Elliptec piezoelectric motors, actuators and resonators

Piezoelectric elements are based on laminated ceramics that expand by a few microns when an electric microvoltage is applied. The rate of expansion is entirely predictable and completely silent. Unimatic's new Elliptec products exploit these characteristics to create useful high-precision motion. The design is such that the units are inexpensive to produce and can therefore be used in a huge range of applications, particularly those requiring precise control, low weight or small size, portability, or minimal energy consumption.

The actuators are the simplest of the Elliptec range, using the deformation directly or through a lever arm to increase the stroke length. This gives a two-position (extended and retracted) operation; multi-position actuators are also available, but are more complicated in design.

To create continuous motion, the motors repeatedly cycle the piezo element; both linear and rotary version are available. In use, precision is achieved because the number of cycles is defined as a count, against a time base, or in conjunction with a feedback signal.

Resonators are designed to vibrate when excited by a piezoelectric element and typically are customised products produced to specific customer requirements.

Benefits of Elliptec products

The Elliptec products are said to be silent, lightweight, ultra-compact, silent, versatile, precise and low cost, so Unimatic is expecting to apply them in a diverse range of applications. Unimatic is already looking at their use in CD trays and auto-focus cameras, medical applications and precision optics. Exploratory discussions are underway for a number of automotive applications, including within the fuel supply systems, passenger features and low-emissions developments.

Unimatic's Managing Director, Martin Stevens, says: "Applications are nearly all bespoke and we can offer high-level support for users of piezo actuation. Alternatively, we have made available a starter pack that includes everything needed to install a unit. This lets potential users to both 'plug and play' to explore the potential of the technology and to undertake their own installations with confidence.

"The use of piezo is now growing rapidly, as engineers come to appreciate how it addresses today's needs for low cost, light weight, high precision and total reliability."