JP2016147383A - Method for manufacturing pneumatic tire, and pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a uniformity while increasing production efficiency of a green tire.SOLUTION: A core construction method includes a process in which a belt ply, in which strip pieces are located in a tire circumferential direction, is formed. This process includes a pasting step of circulating a rigid core by n rounds at one pasting station, and pasting the strip pieces at each round. In the first round pasting step, the strip pieces are pasted over one round in a cutting order thereof and with a clearance D of (n-1) piece therebetween. In the n-th round pasting step, following the (n-1) round pasting step, the strip pieces are pasted over one round in the cutting order thereof and one by one in the clearance D, and further, the strip pieces are so pasted as to be adjacent to the strip pieces which have been pasted in the (n-1)th round.SELECTED DRAWING: Figure 9

Description

  The present invention relates to a pneumatic tire manufacturing method for improving uniformity in a core method, and a pneumatic tire.

  Patent Document 1 below proposes a tire manufacturing method (sometimes referred to as a “core method”) using a rigid core having an outer shape substantially equal to the lumen shape of a vulcanized tire. In this proposed core method, a raw tire is formed by sequentially sticking tire components onto a rigid core, and a raw tire is inserted into a vulcanization mold together with the rigid core. And a vulcanization step of vulcanization molding.

  Further, in the green tire forming step, the belt ply a forming one of the tire constituent members is a tire having a plurality of strips c on the rigid core b as shown in FIGS. 11 (A) and 11 (B). It is formed by sticking sequentially in the circumferential direction. The strip c is formed by sequentially cutting a narrow and long rubber strip d having a belt cord f aligned in the length direction at a predetermined length. The rubber strip d is continuously formed by a topping device using a rubber extruder, and the rubber strip d is once wound in a roll and stored.

  When forming the raw tire, the roll body of the rubber strip d is supplied to a belt ply forming station, and the rubber strip d rewound from the roll body is sequentially cut from the leading end side and cut. The strips c are attached to the rigid core b in the cutting order.

  However, in the case of a roll body, the rubber strip d is deformed to have a larger strip width and a larger belt cord interval toward the radially inner end side (winding start side) due to the influence of tension or the like. For example, in the case of a rubber strip d having a length of 180 to 200 m, a difference of 0.25 to 0.30 mm occurs in the strip width between the radially inner end (winding end) and the radially outer end (winding end). To do.

  Accordingly, when the roll body is used up in the course of forming the belt ply and is replaced with a new roll body, as shown in FIG. 12 (A), as shown in FIG. ) To the region of the strip strip ca (the strip width is large) and the strip strip cb (the strip width is small) formed from the radially outer side (winding end side) of the roll body after replacement. Divided in the direction. As a result, unevenness occurs in the circumferential direction, resulting in a decrease in uniformity, such as worsening the roundness of the tire.

  On the other hand, in the belt ply formation process, since the number of strips attached is very large, the process time becomes long, which is one of the causes of a decrease in production efficiency of raw tires. For this reason, it is desirable to reduce the cycle time by attaching the strip pieces by dividing them by a plurality of stations. However, even when strip strips are pasted continuously in each station, strip strips c1 pasted at one station P1, as shown in FIG. 12 (B), when divided into two stations P1 and P2. And the area of the strip c2 to be pasted at the other station P2 are divided into two in the circumferential direction. As a result, the uniformity is reduced as described above. In addition, when the roll body is exchanged in at least one of the stations, the deterioration of the uniformity is further increased.

International Publication WO2014 / 054403

  This invention makes it a subject to provide the manufacturing method of the pneumatic tire which improves uniformity in a core construction method, and a pneumatic tire.

