Pumps and beverage supply devices

Abstract

To provide a pump that can stabilize the flow rate characteristics of the discharged fluid. [Solution] The pump 1 includes an intake pressure gauge 14 and an exhaust pressure gauge 15 provided on the intake and exhaust sides of the flow path 5, and a control unit 16 that generates control commands to the electromagnet 61 of the resonant actuator 6 in accordance with the intake pressure P1 and exhaust pressure P2 detected by the intake pressure gauge 14 and the exhaust pressure gauge 15, and controls the pressure of the fluid discharged from the pump chambers 7 and 8.

Description

Technical Field

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

Background Art

[0002] For pumps used in beverage supply devices such as household espresso machines and inexpensive commercial espresso machines, pumps using an electromagnetic actuator as a drive source are often applied. An electromagnetic actuator is an actuator that operates using the magnetic force of an electromagnet (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When applying a pump using an electromagnetic actuator as a drive source to a beverage supply device or the like, it may be difficult to stabilize the flow rate characteristics of the fluid flowing in the device unless the pressure of the fluid discharged from the pump and the pressure of the fluid sucked into the pump are known.

[0005] An object of the present disclosure is to provide a pump and a beverage supply device capable of stabilizing the flow rate characteristics of the discharged fluid.

Means for Solving the Problems

[0006] A pump according to one aspect of an embodiment of the present invention comprises: a drive source; a fluid passage through which fluid flows; a pump chamber provided on the fluid passage; a volume changing member that operates to reduce or increase the volume of the pump chamber in accordance with the operation of the drive source; an intake valve provided on the upstream side of the fluid passage in the pump chamber, which opens when the volume changing member moves in the direction of increasing the volume of the pump chamber, and draws the fluid into the pump chamber from the upstream side of the fluid passage; a discharge valve provided on the downstream side of the fluid passage in the pump chamber, which opens when the volume changing member moves in the direction of decreasing the volume of the pump chamber, and discharges the fluid from the pump chamber to the downstream side of the fluid passage; a pressure detection unit provided on at least one of the intake side and the discharge side of the fluid passage; and a control unit that generates a control command to the drive source in accordance with the value detected by the pressure detection unit and controls the pressure of the fluid discharged from the pump chamber. [Effects of the Invention]

[0007] According to this disclosure, it is possible to provide a pump and a beverage supply device that can stabilize the flow rate characteristics of the discharged fluid. [Brief explanation of the drawing]

[0008] [Figure 1] Perspective view showing an example of the appearance of the pump according to the embodiment. [Figure 2] Schematic diagram showing the general internal configuration of the pump housing shown in Figure 1. [Figure 3] Perspective view showing the schematic configuration of the resonant actuator. [Figure 4] Figure 3 shows an exploded perspective view of the resonant actuator. [Figure 5] Schematic diagram of the cross-sectional shape of the pump according to the embodiment along the axis of symmetry CA [Figure 6] Schematic diagram of the cross-sectional shape along the axial direction of the fourth flow path of the pump according to the embodiment. [Figure 7] A schematic diagram showing the operation of the pump when the coil is energized. [Figure 8] Schematic diagram showing the area around the first pump room in the state shown in Figure 7. [Figure 9]Schematic diagram showing the operation of the pump when switched to non - energized coil [Figure 10] Schematic diagram showing the periphery of the first pump chamber in the state of FIG. 9 [Figure 11] Schematic diagram of the magnetic field generated in an electromagnet using a flat - plate core as a comparative example [Figure 12] Plan view of the internal structure of the pump housing viewed from the +Z direction side [Figure 13] Figure showing an application example of the pump according to the embodiment [Figure 14] Figure showing the configuration of the flow path of the pump according to the first modification [Figure 15] Side view showing a configuration example of the cooling flow path and the heat absorption part shown in FIG. 14 [Figure 16] Figure showing the configuration of the flow path of the pump according to the second modification [Figure 17] Figure showing the configuration of the flow path of the pump according to the third modification [Figure 18] Schematic diagram of the cross - sectional shape along the symmetry axis CA of the pump according to the fourth modification [Figure 19] Figure showing the configuration of the flow path of the pump according to the fifth modification [Figure 20] Figure showing the configuration of the flow path of the pump according to the sixth modification [Figure 21] Figure showing an example of a configuration in which a coil cooling structure is applied to the pump according to the sixth modification [Figure 22] Schematic diagram of the cross - sectional shape along the symmetry axis CA of the pump according to the seventh modification [Figure 23] Block diagram showing an example of the control system of the pump according to the embodiment and each modification [Figure 24] Figure showing the basic configuration of a diaphragm - type rotary pump as an example of a modification of the pump

Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments will be described with reference to the accompanying drawings. For ease of understanding of the description, the same components in each drawing are denoted by the same reference numerals as much as possible, and duplicate descriptions are omitted.

[0010] In the following explanation, the X, Y, and Z directions are perpendicular to each other. 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 short-span direction of the housing 2 and the resonant actuator 6. Also, for convenience of explanation, the positive Z direction may be referred to as the upper side, and the negative Z direction as the lower side.

[0011] [Pump configuration] The configuration of the pump 1 according to this embodiment will be described with reference to Figures 1 to 6.

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

[0013] The housing 2 incorporates elements related to the pump function, such as the flow path 5 and the resonant actuator 6, which will be described later. In the example shown in Figure 1, the housing 2 has a pair of rectangular main surfaces 21 and 22, and the dimensions between each main surface 21 and 22 form a rectangular parallelepiped shape that is relatively thin with respect to each side of the main surface.

[0014] A pair of main surfaces 21 and 22 are formed to the same shape and are arranged opposite each other in the Z direction. The pair of main surfaces 21 and 22 are arranged so 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 main surfaces 21 and 22 are formed to be symmetric in the Y direction with respect to a symmetry axis CA (see Figure 2) that passes through the center of the short side in the Y direction and extends in the X direction, and also symmetric in the X direction with respect to a symmetry axis CB (see Figure 2) that passes through the center of the long side in the X direction and extends in the Y direction. Figure 1 shows the center line CO of the pump 1 that passes through the intersection of these two symmetry axes CA and CB (i.e., the centers of the pair of main surfaces 21 and 22) and extends in the Z direction.

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

[0016] The intake port 3 draws fluid into the housing 2. The outlet port 4 discharges the fluid pressurized by the pump function inside the housing 2. In the example in Figure 1, the intake port 3 is located on the negative Y-direction side of the side 23 of the housing 2, and the outlet port 4 is located on the positive Y-direction side of the side 24. Both the intake port 3 and the outlet port 4 are in communication in the X-direction, and are positioned so that the direction of fluid intake from the intake port 3 into the housing 2 and the direction of fluid discharge from the housing 2 to the outlet port 4 are the same. Furthermore, the intake port 3 and the outlet port 4 are positioned so as to be point-symmetric when viewed from the Z-direction with respect to the center line CO of the pump 1.

[0017] Figure 2 is a schematic diagram showing the general internal configuration of the housing 2 of the pump 1 shown in Figure 1. Figure 2 is a plan view of the pump 1 as seen from the positive Z direction. In Figure 2, the internal structure of the housing 2 is schematically illustrated, and the external shape of the housing 2 (i.e., the four sides 23-26) is shown by dashed lines. In Figure 2, the axis of symmetry CA, which passes through the center in the Y direction of the main surfaces 21 and 22 of the housing 2 and extends in the X direction, and the axis of symmetry CB, which passes through the center in the X direction and extends in the Y direction, are shown by dashed lines. In Figure 2, the intersection of axis of symmetry CA and axis of symmetry CB is shown as the center line CO.

[0018] As shown in Figure 2, the pump 1 has a passage 5 inside the housing 2 that connects the inlet 3 and the outlet 4. The passage 5 has a first passage 51, a second passage 52, a third passage 53, a fourth passage 54, a fifth passage 55, a sixth passage 56, a seventh passage 57, and an eighth passage 58.

[0019] The first channel 51 is positioned so as to extend in the positive X direction, with its upstream end connected to the downstream end of the intake port 3. The second channel 52 and the third channel 53 branch off, with their upstream ends both connected to the downstream end of the first channel 51, and are positioned so as to extend in the negative X direction and the positive X direction, respectively. The fourth channel 54 is positioned so as to extend in the positive Y direction, with its upstream end connected to the downstream end of the second channel 52. The fifth channel 55 is positioned so as to extend in the positive Y direction, with its upstream end connected to the downstream end of the third channel 53. The sixth channel 56 extends in the positive X direction, with its upstream end connected to the downstream end of the fourth channel 54, and the seventh channel 57 extends in the negative X direction, with its upstream end connected to the downstream end of the fifth channel 55, and the six channels 56 and the seventh channel 57 merging at their downstream ends. The eighth channel 58 is positioned such that its upstream end is connected to the confluence of the sixth channel 56 and the seventh channel 57, extends in the positive X direction, and its downstream end is connected to the upstream end of the discharge port 4. In Figure 2, the flow direction of the fluid flowing inside the intake port 3, channel 5, and discharge port 4 is illustrated with arrows.

[0020] As explained with reference to Figure 1, the arrangement of the inlet 3 and outlet 4 is such that they are 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 in a similar way, so that it is point-symmetrical when viewed from the Z direction with respect to the center line CO of the pump 1. This makes it easier for fluid to flow from the inlet 3 to the outlet 4 through the flow path 5.

