JP2001205686A - Manufacturing device for hollow extrusion molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a hollow extrusion molding of a desired shape without incurring the expansion of an installation space and the deterioration of productivity. SOLUTION: This manufacturing device for a hollow extrusion molding is made up of an inner layer extrusion molding head 10 for extrusion-molding an inner layer (x) of a rubber material and an intermediate layer extrusion- molding head 20 for extrusion-molding an intermediate layer (y) of a synthetic resin material, formed in a single piece together with an insulating material 40 interposed in between. The intermediate layer (y) is extrusion-molded from the intermediate layer extrusion-molding head 20 directly onto the outer surface of the inner layer (x) extrusion-molded from the inner layer extrusion-molding head 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for producing a multi-layer hollow extruded product in which a second molding layer made of a synthetic resin material is provided on an outer surface of at least a first molding layer made of a rubber material. Regarding improvement.

[0002]

2. Description of the Related Art FIG. 5 shows a manufacturing apparatus of this kind. As shown in FIG. 4, this manufacturing apparatus has a hollow hose having a circular cross section (hereinafter referred to as a three-layer hose Q) having an intermediate layer y made of a synthetic resin material between an inner layer x made of a rubber material and an outer layer z. A first extrusion head A for extruding the inner layer x, a second extrusion head B for extruding the intermediate layer y, and a third extrusion head for extruding the outer layer z. And a head C.

Although not shown in the drawings, each of the extrusion heads A, B, and C is formed in a cylindrical shape so that a material supplied from the outer peripheral surface is extruded from one inner peripheral surface at one end. And a so-called crosshead, which are arranged side by side with their axes aligned. The first extruding head A and the third extruding head C are each connected to a rubber extruder D for supplying a rubber material of about 120 ° C., while the second extruding head B is A synthetic resin extruder E for supplying a synthetic resin material of about 200 ° C. is connected.

In this manufacturing apparatus, first, a tubular inner layer x extruded from a first extrusion head A is sequentially supplied to a second extrusion head B, and a second inner extrusion layer B is provided on the outer periphery of the inner layer x. The intermediate layer y extruded from the extrusion head B is covered.

Next, the inner layer x coated with the intermediate layer y is sequentially supplied to the third extrusion head C, and the outer layer z extruded from the third extrusion head C is coated on the outer periphery of the intermediate layer y. As a result, the inner layer x, the intermediate layer y, and the outer layer z are in a state of being laminated on each other.

Thereafter, these three molded layers x, y, z are cooled in a cooling tank F, and furthermore, an inner layer x made of rubber material is used.
And the outer layer z is vulcanized, so that a three-layer hose Q having desired physical properties can be obtained.

[0007]

The inner layer x extruded from the first extrusion head A is a rubber material before vulcanization, and therefore has extremely low rigidity, and it is difficult to maintain its own shape. It is in a state.

Accordingly, there is a possibility that the inner layer x extruded from the first extrusion molding head A hangs down by gravity before reaching the second extrusion molding head B, the hollow portion is crushed, and the like. This has a great effect on the shape and dimensions of the three-layer hose Q.

For this reason, in the conventional manufacturing apparatus, the mandrel G is applied as a core material to prevent the above-mentioned situation from occurring. That is, the mandrel G having a predetermined rigidity is supplied to the first extrusion head A, and the inner layer x is extruded on the outer periphery of the mandrel G, thereby forming the inner layer x up to the second extrusion head B. This prevents a situation such as drooping or crushing from occurring.

According to the manufacturing apparatus to which the mandrel G is applied, the inside diameter of the three-layer hose Q is accurately defined by the outside diameter of the mandrel G, which is extremely advantageous in terms of dimensional accuracy.

However, in the manufacturing apparatus described above, a device H for supplying the mandrel G and a device J for applying a predetermined tension to the mandrel G are arranged upstream of the first extrusion head A. Must be performed, which leads to a significant increase in the installation space. Further, after vulcanizing the inner layer x and the outer layer z, it is necessary to pull out the mandrel G from the three-layer hose Q,
It is not preferable in terms of productivity.

