Detection sensor and monitoring

Abstract

To reduce the burden of equipping a detection sensor for monitoring such a liquid object as a liquid resin.SOLUTION: The detection sensor includes: a light transmission body group including a plurality of light transmission bodies for transmitting light supplied from a light source; and a holder in the shape of a thin band for supporting the light transmission body group. The holder has a first holder element for supporting one or plural light transmission body groups in a supporting surface spreading in a first direction and in a second direction perpendicular to the first direction. The light transmission bodies are arranged in the second direction.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a sensor for detecting a liquid substance, and more particularly to a liquid substance detection sensor capable of grasping the state of impregnation during an impregnation operation in which a fiber base material is impregnated with a liquid resin under vacuum. [Background technology]

[0002] Fiber-reinforced plastics (FRP), a lightweight and high-strength material, uses glass fiber or carbon fiber as the reinforcing fiber and is widely used as a composite material in aircraft wings, ships, rotor blades of large wind turbines, railway vehicles, structural components in the construction field, and more. One of the molding methods for components made of composite materials is to impregnate a reinforcing fiber substrate placed in a mold with liquid resin before hardening, and then harden the resin after impregnation to produce a molded product of a specified shape. This molding method is called RTM (Resin Transfer Molding). Since a certain strength is required for the FRP components used in the above-mentioned composite materials, it is essential in RTM to reliably impregnate the reinforcing fiber substrate with resin to prevent the occurrence of non-impregnation defects that cause a decrease in strength. Therefore, at sites where FRP components are industrially produced using RTM, it is necessary to detect and monitor whether the resin has spread throughout the entire area of ​​the reinforcing fiber in order to ensure the strength of the FRP components.

[0003] Patent Document 1 discloses a liquid detection sensor for monitoring resin, which is easy to process and has little variation in light response characteristics. Patent Document 1 includes a first optical path that transmits light from a light source, a curved portion (light scattering portion) where the light transmitted through the first optical path is scattered to the outside, and a second optical path that transmits the light that enters through the curved portion to a predetermined position. In the detection sensor of Patent Document 1, the first optical path, the curved portion, and the second optical path are made of a light-transmitting material, and the amount of light scattered to the outside at the curved portion is greater than the amount of light scattered to the outside in the first optical path or the amount of light scattered to the outside in the second optical path. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2007-218653 A Summary of the Invention [Problem to be solved by the invention]

[0005] The present disclosure aims to reduce the burden of installing detection sensors for monitoring liquid substances such as liquid resin. [Means for solving the problem]

[0006] The detection sensor according to the present disclosure includes: a light transmission body group including a plurality of light transmission bodies each transmitting light supplied from a light source; a thin ribbon-shaped holder for supporting the optical transmission body group; The holder includes: a first holder element (21) that supports one or more of the optical transmission body groups on a support surface that extends in a first direction (longitudinal direction L) and a second direction (width direction W) perpendicular to the first direction; The optical transmission bodies are arranged in the second direction.

[0007] The monitoring system according to the present disclosure comprises: a resin impregnation section (80) in which reinforcing fibers (RF) arranged inside the mold are impregnated with liquid resin; a detection unit (90A, 90B) for detecting the impregnated resin in the resin impregnation unit (80); and a control unit (70) that controls the monitoring operation of the impregnating resin. The detection units (90A, 90B) include any one of the detection sensors (1) according to the present disclosure.

[0008] The present disclosure relates to a method for monitoring an impregnation resin, which detects impregnation of a reinforcing fiber (RF) disposed inside a mold with a liquid resin, comprising: Any of the detection sensors (1) according to the present disclosure is laid inside the mold adjacent to the reinforcing fiber (RF). Effect of the Invention

[0009] According to the detection sensor of the present disclosure, the first holder element supports one or more optical transmission body groups on a support surface that extends in a first direction and a second direction perpendicular to the first direction. Therefore, by installing the first holder element only once, multiple detection surfaces can be provided, and therefore the installation burden can be reduced according to the present disclosure. [Brief description of the drawings]