[0021] Furthermore, a resonant actuator 6 is installed inside the housing 2 as a drive source for the pump 1. The resonant actuator 6 has an electromagnet 61 and is a device that generates vibration motion by switching the electromagnet 61 on and off. The resonant actuator 6 also causes the movable parts to resonate by setting the frequency of the control signal that switches between on and off (i.e., the switching frequency) to be the same as, or near, the resonant frequency of, the movable parts (a group of components including movable plates 62, 63 and leaf springs 64, 65, etc., which will be described later), which are the vibration elements. As a result, when the electromagnet 61 is on, the resonant actuator 6 can efficiently vibrate the movable parts by utilizing the resonance of the movable parts in addition to the attraction of the movable parts by the electromagnet 61.

[0022] In the example shown in Figure 2, the resonant actuator 6 is positioned such that its longitudinal direction is in the X direction and its short direction is in the Y direction, and is located in the center when viewed in the Z direction. Furthermore, like the housing 2, the resonant actuator 6 is formed to be symmetrical in the Y direction with respect to the symmetry axis CA, and symmetrical in the X direction with respect to the symmetry axis CB. The electromagnet 61 is located in the center of the resonant actuator 6.

[0023] Furthermore, the fourth channel 54 of channel 5 is positioned adjacent to the X-negative side of the electromagnet 61 and is arranged to penetrate the resonant actuator 6 in the Y direction. Similarly, the fifth channel 55 of channel 5 is positioned adjacent to the X-positive side of the electromagnet 61 and is arranged 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 portions of the fourth flow path 54 and the fifth flow path 55 that overlap with the resonant actuator 6 in the Z-direction view, respectively. 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 conjunction with the vibrational motion of the resonant actuator 6. The fluid in the flow path 5 can flow from the inlet 3 to the outlet 4 by the operation of the first pump chamber 7 and the second pump chamber 8. In the example of Figure 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. Also, as described above, in the example of Figure 2, the shape of the flow path 5 is arranged to be point-symmetric in the Z-direction view with respect to the central axis O passing through the centers of the pair of main surfaces 21 and 22 of the housing 2. As a result, the first pump chamber 7 and the second pump chamber 8 are positioned approximately midway along the flow path 5, making it possible to make the energy required for the intake of fluid into the first pump chamber 7 and the second pump chamber 8 and the energy required for the discharge of fluid from the first pump chamber 7 and the second pump chamber 8 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 the 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 views in Figures 3 and 4 are the same as in Figure 1.

[0026] As shown in Figures 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 positioned in the center of the resonant actuator 6 in the Z direction. As shown in Figure 4, the electromagnet 61 has a core 611 and a coil 612. The core 611 has a winding portion 611A and a pair of widening portions 611B. The winding portion 611A is the central part of the core 611 in the X direction and extends in the X direction. The winding portion 611A has a rectangular cross-sectional shape along the YZ plane, and its outer circumferential surface is formed on four surfaces with the positive Y direction, negative Y direction, positive Z direction, and negative Z direction as normal directions. The coil 612 is wound around the outer circumferential surface of the winding portion 611A. The pair of widening portions 611B are formed at both ends of the winding portion 611A along 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-sectional shape along the YZ plane and has four surfaces with the positive Y direction, negative Y direction, positive Z direction, and negative Z direction as normal directions. In other words, the widened portion 611B has an upper end surface and a lower end surface that protrude by the same amount from the wound portion 611A along the Y direction.

[0028] The electromagnet 61 generates a magnetic field passing through the center of the coil 612 when an electric current flows through the wires that make up 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 and 63 are plate-shaped members formed from a magnetic material, and consist of a first movable plate 62 and a second movable plate 63. The first movable plate 62 is positioned on the positive Z side of the electromagnet 61, and the second movable plate 63 is positioned on the negative Z side of the electromagnet 61. The first movable plate 62 and the second movable plate 63 are formed to be the same shape and are positioned opposite each other in the Z direction.

[0030] Since the first movable plate 62 and the second movable plate 63 are magnetic materials, they are attracted to the electromagnet 61 by the magnetic field generated when the electromagnet 61 is energized. Furthermore, when the electromagnet 61 is switched from energized to de-energized, the first movable plate 62 and the second movable plate 63 move in the opposite direction to the attractive motion due to the biasing force added by the leaf springs 64 and 65 to which they are attached. In other words, the first movable plate 62 and the second movable plate 63 can perform vibrational motion in the Z direction by switching the energization of the electromagnet 61 between energization and de-energization.

[0031] As shown in Figure 4, the first movable plate 62 has a central portion 621 and a pair of ends 622 and 623. The central portion 621 is the central part of the first movable plate 62 in the X direction and is formed in 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 to cover the entire outer shape of the electromagnet 61 when viewed from the positive Z direction. The pair of ends 622 and 623 are provided connected to both ends of the central portion 621 along the X direction, i.e., the short sides of the rectangular shape described above. In the example in Figure 4, one end 622 is positioned on the negative X direction side of the central portion 621, and the other end 623 is positioned on the positive X direction side of the central portion 621. The dimensions of the pair of ends 622 and 623 in the Y direction are the same as those of the central portion 621. The dimensions of the pair of ends 622 and 623 in the X direction are approximately the same for both. Furthermore, it is preferable that the thickness dimension of the pair of ends 622 and 623 in the Z direction be formed to be thinner than the central portion 621, as illustrated in Figures 3 and 4.

[0032] A pair of pistons 71 and 81 are installed on the Z-negative side surfaces of the first movable plate 62, at the ends 622 and 623, respectively, extending in the Z-negative 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 ends 632 and 633. The central portion 631 is the central part of the second movable plate 63 in the X direction and is formed in 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 to cover the entire outer shape of the electromagnet 61 when viewed from the negative Z direction side. The pair of ends 632 and 633 are provided connected to both ends of the central portion 631 along the X direction, i.e., the short sides of the rectangular shape described above. In the example in Figure 4, one end 632 is positioned on the negative X direction side of the central portion 621, and the other end 633 is positioned on the positive X direction side of the central portion 631. The dimensions of the pair of ends 632 and 633 in the Y direction are the same as those of the central portion 631. The dimensions of the pair of ends 632 and 633 in the X direction are approximately the same for both. Furthermore, it is preferable that the thickness dimension of the pair of end portions 632 and 633 in the Z direction be formed to be thinner than the central portion 631, as illustrated in Figures 3 and 4.

[0034] A pair of pistons 72 and 82 are installed on the Z-positive side of the respective Z-positive surfaces of the second movable plate 63, at the ends 632 and 633, respectively, extending in the Z-positive direction. The pistons 72 and 82 will be described later.

[0035] The pair of leaf springs 64 and 65 are elastic members that bias in the Z direction, and consist of a first leaf spring 64 and a second leaf spring 65. The first leaf spring 64 is positioned on the positive Z side of the first movable plate 62, and the first movable plate 62 is attached to it. The second leaf spring 65 is positioned on the negative Z side of the second movable plate 63, and the second movable plate 63 is attached to it. The first leaf spring 64 and the second leaf spring 65 are formed in the same shape and are positioned opposite each other in the Z direction. In other words, as shown in Figure 3, the first leaf spring 64 and the second leaf spring 65 form the outermost part of the resonant actuator 6 in the Z direction. The first leaf spring 64 biases the first movable plate 62 in the opposite direction (positive Z side) to the attractive movement of the first movable plate 62 to the electromagnet 61. Similarly, the second leaf spring 65 biases the second movable plate 63 in the opposite direction (negative Z direction) to the attraction movement of the second movable plate 63 to the electromagnet 61.

[0036] As shown in Figure 4, the first leaf spring 64 has a central portion 641, a pair of fixed ends 642, and a pair of flexible portions 643. The central portion 641 is the central part of the first leaf spring 64 in the X direction, and is a flat plate-shaped portion formed such that its width dimension in the Y direction is constant and its outer edges on both sides in the Y direction extend along the X direction. The first leaf spring 64 is installed so as to be movable integrally with the first movable plate 62 by attaching the first movable plate 62 to the central portion 641.

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

[0038] The pair of flexible portions 643 are located between the central portion 641 and the pair of fixed ends 642 of the first leaf spring 64, along the X direction. The pair of flexible portions 643 elastically deform and bend so that 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 ends 642 fixed to the support 9 changes. The first leaf spring 64 can bias the first movable plate 62 attached to the central portion 641 by the elastic deformation of this pair of flexible portions 643.

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

[0040] As shown in Figure 4, the second leaf spring 65 has a central portion 651, a pair of fixed ends 652, and a pair of flexible portions 653. The central portion 651 is the central part of the second leaf spring 65 in the X direction, and is a flat plate-shaped portion formed such that its width dimension in the Y direction is constant and its outer edges on both sides in the Y direction extend along the X direction. The second leaf spring 65 is installed so that it can move integrally with the second movable plate 63 by attaching the second movable plate 63 to the central portion 651.

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

[0042] The pair of flexible portions 653 are located between the central portion 651 and the pair of fixed ends 652 of the second leaf spring 65, along the X direction. The pair of flexible portions 653 elastically deform and bend so that 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 ends 652 fixed to the support 9 changes. The second leaf spring 65 can bias the second movable plate 63 attached to the central portion 651 by the elastic deformation of this pair of flexible portions 653.

