CN207866237U - Beam type obliquity sensor - Google Patents

Abstract

The utility model relates to a beam-type inclination sensor. A heavy block is arranged at the suspension end of a cantilever beam. When the cantilever beam is inclined relative to the horizontal plane, the bending moment applied by the heavy block to the cantilever beam changes, and the strain of the cantilever beam also changes with the The change of the cantilever beam is detected by the strain gauge to obtain the change information of the inclination angle of the cantilever beam. The beam type inclination sensor provided by the utility model has high precision, is little affected by temperature changes, and has low manufacturing cost.

Description

Beam Inclination Sensor

technical field

The utility model relates to an inclination sensor, in particular to a beam-type inclination sensor.

Background technique

At present, there are various inclination sensors at home and abroad, such as MEMS (the abbreviation of Micro-Electro-Mechanical System) inclination sensors, fiber grating inclination sensors, optical inclination sensors (that is, photoelectric levels), etc.

Among them, the MEMS inclination sensor is an acceleration sensor using the principle of inertia, that is, the inclination measurement is realized by measuring the angle between the vertical axis of gravity and the sensitive axis of the acceleration sensor. It is characterized by high test accuracy and large measurement range. The disadvantages are Easily affected by temperature, the price is high.

Fiber Bragg grating inclination sensor measures the physical quantity that causes the change by measuring the wavelength change of light passing through the fiber Bragg grating, such as temperature, stress, strain, etc. Fiber Bragg grating inclination sensor needs to convert the measured physical quantity into inclination angle through physical conversion. The disadvantage is that the test accuracy is lower than that of the MEMS inclination sensor, it is greatly affected by temperature changes, the price is high, and it cannot measure multi-axial strain at the same time.

The photoelectric level meter uses the optical dividing head method, the polygonal prism method, etc. to measure the angle. It uses the linear CCD and the principle of photoelectric conversion to obtain direct digital signal output. Its advantage is that it has very good real-time performance, high precision, and large measurement range. Its disadvantage is that it is easily affected by environmental conditions such as rain and fog, and it needs to be tested on site, and the cost is high.

It can be seen that there is currently no inclination sensor with high precision, little influence from temperature changes, and low cost.

Utility model content

(1) Technical problems to be solved

In order to solve the above-mentioned problems in the prior art, the utility model provides a beam-type inclination sensor. A weight is arranged at the suspension end of the cantilever beam. When the cantilever beam is inclined relative to the horizontal plane, the bending moment exerted by the weight on the cantilever beam changes, the strain of the cantilever beam also changes, and then the strain gauge detects the strain to obtain the change information of the inclination angle of the cantilever beam. The beam type inclination sensor provided by the utility model has high precision, is little affected by temperature changes, and has low manufacturing cost.

(2) Technical solution

In order to achieve the above object, the main technical solutions adopted by the utility model include:

A beam-type inclination sensor comprising:

base;

a cantilever beam having opposed first and second ends and opposed first and second sides, the first end is fixed to the base and the second end is freely suspended, The first side and/or the second side have a predetermined angle α with the vertical downward direction;

a weight having a predetermined mass m disposed at the end of the second end; and

At least one strain gauge, the strain gauge is arranged on the first side and/or the second side near the first end, and has a predetermined distance L from the center of gravity of the weight, for detecting the The strain change of the cantilever beam due to the change of the component force F of the gravity of the weight in the horizontal direction.

Preferably, in the beam-type inclination sensor, the predetermined included angle α is greater than 0°.

Preferably, in the beam-type inclination sensor, the base has a mounting groove or a mounting hole, and the cantilever beam has a mounting portion, and the mounting portion is adapted to the mounting groove or mounting hole.

Preferably, the beam-type inclination sensor further includes: a fixing piece, through which the cantilever beam is fixed to the installation groove or the installation hole.

Preferably, in the beam-type inclination sensor, the base is composed of a left base and a right base, a part of the installation groove or installation hole is provided in the left base, and another part is provided in the right base. The base, the combination of the two forms the installation groove or the installation hole; the installation part is embedded in the installation groove or the installation hole, the fixing part is a bolt, and the bolt passes through the installation groove or the installation hole. Separate through holes clamp the mounting portion to the base.

