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 2011 SAE International All rights reserved. No part of this pub
3、lication 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
4、(outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.orgSAE values your input. To provide feedback on this Technical Report, please visit http:/www.sae.org/technical/standards/J1462_201110SURFACEVEHICLERECOMMENDEDPRACTICEJ1462 OCT2011 Issued 1985-06Revised 201
5、1-10Superseding J1462 MAY1994 External Automatic Brake Adjuster Test Procedure - Truck and Bus RATIONALEDeletion of obsolete terminology (i.e. “slack”), and inclusion of other clerical or error corrections and additional comments or clarification where appropriate. Verification and confirmation of r
6、esidual torque value in 6.3.2, 7.1.2, and 9.1.3, and totaldeflection rate value in 6.3.4, 7.1.4, and 9.1.5. 1. SCOPE This SAE Recommended Practice is intended for testing of external automatic brake adjusters as they are used in service, emergency, or parking brake systems for on-highway vehicle app
7、lications. 1.1 Purpose This document establishes an accelerated laboratory test procedure for external automatic brake adjusters to determine the integrity and durability in various functional modes and environmental conditions. 2. REFERENCES 2.1 Applicable Documents The following publications form
8、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, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or 724-776-
9、4970 (outside USA), www.sae.org.SAE J726 Air Cleaner Test Code SAE J786a Brake System Road Test Code - Truck, Bus, and Combination of Vehicles 2.1.2 ASTM Publication Available from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959, Tel: 610-832-9585, www.astm
10、.org.ASTM C 150-56 Specification for Portland Cement SAE J1462 Revised OCT2011 Page 2 of 25 2.1.3 FMVSS Publication Available from the Superintendent of Documents, U. S. Government Printing Office, Mail Stop: SSOP, Washington, DC 20402-9320.FMVSS-121 Air Brake SystemsTractors, Trucks, Buses and Trai
11、lers 3. Units to be tested per the schedule shown in Figure 1. 4. FUNCTIONAL TEST At ambient temperature of 27 C 11 C (80 F 20 F), the following functional tests should be performed. 4.1 Adjusting Torque Per the manufacturers recommendations, rotate the adjusting shaft until the worm wheel has made
12、one revolution in the brake applied direction and then in the brake released direction. Record the maximum torque in each direction. FIGURE 1 - SEQUENCE OF TESTS 4.2 Backlash Mount a brake adjuster in an appropriate rigid fixture so that no movement is allowed between the fixture and the worm wheel.
13、 Measure and record the free movement of the brake adjuster arm at a distance of 152.4 mm (6 in) from the center of the worm wheel by applying a torque of 6.78 Nm 0.34 Nm (60 in-lb 3 in-lb) in each direction. Rotate adjusting shaft such that the worm wheel rotates to a new position of 72 degrees 3 d
14、egrees from the previous position and make the backlash check. Repeat this procedure until five measurements have been made covering the worm wheel circumference. Measurements may be taken at any arm length; however, the data shall be factored in terms of 152.4 mm (6 in) arm lengths. SAE J1462 Revis
15、ed OCT2011 Page 3 of 25 5. EXTREME TEMPERATURE CONDITIONING 5.1 Submerge the brake adjuster in tap water and pressurize the container to 21 kPa 7 kPa (3 psi 1 psi) for 24 h minimum.5.2 Immediately, without drying, subject the brake adjuster and fixture to 40 C 1.1 C (40 F 2 F) for 16 h minimum, then
16、 cycle three times with 5.1 cm 0.64 cm (2.00 in 0.25 in) initial stroke while still at 40 C (40 F). Test set up per 6.3.1, 6.3.2, and 6.3.4 with 203 Nm (1800 lbf-in) applied torque. 5.3 Subject the brake adjuster and fixture to 70 C 2.8 C (158 F 5 F) for 16 h minimum, then cycle 100 times with 5.1 c
17、m 0.64 cm (2.00 in 0.25 in) initial stroke while still at 70 C (158 F). Test set up per 6.3.1, 6.3.2, and 6.3.4 with 203 Nm (1800 lbf-in) applied torque. 5.4 Return to ambient conditions and remove the brake adjuster from the test fixture. 6. CORROSION RESISTANCE 6.1 Environmental Chamber A salt-spr
18、ay cabinet may be constructed with the following specifications: a. Approximate size 457.2 mm x 457.2 mm x 304.8 mm (18 in x 18 in x 12 in) deep. b. The chamber preferably is constructed of metal and lined with impervious plastic, rubber, or epoxy material. c. All piping which contacts the salt solu
19、tion should be of inert material such as plastic. A vent pipe to be installed to minimize back pressure. d. An air chamber is to be mounted externally with the pushrod extending into the chamber, a suitable boot is to be used to minimize loss of solution. e. The brake adjuster is to be mounted on a
20、spline shaft which can be rotated to simulate lining wear. f. A salt solution per 6.2.2 must be maintained to a depth of 50.8 mm 6.4 mm (2.00 in 0.25 in) during the test. g. The exhaust air from the air chamber is to be piped into the solution reservoir. The force of the exhaust air, when directed i
21、nto the solution, must be capable of splashing and totally covering the brake adjuster with solution. 6.2 Durability test with contamination. An ambient temperature of 27 C 11 C (80 F 20 F) must be maintained. 6.2.1 Mount brake adjuster in a sealed environmental chamber capable of splashing and tota
22、lly covering the brake adjuster with solution during each application. 6.2.2 Mix a contaminated solution in the following proportions: a. 850 mLDistilled Water b. 100 gCoarse test dust (SAE J726b) c. 45 gSodium Chloride (99.9% Pure Granular or Flake) d. 5 gCalcium Chloride (Technical Flake Grade) 6.
