Acoustic emission sensor and track crack detection device
By introducing radial vibration holes and metal mass into the acoustic emission sensor, the problem that existing sensors cannot detect large cross-section cracks is solved, and the response to the 60kHz frequency is achieved, which improves detection accuracy and reduces costs.
Patent Information
- Application Number
- CN202422242116.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-12
- Publication Date
- 2025-07-08
- Estimated Expiration
- 2034-09-12
AI Technical Summary
The acoustic emission sensors used on existing high-speed railways cannot effectively detect cracks with large cross-sections. Sensors with a center frequency of 140kHz are not suitable when the crack section is greater than 50%.
A sound emission sensor is designed, using the radial vibration detection mode of the radial vibration hole, combining the connection of the metal mass and the conductive adhesive layer, and the transmission line is connected to the metal mass, achieving a 60kHz frequency response and adapting to crack detection with larger cross-sections.
Without changing the sensor size, the response sensitivity to acoustic waves of a specific frequency and the accuracy of crack detection are improved, the cost is reduced, and the field fixture can be used for universal field fixtures.
Smart Images
Figure CN223078254U_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of acoustic emission sensors, and in particular to an acoustic emission sensor and a track crack detection device. Background Art
[0002] Acoustic emission sensors are the sensing elements of the acoustic emission detection system. They are mainly used to detect the initiation and expansion of cracks at railway switches on high-speed railways, and play a very important role in the safe operation of high-speed railways.
[0003] Among the existing technologies, the acoustic emission sensors commonly used on high-speed railways have a center frequency of about 140kHz, which is a receiving type. It receives the vibration signal generated by the train passing, causes the piezoelectric ceramic to produce a piezoelectric effect, outputs a trace charge signal, and detects slight cracks on the rails by observing the change in the signal, but it cannot determine the exact location of the crack, and the maximum transmission distance is about 10 meters. When the crack section is greater than 50%, the sensor with a center frequency of 140kHz is not applicable. Therefore, it is necessary to design an acoustic emission sensor with a center frequency of about 60kHz to detect cracks with larger sections. Summary of the invention
[0004] In view of the deficiencies in the prior art, the purpose of the present invention is to provide an acoustic emission sensor and a track crack detection device, aiming to solve the technical problem in the prior art that cracks with larger cross-sections cannot be detected.
[0005] In order to achieve the above-mentioned purpose, the present invention is implemented through the following technical scheme: an acoustic emission sensor, comprising a sensor body, an alumina ceramic sheet fixed to one side of a signal receiving surface of the sensor body, and a piezoelectric ceramic arranged on one side of the alumina ceramic sheet, a metal mass block is provided on one side of the piezoelectric ceramic, a first conductive adhesive layer is provided between the alumina ceramic sheet and the piezoelectric ceramic, a second conductive adhesive layer is provided between the piezoelectric ceramic and the metal mass block, a first radial vibration hole is opened in the middle of the piezoelectric ceramic, a second radial vibration hole is opened in the middle of the metal mass block, and the acoustic emission sensor also includes a signal transmission connector, and a transmission line is provided between the signal transmission connector and the metal mass block.
[0006] Compared with the prior art, the beneficial effects of the present invention are as follows: Compared with the detection mode of conventional telescopic vibration, in order to adapt to the frequency response of 60 kHz, the size of the piezoelectric ceramic needs to be increased, and the original shell size and the fixtures matching the track need to be redesigned. In this solution, on the basis of the original ceramic chip, the detection mode of the original telescopic vibration of the piezoelectric ceramic is designed into a radial vibration detection mode with radial vibration holes. Without changing the external dimensions of the sensor, a frequency response of 60 kHz is achieved, so that the fixtures at the sensor installation site can be made universal, reducing costs. By arranging a metal mass block for damping on the piezoelectric ceramic and correspondingly arranging radial vibration holes, and connecting the metal mass block through a conductive adhesive layer, and connecting the transmission line to the metal mass block to form an acoustic emission sensor, the detection of track cracks with a larger cross-section is realized.
[0007] According to one aspect of the above technical solution, an assembly groove corresponding to the piezoelectric ceramic is provided on one side of the metal mass block close to the piezoelectric ceramic.
[0008] According to one aspect of the above technical solution, the first radial vibration hole and the second radial vibration hole are coaxially arranged.
[0009] According to one aspect of the above technical solution, the transmission line includes a copper wire electrically connected to the metal mass block and a heat-melt tube for coating the copper wire.
