1、BRITISH STANDARD BS ISO 53:1998 Cylindrical gears for general and heavy engineering Standard basic rack tooth profile ICS 21.200BSISO53:1998 This British Standard, having been prepared under the directionof the Engineering SectorBoard, was published underthe authority of the Standards Board and come
2、s intoeffect on 15 October 1998 BSI 05-1999 ISBN 0 580 30452 3 National foreword This British Standard reproduces verbatim ISO 53:1998 and implements it as the UK national standard. The UK participation in its preparation was entrusted to Technical Committee MCE/5, Gears, which has the responsibilit
3、y to: aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. A list of o
4、rganizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Sta
5、ndards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Stan
6、dard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, theISO title page, pages ii to iv, pages 1 to 4 and a back cover. This standard has been updated (see copyright date) and may have had amendm
7、ents incorporated. This will be indicated in the amendment table on the inside front cover. Amendments issued since publication Amd. No. Date CommentsBSISO53:1998 BSI 05-1999 i Contents Page National foreword Inside front cover Foreword iii Text of ISO53 1ii blankBSISO53:1998 ii BSI 05-1999 Contents
8、 Page Foreword iii 1 Scope 1 2 Normative references 1 3 Terms and definitions 1 4 Symbols and units 1 5 Standard basic rack tooth profile 1 Annex A (informative) Basic rack recommendations for various applications 4 Figure 1 Standard basic rack tooth profile and mating standard basic rack tooth prof
9、ile 2 Figure A.1 Basic rack tooth profile with a chosen undercut 4 Table 1 Symbols and units 1 Table 2 Standard basic rack proportions 2 Table A.1 Basic rack tooth profiles 4BSISO53:1998 BSI 05-1999 iii Foreword ISO (the International Organization for Standardization) is a worldwide federation of na
10、tional 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 right to be represented on that committee. Intern
11、ational 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. Draft International Standards adopted by the technical comm
12、ittees 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 53 was prepared by Technical Committee ISO/TC60, Gears. This second edition cancels and replaces the firs
13、t edition (ISO 53:1974), which has been technically revised. Annex A of this International Standard is for information only. Descriptors: Gears, cylindrical gears, racks (gears), teeth (mechanics), profiles, characteristics.iv blankBSISO53:1998 BSI 05-1999 1 1 Scope This International Standard speci
14、fies the characteristics of the standard basic rack tooth profile for cylindrical involute gears (external or internal) for general and heavy engineering. This International Standard applies to the standardized modules specified in ISO54. The defined profile does not take into account the possible c
15、ut-off of the height of internal teeth. This height is to be calculated for each case. The standard basic rack tooth profile defined in this International Standard constitutes a geometrical reference for a system of involute gears in order to fix the sizes of their teeth. It does not constitute a de
16、finition of a cutter, but a cutter may be defined from this standard basic rack tooth profile in order to realize a conforming profile. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At th
17、e time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO
18、maintain registers of currently valid International Standards. ISO 54:1996, Cylindrical gears for general and for heavy engineering Modules. ISO1122-1:1998, Vocabulary of gear terms Part1: Definitions related to geometry. 3 Terms and definitions For the purposes of this International Standard, the t
19、erms and definitions given in ISO 1122-1 and the following apply. 3.1 standard basic rack tooth profile tooth profile normal section through the teeth of a basic rack which corresponds to an external gear with number of teeth z = and diameter d = Figure 1 NOTEThe tooth of the standard basic rack too
20、th profile is bounded by the tip line at the top and by the parallel root line at the bottom. The fillet between the straight part of the profile and the root line is a circular arc with a radius equal to fP . 3.2 mating standard rack tooth profile rack tooth profile symmetrical to the standard basi
21、c rack tooth profile about the datum line P-P and displaced by half a pitch relative to it Figure 1 4 Symbols and units SeeTable 1. Table 1 Symbols and units 5 Standard basic rack tooth profile 5.1 The characteristics of the standard basic rack tooth profile are given in Figure 1 and Table 2. Additi
