JP6247556B2 - Piezoelectric vibration unit and piezoelectric speaker - Google Patents

Description

  The present invention relates to a piezoelectric vibration unit and a piezoelectric speaker for propagating vibrations to an attached diaphragm or casing to function as a speaker.

  As a speaker for an acoustic device or the like, a piezoelectric speaker in which vibration is transmitted using a piezoelectric vibrator is known. For example, Patent Literature 1 discloses a piezoelectric vibration generator in which both ends of a piezoelectric diaphragm are supported by a base portion.

  FIG. 4 is a cross-sectional view illustrating a conventional piezoelectric speaker. A conventional piezoelectric speaker 30 which is a piezoelectric vibration generating device disclosed in Patent Document 1 includes a piezoelectric bimorph in which piezoelectric elements 32 are respectively attached to both main surfaces of an elastic plate 31. Further, weights 34 are connected to both ends in the longitudinal direction of the elastic plate material 31, and support portions 33 are respectively disposed on the elastic plate material 31 between the weight 34 and the piezoelectric element 32. The support portion 33 is fixed to the base portion 35, and the central portion of the piezoelectric element 32 is connected to the vibration plate 37 via the connecting portion 36.

  With this configuration, the conventional piezoelectric speaker 30 vibrates the weight 34 by vibrating the piezoelectric element 32 at a predetermined frequency, and the vibration plate 37 via the connecting portion 36 by the inertia force generated by the resonance vibration of the weight 34. The vibration is transmitted to.

JP 2007-300426 A

  In the conventional configuration, the vibration is propagated to the elastic plate 31 by vibrating the piezoelectric element 32, and the weight 34 connected to the end portion in the longitudinal direction of the elastic plate 31 is vibrated. Then, the vibration again propagates from the weight 34 to the elastic plate member 31, and the vibration is transmitted to the vibration plate 37 via the connecting portion 36 arranged at the center of the piezoelectric element 32.

  Therefore, the vibration of the piezoelectric element and the vibration due to the weight interfere with each other, and there is a problem that the propagation efficiency of the vibration to the diaphragm that is the object of vibration is reduced.

  Therefore, an object of the present invention is to provide a piezoelectric vibration unit and a piezoelectric speaker having excellent propagation efficiency.

  In order to solve the above problems, a piezoelectric vibration unit according to the present invention includes a rectangular first conductor plate, support portions that support both ends of the first conductor plate in the longitudinal direction, and the first conductor plate. A plate-like piezoelectric element fixed to at least one main surface of the conductor plate; a first connecting portion formed on at least a part of one side surface parallel to the longitudinal direction of the first conductor plate; A second connecting portion formed on at least a part of the other side surface parallel to the longitudinal direction of the first conductor plate, a first weight connected to the first connecting portion, and the second connecting portion. And a second weight connected to the second weight.

  In the piezoelectric vibration unit according to the aspect of the invention, it is preferable that the first connecting portion and the second connecting portion are arranged symmetrically about the longitudinal direction of the first conductive plate.

  In addition, the first conductor plate of the piezoelectric vibration unit of the present invention is bent by bending vibration of the piezoelectric element, and the first connection portion and the second connection portion have an amplitude of the first conductor plate. It is desirable to form at the maximum position.

  The piezoelectric vibration unit of the present invention further includes a rectangular second conductive plate and a rectangular third conductive plate, and the second conductive plate is interposed via the first connecting portion. The first conductive plate is connected to the first conductive plate, the third conductive plate is connected to the first conductive plate through the second connecting portion, and the first weight is connected to the second conductive plate. Preferably, the second weight is fixed to at least one main surface of the third conductor plate.

  Moreover, it is preferable that the support portion of the piezoelectric vibration unit of the present invention is an elastic body.

  The piezoelectric speaker of the present invention includes the piezoelectric vibration unit and a vibration part, and the support part is fixed to the vibration part.

  According to the present invention, a piezoelectric vibration unit and a piezoelectric speaker having excellent propagation efficiency can be obtained.

It is a top view which shows an example of embodiment which concerns on the piezoelectric vibration unit of this invention. It is sectional drawing which shows an example of embodiment which concerns on the piezoelectric speaker at the time of using the piezoelectric vibration unit in FIG. FIG. 6 is another example of the embodiment according to the piezoelectric vibration unit of the present invention, and is a cross-sectional view taken along line AA in FIG. 1. It is sectional drawing explaining the piezoelectric speaker by a prior art.

  Hereinafter, embodiments of the present invention will be described in detail.

(First embodiment)
FIG. 1 is a top view showing an example of an embodiment according to the piezoelectric vibration unit of the present invention. As shown in FIG. 1, the piezoelectric vibration unit 10 of the present invention includes a rectangular first conductor plate 1, a support portion 2, a plate-like piezoelectric element 3, a first connection portion 4, and a second connection portion. The connecting portion 5, the first weight 6, and the second weight 7 are provided.

  The piezoelectric element 3 is fixed to the main surface of the first conductor plate 1, and both end portions in the longitudinal direction of the first conductor plate 1 are supported by the support portions 2. Furthermore, a first connecting portion 4 and a second connecting portion 5 are formed at the center of the two side surfaces parallel to the longitudinal direction of the first conductor plate 1, respectively. One weight 6 is connected, and a second weight 7 is connected to the second connecting portion 5.

