JP2001310379A - Method and apparatus for molding thermoplastic sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To hold a moldability of a deeply drawn part satisfactory and to enhance an appearance performance of a molding in a method and an apparatus for molding a thermoplastic sheet having a heavy weight to be used for molding a floor carpet or the like for a vehicle. SOLUTION: The apparatus for molding the thermoplastic sheet comprises a loose stretching mechanism such as a feeding thread mechanism 50 or the like at clamping frames 40 for supporting two or four sides of peripheral edges of a raw fabric sheet S. The method for molding the thermoplastic sheet comprises the steps of separating the clamping frames 40 from each other by the loose stretching mechanism in a heating step by a heater 60, approaching the frames 40 to each other by the loose stretching mechanism when press molded. Thus, a draw-down is prevented and a heating unevenness is suppressed. Further, a sliding amount of the sheet S into pressing molds 30 and 31 is assured. Thus, the good moldability is maintained at the deep drawn part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for forming a thermoplastic sheet suitable for forming floor carpets for vehicles and the like. The present invention relates to a method and an apparatus for forming a thermoplastic sheet.

[0002]

2. Description of the Related Art Normally, a floor carpet 1 for a vehicle laid on a floor surface of a vehicle extends along a toeboard portion 1a, a floor portion 1b, and a central front-rear direction depending on a portion to be laid, as shown in FIG. A tunnel portion 1c is provided. In particular, the toe board portion 1a and the tunnel portion 1c are set to have a deep drawing shape.

A floor carpet 1 for a vehicle is shown in FIG.
As shown in FIG. 1, a carpet material 3 having a PP (polypropylene) pile or the like planted thereon is laminated on a surface of a substrate 2 made of a PET (polyester) nonwoven fabric, and a backing material 4 such as a PE (polyethylene) resin is lined on the back surface. Have been.

A conventional molding apparatus and a molding method for molding a floor carpet 1 for a vehicle will be described. As shown in FIG. 12, a base material 2 is preliminarily laminated with a carpet material 3 and a backing material 4 on the front and back surfaces thereof. When two or four sides of the anti-sheet S are held by the clamp frame 5 and the press upper and lower dies 6 and 7 are in the mold open state, the heater device 8 is put into the mold to hold the original sheet S in a predetermined state. At this time, the clamp sheet 5 is stretched in the opposite direction by a cylinder or the like (not shown) to prevent the raw sheet S from hanging down due to the drawdown phenomenon and causing uneven heating. The tension is applied to S to prevent a heating variation in the heating process by the heater device 8.

[0005] Next, as shown in FIG. 13, after the heater device 8 is retracted out of the mold, the press upper mold 6 moves down, and the press lower mold 7 moves up, so that the press upper and lower molds 6 are moved.
By the mold clamping of 7, cold press molding into a required shape completes the molding of the floor carpet 1 for a vehicle.

[0006]

As described above, in the conventional molding apparatus and molding method for the floor carpet 1 for a vehicle, in the heating step of the raw sheet S, the raw sheet S is stretched in order to suppress a heating variation. Although the operation is performed, when the press upper and lower dies 6 and 7 are clamped, the raw sheet S is subjected to press forming while maintaining the stretched state, and therefore, in particular, the toe board portion 1a and the tunnel portion 1c of the floor carpet 1 for vehicles are used. As described above, in the deep drawing portion, it is pointed out that excessive tension is applied to the raw sheet S, and the molding defect such as the removal of the pile, the thinning of the product, or the shape defect in the carpet material 3 frequently occurs.

The present invention has been made in view of such circumstances, and a method and apparatus for forming a thermoplastic sheet for forming a molded article having a deep drawn portion, such as a floor carpet for a vehicle, includes a deep drawn portion. It is an object of the present invention to provide a method and an apparatus for forming a thermoplastic sheet capable of suppressing excessive tension from being applied to a raw sheet and performing good forming even in a deep drawing portion.

[0008]

In order to achieve the above object, the present invention provides a raw sheet obtained by cutting a thermoplastic sheet into a rectangular shape and holding two or four edges of the sheet by a clamp frame. Then, after the heat softening treatment, in a method of forming a thermoplastic sheet to be press-formed into a required shape, in the heat treatment step, the clamp frame is stretched outward to perform a heat treatment while suppressing a drawdown phenomenon, The raw sheet is fed into the press upper and lower molds, and the clamp frame is loosened according to the clamping of the press upper and lower molds, so that the raw sheet is slid into the press upper and lower molds and is suitable for the raw sheet at the time of press molding. It is characterized by giving a great tension.

