JP2009250028A - 4-valve piezoelectric pump with built-in driver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To attain miniaturization and thinning to a limit, while satisfying a UL standard, in a 4-valve piezoelectric pump with built-in driver for respectively arranging suction side and delivery side check valves between a pair of pump rooms and a single suction port and between the pair of pump rooms and a single delivery port on the obverse-reverse of a piezoelectric vibrator, by storing a control board mounted with the piezoelectric vibrator and a power supply controlling electric part to the piezoelectric vibrator in a housing. <P>SOLUTION: This 4-valve piezoelectric pump with built-in driver is provided so that the suction port and the delivery port extending in the parallel direction to a reference bottom surface are projected in one end part of one of a pair of housings having a sandwiching surface for sandwiching the piezoelectric vibrator, and the sandwiching surface of this port housing is inclined in the direction for separating from the reference bottom surface for separating from the suction port and the delivery port, and is positioned in an end part on the opposite side of the suction port and the delivery port in the port housing, and a control board storage space is formed so that at least a part overlaps in a plan view with the piezoelectric vibrator and the pump room. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a four-valve piezoelectric pump that obtains a pump action by a vibrating piezoelectric vibrator, and more particularly to a driver-embedded four-valve piezoelectric pump that houses a control board on which a power supply control electrical component for the piezoelectric vibrator is mounted in a housing.

  The 4-valve piezoelectric pump forms pump chambers on the front and back sides (upper and lower sides) of the piezoelectric vibrator, while providing a single suction port and a single discharge port between the pair of pump chambers and the suction port. First and second suction-side check valves that allow fluid flow from the suction port to the pair of pump chambers but do not allow fluid flow in the opposite direction are provided between the pair of pump chambers and the discharge port. First and second discharge-side check valves are provided that allow fluid flow from the pair of pump chambers to the discharge port but do not allow fluid flow in the opposite direction (Patent Document 4).

In this four-valve piezoelectric pump with a built-in driver, when the piezoelectric vibrator is vibrated, one volume of the pair of pump chambers is enlarged and the other volume is reduced. Therefore, even when the piezoelectric vibrator vibrates forward or backward. The operation of closing one of the pair of check valves and opening the other is repeated to obtain a pumping action. Compared with a two-valve piezoelectric vibrator pump in which a pump chamber is provided only on one of the front and back sides of the piezoelectric vibrator, high efficiency (high flow rate) can be achieved by halving the pulsation cycle.
JP-A-6-288355 JP 2004-060640 A Special Table 2004-517240 JP 2005-337068 A JP 2006-299962 JP 2007-071099

  In order to reduce the size of the four-valve piezoelectric pump that is excellent in principle as described above, a driver built-in type in which a piezoelectric vibrator and a driving substrate (driver) that applies a driving voltage to the piezoelectric vibrator are housed in the same housing. Is a good idea. However, since the drive substrate that applies the drive voltage to the piezoelectric vibrator generates a high voltage, it is difficult to satisfy the UL standard if it is built in the housing of the piezoelectric pump.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to obtain a driver-embedded four-valve piezoelectric pump that satisfies the UL standard and is extremely small and thin. It is another object of the present invention to obtain a driver built-in four-valve piezoelectric pump capable of constructing a substantial flow path structure by assembling a pair of housings sandwiching a piezoelectric vibrator.

  According to the present invention, a piezoelectric vibrator that forms pump chambers on the front and back sides of a housing and a control board on which electric parts for power supply control for the piezoelectric vibrator are mounted are housed in a housing. A pair of first and second suction side check valves are provided between the ports and the first and second suction side check valves that allow fluid flow from the suction port to the pair of pump chambers but do not allow fluid flow in the opposite direction. A first discharge valve and a second discharge side check valve that allow fluid flow from the pair of pump chambers to the discharge port and do not allow fluid flow in the opposite direction between the first discharge port and the single discharge port. In a 4-valve piezoelectric pump with a built-in driver that vibrates a vibrator and obtains a pump action, the housing is composed of a pair of housings having a sandwiching surface for sandwiching the piezoelectric vibrator, and one end of one of the pair of housings. Part of the The suction port and the discharge port extending in a direction parallel to the reference bottom surface of the ring are projected, and the holding surface of the port housing having the suction port and the discharge port is separated from the reference bottom surface as the distance from the suction port and the discharge port increases. The piezoelectric vibrator plane is inclined with respect to the reference bottom surface by being inclined away from the reference bottom surface, and is positioned on the opposite end of the suction port and the discharge port on the ported housing, and at least a part of the piezoelectric vibrator and the pump chamber And a storage space for the control board that overlaps in plan view.

