JPH06862A - Sizing die for extrusion molding equipment - Google Patents

Abstract

PURPOSE:To produce a synthetic resin tubular body securely having a smooth surface. CONSTITUTION:A sizing die 2 for extrusion equipment is provided with a cylindrical body 21 through which a synthetic resin tubular body P extruded out of an extruder die 1 is to be passed. On the outer peripheral surface of the cylindrical body 21, a cooling water path 22a is formed in an inlet part thereof and suction slits 21a are formed in the other part. In this sizing die 2, grooves 21c communicating with the suction slits 21a through pores are formed on the inner peripheral surface of the inlet part of the cylindrical bode 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sizing die for externally shaping a synthetic resin tube extruded by an extrusion die into a regular tube shape.

[0002]

2. Description of the Related Art Conventionally, in a sizing die for an extrusion molding apparatus, a synthetic resin tube extruded from an extrusion die is generally shaped into a regular tube shape from the outside.

The structure of this conventional general sizing die will be described with reference to FIG. 4. The sizing die 101 has a cylindrical body 1 whose inner surface is formed on the shaping surface of a synthetic resin tube body 107.
03, and the tubular body 103 includes a tubular body 10
A water tank 104 that cools the outer periphery of No. 3 is attached.
The outer surface of the synthetic resin tube body 107 extruded from the extrusion die 102 is in close contact with the inner surface of the tubular body 103, and
An oil plate 105 is provided at the inlet of the tubular body 103 so that the tubular body 103 is cooled while sliding smoothly inside the tubular body 103, and the synthetic resin pipe body 107 is provided on the inner surface of the tubular body 103. There is provided a spiral slit 106 for creating a vacuum between the outer peripheral portion and the inner peripheral portion of the cylindrical body 103.

Explaining how to use the sizing die 101, the sizing die 101 is the extrusion die 10.
It is placed close to 2. The synthetic resin pipe body 107 extruded from the extrusion die 102 is applied to the outer surface of the synthetic resin pipe body 107 from the oil plate 105 provided at the inlet of the cylindrical body 103, and then the synthetic resin pipe body 107 is attached to the cylindrical body 103. enter. At this time, air is evacuated from the slit 106 between the inner surface of the cylindrical body 103 and the outer surface of the synthetic resin tube 107 to form a vacuum, so that the synthetic resin tube 107 is brought into close contact with the inner surface of the cylindrical body 103. While passing. While the synthetic resin tube body 107 is passing through the tubular body 103, the tubular body 103 is cooled from the outer peripheral portion by the water stored in the water tank 104,
As a result, the synthetic resin tubular body 107 is solidified and comes out of the tubular body in a regular tubular shape.

However, such a sizing die 101
The oil plate 105 is heated by the heat of the synthetic resin pipe body 107 while operating for a long time, the oil is seized and clogged, and the oil plate 105 and the synthetic resin pipe body 1 are
The contact resistance with 07 increases, and as a result, the synthetic resin tubular body 1
However, there is a problem in that it is impossible to stably pull 07, and annular irregularities are formed on the outer surface of the synthetic resin tube body 107, which lowers the product value.

As a method for solving such a problem, the applicant of the present application has previously described that, as described in Japanese Utility Model Publication No. 2-28039, instead of oil, the inner circumference of the inlet portion of the sizing die is used. I devised and applied for a sizing die with no seizure provided with cooling water passages.

[0007]

However, when a synthetic resin pipe body is manufactured using the sizing die of the invention described in Japanese Utility Model Publication No. 2-28039, the cooling water has no seizure and the contact resistance increases. Therefore, the annular irregularities were almost eliminated, but the irregularities on the outer surface of the synthetic resin tube were still slightly generated.

In view of the above problems, the present invention aims to provide a sizing die for an extrusion molding apparatus capable of reliably producing a synthetic resin tubular body having no irregularities on its outer surface.

[0009]

In order to achieve the above object, a sizing die for an extrusion molding apparatus of the present invention has a cylindrical body through which a synthetic resin tubular body extruded from an extrusion die passes, In a sizing die for an extrusion molding apparatus, in which a cooling water passage is formed on the outer periphery of the inlet of the tubular body and a suction slit is formed on the portion excluding the inlet, the inner periphery of the inlet of the tubular body In addition, a means is provided in which a groove communicating with the suction slit is formed.

[0010]

The synthetic resin tube extruded from the extrusion die enters the sizing die. The sizing die for the extrusion molding apparatus of the present invention communicates with the suction slit on the inner circumference of the inlet of the tubular body. Since the groove is formed, by sucking air from the suction slit, air is also sucked from the groove formed at the inlet of the tubular body. In other words, the synthetic resin tubular body has just come out of the extrusion die and is sucked from the vicinity of the inlet of the tubular body that is still in a soft state and adheres to the inner surface of the tubular body, so that a regular tubular shape with no unevenness Easily shaped.

Further, the inlet of the tubular portion is heated by the heat of the synthetic resin tube, but is cooled from the outer surface by the cooling water flowing in the cooling water passage formed on the outer periphery of the inlet of the tubular body. Since it is cooled, the surface resistance with the synthetic resin tube decreases,
Sliding of the synthetic resin tube is done smoothly.