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

[0044] Furthermore, as shown in Figure 4, each element of the resonant actuator 6 is positioned such that the center of its outer shape in the Z-direction view 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, enabling the resonant actuator 6 to operate in a well-balanced manner.

[0045] In this embodiment, the first leaf spring 64 and the second leaf spring 65 are shown as having a configuration in which the first movable plate 62 and the second movable plate 63 are attached at their central portions 641 and 651, respectively. However, the first movable plate 62 and the second movable plate 63 may be attached at any position other than the central portion in the X direction of the first leaf spring 64 and the second leaf spring 65, respectively. Also, the first leaf spring 64 and the second leaf spring 65 are shown as being fixed to the support 9 at a pair of fixed ends 642 and 652, respectively. However, 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 with the same shape, and the first leaf spring 64 and the second leaf spring 65 are formed with the same shape. The mounting position of the first movable plate 62 to the first leaf spring 64 and the mounting position of the second movable plate 63 to the second leaf spring 65 are also the same. Therefore, the resonant frequency of the first movable part (the first movable plate 62 and the first leaf spring 64) and the resonant frequency of the second movable part (the second movable plate 63 and the second leaf spring 65) are the same. Consequently, if the switching frequency for switching between the energized and de-energized states of the single electromagnet 61 placed between the first and second movable parts is set to the same frequency as or near the common resonant frequency of the first and second movable parts, both the first and second movable parts can be brought into a resonant state together. As a result, the resonant actuator 6 of this embodiment can 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 the cross-sectional shape of the pump 1 according to this embodiment along the axis of symmetry CA. Figure 5 omits the illustration of elements of the pump 1 that are outside the resonant actuator 6, including the housing 2.

[0048] As shown in Figure 5, the fourth channel 54 and the fifth channel 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, block-shaped components that are fixedly installed on the inner wall surface of the housing 2. The other channels of the channel 5, other than the fourth channel 54 and the fifth channel 55, are similarly holes provided in the support 9. In the example in Figure 5, the support 9 to which the channel 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 shown as an integrated part, but it is also possible to have a configuration in which separate parts are integrally connected. Similarly, the first to eighth channels 51 to 58 that constitute the channel 5 are each provided on separate supports, and these supports are connected to form the channel 5.

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

[0050] The cylinder 73 of the first pump chamber 7 is formed with openings on the Z-positive and Z-negative sides of the support 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 positioned so that their axial directions coincide with those of the first pump chamber 7, i.e., coincide with the axial direction of the cylinder 73. Therefore, as shown in Figure 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 with openings on the Z-positive and Z-negative sides of the support 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 positioned so that their axial directions coincide with those of the second pump chamber 8, i.e., coincide with the axial direction of the cylinder 83. Therefore, as shown in Figure 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 installed in the first movable plate 62 and the second movable plate 63, respectively. Therefore, in conjunction with the vibrational motion of the first movable plate 62 and the second movable plate 63 in the Z direction, controlled by the energization of the electromagnet 61, the first pistons 71, 81 and the second pistons 72, 82 slide within the respective cylinders 73, 83, repeatedly moving closer to and further apart from each other. This allows the volume of the first pump chamber 7 and the second pump chamber 8 to be increased or decreased.

[0053] Figure 6 is a schematic diagram of the axial cross-sectional shape of the fourth passage 54 of the pump 1 according to this embodiment. As shown in Figure 6, an intake valve 74 and a discharge valve 75 are provided on the upstream and downstream sides of the first pump chamber 7 within the fourth passage 54, respectively. When the first piston 71 and the second piston 72 move closer together in the cylinder 73 and the volume of the first pump chamber 7 decreases, the intake valve 74 is configured to close to stop the inflow of fluid from the upstream side of the fourth passage 54 into the first pump chamber 7, and the discharge valve 75 is configured to open to discharge fluid from the first pump chamber 7 to the downstream side of the fourth passage 54. On the other hand, when the first piston 71 and the second piston 72 move further apart in the cylinder 73 and the volume of the first pump chamber 7 increases, the intake valve 74 is configured to open to allow fluid to flow from the upstream side of the fourth passage 54 into the first pump chamber 7, and the discharge valve 75 is configured to close to stop the discharge of fluid from the first pump chamber 7 to the downstream side of the fourth passage 54.

[0054] Figure 6 illustrates a configuration for achieving this effect in which both the intake valve 74 and the discharge valve 75 have a sphere positioned upstream of the fourth flow path 54 to seal the flow path, and a spring on the downstream side that biases this sphere upstream. However, the intake valve 74 and the discharge valve 75 may have structures other than those shown in Figure 6.

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

[0056] Although Figure 6 illustrates the cross-section of the fourth flow path 54 and explains the configuration of the first pump chamber 7, the configuration of the second pump chamber 8 in the fifth flow path 55 is similar. That is, the area between the lower end surface of the first piston 81 and the upper end surface of the second piston 82 within the cylinder 83 constitutes the volume of the second pump chamber 8. This volume increases or decreases in accordance with the vertical movement of the first piston 81 and the second piston 82 within the cylinder 83.

[0057] [Pump operation] The operation of the pump 1 according to this embodiment will be explained with reference to Figures 7 to 10.

[0058] Figure 7 is a schematic diagram showing the operation of pump 1 when the coil is energized. Figure 8 is a schematic diagram showing the area around the first pump chamber 7 in the state shown in Figure 7. The outlines of Figures 7 and 8 are the same as those of Figures 5 and 6.

[0059] As shown in Figure 7, when the coil 612 of the electromagnet 61 is energized, a magnetic field M1 is generated passing 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, which is installed penetrating the center of the coil 612. In the example in Figure 7, a magnetic field M1 directed towards the positive X direction is generated inside the winding portion 611A.

[0060] The magnetic field M1 generated in this way branches in the positive Z and negative Z directions along the protruding direction of one of the widening sections 611B, which is located on the X-positive side of the winding section 611A of the core 611. Next, it flows through the interior of the first movable plate 62 and the second movable plate 63, which are located opposite each other on the upper and lower end surfaces of the widening section 611B, towards the X-negative side. Then, from the upper and lower end surfaces of the other widening section 611B, which is located on the X-negative side of the winding section 611A, it flows through the interior of this widening section 611B toward the central part in the Z direction, merges, and then flows back into the winding section 611A. In other words, when viewed from the Y-negative side, the magnetic field M1 exemplified in Figure 7 flows clockwise on the first movable plate 62 side and counterclockwise on the second movable plate 63 side.

[0061] As a result of the generation of this magnetic field M1, the first movable plate 62 is attracted to the electromagnet 61 and moves toward the negative Z direction, as shown by arrow A in Figure 7. Similarly, the second movable plate 63 is attracted to the electromagnet 61 and moves toward the positive Z direction, as shown by arrow B.

[0062] As the first movable plate 62 and the second movable plate 63 move toward the side attracted to the electromagnet 61, the first piston 71 slides in the negative Z direction within the cylinder 73, as indicated by arrow C, and 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 move closer to each other, reducing the volume of the first pump chamber 7.

[0063] Similarly, in the second pump chamber 8, the first piston 81 slides within the cylinder 83 in the negative Z direction, as indicated by arrow E. Also, the second piston 82 slides within the cylinder 83 in the positive Z direction, 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 move closer to each other, reducing the volume of the second pump chamber 8.

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

[0065] Furthermore, as the first movable plate 62 moves toward the side 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 fixedly installed on the support 9, the central portion 641 is displaced toward the negative Z direction relative to the fixed end 642. Figure 7 shows the position of the first leaf spring 64 in the Z direction in the steady state as shown in Figure 5, indicated by the dotted line S1. As a result of this displacement, the deflection portion 643 located between the central portion 641 and the fixed end 642 undergoes elastic deformation toward the negative Z direction, and as a result, a biasing force f1 is generated in the deflection portion 643 to elastically return toward the positive Z direction, as shown by the dotted arrow f1 in Figure 7.

[0066] Similarly, as the second movable plate 63 moves toward the side 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, since the fixed end 652 of the second leaf spring 65 is fixedly installed on the support 9, the central portion 651 is displaced toward the positive Z direction relative to the fixed end 652. Figure 7 shows the position of the second leaf spring 65 in the Z direction in the steady state as shown in Figure 5, indicated by the dotted line S2. As a result of this displacement, the deflection portion 653 located between the central portion 651 and the fixed end 652 elastically deforms toward the positive Z direction, and as a result, a biasing force f2 is generated in the deflection portion 653 to elastically return toward the negative Z direction, as shown by the dotted arrow f2 in Figure 7.

[0067] As shown in Figure 7, when the first pistons 71 and 81 and the second pistons 72 and 82 move closer together, 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 spheres of the suction valve 74 and the discharge valve 75 are pressed upstream and downstream of the fourth flow path 54, respectively, by the fluid in the first pump chamber 7. At this time, the sphere 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 sphere of the discharge valve 75 is movable downstream as indicated 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 mentioned above, the reduction in volume between the first pump chamber 7 and the second pump chamber 8 is the same. Therefore, in the second pump chamber 8, the fluid 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] Figure 9 is a schematic diagram showing the operation of pump 1 when the coil is switched from energized to de-energized as shown in Figure 7. Figure 10 is a schematic diagram showing the area around the first pump chamber 7 in the state shown in Figure 9. The outlines of Figures 9 and 10 are the same as those of Figures 5 and 6.

