JPS6088882A - Electrostriction pump - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to improvements in pumps and liquid displacement devices, and more particularly to devices using electrostrictive drive members.

[Prior art]

There are many applications in which it is desirable to have very precise control of the amount of fluid pumped or displaced or the discharge rate or displacement rate. In many of these and other applications, the displacement or flow rate is very small.

Various mechanisms have been devised to achieve such accurate or small displacement and discharge amounts. Such mechanisms include oscillating pumps, piston pumps, diaphragm pumps, and the like. However, all of these pumps are subject to common limitations. That is, they must rely on a rotary electric motor or solenoid as their driving source.

For many applications, motors and solenoids are costly and bulky, and difficult to accommodate in the housing in which they are mounted.

Accurate flow control is almost impossible using a prime mover. Accurate flow control using a prime mover often requires the provision of some other mechanism at the expense of additional cost and space.

[Summary of the invention]

It is an object of the present invention to provide an improved pump drive structure) and an improved pumping device and fluid displacement device.

Another object of the invention is to provide an improved variable stroke pump and fluid displacement device.

Yet another object of the invention is to provide a pump that operates accurately and is inexpensive. As an example of the application of the invention, the invention provides an indicator which consumes only a small amount of power and which is capable of displaying the liquid level like a thermometer;
It makes it possible to manufacture voltmeters and other devices.

In another application, the present invention makes it economically possible to provide a blower for cooling individual low power semiconductors in electronic equipment.

These are only examples of the wide range of applications of the present invention.Characteristics, advantages, embodiments, and applications of the present invention will become clear from the following description with reference to the drawings. It takes advantage of stroke capabilities and/or variable frequency capabilities. In a preferred embodiment of the present invention, the high Q value of the electrostrictive element is utilized to create a bon! Minimize the stroke of parts.

By changing the shape of a fluid container (whether a reservoir or part of a flow path), the present invention can change the shape of the walls of the container or change the volume of objects within the container. In particular, an electrostrictive element is used to change the volume. In an application as a fluid displacement device, an electrostrictive element is used to change the volume of a reservoir. In the application example as a pump,
Varying the dimensions and volume of the pumping space.

〔Example〕

Electrostrictive materials are available in plate form and can be easily bonded from one plate to another using a metal-filled conductive adhesive. If two electrostrictive plates are stacked and the polarities of the layers are reversed, the dimensions of one electrostrictive plate will increase and the dimensions of the other will decrease when placed in an electric field (bimol electrostrictive element).

As a result, a slight bend or warp occurs. In the case of a multilayered electrostrictive disk (multimolar electrostrictive element), when an alternating electric field is applied in the thickness direction of the disk, the disk will first move to one side of the central plane of its thickness in its central region. It bulges out and then bulges out on the other side. By changing the polarity of the electrostrictive element, the dimensions of the electrostrictive element, ie, its length or wall thickness, and therefore its volume, can be changed without bending or warping.

Such an electrostrictive element is used in cases where the relationship between electric field strength and change must be linear.

Although it is entirely possible to use a shape other than a disc shape in the present invention as the shape of the electrostrictive element, a disc shape is preferred in most applications. This is because, if the electric field strength across the disk changes for a given value, the volume change (repulsion amount) from the position occupied when the electric field strength is zero becomes the maximum. When used as a diaphragm in a diaphragm pump, the electrostrictive disk can generate a transient fluid flow. Also, when applied as a single stroke device, the disc-shaped electrostrictive element can displace a sufficient amount of fluid to indicate the strength of the electric field that causes a dimensional change in the electrostrictive element. In such applications, it may be preferable in some cases to use the electrostrictive polarization phenomenon to cause a change in the thickness of the electrostrictive element, rather than using bending or reversing action. Although the thickness change causes only a small volume change, this change is linear with respect to the electric field strength. Typically, a disk of electrostrictive material with a diameter of 3 CrrL and a thickness of 200 microns will produce a voltage of 40 V across a conductive layer on each side of the disk when an electric field strength of 200 V/mm is applied. When λ is applied, it will warp by an average of 7 microns from its free relaxation surface.

