Resonant actuator and pump

Abstract

A resonant actuator comprises: an electromagnet; a first movable plate and a second movable plate as movable parts installed so as to be capable of moving in a prescribed direction toward or away from the electromagnet according to a magnetic field generated by the electromagnet; a securing part for securing the electromagnet; first magnets provided at both ends of the movable parts in a direction orthogonal to the prescribed direction; and second magnets provided at positions of the securing part that face the first magnets. The second magnets are positioned in a manner such that when the movable parts are farthest from the electromagnet, a magnetic force is generated in a direction toward the electromagnet between the first magnets and the second magnets.

Description

Resonant actuator and pump

[0001] The present disclosure relates to a resonant actuator and a pump.

[0002] Pumps that use an electromagnetic actuator as a drive source are known. An electromagnetic actuator is an actuator that vibrates using the magnetic force generated by an electromagnet as energy (for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2005-180332

[0004] In conventional electromagnetic actuators, the vibration direction of the vibrating movable part is the direction approaching and separating from the electromagnet, so that when the movable part moves away from the electromagnet, the electromagnetic attraction force decreases sharply.

[0005] An object of the present disclosure is to provide a resonant actuator and a pump that can stabilize the attraction force toward the electromagnet applied to the movable part regardless of the position of the movable part relative to the electromagnet.

[0006] A resonant actuator according to an aspect of an embodiment of the present invention includes: an electromagnet; a movable part that is movably installed in a predetermined direction approaching and separating from the electromagnet in accordance with the magnetic force generated by the electromagnet; a fixed part that fixes the electromagnet; a pair of first magnets provided at both ends of the movable part in a direction orthogonal to the predetermined direction; and a pair of second magnets provided at positions facing the first magnets in the fixed part.

[0007] According to the present disclosure, it is possible to provide a resonant actuator and a pump that can stabilize the attraction force toward the electromagnet applied to the movable part regardless of the position of the movable part relative to the electromagnet.

[0008] A plan view showing the schematic configuration of the pump according to the embodiment. A diagram showing the first stage of operation of the pump and resonant actuator according to the embodiment. A diagram showing the second stage of operation of the pump and resonant actuator according to the embodiment. A diagram showing the third stage of operation of the pump and resonant actuator according to the embodiment. A diagram showing the first stage of operation of the pump and resonant actuator according to the first modified example. A diagram showing the second stage of operation of the pump and resonant actuator according to the first modified example. A diagram showing the third stage of operation of the pump and resonant actuator according to the second modified example. A plan view showing the schematic configuration of the resonant actuator according to the second modified example.

[0009] The embodiments will be described below with reference to the attached drawings. To facilitate understanding of the explanation, the same reference numerals are used for identical components in each drawing whenever possible, and redundant explanations 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 short-side direction of the housing 2 and the resonant actuator 6, and is the direction of arrangement of the first movable plate 62, electromagnet 61, and second movable plate 63 of the resonant actuator 6. The Y direction is the long-side direction of the housing 2 and the resonant actuator 6, and is the direction of extension of the core 611 of the electromagnet 61. 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] Figure 1 is a plan view showing the schematic configuration of a pump 1 according to an embodiment. Figure 1 is a plan view of the pump 1 as seen from above, and also shows the inside of the housing 2. As shown in Figure 1, the pump 1 comprises a housing 2, an inlet 3, an outlet 4, a flow path 5, and a resonant actuator 6.

[0012] The housing 2 incorporates elements related to the pump function, such as the flow path 5 and the resonant actuator 6. In the example shown in Figure 1, the outer shape of the housing 2 is shown by a dotted line, and the housing 2 is formed in a roughly rectangular shape with the shorter side in the X direction and the longer side in the Y direction when viewed from above.

[0013] The intake port 3 draws fluid W into the housing 2. The outlet port 4 discharges the fluid W, which has been pressurized by the pump function inside the housing 2, to the outside of the housing 2. In the example in Figure 1, both the intake port 3 and the outlet port 4 are located at the center in the X direction on the upper surface of the housing 2 on the Z-positive side. The intake port 3 is located at the Y-positive end of the upper surface of the housing 2, and the outlet port 4 is located at the Y-negative end of the upper surface of the housing 2. The intake port 3 and the outlet port 4 are located on the upper surface of the housing 2. Both the intake port 3 and the outlet port 4 are in communication in the Z direction, and are arranged such that the direction of fluid W intake from the intake port 3 into the housing 2 is the Z-negative direction, and the direction of fluid W discharge from the inside of the housing 2 to the outlet port 4 is the Z-positive direction. Note that the intake port 3 and the outlet port 4 may be located at approximately equidistant distances from the center of the upper surface of the housing 2, as illustrated in Figure 1, or they may not be located at equidistant distances.

[0014] The flow path 5 connects the intake port 3 and the outlet port 4, allowing the fluid W to flow from the intake port 3 to the outlet port 4. In the example shown in Figure 1, the flow path 5 is formed in an annular shape along the outer shape of the housing 2. The flow path 5 includes an intake-side bypass 51, a first pump chamber 7, a second pump chamber 8, and an outlet-side bypass 52.

[0015] The intake bypass 51 is positioned to extend in the X direction from the Y-positive end inside the housing 2. The intake bypass 51 has an upstream end located above the center in the X direction, and this upstream end is connected to the downstream end of the intake port 3. The intake bypass 51 branches from the upstream end in the center in the X direction into the X-positive and X-negative directions, and is positioned so that fluid W flows to the downstream ends of the respective X-positive and X-negative ends.

[0016] The first pump chamber 7 is positioned to extend in the Y direction from the X-positive end inside the housing 2. The upstream end of the first pump chamber 7 on the Y-positive side is connected to the downstream end on the X-positive side of the suction bypass 51, so that the fluid W flows in the Y-negative direction.