The first invention of the present application is a raw tire forming step of forming a raw tire by sequentially sticking a tire constituent member including an unvulcanized belt ply on a rigid core;
A method of manufacturing a pneumatic tire comprising a vulcanization step of vulcanizing and molding the raw tire together with the rigid core into a vulcanization mold,
The raw tire forming step includes a belt ply forming step of forming a belt ply arranged in the tire circumferential direction without overlapping a plurality of strips.
The strip piece uses a roll body in which a narrow and long rubber strip having a belt cord aligned in the length direction is wound in a roll shape, and the rubber strip unwound from the roll body is It is formed by sequentially cutting at a predetermined length,
The belt ply forming step includes a pasting step in which a rigid core is n-turned in one pasting station and a strip is pasted for each round,
In the pasting step of the first round, the strip pieces are pasted in the tire circumferential direction over the entire circumference in the cutting order and with an interval D of (n-1) skipping,
In the n-th pasting step, following the preceding (n-1) -th pasting step, the strips are cut one by one in the interval D and in the interval D, and (n-1). ) Adjacent to the strips pasted in the pasting step of the circumference, and pasted in the tire circumferential direction over the entire circumference,
As a result, the strips to be attached within the same lap form a belt ply that is distributed in the tire circumferential direction so as to skip (n-1) sheets.

In the second invention of the present application, a raw tire forming step of forming a raw tire by sequentially sticking tire constituent members including unvulcanized belt plies on the rigid core;
A method of manufacturing a pneumatic tire comprising a vulcanization step of vulcanizing and molding the raw tire together with the rigid core into a vulcanization mold,
The raw tire forming step includes a belt ply forming step of forming a belt ply arranged in the tire circumferential direction without overlapping a plurality of strips.
The strips use first to n-th roll bodies in which narrow rubber strips having belt cords aligned in the length direction are wound in a roll shape, and the first to n-th roll bodies are used. Each of the rubber strips rewound from each of the first to nth strips formed by sequentially cutting at a predetermined length from the tip side,
The belt ply forming step includes a pasting step in which the first to nth strips are separately pasted at first to nth pasting stations, respectively.
In addition, in the first round of pasting step, the first strip of strips in the first pasting station is in the tire circumferential direction over the entire circumference in the cutting order and with an interval D of (n-1) skips. Pasted on,
In the n-th pasting step, after the preceding (n-1) -th pasting step, the n-th strip piece is placed in the cutting order and within each interval D at the n-th pasting station. Affixed in the tire circumferential direction over the entire circumference, adjacent to the (n-1) th strip strip attached in the (n-1) th pasting step, one by one.
Accordingly, the first to nth strips form a belt ply that is dispersedly arranged in the tire circumferential direction in such a manner that (n-1) pieces are skipped.

  In the belt ply forming process according to the first invention, as described above, the belt ply forming step includes a pasting step of sequentially pasting the strips cut out from one roll body in the cutting order for each turn of the rigid core. In each pasting step, the strips are pasted over the entire circumference with an interval of (n-1) skipping. As a result, it is possible to form a belt ply in which strips to be attached within the same lap are distributed in the tire circumferential direction so as to skip (n-1) sheets.

  Therefore, even when the roll body is newly replaced in the course of circulation, the wide strip before replacement and the narrow strip after replacement are distributed in the circumferential direction without being arranged next to each other. Is done. Therefore, unevenness in steps can be prevented, and uniformity can be improved.

  Further, in the belt ply forming step according to the second aspect of the invention, as described above, the strips are pasted into the first to nth pasting stations. Therefore, the cycle time can be shortened to about 1 / n as compared with the case where no division is performed.

  Further, in each pasting station, strips formed from the respective roll bodies are pasted over the entire circumference in the respective cutting orders and at intervals of (n-1) sheets. As a result, a belt ply is formed in which the (n-1) strips of the first to nth strips are dispersedly arranged in the tire circumferential direction.

  In such a belt ply, for example, the first strip is formed from the radially inner side (winding start side) of the roll body, and the second strip is formed from the radially outer side (winding end side) of the roll body. In this case, the uniformity can be improved because each of them is distributed in the circumferential direction.

  In addition, when the roll body is newly replaced in at least one pasting station, for example, when the roll body is newly replaced with the first roll body in the first pasting station, the width before replacement is included in the first strip. Wide strips and narrow strips after replacement are mixed. However, since the 2nd to nth strips are interposed between the wide strip and the narrow strip, the uniformity can be improved.

