JP7020645B2 - pump - Google Patents

Description

The present invention relates to a pump using an actuator made of a dielectric elastomer.

Conventionally, as this type of pump, for example, a diaphragm type pump as shown in Patent Document 1 is known. These pumps include a housing, a diaphragm that divides the housing into chambers 1 and 2, and a spring that connects the center of the diaphragm to the inner wall of the second chamber facing the center. There is. The diaphragm is composed of a film-type electrostraining and contracting polymer (actuator) capable of expanding and contracting the area due to contraction and expansion in the thickness direction due to fluctuations in the applied voltage and current.

In the first chamber, an intake port and an exhaust port arranged to face each other along the diaphragm are formed. The suction port is provided with a suction valve body that allows the fluid to enter the first chamber from the outside and prevents the fluid from flowing out from the first chamber to the outside. On the other hand, a discharge valve body is arranged at the discharge port, which prevents the fluid from entering the first chamber from the outside and allows the fluid to flow out from the first chamber to the outside.

Then, by repeatedly applying and stopping the voltage or current to the electrostrain stretchable polymer constituting the diaphragm, the diaphragm is moved between the first chamber and the second chamber by the stretch force of the electrostrain stretchable polymer and the urging force of the spring. Reciprocating flexion movement with. As a result, the fluid is supplied from the outside to the first chamber through the suction port, and the fluid is discharged from the first chamber to the outside through the discharge port.

Japanese Unexamined Patent Publication No. 2001-286162 (Fig. 6)

By the way, in the pump as described above, the peripheral portion of the diaphragm is supported by the housing and the central portion of the diaphragm is connected to the inner wall of the second chamber via a spring. The part between them is separated from the housing. Therefore, when the viscosity of the fluid is high or the discharge pressure is high, the diaphragm expands by receiving the reaction force from the fluid when pressing the fluid in the first chamber. As a result, the diaphragm does not operate as desired, so that there is a problem that the discharge of the fluid from the discharge port becomes unstable.

The present invention has been made by paying attention to the problems existing in such a conventional technique. An object of the present invention is to provide a pump capable of stably discharging a fluid from a discharge port regardless of the viscosity of the fluid.

Hereinafter, means for solving the above problems and their actions and effects will be described.
A pump that solves the above-mentioned problems includes a fluid chamber that communicates with both a suction port into which a fluid is sucked and a discharge port through which the fluid is discharged and can accommodate the fluid, and a storage chamber adjacent to the fluid chamber. A pair having a case having an annular sealing surface located at the boundary between the fluid chamber and the accommodation chamber, a dielectric layer accommodated in the accommodation chamber and made of a dielectric elastomer, and facing each other with a central portion of the dielectric layer interposed therebetween. The surface of the actuator facing the fluid chamber is provided with an actuator having an electrode layer made of a conductive elastomer, a first valve capable of opening and closing the suction port, and a second valve capable of opening and closing the discharge port. A fluid chamber forming surface including at least a central portion of the actuator and forming a part of the wall surface forming the fluid chamber, and a surface opposite to the fluid chamber forming surface in the actuator is the case. The gist is that the peripheral edge portion of the actuator on the fluid chamber forming surface side is fixed to the inner surface of the above and seals between the fluid chamber and the accommodating chamber in cooperation with the sealing surface.

According to this configuration, when a voltage is applied to the actuator, the fluid chamber forming surface is rapidly elastically deformed so as to be dented from a flat state, and when the voltage application to the actuator is stopped, the fluid chamber forming surface is the original before elastic deformation. It is quickly restored to the flat state of. In this case, since the surface of the actuator opposite to the fluid chamber forming surface is fixed to the inner surface of the case, the fluid chamber forming surface of the actuator is elastically deformed from the state of being elastically deformed so as to be depressed even when the fluid viscosity is high. It is stably restored to the previous flat state. Therefore, even when the viscosity of the fluid is high, the fluid in the fluid chamber can be smoothly pressurized by the fluid chamber forming surface, so that the fluid can be stably discharged from the discharge port regardless of the viscosity of the fluid.

