JP6658699B2 - Piezoelectric sounding body - Google Patents

Description

  The present invention relates to a piezoelectric sounding body, and more particularly, to a piezoelectric sounding body having high connection reliability between a conductive terminal and a piezoelectric diaphragm.

  The piezoelectric sounding body mainly includes a piezoelectric diaphragm, a case for holding the piezoelectric diaphragm inside, and a pair of conductive terminals fixed to the case and electrically connected to the piezoelectric diaphragm. Such a piezoelectric sounding body is generally mounted on household electric appliances (refrigerator, washing machine, remote control for air conditioner, etc.), a sounding unit of a fire alarm, and the like.

  In the piezoelectric sounding body disclosed in Patent Literature 1, each conductive terminal is fixed to the inner surface of the case by a fixing portion such as thermal caulking. The external connection portion of the conductive terminal protruding from the case is connected to a circuit board or the like by means such as solder reflow.

  However, in the conventional piezoelectric sounding body, heat at the time of solder reflow is transmitted to the conductive terminal, and the heat is transmitted to the fixing portion made of resin, so that the fixing between the fixing portion and the conductive terminal may be loosened. In particular, the conductive terminal is connected to the piezoelectric vibrating plate by a spring force, and the spring force may act as a reaction on the fixed portion, and when heat is transmitted to the fixed portion, the fixed portion and the conductive terminal may be fixed. There was a risk of loosening.

  When the connection between the conductive terminal and the fixing portion is loosened, the spring force of the conductive terminal on the piezoelectric vibration plate is weakened, and in extreme cases, there is a problem that poor connection between the conductive terminal and the piezoelectric vibration plate is likely to occur.

JP 07-114383 A

  The present invention has been made in view of such circumstances, and an object thereof is to provide a piezoelectric sounding body having high connection reliability between a conductive terminal and a piezoelectric diaphragm.

In order to achieve the above object, the piezoelectric sounding body according to the present invention is:
A piezoelectric diaphragm,
A case for holding the piezoelectric diaphragm inside,
A conductive terminal electrically connected to the piezoelectric diaphragm, and a piezoelectric sounding body,
The inner surface of the case has an upper surface and a middle surface lower in the height direction than the upper surface,
The conductive terminal,
An external connection portion extending from the case to the outside,
A horizontal portion formed continuously with the external connection portion and extending along the middle step surface;
A rising portion that is formed continuously to the horizontal portion and is raised toward the piezoelectric vibration plate,
A contact portion formed on the tip side of the rising portion and electrically connected to the piezoelectric vibration plate,
The horizontal portion near the external connection portion is embedded in a fixing portion formed on the inner surface of the case,
The horizontal portion near the rising portion is exposed on the inner surface of the case along a step wall between the upper step surface and the middle step surface.

  In the piezoelectric sounding body of the present invention, the contact portion of the conductive terminal is satisfactorily connected to the piezoelectric vibrating plate by the spring force generated by the bending deformation of the rising portion. Moreover, the horizontal portion continuing to the rising portion is arranged along a step wall formed along the boundary between the middle and upper steps of the inner surface of the case. For this reason, the spring force acting on the conductive terminal acts so as to press the horizontal portion exposed on the inner surface of the case against the stepped wall surface. Therefore, it is possible to suppress the spring force acting on the conductive terminal from directly acting on the fixing portion.

  Therefore, in the piezoelectric sounding body according to the present invention, even when the heat at the time of solder reflow is transmitted to the conductive terminal and the heat is transmitted to the fixing portion made of resin, the direction in which the fixing between the fixing portion and the conductive terminal is loosened. Can be suppressed from acting on the spring force. Therefore, it is possible to prevent the spring force of the conductive terminal against the piezoelectric vibration plate from weakening, and to improve the connection reliability between the conductive terminal and the piezoelectric vibration plate.

