JPH0540558Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention improves the structure and mounting position of the connection pin of a piezoelectric buzzer integrated with a case.

[Conventional technology]

Case-integrated piezoelectric buzzers, which are incorporated into various electronic devices, are generally as shown in Figure 4.
A piezoelectric element 1, which has electrodes formed on both main surfaces of a disc-shaped piezoelectric ceramic and a large circular diaphragm attached to one of the main surfaces, is inserted from the cap 2a and the bottom plate 2b with the diaphragm side facing up. A pair of connecting pins 3 and 4 for electrically connecting to the piezoelectric element are provided on the bottom plate 2b of the case.

These pair of connecting pins each consist of a lead part 3a and a contact piece 3b, and a lead part 4a and a contact piece 4b, and as shown in FIG. They are positioned at equal distances from the center on a straight line passing through the center of the portion of the piezoelectric ceramic corresponding to the shape of the electrode, and are fixed to prevent displacement. Furthermore, these pair of connecting pins are
Each contact piece 3b, 4b is bent in a predetermined direction at its base end, one contact piece 3b is brought into contact with a vibration node position of the electrode formed on the piezoelectric ceramic, and the other contact piece 3b is bent in a predetermined direction at its base end. 4b is in contact with the diaphragm.

In such a case-integrated piezoelectric buzzer, an electrical signal supplied through the connecting pin is converted into mechanical vibration to generate sound.

There are many ways to use such a case-integrated piezoelectric buzzer, and the sound you want to generate, that is, the vibration frequency, varies depending on the purpose and use of the piezoelectric buzzer. , the piezoelectric element can be changed depending on its purpose.

[Problem to be solved by the invention]

However, with the conventional structure described above, the contact position of the tip of the contact piece of the connecting pin is fixed depending on the fixed position and direction of the connecting pin and the length of the contact piece, so the piezoelectric elements accommodated are different. A misalignment occurred between the position of the vibration node and the contact position of the contact piece, making it impossible to obtain the desired vibration frequency or sufficient sound pressure.

Therefore, in order to accommodate piezoelectric elements in various frequency ranges with different positions of vibration nodes, it is necessary to create cases with different fixed positions and directions of the connection pins on the bottom plate of the case, different lengths of the contact pieces, etc. There is a problem in that one case cannot be shared with piezoelectric elements in other frequency ranges, and it has been desired to develop a piezoelectric buzzer with a structure that can be used efficiently.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention provides a piezoelectric element having a piezoelectric ceramic, an electrode, and a diaphragm, a case that houses this piezoelectric element, and a piezoelectric element that is attached to the case and includes the piezoelectric ceramic electrode and diaphragm. In a piezoelectric buzzer having a pair of connecting pins each having a contact piece in contact with the piezoelectric buzzer, a base end of the contact piece of one of the pair of connecting pins corresponds to the shape of the piezoelectric ceramic electrode of the case. To provide a piezoelectric buzzer which is attached and fixed to a central part of a part, and whose contact piece is curved outward from the central part so that the degree of curvature can be changed, and whose tip is formed as a free end.

[Effect]

One of the connecting pins is fixed to the center of the piezoelectric ceramic part of the case that corresponds to the electrode shape, and the contact piece is curved toward the outer circumference so that the degree of curvature of the contact piece can be changed. This allows the piezoelectric element to be brought into contact with any position in the radial direction, and the contact piece can be brought into contact with different piezoelectric elements at the vibration node positions thereof.

〔Example〕

Next, one embodiment of the present invention will be described based on FIGS. 1 to 3.

In the figure, reference numeral 11 is a piezoelectric element, in which slightly smaller and same-shaped electrodes 11b and 11'b are formed on both sides of a disc-shaped piezoelectric ceramic 11a, and one of the electrodes 11b has a circular shape larger than the piezoelectric ceramic. A metal diaphragm 11c is attached.

12 is a plastic case with cap 1
2a and a bottom plate 12b, a step is provided at the center of the inner periphery of the cap 12a, and a thin section is formed from there to the lower end, and the edge of the diaphragm 11c of the piezoelectric element 11 is attached to this step. touched,
Furthermore, the cap 12a and the bottom plate 12b are sandwiched by a side wall 12b-1 protruding from the bottom plate 12b, and in this state, the inner and outer peripheral surfaces of the cap 12a and the bottom plate 12b are fixed to each other by pressure contact due to the elasticity of the cap.

