Piezoelectric sound generating components

Abstract

The piezoelectric sound-generating component (1) of the present invention comprises: a piezoelectric vibration plate (2); a housing (6) having a housing body (3) and a cover (4), and accommodating the piezoelectric vibration plate (2) in an internal space (30) formed by the housing body (3) and the cover (4); and a pin terminal (5) arranged on the cover (4) in a manner abutting against the piezoelectric vibration plate (2), the housing body (3) having a first top wall portion (31) and a first peripheral wall portion (32), and the cover (4) having a There is a second top wall portion (41), a second peripheral wall portion (42) and a protrusion portion (44) in contact with the first peripheral wall portion (32) of the shell body (3), and the protrusion portion (44) has: a first surface (441) capable of abutting against the surface of the first peripheral wall portion (32) facing the first top wall portion (31), that is, the contact surface (341); and a second surface (442) connecting the first surface (441) and the second peripheral wall portion (42) and separating it from the first peripheral wall portion (32).

Description

Technical Field

[0001] The invention relates to a piezoelectric sound generating component. Background Art

[0002] Piezoelectric sound generating components are used as electroacoustic transducers for generating alarm sounds or operating sounds in, for example, household appliances, fire alarm equipment and other civil and commercial electronic devices, or automobiles, etc. Piezoelectric sound generating components include those having a pin-shaped mounting terminal called a lead type.

[0003] For example, Patent Document 1 discloses a piezoelectric buzzer including: a piezoelectric vibration plate; a cover; and a housing body that is fitted to the outside of the cover and houses the piezoelectric vibration plate together with the cover. In such a piezoelectric buzzer, the piezoelectric vibration plate is sandwiched between the cover and the housing body, thereby being held in an internal space formed between the top wall of the cover and the top wall of the housing.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2000-333296

[0005] However, the piezoelectric sound generating component such as the piezoelectric buzzer disclosed in Patent Document 1 does not take into account the problem of reduced stability of mounting the cover to the housing body due to the shape of the tip portion of the protrusion of the cover for contacting the housing body, thereby affecting the vibration characteristics of the piezoelectric vibration plate. Summary of the invention

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a piezoelectric sound-generating component capable of obtaining good reliability.

[0007] The piezoelectric sound-generating component involved in one aspect of the present invention comprises: a piezoelectric vibration plate; a shell, comprising a shell body with an opening and a cover that closes the opening of the shell body, and the piezoelectric vibration plate is accommodated in an internal space formed by the shell body and the cover; and a pin terminal is arranged on the cover in a manner of abutting against the piezoelectric vibration plate, the shell body comprising a first top wall portion opposite to a main surface of one side of the piezoelectric vibration plate, and a first peripheral wall portion arranged at an end of the first top wall portion, the cover comprising: a second top wall portion opposite to a main surface of the other side of the piezoelectric vibration plate; a second peripheral wall portion arranged at an end of the second top wall portion and having a holding surface for holding the piezoelectric vibration plate; and a protrusion portion contacting the first peripheral wall portion of the shell body, the protrusion portion comprising: a first surface capable of abutting against a surface of the first peripheral wall portion facing the first top wall portion; and a second surface connecting the first surface to the second peripheral wall portion and separating from the first peripheral wall portion.

[0008] According to the present invention, a piezoelectric sound-generating component capable of obtaining good reliability can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is an exploded perspective view showing the structure of the piezoelectric sound generating component according to the first embodiment.

[0010] Figure 2 It is a cross-sectional view showing the structure of the piezoelectric sound generating component according to the first embodiment.

[0011] Figure 3 It is a diagram showing the structure of the case body and the piezoelectric vibration plate before the cover according to the first embodiment is attached to the case body.

[0012] Figure 4 It is a diagram showing a part of the structure of the cover before being attached to the case body according to the first embodiment.

[0013] Figure 5 It is an enlarged cross-sectional view showing the attached state of the cover and the case body according to the first embodiment.

[0014] Figure 6 yes Figure 5 Stress distribution diagram.

[0015] Figure 7 It is an enlarged cross-sectional view showing a mounted state of the cover and the case body according to the second embodiment.

[0016] Figure 8 yes Figure 7 Stress distribution diagram.

[0017] Fig. 9 It is an enlarged cross-sectional view showing a mounted state of the cover and the case body according to the third embodiment.

[0018] Fig.10 yes Fig. 9 Stress distribution diagram.

[0019] Fig.11 It is an enlarged cross-sectional view showing a mounted state of a cover and a case body according to a comparative example.

[0020] Fig.12 yes Fig.11 Stress distribution diagram. DETAILED DESCRIPTION

[0021] The following is an explanation of the embodiments of the present invention. In the following description of the drawings, the same or similar components are represented by the same or similar reference numerals. The drawings are examples, and the sizes and shapes of the various parts are schematic, and should not be understood as limiting the technical scope of the invention of this application to the embodiments.

