Electroactive polymer actuator and diaphragm pump using the same

• US 6,960,864 B2
• Filed: 11/05/2002
• Issued: 11/01/2005
• Est. Priority Date: 12/25/2001
• Status: Expired due to Fees

• Current Assignee: Panasonic Electric Works Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Asahi Matsushita Electric Works Ltd. (Panasonic Holdings Corporation)
• Inventors: Urano, Youji, Kitahara, Harunori
• Primary Examiner(s): Dougherty, Thomas M.
• Application Number:
  US10/287,500
• Publication Number:
  US 20030117044A1
• Time in Patent Office: 1,092 Days
• Field of Search: 310/307, 310/324, 310/328, 310/365, 310/366, 310/367, 310/369, 347/68, 347/70, 347/71
• US Class Current: 310/307
• CPC Class Codes: F04B 43/0054 particularities of the flexible members
• CPC Class Codes: F04B 43/04 Pumps having electric drive
• CPC Class Codes: H02N 1/002 Electrostatic motors
• CPC Class Codes: H10N 30/2047 Membrane type

Abstract

An electroactive polymer actuator, which has the capability of improving response speed and operation reliability of a device utilizing an electroactive effect, comprises a laminate formed by alternately placing a plurality of ring members of an electroactive polymer material having different diameters and a plurality of ring electrodes having different diameters such that each of the ring members is positioned between inner and outer peripheral surfaces of adjacent ring electrodes, and a voltage applying unit for applying a voltage(s) between odd-numbered ring electrodes and even-numbered ring electrodes in the case of counting the ring electrodes in order from an innermost ring electrode of the laminate, to thereby cause a deformation in the laminate. This actuator is preferably used as a diaphragm drive unit of a diaphragm pump.

Claims

1. An electroactive polymer actuator comprising:

a laminate including a tubular member of an electroactive polymer material, a first electrode formed on an inner peripheral surface of said tubular member, a second electrode formed on an outer peripheral surface of said tubular member, a second tubular member of an electroactive polymer material, which is placed around said second electrode such that the outer peripheral surface of said tubular member is connected to an inner peripheral surface of said second tubular member through said second electrode, and a third electrode formed on an outer peripheral surface of said second tubular member; and

voltage applying means for applying a voltage between said first and second electrodes to cause a deformation in said laminate,

wherein said voltage applying means applies the voltage(s) between said first and second electrodes and between said second and third electrodes to cause the deformation in said laminate, and each of said tubular member and second tubular member is formed in a hollow cylinder shape having a center of its outer circle displaced from the center of its inner circle.

2. The electroactive polymer actuator as set forth in claim 1, wherein a wall thickness of said tubular member is determined to be greater than the wall thickness of said second tubular member, so that a uniform elongation in the axial direction of said tubular member and said second tubular member is obtained when said voltage applying means applies a same voltage between said first and second electrodes and between said second and third electrodes.

3. The electroactive polymer actuator as set forth in claim 1, wherein said electroactive polymer material is selected from the group consisting of silicone rubber and an acrylic material.

4. An electroactive polymer actuator comprising:

a laminate including a tubular member of an electroactive polymer material, a first electrode formed on an inner peripheral surface of said tubular member, a second electrode formed on an outer peripheral surface of said tubular member, a second tubular member of an electroactive polymer material, which is placed around said second electrode such that the outer peripheral surface of said tubular member is connected to an inner peripheral surface of said second tubular member through said second electrode, and a third electrode formed on an outer peripheral surface of said second tubular member; and

voltage applying means for applying a voltage between said first and second electrodes to cause a deformation in said laminate,

wherein said voltage applying means applies the voltage(s) between said first and second electrodes and between said second and third electrodes to cause the deformation in said laminate, said tubular member and second tubular member have a same wall thickness, and said voltage applying means applies the voltage between said first and second electrodes, which is smaller than the voltage applied between said second and third electrodes to obtain a uniform elongation in the axial direction of said tubular member and said second tubular member.

5. The electroactive polymer actuator as set forth in claim 4, wherein said tubular member and said second tubular member are of hollow cylinder shapes having different diameters, which are concentrically arranged to obtain said laminate.

6. The electroactive polymer actuator as set forth in claim 4, wherein said electroactive polymer material is selected from the group consisting of silicone rubber and an acrylic material.