The degree of dimensional change is sufficient to provide some type of pumping action. In some types of applications, such as circulating water in a hobby fish tank or blowing cooling air over electronic components, the movement of the pump components need not be linear. In such cases, a type of diaphragm that utilizes bending action is preferred. Examples of such applications are shown in FIGS. 1 to 5.

1 to 5 show air pumps, and FIG. 1 shows the air pump 10 assembled. The housing 12 is disc-shaped and cylindrical. Housing 12
An opening 14 provided at the top of the holder allows air to be taken in. The discharge air exits through a tubular connection 16 formed at the end of the generally rectangular discharge housing 18. The discharge housing 18 has an opening 20 (a fifth opening) provided in the earthen wall of the housing 12.
It receives air through [Fig]. A pair of side walls 21 and 22 extend upwardly from opposite sides of the opening 20 and parallel to each other. The internal dimensions of the discharge housing 18 are such that it can be slidably fitted onto the side walls 21, 22, to which it is joined in the finished product. A thin elastomeric disk 24 is shown in FIG. The elastomer disk 24 is circular and has slits in three areas. The slits 26 and 28 are Y-shaped, and the slit 30 is H-shaped. In the assembled air pump, the elastomer disc 24 is placed in the housing such that the H-shaped slits 30 are located below the opening 20 and the Y-shaped slits 26 and 28 are located below the opening 14. Placed on the inner wall of 12. In the assembled air pump, the elastomeric disk 24 is held in place by a retaining disk 32 shown in FIG. The retaining disk 32 is provided with two circular apertures 34 and 36 and two rectangular apertures 38, the rectangular apertures 38 being side by side and separated by a separator bar 40. This retaining disk 32 is positioned such that the opening 34 is below the slit 26 and the opening 36 is below the slit 28. With this positioning, the lateral slit of the H-shaped slit 30 is positioned below the center and rear pars 40.

Needless to say, the slits 26, 28, 30 act as valves. As the nidistomer material at the edge of the slit moves out of the face of the elastomeric disk, an opening is formed to allow air to pass through.

Slits 26 and 2 depending on the pressure increase in the housing
The opening 14 in the housing is positioned and small to prevent upward movement of the nidistomer material in the vicinity of 8. However, the openings 34 and 36 are large enough so that the elastomeric material in the vicinity of the legs, slits, and grooves 26 and 28 bends inward to form air passages from the opening 14 to the slits 26 and 28 and the openings 34 and 38. Air is allowed to pass into the housing through the. Thus, with such an arrangement, two check valves are provided which are arranged to allow air to be sucked into the air pump 10.

Because of the mono-quadrature pad 40 of the retaining disc 32, the elastomeric material on either side of the transverse slit of the H-shaped sleeve 30 is prevented from curving inwardly toward the interior of the pump. On the other hand, as shown in FIG.
The housing 12 is provided with an unobstructed upward curvature to allow air to flow out of the housing 12.

The method of assembling this air pump can be clearly seen from FIG. The housing 12 is hollow and open at the bottom, and has a force f4
2 is now accepted. The outer diameter of the cup 42 is designed to be slightly smaller than the inner diameter of the housing 12 by f#.

The upper edge of cup 42 abuts the periphery of a rigid retaining disk 320, which abuts elastomeric disk 24 and presses it against the inside of the earthen wall of housing 12.

Reference numeral 44 represents the transverse slit of the H-shaped sleeve) 30. At the top of the housing, the sidewall 22 is shown extending into the rectangular air discharge housing 18. Air is discharged from the tubular connection 16 of this housing 18.

The edge of the pimol electrostrictive element 46 is bonded to the inner surface of the bottom of the cup 42. In this embodiment, the bottom of the cup 42 is free to bend along with the electrostrictive element. As needed,
The electrostrictive element can be attached to the outside surface of the bottom of the cup, or the edge of the electrostrictive element can be attached to a non-flexible substrate and used as a wall of the pump housing as shown. Alternatively, the electrostrictive element may simply be suspended inside the cup.

