JPS63241447A - Vibrating type transducer - Google Patents

Abstract

PURPOSE:To reduce the quantity of the thermal deformation of a mechanism vibrator and to reduce a temperature error by arranging plural driving elements at a vibration driving part. CONSTITUTION:A diaphragm driving part 20 is provided so as to make a vibrator bottom part 1a perform bending vibration, and the six driving elements 21 are arranged in a link shape at the driving part 20 on the internal surface of the bottom part 1a concentrically about the center of the bottom surface. A connection line 22 connects electrodes 21b and 21b of adjacent elements 21 and five electrodes 21b are connected at the driving part 20 by the connection line 22 so that they are at the same potential. Consequently, even if there is a difference in coefficient of thermal expansion between a diaphragm and the elements 21 which constitute the driving part 20, thermal deforming force to the mechanical vibrator 23 due to the difference in coefficient of expansion and the temperature variation of measurement fluid is small as compared with when the driving part 20 is formed of one element 21. Therefore, the thermal deformation quantity of the vibrator 23 is reduced and the temperature error is reduced.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention & work One circumference fixation 1] When the diaphragm (n) vibrates in the thickness direction of the diaphragm (hereinafter referred to as ")" when the part other than the periphery of the diaphragm vibrates. By detecting the resonant frequency of the diaphragm (sometimes referred to as bending imaging), the fluid Q] that is in contact with the diaphragm is detected.
The present invention relates to a vibratory transducer for measuring density or pressure, particularly a transducer with little temperature error.

[Conventional technology]

FIG. 8 has already been filed by the present applicant. The above-mentioned vibrating transducer Q]-Example Lr) is a configuration diagram showing the main parts in a longitudinal section, and FIG. 9 is a configuration diagram of the piezoelectric actuator 2'I) shown in FIG. 8, and FIG. , 0 is the back view, 1 is the front view, respectively.
FIG. 90 is a sectional view taken along the line XX in the above-mentioned country (see specification of Japanese Patent Application No. 2919F58, No. 61-7).

In FIGS. 8 and 9, 1 is the bottom 1a. A ring-shaped piezoelectric vibrator 2 is fixed on the inner surface of the bottom 1a, and the ring-shaped piezoelectric vibrator 2 is attached to the open end. A bottomed cylindrical thin metal plate vibrating body provided with a
The piezoelectric transducer 2 includes a piezoelectric material film force annular plate-shaped piezoelectric substrate 2a,
It is composed of a first electrode 2b formed on the back surface of the substrate 0, and second and third electrodes 2c+2d formed on the surface of the substrate 2a.

The vibrator 2 is then fixed to the bottom 18 of the vibrator 1 with a 4-conductor adhesive so that the first electrode 2b is electrically Vc-conducted to the bottom 18 of the vibrator 1. 3 is a mechanical vibrator consisting of a vibrator 1 and a vibrator 2; 4 is a cylindrical shape with a bottom; 7) a container with one end of the cylindrical body 5n fixed to the outer surface; 6 is a sled; By screwing the male screw 6a provided on the side surface into the female screw 4b provided at the open end of the container 4, the vibrating body 17) and the stepped portion 4 provided with the collar lb inside the container 4.
7.8 is a housing that fixes the CIC clamping mechanical vibrator 3 in the container 4 and also covers the container 4. 7.8 is a housing in which the mechanical vibrator 3 is inserted into the container 4 as described above. By fixing the vibrator 3 and the container 4, the bottom 4
A first cavity formed between the pendulum 3 and the housing 6; a second cavity formed between the pendulum 3 and the housing 6; A hole 4d is provided, and a through hole 6b is also provided in the housing fivc.
There is. 9 is the second and third electrodes 2C+ provided with the vibrator 2K
2d and the vibrating body l are 4110a, 10b, and I, respectively.
connected via Oc, as described below (g No. 9
The detection circuit is designed to output a, and the conductor 10a-10
C is a through hole 6bVc. As shown in FIG. 10, the detection circuit 9 & U is configured to have Vcm.

