GEAR TOOTH MODIFICATION FOR NOISE REDUCTION IN AUTOMOTIVE TRANSMISSIONS

A method for gear tooth modification for an automotive transmission is introduced to reduce gear noise that is caused by the impact of gear teeth. The major causes of tooth impact are the elastic deformation of the gear teeth and shafts of the transmission under loading and the errors in the manufacturing of gears. A theoretical shape of an objective tooth profile for avoiding tooth impact is derived from the magnitudes of the elastic deformation of the gear teeth and shafts and from the overall manufacturing errors in gears. The objective tooth profile function is converted to conventional data forms that are usually communicated to commercial gear measuring and inspection instruments. The proposed method applies to the transmission for a four-wheel-drive automobile. The gear noise is reduced to a sound level of eight dB.