Manufacturing method of the structure

Abstract

To provide a method for manufacturing a structure capable of avoiding trouble in smooth manufacturing of the structure.SOLUTION: A method for manufacturing a structure includes a dropping step, a forming step and a core material placement step. In the dropping step, a molten resin sheet is dropped on a front side of a mold. In the forming step, the dropped resin sheet is formed in a cavity part of the mold. In the core material placement step, the core material is placed on the resin sheet that is formed in the cavity part. The core material is temporarily held in the resin sheet by a separate member that is independent of the core material, and the separate member is bonded to the mold or the core material.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a structure. [Background technology]

[0002] Patent Document 1 discloses a method for manufacturing a structure (molded body) by attaching a core material to a molten resin sheet formed in a mold and then clamping the mold. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-179528 Summary of the Invention [Problem to be solved by the invention]

[0004] The manufacturing method of Patent Document 1 has a problem in that the core material attached to a predetermined position on the molten resin sheet may shift from the predetermined position, which may hinder the smooth manufacturing of the structure.

[0005] The present invention has been made in view of the above circumstances, and aims to provide a method for manufacturing a structure that can avoid any hindrance to the smooth manufacture of the structure. [Means for solving the problem]

[0006] According to the present invention, there is provided a method for manufacturing a structure, the method comprising a hanging step, a shaping step, and a core material placement step, in which in the hanging step, a molten resin sheet is hung down onto the front side of a mold, in the shaping step, the hung resin sheet is shaped into a cavity portion of the mold, and in the core material placement step, a core material is placed on the resin sheet shaped into the cavity portion, and the core material is temporarily held to the resin sheet by a separate member independent of the core material, and the separate member is joined to the mold or the core material.

[0007] According to the present invention, in the core material placement process, the core material is temporarily held in the resin sheet by a mold or a separate member joined to the resin sheet, thereby suppressing misalignment of the core material and avoiding any hindrance to the smooth manufacture of the structure.

[0008] Various embodiments of the present invention will be described below as examples, and the embodiments shown below can be combined with each other. Preferably, the separate member is composed of a protruding member, which is provided on the mold and configured to be able to protrude from the mold side to the resin sheet side, and in the core material placement process, the core material is temporarily held in place on the resin sheet by engaging with the protruding protruding member. Preferably, the method further includes a mold closing step and a degassing step, wherein the protruding member is formed with an air intake port for exhausting air from within the cavity portion, and in the core material positioning step, when the core material is engaged with the protruding member, the air intake port of the protruding member is exposed from the core material, and in the mold closing step, the mold is closed to make the cavity portion a closed space, and in the degassing step, air from within the cavity portion is sucked in through the air intake port of the protruding member and exhausted from within the cavity portion. Preferably, the separate member is a skin material or a welding member, the skin material being made of a fiber material that covers a portion of the surface of the core material, and the welding member being attached to a portion of the surface of the core material and made of a resin that is more easily welded to the resin sheet than the resin that constitutes the core material. Preferably, the resin sheet is made of polypropylene and the core material is made of polystyrene. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 shows an example of a molding machine 1 that can be used in the method for manufacturing a structure according to the first embodiment. [Figure 2] Fig. 2A is a perspective view of the mold device 31 on the left side shown in Fig. 1. Fig. 2B is a vertical cross-sectional view taken at a position passing through the pair of upper and lower holes 32A on the right side shown in Fig. 2A. Fig. 2C shows the protruding member 32B shown in Fig. 2B in a protruding state. Note that the decompression suction hole 33s is not shown in Figs. 2B and 2C. The same applies to the following drawings. [Figure 3] Fig. 3A shows a state in which the suction step is being carried out with the outer frame 33 advanced, and Fig. 3B shows a state in which the outer frame 33 is retracted during the suction step. [Figure 4] Fig. 4A shows a state in which the shaping step is being carried out, and Fig. 4B shows a state in which the core material 3 is being placed between a pair of mold devices 31 in the core material placement step. [Figure 5] Fig. 5A shows a state in which the core material 3 is welded to the resin sheet 23 in the core material arranging step. Fig. 5B shows a state in which the protruding member 32B is pierced into the core material 3 in the core material arranging step. [Figure 6] Fig. 6A shows a state in which the insertion device 19 shown in Fig. 5B has moved away from the core material 3 during the core material placement process. Fig. 6B shows a state in which the mold clamping process is being performed. Fig. 6C is an enlarged view of area C shown in Fig. 6B. [Figure 7]FIG. 7 is a plan view of the core material 3, and is an explanatory diagram of the position where the protruding member 32B is stuck. [Figure 8] FIG. 8 is a cross-sectional view showing a modified example of the protruding member 32B. [Figure 9] Fig. 9A is a cross-sectional view illustrating a method for manufacturing a structure according to the second embodiment, and Fig. 9B is an enlarged view of a region B shown in Fig. 9A. DETAILED DESCRIPTION OF THE INVENTION