23、3 General Test Set-Up 6.3.1 Position the brake adjuster as recommended by the manufacturer. SAE J1462 Revised OCT2011 Page 4 of 25 6.3.2 Establish a residual torque of 22.6 Nm 11.3 Nm (200 in-lbf 100 in-lbf) on the brake adjuster. 6.3.3 With the test torque applied and the brake adjuster adjusted to
24、 the previous requirements, position a shut-off device so that an overstroke of 6.4 mm (0.25 in) maximum at 152.4 mm (6 in) equivalent lever length will discontinue the test. 6.3.4 Apply the test torque against a resisting force resulting in a total deflection rate of 15 to 30 minutes (of a degree)
25、minimum per 113 Nm (1000 in-lbf) torque. 6.3.5 Establish the necessary time cycle controls to obtain the torque application and release requirements per the following (based on 30 cpm): a. Total cycle time of 4 s b. Maximum application time 1.00 s c. Minimum dwell time 1.00 s d. Release to residual
26、torque for balance of cycle time 6.3.6 To simulate lining wear, the worm wheel shall be rotated in the same direction that the load is applied at a rate of 0.5 degree per 250 cycles of test operation. 6.3.7 The brake adjuster test cycle shall be run in the following sequence at 9% of rated torque: 2
27、5 000 cycles with contaminationRest for 72 h 25 000 cycles without contamination 25 000 cycles with contaminationRest for 72 h 25 000 cycles without contamination 6.3.8 Record whether or not the brake adjuster triggered the shut-off device. 7. AUTOMATIC ADJUSTING FUNCTION DURABILITY TEST Conduct thi
28、s test at ambient temperature of 27 C 11 C (80 F 20 F). 7.1 General Test Setup 7.1.1 Position the brake adjuster as recommended by the manufacturer. 7.1.2 Establish a residual torque of 22.6 Nm 11.3 Nm (200 in-lbf 100 in-lbf) on the brake adjuster. 7.1.3 With the rated torque applied and the brake a
29、djuster adjusted to the previous requirements, position a shut-off device so that an overstroke of 6.4 mm (0.25 in) maximum will discontinue the test. The overstroke is measured from a point on the lever arm 152.4 mm (6 in) from the center of the worm wheel. 7.1.4 Apply the test torque against a res
30、isting force resulting in a total deflection rate of 15 to 30 minutes (of a degree) minimum per 113 Nm (1000 in-lbf) torque. 7.1.5 Establish the necessary time cycle controls to obtain the torque application and release requirements per the following:a. Total cycle time of 4.0 s b. Maximum applicati
31、on time of 1.0 s SAE J1462 Revised OCT2011 Page 5 of 25 c. Minimum dwell time 1.0 s d. Release to residual torque for balance of cycle time 7.2 Gear Set and Automatic Adjustment Integrity Test 7.2.1 To simulate lining wear, the worm wheel shall be rotated in the same direction that the load is appli
32、ed at a rate of 0.5 degrees per 160 cycles of test operation. 7.2.2 The brake adjuster test cycle shall be run in the following sequence: TABLE 1 - BRAKE ADJUSTER TEST CYCLE SEQUENCE Number of Cycles Percent of Rated Torque155 000 40 35 000 60 8500 80 1500 100 7.2.3 To simulate reline, where the bra
33、ke adjuster may be backed off to accommodate the new lining, rotate the worm wheel 50 degrees against the direction that the load is applied at 50 000 cycle increments. 7.2.4 Record whether or not the brake adjuster triggered the shut-off device. 7.2.5 Repeat 7.1.3. 8. DUST TEST 8.1 Cubical box insi
34、de measurement of 900 mm (35.43 in) on each side. 8.2 Dust 4.5 kg (9.9 lb) powdered cement (ASTM C 150-56) spread evenly over the bottom of the box. 8.3 General test setup is the same as 7.1 mounted within the box at least 150 mm (5.9 in) from any wall. 8.4 Cycle at 20% of rated torque for 5000 appl
35、ications and while cycling, the worm wheel shall be rotated in the same manner as 7.2.1. 8.5 During cycling, the dust shall be agitated at intervals of 15 min by compressed air or blower(s) by projecting a blast of air downward into the dust for a period of 2 s. The dust must be diffused throughout
36、the entire cube. 8.6 Record whether or not the brake adjuster triggered the shut-off device. 9. DURABILITY Conduct this test at ambient temperature of 27 C 11 C (80 F 20 F). 9.1 General Test Set-Up 9.1.1 Position the brake adjuster on the test fixture. 9.1.2 Adjust the brake adjuster so that with th