In the pump, the case includes a fluid chamber case that defines the fluid chamber, a containment chamber case that defines the accommodation chamber, and an annular seal member that protrudes inward and is fixed to the fluid chamber case. It is preferable that the sealing surface is formed by the surface of the sealing member on the accommodation chamber side.

According to this configuration, the fluid chamber can be widened, so that the first valve and the second valve can be easily incorporated in the fluid chamber.
In the pump, the fluid chamber forming surface is preferably formed by a protective layer formed of a material having a lower permeability to the fluid than the material forming the dielectric layer.

According to this configuration, since the fluid chamber forming surface is formed by the protective layer, even a material having low resistance to fluid can be used as a material for forming the dielectric layer.
In the pump, the dielectric layer is preferably formed of crosslinked polyrotaxane.

According to this configuration, since the dielectric constant is higher than that when the dielectric layer is formed of, for example, a silicone elastomer, the expansion / contraction ratio of the actuator with respect to the applied voltage can be increased. Therefore, even when the voltage applied to the actuator is small, a relatively large amount of fluid can be transferred.

In the pump, the first valve and the second valve are preferably composed of an elastic body that opens and closes by elastically deforming due to a pressure change in the fluid chamber.
According to this configuration, the sound generated by opening and closing the valve body can be reduced.

According to the present invention, the fluid can be stably discharged from the discharge port regardless of the viscosity of the fluid.

The perspective view which shows the pump of one Embodiment. FIG. 1 is a cross-sectional view. Schematic diagram of the cross section of the actuator in the pump. Sectional drawing which shows the state when the fluid is sucked from the suction port of a pump. Sectional drawing which shows the state when the fluid is discharged from the discharge port of a pump.

Hereinafter, an embodiment of the pump will be described with reference to the drawings.
As shown in FIGS. 1 and 2, the pump 11 includes a case 12 having a substantially rectangular parallelepiped shape. The case 12 includes a first case 13 as an example of a storage chamber case defining the storage chamber 20, a second case 14 laminated on the first case 13, and a third case laminated on the second case 14. It is divided into 15. The first case 13, the second case 14, and the third case 15 are integrally connected by bolts 16 at these four corners.

In the present embodiment, the second case 14 and the third case 15 have almost the same thickness, and the first case 13 is about four times as thick as the second case 14 or the third case 15. .. The second case 14 and the third case 15 constitute a fluid chamber case that defines a fluid chamber 19 having a valve structure inside.

The third case 15 defines the upper portion of the fluid chamber 19 and is formed so that the cylindrical suction port 17 from which the fluid is sucked and the cylindrical discharge port 18 from which the fluid is discharged are paired with each other. ing. The second case 14 defines a side portion of the fluid chamber 19 to form a fluid chamber 19 that communicates with both the suction port 17 and the discharge port 18 and can accommodate the fluid sucked from the suction port 17. In the first case 13, a storage chamber 20 adjacent to and communicating with the fluid chamber 19 is formed.

The containment chamber 20 is formed almost entirely in the first case 13. A rigid bottom plate 21 is provided on the bottom surface of the first case 13 so as to cover the entire bottom surface. A columnar actuator 22 is fixed to the central portion of the bottom plate 21 by adhesive on the entire surface. The height (length in the axial direction) of the actuator 22 is substantially the same as the depth of the accommodation chamber 20. That is, the actuator 22 is housed in the central portion of the storage chamber 20. Therefore, a space 23 is formed between the peripheral surface of the actuator 22 and the inner surface of the first case 13. A hole 24 that communicates the inside and outside of the first case 13 is formed on one side wall of the first case 13. That is, the space 23 is open to the atmosphere through the hole 24.

As shown in FIG. 2, the surface of the actuator 22 facing the fluid chamber 19 includes a flat fluid chamber forming surface 22a including at least a central portion of the actuator 22 and forming a part of the wall surface forming the fluid chamber 19. It is said that. The fluid chamber forming surface 22a is formed by the protective layer 25. The protective layer 25 protects the first counter electrode layer 32, the second counter electrode layer 33, the dielectric layer 34, and the like, which will be described later, from the fluid in the fluid chamber 19. The surface of the actuator 22 on the opposite side of the fluid chamber forming surface 22a is fixed to the bottom surface (inner surface) in the first case 13 via the bottom plate 21.

