The tooth shape of timing belt in the automobile industry is divided into Za type and ZB type. The former is similar to L-type, while the latter is mainly used for high load engines such as diesel engines, and the tooth type is similar to H-type. Both tooth types are specified in international standards ISO 9010 and ISO 9011 and American Medical Association standards Jaso e 105 and Jaso e 106.
In order to improve the strength of the camshaft and reduce the noise, the curved tooth synchronous belt is gradually used to drive the camshaft. At present, almost all synchronous belts used in newly developed automobile engines use curved teeth. The automobile arc tooth synchronous belt has two pitches of 9.525 mm and 8 mm, which cannot be interchanged with the general industrial arc tooth synchronous belt.