Here, the method of the present invention comprises a heating step of the raw sheet and a press forming step. In the heating step of the raw sheet, a heater device is put into a press forming die to form the raw sheet. Heating may be performed, or the raw sheet whose peripheral edge is held by a clamp frame may be charged into a heating furnace or the like provided at a position different from the molding die to perform heating.

In the heating step and press forming step of the raw sheet, the loose stretch mechanism of the clamp frame applies tension to the raw sheet in the heating step to suppress the drawdown phenomenon. -The tension is alleviated by the stretch mechanism, the slip of the raw sheet into the mold is promoted, and the excessive tension can be prevented from being applied to the raw sheet.

[0011] The molding apparatus used in the method of the present invention comprises:
This is a thermoplastic sheet forming apparatus formed by press-forming a raw sheet made of a thermoplastic material into a required shape after heat-softening treatment, which is capable of mutually clamping and opening the mold and having a desired mold surface shape. The press forming upper and lower dies, the clamp frame supporting two or four sides of the peripheral edge of the raw sheet, and the opposing clamp frames are brought into contact with or separated from each other to apply tension to the raw sheet or to apply tension to the raw sheet. Loose to relax
And a stretching mechanism.

[0012] Here, loose loose used in the device of the present invention.
The stretch mechanism can use a spring or an air cylinder, but a rigid structure like a feed screw mechanism,
It is suitable for forming a bulky raw sheet applied to carpets and the like.

As is apparent from the above configuration, in the heating step of the raw sheet, the loose stretch mechanism provided on the clamp frame operates in a direction in which the clamp frame separates, so that tension is applied to the raw sheet. Granted,
The drawdown phenomenon due to heating is suppressed, and there is no heating variation in the raw sheet.

In the press forming step, the clamp frame operates in the direction in which the clamp frame approaches by the loose stretch mechanism provided on the clamp frame. Since the sheet is drawn following the mold surface, excessive tension is not applied to the raw sheet, and molding defects such as detachment of a pile, thinning, and shape defects can be prevented as much as possible.

If a feed screw mechanism is employed as the loose / stretch mechanism, a heavy original sheet can be reliably held, and it is suitable for molding large parts such as floor carpets for vehicles. By controlling the number of rotations of the motor, the forward / backward stroke amount of the clamp frame can be controlled with high accuracy, and it is possible to effectively cope with the molding of the product and the like.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a method and an apparatus for forming a thermoplastic sheet according to the present invention will be described in detail below with reference to the accompanying drawings. In the present embodiment, a method of forming a floor carpet for a vehicle and an example of application to a forming apparatus will be described.

FIGS. 1 and 2 are a perspective view and a sectional view showing a floor carpet for a vehicle manufactured by applying the present invention.
Is an overall view showing a first embodiment of a molding apparatus according to the present invention,
FIG. 4 is a plan view of the molding apparatus, FIGS. 5 to 7 show each step of the method of the present invention, FIG. 5 shows a setting step of the raw sheet, FIG. 6 shows a heating step of the raw sheet, and FIG. FIG. 8 is an explanatory view showing a press forming step of the raw sheet, FIG. 8 is a plan view showing a second embodiment of the forming apparatus according to the present invention, and FIG. 9 is an explanatory view showing a feed screw mechanism in the forming apparatus.

In FIG. 1 and FIG. 2, a floor carpet 10 for a vehicle is, as shown in FIG.
b, it is molded into a three-dimensional shape that matches the panel shape as in the tunnel portion 10c.
As shown in the figure, a carpet material 12 in which a PP (polypropylene) pile (area density 300 g / m ² ) is planted on the surface side of a substrate 11 made of a PET (polyester) nonwoven fabric (area density 120 g / m ² ), PE on the back side of substrate 11
A backing ground 13 (area density 800 g / m ² ) made of (polyethylene) resin is laminated. And
The floor carpet 10 for a vehicle is excellent in soundproofing, heat insulation and the like, and the floor carpet 10 for a vehicle is a large part, which is heavy and has a deep drawing portion set in the toeboard portion 10a and the tunnel portion 10c. I have.

By the way, in the present invention, in consideration of such a characteristic that the floor carpet 10 for a vehicle has a large weight and is provided with a deep drawing portion, there is no molding defect such as missing piles, scars and wrinkles. It is an object of the present invention to provide a method and an apparatus for forming a thermoplastic sheet that can obtain good formability in a floor carpet 10 for a vehicle.

