JP2010249065A - Piezoelectric pump with built-in driver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric pump with a built-in driver capable of preventing a housing from being deformed owing to pressure in a liquid pump chamber if a portion of liquid pump chamber formed by the piezoelectric oscillator and a control substrate of a piezoelectric oscillator are accommodated in the same housing by overlapping them when viewed from the above. <P>SOLUTION: In the piezoelectric pump with a built-in driver, a reinforcing support is formed which is partially situated in a portion where the liquid pump chamber and a substrate receiving groove are overlapped, within the substrate receiving groove of the housing. The reinforcing support connects counter wall surfaces of the substrate receiving groove. The control substrate has a relief part which is formed to keep off the reinforcing support. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a piezoelectric pump with a built-in driver in which a piezoelectric pump and its control board are built in the same housing.

  A piezoelectric pump forms a liquid pump chamber (variable volume chamber) between a disk-shaped piezoelectric vibrator and a housing, and vibrates the piezoelectric vibrator to change the volume of the liquid pump chamber to obtain a pump action. ing. More specifically, a pair of flow valves connected to the liquid pump chamber are provided with a pair of check valves having different flow directions (a check valve that allows fluid flow to the liquid pump chamber and a reverse flow that allows fluid flow from the liquid pump chamber). When the volume of the liquid pump 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.

  The present applicant is developing a piezoelectric pump used as a cooling water circulation pump of, for example, a water-cooled notebook personal computer, taking advantage of the feature of the piezoelectric pump that can be made small and thin.

Japanese Unexamined Patent Publication No. 4-175479 JP 2004-060640 A Special Table 2004-517240 JP 2008-180091 A International Publication No. 2009-001757

  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. The applicant has also proposed a piezoelectric pump with a built-in driver in which a part of the liquid pump chamber and the drive substrate are arranged so as to overlap (overlap) in plan view in order to further reduce the size (see FIG. (Japanese Patent Application Nos. 2008-183144 and 2009-13847).

  However, in the piezoelectric pump with a built-in driver that overlaps a part of the liquid pump chamber and the driving substrate in plan view, the bottom wall on the driving substrate side of the liquid pump chamber has a cantilever structure, and the size is reduced. It is pointed out that the cantilever structure becomes thinner as the process proceeds, so that permanent distortion may occur due to forward and reverse liquid pressures periodically applied to the pump chamber. If the cantilever part of the bottom wall of the liquid pump chamber is deformed, the compressibility of the O-ring that seals the flat circular pump chamber will change depending on the location, which may be caused by liquid leakage due to insufficient compressibility or aging due to increased compression set. Liquid leakage may occur. In addition, distortion may be applied to the planar circular piezoelectric vibrator, and the displacement and rigidity of the piezoelectric vibrator may be affected, thereby reducing the pump flow rate and the closing pressure.

  In the present invention, based on the awareness of the above problems, the piezoelectric vibrator and the drive substrate are accommodated in the same housing, and a part of the liquid pump chamber and the drive substrate are overlapped (superposed) when viewed in plan. It is an object of the present invention to obtain a driver built-in piezoelectric pump that can effectively prevent deformation of the pump chamber on the side of the drive substrate.

  According to the present invention, a piezoelectric vibrator that forms a liquid pump chamber on at least one side of the front and back and a control board on which electric parts for power supply control for the piezoelectric vibrator are mounted in a single housing, and the piezoelectric vibration In the piezoelectric pump with a built-in driver for supplying and discharging liquid to and from the liquid pump chamber by vibrating the child to perform a pumping action, a part of the housing is superposed on the housing as viewed in plan in the liquid pump chamber. A substrate storage groove for storing the substrate storage groove is formed, and a reinforcing column is formed in the substrate storage groove so as to be partially positioned at the overlapping portion and connecting the opposing wall surfaces of the substrate storage groove. It is characterized by the formation of a relief that avoids the column.

