Piezoelectric Linear Motor with Two Motional Functions of Small Displacement and Large Displacement

In precise positioning equipment such as an XY stage, the linear actuator (motor) is indispensable. In the practical application of such a linear motor, two motional functions of small displacement and large displacement are usually required. Both such functions have fundamentally been achieved by changing the input-voltage driving the linear motor, because it usually has only one motional function. However, in such a case, the utility of the motor having one motional function is not smooth in practice; therefore, if the linear motor is constructed by combining two motors with such different functions into one form so that it has two motional functions of small displacement and large displacement, it is presumed that the utility can be much improved. From the viewpoint of this engineering requirement, we have developed a new concept of a linear motor inherently having two motional functions of small displacement and large displacement. That is, we deal with, herein, a linear motor consisting of three or two multilayer piezoelectric ceramic stacks and one piezoelectric ceramic disk-type motor; concretely, two motor constructions based on this new concept are presented and their characteristics are experimentally investigated.