JPH11348110A - Manufacture of resin molded product having tank shape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve great cost reduction by heating each of a plurality of plugs, controlling the shift to a desired depth, and uniformly drawing each of the plurality of molding regions of a sheet stock into each cavity. SOLUTION: Both of heated draw-in plugs 3a, 3b are lowered to a desired depth in the oblique direction toward a sheet central portion 7, which allows a sheet stock 1 to be supplied by being drawn in each cavity 8a, 8b a predetermined quantity against the nip with small frictional resistance between a lower expander 5 and an upper expander 4. The draw-in plugs 3a, 3b are controlled to be lowered to a desired depth at the oblique angles α, β adapted to the three dimensions of each cavity 8a, 8b, and the vicinity of the sheet central portion 7 of the sheet stock 1 is not stretched, which permits the sheet material 1 to be supplied by uniformly drawing in both the sides of the sheet stock 1. Such a draw-in molding reduces the reduction of the plate thickness, thereby manufacturing a high-quality product having a multi-tank shape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a resin tank-shaped molded article for producing a plurality of thin resin molded articles such as an inner box of a refrigerator from a resin sheet material by thermoforming.

[0002]

2. Description of the Related Art Conventional plastic press molding machines are:
It consists of a lower mold, a plug, and a wrinkle-reducing part.By appropriately adjusting the clearance of the wrinkle-reducing part, the frictional force generated in the wrinkle-reducing part when the plug is lowered and molded is reduced, and at the same time,
It is possible to suppress the occurrence of wrinkles and draw in the material to perform molding. As a method of lowering the plug, there is known a method of moving in a vertical direction as shown in Japanese Patent Application Laid-Open No. 9-226001.

[0003]

However, in the above-described conventional method, when the lower die has a plurality of tanks, the material between the tanks receives tension from both, so that the material is not drawn in. Then, since the thickness reduction rate of this portion became large, molding could not be performed when the drawing tank was deep. For this reason, when forming the shape of a plurality of tanks, the partition plate is separately formed and inserted afterwards, and the manufacturing cost is accordingly increased.

[0004] An object of the present invention is to solve the above problems.
It is an object of the present invention to provide a method of manufacturing a resin tank-shaped molded article which enables a thin resin molded article having a plurality of tanks to be manufactured from a sheet material made of resin by thermoforming, thereby achieving a significant cost reduction.

[0005]

In order to achieve the above object, the present invention provides a loading step of heating a resin sheet material and loading it into a lower mold having a plurality of cavities; A peripheral portion and a partition portion of the sheet material heated and carried in on the mold are supported by a frame-shaped supporting member, and each of the plurality of plugs provided corresponding to the plurality of cavities is heated to control the movement to a desired depth. By drawing each of the plurality of molding regions of the sheet material into the respective cavities substantially uniformly, using the lower mold cavities for the respective molding regions of the resin sheet material. A method for producing a resin tank-shaped molded product, comprising: producing a resin thin-walled molded product in a plurality of tanks by curing the resin molded product by bringing it into close contact. Further, the present invention also provides a carrying-in step of heating a resin-made sheet material and carrying it on a lower mold having two cavities, and a peripheral portion of the sheet material heated and carried on the lower mold in the carrying-in step. The sheet material is supported by supporting the center partition with a frame-shaped support member, heating each of the two plugs provided corresponding to the two cavities, and lowering the plugs to a desired depth while approaching each other to the center partition. A step of pulling the molding regions on both sides of the central partition portion into the respective cavities by sliding the peripheral portion in the above, so that the molding regions of the resin-made sheet material are closely adhered using the cavities of the lower mold. A method for manufacturing a resin tank-shaped molded product, comprising manufacturing a resin thin-walled molded product in two tanks by curing the resin thinned product.

Further, the present invention is characterized in that two plugs are simultaneously lowered in the drawing step of the method for producing a resin tank-shaped molded product. Further, the present invention provides a carrying-in step of heating a resin-made sheet material and carrying it onto a lower mold having a plurality of cavities, and a peripheral portion of the sheet material heated and carried on the lower mold in the carrying-in step. The partition portion is supported by a frame-shaped support member, and among the plurality of plugs provided corresponding to the plurality of cavities, the first plug is heated and lowered to a desired depth to slide the peripheral portion of the sheet material. One of the first molding regions of the partition is drawn into the first cavity, and then the second plug is warmed and lowered to a desired depth while approaching the partition to remove a peripheral portion of the sheet material. Pulling in the other second molding area of the partition part into the second cavity by sliding, and bringing each molding area of the resin-made sheet material into close contact with each cavity of the lower mold. A method for producing a resin tank-shaped molded article, characterized by manufacturing a plurality tanks of the resin thin molded article is cured Te. Further, the present invention is characterized in that, in the drawing-in step of the method for producing a resin tank-shaped molded product, the frame-shaped support member has a function of suppressing wrinkles with respect to the sheet material. Further, the present invention, in the drawing step of the method for manufacturing a resin tank-shaped molded product, the frame-shaped support member, the occurrence of wrinkles on the sheet material is suppressed by varying the clearance between the corners and sides, and It is characterized by facilitating retraction.

