This application claims priority from Japanese Patent Application No. 2019-179611 filed on Sep. 30, 2019. The content of this application is incorporated herein by reference in its entirety.
The present disclosure relates to a fluid control device that utilizes pressure variation generated by vibration of a vibrating plate.
Various fluid control devices that transport fluid by using a piezoelectric material have been devised (see, for example, Japanese Patent No. 5177331 (hereinafter referred to as Patent Document 1)).
A pump device described in Patent Document 1 includes a housing having an inner space. The pump device further includes a vibrating plate, a piezoelectric element, and elastic support parts. The vibrating plate is disposed in the inner space, and the piezoelectric element is attached to the vibrating plate. The elastic support parts are connected to an outer peripheral portion of the vibrating plate and to an inner wall surface of the housing. According to this structure, the vibrating plate is held such that the vibrating plate can vibrate with respect to the housing.
The piezoelectric element is deformed due to driving vibration, and bending vibration of the vibrating plate is generated by the deformation of the piezoelectric element. The pressure in the inner space varies in response to the bending vibration, so that fluid is transported in one direction.
However, according to the pump device (fluid control device) of the related art described in Patent Document 1, part of the vibration of the vibrating plate may have adverse influence on the pressure distribution in a pump chamber (see
Therefore, it is difficult to improve the flow rate characteristics of the pump device according to the related art.
The present disclosure provides a fluid control device with improved flow rate characteristics.
According to embodiments of the present disclosure, a fluid control device includes a first main plate, a second main plate, a side wall member, a driving body, a first frame, first connecting portions, second apertures, a second frame, a pump chamber, and a second connecting portion. The first main plate has a first principal surface and a second principal surface. The second main plate has a third principal surface, a fourth principal surface, and a first aperture that connects a space adjacent to the third principal surface and a space adjacent to the fourth principal surface to each other. The second main plate is disposed such that the third principal surface faces the first principal surface. The side wall member is substantially annular and connected to an outer edge of the third principal surface of the second main plate. The driving body is provided on the first main plate and configured to vibrate the first main plate. The first frame is disposed outside an outer peripheral end of the first main plate. The first connecting portions connect the first main plate and the first frame to each other. Each of the second apertures is formed between adjacent ones of the first connecting portions and connects a space adjacent to the first principal surface and a space adjacent to the second principal surface to each other. The second frame is disposed outside an outer peripheral end of the first frame. The pump chamber is formed by connecting the second main plate and the second frame to each other with the side wall member. The pump chamber communicates with the first aperture and the second apertures. The second connecting portion connects the first frame and the second frame to each other.
According to the above-described structure, the outer end of the vibration of the first main plate is at the outer peripheral end of the first frame, and the second apertures are disposed inside the first frame. Accordingly, the vibration of the first main plate has a node at substantially the same position as the position of the second apertures. Thus, the shape of the vibration of the first main plate substantially coincides with the shape of the pressure distribution in the pump chamber between the first main plate and the second main plate. Therefore, adverse influence of the vibration on the pressure variation can be reduced.
According to the present disclosure, the flow rate characteristics can be improved.
Other features, elements, characteristics and advantages of the present disclosure will become more apparent from the following detailed description of embodiments of the present disclosure with reference to the attached drawings.
A fluid control device according to a first embodiment of the present disclosure will now be described with reference to the drawings.
Structure of Fluid Control Device 10
As illustrated in
As illustrated in
The first frame 21, which is a flat plate, is substantially annular and has a substantially circular outer periphery in plan view. The first frame 21 is disposed outside the outer peripheral end of the first main plate 20.
The first connecting portions 23 are disposed between the first main plate 20 and the first frame 21. The first connecting portions 23 are arranged with gaps therebetween along a circle centered on the central point of the first main plate 20. The first connecting portions 23 are connected to the outer peripheral end of the first main plate 20 and the inner peripheral end of the first frame 21.
