JP2001260211A - Sizing device for extruded moldings and method for controlling outside diameter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sizing device for extruded moldings and a method for controlling an outside diameter, in which control of the outside diameter of the extruded moldings is performed easily and rapidly. SOLUTION: The sizing device for the extruded moldings is equipped with a sizing die 7 having a hole part 6 for passing the extruded moldings P which consist of an internal conductor 2 extruded from a cross head 1, a cordelle cord (twisted cord) 4 and an insulated tube 5. The sizing device is provided with a reciprocating position regulating means 11 which approachs the sizing die 7 to the cross head 1 and separates the former from the latter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sizing apparatus and an outer diameter control method for an extruded product formed by inserting an extruded product into a predetermined outer diameter.

[0002]

2. Description of the Related Art Conventionally, an insulating core wire of a coaxial cable has been
The inner conductor is inserted into the crosshead, and the molten resin is extruded from the crosshead, a cordel cord is spirally wound around the inner conductor, and the inner conductor and the cordel cord are covered with an insulating tube. It has been manufactured by extruding and then extruding a molded product (insulated core wire) into a sizing device provided on the downstream side of the crosshead to form it into a predetermined outer diameter and solidify it by cooling.

This sizing apparatus has a sizing die having a hole through which an extruded product is inserted, and the inner diameter of the hole of the sizing die is set to be substantially equal to the outer diameter of a desired extruded product. ing.

[0004]

However, even when the same sizing die is used, the outer diameter of the formed extruded product may not be constant and may slightly change. For this reason, a plurality of sizing dies having slightly different inner diameters are required to be prepared and appropriately selected and used to adjust the outer diameter of the extruded product so as not to vary, thereby complicating the operation.

Accordingly, an object of the present invention is to provide a sizing apparatus and an outer diameter control method for an extruded product which can easily and quickly control the outer diameter of the extruded product.

[0006]

In order to achieve the above-mentioned object, a sizing apparatus for an extruded product according to the present invention extrudes a molten resin while inserting an inner conductor into a spiral shape around the outer periphery of the inner conductor. An extruded product is provided on the downstream side of a crosshead in which a cordel string is wound around and the inner conductor and the cordel string are covered with an insulating tube, and the inner conductor, the cordel string and the insulating tube are provided. In a sizing apparatus for an extruded product provided with a sizing die having a hole to be inserted, a reciprocating position adjusting means for moving the sizing die closer to and away from the crosshead,
It is provided.

Further, according to the method for controlling the outer diameter of an extruded product according to the present invention, the inner conductor is inserted into the crosshead, and the molten resin is extruded from the crosshead so as to be spirally formed on the outer peripheral side of the inner conductor. The extruded product is formed by winding a cordel cord and covering the inner conductor and the cordel cord with an insulating tube to form an extruded product, and then passing the extruded product through the hole of the sizing die on the downstream side of the crosshead. In the outer diameter control method described above, the position of the sizing die is adjusted by moving the sizing die toward and away from the crosshead while inserting the extruded product.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings showing embodiments.

FIG. 1 shows an embodiment of a sizing apparatus for an extruded product according to the present invention.
Is provided downstream of the crosshead 1 for extruding the extruded product P. Specifically, this crosshead 1
A cordel string 4 is wound around the outer periphery of the inner conductor 2, and the inner conductor 2 and the cordel string 4 are covered with an insulating tube 5.
This is for extruding an insulated core wire P 'of a coaxial cable (see FIG. 3). In addition, cordel string 4 and insulating tube 5
Are the same material, for example, made of a resin such as polyethylene, and the internal conductor 2 is made of, for example, an aluminum pipe or a copper pipe.

