The friction rail WUFr000 is part of the friction contact of the piezoelectric ultrasonic motor WUMoLL000 (see Figure 2). Another part of the frictional contact is the friction element WUFe000 (see Figure 1).
The friction rail is mounted on a movable element of the motor (see Figure 2). The friction element is mounted on the WUAkLL000 piezoelectric ultrasonic actuator.
The friction rail may be made in the form of a strip or the form of a ring.
When the motor is running, the friction element, moving along a circular, elliptical, or inclined linear path, periodically presses against the friction rail, pushing it with a driving force.
The friction element engages with the friction rail due to the frictional force arising between the friction element and the friction rail.
In the linear portion of the load characteristic, engagement occurs without slipping. At high loads, slipping of the friction element relative to the friction surface of the rail may occur.
To avoid wear of the frictional contact of the motor, the friction rail is made of hard wear-resistant ceramic, which provides a long motor life and a high coefficient of friction with the friction surface of the friction element.