Patent Application
20240026871
The present technology relates to a technology of a diaphragm pump and the like.
For small and thin pumps, a diaphragm pump using a diaphragm is put into practical use (see, e.g., Patent Literature 1 below). In the diaphragm pump, when a volumetric capacity of a pump chamber increases by bending deformation of a diaphragm, a fluid is taken in the pump chamber. Meanwhile, when the volumetric capacity of the pump chamber decreases, the fluid is discharged from the pump chamber.
There is a need for a technology capable of improving driving efficiency of a diaphragm pump.
In view of the circumstances as described above, it is an object of the present technology to provide a technology or the like capable of improving driving efficiency of a diaphragm pump.
A diaphragm pump according to the present technology includes a first diaphragm, a second diaphragm, and an adjustment portion.
The first diaphragm includes a first member including a first elastic portion, and a first drive unit that elastically deforms the first elastic portion by drive of the first drive unit.
The second diaphragm includes a second member that includes a second elastic portion and forms a space with the first member, a fluid flowing in the space, and a second drive unit that elastically deforms the second elastic portion.
The adjustment portion is provided to at least one of the first diaphragm or the second diaphragm and is for adjusting a resonant frequency of the at least one of the first diaphragm or the second diaphragm.
As described above, the present technology includes the adjustment portion, so that the resonant frequencies of the first diaphragm and the second diaphragm can be equalized as much as possible. This makes it possible to improve driving efficiency of the diaphragm pump.
An electronic apparatus according to the present technology includes a diaphragm pump.
The diaphragm pump includes a first diaphragm, a second diaphragm, and an adjustment portion.
The first diaphragm includes a first member including a first elastic portion, and a first drive unit that elastically deforms the first elastic portion by drive of the first drive unit.
The second diaphragm includes a second member that includes a second elastic portion and forms a space with the first member, a fluid flowing in the space, and a second drive unit that elastically deforms the second elastic portion by drive of the second drive unit.
The adjustment portion is provided to at least one of the first diaphragm or the second diaphragm and is for adjusting a resonant frequency of the at least one of the first diaphragm or the second diaphragm.
A manufacturing apparatus for a diaphragm pump according to the present technology includes an adjustment portion formation unit.
The adjustment portion formation unit forms an adjustment portion for adjusting a resonant frequency of at least one of a first diaphragm or a second diaphragm on at least one of the first diaphragm or the second diaphragm, the first diaphragm including a first member including a first elastic portion, and a first drive unit that elastically deforms the first elastic portion by drive of the first drive unit, the second diaphragm including a second member that includes a second elastic portion and forms a space with the first member, a fluid flowing in the space, and a second drive unit that elastically deforms the second elastic portion by drive of the second drive unit.
A manufacturing method for a diaphragm according to the present technology includes:
Hereinafter, embodiments according to the present technology will be described with reference to the drawings.
<Overall Configuration and Configuration of Each Unit>
As shown in those figures, the diaphragm pump 10 includes a first diaphragm 1a and a second diaphragm 1b that are disposed to face each other. Additionally, the diaphragm pump 10 further includes an adjustment portion 11 for adjusting a resonant frequency (eigenvalue) of the first diaphragm 1a and the second diaphragm 1b.
The diaphragm pump 10 is configured to be capable of taking in and discharging a fluid by drive of the first diaphragm 1a and the second diaphragm 1b. Note that a fluid used in the diaphragm pump 10 may be gas such as air or liquid such as water.
The first diaphragm 1a includes a flat plate-like first plate member 2a (first member) and a first piezoelectric element 3a (first drive unit) that bends and deforms the first plate member 2a (first elastic portion 5a) vertically by the drive thereof. The second diaphragm 1b includes a flat plate-like second plate member 2b (second member) that forms a space 13 for holding a fluid with the first plate member 2a, and a second piezoelectric element 3b (second drive unit) that bends and deforms the second plate member 2b (second elastic portion vertically by the drive thereof.
The first piezoelectric element 3a and the second piezoelectric element 3b are each formed of a piezoelectric material such as PZT. The first piezoelectric element 3a is provided in the vicinity of the center of the first plate member 2a in the upper portion of the first plate member 2a. The second piezoelectric element 3b is provided in the vicinity of the center of the second plate member 2b in the lower portion of the second plate member 2b. Note that each of the first piezoelectric element 3a and the second piezoelectric element 3b may have a laminated structure of two or more layers.
In this example, the first piezoelectric element 3a and the second piezoelectric element 3b have a circular shape in plan view, but may be configured to have a shape such as an oval shape or a polygonal shape in plan view or may be configured to have an annular shape.
