JP2015115629A - Speaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a speaker capable of facilitating the adjustment of sound quality.SOLUTION: A speaker 1 includes a laminated piezoelectric actuator 2 to be extended/contracted in a longitudinal direction according to an applied voltage. One end of the laminated piezoelectric actuator 2 in the longitudinal direction comes in contact with the main surface of a base member 4 and the other end comes in contact with the main surface of a diaphragm 3. An area where the laminated piezoelectric actuator 2 comes in contact with the diaphragm 3 is a small area, to thereby heighten a degree of freedom in arranging the laminated piezoelectric actuator 2 with respect to the diaphragm 3. Thus, the adjustment of the sound quality of the speaker 1 is facilitated by changing the position of the laminated piezoelectric actuator 2 with respect to the diaphragm 3.

Description

  The present invention relates to a speaker that generates sound.

  Generally, in a speaker, a sound signal is generated when a voice signal is given to a voice coil arranged in the vicinity of a permanent magnet, and a diaphragm connected to the voice coil vibrates. As described above, a general speaker includes a permanent magnet. However, the permanent magnet is relatively heavy, and a rare earth such as neodymium is used for the permanent magnet. For this reason, in recent years, a speaker that does not use a permanent magnet has been desired.

  As such a speaker not using a permanent magnet, a piezoelectric speaker using a piezoelectric element (piezo element) has been conventionally known (see, for example, Patent Document 1). FIG. 16 is a diagram showing a main structure of a general piezoelectric speaker 91. As shown in FIG. 16, the piezoelectric speaker 91 has a structure in which a relatively thin plate-like piezoelectric element portion 92 is attached to a diaphragm 93 with an adhesive or the like. The piezoelectric element portion 92 includes a monomorph type having a structure using one piezoelectric element and a bimorph type having a structure in which two piezoelectric elements are bonded together.

Japanese Utility Model Publication No. 4-119200

  By the way, the general piezoelectric speaker 91 as described above has a structure in which the piezoelectric element portion 92 is attached to the vibration plate 93, so that there are few portions where the vibration plate 93 vibrates freely. It is easy to promote resonance. Therefore, in general, the piezoelectric speaker 91 does not have sound quality (frequency characteristics) desirable as a speaker. In addition, since the piezoelectric speaker 91 has a low degree of freedom in arranging the piezoelectric element portion 92 with respect to the diaphragm 93, it is difficult to adjust the sound quality by changing the arrangement of the diaphragm 93 and the piezoelectric element portion 92.

  For this reason, a speaker that does not use a permanent magnet and can easily adjust the sound quality has been desired.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a speaker capable of easily adjusting sound quality.

  In order to solve the above-mentioned problem, the invention of claim 1 is a speaker, which is disposed between a base member, a vibration plate that vibrates to generate sound, and the base member and the vibration plate. A laminated piezoelectric actuator that expands and contracts in the longitudinal direction according to the applied voltage, wherein the laminated piezoelectric actuator has one end in the longitudinal direction in contact with the base member and the other end in contact with the diaphragm. The diaphragm is vibrated by expanding and contracting in the direction.

  According to a second aspect of the present invention, in the speaker according to the first aspect, the diaphragm includes a plurality of plate materials made of different materials.

  According to a third aspect of the present invention, in the loudspeaker according to the first or second aspect, a coupling member that couples the base member and the diaphragm with one end fixed to the base member and the other end fixed to the diaphragm. , Is further provided.

  According to a fourth aspect of the present invention, there is provided the speaker according to the first or second aspect, wherein the first protruding portion having a cylindrical shape is provided so as to protrude from the base member toward the diaphragm, and has a first thread. And a cylindrical second projecting portion provided to project from the diaphragm toward the base member and having a second thread formed thereon, the first thread and the second thread. By engaging the base member, the base member and the diaphragm are coupled.