  It is practical to form the reinforcing column and the relief portion of the control board in the radial direction of the liquid pump chamber. Further, when this radial direction is made coincident with the insertion direction of the control board into the board housing groove, the assemblability can be improved.

  The housing includes, for example, a main housing having a substrate storage space including a circular recess for storing the piezoelectric vibrator and a substrate storage groove, and an upper housing for closing the circular recess of the main housing and an open portion of the substrate storage space. Can do.

  According to the present invention, in the piezoelectric pump with a built-in driver in which a housing accommodating groove for accommodating a control substrate is formed by overlapping a part of the housing in plan view in the liquid pump chamber, the liquid pump is provided in the substrate accommodating groove. Since the reinforcing column for connecting the opposing wall surface of the substrate storage groove is formed partially at the overlapping portion of the chamber and the substrate storage groove, and the escape portion for avoiding the reinforcement column is formed on the control board, the driver While reducing the size and thickness of the built-in piezoelectric pump, it is possible to prevent deformation of the wall surface on the substrate storage groove side of the liquid pump chamber and enhance durability.

It is a disassembled perspective view which shows one Embodiment of the piezoelectric pump with a built-in driver of this invention. It is sectional drawing which follows the II-II line in the assembly state of the piezoelectric pump of FIG. It is sectional drawing which follows the III-III line. It is sectional drawing which follows the IV-IV line of FIG. It is sectional drawing which follows the VV line of FIG. It is sectional drawing corresponding to FIG. 2 which shows another embodiment of the piezoelectric pump with a built-in driver of this invention.

  1 to 5 show an embodiment of a piezoelectric pump with a built-in driver according to the present invention. The piezoelectric pump 20 has a main housing (lower housing) 21 and an upper housing 22 made of a molded product of a synthetic resin material (for example, PBT (polybutylene terephthalate) resin, PPS (polyphenylene sulfide) resin).

  Between the main housing 21 and the upper housing 22, the piezoelectric vibrator 10 is tightly supported in a liquid-tight manner via an O-ring 27 and an annular clamping member (guide) 28. A liquid pump chamber P is formed between the 21 circular recesses 26. An atmospheric chamber A is formed between the piezoelectric vibrator 10 and the upper housing 22. The atmosphere chamber A may be opened or sealed.

  The main housing 21 has a cooling water (liquid) suction port 24 and a discharge port 25 opened. The suction port 24 and the discharge port 25 have a suction flow path 30 and a discharge flow opening to the liquid pump chamber P side. It communicates with the road 31. A check valve unit 23 is fixed to the main housing 21 across the suction passage 30 and the discharge passage 31. The check valve unit 23 includes a suction-side check valve (umbrella) 32 that allows a fluid flow from the suction port 24 to the liquid pump chamber P and does not allow the reverse fluid flow, and a discharge port 25 from the liquid pump chamber P. A discharge-side check valve (umbrella) 33 is provided that allows fluid flow to and not vice versa. The check valves 32 and 33 in the illustrated embodiment have the same configuration, and the flow path holes 32b and 33b are normally closed by umbrellas 32a and 33a made of an elastic material.

  In the above-described piezoelectric pump 20, 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 33 is opened in the process of expanding the volume of the liquid pump chamber P. In order to close, the liquid flows into the liquid pump chamber P from the suction port 24. On the other hand, in the stroke in which the volume of the liquid pump chamber P decreases, the discharge side check valve 33 opens and the suction side check valve 32 closes, 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.

