JPH0727056A - Pump - Google Patents

Abstract

PURPOSE:To provide a pump capable of realizing shortening a time required for starting, high speediness of operation for switching a flow amount and flow direction, lightening weight, miniaturization, decreasing power consumption and further reducing a noise. CONSTITUTION:In the inside of a tubular equipment body 5, containing a movable wall 4 of constituting a flow path between the wall 4 and a fixed wall 5a in the inside of the equipment body 5 and a plurality of piezoelectric elements 3 (piezoelectric element 3a to 3d) arranged with a void (void 2a to 2d) provided between a back surface side of the movable wall 4 and an internal wall of the equipment body 5, a plurality of the piezoelectric elements 3 are individually connected to a control circuit through a socket and a signal wire. The control circuit, constituted of a control signal generating circuit for generating a pulsation signal applied to each of a plurality of the piezoelectric elements 3 and a piezoelectric element driving circuit for generating a pulsation power signal applied to the piezoelectric element 3, is a pump for forcing a fluid in a flow path 7 moved in one direction by extending/contracting the piezoelectric element 3 to form a progressive wave in the movable wall 4.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to pumps, and more particularly to
Aerospace field by downsizing and weight reduction of vacuum equipment,
Furthermore, the present invention relates to a technology effectively applied to the field of natural environment protection by reducing power consumption, noise, and vibration, and as an artificial organ for handling fluids in the medical field and the like.

[0002]

2. Description of the Related Art A conventional pump has a large outer shape and weight,
For example, vacuum pumps used in semiconductor manufacturing processes
It ranges from several kg to over 200 kg, and often accounts for 10% or more of the weight of semiconductor manufacturing equipment.

In particular, many oil-free vacuum pumps, which have become mainstream in the semiconductor manufacturing process in recent years, use blades that rotate at high speed, such as a turbo molecular pump.・ Power consumption is higher than conventional oil rotary pumps. Further, in these pumps, since the rotational kinetic energy of the rotating blades is large, there is a risk of causing a serious accident such as personal injury in the event of a failure.

[0004]

DISCLOSURE OF THE INVENTION As a conventional pump,
Taking a vacuum pump used in the semiconductor manufacturing process as an example, when an oil rotary pump or an oil diffusion pump is used, the carbon compound or other substances contained in the oil adhere to the product wafer, which causes the wafer Polluted,
It may be a factor that reduces productivity.

For this reason, pumps such as turbo molecular pumps and dry pumps that do not expose oil to the passage of the gas to be exhausted have come to be used. These vacuum pumps are high-speed rotation (turbo molecular pump, about 1
Exhaust is performed by forcibly pushing out gas molecules in one direction by a vane rotating at 0 ⁴ to 10 ⁵ revolutions / minute. However,
These pumps have some problems.

First, the rotary momentum of the rotary blade for pushing out gas molecules is large. For example, it takes several minutes to several tens of minutes even from a small-sized apparatus until the exhaust operation becomes possible from the stopped state. For this reason, it is not only necessary to wait at the same number of rotations as during operation, even when the exhaust operation is not being performed, but it is difficult to even change the exhaust speed and exhaust direction (reversal of suction and discharge). Is. Maintaining high speed rotation during standby increases power consumption. In addition, a dangerous accident may occur in which the blade breaks through the outer wall of the pump and damages the vacuum device.

Second, a large mechanical strength is required to support the blades rotating at high speed. External dimensions and weight are increased to obtain greater mechanical strength.

The third is noise generated by the motor for rotating the blades at high speed. Taking a large dry pump as an example, some of them emit noise exceeding 50 decibels (measured at a distance of 1 m from the pump), which not only worsens the working environment, but also significantly hinders communication between workers. It also causes an accident in the work around the pump.

An object of the present invention is to provide a pump capable of shortening the time required for start-up and speeding up the switching operation of the flow rate and the flow direction.

Another object of the present invention is to provide a pump which is safe and can realize weight reduction, size reduction, and power consumption reduction.

Still another object of the present invention is to provide a pump which produces low noise during operation.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0013]

Among the inventions disclosed in the present application, a brief description will be given to the outline of typical ones.
It is as follows.

According to the first aspect of the present invention, there is provided a flow passage through which a desired fluid flows, and traveling wave generating means arranged on the wall surface of the flow passage along the flow direction of the fluid to generate a traveling wave on the wall surface. In this pump, the cross-sectional area of the flow passage is temporally and spatially changed by the traveling wave of the wall surface to push out the fluid in the traveling wave direction.