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

[0071] As the magnetic field M1 disappears, the attractive force that the first movable plate 62 and the second movable plate 63 were receiving from the electromagnet 61 also disappears. Therefore, the biasing force f1 generated at the deflected portion 643 of the first leaf spring 64, as shown by the dotted arrow in Figure 7, causes the first leaf spring 64 to return to its elastic state, and in response to this movement, the first movable plate 62 also moves toward the positive Z direction. However, since the attractive force that was balancing the biasing force f1 has disappeared, neither the first movable plate 62 nor the first leaf spring 64 comes to rest at the steady position S1, but moves further toward the positive Z direction. Finally, as shown by the arrow H in Figure 9, they move toward the positive Z direction from the steady position S1 by an amount equal to the amount of movement due to the attraction of the electromagnet 61. Similarly, as indicated by arrow I, the second movable plate 63 and the second leaf spring 65 also move from the steady position S2 toward the negative Z direction due to the biasing force f2 in the negative Z direction that was generated in the deflected portion 653.

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

[0073] Similarly, in the second pump chamber 8, the first piston 81 slides within the cylinder 83 in the positive Z direction, as indicated by arrow L. Also, the second piston 82 slides within 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 are separated from each other, increasing the volume of the second pump chamber 8.

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

[0075] As shown in Figure 9, when the first pistons 71 and 81 and the second pistons 72 and 82 move apart, the volumes of the first pump chamber 7 and the second pump chamber 8 increase. As a result, as shown in Figure 10, in the first pump chamber 7, the spheres of the intake valve 74 and the discharge valve 75 are drawn towards the cylinder 73 by the fluid in the first pump chamber 7. At this time, the sphere of the discharge valve 75 moves to block the upstream side of the fourth passage 54 as indicated by arrow N, so the discharge valve 75 is closed. On the other hand, the sphere of the intake valve 74 can move downstream as indicated by arrow O, so the intake valve 74 is opened. As a result, the fluid on the upstream side of the fourth passage 54 is drawn into the first pump chamber 7.

[0076] As mentioned above, the volume increases of the first pump chamber 7 and the second pump chamber 8 are the same. Therefore, in the second pump chamber 8, the fluid upstream of the fifth flow path 55 is drawn into the second pump chamber 8, similar to the operation of the first pump chamber 7 shown in Figure 10.

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

[0078] In this control system, 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 mounted. 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, in the pump 1 of this embodiment, the discharge of fluid at a desired pressure can be controlled by controlling the current value flowing through the coil 612 of the resonant actuator 6.

[0079] Alternatively, in the pump 1 of this embodiment, the discharge of fluid at a desired pressure can also be controlled by adjusting various structural elements, such as the number of turns of the wire in the coil 612 of the electromagnet 61, the dimensions of the winding portion 611A of the core 611 in the X and Y directions, the amount of protrusion in the Z direction and the dimensions in the X and Y directions of the widening portion 611B of the core 611, the area and shape of the first movable plate 62 and the second movable plate 63 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 the magnetic field M1 generated when the electromagnet 61 is energized, 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 respectively, biasing the first movable plate 62 and the second movable plate 63 in the opposite direction to the attraction movement of the first movable plate 62 and the second movable plate 63 to the electromagnet 61, a fluid passage 5 through which fluid flows, a first pump chamber 7 and a second pump chamber 8 provided on the passage 5, and a first leaf spring 64 and a second leaf spring 65 that operate to reduce the volume of the first pump chamber 7 and the second pump chamber 8 in response to the attraction movement of the first movable plate 62 and the second movable plate 63, and when the electromagnet 61 is de-energized after the attraction movement, the electromagnet 64 The system includes, as an example of a volume-changing member that operates to increase the volume of the first pump chamber 7 and the second pump chamber 8 in response to a separation operation that moves away from 1, a first piston 71, 81 and a second piston 72, 82, which open when the first piston 71, 81 and the second piston 72, 82 move in the direction of increasing the volume of the first pump chamber 7 and the second pump chamber 8, drawing fluid into the first pump chamber 7 and the second pump chamber 8 from the upstream side of the flow path 5, and a discharge valve 75, which is provided on the downstream side of the flow path 5 in the first pump chamber 7 and the second pump chamber 8, which opens when the first piston 71, 81 and the second piston 72, 82 move in the direction of decreasing the volume of the first pump chamber 7 and the second pump chamber 8, which discharges fluid from the first pump chamber 7 and the second pump chamber 8 to the downstream side of the flow path 5.

[0081] Here, the electromagnet 61 among the above components can also be described as the "fixed part." Furthermore, the first movable plate 62 and the second movable plate 63, and the first leaf spring 64 and the second leaf spring 65 can also be described as "movable parts that are attracted to the fixed part by the magnetic field generated when the electromagnet 61 is energized, and that perform a vibration operation that separates them from the fixed part by the biasing force generated when the electromagnet 61 is not energized."

[0082] With this configuration, the vibration generated in the movable parts (first movable plate 62 and second movable plate 63, first leaf spring 64 and second leaf spring 65) by the fixed part (electromagnet 61) allows 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 the drive source for the pump 1. As a result, the amount of piston movement required to increase or decrease the volume of the first pump chamber 7 and the second pump chamber 8 can be reduced compared to a conventional solenoid-driven metering pump, thereby reducing vibration during pump 1 operation. 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 the vibration element, the movable part can be made to resonate. 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. As a result, the pump 1 of this embodiment can be made highly efficient.

[0083] Furthermore, in the pump 1 of this embodiment, the first movable plate 62 and the second movable plate 63 are arranged opposite each other with an electromagnet 61 in between. 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. In other words, the first leaf spring 64 and the second leaf spring 65 are also arranged opposite each other with an electromagnet 61 in between. The first pistons 71 and 81 are installed on the first movable plate 62 and move in conjunction with the operation of the first movable plate 62. The second pistons 72 and 82 are installed on the second movable plate 63 and move in conjunction with the operation of the second movable plate 63.

[0084] This configuration allows a single electromagnet 61 to synchronize the vibration of a pair of opposing movable parts (the first movable plate 62 and the first leaf spring 64, and the second movable plate 63 and the second leaf spring 65). Since the pair of movable parts are positioned opposite each other with the electromagnet 61 in between, they are attracted to the electromagnet 61 in opposite directions. Therefore, the vibration directions of the pair of movable parts are in opposite phase. This allows the vibrations generated in the pump 1 by the operation of each movable part to cancel each other out.

[0085] Furthermore, 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 a fixed part (electromagnet 61) in between. The first pistons 71 and 81 are linked to the operation of the first movable part, and the second pistons 72 and 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] This configuration allows for the sharing of a common pump chamber where a pair of pistons are installed, meaning that only one flow path (fourth flow path 54) and one valve (suction valve 74, discharge valve 75) are needed for the 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 needed for the 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 of the operation of the pair of opposing movable parts is reduced. As a result, the number of parts is reduced while increasing the number of pump chambers and improving pump efficiency.

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

[0088] In the comparative example shown in Figure 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 Figure 7, etc. The core 611C is formed so that the dimensions in the Z direction are uniform throughout the entire X direction. In other words, the core 611C has a shape in which the winding 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] In the case of the core 611C shape shown in Figure 11, when the coil 612 is energized, a magnetic field M2 is generated inside the core 611C in the positive X direction. This magnetic field M2 initially enters the space of the resonant actuator 6 in the positive X direction from the X-positive end of the core 611C. After that, it branches into the positive Z direction and the negative Z direction, curves, reverses direction, and enters the interior from the X-positive ends of the first movable plate 62 and the second movable plate 63, heading towards the negative X direction. Then, from the X-negative ends of the first movable plate 62 and the second movable plate 63, it again enters the space of the resonant actuator 6 in the negative X direction, curves into the negative Z direction and the positive Z direction, reverses direction to the positive X direction, merges, and flows into the X-negative end of the core 611C.

[0090] In other words, the magnetic field M2 of the comparative example illustrated in Figure 11 is similar to the magnetic field M1 of the embodiment shown in Figure 7 in that, when viewed from the negative Y direction side, the flow is 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 tends to increase in magnetic resistance because a larger proportion of it flows within the space of the resonant actuator 6 compared to the magnetic field M1 of the embodiment, meaning the air gap is larger.

[0091] In contrast, in the electromagnet 61 of this embodiment, by providing a widened portion 611B on the core 611, as shown in Figure 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 decreases magnetic resistance, so that magnetic force can be generated more efficiently than in the comparative example.

[0092] Furthermore, in this embodiment, the core 611 of the electromagnet 61 is formed by stacking multiple electromagnetic steel sheets in the Y direction, as shown in Figures 3 and 4. Since adjacent electromagnetic steel sheets are bonded together with adhesive, this adhesive portion becomes an air gap, which acts as magnetic resistance, making it difficult for magnetic flux to flow. The magnetic flux generated by the coil 612 flows through the core 611 toward the movable plates 62 and 63. Therefore, if the stacking direction is the Y direction as in this embodiment, the air gap is positioned parallel to the flow of magnetic flux, resulting in reduced obstruction to the flow of magnetic flux and improved energy transfer efficiency.

