CN111982265A - Packaging structure of two-dimensional vibration sensor based on fiber grating - Google Patents

Abstract

The invention discloses an encapsulation structure of a two-dimensional vibration sensor based on fiber grating. The encapsulation structure includes a casing, an elastic body, a first optical fiber grating and a second optical fiber grating. The elastic body includes a mass block located at the upper end and a hinge located in the middle. Part and base, the first fiber grating and the second fiber grating are pasted in the grooves of the mass block and the base under the action of prestress, and the grating area is suspended and distributed between the mass block and the base. The upper half of the mass is a hemisphere, the lower half is a cylinder, and the middle hinge part includes two orthogonally arranged hinges. The outer shape of the casing is a cuboid, a blind hole is arranged in the middle, a concave boss and a threaded hole are arranged at the bottom, and the side of the boss is rectangular. It solves the problems that the two-dimensional vibration sensor package is not easy to determine the measurement direction during installation, the installation stability is not high, and the optical signal loss is easy to occur.

Description

A package structure of a two-dimensional vibration sensor based on fiber grating

technical field

The invention belongs to the technical field of fiber grating vibration sensors, and particularly relates to a packaging structure of a two-dimensional vibration sensor based on fiber gratings.

Background technique

The two-dimensional vibration sensor based on fiber grating has the characteristics of anti-electromagnetic interference, high reliability, and easy reuse. It is one of the hot spots in the research and application of fiber grating. However, at present, many vibration sensors based on FBG design are mostly packaged in cylindrical housings for measurement needs. The sensor adopts such a packaging method. When installing the sensor in experiments and measurement applications, the installation surface is narrow, and the measurement direction of the sensor cannot be accurately determined, resulting in a large systematic error in the measurement result, which is not conducive to accurate measurement. Moreover, each fiber grating on most FBG-based two-dimensional sensors is connected with a jumper, which occupies one channel during the demodulation process, and fails to exert the characteristics of fiber grating multiplexing, which is not conducive to signal expansion.

The patent CN201611157807.1 designs a fiber grating two-dimensional vibration sensor with adjustable range, which is packaged in a cylindrical shell, and an auxiliary mechanism needs to be designed during installation, and the measurement direction of the sensor cannot be accurately determined, and the installation stability is not high , prone to installation errors. Patent CN201711229418.X designs a small fiber grating two-dimensional vibration sensor. When the optical fiber is packaged, it needs to be bent, and the bending radius is small, which is easy to cause the loss of optical signal.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a package structure of a two-dimensional vibration sensor based on fiber grating, which solves the problem that the two-dimensional vibration sensor package is not easy to determine the measurement direction during installation, the installation stability is not high, and the optical signal loss is easy to occur. question.

The technical solution adopted by the present invention to solve the technical problem is to provide a packaging structure of a two-dimensional vibration sensor based on a fiber grating. The mass block at the upper end, the hinge part and the base in the middle, under the action of prestress, the first fiber grating and the second fiber grating are pasted in the groove of the mass block and the base, and the grid area is suspended between the mass block and the base. between.

According to the above technical solution, the upper half of the mass block is a hemisphere, the lower half is a cylinder, and the middle hinge part includes two orthogonally arranged hinges.

According to the above technical solution, the outer shape of the casing is a cuboid, a blind hole is arranged in the middle, a concave boss and a threaded hole are arranged at the bottom, and the side of the boss is rectangular.

According to the above technical scheme, four optical fiber sticking grooves are evenly distributed on the cylindrical surface of the base, the side of the lower circular table is rectangular, and the positions of the corresponding grooves are evenly distributed with four small through holes. fiber optic slot.

According to the above technical solution, the grooves on the elastic body are on the surface of the mass block and the cylindrical part of the base, the holes on the base are distributed corresponding to the positions of the grooves and the aperture is larger than the width of the grooves.

According to the above technical solution, before the first fiber grating and the second fiber grating are pasted, the coating layer on the surface of the optical fiber in the grid region is removed by an organic solvent, and the remaining part of the fiber grating that is not pasted is passed through the hole in the lower part of the base, and one end It is wound from the upper hemisphere of the mass block to the opposite side of the fiber grating, pasted in the corresponding groove, and then passed through the hole in the lower part of the base.

According to the above technical solution, the elastic body is installed in the casing, the diameter of the blind hole is larger than the diameter of the cylinder of the elastic body, the boss is matched with the lower circular platform of the base, and the two rectangular sides overlap.

According to the above technical solution, it also includes a sensor packaging head, the sensor packaging head is a hollow shell, and the unpasted parts of the first fiber grating and the second fiber grating are directly penetrated into the sensor packaging head after passing through the hole in the lower part of the base, The optical fiber protective sleeve goes out; the shell, the elastomer and the sensor package head are all made of metal materials.

