JP2008088904A - Piezoelectric pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric pump which can be easily reduced in size. <P>SOLUTION: The piezoelectric pump 1 is equipped with: a cylindrical body 5 forming a pump chamber 16 therein; a pair of check valves 7, 9 provided in the cylindrical body 5 and positioned separately on both ends of the pump chamber 16; a long laminated piezoelectric element 11 supported in a cantilevered state; and a long pressing member for applying pressing force to the cylindrical body 5 by using deforming action of the laminated piezoelectric element 11. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a piezoelectric pump.

An example of a piezoelectric pump using a piezoelectric element is disclosed in Patent Document 1. In this piezoelectric pump, a pump chamber is formed by means for forming a chamber such as a circular thin plate diaphragm and a casing. The casing is connected to a tubular portion that forms a suction flow path and a tubular portion that forms a discharge flow path. The connection end to the pump chamber in each tubular portion cooperates with the valve membrane to provide a check valve function. In such a configuration, by displacing the piezoelectric element and pressing almost the center of the diaphragm, the fluid in the pump chamber is discharged into the discharge passage, and the fluid is sucked into the pump chamber from the suction passage.
JP 2003-13861 A

  Piezoelectric pumps are expected to be applied to electronic devices and medical devices, and downsizing is desired. However, in the conventional piezoelectric pump described above, the discharge pressure is obtained by pressing the diaphragm. Therefore, if a sufficient discharge amount is to be obtained, the diaphragm is enlarged, and accordingly, the pump chamber also extends the diaphragm. The size of the pump must be reduced.

  The present invention has been made in view of the above, and an object thereof is to provide a piezoelectric pump that can be easily downsized.

  In order to solve the above-described problems, a piezoelectric pump according to the present invention includes a cylindrical body in which a pump chamber is formed, a pair of check valves that are distributed and positioned on both sides of the pump chamber, and a cantilever mode. And a long pressing member that applies a pressing force to the cylindrical body using the deformation action of the multilayer piezoelectric element.

Preferably, the elongate pressing member is in contact with the cylindrical body in such a manner that the axial direction intersects the axial direction of the cylindrical body.
The pressing member may have a protrusion that protrudes toward the cylindrical body.

  The laminated piezoelectric element may function as the pressing member. Alternatively, the pressing member is a separate member from the multilayer piezoelectric element, and is rotatably supported so that both ends swing in an arc shape, and one end of the pressing member is rotated by deformation of the multilayer piezoelectric element. Upon receiving the force, the other end of the pressing member may come into contact with the cylindrical body and apply a pressing force to the cylindrical body as the pressing member rotates.

  A pressing force receiving member may be further provided on the opposite side of the pressing member across the cylindrical body. In that case, the pressing force receiving member may be a pedestal that is integrally fixed to at least the casing that houses the cylindrical body, or may be configured by a second laminated piezoelectric element. Also good.

  On the opposite side of the pair of check valves from the pump chamber, a fluid suction channel and a discharge channel are provided, and the pump chamber, the suction channel, and the discharge channel are formed in a single cylindrical shape. It may be defined by the body.

  The apparatus further comprises a casing that houses the cylindrical body, and an inlet pipe and an outlet pipe that pass through the casing and connect to the cylindrical body, and the pair of check valves are disposed in the corresponding inlet pipe and outlet pipe. You may be made to do.

The check valve includes a valve seat and a valve body that selectively engages with the valve seat. One of the valve seat and the valve body includes a first magnet, and the other is a magnetic body. Or you may make it comprise from a 2nd magnet.
The valve seat may be formed in a frustoconical shape, and the valve body may be composed of a spherical member.

  According to the above-described present invention, since it has a long laminated piezoelectric element supported in a cantilever manner and the tubular body is pressed by a long pressing member, the pressing member and the pump chamber are provided. Even if the size is reduced, a large pressing force can be applied to the cylindrical body, and a sufficient discharge pressure can be obtained. Therefore, it is easy to obtain a sufficient discharge pressure even if the laminated piezoelectric element and the pump chamber are downsized, and the entire piezoelectric pump can be downsized.

