JP4287765B2 - Shock detection optical fiber sensor and system using the same - Google Patents

Description

  The present invention relates to an impact detection optical fiber sensor for sensing an impact received by a measurement object, and a system using the same.

  In a conventional impact sensor, an electric sensor generally uses a pressure sensor, an acceleration sensor, and a strain gauge to detect pressure, acceleration, and strain due to impact.

  In the optical fiber type sensor, there is a sensor that detects an optical fiber by applying an impact such as pressure, acceleration, and strain to an optical fiber made of quartz or plastic, and changing the light amount by bending loss and compression loss. is there.

  Generally considered in the optical fiber system, an optical fiber is spirally wound around a soft cylindrical tube, and the loss of light increases as the bending radius of the optical fiber is reduced when the tube is deformed by the external force of a collision. There is a method for detecting collision and impact.

  The prior art document information related to the invention of this application includes the following.

Japanese Patent Laid-Open No. 9-26370 JP-A-5-249352 JP-T-2002-531812

  However, in the case of the electric shock sensor in the above-described prior art, since the shock is detected by an electric signal, the sensor itself is vulnerable to electromagnetic noise, and there is a problem that it is difficult to distinguish the signal to be detected from the noise.

  In addition, when transmitting the detection signal, there is a problem that the transmission line is susceptible to electromagnetic noise from the outside, and the influence of this noise cannot be ignored.

  There is also a problem that the electrical signal has a large transmission loss in the transmission path.

  In the case of optical fiber type using quartz, transmission loss of light occurs due to bending and compression, but due to the characteristics of the material quartz, the optical fiber causes mechanical strength deterioration due to bending and compression, and when an impact is applied There is also a problem that the quartz glass optical fiber may be cut.

  In the case of a plastic optical fiber, the possibility of being cut by bending or compression is low, but since the rigidity is strong, there is a problem that light transmission loss is hardly caused by bending or compression and the accuracy of the sensor is lacking.

  Accordingly, an object of the present invention is to provide a highly accurate impact detection optical fiber sensor which is resistant to electromagnetic noise and has little mechanical deterioration due to impact, and a system using the same.

  The present invention was devised to achieve the above object, and the first invention is a plastic optical fiber for detecting an impact, and a rubber covering the outer periphery of the plastic optical fiber with a predetermined thickness. Layer, a rack member formed into a bowl shape that exposes and accommodates the outer peripheral portion of the plastic optical fiber covered with the rubber layer along its longitudinal direction, and is formed and accommodated inside the rack member An impact detection optical fiber sensor comprising a convex member that deforms the plastic optical fiber according to an impact.

  In a second aspect of the invention, the rack member is provided along the longitudinal direction of the plastic optical fiber coated with the rubber layer, and the exposed portion of the plastic optical fiber faces the impact direction. is there.

  In a third aspect of the invention, the rack member is formed in a groove having a substantially U-shaped or substantially U-shaped cross section perpendicular to the groove longitudinal direction.

  In a fourth aspect of the invention, the plastic optical fiber is detachable with respect to the groove of the rack member.

In a fifth aspect of the invention, the rack member is formed of a hard plastic or a metal such as stainless steel or brass.

According to a sixth aspect of the present invention, the plastic optical fiber has a cross-linked acrylic resin as a core material and a fluororesin that does not transmit moisture as a cladding material.

In a seventh aspect of the present invention, a plurality of the convex members are provided in the groove longitudinal direction .

In an eighth aspect of the invention, the convex member is formed in a semi-cylindrical shape.

In a ninth aspect of the invention, the rubber layer is formed of ethylene propylene rubber.

According to a tenth aspect of the present invention, the plastic optical fiber is extended from the impact detection optical fiber sensor according to any one of the first to tenth aspects of the invention, and a light emitting element is connected to one of the plastic optical fibers and a light receiving element is connected to the other. The light from the light emitting element is incident on the plastic optical fiber, the light is received by the light receiving element, and the change in the amount of received light is detected to detect the distortion of the plastic optical fiber. An impact detection optical fiber sensor system that detects the impact received by the impact detection optical fiber sensor.