[0012]

Embodiments of the present invention will now be described in detail with reference to FIGS. FIG. 1 is a sectional view showing a state in which a synthetic resin tubular body is extruded using a sizing die for an extrusion molding apparatus according to an embodiment, FIG. 2 is an enlarged sectional view of an essential part thereof, and FIG. -III is a sectional view.

In the figure, reference numeral 1 denotes an extrusion die attached to the tip of an extruder, and a synthetic resin is extruded in a tubular shape from the extrusion die 1.

Reference numeral 2 denotes a sizing die, which is arranged in the vicinity of the extrusion die 1 and is attached to the wall of the water tank 3. Further, the sizing die 2 has a cylindrical body 21 whose inner peripheral surface is formed so as to shape the synthetic resin pipe body P.
And a cooling ring 22 attached to the outer circumference of the inlet of the tubular body 21.

The tubular body 21 has a large number of suction slits 21a formed in the portion excluding the inlet portion, that is, the portion provided inside the water tank 3, and the inlet portion of the tubular body 21, that is, the water tank. 3 is connected to the inner circumference of the portion disposed outside 3 by the suction slit 21a and the small hole 21b.
The groove 21c of the strip is formed. In addition, the groove 21c
Are formed in an annular shape that is continuous in the circumferential direction of the tubular body 21. Further, as shown in FIG. 3, a plurality of the small holes 21b are formed at predetermined intervals.

The cooling ring body 22 is formed in the inner peripheral portion of the cooling water passage 22a so as to surround the tubular body 21 in the circumferential direction, and in the outer peripheral portion thereof.
Is provided with a cooling water introduction port 22b capable of introducing cooling water,
A cooling water discharge port 22c capable of discharging the cooling water in the cooling water passage 22a into the water tank 3 is provided on the side portion on the water tank 3 side. A plurality of the cooling water discharge ports 22c are formed at predetermined intervals.

Next, the operation of this embodiment will be described.

In the above structure, the synthetic resin tube P extruded from the extrusion port of the extrusion die 1 is introduced into the cylindrical body 21 of the sizing die 2. At this time, the suction slit 2 formed in the tubular body 21 of the sizing die 2
By sucking air from 1a, air is also sucked from the three grooves 21c formed at the inlet of the tubular body 21. That is, the synthetic resin pipe P is just ejected from the extrusion die 1 and is sucked from the vicinity of the inlet portion of the tubular body 21 which is still in a soft state, and is adhered to the inner surface of the tubular body 21 to be shaped.

The inlet of the tubular body 21 is heated by the heat of the synthetic resin pipe P, but the cooling water is flowing in the cooling water passage 22a formed on the outer periphery of the inlet of the tubular body 21. Since the water is cooled from the outer surface, the surface resistance with the synthetic resin pipe body P is reduced and the sliding of the synthetic resin pipe body P is made smooth. Even if the shaping operation is continued, the tubular body 2
Since the inlet portion of No. 1 is always kept in a low temperature state by the circulating cooling water, it does not become high temperature even if the heat of the synthetic resin pipe P is transmitted, and the synthetic resin pipe P always slides smoothly.

The synthetic resin tube P that has passed through the cylindrical body 21 of the sizing die 2 is further completely cooled and solidified by the water in the water tank 3.

That is, in the sizing die of this embodiment, the synthetic resin pipe P which has just come out of the extrusion die 1 and is still in a soft state can be shaped by adhering it to the inner surface of the cylindrical body 21. Therefore, the synthetic resin pipe P can be easily formed into a regular pipe shape without irregularities.

Since the groove 21c communicates with the suction slit 21a, a vacuum tube (not shown) for sucking air may be connected only to the suction slit 21a so that the structure is not complicated. You can

Although the embodiment of the present invention has been described in detail above with reference to the drawings, the specific structure is not limited to this embodiment, and there are design changes and the like within a range not departing from the gist of the present invention. Also included in the present invention. For example, in the embodiment, three grooves are provided at the inlet of the tubular body, but the number of grooves is
The spacing may be narrowed and increased. Further, the groove may be formed in a spiral shape.

[0024]

As described above, in the sizing die for the extrusion molding apparatus of the present invention, while the synthetic resin tube body is still soft, the synthetic resin tube body is brought into close contact with the inner peripheral surface of the cylindrical body to form a regular tube shape. Since it is extruded in this state, it is possible to obtain an effect that a synthetic resin tubular body having a regular tubular shape with no gloss on the outer surface can be manufactured.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a state where a synthetic resin tube is extruded using a sizing die for an extrusion molding apparatus of this example.

FIG. 2 is an enlarged sectional view of the sizing die shown in FIG.

3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a cross-sectional view showing a state in which a synthetic resin tube is extruded using a conventional sizing die.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Extrusion die 2 Sizing die 21 Cylindrical body 21a Suction slit 21c Groove P Synthetic resin tubular body

Claims (1)

[Claims] 1. A cylindrical body for passing a synthetic resin pipe extruded from an extrusion die, wherein a cooling water passage is formed on the outer periphery of an inlet portion of the cylindrical body, and a portion excluding the inlet portion. In a sizing die for an extrusion molding apparatus in which a suction slit is formed, a groove communicating with the suction slit is formed on the inner circumference of the inlet portion of the tubular body. Sizing die.