The second frame 22 is a flat plate that is substantially annular in plan view. The second frame 22 is disposed outside the outer peripheral end of the first frame 21.
The second connecting portions 24 are substantially beam shaped. The second connecting portions 24 are disposed between the first frame 21 and the second frame 22. The second connecting portions 24 are connected to the outer peripheral end of the first frame 21 and the inner peripheral end of the second frame 22. Plural second connecting portions 24 are provided. The second connecting portions 24 are arranged with gaps therebetween along the outer periphery of the first frame 21. The number of second connecting portions 24 may be any number of 3 or more, and the second connecting portions 24 may be arranged at equal intervals along the outer periphery. In the region between the first frame 21 and the second frame 22, spaces where the second connecting portions 24 are not provided serve as apertures 240.
The first connecting portions 23 have a plurality of apertures 230 therebetween. The apertures 230 correspond to “second apertures” according to the present disclosure. The apertures 230 connect a space adjacent to the first principal surface 201 and a space adjacent to the second principal surface 202 to each other between the first connecting portions 23. The apertures 230 are through holes that are substantially circular in plan view, that is, substantially cylindrical through holes. The apertures 230 are arranged along a circle at the outer periphery of the first main plate 20. Each of apertures 230 is formed between adjacent ones of the first connecting portions 23. The apertures 230 can be arranged at equal intervals.
The shape and number of the beams and the number of the apertures 230 in the above-described structure are appropriately set so that the modulus of elasticity of the second connecting portions 24 is lower than the modulus of elasticity of the first connecting portions 23. In other words, the beams of the second connecting portions 24 are easily deformed, and the first connecting portions 23 are not easily deformed.
According to the above-described structure, the first main plate 20, the first connecting portions 23, and the first frame 21 form a flat plate portion (vibrating portion), which is held by the second connecting portions 24 such that the flat plate portion (vibrating portion) can vibrate with respect to the second frame 22.
The first main plate 20, the first frame 21, the second frame 22, the first connecting portions 23, and the second connecting portions 24 may be formed integrally with each other. Conversely, it is optional that these elements be formed integrally with each other. The portion including the first main plate 20, the first frame 21, the second frame 22, the first connecting portions 23, and the second connecting portions 24 can be easily formed when these elements are formed integrally with each other.
The piezoelectric element 30 includes a substantially circular piezoelectric plate and driving electrodes. The driving electrodes are formed on both principal surfaces of the substantially circular piezoelectric plate.
The piezoelectric element 30 is disposed on the second principal surface 202 of the first main plate 20. The center of the piezoelectric element 30 substantially coincides with the center of the first main plate 20 in plan view. The piezoelectric element 30 is deformed when a driving signal is applied to the driving electrodes. As described above, this deformation causes vibration of the flat plate portion (vibrating portion) formed of the first main plate 20, the first connecting portions 23, and the first frame 21.
The second main plate 40 is a flat plate that is substantially circular in plan view. The material, thickness, etc., of the second main plate 40 can be such that bending vibration of the second main plate 40 hardly occurs. The outer shape of the second main plate 40 is large enough to cover the outer shape of the portion including the first main plate 20, the first frame 21, the second frame 22, the first connecting portions 23, and the second connecting portions 24. The second main plate 40 has a substantially circular third principal surface 401 and a substantially circular fourth principal surface 402. The third principal surface 401 and the fourth principal surface 402 are opposite to each other.
The second main plate 40 also has an aperture 400. The aperture 400 corresponds to a “first aperture” according to the present disclosure. The aperture 400 is a substantially cylindrical through hole that extends between the third principal surface 401 and the fourth principal surface 402 of the second main plate 40. The aperture 400 is positioned to overlap the center of the second main plate 40.
The second main plate 40 is disposed such that the principal surfaces of the second main plate 40 and the first main plate 20 are parallel to each other. In this state, the third principal surface 401 of the second main plate 40 and the first principal surface 201 of the first main plate 20 face each other. The center of the second main plate 40 in plan view substantially coincides with the center of the first main plate 20 in plan view.
