JP2012224034A - Method of manufacturing belt for tire and pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a belt having high accuracy by preventing a positional shift on a winding roll or deformation or tendency in inner steel cord when winding a rubber strip having cord therein with edge cover rubber on the winding roll.SOLUTION: The method of manufacturing a belt for a tire includes: forming a rubber sheet s1 having cord therein by covering a reinforcement cord c with unvulcanized rubber; forming a rubber sheet piece s2 having cord therein by cutting the rubber sheet s1 having cord therein; forming a rubber strip s3 having cord therein by joining the rubber sheet piece s2 having cord therein with each other in a band shape with a linear cut edge as a side edge; extruding unvulcanized rubber q to the respective both side edges of the rubber strip s3 having cord therein to perform press bonding by calender rolls 12, 13; and forming a strip s4 with edge cover rubber by cutting excessive parts of the unvulcanized rubber so that the rubber strip s3 having cord therein to which the unvulcanized rubber is press bonded has a predetermined width.

Description

  The present invention relates to a method for manufacturing a tire belt and a pneumatic tire using the belt manufactured by this method.

  Pneumatic tires are provided with a belt layer made of rubber coated with multiple steel cords, but the belt layer has a cut end of the steel cord at the end, so the separation between the surrounding rubber and the steel cord There is a problem that it is easy to produce. For this reason, usually, the end portion of the belt layer is covered with an edge cover rubber member made of the same kind as the rubber covering the steel cord, or the end portion of the belt layer is wrapped with the edge cover rubber member. The occurrence of separation in the tire is suppressed, and the durability of the pneumatic tire is ensured (for example, see Patent Document 1).

  Conventionally, such a cover edge rubber member is formed at the time of forming the belt. Specifically, a plurality of steel cords are arranged in parallel at a predetermined interval and are not added to the steel cord. A corded rubber sheet is formed by covering with a vulcanized rubber, and then the corded sheet is cut linearly at a predetermined inclination angle with respect to the extending direction of the steel cord every predetermined length. After the sheet pieces are formed, and then the corded rubber sheet pieces are joined to each other in a belt shape with the straight cut edges as side edges, a corded rubber strip is formed, and then FIGS. As shown in FIG. 4, uncured using a calendar device (also referred to as a three-calendar) having three rolls 102, 103, 104 on the upper surface of each edge portion e1, e2 of the corded rubber strip s3. A narrow strip r 'made of rubber was attached. Alternatively, as shown in FIG. 7C, a similar narrow strip r ′ is placed on each edge portion e1, e2 of the corded rubber strip s3 and the end of the narrow strip r ′ is connected to the edge portion e1, The edge portions e1 and e2 may be wrapped around the back surface of e2. In any case, the narrow strip r 'flows to the periphery during vulcanization, and an edge cover rubber member is formed adjacent to the end of the belt layer.

JP 2008-6890 A

  By the way, a corded rubber strip formed by joining corded rubber sheet pieces is usually wound around a take-up roll and stored, and then is usually used after being drawn out from the take-up roll toward a belt forming drum. As shown in FIG. 8, when the corded rubber strip s4 having the narrow strip r ′ as described above is wound up to form a winding roll, the height of the narrow strip r ′ is as shown in FIG. As a result, the diameter of the corded rubber strip s4 on the winding roll becomes non-uniform (that is, the portion provided with the narrow strip r ′ is raised as compared with the other portions), and the corded rubber is There is a possibility that the strip s4 may be displaced in the axial direction on the winding roll, or the inner steel cord c may be deformed or wrinkled. If the belt is formed, and also adversely affect the performance of the tire.

  Therefore, according to the present invention, when the edge cover rubber is molded at the time of forming the belt, when the corded rubber strip with the edge cover rubber is wound around the winding roll, the position is shifted on the winding roll or the inside of the belt is formed. Provided is a method for manufacturing a tire belt capable of forming a highly accurate belt by preventing deformation and habit of a steel cord, and a pneumatic tire including a belt manufactured using the method. The purpose is to do.