[0017] The second pump chamber 8 is positioned to extend in the Y direction from the X-negative end inside the housing 2. The upstream end of the second pump chamber 8 on the Y-positive side is connected to the downstream end on the X-negative side of the suction bypass 51, so that the fluid W flows in the Y-negative direction.

[0018] The discharge bypass 52 is positioned to extend in the X direction from the Y-negative end inside the housing 2. The upstream ends of the discharge bypass 52, both the X-positive end and the X-negative end, are connected to the downstream ends of the first pump chamber 7 and the second pump chamber 8, respectively. The downstream end of the discharge bypass 52 is located above the center in the X direction, and the fluid W flows from the upstream ends at both ends in the X direction to the downstream end in the center of the X direction and merges there. The upstream end of the discharge port 4 is connected to the downstream end of the discharge bypass 52.

[0019] The resonant actuator 6 is positioned in the central space of the annular channel 5. The resonant actuator 6 has an electromagnet 61 and is a device that generates vibrational 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 which are vibrational elements (a group of components including the first movable plate 62, the second movable plate 63, the first coil springs 66A, 66B, the second coil springs 67A, 67B, etc., described later). 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.

[0020] In the example shown in Figure 1, the resonant actuator 6 is positioned such that the Y direction is the longitudinal direction and the X direction is the short direction, and is located in the center of the housing 2 when viewed in the Z direction.

[0021] The resonant actuator 6 includes an electromagnet 61, a first movable plate 62, a second movable plate 63, a pair of first coil springs 66A and 66B, and a pair of second coil springs 67A and 67B.

[0022] The electromagnet 61 is positioned in the center of the resonant actuator 6. The electromagnet 61 has a core 611 and a coil 612. The core 611 has a winding portion 611A, a first widening portion 611B, and a second widening portion 611C. The winding portion 611A is the central part of the core 611 in the Y direction and extends in the Y direction. The winding portion 611A has a rectangular cross-sectional shape along the XZ plane, and its outer circumferential surface is formed by four surfaces with the positive X direction, negative X 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.

[0023] The first widening portion 611B is formed at the Y-negative end of the winding portion 611A, projecting on both sides in the X direction relative to the winding portion 611A. The second widening portion 611C is formed at the Y-positive end of the winding portion 611A, projecting on both sides in the X direction relative to the winding portion 611A. Both the first widening portion 611B and the second widening portion 611C have a rectangular cross-sectional shape along the XZ plane and have four faces with the X-positive side, X-negative side, Z-positive side, and Z-negative side as normal directions. In other words, the first widening portion 611B and the second widening portion 611C have a pair of end faces that project by the same amount relative to the winding portion 611A along the X direction.

[0024] The electromagnet 61 generates a magnetic field M (see Figure 2) passing through the center of the coil 612 when current flows through the wires constituting the coil 612, thereby energizing it. The magnetic field generated by the coil 612 is further strengthened by the core 611.

[0025] The first movable plate 62 and the second movable plate 63 are members formed from a magnetic material. The first movable plate 62 is positioned on the positive X-direction side of the electromagnet 61, and the second movable plate 63 is positioned on the negative X-direction side of the electromagnet 61. The first movable plate 62 and the second movable plate 63 are formed to the same shape and are positioned opposite each other in the X-direction with the electromagnet 61 in between.

[0026] A pair of first coil springs 66A and 66B are positioned between the electromagnet 61 and the first movable plate 62 such that the X-direction is the direction of expansion and contraction. The pair of first coil springs 66A and 66B have the same natural length. In the example shown in Figure 1, the pair of first coil springs 66A and 66B are positioned to contact the X-positive end face of the first widening portion 611B of the electromagnet 61 and the X-positive end face of the second widening portion 611C, respectively. With the first coil springs 66A and 66B interposed between the electromagnet 61 and the first movable plate 62 in this way, when the electromagnet 61 is not operating, the first movable plate 62 is positioned at a distance of the natural length of the first coil springs 66A and 66B from the electromagnet 61 in the X-positive direction. In the following description, this position will be referred to as the reference position A1 of the first movable plate 62. In Figure 1, this reference position A1 is shown by a dashed line.

[0027] A pair of second coil springs 67A and 67B are positioned between the electromagnet 61 and the second movable plate 63 such that their extension and contraction directions are in the X direction. The pair of second coil springs 67A and 67B have the same natural length. In the example shown in Figure 1, the pair of second coil springs 67A and 67B are positioned to contact the X-negative end face of the first widening portion 611B of the electromagnet 61 and the X-negative end face of the second widening portion 611C, respectively. With the second coil springs 67A and 67B interposed between the electromagnet 61 and the second movable plate 63 in this way, when the electromagnet 61 is not operating, the second movable plate 63 is positioned at a distance of the natural length of the second coil springs 67A and 67B from the electromagnet 61 in the X-negative direction. In the following description, this position will be referred to as the reference position A2 of the second movable plate 63. In Figure 1, this reference position A2 is shown by a dashed line.

[0028] 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 M (see Figure 2) generated when the electromagnet 61 is energized. At this time, the pair of first coil springs 66A and 66B and the pair of second coil springs 67A and 67B are both contracted and biased in directions away from the electromagnet 61 (positive X direction and negative X direction). 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 forces D1 and D2 (see Figure 2, etc.) added by the pair of first coil springs 66A and 66B and the pair of second coil springs 67A and 67B. In other words, the first movable plate 62 and the second movable plate 63 can perform vibrational motion in the X direction by switching the energization of the electromagnet 61 between energization and de-energization.

[0029] As shown in Figure 1, the first movable plate 62 is provided with a pair of through holes 62A and 62B that penetrate along the X direction. First guide shafts 64A and 64B, which extend in the X direction, are inserted through these through holes 62A and 62B, respectively. This makes it easier for the first movable plate 62 to move along the X direction. The first guide shafts 64A and 64B are connected and fixed to the fixed part described above, for example.

