JP2001026043A - Nozzle structure of extruder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the nozzle structure of an extruder effectively preventing the stagnation of a resin in each part and reducing the loss of the resin. SOLUTION: A nozzle 25 has a cone-shaped inflow guide passage 2 6a gradually reduced in its diameter for guiding the resin extruded through a breaker plate 24, and an outflow guide passage 26b for guiding the resin to a die from the downstream end on the fine diameter side of the inflow guide passage 26a. A barrier wall member 30 having axial length slightly shorter than the axial length of the inflow guide passage 26a is mounted in the inflow guide passage 26a. The wall member 30 has the conical holding part 30a fitted and held to the conical inner peripheral surface on the downstream side of the inflow guide passage 26a and having a corresponding almost conical shape, and a barrier wall expanded part 30c gradually expanding in the direction of the breaker plate 24 with respect to a center direction from the upstream peripheral edge 30b of the conical holding part 30a. A plurality of the dispersed guide grooves 30d ranging from the barrier wall expanded part 30c to the total length of the conical holding part 30a are formed to the outer peripheral surface of the barrier wall member 30, so as to be spaced apart from each other in the peripheral direction thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a nozzle structure of an extruder for extruding and coating a resin on a filament such as a covered electric wire.

[0002]

2. Description of the Related Art As shown in FIG. 7, for example, as shown in FIG. 7, a core portion 1, an inner layer coating portion 2 made of PVC (polyvinyl chloride) or the like for coating the outer periphery of the core portion 1, and an outer periphery of the inner layer coating portion 2 are formed. And a pair of striped layers 4 formed on the surface side in an elongated shape along the longitudinal direction of the core wire portion 1. The coated wire 5 is different from the coating layer 3 and the striped layer 4. Coloring was performed, and the combination of those colors was used to identify the wire type and wire size of the covered wire 5.

When manufacturing the covered electric wire 5, as shown in FIG. 8, an extruder 9 for the inner layer covered portion 2 is provided around the outer periphery of the core wire 1 guided along the core wire guide hole 7a of the die 7. And the outer periphery thereof is further coated with the resin extruded from the extruder 10 for the coating layer 3. When coating the outer periphery of the inner layer coating portion 2 with the coating layer 3, the resin extruded from the extruder 11 for the stripe layer 4 is interposed in the coating layer 3, so that the coated electric wire 5 having the stripe layer 4 is formed. Had been manufactured.

The structures of the extruders 9, 10 and 11 are substantially the same, and for example, as shown in FIG. 9, the extruders 9 are brought into a molten state by rotating a screw 15 in the extruder body 14. The resin flows through a number of flow holes 16 a of the breaker plate 16 through the resin guide path 18 of the nozzle 17.
And is guided to the die 7 side through the resin guide path 18.

[0005]

However, the resin guide path 18 of the nozzle 17 has a conical inflow guide path 18a having a gradually decreasing diameter for guiding the resin extruded through the breaker plate 16, and the inflow guide path 18a. Small-diameter outflow guide path 1 that guides the resin from the small-diameter downstream end to the die 7 side
8b, the resin is extruded from the respective flow holes 16a of the breaker plate 16 into the inflow guide passage 18a having a large volume, and the pressure on the resin outflow side of the breaker plate 16, that is, in the inflow guide passage 18a. , The flow of the resin becomes non-uniform, and the flow of the resin at the outer peripheral portion of the inflow guide path 18a is reduced, causing a problem of stagnation of the resin.

Therefore, as in the structure disclosed in JP-A-8-57937, a conical ridge is formed on the resin outflow side of the breaker plate, and the conical ridge is formed by the inflow guide passage 18a.
By entering into the mortar-shaped resin inflow portion corresponding to the above, a structure that prevents a sudden decrease in pressure in the flow of the resin, smoothes the flow of the resin extruded through the breaker plate, and prevents the stagnation of the resin. Proposed.

However, the structure disclosed in the above publication has a structure in which a circular hole through which the resin is extruded is not located at the center of the breaker plate but is distributed only at the outer peripheral portion due to the presence of the conical ridge. The resin extruded from the extruder body by the rotation of the screw is limited to a circular hole on the outer peripheral portion of the breaker plate, and the flow of the resin on the extruder body side extruded by the rotation of the screw causes a bias,
There was a possibility that stagnation might occur in the resin flow on the extruder body side.

