Patent Publication Number: US-2023140980-A1

Title: Fluid control device

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This is a continuation of International Application No. PCT/JP2021/016807 filed on Apr. 27, 2021 which claims priority from Japanese Patent Application No. 2020-122530 filed on Jul. 17, 2020 and Japanese Patent Application No. 2020-209762 filed on Dec. 18, 2020. The contents of these applications are incorporated herein by reference in their entireties. 
    
    
     BACKGROUND OF THE DISCLOSURE 
     Field of the Disclosure 
     The present disclosure relates to a fluid control device configured to convey a fluid in one direction. 
     Description of the Related Art 
     Patent Document 1 describes a fluid control device including a pump and a valve that are integrally formed with each other. The pump has a pump chamber having one surface formed by a vibration plate. The valve has a valve chamber communicating with the pump chamber. 
     A valve membrane is disposed in the valve chamber. A fluid flow causes the valve membrane to move in the valve chamber, thus rectifying the fluid flow. 
     Patent Document 1: Japanese Patent No. 6536770 
     BRIEF SUMMARY OF THE DISCLOSURE 
     Conceivable examples of a configuration in which a valve membrane is used as in the fluid control device described in Patent Document 1 include one in which a valve membrane is disposed in a pump chamber. In this case, the valve membrane parallel to a direction in which a fluid flows has one end and the other end, the one end being fixed to an inner wall of a pump, the other end being movable. When the fluid flows in a certain direction, the other end of the valve membrane moves toward a wall surface to which the valve membrane is fixed, and the fluid is conveyed. On the other hand, when the fluid tries to flow in the opposite direction, the other end of the valve membrane moves toward a wall surface facing the wall surface to which the valve membrane is fixed and comes into contact with this wall surface. Thus, the fluid flow is obstructed. Accordingly, the fluid flow is rectified. 
     However, in such a configuration in which a valve membrane is disposed in a pump chamber, a portion close to the other end of the valve membrane may come into contact with a corner of an outer peripheral end of a wall forming the pump chamber. Such contact causes a problem of wearing and damaging the valve membrane. 
     Accordingly, a possible benefit of the present disclosure is to provide a fluid control device capable of inhibiting a valve membrane from being worn and damaged. 
     A fluid control device of the present disclosure includes: a first flat plate having a first opening outside an outer peripheral end of the first flat plate; a frame disposed outside the outer peripheral end of the first flat plate; a connection member connecting the first flat plate and the frame; a second flat plate having a second opening in a portion facing the first flat plate, the second flat plate facing the first flat plate, the frame, and the connection member; a side wall member connecting the frame and the second flat plate, the side wall member forming a hollow chamber including a region that the first flat plate and the second flat plate face; a driver attached to the first flat plate; and a valve member set on a first surface, closer to a pump chamber, of the first flat plate, the valve member being configured to rectify a fluid flow. 
     An outer end of the valve member located closer to the outer peripheral end of the first flat plate projects toward an outside of the outer peripheral end. A portion of the valve member closer to an inner end thereof located closer to a center of the first flat plate is fixed to the first flat plate. The outer end of the valve member is not fixed. The valve member has a first portion forming a portion closer to the outer end, the first portion having a first thickness, and a second portion forming a portion closer to an inner end of the first portion, the second portion having a second thickness. The second thickness is larger than the first thickness. The second portion overlaps the outer peripheral end. 
     With this configuration, even when the valve member bends toward the first flat plate, the second portion comes into contact with a corner of the first flat plate. Since the second portion is thicker than the first portion, the valve member is less prone to being worn and damaged compared with the case in which the first portion comes into contact with the corner of the first flat plate. In addition, the thickness of the first portion is small, thus inhibiting deterioration of a rectifying function required for the valve member. 
     The present disclosure is capable of inhibiting a valve membrane from being worn and damaged. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG.  1    is an exploded perspective view of a fluid control device according to Embodiment 1. 
         FIG.  2    is a side sectional view illustrating the configuration of the fluid control device according to Embodiment 1. 
         FIG.  3    is an enlarged view of a region including an outer peripheral end of a first flat plate of the fluid control device according to Embodiment 1. 
         FIG.  4 A  is an enlarged view illustrating a fluid flow and the behavior of a valve member in a first state, and  FIG.  4 B  is an enlarged view illustrating a fluid flow and the behavior of the valve member in a second state. 
         FIG.  5    is a side sectional view illustrating the configuration of a fluid control device according to Embodiment 2. 
         FIG.  6 A  is a side sectional view illustrating the configuration of a fluid control device according to Embodiment 3, and  FIG.  6 B  is an enlarged view of a region including an outer peripheral end of a first flat plate of this fluid control device. 
         FIG.  7    is a side sectional view illustrating the configuration of a fluid control device according to Embodiment 4. 
