Patent Publication Number: US-10311853-B2

Title: Piezoelectric sounding body

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to Japanese Application No. 2015-159036, filed Aug. 11, 2015. The disclosure of the priority application is incorporated in its entirety herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a piezoelectric sounding body that generates a certain sound by vibration of a piezoelectric vibrating plate. 
     2. Description of the Related Art 
     For example, in the likes of an automobile or various kinds of household electrical appliances, a piezoelectric sounding body is sometimes adopted as a sounding body that generates a buzzer sound or the like. The piezoelectric sounding body applies a cyclical voltage signal to a piezoelectric vibrating plate, thereby vibrating the piezoelectric vibrating plate and generating a specific sound (for example, a warning sound, and so on) that attracts the attention of a user, or the like. 
     In a conventional a piezoelectric sounding body, a case housing the piezoelectric vibrating plate mainly consists of two members of a case body and a lid member, and the piezoelectric vibrating is sandwiched between the case body and the lid member. As a technique for fixing the case body and the lid member, a technique for engaging the case body and the lid member, a technique for bonding the case body and the lid member, and the like are disclosed (see Patent Documents 1 and 2). 
     Patent Document 1: JP H11-52958 A 
     Patent Document 2: Japanese Patent No. 3861809 
     SUMMARY OF THE INVENTION 
     The conventional techniques for engaging the case body and the lid member to fix them have problems in reliability because an engagement state between the case body and the lid member is subject to be affected by the external environment, and a fixed state of the piezoelectric vibrating plate sandwiched by the case body and the lid member may be affected by vibration and varied. As with the case of engaging the case body and the lid member to fix them, the conventional techniques for bonding the case body and the lid member to fix them have problems because a fixed state between the case body and the lid member may be affected by the external environment and varied as time goes by. 
     The present invention has been made in view of such circumstances, it is an object of the invention to provide a piezoelectric sounding body having a holding state that is hardly varied due to influence of the external environment and a high reliability. 
     In order to achieve the above object, a piezoelectric sounding body according to the present invention comprises: 
     a piezoelectric vibrating plate; 
     a case housing the piezoelectric vibrating plate; 
     a first conductive terminal electrically connected to one electrode in the piezoelectric vibrating plate; and 
     a second conductive terminal electrically connected to the other electrode in the piezoelectric vibrating plate, 
     wherein the case includes: 
     a lower case where the first conductive terminal and the second conductive terminal are fixed; and 
     an upper case configured to be fixed in a caulking manner to the lower case and to sandwich the piezoelectric vibrating plate between the upper case and the lower case, and 
     the upper case includes: 
     a contact projection configured to contact the piezoelectric vibrating plate and to press it toward the lower case; and 
     an upper case lower surface configured to face the piezoelectric vibrating plate or the lower case with respect to a pressing direction where the piezoelectric vibrating plate is pressed toward the lower case and be arranged with space to the piezoelectric vibrating plate or the lower case. 
     In the piezoelectric sounding body configured to fix the upper case and the lower case in a caulking manner, the piezoelectric vibrating plate has a holding state that is hardly varied by influence of the external environment, and the piezoelectric vibrating plate can be securely held by being sandwiched between the upper case and the lower case. Also, the contact projection of the upper case presses the piezoelectric vibrating plate toward the lower case, and the upper case lower surface is positioned with space to the piezoelectric vibrating plate or the lower case, which can prevent space from occurring between the contact projection and the piezoelectric vibrating plate, and improve sealing property of the contact portion between the contact projection and the piezoelectric vibrating plate. 
     For example, a sealing resin may be arranged on a contact portion between the piezoelectric vibrating plate and the contact projection. 
     This sealing resin can prevent space from occurring between the contact projection and the piezoelectric vibrating plate and improve sealing property of the contact portion. 
     For example, a plurality of insertion holes where a caulking projection for fixing the upper case in a caulking manner to the lower case is inserted may be formed in the upper case and have a lower opening positioned on the upper case lower surface. 
     The lower opening of the insertion hole inserted by the caulking projection is formed on the upper case lower surface positioned with space to the lower case, which allows a fixing force of the caulking fixing to preferably act to press the piezoelectric vibrating plate toward the lower case due to the contact projection, and can improve sealing property of the contact portion between the contact projection and the piezoelectric vibrating plate. 
     For example, the contact projection may extend along a circumferential direction of the piezoelectric vibrating plate and the insertion hole may be positioned farther than the contact protrusion with respect to a center of the piezoelectric vibrating plate. 
     The insertion hole inserted by the caulking projection is positioned outside the contact projection extending along the circumferential direction of the piezoelectric vibrating plate. This allows a fixing force of the caulking fixing to preferably act on the contact projection of the upper case in a direction where the piezoelectric vibrating plate is pressed, and improve sealing property of the contact portion between the contact projection and the piezoelectric vibrating plate. 
     For example, the upper case lower surface may include: a first upper case lower surface configured to have part of an opening edge of the lower opening; and a second upper case lower surface configured to have another part of the opening edge, to be positioned farther from the contact projection than the first upper case lower surface, and to have the space being narrower than that of the first upper case lower surface. 