Thus, the sizing device A holds the sizing die 7 having the hole 6 through which the extruded product P composed of the inner conductor 2, the cordel string 4 and the insulating tube 5 is inserted (runs), and the sizing die 7. With cooling water 8
Water tank 9 for accommodating the sizing die 7 and the hole 6
Film forming means 10 for forming a water film between the product and the extruded product P
And a reciprocating position adjusting means 11 for bringing the sizing die 7 together with the cooling water tank 9 toward and away from the crosshead 1.

As shown in FIGS. 1 and 2, the sizing die 7 has a cylindrical shape having an outer flange 12 on the outer peripheral surface at the end on the crosshead 1 side. A round portion 13 is formed along the opening edge. Then, the body 14 of the sizing die 7 is inserted into the hole in the downstream side wall of the cooling water tank 9.
Is inserted, and the outer flange 12 is connected to the downstream side wall by bolt / nut coupling.

The water film forming means 10 is formed in an annular slit 15 formed in the inner peripheral surface of the hole 6 in the vicinity of the round portion 13 of the sizing die 7, and in a body 14 communicating with the annular slit 15. An annular flow path 16; and a water supply flow path 17 formed in the outer flange 12 communicating with the annular flow path 16.
Is connected to a water supply source (not shown) via a connection pipe 18. In other words, the water W is supplied to the water supply flow path 17 and is jetted from the annular slit 15 toward the hole 6, so that the water W is formed between the extruded product P passing through the hole 6 and the inner peripheral surface of the hole 6. It is configured to form a film. Note that a plurality of annular slits 19 are also provided downstream of the annular slit 15 communicating with the connection pipe 18,
The slits 19 may be communicated with the outer peripheral surface of the body 14 so that the cooling water 8 in the cooling water tank 9 flows into the hole 6.

The reciprocating position adjusting means 11 includes a guide rail 20 provided in the longitudinal direction, a support table 21 supporting the cooling water tank 9 and slidably provided on the guide rail 20, and a guide rail 20. A screw shaft 22 rotatably provided around a horizontal axis parallel to the shaft, a motor M for driving the screw shaft 22 to rotate, a nut member 23 fixed to the support table 21 and screwed to the screw shaft 22. When the screw shaft 22 rotates forward and backward by the motor M, the support base is
21 is configured to reciprocate in a direction approaching / separating from the crosshead 1.

Next, a method of controlling the outer diameter of the extruded product P by the sizing device A will be described with reference to FIGS. That is, the inner conductor 2 is inserted into the center hole 24 of the crosshead 1 and moved to the downstream side, and the first extrusion port 25 and the die
28, the molten resin 3 and 3 are simultaneously extruded from the second extrusion port 26, a cordel cord 4 is spirally wound around the outer periphery of the inner conductor 2, and the inner conductor 2 and the cordel cord 4 are connected with the insulating tube 5. By coating, the extruded product P (insulated core wire P ') is continuously formed.

Thereafter, the extruded product P, which has been extruded, is inserted into the hole 6 of the sizing die 7 of the sizing device A and formed into a predetermined outer diameter D substantially equal to the inner diameter of the hole 6. That is, the outer diameter dimension D ₀ of the insulating tube 5 immediately after being extruded from the second extrusion port 26 of the cross head 1 is large (for example, 60 mm). The diameter is reduced to D (for example, 43 mm). At this time, a water film is formed between the extruded product P and the hole 6 by the water W jetted from the annular slit 15 provided in the sizing die 7, and the extruded product P is formed by the water film. Can be passed smoothly.

After that, the extruded product P that has passed through the sizing die 7 passes through the cooling water 8 in the cooling water tank 9 to be cooled and solidified, and its outer diameter D is slightly larger or smaller than the standard value. (For example, an error of about ± 0.3 mm from the standard value may occur). In the outer diameter control method of the present invention, the sizing die 7 is moved toward and away from the crosshead 1 while inserting the extruded product P in order to reduce a delicate error of the outer diameter D of the extruded product P. Adjust the position.

