JP4015652B2 - Optical fiber displacement meter - Google Patents

Description

  The present invention relates to a displacement meter that can measure regardless of the magnitude of the position displacement in the measurement displacement direction of a measurement object, and can also measure a remote measurement object.

Conventionally, the displacement of a measurement object is measured by an electric displacement meter such as a capacitance change type or a resistance change type (for example, Non-Patent Document 1) or a displacement meter using a CCD camera (for example, see Non-Patent Document 2). I was measuring. Capacitance change type displacement meter outputs the change in capacitance generated between the electrode moving in synchronization with the position of the measurement point and the electrode fixed in the displacement meter as a voltage change. (For example, refer to Patent Document 1). The resistance change type displacement meter is a displacement meter that specifies the amount of displacement of the measurement point by changing the resistance of the resistor installed in the displacement meter in synchronization with the position of the measurement point and outputting it as a change in voltage or current. . A displacement meter using a CCD camera is a displacement meter that calculates a displacement amount by processing an image taken by a CCD camera with a computer.
Japanese Patent Laid-Open No. 06-241706 http: // www. kyowa-ei. co. jp / japanes / product / 2002-10 / 10-33. pdf http: // www. obayashi. co. jp / news / newrelease / news200108 / news20010823. html

  However, the conventional electrical displacement meter uses an electric circuit to measure the displacement of the measurement point, so it is easily affected by external factors such as lightning strikes and high voltage cables, and multipoint measurement of remote measurement points is possible. In some cases, the system has a problem of becoming complicated. Further, a displacement meter using a CCD camera has a problem that it is difficult to measure in bad weather or at night.

  An object of the present invention is to provide a displacement meter that is not easily affected by these external factors, and that can easily measure the position displacement of a measurement object even when measuring a remote measurement point at multiple points. is there.

  In order to solve the above-mentioned problems, the optical fiber displacement meter according to the first invention of the present application is capable of moving in a linear direction on the pedestal, a fixed support fixed to the pedestal, and the fixed support on the pedestal. A movable support, one end fixed to the pedestal, the other end connected to the movable support to drive the movable support in the linear direction, connected to the measurement object, and the measurement object A piston that converts the position displacement of the measured displacement direction into a reciprocating motion, a cylinder that contains a fluid that transmits the reciprocating motion of the piston to the bellows, and is stretched between the fixed support and the movable support. And an optical fiber that generates strain by tension corresponding to the movement of the movable support.

  Specifically, the first invention of the present application converts the position displacement of the measurement object in the measured displacement direction into the reciprocating motion of the piston, and transmits the reciprocating motion to the bellows by the fluid. The measurement object is measured by moving the movable support corresponding to the displacement of the measurement object in the measurement displacement direction and applying a tension corresponding to the movement of the movable support to the optical fiber. It is an optical fiber displacement meter that measures the positional displacement in the displacement direction as strain generated in the optical fiber.

  In the first invention of the present application, even when the measurement object is located at a remote place or when an optical cable displacement meter cannot be installed at the measurement point of the measurement object, the measurement point of the measurement object and the optical cable The position displacement of the measurement object in the measured displacement direction can be measured by connecting the movable support of the displacement meter to the piston rod with a longer length. Even if the displacement of the object to be measured is large or small relative to the allowable elongation of the optical fiber, the amount of movement of the movable support can be reduced by adjusting the cylinder inner diameter and the inner diameter of the bellows. It can be measured according to tolerance.

  As described above, according to the first invention of the present application, since the displacement of the position of the measurement object is converted into the strain of the optical fiber, the displacement of the remote measurement object is easily measured without being affected by external factors. This simplifies the system. Furthermore, the measurement can be performed with improved accuracy in accordance with the amount of displacement of the measurement object and the tolerance of the extension of the optical fiber.

The optical fiber displacement meter of the second invention of the present application is a pedestal, a fixed support fixed to the pedestal,
A movable support that is movable in a linear direction on the pedestal from the fixed support, a measurement object, and the movable support are connected, and a position displacement of the measurement object in a measured displacement direction is connected to the movable support. A wire for converting the linear displacement to a position displacement in the linear direction, and an axial direction is applied to an optical fiber stretched between the fixed support and the movable support with a tension corresponding to the movement of the movable support. A means for imparting distortion is provided.

