM B 117 Method of Salt Spray (Fog) TestingABCDEF ABCDEF ABCDEFPark 4.1 XXXXXX XXXXXXService 4.2 XXXXXX XXXXXXBot 4.3 XXXXXX XXXXXX5XX6X XPark 7.1 XXXXXX XXXXXXService 7.2 XXXXXX XXXXXXPark 8.1 X XService 8.2 X X9OOLow Temp Force Output Park 10 O O11 X XC
14、hamber Volume Service 12 X X13 X X X14 XX XXPark 15.1 X XService 15.2 X XPark 16.1 X X X X X XService 16.2 X X X X X XPark 17.1 X XService 17.2 X X18 O X XTEST UNIT DESIGNATIONTESTS FOR COMBINATIONSTEST UNIT DESIGNATIONLow Temp Max Release and Hold-OffLow Temp LeakageTEST PROCEDURE SECTION NO.Min. P
15、ressure ResponseTEST DESCRIPTIONMax Relaese and Hold-Off Leakage RateTESTS FOR SERVICE CHAMBERS ONLYTEST UNIT DESIGNATIONTESTS FOR PARK CHAMBERS ONLYItems marked with “O“ are optional, to be performed only as required by the vehicle manufacturer or customer.VibrationForce Output and StrokeCycle Test
16、Low Temp OperationalCorrosion Mechanical Back-Off ReleaseElevated Temp TestProof PressureSAE INTERNATIONAL J2902 Issued OCT2014 Page 3 of 233. DEFINITIONS3.1 HOLD-OFF PRESSUREA decrease of parking chamber air pressure for parking brake application (extend power spring).3.2 RELEASE PRESSUREAn increas
17、e of parking chamber air pressure to release the parking brake (compress power spring).3.3 PARKING CHAMBER APPLYExtend power spring.3.4 PARKING CHAMBER RELEASECompress power spring.3.5 FULL STROKEMaximum stroke of a unit.3.6 RATED STROKEMinimum design stroke of a unit.3.7 SERVICE BRAKE ACTUATORAir a
18、ctivated actuator for applying the foundation brake.3.8 PARKING BRAKE ACTUATORMechanically applied actuator for applying the foundation brake.3.9 COMBINATION BRAKE ACTUATORCombined service and parking section actuator.3.10 ZERO STROKEBrake actuator push rod must be in fully retracted position.3.11 F
19、ULLY CAGED POWER SPRINGPower spring retracted in its most compressed position within the brake actuator.NOTE: This may be accomplished either pneumatically or mechanically per the manufacturers recommended procedure.SAE INTERNATIONAL J2902 Issued OCT2014 Page 4 of 234. LEAK RATE - PARKING AND SERVIC
20、E CHAMBERS4.1 Leakage - Parking Chamber4.1.1 Conditions4.1.1.1 27 11 qC (80 20 qF) ambient temperature.4.1.1.2 Limit the stroke to 75% 5% of rated stroke.4.1.1.3 Parking chamber is to be uncaged.4.1.2 Test Procedure4.1.2.1 Preconditioning Cyclea. Pneumatically actuate the parking chamber from fully
21、applied to fully released and back to fully applied three times using 620 kPa to 830 kPa (90 lbf/in2to 120 lbf/in2) (gage) air pressure.4.1.2.2 Pressurize the parking chamber with air 860 to 896 kPa (125 lbf/in2to 130 lbf/in2) (gage).4.1.2.3 Stabilize the air pressure for a minimum of 5 minutes.4.1.