Case 12 includes a second case 14 and a third case 15 constituting a fluid chamber case defining the fluid chamber 19, a first case 13 constituting an accommodation chamber case defining the accommodation chamber 20, and a second case 14. It includes an annular sealing member 26 that protrudes inward and is fixed. The surface of the sealing member 26 on the accommodation chamber 20 side is an annular sealing surface 26a located at the boundary between the fluid chamber 19 and the accommodation chamber 20. That is, the seal surface 26a is composed of the surface of the seal member 26 on the accommodation chamber 20 side.

Between the second case 14 and the third case 15, a first valve 27 that can open and close the suction port 17 and a second valve 28 that can open and close the discharge port 18 are arranged. The first valve 27 and the second valve 28 are composed of an elastic body 29 such as rubber that opens and closes by elastically deforming due to a pressure change in the fluid chamber 19. In the present embodiment, the first valve 27 and the second valve 28 are composed of one elastic body 29 formed in a substantially rectangular plate shape. That is, one end of the elastic body 29 in the longitudinal direction constitutes the first valve 27, and the other end constitutes the second valve 28.

The second case 14 is formed with a first recess 30 that allows elastic deformation when the first valve 27 operates to open the valve. The third case 15 is formed with a second recess 31 that allows elastic deformation when the second valve 28 operates to open the valve. Therefore, the first valve 27 is opened by elastically deforming toward the first recess 30 only when the fluid chamber 19 is depressurized, and the second valve 28 is opened only when the fluid chamber 19 is pressurized. The valve is opened by elastically deforming to the concave portion 31 side.

That is, the first valve 27 is a one-way valve that allows the fluid to enter the fluid chamber 19 from the suction port 17 and prevents the fluid from flowing out from the fluid chamber 19 to the suction port 17, and the second valve 28 is an exhaust valve. It is a one-way valve that blocks the ingress of fluid from the outlet 18 into the fluid chamber 19 and allows the outflow of fluid from the fluid chamber 19 to the discharge port 18.

As shown in FIG. 3, the actuator 22 is a piezoelectric element made of an elastomer, and the first counter electrode layer 32 and the second counter electrode layer 33 constituting the pair of conductive elastomer electrode layers are made of a dielectric elastomer. It is composed of a multi-layered structure that is alternately arranged so as to sandwich the central portion of the above. That is, the first counter electrode layer 32 and the second counter electrode layer 33 face each other so as to form a pair with the central portion of the dielectric layer 34 interposed therebetween.

The first counter electrode layer 32 and the second counter electrode layer 33 are formed in a thin film shape having a thickness of, for example, 1 to 100 μm. From the peripheral edges of the counter electrode layers 32 and 33, linear extension electrodes 32a and 33a connected to the external electric wire 36 extend to the peripheral surface of the actuator 22.

Therefore, in the actuator 22, both the first region A1 on the peripheral edge where the first counter electrode layer 32 and the second counter electrode layer 33 do not overlap, and both the first counter electrode layer 32 and the second counter electrode layer 33 are in the stacking direction. A central second region A2 that overlaps is provided. In this case, the sealing member 26 is sealed by pressure contacting the first region A1 on the fluid chamber forming surface 22a. That is, the peripheral edge portion of the actuator 22 on the fluid chamber forming surface 22a side seals between the fluid chamber 19 and the accommodating chamber 20 together with the sealing surface 26a. In this embodiment, the protective layer 25 is formed of a material having a lower fluid permeability than the material forming the dielectric layer 34.

The conductive elastomer (material of the first counter electrode layer 32 and the second counter electrode layer 33) constituting the first counter electrode layer 32 and the second counter electrode layer 33 is not particularly limited, and is a known elastomer piezoelectric element. The conductive elastomer used in the above can be used. Examples of the conductive elastomer include a conductive elastomer containing an insulating polymer and a conductive filler.