  Preferably, the inner surface of the case further has a lower surface lower in the height direction than the middle surface, and the rising portion near the contact portion is located on the lower surface. With this configuration, it is possible to increase the distance between the rising portion near the contact portion and the lower step surface, and it is possible to set the bending deformation of the rising portion large. As a result, the connection reliability between the conductive terminal and the piezoelectric diaphragm can be further improved. Alternatively, the size of the piezoelectric sounding body in the height direction can be reduced.

  The fixing portion may be formed by heat-sealing a fixing projection formed on the upper step surface. For example, by applying a heating iron to the fixing protrusion, the fixing protrusion may be thermally deformed, and a part of the horizontal portion closer to the external connection portion may be integrated with the case by a thermal caulking method.

  Further, a detent portion may be formed at a part of the conductive terminal which is located near a boundary between the external connection portion and the horizontal portion and is embedded inside the fixing portion. With such a configuration, the positioning of the horizontal portion located inside the case and the positioning of the rising portion are performed, thereby facilitating assembly.

  The detent portion may have a flat cross-sectional shape or a curved shape. For example, a flat cross section can be easily formed by pressing a part of a conductive terminal having a circular cross section from both sides. Further, for example, the curved shape can be easily formed by bending a part of the conductive terminal. Note that the detent portion may be formed in a part of the horizontal portion exposed inside the case.

FIG. 1A is a longitudinal sectional view of a piezoelectric sounding body according to one embodiment of the present invention. FIG. 1B is an exploded perspective view of the piezoelectric sounding body shown in FIG. 1A. FIG. 2 is a plan view of the lower part of the case to which the conductive terminals shown in FIG. 1B are attached. FIG. 3 is a perspective view of a lower portion of the case to which the conductive terminal shown in FIG. 1B is attached, and shows a state before a fixing portion is formed by heat fusion. FIG. 4A is a perspective view of one conductive terminal shown in FIG. FIG. 4B is a perspective view of the other conductive terminal shown in FIG. FIG. 4C is a perspective view according to a modification of the one conductive terminal shown in FIG. 3. FIG. 5 is a perspective view of the piezoelectric sounding body shown in FIG. 1A as viewed from an outer surface of a lower portion of the case.

  Hereinafter, the present invention will be described based on embodiments shown in the drawings.

(Overall configuration of piezoelectric sounding body 2)
As shown in FIGS. 1A and 1B, the piezoelectric sounding body 2 according to the first embodiment of the present invention includes a case 10, a piezoelectric vibrating plate 4, and a pair of conductive terminals (a first conductive terminal 50 and a second conductive terminal). 60). The case 10 includes a case upper part 10a and a case lower part 10b. The piezoelectric vibration plate 4 is held inside the case 10.

  The first conductive terminal 50 and the second conductive terminal 60 are connected to the piezoelectric vibration plate 4 respectively. By applying an AC voltage between the first conductive terminal 50 and the second conductive terminal 60, the piezoelectric vibrator 4a undergoes stretching vibration. With the expansion and contraction vibration of the piezoelectric vibrator 4a, the metal plate 4b (entire piezoelectric vibration plate 4) vibrates in the Z-axis direction and emits sound. In the drawings, the X axis, the Y axis, and the Z axis are substantially perpendicular to each other, and in the present embodiment, the X axis is arranged such that the external connection portions 52 and 62 of the conductive terminals 50 and 60 are separated from each other. The Z axis is the height direction of the piezoelectric sounding body 2. An XY plane (a plane including the X axis and the Y axis) is parallel to the plane of the piezoelectric vibration plate 4.

(Case upper part 10a)
The case upper part 10a has a circular structure in the XY plane direction perpendicular to the Z-axis direction. The outer diameter of the case upper part 10a in the XY direction is not particularly limited, but is usually about 5 to 30 mm. The height (height in the Z-axis direction) of the case upper part 10a is not particularly limited, but is usually about 3 to 15 mm.