Accordingly, an object of the present invention is to provide a nozzle structure of an extruder that effectively prevents resin from remaining in each part and reduces resin loss.

[0009]

Technical means for solving the above problems include a conical inflow guide path having a gradually decreasing diameter for guiding resin extruded from an extruder through a breaker plate, An extruder having an outflow guideway for guiding the resin from the downstream end of the guideway toward the die from the small-diameter side downstream end, wherein the inflow guideway has an axial direction slightly shorter than its axial length. A barrier member having a length is mounted, the barrier member has a corresponding substantially conical cone holding portion fitted and held on the conical inner peripheral surface on the downstream side of the inflow guide path, and A barrier bulging portion gradually bulging in the direction of the breaker plate from the upstream peripheral edge toward the center, and a dispersion guide groove extending from the barrier bulging portion to the entire length of the conical holding portion is formed on the outer peripheral surface of the barrier member. Formed in multiple directions To the point where the Te there.

[0010] Further, in the vicinity of the upstream peripheral edge of the conical holding portion, the peripheral edge of each of the dispersion guide grooves on the barrier bulging portion side becomes gradually wider with respect to the upstream peripheral edge direction of the conical holding portion. As a structure, the peripheral edge of each of the dispersion guide grooves on the side of the conical holding portion extending from the upstream peripheral edge in the direction of the outflow guide path is formed to be gradually narrower in the direction of the outflow guide path. Is also good.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a cross-sectional view of a main part of an extruder 21. The resin melted by the rotation of the screw 23 is extruded into the resin guide path 26 of the nozzle 25 through the many flow holes 24a of the breaker plate 24, and the resin guide path 2
It is configured to be guided to the die side through 6.

The resin guide path 26 also has a conical inflow guide path 26a having a gradually decreasing diameter for guiding the resin extruded through the breaker plate 24, and a small-diameter downstream end of the inflow guide path 26a. And a small-diameter outflow guide path 26b for guiding the resin to the die side.

In this embodiment, the inflow guide path 26
A substantially streamlined barrier member 30 having an axial length slightly shorter than the axial length is mounted in a.

As shown in FIGS. 2 and 3, the barrier member 30 has a corresponding substantially conical cone holding portion 30a fitted and held on the conical inner peripheral surface on the downstream side of the inflow guide passage 26a. And the upstream peripheral edge 3 of the conical holding portion 30a.
The barrier bulge portion 30c gradually bulges in the direction of the breaker plate 24 from the center direction from 0b. In the present embodiment, the cone holder 3
Reference numeral 0a denotes a structure having an axial length of about 2/3 of the axial length of the inflow guide path 26a.

On the outer peripheral surface of the barrier member 30, a plurality of dispersion guide grooves 30d extending from the barrier bulging portion 30c to the entire length of the conical holding portion 30a are spaced at regular intervals in the circumferential direction (three in this embodiment). Is formed.

The present embodiment is configured as described above, and the barrier member 30 is provided in the inflow guide passage 26a of the nozzle 25.
Are inserted and arranged with the conical holding portion 30a side as the downstream side of the resin flow. Then, in this state, if the screw 23 on the extruder main body 22 side is driven to rotate, the rotation causes the resin to be extruded from the extruder main body 22 side into the inflow guide passage 26a through the respective flow holes 24a of the breaker plate 24, Due to the extrusion pressure of the resin, the inflow guide path 26a
The barrier member 30 inserted and disposed inside is pushed in the downstream direction, and the conical holding portion 30 is formed on the inner peripheral surface of the inflow guide passage 26a.
a is held in a fitted state in which the outer peripheral surface of the a contacts.

In this state, the breaker plate 24
When the resin is sequentially extruded through each of the flow holes 24a, the extruded resin is dispersed and guided to the outer peripheral portion of the inflow guide passage 26a by the barrier member 30 bulging in the direction of the breaker plate 24, and thereafter, each of the dispersed guides is dispersed. It is guided to the outflow guide path 26b through the groove 30d, and is guided to the die side through the outflow guide path 26b.