  According to a fifth aspect of the present invention, in the loudspeaker according to the first or second aspect, a cylindrical first protruding portion that is provided to protrude from the base member toward the diaphragm and has a first screw thread. And a cylindrical second projecting portion provided to project from the diaphragm toward the base member and having a second thread formed thereon, and a cylindrical member having a third thread formed, The base member and the diaphragm are coupled by engaging the third thread with both the first and second threads.

  According to the first to fifth aspects of the present invention, since the laminated piezoelectric actuator comes into contact with the diaphragm at the end in the longitudinal direction, the degree of freedom in arranging the laminated piezoelectric actuator with respect to the diaphragm is high. For this reason, the sound quality adjustment of the speaker can be easily performed by changing the position of the laminated piezoelectric actuator.

  In particular, according to the invention of claim 2, since the diaphragm includes a plurality of plate materials made of different materials, the peak and dip of the frequency characteristic of the speaker can be suppressed. In addition, the sound quality of the speaker can be easily adjusted by changing the material of the plate material.

  In particular, according to the invention of claim 3, since the coupling member couples the base member and the diaphragm, the strength of the speaker can be increased. In addition, the sound quality of the speaker can be easily adjusted by changing the specification of the coupling member.

  In particular, according to the invention of claim 4, the speaker can be easily assembled.

  In particular, according to the invention of claim 5, the speaker can be easily assembled.

FIG. 1 is a perspective view showing a configuration of a speaker. FIG. 2 is a cross-sectional view showing a cross section of the speaker according to the first embodiment. FIG. 3 is a diagram showing a basic structure of the laminated piezoelectric actuator. FIG. 4 is a cross-sectional view showing a cross section of the speaker of the second embodiment. FIG. 5 is a cross-sectional view showing a cross section of the speaker of the third embodiment. FIG. 6 is a cross-sectional view showing a cross section of the speaker of the fourth embodiment. FIG. 7 is an exploded view of the speaker of the fourth embodiment. FIG. 8 is a cross-sectional view showing a cross section of the speaker of the fifth embodiment. FIG. 9 is an exploded view of the speaker of the fifth embodiment. FIG. 10 is a diagram illustrating an example of the configuration of a speaker. FIG. 11 is a diagram illustrating an example of a speaker including a protection member. FIG. 12 is a diagram illustrating an example of a speaker including a protection member. FIG. 13 is a diagram illustrating an example of a speaker including a cone-shaped diaphragm. FIG. 14 is a diagram illustrating an example of a speaker including a dome-shaped diaphragm. FIG. 15 is a diagram illustrating an example of a speaker including a composite diaphragm. FIG. 16 is a diagram showing a main structure of a general piezoelectric speaker.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<1. First Embodiment>
FIG. 1 is a perspective view showing the configuration of the speaker 1 according to the first embodiment. FIG. 2 is a cross-sectional view showing a cross section of the speaker 1. In the following description, for convenience of explanation, a direction along the top and bottom of the cross-sectional view is referred to as “vertical direction”, and a direction along the left and right of the cross-sectional view is referred to as “horizontal direction”. Note that the terms indicating these directions are merely for convenience. When the speaker 1 is actually placed on the placement target, the “vertical direction” described below does not need to be along the actual vertical direction. The “horizontal direction” need not be along the actual horizontal direction.

  As shown in FIGS. 1 and 2, the speaker 1 mainly includes a base member 4, a diaphragm 3, and a laminated piezoelectric actuator 2.

  The base member 4 is a plate-like member having a substantially circular main surface and serves as a reference member. The base member 4 is fixed to the placement target of the speaker 1. For example, when the speaker 1 is arranged with an instrument panel in a vehicle compartment of the vehicle as an object to be arranged, the base member 4 is fixed to the instrument panel. In this description, the main surface of the base member 4 is along the horizontal direction.

  The diaphragm 3 is a plate-like member that generates sound by vibration. The diaphragm 3 has a substantially circular main surface, and is arranged on the upper side of the base member 4 so that the main surface is along the horizontal direction. Therefore, the main surface of the diaphragm 3 and the main surface of the base member 4 face each other and are arranged substantially in parallel.

