JP4819643B2 - Emergency bias tire manufacturing method and emergency bias tire - Google Patents

Description

  The present invention relates to an emergency bias tire manufacturing method for manufacturing an emergency bias tire that is used when a target tire (regular tire) that is normally mounted is defective.

  In recent years, as an emergency bias tire mounted on four-wheeled vehicles such as passenger cars, the tire outer diameter is substantially the same as the target tire that is normally used for weight reduction and space saving, and the tire width is There is an emergency bias tire with a bias structure called a T-type emergency tire that is extremely narrow and has a high internal pressure.

In emergency bias tires, light weight and cost are important quality requirements, with two carcass plies having one carcass ply having the optimum structure for this requirement. (For example, refer to Patent Documents 1 and 2.)
JP-A-1-95906 Japanese Patent Laid-Open No. 3-176204

In emergency bias tires with one carcass ply, the carcass ply turn-up part is overlapped by the outer peripheral part of the carcass ply body (so-called crown part), so the carcass structure is asymmetrical with respect to the tire equatorial plane. As a result, non-uniformity of the inner liner gauge occurs in the cross-sectional direction along the tire rotation axis.
The non-uniformity of the inner liner gauge is one of important quality characteristics because it deteriorates the durability against aging during storage.

  Such non-uniformity of the inner liner gauge is caused by a shape change during vulcanization. In the bias tire, this shape change is caused by a change in the angle of the ply cord, and the folded portion of the carcass ply contracts due to the change in the angle of the ply cord, and a ply rubber flow is generated near the end of the ply. Is pulled into the carcass ply side, resulting in a difference between the vicinity of the ply end of the folded portion of the carcass ply and the inner liner gauge of the other portions.

  In order to solve this problem, the conventional technology supports such as thickening the gauge of the inner liner in the entire cross-sectional direction. In this case, of course, the weight and cost increase, as well as Chris (Crease: in the vulcanization process) There is a problem of increasing product defects such as a bowl-shaped rubber reservoir that occurs when a portion of the inner liner rubber is compressed.

  In consideration of the above-mentioned facts, the present invention is a method for manufacturing an emergency bias tire that can efficiently manufacture an emergency bias tire that is lightweight and has excellent durability over time during storage, and a lightweight and time-dependent storage tire during storage. The purpose is to provide an emergency bias tire excellent in deterioration durability.

  According to the first aspect of the present invention, there is provided a single carcass ply in which a plurality of organic fiber cords are arranged in a direction inclined with respect to the tire equatorial plane and continuously extending from one bead core to the other bead core. A method of manufacturing an emergency bias tire in which a folded back and forth carcass ply around a tire is overlapped with a crown portion of a carcass ply main body portion extending from one bead core to the other bead core. A rubber layer is disposed between the carcass ply main body and the ply end of the folded carcass ply located on the inner side in the tire radial direction when the carcass ply attached to the outside of the inner liner is folded. It is a feature.

In the manufacturing method of the emergency bias tire according to claim 1, by arranging a rubber layer between the carcass ply main body portion and the ply end of the folded carcass ply located on the inner side in the tire radial direction at the time of molding the tire, This rubber layer can suppress the pulling of the inner liner rubber due to the movement of the ply end during vulcanization, and can make the gauge of the inner liner constant.
Here, the constant gauge means that “minimum gauge / maximum gauge” is 0.7 or more.

  The invention according to claim 2 is the emergency bias tire according to claim 1, wherein the rubber layer is the same rubber as the covering rubber covering the organic fiber cord of the carcass ply, and the gauge is 0.3 to 0.8 times the diameter of the organic fiber cord, and the width when viewed in a cross section along the tire rotation axis is 0.3 to 1.1 times the width of the overlapping portion of the folded carcass ply It is characterized by that.

If the rubber layer placed between the carcass ply body and the ply end of the folded carcass ply located on the inner side in the tire radial direction is made of a different type of rubber from the carcass ply covering rubber, problems such as peeling from the rubber boundary will occur. May occur.
If the gauge of the rubber layer is less than 0.3 times the diameter of the organic fiber cord, the effect of preventing the rubber flow is insufficient, and if the gauge of the rubber layer exceeds 0.8 times the diameter of the organic fiber cord, the air enters. Increased product defects.

  In addition, when the width of the rubber layer is less than 0.3 times the width of the overlapping portion of the carcass ply, it is difficult to obtain installation accuracy due to the variation in the shrinkage rate in the overlapping portion of the carcass ply, and the width of the rubber layer is not equal to that of the overlapping portion of the carcass ply. When the width exceeds 1.1 times, the effect of providing the rubber layer reaches its peak, and the mass increases unnecessarily, and the cost also increases unnecessarily.