The side wall member 50 is a substantially annular column. The substantially annular column of the side wall member 50 can be a circler ring-shape, oval ring-shape, elliptical ring-shape, square ring-shape, rectangular ring-shape polygonal ring-shape. The material, thickness, etc., of the side wall member 50 can be such that bending vibration of the side wall member 50 hardly occurs. The side wall member 50 may be formed either separately from or integrally with the second frame 22 or the second main plate 40.
The side wall member 50 is disposed between the second frame 22 and the second main plate 40. One end of the side wall member 50 in the height direction is connected to a surface of the second frame 22 adjacent to the first principal surface 201. The other end of the side wall member 50 in the height direction is connected to the third principal surface 401 of the second main plate 40.
According to the above-described structure, the fluid control device 10 has a space surrounded by the second main plate 40, the side wall member 50, and the flat plate formed of the first main plate 20, the first frame 21, the second frame 22, the first connecting portions 23, and the second connecting portions 24. This space serves as a pump chamber 100 of the fluid control device 10. The pump chamber 100 communicates with the first aperture 400 and the second apertures 230. In other words, the pump chamber 100 communicates with a space outside the fluid control device 10 through the first aperture 400 and the second apertures 230. Although the pump chamber 100 also communicates with the outside space through the apertures 240, it is not necessary that the pump chamber 100 communicate with the outside space through the apertures 240.
The fluid control device 10 having the above-described structure transports fluid based on the principle described below.
When a driving signal (driving voltage) of a predetermined frequency is applied to the piezoelectric element 30 of the fluid control device 10 according to the present embodiment, the piezoelectric element 30 is deformed at a predetermined frequency, as illustrated in
As illustrated in
The fluid control device 10 is structured such that the center of the vibrating portion serves as an antinode of the vibration and that two vibration nodes ND1 and ND2 are arranged in a direction toward the outer periphery of the vibrating portion. The outer peripheral end of the vibrating portion is held by the second connecting portions 24 such that the outer peripheral end can vibrate, and therefore serves as a free end. Accordingly, as illustrated in
As described above, the pressure variation in the pump chamber 100 has a node at the position of the apertures 230 (position of the first connecting portions 23), and nodes in the pump chamber 100 including the above-mentioned node are determined by the order of the vibration. Accordingly, as illustrated in
The fluid control device 10 is structured such that the apertures 230 communicate with the outside of the fluid control device 10. Therefore, the position of the node of the pressure variation adjacent to the outer periphery substantially coincides with the position of the apertures 230.
Accordingly, as illustrated in
Therefore, according to the fluid control device 10, adverse influence of the vibration on the pressure distribution can be reduced. As a result, the fluid control device 10 has good flow rate characteristics.
As illustrated in
The fluid control device 10P according to the related art is structured such that the pump chamber 100 communicates with the outside of the first main plate 20P through the apertures 240. Therefore, the pressure is P(0)=0 at the position of the apertures 240. At the time illustrated in
Thus, according to the fluid control device 10P of the related art, in a region near the apertures 240, the pressure is a positive pressure P(+) but the displacement of the first main plate 20P is in the direction away from the pump chamber 100. Therefore, according to the fluid control device 10P of the related art, the shape of the vibration has adverse influence on the pressure distribution in the region near the apertures 240. As a result, the fluid control device 10P according to the related art does not have good flow rate characteristics.
According to the fluid control device 10 of the present disclosure, the shape of the vibration does not have adverse influence on the pressure distribution at any position. Therefore, good flow rate characteristics can be achieved.
In addition, according to the above-described structure, the first main plate 20 is a substantially circular plate. Therefore, the fluid control device 10 has low vibration energy loss.
In addition, according to the above-described structure, the apertures 230 are arranged along the entire circumference of the first main plate 20. Accordingly, the vibration energy is evenly distributed in all directions, and the flow rate characteristics of the fluid control device 10 can be improved.
A fluid control device according to a second embodiment of the present disclosure will now be described with reference to the drawings.
As illustrated in
The second connecting portion 24A is formed separately from the first frame 21 and the second frame 22. The second connecting portion 24A is a substantially annular elastic body. The material of the second connecting portion 24A is, for example, silicone rubber. The second connecting portion 24A may have any shape and be made of any material as long as the modulus of elasticity of the second connecting portion 24A is less than the modulus of elasticity of the first connecting portions 23. The second connecting portion 24A is joined to the first frame 21 and the second frame 22.
Similar to the fluid control device 10, the fluid control device 10A having the above-described structure also has good flow rate characteristics. The second connecting portion 24A of the above-described structure may have no apertures. When the second connecting portion 24A has no apertures, the pump chamber 100 can be appropriately sealed.
Fluid control devices according to a third embodiment of the present disclosure will now be described with reference to the drawings.
As illustrated in
As illustrated in
More specifically, as illustrated in
As illustrated in
According to the above-described structure, the flow rate characteristics of the fluid control devices 10B and 10C can be further improved.
Fluid control devices according to a fourth embodiment of the present disclosure will now be described with reference to the drawings.
As illustrated in
As illustrated in
More specifically, as illustrated in
As illustrated in
According to the above-described structure, the flow rate characteristics of the fluid control devices 10D and 10E can be further improved.
A fluid control device according to a fifth embodiment of the present disclosure will now be described with reference to the drawings.
As illustrated in
The fluid control device 10F is structured such that the thickness of the first connecting portions 23F is less than the thickness of the first main plate 20 and the thickness of the first frame 21. In other words, the first connecting portions 23F form a substantially annular recess that is recessed from the first main plate 20 and the first frame 21.
Also in the above-described structure, the flow passage resistance of the apertures 230 in the fluid control device 10F can be reduced. Therefore, the flow rate characteristics of the fluid control device 10F can be improved.
A fluid control device according to a sixth embodiment of the present disclosure will now be described with reference to the drawings.
As illustrated in
The fluid control device 10G additionally includes a film 61, a fixing member 62, a third main plate 71, an outer peripheral support member 72, and a flat membrane 80.
The film 61 is substantially annular. The film 61 is made of a flexible material, and is bent when an external force is applied thereto. The fixing member 62 is a substantially annular adhesive member. The film 61 is fixed to the first principal surface 201 of the first main plate 20 by the fixing member 62. More specifically, when fluid is introduced through the apertures 230 and discharged through apertures 400, as illustrated in
The third main plate 71 is disposed adjacent to the fourth principal surface 402 of the second main plate 40 with a gap provided between the third main plate 71 and the second main plate 40. The third main plate 71 faces the second main plate 40. The outer peripheral support member 72 is substantially annular and is connected to the second main plate 40 and the third main plate 71. Thus, a space 700 surrounded by the second main plate 40, the third main plate 71, and the outer peripheral support member 72 is provided. The third main plate 71 has apertures 710. The apertures 710 are holes that extend through the third main plate 71 in the thickness direction. The apertures 710 are arranged so as not to overlap the apertures 400.
The flat membrane 80 is shaped such that the flat membrane 80 can be disposed in the space 700. The thickness of the flat membrane 80 is less than the height of the space 700. The flat membrane 80 has apertures 810. The apertures 810 are arranged to overlap the apertures 710. According to this structure, the state of communication between the pump chamber 100 and the outside of the fluid control device 10G is set to either a communicated state or a non-communicated state depending on the direction in which the fluid flows through the apertures 400. Thus, a “second valve body” according to the present disclosure is realized.
Similar to the fluid control device 10, the fluid control device 10G having the above-described structure also has good flow rate characteristics. In addition, the fluid control device 10G also has a high rectifying effect.
