ISO-6698-1989.pdf
《ISO-6698-1989.pdf》由会员分享,可在线阅读,更多相关《ISO-6698-1989.pdf(10页珍藏版)》请在三一文库上搜索。
1、INTERNATIONAL STANDARD IS0 6698 Second edition 1989-12-01 Cycles - Screw threads used to assemble freewheels on bicycle hubs Cycles - Filetages utilis this means that the pitch is in inch units (turns per inch or t.p.i.1 but all other dimensions are specified in metric units. A 1 3/8 (1,375) in x 24
2、 t.p.i screw thread of IS0 basic profile has been adopted in this International Standard. The basic pitch diameter of this thread differs by only 0,003 mm from that of the I,37 in x 24 t.p.i. B.S.C. thread, but, due to the smaller crest truncation of the IS0 profile (see figure 1) interference may o
3、ccur at the major diameter when an IS0 hub thread made towards its upper limit is assembled with a B.S.C. freewheel thread made towards its lower limit on major diameter. The possi- bility of interference occurring in this manner is considered to be unlikely in practice because of the effect of the
4、manufacturing tolerances (negative on the hub and positive on the freewheel) and the usual practice of using high-crested screwing taps. However, a practical investigation has been carried out and has confirmed that there is little possibility of any interference arising in practice. iii Copyright I
5、nternational Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/25/2007 00:21:48 MDTNo reproduction or networking permitted without license from IHS -,-,- INTERNATIONAL STANDARD IS0 8898 : 1989 (EI Cycles - Screw
6、threads used to assemble freewheels on bicycle hubs 1 Scope This International Standard specifies the thread profile and limits and tolerances for the screw threads used to assemble freewheels on bicycle hubs. It is based on a) the use of the IS0 basic thread profile given in IS0 66; b) satisfactory
7、 interchangeability with the corresponding British Standard Cycle (B.S.C.) thread; this has required the use of an inch pitch (t.p.i.1; c) the use of screw thread tolerance grades and tolerance positions given in IS0 965-l ; dj the use of gauges made to IS0 1502. 2 Normative references The following
8、 standards contain provisions which, through reference in this text, constitute provisions of 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 are encourag
9、ed to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and IS0 maintain registers of currently valid International Standards. IS0 88 : 1973, IS0 general purpose screw threads - Basic profile. IS0 965-l : 1980, IS0 generalpurpose metric
10、 screw threads - Tolerances - Part 1: Principles and basic data. IS0 1502 : 1978, IS0 general purpose metric screw threads - Gauging. 3 Basic IS0 thread profile and basic sizes 3.1 Basic profile The basic profile is that given in IS0 66 and is shown in figure 1. It is the theoretical profile associa
11、ted with the basic sizes of the major, pitch and minor diameters of the screw thread. 3.2 Basic sizes The basic major diameter, and the basic pitch and minor diameters determined from the basic profile, are given in table 1. Table 1 - Basic dimensions 4 Limits and tolerances 4.1 Fundamental deviatio
12、ns and maximum material limits The fundamental deviations are applied to the basic diameters and establish the maximum material limits. For the hub thread the fundamental (upper) deviations are negative and correspond to tolerance position “g” on the major, pitch and minor diameters. For the freewhe
13、el thread the fundamental (lower) deviations are zero and correspond to tolerance position “H” on the major, pitch and minor diameters. 4.2 Tolerance grades, tolerances and limits of size The application of tolerances to the maximum material limits, negative tolerances for the hub thread, and positi
14、ve tolerances for the freewheel thread, determines the minimum material limits of size. The tolerances and limits of size are given in tables 2 and 3 respectively for the hub and the freewheel. The tolerances are grade 6 in accordance with IS0 965-l. The fundamental deviations and tolerance zones ar
15、e shown in figure 2. 5 Designation Screw threads made to this International Standard are designated by a) the nominal diameter of the thread in inch units, Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 N
16、ot for Resale, 04/25/2007 00:21:48 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 6696 : 1989 (EI b) the pitch of the thread in t.p.i., cl the tolerance classes of the freewheel and hub thread respectively. EXAMPLE 1,376 - 24 6H/6g 6 Gauging system The gauging system i
17、s that laid down in IS0 1502 to which reference should be made for details of the thread profiles of the screw gauges and the method of gauge application. IS0 1502 gives formulae for the calculation of the gauge limits. These formulae have been used to calculate the gauge limits for the freewheel an
18、d hub in this International Standard, and these limits are given in tables 4 to 7. It should be noted that the pitch diameter limits given in tables 4 to 6 relate to the simple pitch diameter, and separate tolerances are given in IS0 1502 for the pitch and flank angles of these gauges. These toleran
19、ces are Pitch tolerance = 0,005 mm Flank angle tolerance = f O” 15 for profiles with complete flanks; = f O” 16 for profiles with truncated flanks. Table 2 - limits and tolerances for screw threads on hubs I I Minor Major diameter Pitch diameter diameter t.p.i. d 4 I I 4 mm mm mm I I I max. 1 tol. 1
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- ISO 6698 1989
链接地址:https://www.31doc.com/p-3779160.html