  FIG. 2 is a cross-sectional view illustrating an example of an embodiment according to a piezoelectric speaker when the piezoelectric vibration unit in FIG. 1 is used. This sectional view includes a sectional view taken along line BB in FIG. That is, the piezoelectric vibration unit 20 is configured by fixing the support portion 2 of the piezoelectric vibration unit in FIG. 1 to the vibration portion 11 that is an object of vibration (not shown in FIG. 1).

  Since the vibration part 11 in this embodiment uses a housing, the piezoelectric vibration unit 10 is housed in the housing space of the housing.

  When a drive voltage is applied to the piezoelectric element 3, the piezoelectric element 3 expands and contracts and bends, and a force that flexibly vibrates together with the first conductor plate 1 works. The force of this bending vibration is transmitted to the first weight 6 and the second weight 7 via the first connecting portion 4 and the second connecting portion 5, and vibrates the first weight 6 and the second weight 7. Try to let them.

  Further, the central portion of the first conductor plate 1 on which the first connecting portion 4 and the second connecting portion 5 are formed is fixed by the inertial force of the vibration of the first weight 6 and the second weight 7. As is the case, vibration is inhibited. Therefore, the vibration of the first conductor plate 1 works to release force to both end portions in the longitudinal direction, and the vibration at both end portions fixed to the support portion 2 increases.

  With such a configuration, the bending vibration force generated by the expansion and contraction of the piezoelectric element becomes a force having a large amplitude in the support portion, so that the vibration can be efficiently transmitted to the vibration receiving portion to which the support portion is fixed. .

  In addition, since the vibration caused by the first weight and the second weight and the vibration of the piezoelectric element do not interfere with each other, the transmission efficiency of vibration is good.

  Further, in the conventional piezoelectric speaker, the vibration of the piezoelectric element is transmitted from the piezoelectric element to the elastic plate member, the connection portion to the weight, the weight, the connection portion to the weight, the elastic plate member, the coupling portion, and the vibration plate. However, the piezoelectric speaker of the present invention has excellent vibration propagation efficiency because the vibration of the piezoelectric element is directly transmitted from the support portion to the vibration receiving portion.

  In addition, when receiving an impact from the outside such as dropping, the first conductor plate fixed by the support portion 2 has a large amplitude generated in the first weight and the second weight, which are free ends. The vibration is alleviated by the first connecting portion and the second connecting portion, and the piezoelectric element is not greatly bent. Therefore, excessive stress on the piezoelectric element can be suppressed, and damage to the piezoelectric element can be prevented. That is, with such a configuration, a piezoelectric vibration unit having strength against external impact such as dropping can be obtained.

  In order to obtain these effects, the first connecting portion and the second connecting portion are formed from those having elasticity. This elasticity means that the small vibration of the first conductor plate is efficiently transmitted to the first weight and the second weight, and the piezoelectric element is not damaged when subjected to an external impact. It means a degree of elasticity.

  Further, the configuration of the piezoelectric vibration unit of the present invention is such that the first connecting portion 4 is provided on one side surface parallel to the longitudinal direction of the first conductive plate 1, and the first connecting portion 4 has A first weight 6 is connected. Furthermore, a second connecting portion 5 is provided on the other side surface parallel to the longitudinal direction of the first conductor plate 1, and a second weight 7 is connected to the second connecting portion 5. . The piezoelectric element 3 fixed to the first conductor plate 1, the first weight 6 and the second weight 7 are arranged on the same plane via the first connecting portion 4 and the second connecting portion 5. ing. Therefore, a low-profile piezoelectric vibration unit can be obtained.

  In the present embodiment, a configuration is used in which a housing is used for the vibration-receiving portion 11 and the piezoelectric vibration unit is housed in the housing space of the housing, but this is not a limitation. In other words, the piezoelectric vibration unit of the present invention vibrates the vibration part itself to which the support part is fixed, and the vibration part itself becomes a vibration plate. Anything can be used as long as vibration is transmitted.

  In addition, as in the present embodiment, if a sealed housing is used as the shaker and the housing has excellent waterproof properties, it is possible to prevent external moisture from entering the inside of the housing. A piezoelectric speaker having excellent waterproof properties can be obtained.

  In this embodiment, a piezoelectric unimorph is configured by fixing a plate-like piezoelectric element 3 at the center of one main surface of the first conductor plate 1. It may be a configuration. That is, the piezoelectric element 3 may be fixed to each of both main surfaces of the first conductor plate 1.

  The support 2 is preferably an elastic body such as a silicone resin. Since the support portion 2 is made of an elastic body, the Q value of vibration when the piezoelectric element 3 is driven is lowered. After stopping, the response time until the piezoelectric element 3 stops can be shortened.

  If variation occurs in the vibration axis composed of the piezoelectric element and the weight, the sound quality may be deteriorated. In the piezoelectric vibration unit of the present invention, the first weight and the second weight are arranged on both side surfaces parallel to the longitudinal direction of the first conductor plate, respectively, thereby vibrating the first weight and the second weight. Can be balanced, and stable vibration can be obtained. Therefore, deterioration of sound quality is prevented, and excellent sound pressure can be obtained even in the low sound range.

