JP2604693B2 - How to fix the piezoelectric diaphragm - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for fixing a piezoelectric vibrating plate, and more particularly, to a method for applying a piezoelectric vibrating plate to a vibrator using the piezoelectric vibrating plate. To how to fix to.

[Prior Art] Conventionally, various types of vibrators for detecting changes in the natural frequency of a piezoelectric vibrating plate have been devised (Japanese Patent Publication No. 47-50756, Japanese Patent Application Laid-Open No. 48-60890, Japanese Utility Model Publication No. 61−8344,
U.S. Pat. No. 3,617,780, JP-A-56-21029, etc.) and a typical type thereof is shown in FIG.

In this vibrator, grooves 53 having step portions 52 are formed on the upper and lower surfaces of a cantilever 51, and both ends of a piezoelectric vibration plate 55 in which an excitation electrode 54 is attached to each step portion 52 of these grooves 53.
55a is fixed, utilizing the fact that when a load F is applied to the free end of the cantilever 51, each piezoelectric vibration plate 55 generates an elongation / compression stress and changes its natural frequency. To detect the load F and the displacement of the free end.

In this type of vibrator, the conditions for fixing the piezoelectric vibrating plate are as follows:
In terms of its function, it has a very important significance, but in general, a method of bonding to the cantilever is adopted, and according to the above example, both ends 55 a of the piezoelectric vibration plate 55 are The step 52 is fixed by bonding with an epoxy-based adhesive or sealing glass.

However, for example, when using quartz as the piezoelectric diaphragm and steel as the cantilever,
Their Young's modulus is about 84 × 10 ⁴ [kg / cm ² ], about 2
10 × 10 ⁴ [kg / cm ² ], whereas the Young's modulus of epoxy-based adhesive and sealing glass is about 10 × 10 ⁴ [kg / c]
m ² ] and about 50 × 10 ⁴ [kg / cm ² ], and when a load is applied, the effect of the bonded portion occurs.

That is, in the above example, as shown in FIG. 18, the adhesive 56 interposed between the step portion 52 of the cantilever 51 and the piezoelectric vibration plate 55 receives a force in the shearing direction, and the sensitivity of the vibrator ( Although the frequency change) must be proportional to the load F applied to the vibrator, the deformation of the adhesive 56 causes non-linearity and hysteresis in its sensitivity and deteriorates the zero return property.

As a result, there is a disadvantage that the sensitivity and the measurement error occur, and the load and the displacement cannot be properly measured.

Therefore, it is preferable that the piezoelectric vibrating plate is fixed by a mechanical narrow pressure, and a shrink fit method is employed as the mechanical fixing means.

The vibrator to which the piezoelectric vibrating plate is fixed by this shrink fitting method has a configuration as shown in FIG. 19, and the holder portion 58 of the piezoelectric vibrating plate 57 includes a ring 59, a half-moon-shaped boss 60, and a cantilever 61.
And a flange portion.

The assembly process of this oscillator is shown in FIG.
Is expanded by heating, the flange portion of the cantilever 61,
The end portion of the piezoelectric vibrating plate 57 and the boss 60 are superimposed on the ring 59 in a state of being superposed, and the flange 59 of the cantilever 61 and the boss are The end of the piezoelectric vibrating plate 57 is sandwiched between 60.

[Problem to be Solved by the Invention] As described above, when the fixing method of the piezoelectric vibrating plate by the shrink fit method is used, various technical problems that occur in the vibrator when the adhesive is used can be solved. Conversely, the following problem occurs.

In order to optimize the narrow pressure of the piezoelectric vibrating plate 57, it is necessary to process the ring 59, the boss 60, and the cantilever 61 with high accuracy with respect to the thickness of the piezoelectric vibrating plate 57. Also, ring 59
It is extremely difficult to adjust the narrow pressure in relation to the amount of shrinkage.

In the assembling process, a setting process of each component and a heating / cooling process of the ring are required, which makes the operation complicated and takes time.

As described above, it is extremely difficult to adjust the narrow pressure on the piezoelectric vibrating plate 57. On the other hand, since the piezoelectric vibrating plate 57 is made of a hard and brittle material, cracks often occur in the piezoelectric vibrating plate 57 during the assembly stage. The production defect rate of the child becomes very high. The defect rate of the vibrator manufactured by the shrink-fitting method is about 70 to 80%, which is extremely poor.

