KR101980254B1 - Apparatus for forming underground electric wire pipe - Google Patents

Abstract

The purpose of the present invention is to provide an apparatus for forming an underground electric wire pipe, which maximizes productivity by enabling a process of forming the underground electric wire pipe to be visually confirmed, uniformly maintaining wall thickness of a product (dimensional precision), and increasing cooling speed. The apparatus of the present invention includes: a driving shaft which is rotationally driven while being rotationally supported onto a support unit, and in which a cooling water flow path and a vacuum application path are provided; a cooling water/vacuum box which is installed while being fixed to an outer circumferential side of the driving shaft through a medium of a sealing member, and includes a cooling water distribution unit for supplying and discharging cooling water with respect to the cooling water flow path and a vacuum application unit for operating vacuum suction force with respect to the vacuum application path; a die head which is installed while being fixed to a forming proceeding direction side of the underground electric wire pipe along the driving shaft from the cooling water/vacuum box, and includes an air flow passage receiving a liquid resin from an extrusion device to flow out the resin in a forming proceeding direction of the underground electric wire pipe, and allowing air in the atmosphere to flow toward an inner side of the resin flown out in order to float the resin; a forming mold which is formed along structure of the underground electric wire pipe and coupled to a resin outflow side of the die head such that the forming mold is rotated together with the driving shaft, in which there is a vacuum rib having a negative vacuum pressure applied thereto through the vacuum application path so that the flown-out resin is formed into the underground electric wire pipe while the resin flown out from the die head is being adsorbed onto an outer circumferential surface of the forming mold, and which cools the inner surface portion of the resin formed into the underground electric wire pipe while a cooling process is performed by cooling water flowing through the cooling water flow path of the driving shaft; and a product cooling unit which cools an outer circumferential portion of the formed underground electric wire pipe.

Description

[0001] Apparatus for forming underground electric wire pipes [0002]

The present invention relates to an underground conduit forming apparatus, and more particularly, to an underground conduit forming apparatus that forms an underground conduit, which is embedded in the ground and safely protects transmission / distribution cables, to a uniform wall thickness, To an underground conduit forming apparatus.

The underground conduit is composed of a wave-like pipe made of the same material as the hard polyethylene resin used for safely protecting the transmission / distribution cable, etc., from earth pressure or foreign substances when buried in the ground. In addition, since the underground conduit is excellent in compressive strength or strength, flexibility and elasticity, it is used not only for protection of electric wires but also for various purposes such as various water / sewage pipes, sewage pipes and drain pipes.

The underground conduit is also called FEP pipe when it is made of insulating material such as fluorinated ethylene propylene. It is also known as CD conduit, PE conduit, ELP conduit depending on the material.

As a molding apparatus used for manufacturing such an underground conduit, there is an example disclosed in Patent Document 1 of the following prior art document. The underground conduit forming apparatus of Patent Document 1 has a configuration in which an inner surface having the same shape as the outer circumferential surface of the underground conduit is formed in the mold mold provided in the forming section and a vacuum line is formed on the inner circumferential surface side of the mold mold to form a vacuum . Accordingly, when the liquid resin, which is the material of the underground conduit, is injected into the inner peripheral surface of the mold mold and the vacuum between the mold mold and the resin is formed in vacuum, the injected resin flows in the state of being closely adhered to the inner surface of the mold mold The underground conduit is formed.

However, the following problems arise in the molding apparatus of Patent Document 1.

First, since the liquid resin is injected into the inner peripheral surface of the mold mold to form the underground conduit, it is impossible to visually confirm the shape of the underground conduit. Therefore, it is possible to detect at which point of the mold mold the failure occurs There is a difficult problem.

Secondly, since cooling is performed by water cooling only on the outer side of the mold mold and the outer peripheral side of the underground conduit, there is a problem that the cooling rate is slow and high productivity is difficult to achieve.

Third, there are bearings and sealing members (lead and waterproof packing) between the mold mold and the mold rotating member which rotates the mold mold. These bearings and the sealing member come into direct contact with the cooling water, Thereby causing a problem of increasing the dimensional tolerance and the raw material consumption.

Fourth, since the liquid resin injected into the mold mold along the inclined portion is adsorbed on the inner peripheral surface of the mold mold while being floated in the air, the dimension (thickness) of the molded underground conduit product to be molded becomes large, There is a problem that frequency is frequently increased.

Korean Patent Publication No. 10-2011-0030023 (Published March 23, 2011)

The present invention has been developed in order to overcome the problems of the conventional underground conduit forming apparatus as described above, and it is an object of the present invention to provide an underground conduit forming apparatus which can visually confirm the shape of a underground conduit and maintain uniform thickness (dimensional accuracy) And an object thereof is to provide an underground conduit forming apparatus which maximizes productivity by increasing a cooling rate.