[0030] Furthermore, it is preferable that the pair of through holes 62A and 62B and the pair of first guide shafts 64A and 64B are positioned approximately equidistant from the center position of the first movable plate 62 in the Y direction. In the example shown in Figure 1, the pair of through holes 62A and 62B and the pair of first guide shafts 64A and 64B are positioned opposite the X-positive end face of the first widening portion 611B of the electromagnet 61 and the X-positive end face of the second widening portion 611C, respectively. This allows the first movable plate 62 to be guided in a balanced manner along the Y-extension direction when it moves in the X direction, making it less likely for the first movable plate 62 to tilt with respect to the Y direction and easier for it to slide along the X direction.

[0031] Similarly, as shown in Figure 1, the second movable plate 63 is provided with a pair of through holes 63A and 63B that penetrate along the X direction. Second guide shafts 65A and 65B, which extend in the X direction, are inserted through these through holes 63A and 63B, respectively. This makes it easier for the second movable plate 63 to move along the X direction. The second guide shafts 65A and 65B are also connected and fixed to the aforementioned fixed part, for example.

[0032] Furthermore, it is preferable that the pair of through holes 63A and 63B and the pair of second guide shafts 65A and 65B are positioned approximately equidistant from the center position of the second movable plate 63 in the Y direction. In the example shown in Figure 1, the pair of through holes 63A and 63B and the pair of second guide shafts 65A and 65B are positioned opposite the X-negative end face of the first widening portion 611B of the electromagnet 61 and the X-negative end face of the second widening portion 611C, respectively. This allows the second movable plate 63 to be guided in a balanced manner along the Y-extension direction when it moves in the X direction, making it less likely for the second movable plate 63 to tilt with respect to the Y direction and easier for it to slide along the X direction.

[0033] The X-positive side of the first movable plate 62 is positioned opposite the X-negative side of the first pump chamber 7. A first piston 71 is installed on the X-positive side of the first movable plate 62 so as to protrude in the X-positive direction. The tip of the first piston 71 on the X-positive side is inserted into the first pump chamber 7 and is installed so as to be slidable within the first pump chamber 7 in response to vibrations of the first movable plate 62 in the X direction. The volume of the first pump chamber 7 can be changed by the sliding of the first piston 71 in this manner.

[0034] Although not shown in Figure 1, the first pump chamber 7 incorporates a well-known intake valve and discharge valve. When the first piston 71 enters the first pump chamber 7 and reduces its volume, the intake valve closes and the discharge valve opens. As a result, the fluid W in the first pump chamber 7 is discharged downstream through the discharge valve. Similarly, when the first piston 71 moves in the negative X direction and increases the volume of the first pump chamber 7, the intake valve opens and the discharge valve closes. As a result, the fluid from the upstream side is drawn into the first pump chamber 7 through the intake valve.

[0035] Similarly, the X-negative side of the second movable plate 63 is positioned opposite the X-positive side of the second pump chamber 8. A second piston 81 is installed on the X-negative side of the second movable plate 63 so as to protrude in the X-negative direction. The X-negative tip of the second piston 81 is inserted into the second pump chamber 8 and is installed to slide within the second pump chamber 8 in response to vibrations of the second movable plate 63 in the X direction. The volume of the second pump chamber 8 can be changed by the sliding of the second piston 81 in this manner.

[0036] Furthermore, although not shown in Figure 1, the second pump chamber 8 also contains a well-known intake valve and discharge valve. When the second piston 81 enters the second pump chamber 8 and reduces its volume, the intake valve closes and the discharge valve opens. As a result, the fluid W in the second pump chamber 8 is discharged downstream through the discharge valve. Similarly, when the second piston 81 moves in the negative X direction and increases the volume of the second pump chamber 8, the intake valve opens and the discharge valve closes. As a result, the fluid from the upstream side is drawn into the second pump chamber 8 through the intake valve.

[0037] Furthermore, in this embodiment, the resonant actuator 6 comprises a pair of first magnets 9A and 9B related to the first movable plate 62, and a pair of second magnets 10A and 10B. The pair of first magnets 9A and 9B are provided at both ends of the first movable plate 62 in a direction perpendicular to the vibration direction, i.e., in the Y direction. In the example of Figure 1, one first magnet 9A is provided at the Y-positive end of the first movable plate 62, and the other first magnet 9B is provided at the Y-negative end of the first movable plate 62. The pair of second magnets 10A and 10B are provided at a position in the fixed part opposite to the first magnets 9A and 9B. Here, the fixed part is a member that is directly or indirectly fixed to the housing 2 of the pump 1 so that it cannot move due to vibration, such as the first movable plate 62, and in the example of Figure 1, it is the suction-side bypass 51 and the discharge-side bypass 52 of the flow path 5. In the example shown in Figure 1, one second magnet 10A is provided on the Y-negative side of the intake-side bypass 51, and the other second magnet 10B is provided on the Y-positive side of the discharge-side bypass 52. Furthermore, the pair of second magnets 10A and 10B are positioned on the side of the first movable plate 62 that is closer to the electromagnet 61 than the reference position A1 (i.e., the X-negative side), and are positioned to face each of the first magnets 9A and 9B when the first movable plate 62 is closest to the electromagnet 61 when the electromagnet 61 is operating.