The first plate member 2a of the first diaphragm 1a and the second plate member 2b of the second diaphragm 1b are formed of various materials such as resin and metal. In the example shown in
The first plate member 2a includes a first fixing portion 4a located on the outer circumferential side, a first elastic portion 5a provided on the lower side of the first piezoelectric element 3a at a position corresponding to the first piezoelectric element 3a, and a first spring portion 6a interposed between the first fixing portion 4a and the first elastic portion 5a.
Similarly, the second plate member 2b includes a second fixing portion 4b located on the outer circumferential side, a second elastic portion 5b provided on the upper side of the second piezoelectric element 3b at a position corresponding to the second piezoelectric element 3b, and a first spring portion 6a interposed between the second fixing portion 4b and the first elastic portion 5a.
The first fixing portion 4a and the second fixing portion 4b are fixed ends, and when the diaphragm pump 10 is attached to another device such as an electronic apparatus, a prat or all of the fixed ends are fixed at the attachment positions thereof as necessary.
Note that examples of an electronic apparatus on which the diaphragm pump 10 is mounted include a personal computer (PC), a mobile phone (including a smartphone), a wearable device, and a haptic device, but the type of the electronic apparatus is not particularly limited (e.g., the diaphragm pump 10 is used as a cooling device).
The first elastic portion 5a is elastically deformable and is vertically bendable by the first piezoelectric element 3a. Similarly, the second elastic portion 5b is elastically deformable and is vertically bendable by the second piezoelectric element 3b. In the example shown in the figure, the first elastic portion 5a and the second elastic portion 5b are circular in plan view (because the first piezoelectric element 3a and the second piezoelectric element 3b are circular), but may have a polygonal shape or the like, and the shape thereof is not particularly limited.
The first spring portion 6a is capable of promoting elastic deformation of the first elastic portion 5a. Similarly, the second spring portion 6b is capable of promoting elastic deformation of the second elastic portion 5b.
The first spring portion 6a is formed by a first groove 7a provided along the circumferential direction, on the upper side of the first plate member 2a and in the circumference of the first elastic portion 5a. Similarly, the second spring portion 6b is formed by a second groove 7b provided along the circumferential direction, on the lower side of the second plate member 2b and in the circumference of the second elastic portion 5b. Note that, in the example shown in
Further, in the example shown in
Note that, in this embodiment, the first plate member 2a itself is formed of the same material, and thus the first fixing portion 4a, the first elastic portion 5a, and the first spring portion 6a are formed of the same material in this embodiment. Meanwhile, the first fixing portion 4a, the first elastic portion 5a, and the first spring portion 6a may be formed of different materials.
For example, the first fixing portion 4a is formed of a material having a higher rigidity than that of the first elastic portion 5a and the first spring portion 6a. Meanwhile, the first elastic portion 5a may be formed of a material having a higher elastic modulus than that of the first fixing portion 4a, and the first spring portion 6a may be formed of a material having a still higher elastic modulus than that of the first elastic portion 5a. This also applies to the second fixing portion 4b, the second elastic portion 5b, and the second spring portion 6b.
The diaphragm pump 10 includes a casing 12 that includes the space 13 capable of holding a fluid therein. The casing 12 is constituted by the first plate member 2a of the first diaphragm 1a, the second plate member 2b of the second diaphragm 1b, and a cylindrical body 14 interposed between the first plate member 2a and the second plate member 2b. Note that the casing 12 may be provided with a lid for covering the first diaphragm 1a and the second diaphragm 1b, though not shown in the figure.
The cylindrical body 14 includes an inlet 15 for causing a fluid to flow in the space 13 from the outside, and an outlet 16 for causing the fluid to flow out from the space 13 to the outside. The inlet 15 and the outlet 16 are each provided so as to pass through the cylindrical body 14 in the horizontal direction. Further, the inlet 15 and the outlet 16 are provided at the positions opposite to each other with the space 13 being sandwiched therebetween.
In the cylindrical body 14, a first check valve 17 is provided at a position corresponding to the inlet 15, whereas a second check valve 18 is provided at a position corresponding to the outlet 16. The first check valve 17 is provided on the inner circumferential side of the cylindrical body 14, whereas the second check valve 18 is provided on the outer circumferential side of the cylindrical body 14.
Note that, in this embodiment, the inlet 15 and the outlet 16 are provided in a direction perpendicular to the vibration direction of the diaphragm 1, but the inlet 15 and the outlet 16 may be provided in a direction parallel to the vibration direction of the diaphragm 1. In this case, for example, the inlet 15 and the outlet 16 are provided so as to vertically pass through the first diaphragm 1a (or the second diaphragm 1b), for example, at the first fixing portion 4a of the first diaphragm 1a (or the second fixing portion 4b of the second diaphragm 1b).
In this embodiment, the adjustment portion 11 is provided to only one of the first piezoelectric element 3a and the second piezoelectric element 3b. Note that the adjustment portion 11 may be provided to both the first piezoelectric element 3a and the second piezoelectric element 3b.