The present invention has been made in view of the above circumstances, and has as its object to provide a manufacturing apparatus capable of obtaining a hollow extruded product having a desired shape without causing an increase in installation space and a decrease in productivity. And

[0013]

According to the first aspect of the present invention, there is provided a hollow extruded product having at least a first molding layer made of a rubber material and an outer surface provided with a second molding layer made of a synthetic resin material. A first extrusion head for extruding said first molding layer and said second extrusion head.
And a second extruding head for extruding the molded layer of the first extruded layer into an integral unit with a heat insulating material interposed therebetween, and the first extruded head extruded from the first extruded head. The second extrusion layer is immediately extruded from the second extrusion head onto the outer surface of the extrusion layer.

Further, in the invention according to claim 2 of the present application, a second molding layer made of a synthetic resin material and a third molding layer made of a rubber material are sequentially formed on at least the outer surface of the first molding layer made of a rubber material. In the apparatus for manufacturing a hollow extruded product provided, a first extrusion head for extruding the first molding layer and a second extrusion head for extruding the second molding layer are mutually connected. Into an integrated unit with a heat insulating material interposed therebetween, and the third unit
A third extrusion head for extruding a molded layer of the first extruded layer is disposed in the vicinity of the unit, and the second extruded head is extruded from the first extruded head immediately on the outer surface of the first molded layer. The second molding layer is extruded from an extrusion head, and the third molding layer is immediately extruded from the third extrusion head onto the outer surface of the second molding layer.

In these manufacturing apparatuses, a ventilation passage for opening a space defined between the outer peripheral surface of the first molding layer extruded from the first extrusion molding head and the unit to the outside of the unit is provided. Preferably, it is provided.

Further, in the invention according to claim 2 of the present application, it is preferable to provide an adjusting means for adjusting a separation distance between the unit and the third extrusion head. Third
From the third extrusion head so as to support the outer periphery of the second molding layer extruded from the second extrusion head.
Is preferably extruded. In the third extrusion head, if the extrusion port of the rubber material to be the third molding layer is located closer to the unit than the supply port of the rubber material, the third molding layer is extruded near the unit. It is possible to do. In this case, it is preferable to provide a supporting means for supporting the outer periphery of the third molding layer in the third extrusion head.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings showing embodiments. FIGS. 1 to 3 show an embodiment of the production apparatus according to the present invention. As shown in FIG. 4, an inner layer (first molded layer) made of a rubber material as a hollow extruded product. x and outer layer (third molded layer)
An apparatus for manufacturing a three-layer hose Q having a circular cross section in which an intermediate layer (second molded layer) y made of a synthetic resin material is provided as a gas barrier layer between z. An example of the specific dimensions of the three-layer hose Q manufactured by the manufacturing apparatus according to the present embodiment is as follows.
64 mm and a thickness of 2.24 to 2.33 mm, a thickness of the intermediate layer y of 0.13 to 0.14 mm, and an outer diameter of the outer layer z of 18.
10 to 18.20 mm.

As shown in FIG. 1, the manufacturing apparatus includes an inner layer extrusion head 10 serving as a first extrusion head,
Intermediate layer extrusion head 20 serving as a second extrusion head
And an outer layer extrusion head 3 serving as a third extrusion head
0 is provided.

The inner layer extrusion head 10 is for extruding the inner layer x of the above-described three-layer hose Q, and has an inner layer torpedo 12, an inner layer collar 13 and an inner layer die holder in a center hole of a cylindrical inner layer head body 11. 14 is provided.

The inner layer torpedo 12 is provided with a spider 12b at the base end of a substantially cylindrical base 12a.
With the axis of the base portion 12a aligned with the axis of the inner layer head main body 11, the inner layer head main body 1 is connected via the spider 12b.
1 is held at the base end. The inner layer nipple 15 is held at the tip of the base 12a of the inner layer torpedo 12. The inner layer nipple 15 has a substantially cylindrical shape whose outer diameter decreases toward the tip, and extends from the tip of the inner layer torpedo 12 with its axis aligned with the axis of the inner layer head body 11. I have. The tip of the inner nipple 15 is
The outer diameter is configured to define the inner diameter of the inner layer x in the above-described three-layer hose Q.

