Gear and Power Transmission

Abstract

The gear is a symbol of engineering. Dating back to 100 B.C., the Greeks already had a good understanding of the gear (Wikipedia 2002). The gears are used to transmit motion and power. There are many kinds of gears: spur gears, helical gears, bevel gears, hypoid gears, crown gears, worm gears, non-circular gears, gear racks, sun and planet gears, harmonic gears, etc. The teeth of a gear may follow different profiles, such as involute, cycloidal, spline, etc. Mechanical watch movement usually uses a spur cycloidal gear. This chapter studies the gear induced errors, including the gear tooth deformation error and gear assembly error.