Examples of the insulating polymer include crosslinked polyrotaxane, silicone elastomer, acrylic elastomer, and urethane elastomer. One of these insulating polymers may be used, or a plurality of types may be used in combination. Examples of the conductive filler include metal particles such as Ketjen Black (registered trademark), carbon black, copper and silver. One of these conductive fillers may be used, or a plurality of types may be used in combination.

The dielectric layer 34 is formed in the form of a thin film having a thickness of, for example, 10 to 300 μm. The dielectric elastomer (material of the dielectric layer 34) constituting the dielectric layer 34 is not particularly limited, and a dielectric elastomer used in a known piezoelectric element made of an elastomer can be used.

Examples of the dielectric elastomer include crosslinked polyrotaxane, silicone elastomer, acrylic elastomer, and urethane elastomer. One of these dielectric elastomers may be used, or a plurality of types may be used in combination. The dielectric elastomer (material of the dielectric layer 34) constituting the dielectric layer 34 of the present embodiment is formed of crosslinked polyrotaxane.

An insulating portion 35 made of an insulating elastomer is provided in a region between the dielectric layers 34 adjacent to each other in the stacking direction in which the first counter electrode layer 32 and the second counter electrode layer 33 are not arranged. .. The thickness of the insulating portion 35 is the same as the thickness of the first counter electrode layer 32 and the second counter electrode layer 33.

As the insulating elastomer (material of the insulating portion 35) constituting the insulating portion 35, a known insulating elastomer used for the insulating portion in a known piezoelectric element made of elastomer or the like can be used. Examples of the insulating elastomer include crosslinked polyrotaxane, silicone elastomer, acrylic elastomer, and urethane elastomer. One of these insulating elastomers may be used, or a plurality of types may be used in combination.

The first counter electrode layer 32 and the second counter electrode layer 33 are electrically connected to the power supply 37 via the extension electrodes 32a and 33a and the electric wire 36. Therefore, a voltage is applied between the first counter electrode layer 32 and the second counter electrode layer 33 by the power supply 37.

Next, the operation of the pump 11 will be described.
As shown in FIGS. 3 and 4, when a voltage is applied to the actuator 22, the surface of the actuator 22 opposite to the fluid chamber forming surface 22a is fixed to the bottom plate 21, so that the actuator 22 has a fluid chamber forming surface. The second region A2 in 22a is elastically deformed so as to be recessed. Then, since the volume of the fluid chamber 19 increases, the pressure of the fluid chamber 19 is reduced. The depressurization of the fluid chamber 19 opens the first valve 27, and the fluid flows into the fluid chamber 19 from the suction port 17.

At this time, since the first region A1 of the actuator 22 is hardly elastically deformed, the sealed state by the sealing member 26 is maintained. Therefore, the fluid in the fluid chamber 19 does not enter the space 23 in the accommodating chamber 20 from between the sealing member 26 and the protective layer 25.

Subsequently, when the application of the voltage to the actuator 22 is stopped, as shown in FIG. 5, the fluid chamber forming surface 22a of the actuator 22, which has been elastically deformed so as to be dented, is in the original flat state before the elastic deformation due to the elastic restoring force. Return to. Then, the fluid in the fluid chamber 19 is pressurized by the actuator 22, the first valve 27 is closed, and the second valve 28 is opened. As a result, the fluid in the fluid chamber 19 flows to the discharge port 18 and is discharged to the outside.

Then, the pump 11 repeatedly applies the voltage to the actuator 22 and stops the application of the voltage to the actuator 22, thereby sucking the fluid from the suction port 17 and discharging the fluid from the discharge port 18. Repeat. In this case, the actuator 22 is only deformed so that the second region A2 on the fluid chamber forming surface 22a, which is the surface opposite to the surface fixed to the bottom plate 21, is repeatedly dented and returned to a flat state. Therefore, even when the viscosity of the fluid is high, the deformation operation is stable with high reproducibility. Therefore, the pump 11 can stably discharge the fluid in the fluid chamber 19 from the discharge port 18 regardless of the viscosity of the fluid.