The base 1 of the inner layer torpedo 12
The 2a and the inner nipple 15 are provided with blow holes 12c and 15a communicating with each other at positions that are the respective axes. The blow holes 12 c and 15 a are provided with the inner nipple 15.
The spider 12b of the inner layer torpedo 12 is closed at the base end of the base 12a while opening at the front end surface of the base 12a.
Through the communication passage 12d provided in the inner head body 11 and the communication passage 11a provided in the inner head body 11. Although not explicitly shown in the drawing, the communication passage 11a of the inner layer head main body 11 has
An air blow device for injecting air from the tip openings of c and 15a may be connected.

Inner Layer Collar 13 and Inner Layer Die Holder 14
Are formed in the center hole of the inner layer head main body 11 so as to be continuous with the above-described spider 12b of the inner layer torpedo 12, respectively. The central holes of the inner-layer collar 13 and the inner-layer die holder 14 are configured such that the inner diameter gradually decreases toward the distal end, and forms a tapered flow path. As is apparent from the figure, the tip of the inner layer die holder 14 projects further from the tip of the inner layer head main body 11 toward the tip, and its outer peripheral portion is surrounded by the inner layer die holder retainer 16 while its inner periphery is The part holds the inner layer die 17. Inner die holder holder 1
Reference numeral 6 denotes an annular shape, which is attached to the distal end surface of the inner layer head main body 11 in a state of being engaged with the distal end of the inner layer die holder 14. The inner layer die 17 has an annular shape so as to surround the outer peripheral portion of the inner layer nipple 15. The center hole of the inner layer die 17 is provided so as to be continuous with the center hole of the inner layer die holder 14, and the inner diameter of the foremost portion thereof is configured to define the outer diameter of the inner layer x in the above-described three-layer hose Q. It is.

The inner layer die 17 is provided with a plurality of ventilation passages 17a. Each of the ventilation passages 17 a extends obliquely from the outer peripheral surface at the base end of the inner layer die 17 toward the center of the distal end surface of the inner layer die 17. These ventilation passages 17a communicate with each other at their base ends through an annular passage 17b provided on the outer peripheral surface of the base end of the inner layer die 17, and further have a communication passage 14a provided at the inner layer die holder 14 and a communication passage provided at the inner layer die holder holder 16. An opening is formed in the outer peripheral surface of the inner layer die holder retainer 16 through the passage 16a. Although not explicitly shown in the drawing, a vacuuming device for sucking gas from the distal end surface of the ventilation passage 17a may be connected to the communication passage 16a of the inner layer die holder retainer 16.

Reference numeral 18 in the drawing denotes an inner layer head adjusting bolt screwed from the outer peripheral surface of the inner layer head main body 11 toward the inner layer die holder 14. The inner layer head adjusting bolt 18 is connected to the inner layer die 17 via the inner layer die holder 14.
Is to adjust the position with respect to the inner layer nipple 15. Reference numeral 19 in the drawing denotes the inner layer head main body 11.
Is a jacket for circulating hot water provided on the outer peripheral surface of the device.

The inner layer extrusion head 10 is connected to the inner layer rubber extruder 100 with the center hole of the inner layer head body 11 aligned with the center hole of the liner 101 and the breaker plate 102 interposed therebetween. I have. The inner layer rubber extruder 100 is a 60 mm rubber uniaxial vent type extruder (L / D = 16), and the screw 103 is set to 6.5 r.
pm, and supplies an unvulcanized rubber material at about 120 to 130 ° C. to the inner layer extrusion molding head 10 described above.

The intermediate layer extrusion head 20 is for extruding the intermediate layer y of the three-layer hose Q described above. The intermediate layer nipple 22 and the intermediate layer A die holder 23 is provided.

