Patent Publication Number: US-2020282672-A1

Title: Composite material, pultrusion device, and pultrusion method

Description:
TECHNICAL FIELD 
     The present invention relates to a composite material having a reinforced part formed therein, a pultrusion device, and a pultrusion method. 
     BACKGROUND ART 
     In the related art, a plate-shaped structure having a reinforcing part formed therein is known (refer to, for example, PTL 1). In this plate-shaped structure, the reinforcing part has a solid rod-shaped portion having a core material in the interior thereof. The core material is made of a composite material and is formed by winding a prepreg into a rod shape. 
     CITATION LIST 
     Patent Literature 
     [PTL 1] Japanese Unexamined Patent Application Publication No. 2004-352187 
     SUMMARY OF INVENTION 
     Technical Problem 
     However, in the core material of PTL 1, the core material is formed by winding a prepreg into a rod shape, and therefore, although the core material is provided along a longitudinal direction, in reinforcing fibers which are included in the core material, a fiber direction thereof is not provided along the longitudinal direction, and thus the fiber direction of the reinforcing fiber is not in an appropriate direction with respect to a load which is applied in the longitudinal direction. 
     Therefore, the present invention has an object to provide a composite material suitably reinforced against a load, a pultrusion device, and a pultrusion method. 
     Solution to Problem 
     According to an aspect of the present invention, there is provided a composite material including: a reinforced part which is a part reinforced against a load acting in a load direction, in which the reinforced part includes a core part which includes reinforcing fibers in which a fiber direction is oriented along the load direction, and is provided to extend along the load direction, and a covering part formed by covering a periphery of the core part with a fiber sheet. 
     According to this configuration, the fiber direction of each of the reinforcing fibers which are included in the core part can be oriented along the load direction, and therefore, a load which is applied to the reinforced part can be adequately received by the core part. For this reason, the load can be adequately received at the reinforced part, so that a load due to the load can be reduced at parts other than the reinforced part, and thus a plate thickness or the like can be reduced, so that the weight of the entire composite material can be reduced. It is favorable that the fiber direction of the reinforcing fiber which is a main component of the core part is oriented along the load direction, and the core part may include reinforcing fibers having a fiber direction different from the load direction. 
     Further, it is preferable that when in a cross section taken along a plane orthogonal to the load direction, a neutral axis extending in a predetermined direction is set to be a first neutral axis and a neutral axis extending in a direction orthogonal to the first neutral axis is set to be a second neutral axis, the reinforced part is a part farthest from an intersection of the first neutral axis and the second neutral axis. 
     According to this configuration, a part farthest from the intersection is reinforced, whereby it is possible to reinforce a part where stress due to bending moment to the composite material centered on the intersection becomes larger. For this reason, it is possible to more suitably perform reinforcement against a load. 
     Further, it is preferable that the reinforced part is provided in at least one of a tip portion which is a free end and a corner portion which is bent, in a cross section taken along a plane orthogonal to the load direction. 
     According to this configuration, it is possible to more suitably reinforce the tip portion where stress due to bending moment to the composite material becomes larger, or the corner portion where stress due to a load becomes larger. 
     According to another aspect of the present invention, there is provided a pultrusion device for forming a composite material having a reinforced part which is a part reinforced against a load acting in a load direction, while drawing the composite material in a drawing direction, the reinforced part including a core part which includes reinforcing fibers and is provided to extend along the load direction, and a covering part formed by covering a periphery of the core part with a fiber sheet, the pultrusion device including: a molding tool which forms the composite material having the reinforced part, by drawing the reinforcing fibers and the fiber sheet along the drawing direction, in which the molding tool includes a core part guide part for bundling and guiding the reinforcing fibers so as to form the core part, and a covering part guide part for guiding the fiber sheet so as to cover the periphery of the core part. 
