Although the precision of the teeth of the plastic gear is higher than that of the metal gear, the plastic gear concentricity is difficult to guarantee due to the process of injection molding. And during the plastic gear forming process, shrinkage deformation is easy to occur and must be compensated.
If the plastic gear is in a high temperature working environment, the coefficient of thermal expansion should be fully considered in the design of the gear. Otherwise, Meshing interference occurs when gears is working in a high temperature environment, and the phenomenon of low coincidence will occur in the low temperature environment.
Plastic gears have the advantages of light weight, corrosion resistance and low friction factors, but there are still some shortcomings.
1. The mechanical strength is low, and the transmission power and torque cannot be too large.
2. Poor thermal conductivity, poor creep resistance, easy deformation in high temperature environment, and low continuous operation capability of parts.
3. Shrinkage deformation occurs during molding, and accuracy is difficult to control.
The content is from < CHINA GEARS INDUSTRY YEARBOOK >