It is sectional drawing which shows one Example of the pneumatic tire formed by the manufacturing method of this invention. It is sectional drawing which shows a raw tire formation process. It is sectional drawing which shows a vulcanization | cure process. (A), (B) is the fragmentary top view explaining a belt ply formation process, and sectional drawing on a tire equator. It is a perspective view which shows the formation method of the strip piece from a roll body. It is the conceptual diagram which looked at the 1st-nth sticking station from the upper part. (A) is a side view representative of the n-th pasting station, and (B) is a plan view for explaining the operation of the pasting apparatus. (A)-(C) are the conceptual diagrams which show sticking of the strip piece by the 1st-nth (n = 3) sticking step. It is a conceptual diagram explaining the belt ply formation process of 2nd Embodiment. It is a conceptual diagram explaining the problem. (A), (B) is a perspective view explaining the manufacturing method of the conventional pneumatic tire using the rigid core. (A), (B) is a conceptual diagram explaining the problem.

Hereinafter, embodiments of the present invention will be described in detail.
FIG. 1 is a cross-sectional view showing an example of a pneumatic tire 1 formed by the manufacturing method of the present invention. A pneumatic tire 1 according to this embodiment includes a carcass 6 that extends from a tread portion 2 through a sidewall portion 3 to bead portions 4 on both sides, and a belt disposed radially outside the carcass 6 and inside the tread portion 2. With layer 7.

  The carcass 6 is formed of a carcass ply 6A in which carcass cords are arranged at an angle of, for example, 50 to 90 ° with respect to the tire circumferential direction. The carcass ply 6 </ b> A has a toroidal shape straddling the bead portions 4 and 4. Each bead portion 4 is provided with a bead core 5 including core pieces 5i and 5o inside and outside in the tire axial direction. Each of the core pieces 5i and 5o has a ring shape in which a bead wire is wound in a spiral shape, and is sandwiched between the core pieces 5i and 5o so that both ends of the carcass ply 6A are locked. Further, a tapered bead apex 8 made of hard rubber having a durometer A hardness of, for example, 70 to 100 degrees is disposed on the outer side of each core piece 5i, 5o in the tire radial direction.

  The belt layer 7 is formed of two or more belt plies 7A and 7A in this example, in which belt cords are arranged at an angle of, for example, 10 to 60 ° with respect to the tire circumferential direction. The belt layer 7 enhances the belt rigidity by crossing the belt cords between the plies, and reinforces substantially the entire width of the tread portion 2 with a tagging effect. In this example, a band layer 9 in which a band cord is spirally wound in the circumferential direction is arranged on the outer side in the radial direction of the belt layer 7 for the purpose of improving high-speed performance.

  A non-air permeable inner liner rubber 10 forming a tire lumen surface is disposed inside the carcass 6. Further, on the outside of the carcass 6, a sidewall rubber Sg that forms the outer surface of the sidewall portion 3 and a tread rubber Tg that forms the outer surface of the tread portion 2 are disposed. Further, clinching rubber Cg for preventing rim deviation is arranged on the outside of the bead core 5.

  Next, a method for manufacturing the pneumatic tire 1 will be described. This manufacturing method includes a raw tire forming step K1 and a vulcanizing step K2. As shown schematically in FIG. 2, in the raw tire forming step K <b> 1, the tire constituent members including the unvulcanized belt ply 7 </ b> A are sequentially attached onto the rigid core 20 to form the raw tire 1 </ b> N. As shown schematically in FIG. 3, in the vulcanization step K <b> 2, the raw tire 1 </ b> N is put into the vulcanization mold 24 together with the rigid core 20, whereby the rigid core 20 and the vulcanization mold 24 are separated. The raw tire 1N is vulcanized and molded between. The rigid core 20 has a well-known structure, and the outer shape thereof substantially matches the lumen shape of the pneumatic tire 1.

  The raw tire forming step K1 includes an inner liner forming step of attaching a member for forming the inner liner rubber 10 to the rigid core 20, a carcass ply forming step of attaching a member for forming the carcass ply 6A, and a bead core 5 forming step. A bead core forming step for attaching a member, a bead apex forming step for attaching a member for forming a bead apex 8, a belt forming step for attaching a member for forming the belt ply 7A, and a band forming step for attaching a member for forming the band layer 9 And a sidewall molding step for attaching a member for forming the sidewall rubber Sg, a tread molding step for attaching a member for forming the tread rubber Tg, and the like.