Electrical connection to the conductive layer between the two electrostrictive elements is made via spade terminals 48. Electrical connection to the upper and lower conductive surfaces of the pimol electrostrictive element 46 is made via spade terminals 50. These terminals extend openings provided in the bottom wall of cup 42, and these openings are sealed with epoxy resin to prevent air leakage.

In this assembled state, the unit can be thought of as forming an air reservoir or forming part of an air flow path, which passes through the opening 14 in the housing and into the slit valve 26. and 28, opening 34
and 36 into the internal cavity 52 of this unit, thence further through an opening 38 in the retaining disc.
It can be thought of as extending through the H-shaped /J lube slit 30 through the opening 20 and through the discharge housing 18 and the tubular connection 16.

The air pump unit includes means for changing the volume of the air flow path by changing the dimensions of the air flow path. That is, the upper surface of the pimol electrostrictive element forms a part of the flow path. When an electric field is applied, the pimol electrostrictive element changes its shape to change the volume of the flow path, and more specifically, changes the volume of the storage tank 52. A unidirectional intermittent or alternating voltage is applied between terminals 48 and 50.

The dimensions of the pimol electrostrictive element 46 will then change with each electrical change cycle. When the volume of the storage tank decreases due to this change, air is forced out through the valve slit 30. At this time, valve slits 26 and 2
8 is closed. When the shape of the pymolar electrostrictive element 46 changes and the volume of the internal cavity 52 decreases, air is sucked in through the valve slits 26 and 28, but cannot enter or exit through the one-valve slit 30.

As a result, air flows from the outlet or tubular connection 16, and this air flow rate can be increased by increasing the frequency of voltage changes applied to terminals 48 and 50. The constraints on this increase in flow rate are the response capability of the valve and the compressibility of the air. Since the degree of dimensional change in the pimol electrostrictive element is a function of the magnitude of the applied voltage, the air flow rate can be controlled by varying the amplitude of the voltage change applied between terminals 48 and 50. .

FIG. 6 schematically shows a modified version of this pump. This pump is a double-acting pump in the sense that it has two flow paths, and these flow paths are connected to the pimol electrostrictive element 100.
There is one on each side. Pump body 102
is divided into an upper cavity 104 and a lower cavity 106 by a pimol electrostrictive element. In this embodiment, the pimol electrostrictive element is disk-shaped, and its periphery is embedded in the housing along the center line of the housing. It's included. The first fluid flow path is comprised of an inlet passageway 108 opening into the upper cavity 104 and an outlet passageway 110 exiting the upper cavity 104 . The other flow path is comprised of an inlet passage 112 opening into the lower cavity 106 and an outlet passage 114 receiving fluid from the lower cavity 106. These outlet passages 110 and 114 merge downstream to form a common outlet passage 116. Two check valves are installed in the husband's flow path. Check valve 1
20 allows fluid to flow from the inlet passageway 108 into the upper cavity 104, but prevents the reverse flow. The other check valve 122 allows fluid to flow from the upper cavity 104 to the outlet passageway 110. For the other flow path, the reverse valve 124 connects the inlet passageway 112 to the lower cavity 10.
6 and check valve 126 allows fluid to exit from lower cavity 106 to outlet passageway 114. The flow rate of the flow path that includes the lower cavity 106 as a part thereof is restricted by a restriction 130 . This aperture 13
0 is provided in the inlet passage 112 in this embodiment. The pump is activated by applying an intermittent or alternating voltage between two terminals 134. In this embodiment, a pair of weights 136 are joined to the central region of the pimol electrostrictive element to increase the mass, and these weights are arranged on both sides of the electrostrictive element. The mass of these weights is determined by the combination of the mass of the weights and the mass of the electrostrictive element when the two channels are filled with fluid and the pimol electrostrictive element is operated under load conditions. It is set so that it mechanically resonates with the frequency of changes in the applied voltage. Since the displacement amount of the pimol electrostrictive element can be precisely controlled by adjusting the magnitude of the applied voltage, a very precise amount of fluid can be pumped over a wide discharge amount range.

The term "pump" as used herein refers not only to a device capable of generating a continuous flow of fluid, but also to a device having the sole purpose of displacing fluid. Figures 7 to 9 illustrate examples of such applications.

