1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 21940-32:2012Mechanical vibration RotorbalancingPart 32: Shaft and fitment key conventionBS ISO 21940-32:2012 BRITISH STANDARDNational forewordThis British Standard is the
2、 UK implementation of ISO21940-32:2012. It supersedes BS 7130:1989 which is withdrawn. The UK participation in its preparation was entrusted to TechnicalCommittee GME/21/5, Mechanical vibration, shock and conditionmonitoring - Vibration of machines.A list of organizations represented on this committ
3、ee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Institution 2012. Published by BSI StandardsLimited 2012 ISBN 978 0 580 71415 3 ICS 21.120.10;
4、 21.120.40 Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 30 April 2012. Amendments issued since publicationDate Text affectedBS ISO 21940-32:2012Reference number
5、ISO 21940-32:2012(E)ISO 2012INTERNATIONAL STANDARD ISO21940-32First edition2012-03-15Mechanical vibration Rotor balancing Part 32: Shaft and fitment key convention Vibrations mcaniques quilibrage des rotors Partie 32: Convention relative aux clavettes darbres et aux lments rapports BS ISO 21940-32:2
6、012ISO 21940-32:2012(E) COPYRIGHT PROTECTED DOCUMENT ISO 2012 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from eit
7、her ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2012 All rights reservedBS ISO 21940-32:2012IS
8、O 21940-32:2012(E) ISO 2012 All rights reserved iiiContents Page Foreword ivIntroduction vi1 Scope 12 Normative references 13 Terms and definitions . 14 Half-key convention 15 Marking . 36 Implementation of the half-key convention 4Annex A (normative) Specifications for the half-key convention 5Anne
9、x B (informative) Practical considerations for making half-keys and usage of keys . 7Annex C (informative) Comparison between shaft and fitment key conventions 13Bibliography 16BS ISO 21940-32:2012ISO 21940-32:2012(E) iv ISO 2012 All rights reservedForeword ISO (the International Organization for St
10、andardization) 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 body interested in a subject for which a technical committee has been established has the rig
11、ht 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 Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International
12、 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 by the technical committees are circulated to the member bodies for voting. Publication as a
13、n 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 rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO
14、21940-32 was prepared by Technical Committee ISO/TC 108, Mechanical vibration, shock and condition monitoring, Subcommittee SC 2, Measurement and evaluation of mechanical vibration and shock as applied to machines, vehicles and structures. This first edition of ISO 21940-32 cancels and replaces ISO
15、8821:1989, of which it constitutes an editorial revision. The main change is deletion of statements relating to the implementation date, transition period and key convention usage in the past. ISO 21940 consists of the following parts, under the general title Mechanical vibration Rotor balancing: Pa
16、rt 1: Introduction1) Part 2: Vocabulary2) Part 11: Procedures and tolerances for rotors with rigid behaviour3) Part 12: Procedures and tolerances for rotors with flexible behaviour4) Part 13: Criteria and safeguards for the in-situ balancing of medium and large rotors5) Part 14: Procedures for asses
17、sing balance errors6)1) Revision of ISO 19499:2007, Mechanical vibration Balancing Guidance on the use and application of balancing standards 2) Revision of ISO 1925:2001, Mechanical vibration Balancing Vocabulary 3) Revision of ISO 1940-1:2003, Mechanical vibration Balance quality requirements for
18、rotors in a constant (rigid) state Part 1: Specification and verification of balance tolerances 4) Revision of ISO 11342:1998, Mechanical vibration Methods and criteria for the mechanical balancing of flexible rotors 5) Revision of ISO 20806:2009, Mechanical vibration Criteria and safeguards for the
19、 in-situ balancing of medium and large rotors 6) Revision of ISO 1940-2:1997, Mechanical vibration Balance quality requirements of rigid rotors Part 2: Balance errors BS ISO 21940-32:2012ISO 21940-32:2012(E) ISO 2012 All rights reserved v Part 21: Description and evaluation of balancing machines7) P