  At approximately the center of the case upper part 10a in the XY plane direction, a sound emission hole 14 is formed. The diameter of the sound emission hole 14 in the XY plane direction is not particularly limited, but is usually about 2 to 10 mm.

  An engagement recess 12 is formed inside the lower end of the case upper part 10a in the Z-axis direction. The engaging concave portion 12 is fitted with an engaging convex portion 11 formed intermittently along an outer periphery of an inner surface (upper surface in the Z-axis direction) 20 of a case lower portion 10b described later. The material of the case upper part 10a is not particularly limited, but usually, a synthetic resin or the like is used.

(Case lower part 10b)
The case lower part 10b has a circular disk structure in the XY plane direction. The outer diameter of the case lower part 10b on the XY plane is substantially equal to that of the case upper part 10a. As shown in FIGS. 2 and 3, an inner surface 20 of the case lower part 10 b (an inner surface of the case 10) includes an upper surface 21, a middle surface 22 which is one step lower than the upper surface 21 in the Z-axis direction, and a middle surface. A lower step surface 23 which is one step lower in the Z-axis direction than the surface 22 is formed.

  These step surfaces 21, 22, 23 are planes substantially parallel to the XY plane, and have different heights in the Z-axis direction. These step surfaces 21, 22, 23 are preferably planes substantially parallel to the XY plane, but may be curved. The step surfaces 21, 22, and 23 are preferably substantially parallel to the piezoelectric vibrating plate 4, that is, a plane substantially parallel to the XY plane, but may be slightly inclined. The arrangement pattern of these step surfaces 21, 22, 23 is determined according to the shape of the conductive terminals 50 and 60 described later.

A step wall surface 212 is formed at the boundary between the upper step surface 21 and the middle step surface 22, and a step wall surface 223 is formed at the boundary between the middle step surface 22 and the lower step surface 23. A step wall 213 is formed at the boundary with 23. The height of each of the step wall surface 212 and the step wall surface 223 in the Z-axis direction is preferably 0.5 to 1.5 times the wire diameter of the terminal pins constituting the conductive terminals 50 and 60, and more preferably 0.5 to 1.5 times. 8 times to 1.2 times, which are preferably equal, but may be different. The height of the step surface 213 is determined by the step surface 212 and the step surface 22.
Equivalent to the sum of three heights. In the present embodiment, the step surfaces 212, 223, and 213 are parallel to the YZ plane (a plane including the Y axis and the Z axis) or the XZ plane (a plane including the X axis and the Z axis). It may be inclined with respect to the plane or the XZ plane.

  As shown in FIGS. 1A and 2, terminal through holes 15 and 16 penetrating from the upper surface 20 toward the outer surface 30 are formed in the lower case portion 10b before heat caulking (thermal fusion) described later. It is. In the terminal through holes 15 and 16, through portions 54 and 64 of the conductive terminals 50 and 60, each of which is constituted by a metal pin or the like, respectively penetrate. The upper portions of the terminal through holes 15 and 16 are closed after thermal caulking, with the through portions 54 and 64 of the conductive terminals 50 and 60 penetrating therethrough.

  In the present embodiment, the terminal through holes 15 and 16 are formed at a predetermined pitch in the X-axis direction in the disc-shaped case lower portion 10b. The predetermined pitch is determined in relation to the outer diameter of the disc-shaped case lower part 10b, preferably in the range of 1/4 to 3/4 of the outer diameter, and more preferably 3/8 of the outer diameter. ５5/8.

  As shown in FIGS. 2 and 3, fixing projections 24, 24 protruding in the Z-axis direction are formed on the upper surface 21 so as to surround the terminal through holes 15, 16 from three directions, respectively. The fixing projections 24, 24 are U-shaped projections as viewed from the Z-axis direction, and have guide grooves 25, 25 formed therein, each opening on the opposite side in the Y-axis direction.