According to the above technical solution, the sensor packaging head is in the shape of a funnel, and the uppermost end thereof is provided with a thread.

According to the above technical solution, the sensor packaging head and the housing are connected by screw threads, and the elastic body is compressed at the same time.

The beneficial effects that the present invention produces are:

1) The optical fiber of the sensor is completely encapsulated in the metal shell, which is not easy to be damaged, and the package size is small and the structure is simple.

2) The fiber grating removes the surface coating of the grating region and its adjacent fibers before pasting. When loading and pasting, the fiber grating is firmly pasted. After unloading, the wavelength shift of the fiber grating changes little.

3) The measurement direction of the sensor is perpendicular to the surface of the adopted rectangular housing, and the measurement direction of the sensor can be marked on the surface of the housing.

4) The radius of the bending part of the optical fiber inside the sensor is large, and the transmission loss of the optical signal is low.

5) The fibers at both ends of the fiber grating go out from the sensor, and the two fibers can be connected in series to realize single-channel demodulation.

6) The outlet of the fiber grating is located at the bottom of the sensor, and the working stability is high.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings and embodiments, in which:

1 is an overall package structure diagram of a two-dimensional vibration sensor according to an embodiment of the present invention;

2 is a schematic structural diagram of a sensor housing in an embodiment of the present invention;

Figure 3 is a three view of an elastic body in an embodiment of the present invention;

Figure 4 is an axonometric view of an elastomer in an embodiment of the present invention;

Reference numerals: 1. Housing, 2. Elastomer, 3. First fiber grating, 4. Second fiber grating, 5. Sensor packaging head, 6. Fiber protection sleeve, 1-1. Blind hole, 1-2 .Boss, 1-3. Tapped hole, 2-1. Mass, 2-2. Hinged part, 2-3. Base.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention.

In the embodiment of the present invention, as shown in FIGS. 1-4 , a packaging structure of a two-dimensional vibration sensor based on fiber grating is provided. The packaging structure includes a housing 1 , an elastic body 2 , a first fiber grating 3 , and a second fiber grating. 4 Sensor packaging head 5, optical fiber protection sleeve 6, the outer shape of the outer casing is a cuboid, with a blind hole 1-1 in the middle, a concave boss 1-2 at the bottom and a threaded hole 1-3 with a certain depth, the boss 1-2 Some of the sides are rectangular. The elastic body includes a mass 2-1 at the upper end, a hinge part 2-2 at the middle, and a base 2-3 at the lowermost end. The upper half of the mass block 2-1 is a hemisphere, the lower half is a cylinder, and the diameter of the cylinder is slightly larger than the diameter of the hemisphere. The intermediate hinge portion 2-2 includes two orthogonally arranged hinges, the rotational directions of which are the x-direction and the y-direction, respectively. Four optical fiber sticking grooves are evenly distributed on the upper cylindrical surface of the base 2-3, the side surface of the lower circular table is rectangular, and the positions of the corresponding grooves are evenly distributed with four small through holes. The cylinder diameters of the mass block 2-1 and the base 2-3 are the same, corresponding to four grooves for affixing optical fibers evenly distributed. The sensor package head 5 is like a funnel, and its uppermost end is threaded. The casing 1, the elastic body 2 and the sensor package head 5 are all made of metal materials.

The grooves on the elastic body 2 are all along the z-axis direction, on the surfaces of the cylindrical parts of the mass block 2-1 and the base 2-3. The holes on the base 2-3 correspond to the position distribution of the grooves and the hole diameter is larger than the groove width. Before the first fiber grating 3 and the second fiber grating 4 are pasted, it is necessary to use an organic solvent to remove the coating layer on the surface of the optical fiber near the gate area and its vicinity, and then paste them on the mass blocks 2-1 and 2-1 under the action of prestress. In the groove of the base 2-3, the axial direction of the fiber grating is parallel to the z-axis direction, and the grid region is suspended and distributed between the mass block 2-1 and the base 2-3. For the remaining unpasted part of the fiber grating, one end is directly passed through the hole in the lower part of the base 2-3, and the other end is wound from the upper hemisphere of the mass block 2-1 to the opposite side of the fiber grating, pasted in the corresponding groove, and then also from the upper hemisphere of the mass block 2-1. Pass through the holes in the lower part of the base 2-3. The radial direction of the first fiber grating 3 is parallel to the x-axis, and the radial direction of the second fiber grating 4 is parallel to the y-axis.