  The other features of the present invention and the operational effects thereof will be described in more detail with reference to the accompanying drawings.

  Embodiments of a piezoelectric pump according to the present invention will be described below with reference to the accompanying drawings. In the drawings, the same reference numerals indicate the same or corresponding parts. The present invention also relates to, for example, a DMFC (direct methanol fuel cell) methanol supply pump, a personal computer cooling water circulation pump, a fluid supply pump or a fluid circulation pump in a medical device in a portable device such as a cellular phone. Can be applied.

  FIG. 1 is a perspective view showing an internal configuration with the top plate portion of the piezoelectric pump removed. FIG. 2 is a plan view showing the internal configuration of the piezoelectric pump. FIG. 3 is an exploded perspective view of the piezoelectric pump. 1 to 3, the piezoelectric pump 1 according to the present embodiment includes a casing 3, a cylindrical body 5, a pair of check valves 7 and 9, and a stacked layer that also functions as a pressing member. And a piezoelectric element 11. The casing 3 includes an accommodation portion 3a and a top plate portion 3b. The accommodating part 3a is comprised by the bottom face and the side surface which stands | started up from the periphery and the upper part is open | released. The top plate portion 3b is detachably provided on the housing portion 3a so as to cover the upper open portion of the housing portion 3a.

  The cylindrical body 5, the pair of check valves 7 and 9, and the laminated piezoelectric element 11 are accommodated in the accommodating portion 3 a of the casing 3. An inlet pipe 13 passes through one side surface of the accommodating portion 3a. In addition, the outlet pipe 15 penetrates the other side surface of the housing portion 3a that faces the one side surface. The ends of the inlet pipe 13 and the outlet pipe 15 on the side facing each other protrude into the accommodating portion 3a. In the present embodiment, the inlet pipe 13 and the outlet pipe 15 are formed integrally with the side surface of the casing 3, but the present invention is not limited to this, and the inlet pipe 13 and the outlet pipe 15 are separated from the casing 3. It is also possible to prepare and allow the corresponding side surfaces to penetrate.

  As shown in FIGS. 2 and 3, the cylindrical body 5 is connected to the inlet pipe 13 and the outlet pipe 15 at corresponding end portions with a pair of check valves 7 and 9 mounted therein. The The laminated piezoelectric element 11 is provided so as to extend above the cylindrical body 5 connected to the inlet tube 13 and the outlet tube 15 as described above.

  Next, details of the check valve will be described. FIG. 4 is a cross-sectional view of the cylindrical body and the pair of check valves. FIGS. 5A and 5B are a cross-sectional view and a front view of the pair of check valves, respectively. The cylindrical body 5 is a cylindrical member made of an elastic material such as silicon rubber.

  The pair of check valves 7 and 9 are inserted into the cylindrical body 5 and arranged so as to be separated from each other at a predetermined interval. A pump chamber 16 sandwiched between a pair of check valves 7 and 9 is formed inside the cylindrical body 5. Inside the cylindrical body 5, a fluid suction channel 18 and a discharge channel 20 are provided on the opposite sides of the pair of check valves 7 and 9 from the pump chamber 16. In the illustrated configuration, the pump chamber 16, the suction flow path 18, and the discharge flow path 20 are defined by a single continuous cylindrical body 5.

  The pair of check valves 7, 9 has a substantially cylindrical block 17 body, and the diameter thereof is significantly smaller than the columnar inner space of the cylindrical body 5 in the upstream portion of the shaft core portion. An orifice portion 19 is formed. A truncated conical wall portion 21 is provided on the downstream side of the orifice portion 19. The truncated conical wall portion 21 is formed in a divergent shape that has the smallest diameter at the outlet of the orifice portion 19 and increases in diameter toward the downstream. A part of the truncated cone wall portion 21 functions as a truncated cone-shaped annular valve seat. That is, the pair of check valves 7 and 9 further includes a valve body 23 formed of a spherical member, and the valve body 23 is closed by engaging with a frustoconical annular valve seat. To produce.