That is, the molding apparatus used in the method of the present invention will be described with reference to FIGS. 3 and 4. The molding apparatus 20 comprises upper and lower dies 3 for cold press molding which can be closed and opened.
0, 31 and two opposite sides or four sides of a raw sheet of a thermoplastic resin material which is disposed on the outer periphery of the upper and lower molds 30, 31 for cold press molding and cut into a substantially rectangular shape. Clamp frame 40 (40a, 40b)
When the clamp frames 40a and 40b facing each other approach or separate from each other to apply tension to the raw sheet,
A loose-stretch mechanism (feed screw mechanism) 50 for relaxing tension and a heater for heating the raw sheet when the upper and lower dies 30 and 31 for cold press molding are opened before press molding. It is roughly constituted by the device 60.

More specifically, the upper and lower dies 30, 31 for cold press molding are respectively connected to an elevating cylinder (not shown) and can move up and down by a predetermined stroke. Toe board portion 10a or tunnel portion 1 of vehicle floor carpet 10
The concave and convex shape is set so that a deep drawn portion having a complicated shape such as 0c can be formed.

Further, the clamp frame 40 is provided on the molding apparatus 2.
At 0, two opposite sides of the raw sheet are illustrated and described in FIGS. 3 and 4, but the clamp frame 40 and the feed screw mechanism 50 as an example of the loose / stretch mechanism will be described below.

First, the upper and lower molds 30 for cold press molding,
A pair of feed screws 51 are provided on both sides of the base 31, and the feed screws 51 are rotationally driven by respective electric motors 52, and the electric motors 52 are attached to support members 53 via brackets 54.

Both ends of the feed screw 51 are rotatably supported by bearings 53a of a support member 53, and screw grooves 55a, 55a having screw directions opposite to each other are provided slightly inside the bearing 53a. The feed nut 5 is formed with a thread 55b and inserted into each of the thread grooves 55a, 55b.
Clamp frames 40a, 40b are attached to 6a, 56b.

Therefore, the opposed clamp frames 40a, 40
b, feed nuts 56a and 56b respectively attached to
The direction of the screw grooves 55a, 55b of the feed screw 51 is reversed, so that the opposing clamp frames 40a, 40b move in the direction approaching each other with respect to the rotation operation of the electric motor 52 in the forward and reverse directions. Alternatively, they will operate in the direction in which they are separated from each other.

Each of the clamp frames 40a, 40b is provided with a feed nut 56a, 56
The clamp claw 42 extends between the left and right feed screws 51 so as to be supported by the b. The clamp claw 42 is attached to the elongate base plate 41 so as to be openable and closable. Hold the peripheral part of.

The upper and lower dies 30, 3 for cold press molding are used.
When the mold 1 is in the mold open state, the heater device 60 (shown by a dotted line) is put into the mold, and the clamp frame 40 (40a, 40a) is inserted.
The raw sheet held in b) is heated to a predetermined temperature.

Next, a method of molding the floor carpet 10 for a vehicle using the molding apparatus 20 will be described with reference to FIGS.

First, as shown in FIG. 5, a raw sheet S made of a thermoplastic resin is set on the clamp frames 40a and 40b. The raw sheet S is made of a base material 11, a carpet ground 12, and a backing. The ground 13 is a bulky material obtained by cutting a three-layer raw sheet laminated in advance into a substantially rectangular shape. At the time of setting the material sheet S, the clamp frames 40a and 40b are located close to each other as shown by arrows in the drawing.

Next, when the setting of the raw sheet S is completed, the heater device 60 is put into the upper and lower dies 30, 31 for cold press molding, and the raw sheet S is heated and softened.

At this time, since the raw sheet S is large and considerably heavy, a drawdown phenomenon occurs due to its own weight. In order to prevent a heating variation due to the drawdown phenomenon, a feed screw mechanism is used. 50 is driven, and the opposing clamp frames 40a and 40b move in the direction away from each other as shown by the arrows in the drawing to apply tension to the raw sheet S, and the heat from the heater device 60 is evenly distributed. Is not transmitted to the raw material sheet S, and there is no heating variation.

After that, when the heating step is completed, the heater device 60 is retracted out of the mold, and then, as shown in FIG. 7, the elevating cylinder operates to lower the cold press molding upper mold 30, and The lower mold 31 for cold press molding rises, and the upper and lower molds 30 and 31 for cold press molding
The raw sheet S is pressed into a required shape.