The intermediate layer nipple 22 has a bottomed annular shape and has a through hole 22a in the center of the bottom wall.
The bottom wall is fitted to the base end of the center hole of the intermediate layer head body 21 with the bottom wall facing outward. The through hole 22 a provided in the bottom wall of the intermediate layer nipple 22 has an inner diameter slightly larger than the inner diameter of the inner layer die 17 in the inner layer extrusion head 10 described above.

The intermediate layer die holder 23 has a substantially cylindrical shape having substantially the same length as the intermediate layer head main body 21, and holds the intermediate layer die 24 on the inner peripheral portion of the base end thereof, while holding the distal end thereof. A flange 23a is provided on the outer peripheral portion. The intermediate layer die 24 has a bottomed cylindrical shape and has a center hole slightly larger in diameter than the through hole 22a of the intermediate layer nipple 22 at the center of the bottom wall. It is attached to the intermediate layer die holder 23 in a state facing the side. The base end face of the intermediate layer die holder 23 and the base end face of the intermediate layer die 24 are located on the same plane at a position slightly separated from the bottom wall of the intermediate layer nipple 22.

As shown in FIG. 2, the intermediate layer die holder 23 has an outer diameter at the base end slightly smaller than the outer diameter at the distal end, and at the distal end, the intermediate layer head main body 21 has a smaller diameter. , While being slightly separated from the center hole of the intermediate layer head main body 21 at the base end. Further, a spiral groove 23b is formed on the outer peripheral surface of the intermediate layer die holder 23.
The spiral groove 23b forms a spiral flow path from the distal end side to the proximal end side with the inner peripheral surface of the intermediate layer head main body 21. In this flow path, the downstream end located on the base end side of the intermediate layer head main body 21 is a space defined between the base end surfaces of the intermediate layer die holder 23 and the intermediate layer die 24 and the bottom wall of the intermediate layer nipple 22. And is opened so as to be substantially perpendicular to the axis of the intermediate layer head main body 21. On the other hand, the upstream end of the flow path located on the distal end side of the intermediate layer head main body 21 is opened to the outer peripheral surface of the intermediate layer head main body 21 through a communication passage 21 a provided in the intermediate layer head main body 21.

Reference numeral 25 in FIG. 1 denotes an electric heater surrounding the outer periphery of the intermediate layer head main body 21.

The intermediate layer extrusion head 20 has a structure in which the axis of the intermediate layer head main body 21 is aligned with the axis of the inner layer head main body 11 and the heat insulating material 40 is interposed therebetween.
It is configured as a unit integral with the inner layer extrusion head 10 described above. That is, in the state where the heat insulating material 40 is interposed between the distal end surface of the inner layer die holder 14 in the inner layer extrusion head 10 and the base end surface of the intermediate layer head main body 21 in the intermediate layer extrusion head 20, both are unit bolts 41
Is firmly fixed. The heat insulating material 40 has sufficient rigidity to maintain the connection between the two,
What has heat resistance enough to withstand a high temperature of 0 ° C. or more may be used. As is clear from FIG. 2, the heat insulating material 40 has a plate thickness larger than the protrusion amount of the inner layer die 17 from the inner layer die holder 14, and the tip surface of the inner layer die 17 and the intermediate layer nipple 22 are formed. A heat insulating space α is secured between the base end face.

Further, the synthetic resin extruder 2 is connected to the intermediate layer extrusion molding head 20 via an intermediate layer relay head 50.
Connected to 00. The intermediate layer relay head 50 is a portion that communicates with the communication passage 21 a of the intermediate layer head main body 21 and extends radially outward from the intermediate layer head main body 21. The intermediate layer relay head 50 is provided with an electric heater 51 at a position corresponding to an outer peripheral portion of the flow path. The synthetic resin extruder 200 is a 40 mm plastic extruder,
The screw 201 is driven at 1.65 rpm to supply a synthetic resin material of about 200 to 240 ° C., for example, THV (fluorothermoplastic) to the above-described intermediate layer extrusion molding head 20. Reference numeral 202 in the drawing denotes a breaker plate interposed between the intermediate layer relay head 50 and the synthetic resin extruder 200.

The outer layer extrusion molding head 30 is for extruding the outer layer z of the three-layer hose Q described above, and has an outer layer nipple holder 32 and an outer layer die holder 33 in a center hole of a cylindrical outer layer head body 31. ing.

The outer layer nipple holder 32 has an annular shape having a smaller diameter at the base end side than at the front end, and is attached to the base end of the outer layer head main body 31 via the outer periphery at the front end. The center hole of the outer layer nipple holder 32 is configured to be continuous with the center hole of the outer layer head main body 31 at the distal end and to gradually decrease the inner diameter toward the base end. The outer layer nipple holder 32 holds an outer layer nipple 34 at the inner peripheral portion of the base end. The outer layer nipple 34 has an annular shape, and has a center hole having two inner peripheral surfaces 34a and 34b. An inner peripheral surface located on the proximal end side of the outer layer nipple 34 (hereinafter, referred to as an introduction inner peripheral surface 34a) extends so as to gradually decrease its inner diameter toward the distal end. The inner diameter of the most proximal portion of the inner circumferential surface 34a is larger than the inner diameter of the most distal portion of the center hole of the intermediate layer die holder 23 described above. On the other hand, the inner peripheral surface (hereinafter, referred to as a flow path defining inner peripheral surface 34b) located on the distal end side of the outer layer nipple 34 extends so that the inner diameter gradually decreases toward the proximal end, and then returns to the proximal end side. And is associated with the leading end of the introduction-side inner peripheral surface 34a. The flow path defining inner peripheral surface 34 b is configured such that the inner diameter of the leading end portion is continuous with the center hole of the outer layer nipple holder 32.

The outer layer die holder 33 includes the outer layer head body 3.
1 has a substantially columnar shape having substantially the same length as that of the first die 1 and holds an outer die 35 at a base end thereof.
Are fitted and held in the center hole of the outer layer head main body 31 in a state of facing the outer layer nipple 34. In the outer layer die holder 33, a thin portion 33a is formed from the outer peripheral side to the base end portion including the outer layer die 35, and from the inner peripheral surface of the outer layer head main body 31 to the flow path defining inner peripheral surface 34b of the outer layer nipple 34. A flow path from the distal end to the proximal end is formed between the leading portions. The downstream end located on the base end side of the outer layer head main body 31 in this flow path is formed by a gap between the inner end of the flow path defining inner peripheral surface 34 b of the outer layer nipple 34 and the base end of the outer layer die 35. It is open toward the axis of the outer layer head main body 31 through the outlet 36. On the other hand, the upstream end portion of the flow path located on the distal end side of the outer layer head main body 31 has a portion serving as the supply port 33b.
1 is open to the outer peripheral surface of the outer layer head main body 31 through a communication passage 31 a provided in the main body 1.

The outer layer die holder 33 is configured such that the inner diameter of the center hole gradually increases toward the tip, and includes an outer layer guide roller 37 as a support means inside. The outer layer guide roller 37 is for supporting the three-layer hose Q passing through the inside of the outer layer extrusion head 30 from below inside the outer layer extrusion head 30.

Reference numeral 38 in the drawing denotes an outer layer head adjustment bolt screwed from the outer peripheral surface of the outer layer head main body 31 to the outer layer nipple holder 32. The outer layer head adjusting bolt 38 is for adjusting the position of the outer layer nipple 34 with respect to the outer layer die 35 via the outer layer nipple holder 32. Reference numeral 39 in the drawing denotes a jacket for circulating hot water provided on the outer peripheral surface of the outer layer head main body 31.

The outer layer extrusion head 30 is disposed on the extension of the tip of the intermediate layer head main body 21 in a state where the axis of the outer layer head main body 31 matches the axis of the intermediate layer head main body 21. It is connected to the outer layer rubber extruder 300 via the outer layer relay head 60. Outer layer relay head 6
0 communicates with the communication passage 31a of the outer layer head main body 31,
Further, it is a portion extending from the outer layer head main body 31 in a radially outward direction. The outer layer relay head 60 is provided with a warm water circulation jacket 61 at a position that is an outer peripheral portion of the flow path.
The outer layer rubber extruder 300 is a 90 mm rubber uniaxial vent type extruder (L / D = 16).
The one which drives at 7 rpm and supplies the unvulcanized rubber material at about 120 to 130 ° C. to the above-mentioned outer layer extrusion head 30 is applied. As shown in FIG. 3, the outer layer rubber extruder 300 is installed on a table (adjusting means) 310 movable along the direction in which the three extrusion heads 10, 20, and 30 are juxtaposed. , The table 3
By moving the head 10, the distance between the outer layer extrusion head 30 and the intermediate layer extrusion head 20 can be adjusted. Reference numeral 302 in the drawing denotes a breaker plate interposed between the outer layer relay head 60 and the outer layer rubber extruder 300.

In the manufacturing apparatus configured as described above, when the inner layer rubber extruder 100 is driven, the rubber material supplied to the inner layer extrusion head 10 is sequentially extruded from between the inner layer die 17 and the inner layer nipple 15. Then, it is supplied to the intermediate layer extrusion head 20 as an inner layer x having a desired shape. During this time, it is preferable to drive the air blow device (not shown) to constantly inject air from the tip openings of the blowing holes 12c and 15a so that the inner layer x maintains a desired shape by the pressure of the air.

In the intermediate layer extrusion molding head 20 supplied with the inner layer x, the synthetic resin material is sequentially extruded and formed from between the intermediate layer nipple 22 and the intermediate layer die 24 by the driving of the synthetic resin extruder 200, and is drawn down. As a result, it becomes the intermediate layer y and covers the outer periphery of the inner layer x. During this time, the vacuum pump (not shown) is driven to suck the gas in the adiabatic space α through the ventilation passage 17a, so that the inner layer x
It is preferable to prevent gas from entering between the intermediate layer y.

The inner layer x covered by the intermediate layer y is further supplied to the outer layer extrusion head 30. In the outer layer extrusion head 30, the rubber material is sequentially extruded and formed from between the outer layer nipple 34 and the outer layer die 35 by driving the outer layer rubber extruder 300, and becomes an outer layer z to form the intermediate layer y.
And the inner layer x and the intermediate layer y
And the outer layer z are laminated.

Thereafter, the three molded layers x, y, and z are cooled in the cooling tank 400, and the inner layer x and the outer layer z, which are rubber materials, are vulcanized to obtain a three-layer hose Q having desired physical properties. Will be able to gain.

According to the above-described manufacturing apparatus, the inner layer extrusion head 10 and the intermediate layer extrusion head 20 are formed as an integral unit, and the inner layer x extruded from the inner layer extrusion head 10 is immediately intermediately formed. Since the coating is performed by the layer y, the inner layer x, which is a rubber material before vulcanization extruded and formed from the inner layer extrusion molding head 10, may be deformed such as hanging down by gravity or crushing a hollow portion. Absent. Further, since the outer layer extrusion head 30 is disposed near the intermediate layer extrusion head 20 and the intermediate layer y is immediately covered with the outer layer z, the above-described effects are more remarkable. In addition, the outer layer extrusion head 3
0, the outer layer guide roller 37 is disposed inside.
The outer layer z extruded from the outer layer extrusion head 30 can be supported at a closer position. Therefore,
A three-layer hose Q having a desired shape can be obtained without using a mandrel as before, and there is no fear that the use of the mandrel increases the installation space or lowers productivity. In this case, a non-contact type outer diameter measuring device s is installed between the intermediate layer extrusion head 20 and the outer layer extrusion head 30 and on the downstream side of the outer layer extrusion head 30, respectively. By performing dimensional control such as controlling the driving of each of the extruders 100, 200, and 300 based on this, the dimensional accuracy of the three-layer hose Q can be further improved. When the inner core x, the intermediate layer y, and the outer layer z are stacked on each other, a curved core rod is inserted into the inner layer x, and then the inner layer x and the outer layer z are vulcanized. It is also possible to obtain a curved three-layer hose Q.

Further, according to the manufacturing apparatus, the heat insulating material 40 is interposed between the inner layer extrusion head 10 and the intermediate layer extrusion head 20, and the heat insulation space α is secured. Can be properly maintained,
For example, there is no danger that the rubber material of the inner layer extrusion molding head 10 is vulcanized due to high temperature, or conversely, the synthetic resin material of the intermediate layer extrusion molding head 20 cools and the fluidity becomes poor. Further, the intermediate layer y, which has a higher temperature than the inner layer x and the outer layer z, is cooled before covering the inner layer x, and has a small thickness of 0.13 to 0.14 mm and a small heat capacity. There is no possibility that heat will affect the unvulcanized rubber material that becomes the outer layer z. In particular, as for the outer layer z, the outer layer extrusion head 3 for extruding the outer layer z is used.
0 is movable with respect to the intermediate layer extrusion head 20, so that the position of the intermediate layer y
It is possible to surely prevent the influence of the heat.

In the outer layer extrusion head 30, the outer layer z is extruded toward the axis of the outer layer head body 31, so that the inner layer x covered by the intermediate layer y is extruded. The support can be provided by the molding force, and it is possible to prevent the middle layer y from being scratched by the contact with the outer layer nipple 34.

In the above-described embodiment, an apparatus for manufacturing a three-layer hose having a circular cross section is exemplified. However, the cross section of the hollow extruded product is not necessarily required to be circular. Further, the number of the formed layers does not need to be three, and may be any number such as four layers or five layers as long as the number is at least two or more.

In the above-described embodiment, the outer extrusion head, which is the third extrusion head, extrudes the third molding layer at a position on the base end side. Although it is possible to cover the second molded layer extruded from the second extrusion head at a position closer to the second molded layer, the third molded layer is not necessarily positioned at the base end side. There is no need to extrude. Although only the third extrusion molding head is provided so as to be movable, only the first and second extrusion molding heads configured as a unit are provided so as to be movable or both are movable so as to be movable. May be provided.

Further, in the above-described embodiment, as the first and third extrusion heads, there are illustrated so-called alignment type heads in which the gap between the die and the nipple is adjusted by adjusting bolts. However, like the intermediate layer extrusion head exemplified as the second extrusion head,
A coreless type may be applied. In addition, as the first extrusion head, a so-called straight head type is illustrated, but a so-called cross head type head may be applied. In this case, it is possible to manufacture a hollow extruded product using a mandrel in the same manufacturing apparatus.

[0049]

As described above, according to the present invention,
For the first molded layer, which is a rubber material before vulcanization extruded from the first extrusion molding head, the second molding layer is a synthetic resin material whose outer surface is immediately extruded from the second extrusion molding head. Since the first molding layer is covered with the molding layer, there is no possibility that the first molding layer will be hung down by gravity or deformed such as a hollow portion being crushed. Therefore, a hollow extruded product having a desired shape can be obtained without using a mandrel as in the past, and there is no fear that the use of the mandrel may increase the installation space or lower the productivity. . In addition, since a heat insulating material is interposed between the first extrusion head and the second extrusion head, the temperatures of both can be appropriately maintained. There is no danger of the rubber material being vulcanized at high temperatures or vice versa, and conversely, the synthetic resin material of the second extrusion head cools and the fluidity becomes poor.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of a manufacturing apparatus according to the present invention.

FIG. 2 is an enlarged sectional view of a main part of the manufacturing apparatus shown in FIG.

FIG. 3 is a diagram conceptually showing the manufacturing apparatus shown in FIG.

FIG. 4 is a perspective view of a three-layer hose shown as an example of a hollow extruded product.

FIG. 5 is a conceptual diagram showing a conventional manufacturing apparatus.

DESCRIPTION OF SYMBOLS 10 Inner layer extrusion head 11 Inner layer head main body 11a Communication passage 12 Inner layer torpedo 12a Base 12b Spider 12c, 15a Blow hole 12d Communication passage 13 Inner collar 14 Inner die holder 14a Communication passage 15 Inner nipple 16 Holder for inner layer die holder Passage 17 Inner layer die 17a Ventilation passage 17b Annular passage 18 Inner layer head adjustment bolt 20 Intermediate layer extrusion molding head 21 Intermediate layer head body 21a Communication passage 22 Intermediate layer nipple 22a Through hole 23 Intermediate layer die holder 23a Flange 23b Spiral groove 24 Intermediate layer die 25 Electric heater 30 Outer layer extrusion molding head 31 Outer layer head main body 31a Communication passage 32 Outer layer nipple holder 33 Outer layer die holder 33a Thin portion 33b Supply port 34 Outer layer nipple 34a Inside of introduction side Surface 34b Flow path defining inner peripheral surface 35 Outer die 36 Extrusion port 37 Outer layer guide roller 38 Outer layer head adjustment bolt 40 Insulation material 41 Unit bolt 50 Intermediate layer relay head 51 Electric heater 60 Outer layer relay head 100 Inner layer rubber extruder 101 Liner 102 Breaker plate 103 Screw 200 Synthetic resin extruder 201 Screw 300 Outer rubber extruder 301 Screw 310 Table 400 Cooling tank Q Three-layer hose s Non-contact type outer diameter measuring device x Inner layer y Intermediate layer z Outer layer α Insulated space

Claims (7)

[Claims] 1. An apparatus for manufacturing a hollow extruded product in which a second molding layer made of a synthetic resin material is provided on an outer surface of at least a first molding layer made of a rubber material, wherein the first molding layer is provided. A first extrusion head for extruding the second extrusion head and a second extrusion head for extruding the second molding layer into an integral unit with a heat insulating material interposed therebetween. Hollow extrusion wherein the second molded layer is immediately extruded from the second extrusion head on the outer surface of the first molded layer extruded from the first extrusion head. Equipment for manufacturing molded products. 2. A hollow extruded product in which a second molding layer made of a synthetic resin material and a third molding layer made of a rubber material are sequentially provided on the outer surface of at least a first molding layer made of a rubber material is manufactured. In the apparatus, a first extruding head for extruding the first molded layer and a second extruding head for extruding the second molded layer have a heat insulating material interposed therebetween. A third extruded head for extruding the third molded layer is arranged near the unit, and the third extruded head extruded from the first extruded head is configured as an integrated unit in the state. Immediately extruding the second molding layer from the second extrusion head on the outer surface of the first molding layer, and further immediately extruding the third molding head from the third extrusion head onto the outer surface of the second molding layer. Forming 3 Hollow extrusion of a manufacturing apparatus is characterized in that as extruding. 3. A ventilation passage for opening a space defined between an outer peripheral surface of a first molding layer extruded from the first extrusion molding head and the unit to the outside of the unit. Item 3. An apparatus for manufacturing a hollow extruded product according to claim 1 or 2. 4. The apparatus for manufacturing a hollow extruded product according to claim 2, further comprising adjusting means for adjusting a separation distance between the unit and the third extrusion head. 5. The third extrusion head is extruded from the third extrusion head so as to support an outer periphery of a second extrusion layer extruded from the second extrusion head. 3. An apparatus for producing a hollow extruded product according to item 2. 6. The third extrusion-molding head includes the third extrusion head.
3. The apparatus for manufacturing a hollow extruded product according to claim 2, wherein an extrusion port of the rubber material to be a molding layer is closer to the unit than a supply port of the rubber material. 7. An apparatus for manufacturing a hollow extruded product according to claim 6, wherein said third extrusion head is provided with support means for supporting an outer periphery of said third molded layer.