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 reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions. Copyright 2011 SAE International All rights reserved. No part of this publication m
3、ay 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 (outside U
4、SA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.orgSAE values your input. To provide feedbackon this Technical Report, please visit http:/www.sae.org/technical/standards/J2879_201107SURFACEVEHICLESTANDARDJ2879 JUL2011 Issued 2011-07 Automotive Hydraulic Brake Tube
5、Joints RATIONALE The Rationale for this specification is to create a more robust 90 degree double inverted flare (also known as 45 degree double inverted flare) joint for automotive brake tube joints. FOREWORD This Foreword is included with the intention of providing future users with information re
6、garding the background and rationale that guided the development of this standard. In late 2007, SAE received and accepted a proposal to work on improving the double inverted flare brake tube joint for automotive applications. A Task Force was formed consisting of 3 major OEMs, along with numerous t
7、ube, tube nut, and mating port suppliers. All agreed that the current joint should be evaluated for improvements based on current industry practices and knowledge of joint sealing. Sealing mechanisms for the joint were discussed. While it was commonly thought that the flare deformed, bending down to
8、 match the port, analysis of sectioned parts and X-rays of assembled parts did not prove out this mechanism. Instead, the majority of the deformation needed to seal comes from deformation of the port cone. Investigation of the specifications currently used for automotive applications (SAE J533, SAE
9、J512, SAE J527, and JASO F402:2001) revealed that the compatibility of dimensions and tolerances were not always optimized for joint sealing robustness. Also, the flare/nut/port specifications did not maintain the same relative geometry as the nominal tube size changed. The Task Force set out to bui
10、ld on the prior standards and improve these elements. The philosophy followed by the Task Force was as follows: Historically, joints with larger tube diameters exhibited less sealing robustness than those with smaller tube diameters resulting in higher installation torques for the larger diameter jo
11、ints - therefore the 3/16 in joint design was targeted as the baseline. As tube size increases, the features of the components should remain identical in size and interaction with each other, so that the cross-section of a component or an assembled joint changes only by shifting the center line to r
12、epresent the new diameter. Dimensions and tolerances of each component should be adjusted to relate to mating components in a way that reflects the evolution of understanding of the sealing mechanisms present in the joint. To promote treatment of the joint as a system, all three components of the jo
13、int are described in a single standard instead of separate component standards. SAE J2879 Issued JUL2011 Page 2 of 11 Joints that sealed well (particularly 3/16 in flares) suggested the following guidelines for updating the standards: The top of the cone seat of the port should contact toward the mi
14、ddle of the flare sealing surface. The tube nut should contact the back of the flare towards the outer diameter of the flare. Last full thread to top of cone is a critical port dimension for control of thread engagement. A minimum port depth is required to ensure proper thread engagement along with
15、all other dimensions. Starting then with the 3/16 in joint, the Task Force selected component dimensions based on all existing standards to optimize all the required component interactions. They then extrapolated by shifting the joint centerline to find the resultingdimensions for 1/4 in, 5/16 in, 4
16、.75 mm, 6.0 mm and 8.0 mm joints. These sizes were chosen because they are in common use in brake applications. Both metric tube sizes and English tube sizes were included in the specification. Users can differentiate this joint from other inverted flare joints by the presence of the 0.5 mm lead-in
17、on the tube nut. Thisfeature is unique from joints using SAE J512 or the JASO F402 standard. All dimensions in this specification have been developed to work together to optimize joint sealing and manufacturability, and modification is not recommended. Lessons Learned Current standards did not activ
18、ely control minimum thread engagement to the level that the Task Force members determined was important for the joint. Cone seat-to-thread and cone/flare/tube nut stackups were performed, scrutinized and revised over many months to prevent the tube nut from running out of threads when installed to t