  In the present embodiment, in the piezoelectric pump having the basic structure described above, the main housing 21 is provided with a suction port 24 and a discharge port 25 in order to house a control board (drive control board) 40 that drives and controls the piezoelectric vibrator 10. A substrate storage space 21a is formed in which the end surface opposite to the opening end surface is the substrate insertion opening 21b. A part of the upper surface of the substrate storage space 21a is opened by the upper surface opening part 21c, and overlaps with a part of the circular concave part 26 below the circular concave part 26 (piezoelectric vibrator 10) when seen in a plan view. A substrate storage groove 21d is formed (the plane position is coincident). That is, the substrate housing groove 21d has a bottom wall 21e and an upper wall 21f (FIGS. 2 and 4) for receiving the control substrate 40 inserted from the substrate insertion opening 21b side. 10 extends toward the center. The upper wall 21 f is an inner wall in which the concave portion 26 of the pump chamber P exists in an upper part thereof, whereas the bottom wall 21 e is an outer wall of the housing 21. On the bottom wall 21e, there are formed a convex portion 21e2 with which the bottom surface of the control board 40 in the drawing contacts and an air circulation space 21e1.

  Reinforcing columns 21X are formed in the main housing 21 so as to be positioned at a portion where the circular recess 26 (liquid pump chamber P) and the substrate storage groove 21d overlap. This reinforcing column 21X connects the upper wall 21f and the bottom wall 21e of the substrate storage groove 21d that face each other, and extends radially outward from the center of the circular recess 26 and in the extending direction of the substrate storage groove 21d. It is formed towards. This reinforcing column 21X prevents the upper wall 21f (the wall surface on the substrate storage groove 21d side of the liquid pump chamber P) from being deformed to the bottom wall 21e side.

  The control substrate 40 is inserted into the substrate storage space 21a (substrate storage groove 21d), has a planar rectangular shape when viewed macroscopically, and reinforces the main housing 21 at a substantially central portion of the distal end portion in the insertion direction. An escape portion (notch) 45 that avoids the column 21X is formed. In addition, a pair of inclined walls 21g that are inclined with respect to a direction orthogonal to the plate thickness plane of the control substrate 40 are formed in the inner portions of the substrate housing grooves 21d divided by the reinforcing support columns 21X. The inclined wall 21g narrows the height of the substrate housing groove 21d toward the back, and the upper edge in the insertion direction of the control board 40 abuts linearly on the intermediate portion in the height direction (see FIG. 2). In FIG. 5, the pair of inclined walls 21g are symbolically indicated by triangles.

  As shown in FIGS. 1 and 2, an electrical component (electronic circuit component) 41 that controls power feeding to the piezoelectric vibrator 10 and a printed wiring that connects the electrical components 41 are formed on the control board 40. Yes. The power supply control electrical component 41 includes an IC, an inductor, and an FET circuit as heating elements protruding on the substrate, and the printed wiring includes power supply terminals 42 and 43 to the piezoelectric vibrator 10. It is.

  The configuration around the piezoelectric vibrator 10 of the present embodiment will be described as follows. The piezoelectric vibrator 10 is a unimorph type having a planar circular shim 11 and a circular piezoelectric body (piezoelectric layer) 12 formed on one of the front and back surfaces of the shim 11. The piezoelectric body 12 is located on the liquid pump chamber P side.

The shim 11 is made of a spring metal material (conductive metal thin plate) such as stainless steel or 42 alloy having a thickness of about 30 to 300 μm, and has rigidity for supporting the piezoelectric body 12. The shim 11 includes a terminal portion 11a extending outward from the circular portion. The piezoelectric body 12 is made of a piezoelectric material such as PZT (Pb (Zr, Ti) O ₃ ) having a thickness of about 50 to 600 μm, for example, and is polarized in the front and back directions. Such a piezoelectric vibrator is well known. The piezoelectric vibrator 10 may be a bimorph type having piezoelectric bodies 12 on both front and back sides of the shim 11.

