JP2007155588A - Impact detection optical fiber sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve linearity of sensitivity of an impact detection optical fiber sensor over a large load range. <P>SOLUTION: This impact detection optical fiber sensor is equipped with a sensor part 2 having an optical fiber 1 for detecting impact, a light emitting element connected to one end of the optical fiber 1, and a light receiving element connected to the other end of the optical fiber 1. The sensor part 2 is constituted by a low-load detection part 21 and a high-load detection part 22, which have different main detection loads from each other. The low-load detection part 21 and the high-load detection part 22 are arranged so that impact may be applied to both the low-load detection part 21 and the high-load detection part 22. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an impact detection optical fiber sensor for detecting an impact.

  The impact detection sensor is provided in a vehicle such as an automobile, and is for detecting (sensing) an impact at the time of collision with another vehicle or an obstacle.

  As an impact detection sensor, an electric sensor that includes a pressure sensor, an acceleration sensor, or a strain gauge and detects an impact by observing changes in pressure, acceleration, or strain measured by the sensors is generally known.

  An optical fiber type that includes an optical fiber made of glass (quartz or the like) or plastic and detects an impact by observing a change in the amount of light transmitted through the optical fiber is generally known.

  This type of optical fiber type impact detection sensor (impact detection optical fiber sensor) is also described in Patent Documents 1 and 2, and the like.

Japanese Examined Patent Publication No. 6-48220 Japanese Patent Laying-Open No. 2005-140752

  By the way, the conventional shock detection optical fiber sensor has the same structure throughout its entire length. As shown in FIG. 9, when the sensor sensitivity is set to the low load side A (high sensitivity), a high load range (for example, The sensitivity in the range from the load a to the load b in FIG. 9 is reduced. On the other hand, when the sensitivity of the sensor is set to the high load side B (low sensitivity), the low load range (for example, the load 0 to the load a in FIG. Sensitivity in the range up to).

  Therefore, the conventional impact detection optical fiber sensor has a problem that linearity of sensitivity (output linearity) cannot be obtained in a wide load range including a low load range and a high load range.

  Accordingly, an object of the present invention is to provide an impact detection optical fiber sensor capable of improving the linearity of sensitivity over a wide load range.

  In order to achieve the above object, the invention of claim 1 is directed to a sensor unit having an optical fiber for detecting an impact, a light emitting element connected to one end of the optical fiber, and connected to the other end of the optical fiber. In the impact detection optical fiber sensor including the received light receiving element, the sensor unit includes a low load detection unit and a high load detection unit having different main detection loads, and the low load detection unit and the high load detection unit The shock detection optical fiber sensor is arranged so that the impact is applied to both the low load detection unit and the high load detection unit.

  The invention according to claim 2 is the shock detecting optical fiber sensor according to claim 1, wherein the optical fiber is arranged in a U-shaped folded shape, and the low-load detector and the high-load detector are respectively arranged in the linear portion of the optical fiber. It is.

  A third aspect of the present invention is the impact detection optical fiber sensor according to the first aspect, wherein the low load detection unit and the high load detection unit are alternately arranged along a longitudinal direction of the optical fiber.

  A fourth aspect of the present invention is the impact detection optical fiber sensor according to the first aspect, wherein a plurality of the optical fibers are arranged in parallel, and the low-load detection unit and the high-load detection unit are arranged on the optical fibers, respectively.

  The invention according to claim 5 further includes a load concentrating plate having a plurality of protrusions provided at predetermined intervals along the longitudinal direction of the optical fiber, and the high load detector has a pitch of the protrusions that is low. 5. The impact detection optical fiber sensor according to claim 1, wherein the impact detection optical fiber sensor is set to be larger than a pitch of the protrusions in the load detection unit.

  The invention of claim 6 further includes a load concentrating plate having a plurality of protrusions provided at predetermined intervals along the longitudinal direction of the optical fiber, and the high load detection unit includes the optical fiber of the protrusions. The impact detection optical fiber sensor according to any one of claims 1 to 5, wherein a length of the abutting flat portion is set to be larger than a length of the flat portion of the protrusion in the low load detection portion.

