JP2023017495A - Pipe body manufacturing device - Google Patents

Abstract

To provide a pipe body manufacturing device that enables stable molding by preventing molding defects due to drawdown by quickly attaching a resin extruded from a resin discharge port to an inner wall of a mold block.SOLUTION: A pipe body manufacturing device includes: a resin discharge part (resin outlet 47) that discharges a cylindrical molten resin into mold blocks 36, 38; a shape adjusting part (shape adjusting attachment 50) that expands a diameter of the cylindrical molten resin discharged from the resin discharge part; and a pressure-retaining part (pressure-retaining jig 60) that can retain an internal pressure of the cylindrical molten resin discharged from the resin discharge part.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD The present invention relates to a manufacturing apparatus for tubular bodies such as resin liners for high-pressure tanks (also called pressure vessels), and more particularly to a manufacturing apparatus for forming tubular bodies by extrusion corrugated tube molding.

As a method for manufacturing this type of tubular body, for example, in Patent Document 1, a plurality of mold blocks connected like a belt surround a mandrel, and a cavity space is formed between the mold blocks and the mandrel. A method is described in which a resin material is extruded into the mold and mold blocks are sequentially fed out to form a tubular body (synthetic resin pipe).

In addition, in Patent Document 2, a corrugated protective layer having peaks and valleys on the outer peripheral surface is supplied to the extrusion molding part, and in the extrusion molding part, the protective layer is applied to the molten resin that constitutes the outer cover. A method is described for spreading a tubular protective layer in contact and extruding a jacket.

JP-A-5-318556 JP 2020-140064 A

In such extrusion corrugated tube molding, the cylindrical molten resin extruded from the resin discharge port (hereinafter sometimes referred to as a molten resin tube) hangs down under the influence of gravity (also referred to as drawdown). . In particular, when the diameter expansion ratio is about several times, the distance between the molten resin tube extruded from the resin discharge port and the mold block becomes long, and the upper portion of the molten resin tube is less likely to come into contact with the mold (difficult to stick). It is difficult to shape according to the mold. That is, if the diameter of the molded product is increased, the molded product may sag due to gravity before it hardens, resulting in poor molding.

In view of the above circumstances, the present invention is to manufacture a tubular body that enables stable molding by preventing molding defects due to drawdown by quickly sticking the resin extruded from the resin discharge port to the inner wall of the mold block. The purpose is to provide an apparatus.

In order to achieve the above object, the tubular body manufacturing apparatus of the present invention is a tubular body manufacturing apparatus molded into a cylindrical or tubular shape, comprising a mold block and a tubular molten resin discharged into the mold block. a resin discharge portion that can change the relative position in the axial direction with respect to the mold block; a shape adjustment portion that enlarges the diameter of the cylindrical molten resin discharged from the resin discharge portion; and a pressure retaining portion capable of retaining the internal pressure of the tubular molten resin discharged from the discharge portion.

In a preferred aspect, the shape adjusting section includes a gas discharge path for discharging gas in a direction inclined radially outward from inside the cylindrical molten resin discharged from the resin discharge section. .

In another preferred aspect, the gas discharge passage includes a central supply passage extending in the axial direction, and a cylindrical resin discharge portion branching from the central supply passage in a direction inclined radially outward and discharged from the resin discharge portion. and a plurality of inclined supply paths opening into the molten resin.

In another preferable aspect, the shape adjusting portion includes a guide surface that guides the cylindrical molten resin discharged from the resin discharging portion radially outward as it goes downstream.

In another preferable aspect, the shape adjustment portion is provided at the discharge side end portion of the resin discharge portion.

In another preferred aspect, the pressure holding portion is configured by a pressure holding jig extending along the axial direction within the mold block.

In another preferred aspect, the holding pressure portion is connected to and held by the shape adjusting portion.

In another preferred aspect, the shape adjusting section includes a gas discharge path for discharging gas in a direction inclined radially outward from the cylindrical molten resin discharged from the resin discharge section. , the holding pressure portion extends along the axial direction in the mold block and through the inner side of the small diameter portion having the smallest diameter of the tubular resin pressed against the mold block by the pressure of the gas. It consists of jigs.

In another preferred aspect, a clearance area between the small diameter portion and the pressure holding jig passing inside the small diameter portion is equal to or less than the minimum flow passage cross-sectional area of the gas discharge path.