  An O-ring 27 is elastically contacted with the periphery of the piezoelectric body 12 to maintain the liquid tightness of the pump chamber P. In this embodiment, an annular electrode (terminal) 29 is interposed between the piezoelectric body 12 and the O-ring 27 in order to supply power to the surface of the piezoelectric body 12 opposite to the shim 11. The annular electrode 29 is made of a spring metal material such as stainless steel, 42 alloy, phosphor bronze or the like having a thickness of about 10 to 30 μm. Like the shim 11, a terminal portion 29a extending outward from the annular portion is integrated. Have. The terminal portion 11a of the shim 11 and the terminal portion 29a of the annular electrode 29 are connected to power supply terminals 42 and 43 on the control board 40 via lead wires 11b and 29b. When an alternating electric field is applied to the front and back of the piezoelectric body 12 via the power supply terminals 42 and 43, 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) is in the center. It vibrates so that the amplitude of becomes the largest.

  The upper housing 22 is formed with a lid portion 22a for closing the substrate insertion opening 21b of the substrate storage space 21a, and an external terminal insertion hole (atmospheric flow hole) 22b (FIG. 1) is formed in the lid portion 22a. Yes.

  The piezoelectric pump with a built-in driver configured as described above is joined by sandwiching the piezoelectric vibrator 10, the O-ring 27, the annular contact member 28 and the annular electrode 29 between the main housing 21 and the upper housing 22. The lead wire 11b connected to the portion 11a and the lead wire 29b connected to the terminal portion 29a of the annular electrode 29 are led from the upper surface open portion 21c of the main housing 21 to the substrate storage space 21a, Connect to 43 (solder).

  In this state, when the control board 40 is inserted into the board storage groove 21d from the board insertion opening 21b of the board storage space 21a, the escape portion 45 of the control board 40 enters along the reinforcing column 21X of the main housing 21, and the control board 40 is inserted. The tip of each of them is in mechanical contact with the pair of inclined walls 21g linearly. The pair of linear contact portions serves as a swing fulcrum portion of the control board 40. As schematically shown in FIG. 5, the width d of the control board 40 is set to be smaller than the width D of the board housing groove 21d so that macro movement is possible in the board housing groove 21d. A gap s is secured. In the present embodiment, on both sides of the rear end portion (front side) of the control board 40 in the insertion direction, the rear end portion of the control board 40 is brought into the main housing 21 (board housing space 21a) by the adhesive AD filling the gap s. It is fixed. The adhesive AD has a vibration absorbing action, and for example, an acrylic resin adhesive, an epoxy resin adhesive, a silicone resin adhesive, a hot melt adhesive, or the like is used.

  As shown by a chain line in FIG. 5, the adhesive AD is interposed in a gap between the lid portion 22 a of the upper housing 22 that is then covered and fixed to the main housing 21 and the rear end wall of the control board 40. Also good. That is, the control board 40 can be pressed against the inner part of the board housing groove 21d by the lid 22a.

  In the piezoelectric pump having the above-described configuration, the upper wall 21f of the substrate housing groove 21d is moved to the bottom wall 21e side by the pressure applied to the liquid pump chamber P during the pumping action of applying an alternating electric field to the piezoelectric vibrator 10 via the control substrate 40. A force to deform is added. However, since the upper wall 21f and the bottom wall 21e are connected by the reinforcing column 21X, the deformation of the upper wall 21f is prevented. Further, during the pump action, the vibration of the piezoelectric vibrator 10 is transmitted to the main housing 21, and the vibration of the main housing 21 is transmitted to the control board 40. However, one end portion of the control substrate 40 (a tip portion positioned below the piezoelectric vibrator 10) is in mechanical line contact with the inclined wall 21g, and the rear end portion is provided with an adhesive AD having a vibration absorbing function. The vibration is not easily transmitted to the control board 40 because it is fixed to the wall surface of the board housing groove 21d (main housing 21). Further, the control board 40 can swing about the inclined wall 21g as viewed microscopically, is not easily twisted, and is a simple vibration. Therefore, an electrical component (electronic circuit part) installed on the control board 40 is used. It is possible to alleviate the damage to the solder 41 or the like in which the electrical components 41 and these electrical components 41 are connected to the printed wiring.