  The wall thickness forming the control board storage space of the ported housing should be non-uniform.

  In the non-port housing, it is desirable that the wall thickness in the direction along the radial direction of the piezoelectric vibrator is non-uniform, and the thickness is increased toward the suction port and the discharge port.

  Both the pair of housings can be formed of a molded product of a synthetic resin material.

  The piezoelectric vibrator has an alternately laminated structure of at least one shim made of a conductive metal thin plate and at least one piezoelectric layer.

  According to the four-valve piezoelectric pump with a built-in driver of the present invention, the suction port and the discharge port extending in a direction parallel to the reference bottom surface of the housing are protruded from one end of the pair of housings sandwiching the piezoelectric vibrator. The piezoelectric vibrator clamping surface of the port housing with a port is inclined in a direction away from the reference bottom surface as the distance from the suction port and the discharge port is increased, and the piezoelectric vibrator plane is inclined with respect to the reference bottom surface (non-parallel). The control board storage space is formed in the port housing with the control board storage space positioned at the opposite end of the suction port and the discharge port and at least partially overlapping the piezoelectric vibrator and the pump chamber in plan view. It is possible to achieve a reduction in size and thickness while ensuring a sufficient thickness of the wall surface forming the space and satisfying the UL standard.

  First, with reference to FIG. 8, the operation principle of the driver-embedded 4-valve piezoelectric pump will be described. The piezoelectric vibrator pump includes an upper housing 10, a lower housing 20, a piezoelectric vibrator 30, and four umbrellas (check valves) 11, 12, 21, and 22 as basic components. An upper pump chamber (variable volume chamber) 13 and a lower pump chamber (variable volume chamber) 23 are formed between the upper housing 10 and the piezoelectric vibrator 30, and between the lower housing 20 and the piezoelectric vibrator 30, respectively. The single suction port 31 communicates with the suction side flow paths 14H and 24H, the suction side flow path 14H communicates with the upper pump chamber 13 via the suction side check valve 11, and the suction side flow path 24H It communicates with the lower pump chamber 23 via the side check valve 21. The single discharge port 32 communicates with the discharge-side flow path 15D and the discharge-side flow path 25D, and the discharge-side flow path 15D communicates with the upper pump chamber 13 via the discharge-side check valve 12. The side flow path 25D communicates with the lower pump chamber 23 via the discharge side check valve 22.

  In the four-valve piezoelectric pump with a built-in driver, when the piezoelectric vibrator 30 is elastically deformed (vibrated) in the forward and reverse directions, the volume of one of the upper pump chamber 13 and the lower pump chamber 23 increases and the other volume decreases. The stroke in which the volume of the upper pump chamber 13 increases is the stroke in which the volume of the lower pump chamber 23 decreases. Since the volume of the upper pump chamber 13 increases, the suction side check valve 11 opens and fluid flows from the suction port 31 into the upper pump chamber 13. Flows in and the volume of the lower pump chamber 23 decreases, so that the fluid in the lower pump chamber 23 opens the discharge side check valve 22 and flows out to the discharge port 32 (FIG. 8B). Conversely, the stroke in which the volume of the upper pump chamber 13 decreases is a stroke in which the volume of the lower pump chamber 23 increases. Since the volume of the lower pump chamber 23 increases, the suction side check valve 21 opens and the suction port 31 opens into the lower pump chamber 23. Since the fluid flows into the upper pump chamber 13 and the volume of the upper pump chamber 13 decreases, the fluid in the upper pump chamber 13 opens the discharge-side check valve 12 and flows out to the discharge port 32 (FIG. 8A). Therefore, the pulsation cycle at the discharge port 32 can be shortened (halved compared to the case where the pump chamber is formed only on one of the upper and lower sides of the piezoelectric vibrator 30).