         FIG.  8 A  is a plan view of a plate member of a fluid control device according to Embodiment 5, a driver being configured to be attached to the plate member, and  FIG.  8 B  is an enlarged plan view of a part where one connection member of this fluid control device is located. 
         FIG.  9    is an enlarged view of a region including an outer peripheral end of a first flat plate and a connection member of a fluid control device according to Embodiment 6. 
         FIGS.  10 A and  10 B  are enlarged perspective views of a region including the outer peripheral end of the first flat plate and the connection member of the fluid control device according to Embodiment 6. 
         FIG.  11    is an enlarged view of a region including an outer peripheral end of a first flat plate and a connection member of a fluid control device according to Embodiment 7. 
         FIG.  12    is an enlarged view of a region including an outer peripheral end of a first flat plate and a connection member of a fluid control device according to Embodiment 8. 
         FIG.  13    is an enlarged view of a region including an outer peripheral end of a first flat plate and a connection member of a fluid control device according to Embodiment 9. 
         FIG.  14    is an enlarged view of a region including an outer peripheral end of a first flat plate and a connection member of a fluid control device according to Embodiment 10. 
     
    
    
     DETAILED DESCRIPTION OF THE DISCLOSURE 
     Embodiment 1 
     A fluid control device according to Embodiment 1 of the present disclosure will be described with reference to the drawings.  FIG.  1    is an exploded perspective view of the fluid control device according to Embodiment 1.  FIG.  2    is a side sectional view illustrating the configuration of the fluid control device according to Embodiment 1.  FIG.  3    is an enlarged view of a region including an outer peripheral end of a first flat plate of the fluid control device according to Embodiment 1. In the respective drawings of the embodiments including the present embodiment, the entire or partial shapes of the respective components are illustrated in an exaggerated manner as appropriate to make the configuration of the fluid control device easy to understand. In the following embodiments, a view when a component having a main surface is viewed in a direction orthogonal to the main surface is referred to as plan view. 
     As illustrated in  FIGS.  1 ,  2 , and  3   , a fluid control device  10  includes a plate member  20 , a driver  30 , a plate member  40 , a side wall member  50 , and a valve member  60 . 
     Configuration of Plate Member  20   
     The plate member  20  is made of, for example, a metal plate and has a main surface  201  and a main surface  202 . The plate member  20  includes a first flat plate  21 , a frame  22 , and a plurality of connection members  23 . For example, the first flat plate  21 , the frame  22 , and the plurality of connection members  23  are integrally formed by one flat plate. 
     The first flat plate  21  has a plate-like shape. The first flat plate  21  has an outer peripheral portion including an outer peripheral end  210 , and a central portion located closer to the center thereof than the outer peripheral portion. The central portion is thicker than the outer peripheral portion. The shape of the first flat plate  21  in plan view (shape viewed in the thickness direction) is a circular shape. In the first flat plate  21 , the central portion projects at the main surface  202 . Conversely, in the first flat plate  21 , the central portion and the outer peripheral portion including the outer peripheral end form a plane at the main surface  201 . 
     The frame  22  is a flat plate. The shape of the frame  22  in plan view is a square. The frame  22  has an opening. The opening passes through the flat plate forming the frame  22  in the thickness direction. The opening has a circular shape in plan view. The shape of the opening is similar to the outer peripheral shape of the first flat plate  21  and is larger than the outer peripheral shape of the first flat plate  21 . The center of the frame  22  and the center of the opening coincide with each other. 
     The first flat plate  21  is disposed in the opening of the frame  22 . In this case, the center of the opening and the center of the first flat plate  21  coincide with each other. The area of the first flat plate  21  is smaller than the area of the opening of the frame  22 . Thus, even when the first flat plate  21  is disposed in the opening of the frame  22 , an opening remains between the outer peripheral end of the first flat plate  21  and the frame  22 . 
     The plurality of connection members  23  each have a beam shape. The plurality of connection members  23  are disposed in the opening between the first flat plate  21  and the frame  22 . The plurality of connection members  23  are disposed so as to be spaced along the outer peripheral end  210  of the first flat plate  21 . 
     The plurality of connection members  23  each include a first connection portion  231 , a second connection portion  232 , and third connection portions  233 . The first connection portion  231  has a shape extending in a radial direction. The radial direction is a direction outward from the outer peripheral end  210  of the first flat plate  21 . The second connection portion  232  has a circular arc shape extending along the outer peripheral end  210  of the first flat plate  21  in plan view (when viewed in a direction orthogonal to the main surface  201  and the main surface  202 ). The third connection portion  233  has a shape extending in a radial direction. 
     One end of the direction in which the first connection portion  231  extends is connected to the outer peripheral end  210  of the first flat plate  21 . The other end of the direction in which the first connection portion  231  extends is connected to substantially the center in the direction in which the second connection portion  232  extends. Both ends of the direction in which the second connection portion  232  extends are connected to the frame  22  via the respective third connection portions  233 . 
