A review of methods for determining contact stress in polymer base gears
Subject Areas :
1 -
Keywords:
Abstract :
Basically, gears are an evolved form of friction wheels that have teeth added to them to prevent slippage and ensure relative motion uniformity. The use of polymer gears is increasing due to advantages such as corrosion resistance, injection molding capability, operation without lubricants and low noise. However, the mechanical strength, thermal resistance and durability of polymer gears are lower than metal gears. The locking mechanism in metal gears is different from polymer gears. Among the important damages that lead to failure of polymer gears is thermal deformation, which does not exist in metal gears. In polymer gears, due to the viscoelastic and plastic nature of polymers, a lot of heat is generated during gear engagement and the temperature increases. An increase in temperature causes the ribs to soften and, as a result, change their shape. Pitting, fatigue and wear are other factors that lead to failure of polymer gears. The contact stress resulting from the torque applied to the gear plays the most important role in the intensity of each of the mentioned delays. Investigating the contact stress in polymer gears, including the challenges of industrialists and researchers, will provide a better understanding for the better design of these types of gears, as well as life expectancy. This research is a review of various methods for determining and checking contact stress, including Hertz numerical model, standard method and finite element method.