[0022] [First embodiment]

[0023] <Piezoelectric sound generating component 1>

[0024] First, refer to Figure 1 and Figure 2 The outline of the piezoelectric sound-generating component 1 according to the first embodiment will be described. Figure 1 This is an exploded perspective view for explaining the structure of the piezoelectric sound-generating component 1 according to the first embodiment. Figure 2 It is a cross-sectional view for explaining the structure of the piezoelectric sound-generating component 1 according to the first embodiment.

[0025] The piezoelectric sound-generating component 1 is an example of a pin-type sound-generating component. Figure 1 and Figure 2 As shown, the piezoelectric sound-generating component 1 includes a piezoelectric diaphragm 2 , a case 6 that accommodates the piezoelectric diaphragm 2 , and two lead terminals 5 that come into contact with the piezoelectric diaphragm 2 to apply a voltage to the piezoelectric diaphragm 2 .

[0026] The housing 6 includes a housing body 3 and a cover 4. The housing body 3 has an opening. The cover 4 is attached to the housing body 3, thereby being able to close the opening of the housing body 3. In other words, the internal space 30 of the housing 6 is constituted by the housing body 3 and the cover 4 attached to the housing body 3. The piezoelectric vibration plate 2 is accommodated in the internal space 30 in a state of being sandwiched by the housing body 3 and the cover 4.

[0027] The two pin terminals 5 are provided on the cover 4. When the piezoelectric vibration plate 2 is accommodated in the internal space 30, the two pin terminals 5 are in contact with the piezoelectric vibration plate 2. Thus, the piezoelectric vibration plate 2 reciprocates in the internal space 30 by the AC voltage applied from the two pin terminals 5, and generates sound (rings).

[0028] Hereinafter, the state in which the piezoelectric sound-generating component 1 is configured by assembling the piezoelectric diaphragm 2 , the case body 3 , the cover 4 , and the two lead terminals 5 may be referred to as an “assembled state”.

[0029] <Details of the piezoelectric sound generating component 1>

[0030] Next, refer to Figures 1 to 4 The details of each structure of the piezoelectric sound generating component 1 will be described. Figure 3 It is a diagram showing the structure of the case body 3 and the piezoelectric diaphragm 2 before the cover 4 according to the first embodiment is attached to the case body 3 . Figure 4 This is a diagram showing a partial structure of the cover 4 before being attached to the case body 3 according to the first embodiment.

[0031] (Piezoelectric vibration plate 2)

[0032] like Figure 1 and Figure 2As shown, the piezoelectric vibration plate 2 includes a substrate 10 and a vibration element 20. The substrate 10 and the vibration element 20 are both disc-shaped members. The diameter of the substrate 10 is larger than the diameter of the vibration element 20. In addition, the vibration element 20 is attached to the central portion of the main surface (the first substrate main surface 11 described later) of one side of the substrate 10 by an adhesive.

[0033] The substrate 10 is made of a material having good electrical conductivity and spring elasticity, such as a metal having an elastic modulus of 1 GPa or more. Specifically, the substrate 10 is preferably made of 42 alloy, SUS (stainless steel), brass, phosphor bronze, etc. In addition, the material of the substrate 10 can be a material other than metal, such as a resin material such as a glass epoxy substrate having an elastic modulus of 1 GPa or more, or a multilayer structure in which a plurality of materials are stacked.

[0034] In addition, the substrate 10 has a first substrate main surface 11 and a second substrate main surface 12 located on both sides in the thickness direction. In the assembled state, the first substrate main surface 11 faces the first direction, and the second substrate main surface 12 faces the second direction. In addition, the first substrate main surface 11 abuts against one of the two pin terminals 5 (the second pin terminal 52 described later).

[0035] The vibration element 20 includes a piezoelectric plate 23 and a pair of electrodes 24 provided on both main surfaces of the piezoelectric plate 23 so as to sandwich the piezoelectric plate 23. The piezoelectric plate 23 is a disk-shaped member and is made of piezoelectric ceramics such as PZT.

[0036] The pair of electrodes 24 is a circular thin film for vibrating the piezoelectric vibration plate 2 by applying a voltage to the piezoelectric plate 23. In addition, the pair of electrodes 24 is made of Ag (sintered silver), or a metal such as Cu, or an alloy of Cu and Ni. In the assembled state, the electrode 24 located in the first direction side is in contact with the other of the two pin terminals 5 (the first pin terminal 51 described later). The electrode 24 located in the second direction is attached to the first substrate main surface 11 of the substrate 10 by a conductive adhesive.

[0037] (Shell body 3)

[0038] The housing body 3 is made of insulating materials such as ceramics and resin. In addition, the housing body 3 is formed in a box shape. Figure 1 and Figure 2 As shown, the housing body 3 has a first top wall portion 31 and a first peripheral wall portion 32 provided at an end of the first top wall portion 31 .