According to the present invention, when forming a tubular body by extruded corrugated tube molding, the pressure holding section applies internal pressure to the cylindrical molten resin while shaping it, so that the resin extruded from the resin discharge section is quickly molded. By sticking it to the inner wall of the block, it is possible to prevent molding defects due to drawdown and achieve stable molding.

It is a perspective view which shows typically the manufacturing apparatus of the liner (tubular body) which concerns on this embodiment. It is a longitudinal cross-sectional view showing a liner (tubular body) manufacturing apparatus according to the present embodiment. 1 is a longitudinal sectional view showing an enlarged main part of a liner (tubular body) manufacturing apparatus according to an embodiment; FIG. It is a side view of a shape adjustment attachment. FIG. 5 is a cross-sectional view taken along the line AA of FIG. 4;

Embodiments of the present invention will be described below with reference to the drawings.

First, a high-pressure tank resin liner (hereinafter simply referred to as a liner) 10 to be manufactured in the present embodiment will be described, and then a manufacturing apparatus 30 for the liner 10 will be described. After that, a method for manufacturing the liner 10 will be described. 1 to 5 indicate the central axis of the liner 10. As shown in FIG. Further, when simply described as an axial direction, it indicates a direction along the central axis CL, and when described as a radial direction, it indicates a direction along the radial direction of the liner 10 .

(Construction of liner)
1 and 2 show cross-sectional views of liner 10 during molding. Since the finished liner 10 has basically the same configuration, the configuration of the liner 10 will be described with reference to these figures.

The liner 10 is configured as a tubular body having an overall cylindrical or annular shape. The liner 10 includes a substantially cylindrical body portion 12 and domes formed at both ends in the axial direction of the body portion 12 and gradually narrowed (reduced in diameter) toward the side opposite to the body portion 12 (outward in the axial direction). and a substantially cylindrical neck portion 16 formed at the axial end of the dome portion 14 opposite to the body portion 12 and having a smaller diameter than the body portion 12 . In the present embodiment, the neck portion 16 is the smallest diameter portion of the liner 10 .

The liner 10 is, for example, a container body of a high-pressure tank used as a hydrogen tank mounted on a fuel cell vehicle, and constitutes the innermost layer of the high-pressure tank. The liner 10 is made of a resin material (nylon, polyethylene, etc.), and a reinforcing layer (for example, a fiber-reinforced resin layer) (not shown) is formed on the outer peripheral surface of the liner 10 to form a high-pressure tank.

The neck portion 16 of the liner 10 has an open end (not shown) in the axial direction opposite to the dome portion 14, and is configured to fit a plug (not shown) from this open end. . A seal ring (not shown) forming a part of the plug is brought into close contact with the inner surface 16A of the neck portion 16 to seal the high-pressure tank.

(Configuration of liner manufacturing equipment)
Next, a manufacturing apparatus 30 for the liner 10 of this embodiment will be described with reference to FIGS. 1 to 5. FIG.

FIG. 1 schematically shows the overall configuration of a manufacturing apparatus 30 for the liner 10 according to this embodiment. As shown in this figure, the liner 10 manufacturing apparatus 30 includes a first outer mold section 32 and a second outer mold section 34 . In this figure, the lower halves of the first outer mold portion 32 and the second outer mold portion 34 cut in the horizontal direction are shown. , and the pressure holding jig 60 are shown in an uncut state. The first outer mold part 32 is a caterpillar-shaped mold that is connected to a plurality of mold blocks 36 and circulates in the first direction R1 at a constant speed. Similarly, the second outer mold portion 34 is a caterpillar-like structure that is connected to a plurality of mold blocks 38 and circulates in a second direction R2 opposite to the first direction R1 at the same speed as the first outer mold portion 32. is the mold.

A plurality of mold blocks 36 and a plurality of mold blocks 38 abut against each other in a linear travel region P in which a part of the respective travel paths of the first and second outer mold portions 32 and 34 are straight. It is configured to move linearly in the same direction in a contact state, that is, in a state in which the mold is closed. That is, the first outer mold portion 32 and the second outer mold portion 34 merge at the starting end of the straight running region P on the upstream side in the running direction (hereinafter referred to as the “starting end”), and the downstream side of the straight running region P in the running direction The first outer mold portion 32 and the second outer mold portion 34 diverge at the terminal end (hereinafter referred to as "terminal end" as appropriate). Note that FIG. 1 schematically shows the overall configuration of the manufacturing apparatus 30 and does not show details of the individual shapes of the plurality of mold blocks 36 and the plurality of mold blocks 38. Therefore, the plurality of mold blocks 36 and the plurality of mold blocks 38 The construction of the mold block 38 will be described below with reference to FIG.

