JP7416324B2 - pump equipment - Google Patents

Description

The present invention relates to a pump device including a piezoelectric pump.

Patent Document 1 describes a blower that conveys fluid. The blower includes a pump section and a valve section. The pump section includes a piezoelectric element and a diaphragm. The piezoelectric element is attached to the diaphragm.

When a drive signal is applied to the piezoelectric element, the piezoelectric body of the piezoelectric element is distorted, and this distortion causes the diaphragm to vibrate. Thereby, the pump section transports the fluid.

At this time, the piezoelectric element generates heat due to application of a drive signal and distortion.

International Publication 2017/038565

When the piezoelectric element generates heat as described above, the temperature of the pump becomes unstable and its characteristics also become unstable.

Therefore, an object of the present invention is to stabilize the temperature of the pump even during the operation of the piezoelectric element.

The pump device of the present invention includes a piezoelectric pump and a heat storage member. A piezoelectric pump includes a flat plate having a piezoelectric element disposed on one main surface, and a housing in which the flat plate is disposed and supports the flat plate so as to vibrate. The heat storage member is arranged in the housing.

In this configuration, heat from the piezoelectric pump is stored in the heat storage member. The heat storage member maintains a substantially constant temperature by this heat. This also stabilizes the temperature of the piezoelectric pump in which the heat storage member is disposed.

According to this invention, the temperature of the pump can be stabilized even while the piezoelectric element is being driven, and the pump characteristics can be stabilized.

FIG. 1 is an exploded perspective view showing the configuration of a pump device according to a first embodiment. FIG. 2 is a schematic side cross-sectional view of the pump device according to the first embodiment, including fluid flow. FIG. 3 is a schematic graph showing an example of temperature change of a piezoelectric pump. FIG. 4 is a schematic side cross-sectional view of the pump device according to the second embodiment, including fluid flow. FIG. 5 is a schematic side view of a pump device according to a third embodiment. FIG. 6 is a side view of the pump device according to the fourth embodiment. FIG. 7 is a side view showing the configuration of a pump device according to the fifth embodiment.

[First embodiment]
A pump device according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an exploded perspective view showing the configuration of a pump device according to a first embodiment. FIG. 2 is a schematic side cross-sectional view of the pump device according to the first embodiment, including fluid flow. In addition, in the drawings shown in each embodiment including this embodiment, the shape of each component is partially or entirely exaggerated in order to make the configuration of the pump device easier to understand.

As shown in FIGS. 1 and 2, the pump device 1 includes a piezoelectric pump 10 and a heat storage member 51.

The piezoelectric pump 10 includes a pump body 20, a base housing 30, and a lid member 40. The base casing 30 and the lid member 40 constitute the "casing" of the present invention.

The pump body 20 includes a flat plate 211, a frame 212, a support portion 213, and a piezoelectric element 22. The flat plate 211 is circular in plan view. The frame 212 has a shape that surrounds the outer periphery of the flat plate 211 and is arranged at a position apart from the outer periphery of the flat plate 211. The support portion 213 is arranged between the flat plate 211 and the frame 212. The support portion 213 has a beam shape and supports the flat plate 211 with respect to the frame 212 so as to be able to vibrate.

The piezoelectric element 22 includes a disk-shaped piezoelectric body and a driving electrode. The piezoelectric element 22 is installed on one main surface of the flat plate 211. A drive signal is applied to the piezoelectric element 22 by a drive signal application electrode 251 and a drive signal application electrode 252.

The base housing 30 includes a main member 31 , a suction side nozzle 321 , a discharge side nozzle 322 , and a terminal placement part 35 . The main member 31, the suction side nozzle 321, the discharge side nozzle 322, and the terminal mounting portion 35 are integrally molded from, for example, an insulating resin material.