According to a second aspect of the present invention, in the pump according to the first aspect, the traveling wave generating means includes a plurality of piezoelectric elements arranged along a fluid flow path, and a voltage applied to the piezoelectric elements. The control device has a function of generating a waveform and changing the velocity and amplitude of the traveling wave.

The invention according to claim 3 is the pump according to claim 1 or 2, wherein the flow path is formed between the fixed wall surface and the movable wall surface facing each other, and the traveling wave generating means is provided on the side of the movable wall surface. Are arranged.

Further, the invention according to claim 4 is based on claim 1,
In the pump described in the paragraph 2 or 3, the flow path is made of a tubular body, and traveling wave generating means is arranged around the tubular body along the flow direction of the fluid.

Further, the invention according to claim 5 is based on claim 1,
In the pump according to 2 or 3, the flow passage is formed in a gap between an inner circumference of the pipe body and an outer circumference of a core member inserted in the pipe body, and the flow passage travels around the pipe body in a fluid flow direction. The wave generating means is arranged.

The invention according to claim 6 is the same as that of claim 1,
It is a pump formed by bundling a plurality of pumps described in 2, 3, 4 or 5.

Further, the invention according to claim 7 is based on claim 1,
In the pump described in 2, 3, 4, 5 or 6, vibration applying means for applying vibration of a desired frequency and intensity to the flow passage is arranged at a desired position of the flow passage, and the traveling wave generating means is used. It cancels the sound generated from the flow path.

[0021] According to an eighth aspect of the invention, in the pump according to the first aspect, the traveling wave generating means is a plurality of piezoelectric elements arranged along a fluid flow path, and a voltage applied to the piezoelectric elements. The control device has a function of generating a waveform and changing the phase, velocity, amplitude, etc. of the traveling wave, and a resonance means for expanding the amplitude of the piezoelectric element.

Further, the invention according to claim 9 is based on claim 1,
In the pump described in 2, 3, 4, 5, 6, 7 or 8, another pump for sucking back pressure is connected to the discharge side of the flow path.

[0023]

In the pump of the present invention described above, a traveling wave in one direction is generated in the flow path by expansion / contraction of an actuator having no rotary motion portion, for example, a piezoelectric element, and the fluid is pushed out in one direction by this traveling wave. Configure the pump.

That is, a plurality of piezoelectric elements are arranged along the flow path, and driving is performed so that the individual piezoelectric elements operate in synchronization with each other to generate a traveling wave in one direction in the flow path.
By changing the drive timing, the flow rate and direction of the fluid are changed.

As a result, it is possible to shorten the time required for starting and to change the flow rate and direction of the fluid at high speed. Further, it can be operated regardless of the magnitude of the pressure on the primary side or the secondary side.

Furthermore, it is possible to construct a pump that has a small outer size and weight, is safe and consumes less power, and generates less noise.

[0027]

Embodiments of the present invention will now be described in detail with reference to the drawings.

Example 1 FIGS. 1 (a) and 1 (b) are
FIG. 2 is a schematic cross-sectional view showing an example of the configuration and action of a pump that is an embodiment of the present invention, and FIG. 2 is a schematic perspective view showing an example of its use.

In this embodiment, as an example, a case of functioning as a vacuum pump will be described.

The pump 1 is connected to the vacuum container 50 via a flange portion 6 having a through hole 6a. The vacuum container 50 is a process chamber used in a semiconductor device manufacturing process, for example.

As shown in FIG. 1 (a), this pump 1 has a through hole 6a formed inside a cylindrical casing 5 and between the fixed wall 5a inside the casing 5. Between the movable wall 4 forming the flow path 7 at a position, and the back side of the movable wall 4 and the inner wall of the housing 5 in the longitudinal direction of the flow path 7 with predetermined cavities 2 (cavities 2a to 2d). ) And a plurality of piezoelectric elements 3 (piezoelectric elements 3a to 3d) that are arranged.

The inner surfaces of the fixed wall 5a and the movable wall 4 forming the flow path 7 are highly cleaned by, for example, electrolytic polishing or the like to prevent the inside of the vacuum container 50 from being contaminated. In principle, the pump 1 of the present embodiment does not require a complicated rotating mechanism or the like, and oil for lubricating the rotating mechanism is unnecessary. Therefore, the inner circumference of the flow path 7 is once cleaned. For example,
There is no concern that contaminants, foreign substances, etc. will mix into the fluid from the pump 1 itself.