  The bottoms of the guide grooves 25, 25 are formed by middle surfaces 22, 22, respectively, and guide the horizontal portions 56, 66 of the conductive terminals 50, 60 described later from the guide grooves 25, 25 to the internally exposed middle step surfaces 22, 22, respectively. It is supposed to. The inner exposed middle steps 22, 22 are middle steps 22, 22 not surrounded by the fixing projections 24, 24. The fixing protrusions 24, 24 are portions that will be fixed by applying a heating iron and heat-sealed (heat caulked) in a later process to form the fixing portions 24a, 24a shown in FIG. 1B. Therefore, it can be said that the inner exposed middle step surfaces 22 are the middle step surfaces 22 exposed from the fixing portions 24a.

  As shown in FIG. 5, bosses 32, 32 protruding in the Z-axis direction are formed around the terminal through holes 15, 16 on the outer surface 30 of the disc-shaped case lower part 10 b, respectively. The boss portions 32, 32 are formed with thicker portions 34, 34 each having a semilunar shape when viewed from the X-axis direction, outside the X-axis direction. By providing the thick portions 34, 34, buckling of the external connection portions 52, 62 of the conductive terminals 50, 60 near the through holes 15, 16 can be effectively prevented. The material of the case lower part 10b is not particularly limited, but usually the same synthetic resin as that of the case upper part 10a is used.

(Piezoelectric diaphragm 4)
As shown in FIG. 1B, the piezoelectric vibration plate 4 includes a metal plate 4b as a substrate and a piezoelectric vibrator 4a having electrodes formed on both surfaces. The piezoelectric vibrator 4a is joined to the metal plate 4b via an electrode. The metal plate 4b, the electrode, and the piezoelectric vibrator 4a are bonded to each other by, for example, a conductive adhesive. In the present embodiment, the electrodes are regarded as a part of the piezoelectric vibrator 4a.

  The material of the metal plate 4b is not particularly limited, but usually, brass or a Ni alloy is used. The material of the electrode is not particularly limited, but usually Ag or the like is used. The material of the piezoelectric vibrator 4a is not particularly limited as long as it has a piezoelectric vibration property. Usually, a ferroelectric ceramic such as PZT (lead zirconate titanate) is used.

  Each shape of the metal plate 4b and the piezoelectric vibrator 4a is not particularly limited, but usually has a concentric structure on the XY plane. In the XY plane, the diameter of the metal plate 4b is larger than the outer diameter of the electrode and the outer diameter of the piezoelectric vibrator 4a, and the outer diameter of the electrode is equal to or less than the outer diameter of the piezoelectric vibrator 4a. That is, in the XY plane direction, the piezoelectric vibrator 4 a is located substantially at the center of the metal plate 4 b (piezoelectric vibrating plate 4), and the outer peripheral portion of the metal plate 4 b is exposed at the outer peripheral portion of the piezoelectric vibrating plate 4. I have.

  The outer diameter of the metal plate 4b is not particularly limited, but is usually about 5 to 30 mm. The thickness (thickness in the Z direction) of the metal plate 4b is not particularly limited, but is usually about 30 to 300 μm.

  The outer diameter of the piezoelectric vibrator 4a is not particularly limited, but is usually about 3 to 28 mm. The thickness (thickness in the Z direction) of the piezoelectric vibrator 4a is not particularly limited, but is usually about 30 to 300 μm. The thickness of the electrode (the thickness in the Z direction) is not particularly limited, but is usually about 5 to 20 μm.

  As shown in FIG. 1A, the outer peripheral portion of the metal plate 4 b is sandwiched between the engaging concave portion 12 of the case upper portion 10 a and the engaging convex portion 11 of the case lower portion 10 b, so that the entire piezoelectric vibration plate 4 It is held and fixed inside. In addition, the outer peripheral convex part 11 is in line contact with the outer peripheral part of the metal plate 4b. As a result, the vibration of the piezoelectric vibrating plate 4 is less likely to be hindered by the contact of the outer peripheral projection 11.

