An ultrasonic sensor structure with improved detection range

Abstract

The utility model provides an ultrasonic sensor structure of promoting detection distance, including shell, the utility model discloses the cooperation structure of coating piece and mounting bracket effectively guaranteed the free vibration state of piezoelectric ceramic piece in foamed colloid filling environment, mounting bracket and piezoelectric ceramic piece do not contact each other, and the piezoelectric ceramic piece of mounting rack top hollow portion inserts the coating piece and ceramic piece top and sticks together but does not produce rigid restraint, make the radial vibration of ceramic piece not be restrained by any solid structure's clamping or bonding, and coating piece will foamed colloid and ceramic piece completely isolate, avoid the damping effect that foamed colloid solidification and ceramic piece surface bonding produce, make ceramic piece can vibrate freely with maximum amplitude, and the electric energy is converted into sound energy and radiates outward with maximum limit, and coating piece as sound matching layer can also reduce the sound wave reflection loss caused by sound impedance difference, further promote sound energy transmission efficiency.

Description

Technical Field

[0001] This utility model mainly relates to the field of ultrasonic sensor technology, specifically to an ultrasonic sensor structure that improves detection distance. Background Technology

[0002] An ultrasonic sensor is an acoustic device that utilizes the piezoelectric effect of a piezoelectric ceramic element to convert electrical energy into sound energy. Its core function is to transmit and receive ultrasonic signals. During operation, an external circuit applies an electrical signal, causing the piezoelectric ceramic element to vibrate mechanically and radiate ultrasonic waves. When an echo is received, the piezoelectric ceramic element converts the sound wave vibration into an electrical signal output. Ultrasonic sensors are widely used in distance measurement, object detection, and liquid level monitoring, offering advantages such as non-contact operation, fast response, and low cost. Their detection distance and sensitivity are primarily determined by the vibration amplitude and efficiency of the piezoelectric ceramic element.

[0003] Existing ultrasonic sensors commonly use expanding foam as a sound-absorbing material to fill the inner cavity of the housing. During injection and curing, the expanding foam directly covers the surface of the piezoelectric ceramic sheet and bonds with it. Because the expanded foam has a certain rigidity and adhesion after curing, when the piezoelectric ceramic sheet vibrates radially during operation, the foam bonded to it will dampen and suppress the vibration of the ceramic sheet, consuming and weakening the vibration energy of the ceramic sheet. This results in a significant limitation on the amplitude of the ceramic sheet, making it impossible to reach the designed maximum vibration amplitude. Consequently, the acoustic wave transmission power of the ultrasonic sensor decreases, and the detection distance cannot meet the growing application requirements. At the same time, the mounting brackets or support components of existing sensors are mostly in direct contact with the piezoelectric ceramic sheet during assembly, and are fixed by adhesive or compression, which further increases the mechanical constraint on the vibration of the ceramic sheet and aggravates the loss of vibration energy. In addition, the internal components of existing sensors lack precise positioning and guiding structures during assembly. The installation position is prone to deviation due to manual operation, resulting in poor consistency of the relative positions between components. This not only affects the stability of product performance but also reduces production efficiency and yield. Utility Model Content

[0004] This invention mainly provides an ultrasonic sensor structure that improves detection distance, in order to solve the technical problems mentioned in the background art.

[0005] The technical solution adopted by this utility model to solve the above-mentioned technical problems is as follows: An ultrasonic sensor structure for improving detection range includes a housing, an oscillator support assembly on the inner bottom wall of the housing, an easy-assembly assembly on the surface of the inner bottom wall of the housing, and the interior of the housing is filled with foamed colloid.

[0006] Preferably, the oscillator bearing assembly includes a piezoelectric ceramic sheet, a mounting frame, and a coating sheet. The piezoelectric ceramic sheet is provided on the bottom wall of the housing, and the mounting frame is provided above the piezoelectric ceramic sheet. The top of the mounting frame is provided with a coating sheet.

[0007] Preferably, a gap is left between the outer wall of the piezoelectric ceramic sheet and the inner wall of the mounting bracket, and the bottom of the coating sheet is attached to the top of the piezoelectric ceramic sheet.

[0008] Preferably, both conductive electrode layers of the piezoelectric ceramic sheet are fixedly connected to conductive leads, and both conductive leads pass through the coating sheet and the foamed colloid in sequence to connect to the external circuit.

