WO2013002042A1

WO2013002042A1 - Piezoelectric vibration element

Info

Publication number: WO2013002042A1
Application number: PCT/JP2012/065329
Authority: WO
Inventors: 哲司横江; 清有沢; 忠男砂原; 修川崎
Original assignee: 北陸電気工業株式会社
Priority date: 2011-06-27
Filing date: 2012-06-15
Publication date: 2013-01-03
Also published as: CN103621112A; JPWO2013002042A1; CN103621112B; JP5953304B2

Abstract

Provided is a piezoelectric vibration element that can obtain a vibration that is larger than conventional vibrations. A pair of extensions to which piezoelectric elements are not joined are formed at both ends in the lengthwise direction of a vibrating plate. A pair of support sections that support the pair of extensions of the vibrating plate are formed in a support body. The support sections have a pair of contact pieces that contact the front surface and back surface of the extensions and support the extensions in a manner so as to allow that extensions to oscillate centered at the section of contact with the pair of contact pieces when the piezoelectric element is expanding and contracting.

Description

Piezoelectric vibration element

The present invention relates to a piezoelectric vibration element.

Japanese Patent Application Laid-Open No. 2000-305573 (Patent Document 1) includes a piezoelectric vibrating body including a thin plate-like diaphragm and a piezoelectric element attached to the diaphragm, and a housing and a cover member that support the piezoelectric vibrating body. A piezoelectric vibration element used for a piezoelectric pump is disclosed. The piezoelectric vibrating body of Patent Document 1 is supported by a housing and a cover member with both ends inserted into a space having a substantially U-shaped cross section formed by a housing and a cover member.

JP 2000-305573 A

In the conventional structure for supporting a piezoelectric vibration element shown in Patent Document 1, both ends of a piezoelectric vibrating body are inserted into a substantially U-shaped space formed by a housing and a cover member to support both ends. is doing. In such a support structure of the piezoelectric vibration element, both end portions of the piezoelectric vibration member are substantially fixed. For this reason, both end portions of the piezoelectric vibrating body are hardly deformed, so that the vibration of the piezoelectric vibrating body is obstructed and the vibration of the piezoelectric vibrating body cannot be increased. For this reason, conventionally, applications that can use a piezoelectric vibration element as a vibration source have been limited.

An object of the present invention is to provide a piezoelectric vibration element capable of obtaining a greater vibration than before.

The present invention provides a piezoelectric vibration element including a piezoelectric vibration member in which one or more piezoelectric elements are bonded to at least one of a front surface and a back surface of an elongated vibration plate, and a support body that supports the piezoelectric vibration member so as to vibrate. Subject to improvement. The diaphragm of the piezoelectric vibrating body includes a pair of extensions that are not joined with piezoelectric elements at both ends in the longitudinal direction. The support body includes a pair of support portions that support the diaphragm. The pair of support portions each have a pair of contact pieces that contact the front and back surfaces of the extension portion, and the extension portion swings around the contact portion with the pair of contact pieces when the piezoelectric element is expanded and contracted. It has a structure that supports the extension so as to allow movement. In the present specification, “the extension portion swings around the contact portion with the pair of contact pieces” means that the contact points at the two points of the front and back surfaces of the extension portion and the pair of contact pieces are extended. It means that it becomes the center of oscillation of the front and back surfaces of the part.

According to the present invention, since the both ends of the diaphragm to which the piezoelectric element of the piezoelectric vibrating body is joined are supported by the pair of support portions, the expansion and contraction of the piezoelectric element is not restricted. In addition, since both ends of the diaphragm are supported in a state where they can swing around the contact portion with the pair of contact pieces, the movement of the diaphragm when the piezoelectric element expands and contracts is almost restricted. There is no. As a result, it is possible to make maximum use of the vibration generated in the piezoelectric vibrating body, and the application as a vibration source of the piezoelectric vibration element can be expanded.

Piezoelectric elements may be provided on the front and back surfaces of the diaphragm. If comprised in this way, since the piezoelectric element provided in the surface and back surface of a diaphragm can be used as a vibration generation source, it becomes possible to enlarge the vibration of a piezoelectric type vibration element.