Preferably, in the beam-type inclination sensor, the cantilever beam is metal.

Preferably, in the beam-type inclination sensor, a plurality of strain gauges are symmetrically arranged on the first side and the second side of the cantilever beam.

(3) Beneficial effects

The beneficial effects of the utility model are: the beam-type inclination sensor of the utility model includes a cantilever beam with a preset suspension angle, and a weight arranged at the suspension end of the cantilever beam. Gravity exerts a base bending moment on the fixed end of the cantilever beam, and the corresponding base strain at the fixed end of the cantilever beam is detected by the strain gauge; when the cantilever beam is tilted relative to the horizontal plane, the gravity of the weight in the vertical direction exerts real-time pressure on the cantilever beam As the bending moment changes, so does the real-time strain at the fixed end of the cantilever. The real-time strain at the fixed end of the cantilever beam is detected by the strain gauge, and compared with the base strain, the information on the change of the tilt angle of the cantilever beam can be obtained. This kind of structural setting converts the small inclination angle change into the strain change of the beam structure. While significantly improving the inclination angle detection accuracy, the traditional strain test technology can be used, so that the sensor is greatly reduced by the influence of temperature changes, and the cost can be reduced. .

Description of drawings

Fig. 1 is the working principle schematic diagram of the present utility model;

Fig. 2 is another working principle schematic diagram of the utility model;

Fig. 3 is the structural representation (front sectional view) of an embodiment of the utility model;

Fig. 4 is the I-I direction sectional view of Fig. 3;

Fig. 5 is a schematic structural view (front view) of another embodiment of the present invention.

[Description of Reference Signs]

1: cantilever beam;

2: heavy block;

3: strain gauge;

4: Base;

5: Connecting bolts;

6: Fix the bolt.

Detailed ways

In order to better explain the utility model and facilitate understanding, the utility model will be described in detail below through specific implementation modes in conjunction with the accompanying drawings.

As shown in Figure 1, the working principle of the beam-type inclination sensor provided by the utility model is as follows: a cantilever beam 1 fixed at one end and suspended at the other end at an angle α is provided at the suspended end of a cantilever beam 1 with a mass of m and a weight of G 2, then the component force F in the horizontal direction of the weight 2 acting on the second end of the cantilever beam 1 is:

F=Gtanα.

The bending moment M, stress σ and strain ε of the weight 2 acting on the first end of the cantilever beam 1 with a rectangular cross section are respectively:

M = FL cos α;

Among them, W is the flexural section modulus of the beam body where the strain gauge is pasted, b is the width of the beam body where the strain gauge is pasted, h is the thickness of the beam body where the strain gauge is pasted, and E is the elastic modulus of the material used in the beam .

As shown in Figure 2, when the beam-type inclination sensor provided by the utility model follows the rigid movement of its fixed structure and is inclined at an angle β relative to the horizontal plane, the weight 2 acts on the second end of the cantilever beam 1 in the horizontal direction. The force F' is:

F'＝G tan(α+β)

The bending moment M', stress σ' and strain ε' of the weight 2 acting on the first end of the cantilever beam 1 with a rectangular cross section are respectively:

M'=F'Lcos(α+β);

The strain increment is:

A plurality of strain gauges are arranged at the fixed end of the cantilever beam 1 and the plurality of strain gauges form an electric bridge, then the change of the inclination angle of the cantilever beam relative to the horizontal plane can be indirectly monitored and detected by detecting the strain of the beam body.

It should be noted that the above formulas take a beam with a rectangular cross-section as an example. During specific implementation, beam bodies with circular, elliptical, and cross-sections of various desired shapes can be provided according to testing requirements.

Similarly, during specific implementation, beam bodies of various materials such as metal or non-metal may be provided according to test requirements. Especially considering the requirements of rain resistance and corrosion resistance in the field installation environment, anti-corrosion surface treatment can be carried out on the beam body made of metal.

