JP4568145B2 - Shock detecting optical fiber sensor, load concentrating plate and manufacturing method thereof - Google Patents

Description

  The present invention relates to an impact detection optical fiber sensor for detecting an impact, and more particularly to a load concentrating plate for applying an impact load to an optical fiber for detecting an impact and a method for manufacturing the same.

  The impact detection optical fiber 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.

  For example, as shown in FIG. 10, the impact detection optical fiber sensor 50 includes an optical fiber 51 for detecting an impact, a light emitting element (not shown) connected to one end of the optical fiber 51, and the optical fiber 51. A light receiving element (not shown) connected to the other end, and a load concentrating plate 52 provided along the longitudinal direction of the optical fiber 51 are provided. The optical fiber 51 and the load concentrating plate 52 are molded and integrated with a molding material 53, and the optical fiber 51, the load concentrating plate 52 and the molding material 53 constitute a sensor unit 54 of the sensor 50.

  A plurality of protrusions 55 are formed on one side of the load concentrating plate 52 (upper side in FIG. 10A) at predetermined intervals in the longitudinal direction so as to apply an impact load to the optical fiber 51. The heights of the protrusions 55 are all equal, and the optical fiber 51 and the protrusions 55 are in contact with each other. In general, the protrusion 55 is formed in an R shape.

  When an impact load is applied to the sensor portion 54 of the sensor 50 due to a collision with another vehicle or an obstacle, the optical fiber 51 is pressed against the projection 55 side of the load concentration plate 52 and bent. Then, a bending loss corresponding to the impact is generated in the optical fiber 51, so that the presence or absence and the magnitude of the impact can be detected from the loss amount. The amount of loss of the optical fiber 51 can be measured by observing a change in the amount of light transmitted through the optical fiber 51.

JP-T-2002-531812

  By the way, conventionally, when manufacturing the load concentration plate 52 having a plurality of projections 55, a ribbon-like plate having a thickness sufficient to form the projections 55 is cut into a mountain shape by submerged wire discharge or the like. Was.

  However, since it is necessary to perform the submerged wire discharge in the water tank, the length of the load concentration plate 52 that can be manufactured is limited depending on the size of the water tank (generally, the maximum length is 50 cm). Less than). Therefore, when manufacturing a long load concentration plate 52 that cannot be put in the water tank, a plurality of short load concentration plates 52 are formed by submerged wire discharge and connected in the longitudinal direction by welding or the like. It was. In this case, it is necessary to add a step of connecting a plurality of short load concentrating plates 52, and there is a problem that the manufacturing cost increases. Further, there is a problem that the positional accuracy between the load concentration plates 52 when connecting a plurality of short load concentration plates 52 is low, and it is difficult to manufacture the long load concentration plates 52 with high dimensional accuracy.

  Therefore, an object of the present invention is to provide a load concentrating plate that can be manufactured at a low cost and with high dimensional accuracy even for a long load concentrating plate, a manufacturing method thereof, and an impact detection optical fiber sensor including the same. It is to provide.

In order to achieve the above object, an invention according to claim 1 is directed to 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. And a load concentrating plate provided along the optical fiber and formed with a plurality of protrusions along the longitudinal direction so as to apply an impact load to the optical fiber. The plate includes a plurality of holes formed at predetermined intervals with a punch for punching in the longitudinal direction of the ribbon-like plate, and connection portions formed between the holes, and at both ends in the longitudinal direction of the connection portion. The impact detection optical fiber sensor is characterized in that an upper surface is formed into a curved surface by a press , and a connecting portion thereof forms the protrusion.

  The invention according to claim 2 is the impact detection optical fiber sensor according to claim 1, wherein both end portions in the longitudinal direction of the connecting portion are formed in a dovetail shape in a plan view or a quadrangular shape in a plan view.

According to a third aspect of the present invention, there is provided a load concentration plate provided along an optical fiber, wherein a plurality of protrusions are formed along the longitudinal direction so as to apply an impact load to the optical fiber. A plurality of holes formed at predetermined intervals with a punch for punching, and a connection portion formed between the holes, the upper surface of both ends in the longitudinal direction of the connection portion is formed into a curved shape by a press , The load concentrating plate is characterized in that the connecting portion forms the protrusion.

  The invention according to claim 4 is the load concentrating plate according to claim 3, wherein both ends in the longitudinal direction of the connecting portion are formed in a dovetail shape in a plan view or a quadrangular shape in a plan view.

