JP5834797B2 - Manufacturing method of hollow thin panel structure made of bendable or bendable resin - Google Patents

Description

  The present invention relates to a method of manufacturing a hollow thin panel structure made of a bendable or bendable resin, and more specifically, a bend capable of preventing an increase in molding cost or a decrease in molding efficiency while ensuring good moldability. The present invention relates to a method for manufacturing a hollow thin panel structure made of freely or bendable resin.

Conventionally, bendable or bendable hollow thin panel structures have been used in various fields such as automobile interior parts, foldable curtains, and folding beds.
This hollow thin panel structure has a rectangular shape and has a plurality of hinge portions that can rotate around the long side or short side direction, and can be bent or bent around the hinge portion. From the viewpoint of processability, a resin-made integrated structure is employed.
For example, Patent Literature 1 and Patent Literature 2 disclose a hollow thin panel structure by such resin integral molding.

  According to Patent Document 1, a hinge structure of a resin molded product applied to an automobile interior part is disclosed, and this hinge structure is laminated on a sheet material of fiber reinforced thermoplastic resin and one or both surfaces of the sheet material. The skin material is integrally formed, and a hinge portion is formed on the back surface of the sheet material by providing a plurality of long grooves at predetermined intervals in the longitudinal direction of the sheet material. Although this hinge structure is integrally formed, it is not disclosed how to form a plurality of long grooves, is a solid hinge structure, and does not have a hollow portion, so that the weight increases accordingly.

In this regard, according to Patent Document 2, a hollow hinge structure is disclosed.
According to Patent Document 2, several kinds of floorboard hinge structures for a tiltable bed are disclosed. A certain hinge structure is an integrally molded product by blow molding, and a reinforcing rib extending in the floorboard width direction is provided at each bent portion. A thin hinge extending in the floor plate width direction is provided on both sides of the reinforcing rib. Another hinge structure is an integrally molded product by injection molding, and is provided with a bent portion made of a bellows-like hinge extending in the floor plate width direction.

  According to these hinge structures, unlike a general hinge structure composed of a combination of a hinge holder and a hinge shaft, a hinge portion is formed simply by partially reducing the plate thickness, so that blow molding or injection molding is used. While forming by integral molding, it is possible to achieve cost reduction by reducing the number of parts.

  In particular, according to blow molding, unlike injection molding, a hollow structure can be molded. However, the following technical problems exist because thinning is required.

First, using a molten cylindrical thermoplastic resin sheet, for example, a molten cylindrical thermoplastic resin is placed between a pair of mold dies and blown pressure is applied into a sealed space formed by clamping. If an attempt is made to press the manufactured sheet against the mold, the thinner the hollow structure becomes, the more difficult it becomes to form.
More specifically, before applying the blowing pressure, it is necessary to maintain a sealed space so that the peripheral inner surfaces of the molten cylindrical thermoplastic resin sheets do not stick to each other. This becomes more difficult.
In general, in the case of blow molding, depending on the width of the panel to be molded and the characteristics of the resin to be used, when the thickness of the hollow portion is 10 mm or less, using a molten cylindrical thermoplastic resin sheet, It becomes difficult to form the hollow portion by blowing.
In particular, in a thin hollow structure, if the opposing panel members are locally butted together and a hinge portion is provided at this butted portion, blow molding becomes more difficult as the interval between adjacent hinge portions becomes narrower. It becomes difficult to ensure the degree of freedom of bending or bending by the part.

Second, it causes an increase in molding cost or a decrease in molding efficiency.
More specifically, as described above, in the thin hollow structure, if the hinge portion is provided by locally abutting the opposing panel members, the hollow portion is divided, so that the hollow is divided. For each part, it is necessary to pierce the blow pin in order to apply the blowing pressure, and this complicated operation causes an increase in molding cost or a reduction in molding efficiency. In addition, if the hole formed by the blow pin is left as it is, the appearance of the hole may be damaged depending on the position of the hole, and furthermore, the molded product does not become a sealed space, so the compression force is applied to the molded product. May be easily deformed when this occurs, and if the hole is closed to prevent such a problem, an extra work is required.
JP-A-10-299319 JP 2002-102015

  In view of the above technical problems, the object of the present invention is to be able to bend or bend a resin-made hollow thin panel structure capable of preventing an increase in molding cost or a decrease in molding efficiency while ensuring good moldability. It is in providing the manufacturing method of.