The plurality of mold blocks 36 of the first mold section 32 and the plurality of mold blocks 38 of the second mold section 34 are configured to mold the liner 10 from the outside, as shown in FIG. 2 shows the side of the plurality of mold blocks 36 forming the first outer mold section 32, the plurality of mold blocks 38 forming the second outer mold section 34 are also shown on the first outer mold block 36 side. It is the same as the plurality of mold blocks 36 that constitute the mold portion 32 . Specifically, the plurality of mold blocks 36 (38) are provided with cavities having a substantially semicircular cross-section, and a body portion molding portion 22 for molding the body portion 12 of the liner 10 and a dome portion for molding the dome portion 14. It includes a part molding portion 24 and a neck molding portion 26 for molding the neck portion 16 . The trunk molding portion 22 is formed of a relatively large-diameter semi-cylindrical surface that is elongated in the axial direction. The dome molding portion 24 is formed at the axial end of the body molding portion 22 and is formed of a tapered surface whose diameter gradually decreases toward the side opposite to the body molding portion 22 . The neck molding portion 26 is formed at the axial end of the dome molding portion 24 and is composed of a semi-cylindrical surface with a relatively small diameter (smaller diameter than the body molding portion 22). In this embodiment, the neck molding portion 26 is a small diameter portion with the smallest inner diameter. The body molding portion 22, the dome molding portion 24, and the neck molding portion 26 constitute molding surfaces (inner surfaces) of the plurality of mold blocks 36 and 38. As shown in FIG.

Since the linear running region P is a region where molding is performed, as shown in FIG. 38 run in contact with each other.

The size and shape of the plurality of mold blocks 36, 38 are not limited to the example shown in FIG. For example, the dome portion 14 and the neck portion 16 may be composed of only one mold block 36, 38 (in other words, the boundary between the body portion 12 and the dome portion 14 and the boundary between the dome portion 14 and the neck portion 16 may be formed in a plurality of blocks). or the dome portion 14 or neck portion 16 may span two or more of the mold blocks 36,38.

Further, the plurality of mold blocks 36 of the first outer mold portion 32 and the plurality of mold blocks 38 of the second outer mold portion 34 suck molten resin tubes 48, which will be described later, onto the inner surfaces (molding surfaces) thereof. A suction opening (not shown) is opened for pattern transfer.

Returning to FIG. 1, in the region on the upstream side of the linear travel region P, a nozzle 40 is provided as a resin discharge device that constitutes a part of the extruder. The nozzle 40 includes a substantially cylindrical outer die 44 and a substantially cylindrical inner die 42 (see FIGS. 2 and 3) which has a smaller diameter than the outer die 44 and is arranged inside (hollow portion) of the outer die 44. and

As shown in FIGS. 2 and 3, the outer die 44 and the inner die 42 are arranged concentrically with their leading ends (downstream ends) substantially aligned, and the longitudinal direction of the first outer die portion is in the linear travel region P. 32 and the running direction of the second outer mold part 34 . A (substantially cylindrical) gap between the outer die 44 and the inner die 42 constitutes a resin supply path 46 through which molten resin heated and melted in a resin supply device (not shown) passes. 44 (downstream end in the direction of resin supply) and the end of the inner die 42 (downstream end in the direction of resin supply) forms a (substantially annular) opening, which is a resin discharge port (resin discharge portion). 47. The molten resin heated and melted in a resin supply device (not shown) passes through the gap between the outer die 44 and the inner die 42 (that is, the resin supply path 46) and is discharged from the resin discharge port 47 into a substantially cylindrical shape. It is continuously extruded at a constant speed as a shaped molten resin tube 48 . At this time, the molten resin tube 48 is a substantially cylindrical resin in a non-solidified state, and its extrusion direction S is the running direction of the first outer mold portion 32 and the second outer mold portion 34 in the straight running region P. is approximately the same as Furthermore, the inside (hollow portion) of the inner die 42 is provided with a gas supply path 49 (specifically, upstream thereof) through which gas (nitrogen gas as an example) (also referred to as blow air) supplied from a gas pressure applying device (not shown) passes. part).