[0009] Preferably, the easy-to-assemble component includes an assembly groove and an assembly strip. The assembly groove is provided on both sides of the inner bottom wall surface of the outer shell, and an assembly strip is assembled inside each of the two assembly grooves. The top ends of the two assembly strips are respectively fixedly connected to the bottom sides of the mounting bracket.

[0010] Preferably, the top of the mounting frame has a hollow structure, the coating sheet is embedded in the hollow part of the mounting frame, and the edge of the coating sheet is fixedly connected to the inner wall of the hollow structure of the mounting frame.

[0011] Compared with the prior art, the beneficial effects of this utility model are as follows: 1. The cooperative structure of the coating sheet and the mounting bracket effectively ensures the free vibration state of the piezoelectric ceramic sheet in the foamed colloid filling environment. The mounting bracket and the piezoelectric ceramic sheet do not contact each other. The coating sheet embedded in the hollowed-out part of the mounting bracket fits with the top of the ceramic sheet but does not create rigid constraints. This ensures that the radial vibration of the ceramic sheet is not suppressed by any solid structure clamping or bonding. At the same time, the coating sheet completely isolates the foamed colloid from the ceramic sheet, avoiding the damping effect caused by the adhesion of the foamed colloid to the surface of the ceramic sheet after curing. This allows the ceramic sheet to vibrate freely with maximum amplitude, converting electrical energy into sound energy for maximum outward radiation. Meanwhile, the coating sheet, as an acoustic matching layer, can also reduce the sound wave reflection loss caused by the difference in acoustic impedance, further improving the sound energy transmission efficiency. This allows the sensor to obtain a longer detection distance and higher echo sensitivity under the same driving voltage.

[0012] 2. By forming a sliding fit between the assembly groove on the bottom wall of the outer shell and the assembly strip fixed at the bottom of the mounting bracket, the mounting bracket can be quickly positioned and accurately installed inside the outer shell. The assembly groove and assembly strip have guiding and limiting functions during the assembly process, so that the mounting bracket is kept at a consistent height relative to the piezoelectric ceramic sheet. This ensures the uniformity and accuracy of the gap between the inner wall of the mounting bracket and the outer wall of the ceramic sheet, avoiding problems such as mounting bracket misalignment or contact with the ceramic sheet caused by manual assembly errors.

[0013] The present invention will be explained in detail below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 This is a front sectional view of the overall structure of this utility model; Figure 3 This is a schematic diagram of the piezoelectric ceramic sheet, mounting bracket, and assembly strip structure of this utility model; Figure 4 This is a schematic diagram of the internal structure of the outer shell of this utility model; Figure 5 for Figure 2 Enlarged view of point A in the middle.

[0015] The reference numerals in the figure are as follows: 1. Outer shell; 2. Vibrator bearing assembly; 21. Piezoelectric ceramic sheet; 22. Mounting bracket; 23. Coated sheet; 3. Easy assembly assembly; 31. Assembly groove; 32. Assembly strip; 4. Foamed colloid; 5. Conductive lead. Detailed Implementation

[0016] To facilitate understanding of this utility model, a more comprehensive description of the utility model will be given below with reference to the accompanying drawings, which show several embodiments of the utility model. However, the utility model can be implemented in different forms and is not limited to the embodiments described in the text. On the contrary, these embodiments are provided to make the disclosure of the utility model more thorough and comprehensive.

[0017] Example

[0018] Please refer to the appendix carefully. Figure 1-5 An ultrasonic sensor structure for improving detection range includes a housing 1, the inner bottom wall of the housing 1 being a flat surface for mounting a vibrator bearing assembly 2 and an easy-to-assemble assembly 3. The housing 1 is made of metal or engineering plastic, which can ensure structural strength and facilitate injection molding or machining.

