JP2009113268A - Rubber coating method, manufacturing method of rubber hose, and molding apparatus of coated rubber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a rubber hose which forms the outside unvulcanized rubber by the cross head method while forming a small diameter part on the end of the rubber hose. <P>SOLUTION: On the circumference of a mandrel 12, an inner unvulcanized rubber 15 and the reinforcing cord layers 4a, 4b, 4c and 4d are formed, and small diameter parts 6 are formed on both the end parts. The mandrel 12 is passed through the cross head 8 to extrude an unvulcanized rubber tube 9. The inner diameter of the rubber bag 14 is reduced to press/attach the unvulcanized rubber tube 9 to the small diameter part 6 of the front end side. While the mandrel 12 is moved, the unvulcanized rubber tube 9 is extruded to form the outer unvulcanized rubber. By reducing the diameter of the rubber bag 14, the unvulcanized rubber tube 9 is pressed/attached to the small diameter part 6 of the back end part. The inner unvulcanized rubber 15 and the outer unvulcanized rubber 16 are subjected to vulcanization molding. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a rubber coating method for forming outer surface unvulcanized rubber by, for example, a crosshead method, a method for manufacturing a rubber hose, and a molding apparatus for coated rubber.

  Generally, a rubber hose such as a pumping tube equipped in a squeeze pump has a structure in which an outer peripheral surface of an inner surface rubber and a reinforcing layer are covered with an outer surface rubber, and forms an outer surface unvulcanized rubber of an unvulcanized rubber molded body. As a method, a crosshead method is often employed (for example, Patent Document 1).

In order to form the outer unvulcanized rubber by the conventional crosshead method, it is formed around the mandrel by pushing the unvulcanized rubber into the crosshead through which the mandrel passes while moving the mandrel in the central axis direction. The unvulcanized rubber is continuously coated so as to be rubbed on the outer peripheral side of the inner unvulcanized rubber and the reinforcing layer. In addition, when the diameter of the rubber hose is larger than a certain size, a cylindrical spindle is mounted on the cross head together with a die for regulating the outer diameter of the unvulcanized rubber molded body, and the inner surface is not connected between the die and the spindle. Unvulcanized rubber is extruded and coated on the entire outer circumference of the vulcanized rubber and the reinforcing layer to form an outer unvulcanized rubber.
JP 2000-280322 A

  However, in the above crosshead system, the outer diameter of the unvulcanized rubber molded body is regulated by a die, so the cross-sectional shape of the unvulcanized rubber molded body must be the same shape over the entire length of the hose body part. Moreover, it is necessary to set the unvulcanized rubber molded body to a size that can pass through a die. Therefore, different diameters such as molding an unvulcanized rubber molded body while forming a small diameter part at the end, or molding an unvulcanized rubber molded body while fixing a large diameter fitting to the end part. When molding an unvulcanized rubber molded body of a rubber hose having a portion, it is difficult to adopt a crosshead method as a method of forming the outer surface unvulcanized rubber.

  The present invention can form the outer surface unvulcanized rubber of the rubber hose having a different diameter portion by a crosshead method or the like, in particular, forming the outer surface unvulcanized rubber of the rubber hose having a small diameter portion at the end. An object of the present invention is to provide a rubber covering method, a rubber hose manufacturing method, and a covering rubber molding apparatus.

  In order to achieve the above object, the rubber coating method according to the present invention first passes the mandrel and the inner material arranged around the mandrel through the head of the extruder, and the unvulcanized rubber tube is inserted between the die and spindle of the head. Extrude. After crimping the front end portion of the unvulcanized rubber tube to the outer peripheral side of the front end portion of the inner material, the mandrel is moved in the direction of the central axis while pushing the unvulcanized rubber tube, so that the inner material is made of the unvulcanized rubber tube. The unvulcanized rubber tube is further crimped to the outer peripheral side of the rear end portion of the inner material.