The adjustment portion 11 is capable of adjusting a resonant frequency (eigenvalue) of the first diaphragm 1a and the second diaphragm 1b. In this embodiment, the adjustment portion 11 is used to equalize the resonant frequencies of the first diaphragm 1a and the second diaphragm 1b as much as possible, thus improving the driving efficiency of the diaphragm pump 10.
The adjustment portion 11 is formed of, for example, a potting material by potting processing. Examples of the potting material include various resins such as a urethane resin, an epoxy resin, and a silicon resin, and various metals such as solder, but the potting material is not limited thereto. Note that the adjustment portion 11 may be formed by other methods such as coating, screen printing, and sputtering. In this case as well, the adjustment portion 11 is formed of various resins, various metals, and the like.
In the example shown in the figure, the adjustment portion 11 is provided so as to cover the entire region of the first piezoelectric element 3a on the first piezoelectric element 3a. Meanwhile, the adjustment portion 11 may be provided so as to cover a part of the region of the first piezoelectric element 3a on the first piezoelectric element 3a or may be provided so as to be separated into a plurality of parts in a scattered manner.
Next, a typical operation of the diaphragm pump 10 will be described.
As shown in
When the first elastic portion 5a bens and deforms toward the upper side, and the second elastic portion 5b bens and deforms toward the lower side, the space 13 inside the casing 12 expands, and the pressure inside the space 13 is made smaller than that of the outside. Thus, a fluid flows in the space 13 from the outside via the inlet 15. Note that, at that time, the first check valve 17 provided to the inlet 15 is opened due to a difference in pressure between the outside and the inside of the space 13, whereas the second check valve 18 provided to the outlet 16 is closed due to the difference in pressure between the outside and the inside of the space 13.
When the input voltages with the opposite phases (sine waves and the like) are applied to the first piezoelectric element 3a and the second piezoelectric element 3b continuously from the state shown in
When the first elastic portion 5a bens and deforms toward the lower side, and the second elastic portion 5b bens and deforms toward the upper side, the space 13 inside the casing 12 contracts, and the pressure inside the space 13 is made larger than that of the outside. Thus, the fluid flows out from the inside of the space 13 to the outside via the outlet 16. Note that, at that time, the first check valve 17 provided to the inlet 15 is closed due to the difference in pressure between the outside and the inside of the space 13, whereas the second check valve 18 provided to the outlet 16 is opened due to the difference in pressure between the outside and the inside of the space 13.
<Basic Concept of Present Technology>
Next, a basic concept of the present technology will be described.
Further, the first comparative example is a theoretically ideal diaphragm pump 21, in which a resonant frequency of a first diaphragm 1a and a resonant frequency of a second diaphragm 1b completely coincide with each other. For example, the size (X and Y directions) and a thickness t (Z direction) of a first piezoelectric element 3a and the size and a thickness t of a second piezoelectric element 3b completely coincide with each other, and the size and thickness of a first plate member 2a and the size and thickness of a second plate member 2b completely coincide with each other, so that resonant frequencies of the first diaphragm 1a and the second diaphragm 1b completely coincide with each other.
In such a diaphragm pump 21 according to the first comparative example, it is assumed that input voltages with the opposite phases (sine waves and the like) are applied to the first piezoelectric element 3a and the second piezoelectric element 3b. In this case, at the output, the first diaphragm 1a (first elastic portion 5a) and the second diaphragm 1b (second elastic portion 5b) have vibrations with ideally opposite phases due to the bending deformation thereof, and the time at which the amplitude has the maximum point is the same. This makes it possible to drive the diaphragm pump 21 with the maximum efficiency.
Here, since it is actually impossible to manufacture the first diaphragm 1a and the second diaphragm 1b that are completely the same, generally, the resonant frequency of the first diaphragm 1a and the resonant frequency of the second diaphragm 1b do not coincide with each other.
For example, due to the variations in manufacturing, a first piezoelectric element 3a and a second piezoelectric element 3b may be different in the size (X and Y directions) and thickness (Z direction) thereof. Further, a first plate member 2a and a second plate member 2b may be different in the size and thickness thereof. For example, due to such variations, the resonant frequency of the first diaphragm 1a and the resonant frequency of the second diaphragm 1b may differ.
Note that
In such a diaphragm pump 22 according to the second comparative example, it is assumed that input voltages with opposite phases (sine waves and the like) are applied to the first piezoelectric element 3a and the second piezoelectric element 3b. In this case, at the output, the first diaphragm 1a (first elastic portion 5a) and the second diaphragm 1b (second elastic portion 5b) have the vibration phases shifted due to the bending deformation thereof from the opposite phases, and the time at which the amplitude has the maximum point differs. This makes it difficult to efficiently drive the diaphragm pump 10.