Next, the transducer D will be explained using the block diagram shown in FIG. 10. f That is, when the stiffness transducer is first placed in the measuring fluid 11,
G′:c cylinder 5 and through hole 4d in cavity 7? The fluid 11 flows into the cavity 8 through the through hole fib7a'. Then, when the power is turned on to the detection circuit 9, the AC voltage 12a is output from the AC amplifier circuit 12.The voltage is applied to the piezoelectric retractor 2')) second electrode ZCVc,
Therefore, the bottom part 1a of the vibrating body iLn is warped] The mechanical vibrator 3 is driven by the pressure/capturing element 2 at ℃ so as to expand and contract in the radial direction.As a result, the mechanical vibrator 3 bends and vibrates in the thickness direction. Become a VC. Then, the piezoelectric substrate 2 due to bending vibration
a7) Due to the distortion, an AC voltage 13 corresponding to the distortion is generated between the electrodes 2d and 2b and 1] of the vibrator 2, and this voltage 13
&: Positive feedback is provided to the amplifier circuit 12 via the feedback circuit 14.

Then, this positive feedback is performed so as to continue the self-excited vibration of the electrical/mechanical imaging system 0, which is composed of a mechanical imaging system 15 including a mechanical vibrator 3, an amplifier circuit 12, and a feedback circuit 14, which will be described later. In the end, one mechanical vibrator 3 consists of the vibrator 3 and the cylindrical body 5.
an acoustic vibration system 16 consisting of an interior, a through hole 4d, and a cavity 7;
The sound V damage system 17 consisting of the cavity 8 and the through hole 6b, and the aforementioned force machine motion system 159) consisting of the cavity 8 and the through hole 6b) should continue the bending imaging that resonates at the natural frequency F. 18 is AC voltage 1
2a is input, and outputs a pulse frequency D pulse train signal 18a depending on the frequency of the voltage.

The signal generation circuit 18 is configured as described above.
The pulse frequency of the output signal 18a'71 must be equal to the above-mentioned '7') frequency F, but since this OF is the natural frequency of the mechanical imaging system 15D, the value corresponding to the density ρ of the fluid to be measured 11') will be There is. Therefore, by knowing FY, we can know ℃ρ, so %19 is.

Based on this principle, the input pulse train signal 18aV
This calculation circuit performs a predetermined calculation on c and outputs a signal proportional to the density ρ as an output signal 9a. In FIG. 8, each part operates as described in 7 above, and in the end, the density ρ of the fluid 11 is determined by the output signal 9a of the detection circuit.
Alternatively, the pressure of the fluid can be measured.

[Problem that the invention seeks to solve]

Since the transducer shown in FIG. 8 is constructed as described above, the mechanical vibrator 3 has a diameter of 4 ft smaller than 4) in a transducer in which the piezoelectric element 2 is formed in the shape of a disk. As a result, the aforementioned patent application
- As described in the specification of No. 291968, there is an advantage that the density or pressure ηI [constant] and sensitivity are higher than when a disc-shaped piezoelectric vibrator is used.

However, in this case, although the insert 2 is formed into a ring shape and has a machined color, the sensor 2 having different expansion coefficients and the bottom part 1a of the moving body are joined over a wide range using an adhesive. Therefore, due to the temperature change of the measuring fluid 11,
A large thermal deformation occurs in the Cfa mechanical actuator 3vc, and when such thermal deformation occurs, the natural frequency F of the mechanical low dynamic system 15 changes, so eventually.

The problem with the transducer of FIG. 8 is that the measurement results of density or pressure using the transducer (G 9a) may include a large degree error.

An object of the present invention is to reduce the thermal deformation of the mechanical perturber 3, thereby reducing the above-mentioned temperature error.

c.Means for solving problems] The above problem? According to one embodiment of the present invention.

a diaphragm having a fixed periphery; and a diaphragm fixed to at least one surface of the oscillation plate to drive the diaphragm so that the periphery of the oscillating plate moves in the thickness direction of the diaphragm. The resonant frequency of a vibration system comprising a mechanical vibrator comprising a diaphragm drive unit and a measuring fluid brought into contact with the mechanical vibrator is detected, and the measurement is performed based on the detection result of the machine. In those that measure the density or pressure of fluids.