[0010] The following describes embodiments with reference to the drawings. The various features shown in the following embodiments can be combined with each other. Furthermore, each feature can be an independent invention.

[0011] 1. First embodiment 1-1. Configuration of molding machine 1 A molding machine 1 used in the manufacturing method of the structure according to the embodiment will be described. As shown in FIG. 1, the molding machine 1 includes a pair of resin sheet forming devices 2, a pair of mold devices 31, and an insertion device 19 (see FIG. 4B). The molding machine 1 is capable of molding a structure 100 as shown in FIG. 6B. This structure 100 has a core material 3 and a resin sheet 23 formed so as to cover the periphery of the core material. The core material 3 can be made of polystyrene. Polystyrene is cheaper than polyethylene. The core material 3 may be made of, for example, polyethylene, or a mixed resin of polystyrene and polyethylene. The core material 3 may be made of, for example, a foam.

[0012] Each resin sheet forming apparatus 2 includes a hopper 12, an extruder 13, an accumulator 17, and a T-die 18. The extruder 13 and the accumulator 17 are connected via a connecting pipe 25. The accumulator 17 and the T-die 18 are connected via a connecting pipe 27.

[0013] <Hopper 12, Extruder 13> The hopper 12 is used to feed the raw resin 11 into the cylinder 13a of the extruder 13. The form of the raw resin 11 is not particularly limited, but is usually pelletized. The raw resin is a thermoplastic resin such as polyolefin. In this embodiment, the polyolefin is polypropylene. However, the polyolefin is not limited thereto, and low-density polyethylene, linear low-density polyethylene, high-density polyethylene, ethylene-propylene copolymer, and mixtures thereof may also be used. The raw resin 11 is fed from the hopper 12 into the cylinder 13a and then heated in the cylinder 13a to melt it into a molten resin. The raw resin 11 is then transported toward the tip of the cylinder 13a by the rotation of a screw disposed in the cylinder 13a. The screw is disposed in the cylinder 13a and kneads and transports the molten resin by its rotation. A gear device is provided at the base end of the screw, and the screw is rotated by the gear device. The number of screws disposed in the cylinder 13a may be one or two or more.

[0014] <Accumulator 17, T-die 18> The molten resin is extruded from the resin extrusion port of the cylinder 13a and injected into the accumulator 17 through the connecting pipe 25. The accumulator 17 includes a cylinder 17a and a piston 17b that can slide inside the cylinder 17a, and the molten resin can be stored in the cylinder 17a. After a predetermined amount of molten resin has been stored in the cylinder 17a, the piston 17b is moved, whereby the molten resin is extruded through the connecting pipe 27 and drooped down from a slit provided in the T-die 18, forming a molten resin sheet 23.

[0015] <Molding device 31> Each mold device 31 includes a mold 32 for molding the resin sheet 23, and an outer frame 33 configured to be movable along the peripheral surface 32s of the mold 32. The mold device 31 on the right side shown in FIG. 1 includes a protruding member 32B (an example of a separate member), while the mold device 31 on the left side does not. Otherwise, the configuration of the mold device 31 on the right side is similar to that of the mold device 31 on the left side. The outer frame 33 is configured to be movable by a cylinder mechanism or the like.

[0016] The mold 32 is substantially rectangular parallelepiped and includes a front surface 32f, a back surface 32r, and a peripheral surface 32s therebetween. The front surface 32f faces the resin sheet 23, and the back surface 32r faces opposite the front surface 32f. The peripheral surface 32s includes a top surface 32st, a bottom surface 32sb, a side surface 32sr, and a side surface 32sl. The top surface 32st and the bottom surface 32sb face each other, and the side surfaces 32sr and 32sl face each other.

