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/J2899_201312 SURFACE VEHICLE RECOMMENDED PRACTICE J2899 DEC2013 Issued 2013-12 Br
5、ake Adjustment Limit for Air Brake Actuators RATIONALE Field inspections to determine if air brakes on commercial vehicles are in an out-of-service condition are excessively complicated. Current method requires measurement of the air brake actuator diameter to determine the air brake actuator size.
6、A standard rated stroke for the air brake actuator size is then assumed unless a marking is found on the air brake actuator or ID tag that indicates a different rated stroke. Using the determined rated stroke and chamber size, a chart is referenced to provide the brake adjustment limit. The inspecto
7、r then confirms through measurement that the air brake actuator stroke is less than the determined brake adjustment limit. This method has many potential sources for error. A given actuator size may have several rated stroke options available. Charts converting air brake actuator diameters are not a
8、ccurately maintained. Air brake actuator diameters are not accurately measured. Air brake actuator manufacturers do not have standardized ID tag nomenclature making it difficult to read the rated stroke. Air brake actuators can be covered in paint or road debris hiding rated stroke information. Stro
9、ke rating clamp tags require clamps to mount to and must be located in a clamp clocking that is accessible to the inspector. This process can be simplified because the brake adjustment limit is a function of the rated stroke only. By putting a standardized rated stroke marking on the air brake actua
10、tor in a known location, the only conversion required is between the rated stroke marking to the brake adjustment limit. This document provides this recommended practice, reducing the likelihood of an inspector passing a vehicle that should be out of service or putting a vehicle out of service that
11、is within acceptable operating conditions. This new recommended practice also provides air brake actuator outside diameters developed from manufacturers data for reference to support air brake actuators manufactured prior to this recommended practice. The SAE Truck and Bus Brake Actuator Committee h
12、ave the largest representation of air brake actuator manufacturers making it the ideal source for such information. If this document gets adopted, SAE J1817 will be revised to identify long stroke air brake actuator markings only to avoid overlap. 1. SCOPE This SAE Recommended Practice applies to S-
13、CAM, Wedge, and Disc air brake actuators where the stroke can be measured without disassembly from the brake. 1.1 Purpose This document defines the air brake actuator rated stroke markings and its conversion to the air brake actuator rated stroke and brake adjustment limit. Copyright SAE Internation
14、al Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE INTERNATIONAL J2899 Issued DEC2013 Page 2 of 4 2. DEFINITIONS References to “Actuator” will mean “Air Brake Actuator” if not specified. 3. REFERENCES 3.1 Applicable Documen
15、ts 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. 3.1.1 SAE Publications Available from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323
16、(inside USA and Canada) or 724-776-4970 (outside USA), www.sae.org. SAE J1817 Long Stroke Air Brake Actuator Marking SAE J1953 Brake-Stroke Indicator Design Guideline for Cam or Disc Air Brake Actuators SAE J1469 Air Brake Actuator Test Procedure, Truck-Tractor, Bus, and Trailers 4. RATED STROKE MAR
17、KINGS Rated stroke markings identify the rated stroke and brake adjustment limit for an air brake actuator in a standardized format. 4.1 Location Rated stroke markings are to be located on the spring housing base for spring brakes or on the pressure housing base for service chamber brakes as shown i
18、n Figure 1, and marked per column “Rated Stroke Marking” as shown in Figure 2 4.2 Visibility The rated stroke marking is to be permanently stamped or embossed on the housing or on a corrosion resistant tag permanently affixed or bonded to the housing. The font height of the stroke marking is to be a
19、t least 3/8” (10mm) tall and at least 3 times the size of any other characters located on the same tag or within a 1/2” (12mm) from the stroke marking if located directly on the housing. The stamped impression/embossed character are to be a minimum of 0.012” (0.31mm) deep/high and visually confirmed
20、 it can be located and read if painted over with up to 0.008” (0.2mm) of paint. It must also be readable after completing the SAE J1469, section 14, salt spray test procedure. 4.3 Marking definition The corresponding rated stroke marking character matching the actuator rated stroke is shown in Figur
21、e 2. If the actuator has a different rated stroke than shown in Figure 2, then the Rated Stroke marking will be a two decimal number representing the brake adjustment limit based on 80% of the rated stroke rounded to the nearest 1/8” (3mm) increment. Copyright SAE International Provided by IHS under
22、 license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE INTERNATIONAL J2899 Issued DEC2013 Page 3 of 4 FIGURE 1 Rated Stroke Marking Actuator Rated Stroke Brake Adjustment Limit A 1.50” (38mm) 1.25” (32mm) B 1.75” (44mm) 1.38“ (35mm) C 2.00 “ (51mm) 1.
23、50” (38mm) D 2.25” (57mm) 1.75“ (44mm) E 2.50” (64mm) 2.00“ (51mm) F 3.00“ (76mm) 2.50“ (64mm) G 3.25” (83mm) 2.62“ (67mm) H 3.50” (89mm) 2.75“ (70mm) X.XX Other X.XX” FIGURE 2 5. AIR BRAKE ACTUATOR CLAMP BAND DIAMETER 5.1 Relationship between actuator clamp band outside diameter to air brake actuat
24、or size is shown in Figure 3. Reference Figure 4 for graphical definition of the service clamp band outside diameter. This diameter excludes the clamp fastener and is measured on a surface at least 1” (25mm) away from the clamp fastener. On actuators without clamps, the outside diameter is the maxim
25、um diameter on the housing at the location shown in Figure 4. Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE INTERNATIONAL J2899 Issued DEC2013 Page 4 of 4 5.2 Standard Type S-CAM Actuators Appl
26、ies to Specialty Type S-CAM Actuators* Standard Rated Stroke S-CAM Actuator clamp band outside diameter +/- 0.20“ (+/- 5mm) 6 5-7 1.50” (38mm) 4.63” (117mm) 9 8-10 1.75” (44mm) 5.38” (137mm) 12 11-13 1.75” (44mm) 5.81“ (148mm) 16 14-17 2.25” (57mm) 6.50“ (165mm) 20 18-21 2.25” (57mm) 6 .91“ (176mm)
27、24 22-26 2.50” (64mm) 7.34” (186mm) 30 27-32 2.50” (64mm) 8.22“ (209mm) 36 33-37 3.00“ (76mm) 9.13“ (232mm) FIGURE 3 FIGURE 4 SERVICE CHAMBER CLAMP BAND O.D. 6. NOTES 6.1 Marginal Indicia A change bar (l) located in the left margin is for the convenience of the user in locating areas where technical
28、 revisions, not editorial changes, have been made to the previous issue of this document. An (R) symbol to the left of the document title indicates a complete revision of the document, including technical revisions. Change bars and (R) are not used in original publications, nor in documents that con
29、tain editorial changes only. PREPARED BY THE SAE TRUCK AND BUS BRAKE ACTUATOR COMMITTEE OF THE SAE TRUCK AND BUS BRAKE AND STABILITY CONTROL STEERING COMMITTEE Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