(Change example)
The above embodiment may be changed as follows.
-The first valve 27 and the second valve 28 do not necessarily have to be composed of the elastic body 29. That is, the first valve 27 and the second valve 28 may be configured by, for example, a ball valve used in Patent Document 1 or another general one-way valve.

-The protective layer 25 may be omitted.
The entire surface of the actuator 22 may be covered with the protective layer 25.
-As the fluid chamber case, a case may be adopted in which the second case 14 and the third case 15 are integrated and a flange portion extending outward from the lower end peripheral edge thereof is formed. In this case, by extending the accommodation chamber 20 and the actuator 22 to the lower surface of the flange portion, the lower surface of a part of the flange portion can be used as a sealing surface, so that the sealing member 26 can be omitted.

The number of laminated dielectric layers 34 in the actuator 22 and the area of the fluid chamber forming surface 22a may be appropriately changed. By doing so, the suction amount (suction pressure) of the fluid from the suction port 17 and the discharge amount (discharge pressure) of the fluid from the discharge port 18 can be adjusted, so that the pump 11 has a desired specification. Can be done.

The drive speed and stroke of the actuator 22 may be controlled by the control unit.
In the above embodiment, the lower surface of the actuator 22 is adhered to the bottom plate 21 and the bottom plate 21 is arranged on the bottom surface in the first case 13, but the bottom plate 21 is omitted and the lower surface of the actuator 22 is directly placed on the bottom surface in the first case 13. It may be adhered to and fixed to. Further, the lower surface of the actuator 22 may be fixed to the lower surface in the first case 13 by using a negative pressure such as a suction cup. By doing so, the actuator 22 can be easily fixed to the bottom surface in the first case 13 only by pressing the lower surface of the actuator 22 against the bottom surface in the first case 13.

11 ... Pump, 12 ... Case, 13 ... First case constituting the storage chamber case, 14 ... Second case constituting the fluid chamber case, 15 ... Third case constituting the fluid chamber case, 17 ... Suction port, 18 ... Discharge port, 19 ... Fluid chamber, 20 ... Containment chamber, 22 ... Actuator, 22a ... Fluid chamber forming surface, 25 ... Protective layer, 26 ... Sealing member, 26a ... Sealing surface, 27 ... First valve, 28 ... Second Valve, 29 ... elastic body, 32 ... first counter electrode layer constituting the electrode layer, 33 ... second counter electrode layer constituting the electrode layer, 34 ... dielectric layer.

Claims (4)

A fluid chamber that communicates with both the suction port where the fluid is sucked and the discharge port from which the fluid is discharged and can accommodate the fluid, an accommodation chamber adjacent to the fluid chamber, and the fluid chamber and the accommodation chamber. A case with an annular sealing surface located at the boundary of
An actuator housed in the storage chamber and having a dielectric layer made of a dielectric elastomer and a pair of electrode layers made of conductive elastomer facing each other with a central portion of the dielectric layer interposed therebetween.
The first valve that can open and close the suction port and
A second valve that can open and close the discharge port,
Equipped with
The surface of the actuator facing the fluid chamber is a fluid chamber forming surface including at least a central portion of the actuator and forming a part of the wall surface forming the fluid chamber.
The surface of the actuator opposite to the fluid chamber forming surface is fixed to the inner surface of the case.
The peripheral edge portion of the actuator on the fluid chamber forming surface side seals between the fluid chamber and the accommodating chamber in cooperation with the sealing surface .
The case is
The fluid chamber case that defines the fluid chamber and
A containment chamber case that defines the containment chamber, and a containment chamber case.
An annular sealing member that protrudes inward and is fixed to the fluid chamber case,
Equipped with
The pump is characterized in that the sealing surface is formed by a surface of the sealing member on the accommodation chamber side . The pump according to claim 1, wherein the fluid chamber forming surface is formed by a protective layer formed of a material having a lower permeability to the fluid than the material forming the dielectric layer. The pump according to claim 1 or 2 , wherein the dielectric layer is formed of a crosslinked polyrotaxane. One of claims 1 to 3 , wherein the first valve and the second valve are composed of an elastic body that opens and closes by elastically deforming due to a pressure change in the fluid chamber. The pump described in the section.

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