  In order to solve the above-described problems, the tire belt manufacturing method of the present invention includes a plurality of reinforcing cords arranged in parallel at a predetermined interval, and the reinforcing cords are covered with unvulcanized rubber to enter the cords. A step of forming a rubber sheet, a step of cutting the cord-containing sheet linearly at a predetermined inclination angle with respect to the extending direction of the reinforcing cord for each predetermined length, and forming a cord-containing rubber sheet piece; The corded rubber sheet pieces are joined to each other in a strip shape with a straight cut edge as a side edge to form a corded rubber strip, and the corded rubber strip is not added while passing between a pair of calender rolls. A rubber strip with cords in which unvulcanized rubber is pressure-bonded by pressing and pressing the vulcanized rubber to both side edges of the rubber strip with cords by the calender roll. It is characterized in that comprises a step of forming an edge cover rubber with strips by cutting unnecessary portions of the unvulcanized rubber to be a predetermined width.

  In the tire belt manufacturing method of the present invention, the strip with edge cover rubber is wound up to form a winding roll, and then the strip with edge cover rubber fed out from the winding roll has a predetermined length. It is preferable to include a step of forming a belt by cutting it into pieces and attaching it onto a belt forming drum.

  The present invention is also characterized by a pneumatic tire manufactured using the tire belt manufactured by the above method.

  According to the tire belt manufacturing method of the present invention, since the edge cover rubber is attached to the corded rubber strap by a pair of calendar rolls, the thickness of the formed edge cover rubber is the corded rubber. Even if the strap with the edge cover rubber is wound up and used as a winding roll in the subsequent process, the position of the strap is displaced or the internal steel cord is deformed or distorted. It is possible to prevent the belt from being damaged, and as a result, a highly accurate belt can be provided.

  Further, according to the present invention, the edge cover rubber can be formed by directly sticking the rubber only to a necessary portion, so that the rubber necessary for forming the edge cover rubber can be minimized.

  And in the pneumatic tire manufactured in this way, the edge cover rubber can prevent separation at the end of the belt layer as well as the edge cover rubber as described above. Therefore, the weight can be reduced.

(A)-(d) is the figure which showed each process of the manufacturing method of the belt for tires of one Embodiment according to this invention. It is a figure which shows the edge cover rubber sticking apparatus used for the process of FIG.1 (c), (a) is an entrance side of an apparatus, (b) is an exit side of an apparatus, (c) is a strap with edge cover rubber. A sectional view taken along line AA is shown. (A)-(c) is the schematic which showed a mode that the edge cover rubber | gum was affixed on the rubber strip containing a cord using the apparatus of FIG. 2, respectively. It is a schematic perspective view of the winding roll formed by winding the strap with edge cover rubber around the winding shaft by the method of the embodiment of FIG. It is a tire width direction sectional view of the pneumatic tire manufactured using the method of the embodiment of FIG. Each of the windings when the strap with the edge cover rubber formed using the method of the present invention and the strap with the edge cover rubber formed using the method of the prior art are wound around the winding shaft to form a winding roll, respectively. It is a graph which shows the measurement result of the position shift which arose in the take-off roll. (A) is a figure explaining a mode that edge cover rubber | gum is affixed on the edge part of a corded rubber strap according to a prior art, (b), (c) is formed by the method of (a), respectively. FIG. 6 is a cross-sectional view in the width direction of a strap with edge cover rubber. It is a schematic perspective view which shows a mode that the strap with edge cover rubber | gum formed using the method of the prior art of FIG. 7 was wound up, and it was set as the winding roll.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1 to 3 show a tire belt manufacturing apparatus used in the tire belt manufacturing method of the present embodiment. In FIG. 1A, reference numeral 1 denotes a steel cord c as a reinforcing cord. Reference numeral 2 denotes a creel stand that is fed from 1a. Reference numeral 2 is an aligning device including a comb roll or a press roll that aligns the fed steel cord c. Reference numeral 3 is a calendar that presses unvulcanized compounded rubber on both surfaces of the steel cord c. Rolls 4 are winding shafts for winding a corded rubber sheet s1 made of a steel cord c coated with compounded rubber. Further, in FIG. 1B, reference numeral 5 denotes a cutter device that cuts the corded rubber sheet s1 fed from the winding roll of the corded rubber sheet s1 to obtain a corded rubber sheet piece s2. ) Is an edge cover rubber application device for attaching edge cover rubber r to both side edges of a corded rubber strip s3 formed by joining corded sheet pieces s2. In FIG. This is a winding shaft for winding a corded rubber strip with edge cover rubber (hereinafter referred to as “strip with edge cover rubber”) s4. The edge cover rubber affixing device 8 shown in detail in FIG. 2 includes a pair of calender rolls 12 and 13 and two sets provided on the side of the corded rubber strip s3 on the entrance side of the pair of calender rolls 12 and 13. The sheet guides 15 and 16 and a pair of sheet cutters 18 and 19 provided on the exit side of the pair of calendar rolls 12 and 13 are provided. In this edge cover sticking device 8, the distance between the pair of calendar rolls 12, 13 is the thickness of the belt to be manufactured, and in this example, it is 1 mm.

