Pump and beverage supply device

Abstract

This pump is provided with: an electromagnet; a first movable plate and a second movable plate that are attracted to the electromagnet by a magnetic field generated by energization of the electromagnet; a first plate spring and a second plate spring to which the first movable plate and the second movable plate are attached, respectively, and which, in response to attraction operations of the first movable plate and the second movable plate toward the electromagnet, bias the first movable plate and the second movable plate in a direction opposite to the attraction operations; a flow path through which a fluid flows; a first pump chamber and a second pump chamber provided on the flow path; and a first piston and a second piston, serving as examples of volume changing members that operate to reduce or increase the volumes of the first pump chamber and the second pump chamber in accordance with the operations of the first movable plate and the second movable plate.

Description

Pumps and beverage dispensers

[0001] The present disclosure relates to a pump and a beverage dispensing device.

[0002] Solenoid-driven metering pumps are often used in beverage dispensers such as home espresso machines and inexpensive commercial espresso machines. A solenoid-driven metering pump is a pump powered by an electromagnet. When energized, the electromagnet attracts the pump shaft, creating a reciprocating motion of a diaphragm, which transfers a fixed amount of fluid (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2001-230115

[0004] Solenoid-driven metering pumps are powered by a solenoid and are therefore inefficient, consuming a lot of power and generating a lot of vibration.

[0005] The present disclosure aims to provide a pump and a beverage supply device that can achieve high efficiency.

[0006] A pump according to one aspect of an embodiment of the present invention includes an electromagnet, a movable plate that is attracted to the electromagnet by a magnetic field generated by energizing the electromagnet, a leaf spring to which the movable plate is attached and that biases the movable plate in a direction opposite to the attracting action of the movable plate to the electromagnet, a flow path through which a fluid flows, a pump chamber provided on the flow path, and an action to reduce the volume of the pump chamber in response to the attracting action of the movable plate, and when the electromagnet is switched to a non-energized state after the attracting action, the movable plate is biased by the biasing force of the leaf spring. The pump chamber is provided with a volume change member that operates to increase the volume of the pump chamber in response to the movement of the plate away from the electromagnet, an intake valve that is provided in the pump chamber upstream of the flow path and opens when the volume change member operates in the direction of increasing the volume of the pump chamber to draw the fluid from the upstream side of the flow path into the pump chamber, and a discharge valve that is provided in the pump chamber downstream of the flow path and opens when the volume change member operates in the direction of reducing the volume of the pump chamber to discharge the fluid from the pump chamber to the downstream side of the flow path.

[0007] According to the present disclosure, a highly efficient pump and beverage supply device can be provided.

[0008] 3 is an exploded perspective view of the resonant actuator; Schematic diagram of a cross-sectional shape along the symmetry axis CA of the pump according to the embodiment; Schematic diagram of a cross-sectional shape along the axial direction of a fourth flow path of the pump according to the embodiment; Schematic diagram showing the operation of the pump when the coil is energized; Schematic diagram showing the periphery of the first pump chamber in the state of FIG. 7; Schematic diagram showing the operation of the pump when the coil is switched to non-energized; Schematic diagram showing the periphery of the first pump chamber in the state of FIG. 9; 14A and 14B are schematic diagrams of the cross-sectional shape along the axis of symmetry CA of the pump according to the fourth modified example; FIG. 15A is a plan view of the internal structure of the pump housing as viewed from the Z-positive side; FIG. 16A is a diagram showing an example of the application of the pump according to the embodiment; FIG. 17A is a side view showing an example of the configuration of the cooling flow path and the heat absorption section shown in FIG. 14; FIG. 18A is a diagram showing the configuration of the flow path of the pump according to the second modified example; FIG. 19A is a diagram showing the configuration of the flow path of the pump according to the third modified example;

[0009] Hereinafter, embodiments will be described with reference to the accompanying drawings. To facilitate understanding of the description, the same components in the drawings will be denoted by the same reference numerals as much as possible, and duplicated descriptions will be omitted.

[0010] In the following description, the X, Y, and Z directions are perpendicular to one another. The X and Y directions are horizontal, and the Z direction is vertical. The X direction is the longitudinal direction of the housing 2 and the resonant actuator 6. The Y direction is the lateral direction of the housing 2 and the resonant actuator 6. For ease of explanation, the positive Z direction may also be referred to as the upper side, and the negative Z direction may also be referred to as the lower side.

[0011] [Configuration of Pump] The configuration of a pump 1 according to the embodiment will be described with reference to FIGS. 1 to 6. FIG.

[0012] 1 is a perspective view showing an example of the appearance of a pump 1 according to an embodiment. As shown in FIG. 1, the pump 1 includes a housing 2, an inlet 3, and an outlet 4.

[0013] The housing 2 houses elements related to the pump function, such as a flow path 5 and a resonant actuator 6, which will be described later. In the example of Fig. 1, the housing 2 has a pair of rectangular main surfaces 21 and 22, and is formed in the shape of a rectangular parallelepiped in which the dimension between the main surfaces 21 and 22 is relatively thin compared to the sides of the main surfaces.

[0014] The pair of principal surfaces 21, 22 are formed to have the same shape and are arranged opposite each other in the Z direction. The pair of principal surfaces 21, 22 are arranged such that the long sides of the rectangles face each other in the Y direction and the short sides face each other in the X direction. That is, the pair of principal surfaces 21, 22 are formed so as to be line-symmetric in the Y direction with respect to an axis of symmetry CA (see FIG. 2) that passes through the centers of the short sides in the Y direction and extends in the X direction, and are also formed so as to be line-symmetric in the X direction with respect to an axis of symmetry CB (see FIG. 2) that passes through the centers of the long sides in the X direction and extends in the Y direction. FIG. 1 illustrates a center line CO of the pump 1 that passes through the intersection of these two axes of symmetry CA, CB (i.e., the centers of the pair of principal surfaces 21, 22) and extends in the Z direction.

[0015] Four side surfaces 23 to 26 are provided between the pair of main surfaces 21, 22, connecting the four sides of each main surface. One pair of side surfaces 23, 24 of the four side surfaces are formed in the same rectangular shape and arranged opposite each other in the X direction, with their long sides connected to the short sides of the pair of main surfaces 21, 22. The other pair of side surfaces 25, 26 of the four side surfaces are formed in the same rectangular shape and arranged opposite each other in the Y direction, with their long sides connected to the long sides of the pair of main surfaces 21, 22.

[0016] The inlet 3 draws fluid into the housing 2. The outlet 4 discharges fluid pressurized by the pump function inside the housing 2. In the example of FIG. 1 , the inlet 3 is provided on the Y negative side of the side surface 23 of the housing 2, and the outlet 4 is provided on the Y positive side of the side surface 24. The inlet 3 and the outlet 4 are both connected in the X direction and are arranged so that the direction of fluid intake from the inlet 3 into the housing 2 and the direction of fluid discharge from the housing 2 to the outlet 4 are the same. The inlet 3 and the outlet 4 are also arranged so that they are point-symmetrical with respect to the center line CO of the pump 1 when viewed from the Z direction.

[0017] FIG. 2 is a schematic diagram showing the general configuration inside the housing 2 of the pump 1 shown in FIG. 1 . FIG. 2 is a plan view of the pump 1 as viewed from the positive Z direction. In FIG. 2 , the internal structure of the housing 2 is schematically illustrated, and the outer shape of the housing 2 (i.e., the four side surfaces 23 to 26) is illustrated by two-dot chain lines. Also, in FIG. 2 , an axis of symmetry CA that passes through the center of the main surfaces 21 and 22 of the housing 2 in the Y direction and extends in the X direction, and an axis of symmetry CB that passes through the center of the X direction and extends in the Y direction, are illustrated by dashed dot chain lines. In FIG. 2 , the intersection of the axis of symmetry CA and the axis of symmetry CB is illustrated as a center line CO.

[0018] 2 , the pump 1 includes a flow path 5 inside the housing 2, which connects the intake port 3 and the exhaust port 4. The flow path 5 includes a first flow path 51, a second flow path 52, a third flow path 53, a fourth flow path 54, a fifth flow path 55, a sixth flow path 56, a seventh flow path 57, and an eighth flow path 58.

[0019] The first flow path 51 has its upstream end connected to the downstream end of the suction port 3 and is arranged to extend in the X-positive direction. The second flow path 52 and the third flow path 53 have their upstream ends both connected to the downstream end of the first flow path 51, branch off, and are arranged to extend in the X-negative and X-positive directions, respectively. The fourth flow path 54 has its upstream end connected to the downstream end of the second flow path 52 and is arranged to extend in the Y-positive direction. The fifth flow path 55 has its upstream end connected to the downstream end of the third flow path 53 and is arranged to extend in the Y-positive direction. The sixth flow path 56 has its upstream end connected to the downstream end of the fourth flow path 54 and is arranged to extend in the X-positive direction, and the seventh flow path 57 has its upstream end connected to the downstream end of the fifth flow path 55 and is arranged to extend in the X-negative direction, with the sixth flow path 56 and the seventh flow path 57 joining at their downstream ends. The eighth flow path 58 has its upstream end connected to the confluence of the sixth flow path 56 and the seventh flow path 57, extends in the positive X direction, and is disposed so that its downstream end is connected to the upstream end of the outlet 4. Note that in Figure 2, the flow direction of the fluid flowing through the suction port 3, the flow path 5, and the outlet 4 is indicated by arrows.

[0020] 1 , the inlet 3 and the outlet 4 are arranged so as to be point-symmetrical when viewed from the Z direction with respect to the center line CO of the pump 1. Therefore, it is preferable that the overall shape of the flow path 5 is also arranged so as to be point-symmetrical when viewed from the Z direction with respect to the center line CO of the pump 1. This makes it easier for the fluid to flow from the inlet 3 to the outlet 4 through the flow path 5.