  FIG. 6 shows another support structure of the control board 40 with respect to the board housing groove 21d. This support structure is an embodiment in which the control substrate 40 and the upper wall 21f of the substrate storage groove 21d are brought into contact with each other by a pressing block 46 supported on the control substrate 40. The pressing block 46 may be omitted by narrowing the distance between the upper wall 21f and the bottom wall 21e of the substrate housing groove 21d in accordance with the thickness of the control substrate 40. The present embodiment is characterized in that a reinforcing support 21X is formed on the main housing 21, and an escape portion 45 that avoids the reinforcing support 21X is formed on the control board 40, and a support structure for the substrate storage groove 21d of the control board 40 is provided. Has a degree of freedom.

  In the above embodiment, the reinforcing column 21X is a single piece extending in the radial direction from the center of the liquid pump chamber P, but may be divided into a plurality of pieces. In this aspect, the plurality of reinforcing columns 21X are preferably provided in a direction parallel to the radial direction.

  In the above embodiment, the unimorph type piezoelectric vibrator having the piezoelectric body 12 on the front and back surfaces of the shim 11 is used and the piezoelectric body 12 is disposed toward the liquid pump chamber P side. The same power supply structure can be realized even if the rotation is reversed or a bimorph type or multimorph type piezoelectric vibrator is used.

  In the above embodiment, the terminal portion 11a of the shim 11 and the terminal portion 29a of the annular electrode 29 are electrically connected to the power supply terminals 42 and 43 of the control board 40 via the lead wires 11b and 29b. This power supply structure is an example. Thus, the present invention does not limit the feeding structure.

10 Piezoelectric vibrator 11 Shim (power supply member)
12 Piezoelectric body (piezoelectric layer)
20 Piezoelectric pump 21 Main housing 21a Substrate storage space 21b Substrate insertion opening 21c Upper surface opening portion 21d Substrate storage groove 21e Bottom wall 21f Upper wall 21g Inclined wall 21X Reinforcing strut 22 Upper housing 22a Lid portion 22b Air circulation hole 23 Check valve unit 24 Suction port 25 Discharge port 26 Circular recess 27 O-ring 28 Annular narrowing member 29 Annular electrode (power supply member)
30 Suction flow path 31 Discharge flow path 32 33 Check valve 40 Control board (drive control board)
41 Electrical parts (drive control parts)
42 43 Power supply terminal 45 Escape portion A Air chamber P Liquid pump chamber AD Adhesive s Gap

Claims (4)

In a single housing, a piezoelectric vibrator that forms a liquid pump chamber on at least one surface of the front and back, and a control board on which electric parts for power supply control for the piezoelectric vibrator are mounted, and the piezoelectric vibrator is vibrated. This is a piezoelectric pump with a built-in driver that performs the pumping action by supplying and discharging liquid into the liquid pump chamber,
In the housing, a part of the liquid pump chamber is overlapped in a plan view to form a substrate storage groove for storing the control substrate,
In this substrate storage groove, a reinforcing column is formed to connect to the opposing wall surface of the substrate storage groove, partially positioned in the overlapping portion,
A piezoelectric pump with a built-in driver, wherein an escape portion that avoids the reinforcing support is formed on the control board. The piezoelectric pump with a built-in driver according to claim 1, wherein the reinforcing column and the relief portion of the control board extend in a radial direction of the liquid pump chamber. The piezoelectric pump with a built-in driver according to claim 2, wherein the radial direction coincides with a direction in which the control board is inserted into the substrate housing groove. 4. The piezoelectric pump with a built-in driver according to claim 2, wherein the housing includes a main housing having a circular recess for storing a piezoelectric vibrator and a substrate storage space including the substrate storage groove, and the circular recess of the main housing and the substrate storage. A driver built-in piezoelectric pump including an upper housing that closes an open portion of the space.

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