  One of the valve body 23 and the valve seat is composed of a first magnet (permanent magnet), and the other is a magnetic body or a second magnet (permanent magnet) that is attracted to the first magnet. It is configured. In the present embodiment, as an example, the valve body 23 is made of a magnet, and the valve seat is made of magnetic stainless steel.

  In this example, three claw portions 25 are provided at the outlet of the truncated conical wall portion 21. The three claw portions 25 are arranged so as to be spaced apart from each other at equal intervals, and are respectively supported in a cantilever manner on the outermost peripheral portion of the block body 17, and from there toward the axial core portion of the block body 17. It extends. Further, the pair of check valves 7 and 9 are configured such that a gap is generated between the tip of each claw portion 25 and the valve body 23 in the closed state where the valve body 23 is seated on the valve seat. ing.

  As an arrangement mode of the pair of check valves 7 and 9, the following modes can be considered in addition to the above. As shown by a one-dot chain line in FIG. 2, the check valves 7 and 9 can be arranged not in the cylindrical body 5 but in the corresponding inlet pipe 13 and outlet pipe 15. In such an embodiment, it is not necessary to connect the cylindrical body 5 to the inlet pipe 13 and the outlet pipe 15 while considering the positions of the pair of check valves 7 and 9, and simply connect the cylindrical body 5 to the inlet pipe 13 and the outlet pipe 15. Since it is only necessary to connect to the tube 15, the assembly process can be facilitated.

  Returning to FIGS. 1 to 3, the laminated piezoelectric element 11 has a long shape, more specifically, a plate-like form, and has a lamination direction of elements in the thickness direction of the plate. In the description of the present specification and the scope of claims, a form having a length that is at least larger than the thickness is referred to as a “long shape”. It shall include a “plate shape” whose width is considerably larger than the thickness.

  The laminated piezoelectric element 11 is disposed in the housing portion 3a of the casing 3 so that the cylindrical body 5 is located below the stacking direction at one end thereof. The laminated piezoelectric element 11 is arranged so that the axial direction of the cylindrical body 5 and the axial direction of the laminated piezoelectric element 11 intersect (particularly orthogonal in the present embodiment).

  The laminated piezoelectric element 11 is supported at the other end by the support member 27 in a cantilever manner in the accommodating portion 3a. A wiring 29 is provided at the other end of the laminated piezoelectric element 11, and the wiring 29 passes through the housing 3 a of the casing 3 and is connected to a driving power source (not shown).

  Next, the operation of the piezoelectric pump having such a configuration will be described. A driving voltage is applied to the laminated piezoelectric element 11 via the wiring 29 to deform the laminated piezoelectric element 11. Since the laminated piezoelectric element 11 is supported in a cantilever manner at the end, the above deformation appears as a downward displacement of the free end on the opposite side of the support end (see the arrow in FIG. 3). In the present embodiment, the laminated piezoelectric element 11 also functions as a pressing member, and applies a pressing force to the cylindrical body 5 using its own deformation action.

  That is, the cylindrical body 5 is crushed by the laminated piezoelectric element 11 from above, and the pressure in the pump chamber 16 is increased. When the pressure of the fluid in the pump chamber 16 increases to a certain level, in the check valve 9 provided on the downstream side of the pump chamber 16, the fluid pressure acting on the valve body 23 via the orifice portion 19 is caused by magnetic force. Overcoming the normally closed valve closing force acting on the valve body 23 and the fluid pressure acting on the valve body 23 from the discharge flow path 20 side, the valve body 23 is separated from the valve seat as shown in FIG. Then open the valve. As a result, the fluid in the pump chamber 16 flows into the discharge passage 20 through the opened check valve 9.