It is preferable that the pair of contact pieces of the support portion is configured by a curved surface in which a contact surface in contact with the front surface or the back surface of the extension portion is convex toward the extension portion of the diaphragm. By configuring the pair of contact pieces in this way, the contact area between the pair of contact pieces and the front surface or the back surface of the extension portion can be reduced, and stress is not concentrated on the contact portion. As a result, the restraint area of the extension portion by the pair of contact pieces is reduced, and the contact resistance between the pair of contact pieces and the extension portion of the diaphragm is reduced, so that the movement of both ends of the diaphragm is smoothed, The vibration of the piezoelectric vibration element can be further increased.

It should be noted that the pair of contact pieces are preferably configured to face each other through the extension. If comprised in this way, it will become possible to ensure the rocking | fluctuation range of an extension part to the maximum.

As a specific configuration of the support body, it is assumed that a main body portion extending in the longitudinal direction with a predetermined interval between the piezoelectric vibrator and a rising portion rising from both longitudinal ends of the main body portion is provided. Can do. In this case, a support part is provided at the tip of the rising part. When the support is configured in this manner, the main body can be used as a fixing portion for the entire piezoelectric vibration element, and the attachment of the piezoelectric vibration element is facilitated.

The support can be formed integrally by bending a single metal plate. If comprised in this way, the number of parts at the time of manufacturing a piezoelectric vibration element can be reduced, and a piezoelectric vibration element can be manufactured cheaply.

When it is desired to further increase the vibration of the piezoelectric vibration element, a weight member may be attached to the piezoelectric vibrating body so as not to inhibit expansion and contraction of the piezoelectric vibrating body. When such a weight member is attached, the inertia force of the piezoelectric diaphragm is increased by the weight member, and the amplitude can be increased. The weight member is preferably provided at the center in the longitudinal direction of the piezoelectric vibrating body where the amplitude of vibration is the largest.

The weight member can be attached to the piezoelectric vibrator by, for example, a sandwiching portion that sandwiches the piezoelectric vibrator in the thickness direction. If comprised in this way, since a weight member and a piezoelectric vibrating body will not be in a completely fixed state, it can suppress that presence of a weight member becomes a factor which inhibits a deformation | transformation of a piezoelectric vibrating body.

The weight member has a structure in which a pair of weight pieces, which are located on both sides in the thickness direction of the piezoelectric vibrating body and have a shape in which a gap between the piezoelectric vibrating body is widened toward the pair of extending portions, are integrated with the connecting portion. be able to. If the weight member is configured in this manner, the weight member does not interfere with the deformation of the piezoelectric vibrating body.

The weight member may be configured to have a weight piece only on the surface side not facing the support of the piezoelectric vibrator. In this case, the weight member is located on one side in the thickness direction of the piezoelectric vibrating body and has a weight piece having a shape in which a distance between the piezoelectric vibrating body is widened toward the pair of extension portions, and a supporting body of the piezoelectric vibrating body. A sandwiching piece that is in contact with the central portion of the surface that does not face the main body is connected by a connecting portion to be integrated. In this case, since there is no weight piece between the support body and the diaphragm, the weight piece positioned between the support body and the diaphragm comes into contact with the support body due to the deformation of the vibration plate and vibrates. The deformation of the plate is not limited. Therefore, a desired magnitude of vibration can be reliably obtained.

1 is a front view of a piezoelectric vibration element according to an embodiment of the present invention. FIG. 2 is a bottom view of the piezoelectric vibration element shown in FIG. 1. FIG. 2 is a rear view of the piezoelectric vibration element shown in FIG. 1. It is an enlarged view of a 1st support part. It is a figure which shows the modification of a support part. It is a rear view of the piezoelectric type vibration element of other embodiment of this invention.