The structure of FIG. 7 acts as an indicator. A cavity 202 is formed in the lower housing 200 . This cavity is charged with a fixed amount of fluid), and the amount of fluid changes when the dimensions of the sipimolar electrostrictive element 204 are changed by applying a voltage between terminals 206 and 208. If the fluid used for the indicator is a fluid whose volume changes as the temperature changes, this volume change can be compensated for by the temperature compensation mechanism 210. The temperature compensation mechanism contains a substance or material whose volume changes in a direction opposite to the change in indicator fluid. A bellows is provided on the lower surface of the temperature compensation mechanism 210, and the internal volume of the lower cavity 200 increases or decreases due to the movement of the bellows.

The lower cavity communicates with small diameter tube 212 . This tube 212
Although the drawing is shown enlarged to make it easier to understand, this tube generally has a capillary-like flow area and functions similarly to a capillary tube in a thermometer. A scale 214 is provided, and the height of the liquid column 216 in the capillary tube can be measured by comparing with this scale.

The degree of dimensional change of the pymolar electrostrictive element 204, and therefore the degree of change in the internal volume of the cavity 202, varies between the terminals 206 and 20.
It changes in proportion to the voltage applied between 8 and 8. cavity 2
When the volume of 02 increases, the height of liquid column 216 increases.

The electrostrictive element 204 is joined to the lower wall 220 of the lower housing 200. Applied voltage 100? Assume that the electrostrictive element 204 responds to voltage changes such that the wall thickness increases at a rate of 130 microns per root, and that the electrostrictive element is circular with a diameter of 30 microns at its top surface. Assuming that the diameter of the capillary flow area of the tube 2120 is 1 mm, the ratio of the electrostrictive element diameter to the capillary opening diameter is 30, and the area ratio is 900, which is jO1900 times. therefore,
A thickness change of 30 microns reduces the height of liquid column 216 by 2.7
cnL will change. The diameter and volume of the lower cavity can be relatively small. In particular, if the temperature compensation mechanism can be omitted, the device can be manufactured very cheaply. This is because the manufacturing technology of electrostrictive elements has advanced to such an extent that the cost thereof can be extremely reduced. Since the electrostrictive element has a capacitance and exhibits a very high electrical resistance, the power consumption necessary for displaying is minimal. Thus, an inexpensive and highly accurate voltage indicator (or indicator of a quantity if it is expressed in voltage)
is obtained. As in the case of a thermometer, the orientation K of this device is subject to certain constraints, but it is possible to orient it with a sufficient width, just as in the case of a thermometer.

FIG. 8 shows a variation of this voltmeter. In this embodiment, the pimol electrostrictive element 300 divides the chamber 302 into two reservoirs 30.
4 and 306. These two reservoirs are connected to each other by a small diameter capillary tube 308. The capillary tube extends downwardly from reservoir 306, then horizontally, then upwardly in section 310 to a point above chamber 302, then horizontally, and finally in section 3.
12 and returns to the storage tank 304.

The reservoir 304 and the section 312 of the capillary tube 308 contain the first fluid to the extent that the capillary section 312 is not fully filled. Section 310 between storage tank 306 and capillary tube 308 has section 3.
The second fluid is in the container to the extent that it does not fully fill the container. The zero point of scale 314 is positioned opposite to the top of the liquid column within capillary section 310 when electrostrictive element 300 is not excited. When a voltage of the polarity shown in FIG. Fluid flows upwardly within capillary section 310. When the physical path is determined, the height to which the liquid column 310 rises is determined by the magnitude of the voltage applied to the electrostrictive element. The scale 314 is graduated in units of voltage.

By reversing the polarity of the voltage applied to the electrostrictive element, the pymolar electrostrictive element bends upward, increasing the volume of the storage tank 306. The liquid column in the capillary section 310 will fall and the top of the liquid column will fall below the zero mark on the scale 314.

Thus, the device of FIG. 8 is a voltmeter 316 capable of reading zero potential. Reservoir 304 and capillary section 312
The liquid within is used to maintain a uniform pressure on the liquid column within the capillary section 310.

