An acceleration sensor

Abstract

The present disclosure provides an acceleration sensor, comprising a sensing unit, the sensing unit comprising: a support base; a cantilever beam comprising: a fixed part, a first vibrating arm and a second vibrating arm, the fixed part being fixed to the support base, the first vibrating arm and the second vibrating arm being in a suspended state in the vertical direction; the first vibrating arm comprising a first cantilever and a first mass block arranged on the first cantilever, the second vibrating arm comprising a second cantilever and a second mass block arranged on the second cantilever, the first cantilever and the second cantilever being respectively located on both sides of the fixed part; the cantilever beam further comprising a suspension area formed by a gap between a part of the first vibrating arm protruding from the fixed part and a part of the second vibrating arm protruding from the fixed part; a fiber grating comprising an optical fiber and a grating area of the optical fiber, two ends of the fiber grating being respectively fixed to the parts of the first vibrating arm and the second vibrating arm protruding from the fixed part, the grating area being located in the suspension area, and the fiber grating being located on the side away from the support base. The acceleration sensor of the present disclosure improves the sensitivity.

Description

Technical Field

[0001] This disclosure relates to an acceleration sensor. Background Technology

[0002] Fiber optic sensing technology is a novel technology that has emerged with the advancements in optical fibers and fiber optic communication. Interferometric fiber optic accelerometers use optical fibers as a medium, inheriting the advantages of optical fibers such as resistance to electromagnetic interference, light weight, and ease of multiplexing. Compared to traditional electrical accelerometers, they possess extremely high sensitivity and excellent dynamic response characteristics, enabling high-resolution and wide dynamic range detection when applied to demodulating dynamic vibration signals. Therefore, this technology is widely used in numerous fields such as earthquake and volcano monitoring, tsunami warning, and building structural health monitoring.

[0003] Currently, many fields have raised the demand for highly sensitive accelerometers, and there is an urgent need to improve the sensitivity of accelerometers. Utility Model Content

[0004] Therefore, the object of this disclosure is to provide an acceleration sensor. The acceleration sensor solves the aforementioned problems.

[0005] This disclosure provides a speed sensor, characterized in that it includes a sensing unit, the sensing unit comprising: a support base; a cantilever beam including: a fixed part, a first vibrating arm, and a second vibrating arm, the fixed part being fixed to the support base, the first vibrating arm and the second vibrating arm being suspended in the vertical direction; the first vibrating arm including a first cantilever and a first mass block disposed on the first cantilever, the second vibrating arm including a second cantilever and a second mass block disposed on the second cantilever, the first cantilever and the second cantilever being respectively located on both sides of the fixed part; the cantilever beam further includes a suspended region formed by the gap between the portion of the first vibrating arm protruding from the fixed part and the portion of the second vibrating arm protruding from the fixed part; a fiber optic grating including an optical fiber and a grating region located on the optical fiber, the two ends of the fiber optic grating being respectively fixed to the portions of the first vibrating arm and the second vibrating arm protruding from the fixed part, the grating region being located in the suspended region, and the fiber optic grating being located on the side away from the support base.

[0006] In one embodiment, the first mass block and the second mass block are respectively disposed on the side of the first cantilever and the second cantilever away from the support base, and the first mass block and the second mass block protrude from the fixing part; the suspended area is formed by the gap between the first mass block and the second mass block formed above the fixing part; the two ends of the fiber optic grating are respectively fixed to the first mass block and the second mass block.

[0007] In one embodiment, the thickness of the accelerometer is 2mm-5mm.

[0008] In one embodiment, the first mass block and the second mass block are respectively disposed on the side of the first cantilever and the second cantilever close to the support base; the side of the first cantilever and the second cantilever away from the support base protrudes from the fixed part, and the suspended area is formed by the gap between the portions of the first cantilever and the second cantilever protruding from the fixed part.

[0009] In one embodiment, the cantilever beam further includes: a support portion extending from one side of the first cantilever or the second cantilever protruding from the fixed portion toward the middle to be located above the fixed portion and spaced a certain distance from the fixed portion, the suspended area being formed by the gap between the support portion and the second cantilever or the first cantilever; or two support portions extending from one side of the first cantilever and the second cantilever protruding from the fixed portion toward the middle to be located above the fixed portion and spaced a certain distance from the fixed portion, the suspended area being formed by the gap between the two support portions.