[0010] According to one aspect of the above technical solution, a fixed joint corresponding to the heat-melt tube is provided on one side of the sensor body, and an insulating sleeve is provided between the fixed joint and the heat-melt tube.
[0011] According to one aspect of the above technical solution, the sensor body includes a body part, a housing part provided outside the body part, and a fixing member for connecting the body part and the housing part.
[0012] According to one aspect of the above technical solution, the transmission line further includes a shield wire connected to the body part.
[0013] According to one aspect of the above technical solution, a pressure wire tube for fixing the heat-melt tube is further provided on one side of the signal transmission joint, and a ferrule for fixing the copper wire is provided on the side of the signal transmission joint away from the pressure wire tube.
[0014] According to one aspect of the above technical solution, the acoustic emission sensor further includes a first protective cover detachably provided on the ferrule and a second protective cover provided on one side of the sensor body, and the second protective cover is provided on the side of the sensor body close to the alumina ceramic chip.
[0015] On the other hand, the present application also provides an orbital crack detection device, which includes the acoustic emission sensor in the above technical solution. The orbital crack detection device further includes a charge amplifier connected to the acoustic emission sensor, and a signal detection device connected to one end of the charge amplifier. Description of the Drawings
[0016] Figure 1 It is a partial cross-sectional structural schematic diagram of the acoustic emission sensor in the first embodiment of the present invention;
[0017] Figure 2 is Figure 1 the enlarged view of part A in
[0018] Figure 3 is Figure 1 the enlarged view of part B in
[0019] Main element symbol description:
[0020] Sensor body 10, housing part 11, body part 12, fixing part 13, alumina ceramic sheet 21, piezoelectric ceramic 22, first radial vibration hole 22a, metal mass block 23, second radial vibration hole 23a, heat fusion tube 31, copper wire 32, shielded wire 33, insulating sleeve 41, fixed joint 42, signal transmission joint 51, pressure pipe 52, ferrule sleeve 53, second protective sleeve 61, first protective sleeve 62;
[0021] The following specific embodiments will further illustrate the present invention in conjunction with the above drawings. Specific Embodiments
[0022] For the convenience of understanding the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. Several embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.
[0023] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there can also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.
[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this invention belongs. The terms used in the specification of this invention are for the purpose of describing specific embodiments only and are not intended to limit the invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.
[0025] Please refer to Figures 1 to 3 , which shows the acoustic emission sensor in the first embodiment of the present invention, including a sensor body 10, an alumina ceramic sheet 21 fixed on one side of the signal receiving surface of the sensor body 10, and a piezoelectric ceramic 22 provided on one side of the alumina ceramic sheet 21. A metal mass block 23 is provided on one side of the piezoelectric ceramic 22. A first conductive adhesive layer is provided between the alumina ceramic sheet 21 and the piezoelectric ceramic 22, and a second conductive adhesive layer is provided between the piezoelectric ceramic 22 and the metal mass block 23. A first radial vibration hole 22a is formed in the middle of the piezoelectric ceramic 22, and a second radial vibration hole 23a is formed in the middle of the metal mass block 23. The acoustic emission sensor further includes a signal transmission connector 51, and a transmission line is provided between the signal transmission connector 51 and the metal mass block 23.
[0026] In some application scenarios of this embodiment, when the sensor is installed at a railway turnout, the vibration sound wave generated when the train passes is transmitted into the piezoelectric ceramic 22 through the alumina ceramic sheet 21. The piezoelectric ceramic 22 generates radial vibration under the action of the sound wave and converts the vibration into an electrical signal through the piezoelectric effect. The design of the metal mass block 23 not only increases the mass of the sensor but also couples with the vibration mode of the piezoelectric ceramic 22 through the radial vibration holes thereon, enhancing the response of the sensor to sound waves of a specific frequency (60 kHz). Through the design of the metal mass block 23 and the radial vibration holes, the response sensitivity of the sensor to sound waves of a specific frequency is improved, thereby improving the accuracy of crack detection. Finally, the electrical signal is transmitted to an external processing device through the transmission line for analysis to determine the presence and location of cracks.