For that reason, in this embodiment, the adjustment portion 11 for adjusting a resonant frequency is provided to one of (or may be both of) the first diaphragm 1a and the second diaphragm 1b. Thus, the resonant frequency of the first diaphragm 1a and the resonant frequency of the second diaphragm 1b are equalized as much as possible, and thus the driving efficiency of the diaphragm pump 10 is improved.
<Manufacturing Apparatus 30 and Manufacturing Method>
Next, a manufacturing apparatus 30 and a manufacturing method for the diaphragm pump 10 will be described.
As shown in
The diaphragm generation unit 31 forms a piezoelectric element 3 at a position, which corresponds to an elastic portion of a plate member 2 (e.g., bonds and fixes the piezoelectric element 3 to the elastic portion 5), so that a diaphragm 1 is generated (see the top and second top diagrams of
Note that the diaphragm generation unit 31 may form a groove 7 in the plate member 2 and form a spring portion 6 in the plate member 2. Either one of the step of forming the spring portion 6 and the step of forming the piezoelectric element 3 may be performed first.
The first measurement unit 32 applies an input voltage (sine waves and the like) to the piezoelectric element 3 of the diaphragm 1 transferred from the diaphragm generation unit 31 and vibrates the diaphragm 1. The first measurement unit 32 then measures frequency characteristics (resonant frequency) and amplitude characteristics of the diaphragm 1 (see the third top diagram of
Further, the first measurement unit 32 outputs information of the measured frequency characteristics and amplitude characteristics to the control apparatus 37. The first measurement unit 32 then transfers the diaphragm 1, for which the measurement has been completed, to the pairing unit 33 in sequence.
The first measurement unit 32 is constituted by, for example, a Doppler displacement meter, but may be constituted by any apparatus as long as it is an apparatus capable of measuring frequency characteristics and amplitude characteristics of the diaphragm 1.
The pairing unit 33 is capable of storing a plurality of diaphragms 1 transferred from the first measurement unit 32 (e.g., approximately 10 to 100 pieces: at least three pieces or more). Such a pairing unit 33 pairs two diaphragms 1 having close frequency characteristics (resonant frequency) and amplitude characteristics from the plurality of diaphragms 1 stored, and selects them as a first diaphragm 1a and a second diaphragm 1b (see the second diagram from the bottom of
Note that the pairing unit 33 performs such a paring operation in response to a command from the control apparatus 37, which stores the frequency characteristics and amplitude characteristics of each diaphragm 1. Further, the pairing unit 33 transfers the two paired diaphragms 1 to the assembly unit 34 in sequence.
The assembly unit 34 fixes one diaphragm 1 of the two diaphragms 1 transferred from the pairing unit 33 to the upper surface of a cylindrical body 14, and fixes the other diaphragm 1 to the lower surface of the cylindrical body 14, thus assembling a diaphragm pump 10 (see the bottom diagram of
The second measurement unit 35 applies an input voltage (sine waves and the like) to the first piezoelectric element 3a and the second piezoelectric element 3b of the diaphragm pump 10 transferred from the diaphragm generation unit 31, and vibrates the first diaphragm 1a and the second diaphragm 1b. The first measurement unit 32 then measures frequency characteristics (resonant frequency) and amplitude characteristics for each of the first diaphragm 1a and the second diaphragm 1b (see the top diagram of
Further, the second measurement unit 35 outputs information of the measured frequency characteristics and amplitude characteristics to the control apparatus 37. The second measurement unit 35 then transfers the diaphragm pump 10, for which the measurement has been completed, to the adjustment portion formation unit 36 in sequence.
The second measurement unit 35 is constituted by, for example, a Doppler displacement meter, but may be constituted by any apparatus as long as it is an apparatus capable of measuring frequency characteristics and amplitude characteristics of the diaphragm 1.
The adjustment portion formation unit 36 forms an adjustment portion 11 on one of the first diaphragm 1a and the second diaphragm 1b (first piezoelectric element 3a and second piezoelectric element 3b) of the diaphragm pump 10 transferred from the second measurement unit 35 in response to a command from the control apparatus 37. Description on one of the first diaphragm 1a and the second diaphragm 1b (first piezoelectric element 3a and second piezoelectric element 3b), to which the adjustment portion 11 is to be provided, and the amount (thickness) of the adjustment portion 11 to be provided will be given later in detail.
The control apparatus 37 collectively controls the entire manufacturing apparatus 30. The control apparatus 37 includes a controller and storage. The controller is constituted by, for example, a central processing unit (CPU) or the like. The storage includes a volatile memory used as an operation area of the controller and a nonvolatile memory that stores various types of data, programs, and the like. The control apparatus 37 may be constituted by a general-purpose apparatus such as a PC or may be constituted by a dedicated apparatus for the manufacturing apparatus 30.