     The first upper case lower surface near the contact projection is configured to have a large space to the piezoelectric vibrating plate or the lower case, and the second upper case lower surface far from the contact projection is configured to have a small space to the lower case etc. This can prevent a three applied to the contact portion from locally being too large while improving sealing property of the contact portion between the contact-point part and the piezoelectric vibrating plate. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view of a piezoelectric sounding body according to an embodiment of the present invention. 
         FIG. 2  is an exploded cross-sectional view of the piezoelectric sounding body shown in  FIG. 1 . 
         FIG. 3  is a schematic plan view showing a state of a lower case and a conductive terminal of the piezoelectric sounding body shown in  FIG. 1  as seen from above. 
         FIG. 4  is a plan view showing the lower case prior to assembly used for the piezoelectric sounding body shown in  FIG. 1 . 
         FIG. 5A  is a plan view showing a first conductive terminal used for the piezoelectric sounding body shown in  FIG. 1 . 
         FIG. 5B  is a plan view showing a second conductive terminal used for the piezoelectric sounding body shown in  FIG. 1 . 
         FIG. 6  is a schematic perspective view of the first conductive terminal shown in  FIG. 5A . 
         FIG. 7  is a cross-sectional view showing an assembled state of an upper case, a piezoelectric vibrating plate, and the lower case. 
         FIG. 8  is a partial enlarged cross-sectional view. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention will be described below based on an embodiment shown in the drawings. 
       FIG. 1  is a schematic perspective view of a piezoelectric sounding body  10  according to an embodiment of the present invention. As shown in  FIG. 1 , the piezoelectric sounding body  10  includes a case  30  configured by an upper case  40  and a lower case  50 . The case  30  houses a piezoelectric vibrating plate  20  shown in  FIG. 2  and a first conductive terminal  60  and a second conductive terminal  70  that are electrically connected to electrodes of the piezoelectric vibrating plate  20 . As shown in  FIG. 1 , other parts of the first conductive terminal  60  and the second conductive terminal  70  are exposed to the outside of the case  30 . 
       FIG. 2  is an exploded cross-sectional view of the piezoelectric sounding body  10  shown in  FIG. 1 . The piezoelectric vibrating plate  20  has an outer shape of circular plate. The piezoelectric vibrating plate  20  has a two-layer structure in which a piezoelectric body  22  and a vibrating plate  24  both having a circular plate shape are concentrically stacked, and the vibrating plate  24  arranged upwardly has a larger diameter than the piezoelectric body  22  arranged downwardly. A vibrating plate outer circumferential portion  24   a  of the vibrating plate  24  is an outside portion of an outer periphery of the piezoelectric body  22  and is placed on a lower case step part  51 . 
     The vibrating plate  24  functions as one electrode of the piezoelectric vibrating plate  20 . The other electrode  22   a  of the piezoelectric vibrating plate  20  is formed on a lower surface of the piezoelectric body  22 . Moreover, the vibrating plate  24  as one electrode and the other electrode  22   a  are insulated, and a voltage is applied to the piezoelectric body  22  via the vibrating plate  24  and the other electrode  22   a . The piezoelectric body  22  is made of any material with an electrode formed on a piezoelectric material, and is configured, for example, by forming the electrode  22   a , such as Ag, on the likes of ferroelectric ceramics, such as PZT (lead zirconate titanate). The vibrating plate  24  is also made of any material, such as metal material of brass, Ni alloy, or the like. Note that the vibrating plate  24  may be joined to the piezoelectric body  22  via a base electrode, such as Ag, formed on the surface of the piezoelectric body  22 . 
     As shown in  FIG. 1  and  FIG. 2 , the upper case  40  has a substantially hollow cylindrical outer shape where a sound emitting hole  42  is formed on its upper center. As shown in  FIG. 2 , an edge part of the sound emitting hole  42  configures a cylindrical part  44  protruding downwardly, and the cylindrical part  44  is arranged inside the upper case  40 . An opening diameter of the sound emitting hole  42  or protrusion length of the cylindrical part  44  is properly adjusted based on the likes of a pitch of sound generated by the piezoelectric sounding body  10 . 
     The upper case  40  has any diameter of its periphery, such as about 10 to 30 mm. Moreover, the upper case  40  has also any height, such as about 3 to 15 mm. 
     As shown in  FIG. 2 , a contact projection  45  (see  FIG. 1 ) is formed in the circumferential direction of the lower end of the upper case  40 . The contact projection  45  extends along the circumferential direction of the piezoelectric vibrating plate  20 , and has a ring shape as seen from below. 
     As shown in  FIG. 7 , which displays an assembled state of the upper case  40 , the lower case  50 , and the piezoelectric vibrating plate  20 , the contact projection  45  of the upper case  40  contacts the vibrating plate outer circumferential portion  24   a  of the piezoelectric vibrating plate  20 . The contact projection  45  presses the vibrating plate outer circumferential portion  24   a  toward the lower case step part  51  formed on the lower case  50  to fix it to the case  30 . That is, the piezoelectric vibrating plate  20  is sandwiched between the contact projection  45  and the lower case step part  51  and held by the upper case  40  and the lower case  50 . Note that  FIG. 7  does not illustrate the first conductive terminal  60  or the second conductive terminal  70  shown in  FIG. 2 . 