  Specifically, in the second invention of the present application, the measurement point of the measurement object and the movable support are connected by the wire, and the position displacement of the measurement object of the measurement object is measured by the movable support. An optical fiber displacement is measured by measuring the displacement of the measurement object in the measured displacement direction as a strain generated in the optical fiber by converting it into a moving amount and applying a tension corresponding to the movement of the movable support to the optical fiber. It is a total.

  In the second invention of the present application, even when the measurement object is located at a remote place or when an optical cable displacement meter cannot be installed at the measurement point of the measurement object, the measurement point of the measurement object and the optical cable The position displacement of the measurement object in the measured displacement direction can be measured by increasing the length of the wire and connecting to the movable support of the displacement meter.

  In addition, when the position displacement amount of the measurement object is large with respect to the allowable elongation of the optical fiber, the measurement point of the measurement object and the above-described point are measured via a spring member that causes the wire to absorb a part of the position displacement amount of the measurement object. By connecting the movable support, the amount of movement of the movable support can be measured in correspondence with the allowance of the extension of the optical fiber.

  As described above, according to the second invention of the present application, since the displacement of the position of the measurement object is converted into the strain of the optical fiber, the displacement of the remote measurement object can be easily measured without being affected by external factors. This simplifies the system. Furthermore, the measurement can be performed with improved accuracy in accordance with the amount of displacement of the measurement object and the tolerance of the extension of the optical fiber.

The optical fiber displacement meter of the third invention of the present application is a pedestal, a fixed support body fixed to the pedestal,
A movable support that is movable in a linear direction from the fixed support on the pedestal, is connected to the measurement object via a wire, and converts the position displacement of the measurement object in the measured displacement direction into a rotational motion. A rotating gear installed on the pedestal and provided with a reel for winding a wire, meshed with the rotating gear, and attached to the movable support that converts the rotational motion into a position displacement in the linear direction of the movable support. A linear gear in the linear direction, and means for applying an axial strain to an optical fiber stretched between the fixed support and the movable support with a tension corresponding to the movement of the movable support. It is characterized by providing.

  Specifically, the third invention of this application converts the position displacement of the measurement object in the measured displacement direction into the rotational motion of the rotating gear, and attaches the linear gear meshing with the rotating gear by the rotating motion. The amount of movement of the movable support is converted to the amount of movement of the movable support, the tension corresponding to the amount of movement of the movable support is applied to the optical fiber, and the displacement of the measurement object in the measured displacement direction is defined as the strain generated in the optical fiber. An optical fiber displacement meter to be measured.

  In the third invention of the present application, the diameter of the rotary gear and the reel attached to the rotary gear for winding the wire is adjusted even when the amount of displacement of the measurement object is large or small relative to the allowable elongation of the optical fiber. By doing so, the amount of movement of the movable support can be measured in correspondence with the allowable elongation of the optical fiber.

  Furthermore, even when the measurement object is in a remote place or when an optical cable displacement meter cannot be installed at the measurement point of the measurement object, the gap between the measurement point of the measurement object and the rotating gear By increasing the length of the wire and connecting it, it is possible to measure the positional displacement of the measurement object in the measured displacement direction.

  As described above, according to the third invention of the present application, since the displacement of the measurement object is converted into the strain of the optical fiber, the position displacement of the remote measurement object is easily measured without being influenced by external factors. This can simplify the system. Furthermore, the measurement can be performed with improved accuracy in accordance with the amount of displacement of the measurement object and the tolerance of the extension of the optical fiber.

  In the optical fiber displacement meter according to the first invention, the second invention, and the third invention of the present application, the strain of the optical fiber is connected to the optical fiber and the measurement is performed to measure the Brillouin scattered light due to the strain generated in the optical fiber. It is desirable to measure with a measuring instrument. By measuring with the measuring device that measures the Brillouin scattered light, the strain generated in the optical fiber can be easily measured, and the position displacement of the measurement object in the measured displacement direction can be easily recognized.

