JP3134441B2 - Parison mold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a parison mold used for injection blow molding suitable for producing resin boots, resin containers and the like, and more particularly, to a cooling method for partially cooling a parison. The present invention relates to a parison mold having a nest.

[0002]

2. Description of the Related Art Injection blow molding of this kind
Generally, the following operation is performed using an injection blow molding apparatus 10 as shown in FIG.

First, using a parison mold 300, a core 5
The parison 70 is injection-molded on the top of the mold. Next, the formed parison 70 is placed together with the core 50 in the blow mold 40, and air pressure is applied to the parison 70 from the inside to form the parison 70 into a desired shape. Next, the shaped parison 70 is released from the core 50. Thereafter, the temperature of the core 50 is adjusted in preparation for the next molding. The released parison 70
After undergoing predetermined processing, it is made into a product.

[0004] Conventionally, a parison mold 300 having two split molds 30 as shown in FIG. 5 has been used. Hereinafter, this conventional parison mold 30 will be described.
0 will be described.

The split molds 30 form the cavity 34 together with the core 50. The cavity 34 is for receiving the molten resin injected from the injection unit 20 and forming the parison 70.

Each split mold 30 includes a split mold body 31 heated by a heater and a cooling insert 3 fixed in the split mold 31.
It has 2.33. The cooling inserts 32 and 33 are provided with water holes 35 for flowing cooling water. The cooling inserts 32 and 33 are provided for sufficiently cooling and solidifying the parison 70 formed in this portion, and preventing the parison 70 in the portion from being deformed in the next blowing step. Cooling insert 32
A recess is provided around 33 to reduce heat transfer with the split mold body 31.

Reference numeral 36 denotes a sprue.

[0008]

However, in the above-mentioned conventional parison mold 300, since the cooling inserts 32 and 33 are always in contact with the split mold main body 31, the heat transfer is large, and at the boundary between the two. The cooling inserts 32 and 33 had higher temperatures than the set temperature, and the split mold main body 31 had a lower temperature than the set temperature.

Then, such a parison mold 300
Since the parison 70 formed by the above method has a similar temperature distribution, the parison 70 in the portion formed by the cooling inserts 32 and 33 is not sufficiently solidified, and may be deformed in the blowing step, or conversely, may be split. There is a problem that the viscosity of the parison 70 in the portion formed by the mold main body 31 increases and the shape is not sufficiently formed in the blowing step.

[0010]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is directed to a parison molding die used for injection blow molding and comprising a plurality of split dies. Having a cooling insert disposed in the split mold main body to partially cool the parison, and a floating device that floats the cooling insert from the split mold main body when the mold is opened to provide a gap therebetween. A parison mold having the following features is employed.

[0011]

According to the parison mold of the present invention, a cooling insert for partially cooling the parison is floated from the split mold main body when the mold is opened, and a gap is provided between the split mold main body and the cooling insert. Has a floating device.

Therefore, when the mold is opened, the heat transfer between the cooling insert and the split mold can be prevented by the gap, and the deviation from the set temperature at the boundary between them can be reduced. In the parison molded by the parison mold of the present invention, the part formed by the cooling insert is sufficiently cooled and solidified, and the part mainly formed by the split mold has a sufficiently low viscosity. Problems in the blowing process can be eliminated.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

The parison mold 300 of this embodiment is for molding a parison 70 for a constant velocity joint boot of an automobile. The parison mold 300 is composed of two split dies 30 having the same structure. It is defined.

Each split mold 30 includes a split mold body 31 heated to 125 ° C. by a heater (not shown) and cooling inserts 32 and 37 set to 55 ° C. by cooling water. And

The split main body 31 is for forming a central portion (formed in a bellows shape in a blowing step) of the parison 70, and the cooling inserts 32 and 37 are formed at inner ends of both ends of the parison 70. This is for forming ribs (which become sealing ribs in a finished boot product) and the like. One cooling insert 3
2 is fixed to the split mold body 31 as in the prior art,
The other cooling insert 37 is disposed in the split main body 31 so as to be movable in the vertical direction in the drawing.

