JP3751078B2 - Hollow double wall molded article and method for producing the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hollow double wall molded article made of a thermoplastic resin having front and back walls opposed to each other at an interval and whose peripheral edges are closed by end walls, and a method for producing the same.
[0002]
[Prior art]
Conventionally, as a method for manufacturing a hollow plate made of a thermoplastic resin having a front wall and a back wall facing each other and having excellent mechanical strength such as rigidity, there is a method described below.
[0003]
As shown in FIG. 6 (a), the molds 121 and 122 in a divided form are opened, and the reinforcing core material 103 is set on a holder 123 that is disposed in one mold 122 so as to be freely advanced and retracted. After the Paris 114 is placed between the molds 121 and 122, the mold is closed, and then a pressurized fluid is supplied into the Paris 114 and blow-molded along the surface of the cavity and the reinforcing core 103. in the course of blow molding as shown in (b) of FIG. 6, the distal end of the retainer 123 is retracted so that the cavity surface and the same surface of the die 122, the reinforcing core member 103 is internally provided A method of manufacturing the hollow plate body 101 provided with the inner rib 102 that cannot be seen from the outside (see Japanese Patent Publication No. 61-21125).
[0004]
[Problems to be solved by the invention]
However, in the above-described conventional technique, deformation such as warpage occurs in the hollow plate due to the difference in expansion and contraction caused by the difference in thermal expansion coefficient between the reinforcing core material and the base resin. Further, in order to join the hollow plate body and the other member, it is necessary to form a locking portion or a fixing portion for joining the other member to the hollow plate body by post-processing or the like. There is a problem that the formed locking portion and fixing portion are inferior in the bonding strength and durability with the hollow plate body itself.
[0005]
The present invention has been made in view of the above-described problems of the prior art, and is free from deformation such as warpage, and has a locking portion and a fixing portion excellent in bond strength and durability. An object of the present invention is to realize a double wall molded article and a method for producing the same.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, a first hollow double-wall molded product of the present invention has an interior of a hollow body having front and back walls facing each other at an interval and whose peripheral edges are closed by end walls. Further, one end side is welded to the back surface of the front wall and the other end side is a hollow double wall molded product having an inner rib integrally formed on the back wall, and the inner rib has a longitudinal direction thereof. The extending embedded member is embedded, and the end of the embedded member protrudes from the outer surface of the end wall.
[0007]
The method for producing a hollow double-wall molded article according to the present invention is the method for producing a hollow double-wall molded article according to claim 1, wherein the front wall forming cavity surface for regulating the outer surface of the front wall and the front wall are provided. One mold having a cavity having an end wall forming cavity surface that surrounds the forming cavity surface and regulates a part of the outer surface in the height direction of the end wall, and a back wall forming cavity that regulates the outer surface of the back wall And the other mold having a cavity having a cavity surface for forming an end wall that surrounds the surface and the cavity surface for forming the back wall and regulates the remaining portion in the height direction of the end wall, and opens the end of the embedded member In a suspended state so that the projecting portion and the front end surface of the embedded member are substantially flush with each other by inserting the portion into a holding groove provided in the projecting portion projecting from the mating surface of the other mold Then hold the one mold and the front After disposing the parison between the embedded members and closing the mold to sandwich the parison, the concave portion is formed by projecting and deforming the projection and the portion serving as the back wall of the parison through the embedded member. At the same time as the front end of the parison is welded to the back surface of the portion that becomes the front wall of the parison, and then a pressurized fluid is introduced into the parison to expand along the outer surface of the cavity and the buried member, and at the same time, The inner ribs are formed by welding the opposing wall surfaces by pressing and deforming the gap between the member and the back wall forming cavity surface with the internal pressure of the pressurized fluid.
[0008]
[Action]
End of the buried embedded member in the inner ribs, because not protrude from the outer surface of the end wall, the deformation such as warping due to the difference in expansion and contraction due to the difference in thermal expansion coefficient between the base resin and the embedded member occurs do not do.
