There are two kinds of timing belt teeth: trapezoid teeth and arc teeth.

There are two size systems for trapezoid tooth timing belt: pitch system and module system.

There are three series of arc teeth: arc teeth (H series is also called HTD belt), flat top arc teeth (s series is also called STPD belt) and concave top parabola teeth (R Series).

Excepting the curved tooth shape, the structure of the spiral tooth timing belt is basically the same as that of the trapezoid tooth timing belt, and the pitch of the belt is the same. The tooth height, root thickness and root fillet radius of the spiral tooth timing belt are larger than those of the trapezoid tooth. After the tooth is loaded, the stress distribution is good, the stress concentration of the tooth root is smoothed, and the bearing capacity of the tooth is improved. Therefore, the arc tooth timing belt transmits more power than the trapezoid tooth timing belt, and it can prevent the interference of teeth in the meshing process.

The arc tooth timing belt has the advantages of good wear resistance, low noise, no lubrication, and can be used in the harsh environment with dust. It has been widely used in food, automobile, textile, pharmaceutical, printing, papermaking and other industries.