     With this configuration, the plurality of connection members  23  connect the first flat plate  21  and the frame  22  with openings  241  and openings  242  interposed therebetween. The openings  241  are each formed so as to include a region closer to the first flat plate  21  than the second connection portion  232 . The openings  242  are regions closer to the frame  22  than the second connection portion  232 . Each of the openings  241  and the openings  242  corresponds to a “first opening” of the present disclosure. 
     Then, with this configuration, the first flat plate  21  is supported in a state of being capable of performing bending vibration relative to the frame  22  via the plurality of connection members  23 . 
     For example, the driver  30  is a piezoelectric element and is attached to the first flat plate  21 . More specifically, the driver  30  is attached to the central portion of the first flat plate  21 . 
     The plate member  40  has a main surface  401  and a main surface  402 . The plate member  40  has a recessed portion recessed from the main surface  401 . The bottom of the recessed portion has a plurality of through holes  400 . The plurality of through holes  400  are disposed in a circular shape in plan view (when viewed in a direction orthogonal to the main surface  401  and the main surface  402 ). The diameter of the circle in which the plurality of through holes  400  are disposed is smaller than the diameter of the first flat plate  21 . The plate member  40  corresponds to a “second flat plate” of the present disclosure. 
     The plate member  40  is disposed so as to be spaced from the plate member  20  such that the main surface  401  faces the main surface  201 . In this case, the plate member  40  is disposed such that the plurality of through holes  400  overlap the first flat plate  21 . 
     The side wall member  50  has a hollow  500  and has a loop shape. The side wall member  50  is disposed between the plate member  20  and the plate member  40 . The side wall member  50  is connected to the frame  22  and the plate member  40 . 
     Thus, the hollow chamber surrounded by the plate member  20 , the side wall member  50 , and the plate member  40  is formed and functions as a pump chamber  100 . The pump chamber  100  communicates, through the plurality of through holes  400 , with a space outside the fluid control device  10  closer to the plate member  40 . In addition, the pump chamber  100  communicates, through the plurality of openings  241  and  242 , with a space outside the fluid control device  10  closer to the plate member  20 . 
     The valve member  60  includes a valve membrane  61  and a fixing layer  62 . The valve membrane  61  and the fixing layer  62  each have a circular shape. That is, the external shape of the valve membrane  61  and the external shape of the fixing layer  62  are similar to the external shape (outer peripheral shape) of the first flat plate  21  and the shape formed by connecting the plurality of second connection portions  232  of the connection members  23 . The external shape of the valve membrane  61  and the external shape of the fixing layer  62  are larger than the external shape of the first flat plate  21 . 
     The valve membrane  61  bends more easily than the fixing layer  62 . The fixing layer  62  bends more easily than the first flat plate  21 . The relationship of the easiness of bending between these components is controlled by each material for the valve membrane  61 , the fixing layer  62 , and the first flat plate  21  and each thickness of the valve membrane  61 , the fixing layer  62 , and the first flat plate  21 . For example, the first flat plate  21  is made of a metal. The fixing layer  62  has a bending modulus higher than that of the valve membrane  61 . In addition, the fixing layer  62  is thicker than the valve membrane  61 . 
     The valve membrane  61  is fixed to the main surface  201  of the first flat plate  21  with the fixing layer  62 . In this case, the center of the valve membrane  61 , the center of the fixing layer  62 , and the center of the first flat plate  21  substantially coincide with each other. In this case, since the external shape of the valve membrane  61  and the external shape of the fixing layer  62  are larger than the external shape of the first flat plate  21 , the valve member  60  formed by the external shape of the valve membrane  61  and the external shape of the fixing layer  62  has a projection projecting toward the outside of the outer peripheral end of the first flat plate  21 . 
     The diameter of the valve membrane  61  is larger than the diameter of the fixing layer  62 . Thus, a circular-shaped region of the valve membrane  61  closer to the center is fixed, and a ring-shaped region of the valve membrane  61  closer to an outer end  610  is not fixed. In other words, in a state in which the outer end  610  is not fixed, the valve membrane  61  is fixed to the first flat plate  21  with the fixing layer  62 . A portion formed by only the valve membrane  61  corresponds to a “first portion of the valve member” of the present disclosure. A portion formed by laminating the valve membrane  61  and the fixing layer  62  corresponds to a “second portion of the valve member” of the present disclosure. A portion where the fixing layer  62  and the first flat plate  21  are in contact with each other corresponds to a “fixed portion” of the present disclosure. 
