JP2006056110A - Method for producing cylindrical rubber molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a cylindrical rubber molding in which a reinforcing cord layer can be formed at a low cost by using the same production apparatus irrespective of an outside diameter, a cord interval is wide in a large diameter part in the molding having a different diameter part, and the cord interval is narrow in a small diameter part. <P>SOLUTION: The method for producing the cylindrical rubber molding has the first unvulcanized rubber layer forming process in which a first unvulcanized rubber composition forming an inside rubber layer is laminated, a reinforcing cord layer forming process in which at least two layers are supplied spirally to constitute a reinforcing cord layer of a bias structure while a turnover part is formed at the end part of the belt of topping cords, the second unvulcanized rubber layer forming process for forming an outside rubber layer, and a vulcanization process. In the reinforcing cord layer forming process, a cord interval adjusting device is used, and the belt is supplied with the cord interval widened in the large diameter part and with the cord interval narrowed in the small diameter part. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a flexible cylindrical rubber molded body having a relatively high pressure resistance, such as a rubber hose, an air roller, an air spring, and a flexible joint having a different diameter portion and a reinforcing cord layer.

Fiber reinforcing layers in cylindrical rubber molded bodies such as hoses and flexible pipes, which are laminated with rubber and reinforcing cords in a cylindrical shape, are usually interlaced cords in an unvulcanized rubber composition. After the topping, a sheet-like topping cord is produced by bias cutting so that the reinforcing cord is inclined by 40 to 60 ° with respect to the longitudinal axis. The sheet-like topping cord is formed in two or four layers in two opposite directions. Are formed as a bias code layer (Patent Document 1, etc.).
JP-A-6-210798

  However, according to the technique described in Patent Document 1, the formed fiber reinforcement layer is usually formed by affixing a topping cord in a cold state, so that the adhesive strength at the time of lamination is weak, and an interdigital wide cord is formed. Since multiple sheets are made from continuous sheets by cutting and pasted alternately, material loss occurs at the time of cutting, yield is low, and a cutting process is required, which increases man-hours. There was a problem that the production cost increased.

  Further, as shown in FIG. 8, in a flexible tube (FIG. 8 (a)) or a tapered flexible tube (FIG. 8 (b)) having a narrow central portion and a large outer diameter at both ends. In order to form the fiber reinforcement layer, it is necessary to widen the cord interval in the large diameter portion, and conventionally, the worker has manually formed the fiber reinforcement layer. It was difficult to eliminate the non-uniformity between connected cords.

  An object of the present invention is to produce a cylindrical rubber molded body in which a uniform reinforcing cord layer is formed in which a cord interval is wide at a large diameter portion and a cord interval is narrow at a small diameter portion in a cylindrical rubber molded body having different diameter portions. A method is provided.

The present invention is a method for producing a cylindrical rubber molded body having different diameter portions provided with an inner rubber layer, a reinforcing cord layer, and an outer rubber layer,
A first unvulcanized rubber layer forming step of laminating a first unvulcanized rubber composition for forming the inner rubber layer on the outer surface of a cylindrical mold, and a plurality of cords on the first unvulcanized rubber layer A reinforcing cord layer forming step of spirally winding a topping cord belt containing a plurality of layers so as to form a reinforcing cord layer of at least one bias structure, a second unvulcanized rubber composition forming an outer rubber layer A second unvulcanized rubber layer forming step for coating an unvulcanized cylindrical rubber molded body, and heating to vulcanize the unvulcanized cylindrical rubber molded body to obtain a cylindrical rubber molded body Has a sulfur process,
The reinforcing cord layer forming step is a step of supplying the topping cord belt in a state where the cord interval is wide in the large diameter portion using a cord interval adjusting device and supplying the cord interval in a state where the cord interval is narrow in the small diameter portion. It is characterized by that.