[0027] Specifically, in this embodiment, the above-mentioned piezoelectric ceramic 22 is a cylinder with a height of 13 mm - 15 mm and a diameter of 24 mm - 26 mm; the diameter of the first radial vibration hole 22a is 9 mm - 11 mm. Preferably, in this embodiment, the piezoelectric ceramic 22 has a height of 14.2 mm, a diameter of 25.6 mm, and the diameter of the first radial vibration hole 22a is 10 mm. The above-mentioned metal mass block 23 is a cylinder with a height of 6 mm - 8 mm and a diameter of 25 mm - 27 mm; the diameter of the second radial vibration hole 23a is 8 mm - 10 mm. Preferably, in this embodiment, the metal mass block 23 has a height of 7.16 mm, a diameter of 26.76 mm, and the diameter of the second radial vibration hole 23a is 9.28 mm.
[0028] For better understanding, compared with the detection mode of conventional telescopic vibration, in order to adapt to the frequency response of 60 kHz, the size of the piezoelectric ceramic 22 needs to be increased, and the original shell size and the fixtures matching on the track need to be redesigned. In this solution, on the basis of the original ceramic chip, the detection mode of the original telescopic vibration of the piezoelectric ceramic is designed into a radial vibration detection mode with radial vibration holes. Without changing the external dimensions of the sensor, a frequency response of 60 kHz is achieved, so that the fixtures at the sensor installation site can be made universal, reducing costs. By arranging a metal mass block 23 for damping on the piezoelectric ceramic 22 and correspondingly arranging radial vibration holes, and connecting the metal mass block 23 through a conductive adhesive layer, and connecting a transmission line to the metal mass block 23 to form an acoustic emission sensor, the detection of track cracks with a larger cross-section is realized.
[0029] Specifically, in this embodiment, on one side of the metal mass block 23 close to the piezoelectric ceramic 22, an assembly groove corresponding to the piezoelectric ceramic 22 is provided, and the first radial vibration hole 22a and the second radial vibration hole 23a are coaxially arranged. By providing the above-mentioned assembly groove, an accurate positioning point is provided for the piezoelectric ceramic 22, so that the piezoelectric ceramic 22 can be accurately aligned with the metal mass block 23 during installation, avoiding performance degradation caused by position deviation. The tight fit between the assembly groove and the piezoelectric ceramic 22, combined with the use of the second conductive adhesive layer, further enhances the connection strength and stability between the piezoelectric ceramic 22 and the metal mass block 23, helps to reduce energy loss during vibration transmission, and improves the overall performance of the sensor.
[0030] Furthermore, in this embodiment, the above-mentioned transmission line includes a copper wire 32 electrically connected to the metal mass block 23 and a heat-melt tube 31 for covering the copper wire 32.
[0031] Specifically, in this embodiment, on one side of the sensor body 10, a fixed joint 42 corresponding to the heat-melt tube 31 is provided, and an insulating sleeve 41 is provided between the fixed joint 42 and the heat-melt tube 31. The main function of the fixed joint 42 is to firmly fix the heat-melt tube 31 (and the copper wire 32 inside it) on the sensor body 10, ensuring the continuity and stability of signal transmission, preventing the heat-melt tube 31 from loosening or falling off under the action of external factors such as vibration and impact, thus ensuring the reliability of signal transmission. The insulating sleeve 41 is located between the fixed joint 42 and the heat-melt tube 31, mainly playing the role of insulation and isolation, preventing short circuits or leakage between the fixed joint 42 and the heat-melt tube 31 (and the copper wire 32 inside it), thus ensuring the safety of signal transmission.
[0032] Furthermore, in the present embodiment, the above-mentioned sensor body 10 includes a body portion 12, a housing portion 11 provided outside the body portion 12, and a fixing member 13 for connecting the body portion 12 and the housing portion 11. The transmission line further includes a shielded wire 33 connected to the body portion 12. The shielded wire 33 is a part of the transmission line and is connected to the body portion 12. It is mainly used to reduce the influence of external electromagnetic interference on signal transmission and improve the stability and accuracy of the signal. Through the design of the shielding layer, the surrounding electromagnetic noise and interference signals can be effectively shielded to ensure the quality of the transmitted signal. The above-mentioned fixing member 13 is preferably a screw.
[0033] Specifically, in the present embodiment, a pressure line tube 52 for fixing the hot melt tube 31 is further provided on one side of the above-mentioned signal transmission joint 51, and a ferrule 53 for fixing the copper wire 32 is provided on the side of the signal transmission joint 51 away from the pressure line tube 52. The ferrule 53 is located on the side of the signal transmission joint 51 away from the pressure line tube 52, and its main function is to fix the copper wire 32.