  According to a third aspect of the present invention, there is provided a single carcass ply in which a plurality of organic fiber cords are arranged in a direction inclined with respect to a tire equatorial plane and continuously extending from one bead core to the other bead core. Is an emergency bias tire in which the left and right folded carcass plies are overlapped by the crown portion of the carcass ply main body extending from one bead core to the other bead core, A rubber layer is disposed between the carcass ply main body and the ply end of the folded carcass ply located on the inner side in the tire radial direction when the carcass ply attached to the outside of the liner is folded back. Yes.

  4. The emergency bias tire according to claim 3, wherein when the carcass ply attached to the outside of the inner liner is folded during molding, the carcass ply main body and the ply end of the folded carcass ply located on the inner side in the tire radial direction. Since the rubber layer is placed between the two, the rubber layer is pulled toward the ply end during vulcanization, so that the inner liner is prevented from being pulled in, and the gauge of the inner liner is constant in the product tire. .

  As described above, according to the method for manufacturing an emergency bias tire of the present invention, there is an excellent effect that it is possible to efficiently manufacture an emergency bias tire that is light in weight and excellent in aging durability during storage.

  Moreover, according to the emergency bias tire of the present invention, it has an excellent effect that it is lightweight and has excellent aging durability during storage.

An embodiment of an emergency bias tire according to the present invention will be described with reference to the drawings.
As shown in FIG. 1, an emergency bias tire 10 according to this embodiment includes a pair of bead cores 12 and a bias structure for a four-wheeled vehicle including a carcass 14 straddling a pair of bead cores 12 in a toroid shape. This is a bias tire (a “T-type emergency tire for passenger cars” in JATMA standards).
An inner liner 18 is disposed on the inner peripheral surface side of the carcass 14, a tread rubber 22 constituting a tread portion 20 is disposed on the outer peripheral surface side, and sidewalls 26 are formed on both side surfaces over the bead portions 24. Side rubber 28 is arranged.

  The carcass 14 is composed of a single carcass ply 30. The carcass ply 30 has the bead core 12 folded back from the inside of the tire to the outside, and the folded portion 30A is disposed along the main body 30B and extends outward in the tire radial direction. It is arranged in a range exceeding 20A and not exceeding the other tread end portion 20A exceeding the tire equatorial plane CL.

The carcass ply 30 has a known structure in which a large number of ply cords made of organic fibers arranged in parallel with each other are coated with a coating rubber.
The gauge of the carcass ply 30 is preferably in the range of 1.1 to 1.5 times the diameter of the ply cord.

Further, the carcass ply 30 is overlapped at both ends in the width direction in the tread portion 20.
Here, the overlap amount OLW of the carcass ply 30 is preferably in the range of 40 to 90% of the tread width TW, and more preferably in the range of 50 to 70%.

  A reinforcing rubber layer 32 is disposed between the ply end 30E inside the tire of the carcass ply 30 and the main body 30B. The ply end 30E and the center of the reinforcing rubber layer 32 in the width direction are made to coincide. The rubber used for the reinforcing rubber layer 32 is the same rubber as the coating rubber that coats the ply cord of the carcass ply 30.

Next, the manufacturing process of the emergency bias tire 10 of this embodiment will be briefly described.
As shown in FIG. 2, the emergency bias tire 10 according to the present embodiment is arranged on the both sides of the center drum 40 whose outer diameter can be expanded and contracted, and the outer diameter can be expanded and contracted and moved in the axial direction. A raw tire is molded using a tire molding drum 44 including a side drum 42.

  In the side drum 42, a plurality of thin metal blades (not shown) extending in the axial direction are arranged so as to form a drum shape in the circumferential direction, and the interval between the blades and the blades changes by expanding and contracting. A spring 46 wound in a coil shape is rotatably supported at the end of the side drum 42 on the center drum side.

(1) First, a ply assembly 48 is prepared in which a raw inner liner 18A is attached to and integrated with a raw carcass ply 30A.
(2) The ply assembly 48 is wound around the outer peripheral surfaces of the center drum 40 and the side drum 42 which are reduced in diameter as shown in FIG. 2 with the inner liner 18A facing the drum.

(3) Next, as shown in FIG. 3, the diameter of the center drum 40 is expanded, and the bead cores 12 are inserted from both sides.