  With such a manufacturing method, the reinforcing cord layer can be formed at low cost using the same manufacturing apparatus regardless of the outer diameter of the cylindrical rubber molded body, and the cylindrical rubber molded body having a different diameter portion has a large diameter. It is possible to produce a cylindrical rubber molded body in which a uniform reinforcing cord layer is formed with a wide cord interval at the portion and a narrow cord interval at the small diameter portion. The “different diameter portion” means that there are portions having different outer diameters as illustrated in FIG. 8, for example, portions having different outer diameters due to formation of an arc shape, a tapered shape, or the like.

  When the cylindrical rubber molded body is provided with a fitting, a fitting arrangement step for arranging the fitting at a predetermined position is provided before the first unvulcanized rubber layer forming step.

  In the above method for producing a cylindrical rubber molded body, the cord interval adjusting device is preferably a roll set including at least one cord interval adjusting roll.

  With such a configuration, it is possible to form a uniform reinforcing cord layer having a wide cord interval in the large diameter portion and a narrow cord interval in the small diameter portion in the cylindrical rubber molded body having the different diameter portions.

  In the above method for producing a cylindrical rubber molded body, it is preferable that the cord interval adjusting roll is a rubber roll configured such that the cord interval can be adjusted by moving different diameter spacers in the axial direction.

  In the rubber roll having such a configuration, the cord interval of the belt of the topping cord can be easily adjusted by adjusting the position of the different diameter spacer.

  In the manufacturing method of the cylindrical rubber molded body described above, it is preferable that the cord interval adjusting device is a roll set including a belt feed width variable guide of at least one topping cord.

  By using the roll having such a configuration, the cord interval of the belt of the topping cord can be easily adjusted.

  As the cord constituting the reinforcing cord layer, a known cord used in the technical field such as a high-pressure rubber hose and a flexible tube can be used. Specific examples include polyester cords such as PET cords, polyamide cords such as nylon 6 and 6, aramid cords, steel cords, carbon fiber cords, and the like. These cords are used after performing an RFL treatment or the like for improving the adhesion to a rubber material as required. In the method for producing a cylindrical rubber molded body of the present invention, the use of a steel cord or an aramid cord is particularly preferable from the viewpoint of high strength and high reinforcement and easy adjustment of the cord interval. The reinforcing cord is topped with an unvulcanized rubber composition and used as a topping cord.

  As the rubber material constituting the unvulcanized rubber composition for topping the inner rubber layer, the outer rubber layer, and the cord, a known rubber material can be used. Generally, natural rubber, styrene butadiene rubber, polyisoprene rubber, polybutadiene rubber, polychloroprene rubber, ethylene propylene rubber, or the like can be used. These rubber materials are processed and used by a known method by adding a known compounding agent or additive. The inner rubber layer, the outer rubber layer, and the rubber material or unvulcanized rubber composition for topping the cord may have different compositions or the same composition. The same rubber material is preferably used from the viewpoint of obtaining high interlayer adhesion.

  FIG. 1 is a perspective view showing an embodiment in which a reinforcing cord layer of a tapered flexible tube having a fitting at each end is formed, and FIG. 2 is a plan view. A topping cord belt (hereinafter also simply referred to as a belt) 17 extruded from the extruder is mounted on a rotating shaft (not shown) through a cord interval adjusting device, and fittings 29 and 31 are arranged (fitting arrangement). Step), the first unvulcanized rubber composition layer 25 is formed (first unvulcanized rubber layer forming step) and supplied to the mandrel 27 and wound (reinforcing cord layer forming step). The belt can be wound by a combination of rotation of the mandrel and movement in the axial direction.

  In the example of FIGS. 1 and 2, the cord interval adjusting device is composed of three roll sets 11, 13, and 15. As the cord interval adjusting device, at least one of the rolls 11, 13, and 15 is a cord interval adjusting roll. All of the rolls 11, 13, and 15 may be cord spacing adjustment rolls. In the above example, the roll set also functions as a guide device that sends the belt 17 to a predetermined position.