The control apparatus 37 determines which diaphragms 1 have close frequency characteristics (resonant frequency) and amplitude characteristics on the basis of the frequency characteristics (resonant frequency) and amplitude characteristics of each diaphragm 1, which are acquired from the first measurement unit 32. The control apparatus 37 then outputs a command to the pairing unit 33 and causes the pairing unit 33 to pair two diaphragms 1.
Further, the control apparatus 37 determines how much of the adjustment portions 11 is to be formed on which one of the first diaphragm 1a and the second diaphragm 1b (first piezoelectric element 3a and second piezoelectric element 3b) on the basis of the frequency characteristics (resonant frequency) and amplitude characteristics of the first diaphragm 1a and the second diaphragm 1b, which are acquired from the second measurement unit 35. The controller then outputs a command to the adjustment portion formation unit 36 and causes the adjustment portion formation unit 36 to form the adjustment portion 11.
<How Much of Adjustment Portion 11 Is To Be Formed On Which One of Diaphragms 1>
Next, description will be given on how much of the adjustment portion 11 is to be formed on which one of the first diaphragm 1a and the second diaphragm 1b.
First, there are two patterns for a method of matching the resonant frequency of the first diaphragm 1a and the resonant frequency of the second diaphragm 1b.
Referring to the upper part of
In the case of the first pattern, the adjustment portion 11 is formed on a piezoelectric element 3 of the diaphragm 1 on the low frequency side. Further, in order to increase the resonant frequency of the diaphragm 1, a material having a higher elastic modulus than that of the material of the piezoelectric element is used as the material used for the adjustment portion 11. Note that the simulation result reveals that, if the adjustment portion 11 is formed of a material having a physical property value equivalent to that of solder, the resonant frequency can be increased efficiently and easily.
Referring to the lower part of
In the case of the second pattern, the adjustment portion 11 is formed on a piezoelectric element 3 of the diaphragm 1 on the high frequency side. Further, in order to decrease the resonant frequency of the diaphragm 1, a material having a lower elastic modulus and a higher specific gravity than those of the material of the piezoelectric element is used as the material for the adjustment portion 11.
Next, the amount (thickness) of the adjustment portion 11 will be described. First, the amount of the adjustment portion 11 is changed in advance, and when the adjustment portion 11 with that amount is formed, the degree of change in the resonant frequency of the diaphragm 1 is measured. Thus, a relationship between the amount of the adjustment portion 11 and a change rate of the resonant frequency of the diaphragm 1 is aggregated statistically.
The difference between the resonant frequency of the first diaphragm 1a and the resonant frequency of the second diaphragm 1b is then calculated, and the amount of the adjustment portion 11 for compensating for the difference is determined on the basis of the relationship. Note that, as the difference between the resonant frequency of the first diaphragm 1a and the resonant frequency of the second diaphragm 1b becomes larger, the amount (thickness) of the adjustment portion 11 is increased.
The processing of the control apparatus 37 will be specifically described with an example. First, the first pattern will be described. The control apparatus 37 stores in advance the relationship between the amount (thickness) of the adjustment portion 11 and the change rate of the resonant frequency of the diaphragm 1. The control apparatus 37 determines which diaphragm 1 has a smaller resonant frequency when acquiring the resonant frequency (frequency characteristics) of the first diaphragm 1a and the resonant frequency (frequency characteristics) of the second diaphragm 1b from the second measurement unit 35. The control apparatus 37 then determines the diaphragm 1 having a smaller resonant frequency as a diaphragm 1 on which the adjustment portion 11 is to be formed.
Next, the control apparatus 37 calculates the difference between the resonant frequency of the first diaphragm 1a and the resonant frequency of the second diaphragm 1b. The control apparatus 37 then determines the amount (thickness) of the adjustment portion 11 on the basis of the relationship between the amount (thickness) of the adjustment portion 11 and the change rate of the resonant frequency, and the difference in the resonant frequency. The control apparatus 37 then notifies the adjustment portion formation unit 36 of information indicating a diaphragm 1, on which the adjustment portion 11 is to be formed, and information indicating the amount of the adjustment portion 11, and causes the adjustment portion formation unit 16 to form the adjustment portion 11. Note that the adjustment portion 11 at that time has a higher elastic modulus than that of the piezoelectric element.
Next, the second pattern will be described. The control apparatus 37 stores in advance the relationship between the amount (thickness) of the adjustment portion 11 and the change rate of the resonant frequency of the diaphragm 1. The control apparatus 37 determines which diaphragm 1 has a larger resonant frequency when acquiring the resonant frequency (frequency characteristics) of the first diaphragm 1a and the resonant frequency (frequency characteristics) of the second diaphragm 1b from the second measurement unit 35. The control apparatus 37 then determines the diaphragm 1 having a larger resonant frequency as a diaphragm 1 on which the adjustment portion 11 is to be formed.