Further, the present invention provides a carrying-in step of heating a resin-made sheet material and carrying it into a lower mold having a plurality of cavities, and a method of heating the sheet material carried into the lower mold in the carrying-in step. The peripheral part and the partition part are supported by a frame-shaped support member,
By warming each of the plurality of plugs provided corresponding to the plurality of cavities and controlling the movement thereof to a desired depth, each of the plurality of molding regions is formed in each cavity without significantly extending the vicinity of the partition portion in the sheet material. And a plug-in process in which each plug is raised to a desired position and then released, and compressed air is introduced into each cavity to form each sheet material drawn in in the pull-in process. A first expansion step in which a desired pressure is applied to the region to expand and expand (extend and form) the plug side, and a compressed air is introduced into each cavity to expand in the first expansion step. Each plug is lowered to a desired depth in each cavity while applying a desired pressure to each forming region of the sheet material thus extended. A second expansion step of extending a portion of the sheet material near the flange between each plug and the frame-shaped support member, and a vacuum operation in each of the cavities to perform the first and second expansion steps. Forming a plurality of resin thin-walled molded articles by bringing each molded area of the elongated sheet material into close contact with each cavity and releasing heat to obtain a resin thin molded article in a plurality of tanks. It is a manufacturing method.

Further, the present invention provides a carrying-in step of heating a resin sheet material and carrying it into a lower mold having two cavities, and a step of heating the sheet material carried into the lower mold in the carrying step. The peripheral portion and the central partition portion are supported by a frame-shaped support member, and each of the two plugs provided corresponding to the two cavities is heated and lowered to a desired depth while approaching each other to the central partition portion. The peripheral area of the sheet material is slid so that the molding regions on both sides of the central partition are drawn into the respective cavities without significantly extending the vicinity of the central partition, and then the two plugs are raised to a desired position. A retracting step of releasing and applying compressed air into each cavity to apply a desired pressure to the molding regions on both sides of the sheet material retracted in the retracting step. A first expansion step of expanding and extending (extending and forming) the plug material side, and introducing both sides of the sheet material expanded and expanded in the first expansion step by introducing compressed air into each cavity. A second pressure extending portion of each sheet material between the plugs and the frame-shaped support member near the flange by lowering the two plugs to a desired depth while applying a desired pressure to the molding region of And the molding areas on both sides of the sheet material extended in the first and second expansion steps are brought into close contact with the respective cavities by evacuating the respective cavities to cure the sheet material by releasing heat. And a forming step of obtaining two thin resin molded articles by using a resin tank.

Further, the present invention is characterized in that two plugs are simultaneously lowered in the drawing step of the method for producing a resin tank-shaped molded product. Further, the present invention provides a carrying-in step of heating a resin-made sheet material and carrying it onto a lower mold having a plurality of cavities, and a peripheral portion of the sheet material heated and carried on the lower mold in the carrying-in step. The partition portion is supported by a frame-shaped support member, and among the plurality of plugs provided corresponding to the plurality of cavities, the first plug is heated and lowered to a desired depth to slide the peripheral portion of the sheet material. One of the first molding regions of the partition is drawn into the first cavity, and then the second plug is warmed and lowered to a desired depth while approaching the partition to remove a peripheral portion of the sheet material. A sliding step of sliding the other second forming area of the partition into the second cavity, and then raising and releasing the first and second plugs to a desired position; A first expansion step in which compressed air is introduced into the space and a desired pressure is applied to each forming area of the sheet material drawn in the drawing step so as to expand the sheet material toward the plug side and expand (extend). In the state where compressed air is introduced into each cavity and a desired pressure is applied to each molding region of the sheet material expanded and expanded in the first expansion step, the respective plugs are desirably formed. A second expansion step of extending a portion of the sheet material in the vicinity of the flange between each plug and the frame-shaped support member by lowering to the depth of A molding step of bringing each molding area of the sheet material extended in the expansion step into close contact with each cavity and releasing heat to cure the resin material to obtain a resin thin molded article in a plurality of tanks. A method for producing a resin tank-shaped molded article.

Further, the present invention is characterized in that, in the drawing-in step of the method for producing a resin tank-shaped molded product, the frame-shaped support member has a function of suppressing wrinkles with respect to the sheet material. Further, the present invention, in the drawing step of the method for manufacturing a resin tank-shaped molded product, the frame-shaped support member, the occurrence of wrinkles on the sheet material is suppressed by varying the clearance between the corners and sides, and It is characterized by facilitating retraction. Further, the present invention is characterized in that the descent path and descent speed of each plug are appropriately controlled in the pull-in step of the method for manufacturing a resin tank-shaped molded product.

