A pump includes a housing, a first vibrating body, a second vibrating body, and a peripheral wall portion that define a pump chamber, and a driving body. The housing has a first wall portion opposed to the first vibrating body and a second wall portion. The first wall portion includes a first concave portion that opens toward the first vibrating body and opposed to a central portion of the first vibrating body and a first circumferential portion adjacent to the first concave portion. A first chamber includes a first wide portion defined by the first concave portion and the first vibrating body, and a first narrow portion defined by the first circumferential portion and the first vibrating body. The first narrow portion overlaps with at least part of the first vibrating body.

A pump includes a housing, a first vibrating body, a second vibrating body, and a peripheral wall portion that define a pump chamber, and a driving body. The housing has a first wall portion opposed to the first vibrating body and a second wall portion. The first wall portion includes a first concave portion that opens toward the first vibrating body and opposed to a central portion of the first vibrating body and a first circumferential portion adjacent to the first concave portion. A first chamber includes a first wide portion defined by the first concave portion and the first vibrating body, and a first narrow portion defined by the first circumferential portion and the first vibrating body. The first narrow portion overlaps with at least part of the first vibrating body.

A pump includes a first pump chamber formed by a first plate member and a second plate member, a second pump chamber formed by a first plate member and a third plate member, and a driving member. The driving member causes the first plate member to perform flexural vibration, thereby causing pressure changes in both of the first pump chamber and the second pump chamber. The first plate member is provided with first hole portions not overlapping an axial line orthogonal to a central region of the first plate member, and a check valve is provided to each of the first hole portions. The second plate member and the third plate member are provided with a second hole portion and a third hole portion respectively, and the check valve is provided to at least one of the second hole portion and the third hole portion.

A pump includes a first pump chamber formed by a first plate member and a second plate member, a second pump chamber formed by a first plate member and a third plate member, and a driving member. The driving member causes the first plate member to perform flexural vibration, thereby causing pressure changes in both of the first pump chamber and the second pump chamber. The first plate member is provided with first hole portions not overlapping an axial line orthogonal to a central region of the first plate member, and a check valve is provided to each of the first hole portions. The second plate member and the third plate member are provided with a second hole portion and a third hole portion respectively, and the check valve is provided to at least one of the second hole portion and the third hole portion.

A pump apparatus includes a piezoelectric pump, an outer housing, and an adhesive sheet. The piezoelectric pump has a principal surface at which a discharge port for a fluid is formed. The outer housing has a housing channel that communicates with the discharge port, and the outer housing is formed at least partially using a resin having water-containing properties. The adhesive sheet adheres the principal surface of the piezoelectric pump to the outer housing. The outer housing includes a main plate. The main plate has a principal surface that opposes the principal surface of the piezoelectric pump and is in contact with the adhesive sheet. The main plate also has a through-hole that communicate with the discharge port and with the housing channel. The principal surface is formed as a surface of a metal portion.

A pump includes a first pump chamber defined by a first plate-shaped body and a second plate-shaped body, a second pump chamber defined by the first plate-shaped body and a third plate-shaped body, and a driving body. The driving body causes a pressure fluctuation, by causing the first plate-shaped body to undergo bending vibration, in both the first pump chamber and the second pump chamber. The first plate-shaped body is provided with a plurality of first hole portions that does not overlap with an axis orthogonal to the central portion of the first plate-shaped body, and a check valve is attached to each of the plurality of first hole portions. The second plate-shaped body and the third plate-shaped body are respectively provided with second hole portions and third hole portions, and no check valve is attached to the second hole portions and the third hole portions.

A pump includes a first pump chamber defined by a first plate-shaped body and a second plate-shaped body, a second pump chamber defined by the first plate-shaped body and a third plate-shaped body, and a driving body. The driving body causes a pressure fluctuation, by causing the first plate-shaped body to undergo bending vibration, in both the first pump chamber and the second pump chamber. The first plate-shaped body is provided with a plurality of first hole portions that does not overlap with an axis orthogonal to the central portion of the first plate-shaped body, and a check valve is attached to each of the plurality of first hole portions. The second plate-shaped body and the third plate-shaped body are respectively provided with second hole portions and third hole portions, and no check valve is attached to the second hole portions and the third hole portions.

A pump includes a first diaphragm, a second diaphragm, and a circumferential wall, which define a pump chamber, and a driver. The driver vibrates the first diaphragm and the second diaphragm in a flexural mode to cause pressure fluctuation in the pump chamber. The first diaphragm has a first hole to which no check valve is attached. At least one of the first diaphragm and the second diaphragm has a second hole to which a check valve is attached. The first hole is located at a portion that coincides with an axis orthogonal to a center of the first diaphragm and a center of the second diaphragm. The second hole is located at a portion that does not coincide with the first hole when viewed in a direction in which the axis extends.

A dual pumping fluid pump which significantly reduces vibration and noise generation. When a cam installed on a rotating shaft of a single electric motor is rotated, a pair of first and second diaphragms installed in connection to an eccentric shaft portion formed on both the left and right sides of the cam alternatingly rise and descend in opposite directions and cause first and second intake check valves and first and second discharge check valves provided on a fluid passage box integrally and connectedly installed on the top surface of a pump housing to open or close first and second intake holes and first and second discharge holes to admit fluid through a fluid inlet and simultaneously discharge fluid through a fluid outlet, so that the simultaneous effects of the intake pressure and discharge pressure of fluid causes pressure balancing to occur.

A dual pumping fluid pump which significantly reduces vibration and noise generation. When a cam installed on a rotating shaft of a single electric motor is rotated, a pair of first and second diaphragms installed in connection to an eccentric shaft portion formed on both the left and right sides of the cam alternatingly rise and descend in opposite directions and cause first and second intake check valves and first and second discharge check valves provided on a fluid passage box integrally and connectedly installed on the top surface of a pump housing to open or close first and second intake holes and first and second discharge holes to admit fluid through a fluid inlet and simultaneously discharge fluid through a fluid outlet, so that the simultaneous effects of the intake pressure and discharge pressure of fluid causes pressure balancing to occur.