20、art 23: Enclosures and other protective measures for balancing machines8) Part 31: Susceptibility and sensitivity of machines to unbalance9) Part 32: Shaft and fitment key convention10)7) Revision of ISO 2953:1999, Mechanical vibration Balancing machines Description and evaluation 8) Revision of ISO
21、 7475:2002, Mechanical vibration Balancing machines Enclosures and other protective measures for the measuring station 9) Revision of ISO 10814:1996, Mechanical vibration Susceptibility and sensitivity of machines to unbalance 10) Revision of ISO 8821:1989, Mechanical vibration Balancing Shaft and f
22、itment key convention BS ISO 21940-32:2012ISO 21940-32:2012(E) vi ISO 2012 All rights reservedIntroduction It is often impossible or economically unreasonable to balance rotors with fitments after they have been assembled; the rotor components which also may originate from different suppliers are th
23、erefore balanced separately. An appropriate balance tolerance is applied to each component so that, when shaft and fitment(s) are coupled together, the rotor assembly meets the required balance tolerance and/or vibration limit. For coupling the fitment(s) to the shaft, different methods are applied,
24、 a very common one uses keys. If, however, a different key convention has been used when balancing the shaft than that one used for balancing the fitment(s), it is quite likely that the rotor assembly has a balance error influencing its residual unbalance. There are three methods, or key conventions
25、, for balancing shafts and fitments coupled together with keys: full-key convention; half-key convention; no-key convention. This part of ISO 21940 unifies the key conventions used throughout the world and gives instructions on a marking of components balanced in accordance with the key convention a
26、pplied. When consistently used, it results in compatibility of shafts and fitments so that they can be balanced by different suppliers and, after being assembled, the balance tolerance and/or vibration limit for the rotor assembly is met. BS ISO 21940-32:2012INTERNATIONAL STANDARD ISO 21940-32:2012(
27、E) ISO 2012 All rights reserved 1Mechanical vibration Rotor balancing Part 32: Shaft and fitment key convention 1 Scope This part of ISO 21940 specifies one convention for balancing the individual components (shaft and fitments) of a keyed rotor assembly. This provides compatibility of all balanced
28、components so that when they have been assembled the overall balance tolerance and/or vibration limit for the rotor assembly is met. This part of ISO 21940 specifies that half-keys be used when balancing the individual components of a keyed rotor assembly. It also specifies a marking of the componen
29、ts balanced in accordance with the key convention used. This part of ISO 21940 applies to rotors balanced in a balancing machine, in their own bearings or in situ. The key convention can also be applied when measuring the residual unbalance and/or vibration of rotors with keyways, but to which fitme
30、nts have not yet been assembled. In addition to applying to keys of constant rectangular or square cross-section mounted parallel to the shaft centreline, this part of ISO 21940 also applies to keys mounted on tapered shaft surfaces, to woodruff, gibhead, dowel and other special keys. The principle
31、of the half-key convention is applied as is appropriate to the particular shape and location of the special key. 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 referen
32、ces, the latest edition of the referenced document (including any amendments) applies. ISO 1925, Mechanical vibration Balancing Vocabulary1)3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 1925 apply. 4 Half-key convention This part of ISO 21940 speci
33、fies that the half-key convention be followed. According to this convention a half-key shall be used in the keyway of the shaft having one keyway while balancing the shaft without the fitment. A complementary half-key shall be used while balancing the corresponding fitment on a balancing mandrel, pr
34、ovided the mandrel has no keyways. If the mandrel has keyways, the methods described in A.1.3 shall be followed. If at one cross-section, shaft and fitment each have two keyways the methods described in A.1.4 shall be followed. The axial location of the centre of gravity of the half-key should be th
35、e same as that of the full key in the final assembly. NOTE Table 1 shows examples of various types of shaft keyways and full keys of constant rectangular or square cross-section. 1) To become ISO 21940-2 when revised. BS ISO 21940-32:2012ISO 21940-32:2012(E) 2 ISO 2012 All rights reservedTable 1 Exa
