A Little Knowledge about Sync Belts

Synchronous belt is a product designed with the advantages of belt drive, chain drive and gear drive, so it has many advantages and is widely used: it is mainly used to transmit rotating force and reciprocating linear motion. The selection of synchronous belt is briefly introduced.

☆ Tooth shape of synchronous belt

Most people choose the synchronization belt by chance, and may not know the tooth shape of the synchronization belt. The synchronous belt is mainly divided into trapezoidal teeth and circular arc teeth. MISUMI's sync belt models are as follows:

(1) Trapezoidal tooth synchronization belt:

The trapezoidal tooth stress is concentrated in the root of the tooth, when the small belt wheel diameter is small, will make the trapezoidal tooth synchronization belt tooth shape deformation (the same as the chain drive, polygon effect), affect the mesh with the belt gear, easy to produce noise and vibration, which is very unfavorable for the high speed of the main drive. Therefore, the trapezoidal tooth synchronization belt is rarely used in the main transmission of CNC machine tools, especially machining centers, and is generally only used in the power transmission of the motion transmission or small power transmission with low speed.

Application: low speed, low power transmission;

Advantages: high transmission precision, cheap;

Disadvantages: the root is easy to stress concentration, so the load capacity is low; Loud noise and vibration.

(2) Arc tooth synchronous belt

The circular arc tooth synchronous belt overcomes the disadvantages of trapezoidal tooth synchronous belt, equalizes the stress and improves the meshing. Therefore, on the machining center, whether it is the main drive or the servo feed drive, when the belt transmission is needed, the circular arc tooth synchronous gear belt is always given priority.

Application: small pitch, small backlash, more suitable for positioning, high torque;

Advantages: high transmission accuracy, large transmission torque, low noise, can prevent interference during tooth meshing;

Disadvantages: Slightly higher price.

☆ Synchronous belt length calculation

Many people really do not know how to calculate the length of the synchronization belt (the length of the synchronization belt is the length of the internal core wire), the more lazy approach is to draw the actual synchronization wheel position in the three-dimensional software, the pitch circle diameter can be calculated according to the path length of the theoretical length, and then choose the adjacent standard synchronization belt. Then there is the same calculation formula for the same flat belt and V-belt:

Where: L ': approximate belt length; C: the center distance between the two axes; Dp: Pitch diameter of large pulley; dp: small pulley pitch diameter.Pitch circle diameter: commonly used S5M as an example, pitch pitch 5MM, module m = pitch distance ÷π, pitch circle diameter Dp = m× number of teeth z= pitch distance × number of teeth ÷π.Add one more: When the core wire is steel wire, avoid tightening from the back. Otherwise, the steel wire is repeatedly bent in two directions, and the life is not long.

Synchronous belt tooth profile analysis we can see some papers, more thorough. Synchronous wheel force calculation and life calculation, each supplier has a calculation example, no longer listed. Above, I hope to expand your ideas, thank you for reading!