[0010] In one embodiment, the length of the suspended area is 1mm-10mm.

[0011] In one embodiment, the system further includes a housing that encloses the sensing unit, and the support base is fixedly disposed within the housing.

[0012] In one embodiment, the fixing part is embedded in the support seat to fix the cantilever beam in the horizontal direction.

[0013] In one embodiment, the accelerometer includes at least two sensing units, which are used to measure acceleration at different locations, and the fiber Bragg gratings of the at least two sensing units are connected by fiber optic connectors.

[0014] In one embodiment, the acceleration sensor further includes a cantilever beam fixing component that covers the upper part of the fixing portion and is fixed to the support.

[0015] The accelerometer disclosed herein is equipped with two cantilever arms and two mass blocks. The two mass blocks simultaneously drive the same fiber Bragg grating to be stretched or compressed, thereby enhancing the stretching or compression of the fiber Bragg grating and improving the sensitivity of the accelerometer. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings of the embodiments of this disclosure will be briefly described below. The drawings are merely illustrative of some embodiments of this disclosure and are not intended to limit the scope of all embodiments of this disclosure. In the drawings:

[0017] Figure 1 A schematic diagram of the structure of an acceleration sensor according to a first embodiment of the present disclosure is shown;

[0018] Figure 2 A front view of an accelerometer sensor according to a first embodiment of the present disclosure is shown;

[0019] Figure 3 A bottom view of an acceleration sensor according to a first embodiment of the present disclosure is shown;

[0020] Figure 4 An AA cross-sectional view of an acceleration sensor according to a first embodiment of the present disclosure is shown;

[0021] Figure 5 A BB cross-sectional view of an accelerometer according to a first embodiment of the present disclosure is shown;

[0022] Figure 6 A schematic diagram of the cantilever beam structure of an accelerometer according to a first embodiment of the present disclosure is shown;

[0023] Figure 7 A front view of a cantilever beam for an accelerometer according to a first embodiment of the present disclosure is shown;

[0024] Figure 8 A top view of a cantilever beam for an accelerometer according to a first embodiment of the present disclosure is shown;

[0025] Figure 9 A schematic diagram of the structure of an accelerometer according to a second embodiment of the present disclosure is shown.

[0026] 1-Outer shell 2-Support base 3-Cantilever beam 31-Fixing part 32-First cantilever 33-Second cantilever 34-First support part 35-Second support part 36-Suspended area 41-First mass block 42-Second mass block 5-Fiber grating 51-Grate area 6-Fiber optic connector 7-Cantilever beam fixing component 8-Threaded mounting hole Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. The same reference numerals in the drawings represent the same components. It should be noted that the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0028] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” and similar terms used in this patent application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an” or “a” and similar terms do not necessarily indicate a quantity limitation. The terms “comprising,” “including,” or “having,” and similar terms mean that the element or object preceding the word encompasses the element or object listed following the word and its equivalents, without excluding other elements or objects. The terms “connected” or “connected,” and similar terms are not limited to the physical or mechanical connection or connection shown in the drawings, but may include equivalent connections or connections, whether direct or indirect. The terms “upper,” “lower,” “left,” and “right,” etc., are used only to indicate relative positional relationships, which may change accordingly when the absolute position of the described object changes.

[0029] like Figure 1-8 The acceleration sensor shown is a first embodiment of the present disclosure, including: a housing 1, a support base 2, a cantilever beam 3, a first mass block 41, a second mass block 42, and a fiber optic grating 5.

[0030] The cantilever beam 3 includes a fixing part 31, a first cantilever 32, a second cantilever 33, and a suspended area 36. The first cantilever 32 and the second cantilever 33 are located on both sides of the fixing part 31. The cantilever beam 3 is fixed to the support base 2 through the fixing part 31, and the first cantilever 32 and the second cantilever 33 are suspended in the vertical direction.

[0031] The sides of the first cantilever 32 and the second cantilever 33 that are away from the support base 2 protrude from the fixing part 31, and a gap, i.e., a suspended area 36, ​​is formed between the parts of the first cantilever 32 and the second cantilever 33 that protrude from the fixing part 31 above the fixing part 31. That is, the thickness of the first cantilever 32 and the second cantilever 33 on the side away from the support base 2 is greater than the thickness of the fixing part 31.