(Conductive terminals 50 and 60)
Each of the conductive terminals 50 and 60 shown in FIGS. 1A to 3 is formed of, for example, a metal pin having a wire diameter of about φ0.2 to φ1.0 mm, and has different shapes from each other. Have in common. The details will be described below.

  As shown in FIG. 4A, one first conductive terminal 50 has an external connection part 52, a penetrating part 54, a horizontal part 56, a rising part 58, and a contact part 59, and these are a single unit. It is obtained by bending a metal rod or plate. The external connection part 52 extends linearly in the Z-axis direction. The penetrating part 54 is integrated with the upper part of the external connection part 52 in the Z-axis direction. The horizontal portion 56 is bent in the Y-axis direction from the upper end of the through portion 54 in the Z-axis direction.

  As shown in FIG. 2, the overall length Y0a of the horizontal portion 56 in the Y-axis direction is formed longer than the length of the guide groove 25 in the Y-axis direction, and the length Y1a exposed on the inner exposed middle step surface 22 is smaller than zero. It is determined to be larger. The exposed length Y1a may be equal to or more than 1/2 of the total length Y0a of the horizontal portion 56, preferably 1/10 to 9/10, and more preferably 1/4 to 3/4.

  By setting the exposed length Y1a to less than の of the total length Y0a of the horizontal portion 56, the length of the horizontal portion 56 that is thermally caulked by the fixing projection 24 increases, and the fixing strength tends to be improved. . In this case, the length of the conductive terminal 50 exposed from the fixing portion 24a shown in FIG. 1B to the inside of the case 10 is reduced, and the spring rigidity of the portion tends to increase.

  On the other hand, when the exposed length Y1a shown in FIG. 2 is set to be equal to or more than の of the total length Y0a of the horizontal portion 56, the conductive terminal exposed from the fixing portion 24a shown in FIG. 50 becomes longer, and the spring stiffness of that portion tends to increase. In addition, the exposed length L1a of the horizontal portion 56 increases, and the portion guided along the step wall 212 also increases. The total length Y0a of the horizontal portion 56 is determined according to the outer diameter of the lower case portion 10b, and is preferably 1/6 or more and less than 1/2, more preferably 1/5 to 1/3 of the outer diameter. is there.

  As shown in FIG. 4A, the rising portion 56 rises from the tip of the horizontal portion 56 in the Y-axis direction at a predetermined angle in the Z-axis direction from the X-axis. The contact portion 59 is provided at the tip of the rising portion 58 and is formed at the highest position in the Z-axis direction. In the present embodiment, the contact portion 59 is formed by bending the tip of the rising portion 58 downward at a predetermined angle in the Z-axis direction.

  As shown in FIG. 1A, near the center of the piezoelectric vibrating plate 4, the contact portion 59 of the conductive terminal 50 is in contact with and electrically connected to the piezoelectric vibrator 4a via an electrode. The rising portion 58 rises at a predetermined angle from the inner surface 20 toward the piezoelectric vibration plate 4 in a space between the inner surface 20 of the case lower portion 10b and the piezoelectric vibration plate 4. The predetermined angle is preferably an angle of 5 ° to 60 ° with respect to the inner surface 20 (XY plane).

  As shown in FIG. 1A, the through portion 54 is a portion that is inserted into the terminal through hole 15. As shown in FIG. 4A, a detent part 54a may be formed in a part of the penetrating part 54. The detent portion 54a may have, for example, a flat cross-sectional shape or a curved shape. For example, a flat cross section can be easily formed by pressing a part of the conductive terminal 50 having a circular cross section from both sides. Further, for example, the curved shape can be easily formed by bending a part of the conductive terminal 50.

  By changing the shape of the stepped surface of the through hole 15 shown in FIG. 1A in accordance with the shape of the rotation preventing portion 54a, the conductive terminal 50 is prevented from rotating with respect to the case lower portion 10b via the penetration portion 54. It is attached. With this configuration, as shown in FIG. 3, the positioning of the horizontal portion 56 located on the inner surface 20 of the case lower portion 10b and the positioning of the rising portion 58 are easily performed, and the assembly is facilitated.

