1、BRITISH STANDARD BS ISO 4927:2005 Road vehicles Elastomeric boots for cylinders for drum type hydraulic brake wheel cylinders using a non-petroleum base hydraulic brake fluid (Service temperature 120 C max.) ICS 43.040.40; 83.140.50 BS ISO 4927:2005 This British Standard was published under the auth
2、ority of the Standards Policy and Strategy Committee on 10 November 2005 BSI 10 November 2005 ISBN 0 580 46520 9 National foreword This British Standard reproduces verbatim ISO 4927:2005 and implements it as the UK national standard. The UK participation in its preparation was entrusted to Technical
3、 Committee PRI/69, Components and fluids for vehicle braking systems, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international publications referred to in t
4、his document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the necessary provisions of a c
5、ontract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposal
6、s for change, and keep UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the ISO title page, pages ii and iii, a blank page, pages 1 to 7 and a back cover. The B
7、SI copyright notice displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date Comments Reference number ISO 4927:2005(E)INTERNATIONAL STANDARD ISO 4927 Second edition 2005-06-15 Road vehicles Elastomeric boots for cylinders for drum typ
8、e hydraulic brake wheel cylinders using a non-petroleum base hydraulic brake fluid (Service temperature 120 C max.) Vhicules routiers Capuchons en caoutchouc pour cylindres de roue pour freins hydrauliques tambour utilisant un liquide de frein base non ptrolire (temprature maximale dutilisation 120
9、C) BS ISO 4927:2005ii BS ISO 4927:2005iii Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member
10、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 liaison with ISO, also take part in the work. ISO collaborates closely with the International Electr
11、otechnical 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 of technical committees is to prepare International Standards. Draft International Standards adopted
12、 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 is drawn to the possibility that some of the elements of this document may be the subject of patent
13、rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 4927 was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 2, Braking systems and equipment. This second edition cancels and replaces the first edition (ISO 4927:1978), which has been
14、 technically revised. blank 1 Road vehicles Elastomeric boots for cylinders for drum type hydraulic brake wheel cylinders using a non-petroleum base hydraulic brake fluid (Service temperature 120 C max.) 1 Scope This International Standard specifies performance tests for moulded rubber boots used at
15、 end closures on drum type wheel brake cylinders. These boots prevent the entrance of dirt and moisture which could cause corrosion and otherwise impair wheel brake operation. This International Standard is applicable to boots of both plain and reinforcement insert types, for fitting in wheel cylind
16、ers using a fluid in accordance with ISO 4925. It does not include requirements relating to chemical composition, tensile strength or elongation at brake of the rubber compound. It does not cover the strength of adhesion of rubber to the reinforcement in the insert type. The rubber material used in
17、these boots shall be suitable for operation in a temperature range of 40 C to + 120 C. 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
18、 the referenced document (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 1431-1:2004, Rubber, vulcanize
19、d or thermoplastic Resistance to ozone cracking Part 1: Static and dynamic strain testing ISO 4925, Road vehicles Specification of non-petroleum base brake fluids for hydraulic systems ISO 4926, Road vehicles Hydraulic brake system Non-petroleum base reference fluids ISO 4928:1980, Road vehicles Ela
20、stomeric cups and seals for cylinders for hydraulic braking systems using a non-petroleum base hydraulic brake fluid (Service temperature 120 C max.) 3 General requirements 3.1 Workmanship and finish The moulded boots shall be free from blisters, pin-holes, cracks, protuberances, embedded foreign ma
21、terial, or other physical defects, and shall conform to the dimensions specified on the drawings. BS ISO 4927:20052 3.2 Marking The identification mark of the manufacturer and other details as specified on the drawing shall be moulded into each boot where design permits. Each boot in conformity with