  According to the above configuration, the unvulcanized rubber tube is once extruded from between the die and the spindle, and the inner material is covered with the unvulcanized rubber tube, so that the outer diameter can be covered with the die without restricting the outer diameter. And the die diameter can be set sufficiently larger than the outer diameter of the inner material after rubber coating. As a result, for example, a cross head method can be adopted, and the inner material whose diameter changes along the central axis direction can be covered with rubber, and the inner member can be covered with rubber while fixing a large-diameter fitting. For example, it is possible to facilitate the rubber coating of the inner member having the different diameter portion. Here, the internal arrangement around the mandrel can be exemplified by the uncured rubber on the inner surface of the rubber hose and the reinforcing layer before being coated with the uncured rubber on the outer surface, and further the one integrated with the mandrel, that is, the mandrel itself. May be.

  In addition, the outer peripheral side of the central part of the inner material is covered with an unvulcanized rubber tube without crimping from the outside, but by setting the moving speed of the mandrel faster than the extrusion speed of the unvulcanized rubber tube, Since the vulcanized rubber tube is pulled in the tube length direction to reduce the diameter, the unvulcanized rubber tube can be adhered to the inner material.

  Further, as a technique for more firmly attaching the unvulcanized rubber tube to the inner material, vacuum suction is performed on the rear side in the moving direction of the mandrel from the extrusion port of the unvulcanized rubber tube, and / or Alternatively, the unvulcanized rubber tube can be brought into close contact with the inner material by spraying air on the front side in the moving direction of the mandrel.

  If the end of the inner material is a small diameter part smaller than the center part, the end part can be covered with rubber, and the unvulcanized rubber tube can be stopped by crimping to the end of the inner material. The wearing power can be increased.

  Furthermore, even when the rear end portion of the inner material is a small diameter portion, when the rear end portion of the inner material is covered with the unvulcanized rubber tube, the uncured rubber tube is reduced in diameter by increasing the moving speed of the mandrel. It is possible to prevent the unvulcanized rubber tube from becoming wrinkles.

  That is, when the rear end portion of the inner material is a small-diameter portion, the unvulcanized rubber tube is easily lifted from the outer peripheral surface of the inner material when the coating with the unvulcanized rubber tube reaches the rear end portion from the central portion. Due to this lifting, the unvulcanized rubber tube may become wrinkles when crimped from the outside, but by increasing the moving speed of the mandrel, the unvulcanized rubber tube can be reduced in diameter, It is possible to prevent the unvulcanized rubber tube from floating up.

  The present invention also provides a method for producing a rubber hose by coating the inner surface unvulcanized rubber as the inner material and the outer peripheral side of the reinforcing layer with the outer surface unvulcanized rubber. This rubber hose manufacturing method forms the outer unvulcanized rubber by the same method as the above rubber coating method, and the same effect as the above rubber coating method can be obtained.

  That is, according to the present invention, an inner unvulcanized rubber and a reinforcing layer are sequentially formed around a mandrel, and then the mandrel is passed through the head of an extruder, and an unvulcanized rubber tube is inserted between a die and a spindle of the head. After extruding and crimping the front end portion of the unvulcanized rubber tube to the inner surface unvulcanized rubber and the outer peripheral side of the front end portion of the reinforcing layer, the mandrel is moved forward in the central axis direction while extruding the unvulcanized rubber tube. By covering the outer peripheral side of the inner unvulcanized rubber and the reinforcing layer with the unvulcanized rubber tube, the unvulcanized rubber tube is further crimped to the outer peripheral side of the rear end portion of the inner unvulcanized rubber and the reinforcing layer. The unvulcanized rubber tube covering the inner surface unvulcanized rubber and the reinforcing layer is used as an outer surface unvulcanized rubber, and then the inner surface unvulcanized rubber and the outer surface unvulcanized rubber are vulcanized and molded. To provide a method of manufacturing a rubber hose to.

  The present invention also includes an extruder, a head attached to the extruder, a die and a spindle that are attached to the head to push out an unvulcanized rubber tube, a mandrel that passes through the die and the spindle, and the mandrel A moving device that moves the mandrel in the direction of the central axis so that the outer peripheral side of the inner material arranged around is covered with the unvulcanized rubber tube, and the mandrel in the mandrel moving direction in front of the extrusion port of the unvulcanized rubber tube And a ring-shaped rubber bag that surrounds the outer peripheral side from the outer peripheral side.

  The rubber bag of this coated rubber molding device allows the inner diameter of the ring shape to be increased and decreased by adjusting the internal pressure, and the unvulcanized rubber tube is crimped to the outer peripheral side of the inner material by reducing the inner diameter. Then, the mandrel is allowed to move by expanding the inner diameter.