  The invention according to claim 7 further includes: a load concentration plate having a plurality of protrusions provided at predetermined intervals along the longitudinal direction of the optical fiber; and a mold material that covers the optical fiber and the load concentration plate. The high load detection unit includes a thickness in the load input direction of the mold material set to be greater than a thickness in the load input direction of the mold material in the low load detection unit. This is an impact detection optical fiber sensor.

  The invention according to claim 8 further includes: a load concentration plate having a plurality of protrusions provided at predetermined intervals along the longitudinal direction of the optical fiber; and a mold material that covers the optical fiber and the load concentration plate. The high-load detection unit includes a width in a direction orthogonal to the load input direction of the mold material that is set larger than a width in a direction orthogonal to the load input direction of the mold material in the low-load detection unit. To an impact detection optical fiber sensor according to any one of items 1 to 7.

  The invention according to claim 9 further includes: a load concentration plate having a plurality of protrusions provided at predetermined intervals along the longitudinal direction of the optical fiber; and a mold material that covers the optical fiber and the load concentration plate. The high load detection unit is an impact detection optical fiber sensor according to any one of claims 1 to 8, wherein the hardness of the mold material is set higher than the hardness of the mold material in the low load detection unit.

  According to a tenth aspect of the present invention, the low load detection unit and the high load detection unit are provided in a front part of a bumper reinforcement of a vehicle, and the high load detection unit is disposed above the low load detection unit. 2. The impact detection optical fiber sensor according to 2.

  According to the present invention, there is an excellent effect that the linearity of sensitivity can be improved over a wide load range.

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

  The impact detection optical fiber sensor of the present embodiment is provided in a vehicle such as an automobile, and is for detecting the presence / absence and magnitude of an impact at the time of collision with another vehicle or an obstacle.

  1A and 1B show an impact detection optical fiber sensor according to an embodiment of the present invention, wherein FIG. 1A is a plan view, and FIG. 1B is a cross-sectional view taken along line Ib-Ib in FIG. (C) is a sectional view taken along line Ic-Ic in FIG.

  As shown in FIGS. 1A to 1C, the impact detection optical fiber sensor of the present embodiment is connected to a sensor unit 2 having an optical fiber 1 for detecting an impact and one end of the optical fiber 1. The light emitting device (not shown) such as a semiconductor laser and a light receiving device (not shown) such as a photodiode connected to the other end of the optical fiber 1 are mainly configured. In the present embodiment, the optical fibers 1 are arranged in a U-shaped folded shape, and the sensor portions 2 are respectively formed on the straight portions 3 of the optical fibers 1.

  As shown in FIGS. 1B and 1C, the optical fiber 1 includes a core portion 4 having a substantially circular cross section for propagating light, and a cross section provided by covering the outer periphery of the core portion 4. The clad part 5 has a substantially circular shape. The clad part 5 is provided concentrically with the core part 4.

  As the optical fiber 1, a plastic optical fiber (hereinafter referred to as POF) can be used. In that case, as the core portion 4, a synthetic resin excellent in heat resistance (for example, an acrylic resin, a cross-linked acrylic resin (thermosetting acrylic resin), or a silicone resin) can be used. The clad part 5 is made of a synthetic resin (for example, a fluorine-based resin such as a fluoroethylene propylene resin) having a lower refractive index than that of the core part 4 and excellent in heat resistance, water resistance and mechanical properties. be able to.

  As shown in FIGS. 1A to 1C, the sensor unit 2 includes a load concentration plate (stress concentration plate) 6 provided to extend along the longitudinal direction of the POF 1, a POF 1 and a load concentration. It has the molding material 7 which coat | covers the board 6 and integrates these. The load concentrating plate 6 is formed with a plurality of protrusions 8 provided at predetermined intervals along the longitudinal direction of the POF 1 and supporting the POF 1 so as to support the impact load applied to the POF 1.

  As the load concentration plate 6, a material harder than POF 1 such as iron (for example, cold rolled steel plate), hard plastic, brass, or stainless steel can be used. Further, as the molding material 7, a synthetic resin (for example, silicone rubber) that is softer than the POF 1 and has flexibility can be used.

  The load concentration plate 6 of the present embodiment includes a plate body 9 provided so as to extend along the longitudinal direction of the POF 1, a plurality of holes 10 formed at predetermined intervals in the longitudinal direction of the plate body 9, and And a connecting portion 11 formed between the adjacent holes 10. The connecting portion 11 constitutes the protrusion 8 described above.

  At the center in the longitudinal direction of the connecting portion 11, a planar portion 12 having a planar shape in side view that is in contact with the outer periphery of the POF 1 is formed to hold the POF 1. Further, at both ends in the longitudinal direction of the connecting portion 11, R-shaped portions 13 having an R shape in side view are formed to prevent the POF 1 from being cut when the POF 1 is bent.

  Here, in the impact detection optical fiber sensor of the present embodiment, the sensor unit 2 has a main detection load different from each other, mainly a low load detection unit (high sensitivity unit) 21 for detecting a low load, and mainly It is characterized by comprising a high load detection part (low sensitivity part) 22 for detecting a high load. That is, the high load detection unit 22 is set to be less sensitive than the low load detection unit 21.

  In the present embodiment, one of the sensor units 2 arranged on the straight portion 3 of the POF 1 is a low load detection unit 21 (see the lower side in FIG. 1A, see FIG. 1C), and the other is a high load detection. A portion 22 (see the upper side in FIG. 1A, see FIG. 1B). The low load detector 21 and the high load detector 22 are arranged in parallel with each other. Further, the low load detection unit 21 and the high load detection unit 22 are arranged so that an impact is applied to both the low load detection unit 21 and the high load detection unit 22.

  As shown in FIGS. 1B and 1C, in the present embodiment, the high load detection unit 22 is configured such that the pitch P1 of the projections 8 is larger than the pitch P2 of the projections 8 in the low load detection unit 21. Is set. By setting the pitches P1 and P2 of the protrusions 8 in this way, the bending number of POF1 per unit length in the high load detection unit 22 is less than the bending number of POF1 per unit length in the low load detection unit 21. Thus, the high load detector 22 can be made less sensitive than the low load detector 21.

  That is, the high load detection unit 22 is set so that the interval between the protrusions 8 adjacent to each other in the longitudinal direction of the load concentration plate 6 is larger than the interval between the protrusions 8 in the low load detection unit 21.

  In the present embodiment, the length L1 of the flat surface portion 12 of the protrusion 8 is set to be greater than the length L2 of the flat surface portion 12 of the protrusion 8 in the low load detection portion 21 of the high load detector 22. In this way, by setting the lengths L1 and L2 of the flat surface portion 12 of the protrusion 8, the contact area (contact length) of the protrusion 8 of the high load detector 22 with respect to the POF 1 can be changed to the protrusion of the low load detector 21. 8 is larger than the contact area (contact length) with respect to the POF 1, and the high load detection unit 22 can be made less sensitive than the low load detection unit 21.

  The impact detection optical fiber sensor of this embodiment detects the impact from the front of a vehicle by installing the sensor part 2 (low load detection part 21 and high load detection part 22) in the bumper part of a vehicle front part. be able to. In this embodiment, the low load detection part 21 and the high load detection part 22 are each installed in the up-down direction of the vehicle at predetermined intervals.

  When the impact detection optical fiber sensor of the present embodiment detects an impact caused by a collision with a pedestrian, if the hood is raised or the airbag is inflated outside the hood, a secondary collision (impact on the bumper) Can be reduced to a pedestrian. When the hood is raised, the space with the engine or the like in the hood is widened, so that the impact on the pedestrian during the secondary collision can be reduced.

  However, when an impact due to a collision with a utility pole or the like is detected, it is necessary not to raise the bonnet. This is because the bonnet bites into the driver space and the driver is more likely to be injured. The collision object can be identified by estimating the magnitude of impact at the time of collision.

  Moreover, it becomes possible to prevent the pedestrian from directly colliding with the vehicle by opening the airbag at the hard part of the vehicle body of the wiper or the pillar part.

  Some have a mechanism that reduces the impact on pedestrians during secondary collisions by making the wiper fixing part (support part) movable. It is possible to operate the wiper fixing part only at a limited time.

  In addition to the above, instead of inflating the airbag to the outside of the hood, inflating the airbag to the lower side of the hood (engine room side) also reduces the impact on pedestrians during secondary collisions. Can do. It is easy to store a mechanism for inflating the airbag on the engine room side of the bonnet.

  Next, the operation of this embodiment will be described.

  The optical signal output from the light emitting element is incident on the light receiving element via POF1. The optical signal (transmitted light amount) detected by the light receiving element is transmitted to the signal processing side outside the sensor.

  When an impact load is applied to the sensor unit 2 (low load detection unit 21 and high load detection unit 22) due to a collision with another vehicle or an obstacle, the POF 1 is bent between the protrusions 8 of the load concentration plate 6, It is pressed against the protrusion 8 and compressed. Then, bending loss (microbend loss) or compression loss corresponding to the impact occurs in POF1, and the amount of transmitted light that propagates through POF1 changes according to the bending loss or compression loss.

  In the present embodiment, one optical signal is used, and the optical loss generated in the low load detection unit 21 and the optical loss generated in the high load detection unit 22 are added on the signal processing side.

  On the other hand, when the time has elapsed since the application of the impact, the shape of the POF 1 is restored by the elastic force of the molding material 7, so that the impact detection optical fiber sensor can be used repeatedly.

  Here, in the present embodiment, the sensor unit 2 has different main detection loads, mainly a low load detection unit 21 for detecting a low load, and a high load detection unit for mainly detecting a high load. The load detection range can be expanded because of the configuration of 22 and the linearity of sensitivity is improved in a wide load range including the low load range and the high load range (for example, the range of load 0 to b in FIG. 2). Can do.

  In the present embodiment, the POF 1 is arranged in a U-shaped folded shape, the low load detection unit 21 and the high load detection unit 22 are arranged on the straight line portion 3 of the POF 1, and the low load detection unit 21 and the high load are arranged. Since the detection unit 22 is arranged in parallel with each other, it is possible to efficiently detect from a low load to a high load, and it is possible to more efficiently determine a collision target.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments, and various other embodiments can be adopted.

  For example, as in the other embodiments shown in FIGS. 3A and 3B, the low load detectors 31 and the high load detectors 32 may be alternately arranged along the longitudinal direction of the POF 1. good. In this embodiment, a plurality of protrusions 34 are provided along the longitudinal direction of one load concentrating plate 33, and the pitches P1 and P2 of the protrusions 34 and the lengths L1 and L2 of the flat surface portion 35 are set as appropriate. The load detection unit 31 and the high load detection unit 32 are alternately arranged. In this case, the low load detection unit 31 and the high load detection unit 32 may be alternately arranged at such an interval that an impact is applied to both the low load detection unit 31 and the high load detection unit 32. In FIG. 3A, the positions of the low load detection unit 31 and the high load detection unit 32 of the upper and lower sensor units may be shifted.

  Further, as in the other embodiments shown in FIGS. 4A to 4C, a plurality (two in the illustrated example) of POFs 1 are arranged in parallel, and each of these POFs 1 has a low load detection unit 41 (21). And the high load detection part 42 (22) may be arrange | positioned. In this embodiment, the low load detector 41 and the high load detector 42 are arranged in parallel with each other. In this embodiment, the low load detector 41 and the high load detector 42 use different optical signals, that is, two optical signals. Then, the optical signal to be used is switched on the signal processing side by the load without adding these optical signals.

  In this embodiment, the load concentration plate 43 for the low load detection unit 41 and the load concentration plate 44 for the high load detection unit 42 are formed separately. However, as shown in FIG. It is also possible to integrate the plates 43 and 44 into one load concentration plate 45.

  Further, as in other embodiments shown in FIGS. 6 (a) to 6 (c), the high load detector 62 is connected to the load input direction of the molding material 7 (in FIGS. 6 (b) and 6 (c)). The thickness T1 (in particular, the thickness of the molding material 7 on the upper side of the POF 1 to which an impact is applied) is set to be thicker than the thickness T2 of the molding material 7 in the load input direction in the low load detector 61. May be. In this embodiment, the pitch P3 of the protrusions 63 and the length L3 of the flat surface portion 64 are set to be equal between the low load detection unit 61 and the high load detection unit 62. The illustrated upper surface of the molding material 7 of the low load detection unit 61 and the illustrated upper surface of the molding material 7 of the high load detection unit 62 coincide with each other. Even in this case, the high load detection unit 62 can be made less sensitive than the low load detection unit 61.

  Further, as in the other embodiments shown in FIGS. 7A to 7C, the high load detector 72 is placed in a direction perpendicular to the load input direction of the molding material 7 (up and down in FIG. 7A). The width W1 of the (direction) may be set to be wider than the width W2 in the direction orthogonal to the load input direction of the molding material 7 in the low load detection unit 71. In this embodiment, the low load detection unit 71 and the high load detection unit 72 set the pitch P3 of the protrusion 73 and the length L3 of the flat surface part 74 equal to each other. Even in this case, the high load detection unit 72 can be made less sensitive than the low load detection unit 71.

  Further, as in other embodiments shown in FIGS. 8A to 8C, the high load detection unit 82 is configured such that the hardness of the mold material 7 is higher than the hardness of the mold material 7 in the low load detection unit 81. You may set as follows. In this embodiment, the low load detector 81 and the high load detector 82 set the pitch P3 of the protrusion 83 and the length L3 of the flat portion 84 equal. Even in this case, the high load detection unit 82 can be made less sensitive than the low load detection unit 81.

  Next, an impact detection optical fiber sensor mounted on a vehicle bumper will be described.

  FIG. 10 is a cross-sectional view of a main part of the vehicle bumper equipped with the impact detection optical fiber sensor, and shows the vehicle bumper as viewed from the left side of the vehicle. In FIG. 10, the front side of the vehicle is indicated by an arrow FR, and the upper side of the vehicle is indicated by an arrow UP.

  A vehicle bumper (hereinafter referred to as a bumper) 90 according to the present embodiment extends in the vehicle width direction at a front end portion of the vehicle, and both end portions in the vehicle width direction of the bumper 90 are curved toward the rear of the vehicle.

  As shown in FIG. 10, the bumper 90 is fixed to a resin bumper cover 91 that covers the outside, a bumper absorber 92 made of a foam material as an impact absorbing member, and a pair of left and right side members (not shown) at the front of the vehicle. The bumper reinforcement 93, the shock detection optical fiber sensor having a pair of upper and lower sensor portions 94, 94 disposed between the bumper absorber 92 and the bumper reinforcement 93, and the impact load input to the bumper absorber 92 It is comprised from the load transmission board 95 etc. for transmitting to the parts 94 and 94. FIG.

  The sensor unit 94 positioned above is a high load detection unit 94H, and the sensor unit 94 positioned below is a low load detection unit 94L. As the impact detection optical fiber sensor, the above-described embodiment shown in FIGS. 1, 7, and 8 can be employed.

  In the bumper 90 configured as described above, when a collision object collides with a predetermined part of the bumper cover 91 from the front of the vehicle (front collision), the bumper cover 91 and the bumper absorber 92 are deformed rearward of the vehicle at the collision part, and the load transmission plate Press 95. As a result, the optical fiber 1 is locally deformed (curved) by the protrusions of the load concentration plate 96, and the light in the optical fiber 1 leaks from the optical fiber 1 to the outside. The greater the impact load, the greater the deformation (curvature) of the optical fiber 1 and the greater the amount of light leakage. The impact can be determined based on the optical transmission loss amount of the optical fiber 1.

  When the pedestrian collides with the bumper 90, the pedestrian has a center of gravity above the bumper 90 and is soft, so the upper body of the pedestrian falls over the hood (bonnet). At that time, the pedestrian's leg is deformed into a "<" shape and then flipped up. Further, since the bumper cover 91 is also soft, its front end surface is deformed obliquely. At that time, a large load is applied to the upper part of the bumper reinforcement 93 due to the fall of the upper body of the pedestrian in front of the bumper reinforcement 93.

  Therefore, since the high load detector 94H is arranged at the upper front portion of the bumper reinforcement 93 and the low load detector 94L is arranged at the lower front portion of the bumper reinforcement 93, impact detection having a load detector (sensor unit) having the same structure. Compared to the case where the optical fiber sensor is arranged, even at the same vehicle speed, it is possible to realize an increase in the amount of light transmitted through the optical fiber 1 and an improvement in detection accuracy.

  11 and 12 are enlarged cross-sectional views of a main part of the vehicle bumper on which the impact detection optical fiber sensor is mounted, and show a state in which the vehicle bumper is viewed from the left side of the vehicle as in FIG.

  As the impact detection optical fiber sensor, the above-described embodiment shown in FIG. 6 is adopted.

  In the impact detection optical fiber sensor shown in FIG. 6 described above, the thickness in the load input direction of the molding material 7 is different between the high load detection unit 62 and the low load detection unit 61 positioned above and below. Specifically, the thickness T1 in the load input direction of the molding material 7 in the high load detection unit 62 positioned above is greater than the thickness T2 of the mold material 7 in the load input direction in the low load detection unit 61 positioned below. Also thick. Thus, when mounting the impact detection optical fiber sensor using the mold material 7 having different thicknesses on the bumper 90, the thickness of the mold material 7 is different, so that the impact load is thick as it is. The upper high load detection unit 62 is input before the lower low load detection unit 61.

  Therefore, in the embodiment shown in FIG. 11, the bumper reinforcement 93 has an upper front surface 93 a that is in contact with the upper high load detection unit 62 and a thickness of the molding material 7 that is lower than the lower front surface 93 b that is in contact with the lower low load detection unit 61. The shape is set so as to be shifted rearward by a dimension t1 corresponding to the difference (T1-T2).

  In the embodiment shown in FIG. 12, the load transmitting plate 95 has a thickness in the vehicle front-rear direction of the upper part 95 a that contacts the upper high load detection unit 62 and the lower part 95 b that contacts the lower low load detection unit 61. The thickness t1 is set to be thinner than the thickness in the longitudinal direction of the vehicle, which corresponds to the thickness difference (T1-T2) of the molding material 7.

  As a result, in the embodiment shown in FIGS. 11 and 12, even if the thickness in the load input direction of the molding material 7 is different between the high load detection unit 62 and the low load detection unit 61 positioned above and below, The impact load from the front of the vehicle can be input substantially simultaneously to the high load detection unit 62 and the low load detection unit 61 positioned above and below.

The impact detection optical fiber sensor which concerns on one Embodiment of this invention is shown, (a) is a top view, (b) is Ib-Ib arrow sectional drawing of Fig.1 (a), (c) is It is Ic-Ic line arrow directional cross-sectional view of Fig.1 (a). It is a load-light loss diagram at the time of impact application in the impact detection optical fiber sensor of the present invention. The impact detection optical fiber sensor which concerns on other embodiment is shown, (a) is a top view, (b) is the IIIb-IIIb arrow directional cross-sectional view of Fig.3 (a). The impact detection optical fiber sensor which concerns on other embodiment is shown, (a) is a top view, (b) is IVb-IVb sectional view taken on the line of FIG. 4 (a), (c) is FIG. It is IVc-IVc arrow directional cross-sectional view of (a). It is a top view of the impact detection optical fiber sensor which concerns on other embodiment. The impact detection optical fiber sensor which concerns on other embodiment is shown, (a) is a top view, (b) is VIb-VIb sectional view taken on the line of FIG. 6 (a), (c) is FIG. It is VIc-VIc arrow directional cross-sectional view of (a). The impact detection optical fiber sensor which concerns on other embodiment is shown, (a) is a top view, (b) is VIIb-VIIb arrow sectional drawing of Fig.7 (a), (c) is FIG. It is a VIIc-VIIc arrow directional cross-sectional view of (a). The impact detection optical fiber sensor which concerns on other embodiment is shown, (a) is a top view, (b) is a VIIIb-VIIIb arrow directional cross-sectional view of Fig.8 (a), (c) is FIG.8. It is a VIIIc-VIIIc arrow directional cross-sectional view of (a). It is a load-light loss diagram at the time of impact application in the conventional impact detection optical fiber sensor. It is principal part sectional drawing of the bumper for vehicles carrying an impact detection optical fiber sensor. It is a principal part expanded sectional view of the bumper for vehicles carrying an impact detection optical fiber sensor. It is a principal part expanded sectional view of the bumper for vehicles carrying an impact detection optical fiber sensor.

Explanation of symbols

1 Optical fiber (POF)
2 Sensor part 3 Linear part 6, 33, 43, 44, 45, 96 Load concentrating plate 7 Mold material 8, 34, 63, 73, 83 Protrusion 11, 35, 64, 74, 84 Plane part 21, 31, 41, 61, 71, 81, 94L Low load detector 22, 32, 42, 62, 72, 82, 94H High load detector 93 Bumper reinforcement

Claims (10)

  In an impact detection optical fiber sensor comprising a sensor unit having an optical fiber for detecting an impact, a light emitting element connected to one end of the optical fiber, and a light receiving element connected to the other end of the optical fiber, The sensor unit is composed of a low load detection unit and a high load detection unit having different main detection loads, and the low load detection unit and the high load detection unit are connected to both the low load detection unit and the high load detection unit. An impact detection optical fiber sensor characterized by being arranged so as to be added to a part.   The impact detection optical fiber sensor according to claim 1, wherein the optical fiber is arranged in a U-shaped folded shape, and the low-load detection unit and the high-load detection unit are arranged in a linear portion of the optical fiber, respectively.   The impact detection optical fiber sensor according to claim 1, wherein the low load detection unit and the high load detection unit are alternately arranged along a longitudinal direction of the optical fiber.   The impact detection optical fiber sensor according to claim 1, wherein a plurality of the optical fibers are arranged in parallel, and the low load detection unit and the high load detection unit are arranged on each of the optical fibers.   A load concentrating plate having a plurality of protrusions provided at predetermined intervals along the longitudinal direction of the optical fiber, wherein the high load detection unit has a pitch of the protrusions of the protrusions in the low load detection unit; The impact detection optical fiber sensor according to claim 1, wherein the impact detection optical fiber sensor is set to be larger than the pitch.   A load concentrating plate having a plurality of protrusions provided at predetermined intervals along the longitudinal direction of the optical fiber, wherein the high load detection unit The impact detection optical fiber sensor according to any one of claims 1 to 5, wherein is set to be larger than a length of a flat portion of the protrusion in the low load detection portion.   A load concentrating plate having a plurality of protrusions provided at predetermined intervals along the longitudinal direction of the optical fiber, and a mold material covering the optical fiber and the load concentrating plate, and the high load detecting unit. The impact detection optical fiber sensor according to any one of claims 1 to 6, wherein a thickness of the mold material in a load input direction is set to be thicker than a thickness of the mold material in a load input direction in the low load detection unit.   A load concentrating plate having a plurality of protrusions provided at predetermined intervals along the longitudinal direction of the optical fiber, and a mold material covering the optical fiber and the load concentrating plate, and the high load detecting unit. The width of the direction orthogonal to the load input direction of the mold material is set larger than the width of the direction orthogonal to the load input direction of the mold material in the low load detection unit. Shock detection optical fiber sensor.   A load concentrating plate having a plurality of protrusions provided at predetermined intervals along the longitudinal direction of the optical fiber, and a mold material covering the optical fiber and the load concentrating plate, and the high load detecting unit. 9. The impact detection optical fiber sensor according to claim 1, wherein the hardness of the mold material is set higher than the hardness of the mold material in the low load detection unit.   The impact detection optical fiber according to claim 2, wherein the low load detection unit and the high load detection unit are provided in a bumper reinforcement front portion of a vehicle, and the high load detection unit is disposed above the low load detection unit. Sensor.

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