JP7783044B2 - Method for manufacturing fiber-reinforced resin structural members - Google Patents

Description

This disclosure relates to a method for manufacturing a fiber-reinforced resin structural member.

In recent years, with the aim of reducing the weight of vehicle bodies, there has been research into manufacturing the structural components that make up the vehicle body using fiber-reinforced resins containing reinforcing fibers such as carbon fiber (see, for example, Patent Document 1).

JP 2013-193637 A

When bolting a structural member made of fiber-reinforced resin to another member, precision in the shape and position of the mounting surface is required to increase connection accuracy. In response to this, for example, by molding the surface formed by the molding die as the mounting surface, it is possible to ensure the precision of the mounting surface is equivalent to the precision of the molding die's surface. However, when using this manufacturing method, it is necessary to join a nut plate for bolting to the surface opposite the mounting surface after molding the molded body.

Furthermore, when the surface opposite the mounting surface is molded as a surface to be molded using a mold, one option is to control the mounting surface by performing NC (numerical control) processing such as grinding or cutting on the mounting surface after molding to ensure precision in its shape and position. However, grinding or cutting a fiber-reinforced resin molded product can cut the fibers, potentially reducing the strength and rigidity of the structural member. Even when using this manufacturing method, it is still necessary to join a nut plate for bolt tightening to the surface opposite the mounting surface after molding.

This disclosure has been made in light of the above problems, and its purpose is to provide a simple manufacturing method for structural components that ensures the accuracy of the shape of the mounting surface where the component is to be bolted to another component.

In order to solve the above-mentioned problems, according to one aspect of the present disclosure, there is provided a method for manufacturing a fiber-reinforced resin structural member having a connection part including a hole for inserting a fastening member, the method comprising the steps of: forming an uncured fiber-reinforced resin layer containing an uncured matrix resin and reinforcing fibers on the molding surface of a jig; curing the matrix resin to form a fiber-reinforced resin structural member; and removing the jig from the fiber-reinforced resin structural member. In the step of forming the uncured fiber-reinforced resin layer, a metal insert having a hole or a location where the hole is to be formed is embedded in the uncured fiber-reinforced resin layer so that a portion of the metal insert contacts the jig and the hole or the location where the hole is to be formed is exposed on an outer surface of the uncured fiber-reinforced resin layer that does not contact the jig.

As explained above, this disclosure makes it possible to easily manufacture structural components that ensure the accuracy of the shape of the mounting surface where the component is intended to be bolted to another component.

1 is a cross-sectional view of a joined structure including a fiber-reinforced resin structural member obtained by a manufacturing method according to an embodiment of the present disclosure. 3 is an explanatory view showing a metal insert used in the structural member according to the embodiment; FIG. 1A to 1C are explanatory diagrams showing a manufacturing method of a first reference example. 10A to 10C are explanatory diagrams showing a manufacturing method of a second reference example. 10 is an explanatory view showing a state in which a metal insert is placed on a jig in the manufacturing method of a structural member according to the embodiment. FIG. 4 is an explanatory diagram showing a state in which first fiber-reinforced resin sheets are stacked in the manufacturing method of a structural member according to the embodiment. FIG. 10 is an explanatory view showing a state in which a second fiber-reinforced resin sheet is laminated in the manufacturing method of the structural member according to the embodiment. FIG. 4 is an explanatory view showing a state in which an uncured fiber reinforced resin layer is formed in the manufacturing method of the structural member according to the embodiment. FIG. 3 is an explanatory diagram showing a structural member manufactured by the manufacturing method of a structural member according to the embodiment; FIG. 10A and 10B are explanatory diagrams showing a modified example of the lamination method of the fiber reinforced resin sheet according to the embodiment. 10 is an explanatory view showing another example of a metal insert used in the structural member according to the embodiment. FIG. 10A and 10B are explanatory views showing a manufacturing method using another example of a metal insert. 10A and 10B are explanatory views showing a manufacturing method using another example of a metal insert. 10A and 10B are explanatory views showing a manufacturing method using another example of a metal insert. FIG. 1 is an explanatory diagram showing a manufacturing method using a filament winding method.

Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. Note that in this specification and drawings, components having substantially the same functional configuration will be assigned the same reference numerals, and redundant explanations will be omitted.

<1. Explanation of fiber-reinforced resin structural members>
First, a fiber-reinforced resin structural member obtained by the method for producing a fiber-reinforced resin structural member according to the present disclosure will be described.

Figure 1 shows a cross-sectional view of a joined structure including a fiber-reinforced resin structural member (hereinafter simply referred to as "structural member") 10 obtained by a manufacturing method according to an embodiment of the present disclosure. The structural member 10 shown in Figure 1 has a hollow cylindrical portion, and its cross-sectional shape is a continuous closed cross-sectional shape around the entire circumference. The structural member 10 has a connection portion 9 including a hole 11a into which a fastening member 5 is inserted, and is joined to another member 3 at the connection portion 9. Specifically, the structural member 10 and the other member 3 are joined by a fastening member (bolt) 5 and a nut 7 inserted so as to pass through the insertion hole 3a provided in the other member 3 and the hole 11a provided in the connection portion 9 of the structural member 10.

The structural member 10 is composed of a fiber-reinforced resin laminate 13 and a metal insert 11. Examples of reinforcing fibers include carbon fiber, but other fibers may also be used, and multiple fibers may also be combined. However, because carbon fiber has excellent mechanical properties, it is preferable that the reinforcing fibers include carbon fiber.

The matrix resin of the fiber-reinforced resin is a thermoplastic resin or a thermosetting resin. Examples of thermoplastic resins include polyethylene resin, polypropylene resin, polyvinyl chloride resin, ABS resin (acrylonitrile-butadiene-styrene copolymer synthetic resin), polystyrene resin, AS resin (acrylonitrile-styrene copolymer synthetic resin), polyamide resin, polyacetal resin, polycarbonate resin, polyester resin, PPS (polyphenylene sulfide) resin, fluororesin, polyetherimide resin, polyetherketone resin, and polyimide resin.

The matrix resin can be one of these thermoplastic resins, or a mixture of two or more of them. Alternatively, the matrix resin can be a copolymer of these thermoplastic resins. When the thermoplastic resin is a mixture, a compatibilizer may be used in combination. Furthermore, a flame retardant such as a bromine-based flame retardant, a silicon-based flame retardant, or red phosphorus may be added to the thermoplastic resin.

Examples of thermosetting resins include epoxy resins, unsaturated polyester resins, vinyl ester resins, phenolic resins, polyurethane resins, and silicone resins. One or a mixture of two or more of these thermosetting resins can be used as the matrix resin. When using these thermosetting resins, an appropriate curing agent or reaction accelerator may be added to the thermosetting resin.

The other member 3 is not particularly limited, and may be a member made of a fiber-reinforced resin composite material, or a metal member such as a steel plate. The other member 3 may also be a structural member manufactured using the manufacturing method disclosed herein.

When joining a fiber-reinforced resin structural member 10 to another member 3, if the shape and position of the attachment surface are not precise, the joint strength may be reduced or the resulting joined structure may deviate from the designed dimensions. To address this, the connecting portion 9 of the structural member 10 disclosed herein is provided with a metal insert 11 having a hole 11a. The metal insert 11 prevents the thickness of the connecting portion 9 from deviating from the designed value and functions to ensure the precision of the shape and position of the attachment surface of the other member 3.

Figure 2 is an explanatory diagram showing the metal insert 11 used in the structural member 10 shown in Figure 1. Figure 2 shows a front view and a side view of the metal insert 11. The metal insert 11 has a conical shape with flat surfaces on both axial ends, and a hole 11a is provided along the axis. Of the flat surfaces on both ends of the metal insert 11, the end face with the larger diameter is located on the inside of the structural member 10. Furthermore, of the flat surfaces on both ends of the metal insert 11, the end face with the smaller diameter is located on the outside of the structural member 10.