[0009]
Further, the end portion of the embedded member protruding to the outer surface of the end wall can be used as a functional member such as a locking portion or a fixing portion, and the physical strength is increased.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings.
[0011]
First, a first embodiment of a hollow double wall molded product according to the present invention will be described.
[0012]
FIG. 1 and FIG. 2 show a table top plate P using the hollow double wall molded product of this embodiment, and this table top plate P is a flat hollow double wall molded product 1 having a hollow double wall structure. The frame F is fitted to the periphery of the hollow double wall molded product 1.
[0013]
The hollow double-wall molded product 1 has a front wall 2 and a back wall 3 that are opposed to each other at an interval, and a peripheral portion of the both is closed by an end wall 4, and one end side is a back surface of the front wall 2. And the other end is integrally formed with the back wall 3 and is not visible from the outside. The inner rib 5 is embedded with a plate-like embedded member 6 extending in the longitudinal direction. And the latching | locking part 6a which is the both ends of the burying member 6 protrudes from the outer surface of the end wall 4, respectively. This latching | locking part 6a is for couple | bonding the frame F etc. which are mentioned later, and has the notch part 6b in the end wall side of the back wall side edge part.
[0014]
On the other hand, the frame F is a deformable material made of a flexible material such as rubber, and has a shape surrounding the end wall 4 of the hollow double wall molded article 1 over its entire peripheral surface. A fitting recess 7 into which the locking portion 6a is fitted is provided in a portion corresponding to the locking portion 6a protruding from the outer surface of the end wall 4 of the hollow double-wall molded product 1 described above on the inner peripheral surface thereof. It has been. For this reason, when fitting the frame F to the hollow double-wall molded product 1, the vicinity of the portion where the fitting recess 7 of the frame F is provided is pulled outward and partially enlarged and deformed. Thus, the table top plate P shown in FIG. 1 can be assembled by simply assembling the frame F to the hollow double wall molded product 1.
[0015]
Next, the first embodiment of the method for producing a hollow double-wall molded product of the present invention will be described by taking as an example the case of producing the hollow double-wall molded product shown in FIGS.
[0016]
First, a split mold used in this embodiment will be described.
[0017]
As shown in FIGS. 3 and 4, the divided mold has a front wall forming cavity surface 13 a that regulates the outer surface of the front wall 2 and surrounds the front wall forming cavity surface 13 a in the height direction of the end wall 4. One mold 11 having a cavity 13 having an end wall forming cavity surface 13b for regulating a part (about half in this embodiment) of the outer surface, and a back wall forming cavity surface for regulating the outer surface of the back wall 3 14a and the other mold 12 having the cavity 14 with the end wall forming cavity surface 14b surrounding the back wall forming cavity surface 14a and restricting the outer surface of the remaining portion of the end wall 4 in the height direction.
[0018]
Protrusions 18 project from portions corresponding to both ends in the longitudinal direction of the inner rib 5 on the mating surface of the other mold 12, and a portion excluding the projecting portion 18 and the cavity side of the projecting portion 18. A pinch-off portion 16 is formed by the peripheral edge portion, and a holding surface that opens from the distal end surface 18b to the distal end surface 18b in which the end portion of the embedded member 6 can be detachably inserted into the cavity-side surface of each protruding portion 18 is held. A groove 18a is provided. Here, the protruding amount of the protruding portion 18 from the pinch-off portion 16 other than the protruding portion 18 in the mold opening / closing direction is the tip of the embedded member 6 held by inserting both ends into the holding groove 18a when the mold closing is completed. Is set to a height at which a gap having a dimension described later is generated between the first mold 11 and the front wall forming cavity surface 13a.
[0019]
In a portion corresponding to the protrusion 18 on the mating surface of the end wall forming cavity surface 13b of one mold 11, there is a recess 17 having a shape in which the protrusion 18 is closely fitted when the mold is closed. are formed, the pinch-off portion 15 is formed by the cavity-side periphery portion and the recess 17 excluding the concave plant 17.