  The material of the conductive terminal 50 is not particularly limited as long as it is a conductive material, but a metal is used in the present embodiment. The conductive terminal 50 can be easily obtained by pressing and bending a cylindrical (round pin) metal pin.

  As shown in FIG. 4B, similarly to the first conductive terminal 50, the other second conductive terminal 60 includes an external connection portion 62, a through portion 64, a horizontal portion 66, a rising portion 68, and a contact portion 69. Which are obtained by bending a single metal bar or plate. The external connection part 62 extends linearly in the Z-axis direction. The penetrating part 64 is integrated with the upper part of the external connection part 62 in the Z-axis direction. The horizontal portion 66 is bent in the Y-axis direction from the upper end of the through portion 64 in the Z-axis direction.

  As shown in FIG. 2, the overall length Y0b of the horizontal portion 66 in the Y-axis direction is formed longer than the length of the guide groove 25 in the Y-axis direction, and the length Y1b exposed on the inner exposed middle step surface 22 is smaller than zero. It is determined to be larger. The exposed length Y1b may be equal to or more than 1/2 of the total length Y0b of the horizontal portion 66, preferably 1/10 to 9/10, and more preferably 1/4 to 3/4. The exposed length Y1b is determined in the same manner as the exposed length Y1a, and may be the same as or different from the exposed length Y1a. The example shown is different. Further, the overall length Y0a of the horizontal portion 66 is determined in the same manner as the length Y0a of the horizontal portion 56, and may be the same or different, and is different in the illustrated example.

  As shown in FIG. 4B, the rising portion 66 rises from the tip of the horizontal portion 66 in the Y-axis direction at a predetermined angle in the Z-axis direction from the X-axis. The contact portion 69 is provided at the tip of the rising portion 68 and is formed at the highest position in the Z-axis direction. In the present embodiment, the contact portion 69 is formed by bending the tip of the rising portion 68 upward at a predetermined angle in the Z-axis direction.

  As shown in FIG. 1A, near the center of the piezoelectric vibrating plate 4, the contact portion 69 of the conductive terminal 60 is in contact with and electrically connected to the piezoelectric vibrator 4a via the metal plate 4b. The rising portion 68 is raised at a predetermined angle from the inner surface 20 toward the piezoelectric diaphragm 4 in a space between the inner surface 20 of the case lower portion 10 b and the piezoelectric diaphragm 4. The predetermined angle of the rising portion 64 is determined within a range of the predetermined angle of the rising portion 58 of the conductive terminal 50, and the angle may be the same or different.

  As shown in FIG. 1A, the through portion 64 is a portion that is inserted into the terminal through hole 16. As shown in FIG. 4B, a rotation preventing portion 64a may be formed in a part of the penetrating portion 64. The detent portion 64a may have, for example, a flat cross-sectional shape or a curved shape. For example, a flat cross section can be easily formed by pressing a part of the conductive terminal 60 having a circular cross section from both sides. Further, for example, a curved shape can be easily formed by bending a part of the conductive terminal 60.

  By changing the shape of the stepped surface of the through hole 16 shown in FIG. 1A in accordance with the shape of the rotation preventing portion 64a, the conductive terminal 60 is prevented from rotating with respect to the case lower portion 10b via the through portion 64. It is attached. With this configuration, as shown in FIG. 3, the positioning of the horizontal portion 66 located on the inner surface 20 of the case lower portion 10b and the positioning of the rising portion 68 are facilitated, and assembly is facilitated.

  The material of the conductive terminal 60 is preferably the same as the material of the conductive terminal 50, but may be different. The method of forming the conductive terminal 60 is the same as that of the conductive terminal 50, but may be different.

