SENSORS AND ACTUATORS

Tube Actuators

Overview
Piezoelectric tube actuators are monolithic ceramics and offer flexibility in operation under such conditions as high vacuum and high temperatures. These elements are used in applications such as scanning tunneling microscopes (STM), atomic force microscopes (AFM), optical fiber modulators, fluid pumps, electrical clamps and ink jet printing, to mention a few.

When a voltage is applied to the ceramic, the length of the tube as well as the diameter contract or expand depending on voltage polarity. Three axes motion can be achieved through multi-electrode configurations, similar to bending mode actuators, using expansion and contraction of opposing sides.

Features

  • X-Y-Z Positioning
  • Solid State
  • Excellent Stability
  • Nanometer Resolution
  • Fast Response
  • Wide Range of Products
  • Custom products and electrode configurations

 

Applications

  • Scanning Microscopy (STM, AFM)
  • Optical Fiber Stretchers and modulators
  • Micropositioners
  • Fluid Pumps
  • Inkjet Printing
  • Deformable Mirrors
  • High Vacuum Operation

Stack Actuators

 

Design Equations
The equations given below may be used to estimate the displacement of piezoelectric tubes that are poled in the radial direction and have metal contacts on the inside and outside curved surfaces. Tubes are normally poled with the inside surface positive. By convention, V is positive when the applied field is with the original poling direction. However for bending deflection in segmented tubes, one segment is biased with the original poling direction while the opposing segment is biased opposite the original poling direction.

 

  • L = Tube Length
  • W= Wall thickness of the tube
  • ID = Inner Diameter
  • OD = Outer Diameter
  • V = Applied voltage
  • d31 = Piezoelectric charge coefficient
  • d33 = Piezoelectric charge coefficient
  • ΔX = Bending mode deflection
    •

    Axial motion

    ΔL = d31 . L . (V/t)

    Mean diameter change

    Δdm = d31 .dm. (V/t)

    dm=(OD+ID)/2

    X-Y Flex motion using multi-electrode configuration.

    ΔX=1.8·d31·V·L²/[ID·(OD-ID)]

     

     

    Standard Tube Actuators

    The table below shows standard tube actuators having one inch length and option 1 metallization. Actuators with shorter length are available. Displacement decreases in proportion to length. Actuators with custom inner and outer diameter are also available upon request.

    Part No. Length Outer Diameter Inner Diameter d31
      mm (in) mm (in) mm (in) pC/N
    BM527  
    500 0160 0120 1000 25.4 (1) 4.1 (0.160) 3.0 (0.120) -215
    500 0260 0210 1000 25.4 (1) 6.6 (0.260) 5.3 (0.210) -215
    BM532  
    527 0160 0120 1000 25.4 (1) 4.1 (0.160) 3.0 (0.120) -270
    527 0260 0210 1000 25.4 (1) 6.6 (0.260) 5.3 (0.210) -270

    Sensor also manufacturers actuators to your custom specifications, please contact our technical support for assistance.