[0019] The vibrator support assembly 2 is located on the inner bottom wall of the housing 1. The vibrator support assembly 2 is the core functional unit of the ultrasonic sensor, including a piezoelectric ceramic sheet 21, a mounting bracket 22, and a coating sheet 23. The piezoelectric ceramic sheet 21 is located at the center of the inner bottom wall of the housing 1. The piezoelectric ceramic sheet 21 has a circular structure with upper and lower surfaces. Each surface is provided with a conductive electrode layer. The electrode layer is used to receive external electrical signals or output echo electrical signals. Under the inverse piezoelectric effect, the piezoelectric ceramic sheet 21 can generate radial vibration, thereby converting electrical energy into acoustic energy and radiating ultrasonic waves outward.The mounting bracket 22 is positioned above the piezoelectric ceramic sheet 21 and arranged around its outer periphery. A uniform gap is maintained between the inner wall of the mounting bracket 22 and the outer wall of the piezoelectric ceramic sheet 21, ensuring that the mounting bracket 22 and the piezoelectric ceramic sheet 21 do not contact each other. This avoids rigid constraint on the vibration of the piezoelectric ceramic sheet 21 by the mounting bracket 22, ensuring that the piezoelectric ceramic sheet 21 can vibrate radially in a free state, which is beneficial for the full release of vibration energy. The top of the mounting bracket 22 has a hollow structure, and the opening area of ​​the hollow structure is adapted to the top area of ​​the piezoelectric ceramic sheet 21, allowing the top of the piezoelectric ceramic sheet 21 to be exposed to the light through the hollow area. Above the mounting bracket 22, a coated sheet 23 is embedded in the hollow structure at the top of the mounting bracket 22. The shape of the coated sheet 23 matches the shape of the hollow structure, and the edge of the coated sheet 23 is fixedly connected to the inner wall of the hollow structure, so that the coated sheet 23 is firmly installed at the top of the mounting bracket 22. The bottom of the coated sheet 23 is in contact with the top of the piezoelectric ceramic sheet 21, and the coated sheet 23 covers the entire top surface of the piezoelectric ceramic sheet 21. The coated sheet 23 is a prefabricated independent thin sheet with a uniform structure and consistent thickness, which can effectively ensure the tightness of the fit between the coated sheet 23 and the piezoelectric ceramic sheet 21. The coated sheet 23 is preferably 0.05mm thick. The modified polyurethane elastic film is produced in a single process using a casting molding process. One side of the film undergoes a low-adhesion silicone modification treatment. Its elastic modulus is only 8 MPa, far less than that of the piezoelectric ceramic sheet. When the piezoelectric ceramic sheet vibrates radially, the coated sheet can deform slightly synchronously with the ceramic sheet without generating reverse rigid tension. The mass load effect is less than 3%, and it does not inhibit the maximum amplitude vibration of the ceramic sheet. The ultra-thin thickness of 0.02–0.1 mm minimizes sound wave transmission loss. Simultaneously, the film completely covers the top surface of the piezoelectric ceramic, with the outer perimeter heat-sealed and sealed to the perforated inner wall of the mounting bracket. After the foamed colloid cures, it only contacts the low-adhesion outer surface of the coated sheet and does not penetrate to the surface of the ceramic sheet. The coating layer also functions as an acoustic matching layer within this thickness range, with an acoustic impedance between that of air and piezoelectric ceramic. This significantly reduces the loss of acoustic wave reflection at the interface. The coating layer 23 effectively blocks direct contact between the foamed colloid 4 and the piezoelectric ceramic sheet 21, preventing the foamed colloid 4 from bonding with the piezoelectric ceramic sheet 21 after curing and thus suppressing vibration. This ensures that the piezoelectric ceramic sheet 21 maintains a high vibration amplitude in the working environment after the foamed colloid 4 is filled. It also effectively reduces the reflection of sound waves at the interface between the piezoelectric ceramic sheet 21 and the air, allowing more sound wave energy to enter the air, thereby increasing signal strength, improving detection sensitivity, and improving waveform.

[0020] Both conductive electrode layers of the piezoelectric ceramic sheet 21 are fixedly connected to conductive leads 5. The conductive leads 5 are flexible wires or metal wires used to realize the transmission of electrical signals. One conductive lead 5 is connected to the electrode layer on the upper surface of the piezoelectric ceramic sheet 21, and the other conductive lead 5 is connected to the electrode layer on the lower surface. After both conductive leads 5 are led out from the electrode layer of the piezoelectric ceramic sheet 21, they pass upward through the coating sheet 23 and the foamed colloid 4 filled inside the outer shell 1 in sequence, and finally extend to the outside of the outer shell 1 and form an electrical connection with the external circuit. The conductive leads 5 are made of insulated wires to avoid short circuits.

[0021] The easy-assembly component 3 is disposed on the inner bottom wall surface of the outer shell 1. The easy-assembly component 3 includes an assembly groove 31 and an assembly strip 32. Two assembly grooves 31 are symmetrically opened on both sides of the inner bottom wall surface of the outer shell 1. The assembly groove 31 is an elongated groove extending along the axial direction of the outer shell 1. Its cross-sectional shape can adopt various structural forms such as T-shape, dovetail shape, or rectangle. The assembly groove 31 is used to provide guidance and limit for the assembly strip 32. The assembly strip 32 is assembled inside both assembly grooves 31. The shape of the assembly strip 32 is adapted to the shape of the assembly groove 31. The assembly strip 32 can extend along the edge of the assembly groove 31. The mounting bracket 22 is slidably assembled in the extension direction, thereby realizing the rapid assembly between the mounting bracket 22 and the outer shell 1. The top ends of the two assembly strips 32 are fixedly connected to the two sides of the bottom of the mounting bracket 22 respectively. The assembly strips 32 and the mounting bracket 22 can adopt an integral molding structure or a separate fixed connection structure. Through the sliding cooperation between the assembly groove 31 and the assembly strips 32, the mounting bracket 22 can be accurately positioned at a predetermined position on the inner bottom wall of the outer shell 1, ensuring that the gap between the mounting bracket 22 and the piezoelectric ceramic sheet 21 is uniform and consistent, simplifying the assembly process and improving product consistency and production efficiency.

[0022] The shell 1 is filled with foam 4, which fills all the empty areas inside the shell 1 except for the space occupied by the vibrator support assembly 2. As a sound-absorbing material, the foam 4 can absorb the ultrasonic energy radiated from the back of the piezoelectric ceramic sheet 21, reduce noise interference, and improve the directivity and signal quality of the sensor. The foam 4 encloses the vibrator support assembly 2 inside the shell 1. However, due to the isolation effect of the coating sheet 23 and the gap between the piezoelectric ceramic sheet 21 and the mounting bracket 22, the foam 4 will not come into direct contact with the piezoelectric ceramic sheet 21. The surface of the coating sheet 23 that comes into direct contact with the foam 4 is a low-adhesion surface. The edge of the coating sheet 23 and the fixed connection between the inner wall of the hollow structure of the mounting bracket 22 form a sealing structure to prevent the foam 4 from penetrating. This ensures that the foam 4 will not enter the gap between the inner wall of the mounting bracket 22 and the outer wall of the piezoelectric ceramic sheet 21, thus protecting the free vibration environment of the piezoelectric ceramic sheet 21. After the foamed colloid 4 cures, it forms a stable support structure inside the outer shell 1, further fixing the position of the oscillator bearing assembly 2 and the conductive lead 5. The bottom of the coating sheet 23 is attached to the top of the piezoelectric ceramic sheet 21, but the coating sheet 23 itself is flexible and will not rigidly constrain the vibration of the piezoelectric ceramic sheet 21. At the same time, the elastic modulus of the coating sheet 23 is much lower than that of the piezoelectric ceramic sheet 21, so the mass load effect of the coating sheet 23 on the vibration of the piezoelectric ceramic sheet 21 is minimal. When the piezoelectric ceramic sheet 21 vibrates, the coating sheet 23 deforms slightly synchronously with the piezoelectric ceramic sheet 21 without producing a phase delay, ensuring that the vibration energy of the piezoelectric ceramic sheet 21 is radiated outward to the maximum extent. The edge of the coating sheet 23 is connected to the hollow structure of the mounting bracket 22. The fixed connection on the inner wall is located in the outer area of ​​the top edge of the piezoelectric ceramic sheet 21. The fixed connection does not contact the piezoelectric ceramic sheet 21. The middle area of ​​the coating sheet 23 is attached to the top of the piezoelectric ceramic sheet 21, while the edge area of ​​the coating sheet 23 is fixed to the mounting bracket 22. This connection method of the coating sheet 23 not only ensures the installation stability of the coating sheet 23, but also avoids the mounting bracket 22 from suppressing the vibration of the piezoelectric ceramic sheet 21 through the fixed connection, further ensuring the free vibration conditions of the piezoelectric ceramic sheet 21. At the same time, the covering effect of the coating sheet 23 effectively isolates the foamed colloid 4.