  As a result, when the rubber coating of the inner material is started and when the rubber coating is completed, the unvulcanized rubber tube is crimped to the outer peripheral side of the end of the inner material with a rubber bag, and the mandrel is moved while pushing the unvulcanized rubber tube. When the central portion of the material is covered with rubber, the central portion of the inner material can be passed through the rubber bag without hindering the movement of the mandrel. In addition, since a rubber bag is used for crimping the unvulcanized rubber tube, it is possible to easily crimp the unvulcanized rubber tube to a portion where the diameter of the inner material changes, such as a small diameter portion formed at the end of the inner material. Can do.

  By increasing the internal pressure of the ring-shaped rubber bag and reducing the diameter, the inner portion of the ring shape may be compressed in the circumferential direction to become wrinkles. If the tube is set to be smaller than the inner diameter when crimping to the outer peripheral side of the inner material, the rubber bag can be prevented from becoming wrinkles and the unvulcanized rubber tube can be uniformly crimped. When the unvulcanized rubber tube is pressure-bonded, the reduced diameter is regulated by the reaction force, so that the internal pressure of the rubber bag can be sufficiently increased. Moreover, what is necessary is just to make an internal pressure lower than atmospheric pressure in order to expand a rubber bag diameter.

  As described above, according to the present invention, the unvulcanized rubber is once extruded from the die and the spindle as an unvulcanized rubber tube, and the inner material such as the inner surface unvulcanized rubber and the reinforcing layer is covered with the unvulcanized rubber tube. Therefore, the die diameter can be set sufficiently larger than the inner diameter after rubber coating, that is, the outer diameter of the unvulcanized rubber molding. In addition, the ring-shaped rubber bag can reduce the inner diameter and crimp the unvulcanized rubber tube to the inner material, while expanding the inner diameter and allow the center portion and the fitting to pass through.

  This makes it possible to easily cover the inner material with a different diameter part while adopting a crosshead method, etc., so it is easy to use a rubber hose with a small diameter end or a large diameter fitting. Can be manufactured.

  The best mode for carrying out a rubber coating method, a rubber hose manufacturing method, and a coated rubber molding apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 is a view showing a rubber hose manufactured by the method according to the present invention, wherein (a) is a cross-sectional view of the upper half, (b) is a side view, and (b) is an enlarged cross-sectional view of the main part of (a). . In FIG. 1A, in the side view of the lower half, the outer rubber and a part of the reinforcing cord layer are sequentially peeled to show the inside.

  The rubber hose 1 manufactured by the method according to the present invention has a relatively medium diameter, and four reinforcing cord layers 4a, 4b, 4c, 4d are interposed between the inner rubber 2 and the outer rubber 3, and its end An enlarged diameter portion 5 having an inner diameter larger than that of the central portion is formed for attaching a fitting to the portion, and a small diameter in which the outer diameter is set to a smaller diameter toward the outer end at the further end portion of the enlarged diameter portion 5. Part 6 is formed.

  The reinforcing cord layers 4a, 4b, 4c, and 4d are, for example, steel cord layers formed by arranging a plurality of steel cords in the bias direction, and each layer is continuously provided by being folded at the end of the rubber hose 1. Yes. The folded portions of the reinforcing cord layers 4a, 4b, 4c, and 4d are provided at positions slightly inside from the end face of the rubber hose 1, and are sealed without being exposed from the end face of the rubber hose 1.

  Next, a method for manufacturing a rubber hose will be described. FIG. 2 is a sectional view of a molding apparatus used in the method according to the present invention. In FIG. 2, the mandrel shows a side view. FIG. 3 is a cross-sectional view of the rubber bag, in which (a) shows a free state, (b) shows an expanded state, and (c) shows a reduced state. FIG. 4 is a cross-sectional view showing a process of forming the outer unvulcanized rubber with a molding apparatus.

  First, the configuration of a molding apparatus for molding the outer surface unvulcanized rubber will be described.