In particular, the present invention is characterized by a drawing step in a method for producing a resin tank-shaped molded product. That is, the sheet material is lowered from the plug corresponding to the central tank, and the sheet material is sequentially drawn and formed. The lowering of the plug is performed in the vertical direction when the central tank is drawn. Subsequently, the adjacent plug is lowered, and at this time, the plug is moved along an appropriate path at an appropriate speed while simultaneously controlling the moving mechanism having the axis in the horizontal direction and the moving mechanism having the axis in the vertical direction by the controller. By moving the sheet material, the sheet material is moved obliquely. By performing the drawing in the oblique direction in this manner, it is possible to draw the material from the opposite direction without significantly extending the material in contact with the partition with the central tank that cannot be drawn. After the material is drawn in the tank adjacent to the central tank, the drawing in the outer tank is similarly performed. At this time, the horizontal and vertical plug control mechanisms are simultaneously moved to lower the plug obliquely during molding.

Further, in order to minimize the elongation during sheet retraction molding and suppress the occurrence of wrinkles, the clearance at corners where wrinkle generation force is high is reduced, wrinkle generation is suppressed, and wrinkle generation stress is reduced. In the side portion where the amount of material to be drawn in is desired to be increased, the clearance is made larger and the drawing is performed. If a certain amount of thickness reduction is tolerated, the contradictory conditions of reducing the small thickness and reducing the area of the original plate by eliminating the wrinkle clearance after pulling in the required amount and then lowering the plug Molding can be performed in an optimal combination.

When the product has two tanks, the two tanks are simultaneously drawn in to reduce the molding cycle time. At this time, the material in contact with the central partition is tensioned by controlling the plug descending path so that the plugs corresponding to the respective tanks are sequentially lowered to the central partition, and the thickness of the material is reduced without decreasing the plate thickness. The material can be drawn in from outside and molded.

As described above, with the above-described structure, a thin resin molded article having a plurality of tanks, such as an inner box of a refrigerator, can be manufactured from a resin sheet material by thermoforming, so that the material cost and the operating cost are reduced. Can be greatly reduced to achieve a significant cost reduction.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for forming a plastic sheet material according to the present invention will be described with reference to the drawings. First, an embodiment of molding a box in a refrigerator will be described as a method for molding a plastic sheet material according to the present invention. FIG. 1 is a diagram showing the entire refrigerator 50 and the inner box 51. The inner box 51 is a container made of ABS resin or the like disposed inside the refrigerator 50 as shown in FIG. FIG. 1 shows a two-tank refrigerator having a refrigerator compartment 51b and a freezing compartment 51a, but there are also three-tank and four-tank refrigerators provided with a vegetable compartment, a chilled compartment and the like according to the purpose.

Next, a two-tank refrigerator inner box 5 according to the present invention.
A first embodiment of forming the molding No. 1 will be described with reference to FIGS. 2 to 7 are sectional views showing a method for thermoforming a resin sheet material according to a first embodiment of the present invention. FIG. 2 is a diagram showing a step of carrying in the heated sheet material. FIG. 3 is a view showing a drawing step of drawing two molding regions of the sheet material into each cavity by using two drawing plugs. FIG. 4 is a view showing a first expansion step of expanding and expanding two forming regions of the sheet material. FIG. 5 is a diagram showing a second expansion step of expanding and expanding the vicinity of the flange portions of the two forming regions of the sheet material. FIG. 6 is a diagram showing a molding process in which two molding regions of a sheet material are brought into close contact with each cavity, cooled and hardened to mold two resin molded products. FIG. 7 is a diagram illustrating a process of taking out two thermoformed resin molded products from the lower mold. 2 to 7, reference numeral 1 denotes a sheet material (resin sheet material) having a thickness of about 1 to 2 mm formed of an ABS resin or the like. 2a is a lower mold having cavities 8a and 8b, 3a and 3b are lead-in plugs, 4 is an upper wrinkle suppressing plate, 5 is a lower wrinkle suppressing plate, and 6 is a lower middle stopper plate. The pull-in plugs 3a, 3b, the upper and lower wrinkle suppressing plates 4, 5, and 6 are made of a light aluminum alloy, and hot water is circulated inside to warm the sheet material 1. Of course, when circulating the hot water, it may be configured to have a temperature control function. Reference numeral 7 denotes a central portion of the sheet material 1 which is in contact with the lower middle partition plate 6, and is hereinafter referred to as a central portion of the sheet. 8a and 8b are die cavities, 9 is a compressed air generator, 10 is a vacuum pump, and 11 is a switching valve.