[0039] The first top wall portion 31 is formed in a disk shape. Figure 2As shown, the first top wall portion 31 has top wall main surfaces 311 and 312 located on both sides in the thickness direction. In the assembled state, the top wall main surface 311 faces the first direction and is opposite to the second substrate main surface 12 of the piezoelectric vibration plate 2. The top wall main surface 312 faces the second direction.

[0040] A sound emission hole 313 is provided at the center of the first top wall portion 31. The sound emission hole 313 penetrates the first top wall portion 31 in the thickness direction, and connects the inside and the outside of the housing body 3. Thus, in the assembled state, the sound emission hole 313 releases the sound generated when the piezoelectric vibration plate 2 vibrates to the outside of the housing 6.

[0041] The first peripheral wall portion 32 is formed in a cylindrical shape. Figure 2 As shown, the first peripheral wall portion 32 has an inner peripheral surface 35 , an outer peripheral surface 36 , and an opening portion 33 provided at a distal end side away from the first top wall portion 31 .

[0042] The inner peripheral surface 35 includes a first inner peripheral surface 351 located on the side of the opening 33, a second inner peripheral surface 352 connected to the first top wall 31, and a connecting surface 353 connecting the first inner peripheral surface 351 and the second inner peripheral surface 352. In the assembled state, the second inner peripheral surface 352, the top wall main surface 311, and the piezoelectric vibration plate 2 together constitute the acoustic space 302 located on the second direction side of the internal space 30.

[0043] The connecting surface 353 is a stepped surface between the second inner peripheral surface 352 and the first inner peripheral surface 351, and is provided parallel to the first top wall portion 31. In the assembled state, the connecting surface 353 abuts against the second substrate principal surface 12 of the substrate 10 of the piezoelectric vibration plate 2. In this way, the connecting surface 353 can hold the piezoelectric vibration plate 2 in a manner of clamping from both sides in the thickness direction of the piezoelectric vibration plate 2 together with the holding surface 423 of the cover 4 described later.

[0044] like Figure 3 As shown, the first inner peripheral surface 351 has a claw portion 34 provided on the opening portion 33 side, and a groove portion 354 and an inclined surface 355 provided on the second inner peripheral surface 352 side relative to the claw portion 34. The claw portion 34 is provided over the entire circumference of the opening portion 33 side of the first inner peripheral surface 351. In addition, the claw portion 34 has a contact surface 341 that contacts the cover 4 in the assembled state.

[0045] The contact surface 341 is the surface of the first peripheral wall portion 32 facing the first top wall portion 31. Figure 2 As shown, in the assembled state, the contact surface 341 is arranged to be inclined relative to the first top wall portion 31 and the piezoelectric vibration plate 2 .

[0046] The groove 354 and the slope 355 function as an escape portion. The groove 354 and the slope 355 allow the portion of the cover 4 other than the portion in contact with the contact surface 341 to be separated from the first peripheral wall portion 32 of the case body 3 in the assembled state.

[0047] (Cover 4)

[0048] The cover 4 is made of, for example, the same material as the housing body 3, that is, an insulating material such as ceramic or resin. In addition, the cover 4 is formed in a box shape. Figure 2 and Figure 4 As shown, the cover 4 includes a second top wall portion 41 , a second peripheral wall portion 42 provided at an end of the second top wall portion 41 , and a protrusion 44 that contacts the first peripheral wall portion 32 of the case body 3 .

[0049] The second top wall portion 41 is formed in a disk shape. Figure 2 As shown, the second top wall portion 41 has a bottom wall main surface 411 and a bottom wall main surface 412 located on both sides in the thickness direction. In the assembled state, the bottom wall main surface 412 faces the second direction and is opposite to the first substrate main surface 11 of the piezoelectric vibration plate 2. The bottom wall main surface 411 faces the first direction. In addition, two through holes (not shown) for fixing the two pin terminals 5 are provided in the second top wall portion 41. These through holes penetrate the second top wall portion 41 in the thickness direction.

[0050] The second peripheral wall portion 42 is formed in a cylindrical shape. Figure 4 As shown, the second peripheral wall portion 42 has an inner peripheral surface 45, an outer peripheral surface 46, and an opening portion 43 provided at the end side away from the second top wall portion 41. In addition, the second peripheral wall portion 42 has a holding surface 423 provided at the end side of the second peripheral wall portion 42.

[0051] The inner peripheral surface 45, together with the bottom wall main surface 412 and the piezoelectric vibration plate 2, constitutes the acoustic space 301 located on the first direction side of the internal space 30 in the assembled state. In addition, the escape portion 451 and the escape portion 461 are provided at the end sides of each of the inner peripheral surface 45 and the outer peripheral surface 46. The escape portion 451 and the escape portion 461 can avoid interference between the two pin terminals 5 and the cover 4, and interference between the cover 4 and the first peripheral wall portion 32 of the housing body 3 in the assembled state.