  The molding apparatus 7 includes an extruder for extruding unvulcanized rubber, a crosshead 8 attached to the tip of the extruder, a die 10 and a spindle 11 that are attached to the crosshead 8 and extrude an unvulcanized rubber tube 9; A mandrel 12 disposed so as to pass through the crosshead 8, the die 10 and the spindle 11, a moving device 13 for moving the mandrel 12 in the central axis direction, and a mandrel 12 provided on the front side of the crosshead 8 on the outer peripheral side And a ring-shaped rubber bag 14 that surrounds.

  The molding device 7 includes a rubber bag 14 and an end portion of the unvulcanized rubber tube 9 on the outer peripheral side of the end portions of the inner surface unvulcanized rubber 15 and the reinforcing cord layers 4a, 4b, 4c, and 4d formed around the mandrel 12. And the mandrel 12 is moved while extruding the unvulcanized rubber tube 9, and the outer peripheral side of the inner surface unvulcanized rubber 15 and the reinforcing cord layers 4a, 4b, 4c, 4d is covered with the unvulcanized rubber tube 9 Thus, the unvulcanized rubber molded body 17 is molded by using the outer surface unvulcanized rubber 16.

  The crosshead 8 has a through-hole through which the mandrel 12 passes, and is large enough to pass through an unvulcanized rubber molded body 17 molded around the mandrel 12 on the front side and rear side of the crosshead 8. A die 10 and a spindle 11 having an inner diameter of 1 mm are mounted.

  The die 10 and the spindle 11 are formed with a cylindrical portion 10a and a cylindrical portion 11a that are inserted into the through holes from the front side and the rear side of the cross head 8, respectively. Among these, the outer diameter of the cylindrical portion 10 a of the die 10 is set to a size that fits in the through hole of the cross head 8 without a gap, and the outer diameter of the cylindrical portion 11 a of the spindle 11 is larger than that of the through hole of the cross head 8. Is set too small.

  The space between the outer peripheral surface of the cylindrical portion 11a and the inner peripheral surface of the through hole is a rubber flow path 18 through which unvulcanized rubber is pushed out from the extruder. The vulcanized rubber is extruded into the inside of the die 10 as an unvulcanized rubber tube 9 from an extrusion port 19 formed by forming an annular gap over the entire circumference between the cylindrical portion 10a and the cylindrical portion 11a.

  Further, the cylindrical portion 10a of the die 10 and the cylindrical portion 11a of the spindle 11 are set to have a length that the rear end portion and the front end portion wrap in the central axis direction of the mandrel 12, and avoid interference between the wrap portions. Thus, a taper is formed on the inner peripheral side of the rear end portion of the cylindrical portion 10a and the outer peripheral side of the front end portion of the cylindrical portion 11a. The gap between the tapers is the aforementioned extrusion port 19, and the unvulcanized rubber tube 9 is pushed out inside and forward of the die 10. In FIGS. 1 and 4, reference numeral 20 denotes an adjustment ring for spreading the unvulcanized rubber extruded into the rubber flow path 18 over the entire circumference of the rubber flow path 18.

  The moving device 13 is, for example, a rail 21 arranged in parallel with the mandrel 12, a pair of support bases 22 that are provided movably along the rail 21 and support both ends of the mandrel 12, and moves the support base 22. It is comprised from the support stand moving parts 23, such as a cylinder. The moving device 13 may have any configuration as long as it moves the mandrel 12 in the central axis direction.

  The rubber bag 14 is attached to the front side of the die 10 via a mounting bracket 24. By adjusting the internal pressure with a compressor or the like (not shown), the inner diameter of the ring shape is made smaller than that in the free state shown in FIG. Within a large diameter range, as shown in FIGS. 3B and 3C, the diameter can be increased and decreased. As shown in FIG. 3 (b), the rubber bag 14 allows the mandrel 12 to move by expanding the inner diameter, and as shown in FIG. 3 (c), the rubber bag 14 is not added by reducing the inner diameter. The vulcanized rubber tube 9 is pressure-bonded to the inner peripheral unvulcanized rubber 15 and the outer peripheral side of the end portions of the reinforcing cord layers 4a, 4b, 4c and 4d.

  In addition, the rubber bag 14 has an inner diameter in the free state shown in FIG. 3 (a) set smaller than the inner diameter at the time of reduction shown in FIG. The rubber bag 14 is prevented from becoming wrinkles when crimped to the outer peripheral side of the vulcanized rubber 15 and the reinforcing cord layers 4a, 4b, 4c, and 4d.