First, as shown in FIG. 2, four sides of a sheet material 1 heated in advance by a material heating device (not shown) are clamped by an upper wrinkle suppressing plate 4 and a lower wrinkle suppressing plate 5, It is carried between the lower mold 2a and the pull-in plugs 3a, 3b. In order to carry the sheet material 1 between the lower mold 2a and the drawing plugs 3a and 3b, the upper wrinkle suppressing plate 4 is used.
It may be carried out by using another means different from the lower wrinkle suppressing plate 5.
Then, as shown in FIG. 2, the heating sheet material 1 carried and positioned between the lower mold 2a and the pull-in plugs 3a and 3b is sandwiched between the lower wrinkle restraint 5 and the upper wrinkle restraint 4 with a certain clearance. The clearance at this time is about 10% of the plate thickness in order to reduce the frictional resistance and minimize the occurrence of wrinkles. Next, from this state, as shown in FIG. 3, the draw-in plugs 3a and 3b are started to be lowered. At this time, the draw-in plugs 3a and 3b are both warmed obliquely so as to approach the lower die-closing plate 6. The retracted plugs 3a, 3b are lowered. If the pull-in plugs 3a, 3b were lowered straight, tension would be applied to the sheet central portion 7 from both sides, and as a result, the seat central portion 7 would extend without being drawn into either side. 3b, both sides of the sheet material 1 are pulled in obliquely toward the sheet central portion 7 to a desired depth, as shown by arrows in FIG. Without extending the vicinity of the central portion 7 of the sheet, it is possible to uniformly pull in the two tanks. That is, the heated plugs 3a, 3b
3 (a), as shown by an arrow in FIG. 3 (a), the sheet material 1 is lowered obliquely to a desired depth toward the sheet central portion 7 without extending the vicinity of the sheet central portion 7 of the sheet material 1. Both sides of the sheet material 1 can be uniformly drawn and supplied.

The reason why the inclination angle β for lowering the retracting plug 3b is larger than the inclination angle α for lowering the retracting plug 3a is that the retracting plug 3b
This is because the area of the box drawn in by the pull-in plug 3a is larger than the area of the box drawn in by the pull-in plug 3a. In the case of the cross-sectional direction shown in FIG. 3B, both the lead-in plugs 3a and 3b are lowered straight as indicated by arrows. As described above, by lowering the heated retraction plugs 3a and 3b obliquely toward the sheet central portion 7 to a desired depth as shown by arrows in FIG. 1 is supplied to each of the cavities 8a and 8b in a desired amount against the pinching of a small frictional resistance between the lower wrinkle restraint 5 and the upper wrinkle restraint 4.

Next, the periphery of the sheet material 1 is clamped by the lower wrinkle restraint 5 and the upper wrinkle restraint 4, and as shown in FIG. 4, compressed air is generated while simultaneously raising the retracting plugs 3a and 3b in the vertical direction. By sending the air generated by the device 9 into each of the mold cavities 8a and 8b, the entire box-shaped body of the heated sheet material 1 is expanded in the opposite direction to the cavities, and is uniformly extended. In addition, each mold cavity 8
a and 8b are configured to be sealed by the sheet material 1. Next, as shown in FIG. 5, each cavity 8a, 8b
With the internal pressure maintained, the pull-in plugs 3a, 3b are lowered vertically. As a result, the flange portion between the wrinkle suppressors 4, 5 in the sheet material 1 and each of the drawing plugs 3a, 3b is extended, and as a result, the sheet material 1
Thus, the entire portion corresponding to each of the cavities 8a and 8b is extended with little change in thickness.

Next, as shown in FIG.
Is switched to each cavity 8 by the evacuation device 10.
A vacuum is applied to the insides a and 8b, and the sheet material 1 extended corresponding to each of the cavities 8a and 8b is brought into close contact with the lower mold 2a, whereby a molded article 12 composed of two box-like bodies is formed. That is, at this time, since the lower mold 2a is in a cooled state,
The temperature of the sheet material 1 adhered to the lower mold 2a escapes due to heat transfer to the lower mold 2a, decreases and hardens, and the molded product 12 is completed. As described above, when the molded product 12 has sufficient strength, as shown in FIG. 7, the evacuation by the evacuation device 10 is released, and the vertical wrinkles 4 and 5 are raised vertically to suppress each wrinkle. The molded product 12 is taken out from the cavities 8a and 8b, and the molding is completed.

