JP2010196470A - Driver-integrated piezoelectric pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat dissipation structure of a driver-integrated piezoelectric pump successfully dissipating heat generated by a heating element of a drive substrate, in the driver-integrated piezoelectric pump having received in a single housing a piezoelectric vibrator with a liquid pump chamber formed in either of the front and rear surfaces of the piezoelectric vibrator and an atmosphere chamber formed in the other surface, and a control substrate having mounted on it an electric component for controlling supply of electricity to the piezoelectric vibrator, wherein the piezoelectric vibrator is vibrated to perform supply and discharge of liquid into and from the liquid pump chamber, thereby performing a pumping action. <P>SOLUTION: In this driver-integrated piezoelectric pump, the housing is formed with a substrate receiving space for receiving the control substrate, an atmosphere chamber path for connecting the substrate receiving space to the atmosphere chamber, and an outside communication path for connecting the substrate receiving space to the outside of the housing. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a piezoelectric pump having a piezoelectric pump and its control board built in the same housing.

  A piezoelectric pump forms a variable volume chamber (liquid pump chamber) between a plate-like piezoelectric vibrator and a housing, and vibrates the piezoelectric vibrator to change the volume of the variable volume chamber to obtain a pump action. Yes. More specifically, a pair of flow valves connected to the variable volume chamber have a pair of check valves having different flow directions (a check valve that allows fluid flow to the variable volume chamber and a reverse valve that allows fluid flow from the variable volume chamber). When the volume of the variable volume chamber is changed by the vibration of the piezoelectric vibrator, the operation of closing one of the pair of check valves and opening the other is repeated accordingly, so that a pump action is obtained.

The present applicant is developing a piezoelectric pump that is used as a cooling water circulation pump of a water-cooled notebook personal computer by taking advantage of the feature of the piezoelectric pump that can be made thin.
Special table 2004-517240 gazette JP 2004-60640 A

  In order to reduce the size, it is advantageous to store the piezoelectric vibrator and a driving substrate (driver) for applying a driving voltage to the piezoelectric vibrator in the same housing. However, there are heating elements such as IC, inductor, and FET circuit on the driving substrate. For this reason, the temperature in the housing rises due to self-heating of these elements, and may reach the junction temperature.

  In addition, since the piezoelectric vibrator is driven at a high voltage and the drive substrate generates a high voltage, the drive substrate is installed outside the housing in order for the piezoelectric pump integrated with the drive substrate to satisfy the UL standard. In this case, a container (housing) that isolates the drive substrate from the outside by a certain distance is required, and it is impossible to reduce the size. Therefore, in order to achieve downsizing and satisfy the UL standard, the drive board must be installed in the housing, and in order to achieve downsizing, measures against heat of the drive board are indispensable.

  The present invention is based on the above problem awareness, and when the piezoelectric vibrator and the drive board are housed in the same housing, the heat dissipation structure of the driver built-in piezoelectric pump that can efficiently dissipate the heat generated by the heating elements of the drive board. The purpose is to obtain.

  In the piezoelectric pump according to the present invention, an air chamber (atmosphere pump chamber) is inevitably formed on the surface of the piezoelectric vibrator opposite to the liquid pump chamber. Focusing on the fact that the movement of air) has occurred, the focus was on whether this movement of the atmosphere could be used for heat dissipation.

  The present invention provides a piezoelectric vibrator in which a liquid pump chamber is formed on one surface of the front and back surfaces and an air chamber is formed on the other surface in a single housing, and a control board on which electric components for power supply control for the piezoelectric vibrator are mounted. In the piezoelectric pump with a built-in driver that pumps the liquid by supplying and discharging liquid into the liquid pump chamber by vibrating the piezoelectric vibrator, a housing space for housing the control board in the housing, and the board housing An atmosphere chamber passage that communicates the space with the atmosphere chamber and an external communication passage that communicates the substrate storage space with the outside of the housing are formed.