  In the piezoelectric sounding body 2 of the present embodiment, as shown in FIG. 1B, the horizontal portions 56 and 66 near the external connection portions 52 and 62 are embedded in the fixing portion 24a, and as shown in FIG. The horizontal portions 56 and 66 near the upper portions 58 and 68 are exposed on the inner surface 20 of the case 10 along a step wall 212 between the upper step surface 21 and the middle step surface 22. The horizontal portions 56 and 66 exposed on the inner surface 20 are preferably in contact with both the step wall surface 212 and the middle step surface 22.

  As shown in FIG. 1A, in the piezoelectric sounding body 2 of the present embodiment, the contact portions 59 and 69 of the conductive terminals 50 and 60 are attached to the piezoelectric vibrating plate 4 by a spring force generated by bending deformation of the rising portions 58 and 68. Connect well. Moreover, as shown in FIG. 3, the horizontal portions 56 and 66 continuous with the rising portions 58 and 66 are formed by stepped wall surfaces formed along a boundary between the middle step surface 22 and the upper step surface 21 of the inner surface 20 of the case lower portion 10b. It is arranged along 212.

  Therefore, the spring force acting on the rising portions 58, 68 of the conductive terminals 50, 60 acts to press the horizontal portions 56, 66 exposed on the inner surface 20 of the case against the step wall 212 and the middle surface 22. I do. Therefore, it is possible to suppress the spring force acting on the conductive terminals 50 and 60 from directly acting on the fixing portion 24a shown in FIG. 1B.

  Therefore, in the piezoelectric sounding body 2 according to the present embodiment, it is assumed that the heat at the time of solder reflow is transmitted from the external connection portions 52 and 62 to the conductive terminals 50 and 60, and the heat is transmitted to the fixing portion 24a made of resin. However, the following situation can be avoided. That is, it is possible to suppress the spring force from acting in a direction in which the fixing portion 24a is fixed to the horizontal portions 56, 66 of the conductive terminals 50, 60 or the fixing portion 24a is not fixed to the through portions 54, 64. . Therefore, it is possible to prevent the spring force from weakening due to the bending deformation of the rising portions 58 and 68 with respect to the piezoelectric vibration plate 4, and it is possible to improve the connection reliability between the contact portions 59 and 69 and the piezoelectric vibration plate 4.

  Further, in the present embodiment, the rising portions 58 and 68 near the contact portions 59 and 69 are located on the upper portion of the lower step surface 23 in the axial direction. With such a configuration, it is possible to increase the distance between the lower portions 23 and the rising portions 58 and 68 near the contact portions 59 and 69, and to set the bending deformation of the rising portions 58 and 68 to be large. Will be possible. As a result, the connection reliability between the contact portions 59 and 69 of the conductive terminal and the piezoelectric vibration plate 4 can be further improved. Alternatively, the size of the piezoelectric sounding body 2 in the Z-axis height direction can be reduced.

  Further, in this embodiment, as shown in FIG. 3, the fixing portions 24a, 24a shown in FIG. 1B are formed by heat-sealing fixing fixing portions 24 formed on the upper step surface 21. For example, by applying a heating iron to the Z-axis upper surface of the fixing protrusion 24, the fixing protrusion 24 can be thermally deformed. That is, the fixing portions 24a, 24a shown in FIG. 1B can be formed by integrating a part of the horizontal portions 56, 56 on the side close to the external connection portions 52, 62 with the case lower portion 10b by the thermal caulking method.

  Note that the present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the present invention.

  For example, as shown in FIG. 4C, the detent portion 56a may be formed in a part of the horizontal portion 56 (or 66). At least a part of the detent part 56a formed on a part of the horizontal part 56 may be embedded in the fixed part 24a shown in FIG. 1B, but may be exposed from the fixed part 24a. In this case, the rotation preventing portion 56a is preferably parallel to the middle surface 22 (XY plane), but is not necessarily required.