A shape adjusting attachment (hereinafter simply referred to as an attachment) 50 as a shape adjusting section is attached to the tip (downstream end or discharge side end) of the inner die 42 of the nozzle 40 .

The attachment 50 is formed in a stepped columnar shape, and its outer peripheral surface 52 is arranged so that the molten resin tube 48 extruded (discharged) from the resin discharge port 47 is radially outward (in other words, the inner surfaces of the mold blocks 36 and 38). ) to expand the diameter of the molten resin tube 48 .

4 and 5 together with FIGS. 2 and 3, the outer peripheral surface (guide surface) 52 of the attachment 50 is formed of a substantially cylindrical surface having substantially the same outer diameter as the inner die 42. 42, and a starting surface portion 52A extending axially continuously from the outer peripheral surface of the die 42, and a starting surface portion 52A formed at the axial end portion of the starting surface portion 52A and gradually expanding toward the side opposite to the inner die 42 (downstream side in the resin supply direction). An intermediate widened portion 52B composed of a tapered surface or a truncated conical surface (which increases in diameter), and an approximate diameter larger than that of the inner die 42 formed at the axial end portion of the intermediate widened portion 52B on the side opposite to the inner die 42. and a terminal surface portion 52C formed of a cylindrical surface.

Therefore, the molten resin tube 48 extruded (discharged) from the resin discharge port 47 in the extrusion direction S passes through the starting end face portion 52A continuous with the resin discharge port 47 (resin supply path 46) in the extrusion direction S, As it goes downstream, it is guided radially outward by the widened portion 52B (in other words, in a direction inclined outward with respect to the extrusion direction S), and its diameter increases (see FIG. 3). See solid arrows in mold blocks 36, 38).

Further, as shown in FIGS. 2 to 5, the gas supplied through the inner die 42 inside the attachment 50 is discharged (introduced) into the molten resin tube 48, and the diameter of the molten resin tube 48 is increased. (to the inner surfaces of mold blocks 36, 38) are formed. The gas discharge path 54 constitutes, together with the inside (hollow portion) of the inner die 42, a gas supply path 49 through which gas supplied from a gas pressure application device (not shown) passes. In other words, the gas discharge path 54 constitutes the downstream portion of the gas supply path 49 .

The gas discharge path 54 described above includes a relatively large-diameter central supply path 54A extending axially (linearly) from the end on the inner die 42 side (the upstream end in the gas supply direction), and a central supply path 54A. A plurality of relatively small-diameter inclined supply paths branching from the axial end (downstream end in the gas supply direction) of 54A opposite to the inner die 42 and extending in a direction inclined radially outward. 54B and . In this embodiment, four inclined supply paths 54B are arranged at intervals of 90 degrees around the central supply path 54A (in the circumferential direction). The tip of the inclined supply path 54B (the end opposite to the inner die 42 (the downstream end in the direction of gas supply)) is the terminal surface portion 52C of the outer peripheral surface (guide surface) 52 of the attachment 50 described above (in the illustrated example, , near its downstream end), and the openings at the tip (in this embodiment, four openings in total in the circumferential direction) serve as gas supply ports 55 .

Therefore, the gas supplied through the inside of the inner die 42 passes through the gas discharge path 54 (the central supply path 54A, the inclined supply path 54B) from the gas supply port 55 in a direction inclined radially outward (in other words, Then, the molten resin is discharged into the inside of the molten resin tube 48 guided by the outer peripheral surface (guide surface) 52 of the attachment 50 in a direction inclined outward with respect to the extrusion direction S, and the diameter of the molten resin tube 48 is expanded. (see dashed arrows in mold blocks 36 and 38 in FIG. 3).

Note that the inclined supply path 54B only needs to extend in a direction that is inclined radially outward. (In other words, the inclination angle of the inclined supply path 54B and the inclination angle of the intermediate widened portion 52B may be substantially the same), or they may be formed at different angles.

Further, the position, shape, size, etc. of the outer peripheral surface 52 of the attachment 50 and the gas discharge path 54 are of course not limited to the illustrated example.