  The diaphragm 3 is configured by overlapping two plate members 31 and 32. The two plate members 31 and 32 included in the diaphragm 3 are different from each other. Examples of the material of the plate materials 31 and 32 include metals such as aluminum, iron and copper, resins such as ABS resin, acrylic resin and polycarbonate, paper and wood.

  It is desirable that the two plate members 31 and 32 included in the diaphragm 3 have greatly different resonance frequencies. For this reason, when one of the two plate members 31 and 32 is a metal, the other is desirably made of a material other than metal (such as a resin). Of course, if the materials are different from each other, both of the two plate materials 31 and 32 may be made of metal, or both may be made of resin.

  The laminated piezoelectric actuator 2 is an actuator that expands and contracts in the longitudinal direction in accordance with a given voltage. Such a laminated piezoelectric actuator has characteristics such as high response to signals, high accuracy of displacement, and low power consumption. Hereinafter, the laminated piezoelectric actuator 2 is simply referred to as “actuator 2”.

  FIG. 3 is a diagram showing a basic structure of the actuator 2. As shown in FIG. 3, the actuator 2 is formed by stacking, for example, a plurality of 100 to 200 piezoelectric elements (piezo elements) 21 into a rod shape. An electrode is disposed on each of the plurality of piezoelectric elements 21. When a signal whose voltage fluctuates is applied to the electrode, the actuator 2 linearly expands and contracts (displaces) in the longitudinal direction (the direction of the arrow A1 in the figure) that is the stacking direction of the piezoelectric elements 21 in response to the signal. To do.

  As shown in FIGS. 1 and 2, the actuator 2 is disposed between the main surface of the base member 4 and the main surface of the diaphragm 3. The actuator 2 is arranged such that its longitudinal direction is along the vertical direction. Therefore, the longitudinal direction of the actuator 2 is substantially orthogonal to the main surface of the base member 4 and the main surface of the diaphragm 3.

  One end in the longitudinal direction of the actuator 2 is in contact with the main surface of the base member 4, and the other end in the longitudinal direction of the actuator 2 is in contact with the main surface of the diaphragm 3. Therefore, when an audio signal whose voltage varies is applied, the actuator 2 expands and contracts according to the audio signal, and vibrates the diaphragm 3 that is in contact therewith. As a result, sound is generated from the diaphragm 3. For this reason, the speaker 1 can generate sound without using a permanent magnet.

  Further, as shown in the figure, a plurality of support columns 5 extending in the vertical direction are provided between the base member 4 and the diaphragm 3. The base member 4 and the diaphragm 3 are coupled via the plurality of support columns 5 serving as coupling members. The lower end of each column 5 is fixed to the base member 4 in contact with the main surface of the base member 4, and the upper end of each column 5 is fixed to the diaphragm 3 in contact with the main surface of the diaphragm 3.

  A female screw 5 b that engages with the male screw 62 is formed at the lower end of each column 5, and a female screw 5 a that engages with the male screw 61 is formed at the upper end of each column 5. The male screw 62 is inserted from the lower part of the base member 4 and engages with the female screw 5 b at the lower end of the column 5 to fix the lower end of the column 5 to the base member 4. On the other hand, the male screw 61 is inserted from the upper part of the diaphragm 3 and engages with the female screw 5 a at the upper end of the support column 5 to fix the upper end of the support column 5 to the diaphragm 3. Thus, since the support | pillar 5 couple | bonds the base member 4 and the diaphragm 3, the intensity | strength as the speaker 1 can be raised.

  The vertical length of each column 5 is shorter than the length in the longitudinal direction when the actuator 2 contracts most. For this reason, the actuator 2 is sandwiched and fixed between the main surface of the base member 4 and the main surface of the diaphragm 3.

  As a result, the end of the actuator 2 in the longitudinal direction directly contacts the main surface of the base member 4 and the main surface of the diaphragm 3 without using a material that absorbs vibration such as an adhesive. For this reason, the expansion and contraction of the actuator 2 can be transmitted directly to the diaphragm 3. As a result, the waveform of the audio signal can be faithfully reflected in the vibration of the diaphragm 3, and distortion and noise can be made difficult to occur in the sound generated by the diaphragm 3.