[0021] Also installed inside the housing 2 is a resonant actuator 6 serving as a drive source for the pump 1. The resonant actuator 6 has an electromagnet 61 and is a device that generates vibrational motion by switching the electromagnet 61 between energized and de-energized states. The resonant actuator 6 also places the movable part (a group of components including movable plates 62 and 63 and leaf springs 64 and 65, described below) serving as a vibration element into a resonant state by setting the frequency of the control signal (i.e., switching frequency) that switches the electromagnet 61 between energized and de-energized states to the same frequency as or close to the resonant frequency of the movable part. As a result, the resonant actuator 6 can efficiently vibrate the movable part by utilizing the resonance of the movable part in addition to the attraction of the movable part by the electromagnet 61 when the electromagnet 61 is energized.

[0022] 2, the resonant actuator 6 is arranged so that the X direction is the longitudinal direction and the Y direction is the lateral direction, and is located at the center when viewed in the Z direction. Similarly to the housing 2, the resonant actuator 6 is formed so as to be line-symmetric in the Y direction with respect to the axis of symmetry CA, and so as to be line-symmetric in the X direction with respect to the axis of symmetry CB. The electromagnet 61 is located at the center of the resonant actuator 6.

[0023] Furthermore, the fourth flow path 54 of the flow path 5 is disposed adjacent to the electromagnet 61 on the negative X side, and is disposed so as to penetrate the resonant actuator 6 in the Y direction. Similarly, the fifth flow path 55 of the flow path 5 is disposed adjacent to the electromagnet 61 on the positive X side, and is disposed so as to penetrate the resonant actuator 6 in the Y direction.

[0024] Furthermore, a first pump chamber 7 and a second pump chamber 8 are provided in the fourth flow path 54 and the fifth flow path 55, respectively, in portions that overlap with the resonant actuator 6 as viewed in the Z direction. The first pump chamber 7 and the second pump chamber 8 are elements that pressurize and send fluid from the upstream side to the downstream side of the flow path 5 in response to the vibration motion of the resonant actuator 6. The fluid in the flow path 5 can flow from the intake port 3 to the exhaust port 4 by the operation of the first pump chamber 7 and the second pump chamber 8. In the example of FIG. 2 , both the first pump chamber 7 and the second pump chamber 8 are arranged on the axis of symmetry CA of the housing 2 and the resonant actuator 6. As described above, in the example of FIG. 2 , the shape of the flow path 5 is arranged to be point-symmetric as viewed in the Z direction with respect to the central axis O that passes through the centers of the pair of main surfaces 21, 22 of the housing 2. As a result, the first pump chamber 7 and the second pump chamber 8 are each positioned at approximately the middle position on the flow path 5, so that the energy required to draw fluid into the first pump chamber 7 and the second pump chamber 8 and to discharge fluid from the first pump chamber 7 and the second pump chamber 8 can be made approximately the same.

[0025] The configuration of the resonant actuator 6 of the pump 1 according to this embodiment will be described with reference to Figures 3 and 4. Figure 3 is a perspective view showing a schematic configuration of the resonant actuator 6. Figure 4 is an exploded perspective view of the resonant actuator 6 shown in Figure 3. The perspective directions of Figures 3 and 4 are the same as those of Figure 1.

[0026] As shown in FIGS. 3 and 4, the resonant actuator 6 includes an electromagnet 61, a pair of movable plates 62 and 63, and a pair of leaf springs 64 and 65.

[0027] The electromagnet 61 is disposed at the center of the resonant actuator 6 in the Z direction. As shown in FIG. 4 , the electromagnet 61 has a core 611 and a coil 612. The core 611 has a winding portion 611A and a pair of widened portions 611B. The winding portion 611A is located at the center of the core 611 in the X direction and is formed to extend in the X direction. The winding portion 611A has a rectangular cross section along the YZ plane, and has an outer circumferential surface formed by four faces normal to the Y positive side, the Y negative side, the Z positive side, and the Z negative side. A coil 612 is wound around the outer circumferential surface of the winding portion 611A. The pair of widened portions 611B are formed at both ends of the winding portion 611A in the X direction, protruding on both sides in the Z direction relative to the winding portion. The widened portion 611B also has a rectangular cross section along the YZ plane, and has four faces whose normal directions are the positive Y, negative Y, positive Z, and negative Z. In other words, the widened portion 611B has upper and lower end faces that protrude by the same amount along the Y direction relative to the wound portion 611A.

[0028] The electromagnet 61 generates a magnetic field passing through the center of the coil 612 when a current flows through the conductor that forms the coil 612. The magnetic field generated by the coil 612 is further strengthened by the core 611.

[0029] The pair of movable plates 62, 63 are plate-shaped members made of a magnetic material, and include a first movable plate 62 and a second movable plate 63. The first movable plate 62 is disposed on the positive Z direction side of the electromagnet 61, and the second movable plate 63 is disposed on the negative Z direction side of the electromagnet 61. The first movable plate 62 and the second movable plate 63 are formed in the same shape and are disposed opposite each other in the Z direction.

[0030] Since the first movable plate 62 and the second movable plate 63 are made of magnetic material, they are attracted to the electromagnet 61 by the magnetic field generated by energizing the electromagnet 61. Furthermore, when the electromagnet 61 changes from an energized state to a de-energized state, the first movable plate 62 and the second movable plate 63 move in the direction opposite to the attracting action due to the biasing forces applied by the leaf springs 64 and 65 attached to them, respectively. In other words, the first movable plate 62 and the second movable plate 63 can perform an oscillating motion in the Z direction by switching the electromagnet 61 between energized and de-energized states.

[0031] As shown in FIG. 4 , the first movable plate 62 has a central portion 621 and a pair of end portions 622, 623. The central portion 621 is the center of the first movable plate 62 in the X direction, and is formed into a rectangular shape with its long sides facing each other in the Y direction and its short sides facing each other in the X direction when viewed in the Z direction. The shape of the central portion 621 is formed so as to cover the entire outer shape of the electromagnet 61 when viewed from the Z positive direction. The pair of end portions 622, 623 are provided by connecting to both ends of the central portion 621 in the X direction, i.e., the short sides of the rectangular shape. In the example of FIG. 4 , one end portion 622 is located on the negative X direction side of the central portion 621, and the other end portion 623 is located on the positive X direction side of the central portion 621. The Y direction dimension of the pair of end portions 622, 623 is the same as that of the central portion 621. The X direction dimension of the pair of end portions 622, 623 is approximately the same. Furthermore, the thickness dimension in the Z direction of the pair of end portions 622 and 623 is preferably formed to be thinner than that of the central portion 621, as exemplified in, for example, FIGS.

[0032] Pistons 71 and 81 are provided on the negative Z direction surfaces of the pair of end portions 622 and 623 of the first movable plate 62 so as to extend in the negative Z direction. The pistons 71 and 81 will be described later.

[0033] The second movable plate 63 has a central portion 631 and a pair of end portions 632, 633. The central portion 631 is the center of the second movable plate 63 in the X direction, and is formed into a rectangular shape with its long sides facing each other in the Y direction and its short sides facing each other in the X direction when viewed in the Z direction. The shape of the central portion 631 is formed so as to cover the entire outer shape of the electromagnet 61 when viewed from the negative Z direction. The pair of end portions 632, 633 are provided by connecting to both ends of the central portion 631 in the X direction, i.e., the short sides of the rectangular shape. In the example of FIG. 4 , one end portion 632 is located on the negative X direction side of the central portion 631, and the other end portion 633 is located on the positive X direction side of the central portion 631. The Y direction dimension of the pair of end portions 632, 633 is the same as that of the central portion 631. The X direction dimension of the pair of end portions 632, 633 is approximately the same. Furthermore, the thickness dimension in the Z direction of the pair of end portions 632, 633 is preferably formed to be thinner than that of the central portion 631, as exemplified in, for example, FIGS.

[0034] Pistons 72 and 82 are provided on the Z positive side surfaces of the pair of end portions 632 and 633 of the second movable plate 63 so as to extend in the Z positive direction. The pistons 72 and 82 will be described later.

[0035] The pair of leaf springs 64, 65 are elastic members that bias in the Z direction, and include a first leaf spring 64 and a second leaf spring 65. The first leaf spring 64 is disposed on the positive Z side of the first movable plate 62, and the first movable plate 62 is attached to the first leaf spring 64. The second leaf spring 65 is disposed on the negative Z side of the second movable plate 63, and the second movable plate 63 is attached to the first leaf spring 64. The first leaf spring 64 and the second leaf spring 65 have the same shape and are disposed opposite each other in the Z direction. That is, as shown in FIG. 3 , the first leaf spring 64 and the second leaf spring 65 form the outermost portions of the resonant actuator 6 in the Z direction. In response to the attraction of the first movable plate 62 to the electromagnet 61, the first leaf spring 64 biases the first movable plate 62 in the direction opposite to the attraction (positive Z direction). Similarly, the second leaf spring 65 biases the second movable plate 63 in the direction opposite to the attraction (negative Z direction) in response to the attraction of the second movable plate 63 to the electromagnet 61 .

[0036] 4 , the first leaf spring 64 has a central portion 641, a pair of fixed end portions 642, and a pair of flexible portions 643. The central portion 641 is the center portion of the first leaf spring 64 in the X direction, and is a flat portion having a constant width in the Y direction and outer edges on both sides in the Y direction extending along the X direction. The first movable plate 62 is attached to the central portion 641 of the first leaf spring 64, and thus the first movable plate 62 and the first movable plate 62 are installed to be movable together.

[0037] The pair of fixed ends 642 are disposed at both ends of the first leaf spring 64 in the X direction, and are flat plate-like portions formed so that the outer edges in the X direction both extend in the Y direction. The pair of fixed ends 642 of the first leaf spring 64 are fixed to a support 9 (see FIG. 5, etc.) which is an example of a fixed object installed inside the housing 2, thereby fixing both end portions in the X direction.

[0038] The pair of flexible portions 643 are portions that are disposed between a central portion 641 and a pair of fixed end portions 642 along the X direction of the first leaf spring 64. The pair of flexible portions 643 are elastically deformed and bent so as to change the relative positional relationship in the Z direction between the central portion 641, to which the first movable plate 62 is attached, and the pair of fixed end portions 642 that are fixed to the support body 9. The first leaf spring 64 can bias the first movable plate 62 attached to the central portion 641 by such elastic deformation of the pair of flexible portions 643.