     The diameter of the fixing layer  62  is larger than the diameter of the first flat plate  21 . Thus, as illustrated in  FIGS.  2  and  3   , an outer end  620  of the fixing layer  62  is located outside the outer peripheral end  210  of the first flat plate  21 . In other words, in plan view, the outer end  620  of the fixing layer  62  overlaps the openings  241 . In still other words, when the valve member is viewed in plan view, the portion (boundary portion) where the first portion of the valve member and the second portion of the valve member are connected does not overlap the first flat plate  21 , is located outside the outer peripheral end  210  of the first flat plate  21 , and overlaps the openings  241 . 
     In this configuration, the fluid control device  10  rectifies a fluid flow as follows.  FIG.  4 A  is an enlarged view illustrating a fluid flow and the behavior of the valve member in a first state.  FIG.  4 B  is an enlarged view illustrating a fluid flow and the behavior of the valve member in a second state. 
     As illustrated in  FIG.  4 A , in the first state of the fluid control device  10 , a fluid is suctioned from the outside closer to the plate member  40  into the pump chamber  100  via the plurality of through holes  400 . The fluid flows in the pump chamber  100  in a direction from the central portion of the first flat plate  21  toward the outer peripheral end  210  (toward the side wall member  50 ). 
     A portion of the valve membrane  61  closer to the center thereof is fixed, and the outer end  610  of the valve membrane  61  is not fixed. Thus, the valve membrane  61  is bent by the fluid toward the first flat plate  21 , in other words, toward the openings  241  and the connection members  23 . As a result of this, the fluid flows from the pump chamber  100  into the openings  241  and is discharged from the openings  241  to the outside closer to the plate member  20 . The fluid is also discharged from the openings  242  to the outside closer to the plate member  20 . 
     As illustrated in  FIG.  4 B , in the second state of the fluid control device  10 , a fluid is suctioned from the outside closer to the plate member  20  into the pump chamber  100  via the openings  241  and the openings  242 . The fluid tries to flow in the pump chamber  100  in a direction from the outer peripheral end  210  of the first flat plate  21  (side wall member  50 ) toward the central portion of the first flat plate  21 . 
     In this case, the valve membrane  61  is bent by the fluid toward the plate member  40 . Then, a portion of the valve membrane  61  that has a predetermined area and that is closer to the outer end  610  comes into contact with the main surface  401  of the plate member  40 . This obstructs the fluid flow toward the center of the pump chamber  100 . Thus, the fluid does not reach the plurality of through holes  400  and is inhibited from being discharged to the outside closer to the plate member  40 . 
     In this manner, the fluid control device  10  has a rectifying function of causing a fluid to flow in one direction. 
     The fluid control device  10  further has the following feature. The fluid control device  10  has the above configuration. Thus, a thickness D 602  of the valve member  60  at a position overlapping the outer peripheral end  210  of the first flat plate  21  is larger than a thickness D 601  of the outer end  610  (D 602 &gt;D 601 ). 
     As illustrated in  FIG.  4 A , in this configuration, when the valve membrane  61  bends toward the first flat plate  21 , the portion that comes into contact with a corner of the outer peripheral end  210  of the first flat plate  21  is a portion having the thickness D 602 . That is, a portion thicker than the portion that is formed by only the valve membrane  61  and that includes the outer end  610  comes into contact with the corner of the outer peripheral end  210  of the first flat plate  21 . 
     Thus, the portion of the valve member  60  that comes into contact with the corner of the outer peripheral end  210  of the first flat plate  21  is harder than and less prone to being worn than the outer end  610 . This enables the fluid control device  10  to inhibit the valve member  60  from being worn and damaged. 
     In this configuration, the portion of the valve member  60  formed by laminating the valve membrane  61  and the fixing layer  62  is less prone to bending. The portion of the valve member  60  formed by laminating the valve membrane  61  and the fixing layer  62  is less prone to bending but bends more easily than the first flat plate  21 . Thus, the deterioration of the rectifying function can be inhibited by appropriately setting the length of the portion of the fixing layer  62  projecting from the outer peripheral end  210  of the first flat plate  21  and the length of the portion of the valve membrane  61  projecting from the outer end  620  of the fixing layer  62  to form the valve member  60 . That is, the fluid control device  10  is excellent in reliability by inhibiting the wear and damage and is capable of achieving a good rectifying function. 
     Then, in this configuration, the bending stress applied to the valve membrane  61  is dispersed by bending the fixing layer  62 . Thus, it is possible to inhibit, at the outer end  620  of the fixing layer  62 , the separation of the fixing layer  62  and the valve membrane  61  and the occurrence of the cracks in the valve membrane  61 . 
     In addition, a configuration in which the fixing layer  62  is thicker than the valve membrane  61  has been described in the present embodiment, but the configuration is not limited thereto. It is sufficient that the portion of the valve member  60  that comes into contact with the corner of the outer peripheral end  210  of the first flat plate  21  be thicker than the portion of the valve member  60  that includes the outer peripheral end and that mainly achieves the rectifying function. 