  On the other hand, in the check valve 7 provided on the upstream side of the pump chamber 16, when the pressure of the fluid in the pump chamber 16 increases, the pressure acts to seat the valve body 23 on the valve seat. As shown in FIG. 6B, the check valve 7 is further closed, and the fluid in the pump chamber 16 is reliably prevented from flowing back to the suction flow path 18.

  Subsequently, when the pressing end portion of the laminated piezoelectric element 11 is deformed in a direction away from the cylindrical body 5, the cylindrical body 5 tries to restore to a natural form when there is no load by its own elasticity. In the pump chamber 16, since the fluid is discharged by the amount corresponding to the collapse of the cylindrical body 5, the decompression tends to proceed as the cylindrical body 5 is restored. For this reason, in the check valve 7 provided on the upstream side of the pump chamber 16, the fluid pressure acting on the valve body 23 from the pump chamber 16 side decreases, and the valve from the suction flow path 18 side through the orifice portion 19 is reduced. The fluid pressure acting on the body 23 exceeds the normally closed valve closing force acting on the valve body 23 by the magnetic force and the fluid pressure acting on the valve body 23 from the pump chamber 16 side, as shown in FIG. In addition, the valve element 23 opens away from the valve seat.

  On the other hand, in the check valve 9 provided on the downstream side of the pump chamber 16, when the pressure of the fluid in the pump chamber 16 decreases from the state in which the fluid is discharged by the amount that the cylindrical body 5 is crushed, The check valve 7 is closed by the fluid pressure and the magnetic force from the flow path 20 side, and the fluid in the discharge flow path 20 flows to the pump chamber 16 as shown in FIG. Backflow is reliably prevented.

  Thus, by repeating the reciprocating operation in which the laminated piezoelectric element 11 crushes the cylindrical body 5 or leaves the cylindrical body 5, the fluid can be pumped in one direction in a pulsating manner without backflow. .

  By the way, as described above, the piezoelectric pump is expected to be applied to electronic devices, medical devices, and the like, and downsizing is desired. However, in an aspect in which the diaphragm defining the pump chamber is a circular thin plate, Because large displacement cannot be obtained due to the shape of the diaphragm, when trying to obtain a sufficient discharge rate, the diaphragm must be enlarged and the pump chamber must be enlarged accordingly, making it difficult to reduce the size of the pump as a whole. . This also applies to the embodiment in which the piezoelectric element for generating the displacement is in the form of a circular thin plate and the aspect in which the pressing member that presses the pump chamber is in the form of a circular thin plate. Due to the circular thin plate shape, it is difficult to generate sufficient displacement, and in the latter case, since the circular thin plate shape is supported in an annular shape on the outer periphery, large deformation of the central portion is restricted and sufficient pressing is difficult. Become.

  On the other hand, the piezoelectric pump 1 according to the present embodiment has a long laminated piezoelectric element 11 supported in a cantilever manner, and is cylindrical with the long laminated piezoelectric element 11 (pressing member). Since it is the aspect which presses the body 5, even if it reduces a pressing member and a pump chamber, a big pressing force can be provided to the cylindrical body 5, and sufficient discharge pressure can be obtained. That is, since the laminated piezoelectric element 11 is supported in a cantilever manner, a larger displacement can be obtained. In addition, since the contact target is a combination of the elongated laminated piezoelectric element 11 (pressing member) and the cylindrical body 5, it is easy to largely collapse the cylindrical body 5. For this reason, it is easy to obtain a sufficient discharge pressure even if the laminated piezoelectric element (pressing member) or the pump chamber is downsized, and the entire piezoelectric pump can be downsized. In the arrangement mode in which the axial direction of the elongated laminated piezoelectric element 11 (pressing member) and the axial direction of the cylindrical body 5 intersect (more preferably, orthogonal), the cylindrical body is more efficient. 5 can be crushed and the inside of the pump chamber 16 can be compressed, and a large discharge pressure can be obtained.

  In the present embodiment, the pump chamber 16, the suction flow path 18, and the discharge flow path 20 are defined by the continuous single cylindrical body 5, and therefore, between the suction flow path 18 and the pump chamber 16. The sealing means and the sealing means between the pump chamber 16 and the discharge flow path 20 are not required, and the configuration can be simplified and the number of parts can be reduced, whereby the piezoelectric pump 1 can be reduced in size. .