Although the first valve body and the second valve body may both be provided, only one of the first valve body and the second valve body may instead be provided.
A fluid control device according to a seventh embodiment of the present disclosure will now be described with reference to the drawings.
As illustrated in
The fluid control device 10H includes the plurality of apertures 400H. The apertures 400H are disposed at the center of the second main plate 40 and on a circle centered on the center of the second main plate 40 and having a predetermined radius. As illustrated in
Similar to the fluid control device 10, the fluid control device 10H having the above-described structure also has good flow rate characteristics. In addition, according to the fluid control device 10H, the flow rate can be increased.
A fluid control device according to an eighth embodiment of the present disclosure will now be described with reference to the drawings.
As illustrated in
The fluid control device 10I includes a first main plate 201 having a substantially square shape in plan view. A first frame 211 and a second frame 221 are substantially rectangular ring-shaped in plan view.
First connecting portions 231 are connected to sides of the first main plate 201 and sides of the first frame 211. Second connecting portions 241 are connected to sides of the first frame 211 and sides of the second frame 221.
Similar to the fluid control device 10, the fluid control device 10I having the above-described structure also has good flow rate characteristics. The first main plate 201, the first frame 211, and the second frame 221 may instead have a substantially polygonal shape other than a substantially square (rectangular) shape, a substantially elliptical shape, or a substantially oval shape, but can have a shape close to a substantially circular shape. Also, the first main plate 201, the first frame 211, and the second frame 221 may have different shapes.
A fluid control device according to a ninth embodiment of the present disclosure will now be described with reference to the drawings.
As illustrated in
The fluid control device 10J includes the second main plate 40J. The second main plate 40J includes the projecting portion 41J, which is substantially annular, at the outer edge thereof. The projecting portion 41J is shaped to extend from the third principal surface 401 of the second main plate 40J in a direction away from the third principal surface 401. The projecting portion 41J is formed integrally with a flat plate portion of the second main plate 40J. The second main plate 40J is disposed such that a side thereof where the projecting portion 41J is provided (side of the third principal surface 401) faces the first main plate 20. The projecting portion 41J is in contact with the second frame 22. Thus, the pump chamber 100 is formed.
The fluid control device 10J having the above-described structure has effects similar to those of the fluid control device 10.
Although an example in which second-order vibration is generated is described above, the order of vibration is not limited to this.
In addition, in the above-described example, the shape (shape in plan view) of the apertures 230 is substantially circular. However, the apertures 230 may instead have, for example, a substantially polygonal, elliptical, or oval shape. The apertures 230 may instead be substantially band-shaped and extend in a circumferential direction of the first main plate.
The structures of each of the above-described embodiments may be combined as appropriate, and effects corresponding to the combinations can be obtained.
While embodiments of the disclosure have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without necessarily departing from the scope and spirit of the disclosure. The scope of the disclosure, therefore, is to be determined solely by the following claims.
Number | Date | Country | Kind |
---|---|---|---|
2019-179611 | Sep 2019 | JP | national |
Number | Name | Date | Kind |
---|---|---|---|
20130058818 | Hirata et al. | Mar 2013 | A1 |
20130266461 | Hirata | Oct 2013 | A1 |
20160377073 | Tanaka | Dec 2016 | A1 |
20170138357 | Kondo | May 2017 | A1 |
20170218949 | Yokoi et al. | Aug 2017 | A1 |
Number | Date | Country |
---|---|---|
2012-528981 | Nov 2012 | JP |
2013-053611 | Mar 2013 | JP |
5177331 | Apr 2013 | JP |
2019-039436 | Mar 2019 | JP |
2008126377 | Oct 2008 | WO |
2010139918 | Dec 2010 | WO |
Entry |
---|
Notice of Reasons for Rejection in Japanese Patent Application No. 2019-179611 dated Mar. 1, 2022. |
Number | Date | Country | |
---|---|---|---|
20210095659 A1 | Apr 2021 | US |