     Furthermore, in other words, it is sufficient that the portion of the valve member  60  that comes into contact with the corner of the outer peripheral end  210  of the first flat plate  21  bend more easily than the first flat plate  21  and that the portion of the valve member  60  that includes the outer peripheral end and that mainly achieves the rectifying function bend more easily than the portion of the valve member  60  that comes into contact with the corner of the outer peripheral end  210  of the first flat plate  21 . 
     In addition, a configuration in which the fixing layer  62  projects from the outer peripheral end  210  of the first flat plate  21  has been described. However, the outer end  620  of the fixing layer  62  and the outer peripheral end  210  of the first flat plate  21  may coincide with each other. However, even when the position where the fixing layer  62  is set on the first flat plate  21  varies, the fixing layer  62  projecting from the outer peripheral end  210  of the first flat plate  21  is capable of inhibiting the outer end  620  of the fixing layer  62  from being located closer to the center than the outer peripheral end  210  of the first flat plate  21 . 
     In addition, in this configuration, the shape of the outer peripheral end  210  of the first flat plate  21 , the shape of the outer end  620  of the fixing layer  62 , and the shape of the outer end  610  of the valve membrane  61  are similar circular shapes. In addition, the plurality of through holes  400  are disposed in a circular shape. As a result of this, a fluid flows substantially evenly in all directions in plan view, thus improving the efficiency of the fluid control device  10 . 
     Embodiment 2 
     A fluid control device according to Embodiment 2 of the present disclosure will be described with reference to the drawing.  FIG.  5    is a side sectional view illustrating the configuration of the fluid control device according to Embodiment 2. 
     As illustrated in  FIG.  5   , a fluid control device  10 A according to Embodiment 2 differs from the fluid control device  10  according to Embodiment 1 in that the fluid control device  10 A has recessed portions  241 A instead of the openings  241 . The other configurations of the fluid control device  10 A are similar to those of the fluid control device  10 , and descriptions of similar parts are omitted. 
     The recessed portion  241 A is disposed between the first flat plate  21  and the second connection portion  232  of the connection member  23 . The recessed portion  241 A has a shape recessed from the main surface  201  of the plate member  20 . In other words, the recessed portion  241 A has a shape formed by closing an opening portion, opposite to the valve member  60 , of the opening  241  according to Embodiment 1. 
     As with the fluid control device  10 , this configuration enables the fluid control device  10 A to inhibit the valve member  60  from being worn and damaged. 
     Embodiment 3 
     A fluid control device according to Embodiment 3 of the present disclosure will be described with reference to the drawings.  FIG.  6 A  is a side sectional view illustrating the configuration of the fluid control device according to Embodiment 3.  FIG.  6 B  is an enlarged view of a region including an outer peripheral end of a first flat plate of this fluid control device. 
     As illustrated in  FIGS.  6 A and  6 B , a fluid control device  10 B according to Embodiment 3 differs from the fluid control device  10  according to Embodiment 1 in the configuration of a valve member  60 B. The other configurations of the fluid control device  10 B are similar to those of the fluid control device  10 , and descriptions of similar parts are omitted. 
     The valve member  60 B includes a valve membrane  61 B and a fixing layer  62 B. The valve membrane  61 B is fixed to the main surface  201  of the first flat plate  21  with the fixing layer  62 B. 
     The external shape of the fixing layer  62 B is smaller than the external shape of the first flat plate  21 . More specifically, the diameter of the fixing layer  62 B is smaller than the diameter of the first flat plate  21 . 
     The valve membrane  61 B includes a first portion including the outer end  610 , and a second portion located closer to the center thereof than the first portion. A thickness D 602 B of the second portion is larger than the thickness D 601  of the first portion. 
     The portion where the second portion and the first portion are connected (portion whose thickness varies) is located outside the outer peripheral end  210  of the first flat plate  21 . 
     In this configuration, even when the outer end  620  of the fixing layer  62 B is located closer to the center than the outer peripheral end  210  of the first flat plate  21 , the portion of the valve membrane  61 B overlapping the outer peripheral end  210  of the first flat plate  21  is the second portion, that is, a thick portion of the valve membrane  61 B. 
     Thus, even when the valve membrane  61 B bends toward the outer peripheral end  210  of the first flat plate  21  and comes into contact with the corner of the outer peripheral end  210 , it is possible to inhibit the valve membrane  61 B from being worn and damaged. In this case, as illustrated in  FIG.  6 B , the position of the outer end of the second portion is preferably located outside the outer peripheral end  210  of the first flat plate  21  so as to be away therefrom substantially by a thickness D 62  of the fixing layer  62 B. As a result of this, when the valve membrane  61 B comes into contact with the corner of the outer peripheral end  210 , the second portion more reliably comes into contact with the corner of the outer peripheral end  210 . Thus, it is possible to more reliably inhibit the valve membrane  61 B from being worn and damaged. 
