Pressure sensor utilizing extension type conductive rubber

• US 5,045,829 A
• Filed: 03/02/1990
• Issued: 09/03/1991
• Est. Priority Date: 02/23/1990
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Fine Rubber Kenkyuusho
• Original Assignee: Kabushiki Kaisha Fine Rubber Kenkyuusho
• Inventors: Okuda, Yasuo, Kuramochi, Hiroshi, Ogihara, Sigeyosi
• Primary Examiner(s): Lateef, Marvin M.
• Application Number:
  US07/487,133
• Time in Patent Office: 550 Days
• Field of Search: 338/36, 338/42, 338/47, 338/4, 338/6, 73/862.65, 73/862.62, 73/862.04, 73/706, 73/718, 73/724, 73/726, 73/727, 73/754, 73/725
• US Class Current: 338/136
• CPC Class Codes: G01L 9/0058 of pressure sensitive conductive solid or liquid material, e.g. carbon granules

Abstract

A pressure sensor that utilizes an extension type conductive elastomer that will exhibit a decrease in its electrical resistance in response to an extension thereto. Like sheets of the conductive elastomer and an electrically insulative elastomer are overlaid and sandwiched between supporting members within a housing of the pressure sensor. The housing and each supporting member are preferably cylindrical or ring shaped, and which conductive elastomer has a pair of spaced electrodes electrically connected thereto at opposite points on its periphery. The periphery of the electrically insulative elastomer is squeezed continuously in a circle between the supporting members, while that of the conductive elastomer that includes recesses is squeezed therebetween discontinuously in the sections between the electrodes. When a pressure is applied to the contacting elastomers, they will be convexly deformed away from the pressure both experiencing an extension or stretching in the portions thereof that are not squeezed together. Thereby, the electrical resistance across the conductive elastomer as measured across the electrodes, will decrease in an analog fashion in response to the applied pressure. Accordingly, the applied pressure can be directly sensed as a change in electrical resistance as measured across the electrodes.

Claims

1. A pressure sensor comprising:

a housing;

a sheet of an electrically insulative elastomer;

a like-shaped sheet of an extension type conductive elastomer overlaying said electrically insulative elastomer and having a plurality of spaced radial recesses formed around the periphery thereof, which extension type conductive elastomer, when extended, exhibits a decrease in its electrical resistance value in response to the magnitude of an applied extension;

first and second spaced electrodes that are each electrically connected to said extension type conductive elastomer at the periphery thereof; and

first and second support means, each of which are cylindrical or ring shape and are made of an electrically insulative material for mounting in said housing to sandwich said overlaying extension type conductive elastomer and said electrically insulative elastomer around their periphery, with said electrically insulative elastomer squeezed therebetween continuously around the periphery thereof and with said extension type conductive rubber squeezed therebetween discontinuously around the periphery thereof in the sections between the electrodes.

2. A pressure sensor as set forth in claim 1, further including sandwiching the extension type conductive elastomer between first and second said electrically insulative elastomers.

3. A pressure sensor as set forth in claim 1, wherein the extension type conductive elastomer is an extension type conductive rubber.

4. A pressure sensor as set forth in claim 1, wherein the electrically insulative elastomer is an electric insulating rubber.

5. A pressure sensor as set forth in claim 1, wherein the electric insulation elastomer has a round shape.

6. A pressure sensor as set forth in claim 1, wherein the extension type conductive elastomer has a round shape.

7. A pressure sensor as set forth in claim 1, wherein the first and second electrodes are mounted in one or each of the first and second support member means so as to have one end of each in close engagement with the extension type conductive elastomer at spaced points on the periphery thereof.