[0052] The holding surface 423 is formed in a flat shape. In addition, the holding surface 423 is set parallel to the bottom wall main surface 412. In the assembled state, the holding surface 423 abuts against the first substrate main surface 11 of the substrate 10 of the piezoelectric vibration plate 2. In this way, the holding surface 423 can hold the piezoelectric vibration plate 2 in a manner of clamping from both sides of the piezoelectric vibration plate 2 in the thickness direction together with the connecting surface 353 of the housing body 3.

[0053] like Figure 1As shown, the protrusion 44 is provided on the outer peripheral side of the second top wall 41 and the second peripheral wall 42 in the main surface direction of the second top wall 41. In the assembled state, the protrusion 44 is the part in contact with the contact surface 341 of the housing body 3. Figure 4 As shown, the protrusion 44 has a first surface 441 , a second surface 442 and a third surface 443 .

[0054] The first surface 441 is a terminal surface located at the outermost peripheral side of the protrusion 44. In addition, the first surface 441 is formed into a curved surface. In addition, the first surface 441 can also be formed into a flat surface. In the assembled state, the first surface 441 abuts against the contact surface 341 of the claw portion 34 provided on the first peripheral wall portion 32 of the housing body 3.

[0055] The second surface 442 is a connecting surface that connects the first surface 441 and the second peripheral wall portion 42. In addition, the second surface 442 is inclined toward the holding surface 423 of the second peripheral wall portion 42. In the assembled state, the second surface 442 is separated from the first peripheral wall portion 32 of the housing body 3. In this way, the second surface 442 is not pressed by the first peripheral wall portion 32 of the housing body 3.

[0056] The third surface 443 is a connecting surface that connects the first surface 441 and the second top wall portion 41. In addition, the third surface 443 is parallel to the holding surface 423 of the second peripheral wall portion 42. In the assembled state, the third surface 443 is separated from the first peripheral wall portion 32 of the housing body 3. In this way, the third surface 443 is not pressed by the first peripheral wall portion 32 of the housing body 3.

[0057] (Pin terminal 5)

[0058] The two pin terminals 5 include a first pin terminal 51 and a second pin terminal 52. The first pin terminal 51 and the second pin terminal 52 are each formed by bending a wire having a substantially circular cross-sectional shape. By using such a bent shape, the first pin terminal 51 and the second pin terminal 52 can obtain elasticity. In addition, the wire is, for example, composed of a phosphor bronze wire material with Sn plating applied on the surface.

[0059] The first pin terminal 51 and the second pin terminal 52 are fixed to the cover 4 via two through holes provided in the second top wall portion 41 of the cover 4. In the assembled state, the first pin terminal 51 and the second pin terminal 52 are in contact with the piezoelectric vibration plate 2 and are electrically connected thereto.

[0060] Specifically, if Figure 2As shown, the first pin terminal 51 is electrically connected to the electrode 24 located on the first direction side of the piezoelectric vibration plate 2. The second pin terminal 52 is electrically connected to the electrode 24 located on the second direction side of the piezoelectric vibration plate 2 by being connected to the substrate 10 of the piezoelectric vibration plate 2. In this way, the first pin terminal 51 and the second pin terminal 52 can apply an AC voltage to the pair of electrodes 24 of the piezoelectric vibration plate 2.

[0061] <Attachment of Cover 4 and Case Body 3>

[0062] Next, refer to Figures 3 to 5 The attachment of the cover 4 to the case body 3 will be described. Figure 5 It is an enlarged cross-sectional view showing a mounted state of the cover 4 and the case body 3 according to the first embodiment.

[0063] like Figure 5 As shown, in the assembled state, the cover 4 is mounted and fixed to the case body 3. In addition, in this case, the case body 3 and the cover 4 hold the piezoelectric vibration plate 2 in the internal space 30 by sandwiching the piezoelectric vibration plate 2. Therefore, the mounting of the cover 4 and the case body 3 includes the fixing of the cover 4 and the case body 3, and the holding of the piezoelectric vibration plate 2 by the fixed cover 4 and the case body 3.

[0064] In the process of attaching the cover 4 to the case body 3, first, the piezoelectric vibration plate 2 is placed on the connecting surface 353 of the case body 3 so that the second substrate principal surface 12 of the substrate 10 of the piezoelectric vibration plate 2 is in contact with the connecting surface 353 of the case body 3. Next, the cover 4 is inserted toward the inside of the case body 3 through the opening 33 of the case body 3 so that the holding surface 423 of the second peripheral wall portion 42 of the cover 4 is in contact with the first substrate principal surface 11 of the substrate 10 of the piezoelectric vibration plate 2 placed on the connecting surface 353.