The plurality of piezoelectric elements 3 are individually connected to the control circuit 60 via the socket 1a and the signal line 1b. The vacuum container 50 is provided with a pressure sensor 1c that measures the degree of vacuum inside the vacuum container 50, and the measurement result is transmitted to the control circuit 60 via the signal line 1d.

The control circuit 60 is a control signal generation circuit 60 for generating a pulsation signal applied to each of the plurality of piezoelectric elements 3.
a and a piezoelectric element drive circuit 60b that generates a pulsating power signal that is actually applied to the piezoelectric element 3 in response to the pulsating signal.

Then, the control circuit 60 drives the pump 1 until the pressure in the vacuum container 50 reaches a desired pressure, stops the drive of the pump 1 when the desired pressure is reached, and after the stop, The control operation such as continuing to monitor the output of the pressure sensor 1c is performed.

An example of the operation of the pump 1 of this embodiment will be described below.

In the following description, each piezoelectric element 3
Is assumed to undergo degenerate deformation when a voltage is applied,
On the contrary, the essential operation is the same even when the voltage is extended when applied.

FIG. 6 is a diagram schematically showing the voltage applied to the piezoelectric element and the amount of deformation of the piezoelectric element, showing the static characteristics. It is known that the dynamic characteristics have hysteresis, but there is no essential difference.

FIG. 7 shows a voltage waveform applied to each piezoelectric element. FIG. 7A shows a voltage waveform when the volume of the flow path 7 is set to zero. On the other hand, FIG. 7B shows a voltage waveform during operation.

First, as illustrated in FIG. 7A, when no electric power is supplied to the plurality of piezoelectric elements 3, FIG.
As illustrated in (a), the movable wall 4 forming the flow path 7
In the natural state, that is, because the movable wall 4 and the fixed wall 5a are in close contact with each other by the piezoelectric element 3 in the natural state, that is, the flow rate of the gas discharged from the vacuum container 50 by the pump 1 becomes zero, The pump 1 acts as a valve in a fully closed state, and prevents gas from flowing into the vacuum container 50 from the outside.

On the other hand, as shown in FIG. 7B, the pulsating electric powers 3aw to 3dw with the shifted phases are supplied to the plurality of adjacent piezoelectric elements 3 (3a, 3b, 3c and 3d). Then, as shown in FIG. 1B, the piezoelectric element 3 (3a, 3b, 3c, and 3d) sequentially expands and contracts along the flow direction of the flow path 7 to deform the movable wall 4 into a wavy shape. Spaces 7a to 7c whose caliber changes in time in the axial direction of the flow path 7 are formed in the flow passage 7. By moving these spaces 7a to 7c with time, the inside of the vacuum container 50 The gas on the primary side is forcibly moved to the external secondary side, whereby the vacuum container 50 is evacuated.

FIG. 5 is a flow chart showing an example of the operation of the control circuit 60 and other components in the exhaust operation as described above.

First, the target degree of vacuum is set in advance (step S1). The actual vacuum degree obtained as the output of the pressure sensor 1c is compared with the target vacuum degree (steps S2 to S).
3). The phase velocity of the traveling wave applied to the piezoelectric element 3 is adjusted according to the difference between the actual vacuum degree and the target vacuum degree (S8-
S10). Specifically, the frequency of the voltage waveform applied to each piezoelectric element 3 is changed.

When the target degree of vacuum is reached, each piezoelectric element 3 is driven so that the volume of the flow path 7 becomes zero, that is, the state of FIG. 1 (a) (S4 to S7). Pressure sensor 1
The monitoring of the output of c continues.

In the above description, the operation of evacuating the inside of the vacuum container 50 has been described. However, by reversing the phase of the traveling wave applied to the piezoelectric element 3, the flow path 7 is instantaneously changed. It goes without saying that the operation of reversing the flow direction of the fluid in can be performed.

As described above, according to the pump 1 of the present embodiment, in principle, no complicated mechanism such as a member that rotates at high speed is required, shortening the required start-up time, and further, the flow rate of the fluid.
Fast direction change and switching operations are possible. Further, it can be operated regardless of the magnitude of the pressure on the primary side or the secondary side.

Further, the external dimensions and weight are small, the safety and the power consumption are low, and the noise is small. In addition, it is possible to reliably perform the closing operation of the flow path 7 without the need for a separate valve or the like.

