JPH07117108A - Mold for deep drawing blow molding - Google Patents

Abstract

PURPOSE:To obtain a blow molding having a relatively long deep-drawn portion without causing any defect. CONSTITUTION:A mold has a front mold 1 having a first deep drawing face 1a extending in the deep drawing direction and a push core 2 swinging in a direction which intersects with the deep drawing direction and having a second deep drawing face 2a opposed to the first deep drawing face 1a at a swinging end. The front mold 1 and the push core 2 maintain contact with each other at their contact portions after the swing of the push core 2. Fluid outlet ports 1c, 3b are formed at the contact portions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deep drawing blow molding die.

[0002]

2. Description of the Related Art Conventionally, as described in "Double Wall Forming Process in Blow Molding (1992 Issued, Molding Volume 4, No. 3)", a first deep drawing surface extending in a deep drawing direction. Having a concave first mold having a concave shape and a convex second mold having a second deep drawing surface that is relatively linearly moved in parallel with the deep drawing direction and that faces the first deep drawing surface at the linear movement end. A mold for deep drawing blow molding is known.

[0003]

For example, when forming a meter hood of an instrument panel in which a deep drawing portion is hollow and used for an air duct, as shown in FIGS. 8 and 9.
The direct-acting mold shown in is used. With this mold,
As shown in, the first deep drawing surface 91 extending in the deep drawing direction
A front die (first die) 91 having a is fixed to the die base 90, and the fixed die 93 and the front die 9 fixed to the die base 90.
A convex push core (second type) 92 is housed between the two. A hydraulic cylinder 94 is provided between the push core 92 and the die base 90, and the push core 92 linearly moves in parallel with the deep drawing direction by the hydraulic cylinder 94, and has its second deep drawing surface at the direct acting end. 92a can be opposed to the first deep drawing surface 91a. As shown in FIG. 9, a back mold 95 is linearly movable at a position facing the push core 92, and another push core 96 is linearly movable by a hydraulic cylinder 97 on the front mold 91. Has been.

In this mold, as shown in FIG.
A molten resin P such as a parison is interposed between 1 and the push core 92, and the molten resin P is blown as shown by an arrow B. Then, as shown in FIG. 9, by extending the hydraulic cylinder 94, the push core 92 is linearly moved as shown by an arrow A to move the first core.
The deep drawing surface 91a and the second deep drawing surface 92a are opposed to each other.
At the same time, the back mold 95 is directly moved as shown by the arrow C, and the meter portion is pressure-bonded to form the hollow deep-drawn portion. At this time, the other pressing core 96 is directly moved by the hydraulic cylinder 97 to form a mounting hole.

However, in the above-mentioned direct-acting die, when the length of the deep drawing portion is large, the tip of the deep drawing portion may be broken. That is, in blow molding, the limit of the molten resin extruded from the die head is usually 3 to 4 times as long. This limit is reflected in the blow ratio H / D, where D is the width of the deep drawn portion and H is the length of the deep drawn portion, and the length H of the deep drawn portion is the allowable blow ratio H.
When it exceeds / D, it is considered that a tear occurs. Thus, it is difficult to mold a blow-molded product having a relatively long deep-drawn portion with a direct-acting mold.

[0006] Further, the above-mentioned publications and JP-A-2-1503.
As described in Japanese Patent Publication No. 32, No. 32, a convex first mold having a first deep drawing surface extending in the deep drawing direction, and swinging from the outer side to the inner side in a direction intersecting the deep drawing direction and shaking. First at the end
An oscillating type deep drawing blow molding die having a deep drawing surface and a second die having a second deep drawing surface facing the deep drawing surface is also known.

According to this oscillating die, even if the deep drawing portion has a large length, the second drawing oscillates from the outer side to the inner side in the direction intersecting with the deep drawing direction. The blow ratio H / D is reduced because the width D of the blow is increased. Therefore, the elongation of the molten resin is relaxed, and it becomes possible to form a blow-molded product having a relatively long deep-drawn portion.

However, in such an oscillating mold,
When the second die oscillates from the outer side to the inner side in the direction intersecting the deep drawing direction, whereby the first deep drawing surface and the second deep drawing surface do not face each other, the first die is oscillated after the second die is oscillated. A contact part where the contact between the mold and the second mold is maintained is generated, and the molten resin easily bites into the contact part. Therefore, the blow-molded product may be defective.

The present invention has been made in view of the above-mentioned conventional problems, and a deep-drawing blow-molding metal capable of forming a blow-molded product having a relatively long deep-drawing portion without causing defects. Intended to provide a type.