  As described above, the speaker 1 of the present embodiment includes the actuator (multilayer piezoelectric actuator) 2 that expands and contracts in the longitudinal direction according to the applied voltage. One end of the actuator 2 in the longitudinal direction contacts the main surface of the base member 4, and the other end contacts the main surface of the diaphragm 3. The position of the actuator 2 may be the center of the diaphragm 3 or a position deviated from the center of the diaphragm 3. Since the area where the actuator 2 contacts the diaphragm 3 is small, the degree of freedom of arrangement of the actuator 2 with respect to the diaphragm 3 is high. For this reason, in the development process, the sound quality of the speaker 1 can be easily adjusted by variously changing the position of the actuator 2 with respect to the diaphragm 3. As a result, the frequency characteristic of the speaker 1 can be changed to a desirable frequency characteristic according to the purpose of use of the speaker 1. In general, the frequency characteristics of the speaker 1 can be made flat when the actuator 2 is arranged at a position off the center of the diaphragm 3.

  Moreover, since the diaphragm 3 includes two plate materials 31 and 32 of different materials, even if one plate material resonates, the other plate material suppresses the resonance. For this reason, the peak and dip of the frequency characteristic of the speaker 1 can be suppressed, and the frequency characteristic of the speaker 1 can be changed to a flat frequency characteristic. Further, in the development process, the sound quality of the speaker 1 can be easily adjusted by variously changing the combination of the two plate members 31 and 32.

  In the development process, the material of the base member 4 can also be changed. Further, in the development process, the specifications (number, material, position, etc.) of the support columns 5 that are connecting members for connecting the base member 4 and the diaphragm 3 can be changed. As described above, the sound quality of the speaker 1 can be easily adjusted by changing the material of the base member 4 and the specifications of the support column 5 in various ways. As materials for the base member 4 and the support column 5, metals such as aluminum, iron, and copper, and resins such as ABS resin, acrylic resin, and polycarbonate can be considered.

<2. Other embodiments>
Further, the sound quality adjustment of the speaker 1 can also be performed by setting the aspect in which the base member 4 and the diaphragm 3 are combined to an aspect different from that of the first embodiment. In the following, another embodiment in which the aspect of coupling the base member 4 and the diaphragm 3 is different will be described. Since the main configuration of the speaker 1 of the other embodiment is substantially the same as that of the first embodiment, the following description will focus on differences from the first embodiment.

<2-1. Second Embodiment>
First, a second embodiment will be described. FIG. 4 is a cross-sectional view showing a cross section of the speaker 1 according to the second embodiment.

  In the speaker 1 of the second embodiment, the length of the male screw 61 is longer than that of the first embodiment. Further, each of the plurality of columns 5 serving as a coupling member has a cylindrical shape and has a hollow inner hole 5c. Further, a female screw 4 a is formed at a contact portion of the base member 4 with each column 5.

  The male screw 61 is inserted from above the diaphragm 3, passes through the inner hole 5 c of the support column 5, and engages with the female screw 4 a of the base member 4. Thereby, the lower end of each support column 5 is fixed to the base member 4 and the upper end is fixed to the diaphragm 3, and the base member 4 and the diaphragm 3 are coupled via the plurality of columns 5.

  As described above, in the speaker 1 according to the second embodiment, since the column 5 is fixed to both the base member 4 and the diaphragm 3 by one male screw 61, the number of components as the speaker 1 can be reduced.

  In addition, a thread may be formed in the inner hole 5c of the column 5 so that the column 5 functions as a female screw that engages with the male screw 61. In contrast to the above, the diaphragm 3 may be formed with a female screw that engages with the male screw. In this case, the male screw is inserted from the lower part of the base member 4, passes through the inner hole 5 c of the support column 5, and engages with the female screw of the diaphragm 3.