In order to achieve the above object, a method for producing a resin hollow thin panel structure of the present invention comprises:
A method of manufacturing a hollow thin panel structure made of a resin that can be bent or bent, having a hinge part,
A pair of split molds, each having a pinch-off portion around each cavity, arranged opposite to each other, and movable relative to each other between a clamping position and an open position, and at least one split mold Each of which has a pair of protrusions extending over a predetermined length so as to define a cavity and having a tapered shape toward the other split mold and spaced apart from each other by a predetermined distance. Preparing the split mold,
Disposing each of the two thermoplastic resin sheets in a molten state at a distance from each other and protruding from a corresponding pinch-off portion, and placing between a pair of split molds in an open position;
A sealed space is formed between the at least one divided mold and the corresponding thermoplastic resin sheet, and air is decompressed from the sealed space, so that the thermoplastic resin sheet is sucked into the cavity. The thermoplastic sheet is formed with a tapered protrusion that extends toward the inner surface of the other thermoplastic resin sheet so as to form a plurality of long grooves on the outer surface facing the cavity. Forming a plurality at intervals of
The pair of split molds are moved to the mold clamping position, and the inner surfaces of the two thermoplastic resin sheets are welded along the pinch-off portions of the pair of molds, thereby making two strips of thermoplastic resin. Integrating the peripheral edges of the sheet to form a hollow structure, and abutting and welding each tip of the plurality of tapered protrusions to the inner surface of the other thermoplastic resin sheet,
As a result, a hinge portion that can be rotated around the extending direction of the corresponding tapered protrusion is formed in the abutting portion, and the plurality of tapered protrusions as a whole can be bent or bent.

According to the manufacturing method of the hollow thin panel structure made of a bendable or bendable resin having the hinge part having the above-described configuration, the peripheral parts of the two thermoplastic resin sheets are integrated to form a hollow structure. At the same time, a plurality of tapered protrusions are formed on one thermoplastic resin sheet, and the tip of the tapered protrusion is butt-welded to the inner surface of the other thermoplastic resin sheet to locally bond the hinge portion. By forming it, it is possible to manufacture a resin hollow thin panel structure that can be bent or bent as a whole of the plurality of tapered protrusions.
In this case, since the two thermoplastic resin sheets in a melted state at a predetermined interval are used and molded only by suction without applying blowing pressure, a good moldability can be obtained while being a thin hollow structure. It can be secured. More specifically, for example, if a molten cylindrical thermoplastic resin sheet is placed between a pair of split molds and blown pressure is applied into a sealed space formed by clamping, the blowing pressure is reduced. It is necessary to maintain a state in which a sealed space is formed so that the peripheral inner surfaces of the cylindrical thermoplastic resin sheets do not stick together before being applied, but this becomes more difficult as the thin hollow structure is formed. On the other hand, by using two thermoplastic resin sheets in a melted state at a predetermined interval, at least one of the thermoplastic resin sheets is sucked and molded before mold clamping. It is also possible to set the interval between adjacent hinges freely, and to secure the degree of freedom of bending or bending by the hinges, while thin hollow Since the structure is molded, the height of the plurality of protrusions provided on at least one of the divided molds is not required so much, and it is possible to ensure good moldability without causing a high blow ratio.

Furthermore, the hollow portion of the thin hollow structure is divided by butt welding each tip end portion of the plurality of tapered projecting portions to the inner surface of the other thermoplastic resin sheet. Then, it is necessary to pierce and mold the blow pin for each hollow part to be divided, but such a complicated operation is unnecessary and a parting line between two thermoplastic resin sheets is formed. Since post-processing is not required to ensure aesthetic appearance on the peripheral side surface, it is possible to prevent molding costs from increasing or molding efficiency from decreasing, and as a whole, molding costs are increased or molded while ensuring good moldability. It is possible to prevent a decrease in efficiency.

The hinge portion may be formed so as to be rotatable at the abutting portion by thinning the solid portion.
Furthermore, it is preferable that suction holes are provided in the cavities between at least the plurality of protrusions, and the thermoplastic resin sheet is sucked and shaped. Furthermore, it is preferable that at least one suction hole is provided in each of the cavities partitioned by the plurality of protrusions and the cavity between the plurality of protrusions, and the thermoplastic resin sheet is sucked and shaped.

