The toothing type and pitch of the synchronous belt wheel are the same as those of the synchronous belt. (For specific reference: arc tooth synchronous belt or trapezoid tooth synchronous belt) only the number of teeth (or diameter) and structure need to be determined.
The number of teeth (or diameter) of the synchronous belt wheel is generally to determine the number of teeth of the small wheel first, and then determine the number of teeth of the large wheel according to the transmission ratio.
In order to ensure the proper life of the synchronous belt, the diameter of the small synchronous belt wheel should be larger than the minimum allowable bending diameter in the table (see the minimum allowable bending diameter of the synchronous belt on the webpage for details), and then converted into the minimum number of teeth. As long as the structure and cost allow, from the consideration of the life of the timing belt, the number of teeth of the small wheel is better than the minimum number of teeth allowed. After the number of teeth of the small wheel is determined, the number of teeth of the large wheel can be determined according to the transmission ratio. Then determine the center distance of the two pulleys according to the structure, and calculate the length of the pitch line or the total number of teeth according to the pitch of the synchronous belt. At this point, the transmission parameters are all determined.
There are many types of synchronous belt pulleys, from the shape can be divided into flangeless B type (there are only BF with gears at both ends and BS without gears BS) and flanged A type , In addition to the gear teeth with baffles at both ends, there is a section of cylindrical flange (AF type with baffles and AS type without baffles).
From the perspective of the way of coupling with the shaft, it can be divided into three types: screws, keys and expansion sleeves (so-called keyless coupling). The screw connection is simple and easy to assemble and disassemble, but the shaft wheel has poor concentricity, and the corresponding flat square or socket should be machined on the shaft; the advantages and disadvantages of the key connection are self-evident; the expansion sleeve connection performance is good, but the cost is high.