Method for molding structure and bonded structure

Abstract

Provided is a method for molding a structure, whereby it is possible to improve the tensile strength of a joined structure. Also provided is a bonded structure which can achieve improved strength. In a method for molding a structure, in an installation step, first and second prepregs (11f, 11s) are installed in a cavity (C). A first direction in which the first carbon fibers (11b) extend intersects a second direction in which the second carbon fibers (11b) extend, and the first and second prepregs (11f, 11s) overlap within a specific range (SA) in a third direction orthogonal to the first and second directions. In the mold clamping step, after the setting step, the first mold (23) and the second mold (25) are clamped. In the pressurization step, pressurization is performed so that the first and second prepregs (11f, 11s) are integrated in the cavity (C). In the injection step, an injection material (39) is injected into the cavity (C). In the hole opening step, the needle (27) is made to enter the third direction from the tip portion (27a) with respect to the specific range (SA), and a connection hole (51a) is formed by the needle (27).

Description

Technical Field

[0001] The present invention relates to a method for forming a structure and a joining structure. Background Art

[0002] A conventional joined structure is disclosed in Patent Document 1. In this joined structure, two CFRP (Carbon Fiber Reinforced Plastics) structures having carbon fibers in a base material made of a thermoplastic resin or a thermosetting resin are joined by rivets.

[0003] Compared with metal structures, CFRP structures are lightweight and high-strength, and have excellent fatigue properties and corrosion resistance. In particular, a joint structure formed by joining multiple CFRP structures by rivets does not require the use of adhesives, so in addition to shortening the joining time and reducing costs, it also has advantages such as high durability. Therefore, joint structures are widely expected to be used in parts and the like in the fields of automobiles and the like.

[0004] Prior Art Literature

[0005] Patent Literature

[0006] Patent Document 1: International Publication No. 2012 / 117737 Summary of the invention

[0007] Problems to be solved by the invention

[0008] However, since the conventional joined structure is obtained by punching out two structures using rivets, the carbon fibers in each structure are easily cut by the rivets, thereby impairing the tensile strength of the structure in the direction along the joining surface.

[0009] In particular, the carbon fibers in the first structure extend in the first direction, and the carbon fibers in the second structure extend in the second direction orthogonal to the first direction. In the joined structure formed by joining the first structure and the second structure as described above, the carbon fibers in the first structure are easily cut in the first direction by the joining holes through which the rivets are provided, and the carbon fibers in the second structure are also easily cut in the second direction by the same joining holes. Therefore, the tensile strength of the joined structure is reduced in the first direction and the second direction.

[0010] The present invention is made in view of the above-mentioned existing actual situation, and the problem to be solved is to provide a method for forming a structure that can improve the tensile strength of a joint structure. In addition, the problem of the present invention is to provide a joint structure that can achieve improved strength.

[0011] Means for solving problems

[0012] The first teaching of the method for forming a structure is characterized in that

[0013] The first teaching method of forming a structure includes:

[0014] a preparation step, in which a first prepreg having a plurality of first carbon fibers extending in one direction in a first matrix composed of a first thermoplastic resin, a second prepreg having a plurality of second carbon fibers extending in one direction in a second matrix composed of a second thermoplastic resin, a first mold, a second mold forming a cavity together with the first mold, and a needle having a pointed tip end portion are prepared;

[0015] A setting step, in which the first prepreg is set in the cavity, and the second prepreg is set in the cavity in such a manner that a first direction in which the first carbon fibers extend intersects with a second direction in which the second carbon fibers extend and overlaps in a specific range in a third direction orthogonal to the first direction and the second direction;

[0016] a mold closing step, wherein the first mold and the second mold are closed after the setting step;

[0017] a pressurizing step of performing pressurization in the mold cavity during or after the mold closing step so as to integrate the first prepreg and the second prepreg; and

[0018] A hole-forming step of causing the needle to enter the specific range from the tip portion toward the third direction during or after the pressurizing step to form a connection hole using the needle.

[0019] In the first teaching molding method, in the setting step, the first direction in which the first carbon fibers extend intersects with the second direction in which the second carbon fibers extend, and in the mold clamping step, the first prepreg and the second prepreg are integrated, thereby molding a structure such as a truss.

[0020] In particular, in the hole-opening process, the needle is inserted from the tip end portion to the third direction into the specific range where the first prepreg and the second prepreg overlap, so that the first carbon fiber in the first prepreg is gradually pressed in the radially outer direction of the needle by the tip end portion of the needle in the first matrix, and the second carbon fiber in the second prepreg is also gradually pressed in the radially outer direction of the needle by the tip end portion of the needle in the second matrix. Therefore, the carbon fibers of the first prepreg and the carbon fibers of the second prepreg are both difficult to be cut. In this way, a connection hole is formed in the obtained structure that inhibits the cutting of the surrounding carbon fibers.

[0021] In addition, in the molding method of the first teaching, since the hole-forming process is performed while the first prepreg and the second prepreg are constrained in the cavity, it becomes an embedding PCM (Pre-Preg Compression Molding) method, and the structure is unlikely to deform and has high dimensional accuracy.

[0022] The second teaching of the method for forming a structure is characterized in that

[0023] The forming method of the structure comprises:

[0024] a preparation step, in which a first prepreg having a plurality of first carbon fibers extending in one direction in a first matrix composed of a first thermoplastic resin, a first mold, a second mold forming a cavity together with the first mold, a needle having a pointed front end, and an injection material including a third thermoplastic resin and injected into the cavity are prepared;

[0025] a setting step, in which the first prepreg is set in the cavity;

[0026] a mold closing step, wherein the first mold and the second mold are closed after the setting step;

[0027] a hole-forming step in which the needle is inserted from the front end portion to a third direction orthogonal to the first direction relative to a specific range of the first prepreg to form a connection hole using the needle; and

[0028] An injection process, wherein the injection material is injected into the mold cavity before, during or after the hole-making process.

[0029] In the second teaching forming method, in the hole opening step, the needle is made to enter from the pointed tip end portion to the third direction relative to a specific range of the first prepreg, so that the first carbon fibers in the first prepreg are gradually pressed in the radially outer direction of the needle by the tip end portion of the needle in the first matrix material. Therefore, the carbon fibers in the first prepreg are difficult to be cut.