Similarly, in actual implementation, a weight that can better apply a bending moment to the beam body can be set according to the test requirements, and the material, external contour and shape of the weight can be flexibly selected.

Similarly, in specific implementation, when the cantilever beam is fixed on the structure to be measured, the cantilever beam can be installed on the base, and the base is installed on the structure to be tested. When it is on the base, the base and the beam body can be connected together by setting mutually compatible connectors on the base and the beam body respectively; the base and the beam body can also be integrated into one connected to the beam body.

The beam-type inclination sensor provided by the utility model amplifies the small change of the inclination angle into the strain change of the beam body, and while significantly improving the inclination detection accuracy, the influence of the temperature change on the inclination sensor is greatly reduced by using the traditional strain test technology , and the cost of the sensor can be reduced.

In order to enlarge the small change of the inclination angle into the strain change of the beam body, the size of the beam-type inclination sensor provided by the utility model is relatively large, so it is more suitable for applications where there is no limit to the installation size of the sensor and high precision requirements for the inclination angle test Occasions, such as inclination of bridge piers, relative settlement, deflection test of long-span bridges, etc.

In specific implementation, according to the allowable stress and strain of the selected beam body material and the measurement range of the inclination angle, the thickness h, width b, length L and weight G of the cantilever beam can be designed and calculated according to the above formula, that is, Realize accurate and convenient measurement of the inclination angle of the structure to be tested.

Correspondingly, when the cross-section of the beam body is rectangular everywhere, the weight adopts a cuboid shape with matching dimensions.

As shown in Fig. 3 and Fig. 4, the beam type inclination sensor of an embodiment of the present invention comprises a base 4, a cantilever beam 1, and the cantilever beam 1 has opposite first ends and second ends, and opposite first sides and the second side, the first end is fixed to the base 1, the second end is freely suspended, the first side and/or the second side have a predetermined angle α with the vertical downward direction; the weight 2, the The weight 2 has a predetermined mass m and is arranged at the end of the second end; and four strain gauges 3 are symmetrically arranged on the first side and the second side near the first end, and the There is a predetermined distance L between the second ends, which is used to detect the strain change of the cantilever beam 1 due to the change of the component force F of the weight in the horizontal direction.

When the cantilever beam is compressed at a position close to the second end on the second side, the cantilever beam tends to be bent and deformed, and the first side and the second side are the compression surface and the tension surface respectively.

The four strain gauges 3 symmetrically arranged on the first side and the second side near the first end form a balanced bridge, which eliminates the influence of temperature changes on the one hand, and helps to eliminate the mutual interaction of the cross axes on the other hand. Therefore, the beam-type inclination sensor of the embodiment of the utility model has high precision, is little affected by temperature changes, can realize remote automatic testing, low cost, simple structure, and significantly improves the accuracy of inclination detection (accuracy can reach 5") .

The cantilever beam is preferably a thin-walled beam, the thin-walled beam defining a thickness h between the first side and the second side. Its thickness is selected according to the scale of the measured object and the numerical adaptability of the length L. The thin wall is selected to make the deformation of the cantilever more sensitive when the second end of the cantilever beam is compressed. In theory, under the same conditions, when the thickness The smaller , the greater the deformation of the cantilever caused by the pressure at the second end, and the more sensitive the device. Preferably the thickness h should therefore be much smaller than the length L.

In order to ensure good measurement accuracy, preferably, in the beam-type inclination sensor of the embodiment of the present invention, the predetermined included angle α between the cantilever beam and the vertical downward or vertical upward direction is greater than 0°.

When using the base 4 to install the cantilever beam 1 to the structure to be tested, in order to ensure good installation rigidity, a mounting groove or a mounting hole is provided on the base 4, and a mounting part is set on the cantilever beam. The slots or mounting holes are adapted so that the arm beam 1 can be mounted on the structure to be tested with sufficient rigidity.