  First, as shown in FIG. 1A, the tire belt manufacturing method of the present embodiment uses a aligning device 2 to align a plurality of steel cords c fed from the bobbin 1a of the creel stand 1 with a predetermined cord interval. Place them in parallel underneath. The steel cord c may be either a stranded wire or a strand.

  Next, as shown in FIG. 1 (b), according to the hot calendering method, the steel cord c arranged in parallel is coated with unvulcanized compounded rubber using the calender roll 3 to obtain a cord-filled rubber sheet s1. . Here, the rubber coating may be applied by a known cold calender method or semi-hot calender method, or by using a coating head (not shown).

  The cord-containing rubber sheet s1 formed in this way is once wound around the winding shaft 4, and then conveyed to the cutter device 5, where a predetermined inclination with respect to the extending direction of the cord c is provided for each predetermined length. It is cut into a straight line at an angle to obtain a required cord-containing rubber sheet piece s2. The corded rubber sheet s1 may be directly conveyed to the cutter device 5 without being wound around the winding shaft 4. After that, the plurality of corded rubber sheet pieces s2 are joined to each other in a belt shape with their linear cut edges e1 and e2 as side edges to form a corded rubber strip s3. The joint of the corded rubber sheet piece s2 can be performed by a known joint device (not shown), and the joint system may be either a butt joint system or an overlap joint system.

  The corded rubber strip s3 formed by being jointed by the joint device is conveyed to the edge cover rubber affixing device 8, and the edge cover rubber r is pressure-bonded to both side edges of the corded rubber strip s3. More specifically, the corded rubber strip s3 is passed between the pair of calendar rolls 12, 13 of the edge cover rubber pasting device 8, and the edge cover rubber pasting device 8 feeds the cord while feeding the corded rubber strap s3. The unvulcanized rubber lump (also referred to as a bank) q set between the two sets of stock guides 15 and 16 respectively disposed on both sides of the rubber strap s3 is rolled to remove the unvulcanized rubber. Affixed to the side edge of the corded rubber strap s3. Further, an extra portion of the unvulcanized rubber rolled between the pair of calendar rolls 12 and 13 and attached to the side of the corded rubber strip s3 is a pair provided on the outlet side of the calendar rolls 12 and 13. Are cut by the sheet cutters 18 and 19 to form a corded rubber strip s4 with edge cover rubber having a predetermined width. The excess portion of the unvulcanized rubber that has been cut off makes a round while being stuck to the calender rolls 12 and 13, joined to the bang q set between the two sets of stock guides 15 and 16, and reused. The

  Then, the edge cover rubber-attached strip s4 with the edge cover rubber r attached to the side edge by the edge cover rubber attaching device 8 is wound around the take-up shaft 10 as shown in FIG. It is temporarily stored as a winding roll.

  Thereafter, according to a known method, the strip s4 with edge cover rubber fed out from the take-up roll that has been stored is cut to a required length for the belt and affixed on a belt molding drum (not shown) to form a belt. Next, the belt is combined with a tread band and a green case prepared in advance to form a green tire, and the green tire is vulcanized so that the end portions of the belt layers 24, 25, and 26 are as shown in FIG. A pneumatic tire covered with the edge cover rubber member 28 is obtained. That is, the pneumatic tire includes a pair of bead portions 31, a pair of sidewall portions 32 continuous to the tire radial direction outer side of the pair of bead portions 31, and a tread portion 33 straddling the pair of sidewall portions. A carcass 35 composed of one or more plies that extend between the pair of bead cores 34 in a toroidal manner and reinforce the parts 31, 32, 33, and a tread that is disposed on the outer side in the tire radial direction of the crown portion of the carcass 35. At least one layer (here, three layers) of belt layers 24, 25, and 26 that reinforce the portion 33 is provided, and the end portions in the width direction of the belt layers 24, 25, and 26 are substantially equal to the belt layers 24, 25, and 26. The edge cover rubber member 28 is covered with a thickness.

