Development of the Center-Less Gear Lapping Machine and the Lapped Gears

Abstract

The objective of this present study is to develop a center-less gear lapping machine that can simultaneously smooth all of tooth flanks of a steel gear to a maximum peak-valley height ( Rz ) of less than 1 µm in a short time without fixing the gear to a shaft. A work gear meshes with two lap gears as crossed helical gears and is supported by a guide gear during the lapping. The two lap gears and the guide gear are nylon gears. Lapping slurry which contains abrasive grains is supplied to the meshing teeth. The present paper presents the mechanism of the center-less lapping process and the structure of the lapping machine designed and manufactured by the present authors. The behavior and amount of removed mass of the work gear are investigated during the lapping process. In addition, the work gears lapped using the proposed machine are evaluated with respect to the tooth roughness and the accuracy of the tooth profile, tooth trace, and pitch. Nylon lap gears are also tested to investigate their lives.

Keywords

• gear
• lapping
• center-less
• abrasive grain
• nylon gear
• surface roughness
• tooth profile