Next, an embodiment of a moving mechanism of the pull-in plug for moving the pull-in plugs 3a and 3b will be specifically described with reference to FIGS. FIG.
FIG. 2 is a front view showing a first embodiment of a retracting plug moving mechanism. The pull-in plugs 3a and 3b are made of a material obtained by winding a flannel cloth or felt on wood, or a light aluminum alloy in which hot water is circulated for heat retention. The moving mechanism of the plugs 3a, 3b is composed of a moving mechanism 19a in the vertical direction and a moving mechanism 19b in the horizontal direction because it is necessary to lower the pull-in plugs 3a, 3b in an oblique direction. A servo motor is used as a drive source in each of the moving mechanisms 19a and 19b to accurately control the positions and moving speeds of the pull-in plugs 3a and 3b. Further, the controller 20 controls each drive source of the moving mechanism 19a, 19b in the vertical direction and the horizontal direction so that each of the pull-in plugs 3a, 3b can be controlled to descend along a pre-programmed path. ing. Therefore, each of the pull-in plugs 3a and 3b is as shown in FIG.
As shown in (1), the lowering of the cavities 8a and 8b is controlled to a desired depth at the inclination angles α and β suitable for the three-dimensional shape. This makes it possible to uniformly draw in and supply both sides (portions corresponding to the cavities 8a and 8b) of the sheet material 1 without extending the vicinity of the sheet central portion 7 of the sheet material 1. However, each of the retraction plugs 3a and 3b is connected to each of the cavities 8a and 8b.
It is sufficient that the lowering is substantially controlled to a desired depth at the inclination angles α and β that conform to the three-dimensional shape, and it is not necessary to linearly move at the inclination angles α and β. That is, each of the pull-in plugs 3a, 3b is connected to the central portion of the sheet so that both sides of the sheet material 1 can be uniformly pulled in and supplied without extending the vicinity of the central portion 7 of the sheet material 1. It may be lowered while approaching to 7. In the first embodiment of the retracting plug moving mechanism, the vertical moving mechanism 19a is attached to the horizontal moving mechanism 19b.
The pull-in plugs 3a and 3b are configured to be individually movable in the vertical and horizontal directions. However, in the first embodiment in which the sheet material 1 is thermoformed, as shown in FIG. 3, two horizontal movement mechanisms 19b are attached to the movement output of one vertical movement mechanism 19a, and the two horizontal movement mechanisms 19b are attached. Even if each pull-in plug 3a, 3b is attached to each movement output of the direction moving mechanism 19b, each pull-in plug 3a,
The lowering control can be performed while the 3b is being moved to the center, and simplification can be achieved with one vertical movement mechanism 19a. On the other hand, it becomes impossible to individually control the movement of the pull-in plugs in the vertical direction.

FIG. 9 shows a second example of the retracting plug moving mechanism.
It is the front view which showed the Example of FIG. When the shape of the product to be manufactured is limited and versatility is not required, the plug moving mechanism may be configured as in the second embodiment. Here, reference numeral 21 denotes a plug moving mechanism using a servomotor or a hydraulic cylinder as a drive source, and the pull-in plugs 3a, 3b
Is configured to be movable in an oblique direction. The plug moving mechanism 21 is slidably supported by a guide 23 provided on a base 22. This prevents the cylinder piston from shifting in the lateral direction due to the reaction force from the material applied to the pull-in plugs 3a and 3b. The base 21 is fixed to a frame of the molding machine. Next, specific examples of the lower wrinkle suppressor 5 and the upper wrinkle suppressor 4 will be described with reference to FIGS.
As shown in FIG. 3, when lowering the retraction plugs 3 a and 3 b in an oblique direction to retract both sides of the sheet material 1,
The wrinkle generation force is large at the corners and small at the sides, and the amount of pull-in is greater at the sides. Therefore, as shown in FIG. 10, the upper wrinkle suppressor 4 is divided into a corner portion and a side portion, and is configured to be separately controllable. FIG. 10 shows the wrinkle holding mechanisms 4 and 5. 1 is a sheet material, 24 is an upper wrinkle suppressing base, 25 is a corner wrinkle suppressing, 26 is a side wrinkling suppressing, 27 is a wrinkling suppressing position control mechanism, and 28 is a hydraulic cylinder.

After the sheet material 1 is transported between the vertical wrinkles 4 and 5, the hydraulic cylinder 28 is driven and controlled so that the upper wrinkle-reducing base 29 is corner-wrinkled 25 and the side wrinkles 26 are reduced. Lower to just before touching 1.
Thereafter, the wrinkle restraint position adjusting mechanism 27 controls the corner wrinkle restraint 25 and the side wrinkle restraint 26 to an optimum position (clearance) between the wrinkle restraint 5 and the lower wrinkle restraint 5. In other words, by reducing the clearance due to the corner wrinkle restraint 25 between the lower wrinkle restraint 5, it is possible to suppress the wrinkle generated largely at the corner, and by increasing the clearance due to the side wrinkle restraint 26. Thus, it is possible to reduce the frictional force and draw in the sheet material 1 more. Although the corner wrinkle restraint 25 and the side wrinkle restraint 26 are each provided with the wrinkle restraint position adjusting mechanism 27, the side wrinkle restraint 26 alone has the wrinkle restraint position adjusting mechanism 27.
The clearance adjustment of the side wrinkle suppression 26 may be performed by the wrinkle suppression position adjustment mechanism 27, and the clearance adjustment of the corner wrinkle suppression 25 may be performed by controlling the hydraulic cylinder 28. As the wrinkle suppressing position adjusting mechanism 27,
For example, an air cylinder or the like may be used. FIG.
1 shows another wrinkle suppressing mechanism. In this case, the corner wrinkle holder 31 and the side wrinkle holder 32 have different thicknesses.
9 fixed. The base 29 is pressed by a hydraulic cylinder 28. Although the clearance between the corner and the side cannot be freely changed, the mechanism for suppressing wrinkles can be simplified when the versatility of the device is not required.

