Acceleration sensor with dual detection body

Abstract

The utility model provides an acceleration sensor with double detection bodies, and belongs to the technical field of acceleration sensors, the acceleration sensor comprises a first sensor, a second sensor and an integration bin, the first sensor and the second sensor are capacitive acceleration sensors, and the resonant frequency of the first sensor is higher than that of the second sensor; the first sensor and the second sensor are fixedly installed in the first fixing cavity and the second fixing cavity of the integration bin respectively. The first sensor and the second sensor are integrated through the integration bin to measure the acceleration of a measured object. Compared with the sensor II, the sensor I has a relatively high measurement range but relatively low sensitivity. When a mechanical product with complex vibration frequency is measured, the high-sensitivity measurement of the second sensor is used as a measurement result in the common measurable frequency range of the first sensor and the second sensor, and the measurement of the first sensor is used as a measurement result in the measurable frequency range higher than the measurable frequency range of the second sensor, so that the measurement range and the sensitivity are both considered.

Description

Technical Field

[0001] This utility model belongs to the field of acceleration sensor technology, and more specifically, relates to an acceleration sensor with dual detection subjects. Background Technology

[0002] A capacitive accelerometer is a sensor that converts the measured acceleration signal into a change in the capacitance of a capacitor. It comprises a sandwich structure consisting of an upper electrode, a lower electrode, and a movable intermediate electrode. For example, the MEMS accelerometer seismic sensor disclosed in the applicant's patent application with publication number CN100458466C. The intermediate electrode is connected to a mass block via a cantilever beam. When acceleration occurs, the mass block displaces relative to the upper and lower electrodes, causing a change in the capacitance and thus detecting the acceleration.

[0003] Resonant frequency and sensitivity are important parameters affecting the measurements of capacitive accelerometers. A higher resonant frequency generally corresponds to a higher upper limit of the sensor's usable frequency range. The resonant frequency of an accelerometer... The relationship between the equivalent stiffness and the equivalent mass M is as follows:

[0004]

[0005] This shows that increasing the resonant frequency of a sensor requires either increasing the stiffness of the cantilever beam or reducing the mass of the mass block. This leads to a decrease in the displacement of the mass block under the same acceleration, resulting in a decrease in capacitance change and consequently a decrease in sensor sensitivity. In other words, high-frequency capacitive sensors have low sensitivity, while low-frequency capacitive sensors have high sensitivity; high sensitivity and high resonant frequency are mutually exclusive and cannot be simultaneously achieved. Furthermore, in complex vibration scenarios, using only a high-sensitivity capacitive accelerometer can easily lead to distortion of some detection data due to frequencies exceeding the required range. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides an accelerometer with dual detection bodies, integrating a high-frequency capacitive sensor and a low-frequency capacitive sensor to compensate for the incompatibility between sensitivity and frequency range, making it suitable for detection situations with complex vibration frequencies.

[0007] To achieve the above objectives, the technical solution of this application provides an accelerometer with dual detection bodies, including sensor one, sensor two, and an integrated chamber. Sensor one and sensor two are both capacitive accelerometers, and the resonant frequency of sensor one is higher than that of sensor two. The integrated chamber has a fixed cavity one and a fixed cavity two. Sensor one is fixedly installed in fixed cavity one, and sensor two is fixedly installed in fixed cavity two. The outer wall of the integrated chamber is provided with terminal one and terminal two. Terminal one is connected to sensor one, and terminal two is connected to sensor two.

[0008] The integrated unit combines Sensor 1 and Sensor 2 to measure the acceleration of the object under test. Compared to Sensor 2, Sensor 1 has a wider measurement range but relatively lower sensitivity. When detecting vibration frequencies with complex characteristics, within the common measurable frequency range, the measurement result is obtained using the high sensitivity of Sensor 2. Beyond the measurable frequency range of Sensor 2, the measurement result is obtained using the measurement of Sensor 1. This achieves both high sensitivity within a specific range and a wider frequency measurement range.