Hereinafter, an example of an embodiment of a piezoelectric vibration element of the present invention will be described with reference to the drawings. FIG. 1 shows a front view of a piezoelectric vibration element of the present embodiment that can be used as a vibrator incorporated in a mobile phone, for example. 2 and 3 respectively show a bottom view and a rear view of the piezoelectric vibration element shown in FIG. In FIG. 1 to FIG. 3, some thickness dimensions are exaggerated for easy understanding. The piezoelectric vibration element 1 according to the present embodiment includes a piezoelectric vibrating body 3, a weight member 5 attached to the piezoelectric vibrating body 3, and a support body 7 that supports the piezoelectric vibrating body 3.

The piezoelectric vibrating body 3 includes a vibration plate 9, a first piezoelectric element 11 and a second piezoelectric element 13 joined to the vibration plate 9. The diaphragm 9 has an elongated rectangular plate shape having a front surface 9a and a back surface 9b, and is formed of a metal plate made of iron-nickel alloy (42 alloy), brass or the like. In the present embodiment, the first piezoelectric element 11 is bonded to the front surface 9a of the diaphragm 9, and the second piezoelectric element 13 is bonded to the back surface 9b. Accordingly, the piezoelectric vibration element of the present embodiment is a bimorph type piezoelectric vibration element.

The first piezoelectric element 11 and the second piezoelectric element 13 are joined to the front surface 9a and the rear surface 9b of the vibration plate 9 so as to leave a pair of

extensions

15 and 17 at both ends of the vibration plate 9. The first piezoelectric element 11 has a structure in which a plurality of piezoelectric ceramic layers and electrode layers are alternately laminated so as to have a first electrode (not shown) on the front surface and a second electrode (not shown) on the back surface. It is. In the first piezoelectric element 11, a second electrode (not shown) is joined to the surface 9 a of the diaphragm 9 so that the extension surfaces 15 a and 17 a are left on the surfaces of the

extensions

15 and 17 of the diaphragm 9. Then, it is joined to the surface 9 a of the diaphragm 9. Similarly to the first piezoelectric element 11, the second piezoelectric element 13 has a first electrode (not shown) on the front surface and a plurality of piezoelectric ceramic layers and electrode layers alternately so as to have a second electrode (not shown) on the back surface. It is a multilayer piezoelectric element having a structure laminated on. In the second piezoelectric element 13, a second electrode (not shown) is electrically connected to the back surface 9 b of the diaphragm 9 so that the extension surfaces 15 b and 17 b of the

extension portions

15 and 17 are left at both ends of the back surface 9 b of the diaphragm 9. It joins so that conduction | electrical_connection is possible, and it is joined to the back surface 9b of the diaphragm 9. FIG. In this embodiment, multilayer (laminated) piezoelectric elements are used as the first and second

piezoelectric elements

11 and 13, but single-layer piezoelectric elements can also be used as the piezoelectric elements. The piezoelectric vibrating body 3 is supported by the support body 7 so as to be vibrated by supporting the

extension parts

15 and 17 of the vibration plate 9 by a pair of support parts described later of the support body 7. A weight member 5 is attached to the central portion of the piezoelectric vibrating body 3 in the longitudinal direction.

The weight member 5 is composed of a pair of

weight pieces

19 and 21 made of a resin or the like in which brass, tungsten, or metal powder is mixed to increase the specific gravity, and the side surfaces of the pair of

weight pieces

19 and 21 at the center portion in the longitudinal direction thereof. And a connecting portion 22 to be connected. The weight member 5 is attached to the piezoelectric vibrating body 3 so as to sandwich the piezoelectric vibrating body 3 from both sides in the thickness direction by a sandwiching portion 23 composed of the central portion of the pair of

weight pieces

19 and 21 and the connecting portion 22. . In the present embodiment, the weight piece 19 and the weight piece 21 are arranged so that the weight piece 19 faces the first piezoelectric element 11 and the weight piece 21 faces the second piezoelectric element 13. Yes. Therefore, the weight piece 19 and the weight piece 21 are located on both sides in the thickness direction of the piezoelectric vibrating body 3. Each of the pair of

weight pieces

19 and 21 has a shape as viewed from the thickness direction of the piezoelectric vibrating body 3, the width dimension is substantially the same as the width dimension of the piezoelectric element, and the length dimension in the longitudinal direction is the length of the piezoelectric element. It is formed to have a rectangular shape shorter than the length in the direction. In addition, the surfaces of the