  The procedure for molding the unvulcanized rubber molded body 17 using the molding apparatus 7 will be specifically described. First, the inner unvulcanized rubber 15 and the reinforcing cord layers 4a, 4b, 4c, and 4d are disposed around the mandrel 12. Sequentially formed. At this time, both end portions of the inner unvulcanized rubber 15 and the reinforcing cord layers 4a, 4b, 4c, and 4d are formed to have a smaller diameter than the central portion and a smaller diameter toward the outer end side to form the small diameter portion 6.

  Here, the rubber hose 1 to be manufactured has, for example, a small diameter portion 6 having a total length of 1250 mm, an inner diameter of φ38.1 mm, an outer diameter (D) of φ63 mm, an outer rubber 3 having a thickness (t) of 2 mm, and covered with the outer rubber 3. Is 4 mm, the length (a) of the small-diameter portion 6 is 25 mm, the total thickness of the reinforcing cord layers 4a, 4b, 4c, and 4d is 4 mm, and the outer diameter of the outermost layer 4d is φ59 mm.

  Next, as shown in FIG. 4A, the rubber bag 14 is expanded to an inner diameter (for example, φ70 mm) that allows the mandrel 12 to move by reducing the internal pressure by suction (for example, an air pressure of 200 mmHG or less). Let Further, the mandrel 12 is passed through the cross head 8 and the unvulcanized rubber tube 9 is pushed out from the extrusion port 19 between the die 10 and the spindle 11.

  For example, the unvulcanized rubber tube 9 has a diameter of 64 mm for the tip of the spindle 11 and a diameter of 70 mm for the die 10 and a width of the extrusion port 19 measured in a direction perpendicular to the taper of 2 mm. The inner diameter at the tip of the rubber rubber tube 9 is 55 mm. The inner diameter of the unvulcanized rubber tube 9 is slightly larger than the outer diameter (for example, φ51 mm) of the inner diameter unvulcanized rubber 15 and the small diameter portion 6 of the reinforcing cord layers 4a, 4b, 4c, and 4d.

  As shown in FIG. 4B, the front end portions of the inner unvulcanized rubber 15 and the reinforcing cord layers 4a, 4b, 4c, and 4d and the front end portion of the unvulcanized rubber tube 9 are positioned inside the rubber bag 14. Let Further, the extrusion of the unvulcanized rubber tube 9 and the movement of the mandrel 12 are stopped, the internal pressure of the rubber bag 14 is increased (for example, air pressure of 0.05 MPa), and the inner diameter of the ring shape is reduced (for example, φ55 mm). Thus, the front end portion of the unvulcanized rubber tube 9 is pressure-bonded to the outer peripheral side of the inner diameter unvulcanized rubber 15 and the small diameter portion 6 which is the front end portion of the reinforcing cord layers 4a, 4b, 4c, and 4d. The rubber bag 14 has a free state inner diameter (for example, φ52 mm) set smaller than that at the time of the reduced diameter (for example, φ55 mm), so that the reduced diameter does not cause wrinkles.

  As shown in FIG. 4 (c), after expanding the inner diameter of the rubber bag 14, the mandrel 12 is pushed forward in the central axis direction while pushing out the unvulcanized rubber tube 9, for example, about 1 (m / min). Move at a speed of. By setting the moving speed of the mandrel 12 faster than the extrusion speed of the unvulcanized rubber tube 9, the unvulcanized rubber tube 9 is contracted by pulling it in the tube length direction with a pulling rate of, for example, about 50%. The diameter is made to adhere to the inner unvulcanized rubber 15 and the reinforcing cord layers 4a, 4b, 4c, and 4d. Thereby, the outer peripheral side of the inner surface unvulcanized rubber 15 and the reinforcing cord layers 4a, 4b, 4c, and 4d is covered with the unvulcanized rubber tube 9.

  Here, the tensile rate when the unvulcanized rubber tube 9 is pulled, that is, the ratio of the elongation amount to the original length is preferably 20% to 100%, more preferably 30% to 60%. Is preferred. If the pulling rate is too large, the rubber becomes thin, and if it is too small, the unvulcanized rubber tube 9 may become wrinkled and cause problems such as air entry. The pulling rate of the unvulcanized rubber tube 9 is preferably set larger as the tube thickness is thinner.