[0009] Optionally, sensor one and sensor two have upper and lower electrodes of the same specifications. Sensor one also includes an intermediate electrode one, and sensor two also includes an intermediate electrode two. Intermediate electrodes one and two have frames and cantilever beams of the same specifications. Both intermediate electrodes one and two also have mass blocks, which are installed in their respective frames via corresponding cantilever beams. The number and arrangement of cantilever beams in intermediate electrode one are the same as those in intermediate electrode two, and the mass of the mass block in intermediate electrode one is less than that in intermediate electrode two. In this way, the resonant frequency of sensor one is higher than that of sensor two only by the difference in the mass of the mass blocks, while the specifications of all other components are exactly the same, facilitating production integration.

[0010] Optionally, the mass block in intermediate electrode one has a vertically penetrating vent hole one at its center, and the mass block in intermediate electrode two has a vertically penetrating vent hole two at its center. The mass blocks in intermediate electrode one and intermediate electrode two have the same outer circumferential dimensions, but the size of vent hole one is larger than the size of vent hole two. The difference in the size of vent hole one and vent hole two achieves the difference in mass of the mass blocks in intermediate electrode one and intermediate electrode two. Since the mass blocks in intermediate electrode one and intermediate electrode two have the same outer circumferential dimensions, it ensures that they can be connected to mass blocks of different masses in the same way through the same frame and cantilever beam. This means that the only difference between sensor one and sensor two is the size of vent hole one and vent hole two, which facilitates production. At the same time, the arrangement of vent hole one and vent hole two also allows air to easily circulate between the top and bottom of the mass block, reducing the restriction on the movement of the mass block caused by air resistance and improving measurement accuracy.

[0011] Optionally, sensor one and sensor two have upper and lower electrodes of the same specifications. Sensor one also includes an intermediate electrode one, and sensor two also includes an intermediate electrode two. Intermediate electrodes one and two have frames, mass blocks, and cantilever beams of the same specifications. The mass blocks are mounted in the corresponding frames via corresponding cantilever beams. The number of cantilever beams in intermediate electrode one is greater than the number of cantilever beams in intermediate electrode two. In this way, the resonant frequency of sensor one is higher than that of sensor two only by the difference in the number of cantilever beams, while the specifications of all other components are exactly the same, which facilitates production integration.

[0012] Optionally, it also includes vibration damping components. The integrated chamber includes chamber body one and chamber body two. Fixed cavity one is located in chamber body one, and fixed cavity two is located in chamber body two. Terminal one is located on the outer wall of chamber body one, and terminal two is located on the outer wall of the fixed cavity. Sensor one is embedded in fixed cavity one through an interference fit, and sensor two is embedded in fixed cavity two through an interference fit. Chamber body one is fixedly connected to chamber body two through vibration damping components. Since sensor one and sensor two contain a large number of components with the same specifications, and because the interference fit easily transmits vibration, component resonance is likely to occur in complex vibration environments, causing measurement distortion. By isolating chamber body one and chamber body two through vibration damping components, the vibration of the measured object is transmitted to sensor one through chamber body one, and the vibration of the measured object is transmitted to sensor two through chamber body two. The vibration transmission between chamber body one and chamber body two is relatively small, which reduces the mutual influence of vibration between sensor one and sensor two and reduces resonance.

[0013] Optionally, the bottom walls of both chamber 1 and chamber 2 are bonding walls designed to fit against the object being measured. With the bonding walls attached to the object, vibrations can be better transmitted to sensor 1 and sensor 2 through these walls.

[0014] Optionally, the fitting walls of compartment one and compartment two are flush, so that compartment one and compartment two can fit together on a flat surface at the same time, which is suitable for objects with flat surfaces.

[0015] Optionally, the fitting walls of chamber one and chamber two are arranged at different heights to accommodate objects with stepped surfaces.

[0016] Optionally, both fixed chamber one and fixed chamber two have top openings. The frame of both intermediate electrode one and intermediate electrode two are provided with exhaust channels one and two. Exhaust channel one communicates with the top side of the corresponding mass block, and exhaust channel two communicates with the bottom side of the corresponding mass block. The inner walls of both fixed chamber one and fixed chamber two have flow channels connecting to the corresponding exhaust channels one and two. When the mass block vibrates up and down, the gas at the top and bottom of the mass block communicates with the outside through the exhaust channels and flow channels, achieving pressure balance between the top and bottom of the mass block, reducing the restriction on mass block movement caused by air resistance, and improving measurement sensitivity.

[0017] The advantages of the technical solution in this application compared to the prior art are as follows:

[0018] The integrated unit combines Sensor 1 and Sensor 2 into a single unit to measure the acceleration of the object under test. Compared to Sensor 2, Sensor 1 has a wider measurement range but relatively lower sensitivity. Therefore, when measuring mechanical products with complex vibration frequencies, within the common measurable frequency range, the high-sensitivity measurement of Sensor 2 is used as the measurement result, while in frequencies exceeding the measurable frequency range of Sensor 2, the measurement of Sensor 1 is used as the result. This achieves both high-sensitivity measurement requirements within a specific range and a wider frequency measurement range. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 A schematic diagram of the overall structure of an accelerometer with dual detection bodies;

[0021] Figure 2 This is an exploded view of the first type of accelerometer with dual detection bodies.

[0022] Figure 3 for Figure 2 Schematic diagram of intermediate electrode one and intermediate electrode two;

[0023] Figure 4 A schematic diagram of the bottom structure of an accelerometer with dual detection bodies;

[0024] Figure 5 A schematic diagram of an accelerometer structure with dual detection bodies arranged in a staggered manner to fit against the wall;

[0025] Figure 6 This is a schematic diagram of the connection structure of the circulation channel;

[0026] Figure 7 An exploded view of the second type of accelerometer structure with dual detection bodies;

[0027] Figure 8 for Figure 7 Schematic diagram of intermediate electrode one and intermediate electrode two.

[0028] Icons: 1. Sensor 1; 2. Sensor 2; 3. Integrated chamber; 4. Fixed cavity 1; 5. Fixed cavity 2; 6. Terminal 1; 7. Terminal 2; 8. Upper electrode; 9. Lower electrode; 10. Middle electrode 1; 11. Middle electrode 2; 12. Frame; 13. Mass block; 14. Cantilever beam; 15. Air vent 1; 16. Air vent 2; 17. Shock absorber; 18. Chamber 1; 19. Chamber 2; 20. Fitting wall; 21. Exhaust channel 1; 22. Exhaust channel 2; 23. Flow channel. Detailed Implementation

[0029] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0030] Example 1:

[0031] This embodiment provides an accelerometer with dual detection subjects, based on Figure 1 and Figure 2 As shown, the system includes sensor 1, sensor 2, and an integrated chamber 3. Sensors 1 and 2 are both capacitive accelerometers with identical structures. The resonant frequency of sensor 1 is higher than that of sensor 2, thus the applicable frequency measurement range of sensor 1 is wider than that of sensor 2, and the sensitivity of sensor 1 is lower than that of sensor 2. The integrated chamber 3 has a fixed cavity 4 and a fixed cavity 5. Sensor 1 is fixedly installed in fixed cavity 4, and sensor 2 is fixedly installed in fixed cavity 5. A terminal 6 and a terminal 7 are provided on the outer wall of the integrated chamber 3. Terminal 6 connects to sensor 1, and terminal 7 connects to sensor 2. External circuitry can be connected to sensors 1 and 2 within the integrated chamber 3 via terminals 6 and 7. Terminals 6 and 7 can be posts or contacts, passing through the side wall of the integrated chamber 3 and connecting to the corresponding terminals of sensors 1 and 2, respectively. The integrated chamber 3 integrates sensors 1 and 2 together. The integrated chamber 3 is attached to the object being measured, and the vibration is transmitted through the integrated chamber 3 to sensor 1 and sensor 2 for measurement.

[0032] Compared to sensor 2, sensor 1 has a wider measurement range but relatively lower sensitivity. When detecting vibration frequencies with complex characteristics, within the common measurable frequency range, the measurement result is taken from the higher sensitivity of sensor 2. Beyond the measurable frequency range of sensor 2, the measurement result is taken from the measurement result of sensor 1. Specifically, when the output data from sensors 1 and 2 match, the vibration frequency is considered to be within their common measurable frequency range. In this case, the data from sensor 2, with its higher sensitivity, is used to obtain higher data accuracy. When the output data from sensors 1 and 2 deviate significantly within a certain time range, it indicates that the frequency at that moment exceeds the measurement frequency range of sensor 2, and the measurement data from sensor 2 has been distorted. In this case, the data from sensor 1, with its wider measurement range, is used to ensure data accuracy. Thus, by integrating sensors 1 and 2, both high-sensitivity measurements within a specific range and a wider frequency measurement range can be achieved, avoiding data distortion caused by some data exceeding the measurement range of sensor 2. By integrating sensor 1 and sensor 2 into the integrated module 3, it is easy to install them as a single unit at the same detection position, eliminating the need for users to arrange them separately. Terminal 6 and terminal 7 also facilitate connection to external circuits, making the entire product convenient to use and highly practical.

[0033] In this embodiment, based on Figure 2 and Figure 3 As shown, sensor 1 and sensor 2 have the same upper electrode 8 and lower electrode 9. Sensor 1 also includes an intermediate electrode 10, and sensor 2 includes an intermediate electrode 11. Intermediate electrodes 10 and 11 have the same frame 12 and cantilever beams 14. Both intermediate electrodes 10 and 11 also have mass blocks 13, which are mounted within their respective frame 12 via corresponding cantilever beams 14. The number and arrangement of cantilever beams 14 in intermediate electrode 10 are the same as those in intermediate electrode 2, but the mass of mass block 13 in intermediate electrode 10 is less than that in intermediate electrode 2. Since they are all of the same specification, the only difference between sensor 1 and sensor 2 is the mass of mass block 13. That is, the higher resonant frequency of sensor 1 is achieved solely through the difference in the mass of mass block 13, facilitating integrated production.

[0034] In this design, the mass block 13 in intermediate electrode 10 has a vertically penetrating vent 15 at its center, and the mass block 13 in intermediate electrode 2 has a vertically penetrating vent 16 at its center. The mass blocks 13 in intermediate electrode 10 and intermediate electrode 2 have the same outer perimeter dimensions, but the size of vent 15 is larger than the size of vent 16. The identical outer perimeter dimensions mean that their shape, length, width, and thickness are all the same. The mass blocks 13 in intermediate electrode 10 and intermediate electrode 2 differ only in size through vent 15 and vent 16. This ensures that intermediate electrodes 10 and 2 can be connected to the outer perimeter of mass blocks 13 of different masses using the same frame 12 and cantilever beam 14, with the same connection arrangement. This means that the only difference between sensor 1 and sensor 2 is the size of vent 15 and vent 16, facilitating production and industrialization. Meanwhile, the arrangement of vent 15 and vent 2 16 allows air to flow easily between the top and bottom of the mass block 13, reducing the restriction on the movement of the mass block 13 caused by air resistance and improving the sensitivity of the measurement.

[0035] Furthermore, based on Figure 1 As shown, it also includes a shock absorber 17. The integrated chamber 3 includes a chamber body 18 and a chamber body 2 19. A fixing cavity 4 is located in chamber body 18, and a fixing cavity 2 5 is located in chamber body 2 19. A wiring terminal 6 is located on the outer wall of chamber body 18, and a wiring terminal 7 is located on the outer wall of fixing cavity 2 5. Sensor 1 is inserted into fixing cavity 4 by interference fit, and sensor 2 is inserted into fixing cavity 2 5 by interference fit. Chamber body 18 is fixedly connected to chamber body 2 19 by shock absorber 17. To improve the stability of the connection, sensor 1 and sensor 2 can also be reinforced by adhesive bonding to chamber body 18 and chamber body 2 19 respectively. The shock absorber 17 can be made of materials that can isolate vibration, such as rubber or polyurethane. Since all components in Sensor 1 and Sensor 2 are identical except for the mass of mass block 13, and the interference fit makes it easy for vibrations to be transmitted between Sensor 1 and housing 18, and between Sensor 2 and housing 29, resonance may occur in components of Sensor 1 and Sensor 2 in complex vibration environments, causing measurement distortion. By isolating housing 18 and housing 29 with vibration damper 17, the vibration of the measured object is transmitted to Sensor 1 through housing 18, and to Sensor 2 through housing 29. The vibration transmission between housing 18 and housing 2 is relatively small, thus reducing the mutual influence of vibrations between Sensor 1 and Sensor 2 and minimizing resonance.

[0036] Furthermore, based on Figure 4As shown, the bottom walls of both chamber 18 and chamber 29 are fitting walls 20 for contacting the object being measured. The fitting walls 20 are attached to the object, allowing vibrations to be better transmitted to sensor 1 and sensor 2 through the fitting walls 20. In this embodiment, the fitting walls 20 of chamber 18 and chamber 29 are flush, enabling both chambers 18 and 29 to simultaneously adhere to a flat surface, making it suitable for objects with flat surfaces.

[0037] based on Figure 5 As shown, as an alternative in this embodiment, the fitting walls 20 of the first chamber 18 and the fitting walls 20 of the second chamber 19 are arranged at different heights to be suitable for the test object with a stepped surface.

[0038] Furthermore, based on Figure 3 and Figure 6 As shown, both the first fixed cavity 4 and the second fixed cavity 5 have openings at the top. The frame 12 in the first intermediate electrode 10 and the frame 12 in the second intermediate electrode 11 are provided with exhaust channels 1-21 and 2-22, respectively. Exhaust channel 1-21 communicates with the top side of the corresponding mass block 13, and exhaust channel 2-22 communicates with the bottom side of the corresponding mass block 13. Flow channels 23, connecting to the corresponding exhaust channels 1-21 and 2-22, are opened from the top of the inner wall of the first fixed cavity 4 and the inner wall of the second fixed cavity 5. When the mass block 13 vibrates up and down, the gas at the top and bottom of the mass block 13 communicates with the outside through the exhaust channels and flow channels 23, achieving a balance of air pressure at the top and bottom of the mass block 13, reducing the restriction of the mass block 13's movement due to air resistance, and improving measurement accuracy. Simultaneously, since the flow channel 23 extends vertically, it combines with exhaust channels 1-21 and 2-22 to form an L-shaped ventilation structure, preventing foreign objects such as dust from entering the interior of sensor 1 and sensor 2.

[0039] Example 2:

[0040] This embodiment provides an accelerometer with dual detection bodies, which differs from Embodiment 1 in that the resonant frequencies of sensor 1 and sensor 2 are distinguished in a different way.

[0041] In this embodiment, based on Figure 7 and Figure 8As shown, sensor 1 and sensor 2 have the same upper electrode 8 and lower electrode 9. Sensor 1 also includes an intermediate electrode 10, and sensor 2 includes an intermediate electrode 11. Intermediate electrodes 10 and 11 have the same frame 12, the same mass block 13, and several cantilever beams 14. The mass block 13 is installed within the corresponding frame 12 via the corresponding cantilever beams 14. The number of cantilever beams 14 in intermediate electrode 10 is greater than the number of cantilever beams 14 in intermediate electrode 2. In this embodiment, intermediate electrode 10 has four cantilever beams 14, and intermediate electrode 2 has two cantilever beams 14. Thus, sensor 1 achieves higher stiffness than sensor 2 through a larger number of cantilever beams 14, resulting in a higher frequency measurement range and lower sensitivity compared to sensor 2. Of course, the number of cantilever beams 14 can be adjusted arbitrarily according to actual conditions, as long as the number of cantilever beams 14 in sensor 1 is greater than the number of cantilever beams 14 in sensor 2. The same specifications are exactly the same. The only difference between sensor 1 and sensor 2 is the number of cantilever beams 14, which facilitates production integration.

[0042] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An accelerometer with dual detection bodies, characterized in that: It includes sensor one, sensor two and an integrated chamber. Both sensor one and sensor two are capacitive accelerometers, and the resonant frequency of sensor one is higher than that of sensor two. The integrated chamber has a fixed cavity one and a fixed cavity two. Sensor 1 is fixedly installed in the fixed cavity 1, and sensor 2 is fixedly installed in the fixed cavity 2. The outer wall of the integrated compartment is provided with terminal 1 and terminal 2. Terminal 1 is connected to sensor 1, and terminal 2 is connected to sensor 2.

2. The accelerometer with dual detection bodies as described in claim 1, characterized in that: The sensor one and the sensor two have upper electrodes and lower electrodes of the same specifications. The sensor one also includes an intermediate electrode one, and the sensor two also includes an intermediate electrode two. The intermediate electrode one and the intermediate electrode two have frame and cantilever beam of the same specifications. Both the first intermediate electrode and the second intermediate electrode also have a mass block, which is installed in the corresponding frame through the corresponding cantilever beam. The number and arrangement of the cantilever beams in the first intermediate electrode are the same as those in the second intermediate electrode. The mass of the mass block in the first intermediate electrode is less than the mass of the mass block in the second intermediate electrode.

3. The accelerometer with dual detection bodies as described in claim 2, characterized in that: The mass block in the first intermediate electrode has a vertically penetrating vent hole 1 in its center, and the mass block in the second intermediate electrode has a vertically penetrating vent hole 2 in its center. The mass blocks in the first intermediate electrode and the mass blocks in the second intermediate electrode have the same outer circumferential dimensions, and the size of the vent hole 1 is larger than the size of the vent hole 2.

4. The accelerometer with dual detection bodies as described in claim 1, characterized in that: The sensor one and the sensor two have upper electrodes and lower electrodes of the same specifications. The sensor one also includes an intermediate electrode one, and the sensor two also includes an intermediate electrode two. The intermediate electrode one and the intermediate electrode two have a frame of the same specifications, a mass block of the same specifications, and several cantilever beams of the same specifications. The mass block is installed in the corresponding frame through the corresponding cantilever beam. The number of cantilever beams in the intermediate electrode one is greater than the number of cantilever beams in the intermediate electrode two.

5. The accelerometer with dual detection bodies as described in claim 2, 3, or 4, characterized in that: It also includes shock absorbers. The integrated compartment includes a compartment body one and a compartment body two. The fixed cavity one is located in the compartment body one, the fixed cavity two is located in the compartment body two, the wiring terminal one is located on the outer side wall of the compartment body one, and the wiring terminal two is located on the outer side wall of the fixed cavity two. The first sensor is embedded in the first fixed cavity through an interference fit, the second sensor is embedded in the second fixed cavity through an interference fit, and the first chamber is fixedly connected to the second chamber through the shock absorber.

6. The accelerometer with dual detection bodies as described in claim 5, characterized in that: The bottom walls of both chamber one and chamber two are fitting walls designed to fit against the object being tested.

7. The accelerometer with dual detection bodies as described in claim 6, characterized in that: The fitting wall of the first compartment is flush with the fitting wall of the second compartment.

8. The accelerometer with dual detection bodies as described in claim 6, characterized in that: The fitting walls of the first and second compartments are arranged at different heights.

9. The accelerometer with dual detection bodies as described in claim 2, 3, or 4, characterized in that: Both the first fixed cavity and the second fixed cavity are open at the top. The frame of the first intermediate electrode and the frame of the second intermediate electrode are provided with exhaust channel one and exhaust channel two. The first exhaust channel is connected to the top side of the corresponding mass block, and the second exhaust channel is connected to the bottom side of the corresponding mass block. A flow channel is provided from the top of the inner wall of the first fixed cavity and the inner wall of the second fixed cavity to the corresponding exhaust channel one and exhaust channel two.

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