In addition, one plate material of the resin first plate material and the resin second plate material has a flat plate shape, a decorative material is attached to the outer surface thereof, and the other plate material has the plurality of tapered protrusions. Should be formed.
Further, the one and / or the other thermoplastic resin sheet may be preformed in advance and reheated into a molten state.
Furthermore, before the decompression step, a decorative material is disposed at a predetermined position of the cavity of the other mold,
In the mold clamping step, the decorative material may be welded to the outer surface of the other thermoplastic resin sheet.

In addition, the depressurizing step includes a step of moving an outer frame that is externally fitted to a peripheral edge of the at least one divided mold so as to be movable in a mold clamping direction toward an outer surface of the corresponding thermoplastic resin sheet. It is preferable that a sealed space is formed by the outer surface of the corresponding thermoplastic resin sheet, the inner peripheral surface of the outer frame, and the respective cavities of the pair of split molds.
Furthermore, it is preferable to have a step of extruding between the pair of split molds in such a manner that the one and the other molten thermoplastic resin sheets are suspended downward.

An embodiment of a method for producing a resin hollow thin panel structure according to the present invention will be described in detail below with reference to the drawings, taking the floor plate 10 of a tiltable bed as an example of the resin hollow thin panel structure.
The tilting bed is used as a nursing bed, for example, and is tiltable so that it can be rotated between a lying position (solid line in FIG. 3) and a standing position (dotted line in FIG. 3). Is provided with a hinge portion 13 extending over the entire width direction of the floor plate.

More specifically, as shown in FIGS. 1 to 3, the floor board 10 has a resin hollow thin panel structure, and includes a resin first board material 14 and a resin second board material 16 that face each other. The peripheral portions of the plate members 14 and 16 are welded together to form a hollow portion 18 therein.
The thickness of each of the first resin plate 14 and the second resin plate 16 is appropriately determined in relation to the resin material from the viewpoint that the weight of the bed user can be sufficiently supported as the floor plate 10 of the tiltable bed. That's fine.

The floor board 10 is configured to be bendable at two places with a predetermined interval in the longitudinal direction, and is divided into three floor board portions 22A, 22B, 22C, with each of the bent places 20A, B as a boundary. The floor plate portions 22A, B, and C form a hollow portion 18 independently of each other.
The distance D between the inner surface 21 of the first resin plate 14 and the inner surface 23 of the second resin plate 16 is not more than three times the thickness T of each of the first resin plate 14 and the second resin plate 16. The distance between the inner surface 21 of the first resin plate 14 and the inner surface 23 of the second resin plate 16 is, for example, 10 mm or less, preferably 3 mm or less. Even if it is such a thin shape, according to the manufacturing method using the suction molding described later, it is possible to integrally form the hinge portion 13 and the like.

  As shown in FIG. 2, the first resin plate 14 has a flat plate shape, whereas the second resin plate 16 differs from the first resin plate 14 in the bent portions 20A and 20B. Four tapered protrusions 28 extending toward the inner surface 21 of the first resin plate 14 are provided at predetermined intervals in the longitudinal direction of the floor board 10 so as to form four long grooves 26. As a result, four reinforcing ribs 24 are formed in each bent portion 20, and each reinforcing rib 24 extends over the entire width of the floor board.

More specifically, each taper protrusion 28 extends over the entire width direction (direction perpendicular to the longitudinal direction) of the floor board 10, and a resin-made first plate material is provided at each tip of the taper protrusion 28. 14 is provided with an abutting portion 30 to be abutted and welded to the inner surface 21.
Each of the tapered protrusions 28 has a pair of inclined surfaces 32 that are opposed to each other and are inclined with respect to the second resin plate 16 provided with the tapered protrusions 28, and the second resin plate of the pair of inclined surfaces 32. The interval between the edge portions on the 16 side constitutes the width in the longitudinal direction of the floor plate 10 of the abutting portion 30.
Each of the plurality of long grooves 26 has a trapezoidal cross-sectional shape, the inclination angle α of the inclined surface 32 (FIG. 2), the number of the tapered protrusions 28, the interval D (FIG. 2) between the adjacent tapered protrusions 28, and the butting The longitudinal width W (FIG. 2) of the floor plate 10 of the portion 30 is determined from the viewpoint that the tiltable bed can rotate between the lying position and the standing position at each of the bent portions 20A and 20B. do it.

