ISO INTERNATIONAL STANDARD 21342 First edition 2019-05 Synchronous belt drives Automotive belts and pulleys Reference number ISO 21342:2019(E) Tso @IS02019 IS0 21342:2019(E) COPYRIGHTPROTECTEDDOCUMENT @ IS0 2019 All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either IsO at the address below or Iso's member body in the country of the requester. ISO copyright office CP 401 : Ch. de Blandonnet 8 CH-1214 Vernier, Geneva Phone: +41 22 749 01 11 Fax: +41 22 749 09 47 Email: [email protected] Website: www.iso.org Published in Switzerland ii @ IS0 2019 - All rights reserved IS0 21342:2019(E) Contents Page Foreword ..iv 1 Scope .1 2 Normative reference. 3 Terms and definitions 4 Profiles. 5 Belt designation ..2 6 Belt dimensions and tolerances .2 6.1 Belt tooth dimensions - Trapezoidal tooth belts of types ZA and ZB .2 6.2 Belt tooth dimensions - Curvilinear tooth belts of types ZH and YH .3 6.3 Belt tooth dimensions - Curvilinear tooth belts of types YR and ZR .4 6.4 Belt tooth dimensions - - Curvilinear tooth belts of types YS and zS. 6.5 Belt pitch length and tolerances .6 6.6 Belt widths and tolerances. .7 7 Pitch length measurement 7.1 Measuring fixture.. .7 7.2 Total measuring force 7.3 Procedure. ..8 7.4 Dimensions and clearance between measuring pulley and belt, and measuring pulley grooves.. 9 8 Lateral runout measurement ..12 8.1 Fixture. ..12 8.1.1 Belt ..12 8.1.2 Pulleys. .12 8.2 Measuring device .12 8.3 Procedure ..12 8.4 Results. ..12 9 Pulley types. ..13 10 Pulley designation .13 11 Pulley groove profile ..14 11.1 Pulleys of types ZA and ZB (involute groove profile) .14 11.2 Pulleys of types ZH and YH ..15 11.3 Pulleys of types ZR and YR .16 11.4 Pulleys of types ZS and YS. ..16 12 Pulley dimensions and tolerances ..17 12.1 Pitch tolerances ..17 12.2 Pulley outside diameter tolerances 12.3 Minimum pulley width. .18 12.4 Flange dimensions. 18 12.5 Other pulley tolerances ..19 12.5.1 Axial runout .19 12.5.2 Radial runout .20 12.5.3 Parallelism. 20 12.5.4 Taper. 20 13 Quality specification .20 @ IS0 2019 - All rights reserved ii