  In addition, since the pair of check valves 7 and 9 obtains a normally closed valve closing force by a magnetic force of a permanent magnet, a mechanical valve closing force such as a spring is secured while ensuring a reliable valve closing. Therefore, the configuration can be simplified and the number of parts can be reduced as compared with the aspect in which the piezoelectric pump 1 is obtained. Accordingly, the piezoelectric pump 1 can be reduced in size. Further, unlike the case where an electromagnet is used, such a magnetic force does not require a driving power supply for valve operation, and thus does not increase the power consumption of the piezoelectric pump 1 and does not generate noise. This is very advantageous in portable devices where the battery duration is a problem and medical devices where noise is a problem.

  Next, a modified embodiment relating to the pressing member of the piezoelectric pump according to the present invention will be described. In the above embodiment, the laminated piezoelectric element 11 also functions as a pressing member. However, in this embodiment, as shown in FIGS. 7 and 8, the pressing member is different from the laminated piezoelectric element 11. It is provided as a member. FIG. 7 is a perspective view showing the internal configuration of the piezoelectric pump according to the modified embodiment with the top plate portion removed, and FIG. 8 is a view taken along the arrow VIII of FIG. 7 in the vicinity of the pressing member.

  A sliding cylindrical portion 11 a is formed at the free end of the laminated piezoelectric element 11. The sliding cylindrical portion 11 a is a substantially cylindrical portion, and is formed such that the axial direction of the sliding cylindrical portion 11 a is directed to the width direction of the laminated piezoelectric element 11.

  A pressing member 131 is provided between the sliding cylindrical portion 11 a and the cylindrical body 5. The pressing member 131 is rotatably supported by the shaft support portion 135 so that both ends of the pressing member 131 swing in an arcuate locus. In the pressing member 131, an accommodating portion 137 is formed on the laminated piezoelectric element 11 side with respect to the shaft support portion 135. The accommodating portion 137 is formed in a substantially U shape on the end surface viewed from the width direction of the laminated piezoelectric element 11, and has a space in which the sliding cylindrical portion 11 a can be accommodated inside the U shape. On the other hand, a pressing piece 139 is formed on the cylindrical body 5 side with respect to the shaft support portion 135. The pressing piece 139 is a long member extending toward the cylindrical body 5, and is arranged so that the axial direction of the pressing piece intersects the axial direction of the cylindrical body 5 (particularly orthogonal in this example). Yes. Further, the length from the shaft support 135 to the tip of the pressing piece 139 is set to be larger than the length from the shaft support 135 to the tip of the housing 137.

  In such a modified piezoelectric pump according to the present embodiment, the following operations are produced in addition to the operations and operations in the above-described embodiments. When the multilayered piezoelectric element 11 is deformed, as shown in FIG. 8B, the accommodating portion 137 that is one end of the pressing member 131 receives a rotational force due to the deformation of the multilayered piezoelectric element 11, and the entire pressing member 131. Rotates. Thereby, the pressing piece 139 which is the other end of the pressing member 131 swings and comes into contact with the cylindrical body 5, and applies a pressing force to the cylindrical body 5 with the rotation of the entire pressing member 131. The body 5 is crushed. At this time, since the length from the shaft support part 135 to the tip part of the pressing piece 139 is larger than the length from the shaft support part 135 to the tip part of the housing part 137, the tip part of the pressing piece 139 is the same as that of the laminated piezoelectric element 11. It is possible to move larger than the displacement amount, and the cylindrical body 5 can be largely crushed. Therefore, it is easy to obtain a sufficient discharge pressure even if the laminated piezoelectric element and the pump chamber are downsized, and the entire piezoelectric pump can be downsized. Further, the increase in displacement by the pressing member 131 is not because the laminated piezoelectric element 11 is formed in a thin circular plate shape and is supported in an annular shape, but is formed in a long shape and supported in a cantilever manner. It is possible only from.