Next, a second embodiment of forming a refrigerator inner box having three or more tanks according to the present invention will be described with reference to FIGS. 12 to 14 are sectional views showing a method for thermoforming a resin sheet material according to a second embodiment of the present invention. FIG. 12 is a diagram showing a step of carrying in the heated sheet material. FIG. 13 is a view showing a drawing step of drawing the central molding region of the sheet material into the central cavity by using the central drawing plug. FIG.
It is a figure which shows the drawing process which draws the shaping | molding area | region of both sides of a sheet | seat material into two cavities on both sides using two drawing plugs on both sides. In the case where there are three or more drawing tanks, the method of the second embodiment is more preferable than the drawing method of the first embodiment. 1 is ABS
It is a sheet material (plastic material) formed of resin or the like and having a thickness of about 1 to 2 mm. 2b is a lower mold having cavities 13a, 13b, 13c, 14a, 14
b, 14c are retraction plugs, 16a, 16b, 17
Reference numerals a and 17b denote upper wrinkle suppressing plates, reference numeral 15 denotes a lower wrinkle suppressing plate, and reference numeral 18 denotes an inner partition plate. Lower die 2b, pull-in plugs 14a, 14b, 14c, upper and lower wrinkle suppressing plates 16
Reference numerals a, 16b, 17a, 17b, 15, and 18 are made of a light aluminum alloy, and circulate hot water therein to warm the sheet material 1. Of course, when circulating the hot water, it may be configured to have a temperature control function. 13a, 13
b and 13c are die cavities, 9 is a compressed air generator,
10 is a vacuum pump, 11 is a switching valve.

First, as shown in FIG. 12, the pre-heated sheet material 1 is carried into the forming apparatus as in the first embodiment, and the lower wrinkle suppressing plate 15 and the upper wrinkle suppressing 17a, 17b
, And between the inner partition plate 18 and the upper wrinkle suppressor 16a,
16b and the same clearance is secured. next,
From this state, as shown in FIG.
Is lowered vertically. At this time, the adjacent plugs 14b, 1
4c is not yet lowered. Therefore, the sheet material 1 is
Inner partition plate 1 located on the lower surface of plugs 14b, 14c
8 and slides over the lower wrinkle restraining plate 15 and is drawn into the central die cavity 13a. Then, this plug 14a
Is completed, the adjacent plugs 14b, 14b
Start to pull in both sides of the sheet material 1 at c. At this time, the plugs 14b and 14c do not descend vertically as shown by arrows in FIG.

As described above, by sequentially drawing the sheet material 1 into the cavities 13a, 13b and 13c, the sheet material in contact with the inner gap 18 is prevented from being elongated, and the sheet material is prevented from being stretched. 1 can be pulled in and supplied.

Thereafter, the sheet material 1 is clamped by the lower wrinkle restraint 15 and the upper wrinkle restraints 17a and 17b, and is formed in the same manner as in the first embodiment, and is formed of three or more box-like bodies. A molded article will be molded.

The moving mechanism of the plugs 14a, 14b, 14c can be configured as shown in FIGS. 8 and 9. Also, upper wrinkle suppressors 16a, 16
b, 17a, and 17b can be specifically configured as shown in FIGS.

A second method for thermoforming a box-shaped body of three or more tanks.
The method of the first embodiment can be applied to the method of the first embodiment for thermoforming a two-tank box. That is, first,
If the retracting plug 3a is lowered straight down similarly to the retracting plug 14a, and then the retracting plug 3b is lowered while approaching the center similarly to the retracting plug 14c,
As shown in FIG. 14, the sheet material 1 can be drawn into the cavities 8a and 8b and supplied without extending the sheet material in the vicinity of the lower middle partition plate 7 in the vicinity. However, since it is necessary to lower the pull-in plugs 3a and 3b separately, it takes more time and efficiency than in the first embodiment in which the pull-in plugs 3a and 3b are lowered while simultaneously moving to the center. Become.

In the above-described embodiment, the inner box of the refrigerator has been described as an example. However, a product having a plurality of box-shaped bodies such as a plastic sheet material (resin sheet material) can be manufactured by thermoforming. Clearly it can be applied to things.

[0031]

According to the present invention, it is possible to produce a high-quality double-tank-shaped product by reducing the thickness reduction by the draw-in process. Compared to the case of producing a product with a shape of and inserting a partition plate created by injection molding into the product later to manufacture a product with a double tank shape, material cost and labor cost can be greatly reduced To play.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an appearance of a refrigerator according to the present invention and an inner box thereof.

