Structure of lead-free piezoelectric ceramic buzzer

Abstract

The utility model discloses a structure of a lead-free piezoelectric ceramic buzzer, which comprises a bottom shell, an upper cover arranged at the upper part of the bottom shell, a piezoelectric plate arranged in an inner cavity between the bottom shell and the upper cover, the bottom of the piezoelectric plate arranged on an inner boss of the bottom shell, the edge of the upper cover arranged in an inner wall groove at the upper end of the bottom shell, a small inner groove arranged at the upper end of the inner wall groove, and a small inner groove arranged at the lower end of the inner wall groove. A small inner groove is formed in the inner wall groove, a small boss is arranged at the top of the upper cover edge and placed in the small inner groove, an outer fillet is arranged on the upper edge of the inner wall groove, an inner fillet is arranged on the outer edge of the small inner groove, a copper substrate is arranged at the bottom of the piezoelectric plate, a piezoelectric ceramic layer is arranged on the upper portion of the piezoelectric plate, and the piezoelectric ceramic layer is made of lead-free materials.

Description

Structure of a lead-free piezoelectric ceramic buzzer Technical Field

[0001] This utility model relates to the field of electronic components, and in particular to the field of buzzers used in electrical appliances. Background Technology

[0002] Piezoelectric buzzers, commonly used in electrical appliances, are a type of electronic component that serves to emit warning sounds. In traditional designs, piezoelectric buzzers consist of three main parts: a base, a top cover, and a piezoelectric element. When the top cover is installed in a groove on the base, the elasticity of the plastic can cause it to pop out of the groove under external force. Furthermore, conventional piezoelectric buzzers use a copper base with a ceramic layer, and then a silver or graphene layer on top of that ceramic layer to achieve conductivity. If the ceramic layer is made of lead-containing material, it can be detrimental to environmental protection and cause serious pollution. Summary of the Invention

[0003] To address the aforementioned issues, this invention provides a structure for a lead-free piezoelectric ceramic buzzer. The buzzer includes a bottom shell, with a top cover on its upper part. A piezoelectric element is disposed within the cavity between the bottom shell and the top cover. The bottom of the piezoelectric element rests on an inner protrusion of the bottom shell, with a circular through-hole at its center to facilitate sound transmission. The edge of the top cover is placed within an inner wall groove at the upper end of the bottom shell. A small inner groove is located at the upper end of the inner wall groove, and a small protrusion is located at the top of the edge of the top cover. This small protrusion, placed within the small inner groove, prevents the top cover from detaching from the inner wall groove of the bottom shell, providing a double anti-detachment function.

[0004] Furthermore, the upper edge of the inner wall groove is provided with an outer rounded corner.

[0005] Furthermore, the outer edge of the small inner groove is provided with an inner rounded corner.

[0006] Preferably, the bottom of the piezoelectric sheet is a copper substrate, the top is a piezoelectric ceramic layer, and a silver layer or a graphene layer is disposed on the top of the piezoelectric ceramic layer.

[0007] Preferably, the piezoelectric ceramic layer is made of lead-free material, and the main system of lead-free piezoelectric ceramic includes the following:

[0008] A. Barium titanate-based lead-free piezoelectric ceramics

[0009] B.BNT-based lead-free piezoelectric ceramics

[0010] C. Bismuth-layered piezoelectric ceramics

[0011] D. Niobate-based lead-free piezoelectric ceramics

[0012] By using the above-mentioned utility model solution, the piezoelectric ceramic layer on the piezoelectric element in the piezoelectric ceramic buzzer is changed from lead-containing to lead-free, which will improve environmental protection and avoid lead pollution. At the same time, adding a small protrusion to the top cover and fastening the small protrusion into the small inner groove in the inner wall groove of the bottom shell can better prevent the possibility of the top cover falling off, improve the reliability of the product, optimize the product structure, and significantly improve the quality assurance and lifespan of the product. Attached Figure Description

[0013] The following detailed description, in conjunction with the accompanying drawings and embodiments of the utility model, will be provided.

[0014] Figure 1 shows a cross-sectional view of the present invention.

[0015] Figure 2 shows a three-dimensional schematic diagram of the present invention after assembly.

[0016] Figure 3 shows a magnified schematic diagram of a portion of the present invention. Detailed Implementation

[0017] As shown in Figures 1-3, the specific content of this utility model is described in detail below with reference to an embodiment: A structure of a lead-free piezoelectric ceramic buzzer includes a bottom shell 2, an upper cover 1 on the upper part of the bottom shell 2, a piezoelectric sheet 3 in the inner cavity between the bottom shell 2 and the upper cover 1, the bottom of the piezoelectric sheet 3 being placed on an inner boss 25 of the bottom shell 2, a circular through hole being provided in the center of the inner boss 25 to facilitate sound transmission from the hole, the edge of the upper cover being placed in an inner wall groove 21 at the upper end of the bottom shell, a small inner groove 22 being provided at the upper end of the inner wall groove 21, and a small boss 121 being provided at the top of the edge of the upper cover, the small boss 121 being placed in the small inner groove 22 to prevent the upper cover 1 from coming out of the inner wall groove 21 of the bottom shell 2, thus achieving a double anti-coming-out effect.

[0018] In an embodiment of this utility model, the upper edge of the inner wall groove 21 is provided with an outer rounded corner 24. This rounded corner can effectively decompose the mold stress and reduce the resistance when the upper cover 1 is pressed into the small inner groove 22 on the inner wall groove 21 by mechanical force, so that the small protrusion 121 can smoothly enter the small inner groove 22 without being damaged.

[0019] In an embodiment of this utility model, the outer edge of the small inner groove 22 is provided with an inner rounded corner 23. This rounded corner can effectively reduce the resistance when the upper cover 1 is pressed into the inner wall groove 21 of the bottom shell by mechanical force, and can allow the upper cover 1 to smoothly enter the inner wall groove 21 without damage.

[0020] In a preferred embodiment of this utility model, the bottom of the piezoelectric sheet is a copper substrate 31, and the upper part is a piezoelectric ceramic layer 32, wherein a silver layer or a graphene layer is disposed on the top of the piezoelectric ceramic layer 32.

[0021] In a preferred embodiment of this invention, the piezoelectric ceramic layer 32 is made of lead-free material, and the main system of lead-free piezoelectric ceramic includes the following:

[0022] A. Barium titanate-based lead-free piezoelectric ceramics

[0023] B.BNT-based lead-free piezoelectric ceramics

[0024] C. Bismuth-layered piezoelectric ceramics

[0025] D. Niobate-based lead-free piezoelectric ceramics

[0026] While traditional piezoelectric ceramics have many outstanding advantages, their main component, lead oxide (PbO) (containing more than 60-70%), is a volatile and toxic substance. The sintering temperature is generally above 1200℃, which often causes deviations in the stoichiometry of lead zirconate titanate (PZT) ceramics, making it difficult to control their performance stably. This can easily cause environmental pollution and, in severe cases, endanger the health of humans and other organisms.

[0027] The purpose of developing the aforementioned lead-free ceramics is for researchers to strive to obtain piezoelectric ceramics that have both satisfactory performance and good environmental compatibility. The material system itself must not contain substances that may have a harmful impact on the ecological environment, and no substances that may be harmful to the environment should be generated during the preparation, use and disposal process.

[0028] In the embodiments of this utility model, the piezoelectric ceramic layer 32 in the piezoelectric sheet 3 is bonded to the copper base sheet 31 with adhesive. The upper cover 1 is provided with two pins 11, which are positive and negative. One end of the pin 11 is exposed beyond the upper cover 12 for a certain length, and the other end is bent to form an elastic contact with different poles of the piezoelectric sheet 3. When energized, the piezoelectric sheet 3 vibrates and emits sound under the action of current. The above description of the basic structure and function of the piezoelectric buzzer is the prior art that has been disclosed and will not be described in detail here.

[0029] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. For those skilled in the art, the present utility model can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A structure for a lead-free piezoelectric ceramic buzzer, comprising a bottom shell, an upper cover disposed on the upper part of the bottom shell, a piezoelectric sheet disposed in the inner cavity between the bottom shell and the upper cover, the bottom of the piezoelectric sheet being placed on an inner protrusion of the bottom shell, and the edge of the upper cover being placed in a groove in the inner wall of the upper end of the bottom shell, characterized in that... The upper end of the inner wall groove is provided with a small inner groove, and the top edge of the upper cover is provided with a small protrusion, which is placed in the small inner groove.

2. The structure of a lead-free piezoelectric ceramic buzzer according to claim 1, wherein: The upper edge of the inner wall groove is provided with an outer rounded corner.

3. The structure of a lead-free piezoelectric ceramic buzzer according to claim 1, characterized in that: The outer edge of the small inner groove is provided with an inner rounded corner.

4. The structure of a lead-free piezoelectric ceramic buzzer according to claim 1, characterized in that: A circular through hole is provided at the center of the inner boss.

5. The structure of a lead-free piezoelectric ceramic buzzer according to claim 1, characterized in that: The bottom of the piezoelectric sheet is a copper substrate, and the top is a piezoelectric ceramic layer. A silver layer or a graphene layer is disposed on the top of the piezoelectric ceramic layer.

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