More specifically, each of the four tapered protrusions 28 is formed with a hinge portion 13 that can rotate around the width direction of the floor board 10, and the four tapered protrusions 28 as a whole can be bent or bent. The
In particular, as shown in FIG. 3, the resin-made second plate 16 can be bent in such a manner that the openings 25 of the plurality of long grooves 26 are expanded by arranging the openings 25 of the plurality of long grooves 26 on the back surface side of the floor plate 10. It is possible to ensure the degree of freedom of bending. In addition, since each abutting part 30 forms the hinge part 13 which can rotate around the width direction of the floor board 10, the width W of the longitudinal direction of the floor board 10 of the abutting part 30 is the resin 2nd board | plate material 16. It is preferable that the abutting portion 30 extends linearly in the width direction of the floor board 10 within a range where it is welded and fixed to the first resin plate 14 via the abutting portion 30. Thereby, each hinge part 13 is formed so that it can rotate in the corresponding butting | matching part 30 by making it solid thin.
It should be noted that a structure similar to the reinforcing rib 24 may be appropriately provided in the hollow portion 18 at portions other than the bent portions 20A and B, thereby ensuring the compressive strength of the floor board 10.

  The material of each of the resin first plate member 14 and the resin second plate member 16 is a thermoplastic resin, such as an olefin resin such as polyethylene or polypropylene, or an amorphous resin, and more specifically ethylene, propylene, It is a polyolefin (for example, polypropylene or high density polyethylene) which is a homopolymer or copolymer of olefins such as butene, isoprenepentene and methylpentene.

Next, an apparatus and a method for forming a floor board having a resin hollow thin panel structure having the above-described structure using a mold will be described.
As shown in FIG. 4, the molding device 60 having a resin hollow thin panel structure includes an extrusion device 62 and a mold clamping device 64 disposed below the extrusion device 62, and the melt extruded from the extrusion device 62. The thermoplastic resin sheet P in a state is sent to the mold clamping device 64, and the molten thermoplastic resin sheet P is molded by the mold clamping device 64.

  The extruding device 62 is a conventionally known type, and detailed description thereof is omitted. However, a cylinder 66 provided with a hopper 65, a screw (not shown) provided in the cylinder 66, and a screw are connected to the screw. A hydraulic motor 68, an accumulator 70 communicating with the inside of the cylinder 66, and a plunger 72 provided in the accumulator 70, and resin pellets introduced from the hopper 65 are screwed by the hydraulic motor 68 in the cylinder 66. The molten resin is melted and kneaded by the rotation of the resin, and the molten resin is transferred to the accumulator chamber and stored in a certain amount. The plunger 72 is driven to feed the molten resin toward the T die 71 and continuously through the die slit (not shown). A sheet-like thermoplastic resin sheet P is extruded and arranged at intervals. It is suspended during the while being clamped sent out downward split mold 73 by the rollers 79. Thereby, the sheet-like thermoplastic resin sheet P is disposed between the split molds 73 in a stretched state without wrinkles or slack.

The extrusion capability of the extrusion device 62 is appropriately selected from the viewpoints of the size of the first resin plate 14 and the second resin plate 16 to be molded, and the prevention of the drawdown of the thermoplastic resin sheet P. More specifically, from a practical viewpoint, the extrusion rate of the resin from the die slit is several hundred kg / hour or more, more preferably 700 kg / hour or more. Further, from the viewpoint of preventing the drawdown of the thermoplastic resin sheet P, the extrusion process of the thermoplastic resin sheet P is preferably as short as possible, and generally depends on the type of resin and the MFR value. Should be completed within 40 seconds, more preferably within 30 seconds. For this reason, the extrusion area per unit area and unit time of the thermoplastic resin from the die slit is 50 kg / hour cm ² or more, more preferably 60 kg / hour cm ² or more.

  The die slit 75 is arranged vertically downward, and the thermoplastic resin sheet P pushed out from the die slit 75 is sent vertically downward in a form that hangs down from the die slit 75 as it is. The die slit can change the thickness of the continuous sheet-like thermoplastic resin sheet P by making the width variable.

  On the other hand, the mold clamping device 64 is also a conventionally known type like the extrusion device 62, and detailed description thereof will be omitted. However, two divided molds 73 and a sheet-like heat in which the mold 73 is melted are used. A mold driving device that moves between an open position and a closed position in a direction substantially orthogonal to the supply direction of the plastic resin sheet P;

  The two divided molds 73 are arranged with the cavities 74 facing each other, and are arranged so that the cavities 74 are directed substantially in the vertical direction. The surface of each cavity 74 has irregularities according to the outer shape and surface shape of the first resin plate 14 and the second resin plate 16 formed on the basis of the molten sheet-like thermoplastic resin sheet P. Is provided.