That is, at the time of extrusion molding, the outer diameter D of the extruded product P is measured. If the measured value is larger than the standard value, the support 21 of the reciprocating position adjusting means 11 is moved to the crosshead 1.
When the measured value is smaller than the standard value, the support 21 is moved in a direction away from the crosshead 1.

That is, the insulating tube 5 immediately after being extruded from the second extrusion port 26 of the crosshead 1 is in a hot and soft state, and is easily deformed as the time until it is inserted into the sizing die 7 becomes shorter. The longer the time until it is inserted into the die 7, the cooler it becomes and the more difficult it becomes to deform. At this time, it is considered that the pressure of the water W ejected from the annular slit 15 of the sizing die 7 acts on the deformation of the insulating tube 5.

As described above, by finely adjusting the position of the sizing die 7, the outer diameter of the extruded product P can be controlled, and a stable extruded product P (insulated core wire P) having a small variation in outer diameter can be obtained. ') Can be made.

The present invention is not limited to the above-described embodiment. For example, the support table 21 may be slid by a cylinder as the reciprocating position adjusting means 11. Also,
In the present embodiment, the case where the insulated core wire P ′ in which one cordel cord 4 is spirally wound around the inner conductor 2 from the crosshead 1 is manufactured, but a plurality of cords such as two cords or three cords are produced. The present invention can be applied to the case where an insulated core wire around which a cordel cord is wound is manufactured. An outer diameter measuring means for measuring the outer diameter of the extruded product P is provided downstream of the cooling water tank 9, and the motor M of the reciprocating position adjusting means 11 is automatically controlled by a control signal from the outer diameter measuring means. To configure
preferable.

[0021]

Since the present invention is configured as described above, the following effects can be obtained.

According to the first or second aspect, the extruded product P extruded from the crosshead 1 and reduced in diameter by inserting the sizing die 7 is stabilized to a predetermined outer diameter D without variation. Can be manufactured. At this time,
By adjusting the position of the sizing die 7, the outer diameter of the extruded product P can be easily and quickly controlled.

[Brief description of the drawings]

FIG. 1 is a partially sectional front view showing an embodiment of a sizing apparatus for an extruded product according to the present invention.

FIG. 2 is a sectional front view showing a sizing die.

FIG. 3 is a cross-sectional view showing an extruded product.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Crosshead 2 Inner conductor 3 Molten resin 4 Cordel string 5 Insulation tube 6 Hole 7 Sizing die 11 Reciprocating position adjusting means P Extruded product

Continued on the front page (72) Inventor Akito Nishitsuboshi 37, Ishizukawari 37, Shirokata-cho, Fukui-shi, Fukui Prefecture Mitsui Electric Wire & Cable Co., Ltd. Fukui Works (72) Ryutaro Hori 37, Shirakata-cho, Fukui-shi 6-1 Ishizuka-wari F-term (reference) 4F207 AA04 AD03 AD05 AG14 AH35 AR07 KA01 KB18 KK76

Claims (2)

[Claims] 1. A crosshead in which a molten resin is extruded while an inner conductor is inserted, a cordel cord is spirally wound around the outer periphery of the inner conductor, and the inner conductor and the cordel cord are covered with an insulating tube. In a sizing apparatus for an extruded product provided with a sizing die having a hole through which an extruded product comprising the inner conductor, the Cordel string, and the insulating tube is inserted, the sizing die is provided. A sizing apparatus for an extruded product, comprising a reciprocating position adjusting means for approaching and separating from the crosshead. 2. An inner conductor is inserted through a crosshead, and a molten resin is extruded from the crosshead to spirally wind a cordel cord around the outer periphery of the inner conductor. Is coated with an insulating tube to form an extruded product, and then the extruded product is inserted in the outer diameter control method of inserting the extruded product into the hole of the sizing die on the downstream side of the crosshead. A method for controlling the outer diameter of an extruded product, wherein the position is adjusted by moving the sizing die closer to or away from the crosshead while adjusting the position.