2/19/2024 0 Comments Piezo electric actuator![]() In addition, the bimorph type can obtain a large displacement at a low voltage, but since it uses the displacement in the bending direction, a large generated force cannot be obtained, and there is a problem in the durability of repeated driving. The stacked type has a short electrode spacing and uses displacement in the polarization direction, so displacement can be obtained with a low voltage, but there is the inconvenience of having to stack each piezoelectric ceramic. The transverse effect type can reduce the voltage because the electrode spacing can be shorter than the longitudinal effect type, but the displacement amount is smaller because the displacement in the direction perpendicular to the polarization direction is used. The longitudinal effect type requires a large voltage to obtain displacement because the electrode spacing is long. Construction types of piezoelectric actuator Figure 2 compares longitudinal, transverse, and stacked longitudinal elements, showing the direction of displacement, and a bimorph transverse element that produces a bending displacement. Various types of actuators can be constructed to produce different types of movement by applying a voltage in a longitudinal or transverse direction to cause displacement. ![]() ![]() Piezoelectric actuator types and construction On the other hand, leveraging the inverse piezoelectric effect to manipulate the crystal dimensions enables actuators such as precision industrial positioning stages, valves, camera-lens motors for zoom and auto-focus, ultrasonic sources, and loudspeakers to be created. Its direct piezoelectric properties are exploited in devices such as sensors for pressure, vibration, acceleration, and shock, ultrasonic receivers and diagnostic equipment, sonar instruments, fish finders, non-destructive testing equipment, and microphones. A residual polarization persists after this field is removed, giving the ceramic its piezoelectric properties.Īmong these synthetic materials, PZT, or lead zirconate titanate (Pb (Zr, Ti) O 3), has high sensitivity and a high operating temperature that enable use in practical applications. A strong electric field is then applied to polarize the dipoles. After sintering, the dipoles within the crystalline structure are randomly oriented. These typically have a much higher piezoelectric constant than natural materials. Since the Curies’ research, various synthetic piezoelectric materials, or ferroelectric ceramics, have been developed. Direct and inverse piezoelectric effects. There is also an inverse effect: applying an electric field to a material with piezoelectric properties causes a physical distortion (figure 1b), resulting in a displacement of a few microns.įigure 1a and 1b. The Curie brothers demonstrated the direct piezoelectric effect at the end of the 19 th century, showing how applying stress to naturally occurring crystalline materials such as quartz produces an electric charge (figure 1a). They offer advantages such as greater reliability, lower power consumption, smaller size, and increased positional resolution. Piezoelectric actuators that exploit the inverse piezoelectric effect to produce a displacement in response to an applied voltage can offer an alternative to familiar electromagnetic devices such as motors and solenoids. By Patrik Kalbermatten, Senior Manager – Distribution Promotion Product Management Magnetic, Sensor & Actuator at KEMET Electronics Corporation a YAGEO company
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