  In each of the two divided molds 73, a pinch-off portion 76 is formed around the cavity 74. The pinch-off portion 76 is formed in an annular shape around the cavity 74 and protrudes toward the opposing mold 73. To do. As a result, when the two divided molds 73 are clamped, the tip portions of the respective pinch-off portions 76 come into contact with each other, so that the parting line PL is formed at the periphery of the molten thermoplastic resin sheet P. I have to.

Each of the divided molds 73A extends over a predetermined length so as to define a cavity 74A, has a tapered shape toward the other divided mold 73B, and is spaced apart from each other by a predetermined distance. Two protrusions 80 are provided on the upper and lower portions of the cavity 74A. With such a shape, the thermoplastic resin sheet P <b> 1 formed by the protrusion 80 can be easily detached from the protrusion 80 when the mold described later is opened.
More specifically, each protrusion 80 has a trapezoidal cross section, extends in the horizontal direction, and the width of the upper base constitutes the width of the abutting portion 30. The height of each protrusion 80 is such that the protrusion of the mold 73A is when the pinch-off portion 76A of the mold 73A and 76B of the mold 73B are abutted when the divided mold 73 to be described later is clamped. The height is such that the thermoplastic resin sheet P1 formed by the body 80, particularly the butting portion 30, is sufficiently welded to the inner surface of the thermoplastic resin sheet P2 formed by the mold 73B.

  A mold 81 is slidably fitted around the outer periphery of the divided mold 73A, and the mold 81 can be moved relative to the mold 73A by a mold moving device (not shown). More specifically, the mold 81 can contact one side 83 of the thermoplastic resin sheet P1 disposed between the molds 73 by projecting toward the mold 73B with respect to the mold 73A. It is.

  As shown in FIG. 6, a vacuum suction chamber 85 is provided inside the split mold 73 </ b> A. The vacuum suction chamber 85 communicates with the cavity 74 </ b> A through the suction hole 87, and the suction hole 87 extends from the vacuum suction chamber 85. The sheet P1 made of thermoplastic resin is adsorbed toward the cavity 74A, and is shaped into a shape along the outer surface of the cavity 74A. At least one suction hole 87 is provided in each of the cavities 74A defined by the protrusions and each of the cavities 74C between the plurality of protrusions.

  The mold driving device is the same as the conventional one, and the description thereof is omitted. However, the two divided molds 73 are each driven by the mold driving device, and in the open position, the two divided molds are used. 73, two continuous sheet-like thermoplastic resin sheets P1 and 2 in a molten state can be arranged with a space between each other, and in one closed position, the pinch-off portions of the two split molds 73 76 abuts and the annular pinch-off portions 76 abut each other so that a sealed space is formed in the two split molds 73. In addition, about the movement of each metal mold | die 73 from an open position to a closed position, a closed position is made into the position of the centerline of the continuous sheet-like thermoplastic resin sheet | seats P1 and 2 of the 2 sheet | seat melt state, It is driven by the mold driving device so as to move toward the position.

Next, a method for forming a resin hollow thin panel structure using the above-described forming apparatus will be described.
First, as shown in FIG. 4, the thermoplastic resin sheets P1 and P2 made of molten thermoplastic resin are extruded vertically downward from the corresponding die slits 75 to form two continuous sheet-like thermoplastic resin sheets P1, 2 is supplied between the two split molds 73 in a form protruding from the corresponding pinch-off portions 76.

  Next, as shown in FIG. 5, the mold frame 81 of the split mold 73A is moved toward the thermoplastic resin sheet P1 with respect to the split mold 73A so as to contact the side surface 83 of the thermoplastic resin sheet P1. Make contact. Thereby, a sealed space 84 is formed by the side surface 83 of the thermoplastic resin sheet P1, the inner peripheral surface of the mold 810, and the cavity 73A.

  Next, as shown in FIG. 6, by sucking the air in the sealed space 84 from the vacuum suction chamber 85 through the suction hole 87, the thermoplastic resin sheet P1 is adsorbed to the cavity 74A, thereby The thermoplastic resin sheet P1 is shaped into a shape along the surface of the cavity 74A. More specifically, the protrusions 80 of the cavities 74A form the long grooves 26 complementary to the protrusions 80 from the surface facing the cavity 74A of the thermoplastic resin sheet P1 toward the opposite surface. Thereby, on the opposite surface, four tapered protrusions 28 are formed in each of the upper part and the lower part of the thermoplastic resin sheet P1 to form the foundation of the hinge part 13 and the peripheral wall.