[0010]

A deep drawing blow molding die of the present invention is provided with a first die having a first deep drawing surface extending in the deep drawing direction and a first die having a first deep drawing surface. A second die having a second deep drawing surface that oscillates and faces the first deep drawing surface at an oscillating end, and the first die and the second die after the second die is oscillated. Is a deep-drawing blow molding die that produces a contact portion where the contact is maintained, wherein a fluid outlet is formed at the contact portion.

[0011]

When a blow-molded product having a relatively long deep-drawing portion is formed by the deep-draw blow-molding die of the present invention,
A molten resin is interposed between the first mold and the second mold to blow the molten resin. Then, the second die is relatively swung in a direction intersecting the deep drawing direction. At this time, even if the deep drawing portion has a large length, the width of the deep drawing portion is increased due to the relative swinging of the second die in the direction intersecting the deep drawing direction, so that the blow ratio is reduced. ing. Therefore, the elongation of the molten resin is relaxed, and the molten resin forming the deep drawn portion is prevented from breaking at this stage.

Thereafter, the first deep drawing surface and the second deep drawing surface are opposed to each other, and a contact portion where the first die and the second die are kept in contact with each other after the second die is swung is formed. The resin is removed from the contact portion by the fluid blown out from the fluid outlet, and the molten resin is prevented from being caught in the contact portion.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIGS. 1 to 5, this deep-drawing blow molding die is for forming a meter hood of an instrument panel that is used in an air duct with a deep-drawing portion being hollow.

That is, in this die, as shown in FIG. 1, a front die (first die) 1 having a first deep-drawing surface 1a extending in the deep-drawing direction is fixed to the die base 10 and is attached to the die base 10. A convex push core (second mold) 2 is housed between the fixed mold 3 and the front mold 1 which are fixed. A direct-acting hydraulic cylinder 4 is provided between the push core 2 and the die base 10, the push core 2 is slidably provided on the slide base 5, and a swing motion is provided between the slide base 5 and the fixed die 3. A hydraulic cylinder 6 is provided. The push core 2 swings around the rotation center O in a direction intersecting the deep drawing direction by the extension of the swing hydraulic cylinder 6 when the linear motion hydraulic cylinder 4 is shortened, and By extending the direct-acting hydraulic cylinder 4 during extension, the direct-acting hydraulic cylinder 4 is moved in parallel with the deep drawing direction, and the second deep-drawing surface 2a can be opposed to the first deep-drawing surface 1a at the swing end and the direct-acting end. ing.

In the front mold 1, a suction port 1b is opened at the tip of the first deep drawing surface 1a, and this suction port 1b is connected to a vacuum pump (not shown). A breathable mold material (“Porcerax” manufactured by Shinto Kogyo Co., Ltd.) is provided on the first deep-drawing surface 1a side of the suction port 1b, and the breathable mold material is also a part of the first deep-drawing surface 1a. Are configured. Further, a first fluid outlet 1c is opened on the lower end surface of the front mold 1 on the die base 10 side from the suction inlet 1b,
The first fluid outlet 1c is connected to a compressor (not shown).

The stationary die 3 is formed with an arcuate surface 3a around the center of rotation O for guiding the tip of the slide base 5. A second fluid outlet 3b is opened on the upper end surface of the fixed mold 3 on the side opposite to the die base 10 with respect to the arc surface 3a, and the second fluid outlet 3b is also connected to a compressor (not shown). As shown in FIGS. 2 to 4, a back mold 7 is provided so as to be linearly movable at a position facing the linear motion direction of the push core 2, and the front mold 1 is provided with another push core 8 which is a hydraulic cylinder 9.
It is provided so that it can be moved directly.

In this mold, the meter hood is molded according to the time chart shown in FIG. That is, as shown in FIG. 1, the parison P, which has been completely ejected from the die head, is interposed between the front mold 1 and the pressing core 2, pre-pinched, and then blown at a blow pressure P _x of ² kg / cm ² with an arrow B. Is pre-broken. Thereafter, the back mold 7 is directly moved (see FIG. 2, arrow E) to start the mold closing operation, and the swinging hydraulic cylinder 6 is extended from the mold closing slow position to move the slide base 5 as shown by the arrow A. At the same time, the push core 2 is swung along the arc surface 3a.