  The topping cord belt 17 is supplied by the method illustrated in FIGS. That is, a cord unwound from a bobbin (not shown) is attached to a die 21 attached to the tip of the rubber extruder 19 via a number guide (not shown) set in accordance with a molded body to be molded. Supply. The unvulcanized rubber composition is topped in the die 21 and the topping cord belt 17 is pushed out.

  FIG. 6 is a front view illustrating a die for extruding the belt. The die 51 includes a cord 23 passage part and a slit part 53 for extruding only the unvulcanized rubber composition. By preparing and exchanging in accordance with the tubular body for forming the die having such a configuration, various tubular bodies can be easily produced using the same extruder.

In the reinforcing cord layer forming step, 3 to 6 belts are supplied together, and a plurality of belts are supplied without overlapping and without gaps. When the width of the belt 17 is W, the angle formed by the cord and the axis of the tubular body formed by the cord is θ, the number of belts to be supplied is n, and the outer diameter of the belt winding portion is L,
W = L · cos θ / n
And In the case of a tubular body having a different diameter portion, L varies depending on the position. Therefore, W is adjusted according to the variation of L by the cord interval adjusting device. θ is 40 to 60 °.

  FIG. 7 illustrates a reinforcing cord layer forming process in which three topping cord belts 17 (17a, 17b, 17c) are supplied to form a reinforcing cord layer. The belt is spirally provided on the fitting 29 and the first unvulcanized rubber layer, which is inserted into the mandrel 27, wound, and reaches the end to cover the fitting 29, for example, a steel cord. After the circumferential reinforcing member 60 is wound and fixed, the circumferential reinforcing member 60 is folded around the reversal axis and wound in the opposite direction. Such two reinforcing cord layers form a reinforcing cord layer having a bias structure.

  FIG. 3 is a cross-sectional view of a cord interval adjusting roll as a cord interval adjusting device. The cord interval adjusting roll 10 includes a rotating shaft 37, a rubber-like elastic body roll 33, and different diameter spacers 35a and 35b. The different diameter spacers 35a and 35b are externally fitted to the rotary shaft 37 and are configured to be able to enter and leave between the rubber-like elastic roll 33 and the rotary shaft 37, and the different diameter spacers 35a and 35b are retracted. Then, the rubber-like elastic body roll 33 is a flat roll when viewed from the direction parallel to the rotation axis, and the distance between the cords 23 of the topping cord belt is supplied from the die of the extruder (FIG. 3A). On the other hand, when the different-diameter spacers 35a and 35b enter between the rubber-like elastic body roll 33 and the rotating shaft 37, the outer diameter of the rubber-like elastic body roll 33 is enlarged and the central portion of the rubber-like elastic body roll 33 is The outer periphery is smaller than the end, and is concave when viewed from the direction parallel to the rotation axis. As a result, in the topping cord belt 17, the cord 23 approaches the central portion, and the cord interval is narrowed (FIG. 3B). Thus, the cord spacing can be adjusted by allowing the different diameter spacers 35 a and 35 b to enter and leave between the rubber-like elastic roll 33 and the rotating shaft 37.

  After the reinforcing cord layer is formed, a cylindrical rubber molded body is manufactured through a second unvulcanized rubber layer forming step and a vulcanizing step constituting the outer rubber layer.

  The thickness of the inner rubber layer and the thickness of the outer rubber layer are appropriately set according to the use and characteristics of the cylindrical rubber molded body, but the thickness of the inner rubber layer is generally 1 to 20 mm. The outer rubber layer generally has a thickness of 1 to 5 mm. The reinforcing cord layers are generally 1 to 4 layers as a pair of bias cord layers.