By providing metal inserts 11 embedded and exposed on both the inside and outside of the structural member 10 at the connection portion 9, the thickness of the connection portion 9 can be set to the desired design value. Furthermore, the metal inserts 11 can prevent variations in the shape of the mounting surface due to manufacturing conditions, etc., and therefore prevent a decrease in the accuracy of the shape and position of the mounting surface.

Furthermore, because the metal insert 11 has a shape in which the diameter decreases from the inside to the outside of the structural member 10, the contact area between the metal insert 11 and the fiber-reinforced resin laminate 13 is increased, thereby increasing the bonding strength between the metal insert 11 and the fiber-reinforced resin laminate 13. Furthermore, because the metal insert 11 has this shape, it is possible to prevent the metal insert 11 from detaching from the fiber-reinforced resin laminate 13 even if a load is applied to another member 3 in a direction away from the structural member 10.

<2. Manufacturing method according to reference example>
Next, before describing a method for manufacturing a fiber-reinforced resin structural member 10 according to the present disclosure, a method for manufacturing a fiber-reinforced resin structural member according to a reference example will be described.

Figure 3 is an explanatory diagram showing a manufacturing method of the first reference example in which a fiber-reinforced resin laminate 101 is molded around a molding jig 109 and then a nut plate 107 is attached. In the manufacturing method of the first reference example, a fiber-reinforced resin sheet (prepreg) is laid up around the molding jig 109, the fiber-reinforced resin is cured, and then the molding jig 109 is removed to mold the fiber-reinforced resin laminate 101.

After the fiber-reinforced resin laminate 101 is molded, the nut plate 107 is aligned with the inner circumferential surface of the fiber-reinforced resin laminate 101 and bonded, for example, with an adhesive. After that, or before bonding the nut plate 107, a hole 102 is formed into which a fastening member is inserted. In this case, in the manufacturing method of the first reference example, the mounting surface 105 to which another component is bonded is the surface opposite the molding surface 103 formed by the molding jig 109. For this reason, to ensure the accuracy of the shape and position of the mounting surface 105 to which the other component is bonded, NC processing such as grinding or polishing is performed using the jig 108.

As such, the manufacturing method of the first reference example requires, after molding the fiber-reinforced resin laminate 101, the steps of aligning and joining the nut plate 107 to the inner surface of the fiber-reinforced resin laminate 101 and forming the hole 102. Additionally, NC machining is required to ensure the precision of the mounting surface 105, making the manufacturing method complicated. Furthermore, there is a risk that the fibers may be cut when NC machining is performed on the mounting surface 105, which could result in a decrease in the strength or rigidity of the fiber-reinforced resin laminate 101.

Figure 4 is an explanatory diagram showing a second reference example manufacturing method in which two separately molded fiber-reinforced resin laminate halves 111, 117 are joined to form the fiber-reinforced resin laminate 110, and then a nut plate 125 is attached. In the second reference example manufacturing method, fiber-reinforced resin sheets (prepregs) are laminated on the molding surfaces inside the molding dies 121, 123, respectively, and the fiber-reinforced resin is cured. After that, the fiber-reinforced resin laminate halves 111, 117 detached from the molding dies 121, 123 are joined to form the fiber-reinforced resin laminate 110.

After forming the fiber-reinforced resin laminate 110, the nut plate 125 is aligned with the inner circumferential surface of the fiber-reinforced resin laminate 110 and bonded, for example, with an adhesive. After that, or before bonding the nut plate 125, a hole 112 is formed into which a fastening member is inserted.

As such, the manufacturing method of the second reference example requires, after forming the fiber-reinforced resin laminate 110, a process of aligning and joining the nut plate 125 to the inner surface of the fiber-reinforced resin laminate 110, and a process of forming the hole 112, making the manufacturing method more complicated.