  Among these, in the processes other than the belt ply forming process, various known ones using the rigid core 20 can be appropriately employed. Therefore, in this specification, only the belt ply forming step will be described below.

  As shown in FIGS. 4A and 4B, in the belt ply forming step, the uncured belt ply 7A is formed by arranging a plurality of strip pieces 12 in the tire circumferential direction without overlapping. . The gap g on the tire equator Co between the strips 12 and 12 is preferably 2.0 mm or less, more preferably 1.5 mm or less. If the gap g exceeds 2.0 mm, this portion becomes a weak point during high-speed rotation and the durability is lowered.

<First Embodiment (related to the second invention)
In the belt ply forming step of the first embodiment, the strip 12 is composed of _first to _n-th strips 12 _{1 to} 12 _n . In this example, the case of n = 3 is shown.

As shown in FIG. 5, each strip 12 is formed in a strip shape having a length L larger than the width W, and the length direction thereof is affixed in accordance with the direction of the belt cord 14 a of the pneumatic tire 1. The The width W is preferably in the range of 10 to 50 mm. Each of the first to n-th strips 12 _{1 to} 12 _n has a narrow length of rubber strip 14 rewound from the _first to n-th roll bodies 13 _{1 to} 13 _n with a predetermined length from the tip side. It is formed by sequentially cutting. The rubber strip 14 is formed by, for example, using a topping device having a rubber extruder and covering an array of belt cords 14a aligned in the length direction with topping rubber. By winding the rubber strip 14 in a roll shape, the first to n-th roll bodies 13 _{1 to} 13 _n are formed, respectively. That is, each of the _first to nth roll bodies 13 _{1 to} 13 _n is formed of a rubber strip 14 having substantially the same configuration.

FIG. 6 is a conceptual view of a part of the production line as viewed from above. As shown in the figure, the production line is provided with first to n-th pasting stations P _{1 to} P _n . The belt ply forming step, the at first to joining station _P 1 to P _n of the n, joining steps _S 1 ~ of the first to n paste respective strips ₁₂ 1 to 12 _n into separate It comprises a S _n. The first to n-th pasting stations P _{1 to} P _n are provided on the transport track of the rigid core 20. The rigid core 20, first the first through while being stoppable transported to joining each station _P 1 to P _n of the n, to give first the a joining station _{P 1} a first paste the strips 12 ₁ joining step S ₁ is performed, the joining step S _n of the n is performed to paste strips 12 _n of joining stations P _n in the n-th of the n.

FIG. 7A representatively shows a side view of the n-th pasting station _Pn . Note that the first to n-th pasting stations P _{1 to} P _n have substantially the same configuration, and in this example, the pasting station P _n is a reel stand 30 that rotatably holds the roll body 13 _n and the roll body. a strip transport unit 32 which transports the rubber strip 14 unwound from the 13 _n, and the cutting means 33 for forming the strips 12 _n by cutting the rubber strip 14 that has been conveyed, the rigid core receives the strips 12 _n 20 and a pasting device 34 for pasting to 20. In the joining apparatus 34, as shown in FIG. 7 (B), it supplies the strips 12 _n along its length. The rigid core 20 is disposed with its circumferential direction inclined at an angle θ (angle of the belt cord) with respect to the length direction. Then, the rigidity core 20, in accordance with the supply of the strips 12 _n, by rotating at about the axis while moving in the axial direction, the strips 12 _n at an angle of angle θ with respect to the circumferential direction Can be pasted. Thus, in this example, for each of the first to n-th pasting stations P _{1 to} P _n , cutting of the strip pieces 12 _{1 to} 12 _n from the respective roll bodies 13 _{1 to} 13 _n and the cut strip pieces The pasting of 12 _{1 to} 12 _n is performed.

Also as schematically shown in FIG. 8 (A), the first joining step _{S 1,} and wherein at a first joining station _{P 1,} the first strips 12 _1, its cut order (n- 1) Affixing in the tire circumferential direction over the entire circumference with an interval D of sheet skipping.

Also as schematically shown in FIG. 8 (B), in the second joining step S _2, after the first joining step S _1, in the second joining station P _2, the second strips 12 ₂ are pasted in the tire circumferential direction over the entire circumference, adjacent to the _first strip 121, which is pasted in the cutting order and within each interval D, and adjacent to the _first strip 121.