[0093] On the other hand, in a configuration where the stacking direction is 90 degrees different from that of this embodiment, that is, the X direction is the stacking direction, the air gap is placed in a position that obstructs the flow of magnetic flux, resulting in reduced efficiency.

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

[0095] When the direction perpendicular to the direction (X direction) of the magnetic field M1 generated by the electromagnet 61 (Y direction) is defined as the width direction, as shown in Figure 12, the widthwise dimension W1 of at least the flex portion 643 of the first leaf spring 64 is formed to be larger than the widthwise dimension W2 of the first movable plate 62. Similarly, in Figure 12, the relationship between the second movable plate 63 and the second leaf spring 65, which are hidden in the background of the figure, is also such that the widthwise dimension W1 of at least the flex portion 653 of the second leaf spring 65 is formed to be larger than the widthwise dimension W2 of the second movable plate 63.

[0096] As explained with reference to Figure 7, when the electromagnet 61 is energized during the operation of the resonant actuator 6, the first movable plate 62 and the second movable plate 63 ideally move in parallel in the direction approaching the electromagnet 61 (Z direction) due to the magnetic field M1 generated by the electromagnet 61. However, if a magnetic field M1 with uneven magnetic flux density is generated across the width direction of the movable plates 62 and 63, twisting may occur during operation, such as tilting of the first movable plate 62 or the second movable plate 63 in the X or Y direction. Therefore, as in this embodiment, by making the width dimension W1 of the leaf springs 64 and 65 larger than that of the movable plates 62 and 63, the twisting of the movable plates 62 and 63 during operation can be more easily absorbed by the leaf springs 64 and 65, making it possible to move the first movable plate 62 and the second movable plate 63 in parallel more stably. As a result, the pump 1 of this embodiment can reduce noise and vibration in a configuration in which the resonant actuator 6 is used as the drive source.

[0097] Furthermore, the first pump chamber 7 and the second pump chamber 8 are positioned opposite each other at the locations where a pair of first pistons 71 and 81 are provided at both ends of the first movable plate 62 along the direction of the magnetic field M1 (X direction). Similarly, the second movable plate 63 is positioned opposite each other at the locations where a pair of second pistons 72 and 82 are provided at both ends along the direction of the magnetic field M1 (X direction). In this configuration with two pump chambers, since two pistons are installed on a single movable plate, the relationship between the widthwise dimension W1 of the leaf springs 64 and 65 and the widthwise dimension W2 of the movable plates 62 and 63 allows for stabilization of the sliding of the two pistons on a single movable plate relative to each pump chamber 7 and 8, thus particularly demonstrating the effect of suppressing twisting of the movable plates 62 and 63.

[0098] Next, the effects of the arrangement of the first pump chamber 7 and the second pump chamber 8 will be explained. As shown in Figures 2 and 7, the fourth flow path 54 of the flow path 5 of the pump 1, which includes the first pump chamber 7, is positioned adjacent to the winding portion 611A of the core 611 of the electromagnet 61, on the opposite side (negative X direction side), with the widened portion 611B on the negative X direction side of the core 611, and the flow direction is aligned with the width direction (Y direction). Similarly, the fifth flow path 55 of the flow path 5 of the pump 1, which includes the second pump chamber 8, is positioned adjacent to the winding portion 611A of the core 611 of the electromagnet 61, on the opposite side (positive X direction side), with the widened portion 611B on the positive X direction side of the core 611, and the flow direction is aligned with the width direction (Y direction).

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

[0100] By providing 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 the magnetic flux concentrates and passes through the upper and lower end surfaces of the widened portions 611B, as shown in Figure 7. In other words, when the electromagnet 61 is energized, the portion of the first movable plate 62 facing the upper end surface of the widened portion 611B receives the strongest attractive force, and the portion of the second movable plate 63 facing the lower end surface of the widened portion 611B receives the strongest attractive force. Therefore, by arranging the first pistons 71, 81 and the second pistons 72, 82 adjacent to the widened portion 611B, each piston can be positioned near the portion of the first movable plate 62 and the second movable plate 63 that receives the strongest attractive force from the electromagnet 61. This makes it possible to efficiently apply sliding external force from the first movable plate 62 and the second movable plate 63 to the first pistons 71 and 81 and the second pistons 72 and 82, thereby improving the operating efficiency of both the first pump chamber 7 and the second pump chamber 8.

[0101] Furthermore, by positioning the first pistons 71, 81 and the second pistons 72, 82 near the point where the first movable plate 62 and the second movable plate 63 receive the strongest attractive force from the electromagnet 61, the attractive force generated when the electromagnet 61 is energized can further suppress the twisting of the direction of movement of the first pistons 71, 81 and the second pistons 72, 82 during the suction operation. As a result, the direction of movement of the first pistons 71, 81 and the second pistons 72, 82 can be aligned with the axial direction (Z direction) of the cylinders 73, 83 of each pump chamber 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 higher efficiency in a configuration that uses the resonant actuator 6 as a drive source.

[0102] Furthermore, the first pump chamber 7 is positioned adjacent to the core 611 of the electromagnet 61 on the opposite side (negative X direction) from the winding portion 611A, with one of the pair of widened portions 611B of the core 611 in between. The second pump chamber 8 is positioned adjacent to the winding portion 611A on the opposite side (positive X direction) from the pair of widened portions 611B, with the other of the pair of widened portions 611B in between. In this configuration with two pump chambers, since two pistons are installed on a single movable plate, by positioning each pump chamber 7 and 8 adjacent to the widened portion 611B, it becomes easier to equalize the external force applied to the two pistons provided on the single movable plate, and it becomes easier to synchronize the sliding of the pistons in each pump chamber 7 and 8. This particularly enhances the operational efficiency of the pump chambers.

[0103] Furthermore, as shown in Figure 2 and other figures, it is preferable that both the first pump chamber 7 and the second pump chamber 8 are positioned on the axis of symmetry CA of the housing 2. As shown in Figure 7 and other figures, the coil 612 of the electromagnet 61 is positioned so that its central axis is the axis of symmetry CA, so the magnetic flux tends to be most concentrated on the axis of symmetry CA on the center side of the coil 612. Therefore, the first movable plate 62 and the second movable plate 63 are most likely to receive the strongest attractive force from the electromagnet 61 on the axis of symmetry CA. For this reason, if the first pump chamber 7 and the second pump chamber 8 are positioned on the axis of symmetry CA, the first pistons 71, 81 and the second pistons 72, 82 are also positioned on the axis of symmetry CA, so it becomes possible to efficiently apply sliding external force from the first movable plate 62 and the second movable plate 63 to the first pistons 71, 81 and the second pistons 72, 82, further improving the operating efficiency of the first pump chamber 7 and the second pump chamber 8.

[0104] [Examples of applications for Pump 1] Figure 13 shows an example of the application of the pump 1 according to this embodiment. As shown in Figure 13, the pump 1 according to this embodiment can be applied to a beverage supply device such as an espresso machine 100.

[0105] The espresso machine 100 comprises a tank 101, a heater 102, a damper 103, and an extraction unit 104.

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

[0107] Pump 1 pressurizes the water transported from tank 101 and sends it to heater 102. In the case of an espresso machine 100, it is preferable for pump 1 to pressurize 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] The extraction unit 104 has powdered coffee beans 105 packed into the bottom and is pressed downwards by a damper 103. Hot water heated and pressurized by a heater 102 is supplied to the pressed coffee bean powder 105, and coffee is extracted from the extraction hole 106 at the bottom end of the extraction unit 104.

[0110] Espresso machines require a high-pressure pump to extract coffee under high pressure. Therefore, conventional espresso machines often utilize solenoid-driven metering pumps. However, solenoid-driven metering pumps have drawbacks such as high vibration and poor efficiency.

[0111] In contrast, the pump 1 of this embodiment uses a resonant actuator 6 as a drive source, thus solving the problems of the conventional solenoid-driven metering pump described above and providing a more convenient espresso machine 100.

[0112] Furthermore, pump 1 can be applied to any beverage supply device that requires pressure boosting, not just the espresso machine 100. Such a beverage supply device only needs to include at least a tank for storing beverages, a pump 1 according to the embodiment that sucks the beverage from the tank and discharges it at a predetermined pressure, and a discharge unit (corresponding to the extraction unit 104 in the example of Figure 13) that discharges the beverage discharged from pump 1.

[0113] Furthermore, pump 1 can be applied to any device other than beverage supply equipment that requires pressure boosting. Examples of such devices include industrial manufacturing equipment (such as semiconductor manufacturing equipment), medical equipment, household equipment (such as toilets, washbasins, and bathtubs), and agricultural equipment.

[0114] <First variation> Figure 14 shows the configuration of the flow path 5A of pump 1A according to the first modified example. The overview of Figure 14 corresponds to Figure 2, but the second flow path 52 and subsequent flow paths of the flow path 5A are shown with dotted lines, and the internal structure of the housing 2 on the Y-positive side from the electromagnet 61 is omitted from the illustration. In addition, the electromagnet 61, which was only shown as a rectangle in Figure 2, is shown with its core 611 and coil 612.