  Next, as shown in FIG. 7, each annular shape is held in a state in which the thermoplastic resin sheet P <b> 1 is sucked and held in a state where the mold 81 that contacts the outer surface 83 of the thermoplastic resin sheet P <b> 1 is held as it is. The molds 73A and 73B are moved toward each other until the pinch-off portions 76A and B come into contact with each other, and the molds are clamped. Accordingly, the peripheral portions of the two thermoplastic resin sheets P1 and P2 are integrated with each other to form a hollow structure, and the distal ends of the plurality of tapered protrusions 28 are formed on the thermoplastic resin sheet P2. The inner surface is abutted and welded, thereby forming a hinge portion 13 that can be rotated around the extending direction of the corresponding tapered protrusion 28 in each of the abutting portions 30, and the plurality of tapered protrusions 28 as a whole are curved. Alternatively, it can be bent freely.

Next, as shown in FIG. 8, the two split molds 73 are opened, the cavities 74 are separated from the completed resin hollow thin panel structure, and burrs formed around the parting line PL are removed.
This completes the molding of the floor plate having a resin hollow thin panel structure.

  As described above, the resin hollow thin panel structure can be formed one after another by repeating the above steps each time the molten thermoplastic resin is intermittently extruded. It is possible to intermittently extrude the thermoplastic resin sheets P1 and P2 in a molten state by molding, and shape the extruded thermoplastic resin sheets P1 and P2 into a predetermined shape using a mold 73.

  According to the method of manufacturing a hollow thin panel structure made of a bendable or bendable resin having the hinge portion 13 having the above configuration, the peripheral portions of the two thermoplastic resin sheets P1, P2 are integrated with each other, In addition to forming a hollow structure, a plurality of tapered protrusions 28 are formed on one thermoplastic resin sheet P1, P2, and the tip of the tapered protrusion 28 is formed on the inner surface of the other thermoplastic resin sheet P1, P2. By forming the hinge portion 13 locally by butt welding, it is possible to manufacture a resin hollow thin panel structure that can be bent or bent as a whole of the plurality of tapered protrusion portions 28.

In this case, since the two thermoplastic resin sheets P1 and P2 in a molten state separated by a predetermined interval are formed by suction only without applying the blowing pressure, the thin hollow structure is satisfactory. Formability can be ensured. More specifically, for example, if the molten cylindrical thermoplastic resin sheets P1 and P2 are arranged between a pair of split molds 73 and blown pressure is applied to the sealed space formed by clamping, the molding is performed. Before applying the blowing pressure, it is necessary to maintain a sealed space so that the inner peripheral surfaces of the cylindrical thermoplastic resin sheets P1 and P2 do not stick together. Will be difficult. In contrast, at least one of the thermoplastic resin sheets P1 and P2 is sucked and molded before mold clamping by using the two molten thermoplastic resin sheets P1 and P2 at a predetermined interval. Thus, such technical problems can be solved and the interval between the adjacent hinge portions 13 can be set freely, thereby ensuring the degree of freedom of bending or bending by the hinge portions 13. On the other hand, since the thin hollow structure is molded, the height of the plurality of protrusions provided on at least one of the divided molds 73 is not so required, and a high blow ratio is not generated, and good moldability is achieved. It is possible to secure.
Furthermore, the hollow portion 18 of the thin hollow structure is divided by butt welding each tip end of the plurality of tapered projecting portions 28 to the inner surface of the other thermoplastic resin sheet P1, P2, so that the blowing pressure is reduced. If it is going to be molded, it is necessary to pierce and mold each blown hollow portion 18, but such a complicated operation is not necessary, and the appearance is beautiful due to the holes formed by the blow pins. It is possible to eliminate the trouble of easily deteriorating or easily deforming, and further to eliminate the trouble of plugging the hole to prevent such trouble, and in addition, it is made of two thermoplastic resins. No post-processing is required to ensure the aesthetic appearance on the peripheral side surface where the parting lines between the sheets P1 and P2 are formed, thus preventing an increase in molding cost or a reduction in molding efficiency. In general, it is possible to prevent an increase in molding cost or a decrease in molding efficiency while ensuring good moldability.

