ISO INTERNATIONAL STANDARD 9457-2 First edition 1994-10-01 Road vehicles - Metric starter motor pinions - Part 2: Pinions with 20° pressure angle Vehicules routiers - Pignons de demarreurs a module métrique Partie 2: Pignons a angle de pression de 20° ISO Referencenumber ISO 9457-2:1994(E) Copyright International Organization for Standardizatior e with ISC Not for Resale ISO 9457-2:1994(E) Foreword 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 right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with IsO, also take part in the work. IsO coliaborates closely with the International Electrotechnical Commission (lEC) on all matters of electrotechnical standardization. Draft international Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International a vote. International Standard ISO 9457-2 was prepared by Technical Committee ISO/TC22, Roadvehicles, Subcommittee sc 15, Interchangeability of components of commercial vehicles and buses. IsO 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 pressure angle Annex A of this part of ISO 9457 is for information only. ISO1994 All rights reserved. Uniess otherwise specified, no part of this publication may be reproduced microfilm, without permission in writing from the publisher. International Organization for Standardization Case Postale 56 . CH-1211 Geneve 20 : Switzerland Printed in Switzerland ii ght Intermational Organization for Standardization Not for Resale INTERNATIONAL STANDARD ISO ISO9457-2:1994(E) Road vehicles Metric starter motor pinions - Part 2: Pinions with 20° pressure angle 1 Scope This part of IsO 9457 specifies the metric modules, number of teeth and other tooth characteristics which are tors for reciprocating internal combustion engines for road vehicles. 2 Specified starter pinions Table 1 shows the specified combinations between the metric modules and the number of teeth Table 1 --- Combinations between metric modules and number of teeth Module Number of teeth, z Pressure angle m 8 1) 6 10 11 12 13 15 α 2,25 + × - 2,5 × x x x 一 20° 3,0 × × 4,0 x + X 1) Care shall be taken regarding the contact ratio and hence the noise that eight-tooth pinions can generate. 3 Dimensions in table 1 are given in table 3. 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 gfp, expressed in millimetres, of 0,3m. If necessary, a radius may be inserted between d'a, min and da. NOTE1 The symbols used, which are in accordance with Iso 701[2], are illustrated in figure 1. 1 opyright International Organization for Standardizatior g permitted without license from IHS Not for Resale