3. Manufacturing method according to the present disclosure
Next, a method for manufacturing a fiber-reinforced resin structural member 10 according to an embodiment of the present disclosure will be described. In this embodiment, a fiber-reinforced resin sheet (prepreg) is laminated on the surface of a jig. In the following description, the larger surface of the flat surfaces at both ends of the metal insert 11 shown in FIG. 2 will be referred to as the lower surface, and the smaller surface will be referred to as the upper surface.

Figures 5 to 9 are explanatory diagrams showing a manufacturing method for a structural member 10 according to this embodiment. Each figure shows a cross-sectional view including a portion corresponding to the connection portion 9 of the structural member 10, and a plan view of the portion corresponding to the connection portion 9 as seen from the outside.

As shown in Figure 5, a jig 21 corresponding to the three-dimensional shape of the cylindrical fiber-reinforced resin laminate to be molded is prepared, and the metal insert 11 shown in Figure 2 is fixed so that its underside contacts the jig 21. Even when aligning the placement position of the metal insert 11 at this time, this can be done relatively easily because it is alignment when placing it on the outer peripheral surface of the jig 21. The metal insert 11 is fixed to the jig 21 by any appropriate means that allows it to be easily fixed to the jig 21.

Next, as shown in FIG. 6, the uncured first fiber-reinforced resin sheet 15a is wrapped around the jig 21 and stacked. At this time, at the position of the metal insert 11, the metal insert 11 is exposed from between the continuous fibers so that the fibers do not hang over at least the hole 11a of the metal insert 11. An opening is formed in the first fiber-reinforced resin sheet 15a to accommodate the metal insert 11. The opening may be pre-formed in the first fiber-reinforced resin sheet 15a, or may be formed by widening the gaps between the continuous fibers when stacking the first fiber-reinforced resin sheets 15a. The first fiber-reinforced resin sheet 15a is stacked so that at least a portion of the edge of the opening covers part or all of the outer periphery of the metal insert 11.

Furthermore, as shown in FIG. 7, an uncured second fiber-reinforced resin sheet 15b is further wrapped around and laminated on the first fiber-reinforced resin sheet 15a. At this time, at the position of the metal insert 11, the metal insert 11 is exposed from the surface between the continuous fibers so that the fibers do not hang over at least the hole 11a of the metal insert 11. Similarly, an opening is formed in the second fiber-reinforced resin sheet 15b in which the metal insert 11 is placed. Furthermore, the second fiber-reinforced resin sheet 15b is laminated so that at least a portion of the edge of the opening covers part or all of the outer periphery of the metal insert 11.

The metal inserts 11 fixed to the jig 21 have a shape in which the diameter decreases from the jig 21 toward the outside. Therefore, when wrapping each fiber-reinforced resin sheet, the metal inserts 11 are pressed against the jig 21 with the top surface of the metal inserts 11 exposed through the gaps between the continuous fibers, which makes it easier for the continuous fibers to slip along the inclined surface of the metal inserts 11. Note that the orientation direction of the continuous fibers in the fiber-reinforced resin sheets shown in Figures 6 and 7 is an example, and the orientation direction of the continuous fibers is not particularly limited.

In this manner, an appropriate number of fiber-reinforced resin sheets are repeatedly stacked, and the uncured fiber-reinforced resin layer 15 is formed by embedding the metal insert 11 in the fiber-reinforced resin layer 15 so that the top surface of the metal insert 11, including the hole 11a, is exposed on the outer surface of the fiber-reinforced resin layer 15, as shown in Figure 8. At this time, the continuous fibers contained in the uncured fiber-reinforced resin layer 15 are arranged uninterruptedly around the top surface of the metal insert 11. Furthermore, by stacking the fiber-reinforced resin sheets so that the orientation direction of the continuous fibers contained in the sheets is crossed, or by using a fiber-reinforced resin sheet (cross material) containing continuous fibers oriented in multiple directions, the metal insert 11 can be held down by the continuous fibers so that it surrounds the top surface of the metal insert 11.