The main member 31 includes a bottom wall 311 and side walls 312. The main member 31 includes a recess 33 surrounded by a bottom wall 311 and side walls 312. The recess 33 includes a central recess 333 in plan view, a recess 332 disposed on the outer periphery of the central recess 333, and a recess 331 disposed on the outer periphery and in contact with the inner edge of the side wall 312. The recess 333 is deeper than the recess 332, and the recess 332 is deeper than the recess 331.

The suction side nozzle 321 and the discharge side nozzle 322 are attached to the outer surface of the side wall 312 of the main member 31. The suction port 3210 provided in the suction side nozzle 321 communicates with the recess 333 of the main member 31 through a through hole that penetrates the side wall 312 in the thickness direction. A discharge port 3220 provided in the discharge nozzle 322 communicates with the recess 332 through a through hole that penetrates the side wall 312 in the thickness direction.

The terminal placement portion 35 is arranged at a position on the outer surface of the side wall 312 of the main member 31 that is different from the position where the suction side nozzle 321 and the discharge side nozzle 322 are connected. The terminal mounting portion 35 has a shape that projects outward from the side wall 312 of the main member 31. One end of the drive signal application electrode 251 and the drive signal application electrode 252 is placed on the terminal placement portion 35 . The portions of the drive signal application electrode 251 and the drive signal application electrode 252 that are placed on the terminal placement portion 35 serve as a portion that supplies a drive signal from the outside.

The lid member 40 is a flat plate, and is made of metal, for example. The outer shape of the lid member 40 is substantially the same as the inner shape of the side wall 312 of the base housing 30, that is, the outer shape of the recess 331. Although the lid member 40 may be made of resin, it is preferably made of a material with higher thermal conductivity than the base housing 30, and more preferably made of metal as described above.

The pump body 20 is fitted into the recess 332 of the base housing 30. More specifically, the pump main body 20 is fitted so that the main surface of the flat plate 211 on which the piezoelectric element 22 is installed is opposite to the recess 331 . At this time, the frame 212 comes into contact with the surface of the recess 332 , and the flat plate 211 and the support section 213 do not come into contact with the recess 332 . That is, as shown in FIG. 2, a suction side space 101 is formed between the flat plate 211 and the support part 213 and the surface of the recessed part 331.

The lid member 40 is fitted into the recess 331 of the base housing 30. At this time, by adjusting the height of the recess 332, a discharge side space 102 is formed between the lid member 40 and the flat plate 211 and support portion 213 of the pump body 20, as shown in FIG. Ru. At this time, the pump main body 20 is arranged so that the flat plate 211, the support portion 213, and the piezoelectric element 22 do not come into contact with the lid member 40 due to the vibration of the flat plate 211.

With such a configuration, the pump main body 20 is arranged within the internal space of the housing with the flat plate 211 being able to vibrate. The outer surface of the wall on the suction side space 101 side (corresponding to the "second wall" in the present invention) of the housing becomes the suction side outer wall surface 130, and the wall on the discharge side space 102 side (corresponding to the "first wall" in the present invention) becomes the suction side outer wall surface 130. ”) becomes the discharge side outer wall surface 140.

When a drive signal is applied to the piezoelectric pump 10 having such a configuration by the drive signal application electrode 251 and the drive signal application electrode 252, the piezoelectric body of the piezoelectric element 22 is distorted, and the flat plate 211 undergoes bending vibration. This bending vibration mainly changes the pressure distribution in the suction side space 101.

Thereby, as shown by the thick arrow in FIG. 2, fluid (for example, air) flows into the suction side space 101 from the suction port 3210 of the suction side nozzle 321. The fluid that has flowed into the suction side space 101 is conveyed to the discharge side space 102 through the communication port 103 between the supporting parts 213 . The fluid conveyed to the discharge side space 102 is carried out to the discharge port 3220 of the discharge side nozzle 322, and is discharged to the outside.

At this time, as the piezoelectric element 22 is driven, the piezoelectric element 22 generates heat, and the temperature of the internal space of the housing increases. In particular, the temperature of the discharge side space 102 on the downstream side in the fluid transport direction tends to rise significantly.

