1、 WORLDWIDE ENGINEERING STANDARDS Material Specification GMW14721 EPDM Elastomer for Hydraulics Brake Cuff Copyright 2011 General Motors Company All Rights Reserved October 2011 Originating Department: North American Engineering Standards Page 1 of 4 1 Scope This standard covers the materials and per
2、formance of elastomeric brake cuffs for wheel brake cylinder and master brake cylinder. 1.1 Material Description. Materials covered by this specification are divided into two types: 1.1.1 Type A. Ethylene Propylene Diene Terpolymer (EPDM) cover for +125 C permanent and +150 C peak temperatures. 1.1.
3、2 Type B. Drawing defined (e.g., using SAE J200 or ASTM D2000 line callout). 1.2 Symbols. Not applicable. 1.3 Typical Applications. Not applicable. 1.4 Remarks. Not applicable. 2 References Note: Only the latest approved standards are applicable unless otherwise specified. 2.1 External Standards/Spe
4、cifications. ASTM D2000 ISO 1817 ISO 48 ISO 23529 ISO 188 SAE J200 2.2 GM Standards/Specifications. GMW3059 GMW14393 GMW3221 GMW15386 GMW3356 2.3 Additional References. TMC003 Material Safety Data Sheet guidance documents (available at ). 3 Requirements 3.1 Requirements on Test Specimens. Reference
5、GMW3221. 3.2 Resources. 3.2.1 Test Samples. Unless otherwise specified, the shape, size and number of test pieces shall be in accordance with the relevant test method. Unless otherwise specified, samples are finished parts or to be taken from finished parts. If not otherwise stated, mechanical prope
6、rties in delivery state and after heat or fluid immersion are to be tested at +23 C and with the same test methods. 3.2.2 Conditioning. Conditioning shall be as specified in the relevant test method. 3.2.3 Equipment. Conforming to the relevant test methods. Diameter of the cuffs are to be measured c
7、ontact-less (by microscope, shadowgraph or other suitable device) to 0.01 mm before and after storage in brake fluid at the same points and with two measurements at right angles to one another. Change is calculated from the arithmetic mean of the two measurements before and after brake fluid immersi
8、on. 3.2.4 Calibration. The test facilities and equipment shall be in good working order and shall have a valid calibration label. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW14721 Copyright 2011 General Motor
9、s Company All Rights Reserved October 2011 Page 2 of 4 3.2.5 Alternatives. Alternative test facilities and equipment may also be used. However, all measuring variables as specified in this specification shall be determined correctly with respect to its physical definition. 3.2.6 Facilities. Conformi
10、ng to the relevant test methods. 3.2.7 Deviations. Deviations from the requirements of this standard shall have been agreed upon. Such deviations shall be specified on component drawings, test certificates, reports, etc. 3.3 Material and Performance Requirements. Material and performance requirement
11、s are summarized in Table 1. Table 1: Material and Performance Properties Property Test Method Unit Value Hardness Type A ISO 48 Method M IRHD 75 5 Type B As specified on drawing/math data file Shore A As specified on drawing Age Resistance (Heat Aging) Type A ISO 188 Method B, 168 -2 h at +125 3 C
12、Change in Hardness Change in Appearance IRHD 5 maximum No evidence of blistering, cracking or change in shape from original form. Type B As specified on drawing/math data file As specified on drawing Resistance to Brake Fluid Type A ISO 1817, to GMW3356, 125 3 C, 168 -2 h Change in Volume Change in
13、outside diameter lip Change in outside diameter base Precipitation in brake fluid after 24 h at +23 5 C % % % % 0 to +10 maximum 0 to +5.75 maximum 0 to +5.75 maximum 0.3 by volume maximum No crystalline precipitations allowed Type B As specified on drawing/math data file % As specified on drawing C
14、old Resistance Type A ISO 23529, -45 3 C; 22 +1 h Test piece is whole part Bending test =90 No cracks Part must have returned to original shape after 1 minute Type B As specified on drawing/math data file As specified on drawing Corrosion Resistance Type A Test is performed on complete brake or mast
15、er cylinder assemblies. Clean all parts with ethanol and moisten the parts with brake fluid GMW3356 before assembling. Fill the cylinder with brake fluid and store for 336 -2 h at +70 3 C (for wheel brake cylinder leave inlet bore open and close bleeding screw.) After cooling down to +23 5 C, cylind
16、ers are disassembled and evaluated. No evidence of rubber adhesion of the test seals shall appear during disassembly. Metal parts must be free from corrosion or other precipitations. Minor precipitations in the brake fluid are allowed. Type B As specified on drawing/math data file As specified on dr
17、awing Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW14721 Copyright 2011 General Motors Company All Rights Reserved October 2011 Page 3 of 4 Property Test Method Unit Value Cycling Humidity Storage Corrosion Te