The cooling insert 37 has four side surfaces inclined with respect to the mold cutting direction (vertical direction in the figure). Cooling insert 37
A compression coil spring 38 is disposed between the main body 31 and the split main body 31 and urges the two in a direction away from each other. Split mold 3
A pin 39 with a head penetrating through the cooling insert 37 is fixed to 1, and the movement stroke of the cooling insert 37 is regulated by the head of the pin 39. In this embodiment, a floating device is constituted by the pin 38 and the compression coil spring 38.

Further, the cooling insert 37 has a nipple 80 projecting from the side surface of the split mold 31 and connected to the water passage hole 35, so that cooling water can pass therethrough. In addition, split mold subject 3
In order to allow the cooling insert 37 to move up and down together with the nipple 80, a hole 81 having a larger diameter than the nipple
Is provided.

Next, a molding process using the parison mold 300 will be described.

First, the parison mold 300 is shown in FIGS.
Open the mold as shown in the figure. Then, the cooling insert 37 of each split mold 30 moves in a direction away from the split mold main body 31 by the action of the spring 38. At this time, since all the side surfaces of the cooling insert 37 are inclined, the cooling insert 31 is floated and supported by the split mold main body 31, that is, the cooling insert 37 and the split mold main body 31.
A gap 90 is formed between them. Therefore, in this mold open state, the cooling insert 37 and the split mold body 31
There is almost no heat transfer between them.

Next, the core 50 is disposed between the split dies 30, and the mold is clamped. (See FIG. 3) Then, the cooling insert 37 floating by the spring 38 is seated on the split mold main body 31 by the mold clamping force, and the cooling insert 37 and the split mold main body 31
0 and a continuous cavity 34 is formed.

Thereafter, a molten resin is injected from the sprue 36 into the cavity 34 to form the parison 70, the mold is opened, the parison 70 is transferred to the blow step together with the core 50, and air pressure is applied to the parison 70 from the inside. Form into a predetermined shape.

In the present embodiment, when the mold is opened, a gap 90 is formed between the cooling insert 37 and the split mold main body 31, so that almost no heat transfer occurs between them and the two are brought to the set temperature. Very close temperature can be maintained. Therefore, in the parison 70 formed by the parison mold 300, the portion formed by the cooling insert 37 is sufficiently cooled and solidified, and the split mold main body 31 is formed.
Since the portion formed by the above has a sufficiently low viscosity, the bellows of the boot can be formed sufficiently without deformation of the inner peripheral rib during the blowing step.

In the present embodiment, the floating device having the simplest structure including the spring 38 and the head pin 39 has been described. However, even if a hydraulic mechanism, a cam mechanism synchronized with opening and closing of the mold, or the like is used, Similar effects can be obtained.

Although the cooling insert 32 of this embodiment is fixed, the cooling insert 32 may be configured to float.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a parison mold according to an embodiment of the present invention in an open state.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a sectional view showing the mold closed state of the embodiment.

FIG. 4 is an explanatory diagram of injection blow molding.

FIG. 5 is a sectional view showing a closed state of a conventional parison mold.

[Explanation of symbols]

 Reference Signs List 300 parison mold 30 split mold 31 split mold main body 32, 33, 37 cooling insert 38 spring constituting floating device 39 headed pin constituting floating device 90 clearance

Continuation of the front page (51) Int.Cl. ⁷ identification code FI // B29L 22:00 (58) Investigated field (Int.Cl. ⁷ , DB name) B29C 49/00-49/80 B29B 11/08 B29C 33/00-33/76

Claims (1)

(57) [Claims] 1. A parison mold used for injection blow molding and comprising a plurality of split molds, wherein the split mold has a split mold main body and a split mold main body for partially cooling the parison. A parison mold comprising: a cooling insert disposed therein; and a floating device for lifting the cooling insert from the split mold main body when the mold is opened to provide a gap therebetween.