weight pieces

19 and 21 that face the first piezoelectric element 11 and the second piezoelectric element 13 are

contact surfaces

19a and 21a that constitute a part of the sandwiching portion 23 at the center in the longitudinal direction, respectively. It is composed of a pair of

inclined surfaces

19b and 21b that are located on both sides of the contact surfaces 19a and 21a and are inclined so that the distance from the first piezoelectric element 11 increases toward the

extended portions

15 and 17. The pair of

weight pieces

19 and 21 may fix the contact surfaces 19a and 21a to the first piezoelectric element 11 and the second piezoelectric element 13 with an adhesive or a double-sided tape. When the weight member 5 has such a structure, the weight member 5 does not hinder the expansion and contraction of the piezoelectric vibrating body 3. In the present embodiment, the pair of

weight pieces

19 and 21 and the connecting portion 22 are integrally formed.

The support body 7 has a main body portion 25 extending in the longitudinal direction with a predetermined interval between the support body 7, a rising portion 26 rising from both longitudinal ends of the main body portion 25, and a leading end portion of the rising portion 26. The first and

second support portions

27 and 29 are provided. The main body 25 has a rectangular plate shape extending in the longitudinal direction. The first and

second support portions

27 and 29 support the

extensions

15 and 17 of the diaphragm 9, respectively. In the present embodiment, the main body portion 25, the rising portion 26, the first support portion 27, and the second support portion 29 are integrally formed by bending a single metal plate such as a stainless steel plate. Yes. The main body 25 is fixed to the housing of the mobile phone.

The first support portion 27 includes a pair of

contact pieces

31 and 33 that contact the extension surface 15 a on the front surface side and the extension surface 15 b on the back surface side of the extension portion 15, and a pair of connections that connect the pair of

contact pieces

31 and 33. The

pieces

34a and 34b are integrally provided. The pair of

contact pieces

31 and 33 integrally have flat plate-

like portions

31a and 33a and

contact portions

31b and 33b formed at the central portions of the flat plate-

like portions

31a and 33a. The

contact portions

31b and 33b are provided with

curved surfaces

31c and 33c that are convex in the direction toward the extended surface 15a and the extended surface 15b of the extended portion 15, respectively. In the present embodiment, the

contact portions

31b and 33b have a substantially semi-cylindrical shape. These

curved surfaces

31c and 33c constitute contact surfaces that come into contact with the extension surfaces 15a and 15b of the extension portion 15.

The second support portion 29 includes a pair of

contact pieces

35 and 37 that contact the extension surface 17 a on the front surface side and the extension surface 17 b on the back surface side of the extension portion 17, and a pair of connections that connect the pair of

contact pieces

35 and 37. The

pieces

41a and 41b are integrally provided. The pair of

contact pieces

35 and 37 integrally have

flat plate portions

35a and 37a and

contact portions

35b and 37b formed at the center of the

flat plate portions

35a and 37a. The

contact portions

35b and 37b include curved surfaces 35c and 37c that are convex in the direction toward the extended surface 17a and the extended surface 17b of the extended portion 17, respectively. In the present embodiment, the

contact portions

35b and 37b have a substantially semi-cylindrical shape. These curved surfaces 35c and 37c constitute contact surfaces that contact the extension surface 17a and the extension surface 17b of the extension portion 17.

In the present embodiment, since the pair of

contact pieces

31 and 33 have a shape that is symmetric with respect to the extension portion 15, the pair of contact pieces 31 and 33 (

contact portions

31b and 33b) face each other. . In addition, since the pair of

contact pieces

35 and 37 also have a symmetrical shape with respect to the extension portion 17, the pair of contact pieces 35 and 37 (

contact portions

35b and 37b) face each other. In the present embodiment, the first and second

piezoelectric elements

11 and 13 expand and contract by supporting the pair of

extension portions

15 and 17 of the diaphragm 9 by the pair of

support portions

27 and 29 having such a structure. The

extension portions

15 and 17 swing around the

contact portions

31d and 33d and 35d and 37d with the pair of

contact pieces

31 and 33 and 35 and 37. As shown in an enlarged scale in FIG. 4, two

contact portions

31 d and 33 d of the extension surfaces 15 a and 15 b of the extension portion 15 and the