Although not particularly shown, for example, the pump 1 may have a structure in which a plurality of flow paths 7 are arranged in parallel and bundled to obtain a large flow rate. In that case, the number of the pumps 1 to be bundled is adjusted according to the required flow rate.

(Embodiment 2) FIG. 3 is a schematic perspective view showing an example of the configuration of a pump 101 which is another embodiment of the present invention.

In the case of the second embodiment, the cylindrical casing 1 is used.
05 and the tubular movable wall 104 in which the flow path 107 is bored in the inner axis direction, a plurality of fan-shaped piezoelectric elements 10 are provided.
3 is arranged.

In other words, the plurality of piezoelectric elements 103 are arranged around the tubular movable wall 104 and in the axial direction to form a cavity 102, and a set of piezoelectric elements 103 at the same position in the axial direction (the present embodiment). In the case of the example, the pulsating powers with the same phase are applied to the four), and the pulsating powers with the phase shifts are applied to the plurality of sets of piezoelectric elements 103 located in the axial direction, whereby the flow paths 107 in the movable wall 104 are A traveling wave is formed on the plane of No. 2 and the fluid is forcibly moved in the flow path 107 in a desired direction according to the traveling wave.

FIG. 3 shows the moment when the flow path 107 is opened by the retracting operation of the pair of piezoelectric elements 103 at the ends, and the fluid is transferred by repeating the expanding and contracting operation of the flow path 107 in the axial direction. The operation is performed. When the piezoelectric element 103 is not energized, each piezoelectric element 103 is in an expanded state, and the flow path 107 in the movable wall 104 is in a closed state over the entire length.

(Embodiment 3) FIG. 4 is a schematic perspective view showing an example of the configuration of a pump 201 which is still another embodiment of the present invention.

In the case of the third embodiment, the core member 205a having high rigidity is inserted in the inner axial direction of the tubular movable wall 104 in the second embodiment, and the outer peripheral portion of the core member 205a and the movable wall 104 are inserted. A donut-shaped flow path 207 is formed between the inner peripheral portion and the inner peripheral portion.

(Fourth Embodiment) FIG. 8 is a schematic perspective view showing an example of the configuration of a pump 301 which is still another embodiment of the present invention.

In the case of the fourth embodiment, a vibrator 302 for applying a vibration to the housing 5 of the pump 1 is provided in a part of the pump 1 of the first embodiment, and a housing 5 from the vibrator 302. And a vibration control device 303 for controlling parameters such as frequency and amplitude of vibration applied to the.

Then, the vibration control device 303 cancels the vibration, that is, the sound, which is expected to be generated in the casing 5 of the pump 301 by the pulsating power applied to the piezoelectric element 3 in the pump 301 from the control circuit 60. The operation of applying vibration of frequency, amplitude and phase to the housing 5 via the vibrator 302 is performed.

As a result, it is possible to more reliably prevent the generation of noise during the operation of the pump 301.

(Embodiment 5) FIG. 9 is a schematic sectional view showing an example of the configuration of a pump 401 which is still another embodiment of the present invention.

In the case of the fifth embodiment, the piezoelectric element 3 and
The resonance member 402 is arranged between the movable walls 4 driven by the piezoelectric element 3, and the vibration amplitude of the piezoelectric element 3 is enlarged by the resonance operation of the resonance member 402 and is transmitted to the movable wall 4. This is different from the case of the first embodiment.

That is, the resonance member 402 has, for example, a comb-shaped vibration characteristic adjusting groove 402 on a part of its wall surface.
a is engraved. Then, by setting the width and depth of the vibration characteristic adjustment groove 402a, and further, the arrangement pitch and the like to desired values according to the vibration characteristic of the piezoelectric element 3, the expansion efficiency of the amplitude of the piezoelectric element 3 is maximized. I am trying to become.

As a result, the piezoelectric element 3 having the same characteristics
Even when using, there is an advantage that the amplitude of the traveling wave formed by the movable wall 4 becomes larger and the flow rate can be made larger.

Although the invention made by the present inventor has been specifically described based on the embodiment, the invention is not limited to the embodiment, and various modifications can be made without departing from the scope of the invention. Needless to say.

For example, in each of the above-described embodiments, the case where the vacuum pump is used as an example has been described.
It can be used as an artificial organ to be embedded in a living body because it can be downsized, and it can be used as a part of aerospace equipment, and even a refrigerator or air conditioner because it can be made lighter. It has a wide range of application fields such as use as a compressor, a heat dissipation device (radiator) that also serves as a compressor, a fuel injection device in an engine of an automobile, or the like.