In an eleventh aspect of the invention, the plastic optical fiber is extended from the impact detection optical fiber sensor according to any one of the first to tenth aspects of the invention, and a light emitting element is connected to one of the plastic optical fibers and a light receiving element is connected to the other. , The light from the light emitting element is incident on the plastic optical fiber, the light is received by the light receiving element, the light quantity change of the received light is detected, and the speed of the measurement object to which the impact detection optical fiber sensor is attached, A light loss pattern corresponding to the weight and stiffness is obtained in advance from the change in the amount of light, the light loss pattern detected when receiving the impact is detected, and the light loss pattern is compared with the previously obtained light loss pattern. It is an impact sensing optical fiber sensor system that identifies speed, weight and stiffness.

  According to the present invention, it is possible to obtain a highly accurate impact detection optical fiber sensor that is resistant to electromagnetic noise and has little mechanical deterioration due to impact, and a system using the same.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the accompanying drawings.

  FIG. 1 is a block diagram showing an impact detection optical fiber sensor system 1 using an impact detection optical fiber sensor 10 according to a preferred embodiment of the present invention.

  As shown in the figure, the impact detection optical fiber sensor 10 includes a detection fiber 12a for detecting an impact in which a rubber layer 18 (see FIG. 4) having a certain thickness is coated on the outer periphery of a plastic optical fiber 12, and a longitudinal direction of the detection fiber 12a. , And a convex-shaped member that is formed inside the rack member 17 and that deforms the plastic optical fiber 12 that is accommodated in response to an impact. 19 (see FIG. 2, FIG. 3, FIG. 5).

  As shown in FIG. 4, the detection fiber 12a includes a core 15 having a high refractive index (for example, core diameter φ1.5 mm) and a clad 16 having a low refractive index provided around the core 15 (for example, clad diameter φ2.2 mm). A rubber layer 18 is coated at a constant thickness (for example, a coating thickness of 0.4 mm) on the outer periphery of the plastic optical fiber 12 made of

  As the detection fiber 12a, for example, an ethylene propylene-coated heat-resistant plastic optical fiber (EPHPOF) is used, and as an example, the core 15 includes a cross-linked acrylic resin (thermosetting acrylic resin), silicone. The clad 16 is formed of a heat-resistant plastic optical fiber 12 formed of a core material such as resin, and is formed of a clad material such as fluorine resin that does not transmit moisture. A rubber layer 18 such as ethylene propylene rubber having a predetermined hardness of around 45 (JIS K 7215 A type) is coated.

  The detection fiber 12a is arranged in a U-shape with respect to the measurement object 60 that detects an impact, and the detection fiber 12a of each linear portion is accommodated in the rack member 17 to constitute the sensor unit 10a. The

  As shown in FIG. 3A, the sensor portion 10a is a convex member on the bottom of the groove 17a of the rack member 17 having a groove 17a having a bowl shape, which is substantially U-shaped (or substantially U-shaped alphabet) in the drawing. 19 is provided, and the detection fiber 12a is removably incorporated in the groove 17a so as to protrude from the rack member 17 by an exposure amount h of a predetermined distance.

  As shown in FIG. 2, the convex member 19 is formed in a semi-cylindrical shape, and is formed integrally with the rack member 17 at a predetermined interval at the bottom of the groove 17a.

  The rack member 17 is made of hard plastic (having Rockwell hardness (JIS K 7202) R scale 118, M scale 80), brass (BS), stainless steel (SUS), or the like.

  As shown in FIG. 1, plastic optical fibers 12i and 12o (the rubber layer 18 may or may not be coated) extended from both ends of the detection fiber 12a disposed on the measurement object 60, respectively. The light emitting element 11 is connected to the end of one plastic optical fiber 12i, and the light receiving element 13 is connected to the end of the other plastic optical fiber 12o. An electric signal line 14 is connected to each of the light emitting element 11 and the light receiving element 13, and a power source (not shown) for supplying power to the light emitting element 11 and an impact detection (not shown) for processing the amount of light received by the light receiving element 13. Connected to the unit.

  Next, the operation of the present invention will be described.

  The light from the light emitting element 11 is always input to the detection fiber 12a, the light is received by the light receiving element 13 at the other end of the detection fiber 12a, and a change in the amount of light is detected. The impact applied to can be detected.

  FIG. 3A is a cross-sectional view showing a state in which the impact detection optical fiber sensor does not receive an impact.

  In a state where no impact is received, the detection fiber 12a is not subjected to any stress, and therefore, the core 15, the clad 16, and the rubber layer 18 are hardly distorted.

  As shown in FIGS. 2 and 3 (b), the impact applied to the measurement object 60 is a pressing force applied to the detection fiber 12a of the sensor unit 10a, whereby the lower portion of the detection fiber 12a is predetermined. Since it is in contact with the convex member 19 at an interval, it does not deform beyond the distance between the convex member 19 and the upper end of the rack member 17 at the location in contact with the convex member 19, and is in contact with the convex member 19. In the part which is not, it will be pushed in into the groove | channel 17a of the rack member 17. FIG. As a result, the detection fiber 12a is bent with the convex member 19 as a starting point due to the microbending effect of each convex member 19, so that bending loss and compression loss occur in the detection fiber 12a due to bending, resulting in transmission loss. Becomes larger.

  That is, when the sensor portion 10a of the impact detection optical fiber sensor 10 receives an impact in the direction of the arrow 33, stress is most effectively concentrated on the detection fiber 12a with a portion in contact with the convex member 19 as a fulcrum. 15, the transmission loss of the detection fiber 12a increases due to the strain generated in the clad 16 and the rubber layer 18. The increase in transmission loss reduces the amount of light passing through the detection fiber 12a.

  Since this transmission loss is related to the magnitude of the impact applied to the measurement object 60, the magnitude of the impact, the speed of the measurement object 60, etc. can be detected by measuring the change over time of the transmission loss.

  FIG. 6 is a diagram showing the change over time in the amount of light passing through the detection fiber 12a of the impact detection optical fiber sensor 10, that is, the amount of light received by the light receiving element 13, in which the horizontal axis indicates time and the vertical axis indicates the amount of received light y. The solid line is an embodiment of the present invention, the broken line is a conventional example in which an impact sensor is formed by sandwiching a plastic optical fiber between two plates, and each line shows a change with time when the same impact is applied. .

  When no impact is applied, the received light amount y is constant in both the present invention (solid line) and the conventional example (broken line), but when the impact is applied at time t1, the received light amount y decreases.

  In the conventional example, since there is no convex member, the stress generated in the sensor unit is dispersed in the optical fiber, so the strain generated in the sensor unit is small, and the detection of light loss due to the stress is small as shown by the broken broken line in the figure.

  In this case, in the present invention, since the R-shaped convex member gives the detection fiber a microbend, it is possible to obtain a larger transmission loss than in the conventional example, and the sensitivity for detecting the impact is increased, and the impact is more accurately detected. Can be detected.

  Further, when an impact is applied, the transmission loss reaches the maximum (light reception amount y is small) from time t1 at time t2, and then the light reception amount returns to the original value when the impact disappears at time t3. Therefore, by detecting the slope of the transmission loss (light reception amount y) from time t1 to time t2 and from time t2 to time t3, the speed, weight, stiffness, and the like at the time of different impacts applied to the measurement object 60 are identified. Can do.

  Accordingly, the state of change in light quantity (light loss pattern) at times t1 to t3 is stored in advance, and the change in received light amount (change in light loss) actually applied is compared with the previously stored light loss pattern. The speed, weight, stiffness, etc. at the time of impact applied to the measurement object 60 can be easily identified.

  That is, for example, even when an impact of the same magnitude is applied to the vehicle that is the measurement object 60, the change in the amount of light detected by the impact detection optical fiber sensor 10 mounted on the vehicle is represented by the traveling speed of the vehicle. Since the gradient and magnitude of the change in the amount of light in the medium are different, or the time t2 until reaching the peak is different, the obtained change in the amount of light becomes a unique light loss pattern corresponding to the speed.

  Even when an impact of the same magnitude is applied to an automobile, in the case where the mass of the automobile is different, the change in the amount of light detected by the impact detection optical fiber sensor 10 is caused by the inclination or magnitude of the change in the amount of light in the figure depending on the mass of the automobile. Or the time t2 until reaching the peak is different. That is, the change in the amount of light obtained becomes a unique light loss pattern corresponding to the mass of the automobile.

  In addition, even when the same impact is applied to the car, if the bumper or the body of the car is different, the change in the amount of light obtained will be a unique pattern corresponding to the firmness of the car body, etc. .

  As described above, in the present invention, when the impact is applied to the detection fiber 12a by the convex member 19, the microbend effect is applied to impart deformation according to the impact, but the detection fiber 12a from the rack member 17 is applied. The exposure amount h and the shape and size of the convex member 19 will be further described.

  FIG. 5 shows that when the detection fiber 12a has a core diameter of φ1.5 mm, a cladding diameter of φ2.2 mm, and a coating thickness of the rubber layer 18 as described above, the diameter of the detection fiber 12a is φ3.0 mm. The shape and dimension of the convex member 19 are shown.

  In the figure, the convex member 19 is a semi-cylinder with a radius of r = 1.8 mm, and the height of the portion where the semi-cylinder protrudes from the bottom of the groove 17a is an R shape (semi-circular curved surface). The interval between the convex members 19 may be, for example, a pitch P = 6.3 mm, and the exposure amount h is h = 1.2 mm. Can be detected.

  The convex member 19 can be selected in the range of radius r = 0.5 to 10 mm, height H = 0.1 to 5 mm, and exposure amount h in the range of h = 0 to 3 mm. The pitch P can also be selected in the range of P = 1 to 20 mm.

Next, reference examples of the present invention will be described.

FIG. 7 is a configuration diagram showing an impact detection optical fiber sensor system 2 using an impact detection optical fiber sensor 20 which is a reference example of the present invention.

  As shown in the figure, the impact detection optical fiber sensor 20 includes a plastic optical fiber 22 for detecting an impact, a flat plate member 27 (see FIGS. 9 and 10) provided along the longitudinal direction of the plastic optical fiber 22, and a flat plate. A convex member 29 (see FIGS. 9 and 10) that deforms the plastic optical fiber 22 provided on the member 27 according to an impact, and a cushion member 28 that covers the periphery of the plastic optical fiber 22 and the flat plate member 27. It is configured with.

  As shown in FIG. 8, the plastic optical fiber 22 includes a core 25 having a high refractive index (for example, core diameter φ1.5 mm) and a clad 26 having a low refractive index provided around the core 25 (for example, a cladding diameter φ2. 2 mm), which is an optical fiber for impact detection.

As an example, the plastic optical fiber 22 has a core 15 formed of a core material such as a cross-linked acrylic resin (thermosetting acrylic resin) or a silicone resin, and a clad 16 formed of a clad material such as a fluorine resin that does not transmit moisture. The plastic optical fiber 22 composed of the optical fiber is arranged in a U-shape with respect to the measurement object 60 for detecting an impact, and the plastic optical fiber 22 at each linear portion is a flat plate member 27. At the same time, the sensor part 20a is configured by being covered with the cushion member 28.

  As shown in FIG. 10A, the sensor unit 20a is provided with a flat plate member 27 along the longitudinal direction of the plastic optical fiber 22, and a convex member 29 is provided on one surface on which the plastic optical fiber 22 is provided. The plastic optical fiber 22 and the convex member 29 are in contact with each other, and the plastic optical fiber 22 and the flat plate member 27 are covered.

  As shown in FIG. 9, the convex member 29 is formed in a semi-cylindrical shape and is formed integrally with the flat plate member 27 at a predetermined interval.

  The convex member 29 may be the same as the shape / dimension and interval of the convex member 19 provided in the sensor portion 10a of the impact detection optical fiber sensor 10 (see FIG. 5).

  The flat plate member 27 is made of hard plastic (Rockwell hardness (JIS K 7202) R scale 118, M scale of about 80), brass (BS), stainless steel (SUS), or the like.

  As shown in FIG. 7, plastic optical fibers 22i and 22o extending from both ends of the plastic optical fiber 22 arranged on the measurement object 60 are extended, and light is emitted from one end of the plastic optical fiber 22i. The element 11 is connected, and the light receiving element 13 is connected to the end of the other plastic optical fiber 22o. Electrical signal lines 14 are connected to the light emitting element 11 and the light receiving element 13, respectively.

Next, the operation of the reference example of the present invention will be described.

  The light from the light emitting element 11 is always input to the plastic optical fiber 22, and the light receiving element 13 at the other end of the plastic optical fiber 22 receives the light and detects a change in the amount of the light, thereby measuring the object to be measured. An impact applied to the object 60 can be detected.

  FIG. 10A is a cross-sectional view showing a state in which the impact detection optical fiber sensor does not receive an impact.

  In a state where no impact is applied, the plastic optical fiber 22 is not subjected to any stress, so that neither the core 25 nor the clad 26 is distorted.

  The impact applied to the measurement object 60 is a pressing force applied to the plastic optical fiber 22 of the sensor unit 20a, as shown in FIGS. 9 and 10B. Is in contact with the convex member 29 at a predetermined interval. Therefore, the portion in contact with the convex member 29 is not deformed beyond the distance between the convex member 29 and the upper end of the cross section of the plastic optical fiber 22, and the convex shape. The portion that is not in contact with the member 29 is pushed into the flat plate member 27. As a result, the plastic optical fiber 22 is bent with the convex member 29 as a starting point due to the microbending effect of each convex member 29. Therefore, the plastic optical fiber 22 is distorted by bending, resulting in a large transmission loss. Become.

  That is, when the sensor portion 20a of the impact detection optical fiber sensor 20 receives an impact in the direction of the arrow 33, stress is most effectively concentrated on the plastic optical fiber 22 with the portion in contact with the convex member 29 as a fulcrum, Transmission loss of the plastic optical fiber 22 increases due to distortion generated in the core 25 and the clad 26. The increase in transmission loss reduces the amount of light passing through the plastic optical fiber 22.

  Since this transmission loss is related to the magnitude of the impact applied to the measurement object 60, the magnitude of the impact, the speed of the measurement object 60, etc. can be detected by measuring the change over time of the transmission loss.

FIG. 11 is a diagram showing the change over time of the light amount of the plastic optical fiber 22 of the impact detection optical fiber sensor 20 (that is, the amount of light received by the light receiving element 13), in which the horizontal axis represents time and the vertical axis represents the amount of received light. y indicates a solid example , a solid line is a reference example of the present invention, and a broken line is a conventional example in which a plastic optical fiber is sandwiched between two plates to form an impact sensor, and each line changes with time when the same impact is applied. Indicates.

  When no impact is applied, the received light amount y is constant in both the present invention (solid line) and the conventional example (broken line). However, when an impact is applied, the received light amount y decreases.

  In this case, in the impact detection optical fiber sensor 20, as in the impact detection optical fiber sensor 10, a micro-bend is given to the plastic optical fiber by the convex member, so that a large transmission loss can be obtained compared to the conventional example, Sensitivity to detect is increased, and impact can be detected more accurately.

  Similarly to the case of FIG. 6, by detecting the inclination of the transmission loss (light reception amount y), it is possible to identify the speed, weight, stiffness, and the like at the time of different impacts applied to the measurement object 60.

  Therefore, the state of light quantity change (light loss pattern) as shown in FIG. 11 is stored in advance, and the change in the amount of received light actually applied is compared with the light loss pattern stored in advance, so that the measurement object The speed, weight, stiffness, etc. at the time of impact applied to 60 can be easily identified.

  The sensor unit 20a is not limited to the structure shown in the drawing. For example, each sensor unit 20a shown in FIG. 9 uses one flat plate member 27. However, by using two flat plate members 27, the impact detection effect can be further enhanced. When the two flat plate members 27 are structured such that the surfaces on which the convex members 29 exist are opposed to each other and the plastic optical fiber 22 is sandwiched between the flat plate members 27, the plastic optical fiber has a higher bending strain and compressive strain. 22, the change in the light transmission loss of the sensor unit 20a becomes remarkable.

The operation of these reference examples is basically the same as that of the impact detection optical fiber sensor 10.

  Here, the impact detection optical fiber sensors 10 and 20 are not limited to the shapes shown in FIGS. In the figure, the sensor portions 10a and 20a are formed in a substantially straight line shape, and the detection fiber 12a and the plastic optical fiber 22 are bent most by the convex members 19 and 29 in a direction orthogonal to the longitudinal direction of the sensor portions 10a and 20a. The sensor units 10a and 20a have a structure that can most easily sense an impact from this direction.

  For example, by providing a plurality of sensor portions 10a and 20a in a circular arc shape, the impact detection optical fiber sensors 10 and 20 can detect an impact not only in one direction but also in multiple directions orthogonal to the arc. Also good.

  Further, instead of providing the convex member 19 on the rack member 17, the groove bottom portion of the rack member 17 and the surface of the groove side wall are formed in a corrugated shape, and come into contact with the mountain-shaped portion provided by the corrugation. As described above, the detection optical fiber 12a may be incorporated into the groove, and the undulating mountain-shaped portion may obtain the same effect as the convex member.

  Further, instead of providing the convex member 29 on the flat plate member 27, the surface of the flat plate member 17 is formed in a wave shape, and the plastic optical fiber 22 is in contact with a mountain-shaped portion provided by the waved surface. May be incorporated so that the corrugated mountain-shaped portion can obtain the same effect as the convex member.

  In the present invention, since the impact received by the change in the intensity of light passing through the detection fiber 12a and the plastic optical fiber 22 is detected, the impact is detected without being affected by electromagnetic noise in the vicinity of the impact detection optical fiber sensors 10 and 20. It is possible.

  Since the light emitting element 11 and the light receiving element 13 are optical components that perform electro-optical conversion, it is difficult to eliminate the influence of electromagnetic noise at all, but plastic light that is not affected by electromagnetic noise. By extending the fibers 12i, 12o, 22i, and 22o and providing the light emitting element 11 and the light receiving element 13 at locations away from the impact detection optical fiber sensors 10 and 20, the influence of electromagnetic noise can be ignored.

  Furthermore, the light emitting element 11 and the light receiving element 13 and the sensor units 10a and 20a can be installed in different places. For this reason, electromagnetic noise can be shielded by covering the light emitting element 11 and the light receiving element 13 with a metal plate or the like.

  By using the present invention, it is possible to eliminate the influence of electromagnetic noise and transmission loss, which were problems with conventional electric shock sensors.

  In addition, compared with an impact sensor using a silica glass optical fiber, the impact detection optical fiber sensors 10 and 20 according to the present invention are less susceptible to fatigue cutting of the plastic optical fibers 12 and 22 due to bending and compression, and are highly reliable sensors. The system can be configured.

  The impact detection optical fiber sensors 10 and 20 are more efficiently bent or compressed into the optical fiber due to the impact than the conventional impact sensor using the optical fiber. Therefore, the impact detection optical fiber sensors 10 and 20 are high-sensitivity sensors that can accurately detect the applied impact.

  Optical fibers 12 and 22 having a cross-linked acrylic resin as a core material and a fluororesin that does not transmit moisture as a cladding material are excellent in impact detection optical fiber sensors 10 and 20 that are not affected by electromagnetic noise and are resistant to moisture and the like. It can be used as a simple member.

  The impact detection optical fiber sensors 10 and 20 can detect multipoint and multidirectional impacts of the measurement object 60 by providing a plurality of sensor units 10a and 20a.

  Since the impact detection optical fiber sensors 10 and 20 have a structure having a convex member, it is possible to improve the sensitivity of impact detection.

  Further, the impact detection optical fiber sensor has a simple configuration and a structure that allows easy one-touch assembly, and a low-cost impact detection optical fiber sensor system that can be mass-produced can be easily realized.

It is a block diagram which shows the impact detection optical fiber sensor and system which are suitable implementation of this invention. It is explanatory drawing which shows the impact detection state of an impact detection optical fiber sensor. FIG. 3A is a cross-sectional view showing a state in which the impact detection optical fiber sensor does not receive an impact. FIG. 3B is a cross-sectional view showing a state in which the impact detection optical fiber sensor receives an impact. It is sectional drawing which shows the structure of the detection fiber used for the impact detection optical fiber sensor shown in FIG. It is sectional drawing which shows the cross section of the convex-shaped member provided in the groove bottom part. It is a time-dependent change figure which shows the change of the light quantity which passes the impact detection optical fiber sensor of this Embodiment, and the sensor of a prior art example. It is a general-view figure which shows the impact detection optical fiber sensor and system which are the reference examples of this invention. It is sectional drawing which shows the structure of the plastic optical fiber used for the impact detection optical fiber sensor shown in FIG. It is explanatory drawing which shows the impact detection state of the impact detection optical fiber sensor which is a reference example . FIG. 10A is a cross-sectional view showing a state in which an impact detection optical fiber sensor as a reference example does not receive an impact. FIG. 10B is a cross-sectional view showing a state where the impact detection optical fiber sensor has received an impact. It is a time-dependent change figure which shows the change of the light quantity which passes the impact detection optical fiber sensor which is a reference example , and the sensor of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Impact detection optical fiber sensor system 10 Impact detection optical fiber sensor 10a Sensor part 11 Light emitting element 12 Plastic optical fiber 12a Detection fiber 12i, 12o Plastic optical fiber 13 Light receiving element 14 Electrical signal line 17 Rack member 17a Groove

Claims (11)

  A plastic optical fiber for detecting an impact, a rubber layer covering the outer peripheral part of the plastic optical fiber with a predetermined thickness, and an outer peripheral part of the plastic optical fiber covered with the rubber layer along its longitudinal direction A rack member formed in a bowl shape that is exposed and accommodated; and a convex member that is formed inside the rack member and that deforms the plastic optical fiber accommodated in response to an impact. Impact detection optical fiber sensor.   2. The impact detection light according to claim 1, wherein the rack member is provided along a longitudinal direction of the plastic optical fiber coated with the rubber layer, and is configured to face an exposed portion of the plastic optical fiber in an impact direction. Fiber sensor.   The impact detection optical fiber sensor according to claim 1 or 2, wherein the rack member is formed in a groove having a substantially U-shaped or U-shaped cross section perpendicular to the groove longitudinal direction. The impact detection optical fiber sensor according to any one of claims 1 to 3, wherein the plastic optical fiber is detachable with respect to the groove of the rack member.   The impact detection optical fiber sensor according to any one of claims 1 to 3, wherein the rack member is made of hard plastic, or metal such as stainless steel or brass.   The impact detection optical fiber sensor according to any one of claims 1 to 5, wherein the plastic optical fiber uses a cross-linked acrylic resin as a core material and a fluorine resin that does not transmit moisture as a cladding material.   The impact detection optical fiber sensor according to claim 1, wherein a plurality of the convex members are provided in the longitudinal direction of the groove.   The impact detection optical fiber sensor according to claim 1, wherein the convex member is formed in a semi-cylindrical shape.   The impact detection optical fiber sensor according to claim 1, wherein the rubber layer is formed of ethylene propylene rubber.   The plastic optical fiber is extended from the impact detection optical fiber sensor according to any one of claims 1 to 9, and a light emitting element is connected to one of the plastic optical fibers, and a light receiving element is connected to the other, and the light from the light emitting element is received. The light is incident on the plastic optical fiber, received by a light receiving element, and a change in the amount of the received light is detected to detect distortion of the plastic optical fiber, and the shock detection optical fiber sensor receives the distortion from the distortion. An impact detection optical fiber sensor system for detecting the impact.   The plastic optical fiber is extended from the impact detection optical fiber sensor according to any one of claims 1 to 9, and a light emitting element is connected to one of the plastic optical fibers, and a light receiving element is connected to the other, and the light from the light emitting element is received. Incident into the plastic optical fiber, the light is received by the light receiving element, the change in the amount of the received light is detected, and on the other hand, according to the speed, weight, and stiffness of the measurement object attached with the shock detection optical fiber sensor The light loss pattern is obtained in advance from the change in the amount of light, the light loss pattern detected when subjected to the impact is detected, and the light loss pattern is compared with the previously obtained light loss pattern for speed, weight, and rigidity. An impact detection optical fiber sensor system characterized by identifying

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