Vibration sensor

Abstract

The utility model discloses a vibration sensor, which comprises a shell, a circuit board and a piezoelectric ceramic piece, the piezoelectric ceramic piece is electrically connected with the circuit board, the piezoelectric ceramic piece is fixedly connected to the inner surface of the shell, the shell is provided with a first through hole, and the first through hole is communicated with the circuit board. And at least one part of the first through hole is covered by the orthographic projection of the piezoelectric ceramic piece on the shell. According to the utility model, vibration signals are concentrated in the piezoelectric ceramic piece area to be locally enhanced, and the larger the signals sensed by the piezoelectric ceramic piece are, the higher the signal intensity is.

Description

Technical Field

[0001] The utility model relates to a vibration sensor, belonging to the technical field of mechanical vibration measurement. Background Art

[0002] Vibration impact sensors have been widely used in fields such as safe transportation. Vibration sensors can effectively identify potential safety hazards, help users detect risks in a timely manner, and perform repairs, maintenance, etc. in advance; vibration sensors can effectively collect information on users' usage habits, feedback to users in a timely manner, and improve their usage safety performance; it is particularly important for vibration sensors to be able to effectively identify the magnitude of vibration and the starting point of vibration, and avoid the occurrence of risks in advance.

[0003] In the prior art, the piezoelectric ceramics used in vibration sensors are usually directly installed on the bottom plate carrier and encapsulated in the product shell. For the processing of vibration signals, it is usually enhanced through a signal amplification circuit, which belongs to the method of post-processing after acquisition. However, for weak vibrations, the piezoelectric ceramics may be difficult to output effective signals, and the electrical signals may also be interfered by other signals, etc. Summary of the Utility Model

[0004] Aiming at the above-mentioned defects of the prior art, the task of the utility model is to provide a vibration sensor, aiming to enhance the detection sensitivity to weak vibration signals.

[0005] The technical solution of the utility model is as follows: A vibration sensor includes a shell, a circuit board, and a piezoelectric ceramic sheet. The piezoelectric ceramic sheet is electrically connected to the circuit board. The piezoelectric ceramic sheet is fixedly connected to the inner surface of the shell. The shell is provided with a first through hole, and at least a part of the first through hole is covered by the orthographic projection of the piezoelectric ceramic sheet on the shell.

[0006] Further, the piezoelectric ceramic sheet is welded to the circuit board.

[0007] Further, the first through hole is a strip-shaped hole, and the strip-shaped hole crosses the covering area of the piezoelectric ceramic sheet on the shell.

[0008] Further, the first through hole is located between the positive and negative electrodes of the piezoelectric ceramic sheet.

[0009] Further, the piezoelectric ceramic sheet is bonded to the inner surface of the shell.

[0010] Further, a rigid-flexible composite board is provided between the piezoelectric ceramic sheet and the shell. The piezoelectric ceramic sheet is fixedly connected to the first surface of the rigid-flexible composite board. The second surface of the rigid-flexible composite board is fixedly attached to the shell. The rigid-flexible composite board is provided with a second through hole, and at least a part of the second through hole is covered by the orthographic projection of the piezoelectric ceramic sheet on the rigid-flexible composite board.

[0011] Further, the second through hole has the same shape as and overlaps with the first through hole.

[0012] Further, the second through hole is a strip-shaped hole that crosses the covered area of the piezoelectric ceramic sheet on the rigid-flexible composite board.

[0013] Further, the second through hole is located between the positive and negative electrodes of the piezoelectric ceramic sheet.

[0014] The advantages of the present utility model compared with the prior art are as follows:

[0015] The piezoelectric ceramic sheet is connected to the outer shell, and a first through hole is opened in the area covered by the piezoelectric ceramic sheet on the outer shell. The external vibration signals conducted through the outer shell will be concentrated on both sides of the first through hole instead of being evenly distributed on the outer shell. Therefore, the vibration signals conducted to the piezoelectric ceramic sheet are enhanced, the signals sensed by the piezoelectric ceramic sheet are increased, and finally the output signal intensity is enhanced, improving the sensitivity to weak signals.

[0016] The piezoelectric ceramic sheet is directly welded to the circuit board to achieve electrical connection. Compared with the previous vibration sensors with a split design that require wires and wire harnesses to connect terminals for transfer, the wire harness is saved, the signal transmission distance is shortened, the signal transmission response is faster, and it also has better anti-interference performance.

[0017] A rigid-flexible composite board is provided between the piezoelectric ceramic sheet and the outer shell for conducting vibration signals, which can adjust the height of the piezoelectric ceramic sheet, enhance the signal, and meet the requirements of different circuit board installation positions at the same time. Description of the Drawings

[0018] Figure 1 It is an exploded structural schematic diagram of the vibration sensor of the embodiment.

[0019] Figure 2 It is a longitudinal sectional structural schematic diagram of the vibration sensor of the embodiment.

[0020] Figure 3 It is a positional structural schematic diagram among the outer shell, the rigid-flexible composite board, and the piezoelectric ceramic sheet in the vibration sensor of the embodiment.

[0021] Figure 4 It is a positional relationship schematic diagram between the piezoelectric ceramic sheet and the first through hole and the second through hole in the vibration sensor of the embodiment. Detailed Embodiments

[0022] The present utility model will be further described below in conjunction with embodiments, but it is not limited to the present utility model.

[0023] Please refer to Figures 1 to 4As shown in the figure, a vibration sensor involved in this embodiment mainly includes a housing, a rigid-flex printed circuit board 1, a piezoelectric ceramic sheet 2, and a circuit board 3. The housing consists of a bottom case 4 and a cover 5. The bottom case 4 has an installation cavity 4a for installing the rigid-flex printed circuit board 1, the piezoelectric ceramic sheet 2, and the circuit board 3. The cover 5 is covered on the bottom case 4 to enclose the installation cavity 4a. At the same time, the cover 5 also has a plug 5a for transmitting signals to the outside, and the plug 5a is electrically connected to the corresponding output circuit on the circuit board 3 through a lead wire.

[0024] In this embodiment, the bottom case 4 is a square housing. A first through hole 4b is opened on the bottom surface of the bottom case 4. The first through hole 4b is a strip-shaped hole, and the bottom surface of the piezoelectric ceramic sheet 2 can be adhesively fixed on the bottom surface of the bottom case 4. In this embodiment, in order to control the device height of the piezoelectric ceramic sheet 2 and ensure that the vibration signal is strengthened, a rigid-flex printed circuit board 1 is adhesively fixed on the bottom surface of the bottom case 4. The front and back surfaces of the rigid-flex printed circuit board 1 are the first surface and the second surface respectively. The second surface of the rigid-flex printed circuit board 1 is adhesively fixed to the bottom surface of the bottom case 4, and the piezoelectric ceramic sheet 2 is adhesively fixed to the first surface of the rigid-flex printed circuit board 1. The circuit board 3 is then welded and fixed to the piezoelectric ceramic sheet 2 for electrical connection. The rigid-flex printed circuit board 1 can be made of the same PCB board as the circuit board 3. A second through hole 1a is opened on the rigid-flex printed circuit board 1. The orthographic projection of the piezoelectric ceramic sheet 2 on the rigid-flex printed circuit board 1 should cover at least a part of the second through hole 1a, and the orthographic projection of the piezoelectric ceramic sheet 2 on the bottom case 4 should cover at least a part of the first through hole 4b. In this embodiment, the second through hole 1a is processed into a strip-shaped hole with the same shape and size as the first through hole 4b. When the rigid-flex printed circuit board 1 is fixedly adhered, the second through hole 1a and the first through hole 4b are overlapped. When the piezoelectric ceramic sheet 2 is fixed, the strip-shaped hole passes through the piezoelectric ceramic sheet 2, and the positive and negative electrodes of the piezoelectric ceramic sheet 2 are located on both sides of the second through hole 1a.

[0025] In this embodiment, by using the first through hole 4b and the second through hole 1a, the conduction of the vibration signal in the housing and the rigid-flex printed circuit board 1 is non-uniform, but is strengthened around the first through hole 4b and the second through hole 1a, so as to increase the signal sensed by the piezoelectric ceramic sheet 2 to achieve high-sensitivity sensing of weak vibration signals. Therefore, it can be understood that in some embodiments, the first through hole 4b and the second through hole 1a can also be made into round holes, as long as it is ensured that the piezoelectric ceramic sheet 2 covers at least a part of the first through hole 4b and the second through hole 1a.

Claims

1. A vibration sensor, comprising a housing, a circuit board and a piezoelectric ceramic sheet, characterized in that The piezoelectric ceramic sheet is electrically connected to the circuit board, the piezoelectric ceramic sheet is fixedly connected to the inner surface of the housing, a first through hole is provided on the housing, and at least a part of the first through hole is covered by the orthographic projection of the piezoelectric ceramic sheet on the housing.

2. The vibration sensor according to claim 1, characterized in that, The piezoelectric ceramic sheet is connected to the circuit board by soldering.

3. The vibration sensor according to claim 1, wherein The first through hole is a strip-shaped hole, and the strip-shaped hole crosses the covering area of the piezoelectric ceramic sheet on the housing.

4. The vibration sensor according to claim 3, characterized in that, The first through hole is located between the positive and negative electrodes of the piezoelectric ceramic sheet.

5. The vibration sensor according to claim 1, characterized in that, The piezoelectric ceramic sheet is bonded to the inner surface of the housing.

6. The vibration sensor according to claim 1, characterized in that A rigid-flexible composite board is provided between the piezoelectric ceramic sheet and the housing. The piezoelectric ceramic sheet is fixedly connected to the first surface of the rigid-flexible composite board. The second surface of the rigid-flexible composite board is fixedly attached to the housing. A second through hole is provided on the rigid-flexible composite board, and at least a part of the second through hole is covered by the orthographic projection of the piezoelectric ceramic sheet on the rigid-flexible composite board.

7. The vibration sensor according to claim 6, wherein The second through hole has the same shape as and overlaps with the first through hole.

8. The vibration sensor according to claim 7, wherein The second through hole is a strip-shaped hole, and the strip-shaped hole crosses the covering area of the piezoelectric ceramic sheet on the rigid-flexible composite board.

9. The vibration sensor according to claim 8, characterized in that The second through hole is located between the positive and negative electrodes of the piezoelectric ceramic sheet.

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