19、he port and to ensure three threads minimum engagement between nut and port for the entire tolerance range. Note: running out of threads results in torque going into cutting new threads instead of generating clamp load. Cone seat wall thickness (port cone OD versus through hole) in this specificatio
20、n is consistent across all sizes. Some deformation of the cone when assembled has been historically acceptable and can improve sealing robustness. Flare thickness variation (TV) control is key to robust joint sealing. A flare with a large difference in thickness from maximum to minimum can result in
21、 the thick side being captured between nut and seat while the thin side has no contact. This situation is detrimental to sealing robustness. Current manufacturing methods limit the ability to specify this dimension to the level recommended for optimal joint sealing robustness (0.08 mm) in SAE Paper
22、2009-01-1029. Since 0.08 mm is not currently achievable 0.20 was included in this standard. Efforts should continue at flare manufacturers to improve flare TV capability as manufacturing methods evolve, in order to reduce TV tolerances. Traditional surface finish measurement of Ra or Rz was question
23、ed as to whether these were the best indicators of tube flare surface quality for sealing given the manufacturing process used to form tube flares. One large impression (e.g., 50 micron) in a sealing surface can cause a leak, however, Ra or Rz would be nearly unaffected by this type of defect becaus
24、e they average the values measured. It was concluded that Ra or Rz alone are not enough to prevent surface defects that could result in leaks. Rt was considered and eventually adopted based on benchmarking surface finish data on other types of flares. It measures the maximum peaks and valleys withou
25、t averaging, making it more sensitive to factors that affect the sealing of this joint. The back surface of the tube flare has had little dimensional control historically. The task force discussed adding a flat area for the tube nut to contact. However defining the surface and the ability to measure
26、 it in practice proved quite difficult.In order to not abandon the idea, a reference callout was added saying the area should be flat within specified gage diameters. Extensive stack-up and dimensional analysis was performed to establish common relationships between parts, across tube sizes, and wit
27、hin common supply base manufacturing practices. No rounding of dimensions was done for the final specification. This resulted in some non-symmetric tolerances for some dimensions. The reason for not rounding to create fully symmetric tolerances is so that future users can re-run dimensional analyses
28、 and reach the same conclusions or results as the Task Force that developed this specification. SAE J2879 Issued JUL2011 Page 3 of 11 1. SCOPE This document applies to 90 degree double inverted flares used on common sizes of automotive hydraulic brake tubes, and their associated tube nuts and mating
29、 ports. The intent of this standard is to replace the use of SAE J512 and SAE J533 for automotive hydraulic brake tube connections. 2. REFERENCES 2.1 Applicable Documents The following publications form a part of this specification to the extent specified herein. Unless otherwise indicated, the late
30、st 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 724-776-4970 (outside USA), www.sae.org.SAE J527 Brazed Double Wall Low-Carbon Steel Tubing 2.1.2 ANSI Pu
31、blications Available from American National Standards Institute, 25 West 43rd Street, New York, NY 10036-8002, Tel: 212-642-4900, www.ansi.org.ANSI/ASME B1.13M Metric Screw Threads M Profile 2.1.3 ASME Publications Available from American Society of Mechanical Engineers, 22 Law Drive, P.O. Box 2900,
32、 Fairfield, NJ 07007-2900, Tel: 973-882-1170, www.asme.org.ASME Y14.5M GD&T 2.1.4 DIN Publications Available from DIN Deutsches Institut fr Normung e. V. DIN German Institute for Standardization, Burggrafenstrae 6 / DIN-Platz, 10787 Berlin, Germany, Phone: +49 30 2601-0, Fax: +49 30 2601-1231, http:
33、/www.din.de/cmd?level=tpl-bereich&menuid=47562&cmsareaid=47562&languageid=enDIN 13 Metric Screw Threads 2.1.5 ISO Publications Available from American National Standards Institute, 25 West 43rd Street, New York, NY 10036-8002, Tel: 212-642-4900, www.ansi.org.ISO 965 Metric Screw Threads ISO 898-2 He
34、x sizes SAE J2879 Issued JUL2011 Page 4 of 11 2.2 Related Publications 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-