     Embodiment 4 
     A fluid control device according to Embodiment 4 of the present disclosure will be described with reference to the drawing.  FIG.  7    is a side sectional view illustrating the configuration of the fluid control device according to Embodiment 4. 
     As illustrated in  FIG.  7   , a fluid control device  10 C according to Embodiment 4 differs from the fluid control device  10  according to Embodiment 1 mainly in the shape and the disposition of a valve member  60 C. In addition, the fluid control device  10 C differs from the fluid control device  10  in the shape of each of a plate member  20 C and a plate member  40 C. The other configurations of the fluid control device  10 C are similar to those of the fluid control device  10 , and descriptions of similar parts are omitted. 
     The fluid control device  10 C includes the plate member  20 C, the plate member  40 C, and the valve member  60 C. The plate member  20 C includes a first flat plate  21 C. The first flat plate  21 C has a uniform thickness. 
     The plate member  40 C has a uniform thickness. A through hole  400 C is formed at the center when the plate member  40 C is viewed in plan view. The through hole  400 C passes through the plate member  40 C in the thickness direction (direction orthogonal to the main surface  401  and the main surface  402 ). For example, the through hole  400 C has a cylindrical shape. 
     The valve member  60 C includes a valve membrane  61 C and a fixing layer  62 C. 
     The valve membrane  61 C has a ring shape and has an opening  619 , which has a circular shape. The outer diameter (diameter) of the valve membrane  61 C is larger than the diameter of the through hole  400 C. The diameter of the opening  619  is smaller than the diameter of the through hole  400 C. 
     The outer diameter (diameter) of the fixing layer  62 C is larger than the diameter of the through hole  400 C. The diameter of an opening  629  is smaller than the diameter of the through hole  400 C and larger than the diameter of the opening  619  of the valve membrane  61 C. 
     The valve membrane  61 C is fixed to the main surface  401 , which is a main surface of the plate member  40 C closer to the pump chamber, via the fixing layer  62 C. In this case, the center of the opening  619  of the valve membrane  61 C, the center of the opening  629  of the fixing layer  62 C, and the center of the through hole  400 C substantially coincide with each other in plan view. 
     With this configuration, a region of the valve membrane  61 C closer to the outer end thereof is fixed to the main surface  401  via the fixing layer  62 C. Thus, in the case of the fluid control device  10 C, when a fluid is suctioned from the openings  241  and the openings  242 , the valve member  60 C bends so as to enter the through hole  400 C. Then, the fluid is discharged from the through hole  400 C to the outside. On the other hand, when a fluid is suctioned from the through hole  400 C, the valve member  60 C bends toward the plate member  20 C, and a region of the valve membrane  61 C closer to an inner end  610 C comes into contact with the main surface  201  of the plate member  20 C. Thus, the fluid does not flow in directions toward the outer peripheral end  210  of the plate member  20 C. 
     In this manner, the fluid control device  10 C has a rectifying function of causing a fluid to flow in one direction. 
     In the case of the fluid control device  10 C, in plan view, the inner end  610 C of the valve membrane  61 C and an inner end  620 C of the fixing layer  62 C are located further inside (closer to the center) of the through hole  400 C than a wall  410  of the through hole  400 C. In addition, the inner end  610 C of the valve membrane  61 C is located inside the inner end  620 C of the fixing layer  62 C. 
     Thus, even when the valve member  60 C bends toward the through hole  400 C, the fixing layer  62 C comes into contact with the corner of the wall  410  of the through hole  400 C closer to the pump chamber  100 , and the valve membrane  61 C does not come into contact with the corner of the wall  410 . This enables the fluid control device  10 C to inhibit the valve membrane  61 C from being worn and damaged. 
     Embodiment 5 
     A fluid control device according to Embodiment 5 of the present disclosure will be described with reference to the drawings.  FIG.  8 A  is a plan view of a plate member of the fluid control device according to Embodiment 5, a driver being configured to be attached to the plate member.  FIG.  8 B  is an enlarged plan view of a part where one connection member of this fluid control device is located. 
     As illustrated in  FIGS.  8 A and  8 B , the fluid control device according to Embodiment 5 differs from the fluid control device  10  according to Embodiment 1 in the shape of connection members  23 D of a plate member  20 D. The other configurations of the fluid control device according to Embodiment 5 are similar to those of the fluid control device  10 , and descriptions of similar parts are omitted. 
     As illustrated in  FIGS.  8 A and  8 B , the connection members  23 D each include a first connection portion  231 D, the second connection portion  232 , and the third connection portions  233 . The first connection portion  231 D has an inner end portion  2311 , a joint portion  2312 , and an outer end portion  2313 . The inner end portion  2311  is connected to the outer peripheral end  210  of the first flat plate  21 . The outer end portion  2313  is connected to the second connection portion  232 . The joint portion  2312  is connected to the inner end portion  2311  and the outer end portion  2313 . 