22、2.4 Establish air pressure at 896 kPa 7 kPa (130 lbf/in2 1 lbf/in2) (gage).4.1.2.5 Measure leakage rate with a flow meter.4.1.2.6 Record leakage rate.4.1.3 Alternate Test Procedure4.1.3.1 Preconditioning cycles per 4.1.2.1.4.1.3.2 Connect the parking chamber to a 20 485 cm3 820 cm3(1250 in3 50 in3)
23、air tank. U.S. 5 Gallon tank is an acceptable alternative.4.1.3.3 Connect a pressure gage (or equivalent device) to measure pressure change.4.1.3.4 Pressurize the parking chamber and air tank 860 kPa to 896 kPa (125 lbf/in2to 130 lbf/in2) (gage) air pressure.4.1.3.5 Stabilize the air pressure in the
24、 parking chamber and tank for a minimum of 5 minutes.4.1.3.6 Establish a pressure of 896 kPa 7 kPa (130 lbf/in2 1 lbf/in2) (gage) in the parking chamber and air tank andclose shut-off valve at the air tank inlet.4.1.3.7 Record the pressure change after 10 min 0.1 min.4.2 Leakage - Service Chamber4.2
25、.1 Conditions4.2.1.1 27 11 qC(80 20 qF) ambient temperature.4.2.1.2 Limit the stroke to 75% 5% of rated stroke.4.2.1.3 Maintain the parking chamber at 860 kPa to 896 kPa (125 lbf/in2to 130 lbf/in2) (gage) - if applicable.SAE INTERNATIONAL J2902 Issued OCT2014 Page 5 of 234.2.2 Test Procedure4.2.2.1
26、Precondition Cyclesa. Cycle the service chamber three times pneumatically by applying 620 to 830 kPa (90 lbf/in2to 120 lbf/in2) (gage) from zero stroke to 75% 5% stroke and back to zero stroke position.4.2.2.2 Pressurize the service chamber with 860 kPa to 896 kPa (125 lbf/in2to 130 lbf/in2) (gage)
27、air pressure.4.2.2.3 Stabilize the air pressure for a minimum of 5 min.4.2.2.4 Establish a pressure of 896 kPa 7 kPa (130 lbf/in2 1 lbf/in2) (gage) in the service chamber.4.2.2.5 Measure leakage rate with a flow meter.4.2.2.6 Record leakage rate.4.2.3 Alternate Test Procedure4.2.3.1 Preconditioning
28、cycles per 4.2.2.1.4.2.3.2 Connect the service chamber to a 20 485 cm3 820 cm3(1250 in3 50 in3) air tank. U.S. 5 Gallon tank is an acceptable alternative.4.2.3.3 Connect a pressure gage (or equivalent device) to measure pressure change.4.2.3.4 Pressurize the service chamber and air tank 860 kPa to 8
29、96 kPa (125 lbf/in2to 130 lbf/in2) (gage).4.2.3.5 Stabilize the air pressure in the service chamber and tank for a minimum of 5 minutes.4.2.3.6 Establish a pressure of 896 kPa 7 kPa (130 lbf/in2 1 lbf/in2) (gage) in the service chamber and air tank then close shut-off valve at the air tank inlet.4.2
30、.3.7 Record the pressure change after 10 min 0.1 min.4.3 Leakage - Disc Brake Caliper Flange Seal / Pushrod Boot Seal4.3.1 Conditions4.3.1.1 27q C 11q C (80q F 20q F) ambient temperature4.3.1.2 Maintain the parking chamber at 860 kPa to 896 kPa(125 lbf/in2to 130 lbf/in2) (gage)if applicable. 4.3.1.3
31、 Caliper flange test fixture should simulate the actual air disc brake caliper with regard to sealing flange of theinternal rubber boot, surface conditions, finish and rigidity. See Figure 2. Calipers to be used with the actuator should be considered.SAE INTERNATIONAL J2902 Issued OCT2014 Page 6 of
32、23FIGURE 2 - DISC BRAKE CALIPER FLANGE LEAKAGE TEST SCHEMATIC4.3.2 Test Procedure4.3.2.1 Apply 21.0 kPa 3.0 kPa (3.0 lbf/in2 0.5 lbf/in2) (gage) air pressure to the caliper flange test fixture. Allow to stabilize for a minimum of five (5) minutes, then close air valve. 4.3.2.2 Record the pressure ch
33、ange after 10 min 0.1 min. 4.3.2.3 Apply vacuum of -21.0 kPa 3.0 kPa (-3.0 lbf/in2 0.5 lbf/in2) (gage) air pressure to the caliper flange test fixture. Allow to stabilize for a minimum of five (5) minutes, then close air valve. 4.3.2.4 Record the pressure change after 10 min 0.1 min. 5. MAXIMUM RELE
34、ASE AND HOLD-OFF PRESSURE - PARKING CHAMBER5.1 Conditions5.1.1 27 qC 11 qC (80 qF 20 qF) ambient temperature. 5.2 Test Procedure5.2.1 Power Spring Preset - Parking Brake5.2.1.1 Fully cage the power spring in the parking chamber either pneumatically or mechanically as specified by the manufacturer.5.