Also as schematically shown in FIG. 8 (C), in the joining step _{S n} of the n, after joining step _{S n-1} of the (n-1) which precedes, by joining station _{P n} of the n the strips 12 _n of the n, the and the off order one by one in each interval D, moreover the (n-1 which is adhered at the joining step S _n-1 of the (n-1) th ) In the tire circumferential direction over the entire circumference adjacent to the strip 12 _n-1 .

Thereby, the belt ply 7A in which the first to n- _th strip pieces 12 _{1 to} 12 _n are dispersedly arranged in the tire circumferential direction so that (n−1) pieces are skipped can be formed.

As a result, for example, the first strips 12 ₁ is formed from a radially inner side of the roll body 13 ₁ (winding start side), the second strips 12 ₂ radially outwardly of the roll body 13 ₂ (winding end side) Even when formed from the above, since they are dispersedly arranged in the circumferential direction, uniformity can be improved.

At least in one joining station, when replacing the roll body to the new, for example, when replacing the first roll body 13 ₁ in the first joining station P ₁ to the new roll body, the first strips the 12 _1, between the strips of the wide width before replacement, but the width narrow strips after replacement will be mixed, also in this case, the strips and Habasema of strips of wide width In addition, since the second to nth strips 12 ₂ and 12 _n are interposed, uniformity can be improved.

  Note that an integer of 2 or more can be appropriately adopted as the “n”, but if it is too large, it is disadvantageous for equipment cost, line space, transfer time and the like. Therefore, n is preferably 2, 3 or 4.

<Second Embodiment (related to the first invention)
In the belt ply forming process of the second embodiment, a single attaching station P0 includes an attaching step S0 in which the rigid core 20 is rotated n times, and the strips 12 are attached every turn. In this example, the case of n = 3 is shown. As shown schematically in FIG. 9, the first lap pasting step S0 _1, the strips 12, the circumferential over the circumference at a distance D of the cutting sequence a and (n-1) Like jumping Paste in the direction. In the figure, for the sake of convenience, the strip piece 12 attached on the first turn, the strip piece 12 attached on the second turn, and the strip piece 12 attached on the n (= 3) turn are shaded. However, they are formed from the same roll body 13 except for roller replacement.

  In the belt ply 7A formed in this way, the strip pieces 12 to be attached within the same lap are distributed and arranged in the tire circumferential direction so as to skip (n-1) sheets, so that the uniformity can be improved. However, for example, when n = 2 is illustrated in FIG. 10, when the roller is replaced in the middle of the first round, the wide strip 12a before the replacement is dispersed, but the width after the replacement is narrow. A region Y in which the strip pieces 12b continue is generated. Therefore, in the second embodiment, the dispersion effect tends to be inferior to that of the first embodiment.

  As mentioned above, although especially preferable embodiment of this invention was explained in full detail, this invention is not limited to embodiment of illustration, It can deform | transform and implement in a various aspect.

A tire for a passenger car (tire size 245 / 45R18) having the structure shown in FIG. 1 using a rigid core was manufactured based on the specifications shown in Table 1, and the uniformity and production efficiency of each tire were tested. The manufacturing method is the same except for the belt ply forming step. The main common specifications are as follows.
・ Number of belt plies: 2 ・ Belt cord angle: 22 °
・ Belt ply width: 214mm
・ Belt ply circumference: 2035mm (equator position), 1997mm (belt end position)
・ Ply width of strip ply piece: 28mm
・ Number of strip ply pieces: 26

  In Comparative Example 1, the strip pieces are pasted without leaving a gap D at one pasting station. In Comparative Example 2, the strip pieces are pasted by ½ round without leaving the interval D at the two pasting stations. In Comparative Example 3, the strip pieces are pasted by 1/3 rounds without any interval D at the three pasting stations. In Comparative Example 4, a single strip is made two rounds with a gap D between two strips at one pasting station. In Comparative Example 5, three strips are separated by an interval D between two strips at one pasting station.