curved surfaces

31 c and 33 c of the

contact pieces

31 and 33 are respectively connected to the extension portion 15. This is the center of oscillation of the extended surface (front surface) 15a and the extended surface (back surface) 15b. In FIG. 4, the extended portion 15 after swinging is indicated by a broken line. Similarly, the two

contact points

35d and 37d of the extension surfaces 17a and 17b of the extension portion 17 and the curved surfaces 35c and 37c of the

contact pieces

35 and 37 are the extension surface (surface) 17a and the extension surface of the extension portion 17, respectively. (Back side) The center of oscillation of 17b.

In the above embodiment, when the first piezoelectric element 11 and the second piezoelectric element 13 are expanding and contracting, the extension portion 15 is centered on the contact portion with the

contact pieces

31 and 33 of the first support portion 27. Can swing. Further, the extension portion 17 can swing around the contact portion with the contact pieces 37c and 39c of the second support portion 29. Therefore, the movement of the diaphragm when the first piezoelectric element 11 and the second piezoelectric element 13 expand and contract is hardly restricted. In addition, since the contact piece on the front wall portion and the contact piece on the back wall portion face each other, it is possible to ensure the maximum swing range of the extension portion.

FIG. 5 is a view showing a modified example of the support portion. In FIG. 5, the same number as that of the embodiment shown in FIGS. 1 to 4 is added to the number of the reference numerals attached to the embodiment shown in FIGS. The reference numerals are attached and the description is omitted. The support portion 127 has two contact pieces 131 and a 133 connecting piece 134 connected to one end side in the longitudinal direction of the diaphragm 115.

FIG. 6 is a rear view of a piezoelectric vibration element according to another embodiment of the present invention. In FIG. 6, the same number as that of the embodiment shown in FIGS. 1 to 4 is added to the number of reference numerals attached to the embodiment shown in FIGS. 1 to 4 to the number of 200. The reference numerals are attached and the description is omitted. In the piezoelectric vibration element shown in FIG. 6, the weight member 205 includes one weight piece 221 positioned on the surface side not facing the main body 207 a of the support body 207 of the piezoelectric vibration body 203, and the support body of the piezoelectric vibration body 203. A holding piece 219 that contacts a central portion of the surface facing 207 is connected by a connecting portion 222 to have an integrated structure. Accordingly, the weight member 205 in FIG. 6 is configured such that the piezoelectric vibrating body 203 is sandwiched from the thickness direction by the clamping portion 223 including the contact surface 221a of the central portion of the weight piece 221, the clamping piece 219, and the connecting portion 222. 203 is attached.

In the above embodiment, the bimorph type piezoelectric vibration element has been described, but the present invention can be applied to a unimorph type piezoelectric vibration element.

DESCRIPTION OF SYMBOLS 1 Piezoelectric vibration element 3 Piezoelectric vibration body 5 Weight member 7 Support body 9 Diaphragm 11 1st piezoelectric element 13 2nd piezoelectric element 15 Extension part 17 Extension part 19 Weight piece 21 Weight piece 22 Connection part 23 Holding part 25 Main body part 26 Standing part 27 First support part 29 Second support part 31 Contact piece 31a Flat plate part 31b Contact part 31c Curved surface 33 Contact piece

34a Connection piece

34b Connection piece 35 Contact piece 37 Contact piece 41a Connection piece 41b Connecting piece

