Pump having a top portion fixed to an external structure
A fluid control device includes a pump and an external structure. The pump includes an actuator, a top portion opposed to the actuator such that a gap is disposed therebetween in the thickness direction, and a side wall plate extending from the top portion in the thickness direction and supporting a vibration member. The actuator includes the plate-like vibration member and a piezoelectric element configured to cause the vibration member to vibrate in the thickness direction. The top portion includes a projection portion and a fixation portion projecting beyond the side wall plate in an outward direction perpendicular to the thickness direction. The top portion is fixed to an external structure outside the projection portion.
1. A pump comprising:
a vibration plate comprising a vibration member configured to vibrate in a thickness direction, and at least one channel hole;
a side wall portion that supports an end portion of the vibration plate;
a top portion supported by the side wall portion; and
a space delimited by the top portion, the vibration plate, and the side wall portion,
wherein the top portion includes:
a top surface portion facing the vibration plate such that a gap is disposed therebetween in the thickness direction,
a joint portion extending from the top surface portion in an outward direction perpendicular to the thickness direction and joined to the side wall portion,
a projection portion extending from the joint portion in the outward direction and projecting beyond the side wall portion, and
a fixation portion extending from the projection portion in the outward direction and fixed to an external structure, wherein the projection portion has no opening.
2. The pump according to claim 1 , wherein the projection portion includes a first thin portion that is thinner than the joint portion.
3. The pump according to claim 2 , wherein a following conditional expression is satisfied,
0.05 t (2/3) ≤d≤ 0.066 t (2/3)
where d denotes a dimension of the projection portion in the outward direction, and t denotes a dimension of the projection portion in the thickness direction.
4. A fluid control device comprising:
the pump according to claim 2 ; and
the external structure.
5. The pump according to claim 2 , wherein the first thin portion is arranged in a ring shape.
6. The pump according to claim 5 , wherein a following conditional expression is satisfied,
0.05 t (2/3) ≤d≤ 0.066 t (2/3)
where d denotes a dimension of the projection portion in the outward direction, and t denotes a dimension of the projection portion in the thickness direction.
7. A fluid control device comprising:
the pump according to claim 5 ; and
the external structure.
8. The pump according to claim 2 , wherein the projection portion includes a second thin portion that is thinner than the joint portion, and
a distance from a central axis of the top surface portion to the first thin portion differs from a distance from the central axis of the top surface portion to the second thin portion.
9. The pump according to claim 8 , wherein a following conditional expression is satisfied,
0.05 t (2/3) ≤d≤ 0.066 t (2/3)
where d denotes a dimension of the projection portion in the outward direction, and t denotes a dimension of the projection portion in the thickness direction.
10. A fluid control device comprising:
the pump according to claim 8 ; and
the external structure.
11. The pump according to claim 1 , wherein a following conditional expression is satisfied,
0.05 t (2/3) ≤d≤ 0.066 t (2/3)
where d denotes a dimension of the projection portion in the outward direction, and t denotes a dimension of the projection portion in the thickness direction.
12. The pump according to claim 11 , wherein a following conditional expression 0.06 t (2/3) ≤d≤0.066 t (2/3) is satisfied.
13. A fluid control device comprising:
the pump according to claim 1 ; and
the external structure.
14. The fluid control device according to claim 13 , wherein the top surface portion has a plurality of channel holes communicating with the space, and
the external structure is a valve housing including a valve for opening or closing the plurality of channel holes.
15. The pump according to claim 1 , further comprising an inlet and an outlet, wherein:
the inlet and outlet are in fluid communication with each other via the space delimited by the top portion, vibration plate, and side wall portion, and
the projection portion of the top portion is outside of the space.
16. The pump according to claim 1 , wherein the projection portion is annular.
17. The pump according to claim 1 , wherein the gap has a first thickness along a central portion of the top surface portion and a second thickness along a peripheral portion of the top surface portion that is less than the first thickness.
18. The pump according to claim 1 , wherein the top potion includes a first plate that defines one or more channel holes and a second plate that defines a second plate opening, the second plate opening having a diameter that is greater than a diameter of each channel hole.
19. The pump according to claim 18 , wherein the side wall portion defines a side wall portion opening having a diameter that is greater than the diameter of the second plate opening.