(1) Uniformity:
In accordance with JASO C607: 2000 “Automotive Tire Uniformity Test Method”, the RFV of 30 tires was measured, and the average value of each tire was evaluated by a 10-point method. The larger the value, the better the uniformity.

(2) Production efficiency:
The number of green tires that passed through the belt ply formation process during 60 minutes was evaluated by a 10-point method. The larger the value, the better the production efficiency.

  As shown in the table, in the examples, it is possible to suppress the deterioration of uniformity due to the roll body replacement. In particular, it can be confirmed that the production efficiency can be subtracted while suppressing the deterioration of uniformity in the first embodiment.

1N raw tire 7A belt ply 12, 121 to 12n 1st to nth strips 13, 131 to 13n 1st to nth roll body 14 rubber strip 14a belt cord 20 rigid core 24 vulcanization mold Co tire equator K1 green tire formation process K2 vulcanization process P1-Pn 1st-nth pasting station S1-Sn 1st-nth pasting step

Claims (5)

On the rigid core, a raw tire forming step of forming a raw tire by sequentially attaching tire constituent members including an unvulcanized belt ply; and
A method of manufacturing a pneumatic tire comprising a vulcanization step of vulcanizing and molding the raw tire together with the rigid core into a vulcanization mold,
The raw tire forming step includes a belt ply forming step of forming a belt ply arranged in the tire circumferential direction without overlapping a plurality of strips.
The strip piece uses a roll body in which a narrow and long rubber strip having a belt cord aligned in the length direction is wound in a roll shape, and the rubber strip unwound from the roll body is It is formed by sequentially cutting at a predetermined length,
The belt ply forming step includes a pasting step in which a rigid core is n-turned in one pasting station and a strip is pasted for each round,
In the pasting step of the first round, the strip pieces are pasted in the tire circumferential direction over the entire circumference in the cutting order and with an interval D of (n-1) skipping,
In the n-th pasting step, following the preceding (n-1) -th pasting step, the strips are cut one by one in the interval D and in the interval D, and (n-1). ) Adjacent to the strips pasted in the pasting step of the circumference, and pasted in the tire circumferential direction over the entire circumference,
Thereby, the strip piece stuck in the same circumference forms the belt ply by which the (n-1) sheet jump was distributedly arranged in the tire peripheral direction, The manufacturing method of the pneumatic tire characterized by the above-mentioned. On the rigid core, a raw tire forming step of forming a raw tire by sequentially attaching tire constituent members including an unvulcanized belt ply; and
A method of manufacturing a pneumatic tire comprising a vulcanization step of vulcanizing and molding the raw tire together with the rigid core into a vulcanization mold,
The raw tire forming step includes a belt ply forming step of forming a belt ply arranged in the tire circumferential direction without overlapping a plurality of strips.
The strips use first to n-th roll bodies in which narrow rubber strips having belt cords aligned in the length direction are wound in a roll shape, and the first to n-th roll bodies are used. Each of the rubber strips rewound from each of the first to nth strips formed by sequentially cutting at a predetermined length from the tip side,
The belt ply forming step includes a pasting step in which the first to nth strips are separately pasted at first to nth pasting stations, respectively.
In addition, in the first round of pasting step, the first strip of strips in the first pasting station is in the tire circumferential direction over the entire circumference in the cutting order and with an interval D of (n-1) skips. Pasted on,
In the n-th pasting step, after the preceding (n-1) -th pasting step, the n-th strip piece is placed in the cutting order and within each interval D at the n-th pasting station. Affixed in the tire circumferential direction over the entire circumference, adjacent to the (n-1) th strip strip attached in the (n-1) th pasting step, one by one.
Thereby, the 1st-nth strip piece forms the belt ply by which the (n-1) piece jump was distributedly arranged in the tire peripheral direction, respectively, The manufacturing method of the pneumatic tire characterized by the above-mentioned.   3. The pneumatic tire according to claim 2, wherein for each of the first to n-th pasting stations, cutting of the strip pieces from the respective roll bodies and pasting of the cut strip pieces are performed. Production method.   The rigid core is transported in a stoppable manner for each of the first to n-th pasting stations, and each pasting step is performed at the pasting station to be stopped. Method of manufacturing a pneumatic tire.   A pneumatic tire formed by the manufacturing method according to claim 1.