[0038] Similarly, the resonant actuator 6 comprises a pair of first magnets 9C and 9D related to the second movable plate 63, and a pair of second magnets 10C and 10D. The pair of first magnets 9C and 9D are provided at both ends of the second movable plate 63 in a direction perpendicular to the vibration direction, i.e., in the Y direction. In the example of Figure 1, one first magnet 9C is provided at the Y-positive end of the second movable plate 63, and the other first magnet 9D is provided at the Y-negative end of the second movable plate 63. The pair of second magnets 10C and 10D are provided at a position in the fixed part opposite to the first magnets 9C and 9D. In the example of Figure 1, one second magnet 10C is provided on the Y-negative side surface of the intake-side bypass 51, and the other second magnet 10D is provided on the Y-positive side surface of the discharge-side bypass 52. Furthermore, the pair of second magnets 10C and 10D are positioned on the side of the first movable plate 62 that is closer to the electromagnet 61 than the reference position A1 (i.e., on the X-negative direction side), and are positioned to face each of the first magnets 9C and 9D when the second movable plate 63 is closest to the electromagnet 61 when the electromagnet 61 is operating.

[0039] Furthermore, in the example of magnet arrangement shown in Figure 1, the first magnet 9A provided at the Y-positive end of the first movable plate 62 has an N pole on the side facing the second magnet 10A, and the second magnet 10A positioned opposite the first magnet 9A has an S pole on the side facing the first magnet 9A (see Figure 2, etc.). Similarly, the first magnet 9B provided at the Y-negative end of the first movable plate 62 has an S pole on the side facing the second magnet 10B, and the second magnet 10B positioned opposite the first magnet 9B has an N pole on the side facing the first magnet 9B. Similarly, the first magnet 9C provided at the Y-positive end of the second movable plate 63 has an N pole on the side facing the second magnet 10C, and the second magnet 10C positioned opposite the first magnet 9C has an S pole on the side facing the first magnet 9C. Similarly, the first magnet 9D provided at the Y-negative end of the second movable plate 63 has a south pole on the side facing the second magnet 10D, and the second magnet 10D positioned opposite the first magnet 9D has a north pole on the side facing the first magnet 9D. In other words, in this embodiment, each pair of opposing first magnets 9A to 9D and second magnets 10A to 10D is composed of a north pole and a south pole.

[0040] The operation of the pump 1 and resonant actuator 6 according to this embodiment will be explained with reference to Figures 2 to 4. Note that in Figures 2 to 4, the illustration is limited to the area around the resonant actuator 6 of the pump 1, and the housing 2 and the intake side bypass 51 and discharge side bypass 52 of the flow path 5 are omitted from the illustration.

[0041] Figure 2 shows the first stage of operation of the pump 1 and resonant actuator 6 according to the embodiment. The premise for the first stage is that, as shown in Figure 1, the resonant actuator 6 is in a steady state, that is, the electromagnet 61 is in a non-operating state, and the first movable plate 62 and the second movable plate 63 are stationary at reference positions A1 and A2, respectively.

[0042] From this steady state, as shown in Figure 2, when the coil 612 of the electromagnet 61 is energized, a magnetic field M is generated passing through the center of the coil 612. The magnetic field M 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 2, a magnetic field M is generated inside the winding portion 611A, directed toward the positive Y direction.

[0043] The magnetic field M generated in this way branches out in the positive X direction and the negative X direction along the protruding direction to the second widening section 611C located on the positive Y direction side of the core 611. Next, it flows in the negative Y direction through the interior of the first movable plate 62 and the second movable plate 63, which are facing each other at the end faces on both sides of the second widening section 611C in the X direction. Then, from the end faces on both sides of the first widening section 611B located on the negative Y direction side of the winding section 611A, it flows through the interior of the first widening section 611B toward the central part in the X direction, merges, and then flows back into the winding section 611A. In other words, the magnetic field M illustrated in Figure 2, when viewed from the positive Z direction, flows in a clockwise direction on the first movable plate 62 side and in a counterclockwise direction on the second movable plate 63 side.

[0044] Due to the generation of such a magnetic field M, as indicated by arrow B1 in FIG. 2, the first movable plate 62 is attracted by the electromagnet 61 and moves toward the X negative direction side. Similarly, as indicated by arrow B2 in FIG. 2, the second movable plate 63 is attracted by the electromagnet 61 and moves toward the X positive direction side. At this time, the through-holes 62A and 62B provided in the first movable plate 62 and the first guide shafts 64A and 64B inserted into these through-holes 62A and 62B enable smooth parallel movement of the first movable plate 62 toward the X negative direction side. Similarly, the through-holes 63A and 63B provided in the second movable plate 63 and the second guide shafts 65A and 65B inserted into these through-holes 63A and 63B enable smooth parallel movement of the second movable plate 63 toward the X positive direction side.

[0045] Due to such movement of the first movable plate 62 and the second movable plate 63 toward the side attracted to the electromagnet 61, in the first pump chamber 7, the first piston 71 slides toward the X negative direction side as indicated by arrow C1. This increases the volume of the first pump chamber 7, and the fluid W is sucked into the first pump chamber 7 from the upstream side of the flow path 5. Similarly, in the second pump chamber 8, the second piston 81 slides toward the X positive direction side as indicated by arrow C2. This increases the volume of the second pump chamber 8, and the fluid W is sucked into the second pump chamber 8 from the upstream side of the flow path 5.

[0046] Furthermore, as the first movable plate 62 and the second movable plate 63 move toward the side attracted to the electromagnet 61, the coil springs 66A and 66B positioned between the electromagnet 61 and the first movable plate 62 contract. Here, the electromagnet 61 is fixed to the fixed part. In other words, the X-direction negative ends of the coil springs 66A and 66B are restricted from moving in the X direction by the electromagnet 61 (in the example of Figure 1, the X-positive end faces of the first widening section 611B and the second widening section 611C). Therefore, as shown by arrow D1 in Figure 1, the coil springs 66A and 66B are biased toward the X-positive direction. Similarly, the coil springs 67A and 67B positioned between the electromagnet 61 and the second movable plate 63 also contract. The X-positive end faces of the coil springs 67A and 67B are restricted from moving in the X direction by the electromagnet 61 (the X-negative end faces of the first widening portion 611B and the second widening portion 611C in the example of Figure 1). As a result, as shown by arrow D2 in Figure 1, the coil springs 67A and 67B are biased toward the X-positive direction.

