JP6923797B2 - Structure and its manufacturing method - Google Patents

Description

The present invention relates to a board-like structure such as a deck board and a method for manufacturing the same.

Patent Document 1 discloses a method of manufacturing a resin panel having high rigidity by insert molding a reinforcing member between two molten resin sheets.

Japanese Unexamined Patent Publication No. 2013-176905

However, when the reinforcing member is inserted at the time of molding the resin sheet, if the insert accuracy is poor, the reinforcing member may be sandwiched by the mold at the time of mold clamping. Therefore, in consideration of variation, a reinforcing member slightly shorter than the product size is used, but in order to improve the rigidity, it is ideal that the reinforcing member is inserted to a position close to the product terminal.

The present invention has been made in view of such circumstances, and provides a structure in which a reinforcing member can be easily inserted.

According to the present invention, it is a structure having a foam molded body having a panel portion, and the panel portion has a back surface and a front surface facing each other, a recess is provided on the back surface, and the recess is reinforced. A structure is provided in which the members are press-fitted.

In the present invention, a foam molded body having a recess is formed in advance in the panel portion, and the reinforcing member is press-fitted into the recess to arrange the reinforcing member in the panel portion. According to such a configuration, since it is not necessary to insert the reinforcing member at the time of molding, problems caused by insert molding can be avoided. Further, since it is not necessary to consider the insert accuracy, it is easy to provide the reinforcing member to a position close to the end of the foam molded product.

Hereinafter, various embodiments of the present invention will be illustrated. The embodiments shown below can be combined with each other.
Preferably, the reinforcing member has an elongated shape and is press-fitted into the recess from the out-of-plane direction of the back surface.
Preferably, the panel portion includes a left panel portion and a right panel portion, and the left panel portion and the right panel portion are rotatably connected to each other by a hinge portion.
Preferably, the left panel portion and the right panel portion are provided with a back surface and a front surface facing each other, respectively, a left recess is provided on the back surface of the left panel portion, and the back surface of the right panel portion is provided with a left recess. , A right recess is provided, a part of the reinforcing member is press-fitted into the left recess in a state where the left panel portion and the right panel portion are folded by the hinge portion, and the other part of the reinforcing member is the right. It is press-fitted into the recess.
Preferably, the skin material straddling the left panel portion, the hinge portion, and the right panel portion is provided on the front surface side.
Preferably, the panel portion includes a central layer and surface layers provided on both sides thereof, and the surface layer is a layer having a thickness of up to 10% from the surface of the panel portion with respect to the wall thickness of the panel portion. The central layer is a layer having a thickness of 25 to 50% from the surface of the panel portion with respect to the wall thickness of the panel portion, and the average cell diameter of the central layer is the average cell diameter of the surface layer. Greater than.
Preferably, the ratio of (average cell diameter of the central layer) / (average cell diameter of the surface layer) is 1.2 to 10.

According to another aspect of the present invention, it is a method for manufacturing a structure including a molding step and a press-fitting step. In the molding step, a foamed resin parison is molded to form a foamed molded product having a panel portion. A method for manufacturing a structure is provided, wherein the panel portion is provided with a back surface and a front surface facing each other, and the back surface is provided with a recess, and in the press-fitting step, a reinforcing member is press-fitted into the recess. NS.

Preferably, the molding step includes an arranging step and an expansion step, the foamed resin parison is one foamed resin sheet, and in the arranging step, the foamed resin sheet is placed between the first and second molds. In the expansion step, the first and second molds are brought close to each other so that a gap larger than the thickness of the foamed resin sheet is provided between the first and second molds. 2 A method for manufacturing a structure, in which the foamed resin sheet is expanded to the thickness of the gap by sucking the foamed resin sheet under reduced pressure with both molds.
Preferably, the reinforcing member has an elongated shape and is press-fitted into the recess from the out-of-plane direction of the back surface.
Preferably, the panel portion includes a left panel portion and a right panel portion, the left panel portion and the right panel portion are rotatably connected to each other by a hinge portion, and the hinge portion connects the foamed resin parison to the foam resin parison. It is formed by compressing with a mold.
Preferably, in the molding step, the skin material straddling the left panel portion, the hinge portion, and the right panel portion is integrally molded with the foam molded body on the front surface side.