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

[0116] The cooling channel 59 is provided by branching off from the channel 5A. In the example shown in Figure 14, the cooling channel 59 is provided by branching off from the second channel 52 and the third channel 53 at the downstream end of the first channel 51 of the channel 5A. The cooling channel 59 extends toward the positive Y direction and is provided to reach a position adjacent to the negative Y direction side of the coil 612 of the electromagnet 61. The tip of the cooling channel 59 on the positive Y direction side is sealed. Preferably, the tip of the cooling channel 59 on the Y direction side is positioned approximately in the center of the coil 612 in the X direction.

[0117] Figure 15 is a side view showing an example configuration of the cooling channel 59 and heat absorption sections 11 and 12 shown in Figure 14. Figure 15 is a cross-sectional view along the axial direction of the cooling channel 59, and in addition to the cooling channel 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 Figure 15, the tip of the cooling channel 59 on the positive Y-direction side is provided with a first hole 59A that opens in the positive Z-direction and a second hole 59B that opens in the negative Z-direction.

[0119] The pair of heat-absorbing sections 11 and 12 are plate materials made of a conductor such as metal, and are formed to be in surface contact with the outer surface of the cooling channel 59 and the outer surface of the coil 612. One heat-absorbing section 11 is positioned to be in surface contact with the cooling channel 59 and the coil 612 from the positive Z direction side. The heat-absorbing section 11 is also positioned to block the first hole 59A of the cooling channel 59. The other heat-absorbing section 12 is positioned to be in surface contact with the cooling channel 59 and the coil 612 from the negative Z direction side. The heat-absorbing section 12 is also positioned to block the second hole 59B of the cooling channel 59.

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

[0121] The heat-absorbing sections 11 and 12 are cooled by contact with the fluid through the first hole 59A and the second hole 59B. In addition, the heat-absorbing sections 11 and 12 absorb heat generated by the energization of the coil 612 from the contact portion with the coil 612, thereby absorbing heat from the coil 612.

[0122] Thus, in the pump 1A according to the first modified example, heat can be absorbed from the coil 612 of the electromagnet 61 using the cooling channel 59 and the heat absorption sections 11 and 12, thereby suppressing the temperature rise of the coil 612. This suppresses the decrease in pump performance caused by the temperature rise of the coil 612, and thus suppresses the performance degradation of the pump 1A due to heat generation from the drive source.

[0123] Furthermore, it is preferable that the cooling channel 59 be branched off from the channel 5A 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 its pre-pressurized state in the pump chambers, and therefore is not affected by temperature changes due to pressurization, resulting in a stable cooling effect.

[0124] In the example shown in Figure 14, the cooling channel 59 is shown as branching off from the channel 5A, but the channel 5A may be used as the cooling channel 59. In this case, the first hole 59A and the second hole 59B are provided at arbitrary positions in the channel 5A, and the heat-absorbing sections 11 and 12 are installed at the positions where the first hole 59A and the second hole 59B are provided on the channel 5A. In any case, the cooling channel 59 can be included in the expression "part of the channel 5A".

[0125] <Second variation> Figure 16 shows the configuration of the flow path 5B of pump 1B according to the second modified example. The outline of Figure 16 corresponds to Figure 2.

[0126] As shown in Figure 16, the arrangement of the intake port 3 and the outlet port 4 may be changed. In the example in Figure 16, the intake port 3 is installed on the negative X-direction side of the side 25 of the housing 2, and the outlet port 4 is installed on the positive X-direction side of the side 26. Both the intake port 3 and the outlet port 4 are in communication in the Y direction. The upstream end of the first flow path 51 of the flow path 5B is connected to the intake port 3 at approximately perpendicular. Similarly, the downstream end of the eighth flow path 58 of the flow path 5B is connected to the outlet port 4 at approximately perpendicular.

[0127] In addition to the example in Figure 16, the intake port 3 and outlet port 4 may be placed at any position on the housing 2, for example, by providing them on a pair of main surfaces 21 and 22.

[0128] <Third variation> Figure 17 shows the configuration of the flow path 5C of pump 1C according to the third modified example. The outline of Figure 17 corresponds to Figure 2.

[0129] As shown in Figure 17, in the flow path 5C, the arrangement of the first pump chamber 7 and the second pump chamber 8 does not have to be in positions other than the axis of symmetry CA, but at least the fourth flow path 54 and the fifth flow path 55. For example, as shown in Figure 17, the first pump chamber 7 may be located upstream of the flow path 5C on the negative Y side of the axis of symmetry CA. Alternatively, as shown in Figure 17, the second pump chamber 8 may be located downstream of the flow path 5C on the positive Y side of the axis of symmetry CA.

[0130] Furthermore, if the positions of the first pump chamber 7 and the second pump chamber 8 in the Y direction are the same, the attractive force received by the first movable plate 62 and the second movable plate 63 from the electromagnet 61 can be made equal, thereby equalizing the pump performance of the first pump chamber 7 and the second pump chamber 8.

[0131] <Fourth variation> Figure 18 is a schematic diagram of the cross-sectional shape of pump 1D along the axis of symmetry CA according to the fourth modified example. The outline of Figure 18 corresponds to Figure 5.

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

[0133] In the example shown in Figure 18, the cylinder 73A of the first pump chamber 7 is formed to allow the first piston 71 to pass through, with an opening only on the side of the first movable plate 62, and is sealed without an opening on the side of the second movable plate 63. The cylinder 83A of the second pump chamber 8 is formed to allow the second piston 82 to pass through, with an opening only on the side of the second movable plate 63, and is sealed without an opening on the side of the first movable plate 62.

[0134] Even with this configuration where only a single piston is installed in one pump chamber, for example, as shown by the arrow in Figure 18, 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, the same pump performance as the pump 1 of the embodiment can be achieved.

[0135] <Fifth variation> Figure 19 shows the configuration of the flow path 5E of pump 1E according to the fifth modified example. The outline of Figure 19 corresponds to Figure 2.

[0136] As shown in Figure 19, the flow path 5E may be configured to have only a single pump chamber 7A. In this case, it is preferable that the pump chamber 7A is positioned on the axis of symmetry CA and the axis of symmetry CB, that is, at the center line CO of the housing 2. This makes it possible to more uniformly distribute 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 stabilizing the pump performance.

[0137] When the pump chamber 7A is arranged in this manner, the flow path 5E may consist only of a first flow path 51 connected to the inlet 3, an eighth flow path 58 connected to the outlet 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 the axial direction. The intermediate flow path 55A may be installed, for example, to penetrate the winding portion 611A or coil 612 of the core 611 of the electromagnet 61 along the Y direction.

[0138] Furthermore, in the configuration of the flow path 5 shown in Figure 2, it is also possible to provide only one of either the first pump chamber 7 or the second pump chamber 8.

[0139] <Sixth variation> Figure 20 shows the configuration of the flow path 5F of pump 1F according to the sixth modified example. The outline of Figure 20 corresponds to Figure 2.

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

[0141] In the example shown in Figure 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 intake port 3 at their upstream ends. The first flow path 91 is arranged to extend in the positive Y direction. The second flow path 92 is arranged to extend in the positive X direction.

[0142] The third channel 93 is connected to the downstream end of the first channel 91 at its upstream end. The third channel 93 extends in the positive X direction. The fourth channel 94 is connected to the downstream end of the third channel at its upstream end. The fourth channel 94 extends in the negative Y direction.

[0143] The second channel 92 and the fourth channel 94 are connected to the discharge port 4 at their downstream ends.

[0144] Furthermore, in the example shown in Figure 20, the first to fourth channels 91 to 94 of the channel 5F are arranged to surround the outer circumference of the electromagnet 61 of the resonant actuator 6 when viewed in the Z direction. The first channel 91 and the fourth channel 94 are arranged to extend along the shorter side of the rectangular outer shape of the electromagnet 61. The second channel 92 and the third channel 93 are arranged to extend along the longer side of the rectangular outer shape of the electromagnet 61.

[0145] Furthermore, in the case of the flow path 5F illustrated in Figure 20, the first pump chamber 95 is positioned at the center of the extending direction (X direction) of the third flow path 93, and the second pump chamber 96 is positioned at the center of the extending direction (X direction) of the second flow path 92. That is, it is preferable that both the first pump chamber 95 and the second pump chamber 96 are positioned on the axis of symmetry CB extending in the Y direction. In the example of Figure 20, since the first pump chamber 95 and the second pump chamber 96 are positioned in this way, the first movable plate 62 and the second movable plate 63 of the resonant actuator 6 are formed such that the end faces on the Y-positive direction side in the width direction (Y direction) extend to a position on the Y-positive side beyond the first pump chamber 95 and the third flow path 93, and the end faces on the Y-negative direction side extend to a position on the Y-negative side beyond the second pump chamber 96 and the second flow path 92.

[0146] Figure 21 shows an example of a configuration in which the same coil cooling structure as in the first modified example is applied to pump 1F according to the sixth modified example. The outline of Figure 21 corresponds to Figure 14.

[0147] In the sixth modified example, pump 1F has a cooling channel 97 and a heat absorption section 13 as the coil cooling structure.

[0148] The cooling channel 97 is provided by branching off from the channel 5F. In the example shown in Figure 21, the cooling channel 97 is provided by branching off to the positive X direction at the center of the extending direction (Y direction) of the first channel 91 (on the axis of symmetry CA). The cooling channel 97 extends from the first channel 91 toward the positive X direction and is provided to reach a position adjacent to the negative X direction side of the widened portion 611B on the negative X direction side of the core 611 of the electromagnet 61. The tip of the cooling channel 97 toward the positive X direction is sealed.