[0017] The mold 32 has a cavity portion 32a, and a pinch-off portion 32b is provided to surround the cavity portion 32a. A vacuum suction hole (not shown) is provided inside the cavity portion 32a, and the resin sheet 23 can be suctioned through the vacuum suction hole to be shaped into a shape that conforms to the inner surface of the cavity portion 32a of the mold 32. The vacuum suction hole is a very small hole, one end of which passes through the interior of the mold 32 and communicates with the inner surface of the cavity portion 32a, and the other end of which is connected to a pressure reducing device.

[0018] The outer frame 33 includes a frame portion 33t, a frame portion 33b, a frame portion 33r, and a frame portion 33l. Groove-shaped vacuum suction holes 33s are provided in the outer frame 33. The vacuum suction holes 33s are connected to a vacuum device and are configured to allow the resin sheet 23 to be adsorbed to the outer frame 33 by vacuum suction.

[0019] Frame portion 33t, frame portion 33b, frame portion 33r, and frame portion 33l are respectively arranged on the upper side, lower side, right side, and left side of mold 32 and are configured to be independently movable. That is, frame portion 33t, frame portion 33b, frame portion 33r, and frame portion 33l are respectively arranged along top surface 32st, bottom surface 32sb, side surface 32sr, and side surface 32sl of mold 32 and are configured to be movable parallel to each surface. Frame portion 33r and frame portion 33l are arranged so as to be sandwiched between frame portion 33t and frame portion 33b.

[0020] The right-side mold 32 shown in FIG. 1 is the mold in which the core material 3 is pressed against the resin sheet 23 formed in this mold 32. The right-side mold 32 is provided with a protruding member 32B. The protruding member 32B is configured to be able to move forward and backward (protrude and retract). Specifically, as shown in FIGS. 2B and 2C, the protruding member 32B is configured to be able to protrude from the mold 32 side (the mold 32 side on which the protruding member 32B is provided) to the resin sheet 23 side (see FIG. 5B). By protruding, the protruding member 32B engages with the core material 3, and has the function of preventing the core material 3 welded to the resin sheet 23 from shifting position. In other words, by protruding and engaging with the core material 3, the core material 3 is temporarily held to the resin sheet 23.

[0021] As shown in Figures 2B and 2C, the protruding member 32B has a piercing portion 32B1 and a base portion 32B2. The piercing portion 32B1 is a portion that protrudes from the space within the mold 32 through the hole 32A of the mold 32 into the cavity portion 32a of the mold 32. The piercing portion 32B1 is connected to the base portion 32B2. The base portion 32B2 is provided within the mold 32. By coming into contact with the mold 32, the base portion 32B2 has the function of determining the most protruding position and the most retracted position of the protruding member 32B.

[0022] Note that protruding member 32B may be configured to be driven by air pressure or hydraulic pressure, for example, and the mechanism for driving protruding member 32B is not particularly limited. Also, hole 32A from which protruding member 32B protrudes is preferably subjected to suction. This makes it easier for piercing portion 32B1 to pierce resin sheet 23 or core material 3. Also, in the first embodiment, holes are formed in structure 100 by protruding member 32B, but these holes may be left open or may be filled after molding of structure 100 is completed.

[0023] In the first embodiment, the protruding member 32B is movably engaged (one example of joining) with the mold 32. Specifically, the protruding member 32B is held in the mold 32 by engaging with the inner surface Sf of the accommodation space Sp shown in FIG. 2C. That is, the base 32B2 is engaged with the inner surface Sf, thereby holding the protruding member 32B in the mold 32. The accommodation space Sp is a space within the mold 32, and accommodates the base 32B2. The inner surface Sf is a surface that defines the accommodation space Sp and faces the accommodation space Sp.

[0024] As shown in FIGS. 4 and 6C, the overall thickness of the core material 3 (the width of the core material 3 in a direction parallel to the opening and closing direction of the mold 32) is w1, and the width (depth) of the protruding member 32B penetrating the core material 3 is w2. In this case, the ratio w2 / w1 is, for example, 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, or 0.90. The ratio w2 / w1 can also be defined within a range between any two of the values ​​exemplified here. For example, if the penetration width (depth) is too short, temporary retention may be insufficient, while if the penetration width (depth) is too long, the strength of the structure 100 may be reduced accordingly. So, for example, the ratio w2 / w1 can be 0.20, 0.25, 0.30, 0.35, 0.40, or 0.45.