That is, in the conventional structure in which the barrier member 30 does not exist, when the resin is extruded through the respective flow holes 16a of the breaker plate 16, the space on the resin outflow side of the breaker plate 16, that is, in the inflow guide path 18a, That is, since the volume is increased, the pressure is suddenly reduced, and the flow of the resin becomes non-uniform, and the flow of the resin at the outer peripheral portion of the inflow guide path 18a is reduced, causing the resin to stay and causing the burning of the resin. However, in the present embodiment, the inflow guideway 26a
The barrier member 30 is mounted in the inside, and the barrier bulging portion 30c of the barrier member 30 facing the breaker plate 24 has a structure bulging at the center in the direction of the breaker plate 24. When the resin is extruded into the inflow guide path 26a through the flow hole 24a, even if the pressure suddenly decreases, the extruded resin is moved along the outer surface of the bulging barrier member 30 along the inflow guide path. The outflow guide path 2 is distributed and guided by the outer periphery of the inflow guide path 26a, and is distributed through the respective dispersion guide grooves 30d located on the outer circumference of the inflow guide path 26a.
Since the resin is forcibly guided to the side 6b, the stagnation of the resin can be effectively prevented, and the occurrence of resin burn due to partial stagnation of the resin can also be prevented.

Further, the resin is extruded toward the inflow guide passage 26a from the flow holes 24a distributed throughout the inner and outer peripheral portions of the breaker plate 24. Stagnation can also be effectively prevented.

Further, the barrier member 30 is connected to the inflow guide path 26a.
Is supported in a three-way fitting manner on the inner peripheral surface of the device, so that the holding state is also stable.

The coating layer 3 and the stripe layer 4
In the case of changing the color of the wire, it is necessary to extrude and discharge the resin before replacement remaining in the resin guide path 26 with the resin after replacement before manufacturing the product of the insulated wire 5. In this case, the inflow guide path 26 a When the barrier member 30 is mounted in the inside, the internal volume in the inflow guide path 26a is reduced, and the post-replacement resin required for extruding and discharging the pre-replacement resin, so-called overflow resin, is reduced. At this time, since the stagnation of the resin is effectively prevented by the barrier member 30, the extruding and discharging of the resin before the replacement is performed more smoothly, and in this respect, the overflow resin is reduced.

Further, at the initial stage of the color change, the kneading of the colorant and the resin is poor, and the flow holes 2
4a, the resin is effectively prevented from staying in the inflow guide path 26a, so that poorly kneaded resin does not stay in the inflow guide path 26a forever, and the poorly kneaded resin can be smoothly discharged. The output loss at the start of the production line after the replacement can be reduced.

FIGS. 4 to 6 show a second embodiment, in which the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

That is, in the present embodiment, the cone holding portion 30a
Near the upstream peripheral edge 30b of the barrier bulge 3
The peripheral edge of each dispersion guide groove 30d on the 0c side is the upstream peripheral edge 3d.
0b, the peripheral edge of each dispersion guide groove 30d on the side of the conical holding portion 30a extending from the upstream peripheral edge in the direction of the outflow guide path 26b gradually increases with respect to the outflow guide path direction. As shown in FIG. 4, the dispersion guide grooves 30d are formed to be narrow, and the periphery of each dispersion guide groove 30d is located at the position of the upstream periphery 30b.
And a structure in contact with the peripheral portion.

The periphery of each dispersion guide groove 30d is configured to have a smooth curved surface in the groove bottom direction near the upstream peripheral edge 30b.

Therefore, in the present embodiment, even in the outer peripheral portion of the barrier bulging portion 30c between the respective dispersion guide grooves 30d, the dispersion is smoothly guided in the respective dispersion guide grooves 30d, and the resin is more effectively prevented from being retained. There are advantages that can be done.

In the above embodiment, the color change of the coating layer 3 and the stripe layer 4 is exemplified.
The process may be performed at the time of changing the resin of the inner-layer covering portion 2, and the present invention is not limited to the case where the inner covering portion 2 is used for manufacturing the covered electric wire 5 as described in the embodiment.

The number, depth and width of the dispersion guide grooves 30d may be determined as needed.