It is a perspective view which shows the foam molded body 24, the skin material 3 and the reinforcing member 4 which make up the structure 10 of one Embodiment of this invention, and shows the state which the reinforcing member 4 is not inserted into the foam molded body 24. It is sectional drawing of the surface of the foam molded body 24 and the skin material 3 in FIG. 1 passing through points AAA. It is a perspective view which shows the structure 10 of one Embodiment of this invention, and shows the state which the reinforcing member 4 was press-fitted into the foam molded body 24. It is a perspective view which shows the structure 10 of one Embodiment of this invention, and shows the state which the foam molded body 24 and the skin material 3 are folded by the hinge part 5. An example of a foam molding machine 1 that can be used in the method for manufacturing a structure according to an embodiment of the present invention is shown. FIG. 5 is an enlarged cross-sectional view of the vicinity of the first and second molds 21 and 22 and the foamed resin sheet 23 of FIG. FIG. 6 shows a state in which the foamed resin sheet 23 is sucked under reduced pressure by the first mold 21 from the state of FIG. 6 to shape the foamed resin sheet 23 into a shape along the cavity 21b of the first mold 21. It is a corresponding cross-sectional view. FIG. 6 is a cross-sectional view corresponding to FIG. 6, showing a state in which the molds 21 and 22 are brought close to each other from the state of FIG. 7. FIG. 6 shows a state in which the foamed resin sheet 23 is sucked under reduced pressure by the second mold 22 from the state of FIG. 8 to expand the foamed resin sheet 23 to the thickness of the gap G between the molds 21 and 22. It is a cross-sectional view corresponding to. It is sectional drawing corresponding to FIG. 6 which shows the state which took out the foam molded body 24 which attached the burr 23b from the mold 21 and 22. A cross-sectional photograph of the foam molded product 24 obtained in the reference example of the present invention is shown. An example of the form of bubbles for explaining the calculation method of the tentative average bubble diameter is shown. It is a perspective view which shows the structure 10 of the modification of this invention, and shows the state which the reinforcing member 4 was press-fitted into the foam molded body 24.

Hereinafter, embodiments of the present invention will be described. The various features shown in the embodiments shown below can be combined with each other. In addition, the invention is independently established for each feature.

1. 1. Structure With reference to FIGS. 1 to 4, the structure 10 according to the embodiment of the present invention will be described. The structure 10 includes a foam molded body 24 and a reinforcing member 4. The foam molded body 24 includes a board-shaped left panel portion 6 and a right panel portion 7 (“panel portion” within the scope of claims). The left panel portion 6 and the right panel portion 7 are rotatably connected to each other by a hinge portion 5.

The foam molded product 24 is a molded product made of a foamed resin. The foaming ratio of the foam molded product 24 is not particularly limited, but is, for example, 1.5 to 6 times, and specifically, for example, 1.5, 2, 2.5, 3, 3.5, 4, 4. It is 5, 5, 5.5, and 6 times, and may be within the range between any two of the numerical values exemplified here.

The left panel portion 6 includes a back surface 6r and a front surface 6f facing each other. The right panel portion 7 includes a back surface 7r and a front surface 7f facing each other. The back surfaces 6r and 7r are provided with a left recess 6a and a right recess 7a, respectively. As shown in FIGS. 3 to 4, the reinforcing member 4 is foamed by press-fitting the reinforcing member 4 into the recesses 6a and 7a in a state where the left panel portion 6 and the right panel portion 7 are folded by the hinge portion 5. It is fixed to the molded body 24.

The reinforcing member 4 is a member having higher rigidity than the foam molded body 24, and is made of, for example, a metal (aluminum or the like) or a hard plastic. The reinforcing member 4 can be press-fitted from the back surface 6r and 7r from the out-of-plane direction. Since the reinforcing member 4 is press-fitted from such a direction, the reinforcing member 4 does not have to be linear, and can have an arbitrary shape such as a curved shape, a branched shape, and a plate shape. In this case, the recesses 6a and 7a have a shape that allows the reinforcing member 4 to be press-fitted. Therefore, the reinforcing member 4 can be shaped, for example, along the curved side surface 24a. The reinforcing member 4 preferably has an elongated shape, has a constant cross-sectional shape along the longitudinal direction thereof, and has a length ratio to a width of 10 or more. The reinforcing member 4 is exposed on the back surface side.