[0025] In Fig. 7, when the core material 3 is viewed from above, a line that bisects the core material 3 horizontally is designated as L1, and an imaginary line that bisects the core material 3 vertically is designated as L2. As a result, the surface of the core material 3 that faces the mold 32 is divided into four regions Rg1 to Rg4 as shown in Fig. 7. Also in Fig. 7, temporary holding positions p1 to p4 correspond to positions where the protruding members 32B are inserted. In the first embodiment, temporary holding positions p1 to p4 are located in each of the four regions Rg1 to Rg4, and the core material 3 is temporarily held evenly by the protruding members 32B.

[0026] In FIG. 7, the total height of the core material 3 is H. Furthermore, the distance from the upper end (top) of the core material 3 to the uppermost temporary holding positions (temporary holding positions p1 and p2 in the example of FIG. 7) is w3. In this case, the ratio w3 / H is 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, or 0.45. The ratio w3 / H can also be defined within a range between any two of the numerical values ​​exemplified here.

[0027] 7, the distance from the bottom end (bottom) of the core material 3 to the lowest one of the temporary holding positions (temporary holding positions p3 and p4 in the example of FIG. 7) is defined as w4. In this case, the ratio w4 / H is 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, or 0.45. The ratio w4 / H can also be defined within a range between any two of the numerical values ​​exemplified here. Note that if the upper portion of the core material 3 is not temporarily held properly, the core material 3 may fall off. Therefore, for example, it is preferable that the ratio w4 / H be greater than the value of the ratio w3 / H.

[0028] In FIG. 7, the width of the core material 3 (the width in the direction perpendicular to the thickness and height directions) is Wt. The distance from the right end of the core material 3 to the rightmost temporary holding position (temporary holding positions p2 and p4 in the example of FIG. 7) is w5. In this case, the ratio w5 / H is 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, or 0.50. The ratio w5 / H can also be defined within a range between any two of the values ​​shown here. A ratio w5 / H of 0.50 indicates that the temporary holding position is located on line L1. Although a detailed explanation will be omitted, the relationship between Wt and the distance from the left end of the core material 3 to the leftmost temporary holding position (in the example of Figure 7, temporary holding positions p1 and p3) can also be defined in the same way as the ratio w5 / H.

[0029] The arrangement of the temporary holding positions is not limited to the configuration shown in Fig. 7. From the viewpoint of preventing the core material 3 from falling off, for example, the temporary holding positions may be provided only above the line L2. 7, the temporary holding positions are evenly distributed in regions Rg1 to Rg4, but this is not limiting and they may be biased toward one of the regions. For example, the number of temporary holding positions in region Rg1 may be greater than the number of temporary holding positions in region Rg3, and the number of temporary holding positions in region Rg2 may be greater than the number of temporary holding positions in region Rg4.

[0030] <Insertion Device 19> The insertion device 19 is configured to be movable by a drive mechanism (not shown) and includes a suction pad (not shown) configured to be able to hold the core material 3 by suction.

[0031] 1-2. Manufacturing method of structure 100 Next, a description will be given of a method for manufacturing the structure 100. The method of this embodiment includes a hanging step, an adsorption step, a shaping step, a core material placement step, and a mold clamping step.

[0032] 1-2-1. Drooping process In the hanging step, as shown in FIG. 1, the resin sheet 23 extruded from the T-die 18 is hung down on the front side (front surface 32f side) of the mold 32.

[0033] 1-2-2. Adsorption process In the suction step, as shown in FIG. 3A, the outer frame 33 (frame portions 33t, 33b, 33r, and 33l) is advanced to suction the resin sheet 23 to the outer frame 33. Then, as shown in FIG. 3B, the outer frame 33 is moved so that the resin sheet 23 approaches the mold 32. Specifically, with the outer frame 33 in contact with the resin sheet 23, a decompression device connected to the decompression suction holes 33s of the outer frame 33 is activated to suction the resin sheet 23 to the outer frame 33. In this state, by retracting the outer frame 33, the resin sheet 23 moves together with the outer frame 33 toward the mold 32, and the resin sheet 23 comes into contact with the pinch-off portion 32b. As a result, the cavity portion 32a of the mold 32 is blocked by the resin sheet 23, and the cavity portion 32a becomes an airtight space.