  Specifically, the housing includes a main housing having a circular recess for accommodating the piezoelectric vibrator and a control board storage recess on the front and back, an upper lid for closing the circular recess of the main housing, and a lower cover for closing the control board storage recess. It is practical that the air chamber passage and the external communication passage are formed in the main housing.

  Further, it is preferable that the control substrate is disposed on the surface of the pump chamber opposite to the piezoelectric vibrator via a wall surface of the pump chamber at a position where at least a portion overlaps the pump chamber in plan view.

  A part of the atmosphere chamber passage can be formed by a power supply line housing groove through which a power supply line for the piezoelectric vibrator passes.

  On the control board (circuit board), at least an IC as a heat generating element, an inductor, and an FET circuit are mounted.

  According to the present invention, a substrate housing space for housing a control board, an atmosphere chamber passage for communicating the substrate housing space with the atmosphere chamber, and a substrate housing space for communication with the outside of the housing in a single housing constituting the piezoelectric pump. Since the external communication passage is formed, the movement of the atmosphere (air) inevitably generated on the atmosphere chamber side due to the pump action can be exerted on the atmosphere chamber passage, the substrate storage space and the external communication passage. By moving, it is possible to efficiently dissipate heat and to eliminate the possibility that the electric elements on the driving substrate reach the junction temperature.

  1 to 5 show an embodiment of a piezoelectric pump 100 according to the present invention. The piezoelectric pump 100 includes a piezoelectric vibrator 10, a housing 20, and a drive substrate 50. The housing 20 includes an upper lid (upper housing) 20A, a main housing 20B, and a lower lid (lower housing) 20C. The main housing 20B is opened to the upper lid 20A side and has a circular recess 41 (see FIGS. 3 and 5). ) And a substrate storage recess (substrate storage space) 51 (see FIGS. 4 and 5) is formed to open to the lower lid 20C side. On the periphery of the circular recess 41, an O-ring housing annular groove 41a is formed concentrically.

  As shown in FIGS. 3 and 5, the piezoelectric vibrator 10 includes a circular metal shim 11 and a circular piezoelectric body 12 formed on one of the front and back surfaces of the shim 11. In this embodiment, the shim 11 faces the liquid pump chamber P side, and the piezoelectric body 12 faces the atmosphere chamber A side.

The shim 11 is a conductive metal thin plate made of stainless steel having a thickness of about 30 to 300 μm or 42 alloy, and the piezoelectric body 12 is made of PZT (Pb (Zr, Ti) O ₃ ) having a thickness of about 50 to 300 μm, for example. It is comprised from the piezoelectric material of this, and the polarization process is given to the front and back direction. Such a piezoelectric vibrator is well known. When an alternating electric field is applied to the front and back of the piezoelectric body 12, a cycle in which one of the front and back of the piezoelectric body 12 extends and the other contracts is repeated, and the shim 11 (piezoelectric vibrator 10) vibrates.

  As shown in FIG. 5, a first power supply line (lead member) 14 is conductively connected to the piezoelectric vibrator 10 through a conductive rubber 18 at the surface periphery of the piezoelectric body 12. The conductive rubber 18 is made of conductive rubber that maintains its rubber property and has a small volume resistivity value. In addition, the second power supply line 15 is connected to the wiring connection protrusion 11 c that is integrally formed by protruding from the shim 11 in the radial direction.

  An O-ring 27 is inserted into the O-ring housing annular groove 41a of the main housing 20B, and the piezoelectric vibrator 10 is inserted into the circular recess 41. The piezoelectric vibrator 10 is tightly supported in a liquid-tight manner by placing the upper cover 20A on the main housing 20B with the annular guide 28 interposed on the periphery of the piezoelectric vibrator 10. A liquid pump chamber P is formed between the piezoelectric vibrator 10 and the circular recess 41, and an air chamber (atmosphere pump chamber) A is formed between the piezoelectric vibrator 10 and the upper lid 20A.