The reinforcing member 4 is press-fitted into the recesses 6a and 7a while deforming the foam molded body 24. Since the foam molded body 24 is more easily deformed than the non-foamed molded body, the reinforcing member 4 can be easily press-fitted. Further, since the foam molded body 24 has higher flexibility than the non-foamed molded body, the reinforcing member 4 is held in the recesses 6a and 7a without rattling.

If the left panel portion 6 and the right panel portion 7 are simply folded by the hinge portion 5, the left panel portion 6 and the right panel portion 7 will be in an open state due to the restoring force of the hinge portion 5. However, in the present embodiment, since a part of the reinforcing member 4 is press-fitted into the left recess 6a and another part of the reinforcing member 4 is press-fitted into the right recess 7a, the left panel portion 6 and the right panel portion 7 are press-fitted. The folded state is maintained by the reinforcing member 4. Further, by fitting the convex portion 24c provided on the left panel portion 6 and the concave portion 24d provided on the right panel portion 7, the opening of the left panel portion 6 and the right panel portion 7 is suppressed. In the present embodiment, the convex portion 24c and the concave portion 24d have substantially the same width, but the width of the convex portion 24c may be larger than the width of the concave portion 24d as in the modified example shown in FIG. In this case, the convex portion 24c can be strongly fitted to the concave portion 24d by press-fitting the convex portion 24c into the concave portion 24d.

Since the recesses 6a and 7a extend to a position close to the terminal 24b of the foam molded body 24, the reinforcing member 4 is provided to a position close to the terminal 24b of the foam molded body 24. In other words, the recesses 6a and 7a are provided over the substantially overall length of the foam molded body 24, and the reinforcing member 4 is provided over the substantially overall length of the recesses 6a and 7a. When the reinforcing member 4 is inserted at the time of molding the foam molded body 24, it is difficult to arrange the reinforcing member 4 in this way, but in the present embodiment, the reinforcing member 4 is press-fitted after molding the foam molded body 24. Therefore, it is possible to arrange in this way, and the strength of the foam molded body 24 is enhanced. Further, since the reinforcing member 4 is not exposed from the terminal 24b, the design is excellent. The distance between the terminal 24b of the foam molded product and the end face of the reinforcing member 4 is preferably 0.2 to 2 mm, more preferably 0.5 to 1.5 mm.

On the front surface side of the foam molded body 24, a skin material 3 straddling the left panel portion 6, the hinge portion 5, and the right panel portion 7 is provided. As shown in FIGS. 3 to 4, when the left panel portion 6 and the right panel portion 7 are folded by the hinge portion 5, the back surfaces 6r and 7r come into contact with each other and cannot be seen from the outside, and both the upper surface and the lower surface of the structure 10 are invisible. Is covered with the skin material 3. As described above, according to the present embodiment, although the skin material 3 is provided only on one side of the foam molded body 24, both sides are formed by folding the left panel portion 6 and the right panel portion 7 at the hinge portion 5. A structure 10 provided with the skin material 3 can be obtained. The skin material 3 is preferably made of a breathable member such as a non-woven fabric, and is preferably integrally molded with the foam molded body 24 at the time of molding the foam molded body 24.

2. Configuration of Foam Molding Machine 1 With reference to FIGS. 5 to 6, the foam molding machine 1 that can be used to carry out the method for manufacturing a structure according to an embodiment of the present invention will be described. The foam molding machine 1 includes a resin supply device 2, a T-die 18, and dies 21 and 22. The resin supply device 2 includes a hopper 12, an extruder 13, an injector 16, and an accumulator 17. 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.
Hereinafter, each configuration will be described in detail.

<Hopper 12, extruder 13>
The hopper 12 is used to put the raw material resin 11 into the cylinder 13a of the extruder 13. The form of the raw material resin 11 is not particularly limited, but is usually in the form of pellets. The raw material resin is, for example, a thermoplastic resin such as polyolefin, and examples of the polyolefin include low-density polyethylene, linear low-density polyethylene, high-density polyethylene, polypropylene, ethylene-propylene copolymer and a mixture thereof. The raw material resin 11 is charged into the cylinder 13a from the hopper 12 and then melted by being heated in the cylinder 13a to become a molten resin. Further, it is conveyed toward the tip of the cylinder 13a by the rotation of the screw arranged in the cylinder 13a. The screw is arranged in the cylinder 13a, and the molten resin is kneaded and conveyed by its rotation. A gear device is provided at the base end of the screw, and the screw is rotationally driven by the gear device. The number of screws arranged in the cylinder 13a may be one or two or more.

<Injector 16>
The cylinder 13a is provided with an injector 16 for injecting a foaming agent into the cylinder 13a. Examples of the foaming agent injected from the injector 16 include a physical foaming agent, a chemical foaming agent, and a mixture thereof, and a physical foaming agent is preferable. As the physical foaming agent, inorganic physical foaming agents such as air, carbon dioxide, nitrogen gas, and water, organic physical foaming agents such as butane, pentane, hexane, dichloromethane, and dichloroethane, and their supercritical fluids are used. be able to. As the supercritical fluid, it is preferable to use carbon dioxide, nitrogen, etc., for nitrogen, the critical temperature is -149.1 ° C, the critical pressure is 3.4 MPa or more, and for carbon dioxide, the critical temperature is 31 ° C, the critical pressure. It is obtained by setting the pressure to 7.4 MPa or more. Examples of the chemical foaming agent include those that generate carbon dioxide gas by a chemical reaction between an acid (eg, citric acid or a salt thereof) and a base (eg, baking soda). The chemical foaming agent may be injected from the hopper 12 instead of being injected from the injector 16.

<Accumulator 17, T-die 18>
The foamed resin obtained by melt-kneading the raw material resin and the foaming agent 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 slidable inside the cylinder 17a, so that foamed resin can be stored in the cylinder 17a. Then, by moving the piston 17b after a predetermined amount of the foamed resin is stored in the cylinder 17a, the foamed resin is pushed out from the slit provided in the T die 18 through the connecting pipe 27 and hung down to form the foamed resin sheet 23. Form.

<1st and 2nd molds 21 and 22>
The foamed resin sheet 23 is guided between the first and second molds 21 and 22. The first mold 21 is provided with a large number of vacuum suction holes, and the foamed resin sheet 23 can be suctioned under reduced pressure to form a shape along the inner surface 21a of the first mold 21. There is. A pinch-off portion 21d is provided so as to surround the cavity 21b of the first mold 21. The second mold 22 is provided with a large number of decompression suction holes, and the foamed resin sheet 23 can be suctioned under reduced pressure to form a shape along the inner surface 22a of the second mold 22. There is. The inner surface 22a is provided with convex portions 22b, 22c, 22e and concave portions 22d.

3. 3. Method for Manufacturing a Structure Here, a method for manufacturing a structure according to an embodiment of the present invention will be described with reference to FIGS. 5 to 10. The method of this embodiment includes a molding step and a press-fitting step. The molding step may include a placement step, an expansion step, and a finishing step. Hereinafter, a detailed description will be given.

3.1 Molding step (1) Arrangement step In this step, as shown in FIGS. 5 and 6, one foamed resin sheet 23 formed by extruding the molten foam resin from the slit of the T die 18 and hanging it down. Is placed between the molds 21 and 22. Further, the mold 21 is fitted with a skin material sheet 28 made of a breathable member such as a non-woven fabric.

In the present embodiment, since the direct vacuum molding using the foamed resin sheet 23 extruded from the T die 18 as it is is performed, the foamed resin sheet 23 is not cooled to room temperature and solidified before molding. The solidified foamed resin sheet 23 is not heated before molding. Further, the foamed resin sheet 23 of the present embodiment has a substantially uniform temperature as a whole immediately after being extruded from the slit, and is gradually cooled from the surface by the atmosphere while being hung down. The foamed resin sheet 23 of the present embodiment is less affected by cooling by the atmosphere toward the center in the thickness direction of the foamed resin sheet 23. Therefore, the temperature of the foamed resin sheet 23 of the present embodiment rises toward the center in the thickness direction to increase the viscosity. Has the property of becoming low. The wall thickness of the foamed resin sheet 23 is not particularly limited, but is, for example, 0.5 to 5 mm, preferably 1 to 3 mm. Specifically, the wall thickness is, for example, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5 mm, and any of the numerical values exemplified here. It may be within the range between the two.

(2) Expansion Step In this step, as shown in FIGS. 7 to 9, the molds 21 and 22 are brought close to each other so that a gap G larger than the thickness of the foamed resin sheet 23 is provided between the molds 21 and 22. By sucking the foamed resin sheet 23 under reduced pressure with both the molds 21 and 22 in this state, the foamed resin sheet 23 is expanded to the thickness of the gap G.

In the present embodiment, the mold 21 is provided with the pinch-off portion 21d, and when the molds 21 and 22 are brought close to each other until the pinch-off portion 21d comes into contact with the mold 22, they are surrounded by the molds 21 and 22 and the pinch-off portion 21d. The space to be closed becomes the closed space S. The portion 23a of the foamed resin sheet 23 in the closed space S becomes the foamed molded product 24. The portion 28a of the skin material sheet 28 in the closed space S becomes the skin material 3. On the other hand, the portions of the foamed resin sheet 23 and the skin material sheet 28 outside the closed space S are burrs 23b and 28b. At this time, the convex portion 22c of the mold 22 is pressed against the foamed resin sheet 23, so that the foamed resin sheet 23 is compressed and the hinge portion 5 is formed.

The thickness of the gap G is not particularly limited, but is preferably 1.1 to 3.0 times the thickness of the foamed resin sheet 23. Specifically, (thickness of gap G) / (thickness of foamed resin sheet 23) is, for example, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1 .7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9 , 3.0, and may be within the range between any two of the numerical values exemplified here.

In the decompression suction by the molds 21 and 22, the decompression suction by the first mold 21 may be started first, the decompression suction by the second mold 22 may be started first, and the decompression suction by the molds 21 and 22 may be started first. Decompression suction may be started at the same time. Further, the decompression suction by the first mold 21 may be stopped first, the decompression suction by the second mold 22 may be stopped first, or the decompression suction by the molds 21 and 22 may be stopped at the same time. good. The decompression suction by the molds 21 and 22 may be started before the molds 21 and 22 are brought close to each other, or may be started after the molds 21 and 22 are brought close to each other.

When the foamed resin sheet 23 is sucked under reduced pressure by both the molds 21 and 22, the foaming of the foamed resin sheet 23 is promoted and the foamed resin sheet 23 expands. Since the foamed resin sheet 23 has the lowest viscosity (highest fluidity) near the center in the thickness direction, foaming near the center in the thickness direction is particularly promoted and the foamed resin sheet 23 expands. As a result, a foam molded body 24 having panel portions 6 and 7 having a structure in which the average cell diameter in the layer near the center (central layer) in the thickness direction is large and the average cell diameter in the surface layer near the surface is small is obtained. Be done. Such panel portions 6 and 7 are lightweight and highly rigid because the central layer having a large average cell diameter has a sandwich structure sandwiched between surface layers having a small average cell diameter.

As shown in the cross-sectional photograph of FIG. 11, the panel portions 6 and 7 obtained by the method of the present embodiment have a thickness of up to 10% from the surface of the panel portions 6 and 7 with respect to the wall thickness of the panel portions 6 and 7. When the layer of is used as the surface layer and the layer having a thickness of 25 to 50% from the surface of the panel portions 6 and 7 is used as the central layer, the average cell diameter of the central layer becomes larger than the average cell diameter of the surface layer. The ratio of (average cell diameter of the central layer) / (average cell diameter of the surface layer) is not particularly limited, but is, for example, 1.2 to 10. Specifically, this ratio is, for example, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.5, 3, It is 3.5, 4, 4.5, 5, 5.5, 6, 7, 8, 9, and 10, and may be within the range between any two of the numerical values exemplified here.

The average bubble diameter of the panel portions 6 and 7 in the thickness direction is, for example, 100 to 2000 μm. Specifically, the average bubble diameter is, for example, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1500, 2000 μm, and is between any two of the numerical values exemplified here. It may be within the range. The average cell diameter of the surface layer is, for example, 80 to 500 μm. Specifically, the average bubble diameter is, for example, 80, 100, 150, 200, 250, 300, 350, 400, 450, 500 μm, and is within the range between any two of the numerical values exemplified here. You may. The average bubble diameter of the central layer is, for example, 100 to 2000 μm. Specifically, the average cell diameter is, for example, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900. It is 2000 μm and may be within the range between any two of the numerical values exemplified here.

The average cell diameter is measured by the following method.
First, a cross-sectional photograph of the panel portions 6 and 7 is taken at a magnification of 50 times as shown in FIG.
-Next, in the cross-sectional photograph, five reference lines R1 to R5 extending in the thickness direction are drawn. The distance between the reference lines is 500 μm.
-For each reference line, count the number of bubbles passing through the reference line in the layer to be measured (surface layer, central layer, or the entire thickness direction).
-Measure the maximum length in the thickness direction (the length at the part where the length in the thickness direction is the longest) for each bubble.
-Calculate the tentative average bubble diameter for each reference line according to Equation 1. Further, the average cell diameter is calculated by arithmetically averaging the tentative average cell diameters calculated for each reference line.
(Equation 1) Temporary average bubble diameter = total maximum length of all counted bubbles / number of counted bubbles

For example, in the example of FIG. 12, the number of bubbles through which the reference line R passes in the central layer is 6, and the maximum length of each bubble in the thickness direction is L1 to L6. Therefore, in this example, the tentative average bubble diameter of the central layer is calculated by (L1 + L2 ++ L3 + L4 + L5 + L6) / 6.

The expansion step is preferably performed by executing the first suction step, the mold proximity step, and the second suction step in this order. In the first suction step, as shown in FIG. 7, the foamed resin sheet 23 is sucked under reduced pressure by the first mold 21 to shape the foamed resin sheet 23 into a shape along the cavity 21b of the first mold 21. At this time, the skin material sheet 28 is also formed together with the foamed resin sheet 23.

In the mold proximity step, as shown in FIG. 8, the molds 21 and 22 are brought close to each other so that the gap G is provided between the molds 21 and 22. In the second suction step, as shown in FIG. 9, the foamed resin sheet 23 is sucked under reduced pressure by the molds 21 and 22, so that the foamed resin sheet 23 is expanded to the thickness of the gap G. At this time, the recesses 6a, 7a, and 24d are formed in the portions corresponding to the convex portions 22b and 22e of the mold 22, and the convex portions 24c are formed in the portions corresponding to the concave portions 22d.

If decompression suction by the molds 21 and 22 is started after the molds 21 and 22 are brought close to each other, the foamed resin sheet 23 comes into contact with the convex portion 22c of the mold 22 before the foamed resin sheet 23 is formed. .. Normally, the temperature of the molds 21 and 22 is lower than the temperature of the foamed resin sheet 23. Therefore, when the foamed resin sheet 23 comes into contact with the convex portion 22c of the mold 22, the foamed resin sheet 23 is cooled and its viscosity increases. However, the followability of the molds 21 and 22 to the inner surfaces 21a and 22a deteriorates. On the other hand, when the expansion step is performed by executing the first suction step, the mold proximity step, and the second suction step in this order, the foamed resin sheet 23 has a shape along the inner surface 21a of the first mold 21. Since the contact of the foamed resin sheet 23 with the molds 21 and 22 before being shaped is minimized, the increase in the viscosity of the foamed resin sheet 23 is suppressed, and the foamed resin sheet 23 is pressed into the mold 21. , 22 can be made to follow the inner surfaces 21a, 22a with high accuracy.

(3) Finishing step After the expansion step, the molds 21 and 22 are opened, the foam molded body 24 with the burrs 23b and 28b is taken out, and the burrs 23b and 28b are cut off as shown in FIG. The foam molded product 24 shown in 1 to 4 is obtained. The skin material 3 is integrally molded on the foam molded body 24.

3.2 Press-fitting step In this step, as shown in FIGS. 1 to 4, the reinforcing member 4 is press-fitted into the recesses 6a and 7a. In one example, the reinforcing member 4 is press-fitted into the recess 6a, and then the reinforcing member 4 is press-fitted into the recess 7a while folding the left panel portion 6 and the right panel portion 7 at the hinge portion 5, as shown in FIG. , A structure 10 in which the skin material 3 is provided on both sides is obtained.

4. Other Embodiments-The skin material 3 can be omitted.
-The hinge portion 5 can be omitted.
-The panel portion may have only one recess.
-The reinforcing member 4 does not have to be exposed from the terminal 24b of the foam molded body 24.
The foam molded body 24 may be molded without expanding the foamed resin sheet 23.
-The foamed resin sheet 23 is an example of the "foamed resin parison" in the claims, and the foamed resin parison may be tubular. In this case, the cylinder may be crushed into a sheet shape.

5. Reference Example A foam molded product was produced using the foam molding machine 1 shown in FIG. The inner diameter of the cylinder 13a of the extruder 13 was 50 mm, and L / D = 34. The raw material resin is a polypropylene resin A (manufactured by Polaris AG, trade name "Daple WB140") and a polypropylene resin B (manufactured by Nippon Polypro Co., Ltd., trade name "Novatec PP / BC4BSW") in terms of mass ratio. LDPE-based master batch (manufactured by Dainichi Seika Kogyo Co., Ltd., trade name "Finecell Master P0217K") mixed at 60:40 and containing 20 wt% sodium hydrogencarbonate foaming agent as a nucleating agent with respect to 100 parts by mass of resin. ) Was added by 1.0 part by weight, and 1.0 part by weight of the LLDPE base master batch containing 40 wt% carbon black was added as a colorant. The temperature of each part was controlled so that the temperature of the foamed resin sheet 23 was 190 to 200 ° C. The rotation speed of the screw was 60 rpm, and the extrusion rate was 20 kg / hr. Blowing agent, using N ₂ gas was injected through the injector 16. The injection volume is 0.4 [wt. %] (N ₂ injection amount / resin extrusion amount). The T-die 18 was controlled so that the foamed resin sheet 23 had a thickness of 2 mm.

The foamed resin sheet 23 formed under the above conditions was placed between the molds 21 and 22. Next, the foamed resin sheet 23 was sucked under reduced pressure by the mold 21 to shape the foamed resin sheet 23 into a shape along the inner surface of the mold 21. Next, with the molds 21 and 22 close to each other so that the gap G between the molds 21 and 22 is 3 mm, the foamed resin sheet 23 is sucked under reduced pressure by the molds 21 and 22 to obtain the foamed resin. The foamed resin sheet 23 was expanded so that the thickness of the sheet 23 became the thickness of the gap G to obtain a foamed molded product 24 having a panel portion. Decompression suction by the molds 21 and 22 was performed at −0.1 MPa.

The foam molded product 24 was lighter and more rigid than a general foam molded product. A cross-sectional photograph of the panel portion of the foam molded body 24 is shown in FIG. When the average cell diameters of the surface layer and the central layer of the panel portion of the foamed molded body 24 were measured, they were 132.3 μm and 184.2 μm, respectively, and (average cell diameter of the central layer) / (average cell diameter of the surface layer). ) Was 1.39.

1: Foam molding machine 2: Resin supply device 3: Skin material 4: Reinforcing member 5: Hinge part 6: Left panel part 6a: Left concave part 6f: Front surface 6r: Back surface 7: Right panel part 7a: Right concave part 7f : Front surface 7r: Back surface 10: Structure 11: Raw material resin 12: Hopper 13: Extruder 13a: Cylinder 16: Injector 17: Accumulator 17a: Cylinder 17b: Piston 18: T-die 21: First mold 21a: Inner surface 21b: Cavity 21d: Pinch-off part 22: Second mold 22a: Inner surface 22b: Convex part 22c: Convex part 22d: Concave part 22e: Convex part 23: Foamed resin sheet 23a: Part 23b: Burr 24: Foam molded body 24a: Side surface 24b: Terminal 24c: Convex part 24d: Concave part 25: Connecting pipe 27: Connecting pipe 28: Skin material sheet 28a: Part 28b: Bali G: Gap S: Sealed space

Claims (2)

A method for manufacturing a structure, which includes a molding process and a press-fitting process.
In the molding step, a foamed resin parison is molded to form a foamed molded product having a panel portion.
The panel portion is provided with a back surface and a front surface facing each other, and the back surface is provided with a recess.
In the press-fitting step, a reinforcing member is press-fitted into the recess.
The panel portion includes a left panel portion and a right panel portion.
The left panel portion and the right panel portion are rotatably connected to each other by a hinge portion.
The hinge portion is formed by compressing the foamed resin parison with the first and second molds.
In the molding step, a method for manufacturing a structure, in which a skin material straddling the left panel portion, the hinge portion, and the right panel portion is integrally molded with the foam molded body on the front surface side. The molding step includes a placement step and an expansion step.
The foamed resin parison is a single foamed resin sheet.
In the arrangement step, the foamed resin sheet is arranged between the first and second molds, and the foamed resin sheet is arranged between the first and second molds.
In the expansion step, the first and second molds are brought close to each other so that a gap larger than the thickness of the foamed resin sheet is provided between the first and second molds. The method for manufacturing a structure according to claim 1, wherein the foamed resin sheet is expanded to the thickness of the gap by sucking the foamed resin sheet under reduced pressure by both.

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