At this time, even if the length H of the deep drawing portion is large, the width D of the deep drawing portion is increased by swinging the push core 2 in the direction intersecting the deep drawing direction, so that the blow is performed. The ratio H / D is reduced to about 1/3.
Therefore, the elongation of the parison P is relaxed and the parison P forming the deep-drawn portion is prevented from breaking. at the same time,
Low-pressure air is blown from the compressor via the first and second fluid outlets 1c and 3b as indicated by arrows X and Y. Therefore, at this time, the first deep drawing surface 1a and the second deep drawing surface 2a
The front end portion of the front mold 1 is facing each other, and the front mold 1 and the pressing core 2 tend to make contact with each other in the vicinity of the first fluid outlet 1c, and the arc surface 3a near the second fluid outlet 3b.
However, the parison P is removed from the contact parts by the low pressure air blown from the first and second fluid outlets 1c and 3b, and the parison P is removed.
Are prevented from biting into their contact area.

After passing the mold closing slow position, the back mold 7 gradually moves linearly as shown by arrow E to the mold closing position as shown in FIG. At this time, blow is performed as indicated by an arrow B with a blow pressure P _x of 4 kg / cm ² . Thereby, a hollow is formed. At the same time, the arrow Z from the vacuum pump through the suction port 1b
Vacuuming is started as shown in. As a result, the parison P is easily moved in the deep drawing direction, and
The low pressure air blown from the fluid outlets 1c and 3b is discharged. In this way, the parison P reaches the vicinity of the tip of the first deep drawing surface 1a.

When the push core 2 reaches the swing end, the first deep drawing surface 1a and the tip of the second deep drawing surface 2a are opposed to each other, and the front mold 1 and the push core 2 are connected to the second fluid outlet. Although the contact surfaces are formed on the circular arc surface 3a near 3b, the parison P
Is removed from the contact portion by the low-pressure air blown from the second fluid outlet 3b, and the parison P is prevented from being caught in the contact portion. At this time, the first fluid outlet 1c is closed by the upper end surface of the push core 2, and the supply of low pressure air from the first fluid outlet 1c is stopped.

Then, as shown in FIG. 3, by extending the direct-acting hydraulic cylinder 4, the push core 2 is moved linearly along the slide base 5 as shown by an arrow C. When the push core 2 reaches the direct acting end, the first deep drawing surface 1a and the second deep drawing surface 2a
And are completely opposite. As a result, the meter portion is crimped to form the hollow deep-drawn portion. At this time, the second fluid outlet 3b is closed by the lower end surface of the push core 2, and the supply of low-pressure air from the second fluid outlet 3b is stopped.

After that, blow is performed as indicated by an arrow B with a blow pressure P _x of 6 kg / cm ² . As a result, the parison P reaches the tip of the first deep drawing surface 1a. At this time, the breathable mold material prevents the parison P from entering the suction port 1b. At the same time, as shown in FIG. 4, the hydraulic cylinder 9 is extended to linearly move the other push cores 8 as indicated by arrows J and I (see FIG. 5) to form mounting holes.

After that, the vacuum pressure from the suction port 1b is stopped, and at the same time, the blow pressure P _x is gradually reduced to exhaust the air. Then, as shown in FIG.
By shortening, the pushing core 2 is moved linearly along the slide base 5 as indicated by arrow G. When the push core 2 reaches the starting end, the second fluid outlet 3b is released from the lower end surface of the push core 2, so that the second fluid outlet 3b is released from the compressor.
The low-pressure air is blown out via the arrow mark Y. As a result, the vicinity of the second fluid outlet 3b of the meter hood where the parison P is cooled is easily released.

Next, the swinging hydraulic cylinder 6 is shortened to swing the push core 2 along with the slide base 5 along the arcuate surface 3a as indicated by an arrow H. When the push core 2 separates from the swinging end, the first fluid outlet 1c is opened from the upper end surface of the push core 2, so that the low pressure air from the compressor passes through the first fluid outlet 1c as indicated by arrow X. Is blown out. As a result, the vicinity of the first fluid outlet 1c of the meter hood can be easily released. When the push core 2 reaches the starting end, the blow pressure P _x is set to 0 kg / cm ² , and then the back mold 7 is directly moved (see FIG. 4, arrow F) to return to the mold open position.

Thus, in this mold, the blow ratio H / D
Is reduced to about 1/3, the parison P forming the deep-drawn portion can be prevented from being torn, and the degree of uneven thickness can be reduced to about 1/3, without causing defects. It is possible to form a meter hood having an extremely long deep drawn portion. Further, in this mold, since the degree of uneven thickness is reduced, it is possible to reduce the absolute thickness amount for ensuring the minimum thickness, and it is possible to realize weight saving of the meter hood and resource saving. .