[0065] Here, if Figure 3 As shown in FIG. 1 , before the cover 4 is inserted into the housing body 3, when the piezoelectric diaphragm 2 is placed on the connection surface 353 of the housing body 3, the straight line distance from the first substrate main surface 11 of the piezoelectric diaphragm 2 to the contact surface 341 of the housing body 3 is L1. Figure 4 As shown, in the cover 4 before being inserted into the housing body 3, the straight line distance from the holding surface 423 of the cover 4 to the first surface 441 of the protrusion 44 is L2. Here, the distance L2 is greater than the distance L1. Therefore, as Figure 5 As shown, when the cover 4 is inserted into the interior of the shell body 3 and abuts against the piezoelectric vibration plate 2, the second peripheral wall portion 42 and the protrusion 44 of the cover 4 are embedded between the first substrate main surface 11 of the piezoelectric vibration plate 2 placed on the connecting surface 353 and the contact surface 341 of the shell body 3.

[0066] In such an embedded state, the first surface 441 of the protrusion 44 of the cover 4 receives pressure in the direction having the second direction component from the contact surface 341 of the claw 34 abutting against the first surface 441. The holding surface 423 of the second peripheral wall portion 42 of the cover 4 receives pressure in the first direction from the piezoelectric vibration plate 2 placed on the connection surface 353 abutting against the holding surface 423. In other words, the cover 4 is pressed against the piezoelectric vibration plate 2 placed on the connection surface 353 by the pressure from the contact surface 341 of the claw 34. At the same time, the cover 4 is pressed against the contact surface 341 of the claw 34 by the reaction force of the pressure from the contact surface 341 of the piezoelectric vibration plate 2 placed on the connection surface 353.

[0067] In this way, the second peripheral wall portion 42 and the protrusion 44 of the cover 4 are restricted by the connecting surface 353 and the contact surface 341 of the housing body 3. As a result, the cover 4 is mounted and fixed relative to the housing body 3. At the same time, the piezoelectric vibration plate 2 is clamped and held by the cover 4 and the housing body 3. In addition, in the embedded state, the first surface 441 of the protrusion 44 of the cover 4 is partially deformed from a curved surface to a flat surface due to the pressure applied.

[0068] <Effects of using cover 4>

[0069] Next, refer to Figure 5 , Figure 6 , Fig.11 as well as Fig.12 , the stress distribution when the cover 50 involved in the comparative example is installed on the shell body 3 is compared, and the stress distribution when the cover 4 involved in the first embodiment is installed on the shell body 3 is explained, and the effect of using the cover 4 involved in the first embodiment is explained. Figure 6 yes Figure 5 Stress distribution diagram. Fig.11 It is an enlarged cross-sectional view showing a mounted state of the cover 50 and the case body 3 according to the comparative example. Fig.12 yes Fig.11 Stress distribution diagram.

[0070] (Comparative Example)

[0071] The piezoelectric sound-generating component according to the comparative example is different from the piezoelectric sound-generating component 1 according to the first embodiment in that the protrusion 54 of the cover 50 of the piezoelectric sound-generating component according to the comparative example. Fig.11As shown in FIG. 1 , the protrusion 54 according to the comparative example includes a terminal end 541, a second surface 542, and a third surface 543. The terminal end 541 of the protrusion 54 is a portion that contacts the housing body 3 in the assembled state. On the other hand, unlike the first surface 441 of the protrusion 44 according to the first embodiment, the terminal end 541 according to the comparative example is an intersection line of the second surface 542 and the third surface 543. That is, the terminal end 541 according to the comparative example is not formed in a planar shape but in a linear shape.

[0072] Thus, in the assembled state, the contact between the terminal end 541 of the comparative example and the contact surface 341 of the shell body 3 is a line contact. In addition, when there is a deviation in the shape of the contact surface 341 of the claw portion 34 of the shell body 3, there is a case where a part of the terminal end 541 cannot contact the contact surface 341 of the shell body 3. In such a case, the contact between the terminal end 541 of the comparative example and the contact surface 341 of the shell body 3 sometimes becomes a point contact. Therefore, in the assembled state, the contact area between the terminal end 541 of the comparative example and the contact surface 341 of the shell body 3 is small. In addition, according to the shape of the terminal end 541, the size of the terminal portion of the terminal side of the protrusion 54 of the comparative example that contacts the contact surface 341, that is, the terminal portion clamped by the intersecting second surface 542 and third surface 543 is also small.