The diaphragm drive section is formed by arranging a plurality of drive elements having a single stiffness in a ring shape, and the adjacent drive elements are completely separated from each other by a thin connection part?
The vibrating transducer is configured such that the vibrating transducer is connected through the vibrating transducer.

[Effect]

With the configuration described above, there is a difference in thermal expansion coefficient between the diaphragm and the drive element that constitutes the diaphragm drive section, and the difference in thermal expansion coefficient is caused by this difference in coefficient of expansion, temperature change of the measured fluid, and VC. The thermal deformation force on the filter mechanical oscillator is smaller than when the diaphragm drive section is formed of a single ring-shaped driving element, and as a result, the amount of thermal deformation in the mechanical oscillator is reduced, resulting in a reduction in temperature error. A small vibrating transducer will be obtained.

〔Example〕

FIG. 1 is an explanatory diagram of the main parts of the vibration transducer 24 shown in FIG. 3 is a block diagram of the diaphragm drive section 20 shown in FIG. 2, FIG. 3 (2) is a plan view, and FIG. 3 (2) is a YY cross-sectional view in FIG. 3 (2).

The main points in FIGS. 1 to 3 that differ from the vibrating transducers shown in FIGS. 8 to 10 are that S@
Since the diaphragm drive unit 20 is provided corresponding to the piezoelectric sensor 2 in order to perform bending imaging on the body bottom 1a, the 4 drive units 20 have six arcuate drive elements 21Y vibrating bodies. The inner surface VC of the bottom part 1a is arranged in a ring shape concentric with the center of the bottom surface and is formed at 1°C. Then, the drive element 21
It consists of a piezoelectric substrate 21a made of a piezoelectric material, each formed in a 7"L1 arc shape, and electrodes zib and 21G formed on the front and back surfaces of this substrate, respectively, and the electrode 2IC and the vibrating body bottom la are electrically connected. [2j! It is fixed to the bottom part 1a using a conductive adhesive so as to pass through. 22 is the electrode 21b of the adjacent axle 21.

21bfX: A connection line to be connected. In the diaphragm drive unit 20, the five electrodes 21b are
Connected to 5th place and 4 more wires 10a? The intervening bead detection circuit 9VC is connected, and the remaining electrode 21b is connected to the detection circuit 9 via the conducting wire 1obe. In the transducer 24 shown in FIG. 1 and text 21,
The dynamic body 1 is connected to a temperature detection circuit 9Vc through a conductor 10c, and the temperature is changed to ℃. The piezoelectric substrate 21a is made of a piezoelectric core material C, which is made of pb(Zr'l"1)Os-based piezoelectric ceramics in this case, and ZnO ceramics may also be used. 23 is the above-mentioned diaphragm. This is a mechanical vibrator consisting of a driving section 20, a connecting line 22, and a vibrating body l.

In the perturbation type transducer 24 shown in FIG. 2, each part is configured as an IC as described above.

In the transducer shown in FIG. 8, the bottom part 1a of the movable body is driven by the diaphragm drive part 20 VC to perform a bending motion, and this bending vibration 411 is caused by f and l, respectively.
Since the acoustic imaging system 1G into which the constant fluid 11 is introduced, the 17 and the mechanical vibrator 23 have the same frequency as the natural frequency vc of the low-motion system 25, the output signal 9a of the detection circuit is ! The signal corresponds to the density of Therefore, the density or pressure of the fluid 11 can be measured by means of the signal 9a. Then, the transducer 24's bending vibration of the bottom part Ha of the vibrating body was suppressed by five vibrations. Is it possible to drive the element 21 and the vibrating body bottom la?
The thermal deformation force exerted on the mechanical vibrator 23Vc due to the difference in the expansion coefficients between and the temperature change of the measuring fluid 11 is similarly smaller than the thermal deformation force acting on the mechanical excavator 3Vc in FIG. is clear. Therefore, if the vibrating transducer is configured as shown in FIGS. 1 to 3, the thermal deformation occurring in one mechanical vibrator 23 will be reduced, and therefore the temperature error in the % measurement result will be reduced.