The heat storage member 51 has a flat plate shape with a predetermined thickness and has heat storage properties. It is preferable that the heat storage member 51 is a latent heat storage material. For example, more specifically, the heat storage member 51 is a paraffin-based heat storage material, preferably normal paraffin, especially one with a melting point of 30° C. to 70° C., such as nonadecane, icosane, hemicosane, tetracosane, and triacontane. . Note that the heat storage member 51 is not limited to a latent heat storage material or a paraffin-based heat storage material, and may be any material that can maintain the temperature within a certain temperature range for a predetermined period of time.

For example, by using a latent heat storage material, the heat storage density of the heat storage member 51 can be increased, and a constant temperature can be maintained for a longer period of time. Furthermore, by using a paraffin-based heat storage material, it is possible to realize not only temperature retention ability but also weight reduction.

The heat storage member 51 is arranged on the discharge side outer wall surface 140 of the housing of the piezoelectric pump 10 . At this time, the heat storage member 51 has a shape that covers the entire surface of the discharge side outer wall surface 140.

In such a configuration, when the piezoelectric pump 10 is driven and generates heat, this heat is transmitted to the heat storage member 51.

The heat storage member 51 undergoes a phase change due to this heat, and stores the resulting transition heat (latent heat) as thermal energy. Thereby, the heat storage member 51 maintains a constant temperature over a predetermined period of time during which heat is applied.

In this way, when the heat storage member 51 reaches a constant temperature, the temperature of the piezoelectric pump 10 in which the heat storage member 51 is installed is also stabilized at a constant temperature.

FIG. 3 is a schematic graph showing an example of temperature change of a piezoelectric pump. In FIG. 3, the horizontal axis represents the elapsed time (time) from the start of driving the piezoelectric element 22, and the vertical axis represents the temperature of the piezoelectric pump 10, more specifically, the temperature of the discharge side outer wall surface 140. In FIG. 3, the solid line shows the case of the configuration of the present invention (with heat storage member), and the broken line shows the case of the comparative structure (without heat storage member).

As shown by the solid line in FIG. 3, when the heat storage member 51 is provided, the temperature of the piezoelectric pump 10 remains approximately constant over a predetermined period of time. On the other hand, when the heat storage member 51 is not provided, the temperature of the piezoelectric pump 10 increases unilaterally with elapsed time.

In this manner, the pump device 1 can maintain the piezoelectric pump 10 at a constant predetermined temperature by installing the heat storage member 51 in the piezoelectric pump 10. Thereby, the pump characteristics of the piezoelectric pump 10 can be stabilized.

Furthermore, the pump device 1 can prevent the piezoelectric pump 10 from becoming hotter than the temperature determined by the heat storage member 51. Thereby, the thermal stress of the piezoelectric pump 10 can be reduced, and a longer life can be realized. Note that the temperature determined by the heat storage member 51 is, for example, the temperature at which the phase changes from a solid phase to a liquid phase when the heat storage member 51 is a latent heat storage material. That is, the temperature determined by the heat storage member 51 is a temperature at which the heat storage member 51 can be maintained within a certain temperature range for a predetermined period of time.

Further, in the piezoelectric pump 10 having the above-described configuration, the discharge side space 102 is more likely to have a high temperature than the suction side space 101. Therefore, by disposing the heat storage member 51 on the discharge-side outer wall surface 140 of the piezoelectric pump 10, an increase in temperature can be effectively suppressed, and the temperature of the piezoelectric pump 10 can be more effectively stabilized.

Furthermore, in the above-described configuration, the heat storage member 51 is arranged on the entire surface of the discharge side outer wall surface 140. This improves the effect of heat storage as described above, compared to arranging the heat storage member 51 on a part of the discharge side outer wall surface 140. In other words, the above-described effect of heat storage can be obtained even with a configuration in which the heat storage member 51 is disposed on a part of the discharge side outer wall surface 140, but the effect is more effective by disposing the heat storage member 51 on the entire surface of the discharge side outer wall surface 140. It is possible to realize heat storage and stabilize the temperature of the piezoelectric pump 10 more reliably.

