1、 g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58hydraulic braking systems using a non-petroleum base hydraulic brake fluid (Service temperature 120
2、 C max.)ICS 43.040.40; 83.140.50Road vehicles Elastomeric cups and seals for cylinders for BRITISH STANDARDBS ISO 4928:2006BS ISO 4928:2006This British Standard was published under the authority of the Standards Policy and Strategy Committee on 29 September 2006 BSI 2006ISBN 0 580 48733 4Amendments
3、issued since publicationAmd. No. Date Commentscontract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations.National forewordThis British Standard was published by BSI. It is the UK implementation of ISO 4928:2006.The UK
4、participation in its preparation was entrusted to Technical Committee PRI/69, Components and fluids for vehicle braking systems.A list of organizations represented on PRI/69 can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a Ref
5、erence numberISO 4928:2006(E)INTERNATIONAL STANDARD ISO4928Third edition2006-07-15Road vehicles Elastomeric cups and seals for cylinders for hydraulic braking systems using a non-petroleum base hydraulic brake fluid (Service temperature 120 C max.) Vhicules routiers Coupelles et joints en caoutchouc
6、 pour cylindres de dispositifs de freinage hydrauliques utilisant un liquide de frein base non ptrolire (Temprature maximale dutilisation 120 C) BS ISO 4928:2006ii BS ISO 4928:2006iiiContents Page Foreword iv 1 Scope . 1 2 Normative references . 1 3 Terms and definitions. 1 4 General requirements. 2
7、 4.1 Workmanship and finish 2 4.2 Marking 2 4.3 Packaging 2 4.4 Sampling 2 5 Test requirements. 2 5.1 Resistance to fluid at elevated temperature 2 5.2 Precipitation 2 5.3 Wheel cylinder seals heat pressure stroking 2 5.4 Master cylinder seals heat pressure stroking . 3 5.5 Low-temperature performan
8、ce 4 5.6 Oven ageing 4 5.7 Corrosion. 4 5.8 Storage corrosion test 5 6 Test procedures 5 6.1 Resistance to fluid at elevated temperature Dimensional test 5 6.2 Precipitation test. 7 6.3 Wheel cylinder seals heat pressure stroking 8 6.4 Master cylinder seals heat pressure stroking . 9 6.5 Low-tempera
9、ture performance 11 6.6 Oven ageing 12 6.7 Hardness determination. 12 6.8 Corrosion test . 13 6.9 Storage corrosion test 14 BS ISO 4928:2006iv Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of pre
10、paring International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in
11、 liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task
12、 of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention
13、 is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 40421 was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 2, Braking and systems
14、 equipment. This third edition cancels and replaces the second edition (ISO 4928:1980), which has been technically revised. BS ISO 4928:20061Road vehicles Elastomeric cups and seals for cylinders for hydraulic braking systems using a non-petroleum base hydraulic brake fluid (Service temperature 120
15、C max.) 1 Scope This International Standard specifies performance tests of brake cups and seals for hydraulic braking systems for road vehicles; it does not include requirements relating to chemical composition, tensile strength and elongation of the rubber compound. Disc brake seals are not covered
16、 by this International Standard. This International Standard is applicable to moulded seals (cups or double-lipped type gland seals), 60 mm in diameter and smaller, compounded from high temperature-resistant rubber, for use in hydraulic actuating cylinders using road vehicle non-petroleum base hydra
17、ulic brake fluid conforming to the requirements of ISO 4925. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (
18、including any amendments) applies. ISO 48, Rubber, vulcanized or thermoplastic Determination of hardness (hardness between 10 IRHD and 100 IRHD) ISO 188:1998, Rubber, vulcanized or thermoplastic Accelerated ageing and heat resistance tests ISO 1250, Mineral solvents for paints White spirits and rela
19、ted hydrocarbon solvents ISO 4925, Road vehicles Specification of non-petroleum-base brake fluids for hydraulic systems ISO 4926, Road vehicles Hydraulic braking systems Non-petroleum base reference fluids 3 Terms and definitions For the purposes of this document, the following terms and definitions
20、 apply. 3.1 sloughing release of carbon black on the surface of the rubber 3.2 scoring formation of grooves in the rubber parallel to the direction of travel of the piston or seal 3.3 scuffing visible erosion of the outer surface of the rubber BS ISO 4928:20062 4 General requirements 4.1 Workmanship
21、 and finish Seals shall be free from blisters, pin-holes, cracks, protuberances, embedded foreign material or other physical defects which can be detected by thorough inspection, and shall conform to the dimensions specified on the drawings. 4.2 Marking The identification mark of the manufacturer an
22、d other details as specified on drawings shall be moulded into each seal. Each seal in conformity with this International Standard may also have the following mark: “ISO 4928”. 4.3 Packaging Seals shall be packaged to meet requirements specified by the purchaser. 4.4 Sampling The minimum lot on whic
23、h complete specification tests shall be conducted for quality control testing, or the frequency of any specific type test used to control production, shall be agreed upon by the manufacturer and the purchaser. 5 Test requirements 5.1 Resistance to fluid at elevated temperature After being subjected
24、to the test for resistance to compatibility fluid at elevated temperature as prescribed in 6.1, the seals shall conform to the requirements specified in Table 1, and shall show no excessive disintegration as evidenced by blisters or sloughing. Table 1 Requirements for fluid resistance at elevated te
25、mperature (120 C) Characteristics Permitted change Volume Outside diameter, lip Outside diameter, base Hardness From 0,0 % to + 20,0 % From 0,0 % to + 5,75 % From 0,0 % to + 5,75 % From 15 IRHD to 0 IRHD 5.2 Precipitation Not more than 0,3 % sediment by volume shall be formed in the centrifuge tube
26、after the seals have been tested as specified in 6.2. 5.3 Wheel cylinder seals heat pressure stroking 5.3.1 General Wheel cylinder seals, when tested by the procedure specified in 6.3, shall meet the performance requirements specified in 5.3.2 to 5.3.6. BS ISO 4928:200635.3.2 Lip diameter change The
27、 minimum lip diameter of wheel cylinder seals after the stroking test shall be greater than the wheel cylinder bore by the minimum dimensions specified in Table 2. Table 2 Lip diameter change of wheel cylinder seals Dimensions in millimetres Diameter of wheel cylinder bore Minimum excess over bore u
28、 19,05 19,05; u 25,4 25,4; u 38,1 38,1; u 60 0,40 0,50 0,65 0,75 5.3.3 Leakage No constant dampness past the seals or fluid discoloration of the filter paper on two or more inspections shall occur. 5.3.4 Corrosion Pistons and cylinder bore shall not show corrosion as evidenced by pitting to an exten
29、t discernible to the naked eye, but staining or discoloration shall be permitted. 5.3.5 Change in hardness Rubber seals shall not decrease in hardness by more than 15 IRHD when tested in accordance with the procedure as specified in 6.7. 5.3.6 Condition of test seals Wheel cylinder seals shall not s
30、how excessive deterioration such as scoring, scuffing, blistering, cracking, chipping (heel abrasion) or change in shape from original appearance. 5.4 Master cylinder seals heat pressure stroking 5.4.1 General Master cylinder seals, when tested by the procedure specified in 6.4, shall meet the perfo
31、rmance requirements specified in 5.4.2 to 5.4.6. 5.4.2 Lip diameter change The minimum lip diameter of master cylinder seals after the stroking test shall be greater than the master cylinder bore by the minimum dimensions specified in Table 3. Table 3 Lip diameter change of master cylinder seals Dim
32、ensions in millimetres Diameter of master cylinder bore Minimum excess over bore u 19,05 19,05; u 25,4 25,4; u 38,1 38,1; u 60 0,30 0,40 0,50 0,65 BS ISO 4928:20064 5.4.3 Leakage The same requirement as specified for wheel cylinder seals shall be applied (see 5.3.3). 5.4.4 Corrosion The same require
33、ment as specified for wheel cylinder seals shall be applied (see 5.3.4). 5.4.5 Change in hardness The same requirement as specified for wheel cylinder seals shall be applied (see 5.3.5). 5.4.6 Condition of test seals The same requirement as specified for wheel cylinder seals shall be applied (see 5.
34、3.6). 5.5 Low-temperature performance 5.5.1 Leakage No leakage of fluid shall occur when seals are tested according to the procedure specified in 6.5.1. 5.5.2 Bend test The seal shall not crack and shall return to approximately its original shape within 1 min when tested according to the procedure s
35、pecified in 6.5.2. 5.6 Oven ageing 5.6.1 General Seals, when tested according to the procedure specified in 6.6, shall meet the requirements specified in 5.6.2 and 5.6.3. 5.6.2 Change in hardness The change in hardness shall be within the limits of 5 IRHD. 5.6.3 Condition of test seals The seal shal
36、l show no evidence of deterioration, or change in shape from original appearance. 5.7 Corrosion 5.7.1 General Seals, when tested according to the procedure specified in 6.8, shall meet the requirements specified in 5.7.2 and 5.7.3. 5.7.2 Corrosion of metal strips The seals shall not cause corrosion
37、exceeding the limits shown in Table 4. The metal strips outside of the area where the strips are in contact shall be neither pitted nor roughened to the extent discernible to the naked eye, but staining or discoloration is permitted. BS ISO 4928:20065Table 4 Permissible change in mass of corrosion t
38、est strips Test strips Permissible change in mass mg/cm2of surface Tinned iron Steel Aluminium Cast iron Brass Copper Zinc 0,2 0,2 0,1 0,2 0,4 0,4 0,4 5.7.3 Fluid-water mixture characteristics The fluid-water mixture at the end of the test shall show no jellying at 23 C 5 C. No crystalline type depo
39、sits shall form and adhere to either the glass wall or the surface of metal strips. The fluid-water mixture shall contain no more than 0,2 % sediment by volume. 5.8 Storage corrosion test After twelve cycles in the humidity cabinet when operated according to the procedure specified 6.9, there shall
40、be no evidence of corrosion adhering to or penetrating the wall of the cylinder bore that was in contact with the test seal. Slight discoloration (staining) or any corrosion or spots away from the contact surface of the test seals may be permissible. 6 Test procedures 6.1 Resistance to fluid at elev
41、ated temperature Dimensional test 6.1.1 Apparatus and material 6.1.1.1 Micrometer, shadowgraph or other suitable apparatus, to measure accurately to 0,02 mm. 6.1.1.2 Glass container, of capacity approximately 250 ml and diameter 50 mm, which can be tightly sealed. 6.1.1.3 Chemical balance, capable o
42、f weighing to 1 mg. 6.1.1.4 Oven, uniformly heated dry air type, conforming to the requirements for Method B of ISO 188:1998. 6.1.1.5 Two glass-stoppered weighing bottles, of adequate mouth size to hold the seals under test. 6.1.1.6 Isopropyl or ethyl alcohol, of 95 % (by volume) reagent grade for w
43、ashing purpose. 6.1.2 Test specimens Two seals shall be used for testing at 120 C. BS ISO 4928:20066 6.1.3 Procedure Rinse the cups in the alcohol (6.1.1.6) and wipe dry with a clean, lint-free cloth to remove dirt and packing debris. Do not leave the seals in the alcohol for more than 30 s. Measure
44、 the lip and base diameters to the nearest 0,02 mm, taking the average of two readings at right angles to one another. Take care when measuring the diameters before and after ageing that the measurements are made in the same manner and at the same locations. Determine and record the initial hardness
45、 of the test seals. (See 6.7 and Figure 3.) Determine the volume of each seal in the following manner: weigh the seals in air (m1) to the nearest 0,001 g and then weigh the seals immersed in distilled water at room temperature (m2). Quickly dip each specimen in alcohol and then blot dry with filter
46、paper free of lint and foreign material. Immerse two seals completely in 75 ml 1 ml of compatibility reference fluid as defined in ISO 4926, in the glass container (6.1.1.2) and seal the container to prevent vapour loss. Place the container in the oven (6.1.1.4) set at 120 C 2 C for a period of 70 h
47、 2 h. At the end of the heating period, remove the container from the oven and allow the seals to cool in the container at 23 C 5 C for 60 min to 90 min. At the end of the cooling period, remove the seals from the container and rinse in the alcohol and wipe dry with a clean, lint-free cloth. Do not
48、allow the seals to remain in the alcohol for more than 30 s. After removal from the alcohol and drying, place each seal in a separate, tarred, stoppered weighing bottle (6.1.1.5) and weigh (m3). Remove each seal from its weighing bottle and weigh immersed in distilled water (m4) to determine water d
49、isplacement after hot fluid immersion. Make all weighings to the nearest 0,001 g. Determine the final volume, dimensions and hardness of each seal within 60 min of rinsing in the alcohol. 6.1.4 Expression of results 6.1.4.1 Volume change Volume change V shall be reported as a percentage of the original volume. The change in volume is given by the equation: V =()( )()34 1212100mm mmmmwhere m1is the initial mass in air, in grams; m2is the initial apparent mass in water, i