[0065]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows.
It is as follows.

That is, according to the pump of the present invention, it is possible to obtain the effect that the time required for start-up can be shortened and the switching operation of the flow rate and the flow direction can be speeded up.

Further, according to the pump of the present invention,
It is possible to achieve the effect of achieving weight reduction, size reduction, and power consumption reduction.

Further, according to the pump of the present invention, it is possible to reliably reduce the noise during operation.

According to the pump of the present invention, the primary side,
The effect that it can be operated regardless of the magnitude of the pressure on the secondary side is obtained.

[Brief description of drawings]

1A and 1B are schematic cross-sectional views showing an example of the configuration and operation of a pump that is an embodiment of the present invention.

FIG. 2 is a schematic perspective view showing an example of its usage state.

FIG. 3 is a schematic perspective view showing an example of the configuration of a pump that is another embodiment of the present invention.

FIG. 4 is a schematic perspective view showing an example of the configuration of a pump that is still another embodiment of the present invention.

FIG. 5 is a flowchart showing an example of the operation of the pump according to the embodiment of the present invention.

FIG. 6 is a diagram schematically showing a voltage applied to a piezoelectric element and a deformation amount of the piezoelectric element.

7 (a) and 7 (b) are diagrams showing an example of the operation of the pump according to the embodiment of the present invention.

FIG. 8 is a schematic perspective view showing an example of the configuration of a pump that is still another embodiment of the present invention.

FIG. 9 is a schematic cross-sectional view showing an example of the configuration of a pump that is still another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pump 1a Socket 1b Signal line 1c Pressure sensor 1d Signal line 2 (2a-2d) Cavity 3 (3a-3d) Piezoelectric element 3aw-3dw Pulsating electric power 4 Movable wall 5 Housing 5a Fixed wall 6 Flange part 6a Through hole 7 Flow Paths 7a to 7c Space 50 Vacuum container 60 Control circuit 60a Control signal generation circuit 60b Piezoelectric element drive circuit 101 Pump 102 Cavity 103 Piezoelectric element 104 Movable wall 105 Housing 107 Flow path 201 Pump 205a Core member 207 Flow path 301 Pump 302 Transducer 303 Vibration Control Device 401 Pump 402 Resonant Member (Resonance Means) 402a Vibration Characteristic Adjustment Groove

Claims (9)

[Claims] 1. A wall surface comprising a flow path through which a desired fluid flows, and a traveling wave generating means disposed on the wall surface of the flow path along the flow direction of the fluid to generate a traveling wave on the wall surface. The pump for moving the fluid in the advancing direction of the traveling wave by changing the cross-sectional area of the flow path temporally and spatially by the traveling wave. 2. The traveling wave generating means generates a plurality of piezoelectric elements arranged along the flow path of the fluid and a voltage waveform to be applied to the piezoelectric elements, the phase, velocity and The pump according to claim 1, comprising a control device having a function of changing the amplitude and the like. 3. The flow path is formed between a fixed wall surface and a movable wall surface facing each other, and the traveling wave generating means is arranged on the side of the movable wall surface. Pump described. 4. The flow path is formed of a tubular body, and the traveling wave generating means is arranged around the tubular body along the flow direction of the fluid. Three
Pump described. 5. The flow path is formed in a gap between an inner circumference of a pipe body and an outer circumference of a core member inserted in the pipe body, and the flow passage is formed around the pipe body along a flow direction of the fluid. 4. The pump according to claim 1, wherein the traveling wave generating means is arranged. 6. A pump comprising a plurality of the pumps according to claim 1, 2, 3, 4 or 5 bundled together. 7. A vibration applying means for applying a vibration having a desired frequency and intensity to the flow passage is arranged at a desired position of the flow passage, and a sound generated from the flow passage by the traveling wave generating means is provided. 2. The method according to claim 1, wherein
The pump according to 2, 3, 4, 5 or 6. 8. The traveling wave generating means generates a plurality of piezoelectric elements arranged along the flow path of the fluid and a voltage waveform applied to the piezoelectric elements, and determines the phase, velocity and The pump according to claim 1, comprising a control device having a function of changing the amplitude and the like, and a resonance means for expanding the amplitude of the piezoelectric element. 9. The pump of claim 1, 2, 3, 4, 5, 6, 7 or 8, wherein another pump for sucking back pressure is connected to the discharge side of the flow path. Pump.