As a modification, when a resin hollow thin panel structure is used as an automobile interior, a decorative material may be attached to the outer surface of either the resin first plate member or the resin second plate member.
The decorative material is provided from the viewpoint of improving the appearance and the decorativeness, and the material is a fiber skin material sheet-like skin material, a film-like skin material, or the like. As a material of such a fiber skin material, synthetic fibers such as polyester, polypropylene, polyamide, polyurethane, acrylic and vinylon, semi-synthetic fibers such as acetate and rayon, regenerated fibers such as viscose rayon and copper ammonia rayon, cotton, hemp, Examples thereof include natural fibers such as wool and silk, or blended fibers thereof.

In this case, since the interior of the automobile secures the maximum space in the vehicle, the decorative material is pasted, so that further reduction in thickness is required as compared with the folding bed of the embodiment. The distance D between the inner surface 21 of the first resin plate 14 and the inner surface 23 of the second resin plate 16 is the thickness T of each of the first resin plate 14 and the second resin plate 16 as in the embodiment. The distance between the inner surface 21 of the resin first plate member 14 and the inner surface 23 of the resin second plate member 16 is, for example, 3 mm or less.
The decorative material is preferably affixed to the surface of the first resin plate that is not provided with a plurality of long grooves on the surface.
When molding such an automobile interior product, the decorative material is placed at a predetermined position in the cavity of the other mold 73 before the decompression step, so that the decorative material is It is welded to the outer surface of the thermoplastic resin sheets P1, P2. In addition, by disposing the decorative material in a form that protrudes from the pinch-off portion, the decorative material can be formed so as to extend to the peripheral portion of the automobile interior part, thereby further improving the appearance or decoration.

The embodiments of the present invention have been described in detail above, but various modifications or changes can be made by those skilled in the art without departing from the scope of the present invention.
For example, in the present embodiment, the thermoplastic resin sheets P1 and P2 in a molten state extruded from the extrusion slit are directly molded. However, the present invention is not limited thereto, and one and / or the other thermoplastic resin sheet is formed. P1 and P2 may be preformed in advance and reheated into a molten state.
In this embodiment, the hinge 13 is formed on the resin sunshade by the tapered protrusion 28 protruding from the resin second plate 16 toward the inner surface of the resin first plate 14. However, the present invention is not limited thereto, and a tapered projecting portion 28 projecting from each of the resin first plate member 14 and the resin second plate member 16 toward the hollow portion 18 is provided, and the respective butted portions 30 are disposed in the hollow portion 18. It may be formed by welding.
Moreover, although the embodiment demonstrated the case where it bent or bent in the hinge part 13, you may utilize as a case where it curves in the hinge part 13, without being limited to it. In such a case, unlike the case of bending or bending by one hinge portion 13, a plurality of hinge portions 13 are provided adjacent to each other in the longitudinal direction, and the plurality of hinge portions 13 form a curved portion as a whole. From the viewpoint of balancing the compressive strength and the degree of freedom of bending, it is preferable to determine the height of the reinforcing rib 24, the angle of the inclined surface 32, and the width of the butted portion 30.

1 is a schematic perspective view of a tiltable bed according to an embodiment of the present invention. FIG. 2 is a sectional view taken along line AA in FIG. 1. It is a figure which shows the state which exists in a fall position and a standing position in the tilting-type bed which concerns on embodiment of this invention. The outline of the apparatus for forming a floor board of a tiltable bed according to an embodiment of the present invention is shown, and in the molding process of the floor board of the tiltable bed according to an embodiment of the present invention, the thermoplastic resin sheets P1, P2 are divided. It is a figure which shows the state arrange | positioned between the metal mold | dies 73 of a format. FIG. 5 is a schematic side view showing a state in which the mold of the split mold is brought into contact with the side surface of the thermoplastic resin sheet P1 in the step of forming the floor plate of the tiltable bed according to the embodiment of the present invention. FIG. 3 is a schematic partial cross-sectional view showing a state in which a thermoplastic resin sheet P1 is shaped in a molding process of a floorboard of a tiltable bed according to an embodiment of the present invention. It is a figure which shows the state which clamped the division mold in the formation process of the floor board of the raising / lowering type bed which concerns on embodiment of this invention. It is a figure which shows the state which open | released the split mold in the formation process of the floor board of the raising / lowering bed which concerns on embodiment of this invention.

P Thermoplastic resin sheet PL Parting line α Inclination angle 10 Floor plate 13 Hinge portion 14 Thermoplastic resin first plate material 16 Thermoplastic resin second plate material 18 Hollow portion 20 Bending portion 22 Floor plate portion 23 Inner surface 24 Reinforcement rib 26 Long groove 28 Tapering protrusion 30 Abutting part 32 Inclined surface 60 Molding device 62 of resin hollow thin panel structure Extruding device 64 Clamping device 65 Hopper 66 Cylinder 68 Hydraulic motor 70 Accumulator 72 Plunger 73 Mold 74 Cavity 75 Die slit 76 Pinch off Portion 80 Projection body 81 Form 85 Vacuum suction chamber 87 Suction hole

Claims (9)

A method for producing a bendable resin hollow thin panel structure having a hinge portion,
A pair of split molds, each having a pinch-off portion around each cavity, arranged opposite to each other, and movable relative to each other between a clamping position and an open position, and at least one split mold Each extends over a predetermined length to define a cavity,
Preparing a pair of split molds having a tapered shape toward the other split mold and provided with a plurality of protrusions spaced apart from each other;
Disposing each of the two thermoplastic resin sheets in a molten state at a distance from each other and protruding from a corresponding pinch-off portion, and placing between a pair of split molds in an open position;
A sealed space is formed between the at least one divided mold and the corresponding thermoplastic resin sheet, and air is decompressed from the sealed space, so that the thermoplastic resin sheet is sucked into the cavity. The thermoplastic sheet is formed with a tapered protrusion that extends toward the inner surface of the other thermoplastic resin sheet so as to form a plurality of long grooves on the outer surface facing the cavity. Forming a plurality at intervals of
The pair of split molds are moved to the mold clamping position, and the inner surfaces of the two thermoplastic resin sheets are welded along the pinch-off portions of the pair of molds, thereby making two strips of thermoplastic resin. Integrating the peripheral edges of the sheet to form a hollow structure, and abutting and welding each tip of the plurality of tapered protrusions to the inner surface of the other thermoplastic resin sheet, Thereby, in the abutting portion, a hinge portion that is rotatable around the extending direction of the corresponding tapered protruding portion is formed,
The predetermined distance between the tapered protrusions and the width of the abutting part are set so that the plurality of tapered protrusions can be bent as a whole in cooperation with each other, and the hinge part is spaced apart from the predetermined distance. A method for producing a resin-made hollow thin panel structure, comprising three or more of the tapered protrusions provided . The said hinge part is a manufacturing method of the resin-made hollow thin panel structure of Claim 1 formed so that it can rotate by thinning a solid in the said abutting part. The method for producing a resin-made hollow thin panel structure according to claim 1, wherein suction holes are provided in cavities between at least a plurality of protrusions and a thermoplastic resin sheet is sucked and shaped. At least one suction hole is provided in each of the cavities defined by the plurality of protrusions and the cavity between the plurality of protrusions, and the thermoplastic resin sheet is sucked and shaped.
The manufacturing method of the resin-made hollow thin panel structure of Claim 1. One plate member of the first resin plate member and the second resin plate member has a flat plate shape, a decorative material is attached to the outer surface thereof, and the plurality of tapered protrusions are formed on the other plate member. The manufacturing method of the resin-made hollow thin panel structure of Claim 2. The method for producing a resin hollow thin panel structure according to claim 1, wherein the one and / or the other thermoplastic resin sheet is preformed in advance and reheated to be in a molten state. Before the decompression step, a decorative material is disposed at a predetermined position of the cavity of the other mold,
The method for producing a resin hollow thin panel structure according to claim 1, wherein, in the mold clamping step, the decorative material is welded to the outer surface of the other thermoplastic resin sheet. The depressurization step includes a step of moving an outer frame that is externally fitted to a peripheral edge of the at least one split mold so as to be movable in a mold clamping direction toward an outer surface of a corresponding thermoplastic resin sheet, 2. The resin-made hollow thin panel structure according to claim 1, wherein a sealed space is constituted by the outer surface of the corresponding thermoplastic resin sheet, the inner peripheral surface of the outer frame, and the respective cavities of the pair of split molds. Production method. 2. The resin hollow thin panel structure according to claim 1, further comprising a step of extruding the one and the other molten thermoplastic resin sheet downwardly between the pair of split molds. Manufacturing method.

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