Further, the ply cord of the carcass ply 30 is coated on the outer peripheral surface of the carcass ply 30A, specifically, the portion to be the main body 30B and the portion to which the ply end 30E of the folded portion 30A to be folded first is attached. A raw reinforcing rubber layer 32A made of the same rubber as the coating rubber is pasted. The ply end 30E and the raw reinforcing rubber layer 32A are pasted so as to coincide with the center in the width direction.
The width L of the raw reinforcing rubber layer 32A applied here is 0.3 to 1.1 times the overlap amount OLW shown in FIG. 1 at the portion where one folded portion 30A and the other folded portion 30A overlap. Is preferable, and the range of 0.5 to 0.9 times is more preferable.
Further, the gauge of the raw reinforcing rubber layer 32A to be attached is preferably in the range of 0.3 to 0.8 times the diameter of the ply cord (not shown) of the carcass ply 30; More preferably, it is in the range of 6 times.

(4) Next, as shown in FIG. 4, the diameter of the side drums 42 on both sides is increased so that the outer diameter is larger than that of the center drum 40, and one side drum 42 is moved to the center drum 40 side. As a result, one side of the ply assembly 48 abuts against the spring 46 of the side drum 42 and is folded back toward the other side drum 42 side.
When the ply assembly 48 is folded back, the diameter of the ply assembly 48 does not change greatly, and the spring 46 rotates and the ply assembly 48 moves (that is, the ply assembly 48 does not rub). Therefore, a large resistance is not given to the ply assembly 48.
After the folding of one side of the ply assembly 48 is completed, the side drum 42 is returned to the original position.

(5) Next, as shown in FIG. 5, the other side drum 42 is moved to the center drum side. As a result, the other side of the ply assembly 48 is folded back as shown in FIG. 6, and the folded portion is overlapped, that is, overlapped with the previously folded portion. After the other folding of the ply assembly 48 is completed, the side drum 42 is returned to its original position.

(6) After the side rubber 28 and the tread rubber 22 are attached to the outer peripheral surface of the ply assembly 48, the side rubber 28 and the tread rubber 22 are removed from the tire molding drum 44 and vulcanized with a mold as before.

  When the green tire thus obtained is vulcanized and molded, the angle of the ply cord of the carcass ply 30 is changed along with the diameter expansion of the green tire, and the ply end 30E moves to the folding side, so The rubber flows and the inner liner 18A in the vicinity of the ply end 30E tends to be drawn toward the ply end 30E. In this embodiment, the reinforcing rubber layer 32 is disposed between the ply end 30E and the main body 30B in advance. Therefore, the inner liner 18A is suppressed from being pulled toward the ply end 30E, and the decrease in the gauge of the inner liner 18A near the ply end 30E is suppressed.

  In the emergency bias tire 10 after vulcanization (see FIG. 1), the gauge of the inner liner 18 is constant, so that the deterioration of durability with time due to non-uniformity of the gauge of the inner liner 18 is suppressed. It is done. The amount of the reinforcing rubber layer 32 used is also extremely small relative to the amount of rubber used in the entire tire, and the increase in tire weight is almost negligible. In the emergency bias tire 10 shown in FIG. 1, the gauge of the reinforcing rubber layer 32 is drawn thick for easy understanding of the gist of the invention, but in an actual product tire, the reinforcing rubber layer 32 and the carcass ply 30 are drawn. The boundary with the ply coating rubber is not understood, and the rubber flows, so that the gauge of the reinforcing rubber layer 32 is almost eliminated.

  Here, if the overlap amount OLW of the carcass ply 30 is less than 40% of the tread width TW, tire durability cannot be obtained. On the other hand, when the overlap amount OLW exceeds 90% of the tread width TW, separation from the ply end tends to occur, which grows and grows into a crack reaching the tread shoulder surface. In addition, the steering performance during traveling cannot be obtained sufficiently.

  Further, when the width L1 of the raw reinforcing rubber layer 32A to be pasted is less than 0.3 times the overlap amount OLW, it is difficult to obtain installation accuracy due to variations in shrinkage of the overlap portion during vulcanization. On the other hand, if the width L1 of the raw reinforcing rubber layer 32A to be pasted exceeds 1.1 times the overlap amount OLW, the performance improvement due to the provision of the raw reinforcing rubber layer 32A will reach its peak, and the amount of rubber used will increase. Tire weight and cost.

  Next, when the gauge of the raw reinforcing rubber layer 32A to be attached is less than 0.3 times the ply cord, the effect of preventing rubber flow cannot be obtained. On the other hand, when the gauge of the raw reinforcing rubber layer 32A to be pasted exceeds 0.8 times the diameter of the ply cord, the step amount at the end portion of the reinforcing rubber layer increases, so that air enters the step portion. Product defects such as entering will increase, and cost will increase.

  In addition, the gauge of the inner liner 18A used at the time of tire molding is preferably in the range of 0.6 to 2.0 mm. If the gauge of the inner liner 18A is less than 0.6 mm, it is insufficient to prevent air permeation, and if it exceeds 2.0 mm, it is more than necessary to prevent air permeation, and the tire weight is unnecessarily increased. End up.