[0032] The first mass block 41 and the second mass block 42 are respectively disposed on the side of the first cantilever 32 and the second cantilever 33 near the support base 2, and can be disposed on the lower surface of the cantilever beam 3. The fiber optic grating 5 includes an optical fiber and a grating region 51 located on the optical fiber. The fiber optic grating 5 is fixed to the side of the first cantilever 32 and the second cantilever 33 away from the support base 2, that is, the upper surface of the cantilever beam 3, and its grating region 51 is located in the suspended region 36.

[0033] The mass block causes the cantilever to vibrate, thereby causing the fiber Bragg grating 5 to stretch or compress. Because two cantilever arms and two mass blocks are used, the two mass blocks simultaneously cause the same fiber Bragg grating to stretch or compress. Compared to an accelerometer with only one cantilever arm, the stretching or compression of the fiber Bragg grating caused by the same acceleration is doubled, thus improving the sensitivity of the accelerometer. Compared to an accelerometer with only one cantilever arm, the sensitivity of the accelerometer disclosed herein is doubled.

[0034] In one embodiment, the accelerometer sensor can be 3cm-5cm long, and the shapes of the first and second cantilever arms are not limited, for example, they can be circular. The cantilever length can be 1cm-3cm, and the length of the fixing part can be 0.6cm-2cm. To improve the sensor's sensitivity, the length of the cantilever arms or the density or mass of the mass block can also be increased.

[0035] To further improve sensitivity, the cantilever beam 3 may further include a first support portion 34 and a second support portion 35. The first support portion 34 extends from one side of the first cantilever 32 protruding from the fixed portion 31 towards the center, located above the fixed portion 31 and at a certain distance from it, forming a U-shaped opening with the fixed portion 31. The second support portion 35 extends from one side of the second cantilever 33 protruding from the fixed portion 31 towards the center, located above the fixed portion 31 and at a certain distance from it, forming a U-shaped opening with the fixed portion 31. A gap, i.e., a suspended area 36, ​​is formed between the second support portion 35 and the first support portion 34. This arrangement can reduce the rigidity of the connection between the fixed portion 31 and the first cantilever 32 and the second cantilever 33, improving the sensitivity of the cantilever beam to vibration; the height of the U-shaped opening can increase the rotation radius of the grid area 51 relative to the fixed portion 31, thereby improving the sensitivity of the accelerometer.

[0036] It is understandable that the accelerometer may not include the first support portion 34 and the second support portion 35, or may only include one support portion. The first support portion 34 and the second support portion 35 are used to fix the fiber Bragg grating 5. Due to the provision of the first support portion and the second support portion, the length of the suspended region 36 is reduced, thereby reducing the effective length of the fiber of the fiber Bragg grating 5 under stretching or compression, further improving the sensitivity of the accelerometer. The length of the gap between the first support portion 34 and the second support portion 35 can be determined according to the length of the grating region 51 of the fiber Bragg grating 5. The length of the grating region 51 can be 1mm, 2mm, or 5mm, and the corresponding length of the suspended region can be set to 1mm-10mm. Compared with not providing a support portion, the sensitivity is improved by 2-3 times.

[0037] In one embodiment, the fixing portion 31 of the cantilever beam is embedded in the support base 2 to fix the cantilever beam 3 in the horizontal direction and reduce horizontal swaying. Embodiments of this disclosure also include a cantilever beam fixing component 7, which covers the upper part of the fixing portion 31 of the cantilever beam and is fixed to the support base 2. That is, the cantilever beam fixing component 7 and the support base 2 clamp and fix the fixing portion 31 of the cantilever beam in the middle, for fixing the cantilever beam 3 to the support base 2. The fiber optic grating 5 and the grating region 51 are located above the cantilever beam fixing component 7.

[0038] In one embodiment, the accelerometer includes at least two sensing units, each used to measure acceleration at different locations. One sensing unit is connected to the fiber optic grating of another sensing unit via an optical fiber connector 6 at the end of its included fiber optic grating. The distance between multiple sensing units is not limited, and the length of the fiber optic grating 5 can be adjusted according to the distance requirements between the locations to be measured. This embodiment enables the measurement of acceleration at multiple different locations and demodulation within the same demodulation channel.

[0039] In one embodiment, the housing 1 may also be provided with threaded mounting holes 8 for fixing the acceleration sensor at the test position.

[0040] like Figure 9 The accelerometer shown is a second embodiment of the present disclosure, comprising: a housing 1, a support base 2, a cantilever beam 3, a first mass block 41, a second mass block 42, and a fiber optic grating 5. The cantilever beam 3 includes a fixing part 31, a first cantilever 32, a second cantilever 33, and a suspended area 36.

