Actuator

• US 20090127979A1
• Filed: 11/12/2008
• Published: 05/21/2009
• Est. Priority Date: 11/15/2007
• Status: Active Grant

• Current Assignee: Advanced Softmaterials Inc., Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Original Assignee: Advanced Softmaterials Inc., Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Inventors: Zhao, Changming, Suda, Junko, Kobayashi, Toru, Takeuchi, Hiromitsu, Ruslim, Christian
• Granted Patent: US 7,915,792 B2
• Time in Patent Office: Days
• US Class Current: 310/328
• CPC Class Codes: H10N 30/506 of cylindrical shape with stacking in radial direction, e.g. coaxial or spiral type rolls
• CPC Class Codes: H10N 30/857 Macromolecular compositions
• CPC Class Codes: Y10S 310/80 Piezoelectric polymers, e.g. PVDF

Abstract

An actuator includes a spirally rolled cylindrical sheet body. The sheet body is formed by attaching an electrode on each side of a dielectric elastomer layer. When a voltage is applied to the electrodes, the sheet body is contracted along the direction of its thickness, and expanded in directions perpendicular to its thickness. The actuator is actuated by applying a voltage to the electrodes and stopping the voltage application, so that the cylindrical sheet body is extended and contracted along the direction of the axis. The material forming the dielectric elastomer layer has a low strain region, where the value of a strain based on a stress acting on the dielectric elastomer layer varies from zero to a value that is greater than and close to zero, and a high strain region, where the value of the strain is greater than that in the low strain region. The Young'"'"'s modulus in the low strain region is less than the Young'"'"'s modulus in the high strain region.

Claims

1. An actuator having an elastic dielectric elastomer layer, an electrode being provided on each of the sides of the dielectric elastomer layer, wherein the actuator is actuated by applying a voltage to the electrode and stopping the voltage application, so that the dielectric elastomer layer is expanded and contracted,

wherein a material forming the dielectric elastomer layer has:

a low strain region, where the value of a strain based on a stress acting on the dielectric elastomer layer varies from zero to a value that is greater than and close to zero; and

a high strain region, where the value of the strain is greater than that in the low strain region, wherein the Young'"'"'s modulus in the low strain region is less than the Young'"'"'s modulus in the high strain region.

2. The actuator according to claim 1, wherein the material forming the dielectric elastomer layer is a high polymer composition with movable cross-linking points.

3. The actuator according to claim 2, wherein the high polymer composition with movable cross-linking points is polyrotaxane.