[0034] 1-2-3. Shaping process 4A, in the shaping step, the resin sheet 23 is suctioned under reduced pressure through the vacuum suction holes in the cavity portion 32a of the mold 32, and the resin sheet 23 is shaped into a shape that conforms to the inner surface of the cavity portion 32a. In the first embodiment, the protruding members 32B are retracted (pulled back) during the shaping step.

[0035] 1-2-4. Core material placement process In the core material placement process, the core material 3 is welded to the resin sheet 23. Specifically, as shown in FIG. 4B, the insertion device 19 holding the core material 3 is placed between a pair of molds 32. The core material is then placed in front of the resin sheet 23 that has been shaped into the cavity portion 32a. Next, as shown in FIG. 5A, the insertion device 19 is moved toward the resin sheet 23, thereby attaching the core material 3 to the cavity portion 32a of the resin sheet 23.

[0036] In the first embodiment, the core material 3 is made of resin, and the resin sheet 23 is melted. Therefore, the core material 3 and the resin sheet 23 are thermally welded to a certain extent, and the core material 3 is held in a predetermined position. However, inexpensive polystyrene has poor thermal weldability compared to resins made of polyethylene or containing polyethylene, so the core material 3 may become misaligned. Therefore, in the first embodiment, as shown in FIG. 5B , after the core material 3 is attached to the cavity portion 32a of the resin sheet 23, the protruding member 32B is advanced to pierce the resin sheet 23 and the core material 3 with the protruding member 32B. In this way, the core material 3 is temporarily held on the surface of the resin sheet 23 by being pierced and engaging with the protruding member 32B. At this time, the core material 3 is also thermally welded to the resin sheet 23, so that the core material 3 is more securely held on the resin sheet 23.

[0037] The timing at which the protruding member 32B advances will be described. For example, the core member 3 can be attached to the resin sheet 23 and brought into contact with the resin sheet 23 while the protruding member 32B is advanced. Alternatively, the protruding member 32B may be advanced before a predetermined time has elapsed from the time when the core material 3 contacts the resin sheet 23. The predetermined time (seconds) may be, for example, 0.1, 0.3, 0.5, 0.7, 0.9, 1.1, 1.3, 1.5, 1.7, 1.9, 2.1, 2.3, 2.5, 2.7, 2.9, 3.1, 3.3, 3.5, 3.7, 3.9, 4.1, 4.3, 4.5, 4.7, 4.9, or 5.0, and may be defined within a range between any two of the numerical values ​​exemplified here.

[0038] As shown in Figure 6A, after the protruding member 32B pierces the core material 3, the insertion device 19 releases the operation of holding the core material 3 (in the first embodiment, suction by the suction pad of the insertion device 19), and further, the insertion device 19 retreats to a position outside the movement trajectory of the mold 32.

[0039] 1-2-5. Mold clamping process In the mold clamping process, as shown in FIG. 6B, the pair of molds 32 are clamped together. This results in a structure 100 shaped to fit the inner surface of the cavity formed by the pair of molds 32. The outside of the pinch-off portion 32b becomes a flash 23b. Once the pair of molds 32 are clamped together, temporary holding of the core material 3 is no longer necessary, so the protruding member 32B may be retracted. Note that, in the mold clamping process, the protruding member 32B may be retracted when the mold 32 starts to move, or while the mold 32 is moving. Note that, if the resin sheet 23 of the left mold 32 shown in FIG. 6A comes into contact with the core material 3, a certain amount of pressure may be applied to the core material 3, which may cause problems such as damage to the protruding member 32B. Therefore, the protruding member 32B may be retracted before the pair of molds 32 are clamped together.

[0040] Thereafter, the mold 32 is opened to take out the structure 100, and the burrs 23b are removed, thereby obtaining the desired structure 100.

[0041] 1-3. Functions and Effects of the First Embodiment In the manufacturing method of the structure 100 according to the first embodiment, in the core material placement process, the core material 3 is temporarily held to the resin sheet 23 by the protruding member 32B provided on the mold 32, so that misalignment of the core material 3 can be suppressed, and any hindrance to the smooth manufacturing of the structure 100 can be avoided.

