PIEZOELECTRIC MICRO-BLOWER

• US 20090232683A1
• Filed: 05/27/2009
• Published: 09/17/2009
• Est. Priority Date: 12/09/2006
• Status: Active Grant

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: HIRATA, ATSUHIKO, Wada, Hiroaki, Kamitani, Gaku, Kanai, Shungo, Sunaga, Midori
• Granted Patent: US 8,678,787 B2
• Time in Patent Office: Days
• US Class Current: 417/413.200
• CPC Class Codes: F04B 43/046 with piezoelectric drive
• CPC Class Codes: F04B 45/047 Pumps having electric drive
• CPC Class Codes: F04B 53/1077 Flow resistance valves, e.g. without moving parts

Abstract

A piezoelectric micro-blower capable of efficiently conveying compressive fluid without use of a check valve and ensuring a sufficient flow rate. The micro-blower has a blower body with a first wall and a second wall. Openings are formed in the respective walls and face a center of a diaphragm. An inflow path allowing the openings to communicate with the outside is formed between the walls. By applying a voltage to a piezoelectric element to cause the diaphragm to vibrate, a part of the first wall close to the first opening vibrates. Thus, gas can be drawn from the inflow path and discharged from the opening in the second wall.

Claims

1. A piezoelectric micro-blower comprising:

a blower body;

a diaphragm secured to the blower body at a perimeter thereof and having a piezoelectric element;

a first wall attached to the blower body and positioned so as to define a blower chamber between the diaphragm and the first wall, the first wall including a first opening facing a center of the diaphragm, the first opening in fluid communication with the blower chamber;

a second wall spaced from the first wall and disposed opposite the blower chamber with the first wall interposed between the second wall and the blower chamber, the second wall including a second opening facing the first opening; and

an inflow path formed between the first wall and the second wall, the inflow path having outer ends communicating with the outside of the piezoelectric micro-blower, and having inner ends connected to the first opening and the second opening.

2. The piezoelectric micro-blower according to claim 1, wherein a center space having an opening area greater than those of the first opening and the second opening is formed at the inner ends of the inflow path, the inner ends being connected to the first opening and the second opening.

3. The piezoelectric micro-blower according to claim 2, wherein the inflow path includes a plurality of paths extending radially from the center space, each path having an outer end provided with an inlet.

4. The piezoelectric micro-blower according to claim 3, wherein the outer end of each path opens on a different surface of the piezoelectric micro-blower than the second opening.

5. The piezoelectric micro-blower according to claim 2, wherein the opening area of the center space is dimensioned such that a part of the first wall facing the center space resonates in response to displacement of the diaphragm.

6. The piezoelectric micro-blower according to claim 5, wherein the part of the first wall facing the center space vibrates with a phase delay of about 90°

relative to vibration of the diaphragm.

7. The piezoelectric micro-blower according to claim 1, wherein the piezoelectric element is an annular piezoelectric element having a hollow at a center thereof.

8. The piezoelectric micro-blower according to claim 1, wherein the diaphragm including the piezoelectric element is configured so as to be displaced in a first-order resonance mode or a third-order resonance mode when a voltage is applied to the piezoelectric element.

9. The piezoelectric micro-blower according to claim 1, wherein the blower body includes:

a top plate defining the second wall;

a flow path plate;

a separator defining the first wall;

a blower frame; and

a bottom plate.

10. The piezoelectric micro-blower according to claim 9, wherein the diaphragm is secured between the blower frame and the bottom plate.

11. The piezoelectric micro-blower according to claim 9, wherein the flow path plate defines a center space, and the separator, the blower frame, the bottom plate and the diaphragm include notches at respective diagonal corners that form inlets to the center space.

12. The piezoelectric micro-blower according to claim 11, wherein the bottom plate includes a slit.

13. The piezoelectric micro-blower according to claim 1, further comprising an intermediate plate interposed between the diaphragm and the piezoelectric element.