FIG. 9 shows an embodiment of an electrical switch using the present invention. This example combines two switches,
The switch 400 is of a two-pole type, a two-throw type, and a center-off type. Curved multi-molar electrostrictive element 402
divides the cavity 404 into two reservoirs 406 and 408. From respective storage tanks 406 and 408 riser pipes 4
10 and 412 extend upwardly. The liquid contained in each reservoir is electrically conductive, and by bending the electrostrictive element to reduce the volume of each reservoir, when the liquid is sufficiently raised, the conductive liquid will come into electrical contact with the fixed electrode. do. The electrode that cooperates with the riser pipe 410 is 414, and the electrode that cooperates with the riser pipe 412 is 416. terminal 41
8 and 420 constitute points of contact for the liquid in reservoirs 406 and 408, respectively.

In FIG. 9, a multi-mole electrostrictive element 402 is curved to form a storage tank 4.
The figure shows the volume of 06 reduced. The liquid in riser tube 410 has risen and is in contact with fixed contact 414 . When the polarity of the voltage applied to the electrostrictive element is reversed, the electrostrictive element bends in a direction that decreases the volume of the storage tank 408 and increases the volume of the storage tank 406. If you do that, the rising υ tube 41
The liquid within 0 drops and breaks contact with the fixed contact 414.

The liquid in riser tube 412 rises and contacts fixed contact 416 .

When the electrostrictive element is not excited, the electrostrictive element does not bend.

At this time, the two reservoirs have intermediate volumes and neither liquid reaches the fixed contact. However, if you add liquid to both reservoirs and reach just enough liquid to both stationary contacts to complete contact contact when the electrostrictive element is de-energized, this switch can be configured as a center-off type switch. It will no longer be.

Although specific embodiments of the invention have been described above, various modifications and changes can be made. That is, these embodiments are merely illustrative, and the present invention is not limited thereto.

[Brief explanation of drawings]

1 is a perspective view of an air pump according to a preferred embodiment of the present invention, FIG. 2 is a sectional view taken along line 2-2 of FIG. 1, and FIG. 3 is a valve disk of the air pump of FIG. 1. 4 is a perspective view of the holding disk of the air pump of FIG. 1, FIG. 5 is a perspective view of the housing of the air pump of FIG. 1, and FIG. 6 is a metering device according to another embodiment of the present invention. FIG. 7 is a schematic cross-sectional view of an indicator device according to an embodiment of the present invention; FIG. 8 is a schematic cross-sectional view of a zero center set voltmeter according to an embodiment of the present invention; FIG. 9 is a schematic cross-sectional view of a pump; 1 shows a two-pole, two-throw, voltage-responsive electric switch according to an embodiment of the present invention. 10...Air pump, 12...Housing, 14.
... Opening, 16... Tubular connection part, 18... Discharge housing, 20... Opening, 21.22... Side wall, 24
... Elastomer disk, 24, 26. 28, 30...
・Slit, 32... Holding disc, 34.36... Circular opening, 38... Rectangular opening, 40... Cell/mother blade, 42... Cup, 46... Pimol electrostrictive element , 48, 50... Sweet terminal, 52... Internal cavity (storage tank), 100... Pimol electrostrictive element, 102...
...Main body, 104...Upper cavity, 106...Lower cavity, 108...Inlet passage, 110...Outlet passage, 1
12... Inlet passage, 114... Outlet passage, 116.
・・Common exit passage, 120, 122゜124.126・
...Check valve, 130... Throttle, 134... Terminal, 1
36... weight! l), 200...lower housing,
202...Cavity, 204...794 molar electrostrictive element,
206° 208...Terminal, 210...Temperature compensation mechanism, 212...Small diameter tube, 214...Scale j5.216
...Liquid column, 220...Bottom wall, 300...Pimol electrostrictive element, 302...Chamber, 304.306...Storage tank, 308...Capillary tube, 310°312...Section, 3
16...Voltmeter, 400...Switch, 402...
・Multi-molar electrostrictive element, 404...Cavity, 406.4
08...Storage tank, 410,412...Rise pipe, 41
4,416...electrode (contact), 418°420...
terminal. Fig. 2 Fig. 3 Fig. 40 Fig. 5 Fig. 6 Decoy Pass