[0030] Since the injection process is performed before, during or after the hole-making process, it becomes an embedded injection molding method, and in the structure, the first prepreg and the injection material are integrally formed, and the practicality is further improved. In particular, since the injection material is injected into the cavity, the injection material also forms the connecting hole, and the connecting hole can be adjusted to a preferred shape. If the injection process is performed in the hole-making process, the temperature of the injection material can be heated in a manner that softens the first thermoplastic resin of the first prepreg, and the necessity of softening the first thermoplastic resin in a specific range during the hole-making process can be reduced or eliminated. In addition, if the injection process is performed in the hole-making process, the molding cycle time of the structure can be shortened, and the manufacturing cost can be reduced.

[0031] In this way, in the obtained structure, the cutting of the surrounding carbon fibers is suppressed and the connection holes of a preferred shape are formed.

[0032] The structure obtained by the first and second teaching molding methods is composed of thermoplastic resin and carbon fiber, and is therefore CFRTP (Carbon Fiber Reinforced Thermo Plastics, also known as thermoplastic CFRP (Carbon Fiber Reinforced Plastics). Compared with metal structures, it is lightweight and high-strength, and has excellent fatigue characteristics and corrosion resistance.

[0033] The third teaching of the joining structure is characterized by comprising a structure obtained by the above-mentioned forming method; and a counterpart which is stacked with the structure and has an insertion hole matching the joining hole,

[0034] A rivet is provided in the connection hole and the insertion hole. The rivet has a plurality of fifth carbon fibers extending in one direction in a fifth base material made of a fifth thermoplastic resin, and joins the structure to the counterpart.

[0035] The third teaching joint structure uses rivets to join the structure obtained by the first and second teachings to the object, so it is difficult to damage the tensile strength of the structure along the joining surface. In addition, the joint structure does not require the use of adhesives, so in addition to shortening the joining time and reducing costs, it also has the advantages of high durability.

[0036] Effects of the Invention

[0037] According to the method for forming a structure of the present invention, a structure capable of achieving improved tensile strength of a joined structure can be obtained. In addition, according to the joined structure of the present invention, improved strength can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1It is a three-dimensional image of the prepreg.

[0039] Figure 2 This is a schematic cross-sectional view showing the first mold, the second mold, and the needle during the preparation step of Example 1.

[0040] Figure 3 This is a schematic cross-sectional view showing the first mold, the second mold, the needle, the first prepreg, and the second prepreg during the setting step of Example 1.

[0041] Figure 4 This is a schematic cross-sectional view showing the first mold, the second mold, the needle, the first prepreg, and the second prepreg during the mold clamping step and the pressurizing step of Example 1.

[0042] Figure 5 This is a schematic enlarged cross-sectional view of the first prepreg and the second prepreg in the initial stage of the mold clamping step and the pressurizing step of Example 1.

[0043] Figure 6 This is a schematic enlarged cross-sectional view of the first prepreg and the second prepreg at the end of the mold clamping step and the pressurizing step in Example 1.

[0044] Figure 7 This is a schematic cross-sectional view showing a first mold, a second mold, a needle, a first prepreg, and a second prepreg in a hole-forming step in Example 1.

[0045] Figure 8 This is a schematic enlarged cross-sectional view of the first prepreg, the second prepreg, and the needle during the hole forming step of Example 1.

[0046] Fig. 9 This is an enlarged cross-sectional view of a main part of a structure obtained by the molding method of Example 1.

[0047] Fig.10 The structure obtained by the molding method of Example 1 is enlarged and is a partial cross-sectional plan view.

[0048] Fig.11 The structure obtained by the molding method of Example 1 is enlarged and is a partial cross-sectional rear view.

[0049] Fig.12 This is a top view of a structure obtained by the molding method of Example 1.

[0050] Fig.13 1 is a cross-sectional view of a structure and an object obtained by the molding method of Example 1.

[0051] Fig.14 This is a cross-sectional view of the main parts of the joined structure of Example 1.

[0052] Fig.15 It is a schematic cross-sectional view showing the first mold, the second mold, and the needle during the preparation step of Example 2.

[0053] Fig.16 Schematic cross-sectional views showing the first mold, the second mold, the needle, and the first prepreg during the setting step and the mold clamping step of Example 2.

[0054] Fig.17 It is a schematic cross-sectional view showing the first mold, the second mold, the needle, the first prepreg, and the injection material during the injection step and the hole-forming step of Example 2.

[0055] Fig.18 This is a cross-sectional view of two structures and a target object obtained by the molding method of Example 2.

[0056] Fig.19 This is a cross-sectional view of the main parts of the joint structure of Example 2.

[0057] Fig. 20 It is a schematic cross-sectional view showing the first mold, the second mold, and the needle during the preparation step of Example 3.

[0058] Fig.21 Schematic cross-sectional view showing the first mold, the second mold, the needle, the first prepreg, and the second prepreg during the setting step of Example 3.

[0059] Fig. 22 Schematic cross-sectional view showing the first mold, the second mold, the needle, the first prepreg, and the second prepreg during the mold clamping step and the pressurizing step of Example 3.

[0060] Fig.23 It is a schematic cross-sectional view showing the first mold, the second mold, the needle, the first prepreg, the second prepreg, and the injection material during the injection step and the hole-forming step of Example 3.

[0061] Fig.24 1 is a cross-sectional view of a structure and an object obtained by the molding method of Example 3.

[0062] Fig.25 This is a cross-sectional view of the main parts of the joint structure of Example 3. DETAILED DESCRIPTION

[0063] In the first to third teachings, the first thermoplastic resin constituting the first matrix material of the first prepreg, the second thermoplastic resin constituting the second matrix material of the second prepreg, the third thermoplastic resin constituting the injection material, the fourth thermoplastic resin capable of constituting the needle, and the fifth thermoplastic resin constituting the fifth matrix material of the rivet are preferably polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), polyvinyl acetate (PVAC), polyurethane (PUR), polytetrafluoroethylene (PTFE), acrylonitrile butadiene styrene (ABS) resin, acrylonitrile styrene copolymer The first to fifth thermoplastic resins may be the same or different.

[0064] In the first to third teachings, the first, second, fourth, and fifth carbon fibers are filaments. The first, second, fourth, and fifth carbon fibers may be PAN (Polyacrylonitrile) based or asphalt based. In addition, the first, second, fourth, and fifth carbon fibers may be of the same diameter or of different diameters. In addition, the number and density of the first carbon fibers possessed by the first prepreg, the number and density of the second carbon fibers possessed by the second prepreg, the number and density of the fourth carbon fibers that the needle can possess, and the number and density of the fifth carbon fibers possessed by the rivet may be the same or different.

[0065] In the first and second teachings, the first and second prepregs may be so-called semi-pregs that are not completely impregnated with thermoplastic resin in addition to carbon fibers being completely impregnated with thermoplastic resin. The first and second prepregs may be rods in the shape of prisms, cylinders, etc., or sheets. A third prepreg, a fourth prepreg, etc. that are the same as the first and second prepregs may also be used. In addition, in the molding direction of the first and second teachings, the shape of the structure is not limited.

[0066] In the first teaching, the pressurizing process can be performed during the mold clamping process or after the mold clamping process. If the pressurizing process is performed during the mold clamping process, the molding cycle time of the structure can be shortened, and the manufacturing cost can be reduced. If the pressurizing process is performed after the mold clamping process, it is easy to adjust the pressurizing force.

[0067] In the first teaching, the hole-making process can be performed during the pressurizing process or after the pressurizing process. If the hole-making process is performed during the pressurizing process, the molding cycle time of the structure can be shortened, and the manufacturing cost can be reduced.

[0068] In the first teaching, in the preparation process, an injection material including a third thermoplastic resin and injected into the cavity can be prepared. Then, the molding method preferably has an injection process of injecting the injection material into the cavity before the hole-making process, during the hole-making process, or after the hole-making process. In this case, it becomes an embedded injection molding method, and for the structure, not only the first prepreg and the second prepreg are integrated, but also the practicality is further improved by molding the injection material. In particular, since the injection material is injected into the cavity, the injection material also forms the connection hole, and the connection hole can be adjusted to a preferred shape. If the injection process is performed in the hole-making process, the temperature of the injection material can be heated in a manner that softens the first thermoplastic resin of the first prepreg and the second thermoplastic resin of the second prepreg, and the necessity of softening the first thermoplastic resin and the second thermoplastic resin in a specific range during the hole-making process can be reduced or eliminated. In addition, if the injection process is performed in the hole-making process, the molding cycle time of the structure can be shortened, and the manufacturing cost can be reduced.

[0069] In the first teaching, the melting point of the third thermoplastic resin is preferably higher than the melting points of the first thermoplastic resin and the second thermoplastic resin. In this case, the first thermoplastic resin and the second thermoplastic resin are reliably softened or melted by the temperature of the injection material, the integrity of the structure is increased, and the dimensional accuracy of the structure including the connection hole is improved.

[0070] In the first teaching, in the pressurizing step, it is preferred to heat the first thermoplastic resin and the second thermoplastic resin in a specific range so as to soften them. In this case, the first matrix of the first prepreg and the second matrix of the second prepreg are more likely to be integrated. The heating temperature is preferably above the thermal deformation temperature of at least one of the first thermoplastic resin and the second thermoplastic resin. It may also be below the melting point of at least one of the first thermoplastic resin and the second thermoplastic resin.

[0071] In the first teaching, in the hole-opening process, it is preferred to heat the first thermoplastic resin and the second thermoplastic resin in a specific range so as to soften them. When the injection process is not performed before or during the hole-opening process, the first and second carbon fibers are easily moved in the first and second matrix materials through the front end of the needle, and are more difficult to be cut. The heating temperature is preferably above the thermal deformation temperature of at least one of the first thermoplastic resin and the second thermoplastic resin. It can also be below the melting point of at least one of the first thermoplastic resin and the second thermoplastic resin.

[0072] In the second teaching, the melting point of the third thermoplastic resin is preferably higher than that of the first thermoplastic resin. In this case, the first thermoplastic resin softens or melts due to the temperature of the injection material, the integrity of the structure is increased, and the dimensional accuracy of the structure including the connection hole is improved.

[0073] In the second teaching, in the preparation process, a second prepreg having a plurality of second carbon fibers extending in one direction in a second matrix composed of a second thermoplastic resin can be prepared. In addition, in the setting process, the second prepreg is preferably set in the mold cavity in such a manner that the first direction in which the first carbon fiber extends intersects with the second direction in which the second carbon fiber extends within a specific range and overlaps in a third direction. Furthermore, in the hole opening process, it is preferred that a needle enters from the front end portion toward the third direction relative to the specific range, and a connection hole is formed by the needle. In this case, a connection hole can be formed on a structure that integrally includes the first prepreg and the second prepreg.

[0074] In the second teaching, the melting point of the third thermoplastic resin is preferably higher than the melting points of the first thermoplastic resin and the second thermoplastic resin. In this case, due to the temperature of the injection material, the first and second thermoplastic resins soften or melt, the integrity of the structure is increased, and the dimensional accuracy of the structure including the connection hole is improved.

[0075] In the second teaching, preferably, in the mold clamping step, the first prepreg and the second prepreg are pressed so as to be integrated in the cavity. In this case, the integrity of the structure is increased, and the dimensional accuracy of the structure including the connection hole is improved.

[0076] In the first and second teachings, the needle preferably has a plurality of fourth carbon fibers extending in one direction in a fourth matrix material made of a fourth thermoplastic resin. In this case, the needle can be used directly as a rivet made of CFRTP.

[0077] In the first and second teachings, it is preferred that the first direction and the second direction be orthogonal in the setting step. In this case, it is not necessary to weave carbon fibers, and a high-strength structure can be obtained.

[0078] In the first and second teachings, the first prepreg and the second prepreg are in the shape of rods, and the specific range may be a portion where the first prepreg and the second prepreg intersect. In this case, if a truss or lattice-shaped structure is formed, the joining holes are also formed in the portion intersecting therewith, so the joined structure can be widely used in automobiles, airplanes, spacecraft, ships, trains, buildings, etc.

[0079] The third teaching joint structure has high peel strength in the third direction because the rivet is also made of CFRTP. As the CFRTP rivet, the shaft or intermediate disclosed in Japanese Patent No. 6840410 or Japanese Patent No. 6901063 is used, and the fastening method and fastening device disclosed in these documents can be used.

[0080] In the third teaching, the counterpart may be made of metal, CFRTP, or thermosetting CFRP as long as it has an insertion hole that matches the joining hole.

[0081] Hereinafter, Examples 1 to 3 which embody the present invention will be described with reference to the drawings.

[0082] (Example 1)

[0083] Example 1 is an example in which the first teaching and the third teaching are implemented without performing the injection process. First, in the preparation process, Figure 1 The plurality of prepregs 11 shown in (A) are quadrangular prism-shaped and rod-shaped, and have a plurality of carbon fibers 11b extending only in the length direction in the matrix 11a. The matrix 11a is a thermoplastic resin. The prepregs 11 correspond to the first and second prepregs 11f and 11s, the matrix 11a corresponds to the first and second matrixes 11a composed of the first and second thermoplastic resins, and the carbon fibers 11b correspond to the first and second carbon fibers 11b.

[0084] In addition, if Figure 2 As shown in FIG. 1 , a molding device 21 is prepared. The molding device 21 includes a first mold 23, a second mold 25, and a plurality of needles 27. The first mold 23 and the second mold 25 can be relatively moved and clamped.

[0085] A first molding surface 23a is provided on the first mold 23, which is recessed from the parting surface 21a. Fig.12 and Fig.13 As shown, the first molding surface 23a allows three first prepregs 11f to extend and fit in the left-right direction of the paper. Fig.12 and Fig.13 The left-right direction of the paper is the first direction.

[0086] like Figure 2 As shown, the second mold 25 has a second molding surface 25a recessed from the parting surface 21b. The first molding surface 23a of the first mold 23 and the second molding surface 25a of the second mold 25 form a cavity C. The second molding surface 25a is composed of three first parts 251a, three second parts 252a, and countless third parts 253a.

[0087] The first portion 251a is opposite to the first forming surface 23a. Fig.12 and Fig.13 As shown, three first prepregs 11f are fitted in the horizontal direction of the paper. The sum of the depth of the first molding surface 23a from the parting surface 21a and the depth of the first portion 251a from the parting surface 21b is equal to the thickness of the first prepreg 11f.

[0088] like Figure 2 As shown, the second portion 252a is continuously recessed with the first portion 251a. The second portion 252a allows the three second prepregs 11s to be Fig.12 The up and down direction of the paper, Fig.13 In Example 1, Fig.12 The up and down direction of the paper, Figure 2 and Fig.13 The thickness direction of the paper surface of is the second direction. Therefore, the first prepreg 11f and the second prepreg 11s are orthogonal to each other and overlap in nine specific ranges SA.

[0089] like Figure 2 As shown, the length from the bottom surface of the first molding surface 23a to the bottom surface of the second portion 252a is smaller than the sum of the thickness of the first prepreg 11f and the thickness of the second prepreg 11s. Therefore, when the first mold 23 and the second mold 25 are molded together by aligning the parting surface 21a and the parting surface 21b, the first prepreg 11f and the second prepreg 11s are pressed and integrated within the specific range SA, but the first prepreg 11f and the second prepreg 11s have residual materials within each specific range SA. Therefore, the third portion 253a is formed between the first portion 251a and the second portion 252a, and the material is formed in each third portion 253a.

[0090] A pinhole 23b extending vertically toward each specific range SA is provided through the first mold 23. In addition, a pinhole 25b extending vertically toward each specific range SA is also provided through the second mold 25 in a manner consistent with the pinhole 23b. A metal needle 27 is provided in each pinhole 23b, 25b in a movable manner. The needle 27 is composed of a front end portion 27a that is tapered and pointed and a cylindrical portion 27b that extends cylindrically coaxially with the front end portion 27a. The needle 27 in the pinhole 23b protrudes from the front end portion 27a into the cavity C, and can protrude to the extent that the cylindrical portion 27b is located in the cavity C.

[0091] In addition, heating holes 23c are formed around each pinhole 23b of the first mold 23. In addition, heating holes 25c are also formed around each pinhole 25b of the second mold 25. The heating holes 23c around each pinhole 23b and the heating holes 25c around each pinhole 25b are connected to circulate a heat medium such as oil at a predetermined temperature.

[0092] In the setup process, Figure 3 As shown, a first prepreg 11f is provided in the cavity C, and a second prepreg 11s is provided. Specifically, the first prepreg 11f is fitted in the first molding surface 23a of the first mold 23, and the second prepreg 11s is fitted in the second portion 252a of the second mold 23. The first prepreg 11f and the second prepreg 11s overlap in a third direction orthogonal to the first direction and the second direction within each specific range SA. Figure 3 The up-down direction of the paper is the third direction.

[0093] In the mold clamping process and the pressurizing process, the high-temperature heat medium is circulated in the heating holes 23c and 25c. Figure 4 As shown in FIG. 1 , the first mold 23 and the second mold 25 are molded together, and pressure is applied in a manner such that the first prepreg 11f and the second prepreg 11s are integrated in the cavity C. Figure 5 As shown, the first prepreg 11f and the second prepreg 11s first contact in a specific range SA. Figure 6 As shown, the first prepreg 11 f and the second prepreg 11 s are pressurized in the specific range SA, and the remaining material is formed in each third portion 253 a of the second mold 25 .

[0094] During these periods, the first and second thermoplastic resins of the first and second prepregs 11f and 11s in the specific range SA are softened by the temperature of the heat medium. The heating temperature is appropriately set according to the thermoplastic resins of the first and second prepregs 11f and 11s. Therefore, the first and second carbon fibers 11b are deformed relatively softly, and the first and second carbon fibers 11b are not damaged. In this way, by embedding the PCM method, it is possible to suppress damage to the first and second carbon fibers 11b, and the first matrix 11a of the first prepreg 11f and the second matrix 11a of the second prepreg 11s are appropriately integrated.