[0023] The specific operation method of this utility model is as follows: When the device is in operation, the external circuit applies an electrical signal to the two conductive electrode layers of the piezoelectric ceramic sheet 21 through the conductive lead 5. Under the inverse piezoelectric effect, the piezoelectric ceramic sheet 21 generates radial vibration and radiates ultrasonic waves outward. Because the mounting bracket 22 is precisely positioned and fixed above the piezoelectric ceramic sheet 21 through the sliding fit of the mounting groove 31 and mounting strip 32 of the easy-assembly component 3 on the inner bottom wall of the outer shell 1, and a gap is left between the outer wall of the piezoelectric ceramic sheet 21 and the inner wall of the mounting bracket 22, the mounting bracket 22 and the piezoelectric ceramic sheet 21 do not contact each other. At the same time, the top of the mounting bracket 22 has a hollow structure with a coating sheet 23 embedded in the hollow area. The edge of the coating sheet 23 is fixedly connected to the inner wall of the hollow structure, while the bottom of the coating sheet 23 is in contact with the top of the piezoelectric ceramic sheet 21. Therefore, during vibration, the top of the piezoelectric ceramic sheet 21 is covered by the coating sheet 23 but is not rigidly constrained by it, and the coating sheet 23... The foam colloid 4 filled inside the outer shell 1 is completely isolated from the piezoelectric ceramic sheet 21, avoiding the damping suppression effect caused by the foam colloid 4 directly adhering to the surface of the piezoelectric ceramic sheet 21. This allows the radial vibration of the piezoelectric ceramic sheet 21 to be fully released and vibrate freely with maximum amplitude, thereby significantly increasing the ultrasonic emission energy and detection distance. When the ultrasonic wave encounters an obstacle and is reflected back to the sensor, the piezoelectric ceramic sheet 21 receives the echo signal and converts it into an electrical signal under the positive piezoelectric effect. The electrical signal is transmitted to the external circuit through the coating sheet 23 and the foam colloid 4 along the conductive lead 5 to realize echo detection. Throughout the process, the oscillator support assembly 2 ensures the free vibration environment of the piezoelectric ceramic sheet 21 in the foam colloid 4 filling state, while the easy assembly assembly 3 ensures the accuracy and consistency of the gap between the mounting bracket 22 and the piezoelectric ceramic sheet 21, ultimately achieving a significant improvement in detection distance.

[0024] The present invention has been described above by way of example in conjunction with the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvement made by adopting the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other occasions without modification, shall be within the protection scope of the present invention.

Claims

1. An ultrasonic sensor structure for improving detection range, comprising a housing (1), characterized in that: The inner bottom wall of the outer shell (1) is provided with a vibrator bearing assembly (2), and the inner bottom wall surface of the outer shell (1) is provided with an easy assembly assembly (3), and the interior of the outer shell (1) is filled with foamed colloid (4).

2. The ultrasonic sensor structure for improving detection distance according to claim 1, characterized in that, The oscillator bearing assembly (2) includes a piezoelectric ceramic sheet (21), a mounting bracket (22), and a coating sheet (23). The piezoelectric ceramic sheet (21) is provided on the bottom wall of the outer shell (1), and the mounting bracket (22) is provided above the piezoelectric ceramic sheet (21). The top of the mounting bracket (22) is provided with a coating sheet (23).

3. The ultrasonic sensor structure for improving detection distance according to claim 2, characterized in that, The outer wall of the piezoelectric ceramic sheet (21) and the inner wall of the mounting bracket (22) are separated by a gap, and the bottom of the coating sheet (23) is attached to the top of the piezoelectric ceramic sheet (21).

4. The ultrasonic sensor structure for improving detection distance according to claim 2, characterized in that, The two conductive electrode layers of the piezoelectric ceramic sheet (21) are fixedly connected with conductive leads (5), and the two conductive leads (5) pass through the coating sheet (23) and the foamed colloid (4) in sequence to connect to the external circuit.

5. The ultrasonic sensor structure for improving detection distance according to claim 1, characterized in that, The easy-assembly component (3) includes an assembly groove (31) and an assembly strip (32). The inner bottom wall surface of the outer shell (1) is provided with an assembly groove (31) on both sides, and an assembly strip (32) is assembled inside the two assembly grooves (31). The top ends of the two assembly strips (32) are fixedly connected to the bottom sides of the mounting bracket (22) respectively.

6. The ultrasonic sensor structure for improving detection distance according to claim 2, characterized in that, The top of the mounting bracket (22) is a hollow structure, and the coating sheet (23) is embedded in the hollow part of the mounting bracket (22), and the edge of the coating sheet (23) is fixedly connected to the inner wall of the hollow structure of the mounting bracket (22).

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