  According to a fifth aspect of the present invention, there is provided a method for manufacturing a load concentration plate provided along an optical fiber, wherein a plurality of protrusions are formed along the longitudinal direction so as to apply an impact load to the optical fiber. Forming a plurality of holes at a predetermined interval in the longitudinal direction, processing both ends in the longitudinal direction of the connecting portion formed between the holes into a curved surface by pressing, and forming the connecting portion as the protrusion It is the manufacturing method of the load concentration board characterized.

  According to a sixth aspect of the present invention, the plurality of holes are substantially I-shaped, and the connecting portion formed between the substantially I-shaped holes has protrusions at both longitudinal ends thereof, and the protrusions 6. A method for producing a load concentrating plate according to claim 5, wherein the upper surface of the substrate is processed into a curved surface by a press.

  A seventh aspect of the present invention is the method for manufacturing a load concentrating plate according to the sixth aspect of the present invention, wherein the projecting portion is expanded by a curved surface processing punch, and the upper surface thereof is formed into a curved surface shape and formed into a dovetail shape in plan view.

  According to an eighth aspect of the present invention, the plurality of holes have a substantially quadrangular shape, and the upper surfaces of both ends in the longitudinal direction of the connecting portion formed between the substantially quadrangular holes are processed into a curved surface shape by pressing. It is a manufacturing method of the load concentration board of description.

  According to the ninth aspect of the present invention, both end portions in the longitudinal direction of the connecting portion are crushed with a punch for curved surface processing, the ribbon-like plate is spread outward in the width direction, and then both end portions in the width direction of the ribbon-like plate are expanded. It is a manufacturing method of the load concentration board of Claim 8 cut | disconnected in linear form.

  According to this invention, even if it is a long load concentration board, there exists an outstanding effect that it can manufacture at low cost and with sufficient dimensional accuracy.

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

  FIG. 1 shows an impact detection optical fiber sensor provided with a load concentrating plate according to a first embodiment of the present invention, (a) is a side sectional view, and (b) is Ib-Ib in FIG. 1 (a). FIG. FIG. 2 shows a load concentrating plate according to the first embodiment, wherein (a) is a side sectional view and (b) is a plan view.

  As shown in FIG. 1, an impact detection optical fiber sensor 10 includes an optical fiber 1 for detecting an impact, a light emitting element (not shown) such as a semiconductor laser connected to one end of the optical fiber 1, an optical fiber, and the like. 1 is provided with a light receiving element (not shown) such as a photodiode connected to the other end of the optical fiber 1 and a load concentrating plate 11 extending along the longitudinal direction of the optical fiber 1. The optical fiber 1 and the load concentration plate 11 are molded and integrated by a molding material 3, and the optical fiber 1, the load concentration plate 11 and the molding material 3 constitute a sensor unit 4 of the sensor 10.

  The optical fiber 1 includes a core 5 having a substantially circular cross section for propagating light, and a clad layer 6 having a substantially circular cross section provided to cover the outer peripheral surface of the core 5. The clad layer 6 is provided concentrically with the core 5.

  As the optical fiber 1, a plastic optical fiber (POF) can be used. In that case, the core 5 of the POF 1 is made of a synthetic resin excellent in heat resistance (for example, acrylic resin, cross-linked acrylic resin (thermosetting acrylic resin), or silicone resin), and the cladding layer 6 of the POF 1 has heat resistance, It consists of a synthetic resin excellent in water resistance and mechanical properties (for example, a fluorine resin such as a fluoroethylenepropylene resin (FEP)).

  The load concentration plate 11 is made of iron (for example, cold rolled steel plate (SPCC-SD)).

  As shown in FIGS. 1 and 2, the load concentrating plate 11 has a plurality of substantially I-shaped holes 13 formed at predetermined intervals in the longitudinal direction of the ribbon-like plate 12 (see FIG. 2B). And a connecting portion 14 formed between the adjacent holes 13. At both ends in the longitudinal direction of the connecting portion 14, protruding portions 15 having an upper surface formed in a curved shape are provided. The protrusion 15 is formed in a dovetail shape in plan view (or a trapezoidal shape in plan view) (see FIG. 2B).

  The upper surface of the central portion in the longitudinal direction of each connection portion 14 is in contact with POF 1. These connecting portions 14 constitute protrusions for applying an impact load to the POF 1.

  Hereinafter, a method of manufacturing the load concentration plate 11 will be described with reference to FIGS.