FIG. 4 shows sample R in the transducer in FIG. 8 with the container bottom 4a and cylindrical body 5 removed to leave the cavity 7 open, and the transducer 24Vc in FIG. This figure is an explanatory diagram of the experimental results conducted once for sample V with cavity 7 open. This figure shows both samples R and V in air at 20°C with mechanical vibrators 3 and 23.
The frequency F'to of each bending vibration when each bending vibration is in the resonance state KL, and the frequency F'to of each bending vibration of the vibrators 3 and 23 when the temperature of the air is set to t° C. and a similar resonance state is obtained. One was created by measuring the frequency Ft.

From this figure, it is clear that the use of the divided drive element 21 results in a transducer with smaller temperature errors. In this experiment, for both samples R and V, the inner diameter of the Vc movable body bottom part Ha was 24 [mm], the outer diameter of the vibrator 2 or the dimensions of the 1 drive part 200 corresponding to this outer diameter was 23 [■], and the vibrator was 2 or the dimension of the drive part 20 corresponding to this inner diameter is 18 CM
:l.

Fig. 5 is an explanatory diagram of the experimental results, which is different from Fig. 4. In this experiment, both the above-mentioned samples R and V were left in air where the temperature changed over time as shown in the figure, and then at the time shown in the figure. It was created by measuring the frequency of bending vibration in the same way as in Fig. 4.

F in the diagram! +l I F t has the same meaning as in Figure 4. It is also clear from FIG. 5 that the use of the one-segment drive element 21 reduces the temperature error in density or pressure measurements.

FIG. 6 is a surface view of a diaphragm drive section 26 that is different from the above-mentioned diaphragm drive section 20. In this case, six drive elements 27 constituting the drive section 26 move the annular pattern from the center of the pattern. It is formed into a shape obtained by dividing the distance by a linear dividing line having a predetermined value other than zero. In FIG. 2, it is clear that the aforementioned thermal deformation can be reduced even if the vibrating body bottom portion 1a is driven by the above-mentioned driving portion z6.
Since it has the above-described shape, there is an advantage that the driving force for the bottom portion la is larger than that for the driving portion 20.

FIG. 7 is a configuration diagram of the diaphragm driving section 28, which is different from the above-mentioned one. In this case, the drive unit 28 has a circular top plate-shaped piezoelectric substrate 28a, and this substrate 28aVC is provided with grooves 29 along three straight lines passing through the center of the substrate, and as a result, the substrate 28a is Six thin parts 28a1 formed by the groove 29rc and six thick parts 28a2 adjacent to the face part 28a1.
It is composed of ℃ and ℃.

A VC electrode 21b is provided on the front surface of the thick portion 28a2, and a ring-shaped electrode 28b is provided on the back surface of the substrate 28H. Since the diaphragm drive unit 28 is configured with a VC as described above, the drive unit 28 is used instead of the C% drive unit 20 in the transducer shown in FIG. If the wiring is done as shown in FIG.
It is clear that the density or pressure of 1 can be measured.

In this case, in the drive section 28, the thick portion 28a
2 are connected by the thin wall part 28al, so
The aforementioned thermal deformation force generated in the mechanical vibrator consisting of the drive section 28 and the vibrating body l is larger than in the case of FIG. 2, but smaller than in the case of FIG. 8, resulting in a transducer with a small temperature error. −Sa will be obtained. Kakut JJ Club 28
If this is adopted, the six thick portions 28a2 are not separated, making it easier to manufacture the vibration transducer.

In each of the above-mentioned embodiments, the diaphragm drive section is shaped like blj, L by distributing six arc-shaped drive elements in a ring shape.

and all adjacent driving elements are separated [1-
The bending vibration of the bottom portion 1a of one vibrating body is driven by five of the six drive elements described above, and the remaining one However, the present invention is not limited to the number and shape of the drive elements as described above (the present invention is not limited to the number and shape of the drive elements as described above). The number of elements and the number of drive elements provided with electrodes for voltage detection may be different from the above numbers by I1, and the shape of the drive elements may be strip-like. It is.