Next, the control apparatus 37 calculates the difference between the resonant frequency of the first diaphragm 1a and the resonant frequency of the second diaphragm 1b. The control apparatus 37 then determines the amount (thickness) of the adjustment portion 11 on the basis of the relationship between the amount (thickness) of the adjustment portion 11 and the change rate of the resonant frequency, and the difference in the resonant frequency. The control apparatus 37 then notifies the adjustment portion formation unit 36 of information indicating a diaphragm 1, on which the adjustment portion 11 is to be formed, and information indicating the amount of the adjustment portion 11, and causes the adjustment portion formation unit 16 to form the adjustment portion 11. Note that the adjustment portion 11 at that time has a lower elastic modulus and a higher specific gravity than those of the piezoelectric element.
<Operation Etc.>
As described above, in this embodiment, the adjustment portion 11 is formed on the first diaphragm 1a or the second diaphragm 1b, so that the resonant frequency of the first diaphragm 1a and the resonant frequency of the second diaphragm 1b can be equalized as much as possible. This makes it possible to suitably set the vibration phases of the first diaphragm 1a and the second diaphragm 1b to be the opposite phases and to set the same time for the maximum point of the amplitude (e.g., like an ideal diaphragm pump as shown in
Note that the following experimental result is obtained: when the difference in vibration frequency between the first diaphragm 1a and the second diaphragm 1b before forming the adjustment portion 11 was 600 Hz (the vibration frequency was approximately 20 kHz), and when an adjustment portion 11 having the size of approximately 0.1 mm was formed on a piezoelectric element of one of the diaphragms 1, the difference in vibration frequency was almost zero.
Further, in this embodiment, two diaphragms 1 having close resonant frequencies are selected as the first diaphragm 1a and the second diaphragm 1b from the plurality of diaphragms 1. This needs less amount of the adjustment portion 11 and makes it possible to efficiently match the resonant frequencies of the first diaphragm 1a and the second diaphragm 1b with each other.
Further, in this embodiment, if the resonant frequency of one of the diaphragms 1 is increased to match the resonant frequencies of the first diaphragm 1a and the second diaphragm 1b with each other, a material having a higher elastic modulus than that of the piezoelectric element 3 is used as the material for the adjustment portion 11. This makes it possible to suitably increase the resonant frequency of the diaphragm 1.
Further, in this embodiment, if the resonant frequency of one of the diaphragms 1 is decreased to match the resonant frequencies of the first diaphragm 1a and the second diaphragm 1b with each other, a material having a lower elastic modulus and a higher specific gravity than those of the piezoelectric element 3 is used as the material for the adjustment portion 11. This makes it possible to suitably decrease the resonant frequency of the diaphragm 1.
Further, in this embodiment, a resonant frequency (frequency characteristics) of each of the first diaphragm 1a and the second diaphragm 1b (after assembly) is measured, and on the basis of the resonant frequency, the amount (thickness) of the adjustment portion 11 is determined. This makes it possible to suitably match the resonant frequency of the first diaphragm 1a and the resonant frequency of the second diaphragm 1b with each other.
In particular, in this embodiment, the amount (thickness) of the adjustment portion 11 is determined on the basis of the difference in resonant frequency between the first diaphragm 1a and the second diaphragm 1b and the relationship between the amount (thickness) of the adjustment portion 11 and the change rate of the resonant frequency of the diaphragm 1. This makes it possible to more suitably match the resonant frequency of the first diaphragm 1a and the resonant frequency of the second diaphragm 1b with each other.
Next, a second embodiment of the present technology will be described. Here, according to the adjustment portion 11 described above, the resonant frequency of the first diaphragm 1a and the resonant frequency of the second diaphragm 1b can be equalized as much as possible, and a phase shift from the opposite phase in the vibrations of the first diaphragm 1a and the second diaphragm 1b is reduced, but the phase shift may remain.
In this regard, in the second embodiment, the phase control of an input voltage (input signal: sine waves and the like) is performed on the basis of a phase difference between the opposite phases of the vibrations of the first diaphragm 1a and the second diaphragm 1b. This causes the vibrations of the first diaphragm 1a and the second diaphragm 1b to be approximated to have the opposite phases without limit.
<Basic Concept>
First, a basic concept of the second embodiment will be described with comparative examples.
First, referring to the upper diagram of
Hence, when input voltage with the opposite phases (which are not subjected to phase control and are simple) are applied to the first piezoelectric element 3a and the second piezoelectric element 3b, a difference (Of) of 200 Hz is generated between the vibration frequency of the first diaphragm 1a and the vibration frequency of the second diaphragm 1b. Note that the vibration frequencies of the first diaphragm 1a and the second diaphragm 1b are each approximately 20 kHz, and further, the first diaphragm 1a has a higher frequency.