7. An electroactive polymer actuator comprising:

a plurality of laminates each having a triangular prism shape, each of said laminates including a pair of electrodes and an electroactive polymer member, which are alternately placed in a direction of a vertical line extending from a vertex of a triangle that is a general surface of said triangular prism to a base of said triangle, said laminates being arranged as a whole in a polygonal pattern such that the vertex of said triangle is positioned in the vicinity of a center of said polygonal pattern, and each of said laminates is spaced from an adjacent laminate by a required distance; and

a voltage applying means for applying a voltage between said electrodes spaced from each other by said electroactive polymer material with respect to each of said laminates, to thereby cause a deformation in said laminate.

8. A diaphragm pump comprising the electroactive polymer actuator of claim 7 as a diaphragm drive means, and a thin sheet of a flexible material as a diaphragm, on a surface of which said laminates arranged in said polygonal pattern of the electroactive polymer actuator are mounted.

9. The electroactive polymer actuator as set forth in claim 7, wherein said electroactive polymer material is selected from the group consisting of silicone rubber and an acrylic material.

10. A diaphragm pump comprising:

an electroactive polymer actuator comprising a laminate including a tubular member of an electroactive polymer material, a first electrode formed on an inner peripheral surface of said tubular member, and a second electrode formed on an outer peripheral surface of said tubular member, and voltage applying means for applying a voltage between said first and second electrodes to cause a deformation in said laminate; and

a thin sheet of a flexible material as a diaphragm, on a surface of which said laminate of the electroactive polymer actuator is mounted.

11. The diaphragm pump as set forth in claim 10, wherein said electroactive polymer material is selected from the group consisting of silicone rubber and an acrylic material.

12. The diaphragm pump as set forth in claim 10, wherein said laminate further includes:

a second tubular member of an electroactive polymer material, which is placed around said second electrode such that the outer peripheral surface of said tubular member is connected to an inner peripheral surface of said second tubular member through said second electrode; and

a third electrode formed on an outer peripheral surface of said second tubular member,

wherein said voltage applying means applies the voltage(s) between said first and second electrodes and between said second and third electrodes to cause the deformation in said laminate.

13. The diaphragm pump as set forth in claim 12, wherein said tubular member and second tubular member are of hollow cylinder shapes having different diameters, which are concentrically arranged to obtain said laminate.

14. The diaphragm pump as set forth in claim 12, wherein a wall thickness of said tubular member is determined to be greater than the wall thickness of said second tubular member, so that a uniform elongation in the axial direction of said tubular member and said second tubular member is obtained when said voltage applying means applies a same voltage between said first and second electrodes and between said second and third electrodes.

15. A diaphragm pump comprising;

an electroactive polymer actuator comprising a spiral structure formed by winding a laminate including an elongated sheet of an electroactive polymer material, a pair of first and second electrode layers formed on opposite surfaces of said elongated sheet, and an insulation layer formed on one of said electrode layers, and voltage applying means for applying a voltage between said electrode layers to cause a deformation in said spiral structure; and

a thin sheet of a flexible material as a diaphragm, on a surface of which said spiral structure of the electroactive polymer actuator is mounted.

16. The diaphragm pump as set forth in claim 15, wherein said electroactive polymer material is selected from the group consisting of silicone rubber and an acrylic material.

17. A diaphragm pump comprising:

an electroactive polymer actuator comprising a laminate formed by alternately placing a plurality of ring members of an electroactive polymer material having different diameters and a plurality of ring electrodes having different diameters such that each of said ring members is positioned between inner and outer peripheral surfaces of adjacent ring electrodes, and voltage applying means for applying a voltage(s) between odd-numbered ring electrodes and even-numbered ring electrodes in the case of counting said ring electrodes in order from an innermost ring electrode of said laminate, to thereby cause a deformation in said laminate; and

a thin sheet of a flexible material as a diaphragm, on a surface of which said laminate of the electroactive polymer actuator is mounted.

18. The diaphragm pump as set forth in claim 17, wherein the number of said ring members is within a range of 3 to 10.

19. A diaphragm pump comprising:

a pair of electroactive polymer actuators, each of the electroactive polymer actuators comprising a laminate formed by alternately placing a plurality of ring members of an electroactive polymer material having different diameters and a plurality of ring electrodes having different diameters such that each of said ring members is positioned between inner and outer peripheral surfaces of adjacent ring electrodes, and voltage applying means for applying a voltage(s) between odd-numbered ring electrodes and even-numbered ring electrodes in the case of counting said ring electrodes in order from an innermost ring electrode of said laminate, to thereby cause a deformation in said laminate; and

a thin sheet of a flexible material as a diaphragm, on opposite surfaces of which laminates of the electroactive polymer actuators are mounted.

20. The diaphragm pump as set forth in claim 19, wherein the number of said ring members is within a range of 3 to 10.