Method for manufacturing tubular bodies
The method addresses the challenge of forming tubular laminates with low-tack prepreg sheets by creating tubular primary members with free edges and heat molding, allowing efficient production of tubular bodies.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- SUMITOMO RUBBER INDUSTRIES LTD
- Filing Date
- 2022-08-19
- Publication Date
- 2026-07-29
AI Technical Summary
Prepreg sheets with low tackiness and drape properties make it difficult to form tubular laminates, especially when using thermoplastic resins, which lack the necessary flexibility for winding around mandrels or tubes.
A method involving a first step to create a substantially tubular primary processed member from prepreg sheets, a second step to laminate multiple primary processed members, and a third step to heat mold the laminate, where the primary processed members have free edges to facilitate easy formation of a cylindrical laminate.
Enables the easy formation of a cylindrical laminate and subsequent manufacturing of a tubular body even with prepreg sheets having low tack and/or drape properties, improving manufacturing efficiency and product quality.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to a method for manufacturing a tubular body and the like.
Background Art
[0002] In recent years, tubular bodies made of fiber-reinforced resins with high specific strength have been adopted, for example, in golf club shafts, racquets, fishing rods, bicycle frames, and the like. As methods for manufacturing this type of tubular body, for example, there are a wrapping method and an internal pressure method (see, for example, Patent Documents 1 and 2 below).
[0003] In the wrapping method, first, a prepreg sheet of a fiber-reinforced resin is wound around an iron mandrel in a desired number of layers to form a tubular laminate. Next, a resin wrapping tape is spirally wound around the tubular laminate while applying tension, and then it is heat-molded in a curing furnace. Thereby, a tubular body made of a fiber-reinforced resin in which the resin material of the prepreg sheet is cured is manufactured.
[0004] On the other hand, in the internal pressure method, first, a prepreg sheet is wound around the outer peripheral surface side of a heat-resistant resin tube in a desired number of layers to form a tubular laminate. Next, the laminate is placed in a mold together with the tube. Then, while heating the mold and expanding the tube, the laminate is pressed against the molding surface of the mold and heat-molded. Thereafter, by cooling the molded product, a tubular body made of a fiber-reinforced resin is manufactured.
Prior Art Documents
Patent Documents
[0005]
Patent Document 1
Patent Document 2
Summary of the Invention
Problems to be Solved by the Invention
[0006] In recent years, various types of prepreg sheets with reduced resin impregnation have been put into practical use in order to further reduce the weight of tubular bodies. However, these types of prepreg sheets usually have extremely low tackiness, making it difficult to form tubular laminates on mandrels or tubes.
[0007] Furthermore, prepreg sheets made from thermoplastic resins have low tackiness and high bending rigidity at room temperature. Therefore, this type of prepreg sheet lacks the appropriate flexibility (hereinafter also referred to as "drapeability") necessary for winding along mandrels or tubes. Consequently, it is difficult to form tubular laminates using prepreg sheets made from thermoplastic resins.