[0039] 4 and other figures, the pair of flexible portions 643 are formed so that the width dimension perpendicular to the direction connecting the central portion 641 and the pair of fixed end portions 642 is relatively small so as to facilitate elastic deformation, and are curved in an S-shape when viewed in the Z direction. In order to make the amount of deflection in the Y direction more uniform, the S-shaped curved portions are arranged on both sides of the symmetry axis CA in the Y direction and are formed to be line-symmetrical with respect to the symmetry axis CA. Note that the curved portions may have a shape other than an S-shape.

[0040] 4 , the second leaf spring 65 has a central portion 651, a pair of fixed end portions 652, and a pair of flexible portions 653. The central portion 651 is the center portion of the second leaf spring 65 in the X direction, and is a flat portion having a constant width in the Y direction and outer edges on both sides in the Y direction extending along the X direction. The second movable plate 63 is attached to the central portion 651 of the second leaf spring 65, and the second movable plate 63 and the second movable plate 63 are thereby installed to be movable integrally therewith.

[0041] The pair of fixed ends 652 are disposed at both ends of the second leaf spring 65 in the X direction, and are flat plate-like portions formed so that the outer edges in the X direction both extend in the Y direction. The pair of fixed ends 652 of the second leaf spring 65 are fixed to a support 9 (see FIG. 5, etc.) which is an example of a fixed object installed inside the housing 2, thereby fixing both end portions in the X direction.

[0042] The pair of flexible portions 653 are portions that are disposed between a central portion 651 and a pair of fixed end portions 652 along the X direction of the second leaf spring 65. The pair of flexible portions 653 are elastically deformed and bent so as to change the relative positional relationship in the Z direction between the central portion 651, to which the second movable plate 63 is attached, and the pair of fixed end portions 652 that are fixed to the support body 9. The second leaf spring 65 can bias the second movable plate 63 attached to the central portion 651 by such elastic deformation of the pair of flexible portions 653.

[0043] 4 and other figures, the pair of flexible portions 653 are formed so that the width dimension perpendicular to the direction connecting the central portion 651 and the pair of fixed end portions 652 is relatively small so as to facilitate elastic deformation, and are curved in an S-shape when viewed in the Z direction. In addition, in order to make the amount of bending in the Y direction more uniform, the S-shaped curved portions are arranged on both sides of the symmetry axis CA in the Y direction and are formed to be line-symmetrical with respect to the symmetry axis CA. Note that the curved portions may have a shape other than an S-shape.

[0044] 4, each element of the resonant actuator 6 is arranged so that the center position of each outer shape when viewed in the Z direction coincides with the center line CO of the pump 1. This allows the center of gravity of the resonant actuator 6 to be located near the center line CO of the pump 1, allowing the resonant actuator 6 to operate in a well-balanced manner.

[0045] In this embodiment, the first and second leaf springs 64 and 65 are respectively configured such that the first and second movable plates 62 and 63 are attached at the central portions 641 and 651, but the first and second movable plates 62 and 63 may be attached at any position other than the central portions in the X direction of the first and second leaf springs 64 and 65. Furthermore, the first and second leaf springs 64 and 65 are respectively configured such that they are fixed to the support 9 at a pair of fixed ends 642 and 652, but they may be fixed to the support 9 at any position other than both ends in the X direction.

[0046] Furthermore, in this embodiment, as described above, the first movable plate 62 and the second movable plate 63 are formed to have the same shape, and the first leaf spring 64 and the second leaf spring 65 are formed to have the same shape. The attachment position of the first movable plate 62 to the first leaf spring 64 is also the same as the attachment position of the second movable plate 63 to the second leaf spring 65. Therefore, the resonant frequency of the first movable part (the first movable plate 62 and the first leaf spring 64) is also the same as the resonant frequency of the second movable part (the second movable plate 63 and the second leaf spring 65). Therefore, if the switching frequency of the single electromagnet 61 disposed between the first movable part and the second movable part, which switches between a conductive state and a non-conductive state, is set to the same frequency as or close to the resonant frequency common to the first movable part and the second movable part, both the first movable part and the second movable part can be brought into a resonant state together. This allows the resonant actuator 6 of this embodiment to vibrate the movable part more efficiently.

[0047] The configurations of the first pump chamber 7 and the second pump chamber 8 of the pump 1 according to this embodiment will be described with reference to Figures 5 and 6. Figure 5 is a schematic diagram of a cross-sectional shape of the pump 1 according to this embodiment taken along the axis of symmetry CA. Figure 5 does not show elements of the pump 1 that are outside the resonant actuator 6, including the housing 2.

[0048] As shown in FIG. 5 , the fourth flow path 54 and the fifth flow path 55 are holes provided in a support 9, which is an example of a fixed object installed inside the housing 2. The support 9 includes, for example, a block-shaped component fixed to the inner wall surface of the housing 2. The other flow paths of the flow path 5, other than the fourth flow path 54 and the fifth flow path 55, are also holes provided in the support 9. In the example of FIG. 5 , the support 9 on which the flow path 5 is provided and the support 9 to which the pair of fixed ends 642 of the first leaf spring 64 and the pair of fixed ends 652 of the second leaf spring 65 of the resonant actuator 6 are fixed are illustrated as an integrated component. However, separate components may be integrally connected to each other. Similarly, the first to eighth flow paths 51 to 58 constituting the flow path 5 may be provided in separate supports, and these supports may be connected to form the flow path 5.

[0049] 5 is a cross section taken along the axis of symmetry CA of the pump 1, and therefore, as is clear from reference to Fig. 2, it is a cross section of a portion of the fourth flow path 54 where the first pump chamber 7 is disposed, and a portion of the fifth flow path 55 where the second pump chamber 8 is disposed. As shown in Fig. 5, the first pump chamber 7 and the second pump chamber 8 are provided with cylinders 73 and 83, respectively, which communicate with each other along the Z direction.

[0050] The cylinder 73 of the first pump chamber 7 is formed to open on the Z positive side and the Z negative side of the support body 9. Furthermore, in this embodiment, the first piston 71 provided on the first movable plate 62 and the second piston 72 provided on the second movable plate 63 are disposed in positions where their axial directions overlap with the first pump chamber 7, i.e., positions where they overlap with the axial direction of the cylinder 73. Therefore, as shown in Fig. 5 , the first piston 71 is slidably inserted into the cylinder 73 from the opening on the Z positive side, and the second piston 72 is slidably inserted into the cylinder 73 from the opening on the Z negative side.

[0051] The cylinder 83 of the second pump chamber 8 is formed to open on the Z positive side and the Z negative side of the support body 9. Furthermore, in this embodiment, the first piston 81 provided on the first movable plate 62 and the second piston 82 provided on the second movable plate 63 are disposed in a position where their axial directions overlap with the second pump chamber 8, i.e., in a position where they overlap with the axial direction of the cylinder 83. For this reason, as shown in Fig. 5 , the first piston 81 is slidably inserted into the cylinder 83 from the opening on the Z positive side, and the second piston 82 is slidably inserted into the cylinder 83 from the opening on the Z negative side.

[0052] These first pistons 71, 81 and second pistons 72, 82 are respectively mounted on the first movable plate 62 and the second movable plate 63. Therefore, in conjunction with the vibration motion of the first movable plate 62 and the second movable plate 63 in the Z direction caused by energization control of the electromagnet 61, the first pistons 71, 81 and the second pistons 72, 82 slide within the respective cylinders 73, 83, repeatedly moving toward and away from each other. This allows the volumes of the first pump chamber 7 and the second pump chamber 8 to increase or decrease.

[0053] Fig. 6 is a schematic diagram of a cross-sectional shape of the fourth flow path 54 of the pump 1 according to the embodiment, taken along the axial direction. As shown in Fig. 6, an inlet valve 74 and a discharge valve 75 are provided upstream and downstream of the first pump chamber 7 in the fourth flow path 54, respectively. When the first piston 71 and the second piston 72 approach each other in the cylinder 73 and the volume of the first pump chamber 7 decreases, the inlet valve 74 closes to prevent fluid from flowing into the first pump chamber 7 from the upstream side of the fourth flow path 54, and the discharge valve 75 opens to discharge fluid from the first pump chamber 7 to the downstream side of the fourth flow path 54. On the other hand, when the first piston 71 and the second piston 72 move away from each other in the cylinder 73 and the volume of the first pump chamber 7 increases, the inlet valve 74 opens to allow fluid to flow into the first pump chamber 7 from the upstream side of the fourth flow path 54, and the discharge valve 75 closes to prevent fluid from being discharged from the first pump chamber 7 to the downstream side of the fourth flow path 54.

[0054] 6 illustrates a configuration for achieving this effect in which both the suction valve 74 and the discharge valve 75 have a sphere disposed upstream of the fourth flow path 54 so as to be able to seal the flow path, and a spring disposed downstream for biasing the sphere upstream. However, the suction valve 74 and the discharge valve 75 may have a configuration other than that shown in FIG. 6.

[0055] In this embodiment, the volume of the region between the lower end surface of the first piston 71 and the upper end surface of the second piston 72 in the cylinder 73 is the volume of the first pump chamber 7. This volume increases or decreases in accordance with the up and down movement of the first piston 71 and the second piston 72 in the cylinder 73.

[0056] 6 illustrates the cross section of the fourth flow path 54 to explain the configuration of the first pump chamber 7, but the second pump chamber 8 in the fifth flow path 55 has a similar configuration. That is, the area between the lower end surface of the first piston 81 and the upper end surface of the second piston 82 in the cylinder 83 defines the volume of the second pump chamber 8. This volume increases or decreases in accordance with the up and down movement of the first piston 81 and the second piston 82 in the cylinder 83.

[0057] [Operation of Pump] The operation of the pump 1 according to the embodiment will be described with reference to FIGS.

[0058] Fig. 7 is a schematic diagram showing the operation of the pump 1 when the coil is energized. Fig. 8 is a schematic diagram showing the periphery of the first pump chamber 7 in the state shown in Fig. 7. The outlines of Figs. 7 and 8 are similar to those of Figs. 5 and 6.

[0059] As shown in Fig. 7, when the coil 612 of the electromagnet 61 is energized, a magnetic field M1 is generated that passes through the center of the coil 612. The magnetic field M1 generated by the coil 612 is further strengthened by the winding portion 611A of the core 611 that is installed to pass through the center of the coil 612. In the example of Fig. 7, the magnetic field M1 is generated inside the winding portion 611A toward the positive X direction.

[0060] The magnetic field M1 thus generated branches into the Z-positive and Z-negative directions along the protruding direction of one of the widened portions 611B, which is disposed on the X-positive side of the winding portion 611A of the core 611. Next, the magnetic field M1 flows toward the X-negative direction through the first movable plate 62 and the second movable plate 63, which are disposed opposite the upper and lower end faces of the widened portion 611B, respectively. Then, the magnetic field M1 flows from the upper and lower end faces of the other widened portion 611B, which is disposed on the X-negative side of the winding portion 611A, toward the center of the widened portion 611B in the Z direction, merges, and then flows back into the winding portion 611A. In other words, the magnetic field M1 illustrated in FIG. 7 flows clockwise on the first movable plate 62 side and counterclockwise on the second movable plate 63 side when viewed from the Y-negative side.

[0061] 7, the first movable plate 62 is attracted to the electromagnet 61 and moves in the negative Z direction, as shown by arrow A. Similarly, the second movable plate 63 is attracted to the electromagnet 61 and moves in the positive Z direction, as shown by arrow B.

[0062] As a result of this movement of the first movable plate 62 and the second movable plate 63 toward the side where they are attracted to the electromagnet 61, in the first pump chamber 7, the first piston 71 slides in the negative Z direction within the cylinder 73 as indicated by arrow C. Also, the second piston 72 slides in the positive Z direction within the cylinder 73 as indicated by arrow D. As a result, the lower end surface of the first piston 71 and the upper end surface of the second piston 72 approach each other, and the volume of the first pump chamber 7 decreases.

[0063] Similarly, in the second pump chamber 8, the first piston 81 slides in the negative Z direction within the cylinder 83 as indicated by arrow E. Also, the second piston 82 slides in the positive Z direction within the cylinder 83 as indicated by arrow F. As a result, the lower end surface of the first piston 81 and the upper end surface of the second piston 82 approach each other, and the volume of the second pump chamber 8 decreases.

[0064] Ideally, the first movable plate 62 and the second movable plate 63 are both moved parallel to the Z direction by the magnetic field M1. Therefore, the sliding distance of the two first pistons 71, 81 installed on the first movable plate 62 is the same as the sliding distance of the two second pistons 72, 82 installed on the second movable plate 63. Therefore, the reduction amounts of the volumes of the first pump chamber 7 and the second pump chamber 8 are also the same.

[0065] Furthermore, as the first movable plate 62 moves toward the side where it is attracted to the electromagnet 61, the central portion 641 of the first leaf spring 64 to which the first movable plate 62 is attached also moves integrally with the first movable plate 62 in the direction of arrow A. At this time, since the fixed end 642 of the first leaf spring 64 is fixed to the support 9, the central portion 641 is displaced in the negative Z direction relative to the fixed end 642. In FIG. 7 , the Z-direction position of the first leaf spring 64 in the steady state shown in FIG. 5 is indicated by a dotted line S1. As a result of this displacement, the flexible portion 643 disposed between the central portion 641 and the fixed end 642 is elastically deformed in the negative Z direction, which generates a biasing force f1 in the flexible portion 643 for elastically returning to the positive Z direction, as indicated by the dotted arrow f1 in FIG. 7 .

[0066] Similarly, as the second movable plate 63 moves toward the side where it is attracted to the electromagnet 61, the central portion 651 of the second leaf spring 65 to which the second movable plate 63 is attached also moves integrally with the second movable plate 63 in the direction of arrow B. At this time, because the fixed end 652 of the second leaf spring 65 is fixed to the support 9, the central portion 651 is displaced in the positive Z direction relative to the fixed end 652. In FIG. 7 , the Z-direction position of the second leaf spring 65 in the steady state shown in FIG. 5 is indicated by a dotted line S2. As a result of this displacement, the flexible portion 653 located between the central portion 651 and the fixed end 652 is elastically deformed in the positive Z direction, which generates a biasing force f2 in the flexible portion 653 for elastically returning to the negative Z direction, as indicated by the dotted arrow f2 in FIG. 7 .

[0067] When the first pistons 71, 81 and the second pistons 72, 82 move closer to each other as shown in Figure 7, the volumes of the first pump chamber 7 and the second pump chamber 8 decrease. As a result, as shown in Figure 8, in the first pump chamber 7, the spherical bodies of the suction valve 74 and the discharge valve 75 are pressed toward the upstream and downstream sides of the fourth flow path 54, respectively, by the fluid in the first pump chamber 7. At this time, the spherical body of the suction valve 74 blocks the upstream side of the fourth flow path 54, so the suction valve 74 is closed. On the other hand, the spherical body of the discharge valve 75 is movable downstream as shown by arrow G, so the discharge valve 75 is opened. As a result, the fluid in the first pump chamber 7 is pressurized and discharged to the downstream side of the fourth flow path 54.

[0068] As described above, the amount of reduction in the volume of the first pump chamber 7 and the second pump chamber 8 is the same, so in the second pump chamber 8, the fluid in the second pump chamber 8 is pressurized and discharged downstream of the fifth flow path 55, similar to the operation of the first pump chamber 7 shown in Figure 7.

[0069] Fig. 9 is a schematic diagram showing the operation of the pump 1 when the coil is switched from energized to de-energized as shown in Fig. 7. Fig. 10 is a schematic diagram showing the periphery of the first pump chamber 7 in the state shown in Fig. 9. The outlines of Figs. 9 and 10 are similar to those of Figs. 5 and 6.

[0070] As shown in FIG. 9, when the coil 612 of the electromagnet 61 is switched from the energized state shown in FIG. 7 to the de-energized state, the magnetic field M1 generated around the electromagnet 61 disappears.

[0071] When the magnetic field M1 disappears, the attractive force that the first movable plate 62 and the second movable plate 63 received from the electromagnet 61 also disappears. Therefore, the first leaf spring 64 operates to elastically return due to the biasing force f1 generated in the flexible portion 643 of the first leaf spring 64, as indicated by the dotted arrow in FIG. 7 , and the first movable plate 62 also moves in the positive Z direction in response to this operation. However, because the attractive force that was balanced with the biasing force f1 has disappeared, neither the first movable plate 62 nor the first leaf spring 64 remains stationary at the steady position S1, but rather moves further in the positive Z direction. Finally, as indicated by the arrow H in FIG. 9 , they move in the positive Z direction from the steady position S1 by an amount equivalent to the amount of movement due to the attraction of the electromagnet 61. Similarly, as shown by arrow I, the second movable plate 63 and the second leaf spring 65 also move in the negative Z direction from the steady position S2 due to the biasing force f2 in the negative Z direction that was generated in the flexible portion 653.

[0072] As a result of this movement of the first movable plate 62 and the second movable plate 63 away from the electromagnet 61, in the first pump chamber 7, the first piston 71 slides in the positive Z direction within the cylinder 73 as indicated by arrow J. Also, the second piston 72 slides in the negative Z direction within the cylinder 73 as indicated by arrow K. As a result, the lower end surface of the first piston 71 and the upper end surface of the second piston 72 move away from each other, and the volume of the first pump chamber 7 increases.

[0073] Similarly, in the second pump chamber 8, the first piston 81 slides in the cylinder 83 in the positive Z direction as indicated by arrow L. Also, the second piston 82 slides in the cylinder 83 in the negative Z direction as indicated by arrow M. As a result, the lower end surface of the first piston 81 and the upper end surface of the second piston 82 move away from each other, and the volume of the second pump chamber 8 increases.

[0074] Ideally, the first movable plate 62 and the second movable plate 63 both move parallel to the Z direction due to the biasing forces f1 and f2 of the flexible portions 643 and 653. Therefore, the sliding distance of the two first pistons 71 and 81 installed on the first movable plate 62 is the same as the sliding distance of the two second pistons 72 and 82 installed on the second movable plate 63. Therefore, the increase in volume of the first pump chamber 7 and the second pump chamber 8 is also the same.

[0075] 9 , when the first pistons 71, 81 and the second pistons 72, 82 move away from each other, the volumes of the first pump chamber 7 and the second pump chamber 8 increase. As a result, as shown in FIG. 10 , in the first pump chamber 7, the balls of the suction valve 74 and the discharge valve 75 are each sucked toward the cylinder 73 by the fluid in the first pump chamber 7. At this time, the ball of the discharge valve 75 moves to block the upstream side of the fourth flow path 54, as indicated by arrow N, so the discharge valve 75 is closed. Meanwhile, the ball of the suction valve 74 is able to move downstream, as indicated by arrow O, so the suction valve 74 is opened. As a result, the fluid upstream of the fourth flow path 54 is sucked into the first pump chamber 7.

[0076] As described above, the increase in volume of the first pump chamber 7 and the second pump chamber 8 is the same, so in the second pump chamber 8, the fluid upstream of the fifth flow path 55 is sucked into the second pump chamber 8, similar to the operation of the first pump chamber 7 shown in Figure 10.

[0077] In the pump 1 of this embodiment, the pump 1 can be driven by controlling the supply of electricity to the coil 612 of the electromagnet 61 so as to alternate between the state in which the coil is energized (first state) shown in Figures 7 and 8 and the state in which the coil is not energized (second state) shown in Figures 9 and 10.

[0078] With this control, the pressure of the fluid discharged from the pump 1 can be adjusted according to the amount and speed of movement of the first pistons 71, 81 and the second pistons 72, 82. To adjust the pressure, it is necessary to adjust the amount and speed of movement of the first movable plate 62 and the second movable plate 63 on which the first pistons 71, 81 and the second pistons 72, 82 are installed. To adjust the movement of the movable plates 62, 63, it is necessary to adjust the strength (magnetic flux density, etc.) of the magnetic field M1 generated by the electromagnet 61. To adjust the magnetic field M1, it is necessary to control the magnitude of the current flowing through the coil 612 of the electromagnet 61. In other words, with the pump 1 of this embodiment, it is possible to control the discharge of fluid at a desired pressure by controlling the value of the current flowing through the coil 612 of the resonant actuator 6.

[0079] Alternatively, in the pump 1 of this embodiment, it is also possible to control the discharge of fluid at a desired pressure by adjusting various structural elements, such as the number of turns of the wire of the coil 612 of the electromagnet 61, the X-direction and Y-direction dimensions of the wound portion 611A of the core 611, the Z-direction protrusion amount and X-direction and Y-direction dimensions of the widened portion 611B of the core 611, the area and shape of the first movable plate 62 and the second movable plate 63 as viewed in the Z direction, and the spring constants of the first leaf spring 64 and the second leaf spring 65.

[0080] The pump 1 of this embodiment includes an electromagnet 61, a first movable plate 62 and a second movable plate 63 that are attracted to the electromagnet 61 by a magnetic field M1 generated by energizing the electromagnet 61, a first leaf spring 64 and a second leaf spring 65 to which the first movable plate 62 and the second movable plate 63 are attached, and which urge the first movable plate 62 and the second movable plate 63 in a direction opposite to the suction action of the first movable plate 62 and the second movable plate 63 toward the electromagnet 61, a flow path 5 through which a fluid flows, a first pump chamber 7 and a second pump chamber 8 provided on the flow path 5, and which operate to reduce the volumes of the first pump chamber 7 and the second pump chamber 8 in response to the suction action of the first movable plate 62 and the second movable plate 63, and when the electromagnet 61 is switched to a non-energized state after the suction action, the urging forces of the first leaf spring 64 and the second leaf spring 65 urge the electromagnet 61 toward the first movable plate 62 and the second movable plate 63. 1, an intake valve 74 is provided upstream of the flow path 5 in the first pump chamber 7 and the second pump chamber 8, and opens when the first pistons 71, 81 and the second pistons 72, 82 operate in a direction to increase the volumes of the first pump chamber 7 and the second pump chamber 8, thereby drawing fluid from the upstream side of the flow path 5 into the first pump chamber 7 and the second pump chamber 8; and an exhaust valve 75 is provided downstream of the flow path 5 in the first pump chamber 7 and the second pump chamber 8, and opens when the first pistons 71, 81 and the second pistons 72, 82 operate in a direction to reduce the volumes of the first pump chamber 7 and the second pump chamber 8, thereby discharging fluid from the first pump chamber 7 and the second pump chamber 8 to the downstream side of the flow path 5.

[0081] Here, among the above-mentioned components, the electromagnet 61 can also be expressed as a “fixed part.” The first and second movable plates 62 and 63 and the first and second leaf springs 64 and 65 can also be expressed as a “movable part that performs a vibrating motion in which the movable plate 62 is attracted to the fixed part by a magnetic field generated when the electromagnet 61 is energized, and moves away from the fixed part by a biasing force generated when the electromagnet 61 is not energized.”

[0082] With this configuration, the fixed part (electromagnet 61) generates vibrations in the movable part (first movable plate 62, second movable plate 63, first leaf spring 64, and second leaf spring 65), causing the first piston 71 and the second piston 72 installed in the first pump chamber 7 to slide synchronously within the common cylinder 73. In other words, the resonant actuator 6 can be used as a drive source for the pump 1. This reduces the amount of piston movement required to increase or decrease the volume of the first pump chamber 7 and the second pump chamber 8 compared to conventional solenoid-driven metering pumps, thereby reducing vibration during operation of the pump 1. Furthermore, by setting the switching frequency for switching between the energized and de-energized states of the electromagnet 61 to the same frequency as or near the resonant frequency of the movable part, which is a vibrating element, the movable part can be placed in a resonant state. This allows the resonant actuator 6 to efficiently vibrate the movable part by utilizing the resonance of the movable part in addition to the attraction of the movable part by the electromagnet 61 when the electromagnet 61 is energized. As a result, the efficiency of the pump 1 of this embodiment can be improved.

[0083] In the pump 1 of this embodiment, the first movable plate 62 and the second movable plate 63 are disposed opposite each other with the electromagnet 61 interposed therebetween. The first movable plate 62 and the second movable plate 63 are attached to the first leaf spring 64 and the second leaf spring 65, respectively. That is, the first leaf spring 64 and the second leaf spring 65 are also disposed opposite each other with the electromagnet 61 interposed therebetween. The first pistons 71 and 81 are mounted on the first movable plate 62 and move in conjunction with the movement of the first movable plate 62. The second pistons 72 and 82 are mounted on the second movable plate 63 and move in conjunction with the movement of the second movable plate 63.

[0084] With this configuration, a pair of opposing movable parts (first movable plate 62 and first leaf spring 64, second movable plate 63 and second leaf spring 65) can be vibrated in synchronization with a single electromagnet 61. At this time, since the pair of movable parts are arranged opposite each other with the electromagnet 61 in between, the directions in which they are attracted by the electromagnet 61 are opposite. Therefore, the vibration directions of the pair of movable parts are out of phase. This makes it possible to cancel out the vibrations generated in the pump 1 by the operation of each movable part.

[0085] In addition, in the pump 1 of this embodiment, the first movable part (first movable plate 62 and first leaf spring 64) and the second movable part (second movable plate 63 and second leaf spring 65) are arranged opposite each other with the fixed part (electromagnet 61) in between. The first pistons 71, 81 are linked to the operation of the first movable part, and the second pistons 72, 82 are linked to the operation of the second movable part. The first piston 71 and the second piston 72 are installed in the same first pump chamber 7. Similarly, the first piston 81 and the second piston 82 are installed in the same second pump chamber 8.

[0086] With this configuration, a common pump chamber can be used for the pair of pistons, so only one flow path (fourth flow path 54) and one valve (suction valve 74, discharge valve 75) are required for each pair of first piston 71 and second piston 72. Similarly, only one flow path (fifth flow path 55) and one valve (suction valve 74, discharge valve 75) are required for each pair of first piston 81 and second piston 82. This reduces the number of parts and simplifies the structure of pump 1. Furthermore, because the pump chamber is common, the reaction force acting on the pair of pistons installed in this pump chamber is the same, and the misalignment between the movements of the pair of moving parts arranged opposite each other is reduced. This allows the number of pump chambers to be increased while reducing the number of parts, thereby improving pump efficiency.

[0087] Here, the effect of the core 611 of the electromagnet 61 according to this embodiment will be described with reference to Fig. 11 in addition to Fig. 7. Fig. 11 is a schematic diagram showing a magnetic field M2 generated in the electromagnet 61A using a flat core 611C as a comparative example.

[0088] In the comparative example shown in Fig. 11, the electromagnet 61A has a flat core 611C. The core 611C of the comparative example differs from the core 611 of the embodiment in that it does not have the widened portion 611B shown in Fig. 7 and other figures. The core 611C is formed so that the Z-direction dimension is uniform throughout the entire X-direction. In other words, the core 611C has a shape in which the wound portion 611A of the core 611 of the embodiment extends to the range on both sides of the X-direction where the widened portion 611B is located.

[0089] 11 , when a magnetic field M2 directed in the X-positive direction inside the core 611C is generated by energizing the coil 612, this magnetic field M2 first advances in the X-positive direction from the X-positive end of the core 611C into the space of the resonant actuator 6. Then, it branches off toward the Z-positive and Z-negative sides, curves, reverses its direction, enters the interior from the X-positive ends of the first movable plate 62 and the second movable plate 63, and heads toward the X-negative side. Then, it advances again in the X-negative direction into the space of the resonant actuator 6 from the X-negative ends of the first movable plate 62 and the second movable plate 63, curves toward the Z-negative and Z-positive sides, reverses its direction to the X-positive side, and merges with the magnetic field M2 before flowing into the X-negative end of the core 611C.

[0090] 11 is the same as the magnetic field M1 of the embodiment shown in Fig. 7 in that, when viewed from the negative Y direction, the magnetic field M2 of the comparative example flows clockwise on the first movable plate 62 side and counterclockwise on the second movable plate 63 side. However, the magnetic field M2 of the comparative example flows in a larger proportion within the space of the resonant actuator 6 than the magnetic field M1 of the embodiment, that is, the air gap is larger, and therefore the magnetic resistance tends to increase.

[0091] In contrast to this, in the electromagnet 61 of this embodiment, by providing the widened portion 611B in the core 611, as shown in Fig. 7, the air gap in the magnetic field M1 can be limited to the gap between the upper end surface of the widened portion 611B and the first movable plate 62, and the gap between the lower end surface of the widened portion 611B and the second movable plate 63. This reduces the air gap in the magnetic field M1 and reduces the magnetic resistance, making it possible to generate magnetic force more efficiently than in the comparative example.

[0092] In this embodiment, the core 611 of the electromagnet 61 is formed by stacking multiple electromagnetic steel plates in the Y direction, as shown in Figures 3 and 4. Adjacent electromagnetic steel plates are bonded together with an adhesive, and this adhesive portion forms an air gap, which creates magnetic resistance that makes it difficult for magnetic flux to flow. Since the magnetic flux generated by the coil 612 flows through the core 611 toward the movable plates 62 and 63, if the stacking direction is the Y direction as in this embodiment, the air gap is positioned parallel to the flow of magnetic flux, which results in less obstruction to the flow of magnetic flux and improved energy transmission efficiency.

[0093] On the other hand, in a configuration in which the lamination direction is different by 90 degrees from that of this embodiment, that is, in which the lamination direction is the X direction, an air gap is placed in a position that obstructs the flow of magnetic flux, thereby reducing efficiency.

[0094] Next, the effects of the shapes of the movable plates 62, 63 and the leaf springs 64, 65 in this embodiment will be described with reference to Fig. 12. Fig. 12 is a plan view of the internal structure of the housing 2 of the pump 1 as viewed from the Z positive side. Fig. 12 illustrates the interior of the housing 2 as viewed from the first leaf spring 64 side, with the main surface of the housing 2 on the Z positive side removed from the pump 1 shown in Fig. 1.

[0095] If the direction (Y direction) perpendicular to the direction (X direction) of the magnetic field M1 generated by the electromagnet 61 is defined as the width direction, as shown in Fig. 12, the width dimension W1 of at least the flexible portion 643 of the first leaf spring 64 is larger than the width dimension W2 of the first movable plate 62. The same applies to the relationship between the second movable plate 63 and the second leaf spring 65, which are hidden at the back of Fig. 12, and the width dimension W1 of at least the flexible portion 653 of the second leaf spring 65 is larger than the width dimension W2 of the second movable plate 63.

[0096] As described with reference to FIG. 7 , when the electromagnet 61 is energized during operation of the resonant actuator 6, the first movable plate 62 and the second movable plate 63 ideally move parallel to each other in a direction (Z direction) toward the electromagnet 61 due to the magnetic field M1 generated by the electromagnet 61. However, if the magnetic field M1 has an uneven magnetic flux density across the width of the movable plates 62 and 63, the first movable plate 62 and the second movable plate 63 may be twisted during operation, such as tilting in the X direction or the Y direction. Therefore, by forming the width W1 of the leaf springs 64 and 65 larger than that of the movable plates 62 and 63 as in this embodiment, the leaf springs 64 and 65 can more easily absorb the twisting of the movable plates 62 and 63 during operation, thereby enabling more stable translation of the first movable plate 62 and the second movable plate 63. As a result, the pump 1 of this embodiment, which uses the resonant actuator 6 as a drive source, can reduce noise and vibration.

[0097] Furthermore, the first pump chamber 7 and the second pump chamber 8 are disposed opposite each other at positions where a pair of first pistons 71, 81 are provided at both ends of the first movable plate 62 in the direction of the magnetic field M1 (X direction). Similarly, the second movable plate 63 is disposed opposite each other at positions where a pair of second pistons 72, 82 are provided at both ends of the second movable plate 63 in the direction of the magnetic field M1 (X direction). In this configuration having two pump chambers, two pistons are provided on one movable plate. Therefore, when the relationship between the widthwise dimension W1 of the leaf springs 64, 65 and the widthwise dimension W2 of the movable plates 62, 63 is satisfied, sliding of the two pistons provided on one movable plate relative to the pump chambers 7, 8 can be stabilized, thereby particularly suppressing twisting of the movable plates 62, 63.

[0098] Next, the effects of the arrangement of the first pump chamber 7 and the second pump chamber 8 will be described. As shown in Figures 2 and 7, the fourth flow path 54 including the first pump chamber 7 among the flow paths 5 of the pump 1 is arranged adjacent to a position opposite (on the negative X-direction side) the wound portion 611A of the core 611 of the electromagnet 61, across the widened portion 611B on the negative X-direction side of the core 611, and the flow direction is arranged along the width direction (Y direction). Similarly, the fifth flow path 55 including the second pump chamber 8 among the flow paths 5 of the pump 1 is arranged adjacent to a position opposite (on the positive X-direction side) the wound portion 611A of the core 611, across the widened portion 611B on the positive X-direction side of the core 611 of the electromagnet 61, and the flow direction is arranged along the width direction (Y direction).

[0099] Therefore, the first piston 71 inserted into the first pump chamber 7 is disposed adjacent to a position on the opposite side (X-negative direction side) of the wound portion 611A of the first movable plate 62, across the widened portion 611B on the X-negative direction side of the electromagnet 61. The second piston 72 also inserted into the first pump chamber 7 is disposed adjacent to a position on the opposite side (X-negative direction side) of the wound portion 611A of the second movable plate 63, across the widened portion 611B on the X-negative direction side of the electromagnet 61. Similarly, the first piston 81 inserted into the second pump chamber 8 is disposed adjacent to a position on the opposite side (X-positive direction side) of the wound portion 611A of the first movable plate 62, across the widened portion 611B on the X-positive direction side of the electromagnet 61. The second piston 82, which is also inserted into the second pump chamber 8, is positioned adjacent to the second movable plate 63 on the opposite side (X-positive side) of the winding portion 611A, sandwiching the widened portion 611B on the X-positive side of the electromagnet 61.

[0100] By providing the widened portions 611B at both ends in the X direction of the core 611 of the electromagnet 61, a magnetic field M1 is generated such that magnetic flux passes through the upper and lower end surfaces of the widened portion 611B in a concentrated manner, as shown in Fig. 7. In other words, when the electromagnet 61 is energized, the first movable plate 62 receives the strongest attractive force at a portion facing the upper end surface of the widened portion 611B, and the second movable plate 63 receives the strongest attractive force at a portion facing the lower end surface of the widened portion 611B. Therefore, by arranging the first pistons 71, 81 and the second pistons 72, 82 adjacent to the widened portion 611B, the first movable plate 62 and the second movable plate 63 can be arranged near the portions where the first movable plate 62 and the second movable plate 63 receive the strongest attractive force from the electromagnet 61. This makes it possible to efficiently apply external force in the sliding direction from the first movable plate 62 and the second movable plate 63 to the first pistons 71, 81 and the second pistons 72, 82, thereby improving the operating efficiency of both the first pump chamber 7 and the second pump chamber 8.

[0101] Furthermore, by arranging the first pistons 71, 81 and the second pistons 72, 82 near the portions of the first movable plate 62 and the second movable plate 63 that receive the strongest attractive force from the electromagnet 61, it is possible to prevent the movement directions of the first pistons 71, 81 and the second pistons 72, 82 from being twisted during the attraction operation due to the attractive force generated when the electromagnet 61 is energized. This makes it possible to align the movement directions of the first pistons 71, 81 and the second pistons 72, 82 with the axial directions (Z direction) of the cylinders 73, 83 of the respective pump chambers 7, 8, thereby further improving the operating efficiency of the first pump chamber 7 and the second pump chamber 8. As a result, the pump 1 of this embodiment can achieve improved performance and efficiency in a configuration that uses the resonant actuator 6 as a drive source.

[0102] Furthermore, the first pump chamber 7 is disposed adjacent to the core 611 of the electromagnet 61 on the opposite side (X-negative direction) of the wound portion 611A of the core 611, with one of the pair of widened portions 611B of the core 611 sandwiched therebetween, and the second pump chamber 8 is disposed adjacent to the core 611 on the opposite side (X-positive direction) of the wound portion 611A, with the other of the pair of widened portions 611B sandwiched therebetween. In this configuration having two pump chambers, two pistons are installed on one movable plate. Therefore, by arranging the pump chambers 7 and 8 adjacent to the widened portion 611B, it is possible to more easily equalize the external forces applied to the two pistons installed on one movable plate, and it is possible to more easily synchronize the sliding of the pistons in the pump chambers 7 and 8. This particularly improves the operating efficiency of the pump chambers.

[0103] As shown in FIG. 2 and other figures, it is preferable that both the first pump chamber 7 and the second pump chamber 8 are arranged on the axis of symmetry CA of the housing 2. As shown in FIG. 7 and other figures, the coil 612 of the electromagnet 61 is arranged so that its central axis coincides with the axis of symmetry CA, and therefore, magnetic flux tends to be most concentrated on the axis of symmetry CA near the center of the coil 612. Therefore, the first movable plate 62 and the second movable plate 63 are likely to receive the strongest attractive force from the electromagnet 61 on the axis of symmetry CA. Therefore, if the first pump chamber 7 and the second pump chamber 8 are arranged on the axis of symmetry CA, the first pistons 71, 81 and the second pistons 72, 82 are also arranged on the axis of symmetry CA. This makes it possible for the first movable plate 62 and the second movable plate 63 to efficiently apply an external force in the sliding direction to the first pistons 71, 81 and the second pistons 72, 82, thereby further improving the operating efficiency of the first pump chamber 7 and the second pump chamber 8.

[0104] [Application Example of Pump 1] Fig. 13 is a diagram showing an application example of the pump 1 according to the embodiment. As shown in Fig. 13, the pump 1 according to the present embodiment can be applied to a beverage supplying device such as an espresso machine 100, for example.

[0105] The espresso machine 100 includes a tank 101 , a heater 102 , a damper 103 , and a brewing unit 104 .

[0106] The tank 101 stores water used for espresso. The tank 101 and the pump 1, the pump 1 and the heater 102, and the heater 102 and the extraction unit 104 are connected by flow paths 107 that transport the water supplied from the tank 101.

[0107] The pump 1 pressurizes water delivered from the tank 101 and sends it to the heater 102. In the case of the espresso machine 100, the pump 1 preferably increases the pressure of the water to, for example, 9 atmospheres.

[0108] The heater 102 heats the pressurized water transported from the tank 101 and sends it to the extraction unit 104 .

[0109] Ground coffee beans 105 are packed in the lower part of the inside of the extraction unit 104 and are pressed downward by a damper 103. Hot water heated by a heater 102 and pressurized is supplied to the pressed coffee bean powder 105, and coffee is extracted from an extraction hole 106 at the bottom end of the extraction unit 104.

[0110] Espresso machines require the use of a high-pressure pump to extract coffee at high pressure. For this reason, conventional espresso machines often use a solenoid-driven metering pump. However, solenoid-driven metering pumps have problems such as high vibration and low efficiency.

[0111] In contrast, the pump 1 of this embodiment is configured to use a resonant actuator 6 as a drive source, which solves the problems of the conventional solenoid-driven metering pumps described above, and provides an espresso machine 100 that is more convenient to use.

[0112] The pump 1 can be applied to any beverage dispenser that requires pressure boosting, in addition to the espresso machine 100. Such a beverage dispenser may include at least a tank for storing a beverage, the pump 1 according to the embodiment for sucking the beverage from the tank and discharging it at a predetermined pressure, and a discharge unit (corresponding to the extraction unit 104 in the example of FIG. 13 ) for discharging the beverage discharged from the pump 1.

[0113] The pump 1 can also be used in any device other than a beverage supply device that requires pressure boosting, such as industrial manufacturing equipment (such as semiconductor manufacturing equipment), medical equipment, household equipment (such as toilets, washbasins, and baths), and agricultural equipment.

[0114] <First Modification> Fig. 14 is a diagram showing the configuration of a flow path 5A of a pump 1A according to a first modification. The outline of Fig. 14 corresponds to Fig. 2 , but the second flow path 52 and subsequent flow paths of the flow path 5A are shown by dotted lines, and the internal structure of the housing 2 on the Y positive side of the electromagnet 61 is not shown. Furthermore, for the electromagnet 61, which is shown as a rectangular outline only in Fig. 2, a core 611 and a coil 612 are shown.

[0115] The pump 1A according to the first modification is obtained by adding a coil cooling structure to the pump 1 according to the embodiment. The pump 1A according to the first modification has a cooling flow path 59 and a pair of heat absorption portions 11 and 12 as the coil cooling structure.

[0116] The cooling flow path 59 is provided by branching off from the flow path 5A. In the example of Fig. 14, the cooling flow path 59 is provided by branching off from the downstream end of the first flow path 51 of the flow path 5A, similar to the second flow path 52 and the third flow path 53. The cooling flow path 59 extends toward the Y positive direction and is provided so as to reach a position adjacent to the Y negative side of the coil 612 of the electromagnet 61. The tip of the cooling flow path 59 on the Y positive direction side is sealed. It is preferable that the tip of the cooling flow path 59 on the Y direction side be located approximately in the center of the coil 612 in the X direction.

[0117] Fig. 15 is a side view showing an example of the configuration of the cooling flow path 59 and the heat absorption sections 11 and 12 shown in Fig. 14. Fig. 15 is a cross-sectional view taken along the axial direction of the cooling flow path 59, and in addition to the cooling flow path 59, the heat absorption sections 11 and 12 and the winding section 611A of the core 611 are also shown in cross section.

[0118] As shown in FIG. 15, the cooling flow path 59 has a first hole 59A that opens to the positive Z direction and a second hole 59B that opens to the negative Z direction at its tip on the positive Y direction side.

[0119] The pair of heat absorption portions 11, 12 are plate members made of a conductor such as metal, and are formed to be able to make surface contact with the outer circumferential surface of the cooling flow path 59 and the outer circumferential surface of the coil 612. One of the heat absorption portions 11 is arranged to be in surface contact with the cooling flow path 59 and the coil 612 from the positive Z direction side. The heat absorption portion 11 is also installed to block the first hole 59A of the cooling flow path 59. The other heat absorption portion 12 is arranged to be in surface contact with the cooling flow path 59 and the coil 612 from the negative Z direction side. The heat absorption portion 12 is also installed to block the second hole 59B of the cooling flow path 59.

[0120] The fluid flowing through the cooling flow path 59 in the positive Y direction flows into the first hole 59A and the second hole 59B at the tip and comes into contact with the parts of the heat absorption portions 11 and 12 exposed to the first hole 59A and the second hole 59B.

[0121] The heat absorption portions 11 and 12 are cooled by contacting with the fluid through the first hole 59 A and the second hole 59 B. The heat absorption portions 11 and 12 also absorb heat generated by the conduction of the coil 612 from the contact portions with the coil 612, thereby absorbing heat from the coil 612.

[0122] In this way, in pump 1A according to the first modification, heat can be absorbed from coil 612 of electromagnet 61 using cooling flow path 59 and heat absorption sections 11 and 12, thereby suppressing a rise in temperature of coil 612. This makes it possible to suppress a decrease in pump performance due to a rise in temperature of coil 612, and therefore suppress a decrease in performance due to heat generation from the drive source of pump 1A.

[0123] The cooling flow path 59 is preferably provided by branching off from a part of the flow path 5A that is upstream of the first pump chamber 7 and the second pump chamber 8. This is because, upstream of the first pump chamber 7 and the second pump chamber 8, the fluid is in a state before being pressurized in the pump chambers, and therefore is not affected by temperature changes due to pressurization, and a stable cooling effect can be obtained.

[0124] 14 illustrates a configuration in which cooling flow path 59 is branched off from flow path 5A, but flow path 5A may be used as cooling flow path 59. In this case, first hole 59A and second hole 59B are provided at any position in flow path 5A, and heat absorption units 11 and 12 are installed at positions on flow path 5A where first hole 59A and second hole 59B are provided. In either case, cooling flow path 59 can be included in the expression "part of flow path 5A."

[0125] <Second Modification> Fig. 16 is a diagram showing the configuration of a flow path 5B of a pump 1B according to a second modification. The outline of Fig. 16 corresponds to Fig. 2 .

[0126] As shown in Fig. 16, the arrangement of the inlet 3 and the outlet 4 may be changed. In the example of Fig. 16, the inlet 3 is provided on the negative X-direction side of the side surface 25 of the housing 2, and the outlet 4 is provided on the positive X-direction side of the side surface 26. The inlet 3 and the outlet 4 are both connected in the Y direction. The upstream end of the first flow path 51 of the flow path 5B is connected to the inlet 3 at a substantially right angle. Similarly, the downstream end of the eighth flow path 58 of the flow path 5B is connected to the outlet 4 at a substantially right angle.

[0127] In addition to the example shown in FIG. 16, the intake port 3 and the exhaust port 4 may be disposed at any position on the housing 2, such as a configuration in which the intake port 3 and the exhaust port 4 are provided on a pair of main surfaces 21 and 22.

[0128] <Third Modification> Fig. 17 is a diagram showing the configuration of a flow path 5C of a pump 1C according to a third modification. The outline of Fig. 17 corresponds to Fig. 2 .

[0129] 17 , in the flow path 5C, the first pump chamber 7 and the second pump chamber 8 may be disposed at positions other than the axis of symmetry CA, as long as they are at least the fourth flow path 54 and the fifth flow path 55. For example, as shown in FIG. 17 , the first pump chamber 7 may be disposed upstream of the flow path 5C on the negative Y direction side of the axis of symmetry CA. Alternatively, as shown in FIG. 17 , the second pump chamber 8 may be disposed downstream of the flow path 5C on the positive Y direction side of the axis of symmetry CA.

[0130] Furthermore, if the Y-direction positions of the first pump chamber 7 and the second pump chamber 8 are the same, the suction force that the first movable plate 62 and the second movable plate 63 receive from the electromagnet 61 can be made equal, thereby making the pump performance of the first pump chamber 7 and the second pump chamber 8 uniform.

[0131] 18 is a schematic diagram of a cross section of a pump 1D according to a fourth modification taken along the axis of symmetry CA. The outline of FIG. 18 corresponds to FIG.

[0132] As shown in Fig. 18, a configuration in which only a single piston is installed in one pump chamber may also be used. In the example of Fig. 18, only a first piston 71 inserted into the first pump chamber 7 is installed on the first movable plate 62. Only a second piston 82 inserted into the second pump chamber 8 is installed on the second movable plate 63.

[0133] 18 , the cylinder 73A of the first pump chamber 7 is open only on the first movable plate 62 side, formed to allow the first piston 71 to be inserted therethrough, and is sealed and does not open on the second movable plate 63 side. The cylinder 83A of the second pump chamber 8 is open only on the second movable plate 63 side, formed to allow the second piston 82 to be inserted therethrough, and is sealed and does not open on the first movable plate 62 side.

[0134] Even in a configuration in which only a single piston is installed in one pump chamber as described above, if the lower end of the sliding range of the first piston 71 is extended beyond the axis of symmetry CA to near the lower end of the fourth flow path 54, and the upper end of the sliding range of the second piston 82 is extended beyond the axis of symmetry CA to near the upper end of the fifth flow path 55, as shown by the arrows in Figure 18, it is possible to achieve pump performance similar to that of the pump 1 of the embodiment.

[0135] <Fifth Modification> Fig. 19 is a diagram showing the configuration of a flow path 5E of a pump 1E according to a fifth modification. The outline of Fig. 19 corresponds to Fig. 2 .

[0136] 19 , a configuration in which only a single pump chamber 7A is provided in the flow path 5E may be adopted. In this case, the pump chamber 7A is preferably disposed on the axis of symmetry CA and the axis of symmetry CB, i.e., at the position of the center line CO of the housing 2. This makes it possible to more uniform the driving force applied from the first movable plate 62 to the first piston and the driving force applied from the second movable plate to the second piston, thereby making it possible to further stabilize the pump performance.

[0137] When the pump chamber 7A is arranged in this manner, the flow path 5E may be configured to include only the first flow path 51 connected to the suction port 3, the eighth flow path 58 connected to the discharge port 4, and an intermediate flow path 55A connecting the downstream end of the first flow path 51 and the upstream end of the eighth flow path 58. The intermediate flow path 55A is arranged to extend along the Y direction with the axis of symmetry CB as its axial direction. The intermediate flow path 55A may be installed so as to pass through, for example, the winding portion 611A of the core 611 of the electromagnet 61 or the coil 612 along the Y direction.

[0138] In addition, in the configuration of the flow path 5 shown in FIG. 2, only either the first pump chamber 7 or the second pump chamber 8 may be provided.

[0139] <Sixth Modification> Fig. 20 is a diagram showing the configuration of a flow path 5F of a pump 1F according to a sixth modification. The outline of Fig. 20 corresponds to Fig. 2.

[0140] As shown in Fig. 20 , the inlet 3 and the outlet 4 may be provided on the same side surface of the housing 2. In the example of Fig. 20 , in this configuration, the inlet 3 and the outlet 4 are both provided on a side surface 25 of the housing 2, with the inlet 3 located on the negative X-direction side of the side surface 25 and the outlet 4 located on the positive X-direction side of the side surface 25. The inlet 3 and the outlet 4 are both in communication in the Y direction.

[0141] 20 , the flow path 5F has a first flow path 91, a second flow path 92, a third flow path 93, and a fourth flow path 94. The first flow path 91 and the second flow path 92 are connected to the suction port 3 at their upstream ends. The first flow path 91 is arranged to extend in the Y positive direction. The second flow path 92 is arranged to extend in the X positive direction.

[0142] The third flow path 93 has an upstream end connected to the downstream end of the first flow path 91. The third flow path 93 is arranged to extend in the X positive direction. The fourth flow path 94 has an upstream end connected to the downstream end of the third flow path. The fourth flow path 94 is arranged to extend in the Y negative direction.

[0143] The second flow path 92 and the fourth flow path 94 are connected to the outlet 4 at their downstream ends.