  Next, a modified embodiment relating to the pressing mode of the piezoelectric pump according to the present invention will be described. FIG. 9 is an exploded perspective view of the piezoelectric pump according to this modified embodiment. FIG. 10 is a cross-sectional view in the vicinity of the cylindrical body in the assembled state, showing a vertical cross section in a direction in which the axis of the cylindrical body is a perpendicular line. As understood from FIGS. 9 and 10, in the assembled state, a receiving table 141 as a pressing force receiving member is provided on the opposite side of the laminated piezoelectric element (pressing member) 11 with the cylindrical body 5 interposed therebetween. Yes.

  The cradle 141 is a substantially rectangular parallelepiped member, and has a concave surface 141 a on the upper surface thereof, that is, the surface in contact with the cylindrical body 5. In addition, the cradle 141 is erected on the bottom surface of the housing portion 3a of the casing 3, and in short, when a pressing force is applied to the tubular body 5, it abuts on and supports the tubular body 5. It is provided to do.

  In such a modified piezoelectric pump according to the present embodiment, the receiving base 141 abuts and supports the cylindrical body 5 and can receive the pressing force applied to the cylindrical body 5. The body 5 is crushed efficiently. Therefore, it is easy to obtain a sufficient discharge pressure even if the laminated piezoelectric element and the pump chamber are downsized, and the downsizing of the entire piezoelectric pump 1 can be further promoted.

  The cradle described above is not limited to an aspect prepared separately from the casing 3, and may be implemented, for example, in an aspect in which the bottom surface of the housing portion 3 a of the casing 3 is raised upward. . That is, the cradle only needs to be fixed in relation to the casing 3.

  Next, a further modified embodiment of the pressing mode of the piezoelectric pump according to the present invention will be described. (A) of FIG. 11 is a figure of the same aspect as FIG. 10 regarding this Embodiment, (b) of FIG. 11 is a perspective view of the pressing force receiving member regarding this Embodiment. In the present embodiment, as shown in FIG. 11, a second laminated piezoelectric element 143 and a cradle 145 are provided as pressing force receiving members.

  The second multilayer piezoelectric element 143 is provided on the opposite side of the first multilayer piezoelectric element 11 with the cylindrical body 5 interposed therebetween, and operates in the same manner as the multilayer piezoelectric element 11. The aspect is provided so as to be symmetrical with the laminated piezoelectric element 11 with the cylindrical body 5 interposed therebetween. That is, when the tip of the multilayer piezoelectric element 11 is deformed downward and the cylindrical body 5 is crushed, the tip of the second multilayer piezoelectric element 143 is deformed upward to try to collapse the cylindrical body 5. The operation is performed.

  Further, it can be said that the cradle 145 is the same as the cradle 141 described above except that the cradle 145 is composed of a pair of parts separated at a position corresponding to the lower part of the laminated piezoelectric element 11. That is, the cradle 145 has a concave surface 141 a on its upper surface and a space 147 at a position corresponding to a lower portion of the laminated piezoelectric element 11. In this space 147, the second laminated piezoelectric element 143 extends in a deformable manner.

Also in the piezoelectric pump according to this modified embodiment, the second laminated piezoelectric element 143 and the cradle 145 are in contact with the cylindrical body 5 and receive a pressing force applied to the cylindrical body 5. Therefore, the cylindrical body 5 is efficiently crushed. Therefore, it is easy to obtain a sufficient discharge pressure even if the laminated piezoelectric element and the pump chamber are downsized, and the downsizing of the entire piezoelectric pump 1 can be further promoted.
In addition, regarding this Embodiment, it is also possible to abbreviate | omit the receiving stand 145.