     Engaging parts  46   a  and  46   b  projecting toward the outer diameter direction are formed at four places in an outer periphery of the upper case  40  (see  FIG. 1 ). As shown in  FIG. 7 , insertion holes  46   aa  and  46   ba  for inserting case caulking projections  56  provided on the lower case  50  are formed in the respective engaging parts  46   a  and  46   b . The upper case  40  is fixed to the lower case  50  due to caulking by inserting the case caulking projections  56  into the insertion holes  46   aa  and  46   ba  of the engaging parts  46   a  and  46   b . The insertion holes  46   aa  and  46   ba  are positioned farther to a center  20   a  of the piezoelectric vibrating plate  20  than the contact projection  45 . Note that a state where the upper case  40  and the lower case  50  are fixed will be explained in detail below. 
       FIG. 4  is a plan view of the lower case  50 . As shown in  FIG. 4 , the lower case  50  has a substantially rectangular outer shape when viewed from above. The lower case step part  51  where the vibrating plate outer circumferential portion  24   a , which is the outer circumferential portion of the piezoelectric vibrating plate  20 , is arranged is formed on the lower case  50 . The lower case step part  51  is formed along the circumferential direction of the upper case  40 , and has a planer shape corresponding to a shape of the contact projection  45  of the upper case  40 . Note that, as shown in  FIG. 4 , the lower case step part  51  is divided by a notch  59  formed in the lower case  50 , and hence is not continuous in the circumferential direction. The notch  59  is an air hole provided for being able to appropriately generate sound by the piezoelectric sounding body  10 . This air hole has any shape and is positioned anywhere. 
     As shown in  FIG. 4 , the four corners of the lower case  50  are provided with the case caulking projections  56  for fixing the upper case  40  to the lower case  50  in a caulking manner. The case caulking projections  56  project upwardly. As shown in  FIG. 7 , the lower case step part  51  where the piezoelectric vibrating plate  20  is placed is continuous to base portions of the case caulking projections  56 . A projection lower recess  53   c  for preventing warp of the lower case  50  is formed on back side of the case caulking projections  56 . 
     As shown in  FIG. 4 , guide parts  56   a  and  56   b  engaged with the engaging parts  46   a  and  46   b  of the upper case  40  are formed on the periphery of the four case caulking projections  56 . The engaging parts  46   a  and  46   b  of the upper case  40  and the guide parts  56   a  and  56   b  of the lower case  50  have a lateral shape corresponding to each other. The upper case  40  and the lower case  50  are combined in a correct position, so that the engaging parts  46   a  and  46   b  of the upper case  40  are engaged with the guide parts  56   a  and  56   b  of the lower case  50 , and the case caulking projections  56  of the lower case  50  are inserted through the insertion holes  46   aa  and  46   ba  formed in the engaging parts  46   a  and  46   b  of the upper case  40  (see  FIG. 7 ). 
     At least one pair of the guide part  56   b  and the engaging part  46   b  of the corresponding four pairs of the guide parts  56   a  and  56   b  and the engaging parts  46   a  and  46   b  have a different shape from the other guide parts  56   a  and engaging parts  46   a . This prevents the engaging parts  46   a  and  46   b  from engaging with the guide parts  56   a  and  56   b  when attempting to combine the upper case  40  and the lower case  50  in an incorrect position (see  FIG. 4  and  FIG. 7 ). 
       FIG. 8  is an enlarged cross-sectional view where a fixed portion of the upper case  40  and the lower case  50  is enlarged. The upper case  40  has an upper case lower surface  48  positioned with space to the piezoelectric vibrating plate  20  or the lower case  50  with respect to a pressing direction where the piezoelectric vibrating plate  20  is pressed toward the lower case  50 . A lower opening  46   ab  of the insertion hole  46   aa  where the case caulking projection  56  is inserted is arranged on an upper case lower surface  48 . Thus, there is a predetermined space is between the lower case step part  51  where the base of the case caulking projection  56  is connected and the upper case lower surface  48  where the lower opening  46   ab  of the insertion hole  46   aa  is located. 
     As shown in  FIG. 8 , the upper case lower surface  48  has a first upper case lower surface  48   a  and a second upper case lower surface  48   b , both of which respectively have different space to the lower case  50  with respect to the pressing direction. The lower opening  46   ab  of the insertion hole  46   aa  is positioned to cross the first upper case lower surface  48   a  and the second upper case lower surface  48   b . Thus, the first upper case lower surface  48   a  has part of an opening edge of the lower opening  46   ab , and the second upper case lower surface  48   b  has another part of the opening edge of the lower opening  46   ab.    
     The second upper case lower surface  48   b  is positioned farther from the contact projection  45  compared with the first upper case lower surface  48   a . Moreover, the space “b” between the second upper case lower surface  48   b  and the lower case step part  51  is smaller than the space “a” between the first upper case lower surface  48   a  and the piezoelectric vibrating plate  20  (the lower case step part  51  when the piezoelectric vibrating plate  20  does not face the first upper case lower surface  48   a ). 
