Abstract
Plastic gears have several advantages such as light weight, reduce noise, and high degree of freedom in gear geometry, in comparison with metal gears. They are generally used without lubrication. Therefore the amount of used of plastic gears are increasing, and used for motion and power transmission. But the study for strength of plastic gears is not done. The demand to power transmission for plastic gears will become high from now on, since it has been used with emphasis on an actual result. The abrasion and damage of the tooth of plastic gears has become a problem. This paper describes the strength of Injection molded plastic helical gears. In early reports, we carried out high load, high speed gear test. But, resulting in these test gear life is below 1.0×10^7. Generally, this is inappropriateness for design life. In this study, we carried out low load, low speed gear test expect to enlarge gear life. As a result, remarkable gear life extension is confirmed.