[0041] The difference between the accelerometer in the second embodiment and the first embodiment lies only in that the first mass block 41 and the second mass block 42 are respectively disposed on the side of the first cantilever 32 and the second cantilever 33 away from the support base 2, that is, they can be disposed on the upper surface of the first cantilever 32 and the second cantilever 33. A gap, i.e., a suspended region 36, is formed between the first mass block 41 and the second mass block 42 above the fixing part 31. The two ends of the fiber optic grating 5 are respectively fixed on the first mass block 41 and the second mass block 42, and the grating region 51 is located in the suspended region 36.

[0042] The accelerometer of the second embodiment of this disclosure has its volume effectively reduced by setting the first mass block 41 and the second mass block 42 on the upper surfaces of the first cantilever 32 and the second cantilever 33 respectively, and forming a suspended area 36 above the fixing part 31. In this embodiment, the thickness of the accelerometer can be reduced to 2mm-5mm, which is suitable for use in scenarios that require a small accelerometer, such as transformers.

Claims

1. An acceleration sensor, characterized in that, Includes a sensing unit, the sensing unit comprising: Support base; The cantilever beam includes: a fixed part, a first vibrating arm and a second vibrating arm, wherein the fixed part is fixed to the support base, and the first vibrating arm and the second vibrating arm are suspended in the vertical direction; The first vibrating arm includes a first cantilever and a first mass block disposed on the first cantilever, and the second vibrating arm includes a second cantilever and a second mass block disposed on the second cantilever. The first cantilever and the second cantilever are respectively located on both sides of the fixed part. The cantilever beam also includes a suspended area, which is formed by the gap between the portion of the first vibrating arm protruding from the fixed part and the portion of the second vibrating arm protruding from the fixed part; A fiber optic grating, comprising an optical fiber and a grating region located on the optical fiber, wherein the two ends of the fiber optic grating are respectively fixed to the portions of the first vibrating arm and the second vibrating arm that protrude from the fixing portion, the grating region is located in the suspended region, and the fiber optic grating is located on the side away from the support base.

2. The acceleration sensor according to claim 1, characterized in that, The first mass block and the second mass block are respectively disposed on the side of the first cantilever and the second cantilever away from the support base, and the first mass block and the second mass block protrude from the fixing part; The suspended area is formed by the gap between the first mass block and the second mass block, which is formed above the fixed part; The two ends of the fiber optic grating are fixed to the first mass block and the second mass block, respectively.

3. The acceleration sensor according to claim 2, characterized in that, The thickness of the accelerometer is 2mm-5mm.

4. The accelerometer according to claim 1, characterized in that, The first mass block and the second mass block are respectively disposed on the side of the first cantilever and the second cantilever close to the support base; The sides of the first cantilever and the second cantilever away from the support protrude from the fixed part, and the suspended area is formed by the gap between the portions of the first cantilever and the second cantilever that protrude from the fixed part.

5. The acceleration sensor according to claim 4, characterized in that, The cantilever beam also includes: The support portion extends from one side of the first cantilever or the second cantilever that protrudes from the fixed portion toward the middle to be located above the fixed portion and at a certain distance from the fixed portion; the suspended area is formed by the gap between the support portion and the second cantilever or the first cantilever. Alternatively, there may be two support portions, wherein the two support portions are respectively extended from one side of the fixed portion by the first cantilever and the second cantilever, and are located above the fixed portion and at a certain distance from the fixed portion, and the suspended area is formed by the gap between the two support portions.

6. The accelerometer according to claim 5, characterized in that, The length of the suspended area is 1mm-10mm.

7. The accelerometer according to claim 1, characterized in that, It also includes a housing that encloses the sensing unit, and the support base is fixedly disposed in the housing.

8. The accelerometer according to claim 1, characterized in that, The fixing part is embedded in the support seat to fix the cantilever beam in the horizontal direction.

9. The acceleration sensor according to claim 1, characterized in that, It includes at least two sensing units, which are used to measure acceleration at different positions, and the fiber Bragg gratings of the at least two sensing units are connected by fiber optic connectors.

10. The accelerometer according to claim 1, characterized in that, It also includes a cantilever beam fixing component, which covers the upper part of the fixing part and is fixed to the support.

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