In order to achieve the above object, the present invention provides an underground conduit forming apparatus comprising: a drive shaft rotatably supported on a support portion and rotationally driven, the drive shaft having a cooling water flow path and a vacuum operation path; A cooling water / vacuum box provided with a cooling water / vacuum part for supplying / discharging cooling water to / from the cooling water flow path and a vacuum operation part for applying a vacuum suction force to the vacuum operation path; The resin is supplied from a liquid resin from an extruding device and flows out toward the molding advancing direction of the underground conduit so that air in the atmosphere flows toward the inside of the outflow resin, A die head provided with an air flow path for allowing the air to flow along the structure of the underground conduit; A vacuum rib which is coupled to the resin outlet side of the attaching head so as to rotate together with the driving shaft and through which a vacuum negative pressure acts is formed so that the resin flowing out from the die head is adsorbed on the outer circumferential surface and formed into an underground conduit, A molding die for cooling the inner surface of the resin to be formed into the underground conduit while being cooled by the cooling water flowing through the flow path, and a product cooler for cooling the outer circumferential portion of the formed underground conduit.

In the present invention, the cooling water flow path of the drive shaft includes a first cooling water supply path for supplying the primary cooling water to the forming mold, a first cooling water discharge path for discharging the primary cooling water whose primary mold is cooled, A second cooling water supply passage for supplying the second cooling water to the mold, and a second cooling water discharge passage for discharging the second cooling water which is secondarily cooled to the molding mold. In addition, in the cooling water / vacuum box, the vacuum operation portion includes a vacuum suction chamber communicated with the vacuum operation path of the drive shaft, and the cooling water supply portion includes a cooling water supply portion and a cooling water discharge portion, And a water supply chamber communicated with the second cooling water supply passage, respectively, and the cooling water discharge portion may include a drain chamber communicated with the first cooling water discharge passage and the second cooling water discharge passage, respectively.

In the present invention, at the center of the drive shaft, a wire insertion hole for inserting a wire drawing wire into the formed underground conduit can be formed in an axial direction.

In the present invention, a first bearing and a second bearing are provided on a front end side and a rear end side of the die head to respectively hold the die head fixed when the drive shaft rotates, A second bearing adapter for receiving a second bearing is provided between the rear end side of the die head and the second bearing and a second bearing adapter for receiving the second bearing is provided between the rear bearing side of the die head and the first bearing adapter and the second bearing adapter, Air holes communicating with the air flow paths may be formed, respectively.

In the present invention, the first bearing adapter and the second bearing adapter may each have a groove portion to minimize heat transfer to the drive shaft due to contact with the leading and trailing edges of the die head.

In the present invention, the forming mold is provided with at least one cooling chamber for cooling by cooling water flowing through a cooling water channel of a drive shaft, and a vacuum operation path is formed in the vacuum rib so that a vacuum sound pressure acts through the vacuum operation path of the drive shaft. And a vacuum chamber communicating with the vacuum chamber.

According to the present invention, the forming mold has a helical tube structure along the shape of a ground conduit having a helical tube structure. The vacuum rib formed in the forming mold has a structure in which the first and second helical ribs Grooved vacuum ribs along the direction.

In the present invention, a circular vacuum rib may be additionally formed between each of the elongated vacuum ribs.

In the present invention, the forming mold may have a spiral tube structure along the shape of the underground conduit, and may have a structure in which the diameter gradually decreases along the molding progress direction of the underground conduit.

In the present invention, Teflon coating for reducing the coefficient of friction with resin may be formed on the outer circumferential surface of the forming mold.

In the present invention, the product cooling section may include an air cooling section that primarily cools the outer circumferential surface of the formed underground conduit, a water cooling section that performs secondary water cooling, and a cooling water removal section that removes the cooling water remaining on the outer circumferential surface of the underground conduit .

The underground conduit forming apparatus of the present invention having the above-described configuration has the following effects.

First, since the inner surface of the resin is cooled at the beginning and the end of the resin molding of the molding die and the outer circumferential surface of the underground conduit is cooled again by the product cooling part, the cooling rate of the underground conduit It is possible to achieve the effect of maximizing the productivity because the cooling efficiency and the cooling efficiency are much higher than those of the prior art, and the dimensional accuracy is also excellent.

Second, since the resin flowing out from the die head is formed into the underground conduit on the outer circumferential surface of the molding die, the worker can directly confirm the shape of the underground conduit formed in comparison with the conventional technique of molding on the inner circumferential surface of the mold, There is an effect that can be immediately detected.

Third, since the resin has a structure in which the resin is molded from the outer circumferential surface of the forming mold into the underground conduit, Teflon coating for reducing the coefficient of friction with the resin on the outer circumferential surface of the forming mold becomes possible, It is possible to achieve the effect of forming the underground conduit.