In view of the above, the present invention provides a fixing method capable of adjusting a narrow pressure on a piezoelectric vibration plate with high accuracy by a simple process in a fixing means of a piezoelectric vibration plate by a non-adhesion method. It was created to be easily manufactured.

[Means for Solving the Problems] In order to achieve the above object, the present invention employs the following methods.

In the first invention, a notch is formed on one of two wall surfaces facing in parallel, a boss having a parallel side surface, and a notch formed on one of the side surfaces, and the piezoelectric vibrating plate, After interposing the notch on the wall and the notch on the boss between the two walls, the steel plate is pressed into the hole formed by the notches, so that the piezoelectric vibrating plate is attached to the side of the wall and the boss. The present invention relates to a method for fixing a piezoelectric vibrating plate sandwiched therebetween.

According to a second aspect of the present invention, a slit is formed in the board body for inserting the piezoelectric vibrating plate, and a hole is formed in the vicinity of the slit, and after the piezoelectric vibrating plate is inserted in the slit, steel is inserted into the hole. The present invention relates to a method for fixing a piezoelectric diaphragm in which a piezoelectric diaphragm is sandwiched between wall surfaces of a slit by press-fitting a sphere.

The third invention relates to an improvement of the second invention, wherein a slit is formed on a surface of the disk body on the steel ball pressure flow side, the slit being formed in parallel with the slit into which the piezoelectric vibration plate is inserted and passing through a hole. The present invention relates to a method for fixing a piezoelectric vibrating plate in which a sphere is pressed into the hole.

In the fourth invention, a slit having a width smaller than the thickness of the piezoelectric vibrating plate is formed on the board, and the slit is expanded by applying a bending external force to the board, and the piezoelectric vibrating plate is inserted into the slit in that state. Thereafter, the present invention relates to a method of fixing a piezoelectric diaphragm in which a piezoelectric diaphragm is sandwiched between wall surfaces of a slit by releasing an external bending force applied to a board body.

The fifth invention provides a plate body in which a slit into which a piezoelectric diaphragm is inserted is supported, both ends are supported with a direction perpendicular to the slit forming direction as a span, and the piezoelectric diaphragm is inserted into the slit. The present invention relates to a method of fixing a piezoelectric vibration plate in which a piezoelectric vibration plate is sandwiched between wall surfaces of a slit by bringing a span portion and a support side close to each other with a screw tightening force.

[Operation] In the first invention, when a steel ball is pressed into the hole, the boss narrows the piezoelectric vibrating plate against the wall surface, and the piezoelectric vibrating plate is mechanically fixed by the narrow pressure. This assembling operation is naturally performed at room temperature, and can be performed by a very simple process of inserting a steel ball into a hole using a hand press or the like after interposing a piezoelectric vibrating plate and a boss between both wall surfaces. The narrow pressure of the piezoelectric vibrating plate is adjusted only by the relationship between the diameter and the hole of the steel ball. Generally, steel balls manufactured with extremely high dimensional accuracy are commercially available. Since adjustment is also possible, a required narrow pressure can be obtained with high accuracy.
As a result, it is possible to accurately fix the piezoelectric vibrating plate without generating cracks or the like with a uniform narrow pressure.

In the second invention, the boss is not used unlike the first invention,
By simply pressing a steel ball into a hole formed near the slit, the piezoelectric vibrating plate is narrowed in the slit and mechanically fixed. This method utilizes the fact that when the inner surface of the hole is pressed by the press-fitting of a steel ball, a strain is generated inside the board near the hole and the slit becomes narrower. Therefore, the narrow pressure can be adjusted only by the relationship between the diameter of the hole formed in the board and the diameter of the steel ball, and the required narrow pressure can be obtained with high accuracy as in the first invention, and the structure can be improved. Simplification and ease of assembly work can be achieved.

The third invention is an improvement over the second invention for achieving a uniform narrow pressure. That is, in the second invention, when a steel ball is press-fitted into the hole, a large strain is generated in the region near the hole, but the strain is reduced as the distance from the hole is increased, and the steel is inevitably separated from the region near the hole and the hole. Since the narrow pressure on the piezoelectric vibrating plate differs in each slit portion of the region, cracks may be generated in the piezoelectric vibrating plate. In the present invention, the separately formed slit has a function of uniformly dispersing the strain generated inside the board, and generates a uniform narrow pressure on the wall surface of the slit for fixing the piezoelectric vibrating plate.

The fourth invention employs a method in which each of the above-mentioned inventions presses a steel ball into a hole, whereas the piezoelectric vibrating plate is narrowed in a slit by using only the elasticity of a board, and mechanically. Fix it.
According to this method, the restoring force of the board when the external bending force is released supplies a narrow pressure, and the narrow pressure is determined by the relationship between the thickness of the piezoelectric vibrating plate and the shape of the slit. Therefore, if the shape and size of the slit are adjusted in accordance with the thickness of the piezoelectric vibrating plate, a predetermined narrow pressure can be obtained, and the structure of the fixing portion can be extremely simplified.

In the fifth invention, the piezoelectric vibrating plate is narrowed in the slit by the tightening force of the screw and mechanically fixed. In this method, a narrow pressure is obtained by utilizing the fact that the plate is bent toward the support side by the tightening force of the screw, thereby narrowing the slit. Therefore, even after the piezoelectric diaphragm is sandwiched between the slits, the narrow pressure can be easily adjusted by turning the screw.

Examples Hereinafter, examples of the present invention will be described with reference to the drawings, taking as an example the case of manufacturing a vibrator using a piezoelectric vibrating plate.

Example 1 The structure of this vibrator is shown in FIG. 1 (sectional view in the axial direction) and FIG. 2 (sectional view taken along the line AA in FIG. 1). Have the same structure, the holder 1-1 shows a state before press-fitting the steel ball, and the holder 1-2 shows a state after press-fitting the steel ball.

In the figure, reference numeral 2 denotes a semilunar notch at a symmetric position on the inner peripheral surface.
Rings 3-1 and 3-2 in which 2a and 2b are formed are constituted by an arc side surface and a chord side surface in which the side surface is inscribed in the ring 1, and a half-moon-shaped notch 3-1a, 3- in the center of the arc side surface. Boss with 2a formed,
Reference numerals 4-1 and 4-2 denote piezoelectric vibrating plates having electrodes formed on the front and back, and reference numeral 5 denotes a cantilever portion.

As shown in the holder 1-1 in FIG. 1, each of the above-mentioned components is attached to both sides of the cantilever 5 by the piezoelectric vibrators 4-1 and 4-
2 and the bosses 3-1 and 3-2 so that the notches 2a and 2b on the ring 2 side and the notches 3-1a and 2-2a of the bosses 3-1 and 3-2 face each other. After fitting and setting inside, the steel balls 6-1 and 6-2 are pressed into the holes defined by the cutouts (2a and 3-1a, 2b and 3-2a) using a hand press. . When the steel balls 6-1 and 6-2 are press-fitted, they become as shown in the holder part 1-2 of FIG.
1,3-2 is pressed toward the center of the ring 2 and the boss 3-1,3−
The piezoelectric vibrating plates 4-1 and 4-2 are narrowed and mechanically fixed between the chord side surface of the second and the side surface of the cantilever portion 5.

In this case, the narrow pressure is applied to the notch (2a and 3-1a, 2b and 3-2
Determined by the Saddle-eye relationship between the hole constituted by a) and the steel balls 6-1 and 6-2, generally commercially available steel balls 6-6 and 6-2 are used.
The dimensional tolerance of the diameter of 1,6-2 is extremely small, and when finely adjusting the narrow pressure, the diameter can be adjusted with extremely high precision by applying chrome plating to the steel balls 6-1 and 6-2. Since the adjustment can be performed, a required narrow pressure can be easily obtained.

In this embodiment, a quartz plate is used as the piezoelectric diaphragm,
When a resonator having the characteristics shown in Table 1 is manufactured, the probability of cracks occurring in the quartz plate, that is, the defect rate is 15%.
% To 25%, and the rejection rate was drastically reduced as compared with the conventional shrink fit method. As shown in FIG. 3, the various characteristics shown in Table 1 are obtained by mechanically completely fixing one of the holders 1-1 and 1-2 to the fixed wall 7 and applying an external force to the other holder. Then, the load / displacement data was obtained by the measurement system shown in FIG. Also, Table 1 compares the characteristics of a conventional vibrator manufactured by the bonding method when tested under the same external force application condition and measurement system with the vibrator of the present embodiment.
It is understood that the vibrator of this embodiment is extremely excellent in characteristics related to non-linearity, hysteresis, return to zero, and creep, which are directly affected by the fixing condition of the quartz plate.

