| 摘要 |
PURPOSE:To prevent a diaphragm from curving and to stabilize sound pressure frequency characteristics by tapering the peripheral edge part of the diaphragm and arranging it at one end of a resin case so that an opening is covered, and caulking and fixing the peripheral edge part from above and below. CONSTITUTION:The entire peripheral edge part 23a of the diaphragm 23 on the opposite side from the side where a piezoelectric element 22 is stuck is tapered outwardly radially. Further, the resin case 21 has a bottom part 21a and a side wall 21b and a caulking fixation part 25 is formed at the upper end part of the side wall 21. The tapered peripheral edge part 23a of the diaphragm 23 is caulked and fixed with the caulking fixation part 25. The diaphragm is therefore pressed in the thickness direction by the peripheral edge part and fixed and no undesired pressing force which operates on the center part from the outer peripheral surface is generated. Consequently, the diaphragm never curves and the stable sound pressure frequency characteristics are obtained. |