Further, in this mold, the parison P is prevented from being caught in the contact portion, so that the operation trouble of the mold can be prevented. In the above embodiment, as shown in FIG. 2, when the push core 2 reaches the swing end, the first fluid outlet 1c is closed by the upper end surface of the push core 2, and as shown in FIG. In the state where the push core 2 reaches the linear movement end, the second fluid outlet 3b is closed by the lower end surface of the push core 2, so that the first and second
Although the low-pressure air supply from the fluid outlets 1c and 3b is stopped, the low-pressure air supply can be stopped by using a microcomputer.

In this case, although not shown, the tip end of the air blowing device and the mandrel of the blow molding machine, the linear motion hydraulic cylinder 4, the swinging hydraulic cylinder 6 and the first and second fluid outlets 1c and 3b of the mold. Sensors connected to the respective microcomputers are provided in the vicinity. Thus, the microcomputer has blow pressure P _x , parison internal pressure P ₀ ,
The push core position (x, y), the back pressure P _B1 near the first fluid outlet 1c, and the back pressure P _B2 near the second fluid outlet 3b are input.

Then, the microcomputer, as shown in FIG.
In step S100, the setting of blow pressure P _x is changed, and in step S101, the parison internal pressure P ₀ is read. Further, in step S102, the setting of the back pressure P _B1 near the first fluid outlet 1c is changed, and step S1
At 03, read back pressure P _B1 . And step S
In 104, it is judged whether or not the parison internal pressure P ₀ is equal to or higher than the back pressure P _B1. If NO, the process returns to step S100, and if YES, steps S105 and S105.
Proceed to 108.

In step S107, the pushing core position (x, y) is read, and the process proceeds to steps S108 and S110. In step S108, it is determined whether or not the push core 2 has reached the swing end, and if NO, step S108.
The process returns to 100, and if YES, step S109
Proceed to. Further, the setting of the back pressure P _B2 near the second fluid outlet 3b is changed in step S105, and the back pressure P _B2 is read in step S106. Then, in step S109, it is determined whether or not the parison internal pressure P ₀ is equal to or higher than the back pressure P _B2. If NO, the process returns to step S100, and if YES, the process proceeds to step S110. In step S110, after the push core 2 reaches the linear end,
It is determined whether or not n seconds have elapsed, and if NO, step S1
If the answer is YES, the process proceeds to step S111. In step S111, the back pressures P _B1 and P _B2 are reduced.

Thus, the back pressures P _B1 , P _B2 and the blow pressure P _x
Since the parison P is adjusted, the parison P is prevented from being caught in the contact portion between the front mold 1 and the push core 2 by the low pressure air blown out from the first and second fluid outlets 1c and 3b. It is surely blown between the first deep drawing surface 1a and the second deep drawing surface 2a.

[0031]

As described in detail above, since the deep drawing blow molding die of the present invention employs the structure described in the claims, it does not cause a defect and has a relatively long deep drawing portion. It is possible to mold a blow molded product having

[Brief description of drawings]

FIG. 1 is a cross-sectional view of essential parts of a deep-drawing blow molding die according to an embodiment.

FIG. 2 is a cross-sectional view of a main part of a deep-drawing blow molding die according to an embodiment.

FIG. 3 is a cross-sectional view of a main part of a deep-drawing blow molding die according to an embodiment.

FIG. 4 is a cross-sectional view of essential parts of a deep-drawing blow molding die according to an embodiment.

FIG. 5 is a sectional view of an essential part of a deep-drawing blow molding die according to an embodiment.

FIG. 6 is a time chart showing the operation of the deep drawing blow molding die of the embodiment.

FIG. 7 is a flowchart showing a part of the operation of the deep drawing blow molding die of another embodiment.

FIG. 8 is a sectional view of an essential part of a conventional deep-drawing blow molding die.

FIG. 9 is a sectional view of a main part of a conventional deep-drawing blow molding die.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Front type (1st type) 1a ... 1st deep drawing surface 2 ... Push core (2nd type) 2a ... 2nd deep drawing surface 1c, 3b ... Fluid outlet

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Muneharu Kato Muban, Tauraminato-cho, Yokosuka City, Kanagawa Kanto Automobile Industry Co., Ltd.

Claims (1)

[Claims] 1. A first die having a first deep-drawing surface extending in the deep-drawing direction, and a relative swing in a direction intersecting with the deep-drawing direction, and facing the first deep-drawing surface at a swing end. And a second die having a second deep drawing surface, and a deep drawing blow molding die for producing a contact portion where the contact between the first die and the second die is maintained after swinging of the second die. A mold for deep drawing blow molding, characterized in that a fluid outlet is formed at the contact portion.