Fourth, by the air flow path structure provided inside the die head, the air flows in the air toward the inside of the resin flowing out from the die head toward the molding die side, so that the resin is lifted from the die head toward the beginning of the molding die It is possible to prevent the resin from sticking to the entrance portion of the molding die in a state where the resin is not cooled when the resin flows out.

Fifthly, according to the embodiment wherein the forming mold has a structure in which the diameter is decreased along the forming progress direction of the underground conduit, the coefficient of friction with the forming mold is reduced when the resin is molded into the underground conduit in the forming mold, Can be expected.

Sixth, in the spiral tube structure of the forming mold, a long groove type vacuum rib is formed along the direction of connecting the acid and the acid to the spiral groove in the first helical pitch, and a circular vacuum rib is additionally formed between the long groove type vacuum ribs, It is effective to make the dimension and shape of the underground conduit stable and constant.

1 is a front view showing an equipment for manufacturing an underground conduit including a molding apparatus according to the present invention.
2 is a plan view of Fig.
3 is a front view showing the overall configuration of an embodiment of a molding apparatus according to the present invention.
4 is a view for explaining cooling water and a vacuum and air supply structure in the present invention.
5 is a cross-sectional view of the drive shaft of Fig.
6 is a view showing a vacuum rib forming structure of a forming mold in the present invention.
Fig. 7 is a view showing a diameter gradient of a molding die in the present invention. Fig.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, it should be understood that the following embodiments are provided so that those skilled in the art can understand the present invention without departing from the scope and spirit of the present invention. It is not.

1 and 2 are respectively a front view and a plan view showing an apparatus for manufacturing an underground conduit including a molding apparatus according to the present invention. The apparatus includes an extrusion apparatus 100, a molding apparatus 200, and a drawer 300 have. Here, the underground conduit 400 to be formed and shaped has a spiral tube structure composed of mountains and valleys, as shown in the drawings.

The extrusion apparatus 100 sends liquid resin (synthetic resin), which is a molding material of the underground conduit 400 supplied through the hopper 110, to the molding apparatus 200 of the present invention at a constant pressure. The extrusion apparatus 100 and the molding apparatus 200 are connected by the resin transfer path 120 so that the liquid resin dispensed from the extrusion apparatus 100 passes through the resin transfer path 120 to the molding apparatus 200, .

The prime mover 300 draws the underground conduit 400, which has been formed in the molding apparatus 200, at a predetermined speed toward a bobbin or the like for product packaging.

The configuration of the extrusion apparatus 100 and the inserter 300 is a well-known technology that is outside the scope of the molding apparatus of the present invention, and thus a detailed description thereof will be omitted.

4 is a view for explaining the cooling water and the vacuum and air supply structure in the present invention, and Fig. 5 is a cross-sectional view of the molding apparatus according to the present invention, Sectional view of the drive shaft.

3, the main components constituting the molding apparatus 200 include a driving shaft 210, a cooling water / vacuum box 220, a die head 230, a molding mold 240, and a product cooling unit 250, Lt; / RTI >

The driving shaft 210 has a length extending from the outside of the cooling water / vacuum box 220 to the inside end of the forming mold 240 through the cooling water / vacuum box 220 and the die head 230. The driving shaft 210 is rotationally driven while being rotatably supported on a support portion 260 such as a work bed. That is, the drive shaft 210 is supported on the support portion 260 by a unit bearing (for example, a UCP bearing 261, 262) provided between the cooling water / vacuum box 220 and the die head 230, And is rotatably supported.

A drive gear portion 271 for rotating the drive shaft 210 is installed between the unit bearing 216 located at one end side of the drive shaft 210 and the cooling water / vacuum box 220. The driving unit 271 is connected to the driving motor 273 through a chain 272 so that the rotational driving force of the driving motor 273 is transmitted to the driving shaft 210 through the chain 272 and the driving unit 271 And the drive shaft 210 rotates.

4 and 5, the drive shaft 210 is provided with cooling water passages 211, 212, 213, and 214 and vacuum action paths 215 and 216. The cooling water flow paths 211, 212, 213 and 214 and the vacuum action paths 215 and 216 are elongated in the axial direction from the inside position of the cooling water / vacuum box 220 to the inside position of the forming mold 240, respectively.

In the present embodiment, the cooling water flow paths 211, 212, 213 and 214 are provided with a first cooling water supply path 211 for supplying the primary cooling water to the forming mold 240 and a second cooling water supply path 211 for discharging the primary cooling water, A second cooling water supply path 213 for supplying a second cooling water to the forming mold 240 and a second cooling water supplying unit 212 for discharging secondary cooling water that is secondarily cooled on the forming mold 240 And a second cooling water discharge path 214. And, the vacuum action paths 215 and 216 are illustrated by two lines.

At the center of the driving shaft 210, a wire insertion hole 217 for inserting a wire (not shown) for inserting a wire into the formed underground conduit 400 is formed in the axial direction. In the present invention, when forming the underground conduit (400), the ground wire (400) is inserted through the wire insertion hole (217) of the drive shaft (210) The wires for inserting wires are simultaneously inserted into the inside of the wire 400. Accordingly, it is not necessary to perform a separate operation of inserting the wires for inserting the wires into the underground conduit 400, and productivity and workability can be improved.

The cooling water / vacuum box 220 is located between the drive unit 271 and the die head 230. The cooling water / vacuum box 220 is installed on the support 260 on the outer circumferential side of the drive shaft 210 under the intermediary of the sealing member 210a, (Not shown). That is, the driving shaft 210 is rotated but the cooling water / vacuum box 220 is not rotated on the outer circumferential side of the driving shaft 210 and remains fixed.

The cooling water / vacuum box 220 has a cooling water supply part 221 for supplying and discharging cooling water to and from the cooling water flow paths 211, 212, 213 and 214 provided in the drive shaft 210 and a cooling water supply part 221 for applying cooling water to the vacuum action paths 215 and 216 And a vacuum acting portion 222, respectively.

The cooling water supply portion 221 includes a cooling water supply portion 221a and a cooling water discharge portion 221b. The cooling water supply unit 221a is provided with a water supply chamber 221aa that communicates with the first cooling water supply path 211 and the second cooling water supply path 213 of the drive shaft 210. In the water supply chamber 221aa, (221ab) is connected to receive cooling water from an external cooling water storage tank (not shown). The cooling water discharging portion 221b is provided with a drain chamber 221ba communicating with the first cooling water discharge passage 212 and the second cooling water discharge passage 214 of the drive shaft 210. The drain chamber 221ba A drain pipe 221bb is connected to discharge the used cooling water to the outside.

The vacuum acting portion 222 is provided with a vacuum suction chamber 222a communicating with the vacuum action paths 215 and 216 of the drive shaft 210. A vacuum suction pipe 222b is connected to the vacuum suction chamber 222a, And a vacuum sound pressure is supplied from a vacuum pump (not shown).

A sealing member 210a such as a retainer is installed around the water supply chamber 221aa, the drain chamber 221ba and the vacuum suction chamber 222a so as to prevent leakage and leakage of pressure to the drive shaft 210.

Next, the die head 230 is connected to the extrusion apparatus 100 by the resin transfer path 120 to supply liquid resin, which is a molding material of the underground conduit 400, from the extrusion apparatus 100, And flows out toward the forming conduction direction of the underground conduit (400) against the second conduit (240). As shown in FIG. 3, a spiral resin guide path 230a is formed in the die head 230, so that liquid resin can be uniformly fed toward the periphery of the forming mold 240.

The die head 230 is installed from the cooling water / vacuum box 220 along the drive shaft 210 in a state where it is fixed by the second bracket 275 on the support portion 260 on the molding progressing side of the underground conduit 400 . That is, when the drive shaft 210 is rotationally driven, the die head 230 does not rotate but remains fixed. A first bearing 231 and a second bearing 232 for supporting the die head 230 in a fixed state when the drive shaft 210 rotates are provided on the front end side and the rear end side of the die head 230, Respectively. A first bearing adapter 233 for receiving the first bearing 231 is provided between the tip end side of the die head 230 and the first bearing 231, A second bearing adapter 234 is provided between the bearings 232 to receive the second bearings 232.

As shown in FIG. 4, when the resin flows out from the die head 230 toward the entrance of the molding die 240, the resin is not cooled in the die head 230, An air flow passage 230b for allowing air in the air to flow toward the inside of the outflow resin to float the resin is provided so as to penetrate from the rear end portion to the front end portion of the die head 230 have. It is preferable that about six lines of the air flow path 230b are arranged at uniform intervals in the inner circumferential direction of the die head 230.

The first bearing adapter 233 and the second bearing adapter 234 communicate with the air flow path 230b so that air in the atmosphere flows into the air flow path 230b corresponding to the air flow path 230b. Air holes 233a and 234a are formed.

On the other hand, the temperature of the die head 230 is increased due to contact with the liquid resin at a high temperature. In this case, heat is transferred from the die head 230 to the drive shaft 210 to prevent the temperature of the drive shaft 210 from rising . To this end, the first bearing adapter 233 and the second bearing adapter 234 are formed with a space for minimizing the heat transfer to the drive shaft 210 due to the contact with the front end side and the rear end side of the die head 230, respectively Groove portions 233b and 234b are provided.

