GB Translated English of Chinese Standard: GB NATIONAL STANDARD OF THE

Transcription

1 Translated English of Chinese Standard: GB GB ICS Q 69 NATIONAL STANDARD OF THE PEOPLE S REPUBLIC OF CHINA GB Replacing GB Brake linings for automobiles 汽车用制动器衬片 Issued on: September 18, 2008 Implemented on: September 10, 2009 Issued by: General Administration of Quality Supervision, Inspection and Quarantine of the People s Republic of China; Standardization Administration of the People s Republic of China. Page 1 of 17

2 Table of Contents Foreword Scope Normative references Terms and definitions Classification Technical requirements Test methods Inspection rules Marks, packaging, transportation and storage Page 2 of 17

3 Foreword The Sections 5.3 and 5.4 of this Standard are mandatory, while other sections are recommended. The consistent degree between this Standard and JIS D (confirmed in 2006) Brake linings and pads for automobiles is not equivalent. This Standard replaces GB Brake linings for automobiles. Compared with the GB , the major modifications of this Standard are as follows: ADD the Terms and definitions. MODIFY the technical specifications given in Tables 3, 4, 5 and 6 of the Section 5.3 in this Standard. The details are as follows: a) MODIFY the allowable deviation of the coefficient appointed in Table 3 from ± 0.12 to ± Respectively MODIFY the wear from 2.00, 3.00 to 1.50, b) MODIFY the coefficient of friction in Table 4 from 0.15~0.70 to 0.20~0.70. MODIFY the allowable deviation of the coefficient appointed from ± 0.12 to ± MODIFY the wear from 2.00 to c) MODIFY the coefficient of friction in Table 5 from 0.15~0.70 to 0.20~0.70. Respectively MODIFY the allowable deviation of the coefficient appointed from ± 0.12, ± 0.14 to ± 0.10, ± MODIFY the wear from 3.00 to d) MODIFY the coefficient of friction in Table 6 from 0.20~0.70 to 0.25~0.70. Respectively MODIFY the allowable deviation of the coefficient appointed from ± 0.12, ± 0.14 to ± 0.10, ± Respectively MODIFY the wear from 2.50, 3.50 to 2.00, ADD the technical requirements and corresponding test methods for the shear strength, impact strength, swell, and compressive strain. RECOMPILE the inspection rules. ADD the contents and items of the type inspection. This Standard was proposed by China Building Materials Federation. Page 3 of 17

4 Brake linings for automobiles 1 Scope This Standard specifies the terms and definitions, classification, technical requirements, test methods, inspection rules, marks, packaging, transportation and storage of the brake linings for automobiles. This Standard applies to the brake linings for automobiles (hereinafter referred to as linings ). 2 Normative references The provisions in the following documents become the provisions of this Standard through reference in this Standard. For dated references, the subsequent amendments (excluding corrections) or revisions do not apply to this Standard. However, parties who reach an agreement based on this Standard are encouraged to study if the latest versions of these documents are applicable. For undated references, the latest versions apply to this Standard. GB/T Sampling procedures for inspection by attributes Part 1: Sampling schemes indexed by acceptance quality limit (AQL) for lot-by-lot inspection (GB/T , ISO :1999, IDT) GB/T Road vehicles Brake linings Shear test procedure for disc brake pad and drum brake shoe assemblies (GB/T , ISO 6312:2001, IDT) GB/T Road vehicles Brake linings Effects of heat on dimensions and form of disc brake pads Test procedure (GB/T , ISO 6313:1980, IDT) GB/T Road vehicles Brake linings Compressive strain test method (GB/T , ISO 6310:2001, IDT) JB/T 7498 Coated abrasives Abrasive paper JC/T 1065 Constant speed friction test machine 3 Terms and definitions The following terms and definitions apply to this Standard. Page 5 of 17

5 3.1 Coefficient of friction (μ) It refers to the ratio OF friction (f) TO the normal force (F) applied to the test specimen. 3.2 Coefficient appointed (μa) It refers to the value of friction coefficient agreed upon by the supply and requisitioning parties of linings. 3.3 Wear (V) It refers to the ratio OF wear volume loss TO friction work of linings under the specified conditions. 3.4 Shear strength It refers to the ratio OF the force which is parallel to the rear plate of the disc brake pad or the edge surface of the drum brake shoe, and can completely shear the lining materials with the rear plate or shoe plate TO the shear geometric area of the lining materials. 3.5 Swell It refers to the ratio OF the increment of the heated thickness of the lining TO the initial thickness of the lining. 3.6 Impact strength It refers to the ratio OF the impact energy consumed during the fracture of the test sample TO the cross-sectional area at the fracture of the test sample. 4 Classification According to the applications, the linings are divided into four categories. SEE Table 1. Table 1 Lining Classification Classification Applications Classification Applications Class I For the parking brakes Class III For the drum brakes of mediumsized and heavy vehicles Class II For the drum brakes of mini and light vehicles Class IV For the disc brakes Page 6 of 17