  Further, in the crosshead 8, vacuum suction is performed on the rear side in the movement direction of the mandrel 12 from the extrusion port 19 of the unvulcanized rubber tube 9, and air is sprayed on the front side in the movement direction of the mandrel 12, thereby The vulcanized rubber tube 9 can be brought into close contact with the inner unvulcanized rubber 15 and the reinforcing cord layers 4a, 4b, 4c and 4d.

  Further, when the inner diameter unvulcanized rubber 15 and the small diameter portion 6 which is the rear end portion of the reinforcing cord layers 4a, 4b, 4c and 4d are covered with the unvulcanized rubber tube 9, the moving speed of the mandrel 12 is made faster. Thus, the diameter of the unvulcanized rubber tube 9 is reduced to be smaller and is brought into close contact with the small diameter portion 6.

  As shown in FIG. 4D, after the inner diameter unvulcanized rubber 15 and the small diameter portion 6 on the rear end side of the reinforcing cord layers 4a, 4b, 4c, and 4d are covered with an unvulcanized rubber tube 9, the rubber When positioned inside the bag 14, the unvulcanized rubber tube 9 is not pushed out and the mandrel 12 is stopped, the inner diameter of the rubber bag 14 is reduced, and the unvulcanized rubber tube 9 is crimped to the outer peripheral side of the small diameter portion 6. To do.

  Furthermore, after expanding the diameter of the rubber bag 14, the unvulcanized rubber tube 9 behind the crimping portion on the rear end side is separated by moving the mandrel 12 while stopping the extrusion of the unvulcanized rubber tube 9. . Thus, the entire inner unvulcanized rubber 15 and the reinforcing cord layers 4a, 4b, 4c, and 4d are covered with the unvulcanized rubber tube 9, and the unvulcanized rubber tube 9 is used as the outer unvulcanized rubber 16. The unvulcanized rubber molded body 17 is molded.

  Then, the rubber hose 1 is obtained by carrying out the vulcanization molding of the inner surface unvulcanized rubber 15 and the outer surface unvulcanized rubber 16 of the unvulcanized rubber molded body 17.

  According to the above configuration, the unvulcanized rubber tube 9 is once pushed out, and then the end portion thereof is pressure-bonded with the rubber bag 14 so that the inner unvulcanized rubber 15 and the reinforcing cord layers 4a, 4b, 4c, and 4d are bonded. Since it coats, the small diameter part 6 can also be coat | covered with the outer surface unvulcanized rubber 16, adopting a crosshead system.

  Thereby, even if it is the rubber hose 1 which has the small diameter part 6 in an edge part, when forming the outer surface unvulcanized rubber 16, the level difference like a sheet winding system does not arise, the surface is smooth, and the outside dimension is constant. For example, the dimensional accuracy of the unvulcanized rubber molded body 17 can be increased, and mold vulcanization that requires high outer diameter accuracy is enabled. In addition, by adopting the crosshead method, high adhesion can be obtained by molding in a hot state, and long ones can be continuously molded.

  Here, as the rubber hose 1 having the small-diameter portion 6 at the end, a vibrator hose for applying vibration to and solidifying the ready-mixed concrete can be exemplified. The vibrator hose has a small-diameter portion 6 at its end so that it is possible to improve the workability by suppressing the catch when moving on the rebar and the like, and the smoothness of the surface is increased. It is also possible to suppress drag when dragging. Further, the rubber hose 1 can be suitably used as a pumping tube of a squeeze pump because the surface smoothness is increased, and the small diameter portion 6 can facilitate insertion into the pump case.

  In addition, since the start and completion of the coating with the unvulcanized rubber tube 9 is performed by pressure bonding with the rubber bag 14, only the movement / stop of the mandrel 12, the operation / stop of the extruder, and the pressure suction of the rubber bag are controlled. Thus, the formation of the outer surface unvulcanized rubber 16 can be easily automated. Thereby, the unvulcanized rubber moldings 17 of the plurality of rubber hoses 1 can be intermittently and repeatedly molded automatically.