[0008] This invention was devised in view of the above-mentioned problems, and its main objective is to provide a method for manufacturing a tubular body that allows for easy formation of a cylindrical laminate and manufacture of a tubular body, even when using a prepreg sheet with low tack and / or drape properties. [Means for solving the problem]
[0009] The present invention relates to a method for manufacturing a tubular body, comprising: a first step of obtaining a substantially tubular primary processed member from at least one prepreg sheet containing fibers and resin; a second step of obtaining a prepreg laminate by laminating a plurality of the primary processed members; and a third step of obtaining a tubular body by heat molding the prepreg laminate, wherein the primary processed member has a first edge and a second edge extending in the axial direction of a substantially tubular shape, and the first edge and the second edge are each free ends. [Effects of the Invention]
[0010] In the method for manufacturing a tubular body of the present invention, by employing the above-described steps, it is possible to easily form a cylindrical laminate and manufacture a tubular body even when using a prepreg sheet with low tack and / or drape properties. [Brief explanation of the drawing]
[0011] [Figure 1] It is a front view of a tubular body manufactured by the manufacturing method of this embodiment. [Figure 2] It is a sectional view taken along line II-II of FIG. 1. [Figure 3] It is a flowchart showing the specific procedure of the manufacturing method of the tubular body of this embodiment. [Figure 4] It is a perspective view of a prepreg sheet. [Figure 5] It is a perspective view of a first primary processed member. [Figure 6] It is a perspective view of a second primary processed member. [Figure 7] It is a flowchart showing the specific procedure of the first step of this embodiment. [Figure 8] (A) and (B) are cross-sectional views of a mold showing an example of a primary processing step. [Figure 9] It is a cross-sectional view of a mold showing an example of a primary processing step. [Figure 10] It is a cross-sectional view of a mold showing an example of a primary processing step. [Figure 11] It is a cross-sectional view showing some examples of the first primary processed member. [Figure 12] It is a cross-sectional view showing an example of the second primary processed member. [Figure 13] It is a cross-sectional view of a prepreg laminate for explaining an example of the second step. [Figure 14] It is a cross-sectional view of a prepreg laminate for explaining an example of the third step. [Figure 15] It is an exploded perspective view of a laminated prepreg sheet. [Figure 16] It is a cross-sectional view of a laminated prepreg sheet. [Figure 17] It is a perspective view of a mold of other embodiments. [Figure 18] It is a cross-sectional view of the tubular body of the example. [[ID=5⑨]]
MODE FOR CARRYING OUT THE INVENTION
[0012] Hereinafter, some embodiments of the present invention will be described. The representative embodiments disclosed below are not intended to limit the present invention in any way. Further, the following embodiments can be used alone or in various combinations. Furthermore, in the following embodiments, the same or common elements are denoted by the same reference numerals, and redundant descriptions are omitted.
[0013] FIG. 1 is a front view of a tubular body 1 made of a fiber-reinforced resin obtained by the manufacturing method of the present embodiment. FIG. 2 is a cross-sectional view taken along line II-II thereof. The tubular body 1 manufactured by the present invention is applicable to various uses such as, for example, a golf club shaft, a racket, a fishing rod, a bicycle frame, and various structural tubes.
[0014] As shown in FIGS. 1 and 2, the tubular body 1 is a composite of fibers 2 and a cured resin 3. The tubular body 1 of the present embodiment is formed, for example, in a circular tube shape. The tubular body 1 is not limited to a circular tube shape, and may be a polygonal tube.
[0015] FIG. 3 is a flowchart showing the specific procedure of the manufacturing method of the tubular body 1 of the present embodiment. In the present embodiment, the manufacturing method of the tubular body 1 includes a first step S1, a second step S2, and a third step S3.
[0016] [First Step] In the present embodiment, the first step S1 is a step of obtaining a substantially tubular primary processed member 11 as shown in FIG. 5 or FIG. 6 from at least one prepreg sheet 10 as shown in FIG. 4.
[0017] The prepreg sheet 10 is a sheet-like intermediate material in which fibers 2 and an uncured resin 3 are combined.
[0018] Examples of fiber 2 include carbon fiber, glass fiber, metal fiber (boron, titanium, tungsten, stainless steel, etc.), aramid fiber, etc., and one or more of these may be used. In this embodiment, fiber 2 is substantially oriented in one direction. In other embodiments, fiber 2 may be woven.
[0019] As resin 3, for example, a thermosetting resin or a thermoplastic resin can be used. Examples of thermosetting resins include epoxy resins, unsaturated polyester resins, phenolic resins, vinyl ester resins, etc., and one or more of these may be used. Examples of thermoplastic resins include polysulfone, polyethersulfone, polyetherketone, polyetheretherketone, aromatic polyamide, aromatic polyester, aromatic polycarbonate, polyetherimide, polyarylene oxide, thermoplastic polyimide, polyamideimide, polyphenylene sulfide, polyethylene, polypropylene, etc., and one or more of these may be used.
[0020] The prepreg sheet 10 in this embodiment is made of a thermoplastic resin. This type of prepreg sheet 10 typically has low tack and drape properties at room temperature (25°C), making it suitable for the manufacturing method of the present invention. However, the present invention may also be carried out using a prepreg sheet 10 made of a thermosetting resin. This is because, even with such a prepreg, the tack properties decrease significantly as the resin content decreases.