Next, the forming mold 240 is formed into a spiral tube structure according to the structure of the underground conduit 400 to be formed. The inside of the forming mold 240 is hollow so that the driving shaft 210 can be inserted therein. The bushings 241 and 242 are coupled to the front end and the rear end of the forming mold 240 and are closed from the outside. The molding die 240 is coupled to the resin outlet side of the die head 230 so as to rotate together with the drive shaft 210.

The molding die 240 is provided with one or more cooling chambers 243 and 244 which are cooled by cooling water flowing through the cooling water flow paths 211, 212, 213 and 214 of the driving shaft 210. In this embodiment, And a secondary cooling chamber 244 on the opposite side of the primary cooling chamber 243. The primary cooling chamber 243, the secondary cooling chamber 244 and the vacuum chamber 247 described below are formed by bushings 241 and 242 coupled to the front end and the rear end of the molding die 240, (248).

The primary cooling chamber 243 communicates with the first cooling water supply passage 211 of the drive shaft 210 and is connected to the cooling water supplied from the water supply chamber 221aa provided in the cooling water supply portion 221a of the cooling water / Is supplied to the primary cooling chamber 243 through the first cooling water supply path 211 so that the molding die 240 itself as well as the inner surface portion of the resin starting to be formed into the underground conduit 400 from the molding die 240 It is cooled first. The primary cooling chamber 243 is also in communication with the first cooling water discharge path 212 of the drive shaft 210 so that the cooling water that has primarily cooled the resin is passed from the primary cooling chamber 243 to the first cooling water discharge path 212 And discharged to the drain pipe 221bb through the drain chamber 221ba provided in the cooling water discharge section 221b of the cooling water / vacuum box 220 via the bypass pipe 221b.

The second cooling chamber 244 communicates with the second cooling water supply passage 213 of the drive shaft 210 so that the cooling water supplied through the water supply chamber 221aa of the cooling water supply portion 221a is supplied to the second cooling water supply passage 213 To the secondary cooling chamber 244 through the molding die 240 to cool the inner surface portion of the resin molded into the underground conduit 400 from the forming mold 240 with the molding die 240 itself. The secondary cooling chamber 244 is also in communication with the second cooling water discharge path 214 of the drive shaft 210 so that the cooling water that is secondarily cooled in the resin flows from the secondary cooling chamber 244 to the second cooling water discharge path 214 And then discharged to the drain pipe 221bb through the drain chamber 221ba provided in the cooling water discharge section 221b.

As described above, in the molding apparatus of the present invention, since the inner surface portion of the resin is first and secondly cooled at the beginning and the end of resin molding of the molding die 240, the cooling rate of the underground conduit 400, It is possible to maximize the productivity, and the dimensional accuracy is also excellent.

On the other hand, in the molding die 240, the resin flowing out from the die head 230 is adsorbed on the outer circumferential surface of the molding die 240, and the vacuum conduits 215 and 216 of the drive shaft 210 are formed into the underground conduit 400 A vacuum rib is formed through which vacuum negative pressure acts. In particular, as shown in FIG. 6, the vacuum ribs are formed in the spiral tube structure of the forming mold 240 along the direction of connecting the acid to the spiral in the first helical pitch, 245). Such an elongated groove type vacuum rib 245 serves to allow the resin to be diffused from the surface of the molding die 240 to the periphery so that the molding can be performed at a uniform thickness. It is sufficient that a total of six pairs of the long grooved vacuum ribs 245 are formed at regular intervals in the back and forth symmetry between the mountains and the mountains of the helical tube structure. A circular vacuum rib 246 may be additionally formed between the elongated vacuum ribs 245 when viewed along the helical direction of the forming mold 240. The circular vacuum ribs 246 may flow out of the die head 230 The resin is sucked toward the forming mold 240 so that the resin adheres well to the outer circumferential surface of the forming mold 240. The long groove type vacuum ribs 245 and the circular vacuum ribs 246 have the effect of stably and uniformly forming the dimension and shape of the underground conduit 400 to be formed.

Vacuum action paths 215 and 216 are formed in the molding die 240 so as to apply a vacuum negative pressure through the vacuum action paths 215 and 216 of the drive shaft 210 to the long groove type vacuum ribs 245 and the circular vacuum ribs 246 And a vacuum chamber 247 for communicating therewith. This vacuum chamber 247 is provided throughout the forming range of the vacuum ribs 245 and 246 in the forming mold 240.

7 is a view showing a diameter gradient of the forming mold according to the present invention. The forming mold 240 has a structure in which the diameter of the forming mold 240 is decreased along the forming progress direction of the underground conduit 400. That is, the acid portion forming the spiral structure of the molding die 240 from the initial portion to the end portion of the molding die 240 through which the resin is supplied from the die head 230 is 0.5 to 1 Deg. ≪ / RTI > This gradient reduces the coefficient of friction with the forming mold 240 when the resin is molded into the underground conduit 400 in the forming mold 240, thereby achieving an effect of achieving smooth molding.