     Further, according to still another aspect of the present invention, there is provided a pultrusion method of forming a composite material having a reinforced part which is a part reinforced against a load acting in a load direction, while drawing the composite material in a drawing direction, the reinforced part including a core part which includes reinforcing fibers and is provided to extend along the load direction, and a covering part formed by covering a periphery of the core part with a fiber sheet, the pultrusion method including: a pultrusion step of forming the composite material having the reinforced part, by drawing the reinforcing fibers and the fiber sheet along the drawing direction, in which in the pultrusion step, the periphery of the core part is covered with the fiber sheet while the core part is formed by bundling the reinforcing fibers. 
     According to these configurations, the fiber direction of each of the reinforcing fibers which are included in the core part can be oriented along the load direction, and therefore, a load which is applied to the reinforced part can be adequately received by the core part. For this reason, the load can be adequately received at the reinforced part, so that a load due to the load can be reduced at parts other than the reinforced part, and thus a plate thickness or the like can be reduced, so that the weight of the entire composite material can be reduced. 
     Further, it is preferable that in the pultrusion step, a sheet folding step of folding the fiber sheet so as to cover the periphery of the core part is performed. 
     According to this configuration, by folding the fiber sheet while drawing the fiber sheet, it is possible to easily cover the periphery of the core part with the fiber sheet. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a sectional view schematically showing an example of a composite material according to Embodiment 1. 
         FIG. 2  is a schematic configuration diagram showing an example of a pultrusion device according to Embodiment 1. 
         FIG. 3  is a schematic configuration diagram showing the periphery of a molding tool of the pultrusion device according to Embodiment 1. 
         FIG. 4  is a flowchart relating to a pultrusion method according to Embodiment 1. 
         FIG. 5  is a sectional view schematically showing an example of a composite material according to Embodiment 2. 
         FIG. 6  is a sectional view schematically showing an example of a composite material according to Embodiment 3. 
         FIG. 7  is a sectional view schematically showing an example of a composite material according to Embodiment 4. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, embodiments of the present invention will be described in detail based on the drawings. The present invention is not limited by the embodiments. Further, constituent elements that can be easily replaced by those skilled in the art, or constituent elements that are substantially identical to the constituent elements in the following embodiments are included in the constituent elements in the following embodiments. Further, the constituent elements described below can be appropriately combined, and in a case where there are a plurality of embodiments, it is also possible to combine the respective embodiments. 
     Embodiment 1 
       FIG. 1  is a sectional view schematically showing an example of a composite material according to Embodiment 1.  FIG. 2  is a schematic configuration diagram showing an example of a pultrusion device according to Embodiment 1.  FIG. 3  is a schematic configuration diagram showing the periphery of a molding tool of the pultrusion device according to Embodiment 1.  FIG. 4  is a flowchart relating to a pultrusion method according to Embodiment 1. 
     The composite material according to Embodiment 1 is a pultrusion material  10  pultruded along a longitudinal direction which is an X-axis direction shown in  FIG. 1 , and has a shape extending in the X-axis direction. The pultrusion material  10  is formed in a predetermined shape in a Y-Z plane shown in  FIG. 1 , that is, in a cross section orthogonal to the longitudinal direction. In Embodiment 1, the pultrusion material  10  is formed in an H shape in cross section. However, there is no limitation thereto, and the pultrusion material  10  may be formed in any shape such as an I shape, a T shape, a concave shape, and a cylindrical shape. 
     The pultrusion material  10  includes a plurality of fiber sheets  20 , a gap material  22 , and a core material (a core part)  24 , as shown in  FIG. 1 . Further, in the pultrusion material  10 , a reinforced part  26  which is a part reinforced against a load acting in a load direction is formed. Although details will be described later, the reinforced part  26  is formed of a part of the fiber sheet  20  and the core material  24 . 
     The plurality of fiber sheets  20  are formed in a sheet shape extending in the X-axis direction and are deformed so as to have a predetermined shape (in  FIG. 1 , an H shape) in the Y-Z plane during the pultrusion. The fiber sheet  20  is a composite material which includes reinforcing fibers and thermosetting resin impregnated in the reinforcing fibers. For each of the fiber sheets  20 , for example, a fiber sheet is used in which a plurality of layers of reinforcing fibers oriented in a predetermined fiber direction are laminated and fiber directions in which the fiber directions in the respective layers are set to be different from each other are multi-directional. Here, in Embodiment 1, as the reinforcing fibers, for example, carbon fibers are applied. However, there is no limitation to the carbon fibers, and glass fibers or the like may also be applied. Further, in Embodiment 1, as the thermosetting resin, for example, epoxy resin is applied. However, there is no limitation to the epoxy resin, and other thermosetting resin may also be applied. 
     The gap material  22  is disposed in a gap which is formed by the plurality of fiber sheets  20 . In Embodiment 1, as the gap material  22 , a material obtained by impregnating reinforcing fibers such as carbon fibers with resin and bundling the reinforcing fibers is applied. Tha gap material  22  is not limited thereto, and a material obtained by appropriately combining other reinforcing fibers and the thermosetting resin may also be applied. 
     Next, the reinforced part  26  which is formed in the pultrusion material  10  will be described with reference to  FIG. 1 . The reinforced part  26  is a part reinforced against a load in which a load direction is the longitudinal direction of the pultrusion material  10 . When in the cross section of the pultrusion material  10  shown in  FIG. 1 , a neutral axis extending in a predetermined direction is set to be a first neutral axis I 1  and a neutral axis extending in a direction orthogonal to the first neutral axis I 1  is set to be a second neutral axis  12 , the reinforced part  26  is a part farthest from an intersection P of the first neutral axis I 1  and the second neutral axis  12 . Here, the first neutral axis I 1  is an axis passing through the center of the pultrusion material  10  in a right-left direction of  FIG. 1 , and the second neutral axis  12  is an axis passing through the center of the pultrusion material  10  in an up-down direction of  FIG. 1 . For this reason, the intersection P is a so-called centroid. Specifically, the reinforced part  26  is provided at each of four tip portions which are free ends of the pultrusion material  10  having an H shape. 
     The reinforced part  26  has the core material  24  and a covering part  28  covering the periphery of the core material  24 . The core material  24  is a cylindrical member in which an axial direction thereof is the longitudinal direction of the pultrusion material  10 . The core material  24  is formed by bundling reinforcing fibers such as carbon fibers and impregnating the bundled reinforcing fibers with resin. The fiber direction of each of the reinforcing fibers which are included in the core material  24  is oriented along the longitudinal direction (that is, the load direction). In the core material  24 , it is favorable that the fiber direction of the reinforcing fiber which is a main component of the core material  24  is oriented along the load direction, and the core material  24  may include reinforcing fibers having a fiber direction different from the load direction. 
     The covering part  28  is at least a part of the fiber sheet  20  configuring the pultrusion material  10  and is provided so as to cover the outer peripheral surface of the core material  24 . For this reason, as reinforcing fibers which are included in the covering part  28 , reinforcing fibers in which a fiber direction thereof is oriented along a direction different from the longitudinal direction are included therein. Here, the fiber direction of each of the reinforcing fibers disposed on the inner peripheral surface of the covering part  28 , which is in contact with the outer peripheral surface of the core material  24 , is set to be a direction other than 90° with respect to the fiber direction in the core material  24 . For this reason, the fiber direction of the reinforcing fiber disposed on the outer peripheral surface of the core material  24  and the fiber direction of the reinforcing fiber disposed on the inner peripheral surface of the covering part  28  are not orthogonal to each other, so that a decrease in interlaminar strength of the core material  24  and the covering part  28  is suppressed. 
     Next, a pultrusion device  100  will be described with reference to  FIG. 2 . The pultrusion device  100  is a device for forming the pultrusion material  10  while drawing the pultrusion material  10  in a drawing direction. At this time, the drawing direction is the same direction as the longitudinal direction of the pultrusion material  10  and is the same direction as the load direction of a load which is applied to the pultrusion material  10 . 
     As shown in  FIG. 2 , the pultrusion device  100  includes a plurality of fiber sheet supply units  110 , a plurality of resin pools  112 , a plurality of core material supply units  124 , and a molding tool  140 . In  FIG. 2 , the illustration of a gap material supply unit that supplies the gap material  22  is omitted. 
     The fiber sheet supply unit  110  is for supplying the fiber sheet  20  toward the molding tool  140 . The fiber sheet supply unit  110  feeds out the fiber sheet  20  in a wound dry state (that is, a state where the fiber sheet  20  is not impregnated with the thermosetting resin). Here, the fiber sheet supply unit  110  is appropriately installed by the number of fiber sheets  20  which are used for the pultrusion material  10  to be formed. However, as the fiber sheet  20  which is fed out by the fiber sheet supply unit  110 , a fiber sheet (a prepreg or the like) already impregnated with resin may be used. 
     The core material supply unit  124  is for supplying the reinforcing fibers which are included in the core material  24  toward the molding tool  140 . The core material supply unit  124  feeds out a plurality of reinforcing fibers in a wound dry state. However, the reinforcing fibers which are fed out by the core material supply unit  124  may be reinforcing fibers already impregnated with resin. 
     The resin pool  112  is a pool that stores thermosetting resin, and a plurality of resin pools  112  are provided according to the number of fiber sheet supply units  110  and the number of core material supply units  124 . The resin pool  112  impregnates the fiber sheet  20  fed out from the fiber sheet supply unit  110  and the reinforcing fibers fed out from the core material supply unit  124  with thermosetting resin to make the fiber sheet  20  and the reinforcing fibers be in a wet state (that is, a state of being impregnated with thermosetting resin). However, in a case where the fiber sheet  20  which is fed out by the fiber sheet supply unit  110  is a fiber sheet (a prepreg or the like) already impregnated with resin, and in a case where the reinforcing fibers which are fed out by the core material supply unit  124  are in a state of being already impregnated with resin, the fiber sheet  20  and the reinforcing fibers are directly supplied from the fiber sheet supply unit  110  and the core material supply unit  124  to the molding tool  140 . 
     As shown in  FIGS. 2 and 3 , the molding tool  140  forms the pultrusion material  10  having the reinforced part  26  by drawing the reinforcing fibers and the fiber sheet  20  in a wet state along the drawing direction. 
     The molding tool  140  includes a tool main body  141 , a core part guide part  142 , and a covering part guide part  143 . The tool main body  141  has a heating part (not shown) and thermally cures the thermosetting resin which is included in the reinforcing fibers and the fiber sheet  20  in a wet state, thereby forming the pultrusion material  10 . 
     The core part guide part  142  is provided on the inlet side of the tool main body  141  and guides the reinforcing fibers bundled so as to form the core material  24 , toward the inlet side of the tool main body  141 . The core part guide part  142  is formed in an annular shape, for example, and bundles the reinforcing fibers by passing the reinforcing fibers to become the core material  24  through the inside of a circular ring. 
     The covering part guide part  143  is provided on the inlet side of the tool main body  141  and guides the core material  24  wound by at least a part of the fiber sheet  20  such that the covering part  28  covering the periphery of the core material  24  is formed, toward the inlet side of the tool main body  141 . 
     Next, a series of operations relating to a method of pultruding the pultrusion material  10  using the pultrusion device  100  described above will be described with reference to  FIG. 4 . As shown in  FIG. 4 , in the pultrusion method, an impregnation step S 1  and a pultrusion step S 2  are performed in order. 
     In the impregnation step S 1 , the fiber sheet  20  in a dry state fed out from the fiber sheet supply unit  110  is immersed in the resin pool  112 , so that the fiber sheet  20  is impregnated with thermosetting resin. Further, in the impregnation step S 1 , the reinforcing fibers in a dry state fed out from the core material supply unit  124  are immersed in the resin pool  112 , so that the reinforcing fibers are impregnated with thermosetting resin. However, in a case where the fiber sheet  20  which is fed out from the fiber sheet supply unit  110  is a fiber sheet (a prepreg or the like) already impregnated with resin, and in a case where the reinforcing fibers which are fed out from the core material supply unit  124  are in a state of being already impregnated with resin, the impregnation step S 1  in the fiber sheet  20  and the reinforcing fibers is omitted. Further, although illustration is omitted, reinforcing fibers which are included in the gap material  22  are also likewise impregnated with thermosetting resin. 
     In the pultrusion step S 2 , the fiber sheet  20  and the reinforcing fibers, which are in a wet state, are guided to the tool main body  141  by the core part guide part  142  and the covering part guide part  143  while being drawn in the drawing direction. At this time, in the pultrusion step S 2 , as shown in  FIG. 3 , a sheet folding step of folding the fiber sheet  20  so as to cover the periphery of the core material  24  is performed. That is, in the pultrusion step S 2 , the reinforcing fibers are bundled and guided by the core part guide part  142 , so that the core material  24  is formed, and in the sheet folding step, the fiber sheet  20  is folded by the covering part guide part  143 , thereby covering the periphery of the core material  24 . Then, the fiber sheet  20  and the reinforcing fibers are folded and deformed so as to form the H-shaped pultrusion material  10  having the reinforced parts  26 , and are introduced into the tool main body  141 . Further, in the pultrusion step S 2 , the H-shaped pultrusion material  10  having the reinforced parts  26  is formed by curing the thermosetting resin included in the fiber sheet  20  and the reinforcing fibers while drawing the fiber sheet  20  and the reinforcing fibers introduced into the tool main body  141  in the drawing direction. 
     As described above, according to Embodiment 1, the fiber direction of each of the reinforcing fibers which are included in the core material  24  can be oriented along the load direction, and therefore, a load which is applied to the reinforced part  26  can be adequately received by the core material  24 . For this reason, the load can be adequately received at the reinforced part  26 , so that a load due to the load can be reduced at parts other than the reinforced part  26 , and thus a plate thickness or the like can be reduced, so that the weight of the entire pultrusion material  10  can be reduced. 
     Further, according to Embodiment 1, by reinforcing a part farthest from the intersection P, it is possible to reinforce a part where stress due to bending moment to the pultrusion material  10  centered on the intersection P becomes larger. In particular, in a case where the pultrusion material  10  is formed in an H shape, it is possible to more suitably reinforce the tip portion where the stress due to the bending moment to the pultrusion material  10  becomes larger. For this reason, it is possible to more suitably perform reinforcement against a load. 
     Embodiment 2 
     Next, a pultrusion material  40  according to Embodiment 2 will be described with reference to  FIG. 5 . In Embodiment 2, in order to avoid overlapping description, portions different from those in Embodiment 1 will be described, and portions having the same configurations as in Embodiment 1 will be described with being denoted by the same reference numerals.  FIG. 5  is a sectional view schematically showing an example of a composite material according to Embodiment 2. 
     As shown in  FIG. 5 , the pultrusion material  40  of Embodiment 2 is formed in a concave shape in a cross section orthogonal to the longitudinal direction. The pultrusion material  40  having a concave shape includes the plurality of fiber sheets  20  and the core materials  24 , similar to Embodiment 1. The fiber sheet  20  and the core material  24  are the same as those in Embodiment 1, and therefore, description thereof is omitted. 
     The reinforced part  26  which is formed in the pultrusion material  40  is provided at each of two end portions which are free ends of the pultrusion material  40  having a concave shape. The reinforced part  26  is also the same as that in Embodiment 1 except that a position where the reinforced part  26  is provided in the pultrusion material  40  is different from that in Embodiment 1, and therefore, description thereof is omitted. 
     As described above, also in Embodiment 2, the fiber direction of each of the reinforcing fibers which are included in the core material  24  can be oriented along the load direction, and therefore, a load which is applied to the reinforced part  26  can be adequately received by the core material  24 . 
     Embodiment 3 
     Next, a pultrusion material  50  according to Embodiment 3 will be described with reference to  FIG. 6 . Also in Embodiment 3, in order to avoid overlapping description, portions different from those in Embodiments 1 and 2 will be described, and portions having the same configurations as in Embodiments 1 and 2 will be described with being denoted by the same reference numerals.  FIG. 6  is a sectional view schematically showing an example of a composite material according to Embodiment 3. 
     As shown in  FIG. 6 , the pultrusion material  50  of Embodiment 3 is formed in a concave shape in a cross section orthogonal to the longitudinal direction. The pultrusion material  50  having a concave shape includes the plurality of fiber sheets  20  and the core materials  24 , similar to Embodiment 1. The fiber sheet  20  and the core material  24  are the same as those in Embodiment 1, and therefore, description thereof is omitted. 
     The reinforced part  26  which is formed in the pultrusion material  50  is provided at each of two end portions which are free ends of the pultrusion material  50  having a concave shape, and the reinforced part  26  is also provided at each of two bent corner portions of the pultrusion material  50  having a concave shape. The reinforced part  26  is also the same as that in each of Embodiments 1 and 2 except that a position where the reinforced part  26  is provided in the pultrusion material  50  is different from that in each of Embodiments 1 and 2, and therefore, description thereof is omitted. 
     As described above, also in Embodiment 3, the fiber direction of each of the reinforcing fibers which are included in the core material  24  can be oriented along the load direction, and therefore, a load which is applied to the reinforced part  26  can be adequately received by the core material  24 . 
     Embodiment 4 
     Next, a pultrusion material  60  according to Embodiment 4 will be described with reference to  FIG. 7 . Also in Embodiment 4, in order to avoid overlapping description, portions different from those in Embodiments 1 to 3 will be described, and portions having the same configurations as in Embodiments 1 to 3 will be described with being denoted by the same reference numerals.  FIG. 7  is a sectional view schematically showing an example of a composite material according to Embodiment 4. 
     As shown in  FIG. 7 , the pultrusion material  60  of Embodiment 4 is formed in a T shape in a cross section orthogonal to the longitudinal direction. The pultrusion material  60  having a T shape includes the plurality of fiber sheets  20 , the gap material  22 , and the core material  24 , similar to Embodiment 1. The fiber sheet  20 , the gap material  22 , and the core material  24  are the same as those in Embodiment 1, and therefore, description thereof is omitted. 
     The reinforced part  26  which is formed in the pultrusion material  60  is provided at a tip portion which is a free end projecting from one surface side of a portion which is one straight side of the pultrusion material  60  having a T shape. The reinforced part  26  is also the same as that in each of Embodiments 1 to 3 except that a position where the reinforced part  26  is provided in the pultrusion material  60  is different from that in each of Embodiments 1 to 3, and therefore, description thereof is omitted. 
     As described above, also in Embodiment 4, the fiber direction of each of the reinforcing fibers which are included in the core material  24  can be oriented along the load direction, and therefore, a load which is applied to the reinforced part  26  can be adequately received by the core material  24 . 
     REFERENCE SIGNS LIST 
     
         
         
           
               10 : pultrusion material 
               20 : fiber sheet 
               22 : gap material 
               24 : core material (core part) 
               26 : reinforced part 
               28 : covering part 
               40 : pultrusion material (Embodiment 2) 
               50 : pultrusion material (Embodiment 3) 
               60 : pultrusion material (Embodiment 4) 
               100 : pultrusion device 
               110 : fiber sheet supply unit 
               112 : resin pool 
               124 : core material supply unit 
               140 : molding tool 
               141 : tool main body 
               142 : core part guide part 
               143 : covering part guide part