  Further, modified embodiments of the pressing mode of the piezoelectric pump according to the present invention will be described. FIG. 12 is a diagram of the same mode as that of FIG. 10 and FIG. In the present embodiment, as shown in FIG. 11, the second laminated piezoelectric element 143 is provided as a pressing force receiving member, and the pressing member (the laminated piezoelectric element 11 in the present embodiment) and the pressing force receiver. Both members (second laminated piezoelectric element 143 in this embodiment) have protrusions 149a and 149b.

  The protrusions 149 a and 149 b are provided at the tip portions of the corresponding plate-like multilayer piezoelectric element 11 and second multilayer piezoelectric element 143, respectively, and protrude in a direction approaching the cylindrical body 5.

  Even in such a modified piezoelectric pump according to the present embodiment, the second laminated piezoelectric element 143 can contact the cylindrical body 5 and receive the pressing force applied to the cylindrical body 5. The cylindrical body 5 is crushed efficiently. In addition, since the pressing force and the reaction force are transmitted to the cylindrical body 5 through the tops of the protrusions 149a and 149b, the cylindrical body 5 can be largely crushed with higher pressure. Therefore, it is easy to obtain a sufficient discharge pressure even if the laminated piezoelectric element and the pump chamber are downsized, and the downsizing of the entire piezoelectric pump 1 can be further promoted.

  In addition, regarding this Embodiment, it is also possible to provide a protrusion on only one of the pressing member and the pressing force receiving member.

  Further, the above-described plurality of embodiments are not limited to being implemented by themselves, and can be implemented by combining features of several embodiments. For example, in the modified embodiment of FIGS. 11 and 12, as shown in FIGS. 7 and 8, the pressing member and the pressing force receiving member are provided separately from the corresponding laminated piezoelectric elements 11 and 143, and the pressing member provided separately. The cylindrical body may be largely crushed by moving the end portion of the member or the pressing force receiving member largely beyond the displacement amount of the laminated piezoelectric element. Incidentally, in that case, the protrusion is provided at the end of the pressing member or the pressing force receiving member.

  Next, a modified embodiment relating to a check valve of the piezoelectric pump according to the present invention will be described. FIG. 13 is a diagram showing a configuration of a check valve used in the present embodiment, where (a) shows a valve open state and (b) shows a valve closed state. The pair of check valves 207 and 209 used in the present embodiment is composed only of an elastic body such as rubber. The check valves 207 and 209 have a generally cylindrical shape, and the outer diameter decreases from the upstream side toward the downstream side. In addition, a space serving as a fluid flow path is formed inside the check valves 207 and 209, and this space also decreases in diameter from the upstream side toward the downstream side. Of the fluid flow paths inside the check valves 207 and 209, the diameter of the most downstream end is almost the same in order to secure the wall thickness and ensure the stability of the small diameter tip of the check valves 207 and 209. Has no straight part.

  In such a modified piezoelectric pump according to the present embodiment, as in the above-described embodiment, the pressing member repeatedly reciprocates so as to crush the cylindrical body 5 or to move away from the cylindrical body 5. The fluid can be pumped in one direction in a pulsating manner without backflow.

  In addition, in the check valves 207 and 209, due to the action of the tapered shape and the arrangement direction, in the flow from the upstream side to the downstream side, its own pressure functions as a valve opening force, and from the downstream side to the upstream side. In the flow, its own pressure functions as a valve closing force. Therefore, the valve can be secured by using the pressure of the flow itself, and the configuration can be simplified and the number of parts can be reduced as compared with a mode in which a mechanical valve closing force such as a spring is obtained. 1 can be miniaturized.

  Although the contents of the present invention have been specifically described with reference to the preferred embodiments, various modifications can be made by those skilled in the art based on the basic technical idea and teachings of the present invention. It is self-explanatory.