[0034] Preferably, in the present embodiment, the above-mentioned acoustic emission sensor further includes a first protective cover 62 detachably provided on the ferrule 53, and a second protective cover 61 provided on one side of the sensor body 10. The second protective cover 61 is provided on the side of the sensor body 10 close to the alumina ceramic chip 21.
[0035] In summary, for the acoustic emission sensor in the above-mentioned embodiment of the present invention, compared with the conventional detection mode of telescopic vibration, in order to adapt to the frequency response of 60 kHz, the size of the piezoelectric ceramic 22 needs to be increased, and the original outer shell size and the fixture matching on the track need to be redesigned. In this solution, on the basis of the original ceramic chip, the original detection mode of telescopic vibration of the piezoelectric ceramic is designed into a radial vibration detection mode with radial vibration holes. Without changing the external dimensions of the sensor, a frequency response of 60 kHz is achieved. In this way, the fixture at the sensor installation site can be made universal, and the cost can be reduced. By providing a metal mass block 23 for damping on the piezoelectric ceramic 22 and correspondingly providing radial vibration holes, and connecting the metal mass block 23 through a conductive adhesive layer, and connecting the transmission line to the metal mass block 23 to form an acoustic emission sensor, the detection of track cracks with a relatively large cross-section is realized.
[0036] The second embodiment of the present application provides a track crack detection device, including the acoustic emission sensor in the above-mentioned embodiment. The above-mentioned track crack detection device further includes a charge amplifier connected to the acoustic emission sensor, and a signal detection device connected to one end of the charge amplifier.
[0037] By setting up a charge amplifier to amplify the signal, it is possible to effectively amplify the weak charge signal output by the acoustic emission sensor, enhance the signal intensity, reduce the attenuation of the signal during transmission in the cable, thereby greatly improving the signal transmission distance and transmission quality, and ensuring the accuracy and integrity of the signal.
[0038] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.
[0039] The above-described embodiments merely represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the appended claims.
Claims
1. An acoustic emission sensor, characterized in that, It includes a sensor body, an alumina ceramic sheet fixed on one side of the signal receiving surface of the sensor body, and a piezoelectric ceramic provided on one side of the alumina ceramic sheet. A metal mass block is provided on one side of the piezoelectric ceramic. A first conductive adhesive layer is provided between the alumina ceramic sheet and the piezoelectric ceramic, and a second conductive adhesive layer is provided between the piezoelectric ceramic and the metal mass block. A first radial vibration hole is formed in the middle of the piezoelectric ceramic, and a second radial vibration hole is formed in the middle of the metal mass block. The acoustic emission sensor further includes a signal transmission connector, and a transmission line is provided between the signal transmission connector and the metal mass block.
2. The acoustic emission sensor according to claim 1, characterized in that, An assembly groove corresponding to the piezoelectric ceramic is provided on the side of the metal mass block close to the piezoelectric ceramic.
3. The acoustic emission sensor according to claim 1, characterized in that, The first radial vibration hole and the second radial vibration hole are coaxially arranged.
4. The acoustic emission sensor according to claim 1, characterized in that, The transmission line includes a copper wire electrically connected to the metal mass block and a heat fusion tube for coating the copper wire.
5. The acoustic emission sensor according to claim 4, wherein A fixed connector corresponding to the heat fusion tube is provided on one side of the sensor body, and an insulating sleeve is provided between the fixed connector and the heat fusion tube.
6. The acoustic emission sensor according to claim 1, wherein The sensor body includes a body part, a housing part provided on the outside of the body part, and a fixing member for connecting the body part and the housing part.
7. The acoustic emission sensor according to claim 6, characterized in that The transmission line further includes a shield wire connected to the body part.
8. The acoustic emission sensor according to claim 4, characterized in that, A pressure line tube for fixing the heat fusion tube is further provided on one side of the signal transmission connector, and a ferrule for fixing the copper wire is provided on the side of the signal transmission connector away from the pressure line tube.
9. The acoustic emission sensor according to claim 8, wherein The acoustic emission sensor further includes a first protective sleeve detachably provided on the ferrule and a second protective sleeve provided on one side of the sensor body. The second protective sleeve is provided on the side of the sensor body close to the alumina ceramic sheet.
10. An orbital crack detection device, characterized in that, Including the acoustic emission sensor according to any one of claims 1-9, the track crack detection device further includes a charge amplifier connected to the acoustic emission sensor and a signal detection device connected to one end of the charge amplifier.