35、2.1.2 Maintain the power spring in the caged position for 24 h minimum.SAE INTERNATIONAL J2902 Issued OCT2014 Page 7 of 235.2.1.3 Release the power spring to a full stroke position after the required preset period.5.2.1.4 Apply preconditioning cycles per 4.1.2.1. 5.2.1.5 On the third cycle, measure
36、and record stroke versus air pressure in the apply and release direction for the full stroke of the brake actuator. It is recommended measurements be taken in 5.0 mm (0.20 in) increments or as otherwise specified.6. MINIMUM PRESSURE RESPONSE - SERVICE CHAMBERS6.1 Conditions6.1.1 27 11 qC (80 20 qF)
37、ambient temperature6.1.2 Maintain the parking chamber at 860 kPa to 896 kpa (125 lbf/in2to 130 lbf/in2) (gage) - if applicable. 6.2 Test Procedure6.2.1 Slowly apply air pressure to the Service Chamber port. Measure and record air pressure value at which the pushrod extends to 5 0.5 mm (0.20 0.02 in)
38、. This is the Service Chamber Response Pressure. See test apparatus as shown in Figure 3.6.3 Alternate Test Procedure6.3.1 Record plot of chamber pressure vs. stroke from fully released to fully applied position. See test apparatus as shown in Figure 3. Pressurize chamber slowly such that the test t
39、ime is 30 seconds, push rod travel speed should be approximately 152 mm (6”) per minute. Service Chamber Response Pressure shall be the pressure recorded at 5 mm (0.20 in.) stroke.FIGURE 3 - MINIMUM PRESSURE RESPONSE TEST SCHEMATICSAE INTERNATIONAL J2902 Issued OCT2014 Page 8 of 237. FORCE OUTPUT AN
40、D STROKE - PARKING AND SERVICE CHAMBERS7.1 Force Output - Parking Chamber7.1.1 Conditions7.1.1.1 27 11qC(8020qF) ambient temperature. 7.1.2 Test Procedure7.1.2.1 Mount the test actuator to a holding fixture using mounting hardware specified by the manufacturer and tightened to the manufacturers reco
41、mmended torque. The holding fixture shall be constructed with sufficient strength and rigidity to minimize fixture deflection under loading (Figure 4). The fixture shall be made to simulate the caliper flange seal boot cavity and contact area profile or a shim may be used for this purpose as shown i
42、n Figure 4 (ref. also Figure 6, same shim may be used).7.1.2.2 Apply preconditioning cycles per 4.1.2.1.7.1.2.3 Install the test unit and holding fixture in a suitable force versus stroke measuring equipment.NOTE: Test fixturing must provide guiding of the test units pushrod which will assure a push
43、rod angularity with the mounting surface of the chamber of 90 degrees 1 degree during force output testing (ref. Flat End Rod Adapter Figure 4).7.1.2.4 Apply 690 kPa to 830 kPa (100 lbf/in2to 120 lbf/in2) (gage) air pressure to the parking chamber to fully compress the power spring (if applicable).7
44、.1.2.5 If an X-Y recorder is used to measure force versus stroke, “zero” the force output on the X-Y recorder at this point in the procedure.7.1.2.6 Apply a 35 N to 45 N (8 lbf to 10 lbf) preload to the end of the test units pushrod.7.1.2.7 If an X-Y recorder is used, “zero” the linear displacement
45、(pushrod travel) on the X-Y recorder after the 35 N to 45 N (8 lbf to 10 lbf) preload has been applied.7.1.2.8 Gradually release all air pressure from the parking chamber and record the parking chamber force versus stroke from zero to full stroke in the brake application direction (stroke extend) in
46、 0 mm to 5.0 mm (0 in to 0.20 in) increments. If an X-Y recorder is used, plot a force versus stroke curve. Force outputs shall be measured at the end of the service chamber pushrod when activated by the parking chamber from zero to full stroke.SAE INTERNATIONAL J2902 Issued OCT2014 Page 9 of 23FIGU
47、RE 4 - FORCE OUTPUT TEST SCHEMATICSAE INTERNATIONAL J2902 Issued OCT2014 Page 10 of 237.2 Force Output And Stroke - Service Chamber7.2.1 Conditions7.2.1.1 27 11 qC (80 20 qF) ambient temperature. 7.2.2 Test Procedure7.2.2.1 Mount Unit to Test Fixture - Same as procedure specified in 7.1.2.7.2.2.2 Cy
48、cle the service chamber three times pneumatically from full stroke to zero stroke and back to full stroke using 620 kPa to 830 kPa (90 lbf/in2to 120 lbf/in2) (gage).7.2.2.3 Install the test unit and holding fixture in suitable force versus stroke measuring equipment.NOTE: Test fixturing must provide
49、 guiding of the test unit pushrod which will assure a pushrod angularity with the mounting surface of the chamber of 90 degrees 1 degree during force output testing.7.2.2.4 Fully cage the power spring in the parking chamber (if applicable) pneumatically . If an X-Y recorder is used to record force versus stroke, “zero” the force output on the X-Y record