6 5.6 Coefficient of thermal expansion For the Class IV linings, the coefficient of thermal expansion at 400 C ± 10 C shall not be greater than 2.5%. 5.7 Compressive strain For the Class IV linings, the compressive strain at room temperature shall not be greater than 2%, while the compressive strain at 400 C ± 10 C shall not be greater than 5%. 6 Test methods 6.1 Appearance quality inspection USE the visual observation and knocking methods for appearance quality inspection. 6.2 Dimension measurement USE a vernier caliper with the accuracy of 0.02mm to measure the width and thickness dimensions. 6.3 Friction property test Test specimen PREPARE two test specimens from the working surface of the same lining The dimensions of the test specimens are 25mm 25mm. The allowable deviation is within the range of -0.2mm ~ 0mm The thickness of the test specimens is within the range of 5mm to 7mm. The thickness difference between two test specimens shall below 0.2mm. If the product thickness is less than 5mm, its original thickness will apply Test equipment The test equipment shall conform to the provisions specified in the standard JC/T Test conditions The pressure applied to the test specimens shall be 0.98MPa. Page 9 of 17

7 The disk materials shall conform to the provisions specified in the JC/T USE the abrasive paper with the granularity of P240 specified in the JB/T 7498 to process the disk surfaces, so as to ensure that there are no defects on the disk surfaces, such as obvious scratches, rust, pits, etc The friction direction shall be the same with that of the linings Test procedures PLACE two test specimens in the support arm of the test specimens. CONDUCT the test according to the following order: RUN in the test specimens below 100 C, until the contact surface is up to more than 95%. USE a micrometer with the accuracy of 0.01mm to measure the thickness of the test specimens. DETERMINE the thickness after the test specimens cool down to room temperature. MEASURE 5 points on each test specimen. TAKE the arithmetic mean When the test temperature is at 100 C, DETERMINE the friction when the disk rotates at 5,000rpm according to the requirements specified in the Section of this Standard. After the friction test, MEASURE the thickness of the test specimens according to the Section of this Standard At the test temperature of 150 C, 200 C, 250 C, 300 C and 350 C, respectively CONDUCT the same test according to the Section of this Standard. However, the maximum test temperatures of various linings shall conform to the provisions specified in Tables 3 to 6. When conducing the test at various temperatures, the disk temperature shall rise up to the specified test temperature within 1,500rpm. The increase of the disk temperature mainly relies on the friction heat of the test specimens. When the disk temperature cannot come up to the specified test temperature within 1,500rpm, it is allowed to use an auxiliary heating device After determining the maximum test temperature, DECREASE the disk temperature by 50 C every time from the maximum test temperature, DETERMINE the friction when the disk rotates at 1,500rpm afterwards, until the disk temperature decreases to 100 C. The temperature decrease from the upper stage to the next stage shall be accomplished within 500 revolutions After the test, USE the visual observation method to inspect the appearance of the test specimens and the disk friction surface Calculation CALCULATE the coefficient of friction at various test temperatures according to the Equation (1): Page 10 of 17

8 DIVIDE the actual delivered linings with the same materials and specifications into one batch. When the batch size is too large, it is allowed to divide the linings into several small batches Sampling schemes USE the random sampling method to inspect the appearance and dimension deviation of the linings. According to the GB/T , USE the single sampling scheme for normal inspection. Respectively TAKE the special inspection level and AQL value as S-4 and 2.5. The determination of the sample size required for different batches, and qualified or unqualified batches shall conform to the provisions specified in Table 8. Table 8 Sample Size and Determination Regulations Unit: piece Batch size Sample size Acceptance number Rejection number ~ ~1,200 1,201~10,000 > 10, Result determination For the friction property, shear strength (bonding type), swell, compressive strain, and impact strength, CONDUCT random sampling according to the provisions specified in Table 9. If the friction property and impact strength of each sample conform to the requirements of this Standard, DETERMINE this item of this batch of products as qualified. If the arithmetic mean of the shear strength (bonding type), swell and compressive strain of all the samples conform to the requirements of this Standard, DETERMINE this item of this batch of products as qualified If any one of the above-mentioned inspection items is unqualified, DOUBLE the samples for re-inspection. If the re-inspection results conform to the requirements of this Standard, DETERMINE this item as qualified. If any one of the re-inspection items is still unqualified, DETERMINE this item of this batch of products as unqualified. Table 9 Sample Size Unit: piece Batch size Friction Shear strength Impact Compressive Swell property (bonding type) strength strain 10, > 10, Page 16 of 17

9 7.3.3 If all the inspection items are qualified, DETERMINE this batch of products as conforming products. If any one of the inspection items is unqualified, DETERMINE this batch of products as non-conforming products. 8 Marks, packaging, transportation and storage 8.1 Marks The non-working surfaces of the linings shall be painted with the manufacturing plant s name or trademark, manufacturing date or batch number The four sides surrounding each packing case (box) for the linings shall be respectively possessed of the product name, model and specifications, manufacturing plant s name and/or trademark, address, product quantity, coefficient appointed, packaging inspection date, and this Standard No. 8.2 Packaging The linings shall be closely and tidily packed in clean and dry, solid and durable cases (boxes) The linings with the same model and specifications shall be packed in each packing case (box). It is also allowed to pack the complete sets of the supplied linings as the users required Each packing case (box) shall have the product qualification certificate. 8.3 Transportation During transportation, the linings shall not be damaged, or stained by oil and water. 8.4 Storage The linings shall be stored in the ventilated and dry rooms with flat ground. END Page 17 of 17