35、0001, Tel: 877-606-7323 (inside USA and Canada) or 724-776-4970 (outside USA), www.sae.org.Kapanowski, M. and Callahan, J., “The Effects of Flare Component Specifications on the Sealing of Double Inverted Flare Brake Tube Joints,“ SAE Technical Paper 2009-01-1029, 2009, doi:10.4271/2009-01-1029. Pli
36、assounov, S.I., “Fundamentals and Common Problems of Seal Integrity Robustness of Standardized Brake Tubing Threaded Connectors,“ SAE Technical Paper 2007-01-0557, 2007, doi:10.4271/2007-01-0557. 2.2.2 JASO Publications Available from JSAE, 10-2 Gobancho, Chiyoda-Ku, Tokyo, 102-0076 Japan, Tel: +81-
37、3-3262-8211(03-3262-8211 for domestic call) FAX: +81-3-3261-2204, E-mail: webmasterjsae.or.jp, http:/www.bookpark.ne.jp/jsae/book_e.aspJASO F402:2001 Automotive Parts - Flare Fittings 3. DEFINITIONS All GD&T in the details of Section 4 are based on ASME Y14.5M 4. TECHNICAL REQUIREMENTS Unless otherw
38、ise noted, all dimensions are in millimeters. This specification was developed based on automotive hydraulic brake component materials commonly used in 2010 (steel, aluminum, brass, and grey iron). Components, joints, and assembly processes developed using SAE J2879 must be validated by the user to
39、ensure that joint performance meets requirements specific to the application. 4.1 Double flares shall meet the requirements of Figure 1, Table 1, and the corresponding notes. 4.2 Tube nuts shall meet the requirements of Figure 2, Table 2, and the corresponding notes. 4.3 Ports shall meet the require
40、ment of Figure 3 and Table 3 or Figure 4 and Table 4 and the corresponding notes. Figure 3 and Figure 4 show two optional port designs. Figure 3 shows a chamfer version and Figure 4 shows counterbore version. Either port will work with the flares and nuts defined in this specification. The user and
41、manufacturer must decide which style to use. 4.4 No chatter marks permissible on any machined sealing surfaces. SAE J2879 Issued JUL2011 Page 5 of 11 FIGURE 1 - DOUBLE INVERTED TUBE FLARE TABLE 1 - DOUBLE INVERTED TUBE FLARE DIMENSIONS Flare Dimensions for Metric Tube Sizes - Measurements in millime
42、ters Tube O.D. (A) 0.08 Flare O.D. (B) +0.19-0.18 Flare I.D.(C) 0.15 Flare ThicknessVariation(on final part after forming) Nylon Coated Tube Max O.D. (D) REFERENCE: Back of flare must be flat within gage diameters (X) and (Y) 4.75 6.91 3.14 0.2 Max 5.20 5.59-6.49 6.0 8.16 4.39 6.45 6.84-7.74 8.0 10.
43、16 6.39 8.45 8.84-9.74Flare Dimensions for English Tube Sizes - Measurements in millimeters Tube O.D. (A) 0.08 Flare O.D. (B) +0.19-0.18 Flare I.D.(C) 0.15 Flare ThicknessVariation(on final part after forming) Nylon Coated Tube Max O.D. (D) REFERENCE: Back of flare must be flat within gage diameters
44、 (X) and (Y) 4.76 6.92 3.15 0.2 Max 5.21 5.60-6.50 6.35 8.51 4.74 6.80 7.19-8.09 7.94 10.10 6.33 8.39 8.78-9.68NOTES: 1. Appearance of Stripped Area: Stripped area to not expose base metal nor deform the base tubing to a diameter that is less than the minimum allowed diameter of the base tube. No th
45、reads, stringers, eyelashes, etc. are permitted anywhere on sealing surface or O.D. of flare after stripping and endforming. 2. Sealing Surface Quality: Surface finish must meet Rt 30 max, 0.8 mm minimum measurement length using a 2 micron stylus. Recommended measuring method is 4 axial measurements
46、 at 90 degree intervals around the flare sealing surface. There must be no surface impressions greater than 25 microns. 3. Coating: Throughout this standard, the term “Base Tube“ refers to a steel tube per SAE J527, with a zinc/aluminum/epoxy coating or other coating of similar dimensions. SAE J2879
47、 Issued JUL2011 Page 6 of 11 FIGURE 2 - TUBE NUT SAE J2879 Issued JUL2011 Page 7 of 11 TABLE 2 - TUBE NUT DIMENSIONS Tube Nut Dimensions for Metric Tube Sizes - Dimensions in millimeters NominalTube Size MaxTube Diameter A B(Recommended) C+0.13-0 D+0.1-0 E0.2 F6g Class of Fit After Coating/Plating G
48、 1 Base Tube 4.75 - PerISO 898-2, asappropriate for B 13 4.88 6.79 7.83 9.42 M10x1.0, 1.5 M12x1.0, 1.5 0.68min6.00 - 13 or 15 6.13 8.04 9.42 11.01 M12x1.0, 1.5 M14x1.5 8.00 - 15 8.13 10.04 11.01 M14x1.5Nylon CoatedTubes 4.75 5.20 See Steel 5.25See Steel 0.5min6.00 6.45 6.50 8.00 8.45 8.50 Tube Nut D
49、imensions for English Tube Sizes - Dimensions in millimeters NominalTube Size MaxTube Diameter A B(Recommended) C+0.13-0 D+0.1-0 E0.2 F6g Class of Fit After Coating/Plating G 1 Base Tube 4.76(3/16“) - PerISO 898-2, asappropriate for B 13 4.89 6.80 7.83 9.42 M10x1.0, 1.5 M12x1.0, 1.5 0.68min6.35(1/4“) - 13 or 15 6.48 8.39 9.42 11.01 M12x1.0, 1.5 M14x1.5 7.94(5/16“) - 15 8.07 9.98 11.01 M14x1.5N