Furthermore, in each of the above-described embodiments, a piezoelectric vibrator, that is, an electrostrictive driving element was used to drive the vibrating body bottom part Ha, but according to the present invention, a pre-distribution straining driving element was used instead.
, S skewness may be used.

〔Effect of the invention〕

As described above, in the VC1 of the present invention, at least -cliliVc of this diaphragm is fixed to the imaging plate whose peripheral edge is fixed, and the Kffi moving plate is fixed so that the portion of the diaphragm excluding the periphery vibrates in the thickness direction of the diaphragm. A mechanical vibrator comprising a diaphragm drive unit that drives Is the diaphragm drive unit used to measure the density or pressure of the measured fluid based on the results? : A plurality of circular arc-shaped drive elements having strainability are arranged in a ring shape, and adjacent drive elements are either completely separated or connected through a thin connection part. Sukashi Kobe constructed a mobile transducer.

Therefore, when configured as described above, a diaphragm and a perturbation plate!
Even if there is a difference in coefficient of thermal expansion between the drive element and the drive element that constitutes the AtM section, the thermal deformation force on the mechanical vibrator caused by this difference in coefficient of expansion and the temperature change of the measured fluid will cause the vibration plate drive section to When formed by a single ring-shaped drive element, the amount of thermal deformation in one mechanical vibrator is small, and as a result, in the present invention, the amount of thermal deformation in one mechanical vibrator is small. In addition, in the present invention, C is that the plurality of drive elements constituting the diaphragm drive S are not rigidly connected, so even if ceramics are used in the diaphragm drive part, This also has the effect of preventing cracks from occurring in the ceramics of the IC if a rapid temperature change is applied to the vibrating transducer.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the main part of one embodiment of the present invention, and FIG.
Figure 3 is a configuration diagram of the embodiment showing the mounting part, Figure 3 is a configuration diagram of the diaphragm drive unit shown in Figures 1 and 2; It is a Y-YM plane view from Figure to VcS. FIGS. 4 and 5 show different experimental results, and FIGS. 6 and 7 are explanatory views of the structure of the diaphragm drive unit, which are different from those shown in FIG. 3. FIG. 7(5) is a surface view, and FIG. 7(5) is a side view. FIG. 8 is a configuration diagram of a conventional vibration transducer. Figure 9 is a configuration diagram of the Wang Qian oscillator shown in Figure 8. FIG. 9(2) is a back view, FIG. 9C) is a front view, and FIG. 9B) is a cross-sectional view taken along line XX in FIG. 94. 1st
FIG. 8 is a block diagram of the vibration transducer shown in FIG. 1 and FIG. 8; 1a... Loss body bottom g, tb... Brim,
2... Piezoelectric vibrator, 3.23... Mechanical vibrator, 11... Measuring fluid. 15.25... Vibration system, 20.26.28.
...Diaphragm drive unit, 21.27...Driving element, 24...Vibration transducer, 28
a1...Thin part. , °) I'e person Ir Physician Yamaguchi Iwao ゞ'. Paper note 1! ! 1 Palette 2 Figure (4) <8) Note 3 Mouth 1b Note 6 Figure [A (8) Iris q Mouth

Claims (1)

[Claims] a diaphragm having a fixed periphery; and a diaphragm drive unit fixed to at least one surface of the diaphragm to drive the diaphragm so that a portion of the diaphragm other than the periphery vibrates in the thickness direction of the diaphragm. Detecting the resonance frequency of a vibration system consisting of the mechanical vibrator and a measuring fluid that is in contact with the mechanical vibrating element, and determining the density or pressure of the measuring fluid from the detection result. In the device to be measured, the diaphragm drive section is formed by arranging a plurality of drive elements having strainability in a ring shape, and adjacent drive elements are completely separated, or a thin connection part is formed. A vibrating transducer characterized in that the vibrating transducer is connected via a vibrating transducer.