Further, the vibration phase of the first diaphragm 1a and the vibration phase of the second diaphragm 1b are not suitably opposite to each other, and thus a phase difference (shift amount from the opposite phase) is generated.
In the third comparative example, the vibration phase of the second diaphragm 1b is advanced by approximately 50° with respect to the opposite phase of the vibration of the first diaphragm 1a. Thus, in the phase control, the processing of delaying the phase of the input voltage of the second piezoelectric element 3b by 50° with respect to the opposite phase of the input voltage of the first piezoelectric element 3a is performed. By such phase control, the vibration phase of the first diaphragm 1a and the vibration phase of the second diaphragm 1b can be suitably set to be the opposite phases.
Next, referring to the middle diagram of
Hence, when input voltages with the opposite phases (which are not subjected to phase control and are simple) are applied to the first piezoelectric element 3a and the second piezoelectric element 3b, a difference (Of) of 400 Hz is generated between the vibration frequency of the first diaphragm 1a and the vibration frequency of the second diaphragm 1b. Note that the vibration frequencies of the first diaphragm 1a and the second diaphragm 1b are each approximately 20 kHz, and further, the first diaphragm 1a has a higher frequency.
Further, the vibration phase of the first diaphragm 1a and the vibration phase of the second diaphragm 1b are not suitably opposite to each other, and thus a phase difference (shift amount from the opposite phase) is generated.
In the fourth comparative example, the vibration phase of the second diaphragm 1b is advanced by approximately 80° with respect to the opposite phase of the vibration of the first diaphragm 1a. Thus, in the phase control, the processing of delaying the phase of the input voltage of the second piezoelectric element 3b by 80° with respect to the opposite phase of the input voltage of the first piezoelectric element 3a is performed. By such phase control, the vibration phase of the first diaphragm 1a and the vibration phase of the second diaphragm 1b can be suitably set to be the opposite phases.
Next, referring to the lower diagram of
Hence, when input voltages of the opposite phases (which are not subjected to phase control and are simple) are applied to the first piezoelectric element 3a and the second piezoelectric element 3b, a difference (Of) of 1000 Hz is generated between the vibration frequency of the first diaphragm 1a and the vibration frequency of the second diaphragm 1b. Note that the vibration frequencies of the first diaphragm 1a and the second diaphragm 1b are each approximately 20 kHz, and further, the first diaphragm 1a has a higher frequency.
Further, the vibration phase of the first diaphragm 1a and the vibration phase of the second diaphragm 1b are not suitably opposite to each other, and thus a phase difference (shift amount from the opposite phase) is generated.
In the fourth comparative example, the vibration phase of the second diaphragm 1b is advanced by approximately 90° with respect to the opposite phase of the vibration of the first diaphragm 1a. Thus, in the phase control, the processing of delaying the phase of the input voltage of the second piezoelectric element 3b by 90° with respect to the opposite phase of the input voltage of the first piezoelectric element 3a is performed. By such phase control, the vibration phase of the first diaphragm 1a and the vibration phase of the second diaphragm 1b can be suitably set to be the opposite phases.
Note that, in this example, the case where the processing of shifting the phase of the input voltage of the second piezoelectric element 3b is performed in the phase control has been described, but the phase of the input voltage of the first piezoelectric element 3a may be shifted. Alternatively, the phase of the input voltage of the first piezoelectric element 3a and the phase of the second input voltage may be both shifted to perform the phase control.
Referring to the left diagram of
Further, a black line indicates a graph of a case where the phase control is not performed, and a gray line indicates a graph of a case where the phase control is performed. It is found from the left diagram of
Referring to the right diagram of
Further, a black line indicates a graph of a case where the phase control is not performed, and a gray line indicates a graph of a case where the phase control is performed. It is found from the right diagram of
<Manufacturing Apparatus 30 and Manufacturing Method>
Next, a manufacturing apparatus 40 and a manufacturing method for the diaphragm pump 10 according to the second embodiment will be described.
The manufacturing apparatus 40 according to the second embodiment shown in
Referring to
The phase difference measurement unit 38 then measures waveforms of the vibrations of the first diaphragm 1a and the second diaphragm 1b and measures a phase difference between the opposite phases in the vibrations of the first diaphragm 1a and the second diaphragm 1b. Note that the lowest diagram of
Note that the phase difference measurement unit 38 outputs the information of the measured phase difference, as an eigenvalue of the diaphragm pump 10, to the control apparatus 37. The information of the phase difference is stored in, for example, a memory chip (not shown) provided to the diaphragm pump 10. When the diaphragm pump 10 is mounted on an electronic apparatus or the like and used actually, the information of the phase difference is read from the memory chip and is used as the information of the phase control.
The phase difference measurement unit 38 is constituted by, for example, a Doppler displacement meter, but may be constituted by any apparatus as long as it is an apparatus capable of measuring waveforms of the vibrations of the first diaphragm 1a and the second diaphragm 1b.