22、 this International Standard may also have the following mark: “ISO 4927”. 3.3 Packaging Boots shall be packaged to meet requirements specified by the purchaser. 3.4 Sampling The minimum lot on which complete specification tests shall be conducted for quality control testing, or the frequency of any
23、 specific type test used to control production, shall be agreed upon by the manufacturer and the purchaser. 4 Test requirements 4.1 Resistance to fluid at elevated temperature After the boots have been subjected to the test for resistance to fluids at elevated temperature as prescribed in 5.3, the c
24、hange in volume and the change in hardness shall be within the following limits: change in volume: 15 % to + 15 %; change in hardness: 10 IHRD to + 10 IRHD. 4.2 High temperature stroking performance After the high temperature stroking as specified in 5.4, a boot shall be free of flexure cracks which
25、 extend through the wall thickness, and shall fit tightly around the cylinder and push rod. 4.3 Low temperature stroking performance During the low temperature stroking as specified in 5.5, a boot shall not crack or separate from its assembled position on the cylinder or become loose on the push rod
26、. 4.4 Tension set performance After the tension set test prescribed in 5.6, boots shall show no more than 75 % tension set. 4.5 Heat resistance performance (static) After the heat resistance test as detailed in 5.7, a boot shall conform to the following requirements: a) no cracking shall occur when
27、the boot is flexed similarly to service conditions; b) the change in hardness shall be within the limits 5 IHRD to + 10 IRHD; c) no tackiness shall be evident after removal from the oven. BS ISO 4927:2005 3 4.6 Ozone resistance performance At the end of the 70 h exposure period as detailed in 5.8, t
28、est specimens shall be removed from the ozone chamber and examined under 2 magnification. The surface of the test specimens shall show no evidence of cracking, rupture or other deterioration. 5 Test procedures 5.1 Test specimens Specimens prepared for all tests shall be cut from the same general are
29、a of sample. In addition, hardness test specimens shall be prepared according to ISO 48. 5.2 Determination of hardness The method of determining rubber hardness shall be as described in ISO 48. Test each specimen submitted; record the range of IRHD. When the shape of the boot prevents using the meth
30、od described in ISO 48, an alternative method agreed between manufacture and purchaser may be substituted. In this case, correlation of the results obtained shall be made to IRHD as in ISO 48. 5.3 Resistance to fluids at elevated temperature 5.3.1 Apparatus 5.3.1.1 Circulating air oven as specified
31、in ISO 188 (3.2.2). 5.3.1.2 Screw-top, straight-sided, round glass jar, having a capacity of approximately 250 ml and inner dimensions of approximately 125 mm in height and 50 mm in diameter, and a tinned steel lid (no insert or organic coating). 5.3.2 Test specimens A section weighing approximately
32、 3 g to 5 g shall be cut from each of two boots. 5.3.3 Test fluid The brake fluid used for the test shall be the compatibility fluid in accordance with ISO 4926. 5.3.4 Procedure Rinse the specimens in isopropyl alcohol or its equivalent and wipe dry with a clean, lint-free cloth to remove dirt and p
33、acking debris. Do not allow the specimens to remain in the alcohol for more than 30 s. Determine and record the initial hardness of the test specimens (see 5.2). Determine the volume of each specimen in the following manner: Weigh each specimen in air (m 1 ) to the nearest 0,001 g and then weigh the
34、 specimen immersed in distilled water at room temperature (m 2 ). Quickly dip each specimen in alcohol and then wipe dry with a clean, lint-free cloth. Immerse two specimens completely in 75 ml of the test fluid in the glass jar and tightly cap the jar. Place the jar containing the specimen in the o
35、ven (5.3.1.1) at 120 C 2 C for a period of 70 h 2h. At the end of the heating period, remove the jar containing the specimen from the oven and allow to cool to BS ISO 4927:20054 23 C 5 C for 60 m to 90 m. At the end of the cooling period, remove the specimens from the jar and rinse in isopropyl alco
36、hol or its equivalent and wipe dry with a clean, lint-free cloth. Do not allow the specimens to remain in the alcohol for more than 30 s. After removing from the alcohol and drying, place each specimen in a separate, tarred, stoppered weighing bottle and weigh (m 3 ). Remove each specimen and weigh
37、it immersed in distilled water (m 4 ) to determine water displacement after hot fluid immersion. Determine the final volume and hardness of each specimen within 60 m after rinsing in alcohol. 5.3.5 Expression of results 5.3.5.1 Volume change shall be reported as a percentage of the original volume.