[0095] Then, as a hole-opening process, a high-temperature heat medium is circulated in the heating holes 23c and 25c. Figure 7 and Figure 8 As shown, the needle 27 is made to enter from the front end portion 27a to the third direction relative to the specific range SA. As a result, the first carbon fibers 11b in the first prepreg 11f are gradually pressed in the radially outer direction of the needle 27 by the front end portion 27a of the needle 27 in the first matrix 11a. In addition, the second carbon fibers 11b in the second prepreg 11s are also gradually pressed in the radially outer direction of the needle 27 by the front end portion 27a of the needle 27 in the second matrix 11a.

[0096] During this period, the first and second thermoplastic resins of the first and second prepregs 11f and 11s in the specific range SA are softened by the temperature of the heat medium. Therefore, the first and second carbon fibers 11b are easily moved in the first and second matrix materials 11a through the front end portion 27a of the needle 27, and are more difficult to be cut. In this way, the connection hole 51a that suppresses the cutting of the surrounding first and second carbon fibers 11b is formed on the obtained structure 51.

[0097] The needle 27 is left in each connection hole 51a, and the circulation of the high-temperature heat medium to the heating holes 23c and 25c is stopped and the low-temperature heat medium is circulated to the heating holes 23c and 25c, or the circulation of the high-temperature heat medium to the heating holes 23c and 25c is stopped and the time is waited to make the first and second thermoplastic resins in the specific range SA to be at room temperature. Then, the first mold 23 and the second mold 25 are opened to obtain the structure 51. The structure 51 is formed with Figures 9-11 The connecting hole 51a is shown.

[0098] In addition, in this molding method, since the first prepreg 11f and the second prepreg 11s are constrained in the cavity C and integrated and the hole-forming process is performed, the structure 51 is difficult to deform and has high dimensional accuracy. In addition, since the pressurization process is performed in the mold closing process, the molding cycle time of the structure 51 can be shortened, and the manufacturing cost can be reduced.

[0099] The structure 51 is CFRTP, so compared with a metal structure, in addition to being lightweight and high-strength, it has excellent fatigue properties and corrosion resistance. In particular, the structure 51 can exert high tensile strength in the first direction and the second direction because the first prepreg 11f has a plurality of first carbon fibers 11b extending in the first direction in the first matrix 11a composed of the first thermoplastic resin, and the second prepreg 11s has a plurality of second carbon fibers 11b extending in the second direction in the second matrix 11a composed of the first thermoplastic resin. In addition, since the first direction and the second direction of the structure 51 are orthogonal, it is not necessary to weave the first and second carbon fibers 11b, and it becomes high strength. In addition, since the first prepreg 11f and the second prepreg 11s use the same thermoplastic resin, it is easy to soften the matrix 11a in the mold closing process or the hole opening process, and it is easy to achieve the integrity of the structure 51.

[0100] Then, in the bonding process, Fig.14 As shown, the structure 51 obtained in Example 1 is joined to the counterpart 61 by a rivet 71 made of CFRTP to form a joined structure 81. At this time, the fastening method and fastening device disclosed in Japanese Patent No. 6840410 and Japanese Patent No. 6901063 are used.

[0101] The rivet 71 is composed of a first head 71a, a second head 71b, and a shaft 71c that integrates the first head 71a and the second head 71b. The first head 71a, the second head 71b, and the shaft 71c are composed of a fifth base material 71d and a fifth carbon fiber 71e extending in a third direction, and the fifth base material 71d is composed of a fifth thermoplastic resin. As the object 61, a metal plate is used, but it can also be CFRTP or thermosetting CFRP.

[0102] The rivet 71 of the joint structure 81 obtained in this way is also CFRTP, and in particular, the fifth carbon fibers 71e in the first head 71a, the second head 71b, and the shaft 71c are not cut, so high peel strength is also exerted in the third direction.

[0103] The needle 27 of the first embodiment may be made of CFRTP instead of metal and left in the structure 51 , and the structure 51 and the counterpart 61 may be joined by deforming the needle 27 into a rivet 71 , thereby forming a joined structure 81 .

[0104] In the first embodiment, the first and second thermoplastic resins are heated to be softened in the pressurizing step and the hole-forming step. However, depending on the types of the first and second thermoplastic resins, the pressurizing step and the hole-forming step may be performed at room temperature.

[0105] In the first embodiment, the hole-forming step is performed after the pressurizing step, but the hole-forming step may be performed simultaneously with the pressurizing step. In this case, the molding cycle time of the structure 51 can be shortened, and the manufacturing cost can be reduced.

[0106] In addition, heating wires may be provided in the heating holes 23c and 25c as the molding device 21. In addition, the heating holes 23c and 25c may not be provided in the first die 23 and the second die 25, and only the heating needle 27 may be inserted through the needle holes 23b and 25b.

[0107] (Example 2)

[0108] Example 2 is an example in which the second teaching and the third teaching are implemented without preparing the second prepreg. First, in the preparation step, the second prepreg is prepared in the same manner as in Example 1. Figure 1 (A) shows a plurality of prepregs 11 .

[0109] In addition, if Fig.15 As shown in FIG. 1 , a molding device 33 is prepared. The molding device 33 includes a first mold 35, a second mold 37, and a plurality of needles 27. The first mold 35 and the second mold 37 can be relatively moved and clamped.

[0110] The first mold 35 has a first molding surface 35a recessed from the parting surface 21a. The first molding surface 35a is similar to the first embodiment, and three first prepregs 11f are extended and fitted in the horizontal direction of the paper.

[0111] The second mold 37 has a second molding surface 37a recessed from the parting surface 21b. The first molding surface 35a of the first mold 35 and the second molding surface 37a of the second mold 37 form a cavity C. The second molding surface 37a is composed of three first portions 371a and second portions 372a.

[0112] The first portion 371a is opposite to the first molding surface 35a and fits in the left-right direction of the paper surface of the three prepregs 11. The sum of the depth of the first molding surface 35a from the parting surface 21a and the depth of the first portion 371a from the parting surface 21b is equal to the thickness of the prepreg 11. When the bottom surface of each prepreg 11 is in contact with the bottom surface of the first molding surface 35a, the second portion 372a is separated from the upper surface, right surface, left surface, front surface, and rear surface of each prepreg 11.

[0113] Pinholes 35b and 37b are formed in the first and second dies 35 and 37. The structure of the pinholes 35b and 37b is the same as the pinholes 23b and 25b of Example 1. The heating holes 23c and 25c of the first and second dies 23 and 25 of Example 1 are not formed in the first and second dies 35 and 37. The other structures of the molding device 33 are the same as the molding device 21 of Example 1.

[0114] In addition, an injection material 39 is prepared. The injection material 39 includes a third thermoplastic resin and is molten, and is injected from a gate (not shown) into the cavity C. The melting point of the third thermoplastic resin of the injection material 39 is higher than the melting point of the thermoplastic resin of the prepreg 11 .

[0115] In the setup process, Fig.16 As shown, the prepreg 11 is placed in the cavity C. In the mold closing step, the first mold 35 and the second mold 37 are closed.

[0116] Then, as the injection process and the hole opening process, Fig.17 As shown, the injection material 39 is injected into the cavity C. At the same time, the needle 27 is moved from the front end portion 27a to the third direction relative to the specific range SA, and the cylindrical portion 27b of the needle 27 also penetrates the injection material 39 in the cavity C and reaches the needle hole 37b. Therefore, the carbon fibers 11b in the prepreg 11 are gradually pressed in the radially outer direction of the needle 27 by the front end portion 27a of the needle 27 in the base material 11a. Therefore, the carbon fibers 11b of the prepreg 11 are difficult to be cut.

[0117] At this time, since the injection process is performed during the hole-making process, the thermoplastic resin in the specific range SA is softened by the temperature of the injection material 39, and the carbon fiber 11 is easily moved in the base material 11a due to the front end 27a of the needle 27, and it is more difficult to be cut. During this period, the necessity of softening the thermoplastic resin in the specific range SA can be eliminated. In addition, even if the connection hole 53a formed by the needle 27 on the prepreg 11 becomes an unpreferable shape, since the injection material 39 is injected while the needle 27 remains in the connection hole 53a in the injection process, it becomes an embedded injection molding method, and the connection hole 53a can be adjusted to a preferred shape by the injection material 39. In addition, if the injection process is performed during the hole-making process, the molding cycle time of the structure 53 can be shortened, and the manufacturing cost can be reduced.

[0118] The thermoplastic resin and the injection material 39 are set to room temperature and the first mold 35 and the second mold 37 are opened to obtain a structure 53. The obtained structure 53 is composed of the prepreg 11 and the injection material 39 provided on the five surfaces of the prepreg 11 except the bottom surface. A connection hole 53a of a preferred shape that suppresses the cutting of the surrounding carbon fibers 11b is formed in each structure 53.

[0119] like Fig.18 As shown, three structures 53 are arranged in the thickness direction of the paper surface, and three structures 53 are arranged in the left-right direction, and the object 61 is prepared in the same manner as in Example 1. The prepreg 11 of the structures 53 arranged in the thickness direction of the paper surface is equivalent to the first prepreg 11f, and the prepreg 11 of the structures 53 arranged in the left-right direction of the paper surface is equivalent to the second prepreg 11s.

[0120] Then, if Fig.19 As shown, each structure 53 is joined to the counterpart 61 by using a rivet 71 made of CFRTP in the same manner as in Example 1. In this way, a joined structure 83 is obtained.

[0121] The structure 53 of the second embodiment can also achieve the same effects as those of the first embodiment. In addition, the joined structure 83 of the second embodiment can also achieve the same effects as those of the first embodiment.

[0122] The needle 27 of the second embodiment is also not made of metal, but may be made of CFRTP and remain in the structure 53 , and the structure 53 and the counterpart 61 may be joined by deforming the needle 27 into the rivet 71 , thereby forming a joined structure 83 .

[0123] In Example 2, the injection process is performed during the hole-making process, but the injection process may be performed before or after the hole-making process. When the injection process is performed after the hole-making process, the needle 27 remains in the cavity C, and the connection hole is also formed in the injected material 39.

[0124] (Example 3)

[0125] Example 3 is an example in which the first teaching and the third teaching of performing the injection process are implemented. In other words, Example 3 is an example in which the second teaching and the third teaching of preparing the second prepreg are implemented. First, in the preparation process, the second prepreg is prepared in the same manner as in Examples 1 and 2. Figure 1 (A) shows a plurality of prepregs 11 .

[0126] In addition, if Fig. 20 As shown in FIG. 1 , a molding device 41 is prepared. The molding device 41 includes a first mold 43, a second mold 45, and a plurality of needles 27. The first mold 43 and the second mold 45 can be relatively moved and clamped.

[0127] A first molding surface 43a is provided recessed from the parting surface 21a on the first mold 43. The first molding surface 43a is similar to the first embodiment, and three first prepregs 11f are extended and fitted in the horizontal direction of the paper.

[0128] The second mold 45 has a second molding surface 45a recessed from the parting surface 21b. The first molding surface 43a of the first mold 43 and the second molding surface 45a of the second mold 45 form a cavity C. The second molding surface 45a includes three first portions 451a, three second portions 452a, and a third portion 453a.

[0129] The first part 451a faces the first molding surface 43a, and fits three first prepregs 11f in the horizontal direction of the paper. The sum of the depth of the first molding surface 43a from the parting surface 21a and the depth of the first part 451a from the parting surface 21b is equal to the thickness of the first prepreg 11f.

[0130] The second portion 452a is recessed continuously with the first portion 451a. The second portion 452a allows the three second prepregs 11s to be placed in a substantially rectangular shape. Fig. 20 Therefore, the first prepreg 11f and the second prepreg 11s are orthogonal to each other and overlap in nine specific ranges SA.

[0131] When the bottom surface of the first prepreg 11f contacts the bottom surface of the first molding surface 43a and the second prepreg 11s fits with the second portion 452a, the third portion 453a is separated from the top, right, left, front and rear surfaces of the first and second prepregs 11f, 11s.

[0132] The length from the bottom surface of the first molding surface 43a to the bottom surface of the second portion 452a is smaller than the sum of the thickness of the first prepreg 11f and the thickness of the second prepreg 11s. Therefore, when the first mold 43 and the second mold 45 are closed by aligning the parting surface 21a and the parting surface 21b, the first prepreg 11f and the second prepreg 11s are pressed and integrated in the specific range SA, but the first prepreg 11f and the second prepreg 11s have excess material in each specific range SA. Therefore, the material bulges toward the third portion 453a.

[0133] Pinholes 43b and 45b are formed in the first and second dies 43 and 45. The pinholes 43b and 45b have the same structure as the pinholes 23b, 25b, 35b and 37b of Examples 1 and 2. The heating holes 23c and 25c of the first and second dies 23 and 25 of Example 1 are not formed in the first and second dies 43 and 45. The other structures of the molding device 41 are the same as the molding device 21 of Example 1.

[0134] Injection material 39 is prepared. Injection material 39 includes a third thermoplastic resin and is molten and injected from a gate (not shown) into cavity C. The third thermoplastic resin of injection material 39 has a higher melting point than the first and second thermoplastic resins of first and second prepregs 11f and 11s.

[0135] In the setup process, Fig.21 As shown in FIG. 1 , similarly to the first embodiment, the first and second prepregs 11f and 11s are arranged in the cavity C. In addition, in the mold closing step and the pressurizing step, as shown in FIG. Fig. 22 As shown, the first mold 43 and the second mold 45 are clamped together, and pressure is applied in the cavity C so that the first prepreg 11f and the second prepreg 11s are integrated.

[0136] Then, as the injection process and the hole opening process, Fig.23 As shown, the injection material 39 is injected into the cavity C. At the same time, the needle 27 is made to enter from the front end portion 27a to the third direction relative to the specific range SA, and the cylindrical portion 27b of the needle 27 also penetrates the injection material 39 in the cavity C and reaches the needle hole 37b. Therefore, the first and second carbon fibers 11b in the first and second prepregs 11f and 11s are gradually pressed in the radially outer direction of the needle 27 by the front end portion 27a of the needle 27 in the first and second base materials 11a. Therefore, the first and second carbon fibers 11b of the first and second prepregs 11f and 11s are difficult to be cut.

[0137] At this time, since the injection process is performed in the hole-opening process, the first and second thermoplastic resins in the specific range SA are softened by the temperature of the injection material 39, and the first and second carbon fibers 11b are easily moved in the first and second base materials 11a due to the front end 27a of the needle 27, and are more difficult to be cut. During this period, the necessity of softening the first and second thermoplastic resins in the specific range SA can be eliminated. In addition, even if it is assumed that the connection hole 55a formed by the needle 27 on the first and second prepregs 11f and 11s becomes an unpreferable shape, since the injection material 39 is injected while the needle 27 remains in the connection hole 55a in the injection process, it becomes an embedded injection molding method, and the connection hole 55a can be adjusted to a preferred shape by the injection material 39. In addition, if the injection process is performed in the hole-opening process, the molding cycle time of the structure 53 can be shortened, and the manufacturing cost can be reduced.

[0138] The first and second thermoplastic resins and the injection material 39 are set to room temperature and the first mold 43 and the second mold 45 are opened to obtain a structure 55. The obtained structure 55 is composed of the first and second prepregs 11f and 11s and the injection material 39 provided on the five surfaces of the first and second prepregs 11f and 11s except the bottom surface. In each structure 55, the first and second carbon fibers 11b are prevented from being cut and the connection holes 55a of a preferred shape are formed.

[0139] like Fig.24 As shown, three structures 55 are arranged in the thickness direction of the paper, and the object 61 is prepared in the same manner as in Examples 1 and 2. Then, as shown in FIG. Fig.25 As shown, the structure 55 and the counterpart 61 are joined by the rivets 71 made of CFRTP in the same manner as in Examples 1 and 2. In this way, a joined structure 85 is obtained.

[0140] The structure 55 of the third embodiment can also achieve the same effects as those of the first and second embodiments. In addition, the joined structure 85 of the third embodiment can also achieve the same effects as those of the first and second embodiments.

[0141] The needle 27 of the third embodiment is also not made of metal, but may be made of CFRTP and remain in the structure 55 , and the structure 55 and the counterpart 61 may be joined by deforming the needle 27 into a rivet 71 , thereby forming a joined structure 85 .

[0142] In addition, in the above-mentioned embodiment 3, the injection process is also performed during the hole-making process, but the injection process may be performed before or after the hole-making process. In the case where the injection process is performed before or after the hole-making process, the needle 27 remains in the cavity C, and the connection hole is also formed in the injection material 39.

[0143] The inventors set the thermoplastic resin of the prepreg 11 and the injection material to PP (polypropylene) to form a plurality of structures 53 of Example 2, and manufactured a grid-shaped joint structure 83 from each structure 53. The joint structure 83 is a lid member of a battery case, and is light and high in strength, and has excellent fatigue characteristics and corrosion resistance.

[0144] As mentioned above, although the present invention has been described based on Embodiments 1 to 3, the present invention is not limited to the above-mentioned Embodiments 1 to 3, and it is apparent that the present invention can be applied with appropriate changes within the scope not departing from the gist thereof.

[0145] For example, in Examples 1 to 3, Figure 1 (A) shows a rectangular prism-shaped rod-shaped prepreg 11, but it is also possible to use Figure 1 The cylindrical rod-shaped prepreg 13 shown in (B) is also provided with a plurality of carbon fibers 13b extending only in the longitudinal direction in the matrix 13a. Figure 1 The sheet-shaped prepreg 15 shown in (C) is also provided in the base material 15a with a plurality of carbon fibers 15b extending only in the longitudinal direction.

[0146] In addition, in Examples 2 and 3, the injection material 39 is provided on the five surfaces of the prepreg 11 or the first and second prepregs 11f, 11s except the bottom surface, but the injection material may be provided on the entire surface of the prepreg 11 or the first and second prepregs 11f, 11s, or only on a specific portion.

[0147] In addition, according to the present invention, in order to manufacture lightweight, high-strength, high-heat-resistant and high-wear-resistant parts, the thermoplastic resin of the prepreg is set to low-melting-point PAEK, and the injection material is set to PEEK, so that a structure or a joined structure using super engineering plastics can be obtained.

[0148] It should be noted that the first and second prepregs 11 , 13 , 15 have carbon fibers 11 b , 13 b , 15 b extending only in the longitudinal direction, but may also have carbon fibers extending in the longitudinal direction and twisting.

[0149] Industrial Applicability

[0150] The present invention can be used for parts and the like in the fields of automobiles, airplanes, spacecraft, ships, trains, buildings, and the like.

[0151] Description of Reference Numerals

[0152] 11a, 13a, 15a…base material (first base material, second base material)

[0153] 11b, 13b, 15b, 71e...carbon fiber (first carbon fiber, second carbon fiber, 71e...fourth carbon fiber)

[0154] 11, 13, 15...prepreg (11f...first prepreg, 11s...second prepreg)

[0155] 23, 35, 43…The first mold

[0156] C…Cavity

[0157] 25, 37, 45…Second mold

[0158] 27a…Front end

[0159] 27…needle

[0160] SA…Specific range

[0161] 51a, 53a, 55a...connection holes

[0162] 51, 53, 55…Structure

[0163] 39…Injection materials

[0164] 61a…Insert hole

[0165] 61…Object

[0166] 71…Rivets

[0167] 81, 83…joining structure.

Claims

1. A method for forming a structure, characterized in that: The forming method of the structure comprises: a preparation step, in which a first prepreg having a plurality of first carbon fibers extending in one direction in a first matrix composed of a first thermoplastic resin, a second prepreg having a plurality of second carbon fibers extending in one direction in a second matrix composed of a second thermoplastic resin, a first mold, a second mold forming a cavity together with the first mold, and a needle having a pointed tip end portion are prepared; A setting step, in which the first prepreg is set in the cavity, and the second prepreg is set in the cavity in such a manner that a first direction in which the first carbon fibers extend intersects with a second direction in which the second carbon fibers extend and overlaps in a specific range in a third direction orthogonal to the first direction and the second direction; a mold closing step, wherein the mold closing step closes the first mold and the second mold after the setting step; a pressurizing step of performing pressurization in the mold cavity during or after the mold closing step so as to integrate the first prepreg and the second prepreg; and A hole-forming step of causing the needle to enter the specific range from the tip portion toward the third direction during or after the pressurizing step to form a connection hole using the needle.

2. The method for forming a structure according to claim 1, wherein: In the preparation step, an injection material including a third thermoplastic resin and to be injected into the cavity is prepared, The molding method of the structure includes an injection process, wherein the injection material is injected into the mold cavity before, during or after the hole-making process.

3. The method for forming a structure according to claim 2, wherein: The third thermoplastic resin has a higher melting point than the first thermoplastic resin and the second thermoplastic resin.

4. The method for forming a structure according to any one of claims 1 to 3, wherein: In the pressurizing step, the first thermoplastic resin and the second thermoplastic resin are heated so as to soften the specific ranges.

5. The method for forming a structure according to any one of claims 1 to 4, wherein: In the hole forming step, the first thermoplastic resin and the second thermoplastic resin are heated so as to soften the specific ranges.

6. A method for forming a structure, characterized in that: The forming method of the structure comprises: a preparation step, in which a first prepreg having a plurality of first carbon fibers extending in one direction in a first matrix composed of a first thermoplastic resin, a first mold, a second mold forming a cavity together with the first mold, a needle having a pointed front end, and an injection material including a third thermoplastic resin and injected into the cavity are prepared; a setting step, in which the first prepreg is set in the cavity; a mold closing step, wherein the mold closing step closes the first mold and the second mold after the setting step; a hole-forming step in which the needle is inserted from the front end portion to a third direction orthogonal to the first direction relative to a specific range of the first prepreg to form a connection hole using the needle; and An injection process, wherein the injection material is injected into the mold cavity before, during or after the hole-making process.

7. The method for forming a structure according to claim 6, wherein: The third thermoplastic resin has a higher melting point than the first thermoplastic resin.

8. The method for forming a structure according to claim 6, wherein: In the preparation step, a second prepreg having a plurality of second carbon fibers extending in one direction in a second matrix material composed of a second thermoplastic resin is prepared. In the setting step, the second prepreg is set in the cavity in the specific range in such a manner that the first direction in which the first carbon fibers extend intersects with the second direction in which the second carbon fibers extend and overlaps in the third direction. In the hole opening step, the needle is caused to enter the specific range from the tip portion toward the third direction, and the connection hole is formed by the needle.

9. The method for forming a structure according to claim 8, wherein: The third thermoplastic resin has a higher melting point than the first thermoplastic resin and the second thermoplastic resin.

10. The method for forming a structure according to claim 8 or 9, wherein: The method for molding the structure includes a pressurizing step of performing pressurization in the mold clamping step so as to integrate the first prepreg and the second prepreg in the cavity.

11. The method for forming a structure according to any one of claims 1 to 10, wherein: The needle has a plurality of fourth carbon fibers extending in one direction in a fourth matrix material made of a fourth thermoplastic resin.

12. The method for forming a structure according to any one of claims 1 to 5 or claims 8 to 10, wherein: In the setting step, the first direction and the second direction are made to be orthogonal to each other.

13. The method for forming a structure according to claim 12, wherein: The first prepreg and the second prepreg are in a rod shape, The specific range is a portion where the first prepreg and the second prepreg intersect.

14. A joint structure, characterized in that: The joint structure comprises: The structure obtained by the molding method of claims 1 to 13; and an object member stacked with the structure and having an insertion hole matching the engagement hole, A rivet is provided in the connection hole and the insertion hole. The rivet has a plurality of fifth carbon fibers extending in one direction in a fifth base material made of a fifth thermoplastic resin, and joins the structure to the counterpart.

Images