[0047] Figure 3 shows the second stage of operation of the pump 1 and resonant actuator 6 according to the embodiment. In the second stage, the coil 612 of the electromagnet 61 is switched from the energized state shown in Figure 2 to the de-energized state. As a result, the magnetic field M that was generated around the electromagnet 61 disappears.

[0048] When the magnetic field M disappears, the attractive force that the first movable plate 62 and the second movable plate 63 have received from the electromagnet 61 also disappears. Therefore, the coil springs 66A and 66B operate to elastically recover under the biasing force D1 in the positive X-direction generated in the coil springs 66A and 66B, which is indicated by the dotted arrow in FIG. 1. In response to this operation, the first movable plate 62 also moves toward the positive X-direction side. However, since the attractive force that was balanced with the biasing force D1 disappears, neither the first movable plate 62 nor the coil springs 66A and 66B stop at the reference position A1, and they further move toward the positive X-direction side. Finally, as indicated by arrow E1 in FIG. 3, the first movable plate and the coil springs move away from the electromagnet 61 to the positive X-direction side from the reference position A1 by a distance approximately equal to the movement amount caused by the attraction of the electromagnet 61. Similarly, as indicated by arrow E2 in FIG. 3, the second movable plate 63 and the coil springs 67A and 67B also move away from the electromagnet 61 to the negative X-direction side from the reference position A2 under the biasing force D2 in the negative X-direction generated in the coil springs 67A and 67B.

[0049] Due to such movement of the first movable plate 62 and the second movable plate 63 toward the side away from the electromagnet 61, in the first pump chamber 7, the first piston 71 slides toward the positive X-direction side as indicated by arrow F1. As a result, the volume of the first pump chamber 7 is reduced, and the fluid W in the first pump chamber 7 is discharged to the downstream side of the flow path 5. Similarly, in the second pump chamber 8, the second piston 81 slides toward the negative X-direction side as indicated by arrow F2. As a result, the volume of the second pump chamber 8 is reduced, and the fluid in the second pump chamber 8 is discharged to the downstream side of the flow path 5.

[0050] FIG. 4 is a diagram showing the third stage of the operation of the pump 1 and the resonant actuator 6 according to the embodiment. In the third stage, the coil 612 of the electromagnet 61 is switched from the non-energized state shown in FIG. 3 to the energized state again. Accordingly, a magnetic field M similar to that in FIG. 2 is generated again around the electromagnet 61.

[0051] However, the third stage differs from the first stage in FIG. 2 in that both the first movable plate 62 and the second movable plate 63 are located at the positions farthest away from the electromagnet 61. Therefore, the attractive force that the first movable plate 62 and the second movable plate 63 receive from the electromagnet 61 via the magnetic field M is reduced compared to that in the first stage.

[0052] Here, as shown in Figure 4, in the third stage, both the first movable plate 62 and the second movable plate 63 are at their furthest positions from the electromagnet 61. Therefore, the first magnets 9A and 9B installed on the first movable plate 62 are located on the positive X side of the reference position A1. In other words, the first magnets 9A and 9B are at their furthest positions from the second magnets 10A and 10B, respectively, in the X direction. Similarly, the first magnets 9C and 9D installed on the second movable plate 63 are located on the negative X side of the reference position A2. In other words, the first magnets 9C and 9D are also at their furthest positions from the second magnets 10C and 10D, respectively, in the X direction.

[0053] As described above, in this embodiment, the pairs of first magnets 9A to 9D and second magnets 10A to 10D, which are positioned opposite each other, are composed of an N pole and an S pole, respectively. Therefore, when they are in the positional relationship shown in the third stage, a magnetic force is generated between the pairs of first magnets 9A to 9D and second magnets 10A to 10D that causes them to move closer to each other. In this embodiment, the second magnets 10A to 10D are fixed to the fixed part, and the first magnets 9A to 9D are installed to be movable in the X direction together with the first movable plate 62 and the second movable plate 63. Therefore, as shown by the dotted arrows H1 to H4 in Figure 4, magnetic forces H1 to H4 are generated in the direction that causes the first magnets 9A to 9D to move closer to the second magnets 10A to 10D.

[0054] More specifically, in the first movable plate 62, magnetic forces H1 and H2 are generated in the direction in which the first magnets 9A and 9B approach the second magnets 10A and 10B, respectively, i.e., in the negative X direction. Similarly, in the second movable plate 63, magnetic forces H3 and H4 are generated in the direction in which the first magnets 9C and 9D approach the second magnets 10C and 10D, respectively, i.e., in the positive X direction. These directions of approach are the same as the directions in which the first movable plate 62 and the second movable plate 63 approach the electromagnet 61, respectively.

[0055] Therefore, in this embodiment, the magnetic forces H1 to H4 generated in this way can compensate for the decrease in the attractive force that the first movable plate 62 and the second movable plate 63 receive from the electromagnet 61 due to the magnetic field M. As a result, even when the first movable plate 62 and the second movable plate 63 are positioned furthest from the electromagnet 61, it is possible to apply the same external force to the first movable plate 62 and the second movable plate 63 as in the first stage. This makes it possible to move the first movable plate 62 and the second movable plate 63 again in a direction closer to the electromagnet 61 under the same conditions as in the first stage, as shown by arrows G1 and G2 in Figure 4.