38、The percentage change in volume is given by the formula: ( ) ( ) () 3412 12 100 mmmm mm where m 1is the initial mass, in grams, in air; m 2is the initial apparent mass, in grams, in water; m 3is the mass, in grams, in air after immersion in test fluid; m 4is the apparent mass, in grams, in water aft
39、er immersion in test fluid. 5.3.5.2 Change in hardness shall be determined and recorded. 5.3.5.3 The specimens shall be examined for disintegration as evidenced by blisters or sloughing (carbon black). 5.4 High temperature stroking test 5.4.1 Apparatus 5.4.1.1 Circulating air oven as specified in IS
40、O 188 (3.2.2). 5.4.1.2 Stroking fixtures as shown in Figures 1 and 2 of ISO 4928. 5.4.2 Test specimen Two boots shall be used as test specimens. 5.4.3 Procedure Install two sample wheel cylinder boots on the cylinder for which they are designed, or equivalent. Then mount the cylinder in the actuator
41、 assembly, set to operate at (1000 100) strokes per hour with a stroke length of 4,8 mm 0,5 mm. Then place the cylinder assembly in the oven (5.4.1.1) and actuate for 70 h 2 h at 120 C 2 C. After the actuation of the assembly, remove it from the oven, allow to cool to room temperature, and examine t
42、he boots for flexure cracks and general appearance. BS ISO 4927:2005 5 5.5 Low temperature stroking test 5.5.1 Apparatus 5.5.1.1 Cold chamber, in which the test specimens are exposed to the low temperature, of sufficient size to contain the apparatus assembled with test specimens and so arranged as
43、to permit the operator to check and operate it without removal from the chamber. It shall be capable of maintaining a uniform atmosphere of cold dry air within the specified temperature range of 40 C to 43 C. 5.5.1.2 Stroking fixtures as shown in Figure 4 of ISO 4928. 5.5.2 Test specimens Two boots
44、shall be used as test specimens. 5.5.3 Procedure Install the sample wheel cylinder boots on the cylinder for which they are designed, or equivalent. Place the test boots and the test apparatus in the cold chamber (see 5.5.1.1) and expose them to a temperature range of 40 C to 43 C for 22 h 1 h. Afte
45、r 22 h 1 h of low temperature exposure, stroke them with the stroking test device for six strokes with a length of 4,8 mm 0,5 mm, at intervals of 30 s, without removal from the cold chamber. 5.6 Tension set test 5.6.1 Apparatus 5.6.1.1 Circular stretching mandrels, having a diameter which will expan
46、d by 0 3 15 % one or the other of the sealing ends attached to the wheel cylinder or to the actuating rod. The mandrel diameter (d 3 ) is calculated as 115 % of the moulded diameter of the chosen boot end. The moulded diameter shall be calculated from the average of two measurements made at right an
47、gles to one another on a contour projector. The mandrel shall be provided with a smooth lead-in chamfer to prevent cutting of the rubber and shall itself have a polished machine finished (16 Ra maximum). 5.6.1.2 Circulating air oven as specified in ISO 188 (3.2.2). 5.6.2 Test specimens Three boots s
48、hall be used as test specimens. 5.6.3 Procedure 5.6.3.1 Measure accurately and record the inside diameter (d 1 ) of the ends of three specimen boots. Assemble on the stretching mandrels (5.6.1.1). Place the assemblies in the oven (5.6.1.2) and age for 70 h 2 h at 120 C 2 C. Remove the assemblies and
49、 cool at room temperature for 1 h. Remove the boots. Allow to recover for between 30 m and 1 h. Again measure and record the diameter (d 1 ). 5.6.3.2 The tension set as a percentage of the original stretch deflection is given by the formula: 21 31 100 dd dd BS ISO 4927:20056 where d 1is the unaged inside diameter, in millimetres, of the boot; d 2is the aged inside diameter, in mil