[0149] A hole 97A is provided at the tip of the cooling channel 97 on the X-positive side, opening in the Z-positive direction. The heat-absorbing portion 13 is a plate made of a conductive material such as metal, and is formed to be in surface contact with the outer surface of the cooling channel 97 and the outer surface of the widened portion 611B on the X-negative side. The heat-absorbing portion 13 is positioned to be in surface contact with the cooling channel 97 and the widened portion 611B from the Z-positive side. The heat-absorbing portion 13 is also installed to block the hole 97A of the cooling channel 97.

[0150] The fluid flowing in the X-positive direction through the cooling channel 97 enters the hole 97A at its tip and comes into contact with the portion of the heat-absorbing section 13 that is exposed to the hole 97A. The heat-absorbing section 13 is cooled by contact with the fluid through the hole 97A. In addition, the heat-absorbing section 13 absorbs heat generated by the energization of the coil 612 and transferred to the core 611 from the portion in contact with the widened section 611B, thereby indirectly absorbing heat from the coil 612.

[0151] In addition, the coil cooling structure in the sixth modified example may also be configured in the same way as the first modified example illustrated in Figure 15, with a pair of heat-absorbing parts 13 provided on both sides of the cooling channel 97 in the Z direction. In this case, one of the pair of heat-absorbing parts 13 is arranged to make surface contact with the cooling channel 97 and the widened portion 611B from the positive Z direction side, and the other is arranged to make surface contact with the cooling channel 97 and the widened portion 611B from the negative Z direction side.

[0152] Thus, in the configuration in which the coil cooling structure is applied to the pump 1F according to the sixth modified example, heat can be absorbed from the widened portion 611B of the core 611 of the electromagnet 61 using the cooling channel 97 and the heat absorption portion 13, thereby suppressing the temperature rise of the coil 612 via the widened portion 611B. As a result, the decrease in pump performance caused by the temperature rise of the coil 612 can be suppressed, and thus the decrease in performance due to heat generation from the drive source of the pump 1F can be suppressed.

[0153] Furthermore, it is preferable that the cooling channel 97 is branched off from the channel 5F 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 its pre-pressurized state in the pump chambers, and therefore is not affected by temperature changes due to pressurization, resulting in a stable cooling effect.

[0154] In the example shown in Figure 21, the cooling channel 97 is shown as branching off from the channel 5F, but the channel 5F may be used as the cooling channel 97. In this case, a hole 97A is provided at an arbitrary position in the channel 5F, and the heat absorption section 13 is installed at the position where the hole 97A is provided on the channel 5F. In any case, the cooling channel 97 can be encompassed by the expression "part of the channel 5F".

[0155] <7th variation> Figure 22 is a schematic diagram of the cross-sectional shape of pump 1G along the axis of symmetry CA according to the seventh modified example. The outline of Figure 22 corresponds to Figure 5.

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

[0157] In the example shown in Figure 22, the cylinder 73B of the first pump chamber 7 is formed to allow the first piston 71 to pass through, with an opening only on the side of the first movable plate 62 (positive Z direction), and is sealed without opening on the negative Z direction side. Similarly, the cylinder 83A of the second pump chamber 8 is formed to allow the first piston 81 to pass through, with an opening only on the side of the first movable plate 62 (positive Z direction), and is sealed without opening on the negative Z direction side.

[0158] Even with a configuration in which only a single piston is installed in one pump chamber, for example, as shown by the arrow in Figure 22, 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, the same pump performance as the pump 1 of the embodiment can be achieved.

[0159] [Pump control system] Next, the control systems of the pumps according to the above-described embodiments and their respective modifications will be explained.

[0160] As shown in Figures 2, 14, 16, 17, 19, 20, and 21, the pump 1 according to this embodiment, and the pumps 1A to 1G according to the first to seventh modified examples, are equipped with an intake pressure gauge 14 and an exhaust pressure gauge 15 on the intake side and exhaust side of the flow paths 5, 5A, 5B, 5C, 5E, and 5F inside the pump, respectively. Here, the "intake side of the flow path" refers to the part of the flow paths 5, 5A, 5B, 5C, 5E, and 5F upstream of the pump chambers 7 and 8, i.e., the intake port 3 side. On the other hand, the "exhaust side of the flow path" refers to the part of the flow paths 5, 5A, 5B, 5C, 5E, and 5F downstream of the pump chambers 7 and 8, i.e., the discharge port 4 side.

[0161] The suction-side pressure gauge 14 detects the pressure of the fluid flowing on the suction side of the flow paths 5, 5A, 5B, 5C, 5E, and 5F inside the pump (suction-side pressure P1, see Figure 23). As shown in examples such as Figure 2, it is preferable that the suction-side pressure gauge 14 be positioned adjacent to the downstream side of the suction port 3. This allows the suction-side pressure gauge 14 to measure the pressure of the fluid immediately after it is drawn into the housing 2 from the suction port 3 as the suction-side pressure P1. This minimizes the influence of pressure fluctuations in the pump chambers 7 and 8 within the flow path 5 on the measurement value of the suction-side pressure gauge 14, and allows the suction-side pressure gauge 14 to detect the suction-side pressure P1 with greater accuracy.

[0162] The discharge pressure gauge 15 detects the pressure of the fluid flowing on the discharge side of the flow paths 5, 5A, 5B, 5C, 5E, and 5F inside the pump (discharge pressure P2, see Figure 23). As shown in examples such as Figure 2, it is preferable that the discharge pressure gauge 15 be positioned adjacent to the upstream side of the discharge port 4. This allows the discharge pressure gauge 15 to measure the pressure of the fluid just before it is discharged from the discharge port 4 to the outside of the housing 2 as the discharge pressure P2, thereby minimizing the influence of pressure fluctuations in the pump chambers 7 and 8 within the flow path 5 on the measurement value of the discharge pressure gauge 15, and enabling the discharge pressure gauge 15 to detect the discharge pressure P2 with greater accuracy.

[0163] Note that the intake pressure gauge 14 and the discharge pressure gauge 15 are examples of pressure detection units that detect the pressure of a fluid, and may be replaced with other elements that can detect the pressure of a fluid.

[0164] Figure 23 is a block diagram showing an example of the control system of a pump according to the embodiment and each of its modified examples. As shown in Figure 23, the pump 1 according to the embodiment (and pumps 1A to 1G according to the first to seventh modified examples) includes a control unit 16.

[0165] The control unit 16 controls the operation of the resonant actuator 6 to control the pressure of the fluid discharged from the pump chambers 7 and 8, i.e., the discharge pressure P2. The control unit 16 receives information regarding, for example, the suction pressure P1 detected by the suction pressure gauge 14 and the discharge pressure P2 detected by the discharge pressure gauge 15. Based on the input suction pressure P1 and discharge pressure P2, the control unit 16 derives a control command for the resonant actuator 6, for example, a command value Ic for the current that energizes the conductors constituting the coil 612 of the electromagnet 61, and outputs it to the resonant actuator 6.

[0166] Here, an example of control of the resonant actuator 6 by the control unit 16 is as follows.

[0167] (1) By feeding back the detected value from a pressure gauge (e.g., discharge pressure gauge 15), the pressure of the fluid during discharge (e.g., discharge pressure P2) can be freely changed.

[0168] (2) Even if the pressure of the original fluid (e.g., suction pressure P1) changes, the output pressure (e.g., discharge pressure P2) is controlled to remain constant. This control allows the output pressure to remain constant, for example, when the pump 1 is installed in areas or buildings of varying altitudes or heights, i.e., even when the suction pressure P1 differs from the desired value due to external conditions.

[0169] (3) When an intake pressure gauge 14 is provided, the output pressure (e.g., discharge pressure P2) is controlled according to the pressure of the original fluid (e.g., intake pressure P1). This control allows for efficient operation of the object (e.g., espresso machine 100 (see Figure 13)) by the fluid after it has been output from the pump 1.

[0170] (4) If the discharge pressure gauge 15 detects a value higher than the set pressure, it is determined that a blockage has occurred in one of the flow paths 5, and the operation of the pump 1 is stopped. Alternatively, the system may be configured to refer to the detected values ​​of both the suction pressure gauge 14 and the discharge pressure gauge 15. This allows for earlier detection of malfunctions.

[0171] (5) If the discharge pressure gauge 15 detects a value lower than the set pressure, it is determined that a leak has occurred in one of the flow paths 5, and the operation of the pump 1 is stopped. Alternatively, the system may be configured to refer to the detected values ​​of both the suction pressure gauge 14 and the discharge pressure gauge 15. This allows for earlier detection of malfunctions.

[0172] Physically, the control unit 16 can be configured as a computer system or control board to which a CPU, RAM, ROM, storage device, interface, etc., are connected via a bus. The various functions of the control unit 16 are realized by loading predetermined computer software onto the hardware such as the CPU and RAM, thereby reading and writing data to the RAM and storage device under the control of the CPU, and operating other components of the pump 1, such as the resonant actuator 6, and external devices via the interface.

[0173] Thus, by providing a control unit 16 that generates a control command Ic to the electromagnet 61 of the resonant actuator 6 according to the detected values ​​P1 and P2 of the suction-side pressure gauge 14 and the discharge-side pressure gauge 15, and controls the pressure of the fluid discharged from the pump chambers 7 and 8 (discharge-side pressure P2), the flow rate characteristics of the fluid discharged from the pump 1 can be stabilized.