[0020]
Here, the depth of the holding groove 18a of the projecting portion 18 in the mold opening / closing direction is substantially the same as that of the front end surface 6c of the embedded member 6 and the front end surface 18b of the projecting member 18 when the engaging portion 6a of the embedded member 6 is inserted. The depth is set to be the same surface, and the size of the gap between the front end surface 6c of the embedded member 6 and the front wall forming cavity surface 13a of one mold 11 when the mold is closed is a recess 19a described later. It is desirable to set the size of the welded portion 19b so that its tip is in contact with the back surface of the portion that becomes the front wall of the Paris, that is, a size that is twice or less the thickness of the Paris.
[0021]
Next, the process of the manufacturing method of the hollow double wall molded product according to the present embodiment will be described.
[0022]
(1) As shown in FIGS. 3 and 4, one mold 11 and the other mold 12 are opened, and the embedded member 6 is inserted into the holding groove 18 a of the projecting portion 18 of the other mold 12 facing each other. By inserting and engaging the locking portions 6a, which are both ends of the two, they are detachably held at a predetermined interval. In this step, the embedded member 6 has a width (height) substantially the same as the depth of the holding groove 18 a, and the front end surface 6 c of the held embedded member 6 is substantially flush with the front end surface 18 b of the protrusion 18.
[0023]
(2) After the above (1), one mold 11 opened by extruding the Paris 19 made of a thermoplastic resin melted from an extrusion head of an extruder (not shown) and the two embedded members 6 are separated by a predetermined distance. After placing the other mold 12 held between the two, the mold closing is started. As the mold closing progresses, as shown in FIG. 5A, a part of the back wall of the Paris 19 is formed by the protrusion 18 of the other mold 12 and each of the embedded members 6 held. Projecting and deforming toward the surface wall, a groove-shaped recess 19a is formed following the shape of the embedded member 6 and the protrusion 18 that holds the embedded member. When the mold closing is completed, the tip of the recess 19a The welded portion 19b (see FIG. 5B) is formed by welding the portion to the back surface of the portion that becomes the front wall of Paris.
[0024]
(3) After the above (2), as shown in FIG. 5 (b), the cavities 13 and 14 and the embedment are buried by piercing a blow means such as a blow needle (not shown) into the Paris 19 and introducing a pressurized fluid. The opposing wall surface is expanded by pressing and deforming the gap between the embedded member 6 of the recess 19a and the back wall forming cavity surface 14a of the other mold 12 by the internal pressure of the pressurized fluid while expanding along the outer surface of the member 6. , The one end side is welded to the back surface of the front wall 2 and the other end side is integrally formed with the back wall 3, and the locking portion 6 a of the embedded member 6 protrudes from both end portions inside. The inner rib 5 in which the other portions are embedded is formed.
[0025]
(4) After said (3), it cools in a metal mold | die, then performs mold opening, takes out the hollow double-wall molded product 1, and removes an unnecessary burr | flash.
[0026]
In the embodiment described above, the hollow double-wall molded product having the two inner ribs 5 in which the embedded member 6 is embedded and the locking portions 6a that are both ends of the embedded member 6 project from the outer surface of the end wall, respectively. Although the case where it manufactures was shown, it is not restricted to this, either one end part of the embedded member 6 shall protrude from the end wall outer surface, or the number of the inner ribs in which the embedded member is embedded is one or three. This can be done. In addition, it is possible to mold a hollow double wall molded product in which either one end of the embedded member protrudes long from the outer surface of the end wall, and in this case, either one of the opposing projecting portions A holding groove penetrating from the inner surface of the cavity to the outer surface of the cavity is provided so that either one end of the embedded member protrudes outward from the mold, and the other end or the middle is held by an optional auxiliary holding member. Needless to say.
[0027]
In the present invention, as the thermoplastic resin, ABS resin, modified polyphenylene oxide resin, polycarbonate, polyamide, polypropylene, or the like is used.