     As shown in  FIG. 4 , a first terminal insertion hole  54   a  and a second terminal insertion bole  54   b  are formed on the bottom surface of the lower case  50 . The first conductive terminal  60  (see  FIG. 2  and  FIG. 5A ) passes through the first terminal insertion hole  54   a . The second conductive terminal  70  (see  FIG. 2  and  FIG. 5B ) passes through the second terminal insertion hole  54   b . The first terminal insertion hole  54   a  and the second terminal insertion hole  54   b  penetrate the lower case  50  front a lower case inner wall surface  52  to a lower case outer wall surface  53 , which is an outer wan surface of the lower case  50  (see  FIG. 2 ). 
     A plurality (two in the embodiment) of the terminal caulking projections  57   a  for fixing the first conductive terminal  60  to the lower case  50  is formed on the lower case inner wall surface  52 . Moreover, a plurality of (four in the embodiment) auxiliary caulking projections  58   a  is formed on an opening edge of the first terminal insertion hole  54   a . The auxiliary caulking projections  58   a  in conjunction with the terminal caulking projections  57   a  the first conductive terminal  60  to the lower case  50 . 
     A terminal caulking projections  57   b  and an auxiliary caulking projection  58   b , both of which are for fixing the second conductive terminal  70  to the lower case  50 , are formed on the lower case inner wall surface  52 . The auxiliary caulking projection  58   b  is formed along an opening edge of the second terminal insertion hole  54   b . The number of the terminal caulking projections  57   b  and the auxiliary caulking projections  58   b  for fixing the second conductive terminal  70  is the same as the number of the terminal caulking projections  57   a  and the auxiliary caulking projections  58   a  for fixing the first conductive terminal  60 . However, the number of the terminal caulking projections  57   a  and  57   b  and the auxiliary caulking projections  58   a  and  58   b  is not limited to the number shown in the embodiment. 
     The upper case  40  and the lower case  50  can be manufactured by a resin material, such as a liquid crystal polyester resin, a phenol resin, and a polybutylene terephthalate resin. The upper case  40  and the lower case  50  are preferably manufactured by a heat resistant resin so as to be able to endure a thermal load during surface mounting, but are not limited. 
     As shown in  FIG. 2 , the first conductive terminal  60  has a first terminal portion  62 , a second terminal portion  64 , and a third terminal portion  66 . The first terminal portion  62  is arranged inside the case  30  shown in  FIG. 1 . The second terminal portion  64  is arranged outside the case  30 . The third terminal portion  66  is arranged in the first terminal insertion hole  54   a  formed in the lower case  50  of the case  30  to connect the first terminal portion  62  and the second terminal portion  64 . 
     In an assembled state where the piezoelectric vibrating plate  20  is fixed to the lower case step part  51  (see  FIG. 7 ), a terminal edge  62   ca  of the first conductive terminal  60  is electrically connected to the vibrating plate  24 , which is one electrode of the piezoelectric vibrating plate  20 .  FIG. 3  shows a state where the first conductive terminal  60  and the second conductive terminal  70  are fixed to the lower case  50 . The terminal edge  62   ca  of the first conductive terminal  60  is connected to the vibrating plate outer circumferential portion  24   a  of the piezoelectric vibrating plate  20  where the vibrating plate  24  is visible from below. The terminal edge  62   ca  is fixed to the vibrating plate  24  using the likes of a conductive adhesive agent, for example, but the piezoelectric vibrating plate  20  and the first conductive terminal  60  are connected by any method. 
       FIG. 5A  is a plan view of the first conductive terminal  60 . The first terminal portion  62  of the first conductive terminal  60  has a contacting part  62   a , a sandwiching portion  62   b , and a contact-point part  62   c . As shown in  FIG. 2  and  FIG. 6 , the contacting part  62   a  extends in the same plane as the sandwiching portion  62   b . As shown in  FIG. 5A , a plurality (two in the embodiment) of fixing holes  62   aa  for inserting the terminal caulking projections  57   a  of the lower case  50  is formed on the contacting part  62   a . As shown in  FIG. 2  and  FIG. 3 , the contacting part  62   a  is fixed in a caulking manner by the terminal caulking projections  57   a  and the auxiliary caulking projections  58   a  so as to contact the lower case inner wall surface  52 , which is an inner wall surface of the lower case  50 . 
     As shown in  FIG. 3 ,  FIG. 5A , and  FIG. 5B , the sandwiching portion  62   b  of the first terminal portion  62  is connected to one side of the contacting part  62   a , is smaller than the contacting part  62   a , and has a rectangular plate like outer shape. As shown in  FIG. 3 , the auxiliary caulking projections  58   a  may fix the sandwiching portion  62   b  in addition to the contacting part  62   a  of the first terminal portion  62  to the lower case  50  in a caulking manner. 
     As shown in  FIG. 2 , the second terminal portion  64  is arranged on the lower case outer wall surface  53 . At least part of the second terminal portion  64  contacts the lower case outer wall surface  53 , and the sandwiching portion  62   b  contacting the lower case inner wall surface  52  sandwiches part of the lower case  50  between itself and the second terminal portion  64 . 
     As shown in  FIG. 2 , the contact-point part  62   c  extends upwardly with respect to a plane in which the contacting part  62   a  and the sandwiching portion  62   b  are arranged. As shown in  FIG. 5 , a base end of the contact-point part  62   c  is connected to the contacting part  62   a , and the terminal tip  62   ca , which is a tip of the contact-point part  62   c , is fixed to the piezoelectric vibrating plate  20  shown in  FIG. 2 . Thus, the contact point part  62   c  connects the contacting part  62   a  and the piezoelectric vibrating plate  20 . 