     The joint portion  2312  has a shape that becomes wider from the end thereof closer to the inner end portion  2311  toward the end thereof closer to the outer end portion  2313 . 
     As illustrated in  FIG.  8 B , this configuration enables an increase in the area of the part of the joint portion  2312  with which the outer end  610  of the valve membrane  61  comes into contact. Thus, even when the valve membrane  61  comes into contact with the joint portion  2312 , it is possible to inhibit the valve membrane  61  from being worn and damaged. 
     The inner end portion  2311  has no corners in the portion where the inner end portion  2311  and the first flat plate  21  are connected. The inner end portion  2311  has a shape that becomes gradually narrower toward the joint portion  2312 . In addition, the inner end portion  2311  is connected to the joint portion  2312  without corners. 
     The outer end portion  2313  has no corners in the portion where the outer end portion  2313  and the second connection portion  232  are connected. The outer end portion  2313  has a shape that becomes gradually narrower toward the joint portion  2312 . In addition, the outer end portion  2313  is connected to the joint portion  2312  without corners. 
     With these configurations, the outer end  620  of the fixing layer  62  and the outer end  610  of the valve membrane  61  do not come into contact with corners. Thus, it is possible to further inhibit the valve membrane  61  and the fixing layer  62  from being worn and damaged. 
     Embodiment 6 
     A fluid control device according to Embodiment 6 of the present disclosure will be described with reference to the drawings.  FIG.  9    is an enlarged view of a region including an outer peripheral end of a first flat plate and a connection member of the fluid control device according to Embodiment 6.  FIGS.  10 A and  10 B  are enlarged perspective views of a region including the outer peripheral end of the first flat plate and the connection member of the fluid control device according to Embodiment 6.  FIG.  10 A  illustrates a state in which a valve membrane is disposed.  FIG.  10 B  illustrates a state in which the valve membrane is detached. 
     As illustrated in  FIGS.  9 ,  10 A, and  10 B , a fluid control device  10 E according to Embodiment 6 differs from the fluid control device  10  according to Embodiment 1 in the shape of a first connection portion  231 E of a connection member. The other configurations of the fluid control device  10 E are similar to those of the fluid control device  10 , and descriptions of similar parts are omitted. 
     The first connection portion  231 E has a recessed portion  2310 , which is recessed from the main surface  201  of the first flat plate  21  relative to the first flat plate  21  and the second connection portion  232 . In other words, the first connection portion  231 E has the recessed portion  2310 , which is recessed from the surface of the first flat plate  21  where the valve member  60  is disposed and which is located in a portion overlapping the outer end  610  of the valve member  60  and the first portion (portion formed by only the valve membrane  61 ) of the valve member  60  when the valve member  60  is viewed in plan view. 
     With this configuration, the first portion of the valve member  60  is less prone to coming into contact with the first connection portion  231 E. This enables the fluid control device  10 E to further inhibit the valve membrane  61  from being worn and damaged. 
     Embodiment 7 
     A fluid control device according to Embodiment 7 of the present disclosure will be described with reference to the drawing.  FIG.  11    is an enlarged view of a region including an outer peripheral end of a first flat plate and connection members of the fluid control device according to Embodiment 7. 
     As illustrated in  FIG.  11   , a fluid control device  10 F according to Embodiment 7 differs from the fluid control device  10 E according to Embodiment 6 in the shape of a first connection portion  231 F of a connection member. The other configurations of the fluid control device  10 F are similar to those of the fluid control device  10 E, and descriptions of similar parts are omitted. 
     The first connection portion  231 F has a curved surface in an opening portion of the recessed portion  2310  closer to the first flat plate  21 . In other words, the recessed portion  2310  has a shape that becomes gradually deeper from the end of the recessed portion  2310  closer to the first flat plate  21  toward the center of the recessed portion  2310 . 
     With this configuration, even when the valve member  60  bends toward the first connection portion  231 F and the first flat plate  21 , the valve member  60  does not come into contact with a sharp corner. This enables the fluid control device  10 F to further inhibit the valve membrane  61  from being worn and damaged. 
     Embodiment 8 
     A fluid control device according to Embodiment 8 of the present disclosure will be described with reference to the drawing.  FIG.  12    is an enlarged view of a region including an outer peripheral end of a first flat plate and a connection member of the fluid control device according to Embodiment 8. 
     As illustrated in  FIG.  12   , a fluid control device  10 G according to Embodiment 8 differs from the fluid control device  10 E according to Embodiment 6 in the shape of a first connection portion  231 G of a connection member. The other configurations of the fluid control device  10 G are similar to those of the fluid control device  10 E, and descriptions of similar parts are omitted. 