At the center of the axial end portion of the attachment 50 on the inner die 42 side, a small-diameter fastening portion 51 having a male screw 51A formed on its outer periphery is formed (protruded axially). The attachment 50 is attached and fixed to the tip of the inner die 42 of the nozzle 40 by screwing the male thread 51A of the fastening portion 51 into the female thread 41A of the receiving portion 41 provided on the inner periphery of the inner die 42. there is It should be noted that the attachment structure of the attachment 50 to the nozzle 40 is not limited to the illustrated example.

At the center of the axial end of the attachment 50 opposite to the inner die 42, a stepped small-diameter fastening portion 59 having a male screw 59A formed on the outer periphery is formed (protruded axially). . A female screw 69A of a receiving portion 69 provided on the inner circumference of the pressure holding jig 60, which will be described later in detail, is screwed into the male screw 59A of the fastening portion 59, thereby turning the tip (downstream end) of the attachment 50. ), a pressure holding jig 60 as a pressure holding portion is attached and fixed.

The pressure holding jig 60 attached to the tip of the attachment 50 has a substantially cylindrical shape extending in the axial direction (linearly), and is positioned inside the molten resin tube 48 extruded (discharged) from the resin discharge port 47 . The internal pressure of the molten resin tube 48 extruded (discharged) from the resin discharge port 47 is maintained (held) in the plurality of mold blocks 36 and 38, more specifically, in the plurality of mold blocks 36 and 38. do.

The axial length of the pressure holding jig 60 can be inserted into the necks 16 (in other words, the two neck moldings 26 of the plurality of mold blocks 36 and 38) formed at both axial ends of the liner 10 during molding. length. In other words, the axial length of the pressure holding jig 60 is set to be equal to or greater than the axial length (interval) between the neck portions (thin diameter portions) 16 formed at both axial ends of the liner 10 during molding. ing. In addition, the outer diameter of the pressure holding jig 60 is equal to that of the necks 16 formed at both axial ends of the liner 10 during molding (in other words, the melt pressure pressed against the two neck moldings 26 of the plurality of mold blocks 36 and 38). It is formed to have a diameter equal to or slightly smaller than the inner diameter of the resin tube 48).

Therefore, the pressure retaining jig 60 is inserted through the necks 16 formed at both axial ends of the liner 10 during molding, and the opening (area) of the neck 16 is narrowed by the cross-sectional area of the pressure retaining jig 60 ( Decrease). Therefore, the flow resistance at the neck portion 16, which is a small-diameter portion, increases, and the gas is discharged from the gas supply port 55 into the molten resin tube 48 through the gas discharge path 54 (central supply path 54A, inclined supply path 54B). However, it becomes difficult to escape from the neck portion 16 of the liner 10 in the middle of molding, stays in the molten resin tube 48 in the middle of molding, and makes it easier to keep the internal pressure of the molten resin tube 48 .

In this embodiment, the pressure holding jig 60 and the neck portion 16 of the liner 10 in the middle of molding (in other words, the molten resin tube 48 pressed against the two neck molding portions 26 of the plurality of mold blocks 36 and 38) (circular The annular clearance area is set equal to or smaller than the minimum channel cross-sectional area (minimum value of the channel cross-sectional area) of the gas discharge path 54 formed in the attachment 50 described above. This creates an annular shape between the pressure holding jig 60 and the neck portion 16 of the liner 10 during molding (in other words, the molten resin tube 48 pressed against the two neck molding portions 26 of the plurality of mold blocks 36 and 38). ) The amount of gas that escapes (is discharged) from the clearance is more reliably than the amount of gas that is discharged (supplied) from the gas supply port 55 through the gas discharge path 54 (central supply path 54A, inclined supply path 54B). less. In other words, the amount of gas discharged from the inside of the molten resin tube 48 is surely smaller than the amount of gas supplied to the inside of the molten resin tube 48 . Therefore, the internal pressure of the molten resin tube 48 can be reliably retained (maintained).

A receiving portion 69 having a female screw 69A formed on the inner circumference is attached to the inner circumference of the pressure holding jig 60 near the axial end on the attachment 50 side. The female screw 69A of the receiving portion 69 is screwed into the male screw 59A of the fastening portion 59 of the attachment 50 described above, so that the pressure holding jig 60 is attached and fixed to the tip of the attachment 50 . In this embodiment, the pressure holding jig 60 is connected to the tip of the attachment 50 and is cantilevered.

