Synchronous drives can be divided into 3 categories:īelt drives are particularly useful in applications where layout flexibility is important. SDP/SI supplies hobbyists, students, distributors and a wide variety of OEMs with high-quality machined timing belt pulleys, molded pulleys, timing belts, sprockets, and chains at affordable prices. However, chain drives are often used where positive synchronization between shafts and transmission of substantial torque is required. The positive nature of these drives makes them capable of transmitting large torques and withstand large accelerations. Due to this design, they do not slip and there is no relative motion between the two elements in mesh. Synchronous drives employ the positive engagement of two sets of meshing teeth. In measuring the length of a belt, the belt should be rotated at least two revolutions of the belt in order to (a) seat the belt properly in the pulley grooves, (b) divide equally the total force between the two strands of the belt, and (c) determine the midpoint of the center distance travel of the movable pulley which shall define the center distance.More Videos Helpful Videos Download Timing Belt Infographic Measuring forces for the standard belt sections and widths are shown in Table 13. Any pair of equal diameter pulleys of the proper pitch and manufactured to the specifications shown in the “Synchronous Belt Pulleys” section may be used for measuring provided the clearance between the theoretical belt tooth width and the groove width of the measuring pulley is not less than the minimum values shown in Table 12. The fixture is shown schematically in Figure 9. Recommended measuring pulley dimensions are shown in Table 12. One of the two pulleys is fixed in position while the other is movable along a graduated scale. The pitch length of a belt shall be determined by placing the belt on a measuring fixture comprising two pulleys of equal diameter, a method of applying force and a means of measuring the center distance between the two pulleys. WIDTH TOLERANCE.īelt width tolerances for all belt sections are given in Table 11. For fixed center drives consult the belt manufacturer.
The belt length tolerances shown in Table 10 apply to all belt sections and represent the total manufacturing tolerance on the belt length. Standard belt widths and width designations are shown in Table 11. Standard belt pitch lengths, belt length designations and numbers of teeth are shown in Table 10. The tooth dimensions for double-sided belts are identical to those of a single-sided belt. Table 9 and Figure 7 show the nominal tooth dimensions for each of the standard belt sections.
Table 8 gives the Standard B NOMINAL TOOTH DIMENSIONS. STANDARD SECTIONS.īelt sections are specified in terms of “pitch”.
The nomenclature for double-sided belts will be the same as for single-sided belts with the addition of the prefix “D” in front of the belt section – Example 300DL075. For example, an L section belt 30.000 inches in pitch length and 0.75 inches in width would be specified as a 300L075 Synchronous Belt. The digits following the belt section designation represent the nominal belt width times 100. The first digits specify the belt length to one-tenth inch followed by the belt section (pitch) designation. Synchronous Belt sizes are identified by a standard number.