Teflon coating may be formed on the outer circumferential surface of the forming mold 240 to reduce the coefficient of friction with the resin supplied to the forming mold 240. In the prior art as disclosed in Patent Document 1 in which the liquid conduit is injected into the inner circumferential surface of the mold mold to form the underground conduit, it is impossible at all to structurally perform a coating operation for reducing the friction coefficient on the 'inner circumferential surface' of the mold mold . However, in the present invention, the resin is formed into the underground conduit 400 at the 'outer circumferential surface' exposed to the outside of the forming mold 240, so that the Teflon coating operation for reducing the friction coefficient becomes possible, It is possible to smoothly form the underground conduit 400 without pressing on the outer circumferential surface of the underground conduit 240.

The product cooling unit 250 cools the outer circumferential portion of the underground conduit 400 formed in the forming mold 240. The air cooling unit 251 and the water cooling unit 252, 253). As shown in FIG. 3, the air cooling unit 251 is installed so as to surround the outer periphery of the molding die 240. When the resin is formed into the underground conduit 400 in the molding die 240, So that air is firstly cooled. The water cooling section 252 is provided at the next position of the air cooling section 251 and performs secondary water cooling by injecting cooling water onto the outer circumferential surface of the underground conduit 400 passing through the air cooling section 251 do. The cooling water removing unit 253 is installed at the next position of the water cooling unit 252 and injects air toward the outer circumferential surface of the water-cooled underground conduit 400 cooled by the cooling water of the water cooling unit 252, 400 to the outside.

As described above, in the present invention, the inner surface portion of the resin is divided into primary and secondary portions by the primary cooling chamber 243 and the secondary cooling chamber 244 at the beginning and the end of resin molding of the forming mold 240 The air cooling unit 251 and the water cooling unit 252 of the product cooling unit 250 cool the outer circumferential surface of the underground conduit 400 after the molding is completed over the first and second stages, The cooling rate and the cooling efficiency are greatly improved.

Next, a process of forming the underground conduit 400 in the underground conduit forming apparatus of the present invention constructed as described above will be described.

The drive shaft 210 of the molding apparatus 200 is rotatably supported on the support portion 260 by the unit bearings 261 and 262 so that the rotational drive force of the drive motor 273 is transmitted to the chain 272 and the drive unit 271 And is rotationally driven in one direction. The liquid resin as a molding material of the underground conduit 400 is supplied to the extrusion apparatus 100 through the hopper 110 and then supplied from the extrusion apparatus 100 through the resin transfer path 120 to the molding apparatus 200. [ And is discharged under a constant pressure to the die head 230 of FIG.

The resin supplied to the die head 230 is uniformly dispersed and flows toward the outer peripheral surface of the forming mold 240 while flowing along the resin guide path 230a inside the die head 230. [

Vacuum sound pressure is applied to the vacuum suction chamber 222a through the vacuum suction pipe 222b at the vacuum operation part 222 of the cooling water / vacuum box 220. Vacuum sound pressure is applied to the vacuum operation paths 215 and 216 of the drive shaft 210 Through the elongated vacuum ribs 245 and the circular vacuum ribs 246 of the forming mold 240. The vacuum suction ribs 246 and 246 are formed in the same manner as described above. The resin flowing from the die head 230 to the outer circumferential surface of the forming mold 240 is formed into the underground conduit 400 while being adsorbed to the outer circumferential surface of the forming mold 240 at the beginning of the forming mold 240. In particular, the circular vacuum ribs 246 attract resin leaking from the die head 230 toward the molding die 240 so that the resin adheres well to the outer peripheral surface of the molding die 240, and the elongated vacuum ribs 245, The resin is diffused from the surface of the molding die 240 to the periphery so that the molding can be performed with a uniform thickness. Air in the air flows into the die head 230 through the air flow path 230b and the air holes 233a and 234a provided in the first and second bearing adapters 233 and 234, The resin that flows out from the die head 230 toward the entrance of the molding die 240 adheres to the entrance of the molding die 240 in a state in which the resin flows out from the die head 230 in an uncooled state .