  In this embodiment, the driver built-in four-valve piezoelectric pump having the above operation principle is realized with a small (thin) simple structure, and FIGS. 1 to 7 show the first embodiment. In FIG. 1 to FIG. 7, the same reference numerals are given to the same components as those in FIG.

  The driver-embedded four-valve piezoelectric pump of this embodiment includes a port housing 10 having a suction port 31 and a discharge port 32, and a non-port housing 20 that does not have these ports. The ported housing 10 has a reference bottom surface 10B, and the suction port 31 and the discharge port 32 protrude in parallel to one end of the ported housing 10 and in parallel to the reference bottom surface 10B. On the opposite side of the reference bottom surface 10 </ b> B of the ported housing 10, a clamping surface 10 </ b> S for clamping the piezoelectric vibrator 30 is formed. The sandwiching surface 10S is not parallel to the reference bottom surface 10B, and is inclined in a direction away from the reference bottom surface 10B as the distance from the suction port 31 and the discharge port 32 increases. The inclination angle θ (FIG. 2) is, for example, 3 ° ± 1 °.

  The port housing 10 is formed with a recess 13a that forms a pump chamber 13, and a suction-side flow path 14H and a discharge-side flow path 15D that communicate with the recess 13a. The suction-side flow path 14H and the discharge-side flow The passage 15D communicates with the suction port 31 and the discharge port 32.

  The port housing 10 is also formed with suction connection protrusions 16H and discharge connection protrusions 16D projecting toward the non-port housing 20 side at the end on the side having the suction port 31 and the discharge port 32. A suction connection channel 14Ha that communicates with the suction side channel 14H and a discharge connection channel 15Da that communicates with the discharge side channel 15D are formed at the center of the suction connection projection 16H and the discharge connection projection 16D. The suction connection projection 16H and the discharge connection projection 16D are rectangular in shape, and a suction connection slope 16Ha and a discharge connection slope 16Da that are inclined at an appropriate angle with respect to the axial direction are formed at the front ends thereof.

  The non-port housing 20 is formed with a recess 23a that forms a pump chamber 23, and a suction-side channel 24H and a discharge-side channel 25D that communicate with the recess 23a. Recesses 26H and 26D (FIG. 3) into which the suction connection protrusion 16H and the discharge connection protrusion 16D of the port housing 10 are fitted are formed at the end of the non-port housing 20, and the inner parts of the recesses 26H and 26D are formed. Further, a suction side connection slope 26Ha and a discharge connection slope 26Da corresponding to the suction connection slope 16Ha and the discharge connection slope 16Da of the port housing 10 are formed. The ported housing 10 and the portless housing 20 described above can be easily molded from a synthetic resin material.

  The suction connection projection 16H and the discharge connection projection 16D of the port housing 10 are fitted into the recesses 26H and 26D of the non-port housing 20, respectively, between the suction connection slopes 16Ha and 26Ha, and between the discharge connection slopes 16Da and 26Da, respectively. When the O-ring 27 is sandwiched, a liquid-tight flow path on the suction side and the discharge side is completed.

  The check valves 11 and 12 are provided at the end of the non-port housing 20 on the suction side flow path 24H and the discharge side flow path 25D on the recess 23a side, and the check valves 21 and 22 are provided on the suction side of the port housing 10 It is provided at the end of the flow path 14H and the discharge side flow path 15D on the recess 13a side. The check valves 11, 12, 21, and 22 in the illustrated embodiment are umbrella valves of the same form, and as shown in FIG. 6, an elastic material is attached to the perforated substrate 41 that is bonded or welded to the flow path. Umbrella 42 is installed. FIG. 6 depicts the discharge-side check valves 12 and 22, but the flow directions of the suction-side check valves 11 and 21 are opposite to those in the illustrated example.