[0028]
Furthermore, the use of the hollow double-wall molded product of the present invention is light weight, excellent mechanical strength and durability, and a cabinet shelf board, a table top board, a housing for an electric device, etc. that require good appearance, There are outer panels for automobiles.
[0029]
【The invention's effect】
Since the present invention is configured as described above, the following effects can be obtained.
[0030]
End of the buried embedded member to the inner rib, since the out exposed protruding from the end wall outer surface, can be utilized ends issued projecting as a functional member such as a locking portion and a fixing portion, embedded member No warpage due to the difference in expansion and contraction due to the difference in thermal expansion between the base resin and the base resin, excellent bond strength and durability, good appearance, and high mechanical strength such as rigidity Become.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view showing an example of a table top plate using a hollow double-wall molded product according to a first embodiment of the present invention, partially broken away.
FIG. 2 is a schematic partial perspective view showing only a main part, which is an exploded view of the table top plate shown in FIG. 1;
FIG. 3 is an explanatory view showing one step of the method for producing a hollow double-wall molded product of the first embodiment according to the present invention and showing a state in which the parison is arranged in a mold with a split mold.
4 is a schematic partial perspective view showing only a part of the divided mold shown in FIG. 3; FIG.
FIG. 5 shows the steps of the manufacturing method of the hollow double wall molded product of the first embodiment according to the present invention, (a) is a schematic partial sectional view of the main part of the mold showing a state in which the mold closing is in progress; FIG. 5B is a schematic partial cross-sectional view of the main part of the mold showing another process after the process shown in FIG.
6 is an explanatory diagram showing an example of a method for manufacturing a hollow plate of traditional.
[Explanation of symbols]
1 Hollow double wall molded product
2 front walls
3 back wall
4 end walls
5 inner ribs
6 Embedded member 6a Locking part 6b Notch
6c Tip surface 7 Fitting recess
11 One mold
12 other mold 13, 14 cavity 13a, 14a front wall forming cavity surface 13b, 14b end wall forming cavity surface 15, 16 pinch-off portion 17 recess
18 protrusions
19 Paris
19a recess

Claims (2)

The front wall and the back wall are opposed to each other at an interval, and the periphery of both is closed inside the hollow body, and one end side is welded to the back surface of the front wall and the other end side is the back wall. A hollow double wall molded product with an inner rib formed integrally with
A hollow double-wall molded product, wherein an embedded member extending in the longitudinal direction is embedded in the inner rib, and an end of the embedded member protrudes from an outer surface of the end wall.   2. The method for producing a hollow double-wall molded article according to claim 1, wherein the front wall forming cavity surface for regulating the outer surface of the front wall and the front wall forming cavity surface are enclosed in a height direction of the end wall. One mold having a cavity having a cavity surface for forming an end wall that regulates the outer surface of the part, a cavity surface for forming the back wall that regulates the outer surface of the back wall, and an end wall that surrounds the cavity surface for forming the back wall The other mold having a cavity with a cavity surface for forming an end wall that regulates the remaining portion in the height direction is opened, and the end of the embedded member is projected from the mating surface of the other mold. By inserting into a holding groove provided in the protruding portion, the protruding portion and the tip of the embedded member are held in a suspended state so that they are substantially flush with each other, and then between the one mold and the embedded member After placing Paris on And sandwiching the Paris, and forming a recess by projecting and deforming a portion that becomes the back wall of the Paris through the protruding portion and the embedded member, and the tip of the recess becomes the front wall of the Paris Welded to the back surface of the portion, and then introduced pressurized fluid into the Paris to expand along the outer surface of the cavity and the embedded member, and at the same time between the embedded member and the back wall forming cavity surface in the recess A method for producing a hollow double-wall molded article, wherein inner walls are formed by welding the opposing wall surfaces by pressing and deforming the voids with the internal pressure of the pressurized fluid.

Images