     As shown in  FIG. 2  and  FIG. 5 , a bend portion is formed at two places in the contact-point part  62   c . Moreover, as shown in  FIG. 2 , in the fast terminal portion  62 , when an arrangement direction of the sandwiching portion  62   b  and the contacting part  62   a  is assumed to be a first direction and the first terminal portion  62  is viewed in plane from a normal direction to a placement surface of the sandwiching portion  62   b  and the contacting part  62   a , the contact-point part  62   c  extends in a direction intersecting the first direction. Furthermore, the contact-point part  62   c  has a shape that narrows from its base end on a side of the contacting part  62   a  to the terminal tip  62   ca  on a side of the piezoelectric vibrating plate  20 . 
     As shown in  FIG. 6 , the third terminal portion  66  is connected to the contacting part  62   a  of the first terminal portion  62 . The third terminal portion  66  is connected to the same side of the contacting part  62   a  as the side where the sandwiching portion  62   b  is connected to the contacting part  62   a , but the third terminal portion  66  is bent downwardly with respect to the contacting part  62   a , whereas the sandwiching portion  62   b  is arranged in the same plane as the contacting part  62   a.    
     As shown in  FIG. 6 , a through hole  66   a  corresponding to a shape of the sandwiching portion  62   b  is formed on the third terminal portion  66 . Note that an entirety of the through hole  66   a  may be formed in the third terminal portion  66 , and that part of the through hole  66   a  may be continuous to the second terminal portion  64 . The third terminal portion  66  connects the first terminal portion  62  and the second terminal portion  64 . As shown in  FIG. 2 , the third terminal portion  66  is positioned in the first terminal insertion hole  54   a  of the lower case  50 . 
     As shown in  FIG. 2 , a downside part  64   a  of the second terminal portion  64  bent to connect to the third terminal portion  66  is parallel to the sandwiching portion  62   b , and at least part of the downside part  64   a  contacts the lower case outer wall surface  53 . As shown by the dotted lines in  FIG. 4 , a downside recess  53   a  is formed on a surface facing downwardly of the lower case outer wall surface  53 , and the downside part  64   a  of the third terminal portion  66  is arranged in the downside recess  53   a.    
     An end on an opposite side to a side connected to the third terminal portion  66  in the second terminal portion  64  is bent upwardly from the state shown in  FIG. 2  and configures a lateral part  64   b  as shown in  FIG. 1 . As shown in  FIG. 2 , a lateral recess  53   b  is formed on a surface facing laterally of the lower case outer wall surface  53 , and, the lateral part  64   b  of the third terminal portion  66  is arranged on the lateral recess  53   b . The lateral part  64   b  is substantially parallel to the third terminal portion  66  and sandwiches part of the lower case  50  between itself and the third terminal portion  66 . 
     As shown in  FIG. 2 , the second conductive terminal  70 , similarly to the first conductive terminal  60 , also includes: a first terminal portion  72  arranged on the inside of the case  30 ; a second terminal portion  74  arranged on the outside of the case  30 ; and a third terminal portion  76  that connects the first terminal portion  72  and the second terminal portion  74  and is arranged in the second terminal insertion hole  54   b  formed in the lower case  50  of the case  30 . 
       FIG. 5B  is a plan view of the second conductive terminal  70 . As understood from a comparison between  FIG. 5A  and  FIG. 5B , the second conductive terminal  70  has common characteristics with the first conductive terminal  60  in many respects. Thus, the second conductive terminal  70  will be explained mainly in terms of differences from the first conductive terminal  60 , and common points with the conductive terminal  60  will not be explained. 
     In the assembled state where the piezoelectric vibrating plate  20  is fixed to the lower case step part  51  (see  FIG. 7 ), a terminal tip  72   ca  of the second conductive terminal  70  is electrically connected to the other electrode  22   a  of the piezoelectric vibrating plate  20 . As shown in  FIG. 3 , the terminal tip  72   ca  of the second conductive terminal  70  is arranged nearer to the center  50   a  than the terminal tip  62   ca  of the first conductive terminal  60 , and is connected to a portion of the piezoelectric vibrating plate  20  where the vibrating plate  24  is covered from below by the piezoelectric body  22 . The terminal tip  72   ca  of the second conductive terminal  70  is fixed to the other electrode  22   a  using the likes of a conductive adhesive agent. 
     As shown in  FIG. 5B , fixing holes  72   aa , where the terminal caulking projections  57   a  of the lower case  50  are inserted, are also formed on the second conductive terminal  70 , and the second conductive terminal  70  is also fixed in a caulking manner by the terminal caulking projections  57   b  and the auxiliary caulking projections  58   b  (see  FIG. 3 ). 
     The first conductive terminal  60  and the second conductive terminal  70  may be produced using the likes of a good conductor metal, for example, phosphor bronze, but the first conductive terminal  60  and the second conductive terminal  70  are made of any material. Moreover, the first conductive terminal  60  and the second conductive terminal  70  may be applied with the likes of Au plating, Ni plating, or Sn plating. 
     The piezoelectric sounding body  10  shown in  FIG. 1  is manufactured by the following steps, for example. 