  The substrate of the piezoelectric vibrating plate 4 does not necessarily need to be the metal plate 4b. For example, when the electrode covers the entire surface of the substrate 4 facing the piezoelectric vibrator 4a and the other conductive terminal 60 is brought into contact with the substrate-side electrode, the substrate itself may be an insulator. In this case, the same operation and effect as those of the above-described embodiment can be obtained.

2 Piezoelectric sound generator 4 Piezoelectric vibrating plate 4a Piezoelectric vibrator 4b Piezoelectric vibrator 10 Case 10a Case upper part 10b Case lower part 11 Engagement convex part 12 Engagement concave part 14 Sound emitting hole 15, 16 ... Terminal through hole 20 ... Inner surface 21 ... Upper step surface 212,213,223 ... Step wall surface 22 ... Middle step surface 23 ... Lower step surface 24 ... Fixing convex part 24a ... Fixing part 25 ... Guide groove 30 ... Outer surface 32 ... Boss part 34 ... Thick portions 50, 60 Conductive terminals 52, 62 External connection portions 54, 64 Through portions 54a, 64a Detent portions 56, 66 Horizontal portions 56a Detent portions 58, 68 Standup portions 59, 69 Contact

Claims (6)

A piezoelectric diaphragm,
A case for holding the piezoelectric diaphragm inside,
A conductive terminal electrically connected to the piezoelectric diaphragm, and a piezoelectric sounding body,
The inner surface of the case has an upper surface and a middle surface lower in the height direction than the upper surface,
The conductive terminal,
An external connection portion extending from the case to the outside,
A horizontal portion formed continuously with the external connection portion and extending along the middle step surface;
A rising portion that is formed continuously to the horizontal portion, and is raised toward the piezoelectric vibration plate from a tip of the horizontal portion ,
A contact portion formed on the distal end side of the rising portion and electrically connected to the piezoelectric vibration plate,
The horizontal portion near the external connection portion is embedded in a fixing portion formed on the inner surface of the case,
The horizontal portion near the rising portion is exposed on the inner surface of the case, along a step wall between the upper step surface and the middle step surface,
The rising portion is formed by bending the spring portion generated from the bending deformation of the rising portion from the tip of the horizontal portion so that the horizontal portion exposed on the inner surface of the case is pressed against the stepped wall surface. A piezoelectric sounding body characterized in that: A piezoelectric diaphragm,
A case for holding the piezoelectric diaphragm inside,
A conductive terminal electrically connected to the piezoelectric diaphragm, and a piezoelectric sounding body,
The inner surface of the case has an upper surface and a middle surface lower in the height direction than the upper surface,
The conductive terminal,
An external connection portion extending from the case to the outside,
A horizontal portion formed continuously with the external connection portion and extending along the middle step surface;
A rising portion that is formed continuously to the horizontal portion, and is raised toward the piezoelectric vibration plate from a tip of the horizontal portion ,
A contact portion formed on the distal end side of the rising portion and electrically connected to the piezoelectric vibration plate,
The horizontal portion near the external connection portion is embedded in a fixing portion formed on the inner surface of the case,
The horizontal portion near the rising portion is exposed on the inner surface of the case, along a step wall between the upper step surface and the middle step surface,
The piezoelectric sounding body, wherein the rising portion is formed by being bent from a tip of the horizontal portion toward a side facing the step wall surface. The inner surface of the case further has a lower step surface lower in a height direction than the middle step surface,
The piezoelectric sounding body according to claim 1, wherein the rising portion close to the contact portion is located on the lower step surface.   The piezoelectric sounding body according to any one of claims 1 to 3, wherein the fixing portion is formed by heat-bonding a fixing protrusion formed on the upper step surface.   5. A detent part is formed at a part of the conductive terminal which is located near a boundary between the external connection part and the horizontal part and is embedded inside the fixing part. A piezoelectric sounding body as described in Crab.   The piezoelectric sounding body according to claim 5, wherein the detent portion has a flat cross-sectional shape or a curved shape.

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