  The piezoelectric vibrator 30 is held in a liquid-tight manner via an O-ring 33 between the sandwiching surface 10S of the port housing 10 and the sandwiching surface 20S of the non-port housing 20, and between the recess 13a. The pump chamber 13 is comprised and the pump chamber 23 is comprised between the recessed parts 23a. The piezoelectric vibrator 30 has an alternately laminated structure of at least one shim made of a conductive metal thin plate and at least one piezoelectric layer, and vibrates forward and backward by applying an alternating electric field to the piezoelectric layer. In this embodiment, the configuration of the piezoelectric vibrator 30 is not limited. For example, any type of unimorph and bimorph may be used.

  In the present embodiment, the clamping surface 10S of the port housing 10 and the clamping surface 20S of the non-port housing 20 are inclined in a direction away from the reference bottom surface 10B of the port housing 10 as they are separated from the suction port 31 and the discharge port 32. is doing. The port housing 10 is formed with a storage recess 18 for storing the control board 50 at the end opposite to the suction port 31 and the discharge port 32.

  As shown in FIGS. 4 and 5, an electrical component 53 that controls power feeding to the piezoelectric vibrator 30 and a printed wiring (not shown) that connects the electrical components 53 are formed on the drive substrate 50. Yes. The printed wiring is connected to the piezoelectric vibrator 30 by a power supply line (not shown), and supplies a driving high voltage to the piezoelectric layer of the piezoelectric vibrator 30.

  The housing recess 18 is provided at the end of the ported housing 10 (the end opposite to the suction port 31 and the discharge port 32) that secures a height by using an inclined arrangement with respect to the reference bottom surface 10B of the piezoelectric vibrator 30. Therefore, a large volume can be easily secured without increasing (thickening) the entire ported housing 10. Further, at least a part of the inner end portion of the storage recess 18 reaches a position overlapping with the piezoelectric vibrator 30 and the pump chamber 13 (23) in plan view, so that the size is reduced. Thus, even if a part of the inner end portion of the storage recess 18 is extended to a position overlapping the piezoelectric vibrator 30 and the pump chamber 13 (23) in plan view, the reference bottom surface 10B of the piezoelectric vibrator 30 is inclined. Thus, it is possible to sufficiently secure the thickness of the wall surface 18S (FIG. 6) that separates the pump chamber 13 (23) and the storage recess 18 from each other. For this reason, even the thin port housing 10 can satisfy the UL standard.

  Furthermore, in the illustrated embodiment, the thickness of the bottom wall 18W (FIG. 6) of the housing recess 18 of the port housing 10 and the thickness of the wall surface 20W of the portless housing 20 in the direction along the radial direction of the piezoelectric vibrator 30 are set. Non-uniform (non-uniform). More specifically, the bottom wall 18 </ b> W increases in thickness as it goes deeper into the housing recess 18, and the wall surface 20 </ b> W of the non-port housing 20 increases in thickness toward the suction port 31 and the discharge port 32. . Thus, by making the wall thickness of the housing non-uniform, it is possible to reduce the possibility of resonance during pump operation (during vibration of the piezoelectric vibrator 30) and to prevent generation of noise.

  In the four-valve piezoelectric pump with a built-in driver according to this embodiment, the piezoelectric vibrator 30 is sandwiched between an inclined sandwiching surface 10S of the port housing 10 and the tilted sandwiching surface 20S of the portless housing 20 via an O-ring 33. The suction connection projection 16H and the discharge connection projection 16D of the port housing 10 are fitted into the recesses 26H and 26D of the non-port housing 20, and between the suction connection slopes 16Ha and 26Ha and between the discharge connection slopes 16Da and 26Da. A four-valve piezoelectric pump with a liquid-tight structure can be obtained simply by assembling the O-ring 27. Positioning of the port housing 10 and the non-port housing 20 can be performed by a positioning hole 19A provided in the port housing 10 and a positioning projection 19B (FIGS. 5, 1 and 7) provided in the non-port housing 20. .