When using the base 4 to install the cantilever beam 1 to the structure to be tested, in order to ensure the reliability of the installation, the base 4 is provided with a hole for passing the fixing bolt 5, and the cantilever beam 1 is firmly fixed by the fixing bolt 5 Between the left and right bases, the structure comprising the cantilever beam 1, the weight 2 and the base 4 is installed on the structure to be tested through the installation bolts 6.

Preferably, the cantilever beam 1 is fixed to the installation groove or installation hole by a fixing member. The fixing member can adopt various mechanical coupling forms.

As shown in Figures 3 and 4, the base 4 is composed of a left base and a right base, a part of the mounting groove or mounting hole is provided on the left base, and another part is provided on the right base, and the two are combined to form The installation groove or the installation hole; the installation part is embedded in the installation groove or the installation hole; the connecting bolt 5 passes through the through hole separated from the installation groove or the installation hole to clamp the installation part to the base.

In order to facilitate installation, processing and measurement, the beam body of the beam-type inclination sensor in the embodiment of the present invention has a rectangular cross-section and is made of a metal material with good ductility.

As shown in FIG. 5 , in actual implementation, it is also possible to realize that the cantilever beam has a preset inclination angle α with respect to the vertical downward direction by changing the installation angle of the sensor and the base. At this time, the preset inclination angle may not be set between the cantilever beam and its installation base, thereby simplifying the production process of the cantilever beam.

In summary, the beam-type inclination sensor of the present invention has the advantages of high precision, little influence by temperature changes, remote automatic testing, low cost, and simple structure through the beam-type structure design. Although its size is large, it can be used in places where the installation size is not limited and the accuracy of inclination testing is high, such as the inclination of bridge piers, relative settlement, and deflection testing of long-span bridges. Moreover, because these applications have the characteristics of high rigidity of the structure, their range requirements are small. For example, setting the range to 1° can meet the requirements, and the smaller range also helps to improve the test accuracy of the sensor.

The technical principles of the present utility model have been described above in conjunction with specific embodiments. These descriptions are only for explaining the principle of the utility model, and cannot be construed as limiting the protection scope of the utility model in any way. Based on the explanations here, those skilled in the art can think of other specific implementation modes of the present invention without creative efforts, and these modes will all fall within the protection scope of the present invention.

Claims (7)

1. a kind of beam type obliquity sensor, which is characterized in that it includes：

Pedestal；

Cantilever beam, the cantilever beam have opposite first end and second end and opposite first side and second side, institute State first end and be fixed on the pedestal, the second end freely suspends, the first side and/or second side with straight down Direction has predetermined angle α；

Pouring weight, the pouring weight have predetermined quality m, are set to the end of the second end；And

At least one foil gauge, the foil gauge are arranged in the first side and/or second side close to the first end Position, between the center of gravity of the pouring weight have preset distance L, for detecting the cantilever beam because the gravity of the pouring weight exists The variation of the component F of horizontal direction and the strain variation generated.

2. beam type obliquity sensor as described in claim 1, which is characterized in that

Predetermined angle α is more than 0 °.

3. beam type obliquity sensor as described in claim 1, which is characterized in that

The pedestal has mounting groove or a mounting hole, and the cantilever beam has a mounting portion, the mounting portion and the mounting groove or Mounting hole is adapted.

4. beam type obliquity sensor as claimed in claim 3, which is characterized in that further include：

Fixing piece, the cantilever beam are fixed on the mounting groove or mounting hole by the fixing piece.

5. beam type obliquity sensor as claimed in claim 4, which is characterized in that described

Pedestal is made of left pedestal and Right socle, and a part for the mounting groove or mounting hole is set to the left pedestal, another portion It is divided into the Right socle, the two combination constitutes the mounting groove or mounting hole；The mounting portion be embedded in the mounting groove or Mounting hole, the fixing piece are bolt, and the bolt passes through the perforation that is separated with the mounting groove or mounting hole by the peace Dress portion is clamped on the pedestal.

6. beam type obliquity sensor as described in claim 1, which is characterized in that

The cantilever beam is metal.

7. beam type obliquity sensor as described in claim 1, which is characterized in that

Multiple foil gauges are symmetrically disposed in the first side and second side of the cantilever beam.