1、 Collection of SANS standards in electronic format (PDF) 1. Copyright This standard is available to staff members of companies that have subscribed to the complete collection of SANS standards in accordance with a formal copyright agreement. This document may reside on a CENTRAL FILE SERVER or INTRA
2、NET SYSTEM only. Unless specific permission has been granted, this document MAY NOT be sent or given to staff members from other companies or organizations. Doing so would constitute a VIOLATION of SABS copyright rules. 2. Indemnity The South African Bureau of Standards accepts no liability for any
3、damage whatsoever than may result from the use of this material or the information contain therein, irrespective of the cause and quantum thereof. ICS 21.100.10 ISBN 0-626-16229-7 SANS 12306:2005Edition 1ISO 12306:1994Edition 1SOUTH AFRICAN NATIONAL STANDARD Plain bearings Measurement of wall thickn
4、ess of thin-walled half-bearings and thin-walled bushes This national standard is the identical implementation of ISO 12306:1994 and is adopted with the permission of the International Organization for Standardization. Published by Standards South Africa 1 dr lategan road groenkloof private bag x191
5、 pretoria 0001 tel: 012 428 7911 fax: 012 344 1568 international code + 27 12 www.stansa.co.za Standards South Africa SANS 12306:2005 Edition 1 ISO 12306:1994 Edition 1 Table of changes Change No. Date Scope Abstract Describes in accordance with SANS 12301 the checking methods and measuring equipmen
6、t used for measuring the total wall thickness of thin-walled half-bearings and thin-walled bushes in the finished state. It is not applicable to thermoplastic bushes. Keywords bearing bushes, bearings, dimensional measurements, gauges, instruments, measurements, measuring, plain bearings, thickness,
7、 unsplit bushes, wrapped bushes. National foreword This South African standard was approved by National Committee StanSA TC 5120.02, Bearings, in accordance with procedures of Standards South Africa, in compliance with annex 3 of the WTO/TBT agreement. INTERNATIONAL STANDARD ISO 12306 First edition
8、1994-02-15 Plain bearings - Measurement of wall thickness of thin-walled half-bearings and thin-walled bushes Paliers lisses - Mesurage de Iepaisseur de paroi des demi-coussinets minces et des bagues minces Reference number ISO 12306:1994(E) ISO 12306:1994(E) Foreword ISO (the International Organiza
9、tion 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. Esch member body interested in a subject for which a technical committee has been established
10、has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take patt in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Dr
11、aft 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. International Standard ISO 12306 was prepared by Technical Committee ISO/TC
12、 123, Plain bearings, Subcommittee SC 5, Quality analysis and as- surance. Annex A forms an in for information only. tegral patt of this International Standard. Annex B is 0 ISO 1994 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utrlized in any for
13、m or by any means, electronie or mechanical, including photocopying and microfilm, without pe rmissi on in writing from the publisher. International arg anization for Standardiza tion Case Postale 56 l CH-121 1 Geneve 20 l Switzerland Printed in Switzerland INTERNATIONAL STANDARD 0 ISO ISO 12306:199
14、4(E) Plain bearings - Measurement of wall thickness of thin-walled half-bearings and thin-walled bushes 1 Scope This International Standard describes in accordance with ISO 12301 the checking methods and measuring equip- ment used for measuring the total wall thickness of thin-walled half-bearings a
15、nd thin-walled bushes in the finished state. lt is not applicable to thermoplastic bushes. NOTE 1 All dimensions in this International Standard are given in millimetres. 2 Normative references The following Standards contain provisions which, through reference in this text, constitute provisions of
16、this International Standard. At the time of publication, the editions indicated were valid. All Standards are subject to revision, and Parties to agreements based on this International Standard at-e encouraged to investigate the possi- bility of applying the most recent editions of the Standards ind
17、icated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 3547:1976, Plain bearings - Wrapped bushes - Dimensions, tolerantes and methods of checking. ISO 3548: 1978, Plain bearings - Thin-walled half bearings - Dimensions, tolerantes and me thods of che
18、cking. ISO 4379: 1993, Plain bearings - Copper alloy bushes. ISO 6864: 1984, Plain bearings - Thin-walled flanged half bearings - Dimensions, tolerantes and methods of checking. ISO 12301: 1992, Plain bearings - Quality control techniques and inspection of geometrical and material quality characteri
19、stics. 3 Definition For the purposes of this International Standard, the following definition applies. 3.1 total wall thickness, s,: Radial distance between the opposing measuring Points at the inside and the outside surface diameter. (See figure 1.) 1 ISO 12306:1994(E) 0 ISO ($3 ) l -w-m t - Figure
20、 1 - Total wall thickness, stet 4 Symbols and units For the purposes of this International Standard, the Symbols and units are as given in table 1. Symbol aC B DO F* Pn n Stet u UE Ax i a Qx Table 1 - Symbols and units Parameter Measuring distance Width Outside diameter Checking load (measuring pin)
21、 Number of test pieces Total wall thickness Uncertainty of measurement (confidence level of 95 %) Uncertainty of measurement of measuring equipment Differente in measured values between first and second readings Arithmetic mean of hx Standard deviation Standard deviation of AX SI unit mm mm mm N mm
22、mm mm mm mm mm mm 5 Purpose of checking In Order to guarantee the required bearing clearance and consequently the operational efficiency of the plain bearing unit, it is necessary to keep to the wall thickness tolerantes specified in ISO 3547, ISO 3548, ISO 4379 and ISO 6864. 6 Checking methods (see