In this embodiment, the outer diameter of the pressure holding jig 60 is formed to be substantially the same as the outer diameter of the attachment 50 (the large-diameter portion having the terminal surface portion 52C). The pressure holding jig 60 is attached to the tip of the attachment 50 with the axial end on the attachment 50 side in contact with the attachment 50 (the large-diameter portion having the terminal surface portion 52C). It should be noted that the mounting structure of the pressure holding jig 60 to the attachment 50 is not limited to the illustrated example.

(Production method of liner)
Next, a method for manufacturing the liner 10 of this embodiment will be described with reference to FIGS. 1 to 3. FIG. The liner 10 is continuously manufactured by sequentially repeating the following steps.

First, as shown in FIGS. 2 and 3, a molten resin heated and melted in a resin feeder (not shown) disposed upstream of the linear travel region P is passed through the outer die 44 of the nozzle 40. A substantially cylindrical molten resin tube 48 is continuously extruded at a constant speed from a resin discharge port 47 through a gap (resin supply path 46 ) between the inner die 42 . At this time, the molten resin tube 48 is a substantially cylindrical resin in a non-solidified state, and its extrusion direction S is the running direction of the first outer mold portion 32 and the second outer mold portion 34 in the straight running region P. is approximately the same as

The extruded molten resin tube 48 flows over the outer peripheral surface (guide surface) 52 of the attachment 50 arranged on the downstream side of the nozzle 40 from the starting end surface portion 52A to the intermediate widened portion 52B. At this time, the intermediate widened portion 52B guides radially outward as it goes downstream (in other words, toward the direction inclined outward with respect to the extrusion direction S), and is guided downstream of the linear travel region P (in other words, , the downstream side in the direction of resin supply), the diameter gradually increases.

In the molten resin tube 48 guided by the outer peripheral surface (guide surface) 52 of the attachment 50, the first outer mold portion 32 and the second outer mold portion 34 circulate in the first direction R1 and the second direction R2, respectively. In this state, the plurality of mold blocks 36 of the first outer mold portion 32 and the plurality of second outer mold portions 34 are moved from the upstream side of the linear travel region P in a direction inclined radially outward with respect to the extrusion direction S. It is continuously supplied at a constant speed in a non-solidified state between itself and the mold block 38 .

Simultaneously with the supply of the molten resin tube 48, a gas supplied from a gas pressure applying device (not shown) passes through the inside of the inner die 42 and the gas supply path 49 (including the gas discharge path 54) inside the attachment 50. The gas is supplied (pumped) to the inside of the molten resin tube 48 from the gas supply port 55 . At this time, by the plurality of inclined supply paths 54B of the gas discharge path 54, the gas is supplied in a direction inclined radially outward (in other words, in a direction inclined outward with respect to the extrusion direction S) in the molten resin. It is supplied (pumped) inside the tube 48 . By supplying the gas, the gas pressure in the hollow portion of the molten resin tube 48 is increased, the gas pressure is applied to the molten resin tube 48 from the inside, and the molten resin tube 48 is pushed into the plurality of molds of the first outer mold portion 32. It is pressed against the block 36 and the plurality of mold blocks 38 of the second outer mold part 34 (the molding surface having suction openings for mold transfer). In addition, by supplying the gas radially outward to the inside of the molten resin tube 48, the gas pressure is applied to the molten resin tube 48 radially outward from the inside (in other words, the molten resin tube 48 is pushed radially outward by the gas pressure), and this also causes the diameter of the molten resin tube 48 to gradually expand toward the downstream side of the linear travel region P (in other words, the downstream side in the resin supply direction), The molten resin tube 48 is pressed against the plurality of mold blocks 36 of the first outer mold section 32 and the plurality of mold blocks 38 of the second outer mold section 34 (molding surface having suction openings for mold transfer).

Here, without the pressure holding jig 60 of the present embodiment, the gas supplied to the inside of the molten resin tube 48 is sequentially discharged to the outside through the neck portion 16 of the liner 10 during molding, and the molten resin tube It becomes difficult to maintain gas pressure in the cavity of 48 .