[0056] As described above, the resonant actuator 6 according to this embodiment includes an electromagnet 61, a first movable plate 62 and a second movable plate 63 (hereinafter sometimes collectively referred to as "movable parts 62, 63") which are movable parts installed to move toward and away from the electromagnet 61 in a predetermined direction (X direction in Figures 1 to 4) in accordance with the magnetic field M generated by the electromagnet 61, an intake-side bypass 51 and an exhaust-side bypass 52 of the flow path 5 as an example of a fixed part for fixing the electromagnet 61, a pair of first magnets 9A, 9B provided at both ends of the first movable plate 62 in a direction perpendicular to the predetermined direction (Y direction in Figures 1 to 4), a pair of second magnets 10A, 10B provided at a position in the fixed part opposite to the first magnets 9A, 9B, a pair of first magnets 9C, 9D provided at both ends of the second movable plate 63 in a direction perpendicular to the predetermined direction, and a pair of second magnets 10C, 10D provided at a position in the fixed part opposite to the first magnets 9C, 9D. The second magnets 10A to 10D are arranged so as to generate magnetic forces H1 to H4 in a direction approaching the electromagnet 61 when the movable parts 62 and 63 are at their furthest distance from the electromagnet 61, between them and the first magnets 9A to 9D.

[0057] With this configuration, even if the movable parts 62 and 63 move away from the electromagnet 61 and the attractive force they receive from the electromagnet 61 due to the magnetic field M is relatively reduced, this reduction can be compensated for by the magnetic forces H1 to H4 generated between the first magnets 9A to 9D and the second magnets 10A to 10D. As a result, the attractive force applied to the movable parts 62 and 63 toward the electromagnet 61 can be stabilized regardless of the position of the movable parts 62 and 63 relative to the electromagnet 61.

[0058] Furthermore, neodymium magnets, ferrite magnets, and other types of magnets can be appropriately applied as the first magnets 9A to 9D and the second magnets 10A to 10D, depending on the desired magnitude of the attractive force. In addition, the areas of the first magnets 9A to 9D and the second magnets 10A to 10D can be appropriately changed according to the desired magnitude of the attractive force.

[0059] Furthermore, in the resonant actuator 6 according to this embodiment, the first magnets 9A to 9D and the second magnets 10A to 10D, which are arranged opposite each other, are a pair of north poles and south poles, and it is preferable that the second magnets 10A to 10D are positioned to face the first magnets 9A to 9D at the reference positions A1 and A2 of the movable parts 62 and 63 when the electromagnet 61 is not operating, or at a position closer to the electromagnet 61 than the reference positions A1 and A2.

[0060] This configuration makes it possible to reliably separate the first magnets 9A to 9D provided on the movable parts 62 and 63 from the second magnets 10A to 10D along the direction of movement (X direction) of the movable parts 62 and 63 when the movable parts 62 and 63 are at their furthest distance from the electromagnet 61. As a result, it is possible to more reliably generate magnetic forces H1 to H4 in the direction of approaching the electromagnet 61 between the first magnets 9A to 9D and the second magnets 10A to 10D.

[0061] Furthermore, as illustrated in Figures 1 to 4, it is even more preferable that the second magnets 10A to 10D are positioned directly opposite the first magnets 9A to 9D at the position where the movable parts 62 and 63 are closest to the electromagnet 61 when the electromagnet 61 is operating. This configuration makes it possible to more reliably generate magnetic forces H1 to H4 in the direction approaching the electromagnet 61 between the first magnets 9A to 9D and the second magnets 10A to 10D.

[0062] Furthermore, it is preferable that the first magnets 9A to 9D are provided in recesses formed at both ends of the movable parts 62 and 63 in the Y direction, the recesses being the same thickness as or greater than the thickness of the first magnets 9A to 9D in the Y direction. This prevents an increase in the Y-direction dimensions of the movable parts 62 and 63 even when the first magnets 9A to 9D are provided, thereby suppressing an increase in the size of the resonant actuator 6.

[0063] However, if first magnets 9A to 9D are incorporated into the movable parts 62 and 63 in order to increase the magnetic attraction force of the coil 612 of the electromagnet 61, a magnetic circuit may be formed between the first magnets 9A and 9B in the first movable plate 62, and a magnetic circuit may be formed between the first magnets 9C and 9D in the second movable plate 63, and these two magnetic circuits may overlap as they follow the same route as the magnetic circuit M of the coil 612. As a result, the core 611 of the electromagnet 61 is more prone to magnetic saturation compared to the case where only the coil 612 is provided without the first magnets 9A to 9D. To address this problem, in this embodiment, by making each second magnet 10A to 10D, which is positioned opposite each first magnet 9A to 9D, have different poles than the first magnets 9A to 9D, a magnetic circuit can be formed between the first magnets 9A to 9D and the second magnets 10A to 10D. In other words, it is possible to prevent the formation of a magnetic circuit between the first magnets 9A and 9B on the first movable plate 62, and the formation of a magnetic circuit between the first magnets 9C and 9D on the second movable plate 63. As a result, the magnetic circuit of the magnets can be routed separately from the magnetic circuit M of the coil 612, making it possible to create a structure in which the core 611 of the electromagnet 61 is less prone to magnetic saturation.

[0064] Furthermore, in the resonant actuator 6 according to this embodiment, it is preferable that the first movable plate 62 and the second movable plate 63, which are movable parts, be provided as a pair on both sides of the electromagnet 61 in a predetermined direction of movement (X direction). With this configuration, the first movable plate 62 and the second movable plate 63 are arranged opposite each other in the direction of translational motion, thereby suppressing the transmission of vibrations generated from the movable parts 62 and 63 to the outside.

[0065] Furthermore, in the resonant actuator 6 according to this embodiment, it is preferable that the first magnets 9A to 9D and the second magnets 10A to 10D, which are arranged opposite each other, are not in contact with each other. This configuration prevents the first magnets 9A to 9D and the second magnets 10A to 10D from being attracted to each other by the magnetic forces H1 to H4 generated between them, thereby preventing the movement of the first movable plate 62 and the second movable plate 63 from being hindered. This stabilizes the attractive force towards the electromagnet 61 attached to the first movable plate 62 and the second movable plate 63, and allows the movement of the first movable plate 62 and the second movable plate 63 to be smooth.