     First, in a first step, the lower case  50  shown in  FIG. 4  and the first conductive terminal  60  and second conductive terminal  70  shown in  FIG. 5  are prepared, and the first conductive terminal  60  and the second conductive terminal  70  are attached to the lower case  50 . Note that file upper case  40  and the lower case  50  are manufactured by resin molding such as injection molding, for example, and the first conductive terminal  60  and the second conductive terminal  70  are manufactured by mechanically processing a flat metal plate whose surface has been plated, for example. 
     Next, in a second step, the first conductive terminal  60  and the second conductive terminal  70  are fixed in a caulking manner to the lower case  50 . Specifically, tips of the terminal caulking projections  57   a  and  57   b  of the lower case  50  are heated and thereby deformed so as to be larger than the fixing holes  62   aa  kind  72   aa  of the first conductive terminal  60  and the second conductive terminal  70 . In addition, the auxiliary caulking projections  58   a  and  58   b  are heated and thereby deformed, such that as shown in  FIG. 3 , parts of the auxiliary caulking projections  58   a  and  58   b  contact upper surfaces of the contacting parts  62   a  and  72   a  and the sandwiching portions  62   b  and  72   b . As a result, as shown in  FIG. 4 , an intermediate product in which the first conductive terminal  60  and the second conductive terminal  70  are fixed in a caulking manner to the lower case  50 , is produced. 
     Next, in a third step, the intermediate product produced in the second step, the piezoelectric vibrating plate  20 , and the upper case  40  are prepared, and these three members are assembled as shown in  FIG. 2  and  FIG. 7 . The piezoelectric vibrating plate  20  is, for example, produced by joining the piezoelectric body  22  where the electrode  22   a  is formed to the vibrating plate  24 . The piezoelectric body  22  and the vibrating plate  24  may be joined by adhering the two with the likes of an epoxy adhesive agent, for example, but the piezoelectric body  22  and the vibrating plate  24  are joined by any method. 
     In the third step, first of all, the terminal tips  62   ca  and  72   ca  of the first conductive terminal  60  and the second conductive terminal  70  in the prepared intermediate product are coated with a conductive adhesive agent. Next, the piezoelectric vibrating plate  20  is brought close from above the intermediate product and placed in the lower case step part  51  of the lower case  50 , further, the upper case  40  is brought close to the lower case  50  from above the piezoelectric vibrating plate  20 , and the engaging parts  46   a  and  46   b  are engaged with the guide parts  56   a  and  56   b  of the lower case  50  as shown in  FIG. 7 , thereby assembling the upper case  40  and the lower case  50 . 
     Note that prior to assembly of the upper case  40  and the lower case  50 , at least one of an upper surface side of the vibrating plate outer circumferential portion  24   a  and the contact projection  45  of the upper case  40  may be coated with a resin such as silicone. In this case, after the third step, a sealing resin  80  as shown in  FIG. 8  is arranged on the contact portion between the piezoelectric vibrating plate  20  and the contact projection  45  by curing applied silicone with heating. This sealing resin  80  can prevent the problem of a gap being formed between the piezoelectric vibrating plate  20  and the contact projection  45 , and the problem of the piezoelectric sounding body  10  becoming unable to generate a desired sound. 
     In a fourth step, an edge of the case caulking projection  56  is heated and thereby deformed so as to be larger than a diameter of the insertion holes  46   aa  and  46   ba  formed in the engaging parts  46   a  and  46   b , whereby the upper case  40  is fixed to the lower case  50 . Moreover, when the upper case  40  is fixed to the lower case  50 , the piezoelectric vibrating plate  20  is sandwiched by the upper case  40  and the lower case  50  and fixed to the case  30 . Furthermore, by the conductive adhesive agent coated on the terminal tips  62   ca  and  72   ca  of the first conductive terminal  60  and the second conductive terminal  70  being cured after being brought into contact with the piezoelectric vibrating plate  20 , the terminal tips  62   ca  and  72   ca  and the piezoelectric vibrating plate  20  are connected. 
     After going through such steps, the piezoelectric sounding body  10  shown in  FIG. 1  is manufactured. Note that a step in which parts of the second terminal portions  64  and  74  in the first conductive terminal  60  and second conductive terminal  70  are bent upwards to configure the lateral part  64   b  shown in  FIG. 1  may be performed at the end of the first step, and moreover, may be performed in the second through fourth steps performed after the first step. 
     The piezoelectric sounding body  10  fixes the upper case  40  and the lower case  50  in a caulking manner to hold the piezoelectric vibrating plate  20  by sandwiching it between the upper case  40  and the lower case  50  (see  FIG. 7 ). The piezoelectric sounding body  10  has a high reliability because a holding state of the piezoelectric vibrating plate  20  by the case  30  is hardly changed even in the environment where vibration is frequently added or the environment where temperature variation is large. Also, the contact projection  45  of the upper case  40  presses the piezoelectric vibrating plate  20  toward the lower case  50 , and the upper case lower surface  48  is positioned with space to the piezoelectric vibrating plate  20  or the lower case  50 . This configuration allows the piezoelectric sounding body  10  to press the contact projection  45  against the piezoelectric vibrating plate  20 , prevent space from occulting between the contact projection  45  and the piezoelectric vibrating plate  20 , and improve sealing property of the contact portion between the contact projection  45  and the piezoelectric vibrating plate  20 . 