Next, the uncured fiber-reinforced resin layer 15 laminated on the jig 21 is cured, and then the jig 21 is removed to obtain the fiber-reinforced resin structural member 10 as shown in Figure 9.

This allows the metal insert 11 and fiber-reinforced resin laminate 13 to be bonded over a relatively large area, resulting in the production of a structural member 10 in which the area around the hole 11a, which serves as the connection 9 with another member, is strongly reinforced with continuous fibers. Furthermore, because the thickness of the structural member 10 at the connection 9 is determined by the metal insert 11, the positioning accuracy of the connection 9 can be improved. Furthermore, because the top surface of the metal insert 11 is exposed at the connection 9 with the other member, the accuracy of the shape of the attachment surface with the other member can be ensured.

When stacking fiber-reinforced resin sheets while embedding the metal insert 11, multiple fiber-reinforced resin sheets may be stacked so that one fiber-reinforced resin sheet contacts the surface of the metal insert 11 facing the jig 21 or the surface opposite the jig 21.

Figure 10 shows an example in which the first fiber-reinforced resin sheet 15c to be laminated first on the jig 21 is positioned so that it contacts the metal insert 11, and subsequent fiber-reinforced resin sheets are not in contact with the metal insert 11, forming the fiber-reinforced resin layer 15. By laminating in this manner, the bonding strength between the metal insert 11 and the fiber-reinforced resin laminate 13 of the structural member 10 obtained by curing the fiber-reinforced resin layer 15 can be increased.

Furthermore, the shape of the metal insert is not limited to the example shown in Figure 2. The metal insert can have any shape as long as a portion of it comes into contact with the jig 21 during the manufacturing of the structural member, the upper surface on which the hole 11a is formed can be exposed to the outer surface when the uncured fiber-reinforced resin layer is laminated, and it can be embedded in the uncured fiber-reinforced resin layer.

Figure 11 is an explanatory diagram showing another example configuration of a metal insert. Figure 11 shows a front view and a side view of a metal insert 31. The metal insert 31 has flat surfaces on both axial ends, a large diameter in the axial center, and a diameter that decreases toward both axial ends. The metal insert 31 has a hole 31a formed along the axis. Because the metal insert 31 has a shape in which the diameter decreases toward both axial ends, the contact area between the metal insert 31 and the fiber-reinforced resin laminate 13 is increased, thereby increasing the bonding strength between the metal insert 11 and the fiber-reinforced resin laminate 13. Furthermore, because the metal insert 31 has the same shape, fiber-reinforced resin sheets can be stacked so as to sandwich the metal insert 31. This prevents the metal insert 31 from detaching from the fiber-reinforced resin laminate 13 even when a load is applied to the structural member 10 from another member 3.

12 to 14 are explanatory views showing a method for manufacturing a structural member provided with the metal insert 31 shown in FIG.
When using metal inserts 31, first, as shown in Fig. 12, a plurality of fiber-reinforced resin sheets 15d, each having an opening 16 in which a metal insert 31 is to be placed, are stacked on the molding surface of a jig 21. The openings 16 may be provided in the fiber-reinforced resin sheets 15d in advance, or may be formed by widening the gaps between the continuous fibers when stacking the fiber-reinforced resin sheets 15d. In this case, too, by forming the openings 16 without interrupting the continuous fibers contained in the fiber-reinforced resin sheets 15d, it is possible to prevent a decrease in the strength or rigidity of the structural member.

Next, as shown in FIG. 13, the metal insert 31 is placed in the opening 16 of the fiber-reinforced resin sheet 15d so that a portion of the metal insert 31 contacts the jig 21 and at least a portion of the outer edge of the metal insert 31 covers the edge of the opening 16 in the fiber-reinforced resin sheet 15d.