Claims

A piezoelectric vibrating body in which one or more piezoelectric elements are bonded to at least one of the front and back surfaces of the elongated diaphragm;
A piezoelectric vibration element comprising a support for supporting the piezoelectric vibration body so as to vibrate;
The diaphragm includes a pair of extension portions to which the piezoelectric element is not bonded at both ends in the longitudinal direction,
The support includes a pair of support portions that support the pair of extensions of the diaphragm,
The support portion has a pair of contact pieces that come into contact with the front surface and the back surface of the extension portion, and the extension portion is centered on a contact portion with the pair of contact pieces when the piezoelectric element is expanding and contracting. And has a structure that supports the extension so as to allow swinging,
The piezoelectric elements are respectively provided on the front surface and the back surface of the diaphragm,
The pair of contact pieces are configured by curved surfaces in which a contact surface that comes into contact with the front surface or the back surface of the extension portion is convex toward the extension portion,
The pair of contact pieces face each other via the extension part,
The support body includes a main body portion extending in the longitudinal direction at a predetermined interval from the piezoelectric vibrator, a rising portion rising from both ends in the longitudinal direction of the main body portion, and a distal end portion of the rising portion. Provided with the support part provided,
The support is integrally formed by bending a single metal plate,
A weight member is attached to the center of the piezoelectric vibrator in the longitudinal direction so as not to inhibit expansion and contraction of the piezoelectric vibrator,
The weight member is attached to the piezoelectric vibrator by a sandwiching portion that sandwiches the piezoelectric vibrator in the thickness direction,
The weight member has a pair of weight pieces that are located on both sides of the piezoelectric vibrating body in the thickness direction and have a shape in which a distance between the weight and the piezoelectric vibrating body is increased toward the pair of extension parts. A piezoelectric vibration element characterized by having an integrated structure.
A piezoelectric vibrating body in which one or more piezoelectric elements are bonded to at least one of the front and back surfaces of the elongated diaphragm;
A piezoelectric vibration element comprising a support for supporting the piezoelectric vibration body so as to vibrate;
The diaphragm includes a pair of extension portions to which the piezoelectric element is not bonded at both ends in the longitudinal direction,
The support includes a pair of support portions that support the pair of extensions of the diaphragm,
The support portion has a pair of contact pieces that come into contact with the front surface and the back surface of the extension portion, and the extension portion is centered on a contact portion with the pair of contact pieces when the piezoelectric element is expanding and contracting. A piezoelectric vibration element characterized by having a structure that supports the extension portion so as to allow it to swing.
3. The piezoelectric vibration element according to claim 2, wherein the piezoelectric element is provided on each of the front surface and the back surface of the vibration plate.
3. The piezoelectric vibrating element according to claim 2, wherein the pair of contact pieces are configured by curved surfaces in which a contact surface that contacts the front surface or the back surface of the extension portion is convex toward the extension portion.
4. The piezoelectric vibrating element according to claim 3, wherein the pair of contact pieces are configured by curved surfaces in which a contact surface that contacts the front surface or the back surface of the extension portion is convex toward the extension portion.
The piezoelectric vibration element according to claim 4 or 5, wherein the pair of contact pieces are directly opposed via the extension.
The support body includes a main body portion extending in the longitudinal direction with a predetermined interval between the support body, a rising portion rising from both ends in the longitudinal direction of the main body portion, and a distal end portion of the rising portion. The piezoelectric vibration element according to claim 2, further comprising the provided support portion.
The piezoelectric vibration element according to claim 7, wherein the support is integrally formed by bending a single metal plate.
The piezoelectric vibration element according to claim 2, wherein a weight member is attached to a central portion of the piezoelectric vibration body in a longitudinal direction so as not to inhibit expansion and contraction of the piezoelectric vibration body.
10. The piezoelectric vibration element according to claim 9, wherein the weight member is attached to the piezoelectric vibration member by a sandwiching portion that sandwiches the piezoelectric vibration member in a thickness direction.
The weight member is connected to a pair of weight pieces that are located on both sides in the thickness direction of the piezoelectric vibrating body and have a shape in which a gap between the piezoelectric vibrating body is widened toward the pair of extension portions. The piezoelectric vibration element according to claim 10, having an integrated structure.
The weight member is located on one side in the thickness direction of the piezoelectric vibrating body, and a weight piece having a shape in which a distance between the piezoelectric vibrating body is widened toward the pair of extension portions, and the piezoelectric vibrating body 11. The piezoelectric vibration element according to claim 10, wherein the piezoelectric vibrating element has a structure in which a holding piece that contacts a central portion of a surface of the support body facing the main body portion is connected by a connecting portion and integrated.