36、mples of types of shaft keyways and keys Type Configuration of keyway Name of keyway Configuration of keyaName of key A Round/round end Square/square endRound/round end B Round/square end Round/square end Square/square endRound/round end C Sled runner Square/square enda Full-key cross-section Rectan
37、gular Square l Length of the keyway d Depth of the keyway BS ISO 21940-32:2012ISO 21940-32:2012(E) ISO 2012 All rights reserved 3Practical considerations for making and usage of half-keys are given in Annex B. A contoured half-key set is shown in Figure 1. Key 1 half-key for the fitment 2 half-key f
38、or the shaft Figure 1 Contoured half-key set The use of the half-key convention provides a uniform method for balancing shafts and fitments joined together by keys. It eliminates balance errors and therefore unnecessary residual unbalance and/or vibration which can be caused by the use of different
39、key conventions, and avoids the creation of an internal bending moment in the assembly (as would be caused by the use of full keys during balancing of the shaft). For more information on the differences between the key conventions, see Annex C. 5 Marking 5.1 The end face of the shaft adjacent to the
40、 keyway shall be permanently marked with the letter H to indicate that balancing was performed using the half-key convention. Permanent marking using metal stamps or vibratory engravers is recommended, but a permanent or indelible ink may also be used. If the shaft end face is too small for marking,
41、 the bottom of the keyway may be used. 5.2 The face of the fitment adjacent to the keyway shall be permanently marked with the letter H to indicate that balancing was performed using the half-key convention. The letter should be readily visible when the fitment is joined to the shaft. Permanent mark
42、ing using metal stamps or vibratory engravers is recommended, but a permanent or indelible ink may also be used. 5.3 The marking of the shaft and the fitment with the letter H may only be omitted if confusion as to which key convention was used is unlikely. 5.4 When balancing a replacement shaft or
43、fitment, the known mating part of which has not been balanced using the half-key convention, it is permissible to balance the replacement component with the key convention of the existing mating part. In this special case, both components shall be permanently marked with an identification letter cor
44、responding to the key convention used, as follows: a) components balanced using the full-key convention (see C.1.2) shall be marked with the letter F adjacent to the keyway; BS ISO 21940-32:2012ISO 21940-32:2012(E) 4 ISO 2012 All rights reservedb) components balanced using the no-key convention (see
45、 C.1.4) shall be marked with the letter N adjacent to the keyway. NOTE 1 For the fitment, the balancing procedures in accordance with the full-key convention and the no-key convention are identical. Marking is done as ordered. NOTE 2 If fitments are balanced for being put on stock, these fitments ma
46、y be marked either with F or with N. But since the full-key convention is in use more often, these fitments generally are marked with F. 6 Implementation of the half-key convention All manufacturers of original parts and processed components shall comply with the half-key convention of balancing and
47、 mark each newly manufactured shaft and fitment with the letter H. NOTE Some International Standards prescribe that the half-key convention be followed, e.g. IEC 60034-141. Change-over of equipment in service to the half-key convention with proper marking of the shaft and fitment(s) during a repair
48、balancing operation is encouraged. In any case, a marking shall be added (see Clause 5). BS ISO 21940-32:2012ISO 21940-32:2012(E) ISO 2012 All rights reserved 5Annex A (normative) Specifications for the half-key convention A.1 Principal specifications for the half-key convention A.1.1 The specificat
49、ions given in A.1.2 to A.1.4 apply to one cross-section. A.1.2 For a shaft with a single keyway, a half-key is required for the keyway. A.1.3 For a fitment with a single keyway, one of the following requirements shall be met: a) when the mandrel has no keyway: use one half-key; b) when the mandrel has two identical keyways 180 opposite each other: use one full key and one half-key of equal length; c) when the mandrel has a single keyway: first use one half-key