[0042] Because the core material 3 is temporarily held to the resin sheet 23 by the protruding members 32B, it is possible to suppress the occurrence of constraints on manufacturing conditions. For example, if the resin sheet 23 is made of polypropylene, it is preferable that the resin used for the core material 3 be a polyethylene resin or a resin containing polyethylene, from the viewpoint of thermal welding properties. However, polyethylene is more expensive than polystyrene, and therefore has the disadvantage of increasing manufacturing costs. In the first embodiment, because the core material 3 is temporarily held to the resin sheet 23 by the protruding members 32B, it is possible to prevent the core material 3 from shifting position or falling off the resin sheet 23, even if the resin sheet 23 is made of polypropylene and the resin used for the core material 3 is polystyrene.

[0043] 1-4. Variations 1-4-1. Variation 1: Sharing with degassing needle As shown in FIG. 8, the method for manufacturing the structure 100 according to the embodiment may further include a degassing step. The degassing step is a step of discharging air from the closed space of the cavity portion 32a after the mold closing step is completed. In a modified example, the protruding member 32B is configured as a hollow needle-like member to enable degassing. That is, the protruding member 32B is formed with an air intake port 32B3 for discharging air from the cavity portion 32a. Furthermore, the core material 3 is formed with a space 3a to ensure degassing. In a modified example, the space 3a is a recess.

[0044] In the core material placement process, when the core material 3 is inserted into and temporarily held by the protruding member 32B, the air intake port 32B3 of the protruding member 32B is exposed from the core material 3. In the mold closing process, the mold 32 is closed to make the cavity portion 32a a closed space. Then, in the deaeration process, air inside the cavity portion 32a is sucked in through the air intake port 32B3 of the protruding member 32B and exhausted from the cavity portion 32a.

[0045] 1-4-2. Modification 2: Timing of advancement of protruding member 32B In the first embodiment, in the core material placement step, the protruding member 32B is advanced after the core material 3 is attached to the cavity portion 32a of the resin sheet 23, but the timing of the advancement is not limited to this. For example, the protruding member 32B may be advanced and pierced into the resin sheet 23 so as to penetrate the resin sheet 23 immediately after the shaping step is completed. Then, in the core material placement step, the insertion device 19 can place the core material 3 in the resin sheet 23 while piercing the core material 3 into the protruding member 32B exposed from the resin sheet 23.

[0046] 1-4-3. Modification 3: Core material 3 is covered with skin material One of the two surfaces of the core material 3 facing the mold 32 may be covered with a skin material (for example, a fibrous material such as a nonwoven fabric). In this case, the surface covered with the skin material faces the mold 32 on the left side shown in Fig. 1, and the surface not covered with the skin material faces the mold 32 on the right side (the mold 32 that is attached in the core material placement step). This allows the surface of the core material 3 where the resin is exposed to come into contact with the heated resin sheet 23 quickly, improving the thermal welding effect. If the surface not covered by the skin material were to face the left mold 32, the surface not covered by the skin material would come into contact with the resin sheet 23 of the left mold 32 after the surface covered by the skin material is placed in the right mold, increasing the time it takes for the exposed resin portion of the core material 3 to come into contact with the resin sheet 23. If this time increases, the resin sheet 23 cools, deteriorating the weldability and, as a result, the molded body (structure) becomes weak against bending loads. To avoid this, in Modification 3, the surface not covered by the skin material is placed facing the right mold 32 (the mold 32 that is attached in the core material placement process).

[0047] 1-4-4. Modification 4: Shape of core material 3 In the first embodiment, the core material 3 is described as being a flat plate-like member, but is not limited to this. The core material 3 may be configured with a structure having multiple hollow portions extending in the thickness direction of the core material 3. Specifically, the core material 3 may be configured with a honeycomb structure. The protruding members 32B may temporarily hold the core material 3 by piercing the core material 3 itself, or may temporarily hold the core material 3 by protruding into the hollow portion of the core material 3 so that the core material 3 is caught by the protruding members 32B. This makes it possible to prevent holes from being formed in the core material 3.

[0048] 2. Second embodiment In the second embodiment, only the differences from the first embodiment will be described, and the description of the other same configurations will be omitted. In the second embodiment, a member 3b (an example of a separate member) independent from the core material 3 is used instead of the protruding member 32B. In other words, the mold device 31 does not include the protruding member 32B.

[0049] 9A and 9B is a skin material, specifically made of a fibrous material (nonwoven fabric in the second embodiment) that covers a portion of the surface of the core material 3. One surface of the member 3b is bonded to the resin of the core material 3 by being previously welded thereto. In the core material placement step, the other surface of the member 3b comes into contact with the resin sheet 23 together with the core material 3. At this time, the member 3b is effectively bonded to the resin sheet 23 by an anchor effect. That is, in the second embodiment, the member 3b is bonded (an example of bonding) to the core material 3 so as to create an anchor effect, and is also bonded to the resin sheet 23 so as to create an anchor effect. As a result, the core material 3 is temporarily held to the resin sheet 23 via the member 3b.

[0050] Furthermore, the member 3b, which is independent from the core material 3, may be made of a welding member instead of a skin material. The material of the welding member of the member 3b may be, for example, polyethylene resin or a hot melt adhesive. The welding member is attached to a portion of the surface of the core material 3 (an example of bonding), and is made of a resin that is more easily welded to the resin sheet 23 than the resin that constitutes the core material 3. The welding member, member 3b, is effectively welded to the resin sheet 23, and the core material 3 is temporarily held to the resin sheet 23.

[0051] The position of the member 3b in the second embodiment can be defined in the same way as the temporary holding position explained with reference to FIG. 7 in the first embodiment.

[0052] In the second embodiment, the area of ​​the member 3b (skin material or welding member) when viewed in a plane is defined as A1, and the area of ​​the core material 3 when viewed in a plane as shown in FIG. 7 is defined as A2 (H×Wt in FIG. 7). Note that if a plurality of members 3b are provided on the core material 3, A1 is defined as the total area. In this case, the ratio A1 / A2 is, for example, 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, or 0.90, and can also be defined within a range between any two of the numerical values ​​exemplified here.

[0053] The second embodiment also has the same effects as the first embodiment.

[0054] Moreover, the first embodiment may be combined with the second embodiment. That is, the mold device 31 may be provided with the protruding member 32B, and the core material 3 may be provided with the member 3b. [Explanation of symbols]

[0055] 1: Molding machine 2: Resin sheet forming device 3: Core material 3a: Space part 3b: Component 11: Raw resin 12: Hopper 13: Extruder 13a: Cylinder 17: Accumulator 17a: Cylinder 17b: Piston 18: T-die 19: Insertion device 23: Resin sheet 23b: Bali 25: Connecting pipe 27: Connecting pipe 31: Mold equipment 32: Mold 32A: Hole 32B: Protruding member 32B1: Pierce part 32B2: Base 32B3: Air intake 32a: Cavity part 32b: Pinch-off section 32f:Front 32r: Rear 32s: Peripheral surface 32sb: bottom 32sl: Side 32sr: side 32st:Top surface 33: Outer frame 33b: Frame 33l: Frame 33r: Frame 33s: Decompression suction hole 33t: Frame 100 :Structure Sf:Interior Sp: Containment space

Claims

1. A method for manufacturing a structure, comprising: The method includes a hanging process, a shaping process, and a core material placement process. In the hanging step, a molten resin sheet is hung down on the front side of a mold, In the shaping step, the hanging resin sheet is shaped in a cavity portion of the mold, In the core material placement step, a core material is placed in the resin sheet formed in the cavity portion, the core material is temporarily held on the resin sheet by a separate member independent of the core material, the separate member is a protruding member, the protruding member is provided in the mold and configured to be able to protrude from the mold side toward the resin sheet side, In the core material positioning step, the core material is temporarily held in the resin sheet by engaging with the protruding member.

2. 10. The method of claim 1, Further comprising a mold closing step and a degassing step, The protruding member is formed with an air intake port for discharging air from within the cavity portion, In the core material positioning step, when the core material is engaged with the protruding member, the air intake port of the protruding member is exposed from the core material, In the mold closing step, the mold is closed to form the cavity portion into a closed space, In the degassing step, air in the cavity is sucked through the air inlet of the protruding member and exhausted from the cavity.

3. 3. The method of claim 1 or claim 2, The resin sheet is made of polypropylene, The method wherein the core material is comprised of polystyrene.

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