  According to the manufacturing method of the present embodiment, since the gauge of the inner liner 18A is not made nonuniform during tire manufacture, the minimum necessary gauge can be used as the inner liner 18A.

  In the emergency bias tire 10 that is a product, the gauge of the inner liner 18 is thin (for example, 0.6 mm or less), and the “minimum gauge / maximum gauge” of the inner liner is measured. If it becomes above, it can judge indirectly from a product tire that it manufactured using the manufacturing method of the emergency bias tire of this invention.

[Test example]
In order to confirm the effect of the present invention, emergency bias tires were manufactured by the manufacturing method of the present invention and the conventional manufacturing method, and the manufactured emergency bias tires were compared.

The size of the manufactured emergency bias tire is T105 / 90D12 90M.
In the manufacturing method of the present invention, the gauge of the reinforcing rubber layer to be attached is 0.5 times the diameter of the ply cord, and the width of the reinforcing rubber layer to be attached is 0.7 times the overlap dimension OLW. Incidentally, the overlap dimension OLW (see FIG. 1) of the carcass ply is 52 mm.
On the other hand, the conventional manufacturing method is different from the manufacturing method of the present invention in that no reinforcing rubber layer is used at the time of tire molding.

After manufacturing the emergency bias tire, the tire mass was measured, the tire was dissected and the inner liner gauge was measured. In addition, the gauge measured four places on the circumference in one tire at substantially equal intervals. A 10-times magnifier was used for the gauge measurement.
The results are as described in Table 1 below. In the table, “tire mass (index)” is an index display in which each tire mass is measured and the mass of a tire manufactured by a conventional manufacturing method is taken as 100. The larger the value, the greater the mass.

  Also, in the table, “O / L end I / L GUM Ga / relative side I / L GUM Ga (index)” means the inner liner gauge inside the ply end of the inner folded part and the outer folded part. The value divided by the gauge of the inner liner on the inner side of the ply end is expressed as an index. The larger the index value, the smaller the gauge variation (decrease).

表１に示すように、本発明の製造方法で製造された応急用バイアスタイヤでは、インナーライナーのゲージのバラツキが大幅に抑えられていることが分かる。

As shown in Table 1, in the emergency bias tire manufactured by the manufacturing method of the present invention, it can be seen that the variation of the gauge of the inner liner is greatly suppressed.

It is sectional drawing along the tire rotating shaft of the emergency bias tire which concerns on one Embodiment of this invention. It is sectional drawing of the tire molding drum which affixed the ply assembly. It is sectional drawing of the tire molding drum which expanded the center drum. It is sectional drawing of the tire shaping | molding drum which has turned back one side of the ply assembly. It is sectional drawing of the tire shaping | molding drum which has turned the other side of the ply assembly. It is sectional drawing of the tire shaping | molding drum which complete | finished folding of the ply assembly.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Emergency bias tire 12 Bead core 14 Carcass 20 Tread part 20A Tread edge part 22 Tread rubber 30 Ply 32 Reinforcement rubber layer 32A Raw reinforcement rubber layer

Claims (3)

One carcass ply in which a plurality of organic fiber cords are arranged in a direction inclined with respect to the tire equatorial plane and continuously extending from one bead core to the other bead core is arranged around the bead core from the inside to the outside of the tire. A method of manufacturing an emergency bias tire in which folded and left and right folded carcass plies are overlapped at a crown portion of a carcass ply main body extending from one bead core to the other bead core,
A rubber layer is disposed between the carcass ply main body and the ply end of the folded carcass ply located on the inner side in the tire radial direction when the carcass ply attached to the outside of the inner liner is folded during tire molding. A manufacturing method of an emergency bias tire characterized by the above.   The rubber layer is the same rubber as the covering rubber covering the organic fiber cord of the carcass ply, the gauge is 0.3 to 0.8 times the diameter of the organic fiber cord, and the tire rotating shaft 2. The emergency bias tire according to claim 1, wherein the width when viewed in a cross section along the line is 0.3 to 1.1 times the width of the overlapping portion of the folded carcass ply. One carcass ply in which a plurality of organic fiber cords are arranged in a direction inclined with respect to the tire equatorial plane and continuously extending from one bead core to the other bead core is arranged around the bead core from the inside to the outside of the tire. An emergency bias tire in which folded and left and right folded carcass plies are overlapped at a crown portion of a carcass ply main body extending from one bead core to the other bead core,
A rubber layer is disposed between the carcass ply body portion and the ply end of the folded carcass ply located on the inner side in the tire radial direction when the carcass ply attached to the outside of the inner liner is folded during tire molding. A bias tire for emergency use.

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