     As shown in  FIG. 8 , in the piezoelectric sounding body  10 , the lower opening  46   ab  of the insertion hole  46   aa  inserted by the caulking projection  56  is formed on the upper case lower surface  48  positioned with space to the lower case  50  or the piezoelectric vibrating plate  20 . Thus, a fixing force of the caulking fixing pressing the upper case  40  toward the lower case  50  is not directly transmitted from the upper case lower surface  48  around the insertion hole  46   aa  to the lower case  50 , but is transmitted to the piezoelectric vibrating plate  20  and the lower case  50  via the contact projection  45  next to the upper case lower surface  48 . Thus, a fixing force of the caulking fixing preferably acts in the direction where the contact projection  45  presses the piezoelectric vibrating plate  20  toward the lower case step part  51 , and sealing property of the contact portion between the contact projection  45  and the piezoelectric vibrating plate  20 . 
     As shown in  FIG. 7 , the insertion hole  46   aa  is positioned outside the contact projection  45  extending along the circumferential direction of the piezoelectric vibrating plate  20 , and a fixing force of the caulking fixing is transmitted from outside the contact projection  45  to the contact projection  45  This allows the fixing force of the caulking fixing to preferably act in a direction where the piezoelectric vibrating plate  20  held is pressed, and improve sealing property of the contact portion between the contact projection  45  and the piezoelectric vibrating plate  20 . 
     As shown in  FIG. 8 , in the piezoelectric sounding body  10 , the space “a” between the first upper case lower surface  48   a  near the contact projection  45  and the lower case  50  is configured to be larger, and the space “b” between the second upper case lower surface  48   b  far from the contact projection  45  and the lower case  50  is configured to be smaller. This allows the second upper case lower surface  48   b  to act as a stopper, and a force can be acted with good balance on the contact portion between the contact projection  45  and the piezoelectric vibrating plate  20 . Thus, the piezoelectric sounding body  10  can improve sealing property of the contact portion between the contact projection  45  and the piezoelectric vibrating plate  20 . 
     As shown in  FIG. 2  and  FIG. 3 , the piezoelectric sounding body  10  sandwiches part of the case  30  by the sandwiching portions  62   b  and  72   b  of the first and second conductive terminals  60  and  70  arranged on the inside of the case  30  and the second terminal portions  64  and  74  arranged on the outside of the case  30 . In addition, the contacting part  62   a  and the sandwiching portion  62   b  arranged on both sides sandwiching the terminal insertion holes  54   a  and  54   b  are both supported by the lower case inner wall surface  52 . As a result, an external force applied to the second terminal portions  64  and  74  is received by the case  30 , and the problem of the conductive terminals  60  and  70  moving inside the case  30  by the external force can be prevented. Thus, in the piezoelectric sounding body  10 , the problem of an electrical connection state between the piezoelectric vibrating plate  20  and the conductive terminals  60  and  70  deteriorating due to the conductive terminals  60  and  70  moving inside the case  30  by an external force, can be prevented. Moreover, even when an external force is applied, it is difficult for a fixed state of the conductive terminals  60  and  70  to the case  30  to change, and hence the piezoelectric sounding body  10  displays high reliability and durability performance. 
     Moreover, as shown in  FIG. 2 , the piezoelectric sounding body  10  has a shape that not only sandwiches the lower case  50  between the sandwiching portions  62   b  and  72   b  of the first terminal portions  62  and  72  and the downside parts  64   a  and  74   a  of the second terminal portions  64  and  74 , but sandwiches the lower case  50  also between the third terminal portions  66  and  76  and the lateral part  64   b  of the second terminal portions  64  and  74 . Thus, in the piezoelectric sounding body  10 , many portions of the conductive terminals  60  and  70 , such as the first terminal portions  62  and  72  excluding the contact-point parts  62   c  and  72   c , the second terminal portions  64  and  74 , and the third terminal portions  66  and  76 , contact the case  30  from a variety of directions, and hence an external force applied to the second terminal portions  64  and  74  is preferably received by the case  30 . 
     As shown in  FIG. 3 , in the piezoelectric sounding body  10 , the contacting parts  62   a  and  72   a  extending in the same plane as the sandwiching portions  62   b  and  72   b  are fixed to the lower case inner wall surface  52 , and hence an external force applied to the second terminal portions  64  and  74  can be preferably received by the lower case  50 . Thus, the following problem can be prevented on the inside of the case  30 , an external force is transmitted to a joining part of the contact-point parts  62   c  and  72   c  extending upwardly from the contacting parts  62   a  and  72   a  and the piezoelectric vibrating plate  20 , and the joining part is thereby damaged. Moreover, since the contacting parts  62   a  and  72   a  are fixed in a caulking manner to the lower case  50 , the lower case  50  and the contacting parts  62   a  and  72   a  are fixed with simplicity and high reliability. 
