Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Piezohydraulic Actuator: A Powerful Midget

09.10.2014

Researchers at Siemens have developed a small but powerful piezo­hydraulic actuator. Although it is only about nine centimeters long, it can apply a force of more than 150 newtons - equivalent to a weight of 15 kilograms. Such actuators are used to operate valves and flaps, for example, and can also be employed in robots.

The concept combines piezomechanics with hydraulics. A voltage causes tiny deflections in a piezoelectric crystal and an internal hydraulic system combines these small movements to generate a rise of two centimeters. Purely electromagnetic actuators loose efficiency if they are very small.

Another advantage of the new actuator is its metallic enclosure, which ensures that all of the required hydraulic fluid is contained in the system so that the actuator only has to be supplied with electricity and not with fluid. Moreover, the actuator is protected against external influences such as dust, humidity, and chemicals.

Piezoelectric crystals expand in a particular direction as soon as a voltage is applied. These crystals are used to drive injection valves in combustion engines, for example. One of their advantages is their dynamic response. Due to their great stiffness, they respond with almost no lag. By contrast, a conventional hydraulic system needs to have a central pump compress the hydraulic fluid in all of the system's pipes before it can generate a mechanical motion.

The piezohydraulic actuator developed by Siemens' global research department Corporate Technology (CT) achieves a high level of stiffness because it only needs six milliliters of hydraulic fluid. The enclosed hydraulic system consists of three adjacent metallic bellows that can expand along an axis and are connected to one another by non-return valves. If the piezoelectric crystal is excited, it expands into the central chamber, where it creates pressure.

This pressure opens the valve to the adjacent chamber, which has an actuator stem attached to its front. The inflowing fluid slightly expands the bellows and the actuator stem is extended. Using a patented integration solution, the developers achieve a total rise of two centimeters:

They operate the piezoelectric crystal with a high-frequency sawtooth voltage and combine the rapid succession of small expansions to create a completely smooth motion of the actuator stem. The concept has two advantages:

If the reverse voltage waveform is applied, the pumping direction and the motion are reversed as well. In addition, the actuator maintains its extension once it has been set. By contrast, the actuators used in conventional gears to transmit power cannot withstand vibrations and other influences over the long-run.

The system is a further development of a piezohydraulic actuator that CT created for controlling the valves of large-scale combustion engines such as gas turbines. According to the developers, the new actuator might also be used for other applications such as in robots, in the operation of aircraft ailerons, and in medical and cleanroom technology.

Weitere Informationen:

http://www.siemens.com/innovationnews

Dr. Norbert Aschenbrenner | Siemens InnovationNews

More articles from Machine Engineering:

nachricht Making lightweight construction suitable for series production
24.04.2017 | Laser Zentrum Hannover e.V.

nachricht It Takes Two: Structuring Metal Surfaces Efficiently with Lasers
15.03.2017 | Fraunhofer-Institut für Lasertechnik ILT

All articles from Machine Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

NASA's Fermi catches gamma-ray flashes from tropical storms

25.04.2017 | Physics and Astronomy

Researchers invent process to make sustainable rubber, plastics

25.04.2017 | Materials Sciences

Transfecting cells gently – the LZH presents a GNOME prototype at the Labvolution 2017

25.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>