  Furthermore, in the optical fiber displacement meter according to the first invention, the second invention, and the third invention of the present application, the optical fiber may be stretched by reciprocating a plurality of times between the fixed support and the movable support. desirable. Since the strength against the tension applied by the movable support is increased by reciprocating and stretching the optical fiber a plurality of times, the optical fiber displacement meter is difficult to break. Furthermore, since the length of the optical fiber is increased, the intensity of the Brillouin scattered light due to the strain generated in the optical fiber is increased, making it easier to measure the strain of the optical fiber, and accurately measuring the position displacement of the measurement object in the measured displacement direction. Can be recognized.

  The optical fiber displacement meter according to the present invention converts the position displacement of an object to be measured into optical fiber strain and measures the Brillouin scattered light of the optical fiber. Even in the case of multipoint measurement, the position displacement of the measurement object can be measured easily.

  Hereinafter, the best mode for carrying out the present invention will be shown and described in detail, but the present invention is not construed as being limited to these descriptions.

(Embodiment 1)
FIG. 1 is a schematic view showing an embodiment of an optical fiber displacement meter according to the first embodiment of the present application. The optical fiber displacement meter 101 includes a pedestal 10, a fixed support 11, a movable support 12, a carriage 12 a, a bellows 13, a piston 14, a cylinder 15, a fluid 16, an optical fiber 17, a guide rail 18, and a pipe 19. Further, a measuring instrument 51 is connected to the optical fiber displacement meter 101, and a calculator 52 is connected to the measuring instrument 51.

  The pedestal 10 is a base serving as a reference for the origin of the optical fiber displacement meter. The material of the base 10 is not particularly limited, but plastic or metal that is not deformed by an external force and an internal force is desirable.

  The fixed support 11 is a support that is fixed to the base 10 in order to stretch the optical fiber 17.

  The movable support 12 is a support for stretching the optical fiber 17, and is placed on a carriage 12 a that can move in a linear direction from the fixed support 11 along the guide rail 18 installed on the base 10. Installed.

  The material of the fixed support 11 and the movable support 12 is not particularly limited, but concrete, plastic, or metal that supports the optical fiber 17 and does not deform so as to withstand the tension applied to the optical fiber 17 is desirable. Also, a cylindrical shape or a conical shape is desirable so that the optical fiber 17 is not subjected to bending load when the optical fiber 17 is supported.

  The guide rail 18 is a straight rail installed on the base 10 in order to move the movable support 12 linearly. The material of the guide rail 18 is not particularly limited, but a metal having wear resistance is desirable.

  The carriage 12a preferably has a rotating body such as a roller or a wheel so that the carriage 12a can move along the guide rail 18 without resistance. The material of the carriage 12a is not particularly limited, but a metal having wear resistance is desirable.

  The bellows 13 is a telescopic tube having one end fixed to the pedestal 10 and the other end connected to the movable support 12, and is a means for driving the movable support 12 along the guide rail 18. It is desirable that the maximum elongation of the bellows 13 be an allowable elongation of the optical fiber 17. The material of the bellows 13 is not particularly limited, but is desirably a fluororesin, polypropylene, or metal that is durable to the fluid 16 and does not leak the fluid 16.

  The piston 14 includes a piston ring 14 b that prevents a fluid 16 from leaking by reducing a gap between the piston rod 14 a and the inner wall of the cylinder 15. The piston 14 is arranged so that the reciprocating direction of the piston 14 is the measured displacement direction of a measurement object (not shown). The opposite end of the cylinder 15 of the piston rod 14a is connected to the measurement point of the measurement object. The piston 14 is a means for converting the position displacement of the measurement object in the measured displacement direction into a reciprocating motion and transmitting it to the fluid 16. The material of the piston rod 14a is not particularly limited. However, since the position displacement of the measurement object in the measured displacement direction is accurately transmitted to the fluid 16, there is no elasticity, and the weather resistance is good even when the measurement object is outdoors. It is desirable that the metal has properties. The material of the piston ring 14b is not particularly limited, but is preferably rubber or resin that is durable to the inner wall of the cylinder 15 and the fluid 16 and does not leak the fluid 16.

