Novel tooth design for a tubular linear motor for machine tool axis

Permanent magnet tubular linear motors have shown potential for use as direct drives in high precision machine tools. These devices are capable of replacing the traditional ball screw, given their ability to overcome or reduce many of the fundamental mechanical properties that limit the precision performance of the ball screw. However, given the desire from industry to increase speed and acceleration, the physical size of the motor must be minimised while maintaining high force output to increase bandwidth in high precision applications. This paper presents a new optimal tooth design to reduce the frame size of a slotted tubular linear motor. Several design aspects of the optimal tooth are considered and general solutions are derived. Data from finite element analysis and from an experimental machine is presented to validate the new designs.