At this time, the feed screw mechanism 50 is operated so that the electric motor 52 rotates in the direction opposite to the heating step so that the deep drawing portion can be formed favorably, so that the feed nuts 56a and 56b are moved. Clamp frame 40 facing through
a and 40b operate in the approaching direction as indicated by the arrows in the figure, and the raw sheet S is the upper and lower molds 3 for cold press molding.
It is drawn into the molds No. 0 and 31 and over-development, that is, tension is not excessively applied even in the deep drawing portion, and good molding is performed.

Since the amount of drawing into the press forming dies 30 and 31 can be accurately controlled by the number of rotations of the electric motor 52, good forming can be performed even when the heavy raw material sheet S is deep drawn. Done.

Accordingly, in the molded vehicle floor carpet 10, molding defects such as pile removal or thinning (scaling) of the carpet ground 12 occur even in a deep drawing portion such as the toeboard portion 10 a and the tunnel portion 10 c. Thus, the floor carpet 10 for a vehicle which is excellent in appearance performance without wrinkles can be formed.

FIGS. 5 to 7 show that the two opposite sides of the raw sheet S are held by clamp frames 40a and 40b, and the clamp frames 40a and 40b are fed to the feed screw mechanism 50.
The heat treatment and the cold press molding of the raw sheet S were performed by the loose stretching operation of the raw sheet S. The clamp frame 40 and the feed screw mechanism 50 were employed not only on the front and rear sides but also on the left and right sides. The molding may be performed by applying tension to the four sides around the substrate or relaxing the tension.

By the way, in this embodiment, the clamp frame 4
The feed screw mechanism 50 is employed as a loose / stretch mechanism attached to the zero, but a cylinder, a spring, or the like is used as a means for moving the clamp frame 40 forward and backward in order to impart or relax tension on the raw sheet S. You may.

FIGS. 8 and 9 show a second embodiment of the molding apparatus 20 according to the present invention.
In 0, the clamp frames 70 for holding the peripheral portion of the raw sheet S are provided along four sides of the rectangular raw sheet S, and the clamp frames 70 at each side are divided-type clamp frames 70a, 70b, 70c,..., And each of the split clamp frames 70a, 70b is independently operated by a corresponding loose / stretch mechanism such as a feed screw mechanism 80.

That is, the structure of the split clamp frame 70a and the feed screw mechanism 80 will be described. The feed screw 81 is rotatable in the forward and reverse directions by the electric motor 82, and the feed screw 81 is inserted into the feed screw 81. Nut 83
Are integrated with the split clamp frame 70a. And
A rail 84 and a support member 85 are mounted on both sides of the clamp frame 70a in a concave-convex fitting manner on both sides of the clamp frame 70a so that the clamp frame 70a does not rotate due to the rotation of the feed screw 81. , Is attached to a support member (not shown) integrally with the electric motor 82.

Accordingly, the clamp frame 70a moves forward and backward in the direction of coming and going with respect to the cold press forming dies 30 and 31 by rotating the electric motor 82 in the normal and reverse directions, and applies tension to the raw sheet S. Or by reducing the tension, the drawdown phenomenon in the heating step of the raw sheet S is suppressed, the heating variation is eliminated, and good moldability is ensured. By controlling the drawing amount of the raw sheet, good molding is performed.

In the molding apparatus 200 shown in FIGS. 8 and 9, each of the split clamp frames 70a, 70b, 70c
The loose stretch mechanism attached to the feed screw mechanism 8
In addition, a feed screw mechanism 80 is used in combination with a cylinder mechanism, etc.
It can be said that it is practically preferable to combine and use the other parts in consideration of the molding surface of the product, such as using an inexpensive cylinder mechanism or a spring.

[0042]

As described above, according to the method and apparatus for forming a thermoplastic sheet according to the present invention, a feed screw mechanism or the like is provided on a clamp frame which holds two or four sides of the peripheral edge of a raw sheet. In the heating step of the raw sheet, the clamp frame is operated in a direction to separate the clamp frame by the loose stretch mechanism,
In addition to suppressing the drawdown phenomenon of the raw sheet, at the time of press forming, the clamp frame is operated in the approaching direction by the loose stretch mechanism, and the amount of drawing of the raw sheet into the press die corresponding to the deep drawing part Therefore, it is possible to prevent as much as possible the formation of defects such as pile missing, skein, shape defect, wrinkle and the like in the carpet ground in the deep drawing portion, and it is possible to mass-produce molded products having excellent appearance quality performance.