Example 2 The structure of this vibrator is shown in FIG. 4 (a sectional view in the axial direction:
5 (cross-sectional view taken along the line BB in FIG. 4) shown in FIG.
Reference numerals 1 and 8-2 have the same structure, and the holder portion 8-1 shows a state before press-fitting the steel ball, and the holder portion 8-2 shows a state after press-fitting the steel ball.

In the figure, 9 is a ring, 10 is a cantilever, 11-1,
11-2 is a piezoelectric diaphragm. A side view of the cantilever 10 in the present embodiment is shown in FIG. 6, and a flange portion 10a fitted to a ring is integrally formed at both ends thereof.
The flange 10a has two slits 10b into which the piezoelectric vibrating plates 11-1 and 11-2 are fitted, and two holes 10c.

In assembling, first, slit 10 of cantilever 10
The piezoelectric vibrating plates 11-1 and 11-2 are inserted into the b from the side, and the flange portion 10a is inserted into the ring 9, and then the steel ball 12 is press-fitted into each hole 10c of the flange portion 10a. Due to this press-fitting, a strain is generated around each hole 10c of the flange portion 10a. On the other hand, since the circumference of the flange portion 10a is constrained by the ring 9, the width of the slit 10b is narrowed, whereby the piezoelectric vibration plate 11-1 and 11-2 are narrowed between both walls of the slit 10b and mechanically fixed.

This narrow pressure is determined mainly by the relationship between the hole 10c and the steel ball 12, and has the same effect as in the first embodiment. However, since the boss is not used, the structure of the holders 8-1, 8-2 is simplified. And the manufacturing process is simplified. Although the relationship between the hole 10c and the steel ball 12 is more delicate than in the first embodiment, the precision of the diameter of the steel ball 12 can be set high, so that it is easy to obtain a required narrow pressure.

Embodiment 3 This embodiment is different from Embodiment 2 in that a ring is not used and the holder section is constituted only by a board. That is, in the second embodiment, of the strain of the flange portion 10a caused by the press-fitting of the steel ball 12, relatively large strain is limited to a region close to the hole 10c, and the ring 9 exists when the periphery of the flange portion 10a is wide. The focus is on the point that the narrow pressure at the slit 10b can be secured without doing so.

FIG. 7 is an axial sectional view of the vibrator not using the cantilever (however, a sectional view taken along the line EE in FIG. 8), and FIG. 8 is a sectional view taken along the line DD in FIG.

In this vibrator, both ends of the piezoelectric vibrating plates 13-1 and 13-2 are fixed only by the holders 14-1 and 14-2 which are board bodies. The holder portions 14-1 and 14-2 are formed with two slits 14a, and a hole 15 is formed near each slit 14a. The four holes 16 formed at the corners in FIG. 8 are for attaching the holder 14-1 or 14-2 to the fixed wall surface.

In assembling, first, the piezoelectric vibrating plates 13-1 and 13-2 are inserted into the slits 14a of the holder portions 14-1 and 14-2, and each hole 1
The width of the slit 14a is reduced by press-fitting the steel ball 17 into 5, and the piezoelectric vibrating plates 13-1 and 13-2 are narrowed between the wall surfaces of the slit 14a and mechanically fixed. Accordingly, although the principle is the same as that of the second embodiment, the structure of the holder portions 14-1 and 14-2 can be simplified and lightened because the ring 9 is not used.

This vibrator uses a total of eight steel balls 17 and a piezoelectric vibrator 13-
1, 13-2 are fixed, but the number of steel balls 17 to be fixed is arbitrary, and holes 15 as many as the number of steel balls 17 to be used are appropriately formed near slits 14a. 15 holes each
The steel balls may be press-fitted into each. How to set the diameter of the steel ball 17 and the diameter of the hole 15 corresponding to the steel ball 17 is also arbitrary, and the design may be changed in accordance with the required narrow pressure. By appropriately selecting the number and diameter of the steel balls 17 and the positions of the holes 15 in this way, there is an advantage that the distribution of the narrow pressure on the piezoelectric vibrating plates 13-1 and 13-2 can be made uniform. The vibrator shown in FIGS. 9 and 10 has a total of four steel balls.
The vibrator shown in FIGS. 11 and 12 uses 17 steel balls 17 in total. (The ninth
12 to 12, the same reference numerals as those in FIGS. 7 and 8 denote the same parts and portions. As means for making the distribution of the narrow pressure uniform, other than the method of selecting the number and diameter of the steel balls 17 and the diameter and position of the hole 15 as described above, FIGS. (The same applies to the ones with.). As shown in FIG. This slit 18 is formed parallel to the slit 14a and along a line passing through the hole 15, and when the steel ball 17 is pressed into the hole 15,
As a result, the strain is dispersed in the slit direction, and the narrow pressure is evenly distributed. That is, only the hole 15 has a drawback that a strong narrow pressure is generated only in a section near the hole 15 and the narrow pressure is attenuated as the distance from the hole 15 increases. 1,
13-2 may be broken or the characteristics as a piezoelectric element may be affected. However, such a problem can be solved by making the narrow pressure uniform by the slit 18. There is also an advantage that a relatively large narrow pressure can be secured even if the hole 15 is formed at a position distant from the slit 14a.

Embodiment 4 Unlike Embodiments 1 to 3, this embodiment relates to a method in which a piezoelectric vibrating plate is narrowly pressed to a slit and mechanically fixed without using steel balls.

FIG. 15 is a cross-sectional view showing the process, in which 20 is a holder having a slit 20a having a width slightly smaller than the thickness of the piezoelectric vibrating plate, 21 is a piezoelectric vibrating plate, 22a is a main body of an assembling jig, 22b Denotes a clamper portion of the jig, and 22c denotes a bolt.

In assembling, first, the end of the holder 20 is fixed between the clamper 22b and the main body 22a of the jig by the bolt 22c. Next, a bending external force is applied to the position and direction indicated by the holder section 20 to expand the slit 20a, and in this state, the piezoelectric vibrating plate 21 is inserted into the slit 20a. When the external bending force applied to the holder 20 is released after the piezoelectric vibration plate 21 is inserted, the width of the slit 20a will be returned to the original width by the elastic restoring force of the thick portion 20b formed below the slit 20a. However, since the piezoelectric vibrating plate 21 is interposed, the restoring force is a narrow pressure on the piezoelectric vibrating plate 21 by the wall surface of the slit 20a.

According to this method, since a steel ball is not used, the process is extremely simplified, and a required narrow pressure can be obtained only by adjusting the width and the depth of the slit 20a with respect to the thickness of the piezoelectric vibrating plate 21. There is an advantage that can be.

Further, as shown in FIG. 15a, when a portion 23 having a wide slit width is formed at the bottom of the slit 20a, or when a sleeve 24 is formed as shown in FIG.
Can improve the adhesion within the slit 20a,
More secure fixing can be realized.

Embodiment 5 This embodiment also relates to a method of mechanically fixing the piezoelectric vibrating plate by narrowing the pressure on the slit without using steel balls.

FIG. 16 is a cross-sectional view showing a state in which the piezoelectric vibrating plate is sandwiched between slits, where 31-1 and 31-2 are piezoelectric vibrating plates, and 32 is a slit into which the piezoelectric vibrating plates 31-1 and 31-2 are inserted. A reference numeral 33 denotes a support for supporting both ends of the plate 32. A screw hole is formed at a substantially central portion of the plate 32, and a hole through which the screw 34 passes is formed at a portion of the support 33 facing the screw hole of the plate.

In the assembly, first, as shown in the drawing, the plate 32 is temporarily fixed to the support 33 with screws 34, and the piezoelectric vibrating plates 31-1, 31-2 are inserted into slits of the plate 32, and then the screws 34 By tightening, the piezoelectric vibrating plates 31-1 and 31-2 are narrowed between both walls of the slit and mechanically fixed. That is, by tightening the screw 34, the central portion of the plate 32 bends toward the support 33 side, thereby narrowing the slit width. However, since the piezoelectric vibrating plates 31-1, 31-2 are interposed, the screw 34 , The two wall surfaces of the slit narrow the piezoelectric vibrating plates 31-1 and 31-2.

According to this method, there is an advantage that the narrow pressure on the piezoelectric vibrating plates 31-1 and 31-2 can be freely adjusted by adjusting the tightening of the screw 34 in the assembling stage.

Also in this method, if the structure of the slit portion shown in FIG. 15a or FIG. 15b is adopted, more secure fixing conditions can be realized.

[Effects of the Invention] The inventions of claims (1) to (5) all enable the piezoelectric vibrating plate to be mechanically fixed, simplify the process, and increase the narrow pressure on the piezoelectric vibrating plate. Be able to adjust with precision. As a result, it is possible to manufacture a vibrator having excellent characteristics without causing cracks or the like in the piezoelectric vibrating plate.

Further, the invention of each claim individually has the following technical effects.

According to the invention of claim (1), the narrow pressure can be adjusted with high accuracy by adjusting the diameter of the hole formed by the notch or the steel ball pressed into the hole. In addition, the presence of the boss has an advantage that the narrow pressure on the piezoelectric vibrating plate can be made uniform over the entire fixed portion.

According to the invention of claim (2), the structure of the fixed portion of the piezoelectric vibrating plate is simplified because only the distortion of the board caused by the press-fitting of the steel ball is used and no boss is used.

According to a third aspect of the present invention, in the second aspect of the present invention, a slit for dispersing the strain is formed, thereby making it possible to equalize a narrow pressure on the piezoelectric vibrating plate.

According to the invention of claim (4), since the piezoelectric vibrating plate is clamped during the work of applying and releasing the external bending force to the board without using the steel ball, the number of parts is reduced and the assembling process is further simplified. I do. Further, there is an advantage that the structure of the fixed portion can be simplified, and the narrow pressure on the piezoelectric vibration plate can be made uniform.

The invention of claim (5) has, in addition to the effect of the invention of claim (4), the advantage that the narrow pressure can be freely adjusted with a screw in the assembling stage.

[Brief description of the drawings]

1 is an axial cross-sectional view of the vibrator, FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1, FIG. 3 is a diagram showing a load / displacement measuring system using the vibrator, and FIG. FIG. 5 is a cross-sectional view of the vibrator in the axial direction (however, a cross-section taken along the line CC in FIG. 5), FIG. 5 is a cross-sectional view taken along the line BB in FIG. 4, FIG. Is an axial sectional view of the vibrator (however, a sectional view taken along the line EE in FIG. 8), and FIG.
9 is an axial sectional view of the vibrator (however,
10 is a sectional view taken along the line FF in FIG. 9, FIG. 10 is a sectional view taken in the axial direction of the vibrator (however, an II line in FIG. 12). FIG. 12 is a sectional view
11 is a sectional view taken along the line HH in FIG. 11, FIG. 13 is a partial sectional view in the axial direction of the vibrator (however, a sectional view taken along the line KK in FIG. 14), and FIG. 14 is an arrow JJ in FIG. Sectional view, 15th
FIGS. 15A and 15B are cross-sectional views illustrating a structure of a slit portion, FIG. 16 is a cross-sectional view illustrating a fixing portion of a piezoelectric vibrating plate, and FIG. , FIG. 18 is a side view showing a bonded portion of the piezoelectric vibrating plate of the vibrator, FIG. 19 is an external perspective view of a vibrator to which the piezoelectric vibrating plate is fixed by shrink fitting, FIG. FIG. 20 is a perspective view showing an assembling process of the same vibrator.

Claims (5)

(57) [Claims] A boss having a notch formed on one of two wall surfaces facing in parallel and having a parallel side surface and a notch formed on one of the side surfaces, and a piezoelectric vibrating plate are formed. After interposing the wall so that the notch on the wall and the notch on the boss face each other, press the steel ball into the hole formed by both the notches to move the piezoelectric vibrating plate between the wall and the side of the boss. A method for fixing a piezoelectric vibrating plate, characterized by being sandwiched between. 2. A slit is formed in a board body for inserting a piezoelectric vibrating plate, and a hole is formed in the vicinity of the slit.
A piezoelectric vibrating plate fixing method, comprising: inserting a piezoelectric vibrating plate into the slit; and press-fitting a steel ball into the hole to sandwich the piezoelectric vibrating plate between the slit wall surfaces. 3. A slit which is parallel to a slit into which the piezoelectric vibrating plate is inserted and which passes through a hole is formed on a surface of the board on a steel ball press-in side, and a steel ball is pressed into the hole. The method for fixing a piezoelectric diaphragm according to claim 2. 4. A slit having a width smaller than the thickness of the piezoelectric vibrating plate is formed in the board, and the slit is expanded by applying a bending external force to the board, and in this state, the piezoelectric vibrating plate is inserted into the slit. A method for fixing a piezoelectric vibrating plate, wherein a piezoelectric vibrating plate is sandwiched between wall surfaces of a slit by releasing an external bending force applied to a board body. 5. A plate body having a slit into which a piezoelectric vibration plate is inserted is supported at both ends with a span perpendicular to the slit forming direction, and the piezoelectric vibration plate is inserted into the slit. A piezoelectric vibrating plate fixing method, wherein a piezoelectric vibrating plate is sandwiched between wall surfaces of a slit by bringing a portion and a support side close to each other with a screw tightening force.