22、onal basic rack recommendations and applications are given in Annex A. 5.2 The standard basic rack tooth profile with module m has a pitch p = ; m. 5.3 The flanks of the standard basic rack tooth profile are straight for the section h aPplus h FfP . Symbol Description Unit c P Bottom clearance betwe
23、en standard basic rack tooth and mating standard basic rack tooth mm e P Spacewidth of standard basic rack mm h aP Addendum of standard basic rack tooth mm h fP Dedendum of standard basic rack tooth mm h FfP Straight portion of the standard basic rack tooth dedendum mm h P Tooth depth of standard ba
24、sic rack mm h wP Common depth of standard basic rack and mating standard basic rack tooth mm m Module mm p Pitch mm s P Tooth thickness of standard basic rack tooth mm U FP Size of undercut mm FP Angle of undercut degrees P Pressure angle degrees fP Fillet radius of the basic rack mmBSISO53:1998 2 B
25、SI 05-1999 Table 2 Standard basic rack proportions 5.4 On the line P-P the tooth thickness is equal to the space-width, i.e. half the pitch. where 5.5 The flanks of the standard basic rack tooth profile are inclined at the pressure angle, P , to a line normal to the datum line P-P. 5.6 The tip line
26、and the root line are respectively parallel to the datum line P-P at distances of h aPand h fP . 5.7 The active tooth depth, h wp , of the standard basic rack tooth profile and the mating standard basic rack tooth profile is equal to 2h aP . 5.8 The dimensions of the standard basic rack tooth profil
27、e use line P-P as the base datum. 5.9 The fillet radius of the standard basic rack, fP , is determined by the standard clearance, c p . For a basic rack, where P= 20, c P , # 0,295 m and h FfP= 1 m: Figure 1 Standard basic rack tooth profile and mating standard basic rack tooth profile Item Standard
28、 basic rack value P 20 h aP 1 m c P 0,25 m h fP 1,25 m fP 0,38 m (1) s P is the tooth thickness of standard basic rack tooth; e P is the spacewidth of standard basic rack; p is the pitch; m is the module. s p e p p 2 - ;m 2 - = (2)BSISO53:1998 BSI 05-1999 3 where For a basic rack, where P= 20 and 0,
29、295 m c P# 0,396 m: where h fPis the dedendum of the basic rack tooth. The centre of fP maxis on the centre of the rack space. NOTEThe actual root fillet, which is outside the active profile, can vary depending on influences such as the method of manufacturing, profile shift and number of teeth. 5.1
30、0 The dimensions of the standard basic rack tooth profile c P , h aP , h fPand h wPmay also be quoted as a multiple of the module m, i.e. relating to m = 1. In this case, they are identified by an asterisk, for example fP max is the maximum fillet radius of the basic rack; c P is the bottom clearanc
31、e between standard basic rack tooth and mating standard basic rack tooth; P is the pressure angle. (3)BSISO53:1998 4 BSI 05-1999 Annex A (informative) Basic rack recommendations for various applications A.1 Application of basic rack forms Alternative basic rack tooth profiles may be used based on ap
32、plication requirements Standard basic rack tooth profile type A is recommended for gears transmitting high torques. Basic rack tooth profile types B and C are recommended for normal service. Type C may be applied for manufacturing with some standard hobs. Basic rack tooth profile type D is equivalen
33、t to a full radius form for the fillet. The enlarged dedendum, h fP= 1,4 m, with the associated fillet radii, fP= 0,39 m, permits the finishing tool to work without interference, while maintaining the maximum fillet radius. This profile is recommended for high-precision gears transmitting high torqu
34、es and consequently with tooth flanks finished by grinding or shaving. Care should be taken to avoid creating notches in the fillet during finishing, which would create stress concentrations. Characteristics of the basic rack tooth profile types are given in Table A.1. Table A.1 Basic rack tooth pro
35、files A.2 Basic rack tooth profiles with undercut A basic rack tooth profile with a chosen undercut,U FP , and angle of undercut, FP , is used for gears cut by a protuberance tool and finished by grinding or shaving, see Figure A.1. The specific values of U FPand FPdepend on influences such as the m
36、ethod of manufacturing, which are not specified in this International Standard. Symbol Types of basic rack tooth profile A B C D P 20 20 20 20 h aP 1 m 1 m 1 m 1 m c P 0,25 m 0,25 m 0,25 m 0,4 m h fP 1,25 m 1,25 m 1,25 m 1,4 m fP 0,38 m 0,3 m 0,25 m 0,39 m Figure A.1 Basic rack tooth profile with a
37、chosen undercutblankBS ISO 53:1998 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing BritishStandards. It presents the UK view on standards in Europe and at the international level. It is incorporated by Royal Chart
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