1、DEUTSCHE NORM March 1997 I DIN Road vehicles Metric starter motor pinions Part 2: Pinions with 20“ pressure angle (IS0 9457-2 : 1994) I IS0 9457-2 ICs 43.060.1 O Descriptors: Road vehicles, internal combustion engines, starters, pinions. Straenfahrzeuge - Metrische Starterritzel - Teil 2: Ritzel mit
2、 20“ Eingriffswinkel (IS0 9457-2 : 1994) This standard incorporates International Standard IS0 9457-2 Road vehicles - Metric starter motor pinions - Part 2: Pinions with 20“ pressure angle. A comma is used as the decimal marker. National foreword This standard has been prepared by ISO/TC 22. The res
3、ponsible German body involved in its preparation was the Normenausschu Kraftfahrzeuge (Road Vehicle Engineering Standards Committee). IS0 Standard comprises 5 pages. No pari of this standard may be reproduced without the prior permission of Ref. No. DIN IS0 9457-2 : 1997-0 Y Deutsches Institut fr No
4、rmung e. V., Berlin. wth Verlag GmbH, D-10772 Berlin, has the exclusive right of sale for German Standards (DIN-Normen). English price group 06 Sales No. 0406 04.99 Page 1 IS0 9457-2 : 1994 Road vehicles Metric starter motor pinions Part 2: Pinions with 20“ pressure angle Foreword IS0 (the Internati
5、onal Organization for Standardization) is a worldwide federation of national standards bodies (IS0 member bodies). The work of preparing International Standards is normally carried out through IS0 technical committees. Each member body interested in a subject for which a technical committee has been
6、 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. IS0 collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standa
7、rdization. Draft 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 IS0 9457-2 was prepared by Technical Co
8、mmittee ISO/TC 22, Road vehicles, Subcommittee SC 15, Interchangeability of components of commercial vehicles and buses. IS0 9457 consists of the following parts, under the general title Road ve. hicles - Metric starter motor pinions: - Part 1: Currently used pinions - Part 2: Pinions with 20 degree
9、 pressure angle Annex A of this part of IS0 9457 is for information only. Page 2 IS0 9457-2 : 1994 Module Number of teeth, z 1 Scope This part of IS0 9457 specifies Pressure angle he metric modules, number of teeth and 0th 8 1) 9 10 m 2,25 23 3.0 4,O X X X X X X X X - - - X r tooth char Ci 11 12 13
10、15 X X X X X X X X X - - - - - 20“ - - cteristics whi h re necessary to ensure interchangeability of starter motor pinions with a pressure angle of 20“, used on starter mo- tors for reciprocating internal combustion engines for road vehicles. 2 Specified starter pinions Table 1 shows the specified c
11、ombinations between the metric modules and the number of teeth. 7- I 1) Care shall be taken regarding the contact ratio and hence the noise that eight-tooth pinions can generate. 3 Dimensions Detailed tooth dimensions and the inspection value W, (base tangent length) of the starter motor pinions spe
12、cified in table 1 are given in table3. The tooth dimensions specified in table3 are calculated by using the values for the tooth proportions ha/m given in table 2, h/m of 1,167 and a maximum tool radius of etp. expressed in millimetres, of 0.3m. If necessary, a radius may be inserted between da, ,“
13、and da. NOTE 1 The symbols used, which are in accordance with IS0 701zl, are illustrated in figure 1 Page 3 IS0 9457-2 : 1994 4 Other dimensions and specifications Should a chamfer be required on the pinion teeth, this shall be on the opposite face to the driving side. Dimensions and requirements no
14、t given in this part of IS0 9457 are left to the manufacturers choice. 5 Contact ratio The contact ratio should not be less than 1,05 with minimum active tip diameter, da, min, on both ring gear and pinion, and maximum design centre distance. 8 0,85 - - Module m 9 10 11 12 13 15 - - - - - 0,90 0.90
15、0.95 0.95 0.95 0.95 - - 1 ,o0 1 ,o0 - 1 ,o0 1 ,o0 1 ,o0 2.25 2,5 3.0 40 Table 2 - Tooth proportions Number of teeth, z 1 Figure 1 Page 4 IS0 9457-2 : 1994 m. O Table 3 - Tooth dimensions and Dinion insDection values Dimensions in rnillirnetres 9 7 r- - % cn 2 Lo m m 2 m m 4 - m a- c N * W N - t I Page 5 IS0 9457-2 : 1994 Annex A (inform at ive) Bibliography I IS0 286-2:1988, IS0 system of limits and fits - Part 2: Tables of standard tolerance grades and limit devi- ations for holes and shafts. 2 IS0 701 :I 976, International gear notation - Symbols for geometrical data.