[0073] In this way, Fig.12 As shown in FIG. 1 , in the assembled state, due to the pressure from the contact surface 341 of the housing body 3, a large stress is generated at the end 541 involved in the comparative example. In addition, since the size of the end portion of the end 541 is small, the pressure on the end 541 cannot be fully diffused inside the end portion of the protrusion 54. Therefore, as shown in FIG. Fig.12 As shown, stress concentration occurs at the end portion of the protrusion 54 involved in the comparative example. As a result, the protrusion 54 of the cover 50 involved in the comparative example becomes structurally unstable due to the large internal stress, and there is a possibility of structural damage. If such damage to the protrusion 54 occurs, the protrusion 54 cannot reliably contact the contact surface 341 of the shell body 3. Therefore, the cover 50 cannot reliably press the piezoelectric vibration plate 2. As a result, the fixed state of the piezoelectric vibration plate 2 is unstable, so the deviation of the vibration characteristics of the piezoelectric vibration plate 2 becomes larger, and the reliability of the piezoelectric sound-generating component is reduced.

[0074] (First Embodiment)

[0075] In contrast, the cover 4 of the first embodiment solves the problem of the comparative example by using a protrusion 44 having a first surface 441. The first surface 441 of the first embodiment is formed into a curved surface. Therefore, even if there is a deviation in the shape of the contact surface 341 of the claw 34 of the shell body 3, the protrusion 44 of the cover 4 can use the curved surface shape of the first surface 441 to adjust the contact position between the first surface 441 and the contact surface 341. In this way, the first surface 441 and the contact surface 341 can be reliably contacted, and point contact between the two can be prevented. In addition, in the assembled state, the first surface 441 of the protrusion 44 is partially deformed into a plane due to the pressure from the contact surface 341 of the shell body 3. Therefore, in the assembled state, at least a part of the contact between the first surface 441 of the protrusion 44 of the cover 4 and the contact surface 341 of the shell body 3 becomes a surface contact. Thus, the contact area between the first surface 441 of the cover 4 and the contact surface 341 of the housing body 3 is larger than the line contact or point contact between the end 541 of the cover 50 and the contact surface 341 of the housing body 3 in the comparative example. Figure 6 As shown, when the cover 4 according to the first embodiment is used, the stress generated on the first surface 441 of the protrusion 44 of the cover 4 is smaller than when the cover 50 according to the comparative example is used.

[0076] In addition, if Figure 5 As shown, unlike the end 541 involved in the comparative example, the first surface 441 has a certain area. Therefore, the size of the end portion of the protrusion 44 sandwiched by the second surface 442 and the third surface 443 provided on both sides of the first surface 441 is larger than the size of the end portion of the protrusion 54 sandwiched by the second surface 542 and the third surface 543 involved in the comparative example. Therefore, compared with the comparative example, the pressure applied to the first surface 441 can be fully diffused inside the end portion of the protrusion 44. In this case, as Figure 6 As shown, stress concentration does not occur at the tip portion of the protrusion 44 involved in the first embodiment. In this way, the protrusion 44 of the cover 4 involved in the first embodiment will not be broken due to excessive internal stress. Therefore, the protrusion 44 of the cover 4 involved in the first embodiment can maintain the stability of contact with the contact surface 341 of the housing body 3. Therefore, the cover 4 can reliably press the piezoelectric vibration plate 2. As a result, the fixed state of the piezoelectric vibration plate 2 is stable, so the deviation of the vibration characteristics of the piezoelectric vibration plate 2 can be reduced, thereby improving the reliability of the piezoelectric sound-generating component.

[0077] In addition, a part of the pressure from the contact surface 341 of the housing body 3 can be transmitted toward the holding surface 423 of the second peripheral wall portion 42 of the cover 4 by the guidance of the second surface 442 of the protrusion 44. As a result, the force acting on the piezoelectric vibration plate 2 by the holding surface 423 of the second peripheral wall portion 42 of the cover 4 becomes larger than that of the comparative example. Therefore, the cover 4 can hold the piezoelectric vibration plate 2 more stably and reliably. As a result, the deviation of the vibration characteristics of the piezoelectric vibration plate 2 can be further reduced, and the reliability of the piezoelectric sound generating component can be improved.

[0078] As described above, in the first embodiment, by using the protrusion 44 having the above-mentioned characteristics, it is possible to provide a piezoelectric sound-generating component that can obtain good reliability.

[0079] [Second embodiment]

[0080] Next, refer to Figure 7 and Figure 8 The attachment of the cover 7 and the case body 3 according to the second embodiment will be described. Figure 7 It is an enlarged cross-sectional view showing a mounted state of the cover 7 and the case body 3 according to the second embodiment. Figure 8 yes Figure 7 Stress distribution diagram.

[0081] In the following description, the description of the matters common to the first embodiment in the second embodiment is omitted, and the description is focused on the different point, that is, the structure of the protrusion 74 of the cover 7. In particular, the same functions and effects brought about by the same structure are not mentioned.