  In the main housing 20B, a suction-side liquid reservoir chamber 42 and a discharge-side liquid reservoir chamber 43 are formed in the circular concave portion 41 so as to be located at an eccentric symmetry position with respect to the plane center of the piezoelectric vibrator 10 (circular concave portion 41). Yes. Between the suction-side liquid reservoir chamber 42 and the liquid pump chamber P, and between the discharge-side liquid reservoir chamber 43 and the liquid pump chamber P, a suction-side check valve 32 and a discharge-side check valve 33 are provided, respectively. The main housing 20B is formed with a suction port 24 and a discharge port 25 communicating with the suction-side liquid storage chamber 42 and the discharge-side liquid storage chamber 43.

  The suction-side check valve 32 is a suction-side check valve that allows a fluid flow from the suction port 24 to the liquid pump chamber P and does not allow the reverse fluid flow. The discharge-side check valve 33 is a liquid pump chamber. This is a discharge-side check valve that allows fluid flow from P to the discharge port 25 but not vice versa.

  The check valves 32 and 33 have the same configuration, and are provided with umbrellas 32b and 33b made of an elastic material on perforated substrates 32a and 33a that are bonded and fixed to the flow path.

  In the main housing 20B, feed line storage grooves 45 and 46 are formed in the cylindrical portion 44 around the circular recess 41 so as to have different circumferential positions (FIGS. 4 and 5). The power supply line storage grooves 45 and 46 pass the first power supply line 14 and the second power supply line 15, and have a large cross-sectional area so that a sufficient air circulation space can be ensured even in the passed state.

  As shown in FIGS. 6, 4, and 5, on the drive substrate 50, there are electrical parts 53 that perform power feeding control on the piezoelectric vibrator 10 and printed wiring (not shown) that connects the electrical parts 53. Is formed. The power supply control electrical component 53 includes an IC 53a (see FIG. 6), an inductor 53b (same), and an FET circuit 53c (same) as heating elements. The first power supply line 14 and the second power supply line 15 guided to the outside of the atmospheric chamber A (circular recess 41) through the power supply line storage grooves 45 and 46 are connected to the drive substrate 50.

  The main housing 20B is formed with an important lack (atmosphere chamber passage, through hole) 52 that allows the atmosphere chamber A and the substrate housing recess 51 to communicate with each other via the power supply line housing grooves 45 and 46 (FIGS. 4 and 4). 5). As shown in FIG. 4, the upper surface of the important piece 52 is closed by the upper lid 20A that covers the main housing 20B.

  The main housing 20B also has an external communication path (hole) 54 that allows the substrate storage recess 51 to communicate with the outside. Accordingly, the substrate housing recess 51 communicates with the atmosphere chamber A via the important part 52 and the power supply line housing grooves 45 and 46 and communicates with the outside via the external communication path 54. For this reason, the atmosphere chamber A communicates with the outside even when the drive substrate 50 is fitted in the substrate housing recess 51 of the main housing 20B and covered with the lower lid 20C. That is, when the piezoelectric vibrator 10 vibrates and the volume of the atmospheric chamber A is reduced, an outward air flow is generated through the power supply line storage grooves 45 and 46, the important part 52, the substrate storage recess 51 and the external communication path 54. On the contrary, when the volume of the atmospheric chamber A increases, an inward air flow is generated through the external communication path 54, the substrate housing recess 51, the important part 52, and the power supply line housing grooves 45 and 46.

  In the piezoelectric pump 100 of the present embodiment, when the piezoelectric vibrator 10 is elastically deformed (vibrated) in the forward and reverse directions, the suction side check valve 32 is opened and the discharge side check valve is opened in a stroke in which the volume of the liquid pump chamber P is expanded. Since 33 is closed, the liquid flows into the liquid pump chamber P from the suction port 24. On the other hand, in the process of reducing the volume of the liquid pump chamber P, the discharge check valve 33 is opened and the suction check valve 32 is closed, so that the liquid flows out from the liquid pump chamber P to the discharge port 25. Accordingly, the pump action can be obtained by elastically deforming (vibrating) the piezoelectric vibrator 10 continuously in the forward and reverse directions.

  During this pumping action, the volume of the atmospheric chamber A expands and contracts at the same time. When the volume of the atmospheric chamber A is reduced, an outward air flow is generated through the power supply line storage grooves 45 and 46, the important portion 52, the substrate storage recess 51, and the external communication path 54. When heat generated by the electrical component 53 on the substrate 50 is released and the volume of the atmosphere chamber A is increased, conversely, the inward direction passing through the external communication path 54, the substrate storage recess 51, the important notch 52, and the power supply line storage grooves 45, 46. Therefore, heat generated by the electric component 53 on the drive substrate 50 can be released by this air flow.

  Further, as can be seen from FIG. 5, the drive substrate 50 is disposed on the lower surface of the liquid pump chamber P opposite to the piezoelectric vibrator 10 via the lower wall surface of the liquid pump chamber P, at least a part of which is liquid. It is arranged at a position overlapping with the pump chamber P in plan view. With such a structure, the cooling liquid flowing into and out of the liquid pump chamber P efficiently removes heat generated from the control board disposed in the housing via the lower wall surface of the liquid pump chamber P. Is possible.

  In the above embodiment, the power supply line storage grooves 45 and 46 are used as part of the atmospheric chamber flow path that allows the atmospheric chamber A and the substrate storage recess 51 to communicate with each other. However, an independent atmospheric chamber flow path may be provided. . The position and size of the external communication path 54 also have a degree of freedom.

It is a top view which shows one Embodiment of the piezoelectric pump by this invention. It is the same rear view. It is sectional drawing which follows the III-III line | wire of FIG. 1, FIG. It is sectional drawing which follows the IV-IV line of FIG. 1, FIG. It is a disassembled perspective view of the same piezoelectric pump. It is a top view of a drive substrate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Piezoelectric pump 10 Piezoelectric vibrator | oscillator 11 Shim 11c Wiring connection protrusion 12 Piezoelectric body 14 1st electric power feeding line 15 2nd electric power feeding line 18 Conductive rubber 20 Housing 20A Upper lid 20B Main housing 20C Lower lid 24 Intake port 25 Discharge port 27 O-ring 29 Annular electrode terminal 30 Suction passage 31 Discharge passage 32, 33 Check valve 41 Circular recess 41a O-ring accommodation annular groove 45 46 Feed line accommodation groove (atmosphere chamber passage)
50 Drive substrate 51 Substrate storage recess (substrate storage space)
52 Important Missing (Atmosphere Chamber Passage)
53 Electrical component 54 External communication path A Air chamber P Liquid pump chamber

Claims (5)

In a single housing, a piezoelectric vibrator in which a liquid pump chamber is formed on one surface of the front and back and an air chamber is formed on the other surface, and a control board on which power supply control electrical components for the piezoelectric vibrator are mounted, A piezoelectric pump with a built-in driver that performs pumping by supplying and discharging liquid into the liquid pump chamber by vibrating the piezoelectric vibrator,
Formed in the housing are a substrate storage space for storing the control substrate, an atmosphere chamber passage for communicating the substrate storage space with the atmosphere chamber, and an external communication passage for communicating the substrate storage space with the outside of the housing. A piezoelectric pump with a built-in driver. 2. The piezoelectric pump with a built-in driver according to claim 1, wherein the housing includes a main housing having a circular recess for storing a piezoelectric vibrator and a control substrate storage recess on the front and back, and an upper lid for closing the circular recess of the main housing; A piezoelectric pump with a built-in driver, which includes a lower lid that closes a control board housing recess, and in which the atmosphere chamber passage and the external communication passage are formed in a main housing. 3. The driver built-in pump according to claim 1, wherein the control board is disposed on a surface of the pump chamber opposite to the piezoelectric vibrator via a wall surface of the pump chamber at a position at least partially overlapping the pump chamber in plan view. The driver built-in piezoelectric pump. The piezoelectric pump with a built-in driver according to any one of claims 1 to 3, wherein a part of the atmosphere chamber passage is formed by a power supply line housing groove through which a power supply line to the piezoelectric vibrator is passed. 5. The driver built-in piezoelectric pump according to claim 1, wherein at least an IC, an inductor, and an FET circuit as heating elements are mounted on a control board.