  In addition, this invention is not limited to said embodiment, A change can be suitably added within the scope of the present invention. For example, instead of forming the small-diameter portion 6 at the end of the rubber hose 1 or forming the small-diameter portion 6, the unvulcanized rubber molded body 17 is molded while attaching a large-diameter fitting to the end. You can also. In the conventional crosshead method, since the die diameter is about the same size as the hose body part, it was not possible to pass a large diameter fitting, but in the method of the present invention, the die diameter is set sufficiently large Therefore, the outer surface unvulcanized rubber 16 can be formed by the crosshead method while fixing the large-diameter fitting.

  Moreover, as long as the outer peripheral side of the mandrel 12 is covered, it is not limited to the formation of the outer surface unvulcanized rubber 16 but can be used to form other things such as the formation of the inner surface unvulcanized rubber of the rubber hose.

It is a figure which shows the rubber hose manufactured by the method concerning this invention, (a) upper half is sectional drawing, lower half is side view, (b) is principal part expanded sectional view of (a). Sectional drawing of the molding apparatus used for the method according to the present invention It is sectional drawing of a rubber bag, (a) shows a free state, (b) shows a diameter-expanded state, (c) shows a diameter-reduced state. Sectional drawing which shows the process of forming an outer surface unvulcanized rubber with a molding device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rubber hose 2 Inner surface rubber 3 Outer surface rubber 4a, 4b, 4c, 4d Reinforcement cord layer 6 Small diameter part 7 Molding device 8 Crosshead 9 Unvulcanized rubber tube 10 Die 11 Spindle 11a Tube part 12 Mandrel 13 Moving device 14 Rubber bag 15 Inner surface Unvulcanized rubber 16 Outer surface unvulcanized rubber 17 Unvulcanized rubber molding 19 Extrusion port

Claims (5)

  The mandrel and the inner material arranged around it are passed through the head of the extruder, the unvulcanized rubber tube is extruded from between the die and spindle of the head, and the front end of the unvulcanized rubber tube is the outer periphery of the front end of the inner material. After pressing the unvulcanized rubber tube, the mandrel is moved in the direction of the central axis while extruding the unvulcanized rubber tube to cover the outer peripheral side of the inner material with the unvulcanized rubber tube. A rubber coating method comprising pressing a rubber tube on the outer peripheral side of a rear end portion of an inner material.   By setting the moving speed of the mandrel faster than the extrusion speed of the unvulcanized rubber tube, the unvulcanized rubber tube is pulled in the tube length direction to reduce the diameter so as to be in close contact with the inner material. The rubber coating method according to claim 1.   The rubber coating method according to claim 1, wherein an end portion of the inner material is a small-diameter portion having a smaller diameter than a central portion.   An inner unvulcanized rubber and a reinforcing layer are sequentially formed around the mandrel, and then the mandrel is passed through the head of the extruder, and an unvulcanized rubber tube is extruded from between the die and the spindle of the head, and the unvulcanized After the front end portion of the rubber tube is pressure-bonded to the inner surface of the unvulcanized rubber and the outer peripheral side of the front end portion of the reinforcing layer, the unvulcanized rubber tube is pushed forward to move the mandrel forward in the central axis direction. Cover the outer peripheral side of the inner unvulcanized rubber and the reinforcing layer with a vulcanized rubber tube, and further press-bond the unvulcanized rubber tube to the outer peripheral side of the rear end portion of the inner unvulcanized rubber and the reinforcing layer. The unvulcanized rubber tube for covering the vulcanized rubber and the reinforcing layer is formed as an outer uncured rubber, and then the inner uncured rubber and the outer unvulcanized rubber are vulcanized and molded. Method. An extruder, a head attached to the extruder, a die and a spindle attached to the head to extrude an unvulcanized rubber tube, a mandrel passing through the die and the spindle, and disposed around the mandrel A moving device for moving the mandrel in the direction of its central axis so that the outer peripheral side of the inner material is covered with an unvulcanized rubber tube, and the mandrel on the outer peripheral side in front of the unvulcanized rubber tube extrusion port in the direction of movement of the mandrel With a ring-shaped rubber bag that surrounds
In the rubber bag, the inner diameter of the ring shape can be increased and decreased by adjusting the internal pressure, and the unvulcanized rubber tube is crimped to the outer peripheral side of the inner material by reducing the inner diameter. An apparatus for molding a coated rubber, wherein the mandrel is allowed to move by expanding the diameter.

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