23、 annex A) 6.1 Measuring principle The gauging axis of the measuring pins shall be in the radial direction and at a right angle to the outside surface of the test piece in Order to find the minimum value of the wall thickness. The measured values may be recorded by a Single measurement or by sum meas
24、urement, which are symbolically represented in figure 2. I 0 ISO ISO 12306:1994(E) a) Single measurement by contact b) Sum measurement by contact/non-contact (mechanical/electronic gauge) (electronic/pneumatic gauge) Figure 2 - Measuring principle of wall thickness measurement The presence of lubric
25、ating holes, oil pockets, oil grooves, markings or special chamfers may require deviation from the measuring lines and measuring Points specified in the following and shall be agreed upon separately. Any wall thickness not conforming to the specified values on account of the manufacturing process, b
26、ecause of deformation of the bearing backing in the area of marking or at non-load bearing places of wrapped bushes, shall be defined separately. 6.2 Line measurement around the circumference Continuous measurement of the wall thickness around the circumference shall be carried out at the measuring
27、lines specified in figure3 and table 2. iamf er Figure 3 - Position of measuring lines 3 ISO 12306:1994(E) Table 2 - Measuring line distances ac Width Measuring distancel) Number of measuring lines M . B aC B SO 8 and B/2 3 / 1) Esch measuring line distance ac is specified from the beginning of the
28、sliding surface. 6.3 Line measurement in the axial direction Continuous measurement of the wall thickness shall be carried out in the axial direction at the measuring lines specified in figures 4 and 5 for widths of BG 50 mm and outside diameter Do 50 mm and DO 150 mm, the measurement method shall b
29、e subject to agreement be- tween the manufacturer and customer. 6.3.1 Half-bearings See figure 4 /-K Measuring lines M Ml M2 M3 Figure 4 - Three-Iine measuring scheme for half-bearings with DO 6 150 mm (ff3 ISO ISO 12306:1994(E) 6.3.2 Bushes See figure 5. This method of measurement may be used for u
30、nsplit as weil as for wrapped bushes, of ground or calibrated design. Split Position of wrapped bush 7 Measuring lines M I % Ml M2 M3 Figure 5 - Three-line measuring scheme for unsplit or wrapped bushes with DO 90 mm and D, 150 mm, the measurement method shall be subject to agreement between the man
31、ufacturer and customer. The measuring line distance, a, shall be taken from table2. 6.4.1 Half-bearings See figures 6 to 8. ISO 12306:1994(E) 0 = measuring Point P Figure 6 - Six-Point measuring scheme for half-bearings with B 150 5 * 0,2 5 * 0,2 1) For metallic or plastic inside surface. 7.3 Accura
32、cy data The selection of the measuring equipment and measuring pins is dependent on the measuring method and the wall thickness tolerante to be tested. The limiting values of measurement of the uncertainty of measurement of the measuring equipment are given in table4. The determination of the uncet-
33、tainty of measurement is given in 8.1. Table 4 - Limiting values for the measuring equipment Outside diameter Uncertainty of measurement of measuring equipment DO UE 1 DO80 0,002 I 8OD& 150 0,003 I I 15OD,500 l 0,004 I 8 Checking of measuring equipment The measuring equipment should be checked for u
34、ncertainty of measurement at a frequency specified by the User, based on the type of equipment and on experience from previous Checks. 8.1 Determination of the uncertainty of measurement, u (see annex B) Twenty-four bushes or half-bearings shall be measured twice each (after each reinsertion of the
35、piece) within a short period of time by means of the same measuring equipment including the measuring instrument to be checked, and by the same person at the same checking place. The differente, AX, between the two measurements determined with correct signs gives the Standard deviation, CT (calculat
36、ed by Computer) from the equation: 9 ISO 12306:1994(E) 0 ISO Provided that the values derive from a normal distribution and that a is considered to be a sufficiently exact as- sessed value for the Standard deviation of the lot, a random component of the measurement uncertainty u for a Single result
37、measured by means of this measuring instrument is (for a confidence level of 95 %): u 4% =v- ll- 2 The value u is compared to the limiting value uE. 10 , 0 ISO ISO 12306:1994(E) Annex A (normative) Indication of the checking method on drawings A. 1 Half-bearings The drawing shall include the measuri
38、ng scheme and whether it was “Point measurement” or “line measurement”. A.2 Bushes The drawing shall include the measuring scheme and whether it was “Point measurement” or “line measurement”. Either the inside diameter or the wall thickness shall be indicated as the dimension to be checked, but not
39、both. The following instruction shall be respected for the dimensioning: “The drawing shall indicate the external diameter and wall thickness, or the external diameter and internal di- ameter. In no case shall both the wall thickness and the internal diameter be given as dimensions to be checked.” A
40、.3 Unequal Wall thickness Where the bearing design requires unequal wall thicknesses, this shall be indicated as in figureA.1, together with the corresponding checking method in accordance with A.1 and A.2. Figure A.l - Dimensioning for unequal wall thickness 11 ISO 12306:1994(E) 0 ISO I Test piece
41、No. l 1st reading I 2nd reading u111erence ex Df3IW and 2nd readir I n:u,-, . L- een 1st w Annex B (informative) Determination of uncertainty of measurement Tabulation of test results for checking the thickness of bushes or half-bearings to determine the uncertainty of measurement, U, according to 8
42、.1 should be as shown in table B.l. Table B.l - Test results Values in micrometres l I I I I _ - I I I 13 I I I 15 I I I Ah I I I I I I 17 I 19 I I I I 20 l 1 I I 22 I I I 21 I 23 24 I I 1 uti= u 4% z-c Ir 2 J 12 Standards South AfricaThis s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .
