Low frequency band open type ultrasonic wave emitting sensor structure

Abstract

The utility model discloses a kind of low-frequency band open type ultrasonic wave's emission sensor structure, it includes: pedestal, it is composed of bottom shell and inner pedestal;Piezoelectric ceramic piece, it is set on inner pedestal;Pneumatic component, it is combined on the output surface of piezoelectric ceramic piece;And main shell, it is surrounded shell and bottom is combined as a whole in bottom shell, and multiple openings are equipped with in output end side.By the implementation of the new type, the effects of concentrating and focusing sound wave energy, improving acoustic impedance matching, increasing pneumatic component mechanical amplification and improving frequency response can be achieved.

Description

Technical Field

[0001] This utility model belongs to the field of ultrasonic sensing technology, and in particular relates to a low-frequency open ultrasonic transmitting sensor structure. Background Technology

[0002] like Figure 1 As shown, existing ultrasonic sensing devices are frequently used in fields such as distance measurement, motion detection, obstacle avoidance, positioning, or navigation. Their principle is mostly based on the "echo ranging" principle. High-frequency ultrasonic waves are emitted by the ultrasonic transmitter P11, which are transmitted through the air to the object to be measured P20 and reflected. The reflected signal is then received by the ultrasonic receiver P12 to calculate the distance or perform obstacle detection.

[0003] Currently, most commercially available ultrasonic sensors use 40kHz as their standard frequency, and their structural designs are centered around this frequency band for resonance and acoustic adjustments. However, applying the same structure to the 34kHz band, due to the longer wavelength, places different demands on the structure's conical geometry, vibration modes, and acoustic impedance matching, leading to problems such as reduced sound pressure, deteriorated directivity, and frequency mismatch. Furthermore, most sensors lack modular design, requiring completely separate manufacturing processes and models for sensors of different frequency bands, resulting in increased costs.

[0004] It is understood that ultrasonic sensors have the following technical limitations, therefore they cannot be directly applied to the 34kHz frequency band: Frequency matching defects: Commercially available products are designed based on 40kHz, with a wavelength of about 8.5mm. Their piezoelectric sheet thickness is usually about 0.2mm, and the cone size and cone angle are 35°-38°. This does not match the resonance requirement of a wavelength of about 10mm at 34kHz. As a result, when driven at 34kHz, the sound pressure output is reduced by 15-20dB, and the noise peak of the frequency response curve exceeds 5dB.

[0005] Insufficient beam control: The wavelength of low frequency bands is longer, and the cone angle of traditional structures (<40°) cannot constrain the beam diffusion. The sound pressure difference within ±30° range exceeds 10dB, resulting in a misjudgment rate of up to 25% for multi-target interference in short and medium distances.

[0006] Inefficient energy coupling: The acoustic impedance difference between the piezoelectric element and the air is on the order of 10^4. Without a dedicated matching design, the vibration energy reflection loss exceeds 30%. Furthermore, in structures lacking a beryllium bronze coupling layer, resonance stability, such as frequency drift, can reach ±1.2kHz with temperature variations from -10 to 50°C.

[0007] Poor process compatibility: Products in different frequency bands require independent development of models and processes, and the cost of switching between 34kHz and 34kHz production increases by 40%, making modular mass production impossible.

[0008] Most ultrasonic transmitters on the market today are either sealed or partially open. While they can generate ultrasonic signals of a certain frequency, they still fall short in terms of energy concentration and directionality. This is especially true when used for precise ranging or positioning, where signal attenuation and low transmission efficiency are common problems. Furthermore, some devices fail to consider acoustic impedance matching or mechanical coupling characteristics in their material selection, resulting in ineffective conduction of vibrational energy into the air, thus affecting sound pressure output and transmission stability.

[0009] In conclusion, the market urgently needs a high-efficiency, simple-structured, and easily mass-producible open-type ultrasonic transmitter specifically designed for the 34kHz frequency. Its acoustic structure should consider key design parameters such as low-frequency guidance, mechanical resonance stability, acoustic energy conversion efficiency, and packaging transparency. Utility Model Content

[0010] The purpose of this invention is to provide a low-frequency open ultrasonic transmitting sensor structure, which mainly aims to solve the problems of existing ultrasonic transmitters, such as the inability to concentrate sound wave energy, poor acoustic impedance matching, and poor amplitude and frequency response of piezoelectric ceramic sheets.

[0011] This utility model provides a low-frequency open ultrasonic transmitting sensor structure, which includes: a base, which is composed of a bottom shell and an inner base extending from the bottom shell; a piezoelectric ceramic sheet disposed on the inner base; a pneumatic component attached to the output surface of the piezoelectric ceramic sheet; and a main shell, which is a surrounding shell, the bottom of the main shell being integrated with the bottom shell, and the main shell having multiple openings on the output end side.

[0012] As an optional embodiment of this utility model, the bottom shell and the inner base are integrally formed.

[0013] As an optional embodiment of this utility model, the base is a polymer material base or a high-strength bakelite base.

[0014] As an optional embodiment of this utility model, the piezoelectric ceramic sheet is fixed to the inner base with silicone.

[0015] As an optional embodiment of this utility model, the output surface is coupled with a coupling metal sheet.

[0016] As an optional embodiment of this utility model, the pneumatic component is an aluminum cone basin, and the cone portion of the aluminum cone basin is bonded to the center of the coupling metal plate by a fixing adhesive.

[0017] As an optional embodiment of this utility model, the transmitting sensor structure also has a pair of conductive pins, which penetrate the bottom base and are electrically connected to the piezoelectric ceramic sheet.

[0018] As an optional embodiment of this utility model, the main shell is a polymer material main shell, a polyphenylene ether main shell, or an aluminum main shell.

[0019] As an optional embodiment of this utility model, the diameter of the main housing is between 8mm and 10mm.

[0020] As an optional embodiment of this utility model, the ultrasonic frequency output by the pneumatic component is 34kHz to 36kHz.

[0021] This invention has significant advantages and beneficial effects compared with the prior art. Through the above technical solution, the pulp dewatering and drying system of this invention has at least one of the following advantages and beneficial effects: Firstly, frequency matching: There is a clear resonance peak in the range of 33.8-35.5kHz, with a center frequency of 34.2kHz±0.3kHz and a -3dB bandwidth of 2.4kHz, which is 100% higher than the bandwidth (1.2kHz) of a 34kHz sensor of the same size when driven at 34kHz, making it suitable for frequency fluctuation scenarios.

[0022] Secondly, sound energy efficiency: the maximum sound pressure level (SPL) reaches 116dB at a distance of 30cm with 6Vrms drive, which is 3dB higher than the traditional structure (113dB); effectively improving SPL by 41.3%.

[0023] Third, directional control: the sound pressure difference within ±20° is ≤3dB, which is 10dB less than the ±30° difference of the unoptimized 34kHz structure, representing a 70% improvement. The misjudgment rate of multi-target recognition at medium and short ranges is reduced to below 5%.

[0024] Fourth, environmental stability: within a temperature range of -20~60℃, frequency drift ≤±0.3kHz, sound pressure change ≤3dB; in an environment with 95% relative humidity at 40℃, insulation resistance ≥100MΩ, suitable for industrial and outdoor environments.

[0025] Fifth, process compatibility: It shares the base and housing model with 40kHz products, and only the piezoelectric element and aluminum cone need to be replaced, reducing production switching costs by 40% and increasing mass production yield to 98%, compared to about 90% for traditional independent models, which is an improvement of 8%.

[0026] Sixth, it enables the transmitting sensor structure to generate more concentrated and focused acoustic energy.

[0027] Seventh, it can effectively improve the acoustic impedance matching between the transmitting sensor and the air, and enhance the acoustic energy transmission efficiency.

[0028] Eighth, it can increase the mechanical amplification of the pneumatic components of the transmitting sensor structure and improve the frequency response.

[0029] Ninth, it can enhance the high-frequency response of the transmitting sensor structure, especially the part above 34kHz.

[0030] Tenth, this structure is a dedicated 34kHz optimized design. Under the test conditions of a 30cm / 6Vrms driving distance, it has been tested that it can produce a significant resonance response in the range of 33.8~35.5kHz, with a maximum sound pressure level (SPL) of 116dB.

[0031] Eleventh, the pneumatic components adopt a conical structure, which has excellent beam control capabilities and provides stable acoustic energy output within a range of ±20 degrees. Compared with the traditional 40kHz products, which are prone to scattering at low frequencies, this new type is more suitable for short-range sensing.

[0032] Twelfthly, the modular structure allows for the sharing of a 40kHz process platform. Frequency bands can be switched simply by changing the piezoelectric element and cone, enhancing production flexibility and product family expansion capabilities.

[0033] This utility model relates to ultrasonic acoustics and sensor structure design, and in particular to an open-type transmitting sensor with optimized structure and acoustic impedance design for low-frequency (approximately 34kHz) ultrasonic frequencies. It is especially suitable for applications such as precise ranging, motion detection, obstacle recognition, robot navigation, and liquid level sensing over short to medium distances.

[0034] This invention also relates to an ultrasonic acoustic and sensor structure design, specifically optimized for beam control, energy conversion, and resonance stability of 34kHz low-frequency (wavelength approximately 10mm) ultrasound. It is suitable for short-to-medium distance scenarios of 1-5 meters, including precise obstacle avoidance at 1-3 meters for industrial automated guided vehicles (AGVs), human movement detection at 0.5-2 meters for home robots, liquid level sensing at 0.3-1 meters for smart water towers, and navigation and positioning at 2-5 meters for indoor robots. Its core lies in solving the problems of beam diffusion, energy attenuation, and frequency mismatch caused by the characteristics of low-frequency wavelengths, while achieving modular compatibility with 34kHz products.

[0035] In order to enable anyone skilled in the art to understand the technical content of this utility model and implement it accordingly, and based on the content disclosed in this specification, the scope of the patent application and the drawings, anyone skilled in the art can easily understand the related objectives and advantages of this utility model, therefore, the detailed features and advantages of this utility model will be described in detail in the embodiments. Attached Figure Description

[0036] Figure 1 This is a schematic diagram illustrating the application of ultrasonic sensor structures in existing technologies.

[0037] Figure 2This is a three-dimensional exploded view of an embodiment of a low-frequency open ultrasonic transmitting sensor structure according to the present invention.

[0038] Figure 3 This is a three-dimensional combined embodiment of a low-frequency open ultrasonic transmitting sensor structure according to the present invention.

[0039] Figure 4 for Figure 2 Schematic diagram of the embodiment shown in AA cross section.

[0040] Figure 5 This is a diagram showing the frequency response test results of an embodiment of this utility model.

[0041] Explanation of icon numbers P11: Ultrasonic transmitter P12: Ultrasonic receiver P20: Object to be tested 100: Low-frequency open-type ultrasonic transmitter sensor structure 10: Base; 110: Bottom shell 120: Inner base; 20: Piezoelectric ceramic sheet 210: Silicone 220: Coupling metal sheet 30: Pneumatic components; 310: Fixing adhesive 40: Main housing; 50: Conductive pin. 51: Wire Detailed Implementation

[0042] like Figures 2 to 4 As shown, this embodiment is a low-frequency open-type ultrasonic transmitting sensor structure 100, which includes: a base 10; a piezoelectric ceramic sheet 20; a pneumatic component 30; and a main housing 40. This embodiment specifically addresses the low-frequency characteristics of the 34kHz frequency band, overcoming known deficiencies through structural parameter optimization, material matching, and acoustic design. The specific technical solution is as follows: The base 10 consists of a bottom shell 110 and an inner base 120 extending from the bottom shell 110. The bottom shell 110 and the inner base 120 can be integrally formed, which can effectively improve the strength and assembly stability of the overall structure and avoid problems such as displacement or resonance abnormalities caused by splicing multiple structural segments.

[0043] The base 10 can be made of polymer materials, such as high-strength bakelite (phenolic resin PF2A) base. The base 10 has an overall thickness of about 3.2 mm. The base 10 has three radial reinforcing ribs with a width of 1.5 mm and a height of 2 mm inside. By increasing the bending stiffness by 20%, it can also suppress non-target frequencies, such as resonance interference at 28 kHz and 42 kHz.

[0044] Bakelite possesses excellent heat resistance, insulation, and mechanical strength, and its acoustic impedance is 3.5 × 10^6 Pa. The s / m is matched with the piezoelectric ceramic sheet, and the volume resistivity is >10^12Ω. cm ensures insulation and avoids electromagnetic interference between the conductive pin 50 and the piezoelectric ceramic plate 20, making it ideal as a basic support platform for the piezoelectric ceramic plate 20 in an ultrasonic transmitter.

[0045] The bakelite base 10 not only provides stable support for the piezoelectric ceramic sheet 20, but also withstands the mechanical stress generated when the pneumatic component 30 is in operation, and has insulation protection function, which can effectively prevent electrical interference or short circuit between components due to power supply or vibration.

[0046] The piezoelectric ceramic sheet 20 uses a circular piezoelectric component adapted to a 34kHz resonant frequency. The thickness and diameter of the piezoelectric ceramic sheet 20 are designed through calculation to achieve high sound pressure output efficiency. The piezoelectric ceramic sheet 20 has the following parameter design: it uses a circular lead zirconate titanate piezoelectric sheet with a diameter of 8mm ± 0.5mm and a thickness of 0.20mm ± 0.02mm. Through acoustic simulation, such as the piezoelectric equation f = 1 / (2t√(ρc)) (where t is the thickness, ρ is the density, and c is the elastic constant), this size corresponds to a 34kHz resonant frequency, which can ensure a mechanical quality factor Qm > 300 and improve the sound pressure output efficiency by 18%.

[0047] The piezoelectric ceramic sheet 20 is fixed by using silicone 210, which has a Shore hardness of 50±5, to bond to the inner base 120. The thickness of the silicone 210 adhesive layer is 0.15mm±0.03mm. This ensures both the fixing strength, such as shear strength >1.2MPa, and the damping characteristics of silicone 210, such as loss factor tanδ=0.2, which can effectively absorb stray vibrations.

[0048] The piezoelectric ceramic element 20, a type of piezoelectric buzzer, is mounted on the inner base 120. When energized, it generates high-frequency mechanical vibration, thereby producing ultrasonic signals. The piezoelectric ceramic element 20 is fixed to the inner base 120 by silicone 210 to prevent displacement or detachment. Furthermore, the silicone 210, with its good elasticity and adhesion, provides both fixation and vibration damping functions, ensuring a stable output of the required frequency during resonance.

[0049] More specifically, the piezoelectric ceramic sheet 20 in this embodiment mainly generates, for example, 34kHz±1kHz ultrasonic waves and uses them for ultrasonic wave emission. When an alternating voltage of 34kHz±1kHz is applied to the piezoelectric ceramic sheet 20, the piezoelectric ceramic sheet 20 will undergo thickness-direction stretching deformation, that is, the thickness mode of the thickness-direction resonance mode. Such deformation will pull / compress the beryllium bronze sheet, so that the entire piezoelectric ceramic sheet 20 forms a vibrating diaphragm, and through air coupling, a stable 34kHz±1kHz sound wave, that is, a sound pressure wave, is generated.

[0050] Pneumatic component 30 can be a resonant cone, more specifically, an aluminum cone. The cone angle design of the aluminum cone: Based on the sound beam diffusion angle formula θ=2arcsin(λ / (2D)) (λ=10mm, D=7.0mm), the 148° cone angle can confine the sound beam within a range of ±20°. Within this angle, the sound pressure fluctuation is ≤3dB, so as to solve the low frequency diffusion problem.

[0051] The aluminum cone's height design: 0.9mm in height is close to 1 / 16 of the 34kHz wavelength (approximately 0.63mm), which avoids the formation of standing waves inside the cone and reduces the noise peak of the frequency response to less than or equal to 2dB.

[0052] The pneumatic component 30 is integrated onto the output surface of the piezoelectric ceramic plate 20. Its main function is to effectively couple and guide the piezoelectric vibration energy into the air, thereby forming a concentrated and stable ultrasonic beam. The aforementioned cone, especially an aluminum cone (cone) made of aluminum, is preferred. The main functions and applications of the aluminum cone will be described in detail below: 1. Concentrating and focusing sound wave energy (Acoustic Beam Forming / Focusing): As an acoustic guiding structure, the aluminum cone can convert the spherical wave generated by the piezoelectric ceramic sheet 20 into a narrower, more focused directional sound beam, thus improving directivity and effective transmission distance. Therefore, it is particularly suitable for applications that require energy to be concentrated in one direction, such as ranging, focusing, signal transmission, etc.

[0053] 2. Acoustic Impedance Matching: Due to the significant acoustic impedance difference between the piezoelectric ceramic sheet 20 and the air, a large amount of reflection occurs. However, the acoustic impedance of the aluminum cone is between the two, thus it can act as a "matching layer" to improve the radiation efficiency of acoustic energy. Furthermore, the design of the aluminum cone can significantly improve this type of acoustic energy loss, thereby allowing more vibrational energy from the piezoelectric ceramic sheet 20 to be effectively coupled into the air.

[0054] 3. Mechanical Amplification / Vibration Mode Shaping: The aluminum cone is used to change the vibration mode and resonance behavior of the ceramic, for example, to make it present a "piston-like" air-pushing state, thus achieving the most ideal emission state, thereby reducing unnecessary bending or splitting modes, and further increasing the output sound pressure (SPL), and producing a stable resonant frequency, such as at 34kHz.

[0055] 4. Enhanced high-frequency response, especially above 34kHz: The aluminum cone design effectively enhances high-frequency components, resulting in steeper rising / falling edges on the waveform, which is particularly advantageous for applications such as pulsed distance measurement.

[0056] To improve the energy transfer efficiency between the piezoelectric ceramic sheet 20 and the pneumatic component 30, the output surface of the piezoelectric ceramic sheet 20 can be further coupled with a coupling metal sheet 220. The coupling metal sheet 220 is preferably a beryllium bronze metal plate. The surface of the beryllium bronze metal plate can be further electroplated with pure tin to prevent oxidation of the beryllium bronze metal plate and improve weldability.

[0057] Structure and function of coupling metal sheet 220: A 0.2mm±0.01mm beryllium bronze sheet is placed between the piezoelectric ceramic sheet 20 and the aluminum cone basin 30. Its Young's modulus is about 90GPa, which is close to the 70GPa of the piezoelectric ceramic sheet 20. Therefore, it can reduce the reflection of vibration energy and reduce the reflection loss from 25% to 8%.

[0058] In addition, regarding frequency tuning: the mass loading effect of the beryllium bronze sheet can finely tune the resonant frequency, making the impedance modulus |Z|≤50Ω at 34kHz, which matches the drive circuit and improves the power conversion efficiency to 75%, which is a significant improvement of 25% compared to the known structure of about 55%.

[0059] When a coupling metal plate 220 is added between the piezoelectric ceramic plate 20 and the pneumatic component 30, it helps to concentrate and amplify the mechanical energy generated by the vibration of the piezoelectric ceramic plate 20. On the other hand, it can also reduce reflection and loss during the transmission of sound waves, thereby improving the overall efficiency and stability of the transmitter.

[0060] The cone of the cone is fixed to the center of the coupling metal plate 220 by a fixing adhesive 310, such as epoxy resin. Because epoxy resin has good adhesion and mechanical damping effect, it can ensure that the aluminum cone remains stable under high frequency vibration, avoiding loosening or resonance displacement. In addition to improving structural strength, this fixing method also helps the sound wave energy to be stably transmitted from the piezoelectric ceramic to the cone, thereby forming a directional and highly efficient ultrasonic output beam.