[0010] [Figure 1] FIG. 2 is a plan view showing a liquid detection sensor according to the embodiment. [Diagram 2] 2 is a cross-sectional view taken along line IIA-IIA in FIG. 1 and a cross-sectional view taken along line IIB-IIB in FIG. [Diagram 3] 13A and 13B are diagrams illustrating modified examples of the detection sensor according to the embodiment of the present disclosure. [Figure 4] 13A and 13B are diagrams illustrating another modified example of the detection sensor according to the embodiment of the present disclosure. [Diagram 5] 1A to 1C are diagrams illustrating a detection principle of resin as a liquid material by a detection sensor according to an embodiment of the present disclosure. [Figure 6] 1 is a graph showing the relationship between the refractive index and Fresnel reflectance of a detection target. [Figure 7] 13A and 13B are diagrams illustrating another modified example of the detection sensor according to the embodiment of the present disclosure. [Figure 8] 13A and 13B are diagrams illustrating another modified example of the detection sensor according to the embodiment of the present disclosure. [Figure 9] FIG. 1 shows an overview of the RTM process. [Figure 10] FIG. 13 is a diagram showing resin impregnation using three types of detection sensors. [Figure 11] 1A and 1B are diagrams showing resin impregnation by a detection sensor 1A. [Figure 12] 13 is a diagram showing the state of resin impregnation by a detection sensor 1F. FIG. [Figure 13]11A and 11B are diagrams illustrating differences in resin impregnation due to differences in the shape of the periphery of the detection sensor. [Figure 14] FIG. 1 is a diagram illustrating an example of a monitoring system according to an embodiment. [Figure 15] FIG. 13 is a diagram illustrating another example of a monitoring system according to an embodiment. [Figure 16] FIG. 2 is a diagram showing an example of the structure of a mold (upper mold) in the monitoring system according to the embodiment. [Figure 17] FIG. 17 is a diagram showing the relationship between the mold and the film in FIG. 16. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, embodiments will be described with reference to the accompanying drawings. The following will explain the detection sensors 1 (1A to 1F), and the systems (60A, 60B) and methods for monitoring the detection of liquid resin as a liquid substance during the RTM process using the detection sensors 1. The following will explain each in turn.

[0012] [Detection sensor 1A: see Figs. 1 to 8] The detection sensor 1A includes a plurality of optical fibers 10 and a holder 20 that supports the plurality of optical fibers 10 by sandwiching them from the front and back. In the detection sensor 1A, since the plurality of optical fibers 10 are supported by the holder 20, the plurality of optical fibers 10 can be arranged in a single operation by laying the holder 20 at required locations. The optical fiber 10 is an example of an optical transmission body according to the present disclosure. In addition, in the detection sensor 1A, a longitudinal direction L, a width direction W, a thickness direction T, as well as a front (F) and a rear (R) are defined as shown in Figs. 1 and 2.

[0013] [Optical Fiber 10: Figure 1, Figure 2] The optical fiber 10 has a three-layer structure with a core, an outer clad, and a coating that covers the clad. The refractive index of the core is made higher than that of the clad, so that light is propagated only to the central core as much as possible by total reflection and refraction. In Fig. 1, as an example, eight optical fibers 10A, 10B, 10C, 10D, 10E, 10F, 10G, and 10H are supported by a holder 20 at intervals in the width direction W. When it is necessary to distinguish between the eight optical fibers, they are referred to as optical fibers 10A, 10B, 10C, 10D, 10E, 10F, 10G, and 10H, and when it is not necessary to distinguish between them, they are referred to as optical fiber 10. The optical fibers 10 are arranged at intervals in the width direction W. By providing such intervals, the resin can be detected according to the progress of the impregnation of the liquid resin.

[0014] The optical fibers 10A, 10B, 10C, 10D, 10E, 10F, 10G, and 10H have different lengths supported by the holder 20. That is, the optical fiber 10A is the longest, and the optical fibers 10B, 10C, 10D, 10E, 10F, 10G, and 10H are gradually shorter in this order. Except for this length, the optical fibers 10A, 10B, 10C, 10D, 10E, 10F, 10G, and 10H have the same specifications and constitute a group of optical transmission bodies according to the present disclosure. Each of the optical fibers 10A, 10B, 10C, 10D, 10E, 10F, 10G, and 10H is provided with a connector 25 for connecting to a monitoring system.

[0015] [Holder 20: Figure 1, Figure 2] The holder 20 includes a first holder element 21 that supports the optical fibers 10 from one side, and a plurality of second holder elements 23 that support the optical fibers 10 from the other side. The first holder element 21 is, for example, made of a resin sheet, has a thin ribbon shape, and extends in a longitudinal direction L (first direction) and a width direction W (second direction) perpendicular to the longitudinal direction L. One side of the first holder element 21 constitutes the support surface of the present disclosure. Note that, to achieve the purpose of the present disclosure, the first holder element 21 is necessary, and the second holder element 23 is a preferred element in the present disclosure.

[0016] Each of the second holder elements 23 is made of, for example, a resin adhesive tape. The first holder element 21 has a larger surface area than the second holder element 23 and supports most of the optical fibers 10. The second holder elements 23 are attached to the first holder element 21 together with the optical fibers 10 at intervals in the longitudinal direction L. The second holder elements 23 are attached to the first holder element 21 at intervals, and the first holder element 21 is open to the outside between the adjacent second holder elements 23 and the second holder element 23. The end face of the optical fiber 10 is disposed in the open portion where the second holder element 23 is not attached. The end face of the optical fiber 10 exposed to the outside becomes the detection surface DF of the resin impregnated during the RTM process. This detection surface DF forms a cleavage surface, and the detection surfaces DF consisting of the cleavage surfaces of the optical fibers 10 are provided at positions shifted in the longitudinal direction L.

[0017] The second holder element 23 is not limited to the above example, and may be provided in one or more regions in the longitudinal direction L of the first holder element 21, and may be provided over a part of the region in the width direction W or over the entire region.

[0018] As described above, the detection sensor 1A has the detection surfaces DF of the optical fibers 10 arranged at multiple positions shifted in the longitudinal direction L. Therefore, for example, the progress of resin impregnation can be detected at multiple positions in order, for example, by detecting that the resin has impregnated up to the optical fiber 10A, then detecting that the resin has impregnated up to the optical fiber 10B, and further detecting that the resin has impregnated up to the optical fiber 10C. Note that, although an example in which the detection surfaces DF are shifted in the longitudinal direction L in the order in which they are arranged from one side to the other in the width direction W has been shown here, the shifting in the positions is not limited to this order.

[0019] Since resin can be detected when the liquid resin reaches the detection surface DF at the tip of each optical fiber 10, the portions other than the tip do not necessarily need to be exposed to the outside. 1 shows an example in which a gap is provided between adjacent optical fibers 10, 10 in the width direction W to make the presence of the optical fibers 10 clear, but as shown by IIB-IIB in Fig. 2, the optical fibers 10 may be in contact with each other without providing a gap in the width direction W. When such a gap exists, it is possible to close the gap. Furthermore, as described later, the second holder element 23 can be attached to both sides of the first holder element 21 in the width direction W along the longitudinal direction L. In this way, the periphery of the detection surface DF of the optical fiber 10 is surrounded by the second holder element 23.

[0020] According to the above-described detection sensor 1A, a plurality of optical fibers 10 are supported by the first holder element 21 of the holder 20. Therefore, by laying the first holder element only once, a plurality of detection surfaces can be provided, and therefore, according to the detection sensor 1A, the burden of installation can be reduced.

[0021] [Detection sensor 1B: see Figure 3] The detection sensor 1A has been shown as an example in which only a plurality (N) of detection surfaces DF are provided in the longitudinal direction L. This is called a one-dimensional array type sensor, but a two-dimensional array type detection sensor 1B is provided in which a plurality (M) of detection surfaces DF are provided in the width direction W in addition to the plurality (N) in the longitudinal direction L.

[0022] The detection sensor 1B includes three (M=3) sensor units 11B, 12B, and 13B in a one-dimensional array format. The sensor units 11B, 12B, and 13B, each including N optical fibers 10, are spaced apart in the width direction W. Therefore, the detection sensor 1B constitutes a two-dimensional array sensor having detection points, the number of which is represented by N×M. Note that although the illustration of the second holder element 23 and the like is omitted in FIG. 3, the first holder element 21 can be covered with the second holder element 23 so that only the detection surface DF is exposed to the outside. According to the detection sensor 1B, more detection surfaces DF can be provided in one installation operation.

[0023] [Detection sensor 1C: Figure 4] The detection sensor 1A and the detection sensor 1B are examples in which the optical fiber 10 supported by the holder 20 extends straight in the longitudinal direction L, but the present disclosure is not limited to this, and the optical fiber 10 may include a portion that curves from the longitudinal direction L to the width direction W. This example is shown as a detection sensor 1C.

[0024] The detection sensor 1C includes N optical fibers 10, a first portion 11 extending in a longitudinal direction L, and a second portion 13 extending in a width direction W, and the first portion 11 and the second portion 13 are connected by an arc-shaped third portion 15. The detection surfaces DF of the N optical fibers 10 of the detection sensor 1C are, for example, spaced apart in the longitudinal direction L and provided at the same position in the width direction W.

[0025] [Measurement principle and detection sensitivity: see Figures 5 and 6] Next, the detection principle and detection sensitivity of the detection sensor 1 for detecting liquid resin will be described. This detection is based on Fresnel reflection. When light is incident on the boundary surface where materials with different refractive indexes are in contact, part of the light is reflected, which is called Fresnel reflection. The magnitude of reflection depends on the difference in refractive index and the angle of incidence, but the amount of Fresnel reflected light is considered to be almost perpendicular incidence and is calculated by the formula shown in Figure 5. In the case of the detection sensor 1, a difference occurs in the amount of reflected light before and after the resin Re reaches the detection surface DF, which is the end face of the optical fiber 10. In other words, as shown in the graph in Figure 5, the amount of reflected light after the resin Re reaches the detection surface DF is smaller than the amount of reflected light when the air is in contact with the detection surface DF before the resin Re reaches it, and a difference ΔR occurs.

[0026] The relationship between the refractive index (n2) of the material 2 in contact with the detection surface DF of the optical fiber 10 and the Fresnel reflectance R is shown in Figure 6. When the material 2 is air, the Fresnel reflectance is -14.6 dB, and when the material 2 is a specific resin, the Fresnel reflectance is -31.4 dB, and it was confirmed that the difference ΔR in R between air and resin is -16.8 dB. The larger ΔR is, the better the detection sensitivity of the material 2 is, so it is preferable that the core of the optical fiber 10 has a refractive index close to that of the resin Re to be detected.

[0027] [Detection sensors 1D, 5: Fig. 7, Fig. 8] Next, the detection sensors 1D and 1E will be described. The detection sensors 1D and 1E use a ribbon-shaped optical waveguide structure. This optical waveguide structure is a structure in which a material with a large refractive index is sandwiched between materials with a smaller refractive index, providing a path for light to propagate by total reflection. An optical waveguide is one form of optical transmission medium, but a ribbon-shaped or plate-shaped structure is often referred to as an optical waveguide structure.

[0028] The detection sensor 1D made of an optical waveguide includes a plurality of cores 41 having a relatively large refractive index, and a clad 43 having a relatively small refractive index surrounding the cores 41. The cores 41 are spaced apart in the width direction W and extend in the longitudinal direction L. As is known to those skilled in the art, the optical waveguide allows the wiring pitch between the cores 41 to be 60 μm or less, particularly about 10 μm, and can realize a thin sensor structure with high-density optical wiring compared to the detection sensors 1A to 1C using the optical fiber 10. The detection sensor 1D shown in the figure is flat, but since the material constituting the cores 41 and the clad 43 is flexible, it easily bends when a load is applied.

[0029] The detection sensor 1D is provided with a resin introduction path 45 so that the resin Re can be introduced into each of the cores 41 and reach the detection surface DF, which is the end surface of the core 41. The resin introduction path 45 is a gap that penetrates the clad 43 and the core 41 in order from one of the front and back surfaces (front surface) of the detection sensor 1D. The resin introduction path 45 is provided for each of the cores 41, and is provided with a shifted position in the longitudinal direction L. The resin introduction path 45 has a rectangular opening shape in a plan view, and is parallel to the thickness direction T, that is, is in contact with the detection surface DF of the core 41 perpendicularly. When the impregnated resin reaches the portion where the detection sensor 1D is disposed, the resin Re penetrates into the resin introduction path 45 and comes into contact with the core 41. Then, the probe light PL is reflected at the interface between the detection surface DF of the core 41 and the resin Re, and the impregnation of the resin Re can be detected by detecting this reflected light RL.

[0030] The detection sensor 1D shown in Fig. 7 is a one-dimensional array type sensor, but can also be a two-dimensional array type sensor like the detection sensor 1B. Also, in the detection sensor 1D shown in Fig. 7, the core 41 is straight in the longitudinal direction L, but can also be provided with a curved portion like the detection sensor 1C. The same is true for the detection sensor 1E shown in Fig. 8.

[0031] The detection sensor 1E shown in FIG. 8 has the same basic configuration as the detection sensor 1D, but the detection surface DF is inclined in the thickness direction T. As an example, this inclined detection surface DF is provided with a reflection chamber 47 consisting of a triangular gap in side view that penetrates from the clad 43 on one side to the clad 43 on the other side in the thickness direction T. The probe light PL that has traveled through the core 41 from the rear (R) to the front (F) turns 90 degrees at the boundary between the detection surface DF and the reflection chamber 47 and travels forward. If it is assumed that the resin Re reaches directly above the reflection chamber 47, the probe light PL that turns and travels forward is reflected by this resin Re, travels in the opposite direction, turns 90 degrees at the boundary between the detection surface DF and the reflection chamber 47, and is reflected backward (R). The reflection chamber 47 is shielded from the outside by a shielding plate 49.

[0032] According to the detection sensors 1D and 1E, by providing an optical waveguide structure in a film or sheet and incorporating multiple detection surfaces DF, it is possible to mount multiple detection surfaces DF in a single sheet installation operation, and also to reduce the dimension in the thickness direction T compared to the detection sensors 1A to 1C. This reduces the effect of transferring the surface shape of the detection sensor to the reinforcing fibers. In the RTM process, the detection sensor is attached to the surface of the reinforcing fiber and heated and molded through a mold, and then the resin-impregnated part is removed from the mold. The shape of the detection sensor is then transferred to the surface of the reinforcing fiber as unevenness. The detection sensor is required to be as thin as possible so that the transferred unevenness does not exceed the quality tolerance, and the detection sensors 1D and 1E are suitable for meeting this requirement.

[0033] [Method of detecting impregnated resin: see Figures 9 and 10] Next, a method for detecting resin impregnation while regulating the resin flow path will be described. This method is a countermeasure against erroneous detection of resin impregnation due to racetracking that may occur in the RTM process. Here, racetracking occurs as a result of small gaps that inevitably occur in the RTM process. In the case of this embodiment, these gaps occur around the detection sensor 1, and the resin Re in a liquid state flows preferentially through these gaps, which can cause racetracking.

[0034] [RTM process overview] First, an outline of a method for detecting an RTM process will be described with reference to FIG. The reinforcing fiber RF is accommodated between a pair of upper and lower dies 51 and 53. The detection sensor 1 is, for example, sandwiched between the reinforcing fiber RF and the upper die 51. Note that, although both ends in the X direction of the upper die 51 and the lower die 53 are open in Fig. 9, in the actual RTM process, the upper die 51 and the lower die 53 also cover both ends. The upper die 51 and the lower die 53, including this portion, are collectively referred to as the die 50.

[0035] A resin tank 55 for storing liquid resin Re to be impregnated into the interior of the mold 50 and a pump 57 for depressurizing and suctioning the interior of the mold 50 are provided attached to the mold 50. When the resin Re is to be impregnated into the reinforcing fiber RF, the pump 57 is driven to depressurize the interior of the mold 50, thereby suctioning the resin Re in the resin tank 55 into the interior of the mold 50. The suctioned resin Re permeates the interior of the mold 50 from the lower left to the upper right in the figure. In addition, in the mold 50, the X direction, Y direction, and Z direction are defined as shown in FIG. 9 and the like. Also, in FIG. 9, it is shown that the part shown in gray in the reinforcing fiber RF is impregnated with the resin Re.

[0036] [Detection sensors to be compared] Now, three types of detection sensors shown in FIG. 10 are prepared. The three types are, from the left in the figure, detection sensor 1, detection sensor 1A, and detection sensor 1F. The detection sensor 1 does not include the second holder element 23, and the periphery of the detection surface DF on the tip side of the optical fiber 10 is open, and a flow path is formed in all directions of the X direction, Y direction, and Z direction for the resin Re that reaches it. Therefore, the detection sensor 1 is denoted as XYZ-FP. Note that even with a detection sensor 1 that does not include the second holder element 23, it is possible to obtain the basic effect of the present disclosure that multiple detection surfaces DF can be provided in a single installation operation. In the detection sensor 1A, since a plurality of second holder elements 23 are intermittently provided in the longitudinal direction L, a flow path of the resin Re is not formed in the Y direction, and flow paths are provided only in the X and Z directions. Therefore, the detection sensor 1A is denoted as XZ-FP. In the detection sensor 1F, in addition to the multiple second holder elements 23 intermittently provided in the longitudinal direction L, second holder elements 23 are also provided on both sides in the width direction W. Therefore, each detection surface DF of the optical fiber 10 is arranged in a rectangular area surrounded by the rectangular second holder elements 23. When the resin Re reaches this rectangular area, the flow paths in the X and Y directions flowing to other rectangular areas are restricted, and the resin Re flows in the Z direction flow path of the area. Therefore, the detection sensor 1F is denoted as Z-FP.

[0037] [Resin Re flow] <Detection sensor 1> Assume that the detection sensor 1 is impregnated with resin Re in a liquid state as shown in Fig. 10. Even if the resin Re only directly reaches two optical fibers, 10C and 10D, the resin Re that reaches the optical fibers 10C and 10D may travel around the optical fibers 10C and 10D in the Y direction and reach the other optical fibers 10A, 10B, 10E, 10F, etc. Therefore, there is a risk of erroneous detection of resin Re at the points marked with an x ​​in Fig. 10. The points marked with an o in Fig. 10 indicate that resin Re is properly detected.

[0038] <Detection sensor 1A> Assume that the resin Re is impregnated in the detection sensor 1A up to the same place as the detection sensor 1. In the detection sensor 1A, the second holder elements 23 are provided intermittently in the longitudinal direction L, so that the flow path of the resin Re from the strip-shaped area partitioned by the adjacent second holder elements 23 to the adjacent strip-shaped area is restricted. Therefore, the detection sensor 1A can selectively detect the resin Re in the flow path of the resin Re in the X direction and the Z direction. Note that in FIG. 10, the areas marked with △ indicate that the resin Re may be erroneously detected.

[0039] <Detection sensor 1F> The detection sensor 1F is also impregnated with the resin Re up to the same extent as the detection sensor 1. In the detection sensor 1F, the detection surfaces DF of the optical fibers 10 are disposed in a rectangular region surrounded by the rectangular second holder element 23. Therefore, the detection sensor 1F can selectively detect the resin Re in the flow path of the resin Re in the Z direction.

[0040] With reference to FIG. 11, the detection sensor 1A will be further considered. If the detection sensor 1A is not placed, at the timing when the resin has not yet arrived at the position of the detection sensor 1A, there is a small gap G (see FIG. 13) at the end of the detection sensor 1A in the width direction W, and therefore the resin Re may arrive through the gap as shown in FIG. 11. In this case, if the detection sensor 1A is placed, there is no element in the X direction that hinders the flow of the resin Re, and therefore the resin easily reaches the detection surface DF. As shown in FIG. 11, the thin strip-shaped detection sensor 1A or the like may be covered on both sides with one or more sheets Se made of resin or other material for detection.

[0041] 12, in the case of the detection sensor 1F, even if the resin Re reaches through the gap at the end in the width direction W, the resin cannot reach the optical fiber 10 unless it flows in the Z direction once due to the presence of the second holder element 23. In other words, the second holder element 23 provided at the end in the width direction W can delay the arrival of the resin. If the resin Re reaches via the original route during the delay period of the resin Re, correct detection can be achieved without false detection.

[0042] <End face structure of detection sensor: See Figure 13> 13, there is a risk that the resin Re may seep in through a gap G between the detection sensor 1F and the sheets Se, Se covering the detection sensor 1F from the front and back at the ends of the detection sensor in the width direction W. Therefore, it is preferable to adopt a shape of the second holder element 23 that fills this gap G. The gap G has a tapered shape as shown in Fig. 13. Following the shape of this gap G, the second holder element 23 is tapered toward both ends in the width direction W. The tapered shape can be a tapered shape (lower left side of Fig. 13) or a monotonically inclined shape in the thickness direction T (lower right side of Fig. 13).

[0043] [Impregnation monitoring system: Figures 14 and 15] Next, a system for monitoring resin impregnation using the detection sensor 1 according to this embodiment will be described. Two examples, monitoring system 60A and monitoring system 60B, will be described here. Monitoring system 60A uses an optical switch capable of transmitting and receiving probe light PL and signal light SL between multiple optical fibers 10 and switching the optical path. Below, monitoring system 60A will be described first, followed by monitoring system 60B.

[0044] [Monitoring System 60A] The monitoring system 60A includes a control unit 70 that controls the resin impregnation monitoring operation, a resin impregnation unit 80 where the RTM process is performed, and a detection unit 90A that detects resin impregnation in the resin impregnation unit 80 and sends the detection results to the control unit 70.

[0045] The control unit 70 includes a light source 71 that emits the probe light PL, a photodetector 73 that receives the signal light SL, and an optical branching circuit 75 that sends the probe light PL from the light source 71 toward the detection unit 90A and receives the signal light SL from the detection unit 90A and sends it toward the photodetector 73. The control unit 70 includes a signal processing / controller 77 that is connected to both the light source 71 and the photodetector 73 and emits the probe light PL to the light source 71 and receives the signal light SL received by the photodetector 73 to determine impregnation with the resin Re. The control unit 70 also includes a calculation / display unit 79 that acquires the probe light PL and the signal light SL from the signal processing / controller 77, calculates the reflectance difference ΔR before and after the light reaches the resin, and displays the reflectance difference ΔR and the determination result of the resin impregnation.

[0046] The resin impregnation section 80 is equipped with the aforementioned mold 50, resin tank 55, and pump 57, and by driving the pump 57 while the reinforcing fiber RF to be impregnated with the resin Re is supported inside the mold 50, the resin Re is impregnated into the reinforcing fiber RF inside the mold 50.

[0047] The detection unit 90A includes a detection sensor 1 disposed inside the mold 50, and an optical switch 91 that transmits probe light PL to the detection sensor 1 and receives signal light SL from the detection sensor 1. The optical switch 91 continuously switches between a connection between the optical branching circuit 75 and any of the multiple optical fibers 10 of the detection sensor 1. For example, the optical switch 91 switches between the connection between the optical branching circuit 75 and the optical fiber 10A, the connection between the optical branching circuit 75 and the optical fiber 10B, the connection between the optical branching circuit 75 and the optical fiber 10C, and the connection between the optical branching circuit 75 and the optical fiber 10D in sequence. This allows the signal processing / controller 77 to continuously obtain the detection results of the resin Re by each of the optical fibers 10A, 10B, 10C, and 10D.

[0048] 14, the optical fibers 10C and 10D detect the resin Re, but the resin Re has not yet reached the optical fibers 10A and 10B and cannot be detected. Correspondingly, the amount of the signal light SL from the optical fibers 10A and 10B remains the same as before, but the amount of the signal light SL from the optical fibers 10C and 10D decreases. In this way, the monitoring system 60A can detect the degree of impregnation with the resin Re.

[0049] [Monitoring system 60B: Figure 15] The monitoring system 60B has the same configuration as the monitoring system 60A, except that the detection unit 90A of the monitoring system 60A is replaced with a detection unit 90B. The detection unit 90B includes an optical distributor / synthesizer 93 for processing the probe light PL and the signal light SL using multiplexing for transmitting a plurality of signals together on one transmission path, and a detection sensor 1. The detection sensor 1 is the same as that of the detection unit 90A. In the optical distributor / synthesizer 93, a plurality of branch lines 94 connected to the N optical fibers 10 are joined together into one aggregate line 95, which is connected to the optical branching circuit 75 of the control unit 70.

[0050] When the transmission path is an optical fiber, the wavelength division multiplexing (WDM) method is mainly used for multiplexing, so it is preferable to use an optical distributor / combiner 93 that performs WDM. WDM refers to a method in which light of multiple wavelengths is transmitted inside one optical transmission path (optical fiber). In addition to WDM, other multiplexing techniques such as Frequency Division Multiplexing (FDM) and Time Division Multiplexing (TDM) may be adopted.

[0051] [Effects of monitoring systems 60A and 60B] Using the detection sensor 1 according to this embodiment, the optical fibers 10, which are the respective sensor elements, can be automatically switched (60A) or multiple optical fibers 10 can be simultaneously detected (60B), thereby making it possible to grasp the behavior of the change in the resin impregnation distribution over time during the RTM process. This makes it possible to optimally adjust the impregnation conditions of the molded component in the RTM process in-process. Therefore, the monitoring systems 60A and 60B can ensure the quality of the molded component by reducing the risk of non-impregnated areas, and can also improve efficiency by shortening the impregnation process time.

[0052] (Mold structure: see Figures 16 and 17) Next, the structure of a preferred mold 50 used in the RTM process will be described with reference to FIGS. A sensor accommodating chamber 52 in which the detection sensor 1 is disposed is provided in an upper die 51 of a mold 50. The sensor accommodating chamber 52 is recessed upward from the surface of the upper die 51 facing the lower die 53. A dimension T52 of the recess in the sensor accommodating chamber 52 is formed to be approximately the same as the thickness T1 of the detection sensor 1 or slightly smaller than the thickness T1. Moreover, a dimension X52 of the sensor accommodating chamber 52 from the side surface of the detection sensor 1 is preferably set to 10 mm or less.

[0053] One or more resin sheets Se are interposed between the detection sensor 1 and the upper mold 51. As shown in FIG. 17, the detection sensor 1 is fixed to this sheet Se in advance, and the detection sensor 1 is accommodated in the sensor accommodation chamber 52 together with a part of the sheet Se. The detection sensor 1 can be fixed to the sheet Se by a method such as adhesion, fusion, or adhesive tape. A template is made in advance to specify the position at which the detection sensor 1 is to be fixed, and the detection sensor 1 is fixed to a predetermined position on the sheet Se according to the template. FIG. 17 shows an example in which three (M=3) detection sensors 1 are fixed to the sheet Se. In order to place the sheet Se to which the detection sensor 1 is fixed at a predetermined position on the upper die 51, it is preferable to display marks 56, 58 at corresponding positions on the upper die 51 and the sheet Se. The sheet Se is aligned with the upper die 51 by using the marks 56, 58 as targets.

[0054] By providing the sensor accommodating chamber 52, the amount by which the detection sensor 1 protrudes from the upper die 51 toward the reinforcing fiber RF below can be reduced, so the degree to which the shape of the detection sensor 1 is transferred to the molded member can be reduced. Note that by making the depth of the sensor accommodating chamber 52 shallow within a range in which depression and wrinkles of the FRP occurring near the transfer portion are allowed, the processing cost of the upper die 51 can be reduced. By aligning the sheet Se with the upper die 51 using the mark 56 as a guide, the detection sensor 1 can be easily accommodated in the sensor accommodating chamber 52. By making the dimension in the width direction W of the sensor accommodating chamber 52 larger than the dimension in the width direction W of the detection sensor 1, the operation of accommodating the detection sensor 1 in the sensor accommodating chamber 52 can be facilitated.

[0055] [Additional Notes] The present disclosure can be interpreted as follows. [Appendix 1] A light transmission body group (10) including a plurality of light transmission bodies (10) each transmitting light supplied from a light source; A thin ribbon-shaped holder (20) for supporting a group of optical transmission bodies, The holder (20) is The optical fiber optics device includes a first holder element (21) that supports one or more optical transmission body groups (10) on a support surface extending in a first direction (longitudinal direction L) and a second direction (width direction W) perpendicular to the first direction, A liquid detection sensor (1), wherein a plurality of optical transmission bodies (10) are arranged in a second direction.

[0056] [Appendix 2] In addition, in the above-mentioned embodiment, the optical transmission bodies (10) are preferably arranged at intervals in the second direction.

[0057] [Appendix 3] In addition 1 or addition 2, preferably, each of the plurality of optical transmission bodies (10) has a liquid detection surface (DF), The detection faces (DF) of the plurality of optical transmission bodies (10) are offset in position in the first direction.

[0058] [Appendix 4] In any one of Supplementary Note 1 to Supplementary Note 3, preferably, The detection faces (DF) of the plurality of optical transmission bodies (10) are shifted in position in the first direction in the order in which they are arranged in the second direction.

[0059] [Appendix 5] In any one of Supplementary Note 1 to Supplementary Note 4, preferably Each of the plurality of optical transmission bodies (10) is extend straight in a first direction, or It includes a portion that curves from a first direction to a second direction.

[0060] [Appendix 6] In any one of Supplementary Note 1 to Supplementary Note 4, preferably The holder (20) is A second holder element (23) is provided for fixing the optical transmission body (10) to the first holder element (21).

[0061] [Appendix 7] In Appendix 6, preferably, The second holder element (23) is The first holder element (21) is provided in one or more regions in the first direction, and over a part of the region or the entire region in the second direction.

[0062] [Appendix 8] In addition 6 or addition 7, preferably The second holder element (23) is The first holder element (21) is provided at both ends in the second direction along the first direction.

[0063] [Appendix 9] a resin impregnation section (80) in which reinforcing fibers (RF) arranged inside the mold are impregnated with liquid resin; a detection unit (90A, 90B) for detecting the impregnated resin in the resin-impregnated unit (80); A control unit (70) for controlling the monitoring operation of the impregnating resin, The detection unit (90A, 90B) is an impregnated resin monitoring system (60A, 60B) equipped with a detection sensor (1) according to any one of [Appendix 1] to [Appendix 8].

[0064] [Appendix 10] A method for monitoring an impregnation resin, which detects impregnation of a reinforcing fiber (RF) disposed inside a mold with a liquid resin, comprising: A detection sensor (1) according to any one of [Appendix 1] to [Appendix 8] is installed inside a mold adjacent to the reinforcing fiber (RF); A method for monitoring liquids.

[0065] In addition to the above, it is possible to select and discard the configurations given in the above embodiment, or to change them to other configurations as appropriate. For example, the optical fiber 10 is supported by the first holder element 21 by providing the second holder element 23, but the optical fiber 10 can also be supported by the first holder element 21 by, for example, bonding the optical fiber 10 to the first holder element 21. In other words, the embodiment of supporting the optical fiber 10 on the first holder element 21 is arbitrary. [Explanation of symbols]

[0066] 1, 1A, 1B, 1C, 1D, 1E, 1F Detection sensor 2 substances 11B, 12B, 13B Sensor unit 10,10A,10B,10C,10D,10E,10F,10G,10H Optical fiber 11 Part 1 13 Part 2 15 Part 3 20 Holder 21 First holder element 23 Second holder element 41 cores 43 Clad 45 Resin introduction path 47 Reflection chamber 49 Shield plate 50 Mold 51 Upper mold 52 Sensor Containment Room 53 Lower mold 55 Resin tank 56 Landmark 57 Pump 60A, 60B Monitoring System 70 Control section 71 Light source 73 Photodetector 75 Optical branch circuit 77 Controller 79 Display section 80 Resin impregnated part 90A, 90B Detection section 91 Optical Switch 93 Light splitter / combiner 94 Branch Line 95 Assembly Line DF detection surface L Longitudinal RF reinforced fiber PL probe light RL reflected light Re resin SL signal light T thickness direction W Width direction

Claims

1. a light transmission body group including a plurality of light transmission bodies each transmitting light supplied from a light source; a thin ribbon-shaped holder for supporting the optical transmission body group; The holder includes: a first holder element that supports one or more of the optical transmission bodies on a support surface that extends in a first direction and a second direction perpendicular to the first direction; The optical transmission bodies are arranged in the second direction. Liquid detection sensor.

2. The optical transmission bodies are arranged at intervals in the second direction. The detection sensor according to claim 1 .

3. Each of the plurality of optical transmission bodies has a detection surface for detecting the liquid, The detection surfaces of the plurality of optical transmission bodies are offset in position in the first direction. The detection sensor according to claim 1 .

4. The detection surfaces of the plurality of optical transmission bodies are shifted in position in the first direction in the order in which they are arranged in the second direction. The detection sensor according to claim 3.

5. Each of the plurality of optical transmission bodies is extend straight in the first direction, or a portion curved from the first direction to the second direction; The detection sensor according to claim 1 .

6. The holder includes: a second holder element for fixing the optical transmission body to the first holder element; The detection sensor according to claim 1 .

7. The second holder element comprises: One or more regions in the first direction of the first holder element are provided over a part or all of the region in the second direction; The detection sensor according to claim 6.

8. The second holder element comprises: The first holder element is provided at both ends in the second direction along the first direction. The detection sensor according to claim 6.

9. a resin impregnation section in which reinforcing fibers disposed inside the mold are impregnated with liquid resin; A detection unit that detects the impregnated resin in the resin impregnation unit; A control unit that controls a monitoring operation of the impregnated resin, The detection unit includes the detection sensor according to any one of claims 1 to 8. An impregnating resin monitoring system.

10. A method for monitoring an impregnation resin, which detects impregnation of a reinforcing fiber disposed inside a mold with a liquid resin, comprising: The detection sensor according to any one of claims 1 to 8 is installed inside the mold and adjacent to the reinforcing fibers. A method for monitoring liquids.

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