Piezoelectric member

Patent metadata

Field	Value
Publication number	US-11276812-B2
Application number	US-201816209190-A
Country	US
Kind code	B2
Filing date	Dec 4, 2018
Priority date	Feb 9, 2018
Publication date	Mar 15, 2022
Grant date	Mar 15, 2022

Abstract

A piezoelectric body that is excellent in endurance, flexibility and bendability is achieved. A piezoelectric member includes: belt type first and second conductive rubber sheets that face each other; and a piezoelectric layer formed between an upper surface of the first conductive rubber sheet and a lower surface of the second conductive rubber sheet. The piezoelectric layer is made of a piezoelectric coating material with which at least either one of the upper surface of the first conductive rubber sheet and the lower surface of the second conductive rubber sheet is coated. When a pressure is applied to the piezoelectric layer through at least either one of the first conductive rubber sheet and the second conductive rubber sheet, a potential difference is generated between the first conductive rubber sheet and the second conductive rubber sheet.

First claim

What is claimed is:

1. A piezoelectric member comprising:
a belt type first conductive rubber sheet and a belt type second conductive rubber sheet having respective main surfaces that face each other; and
a piezoelectric layer formed between the main surface of the first conductive rubber sheet and the main surface of the second conductive rubber sheet,
wherein the piezoelectric layer is made of a piezoelectric coating material with which at least either one of the main surface of the first conductive rubber sheet and the main surface of the second conductive rubber sheet is coated, and,
when a pressure is applied to the piezoelectric layer through at least either one of the first conductive rubber sheet and the second conductive rubber sheet, a potential difference is generated between the first conductive rubber sheet and the second conductive rubber sheet, and
each of the first conductive rubber sheet and the second conductive rubber sheet is made of a conductive rubber formed by adding carbon particles to a mixture of thermoplastic elastomer and polypropylene so that a volume resistivity is 0.05 Ω·cm to 0.10 Ω·cm.

2. A piezoelectric member comprising:
a cable type first piezoelectric body and a cable type second piezoelectric body that are adjacent to each other,
wherein each of the cable type first piezoelectric body and the cable type second piezoelectric body includes a conductive rubber having a circular cross section, and a piezoelectric layer formed on an outer peripheral surface of the conductive rubber,
the piezoelectric layer is made of a piezoelectric coating material with which the outer peripheral surface of the conductive rubber is coated, and,
when a pressure is applied to at least either one of the piezoelectric layer of the cable type first piezoelectric body and the piezoelectric layer of the cable type second piezoelectric body, a potential difference is generated between the cable type first piezoelectric body and the cable type second piezoelectric body, and
the conductive rubber is a mixture of thermoplastic elastomer and polypropylene to which carbon particles are added so that a volume resistivity is 0.05 Ω·cm to 0.10 Ω·cm.

3. The piezoelectric member according to claim 2 ,
wherein the cable type first piezoelectric body and the cable type second piezoelectric body are arranged in parallel to each other.

4. The piezoelectric member according to claim 2 ,
wherein the cable type first piezoelectric body and the cable type second piezoelectric body are stranded together.

5. The piezoelectric member according to claim 2 , further comprising
a protective layer collectively covering the cable type first piezoelectric body and the cable type second piezoelectric body.

6. The piezoelectric member according to claim 5 , further comprising:
a first connecting wire drawn out from a first end surface of the cable type first piezoelectric body; and
a second connecting wire drawn out from a second end surface of the cable type second piezoelectric body,
wherein the first end surface of the cable type first piezoelectric body and the second end surface of the cable type second piezoelectric body are opposite to each other in a longitudinal direction of the piezoelectric member,
the first connecting wire is routed along the cable type first piezoelectric body toward a side on which the second end surface of the cable type second piezoelectric body is positioned, and
the cable type first piezoelectric body, the cable type second piezoelectric body and the first connecting wire are collectively covered by the protective layer.

7. The piezoelectric member according to claim 2 ,
wherein the cable type first piezoelectric body and the cable type second piezoelectric body are fixed to each other at one or more portions of the cable type first piezoelectric body and the cable type second piezoelectric body in a longitudinal direction.

8. The piezoelectric member according to claim 1 ,
wherein, in a cross-sectional view, widths of the first conductive rubber sheet, the second conductive rubber sheet and the piezoelectric layer are same as one another.

9. The piezoelectric member according to claim 1 ,
wherein the piezoelectric coating material is formed by adding lead zirconate titanate (PZT) ceramic powders into an epoxy resin.

10. The piezoelectric member according to claim 2 ,
wherein the piezoelectric coating material is formed by adding lead zirconate titanate (PZT) ceramic powders into an epoxy resin.

Assignees

• Hitachi Metals Ltd

Inventors

• Akimoto Katsuya
• Ikeda Yukio

Classifications

• H01L41/0477 Primary

  Electricity · mapped topic

• H01L41/087

  Electricity · mapped topic

• H01L41/1132

  Electricity · mapped topic

• H10N30/302

  Sensors · CPC title

• H10N30/877 Primary

  Conductive materials · CPC title