18、st Type A Use assemblies as described in Corrosion Resistance, but without filling with brake fluid. Store the assemblies with inlet bore downwards to the following cycle. 16 -0.5 h at +40 3 C and 95 3% relative humidity, followed by 8 -0.5 h at +23 5 C and 95 3% relative humidity. Continue the 24 h
19、 cycle for a total of 12 cycles. Interruption is only possible after a whole cycle. Until continuing the cycle, parts must be stored at +23 5 C and 95 3% relative humidity. After 12 cycles, cylinders are disassembled and evaluated. No corrosion is allowed in the contact area between sealing and cyli
20、nder wall. Corrosion or staining beyond the contact area is to be ignored. Type B As specified on drawing/math data file As specified on drawing Durability Tests GMW14393 Cold Testing of Wheel Brake Cylinders GMW15386 Brake Caliper Assembly Technical Specification (only tests that affect durability
21、of rubber parts) 4 Manufacturing Process Cuffs must be free from blisters, pin-holes, cracks, protuberances, embedded foreign material, or other physical effects which could adversely affect serviceability and usage detrimentally. 5 Rules and Regulations 5.1 Legal Regulations. All materials must sat
22、isfy applicable laws, rules, regulations and recommendations valid in the country of usage. 5.2 Language. In the event of conflict between the English and domestic language, the English language shall take precedence. 5.3 Inspection and Rejection. Samples of components or materials released to a GM
23、material specification shall be tested for conformity with the requirements of this material specification and approved by the responsible Engineering department prior to commencement of delivery of bulk supplies. A new approval must be received for any changes, e.g., properties, manufacturing proce
24、ss, location of manufacture, etc. If not otherwise agreed, all testing and documentation normally required for initial release must be completed. It is the responsibility of the supplier to inform the customer in a timely manner, without solicitation, and to include documentation of all modification
25、s of materials and/or processes and to apply for a new release. If not otherwise agreed, all release tests shall be repeated and documented by the supplier prior to commencement of delivery of non-conforming bulk supplies. In individual cases, a shorter test can be agreed to between the responsible
26、Engineering department and the supplier. 5.4 Initial Source Approval. No shipments shall be made by any supplier until representative initial production samples have been approved by the appropriate Materials Engineering department(s) as meeting the requirements of this specification. 5.5 Material S
27、afety Data Sheets/Safety Data Sheets (MSDS/SDS). For new product submissions, or when a change in chemical composition of an existing product has occurred, a complete copy of the Material Safety Data Sheet/Safety Data Sheet must be submitted in compliance with the Globally Harmonized System of Class
28、ification and Labeling of Chemicals (GHS) requirements or other country-specific MSDS/SDS requirements. In addition, product MSDS/SDS submissions must be in compliance with specific country General Motors TMC003 Material Safety Data Sheet/Safety Data Sheet guidance documents where available. 5.6 All
29、 materials supplied to this standard must comply with the requirements of GMW3059, Restricted and Reportable Substances for Parts. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW14721 Copyright 2011 General Moto
30、rs Company All Rights Reserved October 2011 Page 4 of 4 6 Approved Sources Engineering qualifications of an approved source are required for this standard. Only sources listed in the GM Materials File (MATSPC) under this standard number have been qualified by Engineering as meeting the requirements
31、of this standard. For other GM locations, the responsible Engineering group should be contacted to obtain the approved source in that individual country. 7 Notes 7.1 Glossary. Not applicable. 7.2 Acronyms, Abbreviations, and Symbols. EPDM Ethylene Propylene Diene Terpolymer GHS Globally Harmonized S
32、ystem IRHD International Rubber Hardness Degree MATSPC Global repository of GM Approved Materials for corresponding GM Engineering Standards MSDS Material Safety Data Sheet SDS Safety Data Sheet 7.3 Samples of a new material quality and/or a new supplier must fulfill wear tests in the vehicle determ
33、ined by the responsible engineering group without objections. 8 Coding System This standard shall be referenced in other documents, drawings, etc., as follows: Material per GMW14721 Type “X“, where X = material type as defined in Section 1.1. 9 Release and Revisions This standard was originated in O
34、ctober 2005. It was first approved by the Global Elastomers Team in May 2006. It was first published in November 2006. Issue Publication Date Description (Organization) 1 NOV 2006 Initial publication. 2 OCT 2011 5 Year Refresh (Global Elastomers Team) Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
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