[0144] 20 , the first to fourth flow paths 91 to 94 of the flow path 5F are arranged to surround the outer periphery of the electromagnet 61 of the resonant actuator 6 when viewed in the Z direction. The first flow path 91 and the fourth flow path 94 are arranged to extend along the short sides of the rectangular outer shape of the electromagnet 61. The second flow path 92 and the third flow path 93 are arranged to extend along the long sides of the rectangular outer shape of the electromagnet 61.

[0145] 20 , the first pump chamber 95 is disposed at a central position in the extension direction (X direction) of the third flow path 93, and the second pump chamber 96 is disposed at a central position in the extension direction (X direction) of the second flow path 92. That is, it is preferable that the first pump chamber 95 and the second pump chamber 96 are both disposed on a symmetry axis CB extending in the Y direction. In the example of FIG. 20 , since the first pump chamber 95 and the second pump chamber 96 are disposed in this manner, the first movable plate 62 and the second movable plate 63 of the resonant actuator 6 are formed so that their end faces on the Y-positive side in the width direction (Y direction) extend to a position further on the Y-positive side than the first pump chamber 95 and the third flow path 93, and their end faces on the Y-negative side extend to a position further on the Y-negative side than the second pump chamber 96 and the second flow path 92.

[0146] 21 is a diagram showing an example of a configuration in which the same coil cooling structure as in the first modified example is applied to a pump 1F according to the sixth modified example. The outline of FIG. 21 corresponds to FIG.

[0147] The pump 1F according to the sixth modification has a cooling flow path 97 and a heat absorption portion 13 as the coil cooling structure.

[0148] The cooling flow path 97 is provided by branching off from the flow path 5F. In the example of Fig. 21 , the cooling flow path 97 is provided by branching off to the X-positive side at a central position (on the axis of symmetry CA) in the extension direction (Y direction) of the first flow path 91. The cooling flow path 97 extends from the first flow path 91 toward the X-positive side and reaches a position adjacent to the X-negative side of the widened portion 611B on the X-negative side of the core 611 of the electromagnet 61. The tip end of the cooling flow path 97 on the X-positive side is sealed.

[0149] A hole 97A that opens toward the Z positive direction is provided at the tip of the cooling flow path 97 on the X positive direction side. The heat absorption portion 13 is a plate made of a conductor such as metal, and is formed to be able to make surface contact with the outer circumferential surface of the cooling flow path 97 and the outer circumferential surface of the widened portion 611B on the X negative direction side. The heat absorption portion 13 is arranged to be in surface contact with the cooling flow path 97 and the widened portion 611B from the Z positive direction side. The heat absorption portion 13 is also installed so as to close the hole 97A of the cooling flow path 97.

[0150] The fluid flowing in the X-positive direction through the cooling flow path 97 flows into the hole 97A at the tip and comes into contact with the portion of the heat absorption portion 13 exposed through the hole 97A. The heat absorption portion 13 is cooled by coming into contact with the fluid through the hole 97A. The heat absorption portion 13 also absorbs heat generated by energizing the coil 612 and transferred to the core 611 through the contact portion with the widened portion 611B, thereby indirectly absorbing heat from the coil 612.

[0151] 15, the coil cooling structure in the sixth modified example may also be configured such that a pair of heat absorption portions 13 are provided on both sides in the Z direction of the cooling flow path 97. In this case, one of the pair of heat absorption portions 13 is arranged so as to be in surface contact with the cooling flow path 97 and the widened portion 611B from the positive Z direction side, and the other is arranged so as to be in surface contact with the cooling flow path 97 and the widened portion 611B from the negative Z direction side.

[0152] In this way, in the configuration in which the coil cooling structure is applied to the pump 1F according to the sixth modification, heat can be absorbed from the widened portion 611B of the core 611 of the electromagnet 61 using the cooling flow path 97 and the heat absorption portion 13, and therefore a temperature rise in the coil 612 can be suppressed via the widened portion 611B. This makes it possible to suppress a decrease in pump performance due to a temperature rise in the coil 612, and therefore a performance decrease due to heat generation from the drive source of the pump 1F can be suppressed.

[0153] The cooling flow path 97 is preferably provided by branching off from a flow path 5F that is upstream of the first pump chamber 95 and the second pump chamber 96. This is because, upstream of the first pump chamber 95 and the second pump chamber 96, the fluid is in a state before being pressurized in the pump chambers, and therefore is not affected by temperature changes due to pressurization, and a stable cooling effect can be obtained.

[0154] 21 illustrates a configuration in which the cooling flow path 97 is branched off from the flow path 5F, but the flow path 5F may be used as the cooling flow path 97. In this case, a hole 97A is provided at an arbitrary position in the flow path 5F, and the heat absorption portion 13 is installed at the position on the flow path 5F where the hole 97A is provided. In either case, the cooling flow path 97 can be included in the expression "part of the flow path 5F."

[0155] 22 is a schematic diagram of a cross section of a pump 1G according to a seventh modification taken along the axis of symmetry CA. The outline of FIG. 22 corresponds to FIG.

[0156] As shown in Fig. 22, only one of the pair of movable parts may be provided. In the example of Fig. 22, only a first movable plate 62 and a first leaf spring 64 are provided.

[0157] 22 , the cylinder 73B of the first pump chamber 7 is open only on the first movable plate 62 side (Z positive direction side) to allow the first piston 71 to be inserted therethrough, and is sealed and does not open on the Z negative direction side. The cylinder 83A of the second pump chamber 8 is also open only on the first movable plate 62 side (Z positive direction side) to allow the first piston 81 to be inserted therethrough, and is sealed and does not open on the Z negative direction side.

[0158] Even in a configuration in which only a single piston is installed in one pump chamber as described above, if the lower end of the sliding range of the first piston 71 is extended beyond the axis of symmetry CA to near the lower end of the fourth flow path 54, and the lower end of the sliding range of the first piston 81 is extended beyond the axis of symmetry CA to near the lower end of the fifth flow path 55, as shown by the arrows in Figure 22, it is possible to achieve pump performance similar to that of the pump 1 of the embodiment.

[0159] The present embodiment has been described above with reference to specific examples. However, the present disclosure is not limited to these specific examples. Design modifications to these specific examples made by a person skilled in the art as appropriate are also included within the scope of the present disclosure as long as they comprise the features of the present disclosure. The elements of the above-described specific examples, as well as their arrangement, conditions, shape, etc., are not limited to those exemplified and can be modified as appropriate. The elements of the above-described specific examples can be combined in various ways as appropriate, as long as no technical contradictions arise.

[0160] In the above embodiment, the first pistons 71, 81 and the second pistons 72, 82 are used as an example of a volume change member that reduces the volume of the pump chambers 7, 8 in response to the attraction of the movable plates 62, 63 toward the electromagnet 61, and increases the volume of the pump chambers 7, 8 in response to the urging forces f1, f2 of the leaf springs 64, 65 that move the movable plates 62, 63 away from the electromagnet 61 when the electromagnet 61 is de-energized after the attraction. However, elements other than pistons may also be used. Examples of elements other than pistons that can be used as volume change members include a diaphragm and a bellows.

[0161] This international application claims priority to U.S. Provisional Application No. 63 / 522,141, filed June 21, 2023, the entire contents of which are hereby incorporated by reference into this international application.

[0162] 1, 1A, 1B, 1C, 1D, 1E, 1F Pump 5, 5A, 5B, 5C, 5E, 5F Flow path 6 Resonant actuator 61 Electromagnet (fixed portion) 611 Core 611A Winding portion 611B Pair of widened portions 612 Coil 62 First movable plate (movable portion) 63 Second movable plate (movable portion) 64 First leaf spring (movable portion) 641 Center portion 642 Pair of fixed ends 643 Flexure portion 65 Second leaf spring (movable portion) 651 Center portion 652 Pair of fixed ends 653 Flexure portion 7 First pump chamber 71 First piston (volume change member) 72 Second piston (volume change member) 74 Intake valve 75 Discharge valve 8 Second pump chamber 81 First piston (volume change member) 82 Second piston (volume changing member) 9 Support 59, 97 Cooling flow path 11, 12, 13 Heat absorption part 100 Espresso machine (beverage supply device) 101 Tank 104 Extraction unit (discharge part) W1 Width direction dimension of leaf spring W2 Width direction dimension of movable plate

Claims

a leaf spring to which the movable plate is attached and which urges the movable plate in a direction opposite to the attraction action of the electromagnet in response to the attraction action of the movable plate to the electromagnet; a flow path through which a fluid flows; a pump chamber provided on the flow path; a volume change member which operates to reduce the volume of the pump chamber in response to the attraction action of the movable plate, and which operates to increase the volume of the pump chamber in response to the moving action of the movable plate away from the electromagnet due to the urging force of the leaf spring when the electromagnet is switched to a non-energized state after the attraction action; an intake valve provided in the pump chamber on the upstream side of the flow path, which opens when the volume change member operates in a direction to increase the volume of the pump chamber and draws the fluid from the upstream side of the flow path into the pump chamber; and a discharge valve provided in the pump chamber on the downstream side of the flow path, which opens when the volume change member operates in a direction to reduce the volume of the pump chamber and discharges the fluid from the pump chamber to the downstream side of the flow path. A pump comprising:

2. The pump according to claim 1, wherein the volume-changing member is a piston mounted on the movable plate, and the piston is movable in the direction of the suction movement of the movable plate and in the direction of the separation movement of the movable plate.

3. The pump described in claim 1, wherein the movable plate has a first movable plate and a second movable plate arranged opposite each other with the electromagnet in between, the leaf spring has a first leaf spring and a second leaf spring to which the first movable plate and the second movable plate are respectively attached, and the volume changing member has a first volume changing member and a second volume changing member which move in conjunction with the operation of the first movable plate and the second movable plate.

4. The pump according to claim 1, wherein the electromagnet has a core and a coil wound around the core, and the core is formed by laminating a plurality of electromagnetic steel sheets in a width direction perpendicular to the direction of the magnetic field.

5. A beverage supply device comprising: a tank for storing a beverage; a pump as described in any one of claims 1 to 4 for sucking the beverage in the tank and discharging it at a predetermined pressure; and a discharge section for discharging the beverage discharged from the pump.