Profile shifting is an important technique in gear design for preventing tooth undercut, improving tooth geometry, enhancing load-carrying capacity, and satisfying the geometrical requirements of gear drives. However, the objectives, principles, and procedures for determining profile-shift coefficients differ among cylindrical gears, bevel gears, and worm gear drives.

This technical note presents a systematic procedure for determining profile-shift coefficients for these three types of gear drives. For cylindrical gears, the total profile-shift coefficient is determined based on the center distance and working pressure angle and is subsequently distributed between the pinion and gear according to geometrical, meshing, and strength requirements. For worm gear drives, the worm-wheel profile-shift coefficient is determined from the relationship between the working center distance and the geometrical center distance obtained after selecting standardized design parameters. For bevel gears, profile shifting is primarily used to improve tooth geometry, prevent undercut, and achieve an appropriate distribution of tooth strength between the pinion and gear; the procedures for determining height correction, tangential correction, and the corresponding tooth geometrical parameters are presented.

Worked examples for each type of gear drive are provided to illustrate the procedures for determining profile-shift coefficients and checking the principal geometrical parameters. This technical note is intended as a practical reference for students, lecturers, and engineers involved in machine-element and gear-drive design.