  In such a tire belt manufacturing method, the edge cover rubber r is attached to the corded rubber strap s3 by the pair of calender rolls 12 and 13, so that the edge cover rubber is formed. The thickness of r is equal to the thickness of the corded rubber strap s3. In the subsequent process, even when the edge cover rubber-equipped strap s4 is wound around the winding shaft 10 to form a winding roll, the position of the strap is shifted on the winding roll. Can be prevented, and deformation or habit of the internal steel cord c can be prevented, and as a result, a highly accurate belt can be provided.

  Further, as shown in comparison with FIG. 7, conventionally, the edge cover rubber member is formed on the edge portion of the belt layer by using the rubber flow during vulcanization. According to the present invention, since a large amount of rubber is required for forming, the edge cover rubber can be formed by directly attaching the rubber only to a necessary portion, so that the rubber necessary for forming the edge cover rubber Can be minimized. As a specific example, conventionally, the width w ′ of the insertion rubber for forming the edge cover rubber (see FIG. 7B) was required to be 10 to 25 mm. The width w (see FIG. 2C) is about 0.5 to 3 mm.

  In the pneumatic tire manufactured as described above, the edge cover rubber member 28 can prevent separation at the end portions of the belt layers 24, 25, and 26, as described above. Since the edge cover rubber r for forming the rubber member 28 can be minimized, the weight can be reduced.

  Next, a corded rubber strip with an edge cover rubber formed according to the method of the prior art and a corded rubber strip with an edge cover rubber formed according to the method of the present invention are prepared and wound around a winding shaft, respectively. The amount of positional deviation of the corded rubber strip on the winding roll at that time was measured, and the result is shown in FIG.

  In the graph in FIG. 6, the horizontal axis indicates the number of windings of the winding roll, and the vertical axis indicates that the corded rubber strip s4 on the winding roll is in the axial direction relative to the reference of the winding shaft 10. It indicates how much the position has shifted (the position has shifted). In the vertical axis, “+” indicates a positional shift to one side in the axial direction of the winding shaft, and “−” indicates a positional shift to the other side in the axial direction of the winding shaft. This indicates that the positional deviation is large. In the graph, the permissible value of misalignment (value on the vertical axis) should be less than or equal to the broken line, and if it exceeds the broken line, the steel cord is excessively deformed and wrinkled and cannot be used as a belt material. Shall mean.

  As is apparent from the graph of FIG. 6, in the conventional method, as the number of windings increases, the positional deviation of the corded rubber strap on the winding roll increases, resulting in a defective product. According to the tire belt manufacturing method of the invention, even if the number of windings is increased, the positional deviation is within an allowable range (below the broken line), and it is possible to prevent the generation of defective products.

  Thus, according to the present invention, when forming the edge cover rubber at the time of forming the belt, when the corded rubber strip with the edge cover rubber is wound around the winding roll, a position shift occurs on the winding roll or the inner steel is formed. Provided is a method for manufacturing a tire belt capable of forming a highly accurate belt by preventing the cord from being deformed or wrinkled, and a pneumatic tire including the belt manufactured by using the method. It became possible.

c Steel cord r Edge cover rubber s1 Rubber sheet with cord s2 Rubber sheet piece with cord s3 Rubber strip with cord s4 Rubber strip with cord with edge cover rubber 8 Edge cover rubber application device 12, 13 Calendar roll 15, 16 Stock guide 18, 19 Sheet cutter

Claims (3)

A method for manufacturing a tire belt for use in manufacturing a pneumatic tire,
In a state where a plurality of reinforcing cords are arranged in parallel at a predetermined interval, a step of coating the reinforcing cords with unvulcanized rubber to form a corded rubber sheet;
Cutting the corded sheet linearly at a predetermined inclination angle with respect to the extending direction of the reinforcing cord for each predetermined length to form a corded rubber sheet piece;
A step of joining the corded rubber sheet pieces to each other with a linear cut edge as a side edge to form a corded rubber strip; and
While passing the corded rubber strip between a pair of calender rolls, uncured rubber is extruded and crimped to both side edges of the corded rubber strip by the calender roll, and corded rubber to which the unvulcanized rubber is crimped Cutting the excess portion of the unvulcanized rubber to form a strip with edge cover rubber so that the strip has a predetermined width.   After winding the strip with the edge cover rubber into a winding roll, the strip with the edge cover rubber fed out from the winding roll is cut into a predetermined length and attached onto a belt forming drum to form a belt. The manufacturing method of the belt for tires of Claim 1 including a process.   A pneumatic tire manufactured using the tire belt according to claim 1.

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