In the cooling water supply portion 221 of the cooling water / vacuum box 220, the cooling water is supplied to the water supply chamber 221aa of the cooling water supply portion 221a from the external cooling water storage tank through the water supply pipe 221ab. At this time, since the cooling water / vacuum box 220 is installed on the outer circumference side of the driving shaft 210 without being rotated under the intermediation of the sealing member 210a, the cooling water / vacuum box 220 is installed on the driving shaft 210 when the driving shaft 210 rotates. And the cooling water in the water supply chamber 221aa flows into the first cooling water supply path 211 and the second cooling water supply path 213, respectively. The cooling water is supplied to the primary cooling chamber 243 and the secondary cooling chamber 244 of the molding die 240, respectively. The cooling water supplied to the primary cooling chamber 243 primarily cools the inner surface portion of the resin that starts to be formed into the underground conduit 400 from the forming mold 240 as well as the forming mold 240. The used cooling water, which is the primary cooling of the inner surface of the resin, passes through the first cooling water discharge passage 212 of the drive shaft 210 and is discharged to the drainage chamber 221ba provided in the cooling water discharge portion 221b of the cooling water / vacuum box 220, And then discharged to the drain pipe 221bb. The cooling water supplied to the secondary cooling chamber 244 cools the inner surface portion of the resin molded by the underground conduit 400 in the molding die 240 with the molding die 240 itself. The used cooling water that has been cooled secondarily from the inner surface of the resin is discharged to the water discharge pipe 221bb through the water discharge chamber 221ba provided in the cooling water discharge portion 221b via the second cooling water discharge path 214 of the drive shaft 210 . Since the inner surface of the resin is cooled first and secondarily at the beginning and the end of resin molding of the forming mold 240, the cooling speed of the underground conduit 400 to be formed is much faster than that of the prior art, , And the dimensional accuracy is also excellent.

Meanwhile, when the underground conduit 400 is formed, wires for drawing wires are simultaneously inserted into the underground conduit 400 via the wire insertion holes 217 of the drive shaft 210, There is no need to perform a separate operation of inserting the wire for the wire, thereby greatly improving the productivity and workability.

Since the molding die 240 has a structure in which the diameter of the forming mold 240 gradually decreases along the forming progress direction of the underground conduit 400, when the resin is molded into the underground conduit 400 in the molding die 240, The coefficient of friction with the mold 240 is reduced and smooth molding is performed. Since the Teflon coating for reducing the coefficient of friction with the resin supplied to the forming mold 240 is formed on the outer circumferential surface of the forming mold 240, the resin can be smoothly adhered to the outer circumferential surface of the forming mold 240, It is possible to perform the molding of the mold 400. That is, in the prior art, it is impossible to perform a coating operation for reducing the friction coefficient on the 'inner circumferential surface' of the mold mold because the liquid resin is injected into the 'inner circumferential surface' of the mold mold to form the underground conduit. In the present invention, the resin is formed into the underground conduit 400 at the 'outer circumferential surface' exposed to the outside of the forming mold 240, so that the Teflon coating operation for reducing the friction coefficient becomes possible.

After the resin is formed into the underground conduit 400 in the forming mold 240, the outer circumferential portion of the underground conduit 400 is cooled in the product cooling portion 250. The air cooling unit 251 surrounding the outer periphery of the molding die 240 first blows air to the outer circumferential surface of the molding die 240 as soon as the resin is molded into the underground conduit 400, . Subsequently, the underground conduit 400 having passed through the air cooling section 251 is cooled again by the water cooling section 252 provided at the next position of the air cooling section 251. The water cooling section 252 ) Injects cooling water onto the outer circumferential surface of the underground conduit (400) to perform water cooling in the second order. Cooling water remains on the outer circumferential surface of the underground conduit 400 that is water-cooled by the water cooling unit 252. By the air injected from the cooling water removing unit 253 installed at the next position of the water cooling unit 252, Residual cooling water is removed. The inner surface of the resin molded into the underground conduit 400 by the primary cooling chamber 243 and the secondary cooling chamber 244 at the beginning and the end of the resin molding of the forming mold 240 has a primary And the outer circumferential surface of the underground conduit 400 that has been formed is cooled by the air cooling unit 251 and the water cooling unit 252 of the product cooling unit 250 in the primary and secondary The cooling rate and the cooling efficiency are greatly improved.

Finally, the underground conduit 400, which has been formed and cooled as described above, is taken by the drawer 300 and packed in a predetermined unit such as a bobbin.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, This is possible.

100: extrusion apparatus 110: hopper
120: resin transfer path 200: molding apparatus
210: drive shaft 210a: sealing member
211: first cooling water supply path 212: first cooling water discharge path
213: second cooling water supply path 214: second cooling water discharge path
215, 216: Vacuum operation 217: Wire insertion hole
220: cooling water / vacuum box 221: cooling water supply /
221a: Cooling water supply part 221aa: Water supply room
221ab: water pipe 221b: cooling water discharge part
221ba: drainage chamber 221bb: drainage pipe
222: Vacuum acting portion 222a: Vacuum suction chamber
222b: vacuum suction pipe 230: die head
230a: resin induction furnace 230b: air flow path
231: first bearing 232: second bearing
233: first bearing adapter 233a, 234a: air hole
233b, 234b: groove portion 234: second bearing adapter
240: Molding mold 241, 242: Bushing
243: primary cooling chamber 244: secondary cooling chamber
245: Long groove type vacuum ribs 246: Circular vacuum ribs
247: vacuum chamber 248: sealing member
250: product cooling section 251: air cooling section
252: Water cooling section 253: Cooling water removal section
260: Support portion 261, 262: Unit bearing
271: driver unit 272: chain
273: drive motor 274: first bracket
275: second bracket 300:
400: Underground conduit