Further, if a feed screw mechanism is employed as a loose stretch mechanism provided on the clamp frame, tension can be appropriately applied to a heavy raw sheet, or the tension can be appropriately reduced. By selecting the number of rotations in the forward and reverse directions, the forward / backward stroke amount of the clamp frame can be controlled with high accuracy, so that an effect can be obtained in which even a heavy raw sheet can be formed into a complicated curved shape.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a floor carpet for a vehicle formed by applying the method of the present invention.

FIG. 2 is a sectional view showing a configuration of the vehicle floor carpet shown in FIG.

FIG. 3 is an overall view showing a configuration of a first embodiment in a thermoplastic sheet forming apparatus according to the present invention.

4 is a plan view of the molding apparatus shown in FIG.

FIG. 5 is an explanatory view showing a setting step of a raw sheet in the method of the present invention.

FIG. 6 is an explanatory view showing a heating step of a raw sheet in the method of the present invention.

FIG. 7 is an explanatory view showing a step of press-forming a raw sheet in the method of the present invention.

FIG. 8 is a plan view showing a configuration of a second embodiment of the thermoplastic sheet forming apparatus according to the present invention.

FIG. 9 is an explanatory view showing a split clamp frame and a feed screw mechanism in the molding apparatus shown in FIG. 8;

FIG. 10 is a perspective view of a vehicle floor carpet.

FIG. 11 is a sectional view of a floor carpet for a vehicle.

FIG. 12 is an explanatory view showing a heating step in a molding step of a conventional floor carpet for a vehicle.

FIG. 13 is an explanatory view showing a press forming process of a conventional floor carpet for a vehicle.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Floor carpet for vehicles 10a Toe board part 10c Tunnel part 11 Base material 12 Carpet place 13 Backing place 20,200 Molding apparatus 30 Upper mold for cold press molding 31 Lower mold for cold press molding 40 (40a, 40b) Clamp frame 41 Plate base 42 Clamp claw 50 Feed screw mechanism 51 Feed screw 52 Electric motor 53 Support member 55 (55a, 55b) Screw groove 56 (56a, 56b) Feed nut 60 Heater device 70 (70a, 70b, 70c ...) Split clamp frame 80 Feed Screw mechanism 81 Feed screw 82 Electric motor 83 Feed nut 84 Guide rail 85 Support member S Raw sheet

Claims (5)

[Claims] 1. An edge of two or four sides of a raw sheet (S) obtained by cutting a thermoplastic sheet into a rectangular shape is held by a clamp frame (40), and after heating and softening, it is formed into a required shape. In the method of forming a thermoplastic sheet to be press-formed, in the heat treatment step, the clamp frame (40) is stretched outward to perform a heat treatment while suppressing a drawdown phenomenon, and then, the raw material is placed in a press upper and lower mold. The sheet (S) is supplied into the press upper and lower molds (30, 31) by loosening the clamp frame (40) in accordance with the clamping of the press upper and lower molds (30, 31). Wherein a suitable tension is applied to the raw sheet (S) during press molding. 2. The stretch and loosening operation of the clamp frame (40) is performed by a feed screw mechanism (50).
The method for forming a thermoplastic sheet according to claim 1, wherein the stroke amount of (0) is controlled. 3. A raw sheet (S) made of a thermoplastic material.
Is a thermoplastic sheet forming device formed by heat-softening and press-forming into a required shape. The upper and lower dies for press forming (30, 31) and two sides of the periphery of the raw sheet (S),
Alternatively, the clamp sheet (40) supporting the four sides and the opposing clamp frame (40) are brought into contact with and separated from each other, and the raw sheet (S)
And a loose stretching mechanism for imparting tension to or relaxing the tension. 4. A loose-stretch mechanism, wherein a feed nut (56a, 56b) is inserted into a screw groove (55a, 55b) having a different screw direction with respect to a feed screw (51) rotationally driven by an electric motor (52). Is a feed screw mechanism (50) which is fitted at a distance and which is configured by attaching the feed nut (56a, 56b) to the opposed clamp frame (40a, 40b). An apparatus for forming a thermoplastic sheet according to the above. 5. The clamp frame (40) is composed of a divided clamp frame (70) obtained by dividing one side of a raw sheet (S) into a plurality of blocks, and drives each of the divided clamp frames (70) independently. The thermoplastic sheet forming apparatus according to claim 3, further comprising a loose stretching mechanism (80) for causing the sheet to be loosened and stretched.