37、e rated torque (manufacturers recommended load x effective lever length) applied, the actuator pushrod is perpendicular (90 degrees 3 degrees) to the effective lever arm of the brake adjuster. SAE J1462 Revised OCT2011 Page 6 of 25 9.1.3 Establish a residual torque of 22.6 Nm 11.3 Nm (200 in-lbf 100
38、 in-lbf) on the brake adjuster. This simulates internal brake friction and brake return springs (where applicable). 9.1.4 With the rated torque applied and the brake adjuster adjusted to the previous requirements, position a shut-off device so that an equivalent overstroke of 6.4 mm (0.25 in) maximu
39、m at 152.4 mm (6 in) lever length will discontinue the test. 9.1.5 Apply the test torque per 9.2.2 against a resisting force resulting in a total deflection rate of 15 to 30 minutes (of a degree) minimum per 113 Nm (1000 in-lbf) torque. 9.1.6 Establish the necessary time cycle controls to obtain the
40、 torque application and release requirements per the following:a. Total cycle time of 4.0 s b. Maximum application time of 1.0 s c. Minimum dwell time 1.0 s d. Release to residual torque for balance of cycle time 9.2 Gear Set Integrity Test 9.2.1 Provide a reference mark on the adjusting shaft and w
41、orm wheel to assure return to original position after torque check 9.2.3. 9.2.2 The brake adjuster test cycle shall be run in the following sequence: TABLE 2 - BRAKE ADJUSTER TEST CYCLE SEQUENCE Number of Cycles Percent of Rated Torque 155 000 40 35 000 60 8500 80 1500 100 9.2.3 Measure and record t
42、he adjustment torque per the following schedule: Number of Cycles 50 000 100 000 155 000 190 000 198 500 200 000 Per the manufacturer recommendations, rotate adjusting shaft five turns in brake applied direction and ten turns in brake released direction. Record maximum torque in each direction. Retu
43、rn the adjusting shaft to the original position and continue the test. 9.3 Housing Integrity Test 9.3.1 After completion of 9.2.3, continue cycling at rated torque for 30 000 cycles. Repositioning or replacing of the gear set or its equivalent is permissible at any time during the housing test. 9.3.
44、2 Inspect for visible structural fractures through use of dye penetrant and record the findings. SAE J1462 Revised OCT2011 Page 7 of 25 10. DYNAMOMETER PERFORMANCE TEST 10.1 Purpose To evaluate external automatic brake adjuster dynamic performance under various application pressures/decelerations an
45、d brake operating temperatures. 10.2 Scope The dynamometer test is designed to look at the operational extreme conditions as well as the normal service conditions with respect to adjustment performance. The dynamometer test is not designed as an external automatic brake adjuster durability test. 10.
46、3 Test Hardware 10.3.1 Foundation Brake a. Double anchor pin cast spider b. Cam same rotation c. Camshaft based on a 12.7 mm (0.5 in) cam effective radius d. S-Cam centerline to brake adjuster centerline dimension of 293.6 mm 3.1 mm (11.56 in 0.125 in) e. Fabricated air chamber bracket assembly f. F
47、abricated brake shoe 10.3.2 Hub and Drum Assembly a. Cast iron drum 50.8 kg 2.3 kg (112 lb 5 lb) 10.3.3 Axle Spindle a. R-Series rear axle spindle 10 433 kg (23 000 lb) 10.3.4 Air Chamber a. Type 30/30 b. Rated stroke 64 mm (2.5 in) c. Attach Air Chamber Input-Output Curve 10.3.5 External Automatic
48、Brake Adjuster a. Brake Adjuster Length140 mm (5.5 in) 10.3.6 Brake Lining a. Capable of meeting the requirements of FMVSS-121 for a 10 433 kg (23 000 lb) rating 10.4 Drum Preparation 10.4.1 Measure drum diameter, open and closed sides, and record per Appendix A. SAE J1462 Revised OCT2011 Page 8 of
49、25 10.4.2 On the outside of the drum, mill or spot-face a flat smooth surface, perpendicular to the radial centerline (“A” Figure A1), on an area measured one-half the distance of the brake rubbing surface from the open side. This flat surface shall not partially interfere with any circumferential strengthening rib; h