[0082] like Figure 7 As shown, unlike the structure of the second surface 442 of the protrusion 44 of the cover 4 involved in the first embodiment, the second surface 742 of the protrusion 74 of the cover 7 involved in the second embodiment is provided to connect the first surface 741 of the protrusion 74 and the holding surface 723 of the second peripheral wall portion 72. In this way, the protrusion 74 involved in the second embodiment is larger than the protrusion 44 involved in the first embodiment. The second surface 742 constitutes the outer peripheral surface of the second peripheral wall portion 72. In addition, the angle between the second surface 742 and the holding surface 723 is an obtuse angle.

[0083] In this way, Figure 8As shown, in the second embodiment, by adopting the cover 7 having the above-mentioned protrusion 74, the pressure from the contact surface 341 of the housing body 3 to the first surface 741 of the protrusion 74 can be guided and directly transmitted to the holding surface 723. Therefore, the holding force applied by the holding surface 723 of the cover 7 to the piezoelectric vibration plate 2 becomes larger, and the cover 7 can reliably hold the piezoelectric vibration plate 2. In addition, the second surface 742 of the protrusion 74 constitutes the outer peripheral surface of the second peripheral wall portion 72, so the size of the protrusion 74 and the end portion of the protrusion 74 involved in the second embodiment is larger than that of the protrusion 44 and the end portion of the protrusion 44 involved in the first embodiment. Therefore, the strength of the protrusion 74 involved in the second embodiment can be improved. At the same time, the pressure received by the first surface 741 of the protrusion 74 can be fully diffused inside the end portion of the protrusion 74. As a result, the stress concentration occurring at the end portion of the protrusion 74 involved in the second embodiment can be more reliably reduced.

[0084] [Third Embodiment]

[0085] Next, refer to Fig. 9 and Fig.10 The attachment of the cover 8 and the case body 3 according to the third embodiment will be described. Fig. 9 It is an enlarged cross-sectional view showing a mounted state of the cover 8 and the case body 3 according to the third embodiment. Fig.10 yes Fig. 9 Stress distribution diagram.

[0086] In the following description, the description of matters common to the first embodiment of the third embodiment is omitted, and the description is focused on the different point, that is, the structure of the protrusion 84 of the cover 8. In particular, the same functions and effects brought about by the same structure are not mentioned.

[0087] like Fig. 9 As shown, unlike the structure of the second surface 442 of the protrusion 44 of the cover 4 involved in the first embodiment, the second surface 842 of the protrusion 84 of the cover 8 involved in the third embodiment is set to be parallel to the holding surface 823 of the second peripheral wall portion 82 of the cover 8. In this way, the protrusion 84 involved in the third embodiment is smaller than the protrusion 44 involved in the first embodiment. On the other hand, the first surface 841 of the protrusion 84 involved in the third embodiment is larger than the first surface 441 of the protrusion 44 involved in the first embodiment.

[0088] In this way, Fig.10As shown, in the third embodiment, by adopting the cover 8 having the above-mentioned protrusion 84, the range in which the first surface 841 of the protrusion 84 can contact the contact surface 341 of the shell body 3 becomes larger. Therefore, the range in which the cover 8 can adjust the deviation of the contact surface 341 of the shell body 3 becomes larger. In addition, compared with the protrusion 44 involved in the first embodiment, the protrusion 84 involved in the third embodiment is smaller. Therefore, in the assembled state, in order to avoid interference between the shell body 3 and the protrusion 84 of the cover 8, the avoidance space that needs to be provided in the shell body 3 becomes less. As a result, the strength of the shell body 3 can be strengthened, and the design freedom of the shell body 3 can be improved.

[0089] In the above, exemplary embodiments of the present invention have been described.

[0090] In a piezoelectric sound-generating component 1 according to an embodiment of the present invention, there is provided: a piezoelectric vibration plate 2; a housing 6 having a housing body 3 with an opening and a cover 4 closing the opening of the housing body 3, wherein the piezoelectric vibration plate 2 is accommodated in an internal space 30 formed by the housing body 3 and the cover 4; and a pin terminal 5 provided on the cover 4 in a manner abutting against the piezoelectric vibration plate 2, the housing body 3 having a first top wall portion 31 facing a main surface of the piezoelectric vibration plate 2, and a first peripheral wall portion 32 provided at an end of the first top wall portion 31, and the cover 4 It has: a second top wall portion 41, which is opposite to the other main surface of the piezoelectric vibration plate 2; a second peripheral wall portion 42, which is arranged at the end of the second top wall portion 41 and has a holding surface 423 for holding the piezoelectric vibration plate 2; and a protrusion 44, which is in contact with the first peripheral wall portion 32 of the shell body 3, and the protrusion 44 has: a first surface 441, which can abut against the surface of the first peripheral wall portion 32 facing the first top wall portion 31, that is, the contact surface 341; and a second surface 442, which connects the first surface 441 to the second peripheral wall portion 42 and separates it from the first peripheral wall portion 32.