[0066] A first modified example of the embodiment will be described with reference to Figures 5 to 7. Figures 5 to 7 show the first to third stages of operation of the pump 1 and resonant actuator 6A according to the first modified example. The outlines of each stage in Figures 5 to 7 are the same as those in Figures 2 to 4. In the first modified example, the poles and arrangement of the magnets are different.

[0067] As shown in Figures 5 to 7, the resonant actuator 6A according to the first modified example differs from the above embodiment in that the first magnets 9A to 9D and the second magnets 11A to 11D, which are arranged opposite each other, are both pairs of N poles or S poles. Also differs from the above embodiment in that the second magnets 11A to 11D are positioned to face the first magnets 9A to 9D when the electromagnet 61 is operating and the movable parts 62 and 63 are furthest away from the electromagnet 61.

[0068] In the arrangement of magnets in the first modified example, in the third stage shown in Figure 7, the first magnets 9A to 9D are directly facing the second magnets 11A to 11D in the X direction and are in the closest position to them. In the first modified example, since the first magnets 9A to 9D and the second magnets 11A to 11D, which are arranged opposite each other, have the same poles, in the third stage, a magnetic force is generated between the pairs of first magnets 9A to 9D and second magnets 10A to 10D that causes them to move apart from each other.

[0069] In the first modified example, the second magnets 11A to 11D are fixed to the fixed part, and the first magnets 9A to 9D are installed to be movable in the X direction together with the first movable plate 62 and the second movable plate 63. As a result, as shown by the dotted arrows J1 to J4 in Figure 7, magnetic forces J1 to J4 are generated in the direction that moves the first magnets 9A to 9D away from the second magnets 11A to 11D.

[0070] More specifically, in the first movable plate 62, magnetic forces J1 and J2 are generated in the direction that moves the first magnets 9A and 9B away from the second magnets 11A and 11B, respectively, i.e., in the negative X direction. Similarly, in the second movable plate 63, magnetic forces J3 and J4 are generated in the direction that moves the first magnets 9C and 9D away from the second magnets 11C and 11D, respectively, i.e., in the positive X direction. These directions of approach are the same as the directions in which the first movable plate 62 and the second movable plate 63 approach the electromagnet 61, respectively.

[0071] Therefore, even in the first modified example, the magnetic forces J1 to J4 generated in this way can compensate for the decrease in the attractive force that the first movable plate 62 and the second movable plate 63 receive from the electromagnet 61 due to the magnetic field M. For this reason, even when the first movable plate 62 and the second movable plate 63 are positioned furthest from the electromagnet 61, it is possible to apply the same external force to the first movable plate 62 and the second movable plate 63 as in the first stage shown in Figure 5. As a result, as shown by arrows I1 and I2 in Figure 7, the first movable plate 62 and the second movable plate 63 can be moved again in a direction closer to the electromagnet 61 under the same conditions as in the first stage.

[0072] A second modified example of the embodiment will be described with reference to Figure 8. Figure 8 is a plan view showing the schematic configuration of the resonant actuator 6B according to the second modified example. The overview of Figure 8 is the same as that of Figure 2, etc., and the non-operating state shown in Figure 1 is illustrated. In the second modified example, the arrangement of the second magnets 12A to 12D differs from that of the above embodiment. Also, the resonant actuator 6B differs from the above embodiment in that it does not have coil springs 66A, 66B, 67A, and 67B.

[0073] As shown in Figure 8, in the resonant actuator 6B according to the second modified example, the second magnets 12A and 12B are positioned on the reference position A1, so that they are positioned directly opposite the first magnets 9A and 9B at the reference position A1. Similarly, the second magnets 12C and 12D are positioned on the reference position A2, so that they are positioned directly opposite the first magnets 9C and 9D at the reference position A2.

[0074] The second magnet 12A, positioned opposite the first magnet 9A, has a south pole on the side facing the first magnet 9A, similar to the second magnet 10A in the embodiment. The second magnet 12B, positioned opposite the first magnet 9B, has a north pole on the side facing the first magnet 9B, similar to the second magnet 10B in the embodiment. The second magnet 12C, positioned opposite the first magnet 9C, has a south pole on the side facing the first magnet 9C, similar to the second magnet 10C in the embodiment. The second magnet 12D, positioned opposite the first magnet 9D, has a north pole on the side facing the first magnet 9D, similar to the second magnet 10D in the embodiment. In other words, in the second modification as well, similar to the above embodiment, each pair of opposing first magnets 9A to 9D and second magnets 12A to 12D is composed of a north pole and a south pole.

[0075] In the second modified resonant actuator 6B, current is supplied to the coil 612, and the magnetic attraction force pulls the first movable plate 62 toward the core 611 (negative X direction). At this time, the first magnets 9A and 9B move toward the negative X direction relative to the second magnets 12A and 12B. Therefore, when the current is cut off after the first movable plate 62 has been pulled toward the core 611, the first movable plate 62 moves toward the positive X direction due to the magnetic force generated between the first magnets 9A and 9B and the second magnets 12A and 12B.

[0076] Then, when the first movable plate 62 moves further in the positive X direction beyond its initial reference position A1 due to inertia, the first magnets 9A and 9B move in the positive X direction relative to the second magnets 12A and 12B. As a result, the magnetic force generated between the first magnets 9A and 9B and the second magnets 12A and 12B acts to move the first movable plate 62 in the negative X direction, causing it to return to the reference position A1. Simultaneously, if current is supplied to the coil 612, the first movable plate 62 will repeat the same operation.