Next, as shown in FIG. 14, multiple fiber-reinforced resin sheets 15d, each having an opening in which a metal insert 31 is placed, are stacked so that at least part of the edge of the opening covers part of the metal insert 31. These openings may also be provided in the fiber-reinforced resin sheets 15d in advance, or may be formed by widening the gaps between the continuous fibers when stacking the fiber-reinforced resin sheets 15d.

As a result, the top surface of the metal insert 31, which has the hole 31a in the center, is exposed to the outside, while the area surrounding the center is sandwiched between the fiber-reinforced resin layers 15. This increases the bonding strength of the metal insert 31, resulting in a structural member with improved strength at the connection with other members. Furthermore, even with this metal insert 31, the thickness and shape of the structural member at the connection can be manufactured to the desired design values, improving the precision of the shape and position of the connection with other members.

Furthermore, the method for forming the uncured fiber-reinforced resin layer on the molding surface of the jig 21 is not limited to the layup method described in the above embodiment, and any method may be used. For example, if the structural member is a hollow cylindrical structural member, the uncured fiber-reinforced resin layer may be formed using a filament winding method, in which continuous fibers are continuously wound around the jig 21.

Figure 15 is an explanatory diagram showing continuous fiber wound around a jig 21 using the filament winding method. Even when using the filament winding method, after placing the metal insert 11 in a predetermined position on the jig 21, continuous fiber impregnated with matrix resin is drawn out from around the jig 21, and the jig 21 or the mechanism for drawing out the continuous fiber is rotated and moved axially to form an uncured fiber-reinforced resin layer 17 around the jig 21. Even in this case, the metal insert 11 has a shape in which the diameter decreases outward from the jig 21 side, making it easier to wind the continuous fiber without it touching the top surface of the metal insert 11.

As a result, the top surface of the metal insert 11 is exposed between the continuous fibers, which increases the accuracy of the connection position and ensures the accuracy of the shape of the attachment surface with other components. Furthermore, even with the filament winding method, the metal insert 11 can be held down with continuous fibers, surrounding the periphery of its top surface. Therefore, even if a load is applied to other components in a direction away from the structural member, the metal insert 11 can be prevented from detaching from the fiber-reinforced resin laminate.

As described above, according to the manufacturing method of a fiber-reinforced resin structural member of this embodiment, a metal insert 11 having a hole 11a is placed on the molding surface of the jig 21 at a position corresponding to the connection with another member, and the fiber-reinforced resin layer is formed by embedding the metal insert 11 in the uncured fiber-reinforced resin layer so that the hole 11a is exposed on the outer surface of the uncured fiber-reinforced resin layer. This eliminates the need to attach a nut plate to the inside of the cylindrical fiber-reinforced resin laminate after forming the fiber-reinforced resin laminate.

Furthermore, in structural components manufactured using the manufacturing method of this embodiment, the connection portions with other components are controlled to the desired design values by the metal insert 11. This ensures the accuracy of the shape and position of the mounting surface of other components.

Preferred embodiments of the present disclosure have been described in detail above with reference to the accompanying drawings, but the present disclosure is not limited to these examples. It is clear that a person with ordinary skill in the technical field to which the present disclosure pertains can conceive of various modified or altered examples within the scope of the technical ideas set forth in the claims, and it is understood that these naturally fall within the technical scope of the present disclosure. Furthermore, combinations of the above-described embodiments and modifications naturally fall within the technical scope of the present disclosure.

For example, in the above embodiment, a metal insert 11 was used with a hole 11a already formed therein. However, holes into which fastening members for attaching other components can be inserted may be formed after the structural component is molded. In this case, the uncured fiber-reinforced resin layer can be formed so that the locations in the metal insert where the holes are to be formed are exposed on the outer surface.

5: Fastening member, 9: Connection, 10: Fiber-reinforced resin structural member, 11: Metal insert, 11a: Hole, 13: Fiber-reinforced resin laminate, 15: Fiber-reinforced resin layer, 15a: First fiber-reinforced resin sheet, 15b: Second fiber-reinforced resin sheet, 16: Opening, 21: Jig

Claims (5)

A method for manufacturing a fiber-reinforced resin structural member having a connection portion including a hole portion into which a fastening member is inserted, comprising:
forming an uncured fiber reinforced resin layer containing an uncured matrix resin and reinforced fibers on a molding surface of a jig;
a step of curing the matrix resin to form the fiber-reinforced resin structural member;
and removing the jig from the fiber-reinforced resin structural member,
In the step of forming the uncured fiber reinforced resin layer,
A method for manufacturing a fiber-reinforced resin structural member , comprising: embedding a metal insert having the hole portion or a location where the hole portion is to be formed, the metal insert having a cone-shaped portion whose diameter decreases in a direction from the jig side to away from the jig, into the uncured fiber-reinforced resin layer so that a portion of the metal insert contacts the jig and the hole portion or the location where the hole portion is to be formed is exposed on an outer surface of the uncured fiber-reinforced resin layer that does not contact the jig. the metal insert has a conical shape with a maximum diameter at a portion in contact with the jig and a minimum diameter at a portion farthest from the jig;
In the step of forming the uncured fiber reinforced resin layer,
After the metal insert is placed on the molding surface of the jig,
2. A method for manufacturing a fiber-reinforced resin structural member according to claim 1, wherein a plurality of fiber-reinforced resin sheets, each having an opening in which the metal insert is placed, are stacked so that at least a portion of the edge of the opening covers the inclined surface of the conical metal insert. A method for manufacturing a fiber-reinforced resin structural member having a connection portion including a hole portion into which a fastening member is inserted, comprising:
forming an uncured fiber reinforced resin layer containing an uncured matrix resin and reinforced fibers on a molding surface of a jig;
a step of curing the matrix resin to form the fiber-reinforced resin structural member;
and removing the jig from the fiber-reinforced resin structural member,
In the step of forming the uncured fiber reinforced resin layer,
A metal insert having the hole portion or a planned location for forming the hole portion, wherein the diameter of the first cone-shaped portion is maximum at the axial center and the diameter decreases toward the jig in the axial direction, and a second cone-shaped portion having a diameter decreasing toward the jig in the axial direction. A plurality of fiber-reinforced resin sheets each having an opening in which the metal insert having the metal insert is placed are stacked on the molding surface of the jig,
The metal insert is placed in the opening of the fiber reinforced resin sheet so that a portion of the metal insert contacts the jig, the hole or the planned formation location of the hole is exposed on an outer surface of the uncured fiber reinforced resin layer that does not contact the jig, and the inclined surface of the first cone-shaped portion of the metal insert covers the edge of the opening of the fiber reinforced resin sheet,
A method for manufacturing a fiber-reinforced resin structural member further comprising stacking a plurality of fiber-reinforced resin sheets, each having an opening into which the metal insert is placed, so that at least a portion of the edge of the opening covers the inclined surface of the second cone-shaped portion of the metal insert, thereby forming the uncured fiber-reinforced resin layer. The method for manufacturing a fiber-reinforced resin structural member described in claim 2 or 3, wherein the multiple fiber-reinforced resin sheets are stacked so that one fiber-reinforced resin sheet contacts the jig-side surface or the surface opposite the jig side of the metal insert. the metal insert has a conical shape with a maximum diameter at a portion in contact with the jig and a minimum diameter at a portion farthest from the jig;
The fiber-reinforced resin structural member is a hollow cylindrical structural member,
In the step of forming the uncured fiber reinforced resin layer,
2. The method for manufacturing a fiber-reinforced resin structural member according to claim 1, wherein the metal insert is placed on the molding surface of the jig, and then the uncured fiber-reinforced resin layer is formed by a filament winding method so as to cover the inclined surface of the conical metal insert.