<2-2. Third Embodiment>
Next, a third embodiment will be described. FIG. 5 is a sectional view showing a section of the speaker 1 according to the third embodiment.

  In the speaker 1 according to the third embodiment, a plurality of support columns 41 and a base member 4 serving as coupling members are formed of a single member and integrated. Thereby, the lower end of each column 41 is fixed to the base member 4.

  A female screw 41 a is formed at the upper end of each column 41. The male screw 61 is inserted from the upper part of the diaphragm 3 and engages with the female screw 41 a at the upper end of the support column 41 to fix the upper end of the support column 41 to the diaphragm 3. As a result, the base member 4 and the diaphragm 3 are coupled via the plurality of support columns 41.

  Thus, in the speaker 1 of the third embodiment, the base member 4 and the plurality of support columns 41 are integrated. Since the male screw 61 is used only for fixing the upper end of each column 41, the number of components as the speaker 1 can be reduced. Contrary to the above, the lower plate member 32 of the diaphragm 3 and the plurality of support columns may be integrated with a single member, and the male screw may be used only for fixing the lower end of each support column. Good.

<2-3. Fourth Embodiment>
Next, a fourth embodiment will be described. FIG. 6 is a cross-sectional view showing a cross section of the speaker 1 according to the fourth embodiment. In the speaker 1 of the fourth embodiment, the base member 4 and the diaphragm 3 are coupled without using male screws 61 and 62 as independent components.

  FIG. 7 is an exploded view (sectional view) of the speaker 1 according to the fourth embodiment. In the speaker 1 according to the fourth embodiment, the base member 4 is provided with a first protrusion 42 so as to protrude upward (from the diaphragm 3 side) from the main surface of the base member 4. The first protrusion 42 has a hollow cylindrical shape with a circular cross section viewed from the top and bottom.

  The base member 4 and the first projecting portion 42 are constituted by a single member and integrated. Thereby, the lower end of the first protrusion 42 is fixed to the base member 4. A thread 42a is formed on the inner periphery of the first protrusion 42, and the first protrusion 42 functions as a female screw as a whole.

  Further, a second projecting portion 33 is provided in the diaphragm 3 so as to project downward from the main surface of the diaphragm 3 (on the base member 4 side). The second protrusion 33 also has a hollow cylindrical shape with a circular cross section viewed from the top-bottom direction.

  The lower plate member 32 and the second projecting portion 33 of the diaphragm 3 are formed of a single member and integrated. As a result, the upper end of the second protrusion 33 is fixed to the diaphragm 3. The diameter of the outer periphery of the second protrusion 33 is substantially the same as the diameter of the inner periphery of the first protrusion 42. A thread 33a is formed on the outer periphery of the second protrusion 33, and the second protrusion 33 functions as a male screw as a whole.

  When assembling the speaker 1 according to the fourth embodiment, the actuator 2 is disposed between the base member 4 and the diaphragm 3, and the diaphragm 3 is brought into contact with the base member 4 from above. Then, the diaphragm 3 is rotated in a predetermined direction relative to the base member 4 around an axis along the vertical direction.

  Thereby, as shown in FIG. 6, the thread 33a of the 2nd protrusion part 33 as an external thread engages with the thread 42a of the 1st protrusion part 42 as an internal thread. As a result, the first projecting portion 42 and the second projecting portion 33 become a coupling member, and the base member 4 and the diaphragm 3 are coupled. The actuator 2 is sandwiched and fixed between the main surface of the base member 4 and the main surface of the diaphragm 3.

  As described above, in the speaker 1 according to the fourth embodiment, the base member 4 and the diaphragm 3 can be coupled without using the male screws 61 and 62 as independent components, so that the speaker 1 can be easily assembled. . Contrary to the above, the first protrusion 42 may function as a male screw and the second protrusion 33 may function as a female screw.

<2-4. Fifth embodiment>
Next, a fifth embodiment will be described. FIG. 8 is a cross-sectional view showing a cross section of the speaker 1 according to the fifth embodiment. In the speaker 1 of the fifth embodiment, the base member 4 and the diaphragm 3 are coupled without using male screws 61 and 62 as independent parts.