<Operation Etc.>
In the diaphragm pump 10 according to the second embodiment, the phase control based on a phase difference is performed, so that the vibrations of the first diaphragm 1a and the second diaphragm 1b can be approximated to have the opposite phases without limit. This makes it possible to further improve the driving efficiency of the diaphragm pump 10.
Next, various modified examples according to the present technology will be described.
<Position of Adjustment Portion 11>
In the embodiments described above, the case where the adjustment portion 11 is provided to the piezoelectric element 3 has been described. Meanwhile, the adjustment portion 11 may be provided to a position other than the piezoelectric element 3 in the diaphragm 1.
As shown in
Here, in the case of the pattern in which the resonant frequency of a diaphragm 1 on a low frequency side is increased to match the resonant frequencies of the two diaphragms 1, an adjustment portion 11 formed of a material having a higher elastic modulus than that of the spring portion 6 is formed on the spring portion 6 of the diaphragm 1 on the low resonant frequency side.
Further, in the case of the pattern in which the resonant frequency of a diaphragm 1 on a high frequency side is decreased to match the resonant frequencies of the two diaphragms 1, an adjustment portion 11 formed of a material having a lower elastic modulus and a higher specific gravity than those of the spring portion 6 is formed on the spring portion 6 of the diaphragm 1 on the high resonant frequency side.
Note that the shape of the adjustment portion 11 is not limited to be circular and can be appropriately changed. Further, in the example shown in
As shown in
Here, in the case of the pattern in which the resonant frequency of a diaphragm 1 on a low frequency side is increased to match the resonant frequencies of the two diaphragms 1, an adjustment portion 11 formed of a material having a higher elastic modulus than that of the elastic portion 5 is formed on the elastic portion 5 of the diaphragm 1 on the low resonant frequency side.
Further, in the case of the pattern in which the resonant frequency of a diaphragm 1 on a high frequency side is decreased to match the resonant frequencies of the two diaphragms 1, an adjustment portion 11 formed of a material having a lower elastic modulus (and a higher specific gravity) than that of the elastic portion 5 is formed on the elastic portion 5 of the diaphragm 1 on the high resonant frequency side.
Note that, regardless of the position where the adjustment portion 11 is provided, the adjustment portion 11 is symmetrically formed about the center of the diaphragm 1 (in the horizontal direction), so that the resonant frequency can be suitably adjusted.
Further, the adjustment portion 11 may be provided at two or more locations among the piezoelectric element 3, the spring portion 6, and the elastic portion 5.
<Flexible Board (Power Feed Unit)>
In the example shown in
Note that the shape of the adjustment portion 11 is not limited to be circular and can be appropriately changed. Further, in the example shown in
In the example shown in
<Adjustment Portions 11 on Both First Diaphragm 1a Side and Second Diaphragm 1b Side>
In the above description, the case where the adjustment portion 11 is provided to either the first diaphragm 1a or the second diaphragm 1b has been described. Meanwhile, the adjustment portions 11 may be provided to both the first diaphragm 1a and the second diaphragm 1b.
Note that, if a material having a higher elastic modulus than that of a portion where the adjustment portion 11 is to be provided (piezoelectric element, spring portion, elastic portion) is used as a material for the adjustment portion 11, the amount of the adjustment portion 11 to be provided to a diaphragm 1 on a low resonant frequency side is set to be larger than the amount of the adjustment portion 11 to be provided to a diaphragm 1 on a high resonant frequency side.
Meanwhile, if a material having a lower elastic modulus (and a higher specific gravity) than those of a portion where the adjustment portion 11 is to be provided (piezoelectric element, spring portion, elastic portion) is used as a material for the adjustment portion 11, the amount of the adjustment portion 11 to be provided to a diaphragm 1 on a high resonant frequency side is set to be larger than the amount of the adjustment portion 11 to be provided to a diaphragm 1 on a low resonant frequency side.
Note that the adjustment portion 11 may be formed at a different portion in the first diaphragm 1a and the second diaphragm 1b. For example, the adjustment portion 11 may be provided to the first piezoelectric element 3a on the first diaphragm 1a side, and may be provided to the second elastic portion 5b on the second diaphragm 1b side (the combination is freely determined).
In addition, the adjustment portion 11 may be provided at two or more locations selected from the first piezoelectric element 3a, the first spring portion 6a, and the first elastic portion 5a on the first diaphragm 1a side, and may be provided at two or more locations selected from the second piezoelectric element 3b, the second spring portion 6b, and the second elastic portion 5b on the second diaphragm 1b side.
<Others>
Note that, in the example shown in
The present technology can have the following configurations.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2020-204122 | Dec 2020 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2021/044200 | 12/2/2021 | WO |