  The cylinder 15 is a container that contains the fluid 16 and is connected to the bellows 13 via a pipe 19. Although the material of the cylinder 15 is not particularly limited, it is durable to the fluid 16, there is no leakage of the fluid 16, and the position displacement of the measurement object in the measured displacement direction is accurately transmitted to the movable support 12. A metal that does not expand or contract is desirable. In the optical fiber displacement meter 101 in FIG. 1, when the position displacement of the measurement object in the measured displacement direction is displaced in a direction away from the optical fiber displacement meter 101, the bellows 13 extends and the movable support 12 is fixed. The pipe 19 is arranged in the cylinder 15 so as to move in a direction away from the support 11, but when the displacement of the measurement object in the measured displacement direction is displaced in a direction approaching the optical fiber displacement meter 101, The pipe 19 may be arranged in the cylinder 15 so that the bellows 13 extends and the movable support 12 is moved away from the fixed support 11.

  The material of the pipe 19 is not particularly limited. However, the pipe 19 is durable to the fluid 16 and does not leak, and the displacement of the measurement object in the measured displacement direction is accurately transmitted to the movable support 12. It is desirable to use a metal or hydraulic hose that does not shrink.

  As the fluid 16, a gas such as air or nitrogen can be used. However, in order to accurately transmit the reciprocating motion of the piston 14 to the bellows 13 through the pipe 19, a non-stretchable liquid such as oil or water may be used. desirable.

  The optical fiber 17 is an optical fiber stretched between the fixed support 11 and the movable support 12. As the optical fiber 17, a silica optical fiber, a glass optical fiber, or a plastic optical fiber used for communication can be used, and the diameter of the optical fiber is not particularly limited. It is desirable that the length of the optical fiber 17 is increased and the fixed support 11 and the movable support 12 are reciprocated a plurality of times and stretched. Since the strength against the tension applied by the movable support 12 is increased by reciprocating and stretching the optical fiber 17 a plurality of times, the optical fiber 17 is hardly damaged. Further, since the length of the optical fiber 17 is increased, the intensity of the Brillouin scattered light due to the strain generated in the optical fiber 17 is increased, and the distortion of the optical fiber 17 is easily measured. Can be recognized accurately.

  The measuring instrument 51 is connected to the optical fiber 17 and is a measuring instrument that measures a change in strain generated in the optical fiber 17.

  When monochromatic light is incident on one end of an optical fiber, part of it is scattered (Brillouin scattering) due to crystal change in the optical fiber due to strain in the optical fiber, and part of it returns to the incident direction. Have. Furthermore, this Brillouin scattering is a change in the wavelength of the Brillouin scattered light from the wavelength of the incident light in accordance with the strain amount of the optical fiber (hereinafter, the “wavelength shift” refers to the change in the wavelength of the Brillouin scattered light from the wavelength of the incident light. ). The measuring device 51 may be a measuring device such as a BOTDR (Brillouin Optical Time Domain Reflectometer) or an optical spectrum analyzer that measures the Brillouin scattered light.

  BOTDR is a measurement method that measures Brillouin scattered light and identifies the position and amount of strain generated in the optical fiber. That is, pulse time of monochromatic light such as laser is incident on the optical fiber, and the time and the amount of wavelength shift until the reflected light of Brillouin scattering is detected are measured. The position of strain generated in the optical fiber can be specified from the time until the reflected light is detected and the speed of light in the optical fiber, and the amount of strain generated in the optical fiber is specified from the amount of wavelength shift. be able to.

  Since the strain present in the optical fiber 17 changes due to the tension applied by the movement of the movable support 12 to the optical fiber 17, until the reflected light of the Brillouin scattering is detected corresponding to the position and magnitude of the strain. The time and the amount of wavelength shift change. Therefore, by measuring the amount of movement of the movable support 12 and the amount of wavelength shift due to the distortion of the optical fiber 17 by the BOTDR measuring instrument in advance, the interphase result is stored in the computer 52, and the position of the measurement object is thus measured. The amount of movement of the movable support 12 can be specified from the change in the amount of wavelength shift measured by the BOTDR measuring instrument when measuring the displacement. Since BOTDR can measure the presence and position of optical fiber strain, if optical fibers of multiple optical fiber displacement meters that measure the positional displacement of multiple measurement points are connected in series, each measurement can be performed with a single measuring instrument. Multiple points can be measured simultaneously, and the system can be simplified.

  An optical spectrum analyzer can also be used as the measuring device 51. An optical spectrum analyzer is a measuring device that analyzes the wavelength component of light. Using this, it is possible to specify the total amount of strain existing in the longitudinal direction of the optical fiber. That is, monochromatic light such as laser is incident on the optical fiber, and the reflected light of Brillouin scattering is measured with an optical spectrum spectrometer. By comparing the wavelength of incident light and the wavelength of reflected light of Brillouin scattering, the amount of distortion generated in the longitudinal direction of the optical fiber can be specified from the wavelength shift amount. Since the intensity of the reflected light of Brillouin scattering measured by the optical spectrum spectrometer is related to the length of the optical fiber, the longer the length of the optical fiber, the more accurately the strain of the optical fiber can be measured. Conversely, when the sensitivity of the optical spectrum spectrometer is high, the length of the optical fiber can be shortened.

  Since the strain due to the movement of the movable support 12 is applied to the optical fiber 17, the strain existing in the optical fiber 17 changes, so that the wavelength of the reflected light of Brillouin scattering changes from the wavelength of the incident light corresponding to the strain. To do. Accordingly, the shift amount of the movable support 12 and the wavelength shift between the reflected light of the Brillouin scattering of the optical fiber 17 and the incident light by the optical spectrum spectrometer are measured in advance, and the interphase result is stored in the computer 52. Thus, the amount of movement of the movable support 12 can be identified from the amount of wavelength shift of the reflected light of Brillouin scattering measured by the optical spectrum spectrometer when measuring the position displacement of the measurement object.

  The computer 52 calculates the correlation between the movement amount of the movable support 12 measured in advance and the measurement result of the wavelength shift amount measuring device 51 due to distortion of the optical fiber (hereinafter, the movement amount of the movable support 12 and the optical fiber 17). The amount of movement of the movable support 12 is specified from the measurement result transferred from the measuring device 51 based on the relationship between the phase shift of the wavelength shift amount due to the distortion of the measuring device 51 and the measurement result of the measuring device 51. It is a computer to do.

  The optical fiber displacement meter 101 operates as follows. A positional displacement generated in the direction of measurement displacement of a measurement object (not shown) is transmitted to a fluid 16 contained in a cylinder 15 as a reciprocating motion of a piston 14 connected to the measurement object. The fluid 16 transmitted with the reciprocating motion passes through the pipe 19 connected to the cylinder 15 and drives the bellows 13. The bellows 13 moves the movable support 12 along the guide rail 18 from the fixed support 11 in the linear direction. As a result, the position displacement of the measurement object in the measured displacement direction is converted into the amount of movement of the movable support 12. Thereby, tension is given to the optical fiber 17 due to the movement of the movable support 12, and the strain corresponding to the amount of movement of the movable support 12, that is, the strain corresponding to the position displacement of the measurement object in the measured displacement direction. Will occur. The Brillouin scattered light generated corresponding to the strain generated in the optical fiber 17 is measured by the measuring device 51, and the measurement result is transferred to the computer 52. The computer 52 specifies the movement amount of the movable support 12 from the transferred measurement result based on the movement amount phase data measured in advance, and the position of the measurement object in the measured displacement direction from the movement amount of the movable support 12. Identify the displacement.

  Here, when the position displacement of the measurement object in the measured displacement direction is larger than the allowable elongation of the optical fiber 17, the inner diameter of the bellows 13 is made larger than the inner diameter of the cylinder 15, thereby moving the movable support 12. The amount can be made smaller than the moving amount of the piston 14, and the optical fiber can be prevented from being broken. On the other hand, when the position displacement of the measurement object in the measured displacement direction is small and the optical fiber 17 cannot be sufficiently distorted, the inner diameter of the bellows 13 is made smaller than the inner diameter of the cylinder 15 to thereby provide a movable support. The amount of movement of the body 12 can be made larger than the amount of movement of the piston 14, and even if the positional displacement is fine, the strain generated in the optical fiber 17 can be measured by the measuring device 51, and the measurement accuracy can be improved.

  As a result, the optical fiber displacement meter 101 converts the position displacement of the measurement object in the measured displacement direction into the strain of the optical fiber 17, so that it is not easily affected by external factors, and the displacement of the remote measurement object can be easily performed. Measurement can be performed, and the system can be simplified. Further, the positional displacement of the measurement object can be easily measured regardless of the size of the position displacement of the measurement object.

(Embodiment 2)
FIG. 2 is a schematic view showing an embodiment of an optical fiber displacement meter according to the second embodiment of the present application. The optical fiber displacement meter 102 includes a pedestal 10, a fixed support 11, a movable support 12, an optical fiber 17, a guide rail 18, a wire 21, a spring member 22, and a pulley 23. Further, a measuring instrument 51 is connected to the optical fiber displacement meter 102, and a calculator 52 is connected to the measuring instrument 51.

  Functions and operations of the base 10, the fixed support 11, the movable support 12, the optical fiber 17, and the guide rail 18 of the optical fiber displacement meter 102 are the same as those of the base 10 of the optical fiber displacement meter 101 described in the first embodiment. The functions and operations of the body 11, the movable support 12, the optical fiber 17, and the guide rail 18 are the same.

  The wire 21 is linearly connected to the movable support 12 and a measurement object (not shown) on the moving direction of the movable support 12 from the fixed support 11. Although the material of the wire 21 is not particularly limited, the position of the measuring object in the measured displacement direction is accurately transmitted to the movable support 12, so there is no expansion and contraction, and it can be used even when the measured object is outdoors. Aramid fibers and metal wires having properties are desirable.

  The pulley 23 changes the direction of the wire 21 connecting the point to be measured of the measurement target that is not on the moving direction of the movable support 12 from the fixed support 11 and the movable support 12, and the measurement target displacement of the measurement target. It is a member that transmits the positional displacement in the direction to the movable support 12. The pulley 23 may be installed on the pedestal 10 or may be installed on a fixed object between the measurement object and the movable support 12. It is desirable to use a metal pulley having a weather resistance and a wear resistance that can be used even when the object to be measured is outdoors.

  The spring member 22 is a member that connects the measurement object and the movable support 12 via the wire 21 or between the movable support 12. An elastic body such as a spring or rubber can be used for the spring member 22. When the pulley 23 is used, the spring member 22 is connected while avoiding the position of the pulley 23.

  The optical fiber displacement meter 102 operates as follows. The positional displacement generated in the measured displacement direction of the measurement object (not shown) is transmitted to the movable support 12 through the wire 21 connected to the measurement object. The positional displacement of the measurement object in the measured displacement direction transmitted by the wire 21 moves the movable support 12 along the guide rail 18 from the fixed support 11 in the linear direction. If the length of the wire 21 is increased, the measurement object and the movable support 12 are connected even when the displacement meter cannot be installed directly on the measurement object or the measurement object is in the distance. can do. Here, when the measured displacement direction of the measurement object is different from the moving direction of the movable support 12, the pulley 23 can be used to change the direction of the wire 21, which can be transmitted as the moving direction of the movable support 12. . Moreover, if the pulley 23 is used, the wire 21 can be installed avoiding the obstacle between the measurement object and the movable support 12, and the measurement object and the movable support 12 can be connected by the wire 21. it can. Thereby, the position displacement of the measurement object in the measured displacement direction is converted into the amount of movement of the movable support 12. Thereby, tension is given to the optical fiber 17 due to the movement of the movable support 12, and a distortion corresponding to the amount of movement of the movable support 12, that is, a distortion corresponding to the position displacement of the measurement object in the measured displacement direction. Arise. The Brillouin scattered light generated corresponding to the strain generated in the optical fiber 17 is measured by the measuring device 51, and the measurement result is transferred to the computer 52. The computer 52 specifies the movement amount of the movable support 12 from the transferred measurement result based on the movement amount phase data measured in advance, and specifies the position displacement of the measurement object in the measured displacement direction therefrom.

  Here, the wire 21 may be connected to the middle of the wire 21 or the movable support 12 via a spring member 22 having a predetermined spring constant. Since the spring member 22 absorbs part of the position displacement of the measurement object in the measured displacement direction, even if the position displacement amount of the measurement object in the measurement displacement direction is larger than the allowable elongation of the optical fiber 17. The moving amount of the movable support 12 can be reduced, and the optical fiber 17 can be prevented from being broken. In addition, the measurement accuracy can be improved by selecting the spring member 22 having an optimal spring constant from the relationship between the position displacement amount of the measurement object in the measured displacement direction and the allowable elongation amount of the optical fiber 17.

  Thereby, since the optical fiber displacement meter 102 converts the position displacement of the measurement object into the strain of the optical fiber, the displacement of the remote measurement object can be easily measured without being influenced by external factors. Further, the positional displacement of the measurement object can be easily measured regardless of the size of the position displacement of the measurement object.

  A pulley 23 is installed on the base 10, the direction of the wire 21 extending in the direction from the fixed support body 11 to the movable support body 12 is changed by 180 degrees, and the measurement object is in the direction from the movable support body 12 to the fixed support body 11. By connecting the object measurement point, the spring member 22 can be installed in parallel with the base 10 and the optical fiber displacement meter 102 can be reduced in size.

(Embodiment 3)
FIG. 3 is a schematic view showing an embodiment of an optical fiber displacement meter according to the third embodiment of the present application. The optical fiber displacement meter 103 includes a pedestal 10, a fixed support 11, a movable support 12, an optical fiber 17, a guide rail 18, a wire 31, a rotation gear 32, and a linear gear 33.

  Functions and operations of the base 10, the fixed support 11, the movable support 12, the optical fiber 17, and the guide rail 18 of the optical fiber displacement meter 102 are the same as those of the base 10 of the optical fiber displacement meter 101 described in the first embodiment. The functions and operations of the body 11, the movable support 12, the optical fiber 17, and the guide rail 18 are the same.

  The wire 31 is linearly connected to a position displacement measurement point of a measurement object (not shown) in the tangential direction of the reel 32a and the reel 32a. Similar to the optical fiber 102, when the position displacement measurement point of the measurement object is not in the tangential direction of the reel 32a, or when there is an obstacle between the position displacement measurement point of the measurement object and the reel 32a. It is preferable to use a pulley 23. Although the material of the wire 31 is not particularly limited, the position of the object to be measured in the direction of the object to be measured is accurately transmitted to the rotary gear 32, so there is no expansion and contraction and the weather resistance can be used even when the object to be measured is outdoors. An aramid fiber or metal wire having a wire is desirable.

  A linear gear 33 is attached to the movable support 12 in the same direction as the moving direction, and meshed with the rotating gear 32. The material of the linear gear 33 is not particularly limited, but is preferably a wear-resistant metal.

  The rotating gear 32 is provided with a reel 32a for winding the wire 31. The rotation gear 32 is fixed to the base 10. The rotating gear 32 meshes with the linear gear 33 so that the movable support 12 can move along the guide rail 18. The rotation gear 32 may be a combination of a plurality of gears based on the relationship between the position displacement amount of the measurement object in the measured displacement direction and the allowable extension amount of the optical fiber 17. The material of the rotating gear 32 is not particularly specified, but is preferably a wear-resistant metal.

  The rotation gear 32 and the linear gear 33 may be either a spur gear, a helical gear, or a helical gear, but in order to accurately transmit the position displacement of the measurement object in the measured displacement direction to the movable support 12, the meshing is performed. It is desirable to reduce the play (backlash).