It is a perspective view which removes a top plate part and shows an internal structure of the piezoelectric pump which concerns on embodiment of this invention. It is a top view which shows the internal structure of a piezoelectric pump. It is a disassembled perspective view of a piezoelectric pump. It is sectional drawing of the cylindrical body and a pair of check valve of the piezoelectric pump which concerns on this Embodiment. (A) And (b) is a sectional view and a front view of a pair of check valves, respectively. It is a figure which shows the structure of the non-return valve used for this Embodiment, (a) is a valve opening state, (b) is a figure which shows a valve closing state. It is a perspective view which removes a top plate part and shows an internal structure of the piezoelectric pump which concerns on the modified embodiment of this invention. It is the figure which looked along the arrow VIII of FIG. 7 regarding the press member vicinity. It is an exploded perspective view of a piezoelectric pump according to a modified embodiment having a cradle. FIG. 10 is a cross section in the vicinity of the cylindrical body in an assembled state, showing a vertical cross section in a direction in which the axis of the cylindrical body is a perpendicular line. (A) is a figure of the same aspect as FIG. 10 regarding this Embodiment, (b) is a perspective view of the receiving stand regarding this Embodiment. It is a figure of the same aspect as Fig.10 and Fig.11 (a) of modified embodiment which has a 2nd laminated piezoelectric element. It is a figure which shows the structure of the non-return valve used for the modified embodiment, (a) is a valve opening state, (b) is a figure which shows a valve closing state.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Piezoelectric pump 5 Cylindrical body 7, 9 Check valve 11 Laminated piezoelectric element (pressing member)
16 Pump chamber 18 Suction flow path 20 Discharge flow path 21 Frozen conical wall (valve seat)
23 Valve body 131 Pressing member 141, 145 Receptacle (pressing force receiving member)
143 Second laminated piezoelectric element (pressing force receiving member)
149a, 149b Protrusion 207, 209 Check valve

Claims (12)

A cylindrical body in which a pump chamber is formed;
A pair of check valves located on both sides of the pump chamber;
An elongated laminated piezoelectric element supported in a cantilever manner;
A piezoelectric pump comprising a long pressing member that applies a pressing force to the cylindrical body by using a deformation action of the laminated piezoelectric element.   2. The piezoelectric pump according to claim 1, wherein the elongate pressing member is in contact with the cylindrical body such that an axial direction of the elongated pressing member intersects an axial direction of the cylindrical body.   The piezoelectric pump according to claim 1, wherein the pressing member has a protrusion that protrudes toward the cylindrical body.   The piezoelectric pump according to any one of claims 1 to 3, wherein the laminated piezoelectric element functions also as the pressing member. The pressing member is a separate member from the laminated piezoelectric element, and is rotatably supported so that both ends swing in an arc shape,
One end of the pressing member receives a rotational force due to deformation of the laminated piezoelectric element, and the other end of the pressing member abuts on the cylindrical body and applies a pressing force to the cylindrical body as the pressing member rotates. The piezoelectric pump as described in any one of Claims 1 thru | or 3 to provide.   The piezoelectric pump according to any one of claims 1 to 5, further comprising a pressing force receiving member on a side opposite to the pressing member sandwiching the cylindrical body.   The piezoelectric pump according to claim 6, wherein the pressing force receiving member is a receiving base that is integrally fixed to at least a casing that houses the cylindrical body.   The piezoelectric pump according to claim 6, wherein the pressing force receiving member includes a second laminated piezoelectric element. On each side of the pair of check valves opposite to the pump chamber, a fluid suction channel and a discharge channel are provided,
The piezoelectric pump according to any one of claims 1 to 8, wherein the pump chamber, the suction channel, and the discharge channel are defined by a single cylindrical body. A casing that accommodates the cylindrical body, and an inlet pipe and an outlet pipe that penetrate the casing and connect to the cylindrical body;
The piezoelectric pump according to any one of claims 1 to 9, wherein the pair of check valves are disposed in the corresponding inlet pipe and outlet pipe. The check valve includes a valve seat and a valve body that selectively engages the valve seat,
11. The piezoelectric pump according to claim 1, wherein one of the valve seat and the valve body is configured by a first magnet, and the other is configured by a magnetic body or a second magnet.   The piezoelectric pump according to claim 11, wherein the valve seat is formed in a truncated cone shape, and the valve body is formed of a spherical member.

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