Claims (1)

[Scope of Claims] 1. A fluid reservoir capable of containing a fluid, and a pump member forming a movable part of the reservoir and movable to change the volume of the reservoir in the region of the movable part. a driving means in the form of an electrostrictive element capable of changing one dimension thereof when subjected to the action of an electric field; and means for moving the pump member as the dimension of the electrostrictive element changes. Fluid pump consisting of 2. The structure comprises a flow path communicating with the storage tank and a valve provided in the flow path, and the valve allows fluid to flow in one direction along the flow path (as the volume of the storage tank changes, the fluid passes through the valve). 2. The fluid pump according to claim 1, wherein the fluid pump only flows in the fluid pump. 3. A fluid pump according to claim 2, wherein said pump member comprises a diaphragm, and said drive means is connected to said diaphragm for moving said diaphragm. 4. The first aspect of the present invention comprises display means for storing a predetermined volume of liquid and displaying the extent to which the volume of the storage tank has been changed by the pump member by the position of a portion of the liquid in the flow path. Fluid pump as described in section. 5. The liquid is electrically conductive, and the display means includes an electrode disposed along the reservoir, so that when the volume change by the pump member reaches a predetermined level, the electrode 5. The fluid pump according to claim 4, wherein the fluid pump is adapted to be in contact with a liquid. 6. a second fluid reservoir, the pump member forming a movable part of both reservoirs, the pump member being movable to increase the volume of one reservoir while decreasing the volume of the other reservoir; A fluid ponder according to claim 1. 7. The fluid pump according to claim 6, wherein said drive means comprises said pump member. 8. An electrostrictive element of a type that changes dimensions in response to electrical excitation, a scale, and display means for displaying the entire magnitude of the dimensional change on the scale in response to the dimensional change. indicator consisting of. 9. The indicator according to claim 8, wherein the display means comprises a finite amount of liquid, and the shape of the liquid changes in response to changes in dimensions of the electrostrictive element. 10. The liquid is electrically conductive, and the scale is constituted by an electric contact, and the electric contact is positioned so as to come into contact with the liquid when the shape of the liquid changes to a predetermined degree. An indicator according to claim 9. 11. In a type of pump that flows or discharges multiple fluids along a flow path by operating a drive means to change the shape of the flow path, the drive means changes in size when an electric field is applied. What is claimed is: 1. A pump comprising: an electrostrictive element, one of which changes; and the pump is further provided with shape changing means for changing the shape of the flow path in accordance with a change in dimension of the electrostrictive element. 12. The pump according to claim 11, wherein said driving means comprises a multimolar electrostrictive element. 13. The pump according to claim 12, wherein said shape changing means comprises said multimolar electrostrictive element. 14. A patent claim comprising: a second channel through which a second fluid flows; and the shape changing means includes means for changing the shape of both channels in accordance with a change in dimension of the electrostrictive element. The pump according to item 11. 15. Two pairs of valves are provided, one pair of the valves are provided in each flow path, one of the valves of each pair is provided upstream of the shape changing means, and the other is provided upstream of the shape changing means. 15. A pump according to claim 14, wherein the pump is provided downstream of the means. 16. Alternatingly applying and releasing an electric field to the electrostrictive element at a frequency substantially close to the resonance frequency of the shape changing means when the flow path is filled with the fluid in the region of the shape changing means; Claim 1 comprising the means for
The chimp described in item 1. 17. A container containing two liquids, each liquid being sealed in each of the channels, and the shape of each liquid changing according to changes in the channels, 15. The pump according to claim 14, wherein the pump includes display means for displaying the degree of shape change of at least one of the liquids. 18. The respective liquids are electrically conductive, and the indicating means comprises at least two electrodes, each electrode being disposed at a selected point within a corresponding flow path. The pump according to item 17. 19. The fluid pump according to claim 1, further comprising means for changing the volume of the storage tank depending on the temperature. 20. The indicator according to claim 8, comprising means for changing the volume of the storage tank depending on the temperature.