[0029]

As described above, according to the nozzle structure of the extruder of the present invention, the extruder nozzle structure is formed such that the resin extruded through the breaker plate is introduced into the conical inflow guide path having a gradually decreasing diameter, and the axial direction of the inflow path. A barrier member having an axial length slightly shorter than the length is mounted, the barrier member being a corresponding generally conical cone holder fitted and retained on the conical inner peripheral surface downstream of the inflow guideway. And a barrier bulging portion gradually bulging in the direction of the breaker plate from the upstream peripheral edge of the conical holding portion toward the center of the breaker plate. A plurality of distributed guide grooves over the entire length are formed circumferentially separated from each other,
When the resin is extruded into the inflow guide path through each of the flow holes in the breaker plate, even if the pressure suddenly decreases, the extruded resin is guided along the outer surface of the bulging barrier member. The resin is dispersedly guided on the outer periphery of the road, and is forcibly guided to the outflow guideway side through the respective dispersion guide grooves located on the outer periphery of the inflow guideway, so that the resin can be effectively prevented from remaining in each part, and the partial resin can be retained. There is an advantage that the occurrence of resin burn due to the above can be prevented.

Further, when the resin before replacement remaining in the resin guide path is extruded and discharged by the overflow resin at the time of resin change in a work change or the like, if the barrier member is installed in the inflow guide path, the inflow guide Since the internal volume in the road is reduced, the amount of overflow resin required for extruding and discharging the pre-replacement resin is reduced, and the retention of the resin is effectively prevented by the barrier member. From this point, it is possible to reduce the amount of overflow resin, and furthermore, it is possible to discharge the poorly kneaded resin efficiently and smoothly, to reduce the discharge loss at the start of the production line, and to effectively reduce the resin loss. There is.

Further, in the vicinity of the upstream peripheral edge of the conical holding portion, the peripheral edge of each of the dispersion guide grooves on the barrier bulging portion side is formed to be gradually wider with respect to the upstream peripheral edge direction of the conical holding portion. If the peripheral edge of each of the dispersion guide grooves on the side of the conical holding portion extending from the upstream peripheral edge in the direction of the outflow guide path is formed to be gradually narrower in the direction of the outflow guide path, each dispersion guide groove In the outer peripheral portion of the barrier bulging portion between the
There is an advantage that the dispersion is smoothly guided in each of the dispersion guide grooves, and the stagnation of the resin can be more effectively prevented.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a main part showing a first embodiment of the present invention.

FIG. 2 is a view of the barrier member in FIG. 1 taken along the line II-II.

FIG. 3 is a view of the barrier member in FIG. 1 taken along line III-III.

FIG. 4 is a sectional view of a main part showing a second embodiment.

5 is a view of the barrier member in FIG. 4 taken along line VV.

6 is a view of the barrier member in FIG. 4 taken along line VI-VI.

FIG. 7 is a perspective view of a main part of the covered electric wire.

FIG. 8 is a schematic explanatory view of an extruder for producing a covered electric wire.

FIG. 9 is a partial sectional view of a conventional extruder.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 21 Extruder 22 Extruder main body 23 Screw 24 Breaker plate 24a Flow hole 25 Nozzle 26 Resin guideway 26a Inflow guideway 26b Outflow guideway 30 Barrier member 30a Conical holding part 30b Upstream peripheral edge 30c Barrier bulge part 30d Dispersion guide groove

Claims (2)

[Claims] 1. A conical inflow guideway having a gradually decreasing diameter for guiding the resin extruded from an extruder through a breaker plate, and an outflow for guiding the resin from a downstream end of the inflow guideway to a die side. A nozzle member having an axial length slightly shorter than the axial length in the inflow guide channel, wherein the barrier member includes an inflow guide. A corresponding substantially conical conical holding portion fitted and held on the conical inner peripheral surface on the downstream side of the road, and gradually expanded in the direction of the breaker plate from the upstream peripheral edge of the conical holding portion toward the center. An extruder comprising: a barrier bulging portion that protrudes; and a plurality of dispersion guide grooves formed in the outer peripheral surface of the barrier member over the entire length of the conical holding portion from the barrier bulging portion so as to be circumferentially separated from each other. Nozzle structure. 2. In the vicinity of the upstream peripheral edge of the conical holding portion, the peripheral edge of each of the dispersion guide grooves on the barrier bulging portion side becomes gradually wider with respect to the upstream peripheral direction of the conical holding portion. And the peripheral edge of each of the dispersion guide grooves on the side of the conical holding portion extending from the upstream peripheral edge in the direction of the outflow guide path is formed to be gradually narrower in the direction of the outflow guide path. The nozzle structure of an extruder according to claim 1, wherein: