JPH0571031B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for manufacturing a rubber hose having a reinforcing layer and an apparatus for manufacturing the same. [Prior art] As a method for manufacturing reinforced rubber hoses, a
As described in Publication No. 128978, an inner rubber layer is extruded around the outer periphery of a mandrel made of metal wire, plastic cloth, etc., and a reinforcing layer made of nylon or the like is formed around the outer periphery of the inner rubber layer. A known method is to extrude an outer rubber layer on the outer periphery, extrude a resin coating layer of plastic such as polysulfone on the outer periphery of the outer rubber layer, vulcanize it as it is, and then remove the resin coating layer. . In addition, as described in the above-mentioned Japanese Patent Application Laid-open No. 52-128978, in addition to fibrous materials such as nylon, rayon, and cotton, thin metal wires have been used as reinforcing layers by braiding or spirally wrapping them. It was known that According to this method, the inner and outer circumferential surfaces of the rubber hose are restrained by the mandrel and the resin coating layer, so that the cross section of the hose can be circular and uniform without using the expensive and complicated leaded vulcanization method. This has the advantage of being able to maintain a constant wall thickness and producing a rubber hose with an excellent appearance. However, if the resin coating layer is extruded immediately after the outer rubber layer is extruded, the outer rubber layer will enter the crosshead of the resin extruder while being very soft, and it will be rubbed by the vacuum packing at the inlet of the crosshead of the resin extruder. The outer rubber layer may be damaged,
There were problems such as clogging during vacuum packing. Conventionally, in order to eliminate scratches on the outer rubber layer, the outer rubber layer surface was naturally cooled or forcedly cooled until it became hard. However, since it takes about 24 hours for the surface of the outer rubber layer to harden when naturally cooled at room temperature, a method of forced cooling as shown in FIG. 4 has usually been used. That is, an inner rubber layer is formed on the outer periphery of the mandrel, a reinforcing layer made of fibers or thin metal wires is formed on the outer periphery of the inner rubber layer, and this hose is sent from the hose feeder 1 to the rubber extruder 2, and the rubber extruder crosshead 3 An outer rubber layer is extruded around the outer periphery of the reinforcing layer while drawing a vacuum through the suction port 11, and then forcedly cooled in the cooling water tank 4. Subsequently, the cooled and hardened hose is supplied to a resin extruder 6 via a take-off machine 5, and a resin coating layer is extruded around the outer periphery of the outer rubber layer while vacuuming from the suction port 12 at the resin extruder crosshead 7. After being forcibly cooled in a cooling water tank 8, it is passed through a take-up machine 9 and wound up into a wind-up machine 10. However, even with this forced cooling, a lead time of about 6 hours was required from the formation of the outer rubber layer to the formation of the resin coating layer, and productivity was still poor. Another way to eliminate scratches on the outer rubber layer is to
It may be possible to make the inner diameter of the vacuum packing provided at the hose inlet of the crosshead 7 of the resin extruder 6 larger than the outer diameter of the outer rubber layer, but if the crosshead 7 of the resin extruder 6 lacks a vacuum, the outer rubber layer and the resin coating may be damaged. Bubbles are formed between the layers and the product does not have a good appearance. It is also possible to use a double-tube extruder in which two extrusion ports for resin or rubber are opened concentrically at approximately the same position, but rubber is simultaneously extruded from the inner extrusion port and resin from the outer extrusion port. If the rubber were to be released, the extrusion pressure would be different, and the extrusion temperature of the resin would be as high as 200 to 340°C, so the rubber would burn or foam, making it impossible to mold. [Problems to be Solved by the Invention] In view of the above-mentioned conventional circumstances, an object of the present invention is to provide a method and a manufacturing apparatus for manufacturing a rubber hose with good surface appearance while restraining the outer peripheral surface with high productivity. . [Means for Solving the Problems] In order to achieve this object, in the present invention, an inner rubber layer is formed on the outer periphery of the mandrel, a reinforcing layer is formed on the outer periphery of the inner rubber layer, and an outer rubber layer is formed on the outer periphery of the reinforcing layer. In a method of manufacturing a rubber hose, the method includes extruding a rubber hose, extruding a resin coating layer around the outer periphery of the outer rubber layer, and removing the resin coating layer after vulcanization.
It is characterized in that the steps from extrusion molding of the outer rubber layer to extrusion molding of the resin coating layer are carried out continuously in a reduced pressure atmosphere. The degree of pressure reduction in the method of the present invention is the same as that conventionally used in the rubber extruder crosshead 3 and resin extruder crosshead 7 shown in FIG.
200-600mmHg. Further, the rubber hose manufacturing apparatus of the present invention includes a rubber extruder crosshead attached to a rubber extruder that extrudes an outer rubber layer on the outer periphery of a reinforcing layer applied to the outer periphery of the inner rubber layer, and a rubber extruder crosshead that is attached to an outlet of the rubber extruder crosshead. A resin extruder crosshead is attached to a resin extruder that extrudes and molds a resin coating layer around the outer periphery of the outer rubber layer to be extruded, and is equipped with an inlet having a larger diameter than the outer rubber layer, an outlet of the rubber resin machine crosshead, and a resin extruder crosshead. A connecting pipe having a diameter larger than that of the outer rubber layer connecting the inlets, and a suction port provided in the connecting pipe and capable of suctioning and exhausting the inside of the connecting pipe and the inside of the hose passage of the resin extruder crosshead to a reduced pressure state. It is characterized by The formation and vulcanization of the inner rubber layer and reinforcing layer, as well as the subsequent peeling off of the resin coating layer and pulling out of the mandrel, can be carried out using the same apparatus and method as conventional ones. [Function] In the present invention, the extrusion molding of the outer rubber layer and the extrusion molding of the resin coating layer can be carried out under reduced pressure while evacuating each crosshead, as well as using a connecting pipe evacuated between both crossheads. Connect and move the rubber hose under reduced pressure. Therefore,
Since the connecting pipe and the resin extruder crosshead can be communicated in a continuous reduced pressure atmosphere, there is no need to provide vacuum packing at the inlet of the resin extruder crosshead, and when the freshly extruded soft outer rubber layer surface enters the resin extruder crosshead, It won't get scratched or clogged by rubbing. If a viewing window is provided in the connecting pipe, it is possible to optically measure the outer diameter of the hose (the outer diameter of the outer rubber layer) from the outside. Furthermore, since the resin extruder crosshead reaches a high temperature of 200 to 340°C, it is preferable to provide a cooling device between the two to suppress heat transfer to the connecting pipe. [Example] Fig. 1 shows a specific example of a rubber hose manufacturing device.
As can be seen from FIG. 2, which shows the main parts thereof, the rubber extruder crosshead 3 and the resin extruder crosshead 7 are connected through a connecting pipe 13 to form a connected crosshead. That is, as is usual in the rubber extruder crosshead 3, a hose passage 17 is formed horizontally within the crosshead body 14 by a spindle holder 15 and a spindle 16 screwed onto the tip thereof. A vacuum packing 19 is provided at the inlet 18 of the hose passage 17, and the inner diameters of this vacuum packing 19 and the outlet of the spindle 16 are made approximately equal to the outer diameter of the reinforcing layer of the hose, and the hose passage 17 is evacuated from the suction port 20. It is now possible to pull it out. Further, a rubber supply path 21 for raw rubber supplied from the rubber extruder 2 is formed in the crosshead body 14, and a die 22 for extruding the outer rubber layer is fixed to the crosshead body 14 at the outlet thereof. It opens concentrically with the exit. A resin extruder crosshead 7 is provided at intervals on the outlet side of the rubber extruder crosshead 3, and the hose of the rubber extruder crosshead 3 is connected to the center line of a hose passage 17' consisting of a spindle holder 15' and a spindle 16'. It is aligned with the center line of the passage 17. A resin supply path 23 is formed in the crosshead body 14' of the resin extruder crosshead 7, and its outlet is connected to the spindle 1 by a die 22'.
It opens concentrically at the exit 6'. Further, a heater may be attached around the inlet side of the spindle holder 15' to heat the hose to be supplied. The inlet of the resin extruder crosshead 7 has an inner diameter larger than the outer diameter of the outer rubber layer and is not provided with a vacuum packing. Moreover, between the outlet of the rubber extruder crosshead 3 and the inlet of the resin extruder crosshead 7, a cylindrical connecting pipe (outer diameter 100 to 300 mm, length 30 cm to 5 m) with a diameter larger than the outer rubber layer of the hose is installed. 1
3 is connected, and its interior is communicated with the hose passage 17' of the crosshead 7 of the resin extruder. The connecting pipe 13 is provided with a suction port 24, and the inside thereof and the hose passage 17' of the resin extruder crosshead 7 communicating therewith can be evacuated. Further, the connecting pipe 13 is provided with a see-through window, so that the outer diameter of the outer rubber layer of the hose passing through the interior can be optically measured. Furthermore, the connecting pipe 13 and the resin extruder crosshead 7
A cooling device 25 is provided between the connecting pipes 13 and 25 to dissipate heat from the crosshead 7 of the resin extruder, which becomes hot, to prevent the connecting pipe 13 from being heated. Next, using this apparatus, the rubber hose shown in FIG. 3 was manufactured as follows. That is, as usual, an unvulcanized inner rubber layer 31 was continuously extruded around the outer periphery of the mandrel 30, a fiber reinforced layer 32 was formed around the outer periphery of the inner rubber layer 31 using a braiding machine, and the material was once wound around a drum. . Next, this hose is sent out from the feeder 1 as shown in Fig. 1, and the vacuum level is set to 320~320 at the suction port 20.
An unvulcanized outer rubber layer 33 was extruded around the outer periphery of the fiber-reinforced layer 32 using a rubber extruder crosshead 3 whose pressure was reduced to 600 mmHg. This hose has suction port 2
Connecting pipe 13 with reduced pressure to 200 to 400 mmHg in step 4
The resin was sent to the resin extruder crosshead 7 under the same reduced pressure condition, and a resin coating layer 34 was formed on the outer periphery of the outer rubber layer 33 by extrusion molding polymethylpentene at 250 to 280°C. Thereafter, this hose was passed through a cooling water tank 8, wound up with a winder 10, and vulcanized in a vulcanizer at 160° C. for 60 minutes. By vulcanization, a portion of the inner rubber layer 31 bulged out to the outer rubber layer 33 to form a hardened bulging convex portion 35, and both layers were firmly adhered. Finally, the resin coating layer 34 is removed using a resin peeling machine.
was removed, and the mandrel 30 was extracted by applying water pressure. Table 1 below summarizes the materials and outer diameters from the inner rubber layer to the resin coating layer.

[Table] For each sample obtained, the adhesive strength between the fiber reinforced layer and the outer rubber layer was measured, and the appearance of the outer rubber layer was observed. For comparison, the adhesion strength and appearance of rubber hoses made of the same material and manufactured under the same conditions except that a conventional device without a connecting pipe was used was also measured and the appearance was observed. The obtained results are shown in Table 2 together with the lead time from the formation of the outer rubber layer to the formation of the resin coating layer.

[Table] Instead of the fiber reinforcing layer 32 of the above embodiment, a metal reinforcing layer 36 made of two layers of braided metal wires is used,
Same as above except for vulcanizing at 150℃ for 60 minutes.
A rubber hose shown in FIG. 5 was manufactured. The material and outer diameter of this rubber hose are shown in Table 3, and the adhesive force, lead time, etc. measured in the same manner as in the above example are compared with a rubber hose manufactured under the same conditions except using a conventional device without a connecting pipe. It is shown in Table 4.

【table】

〔Effect of the invention〕

According to the present invention, a rubber hose whose inner circumferential surface and outer circumferential surface are vulcanized while restrained by a mandrel and a resin coating layer, respectively, is produced in an excellent appearance with no scratches on the surface and with high productivity. be able to.

[Brief explanation of drawings]

FIG. 1 is a schematic side view showing a specific example of the device of the present invention, and FIG. 2 is a sectional view of the main parts thereof.
FIG. 3 is a partial sectional view of a rubber hose having a fiber reinforced layer manufactured by the method of the present invention, and FIG. 4 is a schematic side view of a conventional device. FIG. 5 is a partial sectional view of a rubber hose having a metal reinforcing layer manufactured by the method of the present invention. 1... Feeding machine, 2... Rubber extruder, 3... Rubber extruder crosshead, 4, 8... Cooling water tank, 6...
...Resin extruder, 7...Resin extruder crosshead,
10... Winder, 11, 12, 20, 24... Suction port, 13... Connecting pipe, 14, 14'... Crosshead body, 15, 15'... Spindle holder, 16, 16'... Spindle , 17, 17'...
...Hose passage, 19...Vacuum packing, 21...
...Rubber supply path, 22, 22'...Dice, 23...
...resin supply path, 25 ... cooling device, 30 ... mandrel, 31 ... inner rubber layer, 32 ... fiber reinforcement layer, 33 ... outer rubber layer, 34 ... resin coating layer,
35...Bulging convex portion, 36...Metal reinforcing layer.

Claims (1)

[Claims] 1. An inner rubber layer is formed on the outer periphery of the mandrel, a reinforcing layer is formed on the outer periphery of the inner rubber layer, an outer rubber layer is extruded on the outer periphery of the reinforcing layer, and then an outer rubber layer is formed on the outer periphery of the outer rubber layer. In a method of manufacturing a rubber hose in which a resin coating layer is extruded, vulcanized, and then the resin coating layer is removed, the steps from extrusion molding of the outer rubber layer to extrusion molding of the resin coating layer are continuously performed in a reduced pressure atmosphere. A method for manufacturing a rubber hose, characterized by: 2. A rubber extruder crosshead attached to a rubber extruder that extrudes an outer rubber layer on the outer periphery of a reinforcing layer applied to the outer periphery of the inner rubber layer, and a resin coating on the outer periphery of the outer rubber layer extruded from the outlet of the rubber extruder crosshead. A resin extruder crosshead attached to a resin extruder for extruding the layer and having an inlet having a larger diameter than the outer rubber layer, and an outer rubber layer connecting between the outlet of the rubber extruder crosshead and the inlet of the resin extruder crosshead. A rubber hose manufacturing device comprising a connecting pipe having a larger diameter and a cylindrical shape, and a suction port provided in the connecting pipe and capable of suctioning and exhausting the inside of the connecting pipe and the inside of the hose passage of the resin extruder crosshead to a reduced pressure state. . 3. The rubber hose manufacturing apparatus according to claim 2, further comprising a cooling device between the connecting pipe and the crosshead of the resin extruder.