  FIG. 9 is an exploded view (sectional view) of the speaker 1 according to the fifth embodiment. In the speaker 1 of the fifth embodiment, the first protrusion 43 is provided in the base member 4 so as to protrude upward (from the diaphragm 3 side) from the main surface of the base member 4. The first protrusion 43 has a hollow cylindrical shape with a circular cross section viewed from the top-bottom direction.

  The base member 4 and the first projecting portion 43 are constituted by a single member and integrated. Thereby, the lower end of the first protrusion 43 is fixed to the base member 4. A thread 43a is formed on the inner periphery of the first protrusion 43, and the first protrusion 43 functions as a female screw as a whole.

  Further, a second projecting portion 34 is provided in the diaphragm 3 so as to project downward from the main surface of the diaphragm 3 (on the base member 4 side). The second protrusion 34 also has a hollow cylindrical shape with a circular cross section viewed from the top and bottom.

  The lower plate member 32 and the second projecting portion 34 of the diaphragm 3 are formed of a single member and integrated. Thereby, the upper end of the second protrusion 34 is fixed to the diaphragm 3. The diameter of the inner periphery of the second protrusion 34 substantially matches the diameter of the inner periphery of the first protrusion 42. A screw thread 34a is formed on the inner periphery of the second protrusion 34, and the second protrusion 34 also functions as a female screw as a whole.

  The speaker 1 according to the fifth embodiment includes a spacer 7 that is a hollow cylindrical member having a circular cross section viewed from the top and bottom. The upper and lower ends of the spacer 7 are open. The outer diameter of the spacer 7 is substantially the same as the inner diameter of the first protrusion 42 and the second protrusion 34. A thread 7a is formed on the outer periphery of the spacer 7, and the spacer 7 functions as a male screw as a whole. As the material of the spacer 7, a metal such as aluminum, iron, or copper, and a resin such as ABS resin, acrylic resin, or polycarbonate can be considered.

  When assembling the speaker 1 of the fifth embodiment, the actuator 2 is disposed inside the spacer 7, the base member 4 is brought into contact with the spacer 7 from the lower side, and the diaphragm 3 is brought into contact with the spacer 7 from the upper side. Let Then, the base member 4 and the diaphragm 3 are rotated in a predetermined direction relative to the spacer 7 around an axis extending in the vertical direction.

  As a result, as shown in FIG. 8, the spacer 43 as the male screw is provided on both the screw thread 43a of the first protruding portion 43 as the female screw and the screw thread 34a of the second protruding portion 34 as the female screw. The thread 7a engages. As a result, the first projecting portion 43, the second projecting portion 34, and the spacer 7 become a coupling member, and the base member 4 and the diaphragm 3 are coupled. The actuator 2 is sandwiched and fixed between the main surface of the base member 4 and the main surface of the diaphragm 3 while being enclosed in the spacer 7.

  As described above, in the speaker 1 according to the fifth embodiment, the base member 4 and the diaphragm 3 can be coupled without using the male screws 61 and 62 as independent components, so that the speaker 1 can be easily assembled. . Contrary to the above, the first protrusion 43 and the second protrusion 34 may function as male screws, and the spacer 7 may function as a female screw.

<3. Modification>
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications are possible. Below, such a modification is demonstrated. All the forms including the above-described embodiment and the form described below can be appropriately combined.

  In the above embodiment, the speaker 1 includes the coupling member such as the support column 5, and the base member 4 and the diaphragm 3 are coupled via the coupling member. On the other hand, as shown in FIG. 10, the speaker 1 may not include the coupling member. Even in this case, it is desirable that the end portion of the actuator 2 is in direct contact with the main surface of the base member 4 and the main surface of the diaphragm 3 without using an adhesive that absorbs vibration. Therefore, in this case, for example, as shown in FIG. 10, the adhesive B is attached to the outer periphery of the end portion of the actuator 2, thereby connecting the end portion of the actuator 2 and the main surface of the base member 4 and the diaphragm 3. It is desirable to join.

  The speaker 1 may include a protective member that protects the diaphragm 3. FIG.11 and FIG.12 has shown an example of the speaker 1 provided with the grille 8 used as a protection member. The grill 8 is disposed so as to cover the upper portion of the diaphragm 3 in order to prevent contact between the diaphragm 3 and the foreign matter. The grill 8 is fixed to the support column 5 together with the diaphragm 3 by, for example, a male screw 61.

  In the above embodiment, the base member 4 fixed to the arrangement target is described as a plate-like member. However, the base member 4 is a plate-like member if it has a main surface facing the diaphragm 3. It does not have to be.

  Moreover, in the said embodiment, although the diaphragm 3 was comprised with the two board | plate materials 31 and 32, you may comprise with one board | plate material. Conversely, the diaphragm 3 may be composed of three or more plate materials. When the diaphragm 3 includes three or more plate materials, it is desirable that the materials of the three or more plate materials are different from each other. Moreover, in the said embodiment, although the shape of the main surface of the diaphragm 3 was substantially circular, other shapes, such as an ellipse and a rectangle, may be sufficient.

  Moreover, in the said embodiment, although the diaphragm 3 comprised by the plane plate material was employ | adopted, you may employ | adopt another type of diaphragm. For example, as shown in FIG. 13, a cone-shaped diaphragm 33 may be employed. In this case, one end of the actuator 2 in the longitudinal direction comes into contact with the center portion of the diaphragm 33, and the actuator 2 expands and contracts in the longitudinal direction to vibrate the diaphragm 33. Further, as shown in FIG. 14, a dome-shaped diaphragm 34 may be employed. In this case, one end of the actuator 2 in the longitudinal direction comes into contact with the central portion of the diaphragm 34, and the actuator 2 expands and contracts in the longitudinal direction to vibrate the diaphragm 34.

  Moreover, you may employ | adopt the composite type diaphragm which combined the diaphragm from which a type differs. For example, as shown in FIG. 15, a vibration plate 35 in which a vibration plate 36 made of a flat plate material and a dome-shaped vibration plate 37 are combined in an overlapping manner can be employed. Since the frequency characteristics differ greatly between different types of diaphragms, the frequency characteristics of the speaker 1 can be made flat frequency characteristics by adopting such a composite diaphragm.

1 Speaker 2 Actuator 3 Diaphragm 4 Base Member 5 Post 7 Spacer

Claims (5)

A speaker,
A base member;
A diaphragm that vibrates and generates sound;
A laminated piezoelectric actuator which is disposed between the base member and the diaphragm and expands and contracts in the longitudinal direction in accordance with a given voltage;
With
The speaker is characterized in that the laminated piezoelectric actuator has one end in the longitudinal direction in contact with the base member and the other end in contact with the diaphragm, and vibrates the diaphragm by expanding and contracting in the longitudinal direction. The speaker according to claim 1,
The speaker includes a plurality of plates made of different materials. The speaker according to claim 1 or 2,
One end is the base member, the other end is fixed to the diaphragm, and a coupling member that couples the base member and the diaphragm;
The speaker further comprising: The speaker according to claim 1 or 2,
A cylindrical first protrusion provided to protrude from the base member toward the diaphragm and having a first thread;
A cylindrical second protrusion provided to protrude from the diaphragm toward the base member and having a second thread;
Further comprising
The speaker according to claim 1, wherein the base member and the diaphragm are coupled by engaging the first thread and the second thread. The speaker according to claim 1 or 2,
A cylindrical first protrusion provided to protrude from the base member toward the diaphragm and having a first thread;
A cylindrical second protrusion provided to protrude from the diaphragm toward the base member and having a second thread;
A cylindrical member in which a third thread is formed;
Further comprising
The speaker, wherein the base member and the diaphragm are coupled by engaging the third screw thread with both the first and second screw threads.

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