  In addition, the control board 50 is inserted into the housing recess 18 of the port housing 10 before the non-port housing 20 is coupled, and the power supply terminal is connected to the piezoelectric layer of the piezoelectric vibrator 30. Thereafter, when the non-port housing 20 is coupled to the port housing 10, the lid portion 28 of the non-port housing 20 closes the housing recess 18, thereby satisfying the UL standard. As shown in FIG. 4, the lid 28 is provided with a power supply port 29.

  In the above embodiment, both the suction port 31 and the discharge port 32 are provided in one of the pair of housings (ported housing 10), but both ports are formed in the other housing (portless housing 20). It is also possible to provide a port housing having a port, or it is possible to provide one port for each of the housing 10 and the housing 20 and to make both housings a port housing having a port. The rule at that time is a rule that a suction port is provided in the ported housing on the side having the suction side flow passage projection, and a discharge port is provided in the ported housing on the side having the discharge side flow passage projection.

It is a top view which shows embodiment which applied the 4-valve piezoelectric pump with a built-in driver by this invention to the piezoelectric pump. It is the same front view. It is the left side view. It is the same right view. It is sectional drawing which follows the VV line of FIG. It is sectional drawing which follows the VI-VI line of FIG. It is a top view including the cross section which follows the VII-VII line of FIG. (A) and (B) are skeleton diagrams showing the principle of a driver-embedded four-valve piezoelectric pump.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Port housing 10B Reference | standard bottom face 10S 20S Clamping face 11 12 21 22 Check valve 13 Pump chamber 13a Recess 14H 24H Suction side flow path 15D 25D Discharge side flow path 16H Suction connection protrusion 16D Discharge connection protrusion 16Ha Suction connection slope 16Da Discharge Connection slope 18 Storage recess 20 Portless housing 23 Pump chamber 23a Recess 26H 26D Recess 26Ha 26Da Inlet side connection slope 27 O-ring 28 Lid 30 Piezoelectric vibrator 31 Suction port 32 Discharge port 33 O-ring 50 Control board

Claims (5)

In the housing, a piezoelectric vibrator that forms pump chambers on the front and back sides thereof and a control board on which electric parts for power supply control for the piezoelectric vibrator are mounted are housed between the pair of pump chambers and a single suction port. Are provided with first and second suction-side check valves that allow fluid flow from the suction port to the pair of pump chambers but do not allow fluid flow in the opposite direction. First and second discharge-side check valves that allow fluid flow from the pair of pump chambers to the discharge port and do not allow fluid flow in the opposite direction are provided between the discharge ports and the piezoelectric vibrator. In the 4-valve piezoelectric pump with a built-in driver to obtain
The housing is composed of a pair of housings having a sandwiching surface for sandwiching the piezoelectric vibrator,
The suction port and the discharge port extending in a direction parallel to the reference bottom surface of the housing are protruded from one end of one housing of the pair of housings,
Inclining the piezoelectric vibrator plane with respect to the reference bottom surface by inclining the clamping surface of the ported housing having the suction port and the discharge port away from the reference bottom surface as the distance from the suction port and the discharge port increases.
A housing space for the control board is formed in the ported housing at the end opposite to the suction port and the discharge port, and at least a part thereof overlaps the piezoelectric vibrator and the pump chamber in plan view. 4-valve piezoelectric pump with built-in driver. 2. The driver built-in piezoelectric pump according to claim 1, wherein the wall surface forming the control board housing space of the port housing has a non-uniform wall thickness. 3. The piezoelectric pump with a built-in driver according to claim 1, wherein the non-port housing without the suction port and the discharge port has a non-uniform wall thickness in a direction along a radial direction of the piezoelectric vibrator. And a 4-valve piezoelectric pump with a built-in driver that increases the wall thickness toward the discharge port. 4. The driver built-in four-valve piezoelectric pump according to claim 1, wherein both of the pair of housings are made of a synthetic resin material. 5. The four-valve piezoelectric pump with a built-in driver according to claim 1, wherein the piezoelectric vibrator has an alternately laminated structure of at least one shim made of a conductive metal thin plate and at least one piezoelectric layer. 4-valve piezoelectric pump with built-in driver.

Images