  The first connecting part and the second connecting part may be arranged so that the amplitudes caused by vibrations of the first weight and the second weight connected to each other do not cancel each other. In order to easily balance the vibration of the second weight, it is desirable that the first connecting portion and the second connecting portion are arranged symmetrically about the longitudinal direction of the first conductor plate.

  Further, it is desirable that the first conductor plate is disposed at a position where the amplitude of the first conductor plate is maximized, and the first connecting portion and the second connecting portion are located at positions where vibration is efficiently propagated to the first weight and the second weight. It is desirable to arrange.

  A plurality of connecting portions may be formed on each side surface of the first conductor plate. When configuring a plurality of connecting portions, the formation positions of the connecting portions may be appropriately determined in consideration of vibration propagation efficiency and vibration balance.

  Further, it is desirable that the first connecting portion 4 and the second connecting portion 5 are integrally formed of the same material as the first conductor plate 1.

  FIG. 3 is another example of the embodiment according to the piezoelectric vibration unit of the present invention, and is a cross-sectional view taken along line AA in FIG. As shown in FIG. 3, a rectangular second conductor plate 8 and a third conductor plate 9 are further provided, the first connecting portion 4 and the second conductor plate 8 are connected, and the second connecting portion 5 is connected. And the third conductor plate 9 are connected. A configuration in which the first weight 6 is fixed to the main surface of the second conductor plate 8 and the second weight 7 is fixed to the main surface of the third conductor plate 9 may be employed.

  In the case of the configuration of the present embodiment, the second conductor plate and the third conductor plate may be formed of a different material from the first conductor plate and connected to the first conductor plate. The conductor plate 1, the second conductor plate 8, the third conductor plate 9, the first connecting portion 4, and the second connecting portion 5 may be integrally formed of the same material.

  The material of the first conductor plate, the second conductor plate, the third conductor plate, the first connecting portion, and the second connecting portion takes into account the strength, the difference in thermal expansion coefficient from the piezoelectric element, the Young's modulus, etc. And may be selected as appropriate.

  In addition, the length and thickness of the first conductor plate, the second conductor plate, the third conductor plate, and the piezoelectric element may be appropriately set in consideration of the strength, the magnitude of the amplitude, and the like.

  Further, the material and length of the first weight and the second weight may be designed so that the amplitude in the support portion is increased, and may be appropriately selected according to the specification. Furthermore, since the transmission efficiency of vibration to the support portion can be improved, it is desirable that the mass is heavy.

  As described above, a piezoelectric vibration unit and a piezoelectric speaker having excellent propagation efficiency to a vibration object can be obtained.

  As mentioned above, although the Example of this invention was described, this invention is not limited above, The change and correction of a structure are possible in the range which does not deviate from the summary of this invention. That is, it is a matter of course that various modifications and corrections that can be made by those skilled in the art are also included in the present invention.

DESCRIPTION OF SYMBOLS 1 1st conductor plate 2, 33 Support part 3, 32 Piezoelectric element 4 1st connection part 5 2nd connection part 6 1st weight 7 2nd weight 8 2nd conductor plate 9 3rd conductor plate DESCRIPTION OF SYMBOLS 10 Piezoelectric vibration unit 11 Vibrated part 20, 30 Piezoelectric speaker 31 Elastic board material 34 Weight 35 Base part 36 Connection part 37 Diaphragm

Claims (6)

A rectangular first conductive plate;
A support portion for supporting both longitudinal ends of the first conductor plate;
A plate-like piezoelectric element fixed to at least one main surface of the first conductor plate;
A first connecting portion formed on at least a part of one side surface parallel to the longitudinal direction of the first conductor plate;
A second connecting portion formed on at least a part of the other side surface parallel to the longitudinal direction of the first conductor plate;
A first weight connected to the first coupling portion;
A piezoelectric vibration unit comprising: a second weight connected to the second connecting portion.   2. The piezoelectric vibration unit according to claim 1, wherein the first connecting portion and the second connecting portion are arranged symmetrically about the longitudinal direction of the first conductive plate. . The first conductor plate is bent by the bending vibration of the piezoelectric element,
3. The piezoelectric vibration unit according to claim 2, wherein the first connecting portion and the second connecting portion are formed at positions where the amplitude of the first conductor plate is maximized. A rectangular second conductor plate and a rectangular third conductor plate;
The second conductor plate is connected to the first conductor plate via the first connecting portion,
The third conductive plate is connected to the first conductive plate via the second connecting portion,
The first weight is fixed to at least one main surface of the second conductor plate,
The piezoelectric vibration unit according to claim 1, wherein the second weight is fixed to at least one main surface of the third conductor plate.   The piezoelectric vibration unit according to claim 1, wherein the support portion is an elastic body. A piezoelectric vibration unit according to any one of claims 1 to 5 and a portion to be vibrated,
The piezoelectric speaker is characterized in that the support portion is fixed to the shaken portion.

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