In this embodiment, as shown in FIGS. 1 and 2, the pressure holding jig 60 held by the attachment 50 is inserted through the necks 16 formed at both axial ends of the liner 10 during molding. The opening (area) of the neck portion 16 narrows (reduces) by the cross-sectional area of the pressure holding jig 60 . As a result, the flow resistance at the neck portion 16, which is a small diameter portion, increases, and the gas supplied to the inside of the molten resin tube 48 is less likely to be discharged from the neck portion 16 of the liner 10 during molding. The gas stays inside the molten resin tube 48, and the gas pressure in the hollow portion of the molten resin tube 48 can be easily maintained (that is, the pressure retaining effect can be enhanced).

Here, in order to efficiently enhance the pressure holding effect, the pressure holding jig 60 and the neck portion 16 of the liner 10 during molding (in other words, the two neck molding portions 26 of the plurality of mold blocks 36 and 38 are pressed against each other). The (annular) clearance area with the molten resin tube 48) is set to be equal to or less than the minimum channel cross-sectional area of the gas discharge path 54 formed in the attachment 50 described above.

Due to this holding pressure effect, the molten resin tube 48 is allowed to open the plurality of mold blocks 36 of the first outer mold section 32 and the plurality of mold blocks 38 of the second outer mold section 34 (the suction openings for mold transfer are opened). molding surface).

A plurality of suction openings (not shown) for sucking the molten resin tube 48 and transferring the mold are formed at a plurality of locations on the inner surfaces of the plurality of mold blocks 36 and 38 . Therefore, between the plurality of mold blocks 36 of the first outer mold portion 32 and the plurality of mold blocks 38 of the second outer mold portion 34, the downstream side of the molten resin tube 48 has a positive pressure and the upstream side has a negative pressure. ing.

Thereby, a substantially cylindrical liner 10 is formed. During this molding process, the first outer mold section 32 and the second outer mold section 34 continue to circulate (i.e., the plurality of mold blocks 36 of the first outer mold section 32 and the plurality of mold blocks of the second outer mold section 34). The relative positions of the block 38 and the nozzle 40 continue to change), and the molten resin tube 48 is formed in the linear travel region P and sequentially transported from upstream to downstream.

The liner 10 that is continuously molded as described above is pressed against the plurality of mold blocks 36 of the first outer mold section 32 and the plurality of mold blocks 38 of the second outer mold section 34, and the mold blocks 36, 38 It is hardened by provided cooling means (not shown) and transported downstream of the straight travel zone P as shown in FIG. The liner 10 is obtained by cutting with a cutter.

(Effect)
As described above, in extrusion corrugated tube molding, the molten resin tube 48 extruded from the resin discharge port 47 draws down under the influence of gravity. As a result, the upper portion of the molten resin tube 48 is less likely to come into contact with (stick to) the mold, making it difficult to shape along the mold.

The apparatus 30 for manufacturing the liner 10 of the present embodiment is configured to discharge the mold blocks 36 and 38 and the tubular molten resin into the mold blocks 36 and 38, while the relative positions of the mold blocks 36 and 38 in the axial direction are adjusted. a resin discharge port (resin discharge port 47) capable of changing the resin discharge portion, a shape adjustment portion (shape adjustment attachment 50) for enlarging the diameter of the cylindrical molten resin discharged from the resin discharge portion, and the resin discharge and a pressure holding part (pressure holding jig 60) capable of holding the internal pressure of the tubular molten resin discharged from the part.

Further, the shape adjusting portion (shape adjusting attachment 50) discharges gas in a direction inclined radially outward inside the cylindrical molten resin discharged from the resin discharging portion (resin discharge port 47). The pressure holding portion (pressure holding jig 60) is axially pressed in the mold blocks 36, 38 by the pressure of the gas against the mold blocks 36, 38. A pressure holding jig 60 extends through the inner side of the narrowest diameter portion of the cylindrical resin.

In addition, the clearance area between the small diameter portion and the pressure holding jig 60 passing through the inside of the small diameter portion is equal to or smaller than the minimum channel cross-sectional area of the gas discharge path 54 .

That is, the apparatus 30 for manufacturing the liner 10 of the present embodiment uses the pressure holding jig 60 to shape the liner 10 while applying internal pressure to the liner 10 by extrusion corrugated tube molding. Gas (blow air) is supplied from the gas pressure applying device, and the clearance between the small diameter portion of the molded liner 10 and the pressure holding jig 60 is reduced, so that the gas (blow air) is injected into the liner 10 during molding ( (inside the molten resin tube 48), and static pressure is applied to the inside of the liner 10 (inside the molten resin tube 48). The molten resin tube 48 extruded from the resin discharge port 47 is adhered to the mold by the internal pressure, so stable molding is possible.