FIG. 2 shows a first example of forming a two-box refrigerator box according to the present invention.
FIG. 3 is a front cross-sectional view illustrating a first step (a carrying-in step) of the sheet material thermoforming method according to the example.

FIG. 3 (a) is a second embodiment of the sheet material thermoforming method according to the first embodiment of the present invention for forming the two refrigerator inner boxes according to the present invention.
(B) is a side sectional view of (a).

FIG. 4 shows a first example of forming a two-box refrigerator box according to the present invention.
It is a front sectional view showing the 3rd process (1st expansion process) of the thermoforming method of the sheet material which is an example of Example.

FIG. 5 shows a first example of forming a two-box refrigerator box according to the present invention.
It is a front sectional view showing the 4th process (2nd expansion process) of the thermoforming method of the sheet material which is an example of Example.

FIG. 6 shows a first example of molding a two-box refrigerator box according to the present invention.
It is a front sectional view showing the 5th process (formation process) of the thermoforming method of the sheet material which is an Example of.

FIG. 7 shows a first embodiment of forming a two-box refrigerator box according to the present invention.
It is a front sectional view showing the 6th process of the sheet material thermoforming method which is an example of Example.

FIG. 8 is a view showing a first embodiment of a plug moving mechanism according to the present invention.

FIG. 9 is a view showing a second embodiment of the plug moving mechanism according to the present invention.

FIG. 10 is a view showing a first embodiment of a wrinkle suppressing mechanism according to the present invention.

FIG. 11 is a view showing a first embodiment of a wrinkle suppressing mechanism according to the present invention.

FIG. 12 is a front sectional view showing a first step (loading step) of a sheet material thermoforming method according to a second embodiment of the present invention for forming a three-box refrigerator box according to the present invention.

FIG. 13 is a front cross-sectional view showing a second step (retraction step) of the sheet material thermoforming method according to the second embodiment of the present invention for forming a three-box refrigerator box according to the present invention.

FIG. 14 is a front sectional view showing a third step (retraction step) of the sheet material thermoforming method according to the second embodiment of the present invention for forming a three-box refrigerator inner box according to the present invention.

[Explanation of symbols]

1 ... sheet material, 2a, 2b ... lower mold, 3a, 3b,
14a, 14b, 14c ... withdrawal plug, 4, 16
a, 16b, 17a, 17b ... upper wrinkle suppressing plate, 5, 15
... lower wrinkle suppressing plate, 6 ... lower middle stiffener plate, 7 ... sheet central part, 8a, 8b, 13a, 13b, 13c ... mold cavity, 9 ... compressed air generator, 10 ... vacuum pump,
Reference numeral 11: switching valve, 12: molded product, 19a: vertical moving mechanism, 19b: horizontal moving mechanism, 20:
Control device, 25 ... corner wrinkle control, 26 ... side wrinkle control.

Claims (12)

[Claims] 1. A carrying-in step of heating a resin-made sheet material and carrying it into a lower mold having a plurality of cavities, and a peripheral portion and a partition of the sheet material carried into the lower mold by being heated in the carrying-in step. The portion is supported by a frame-shaped support member, and a plurality of plugs provided corresponding to the plurality of cavities are warmed and controlled to move to a desired depth, whereby each of the plurality of molding regions of the sheet material is formed in each cavity. And forming a resin thin-walled molded article in a plurality of tanks by curing each molding area of the resin-made sheet material using each cavity of the lower mold. A method for producing a resin tank-shaped molded product. 2. A carrying-in step of heating a resin-made sheet material and carrying it into a lower mold having two cavities; and a peripheral portion and a center of the sheet material heated and carried into the lower mold in the carrying-in step. Is supported by a frame-shaped supporting member, and each of the two plugs provided corresponding to the two cavities is heated and lowered to a desired depth while being brought close to each other to the central partition, thereby reducing the sheet material. Pulling the molding areas on both sides of the central partition into the respective cavities by sliding the peripheral part, and curing the molding areas of the resin sheet material using the cavities of the lower mold. Producing a resin thin-walled molded product in two tanks. 3. The method according to claim 2, wherein two plugs are simultaneously lowered in the drawing step. 4. A carrying-in step of heating a resin-made sheet material and carrying it into a lower mold having a plurality of cavities, and a peripheral portion and a partition of the sheet material carried and heated on the lower mold in the carrying-in step. The portion is supported by a frame-shaped support member, and among a plurality of plugs provided corresponding to the plurality of cavities,
Warming the first plug, lowering it to a desired depth, and sliding the peripheral portion of the sheet material to draw one of the first forming regions of the partition into the first cavity;
Next, the second plug is warmed and lowered to a desired depth while being brought close to the partition portion, and the peripheral portion of the sheet material is slid so that the other second forming area of the partition portion is in the second shape.
A resin drawing process, wherein each molding region of the resin sheet material is cured by using each cavity of the lower mold to produce a resin thin molded product having a plurality of tanks. A method for producing a tank-shaped molded product. 5. The method according to claim 1, wherein in the drawing step, the frame-shaped supporting member has a function of suppressing wrinkling of the sheet material. 6. In the drawing-in step, the frame-shaped support member has different clearances at the corners and the sides to suppress the generation of wrinkles on the sheet material and facilitate the drawing-in. A method for producing the resin tank-shaped molded product according to claim 1. 7. A carrying-in step of heating a resin-made sheet material and carrying it into a lower mold having a plurality of cavities, and a peripheral portion and a partition of the sheet material heated and carried into the lower mold in the carrying-in step. The portion is supported by a frame-shaped support member, and a plurality of plugs provided corresponding to the plurality of cavities are warmed and controlled to move to a desired depth, whereby each of the plurality of molding regions of the sheet material is formed in each cavity. And a plug-in process in which each plug is raised substantially to a desired position and then released, and compressed air is introduced into each cavity so that each of the sheet materials pulled in in the pull-in process is retracted. A first inflation step of applying a desired pressure to the molding region to inflate and expand the plug side, and introducing compressed air into each cavity to inflate in the first inflation step. The respective plugs and the frame-shaped supporting member are lowered by lowering each plug to a desired depth in each cavity in a state in which a desired pressure is applied to each molding region of the sheet material thus extended. A second expansion step of extending a portion of the sheet material in the vicinity of the flange, and evacuation of each cavity to form each molding region of the sheet material extended in the first and second expansion steps in each cavity. And forming a resin thin-walled molded article in a plurality of tanks by releasing the heat by adhering to the resin to form a resin tank-shaped molded article. 8. A carrying-in step of heating a resin-made sheet material and carrying it into a lower mold having two cavities, and a peripheral portion and a center of the sheet material heated and carried into the lower mold in the carrying-in step. Is supported by a frame-shaped supporting member, and each of the two plugs provided corresponding to the two cavities is heated and lowered to a desired depth while being brought close to each other to the central partition, thereby reducing the sheet material. A sliding step of sliding the peripheral portion to draw the molding regions on both sides of the central partition into the respective cavities, and then raising the two plugs to a desired position and releasing the plugs, and forcing compressed air into the respective cavities. A first expansion step of applying a desired pressure to the molding regions on both sides of the sheet material introduced and drawn in in the drawing step and expanding the sheet material to the plug side to extend the sheet material; The compressed air is introduced into the cavity of the sheet material, and the two plugs are brought into a desired state while applying a desired pressure to the molding regions on both sides of the sheet material expanded and expanded in the first expansion step. A second expansion step of extending a portion of the sheet material near the flange between each plug and the frame-shaped support member by lowering the cavity to a depth; A molding step in which molding areas on both sides of the sheet material extended in the expansion step are brought into close contact with the respective cavities and cured by releasing heat to obtain two resin thin molded articles. Method for manufacturing a shaped article. 9. The method according to claim 8, wherein two plugs are simultaneously lowered in the drawing step. 10. A carrying-in step of heating a resin-made sheet material and carrying it into a lower mold having a plurality of cavities, and a peripheral portion and a partition of the sheet material heated and carried into the lower mold in the carrying-in step. The portion is supported by a frame-shaped support member, and among a plurality of plugs provided corresponding to the plurality of cavities,
Warming the first plug, lowering it to a desired depth, and sliding the peripheral portion of the sheet material to draw one of the first forming regions of the partition into the first cavity;
Next, the second plug is warmed and lowered to a desired depth while being brought close to the partition portion, and the peripheral portion of the sheet material is slid so that the other second forming area of the partition portion is in the second shape.
A retracting step in which the first and second plugs are lifted to a desired position and then released, and compressed air is introduced into each cavity to remove the sheet material retracted in the retracting step. A first expansion step of applying a desired pressure to each molding area to expand and expand the plug side; and introducing compressed air into each cavity to expand and expand the first expansion step in the first expansion step. In a state where a desired pressure is applied to each forming region of the flattened sheet material, by lowering each plug to a desired depth, the vicinity of the flange of the sheet material between each plug and the frame-shaped support member is reduced. A second expanding step of extending a portion, and forming each cavity of the sheet material expanded in the first and second expanding steps by evacuating the respective cavities to each of the cavities. Method for producing a resin tank-shaped molded article characterized by having a molding step of obtaining a plurality tanks of the resin thin molded article is cured by heat to escape by close contact with the I. 11. The method according to claim 7, wherein in the drawing-in step, the frame-shaped supporting member has a function of suppressing wrinkling of the sheet material. 12. In the drawing-in step, the frame-shaped support member has different clearances at the corners and the sides to suppress the generation of wrinkles on the sheet material and facilitate the drawing-in. Claim 7 or 8 or 10
A method for producing the resin tank-shaped molded article according to the above.