One rev per week, without a gearbox

PiezoMotor, the Swedish company that invented a tiny linear motor that "walks" on piezoelectric "legs", has adapted the technology to produce rotating motion. It has assembled a small, backlash-free motor that produces slow, variable speed - down to one revolution per week, or less - without a gearbox.

The 23mm-diameter, high-torque (0.08Nm) PiezoLegs motor (shown above) has a resolution of less than one micro-radian - close to one ten-millionth of a turn. The maintenance-free motor, which is 32mm long and weighs 70g, does not draw any current when it is a holding position. Because the motor operates on a friction principle, it will not be harmed if its rotation is blocked.

Peo Sollerud, PiezoMotor`s vice-president of marketing, says that the rotating motor was developed in response to numerous requests. The motors will be produced in a standard range, which will be available in a few months` time, as well as in versions tailored to customers` requests.

PiezoMotor is also developing new versions of its linear machine.