  FIG. 4 is a sectional view showing another embodiment of the cord interval adjusting device. The cord interval adjusting roll 50 includes a first roll 58 having a large-diameter portion 53 and a small-diameter portion 54 at the end of the rotary shaft 51, and a second roll 55 fitted to the small-diameter portion of the first roll. The topping cord belt 17 is guided through the recess between the step end surface 57 of the large diameter portion 53 of the roll 58 with the small diameter portion 54 and the end surface 56 of the second roll 55 facing the large diameter portion 53 of the first roll 58. pass. The first roll 58 and the second roll 55 are configured to be relatively close to each other and can be separated from each other, and the cord interval is narrowed by proximity and the cord interval is widened by separation.

  FIG. 5 is a perspective view showing another embodiment of a cord interval adjusting roll which is a cord interval adjusting device. The cord interval adjusting roll 44 uses a plurality of high-rigidity rods instead of the rubber-like elastic roll of the cord interval adjusting roll shown in FIG. That is, the cord interval adjusting roll 44 has a plurality of high-rigidity rods 41 fixed to the rotary shaft 43 at the center, and different diameter spacers 45a and 45b are fitted on the rotary shaft 43 so that both ends of the high-rigidity rod 41 are fitted. It is configured so as to be able to move in and out from the center toward the center. Similar to the cord interval adjusting roll of FIG. 3, the advancement of the different diameter spacers 45a and 45b toward the central portion causes the high-rigidity rod 41 to bend and expand its diameter, the cord interval adjusting roll 44 becomes concave, and the width of the belt 17 is increased. Narrows the code interval. The high-rigidity rod 41 is made of metal or resin.

The perspective view which showed embodiment which forms the reinforcement code | cord | chord layer of the taper-shaped flexible pipe which has a metal fitting at both ends, respectively The top view which showed embodiment which forms the reinforcement code | cord | chord layer of the taper-shaped flexible pipe which has a metal fitting at both ends, respectively Cross-sectional view illustrating a cord interval adjusting roll as a cord interval adjusting device Sectional drawing which showed another embodiment of the code | symbol space | interval adjustment apparatus The perspective view which showed another embodiment of the code space | interval adjustment roll Front view illustrating a topping cord belt extrusion die Illustration showing winding of topping cord belt Front view illustrating a cylindrical rubber molded body having a different diameter portion

Explanation of symbols

10 Cord spacing adjustment roll 17 Topping cord belt 33 Rubber elastic roll 35a, 35b Different diameter spacer 37 Rotating shaft

Claims (4)

A method for producing a cylindrical rubber molded body having different diameter portions provided with an inner rubber layer, a reinforcing cord layer, and an outer rubber layer,
A first unvulcanized rubber layer forming step of laminating a first unvulcanized rubber composition for forming the inner rubber layer on the outer surface of a cylindrical mold, and a plurality of cords on the first unvulcanized rubber layer A reinforcing cord layer forming step of spirally winding a topping cord belt containing a plurality of layers so as to form a reinforcing cord layer of at least one bias structure, a second unvulcanized rubber composition forming an outer rubber layer A second unvulcanized rubber layer forming step for coating an unvulcanized cylindrical rubber molded body, and heating to vulcanize the unvulcanized cylindrical rubber molded body to obtain a cylindrical rubber molded body Has a sulfur process,
The reinforcing cord layer forming step is a step of supplying the topping cord belt in a state where the cord interval is wide in the large diameter portion using a cord interval adjusting device and supplying the cord interval in a state where the cord interval is narrow in the small diameter portion. A method for producing a cylindrical rubber molded body characterized by the above.   The method for producing a cylindrical rubber molded body according to claim 1, wherein the cord interval adjusting device is a roll set including at least one cord interval adjusting roll.   3. The cylindrical rubber molded body according to claim 2, wherein the cord interval adjusting roll is a roll configured such that the cord interval can be adjusted by moving a different-diameter spacer in the axial direction. Production method.   The method for producing a cylindrical rubber molded body according to claim 2, wherein the cord interval adjusting roll is a roll set including at least one topping cord belt feed width variable guide roll.

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