[0061] The main housing 40 is a surrounding housing. The bottom of the main housing 40 is integrated with the bottom housing 110 to provide the support and fixation required for the overall structure. In addition, it also serves as a protective housing to cover and protect the aforementioned inner base 120, piezoelectric ceramic sheet 20 and pneumatic component 30.

[0062] Material and structure of main shell 40: The main shell 40 can be a polymer material main shell that is injection molded, especially a polyphenylene ether (PPO) main shell, or the main shell 40 can be an aluminum main shell. The outer diameter of the main shell 40 is 10mm±0.2mm, the length is 7.0mm±0.1mm, and 24 arc holes are opened at the front end, which are arranged in a ring at equal intervals.

[0063] Acoustic advantages of the main housing 40: The acoustic impedance of polyphenylene oxide is 2.8 × 10^6 Pa. s / m, close to 415 Pa in air With a s / m, compared to 3.5×10^6 for conventional acrylonitrile-butadiene-styrene (ABS), it can reduce sound energy reflection by 15%; the 1.2mm aperture is slightly larger than 1 / 8 wavelength (1.25mm) of a 34kHz sound wave, thus reducing diffraction loss by less than 5%.

[0064] The main housing 40 features an anti-interference design: small holes are arranged away from the center of the sound beam, with an offset of approximately 1.5mm, preventing acoustic interference between adjacent holes and ensuring phase consistency within the 33.8-35.5kHz frequency band, with a phase difference ≤5°. The main housing 40 has multiple openings on the output side, arranged in a ring at equal intervals; these openings allow for effective ultrasonic wave penetration and emission, preventing sound wave energy attenuation or interference. The main housing 40 is preferably made of polyphenylene oxide (PPO) polymer material, giving it excellent rigidity, heat resistance, and electrical insulation. The diameter of the main housing 40 is between 8mm and 10mm, making it suitable for miniaturization and modular design requirements.

[0065] The above embodiment may further include a pair of conductive pins 50, the structure and performance of which are as follows: made of phosphor bronze #C5191, with a diameter of 0.7mm±0.05mm, pre-embedded in the base 10 by injection molding, with an embedding depth of 5mm, an exposed length of 3mm, and an insulation gap of 0.5mm±0.1mm between the pins and the base 10, which can prevent leakage current greater than 1μA (>1μA).

[0066] Electrical connection: The conductive pin 50 is soldered to the piezoelectric ceramic sheet 20 and the coupling metal sheet / beryllium bronze sheet 220 through the enameled wire 51 with a diameter of 0.1mm. The solder joint is 1.5mm away from the edge of the piezoelectric ceramic sheet 20. By avoiding vibration nodes, the contact resistance is ensured to be stable under 1kHz vibration, that is, less than 50mΩ (<50mΩ).

[0067] The conductive pin 50 can be embedded in the base 10 by injection molding during the manufacturing of the base 10, so that the conductive pin 50 penetrates the base 10, and then the conductive pin 50 is electrically connected to the silver electrodes printed on the upper and lower sides of the piezoelectric ceramic sheet 20 through the wire 51.

[0068] The conductive pin 50 can be used to transmit the driving voltage generated by the external driving circuit to the piezoelectric ceramic plate 20 to trigger the piezoelectric ceramic plate 20 to generate vibration and sound wave output. The driving voltage / distance conditions are: 30cm 6Vrms, and the maximum effective sound pressure level is 116dB (SPLMax116dBSPL).

[0069] Assembly process in this embodiment: Step 1: Injection molding of base 10 / bakelite base, pre-embed conductive pins 50, ensuring pin verticality ≤0.1mm / m; Step 2: The piezoelectric ceramic sheet 20 and the coupling metal sheet / beryllium bronze sheet 220 are bonded together with adhesive 310 / epoxy resin. The adhesive layer of adhesive 310 / epoxy resin is about 0.05mm thick. After curing, the resonant frequency is tested to be about 34.2±0.3kHz. Step 3: Fix the assembly to the inner base 120 with silicone 210, and cure the adhesive layer at 25°C for 24 hours; Step 4: The pneumatic component / aluminum cone 30 is bonded to the center of the coupling metal plate / beryllium bronze plate with adhesive 310 / epoxy resin, and the coaxiality is ≤0.1mm; Step 5: The main housing 40 and the bottom housing 110 are glued together to ensure mechanical strength.

[0070] like Figure 5 As shown, the test verification in this embodiment is as follows: Anisotropic chamber test: 6Vrms sine wave drive, at a distance of 30cm, SPL=116dB at 34kHz. Harmonic distortion ≤3%; Directivity test: Take points every 5° on the rotating platform, plot polar coordinates, and confirm that the sound pressure level is ≥113dB within ±20°; Reliability test: After 10^6 vibrations driven at 34kHz and 1.5Vrms, the structure showed no cracks and the electrical performance degradation was ≤2%.

[0071] This embodiment is particularly suitable for applications in the 34kHz to 36kHz frequency range. Frequency response test results show a significant resonance peak in the 34kHz to 36kHz range, with a maximum sound pressure level (SPL) of 116dB, demonstrating excellent energy concentration and frequency stability. Compared to similar products, this embodiment exhibits stronger directivity and effective emission intensity in the mid-to-high frequency band, making it particularly suitable for high-resolution distance measurement, obstacle detection, and high-frequency positioning applications. It also confirms a significant improvement in acoustic efficiency.

[0072] This invention addresses the performance deficiencies of traditional 34kHz structures applied to low-frequency bands through optimized structural parameters, material matching, and acoustic design specific to the 34kHz frequency band. It exhibits significant technical advantages in sound pressure output, directivity control, and environmental stability, while also being compatible with mass production. It is suitable for short-to-medium distance, high-precision sensing scenarios and possesses strong patent protection value and market competitiveness.

[0073] The above embodiments are used to illustrate the features of this utility model. Their purpose is to enable those skilled in the art to understand the content of this utility model and implement it accordingly, rather than to limit the patent scope of this utility model. Therefore, any equivalent modifications or alterations made without departing from the spirit disclosed in this utility model should still be included in the following patent scope of this application.

Claims

1. A low frequency band open type ultrasonic wave transmitting sensor structure, characterized by, include: The base consists of a bottom shell and an inner base extending from the bottom shell; A piezoelectric ceramic sheet is disposed on the inner base; A pneumatic component, which is attached to the output surface of the piezoelectric ceramic sheet; as well as The main housing is a surrounding housing, and its bottom is integrated with the bottom housing. The main housing has multiple openings on the output side.

2. The transmitting sensor structure of claim 1, wherein, The bottom shell and the inner base are integrally formed.

3. The transmitting sensor structure of claim 1, wherein, The base can be a polymer material base or a high-strength bakelite base.

4. The launch sensor structure of claim 1, wherein, The piezoelectric ceramic sheet is fixed to the inner base with silicone.

5. The launch sensor structure of claim 1, wherein, The output surface is coupled with a coupling metal sheet.

6. The transmitting sensor structure of claim 5, wherein, The pneumatic component is an aluminum cone basin, and the cone of the aluminum cone basin is bonded to the center of the coupling metal plate by a fixing adhesive.

7. The launch sensor structure of claim 1, wherein, The transmitting sensor structure also has a pair of conductive pins that penetrate the bottom base and are electrically connected to the piezoelectric ceramic sheet.

8. The launch sensor structure of claim 1, wherein, The main shell is made of polymer material, polyphenylene ether, or aluminum.

9. The launch sensor structure of claim 1, wherein, The diameter of the main housing is between 8mm and 10mm.

10. The launch sensor structure of claim 1, wherein, The ultrasonic frequency output by this pneumatic component is 34kHz to 36kHz.

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