     As shown in  FIG. 3 , in the piezoelectric sounding body  10 , the conductive terminals  60  and  70  are fixed in a caulking manner by the terminal caulking projections  57   a  and  57   b  being inserted into the plurality of fixing holes  62   aa  and  72   aa  formed in the contacting parts  62   a  and  72   a , and hence the conductive terminals  60  and  70  can be effectively prevented from rotating due to an external force or the like. When attaching the conductive terminals  60  and  70  to the lower case  50 , the conductive terminals  60  and  70  can be simply arranged in a correct position merely by inserting the terminal caulking projections  57   a  and  57   b  prior to having their tips deformed, into the fixing holes  62   aa  and  72   aa  of the contacting parts  62   a  and  72   a , and hence this kind of piezoelectric sounding body  10  can be easily manufactured. 
     As shown in  FIG. 5 , in the piezoelectric sounding body  10 , the contact-point parts  62   c  and  72   c  of the conductive terminals  60  and  70  have a shape that becomes narrower toward the terminal tips  62   ca  and  72   ca . Thus, the contact-point parts  62   c  and  72   c  have a high flexibility, and conduction can be secured in a state where vibration of the piezoelectric vibrating plate  20  is unhindered. Moreover, even in the case when an external force that was unable to be received by the case  30  has been transmitted to the contact-point parts  62   c  and  72   e , the narrowed contact-point parts  62   c  and  72   c  elastically deform, whereby the external force can be prevented from being transmitted farther to the tip side than a deformed place, and the problem of damage, and so on, occurring in a joining portion between the contact-point parts  62   c  and  72   c  and the piezoelectric vibrating plate  20 , can be prevented. 
     As shown in  FIG. 5 , in the piezoelectric sounding body  10 , by the contact-point parts  62   c  and  72   c  extending in a direction intersecting the first direction, a length from the portion fixed in a caulking manner to the terminal tips  62   ca  and  72   ca  can be increased, whereby appropriate springiness can be provided to the contact-point part  62   c . Moreover, the problem of the terminal caulking projections  57   a  and  57   b  interfering with a movable range of the contact-point parts  62   c  and  72   c  to cause a defective product, can be reduced. 
     As shown in  FIG. 6 , the third terminal portions  66  and  76  of the conductive terminals  60  and  70  have formed therein the through hole  66   a  corresponding to a shape of the sandwiching portions  62   b  and  72   b , and such conductive terminals  60  and  70  can be easily formed by mechanically processing a single metal plate. Such conductive terminals  60  and  70  do not have a joining portion resulting from the likes of welding or adhesion, hence have high strength and excellent durability. 
     As above, the piezoelectric sounding body according to the present invention was described showing an embodiment. However, the technical scope of the present invention is not limited to the piezoelectric sounding body  10  according to the embodiment, and it goes without saying that various modified examples altering the configuration of part of the piezoelectric sounding body  10  are also included in the technical scope of the invention. For example, shapes of the upper case  40  and the lower case  50 , shapes of the conductive terminals  60  and  70 , the numbers and positions of the terminal caulking projections  57   a  and  57   b , and so on, can be changed according to design conditions, and so on. 
     In addition, for example, relative positions of the first terminal insertion hole  54   a  and the terminal caulking projection  57   a  and relative positions of the second terminal insertion hole  54   b  and the terminal caulking projection  57   b  may be made different. In this case, formation positions of the fixing holes  62   aa  and  72   aa  in the conductive terminals  60  and  70  are also made different for the first conductive terminal  60  and the second conductive terminal  70 , based on the relative positions of the terminal insertion holes  54   a  and  54   b  and the terminal caulking projections  57   a  and  57   b . By adopting such a shape, the problem that during assembly, the first conductive terminal  60  and the second conductive terminal  70  end up being assembled arranged in a mistaken position, can be prevented. 
     DESCRIPTION OF THE NUMERALS 
     
         
           10  . . . piezoelectric sounding body 
           20  . . . piezoelectric vibrating plate 
           22  . . . piezoelectric body 
           22   a  . . . other electrode 
           24  . . . vibrating plate 
           30  . . . case 
           40  . . . upper case 
           42  . . . sound emitting hole 
           44  . . . cylindrical part 
           45  . . . contact projection 
           46   a ,  46   b  . . . engaging part 
           46   aa ,  46   ba  . . . insertion hole 
           48  . . . upper case lower surface 
           48   a  . . . first upper case lower surface 
           48   b  . . . second upper case lower surface 
           50  . . . lower case 
           50   a  . . . center 
           51  . . . lower case step part 
           52  . . . lower case inner wall surface 
           53  . . . lower case outer wall surface 
           53   a  . . . downside recess 
           53   b  . . . lateral recess 
           54   a ,  54   b  . . . terminal insertion hole 
           56  . . . case caulking projection 
           56   a ,  56   b  . . . guide part 
           57   a ,  57   b  . . . terminal caulking projection 
           58   a ,  58   b  . . . auxiliary caulking projection 
           59  . . . notch 
           60 ,  70  . . . conductive terminal 
           62 ,  72  . . . first terminal portion 
           62   a  . . . contacting part 
           62   aa ,  72   aa  . . . fixing hole 
           62   b  . . . sandwiching portion 
           62   c  . . . contact-point part 
           62   ca ,  72   ca  . . . terminal edge 
           64 ,  74  . . . second terminal portion 
           64   a  . . . downside part 
           64   h  . . . lateral part 
           66  . . . third terminal portion 
           66   a  . . . through hole 
           80  . . . sealing resin