  The optical fiber displacement meter 103 operates as follows. A positional displacement generated in the direction of displacement of the measurement object (not shown) is transmitted to the reel 32a through the wire 31 connected to the measurement object, and converted into a rotational motion of the rotary gear 32. The rotational movement drives the linear gear 33 that meshes with the rotary gear 32, that is, moves the movable support 12 along the guide rail 18 from the fixed support 11 in the linear direction. As a result, the position displacement of the measurement object in the measured displacement direction is converted into the amount of movement of the movable support 12. Thereby, tension is given to the optical fiber 17 due to the movement of the movable support 12, and the strain corresponding to the amount of movement of the movable support 12, that is, the strain corresponding to the position displacement of the measurement object in the measured displacement direction. Will occur. The Brillouin scattered light generated corresponding to the strain generated in the optical fiber 17 is measured by the measuring device 51, and the measurement result is transferred to the computer 52. The computer 52 specifies the movement amount of the movable support 12 from the transferred measurement result based on the movement amount phase data measured in advance, and specifies the position displacement of the measurement object in the measured displacement direction therefrom. .

  Here, when the position displacement of the measurement object in the measured displacement direction is larger than the allowable elongation amount of the optical fiber 17, the gear ratio of the rotating gear 32 is increased so that the movable support 12 is moved from the position displacement amount. The amount of movement can be reduced, and the optical fiber can be prevented from being broken. On the other hand, when the position displacement of the measurement object in the measured displacement direction is small and the optical fiber 17 cannot be sufficiently distorted, the movement of the movable support 12 can be performed by reducing the gear ratio of the rotating gear 32. Even if the amount can be increased and the positional displacement is minute, the strain generated in the optical fiber 17 can be measured by the measuring device 51, and the measurement accuracy can be improved.

  Thereby, since the optical fiber displacement meter 103 converts the position displacement of the measurement object into the strain of the optical fiber, the position displacement of the remote measurement object can be easily measured without being influenced by external factors. . Further, the positional displacement of the measurement object can be easily measured regardless of the size of the position displacement of the measurement object.

  The optical fiber displacement meter of the present invention can measure the distortion of buildings such as buildings, bridges, and tunnels, and can also be used for prediction of natural disasters such as earthquakes and landslides by measuring crustal deformation, fixing the measurement point It can also be used as a level difference measuring device by scanning without using it.

It is the schematic which shows 1st embodiment of the optical fiber displacement meter of this invention. It is the schematic which shows 2nd embodiment of the optical fiber displacement meter of this invention. It is the schematic which shows 3rd embodiment of the optical fiber displacement meter of this invention.

Explanation of symbols

101, 102, 103 Embodiment 10 of optical fiber displacement meter of the present invention Pedestal 11 Fixed support body 12 Movable support body 12a Cart 13 Bellows 14 Piston 14a Piston rod 14b Piston ring 15 Cylinder 16 Fluid 17 Optical fiber 18 Guide rail 19 Piping 21 Wire 22 Spring member 23 Pulley 31 Wire 32 Rotating gear 32a Reel 33 Linear gear 51 Measuring instrument 52 Computer

Claims (3)

A pedestal,
A fixed support fixed to the pedestal;
A movable support that is movable in a linear direction from the fixed support on the pedestal;
A bellows having one end fixed to the pedestal and the other end connected to the movable support so as to drive the movable support in the linear direction;
A piston that is connected to a measurement object and converts a position displacement of the measurement object in a measured displacement direction into a reciprocating motion;
A cylinder containing a fluid that transmits the reciprocating motion of the piston to the bellows;
An optical fiber that is stretched between the fixed support and the movable support and generates strain due to a tension corresponding to the movement of the movable support;
An optical fiber displacement meter comprising: The optical fiber displacement meter according to claim 1, further comprising a measuring device connected to the optical fiber and measuring Brillouin scattered light due to strain generated in the optical fiber. Optical fiber displacement sensor as claimed in claim 1 or 2 between you, characterized in that the stretched bridged by reciprocating a plurality of times of the optical fiber and the fixed support and the movable support.

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