[0021] Figure 5 is a perspective view of a primary processed member 11 of one example of this embodiment. The primary processed member 11 is obtained by forming a prepreg sheet 10 into a substantially tubular shape. At room temperature, the primary processed member 11 maintains the shape shown in Figure 5.
[0022] The primary processed member 11 comprises a first edge 11a and a second edge 11b extending in the axial direction CL. These first and second edges define the circumferential edges of the primary processed member 11. The first and second edges 11a and 11b are each free ends. Therefore, the primary processed member 11 as a whole is curled in a tubular shape, but it is not a completely closed tube in the circumferential direction. In this specification and in the claims, “substantially tubular” is understood as a term describing the shape of such a primary processed member 11.
[0023] The primary processing member 11 shown in Figure 5 is a first primary processing member 11A that is substantially cylindrical in shape, with a circumferential angle from the first edge 11a to the second edge 11b exceeding 360 degrees. Such a first primary processing member 11A has an overlapping portion 11c where the end on the first edge 11a side and the end on the second edge 11b side overlap in the radial direction of the primary processing member 11.
[0024] Furthermore, as shown in Figure 6, the primary processed member 11 may include a substantially cylindrical second primary processed member 11B in which the circumferential angle from the first edge 11a to the second edge 11b is less than 360 degrees. Such a second primary processed member 11B has a gap portion 11d, which is a circumferential gap between the first edge 11a and the second edge 11b. In the second primary processed member 11B, the circumferential angle from the first edge 11a to the second edge 11b is, for example, greater than 180 degrees, preferably 225 degrees or more, and more preferably 270 degrees or more.
[0025] Next, an example of the specific procedure of the first step S1 for obtaining the primary processed member 11 as described above will be explained with reference to Figure 7. Figure 7 is a flowchart showing the specific procedure of the first step S1.
[0026] As shown in Figure 7, in the first step S1, at least one primary processing step S100 is performed. The primary processing step S100 includes steps S11 to S13.
[0027] In step S11 of the primary processing step S100, the prepreg sheet 10 is placed inside the mold 21, as shown in Figure 8(A).
[0028] In this embodiment, the mold 21 has a molding surface 20 that is curved in an arc shape. The mold 21 in this embodiment has a tubular shape in which the molding surface 20 is cylindrical. The radius of curvature (inner diameter) R1 is constant in the axial direction of the mold 21. However, the shape of the mold 21 is not limited to the tubular shape described above.
[0029] Figure 8(A) shows a cross-section perpendicular to the axial direction of the mold 21. In the cross-section of Figure 8(A), the width W of the prepreg sheet 10 (i.e., the radial length of the mold 21) can be appropriately adjusted to a size that prevents excessive bending of the prepreg sheet 10 when inserted into the mold 21. In a preferred example, the width W of the prepreg sheet 10 is preferably about 90% to 110% or less of the inner diameter D of the mold 21.
[0030] Next, in step S12 of the first step S1 of this embodiment, the prepreg sheet 10 is heated together with the mold 21. As a result, the prepreg sheet 10 softens and deforms to conform to the molding surface 20 of the mold 21. In this step S12, the intention is to pre-curve the prepreg sheet 10 in order to improve its ability to be wrapped around a mandrel or the like. Therefore, in this step S12, the intention is not to deform or harden the prepreg sheet 10 into the final product shape.
[0031] The heating temperature of the prepreg sheet 10 in step S12 can be appropriately determined within the temperature range in which the prepreg sheet 10 softens and becomes bendable, for example, it can be set to a lower temperature within that range. If the resin 3 of the prepreg sheet 10 is thermoplastic, the heating temperature in step S12 may be lower than the melting point of the resin 3. If the resin 3 of the prepreg sheet 10 is thermosetting, the heating temperature in step S12 is lower than the polymerization reaction temperature of the resin 3. In either case, the heating time is, for example, 3 to 10 minutes, with 3 to 5 minutes being more preferable.
[0032] Figure 8(B) shows the state of the prepreg sheet 10 after process S12. The prepreg sheet 10 softens when heated and curves in an arc shape to conform to the molding surface 20. Such deformation is achieved, for example, by utilizing the weight of the prepreg sheet 10. In other examples, the prepreg sheet 10 may be pressed against the molding surface 20 using a jig or the like to accelerate the deformation of the softened prepreg sheet 10.
[0033] Next, in step S13 of the first step S1 of this embodiment, the deformed prepreg sheet 10 is cooled and then removed from the mold 21. The cooling temperature of the prepreg sheet 10 is set to a temperature at which the resin 3 hardens to the extent that the prepreg sheet 10 can maintain its curved shape along the molding surface 20 on its own in a free state without external force acting on it. Therefore, the prepreg sheet 10 removed from the mold 21 maintains a curled shape along the molding surface 20 in a free state.
[0034] The above three steps S11, S12, and S13 are the details of the primary processing step S100. The primary processing step S100 may be performed only once or may be repeated multiple times. In the latter case, it is desirable that the primary processing step S100 be repeated multiple times, gradually decreasing the radius of curvature of the molding surface 20 of the mold 21, such as R2 and R3, as shown in Figures 9 and 10 (step S14).
[0035] When gradually reducing the radius of curvature of mold 21 as R1, R2, R3, etc., it is desirable that the radius of curvature of mold 21 in the next process be 80% or more of the radius of curvature of mold 21 used in the immediately preceding process. If the radius of curvature of mold 21 is reduced too quickly, large bending deformation may occur in the prepreg sheet 10 when inserting the prepreg sheet 10 into mold 21, potentially causing the fibers 2 to break or other damage.
[0036] Figures 11 and 12 schematically show the cross-sectional shapes of various primary processed members 11 obtained in the first step S1. Figure 11 shows the first primary processed member 11A curled with various radii of curvature, and Figure 12 shows the second primary processed member 11B. When molding the first primary processed member 11A, it is desirable that the surface of the prepreg sheet 10 be covered with a release sheet or release agent made of fluororesin or the like before being placed in the mold 21. This helps to prevent the first edge 11a and the second edge 11b from sticking to each other in the overlapping portion 11c.
[0037] [Second process] Returning to Figure 3, the manufacturing method of this embodiment involves a first step S1 followed by a second step S2. In the second step S2, as schematically shown in Figure 13, a plurality of primary processed members 11 are laminated to obtain a prepreg laminate 30. In the second step S2 of this embodiment, a plurality of primary processed members 11 (six in this example) are laminated on the outside of a core material 40. The core material 40 can be, for example, expandable, and in this embodiment, a heat-resistant resin tube is used. Note that in Figure 13, black circles are added to make it easier to understand the positions of the first edge 11a and the second edge 11b of the primary processed member 11.
[0038] Since the primary processed member 11 is preformed into a roughly tubular shape in the first step S1, it can be wrapped around the core material 40 and laminated even if it has low tackiness and drape properties. Furthermore, since the first edge 11a and the second edge 11b of the primary processed member 11 are free ends, the winding diameter can be varied by changing the length of the lap portion 11c and / or gap portion 11d. Therefore, the primary processed member 11 can be easily laminated to conform to the diameter of the core material 40. Moreover, by using the primary processed member 11, the second step S2 can be carried out, for example, in a room temperature environment.
[0039] In a preferred embodiment, in the second step S2, the first edges 11a and second edges 11b of the plurality of primary processed members 11 are positioned at different locations in the circumferential direction when forming the prepreg laminate 30. This is preferable because the overlapping portions 11c (or gap portions 11d) of the plurality of primary processed members 11 are distributed in the circumferential direction, thereby resulting in a more uniform distribution of the fibers 2 and resin 3 in the circumferential direction.
[0040] [3rd step] Next, in the manufacturing method of this embodiment, the third step S3 is performed after the second step S2. In the third step S3, the resin 3 is cured by heat molding the prepreg laminate 30 to obtain the tubular body 1.
[0041] As shown in Figure 14, the third step S3 can be carried out, for example, by the internal pressure method. Specifically, in the third step S3, the prepreg laminate 30 is first placed together with the core material 40 in the cavity of the mold 50. The mold 50 includes, for example, a separable upper mold 50A and a lower mold 50B. The cavity is defined by the molding surfaces 50i of the upper mold 50A and the lower mold 50B.
[0042] Next, the mold 50 is heated. High-pressure fluid is also supplied to the core material 40 (tube). This causes the core material 40 to expand, pressurizing the inside of the prepreg laminate 30. The prepreg laminate 30, subjected to heat and internal pressure, expands radially and is pressed against the molding surface 50i of the mold 50. Each primary processed member 11 of the prepreg laminate 30 has its first edge 11a and second edge 11b as free ends, so it can easily expand radially while sliding slightly in the circumferential direction. The core material 40 does not necessarily have to be a tube; the inside of the prepreg laminate 30 may be pressurized using various mechanical jigs or the like.
[0043] In the third step S3, the prepreg laminate 30 is intended to be molded into its final shape. Therefore, the temperature and time for the heat molding in the third step S3 are set to a temperature and time that allows the resin 3 of the primary processed member 11 to be plasticized and molded into a predetermined shape. For example, if the resin 3 of the primary processed member 11 is thermoplastic, the primary processed member 11 is heated to a temperature above the melting point of the resin 3. This causes the resin 3 to become fluid. In this state, the prepreg laminate 30 is pressurized from the inside, causing the air between the primary processed members 11 to be expelled to the outside, and the primary processed members 11 to adhere closely to each other and change into the desired shape. If the resin 3 of the prepreg sheet 10 is thermosetting, the prepreg sheet 10 is heated to a temperature above the polymerization reaction temperature of the resin 3. This causes a curing reaction in the resin 3.
[0044] In this embodiment, since the resin 3 of the prepreg sheet 10 is thermoplastic, a cooling step is performed after the heat molding in the third step S3 is completed. In the cooling step, the molded product is cooled to, for example, room temperature.
[0045] Through the above process, a tubular body 1, which is a hardened laminate of multiple primary processed members 11, is formed. Then, the upper mold 50A and the lower mold 50B are opened and the tubular body 1 is removed from the cavity of the mold 50.
[0046] As described above, in the manufacturing method of the tubular body 1 of this embodiment, even when using a prepreg sheet with low tack and / or drape properties, a cylindrical laminate can be easily formed, and thus a tubular body can be manufactured.
[0047] [Variations of prepreg sheets] Figures 15 and 16 show another example of the first step S1. As shown in Figure 15, in this example, at least one prepreg sheet for obtaining the primary processed member 11 consists of a laminated prepreg sheet made by stacking multiple prepreg sheets. In a preferred example, the multiple prepreg sheets used are multiple prepreg sheets 10A and 10B in which the orientation angles of the fibers 2 differ from each other. For example, prepreg sheet 10A has fibers 2 having a first angle with respect to the axial direction CL, and prepreg sheet 10B has fibers 2 having a second angle with respect to the axial direction CL that is different from the first angle. The difference between these angles is preferably, for example, 90°.
[0048] In this example, prepreg sheets 10A and 10B are sequentially placed on a release sheet 60 made of fluororesin or the like, and then, as shown in Figure 16, both prepreg sheets 10A and 10B are covered with the release sheet 60.
[0049] A fiber-reinforced resin tubular body 1 is typically manufactured by laminating multiple prepreg sheets. Therefore, the productivity of the tubular body 1 can be improved by pre-layering multiple prepreg sheets 10A and 10B and molding them as a single integrated primary processed member 11.
[0050] Furthermore, since a prepreg sheet in which the fibers 2 are inclined with respect to the axial direction CL exhibits anisotropy with respect to bending stiffness, there is a risk that the prepreg sheet 10 may bend in an unintended direction during step S12 in the first step S1. As in this example, forming multiple prepreg sheets 10A and 10B with different orientation angles of the fibers 2 by stacking them is desirable because it mitigates the anisotropy of the prepreg sheet and helps to efficiently obtain a primary processed member 11 that is curved to the desired shape.
[0051] [Modified example of a molding die for a primary processed component] Figure 17 is a perspective view showing another example of a mold used in the first step S1. In the embodiments described above, multiple types of molds 21 with different radii of curvature of the molding surface 20 were used, as shown in Figures 8 to 11. Alternatively, a mold 21A as shown in Figure 17 may be used.
[0052] The mold 21A includes a first portion 211 in which the radius of curvature of the molding surface 20 gradually decreases toward one side in the axial direction. Alternatively, the mold 21A may include, for example, the first portion 211 and a second portion 212 in which the radius of curvature of the molding surface 20 is constant in the axial direction. The second portion 212 is connected to the smaller diameter side of the first portion 211, and each molding surface 20 is axially continuous within the mold 21A.
[0053] When forming the primary processed member 11 using this mold 21A, first, a prepreg sheet 10 is prepared that is approximately the same length as or shorter than the axial length of the first part 211 and placed in the first part 211. In the first part 211, the prepreg sheet 10 is heated and softened, and formed along the molding surface 20 of the first part 211 (into a tapered, roughly tubular shape). Next, the formed prepreg sheet 10 is gradually moved to the second part 212 and cooled, so that the prepreg sheet 10 can be curved to a substantially constant and small outer diameter using a single mold.
[0054] Although the mold 21A shown in Figure 17 has a second portion 212, the mold 21A may also be formed using only the first portion 211. In this case, a tapered primary processed member 11 can be formed.
[0055] Although several embodiments of the present invention have been described in detail above, the present invention is not limited to the specific disclosures described above, and can be implemented with various modifications within the scope of the technical idea described in the claims. Furthermore, the present invention includes its equivalents. [Examples]
[0056] Next, more specific and non-limiting embodiments of the present invention will be described. First, twelve prepreg sheets s1 to s12 were prepared based on the specifications in Table 1.
[0057] [Table 1]
[0058] In this example, the prepreg sheet is made by impregnating carbon fibers with an uncured thermoplastic resin (phenoxy resin). This prepreg sheet has low drape properties, meaning it has no tackiness and cannot be bent into an arc shape at room temperature. The dimensions of the prepreg sheet were rectangular, with a width of approximately 50 mm and an axial length of approximately 400 mm. In Table 1, the orientation angle of the carbon fibers indicates the angle with respect to the axial direction of the tubular body.
[0059] Next, as shown in Table 1, two adjacent prepreg sheets (for example, sets s1 and s2) were stacked on top of each other, and then covered with a release sheet to prepare a laminated prepreg sheet.
[0060] Next, the laminated prepreg sheet was inserted into a tubular mold with an inner diameter of 55 mm and heated at 200°C for 3 minutes. This heating softened the laminated prepreg sheet, causing it to deform under its own weight to conform to the molding surface of the mold. The laminated prepreg sheet was then cooled to room temperature. After cooling, the laminated prepreg sheet was removed from the mold and, in its free state, retained its curved shape.
[0061] Next, the curved laminated prepreg sheet was inserted into a tubular mold with an inner diameter of 45 mm and heated again at 200°C for 3 minutes. This heating caused the laminated prepreg sheet to soften again and deform under its own weight to conform to the molding surface of the mold. After that, the laminated prepreg sheet was cooled to room temperature. After cooling, the laminated prepreg sheet was removed from the mold and retained its curved shape in its free state.
[0062] The above process was repeated while gradually decreasing the inner diameter of the mold to 38mm, 32mm, 28mm, 25mm, 22mm, 20mm, 18mm, and 16mm. This resulted in the first primary processed component, in which two prepreg sheets s1 and s2 were integrated. The same process was also performed for all the laminated prepreg sheet sets s3+s4, s5+s6, s7+s8, s9+s10, and s11+s12. This resulted in a total of six primary processed components.
[0063] Next, all six primary processed components were attached to the outside of the PFA tube to obtain a prepreg laminate. In this process, the overlapping portions of each primary processed component were attached so that they were in different positions in the circumferential direction.
[0064] Next, the prepreg laminate was placed in the mold along with the tube and heated at 260°C for 30 minutes. The inner diameter of the mold was 15.75 mm. The tube was also inflated, pressing the outer surface of the prepreg laminate against the molding surface of the mold. After 30 minutes of heating, the prepreg laminate was cooled to room temperature, and the tubular body was removed from the mold.
[0065] Figure 18 shows a cross-section of the manufactured tubular body. As is clear from Figure 18, the manufacturing method of the tubular body in this embodiment makes it possible to easily form a cylindrical laminate using a prepreg sheet with low tack and / or drape properties, and to manufacture a tubular body that does not contain voids or the like inside.
[0066] [Note] The present invention includes the following embodiments. [Invention 1] A method for manufacturing a tubular body, A first step of obtaining a substantially tubular primary processed member from at least one prepreg sheet containing fibers and resin, A second step involves stacking multiple of the aforementioned primary processed members to obtain a prepreg laminate, The process includes a third step of obtaining a tubular body by heat molding the prepreg laminate, The primary processed member comprises a first edge and a second edge that extend in the axial direction of a substantially tubular shape, The first edge and the second edge are each considered free ends. A method for manufacturing tubular bodies. [2nd Invention] The method for producing a tubular body according to Invention 1, wherein the resin is a thermoplastic resin. [Invention 3] The aforementioned primary processed member is substantially cylindrical in shape. The method for manufacturing a tubular body according to invention 1 or 2, wherein the primary processed member includes a first primary processed member in which the circumferential angle from the first edge to the second edge exceeds 360 degrees. [4th Invention] The aforementioned primary processed member is substantially cylindrical in shape. The method for manufacturing a tubular body according to invention 1 or 2, wherein the primary processed member includes a second primary processed member in which the circumferential angle from the first edge to the second edge is less than 360 degrees. [5th Invention] The aforementioned first step includes a primary processing step, The aforementioned primary processing step is: A step of placing the prepreg sheet inside a mold having a curved molding surface, A step of softening the prepreg sheet by heating and deforming it to conform to the molding surface, A method for manufacturing a tubular body according to the present invention 1, comprising the steps of cooling the deformed prepreg sheet and then removing it from the mold. [Invention 6] The method for manufacturing a tubular body according to the present invention, wherein the primary processing step is repeated multiple times while reducing the radius of curvature of the molded surface. [7th Invention] The method for manufacturing a tubular body according to the present invention, wherein the mold has a hollow pipe shape in which the molded surface is cylindrical. [8th Invention] The method for manufacturing a tubular body according to the present invention, wherein the molded surface includes a portion in which the radius of curvature is constant in the axial direction. [Invention 9] The method for manufacturing a tubular body according to the present invention, wherein the molded surface includes a portion in which the radius of curvature gradually decreases toward one side in the axial direction. [Invention 10] The method for manufacturing a tubular body according to invention 1 or 2, wherein the at least one prepreg sheet includes a laminated prepreg sheet obtained by stacking multiple prepreg sheets with different fiber orientation angles. [Invention 11] The method for manufacturing a tubular body according to the present invention 1 or 2, wherein the second step is to form the prepreg laminate such that the first edge and the second edge of a plurality of the primary processed members are at different positions in the circumferential direction. [Invention 12] The method for manufacturing a tubular body according to the present invention 1 or 2, wherein the third step includes a step of pressurizing the inside of the prepreg laminate and pressing the outer surface of the prepreg laminate against the molding surface of a mold. [13th Invention] It is a tubular body, A tubular body comprising a cured laminate of a plurality of primary processed members, each of which at least one prepreg sheet containing fibers and a thermoplastic resin is formed into a substantially tubular shape. [Explanation of Symbols]
[0067] 1. Tubular body 2 Fibers 10 prepreg sheets 10A Prepreg Sheet 10B Prepreg Sheet 11 Primary processed component 11A First primary processed member 11B Second primary processed member 11a First Edge 11b Second Edge 20 Molding surface 21, 21A type 30 prepreg laminates 50 molds
Claims
1. A method for manufacturing a tubular body, A first step of obtaining a primary processed member from at least one prepreg sheet containing fibers and resin, A second step involves stacking multiple of the aforementioned primary processed members to obtain a prepreg laminate, The process includes a third step of obtaining a tubular body by heat molding the prepreg laminate, The primary processed member comprises a first edge and a second edge extending in the axial direction, The primary processed member is curled into a tubular shape overall, but is not a completely closed tube in the circumferential direction, and is substantially circular in shape with a circumferential angle of 225 degrees or more from the first edge to the second edge. In the state in which the prepreg laminate is formed, the first edge and the second edge of each primary processed member are set as free ends. The primary processed member includes a first primary processed member in which the circumferential angle from the first edge to the second edge exceeds 360 degrees. A method for manufacturing tubular bodies.
2. The method for producing a tubular body according to claim 1, wherein the resin is a thermoplastic resin.
3. The method for manufacturing a tubular body according to claim 1 or 2, wherein the primary processed member includes a second primary processed member in which the circumferential angle from the first edge to the second edge is less than 360 degrees.
4. The first step includes a primary processing step, The aforementioned primary processing step is A step of placing the prepreg sheet inside a mold having a curved molding surface, A step of softening the prepreg sheet by heating and deforming it to conform to the molding surface, A method for manufacturing a tubular body according to claim 1, comprising the steps of cooling the deformed prepreg sheet and then removing it from the mold.
5. The method for manufacturing a tubular body according to Claim 4, wherein the primary processing step is repeated multiple times while reducing the radius of curvature of the molded surface.
6. The method for manufacturing a tubular body according to claim 4 or 5, wherein the mold has a cylindrical shape in which the molding surface is cylindrical.
7. The method for manufacturing a tubular body according to claim 6, wherein the molded surface includes a portion in which the radius of curvature is constant in the axial direction.
8. The method for manufacturing a tubular body according to claim 6, wherein the molded surface includes a portion in which the radius of curvature gradually decreases toward one side in the axial direction.
9. The method for manufacturing a tubular body according to claim 1 or 2, wherein the at least one prepreg sheet includes a laminated prepreg sheet obtained by stacking a plurality of prepreg sheets having different fiber orientation angles.
10. The method for manufacturing a tubular body according to claim 1 or 2, wherein the second step is to form the prepreg laminate such that the first edge and the second edge of the plurality of primary processed members are at different positions in the circumferential direction.
11. The method for manufacturing a tubular body according to claim 1 or 2, wherein the third step includes pressing the inside of the prepreg laminate and pressing the outer surface of the prepreg laminate against the molding surface of a mold.
12. A method for manufacturing a tubular body, A first step of obtaining a primary processed member from at least one prepreg sheet containing fibers and resin, A second step involves stacking multiple of the aforementioned primary processed members to obtain a prepreg laminate, The process includes a third step of obtaining a tubular body by heat molding the prepreg laminate, The primary processed member comprises a first edge and a second edge extending in the axial direction, The primary processed member is curled in a tubular shape overall, but is not a completely closed tube in the circumferential direction, and is substantially tubular in shape with a circumferential angle of 225 degrees or more from the first edge to the second edge. In the state in which the prepreg laminate is formed, the first edge and the second edge of each primary processed member are set as free ends. The first step includes a primary processing step, and the primary processing step is A step of placing the prepreg sheet inside a mold having a curved molding surface, A step of softening the prepreg sheet by heating and deforming it to conform to the molding surface, The process includes the step of cooling the deformed prepreg sheet and then removing it from the mold, A method for manufacturing tubular bodies.
13. A method for manufacturing a tubular body, A first step of obtaining a primary processed member from at least one prepreg sheet containing fibers and resin, A second step involves stacking multiple of the aforementioned primary processed members to obtain a prepreg laminate, The process includes a third step of obtaining a tubular body by heat molding the prepreg laminate, The primary processed member comprises a first edge and a second edge extending in the axial direction, The primary processed member is curled in a tubular shape overall, but is not a completely closed tube in the circumferential direction, and is substantially tubular in shape with a circumferential angle of 225 degrees or more from the first edge to the second edge. In the state in which the prepreg laminate is formed, the first edge and the second edge of each primary processed member are set as free ends. The at least one prepreg sheet includes a laminated prepreg sheet formed by stacking multiple prepreg sheets with different fiber orientation angles. A method for manufacturing tubular bodies.