     The first connection portion  231 G bends in the middle in the direction connecting the first flat plate  21  and the second connection portion  232  so as to project from the main surface  202  of the first flat plate  21 . 
     This configuration facilitates provision of the first connection portion  231 G having a predetermined thickness and having the recessed portion  2310 . Thus, the first connection portion  231 G is capable of having a predetermined strength. This enables the fluid control device  10 G to further inhibit the valve membrane  61  from being worn and damaged and to inhibit a reduction in reliability. 
     Embodiment 9 
     A fluid control device according to Embodiment 9 of the present disclosure will be described with reference to the drawing.  FIG.  13    is an enlarged view of a region including an outer peripheral end of a first flat plate and a connection member of the fluid control device according to Embodiment 9. 
     As illustrated in  FIG.  13   , a fluid control device  10 H according to Embodiment 9 differs from the fluid control device  10 E according to Embodiment 6 in the shape of each of a first flat plate  21 H and a recessed portion  2310 H. The other configurations of the fluid control device  10 H are similar to those of the fluid control device  10 E, and descriptions of similar parts are omitted. The shape of a first connection portion  231 H of the fluid control device  10 H is similar to that of the first connection portion  231 E of the fluid control device  10 E, and a description thereof is omitted. 
     The first flat plate  21 H has a recessed portion recessed from the main surface  201  at the outer peripheral end  210 . This recessed portion of the first flat plate  21 H communicates with a recessed portion of the first connection portion  231 H, thus forming the recessed portion  2310 H. In other words, the recessed portion  2310 H extends from the first connection portion  231 H to the inside of the outer peripheral end  210  of the first flat plate  21 H. 
     This configuration enables the fluid control device  10 H to further inhibit the valve membrane  61  from being worn and damaged. 
     Embodiment 10 
     A fluid control device according to Embodiment 10 of the present disclosure will be described with reference to the drawing.  FIG.  14    is an enlarged view of a region including an outer peripheral end of a first flat plate and a connection member of the fluid control device according to Embodiment 10. 
     As illustrated in  FIG.  14   , a fluid control device  10 I according to Embodiment 10 differs from the fluid control device  10 E according to Embodiment 6 in the configuration in which a first flat plate  21 I and the connection member are connected. The other configurations of the fluid control device  10 I are similar to those of the fluid control device  10 E, and descriptions of similar parts are omitted. 
     A first connection portion  231 I is connected to the main surface  202  in the vicinity of the outer peripheral end  210  of the first flat plate  21 I. With this configuration, the depth of the recessed portion  2310  is equal to or larger than the thickness of the first flat plate  21 I. 
     This configuration enables the fluid control device  10 I to further inhibit the valve membrane  61  from being worn and damaged. 
     Examples of a first flat plate having a circular shape and a valve member having a circular shape or a ring shape have been described in the above embodiments. However, these components may have polygonal shapes, preferably regular polygonal shapes having a large number of angles. However, such a circular shape enables a fluid control device to improve in efficiency. 
     In addition, configurations in which the shape of a first flat plate and the shape of a valve membrane are similar to each other have been described in the above embodiments. However, for example, the combination of the shapes of these components may be a combination of a circular shape and a regular polygonal shape. However, such similar shapes enable a fluid control device to improve in efficiency. 
     Furthermore, the shape of a valve membrane and the shape formed by second connection portions of connection members that are similar to each other improve the efficiency of a fluid passing through the opening  241 , thus enabling a fluid control device to improve in efficiency. 
     In addition, a configuration in which a driver is set on a first flat plate has been described above. However, a configuration in which a driver is set on a plate member (second flat plate) may be used. 
     In addition, the configurations of the above embodiments can be combined as appropriate. It is possible to achieve functions and effects according to respective combinations.
       10 ,  10 A,  10 B,  10 C,  10 E,  10 F,  10 G,  10 H,  10 I fluid control device     20 ,  20 C,  20 D plate member     21 ,  21 C,  21 H,  21 I first flat plate     22  frame     23 ,  23 D connection member     30  driver     40 ,  40 C plate member     50  side wall member     60 ,  60 B,  60 C valve member     61 ,  61 B,  61 C valve membrane     62 ,  62 B,  62 C fixing layer     100  pump chamber     201 ,  202  main surface     210  outer peripheral end     231 ,  231 D,  231 E,  231 F,  231 G,  231 H,  231 I first connection portion     232  second connection portion     233  third connection portion     241 ,  242  opening     241 A recessed portion     400 ,  400 C through hole     401 ,  402  main surface     410  wall     500  hollow     610  outer end     610 C inner end     619  opening     620  outer end     620 C inner end     629  opening     2310 ,  2310 H recessed portion     2311  inner end portion     2313  outer end portion