Flat actuator or sensor with internal prestress

• US 20030048040A1
• Filed: 02/21/2002
• Published: 03/13/2003
• Est. Priority Date: 09/07/2001
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Drei-S-Werk Prazisionswerkzeuge GmbH & Company
• Inventors: Dollgast, Bernhard
• Granted Patent: US 7,045,933 B2
• Time in Patent Office: Days
• US Class Current: 310/328
• CPC Class Codes: H10N 30/204 using bending displacement, e.g. unimorph, bimorph or multimorph cantilever or membrane benders

Abstract

A flat multilayered component for use as an actuator or a sensor, is described. The flat multilayered component contains a layer of electrically activatable material, a passive middle layer disposed adjacent the layer of electrically activatable material, and a further passive material layer disposed adjacent the passive middle layer. The passive middle layer has a higher coefficient of linear thermal expansion than both of the layer of electrically activatable material and the further passive middle layer.

Claims

1. A flat multilayered component for use as an actuator or sensor, the flat multilayered component comprising:

a layer of electrically activatable material;

a passive middle layer disposed adjacent said layer of electrically activatable material; and

a further passive material layer disposed adjacent said passive middle layer, said passive middle layer having a higher coefficient of linear thermal expansion than both of said layer of electrically activatable material and said further passive middle layer.

2. The component according to claim 1, wherein said further passive material layer and said passive middle layer are inactive layers forming a metallic composite element.

3. The component according to claim 1, including a layer of metal disposed on said layer of electrically activatable material.

4. The component according to claim 1, wherein said layer of electrically activatable material has a structure formed of a plurality of sub-layers.

5. The component according to claim 1, wherein said layer of electrically activatable material is formed of a piezoceramic having at least one surface and a metal layer at least partially coating said at least one surface of said piezoceramic.

6. The component according to claim 1, wherein said layer of electrically activatable material is a piezoceramic.

7. The component according to claim 2, wherein said metallic composite element is a thermal bimetallic strip.

8. A process for producing a flat multilayered component, which comprises the steps of:

providing an assembly having a layer of electrically activatable material, a passive middle layer disposed adjacent the layer of electrically activatable material, and a further passive material layer disposed adjacent the passive middle layer, the passive middle layer having a higher coefficient of linear thermal expansion than both of the layer of elecrically activatable material and the further passive middle layer;

heating the assembly between two substantially planar plates to a temperature which is higher than a softening temperature of an adhesive for joining components of the assembly;

applying pressure orthogonally to a main plane of the assembly; and

cooling the assembly to below the softening temperature under an influence of the pressure.

9. The process according to claim 8, which comprises:

providing the further passive material layer and the passive middle layer as a metallic composite element; and

selecting the temperature such that the metallic composite element is plastically deformed by an internal stress which is produced.