  Drawing 3 shows the 1st process of the manufacturing method of the load concentration board concerning a first embodiment, (a) is a side sectional view and (b) is a top view. FIG. 4 shows a second step of the method for manufacturing a load concentration plate according to the first embodiment, wherein (a) is a side sectional view and (b) is a plan view.

  First, a plurality of substantially I-shaped holes 13 (see FIG. 4B) are formed by pressing in the ribbon-like plate 12 shown in FIG. 3 at a predetermined interval in the longitudinal direction. The hole forming mold for forming the hole 13 in the plate 12 includes a die (not shown) for installing the plate 12, and a punching punch 21 provided above the die so as to be movable up and down. A pad (not shown) is provided on the side of the punching punch 21 so as to be movable up and down and for pressing the plate 12 onto the die. In the lower end portion of the punch 21 for punching, a press portion 22 formed in a substantially I shape when viewed from below is provided in order to form a substantially I-shaped hole 13 in the plate 12. In FIG. 3, only one punching punch 21 is shown, but a plurality of punching punches 21 may be arranged in the longitudinal direction of the plate 12.

  With the plate 12 placed on the die, the punching punch 21 and the pad are lowered onto the plate 12, the plate is sandwiched between the die and the pad, and the pressing portion 22 of the punching punch 21 is pressed against the plate 12. Thus, a substantially I-shaped hole 13 is formed in the plate 12. Similarly, the holes 13 are sequentially formed over the longitudinal direction of the plate 12. Thereby, as shown in FIG. 4, a connection portion 14 is formed between the adjacent holes 13. In the present embodiment, since the hole 13 is formed in a substantially I shape, protrusions 15 are provided at both ends in the longitudinal direction of each connection part 14, and both sides of the protrusions 15 (in FIG. 4B). In the vertical direction), a material escape portion 23 is formed for releasing the material that has been expanded during the curved surface processing described later.

  Next, the upper surface of the protruding portion 15 of the connecting portion 14 is processed into a curved surface shape by a press. A curved surface processing die for processing the upper surface of the protruding portion 15 into a curved surface has a die (not shown) for installing the plate 12 and a curved surface processing provided so as to be vertically movable above the die. And a pad (not shown) for pressing the plate 12 on the die. In FIG. 4, only one curved surface processing punch 24 is shown, but a plurality of curved surface processing punches 24 may be arranged in the longitudinal direction of the plate 12.

  The width of the curved surface processing punch 24 is formed larger than the width of the protrusion 15. In the present embodiment, the width of the curved surface processing punch 24 is slightly smaller than the width of the hole 13. A press portion 25 is recessed in the lower end portion of the curved surface processing punch 24. The central portion 26 in the longitudinal direction of the press portion 25 is formed in a flat shape, and both longitudinal end portions 27 (left and right end portions in FIG. 4A) of the press portion 25 crush the upper surface of the protruding portion 15 into a curved shape. Therefore, it is formed in an R shape.

  With the plate 12 placed on the die, the curved surface processing punch 24 and the pad are lowered onto the plate 12, the plate is sandwiched between the die and the pad, and the upper surface of the protruding portion 15 of the connecting portion 14 is used for curved surface processing. The longitudinal end portion 27 of the press portion 25 of the punch 24 is pressed. As a result, the protrusion 15 is expanded by the curved surface processing punch 24, and only the upper surface of the protrusion 15 is processed into a curved surface. At that time, since the expanded material escapes to the material escape portion 23, the projecting portion 15 is expanded outward in the width direction to form a dovetail shape in plan view. Similarly, the upper surface of the protruding portion 15 is processed into a curved surface along the longitudinal direction of the plate 12. Thereby, the load concentration board 11 shown in FIG.1 and FIG.2 can be obtained.

  As described above, in the present embodiment, a plurality of substantially I-shaped holes 13 are formed in the ribbon-like plate 12 at a predetermined interval in the longitudinal direction, and the longitudinal direction of the connecting portion 14 formed between the holes 13 is formed. The upper surface of the protruding portion 15 provided at both end portions is processed into a curved surface shape by a press, and the connecting portion 14 is a projection for applying an impact load to the POF 1. The pressing process does not need to be performed in the water tank as in the case of submerged wire discharge, and even a relatively long plate 12 can be processed by appropriately shifting the pressing position. Therefore, according to this embodiment, even if it is a long load concentration plate, it is not necessary to connect a plurality of short load concentration plates in the longitudinal direction by welding or the like. be able to.

  By the way, when the load concentration plate 11 and the like are molded with the molding material 3 in order to manufacture the sensor 10, an extrusion method may be used. In this extrusion method, the load concentration plate 11 is inserted from an insertion port of an extruder (not shown), and the load concentration plate 11 covered with raw rubber (mold material 3) is pushed out to the discharge port side of the extruder. To do.

  When this extrusion method is performed, a core die for controlling the shape of the molding material 3 is provided on the discharge port side of the extruder. Therefore, when performing the extrusion method, it is necessary to reduce a dimensional error (positional deviation) between the load concentration plate 11 and the core plate. Therefore, according to this embodiment, since the load concentration plate 11 can be manufactured with high dimensional accuracy, the sensor 10 with small sensitivity variation and high dimensional accuracy can be manufactured.

  Next, an impact detection optical fiber sensor provided with a load concentration plate according to the second embodiment will be described.

  5A and 5B show an impact detection optical fiber sensor provided with a load concentration plate according to a second embodiment of the present invention, wherein FIG. 5A is a side sectional view, and FIG. 5B is Vb-Vb in FIG. FIG. FIG. 6 shows a load concentration plate according to the second embodiment, where (a) is a side sectional view and (b) is a plan view.

  The impact detection optical fiber sensor 30 shown in FIG. 5 is partially different from the load concentration plate 11 in FIG. Other configurations of the sensor 30 are the same as those of the sensor 10 shown in FIG. Accordingly, the same members are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIGS. 5 and 6, the load concentration plate 31 includes a plurality of substantially rectangular holes 33 (see FIG. 6B) formed at predetermined intervals in the longitudinal direction of the ribbon-like plate 32. , And a connecting portion 34 formed between the adjacent holes 33. At both ends in the longitudinal direction of the connection portion 34, curved surface portions 35 having upper surfaces formed in a curved shape are provided. The curved surface portion 35 is formed in a square shape in plan view (see FIG. 6B).

  The upper surface of the central portion in the longitudinal direction of each connection portion 34 comes into contact with POF 1. These connecting portions 34 constitute protrusions for applying an impact load to the POF 1.

  Hereinafter, a method of manufacturing the load concentration plate 31 will be described with reference to FIGS.

  Drawing 7 shows the 1st process of the manufacturing method of the load concentration board concerning a second embodiment, (a) is a side sectional view and (b) is a top view. FIG. 8: shows the 2nd process of the manufacturing method of the load concentration board which concerns on 2nd embodiment, (a) is side surface sectional drawing, (b) is a top view. FIG. 9 shows a third step of the method for manufacturing the load concentration plate according to the second embodiment, wherein (a) is a side sectional view and (b) is a plan view.

  First, a plurality of substantially square-shaped holes 33 (see FIG. 8B) are formed by pressing in the ribbon-like plate 32 shown in FIG. 7 at predetermined intervals in the longitudinal direction. The hole forming mold for forming the hole 33 in the plate 32 includes a die (not shown) for installing the plate 32, and a punching punch 41 provided above the die so as to be movable up and down. A pad (not shown) is provided on the side of the punch 41 for punching so as to be movable up and down and for pressing the plate 32 onto the die. At the lower end of the punch 41 for punching, in order to form a substantially square hole 33 in the plate 32, a press part 42 formed in a substantially square shape when viewed from below is provided. In FIG. 7, only one punching punch 41 is shown, but a plurality of punching punches 41 may be arranged in the longitudinal direction of the plate 32.

  With the plate 32 placed on the die, the punching punch 41 and the pad are lowered onto the plate 32, the plate 32 is sandwiched between the die and the pad, and the pressing portion 42 of the punching punch 41 is pressed against the plate 32. Thus, a substantially square hole 33 is formed in the plate 41. Similarly, the holes 33 are sequentially formed over the longitudinal direction of the plate 32. As a result, as shown in FIG. 8, a connecting portion 34 is formed between the adjacent holes 33.

  Next, the upper surface of both ends in the longitudinal direction of the connecting portion 34 is processed into a curved surface shape by a press. A curved surface processing die for processing the upper surface of both end portions in the longitudinal direction of the connection portion 34 into a curved surface is freely movable up and down above the die (not shown) for installing the plate 32. A curved surface processing punch 44 is provided, and a pad (not shown) is provided on the side of the curved surface processing punch 44 so as to be movable up and down and press the plate 32 onto the die. In FIG. 8, only one curved surface processing punch 44 is shown, but a plurality of curved surface processing punches 44 may be arranged in the longitudinal direction of the plate 32.

  In the present embodiment, the width of the curved surface processing punch 44 is slightly smaller than the width of the hole 33. A press portion 45 is recessed in the lower end portion of the curved surface processing punch 44. The central part 46 in the longitudinal direction of the press part 45 is formed in a planar shape, and both longitudinal end parts 47 (left and right end parts in FIG. 8A) of the press part 45 are upper surfaces of both longitudinal end parts of the connection part 34. Is formed in an R shape so as to be crushed into a curved surface.

  With the plate 32 placed on the die, the curved surface processing punch 44 and the pad are lowered onto the plate 32, the plate 32 is sandwiched between the die and the pad, and curved surfaces are formed on the upper surfaces of both ends in the longitudinal direction of the connecting portion 34. A longitudinal end portion 47 of the press portion 45 of the processing punch 44 is pressed. As a result, both end portions in the longitudinal direction of the connecting portion 34 are crushed by the curved surface processing punch 44, and only the upper surfaces of both end portions in the longitudinal direction are processed into curved surfaces. Similarly, the upper surfaces of both end portions in the longitudinal direction of the connecting portion 34 are processed into a curved shape over the longitudinal direction of the plate 32.

  As a result, as shown in FIG. 9, a curved surface portion 35 having a rectangular shape in plan view is formed at both ends in the longitudinal direction of the connection portion 34. Further, since the material escape portion 23 (see FIG. 4B) as shown in FIG. 4 does not exist on both sides of the curved surface portion 35, the plate 32 is expanded outward in the width direction, and the ribbon-like plate 32 is formed. Deformed portions 48 are formed at both ends in the width direction.

  Next, both end portions in the width direction of the plate 32 are linearly cut by a press in order to remove the deformed portions 48 formed at both end portions in the width direction of the plate 32. The cutting mold used for cutting both ends in the width direction of the plate 32 includes a die (not shown) for installing the plate 32, and a cutting blade (not shown) provided above the die so as to be movable up and down. And a pad (not shown) for pressing the plate 32 on the die.

  While the plate 32 is placed on the die, the cutting blade and the pad are lowered onto the plate 32, the plate 32 is sandwiched between the die and the pad, and both ends in the width direction of the plate 32 are cut linearly. Thereby, the deformation | transformation part 48 can be removed from the board 32, and the load concentration board 31 shown in FIG.5 and FIG.6 can be obtained.

  As described above, in the present embodiment, a plurality of substantially quadrangular holes 33 are formed in the ribbon-like plate 32 at predetermined intervals in the longitudinal direction, and both longitudinal ends of the connecting portion 34 formed between the holes 33 are formed. The upper surface of the part is processed into a curved surface by a press, and the connecting part 34 is a protrusion for applying an impact load to the POF 1. The pressing process does not need to be performed in the water tank like in-wire wire discharge, and even a relatively long plate 32 can be processed by appropriately shifting the pressing position. Therefore, according to this embodiment, even if it is a long load concentration plate, it is not necessary to connect a plurality of short load concentration plates in the longitudinal direction by welding or the like. be able to.

  Here, the “ribbon-like plate” in the present specification and claims refers to a plate whose overall length is longer than the width, that is, an elongated plate.

  The present invention is not limited to the embodiment described above.

  For example, the material of the load concentration plates 11 and 31 is not limited to the above-described embodiment. For example, hard plastic, brass (BS), stainless steel (SUS), or the like can be used.

  Moreover, the cutting of the both ends in the width direction of the ribbon-shaped plate 32 is not limited to the press working, and may be performed by other means such as a cutting work.

  Furthermore, the cross-sectional shapes of the core 5 and the cladding layer 6 of the optical fiber 1 are not limited to the above-described embodiment. For example, other shapes such as a rectangular cross section and an elliptical cross section may be used.

The impact detection optical fiber sensor provided with the load concentration board which concerns on 1st embodiment of this invention is shown, (a) is side surface sectional drawing, (b) is the Ib-Ib arrow directional cross section of Fig.1 (a). FIG. The load concentration board which concerns on 1st embodiment is shown, (a) is side surface sectional drawing, (b) is a top view. The 1st process of the manufacturing method of the load concentration board which concerns on 1st embodiment is shown, (a) is side surface sectional drawing, (b) is a top view. The 2nd process of the manufacturing method of the load concentration board which concerns on 1st embodiment is shown, (a) is side surface sectional drawing, (b) is a top view. The impact detection optical fiber sensor provided with the load concentration board which concerns on 2nd embodiment of this invention is shown, (a) is side surface sectional drawing, (b) is the Vb-Vb arrow directional cross section of Fig.5 (a). FIG. The load concentration board which concerns on 2nd embodiment is shown, (a) is side sectional drawing, (b) is a top view. The 1st process of the manufacturing method of the load concentration board which concerns on 2nd embodiment is shown, (a) is side sectional drawing, (b) is a top view. The 2nd process of the manufacturing method of the load concentration board which concerns on 2nd embodiment is shown, (a) is side sectional drawing, (b) is a top view. The 3rd process of the manufacturing method of the load concentration board which concerns on 2nd embodiment is shown, (a) is side surface sectional drawing, (b) is a top view. The impact detection optical fiber sensor provided with the conventional load concentration board is shown, (a) is side surface sectional drawing, (b) is Xb-Xb arrow directional cross-sectional view of Fig.10 (a).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical fiber 10, 30 Impact detection optical fiber sensor 11, 31 Load concentration board 12, 32 Board 13, 33 Hole 14, 34 Connection part 15 Protrusion part 24, 44 Curved surface processing punch

Claims (9)

An optical fiber for detecting an impact, a light emitting element connected to one end of the optical fiber, a light receiving element connected to the other end of the optical fiber, and the optical fiber are provided along the optical fiber. In an impact detection optical fiber sensor comprising a load concentration plate formed with a plurality of protrusions along the longitudinal direction to apply an impact load, the load concentration plate is a punch for punching in the longitudinal direction of the ribbon-shaped plate. A plurality of holes formed at a predetermined interval and a connection portion formed between the holes, and the upper surfaces of both end portions in the longitudinal direction of the connection portion are formed into a curved shape by a press , and the connection portion is An impact detection optical fiber sensor characterized in that the projection is formed.   The impact detection optical fiber sensor according to claim 1, wherein both ends in the longitudinal direction of the connection portion are formed in a dovetail shape in a plan view or a quadrangular shape in a plan view. In a load concentrating plate provided along an optical fiber and formed with a plurality of protrusions along the longitudinal direction so as to apply an impact load to the optical fiber , a predetermined interval is provided with a punch for punching in the longitudinal direction of the ribbon-shaped plate. A plurality of holes formed at intervals, and connection portions formed between the holes, and the upper surfaces of both end portions in the longitudinal direction of the connection portions are formed into a curved shape by a press , and the connection portions form the protrusions. A load concentrating plate characterized by   The load concentrating plate according to claim 3, wherein both end portions in the longitudinal direction of the connecting portion are formed in a dovetail shape in plan view or a quadrangular shape in plan view.   In a method of manufacturing a load concentration plate provided along an optical fiber and having a plurality of protrusions formed along the longitudinal direction so as to apply an impact load to the optical fiber, the ribbon-like plate is spaced at a predetermined interval in the longitudinal direction. A load concentrating plate characterized in that a plurality of holes are formed at intervals, both ends in the longitudinal direction of the connecting portion formed between the holes are processed into a curved shape by a press, and the connecting portion is the protrusion. Production method.   The plurality of holes are substantially I-shaped, and the connection part formed between the substantially I-shaped holes has protrusions at both ends in the longitudinal direction, and the upper surface of the protrusions is curved by pressing. The method for producing a load concentrating plate according to claim 5, which is processed into a shape.   7. The method of manufacturing a load concentrating plate according to claim 6, wherein the protruding portion is expanded with a punch for curved surface processing, and the upper surface thereof is formed into a curved surface shape and formed into a dovetail shape in a plan view.   6. The load concentrating plate according to claim 5, wherein the plurality of holes have a substantially quadrangular shape, and upper surfaces of both end portions in the longitudinal direction of the connecting portion formed between the substantially quadrangular holes are processed into a curved shape by a press. Method.   The both ends in the longitudinal direction of the connecting portion are crushed with a punch for curved surface processing, the ribbon-like plate is squeezed outward in the width direction, and then the both ends in the width direction of the ribbon-like plate are cut linearly. 8. A method for producing a load concentrating plate according to 8.

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