[0077] Similarly, in the resonant actuator 6B according to the second modified example, the coil 612 is energized, and the second movable plate 63 is attracted towards the core 611 (positive X direction) by magnetic attraction force. At this time, the first magnets 9C and 9D move towards the positive X direction relative to the second magnets 12C and 12D. Therefore, when the power is turned off after the second movable plate 63 has been attracted towards the core 611, the second movable plate 63 moves towards the negative X direction due to the magnetic force generated between the first magnets 9C and 9D and the second magnets 12C and 12D.

[0078] Then, when the second movable plate 63 moves further in the negative X direction beyond its initial reference position A2 due to inertia, the first magnets 9C and 9D move in the negative X direction relative to the second magnets 12C and 12D. As a result, the magnetic force generated between the first magnets 9C and 9D and the second magnets 12C and 12D acts to move the second movable plate 63 in the positive X direction, returning it to the reference position A2. Simultaneously, if current is supplied to the coil 612, the second movable plate 63 will repeat the same operation.

[0079] In the second modified example, the first movable plate 62 and the second movable plate 63 can be made to behave as described above by utilizing the switching of current supply from the electromagnet 61 to the coil 612 and the magnetic force between the first magnets 9A to 9D and the second magnets 12A to 12D. For this reason, the second modified example does not require the coil springs 66A, 66B, 67A, and 67B as in the above embodiment and the first modified example.

[0080] 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, their arrangement, conditions, shapes, etc., of each of the aforementioned specific examples are not limited to those illustrated 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.

[0081] In the above embodiment and the first and second modifications, a configuration using a first piston 71 and a second piston 81 was exemplified as an example of a "volume changing member provided in the movable part (first movable plate 62 and second movable plate 63) that changes the volume of each pump chamber 7 and 8 so that the volume of the first pump chamber 7 and the second pump chamber 8 increases and decreases in accordance with the movement of the movable part in a predetermined direction (X direction)". However, elements other than pistons may also be used. Examples of elements other than pistons for the volume changing member include diaphragms and bellows.

[0082] Furthermore, in the above embodiments and the first and second modifications, the resonant actuators 6, 6A, and 6B are exemplified as having a configuration in which a pair of movable parts, the first movable plate 62 and the second movable plate 63, are provided on both sides of the electromagnet 61 in a predetermined direction of movement (X direction). However, it is also possible to have a configuration in which only one of the pair of movable parts is provided. In other words, it is possible to have only one of the set of the first movable plate 62, the first piston 71, and the first pump chamber 7, or the set of the second movable plate 63, the second piston 81, and the second pump chamber 8.

[0083] Furthermore, in the above embodiment and the first modified example, the resonant actuators 6 and 6A are exemplified as being equipped with first coil springs 66A and 66B and second coil springs 67A and 67B, but they may be replaced with elements that can apply an external force to the first movable plate 62 and the second movable plate 63 in a direction away from the electromagnet 61. Examples of such elements include elastic elements other than coil springs, such as rubber. Also, in the above embodiment and the first modified example, the first coil springs 66A and 66B are exemplified as being arranged between the electromagnet 61 and the first movable plate 62, and the second coil springs 67A and 67B are exemplified as being arranged between the electromagnet 61 and the second movable plate 63, but instead, the first coil springs 66A and 66B may be exemplified as being arranged between the first movable plate 62 and the first pump chamber 7, and the second coil springs 67A and 67B may be exemplified as being arranged between the second movable plate 63 and the second pump chamber 8.

[0084] This international application claims priority under Japanese Patent Application No. 2025-056824, filed on 28 March 2025, and the entire contents of No. 2025-056824 are incorporated herein by reference.

[0085] 1 Pump 6, 6A, 6B Resonant actuator 7 First pump chamber 8 Second pump chamber 9A, 9B, 9C, 9D First magnet 10A, 10B, 10C, 10D, 11A, 11B, 11C, 11D, 12A, 12B, 12C, 12D Second magnet 51 Intake side bypass (fixed part) 52 Discharge side bypass (fixed part) 61 Electromagnet 62 First movable plate (movable part) 63 Second movable plate (movable part) 71 First piston (volume changing member) 81 Second piston (volume changing member) A1 Reference position of the first movable plate A2 Reference position of the second movable plate

Claims

Electromagnets and, A movable part is installed so as to be movable in a predetermined direction that approaches and moves away from the electromagnet in response to the magnetic field generated by the electromagnet, A fixing part for fixing the electromagnet, A pair of first magnets are provided at both ends of the movable part in a direction perpendicular to the predetermined direction, A pair of second magnets are provided in the fixing portion at a position opposite to the first magnet, Equipped with, The pair of second magnets are arranged such that when the movable part is at its furthest distance from the electromagnet, they generate a magnetic force between themselves and the pair of first magnets in a direction approaching the electromagnet. Resonant actuator. 　 The first magnet and the second magnet, which are arranged opposite each other, are a pair of north poles and south poles, The second magnet is positioned to face the first magnet directly at the reference position of the movable part when the electromagnet is not operating, or at a position closer to the electromagnet than the reference position. The resonant actuator according to claim 1. 　 The second magnet is positioned so as to be directly opposite the first magnet when the movable part is closest to the electromagnet during operation. The resonant actuator according to claim 2. 　 The first magnet and the second magnet, which are arranged opposite each other, are both a pair of north poles or south poles. The second magnet is positioned so as to face the first magnet when the movable part is furthest away from the electromagnet during operation. The resonant actuator according to claim 1. 　 The movable parts are provided in pairs on both sides of the electromagnet in the predetermined direction. The resonant actuator according to claim 1. 　 The first magnet and the second magnet, which are positioned opposite each other, are arranged so as not to be in contact with each other. The resonant actuator according to claim 1. 　 The resonant actuator according to claim 1, A pump chamber is provided on the fluid passage, A volume changing member is provided on the movable part and changes the volume of the pump chamber so as the movable part moves in the predetermined direction, thereby increasing and decreasing the volume of the pump chamber. A pump equipped with the following features.

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