The elastic body is installed in the shell 1, the diameter of the blind hole 1-1 is larger than the diameter of the cylinder of the elastic body 3, the boss 1-2 is matched with the lower circular platform of the base 2-3, the two rectangular sides overlap, and the circular platform is slightly higher than the depth of the boss. The sensor packaging head 5 is connected with the housing 1 by screws, and at the same time, the elastic body 2 is pressed tightly to prevent the elastic body 3 from moving in the z direction. The optical fiber protective sleeve 6 is pasted on the end of the sensor package head 5 by industrial glue. The sensor encapsulation head 4 is a hollow shell, and the unpasted parts of the first fiber grating 3 and the second fiber grating 4 pass through the holes in the lower part of the base 2-3, and then directly penetrate into the sensor encapsulation head 4, and are finally protected from the optical fiber. The casing 6 is passed out.

The specific implementation steps are as follows:

S1: Soak the fiber grating and the fibers on both sides with an organic solvent to remove its coating.

S2: Load the fiber grating, and stick the fiber grating between the mass block of the elastomer and the base at the same time, so that the fiber grating is in a suspended state. The hemisphere on the upper part of the block is wound around 180°, pasted in the groove on the opposite side of the fiber grating, and then pierced through the corresponding hole on the base.

S3: Put the elastomer into the shell, and the rectangular side of the lower circular table of the elastomer base coincides with the rectangular side of the boss in the shell.

S4: Connect the optical fiber protective sleeve to the tail end of the sensor package head through industrial glue.

S5: Connect the sensor packaging head to the housing through screw connection, wherein the sensor packaging head presses the elastomer when connecting, and the optical fiber finally passes through the sensor packaging head and protrudes from the optical fiber protective sleeve.

It should be understood that, for those skilled in the art, improvements or changes can be made according to the above description, and all these improvements and changes should fall within the protection scope of the appended claims of the present invention.

Claims (10)

1. An encapsulation structure of a two-dimensional vibration sensor based on a fiber grating, characterized in that the encapsulation structure comprises a casing, an elastic body, a first fiber grating and a second fiber grating, and the elastic body comprises a mass block at the upper end, a Under the action of prestress, the first fiber grating and the second fiber grating are pasted in the groove of the mass block and the base, and the grating area is suspended and distributed between the mass block and the base. 2 . The package structure of a two-dimensional vibration sensor based on fiber grating according to claim 1 , wherein the upper half of the mass block is a hemisphere, the lower half is a cylinder, and the middle hinge part includes two orthogonally arranged hinges. 3 . 3. The encapsulation structure of a two-dimensional vibration sensor based on fiber grating according to claim 1 or 2, characterized in that the outer shape of the casing is a cuboid, a blind hole is arranged in the middle, and a concave boss and a threaded hole are arranged at the bottom, The sides of the boss portion are rectangular. 4. the encapsulation structure of the two-dimensional vibration sensor based on fiber grating according to claim 1 or 2, it is characterized in that, four optical fiber sticking grooves are evenly distributed on the cylindrical surface of the base, the side surface of the lower circular platform is rectangular, and the corresponding grooves are Four small through holes are evenly distributed in position, and the cylinder diameter of the mass block base is the same, corresponding to four grooves for affixing optical fibers. 5. The encapsulation structure of a two-dimensional vibration sensor based on fiber grating according to claim 1 or 2, wherein the groove on the elastic body is on the surface of the mass block and the cylindrical portion of the base, and the hole on the base corresponds to the position of the groove distributed and the aperture is larger than the slot width. 6. The package structure of the two-dimensional vibration sensor based on fiber grating according to claim 1 or 2, characterized in that, before the first fiber grating and the second fiber grating are pasted, the coating on the surface of the optical fiber in the grid region is removed by an organic solvent. Coating, the remaining unpasted part of the fiber grating, one end goes out from the hole in the lower part of the base, and the other end is wound from the upper hemisphere part of the mass block to the opposite side of the fiber grating, pasted in the corresponding groove, and then out of the hole in the lower part of the base Inside out. 7. The encapsulation structure of the two-dimensional vibration sensor based on fiber grating according to claim 1 or 2, wherein the elastomer is installed in the casing, the diameter of the blind hole is larger than the diameter of the cylinder of the elastomer, and the lower part of the boss and the base. The round table is matched, and the sides of the two rectangles are coincident. 8. The packaging structure of the two-dimensional vibration sensor based on fiber grating according to claim 1 or 2, characterized in that, further comprising a sensor packaging head, the sensor packaging head being a hollow shell, the first fiber grating and the second optical fiber The unpasted part of the grating is pierced through the hole in the lower part of the base and then directly penetrates into the sensor packaging head, and passes through the optical fiber protective sleeve; the shell, the elastomer and the sensor packaging head are all made of metal materials. 9 . The packaging structure of a two-dimensional vibration sensor based on fiber grating according to claim 1 or 2 , wherein the sensor packaging head is funnel-shaped, and the uppermost end thereof is provided with threads. 10 . 10 . The package structure of the two-dimensional vibration sensor based on fiber grating according to claim 9 , wherein the sensor package head is connected with the housing by screws, and the elastic body is compressed at the same time. 11 .

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