Claims (11)

A drive shaft rotatably supported on the support portion and rotationally driven, the drive shaft having a cooling water flow path and a vacuum operation path;
A cooling water supply portion provided in a state of being fixed to the outer circumferential side of the drive shaft under the intermediation of a sealing member and provided with a cooling water supply portion for supplying and discharging cooling water to and from the cooling water flow path and a vacuum operation portion for applying a vacuum suction force to the vacuum operation path / Vacuum box;
A liquid resin is supplied from an extruding device and flows out in a molding progress direction of the underground conduit, and air in the atmosphere flows out from the coolant / vacuum box in the outflow direction of the underground conduit, A die head having an air flow path for causing the resin to float toward the inside of the resin to be floated;
A plurality of vacuum tubes, which are formed along the structure of the underground conduit and are coupled to the resin outlet side of the die head so as to rotate together with the drive shaft, the resin flowing out from the die head being adsorbed on the outer circumferential surface, And the cooling rib is formed through the cooling water flowing through the cooling water flow path of the driving shaft to cool the inner surface of the resin to be formed into the underground conduit while being cooled by the cooling water flowing through the cooling water flow path of the driving shaft, A molding die having at least one cooling chamber for cooling by cooling water and having a vacuum chamber communicating the vacuum operation path with the vacuum rib so that a vacuum negative pressure acts through the vacuum operation path of the drive shaft;
And a product cooler for cooling the outer circumferential surface of the formed underground conduit.
The method according to claim 1,
Wherein the cooling water flow path of the drive shaft includes a first cooling water supply path for supplying the primary cooling water to the forming mold, a first cooling water discharge path for discharging the primary cooling water that has primarily cooled the forming mold, A second cooling water supply passage for supplying a second cooling water to the mold, and a second cooling water discharge passage for discharging secondary cooling water which is secondarily cooled to the molding mold,
In the cooling water / vacuum box, the vacuum operation portion includes a vacuum suction chamber communicating with a vacuum operation path of the drive shaft,
In the cooling water / vacuum box, the cooling water supplying and discharging unit includes a cooling water supply unit and a cooling water discharge unit, and the cooling water supply unit includes a water supply chamber communicating with the first cooling water supply path and the second cooling water supply path, And the discharge portion includes a drain chamber communicated with the first cooling water discharge path and the second cooling water discharge path, respectively.
The method according to claim 1,
Wherein a wire insertion hole for inserting an electric wire drawing wire into the formed underground electric wire tube is formed in the center of the drive shaft so as to penetrate in the axial direction.
The method according to claim 1,
Wherein a first bearing and a second bearing are provided on a leading end side and a trailing end side of the die head to respectively hold the die head in a fixed state when the drive shaft rotates and between the leading end side of the die head and the first bearing A second bearing adapter for receiving a second bearing is provided between a rear end side of the die head and the second bearing,
Wherein the first bearing adapter and the second bearing adapter each have an air hole communicating with the air flow path.
5. The method of claim 4,
Wherein the first bearing adapter and the second bearing adapter are each formed with a groove portion for minimizing heat transfer to the drive shaft due to contact with the leading end side and the rear end side of the die head.
delete The method according to claim 1,
Wherein the forming mold has a spiral tube structure along the shape of the underground conduit having a helical tube structure, wherein the vacuum ribs formed in the molding mold are arranged in a first helical pitch along a direction Wherein the groove is formed as a long groove-like vacuum rib.
8. The method of claim 7,
And a circular vacuum rib is additionally formed between each of the elongated vacuum ribs.
The method according to claim 1,
Wherein the forming mold has a helical tube structure along the shape of the underground conduit, and the diameter of the underground conduit is reduced along the forming progress direction of the underground conduit.
The method according to claim 1,
Wherein a Teflon coating for reducing a coefficient of friction with the resin is formed on an outer circumferential surface of the molding die.
The method according to claim 1,
The product cooling unit includes an air cooling unit that primarily cools the outer circumferential surface of the formed underground conduit tube, a water cooling unit that performs secondary water cooling, and a cooling water removing unit that removes cooling water remaining on the outer circumferential surface of the underground conduit Wherein the underground conduit forming device is a ground conduit forming device.

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