In addition, in this embodiment in which the heat storage member 51 is partially arranged, the heat storage member 51 may be arranged so as to overlap at least the piezoelectric element 22 when the pump device 1 is viewed from above. As mentioned above, the main heat generation source is the piezoelectric element 22. Therefore, by arranging the heat storage member 51 so as to overlap the piezoelectric element 22, the heat storage member 51 can store the heat generated within the piezoelectric pump 10 more efficiently and effectively.

Further, the heat storage member 51 may be not a latent heat storage material such as a paraffin-based heat storage material, but may be another heat storage material. However, by employing a latent heat storage material, the heat storage density of the heat storage member 51 can be increased, and the time for maintaining a constant temperature can be increased. Moreover, by employing a paraffin-based heat storage material, the weight of the heat storage member 51 can be reduced. Thereby, it is possible to realize a lightweight pump device 1 having stable pump characteristics.

Moreover, in the above-mentioned structure, the heat storage member 51 is preferably flexible. Thereby, even if the lid member 40 vibrates due to the vibration of the flat plate 211, the vibration can be absorbed by the heat storage member 51. From this, for example, the pump device 1 can suppress vibration noise.

At this time, it is preferable that the heat storage member 51 has a similar shape to the discharge side outer wall surface 140, and further, a similar shape to the lid member 40. As a result, vibrations are absorbed substantially uniformly in all directions centering on the piezoelectric element 22 when viewed from above. Therefore, the difference in vibration in each direction is suppressed, and distortion occurring in the housing can be suppressed. As a result, the reliability of the pump device 1 is improved.

Further, in this configuration, the suction side nozzle 321 and the discharge side nozzle 322 are arranged on the side wall 312 of the housing. Thereby, the opening surfaces of the suction port 3210 and the discharge port 3220 do not directly face the heat storage member 51. Therefore, the influence of the inhaled fluid and the discharged fluid on the heat storage member 51 can be suppressed. As a result, the temperature of the pump device 1 can be stabilized more reliably, and stable pump performance can be achieved more reliably.

[Second embodiment]
A pump device according to a second embodiment of the present invention will be described with reference to the drawings. FIG. 4 is a schematic side cross-sectional view of the pump device according to the second embodiment, including fluid flow.

As shown in FIG. 4, a pump device 1A according to the second embodiment differs from the pump device 1 according to the first embodiment in that a heat storage member 52 is added. The other configuration of the pump device 1A is the same as that of the pump device 1, and the explanation of the similar parts will be omitted.

The pump device 1A includes a heat storage member 52. The heat storage member 52 is made of the same material as the heat storage member 51, for example. Note that the heat storage member 52 may be made of a different material from the heat storage member 51, and may have a smaller heat storage capacity than the heat storage member 51.

The heat storage member 52 is arranged on the suction side outer wall surface 130 of the housing of the piezoelectric pump 10. At this time, the heat storage member 52 has a shape that covers the entire surface of the suction side outer wall surface 130.

With such a configuration, the pump device 1A can stabilize the temperature also on the suction side of the piezoelectric pump 10. Thereby, the pump device 1A can further stabilize the temperature of the piezoelectric pump 10.

Note that the shape of the heat storage member 51 and the shape of the heat storage member 52 may be the same or different.

[Third embodiment]
A pump device according to a third embodiment of the present invention will be described with reference to the drawings. FIG. 5 is a schematic side view of a pump device according to a third embodiment.

As shown in FIG. 5, a pump device 1B according to the third embodiment differs from the pump device 1 according to the first embodiment in that it includes a heat storage member 50. The other configuration of the pump device 1B is the same as that of the pump device 1, and the explanation of the similar parts will be omitted.

The pump device 1B includes a heat storage member 50. The heat storage member 50 is made of the same material as the heat storage member 51 according to the first embodiment.

The heat storage member 50 covers the outer surfaces of the suction side outer wall surface 130, the discharge side outer wall surface 140, and the side wall 312 of the piezoelectric pump 10.

With such a configuration, the pump device 1B stores heat on both main surfaces and two side surfaces that overlap the piezoelectric element 22 in the piezoelectric pump 10. Therefore, the pump device 1B can further stabilize the temperature of the piezoelectric pump 10.

In this embodiment, the heat storage member 50 is not arranged on the surface where the suction side nozzle 321 and the discharge side nozzle 322 of the piezoelectric pump 10 are formed. However, the heat storage member 50 may also be arranged on the surface where the suction side nozzle 321 and the discharge side nozzle 322 of the piezoelectric pump 10 are formed.

[Fourth embodiment]
A pump device according to a fourth embodiment of the present invention will be described with reference to the drawings. FIG. 6 is a side view of the pump device according to the fourth embodiment.

As shown in FIG. 6, a pump device 1C according to the fourth embodiment differs from the pump device 1 according to the first embodiment in that it includes a plurality of piezoelectric pumps and a plurality of heat storage members.

The pump device 1C includes a piezoelectric pump 10A, a piezoelectric pump 10B, and a connecting pipe 80. The piezoelectric pump 10A and the piezoelectric pump 10B have the same configuration as the piezoelectric pump 10 according to the first embodiment.

The piezoelectric pump 10A and the piezoelectric pump 10B are connected by a connecting pipe 80. More specifically, the discharge side nozzle 322A of the piezoelectric pump 10A and the suction side nozzle 321B of the piezoelectric pump 10B are connected by a connecting pipe 80. The discharge port of the discharge side nozzle 322A of the piezoelectric pump 10A and the suction port of the suction side nozzle 321B of the piezoelectric pump 10B communicate through the cavity of the connecting pipe 80.

In this configuration, piezoelectric pump 10A and piezoelectric pump 10B are driven. As a result, fluid is sucked into the piezoelectric pump 10A from the suction port of the suction side nozzle 321A of the piezoelectric pump 10A. The piezoelectric pump 10A discharges the sucked fluid into the connecting pipe 80 from the discharge port of the discharge side nozzle 322A of the piezoelectric pump 10A. The fluid discharged into the connecting pipe 80 is sucked into the piezoelectric pump 10B from the suction port of the suction side nozzle 321B of the piezoelectric pump 10B. The piezoelectric pump 10B discharges the sucked fluid to the outside from the discharge port of the discharge side nozzle 322B of the piezoelectric pump 10B.

With such a configuration, fluid is transported by the piezoelectric pump 10A and the piezoelectric pump 10B, so a larger flow rate can be achieved than when the piezoelectric pump 10A or the piezoelectric pump 10B is used alone.

At this time, as shown in FIG. 6, the piezoelectric pump 10A and the piezoelectric pump 10B are arranged so that the suction side outer wall surface 130A of the piezoelectric pump 10A and the suction side outer wall surface 130B of the piezoelectric pump 10B face each other. More specifically, in the piezoelectric pumps 10A and 10B, the suction side outer wall surface 130A of the piezoelectric pump 10A and the suction side outer wall surface 130B of the piezoelectric pump 10B face each other, are close to each other, and are substantially parallel to each other. It is arranged as follows.

In other words, the piezoelectric pump 10A is arranged such that the discharge side outer wall surface 140A faces the opposite side to the piezoelectric pump 10B side. The piezoelectric pump 10B is arranged so that the discharge side outer wall surface 140B faces the opposite side to the piezoelectric pump 10A side.

The heat storage member 51A is arranged on the discharge side outer wall surface 140A of the piezoelectric pump 10A. The heat storage member 51B is arranged on the discharge side outer wall surface 140B of the piezoelectric pump 10B. That is, in the pump device 1C, heat storage members 51A and 51B are arranged for each of the plurality of piezoelectric pumps 10A and 10B.

With such a configuration, the pump device 1C can stabilize the temperature even if it includes a plurality of piezoelectric pumps 10A and 10B, each of which serves as a heat source.

[Fifth embodiment]
A pump device according to a fifth embodiment of the present invention will be described with reference to the drawings. FIG. 7 is a side view showing the configuration of a pump device according to the fifth embodiment.

As shown in FIG. 7, the pump device 1D according to the fifth embodiment differs from the pump device 1C according to the fourth embodiment in the arrangement of the piezoelectric pump 10A and the piezoelectric pump 10B. The other configuration of the pump device 1D is the same as that of the pump device 1C, and a description of the similar parts will be omitted.

In the pump device 1D, the piezoelectric pump 10A and the piezoelectric pump 10B are arranged such that the discharge side outer wall surface 140A of the piezoelectric pump 10A and the discharge side outer wall surface 140B of the piezoelectric pump 10B face each other, are close to each other, and are substantially parallel to each other. will be placed.

The heat storage member 51D is sandwiched between the discharge side outer wall surface 140A and the discharge side outer wall surface 140B.

With such a configuration, the pump device 1D can stabilize the temperature even if it includes a plurality of piezoelectric pumps 10A and 10B, each of which serves as a heat source.

Note that in the fourth embodiment and the fifth embodiment, two piezoelectric pumps are provided. However, the configuration may include three or more piezoelectric pumps. When three or more piezoelectric pumps are provided, an individual heat storage member may be arranged in each piezoelectric pump, or a common heat storage member may be arranged in a plurality of piezoelectric pumps.

Furthermore, in each of the embodiments described above, the heat storage member is brought into direct contact with the piezoelectric pump. However, the heat storage member does not have to come into direct contact with the piezoelectric pump. For example, if a thermally conductive adhesive layer is placed between the heat storage member and the piezoelectric pump, or if there is a gap between the piezoelectric pump and the heat storage member that is large enough to allow heat to propagate from the piezoelectric pump to the heat storage member, good.

Note that the configurations of the above-described embodiments can be combined as appropriate, and effects can be achieved depending on the respective combinations.

1, 1A, 1B, 1C, 1D: Pump device 10, 10A, 10B: Piezoelectric pump 20: Pump body 22: Piezoelectric element 30: Base housing 31: Main member 33, 331, 332, 333: Recess 35: Terminal mounting Placement section 40: Lid members 50, 51, 51A, 51B, 51D, 52: Heat storage member 80: Connection pipe 101: Suction side space 102: Discharge side space 103: Communication ports 130, 130A, 130B: Suction side outer wall surface 140, 140A, 140B: Discharge side outer wall surface 211: Flat plate 212: Frame body 213: Support parts 251, 252: Drive signal application electrode 311: Bottom wall 312: Side wall 321, 321A, 321B: Suction side nozzle 322, 322A, 322B: Discharge Side nozzle 3210: Suction port 3220: Discharge port

Claims (6)

a piezoelectric pump comprising: a flat plate having a piezoelectric element disposed on its main surface; and a housing in which the flat plate is disposed and supports the flat plate in a vibrating manner;
a heat storage member disposed in the casing;
A pump device comprising: The casing includes a first wall and a second wall facing each other with the flat plate in between,
The heat storage member is arranged on at least one of the first wall and the second wall.
The pump device according to claim 1. The first wall faces the one main surface of the flat plate,
the heat storage member is disposed on the first wall;
The pump device according to claim 2. When viewed in plan from one principal surface to the other principal surface of the flat plate, the heat storage member is disposed at a position overlapping the piezoelectric element.
The pump device according to claim 3. The heat storage member is a latent heat storage material,
A pump device according to any one of claims 1 to 4. The heat storage member is a paraffin-based heat storage material,
The pump device according to claim 5.

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