[0091] According to the above configuration, by improving the stability of attachment of the cover to the case body, it is possible to reduce variations in vibration characteristics of the piezoelectric diaphragm, and to obtain a piezoelectric sound-generating component with excellent reliability.

[0092] In addition, the first surface 441 of the protrusion 44 may be formed in a curved shape or a flat shape.

[0093] According to the above configuration, by increasing the area of ​​the contact surface of the protrusion, the stability of mounting can be improved.

[0094] In the above configuration, the second surface 442 of the protrusion 44 may be parallel to the holding surface 423 .

[0095] According to the above configuration, by making the shape of the protrusion smaller, the degree of freedom in designing the entire piezoelectric sound-generating component can be increased.

[0096] In the above configuration, the second surface 442 of the protrusion 44 may be inclined toward the holding surface 423 .

[0097] According to the above configuration, the force generated inside the protrusion can be transmitted to the holding surface, and the stability of the mounting can be improved.

[0098] In the above configuration, the second surface 442 of the protrusion 44 may connect the first surface 441 of the protrusion 44 and the holding surface 423 of the second peripheral wall 42 , and the angle between the second surface 442 and the holding surface 423 may be an obtuse angle.

[0099] According to the above configuration, by directly transmitting the force generated inside the protrusion to the holding surface, the stability of the mounting can be improved, and the strength of the protrusion can be enhanced.

[0100] In the above structure, the contact surface 341 of the first peripheral wall portion 32 facing the first top wall portion 31 may be inclined relative to the main surface of the piezoelectric vibration plate 2 , and the first surface 441 of the protrusion 44 may be a terminal surface located on the terminal side of the protrusion 44 .

[0101] According to the above configuration, by stabilizing the fixed state of the piezoelectric diaphragm, it is possible to reduce variations in the vibration characteristics of the piezoelectric diaphragm, and to improve the reliability of the piezoelectric sound generating component.

[0102] In addition, each embodiment described above is for easy understanding of the present invention, and is not for limiting the interpretation of the present invention. The present invention can be changed / improved without departing from its main purpose, and the present invention also includes its equivalent. That is, those skilled in the art make appropriate design changes to each embodiment, as long as they have the features of the present invention, they are included in the scope of the present invention. For example, each element and its configuration, material, condition, shape, size, etc. possessed by each embodiment are not limited to examples and can be appropriately changed. In addition, each embodiment is an example, and of course, local replacement or combination of the structures shown in different embodiments can be performed, and these are also included in the scope of the present invention as long as they include the features of the present invention.

[0103] Description of Reference Numerals

[0104] 1…piezoelectric sound-generating component; 2…piezoelectric vibration plate; 3…housing body; 4…cover; 5…pin terminal; 6…housing; 10…substrate; 20…vibration element; 23…piezoelectric plate; 24…electrode; 30…inner space; 31…first top wall; 32…first peripheral wall; 34…claw; 41…second top wall; 42…second peripheral wall; 44…protrusion; 341…contact surface; 441…first surface; 442…second surface.

Claims

1. A piezoelectric sound-generating component, wherein: have: Piezoelectric vibration plate; A housing having a housing body with an opening and a cover for closing the opening of the housing body, wherein the piezoelectric vibration plate is accommodated in an internal space formed by the housing body and the cover; as well as A pin terminal is provided on the cover so as to abut against the piezoelectric vibration plate. The housing body includes a first top wall portion facing one main surface of the piezoelectric vibration plate, and a first peripheral wall portion provided at an end of the first top wall portion. The cover comprises: a second top wall portion facing the main surface of the other side of the piezoelectric vibration plate; a second peripheral wall portion provided at an end of the second top wall portion and having a holding surface for holding the piezoelectric vibration plate; and a protrusion portion contacting the first peripheral wall portion of the housing body. The protrusion has a first surface capable of contacting a surface of the first peripheral wall portion facing the first top wall portion, and a second surface connecting the first surface to the second peripheral wall portion and separating the first surface from the first peripheral wall portion.

2. The piezoelectric sound generating component according to claim 1, wherein: The first surface of the protrusion is formed in a curved shape or a flat shape.

3. The piezoelectric sound generating component according to claim 1 or 2, wherein: The second surface of the protrusion is parallel to the holding surface.

4. The piezoelectric sound generating component according to claim 1 or 2, wherein: The second surface of the protrusion is inclined toward the holding surface.

5. The piezoelectric sound generating component according to claim 4, wherein: The second surface of the protrusion connects the first surface of the protrusion and the holding surface of the second peripheral wall. An angle between the second surface and the retaining surface is an obtuse angle.

6. The piezoelectric sound-generating component according to any one of claims 1 to 5, wherein: The surface of the first peripheral wall portion facing the first top wall portion is inclined relative to the two main surfaces of the piezoelectric vibration plate. The first surface of the protrusion is a distal end surface located on a distal end side of the protrusion.

Images