[0174] Alternatively, the system may be configured to include only one of the suction-side pressure gauge 14 or the discharge-side pressure gauge 15. In this case, if the purpose is to control the stabilization of the pressure of the fluid discharged from the pump 1, it is preferable to have a configuration that includes a discharge-side pressure gauge 15 so that the discharge-side pressure P2 can be observed.

[0175] [Variations of pumps] Figure 24 shows the basic configuration of a diaphragm-type rotary pump 17 as an example of a modified pump. In the above embodiment, a configuration in which a resonant actuator 6 is applied as the drive source for the pump 1 was illustrated, but a configuration using a drive source other than the resonant actuator 6 is also possible, such as the diaphragm-type rotary pump 17 shown in Figure 24.

[0176] The diaphragm rotary pump 17 (hereinafter also referred to as "diaphragm pump 17") is commonly used as a vacuum pump, etc. The diaphragm rotary pump 17 changes the volume of the pump chamber 173 by displacing the diaphragm 172 in accordance with the operation of the drive mechanism 171. In accordance with the change in the volume of the pump chamber 173, it performs the operation of drawing fluid from the inlet 174 to the pump chamber 173 and the operation of discharging fluid from the pump chamber 173 to the outlet 175.

[0177] The oscillating body 176 is configured to oscillate by the driving force of the motor 177 and press against the diaphragm 172. As a result, the diaphragm 172 elastically deforms, expanding and contracting the pump chamber 173. The diaphragm pump 17 also includes a rotating part 178.

[0178] The motor 177, crank stand 179, inclined shaft 180, bearing 181, and oscillating body 176 constitute a drive mechanism 171 that presses against the diaphragm 172 and causes it to elastically deform. The driving force from the motor 177 is transmitted to the diaphragm 172 in the following order: crank stand 179, inclined shaft 180, bearing 181, oscillating body 176, and diaphragm 172.

[0179] The diaphragm pump 17 is configured such that the drive mechanism 171 causes the oscillating body 176 to oscillate around its pivot point 176a. The pivot point 176a is supported by the rotating part 178. As a result, the diaphragm 172 is repeatedly pressed vertically by the oscillating body 176 and repeatedly undergoes elastic deformation. Consequently, the diaphragm 172 repeatedly moves between a pushed-in position (forward position) where it is pushed towards the pump chamber 173 and a non-pushed-down position (retracted position) where it is pushed down to the opposite side of the pump chamber 173.

[0180] In the example shown in Figure 24, when the connection between the inclined shaft 180 and the crank base 179 is to the right of the output shaft of the motor 177, the central axis of the crank base 179, and the position of the pivot point 176a, the oscillating body 176 moves upward from the pivot point 176a, as indicated by arrow Q in the figure. As a result, the diaphragm 172 also moves in the direction of arrow Q, i.e., upward, thereby reducing the volume of the pump chamber 173. The position of the diaphragm 172 shown in Figure 24 is the pushed-in position (forward position) described above.

[0181] On the other hand, when the connection between the inclined shaft 180 and the crank base 179 is to the left in the figure from the output shaft of the motor 177, the central axis of the crank base 179, or the position of the pivot point 176a, the oscillating body 176 moves downward from the pivot point 176a to the right in the figure, as indicated by the arrow R in the figure. As a result, the diaphragm 172 also moves downward in the direction of arrow R, i.e., from the position in Figure 24, thereby increasing the volume of the pump chamber 173. The position of the diaphragm 172 at this time is the non-retracted position (retracted position) described above.

[0182] The diaphragm pump 17 expands the pump chamber 173 and draws fluid in from the suction port 174 during the retraction stroke when the diaphragm 172 moves from the pushed position to the unpushed position. An intake valve 182 is positioned in the flow path between the suction port 174 and the pump chamber 173. The intake valve 182 is configured to open when the diaphragm 172 moves in the direction that increases the volume of the pump chamber 173 (direction of arrow R), allowing fluid to be drawn into the pump chamber 173 from the upstream side of the flow path.

[0183] Furthermore, the diaphragm pump 17 reduces the size of the pump chamber 173 and discharges fluid from the outlet 175 during the pushing stroke (forward stroke) when the diaphragm 172 moves from the non-pushed position to the pushed position. A discharge valve 183 is positioned in the flow path between the outlet 175 and the pump chamber 173. The discharge valve 183 is configured to open when the diaphragm 172 moves in the direction that reduces the volume of the pump chamber 173 (direction of arrow Q), allowing fluid to be discharged from the pump chamber 173 to the downstream side of the flow path.

[0184] The embodiments have been described above with reference to specific examples. However, this disclosure is not limited to these specific examples. Modifications made to these specific examples by those skilled in the art are also included within the scope of this disclosure, as long as they retain the features of this disclosure. The elements and their arrangement, conditions, shapes, etc., of each of the aforementioned specific examples are not limited to those exemplified and can be modified as appropriate. The elements of each of the aforementioned specific examples can be combined in different ways as appropriate, as long as no technical inconsistencies arise.

[0185] In the above embodiment, a configuration using first pistons 71, 81 and second pistons 72, 82 was illustrated as an example of a volume-changing member that "operates to reduce the volume of the pump chambers 7, 8 in response to the attraction of the movable plates 62, 63 toward the electromagnet 61, and operates to increase the volume of the pump chambers 7, 8 in response to the separation movement of the movable plates 62, 63 toward the electromagnet 61 due to the biasing forces f1, f2 of the leaf springs 64, 65 when the electromagnet 61 is switched off after the attraction movement," but elements other than pistons may also be used. Examples of elements other than pistons for the volume-changing member include diaphragms and bellows. [Explanation of symbols]

[0186] Pumps 1, 1A, 1B, 1C, 1D, 1E, 1F, 1G 5, 5A, 5B, 5C, 5E, 5F channel 6. Resonant Actuator 61 Electromagnet (fixed part) 611 cores 611A Winding section 611B Pair of widening sections 612 coil 62 First movable plate (movable part) 63. Second movable plate (movable part) 64. First leaf spring (movable part) 641 Central part 642 Pair of fixed ends 643 Flexible section 65. Second leaf spring (movable part) 651 Central part 652 Pair of fixed ends 653 Flexible section 7. Pump Room 1 71. First piston (volume changing member) 72. Second piston (volume changing member) 74 Inhalation valve 75 Discharge valve 8. Pump Room No. 2 81. First piston (volume changing member) 82. Second piston (volume changing member) 9 Support 59, 97 Cooling channels 11, 12, 13 Heat absorption section 14. Intake-side pressure gauge (intake-side pressure detection unit, pressure detection unit) 15. Discharge side pressure gauge (discharge side pressure detection unit, pressure detection unit) 16 Control Unit P1 Intake pressure P2 Discharge side pressure IC control command 100 Espresso Machines (Beverage Dispensing Devices) 101 Tank 104 Extraction unit (dispensing section) W1: Width dimension of the leaf spring W2 Width dimension of the movable plate

Claims

1. Power source and A fluid channel and A pump chamber provided on the aforementioned flow path, A volume changing member that operates to reduce or increase the volume of the pump chamber in accordance with the operation of the drive source, A suction valve is provided in the pump chamber on the upstream side of the flow path, which opens when the volume changing member moves in the direction of increasing the volume of the pump chamber, and draws the fluid into the pump chamber from the upstream side of the flow path. A discharge valve is provided in the pump chamber on the downstream side of the flow path, which opens when the volume changing member moves in the direction of reducing the volume of the pump chamber, and discharges the fluid from the pump chamber to the downstream side of the flow path. A pressure detection unit is provided on at least one of the intake side and the discharge side of the aforementioned flow path, A control unit generates a control command to the drive source according to the value detected by the pressure detection unit and controls the pressure of the fluid discharged from the pump chamber. A pump equipped with the following features.

2. The pressure detection unit is An intake-side pressure detection unit for detecting the intake-side pressure of the fluid flowing on the intake side of the aforementioned flow path, A discharge-side pressure detection unit for detecting the discharge-side pressure of the fluid flowing on the discharge side of the aforementioned flow path, It has, The control unit generates the control command to the electromagnet based on the intake pressure and the discharge pressure. The pump according to claim 1.

3. The aforementioned drive source is a resonant actuator, The aforementioned resonant actuator is Electromagnets and, A movable plate is attracted to the electromagnet by the magnetic field generated when the electromagnet is energized, The movable plate is attached to a leaf spring that biases the movable plate in the opposite direction to the attraction movement in response to the attraction movement of the movable plate to the electromagnet, It has, The volume-changing member operates to reduce the volume of the pump chamber in response to the suction operation of the movable plate, and operates to increase the volume of the pump chamber in response to the separation operation of the movable plate away from the electromagnet due to the biasing force of the leaf spring when the electromagnet is de-energized after the suction operation. The pump according to claim 1.

4. The volume changing member is a piston installed on the movable plate, The piston is movable in the direction of the suction operation and the separation operation of the movable plate. The pump according to claim 3.

5. A tank for storing beverages, A pump according to any one of claims 1 to 4, which sucks the beverage in the tank and discharges it at a predetermined pressure, A discharge unit for discharging the beverage discharged from the pump, A beverage dispensing device equipped with the following features.

Images