As described above, according to the present embodiment, when forming a tubular body by extrusion corrugated tube molding, the pressure holding portion (using the pressure holding jig 60) applies an internal pressure to the tubular molten resin. Since the resin is shaped, the resin extruded from the resin discharge part (resin discharge port 47) is quickly adhered to the inner walls of the mold blocks 36 and 38, thereby preventing molding defects due to drawdown and enabling stable molding. Become.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications are possible without departing from the scope of the invention. For example, in the above-described embodiment, by moving the plurality of mold blocks 36 of the first outer mold section 32 and the plurality of mold blocks 38 of the second outer mold section 34, the mold blocks 36 and 38 and the nozzle 40 (the resin An example of changing the relative position in the axial direction with the ejection port 47) etc. has been shown, but by moving the nozzle 40 (the resin ejection port 47) etc., the axial direction of the mold blocks 36, 38 and the nozzle 40 etc. can be changed. You may change the relative position in .

10 Liner (pipe)
12 Body portion 14 Dome portion 16 Neck portion 30 Manufacturing device 32 First outer mold portion 34 Second outer mold portion 36 Plural mold blocks 38 Plural mold blocks 40 Nozzle 42 Inner die 44 Outer die 46 Resin supply path 47 Resin discharge port ( resin discharge part)
48 molten resin tube 49 gas supply path 50 shape adjustment attachment (shape adjustment unit)
52 outer peripheral surface (guide surface)
54 gas discharge path 55 gas supply port 60 pressure holding jig (pressure holding portion)
P straight running region R1 first direction (circulation direction of the first outer mold portion)
R2 second direction (circulation direction of the second outer mold section)

Claims (9)

An apparatus for manufacturing a tubular body molded into a cylindrical or tubular shape,
a mold block;
a resin discharge unit capable of changing its relative position in the axial direction with respect to the mold block while discharging cylindrical molten resin into the mold block;
a shape adjusting unit for enlarging the diameter of the tubular molten resin discharged from the resin discharging unit;
A manufacturing apparatus, comprising: a pressure holding section capable of holding an internal pressure of the tubular molten resin discharged from the resin discharging section. In the tubular body manufacturing apparatus according to claim 1,
The shape adjusting section is configured to include a gas discharge path for discharging gas in a direction inclined radially outward within the cylindrical molten resin discharged from the resin discharge section. manufacturing equipment. In the tubular body manufacturing apparatus according to claim 2,
The gas discharge path includes a central supply path that extends in the axial direction, and branches in a direction that is inclined radially outward from the central supply path and opens into the cylindrical molten resin that is discharged from the resin discharge portion. and a plurality of slanted supply paths. In the tubular body manufacturing apparatus according to claim 1,
The manufacturing apparatus, wherein the shape adjustment section includes a guide surface that guides the cylindrical molten resin discharged from the resin discharge section radially outward toward the downstream side. In the tubular body manufacturing apparatus according to claim 1,
The manufacturing apparatus, wherein the shape adjustment section is provided at the discharge side end of the resin discharge section. In the tubular body manufacturing apparatus according to claim 1,
The manufacturing apparatus, wherein the pressure holding portion is configured by a pressure holding jig extending along the axial direction within the mold block. In the tubular body manufacturing apparatus according to claim 1,
The manufacturing apparatus, wherein the holding pressure section is connected to and held by the shape adjusting section. In the tubular body manufacturing apparatus according to claim 1,
The shape adjusting portion includes a gas discharge path for discharging gas in a direction inclined radially outward from the cylindrical molten resin discharged from the resin discharge portion,
The holding pressure portion extends along the axial direction within the mold block and through the inner side of a small diameter portion having the smallest diameter of the tubular resin pressed against the mold block by the pressure of the gas. A manufacturing apparatus characterized by comprising a tool. In the tubular body manufacturing apparatus according to claim 8,
A manufacturing apparatus according to claim 1, wherein a clearance area between the small-diameter portion and the pressure-holding jig passing inside the small-diameter portion is equal to or less than a minimum channel cross-sectional area of the gas discharge path.

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