Deformation sensor

• US 7,703,333 B2
• Filed: 09/06/2007
• Issued: 04/27/2010
• Est. Priority Date: 09/15/2006
• Status: Expired due to Fees

• Current Assignee: Sumitomo Riko Company Limited.
• Original Assignee: Tokai Rubber Industries Limited
• Inventors: Saitou, Yuuki, Kato, Rentaro, Hashimoto, Kazunobu, Hayakawa, Tomonori
• Primary Examiner(s): NOORI, MAX H
• Application Number:
  US11/896,904
• Publication Number:
  US 20080066564A1
• Time in Patent Office: 964 Days
• Field of Search: 73760-860
• US Class Current: 73/849
• CPC Class Codes: G01L 1/20 by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids of piezo-resistive materials G01L1/18; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress

Abstract

A deformation sensor, which has excellent workability and a high degree of freedom in shape design and which can detect deformation and load in a wide area of components and portions, has a main body of sensor, electrodes which are connected to the main body of sensor and can output electric resistances, and a restraining component which restrains elastic deformation of at least a part of the main body of sensor. The main body of sensor has an elastomer, and spherical conductive fillers which are blended into the elastomer at a high filling rate in an approximately single-particle state, and is elastically deformable. In the main body of sensor, as an elastic deformation increases, the electric resistance increases.

Claims

1. A deformation sensor comprising:

an elastically deformable main body of the sensor comprising an elastomer and spherical conductive fillers blended into the elastomer at a high filling rate in an approximately single-particle state, and having an electric resistance that increases as an elastic deformation increases,

an electrode that is connected to the main body of the sensor and can output the electric resistance; and

a restraining component that restrains the elastic deformation of at least a portion of the main body of the sensor.

2. The deformation sensor according to claim 1, wherein the main body of the sensor is composed of an elastomer composition consisting essentially of the elastomer and the conductive fillers, and wherein

in a percolation curve which expresses a relationship between a blending amount of the conductive fillers and the electric resistance of the elastomer composition, the blending amount of the conductive fillers at a second polarity change point at which a change of the electric resistance is saturated (saturation volume fraction:

φ

s) is not less than 35 vol %.

3. The deformation sensor according to claim 1, wherein the filling rate of the conductive fillers is not less than 30 vol % to not more than 65 vol % in the case where a total volume of the main body of the sensor is 100 vol %.

4. The deformation sensor according to claim 1, wherein the conductive fillers are carbon beads.

5. The deformation sensor according to claim 1, wherein an average particle diameter of the conductive fillers is not less than 0.05 μ

m to not more than 100 μ

m.

6. The deformation sensor according to claim 1, wherein the elastomer includes at least one rubber selected from the group consisting of silicone rubber, ethylene-propylene copolymer rubber, natural rubber, styrene-butadiene copolymer rubber, acrylonitrile-butadiene copolymer rubber and acrylic rubber.

7. The deformation sensor according to claim 1, wherein the main body of the sensor is elastically bending deformable.

8. The deformation sensor according to claim 7, wherein the main body of the sensor has an input surface into which a load is input from the outside, and an anti-input surface opposite to the input surface at a back side, and

the restraining component that restrains elastic deformation on at least one of the input surface and the anti-input surface is arranged on at least one of the input surface and the anti-input surface to be restrained.

9. The deformation sensor according to claim 1, wherein the main body of the sensor has a long shape, and

the plurality of electrodes are arranged along a longitudinal direction of the main body of the sensor.

10. The deformation sensor according to claim 1, wherein the main body of the sensor has a flat-plate shape, and

at least two or more pairs of electrodes, wherein the two electrodes of each pair of electrodes are opposite to each other, and are arranged on a peripheral edge of the main body of the sensor.