13 and 14 are connecting pins, which are integrally formed by punching a metal plate, and one connecting pin 1
3 consists of a lead part 13a and a contact piece 13b, and the other connecting pin 14 consists of a lead part 14a and a contact piece 14b, and the intermediate part of each is embedded and fixed in the bottom plate 12b. As shown in FIG. 3, the intermediate portions of these connecting pins are fixed in positions such that the intermediate portion of one connecting pin is in the center of the bottom plate, and the intermediate portion of the other connecting pin is on a straight line passing through the center of the bottom plate. Further, one contact piece 13b is curved toward the outer circumferential direction, and its apex is in contact with the electrode 11'b of the piezoelectric element, and the other contact piece 14b is bent at its base end and then straightened. It extends into a shape, and its tip is in contact with the diaphragm 11c.

In this state, when an electric signal is input to the lead parts 13a and 14a, a signal voltage is applied to the electrode 11b via the electrode 11'b and the diaphragm 11c, and accordingly, the piezoelectric ceramic 11a is Mechanical vibrations are caused, which causes the diaphragm to vibrate and generate sound. At this time, the apex of the contact piece 13b is brought into contact with a portion of the electrode corresponding to the node of the vibration frequency.

A piezoelectric buzzer can be used in this way, but if you want to change the sound generated, prepare a piezoelectric element with a vibration frequency corresponding to the sound, enlarge the lower end of the cap of the case, remove the bottom plate, The piezoelectric element 11 is taken out. Next, the contact piece 13b is deformed to change its degree of curvature so that its apex contacts the position of the vibration frequency node of the replaced piezoelectric element. After that, the prepared piezoelectric element is assembled into the case in the same manner as above, and each contact piece 13b, 14
When b is brought into contact with the electrode 11'b and the diaphragm 11c, a piezoelectric buzzer with different vibration frequencies is completed.

[Effect of idea]

According to the present invention, the base end of the contact piece of one connecting pin is fixed to the center part of the case corresponding to the piezoelectric ceramic electrode, and the contact piece that contacts the electrode is formed in a curved manner. Since the degree can be changed, the contact position with the electrode can be changed by changing only the degree of curvature of the contact piece of the connecting pin attached to the case housing the piezoelectric element. This makes it possible to use the same case and simply change the piezoelectric element with a different vibration frequency to bring the contact piece into contact with the node of that vibration frequency.One case can be shared by many different piezoelectric elements, making effective use of the case. It is possible to improve the economical efficiency and ease of handling.

In addition, since the base end of the contact piece of one of the connecting pins is fixed to the above-mentioned center part of the case, when fixing the connecting pin or incorporating a piezoelectric element into the case, for example, it is necessary to Even if lateral displacement occurs due to the stress applied, the concentric circles of the nodes of the vibration frequency of the piezoelectric element and the concentric circles of the lateral displacement of the contact piece are centered, and the contact position between the contact piece and the electrode ends up being the same as that of the piezoelectric element. The desired vibration frequency and sufficient sound pressure can be obtained without deviation from the node of the vibration frequency.

[Brief explanation of the drawing]

Fig. 1 is a front longitudinal cross-sectional view of a piezoelectric buzzer according to an embodiment of the present invention, Fig. 2 is a right-hand longitudinal cross-sectional view thereof, Fig. 3 is a plan view of the bottom plate of the piezoelectric buzzer to which the connecting pin is fixed, and Fig. 4 The figure is a longitudinal sectional view of a conventional piezoelectric buzzer, and FIG. 5 is a plan view of the bottom plate of the case to which the connection pins are fixed. In the figure, 1 and 11 are piezoelectric elements, 11a is a piezoelectric ceramic, 11b and 11'b are electrodes, 11c is a diaphragm, 2 and 12 are cases, 2a and 12a are case caps, 2b and 12b are case bottom plates, 3, 4,1
3 and 14 are connection pins, 3a, 13a, 4a, 14
a is a lead portion, and 3b, 4b, 13b, and 14b are contact pieces.

Claims (1)

[Scope of utility model registration request] A piezoelectric element having a piezoelectric ceramic, an electrode, and a diaphragm, a case accommodating the piezoelectric element, and a pair of connecting pins each having a contact piece attached to the case and contacting the electrode and diaphragm of the piezoelectric ceramic, respectively. In the piezoelectric buzzer, a base end of a contact piece of one of the pair of connection pins is attached and fixed to the center of a portion of the case corresponding to the shape of the piezoelectric ceramic electrode, and the contact piece is A piezoelectric buzzer characterized in that it is curved so that the degree of curvature can be changed from the center toward the outside, and the tip is formed as a free end.