Design method for preventing the folding of the apex after laminating in all-steel radial truck tires

Abstract

The present invention relates to a design method for preventing the folding of the apex after being attached to the steel wire ring of a all-steel radial truck tire, belonging to the field of tire production. The aspect ratio L / H of the apex is ≤12. When the designed apex is an apex containing an upper apex part and a lower apex part: the stress relaxation time τ of the compound of the upper apex part is ≤10 s, the stress relaxation time τ of the compound of the lower apex part is ≤9 s, and the difference in stress relaxation time between the compound of the upper apex part and the compound of the lower apex part is ≤1 s. When the designed apex is an apex containing only a single apex part: the stress relaxation time τ of the compound of the single apex part is ≤8 s; the surface temperature T when the apex is attached to the steel wire ring is ≤45°C.

Description

Technical Field

[0001] The present invention belongs to the field of tire production, and more specifically, it is a design method for preventing the folding of the chafer after being bonded to the bead wire of a steel radial truck tire. Background Art

[0002] As is well known, there are mainly two ways to produce the chafer bead wire assembly of a steel radial truck tire. One way is to produce the chafer on the extruder line, cut it, and then use the assembly forming drum to bond the bead wire and the cut chafer. The other way is to directly produce the assembly using a hot-bonding production line that combines an extruder, a conveying auxiliary line, and a bonding drum. And there are three bonding methods: horizontal disk type, vertical bladder reverse wrapping type, and vertical mechanical reverse wrapping type. No matter which way is used to produce the assembly and which bonding method is used, there will be a phenomenon that the chafer folds after being bonded to the bead wire.

[0003] If the chafer folds, the following phenomena will occur:

[0004] (1) When forming the tire blank, the bead wire cannot be properly positioned, and thus cannot match the designed flat width and head width of the construction, resulting in uneven height of the carcass and reinforcement layer reverse wrapping of the finished tire, and ultimately leading to usage problems.

[0005] (2) When forming the tire blank, the chafer cannot be compacted, resulting in air bubbles in the chafer area, increasing the repair difficulty. If the air bubbles are not completely repaired, cracks or delamination may occur in this area during the use of the finished tire. Or during forming, the edge of the chafer folds, resulting in uneven material distribution in this area of the finished tire and abnormal rigidity of the finished tire. Summary of the Invention

[0006] In order to overcome the deficiencies of the prior art, the present invention provides a design method for preventing the folding of the chafer after being bonded to the bead wire of a steel radial truck tire, which can effectively prevent the chafer from folding after being bonded to the bead wire, during the storage of the assembly, and during the forming of the tire blank.

[0007] The technical solution adopted by the present invention to solve its technical problems is: a design method for preventing the folding of the chafer after being bonded to the bead wire of a steel radial truck tire, characterized in that the aspect ratio L / H of the chafer ≤ 12; when the designed chafer is a chafer containing an upper chafer part and a lower chafer part: the stress relaxation time τ of the upper chafer part compound ≤ 10 s, the stress relaxation time τ of the lower chafer part compound ≤ 9 s, and the difference in stress relaxation time between the upper chafer part compound and the lower chafer part compound ≤ 1 s; when the designed chafer is a chafer containing only a single chafer part: the stress relaxation time τ of the single chafer part compound ≤ 8 s; the surface temperature T when the chafer is bonded to the bead wire ≤ 45 °C.

[0008] The beneficial effects of the present invention are as follows: it can effectively prevent the phenomenon of the apex strip from curling when it is bonded to the bead wire, during storage after bonding, and during use after storage, improve the smoothness of green tire forming, enhance the detection efficiency of the finished tire, and reduce the forming difficulty of the green tire and the failure rate of the finished tire caused by the curling of the apex strip. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The present invention will be further described below in conjunction with the drawings and embodiments.

[0010] Figure 1 It is a diagram showing the selection position of the aspect ratio for apex strip calculation.

[0011] Figure 2 It is a schematic diagram of the bonding of the apex strip and the bead wire. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0012] Embodiment 1:

[0013] Select an apex strip of 12.00R20 specification containing an upper apex strip part and a lower apex strip part. Select a hot bonding production line and a vertical mechanical reverse wrapping production fitting. After the fitting is stored for 4 hours, compare the apex strip curling rate between the fitting produced according to the requirements of this patent and the fitting produced conventionally. Requirements of this patent: the aspect ratio L / H value of the apex strip ≤ 12; the stress relaxation time τ of the rubber compound in the upper apex strip part ≤ 10 s, the stress relaxation time τ of the rubber compound in the lower apex strip part ≤ 9 s, and the stress relaxation time difference between the rubber compound in the upper apex strip part and the rubber compound in the lower apex strip part ≤ 1 s; the surface temperature T when the apex strip is bonded to the bead wire ≤ 45°C.

[0014]

[0015]

[0016] Embodiment 2:

[0017] Select an apex strip of 12.00R20 specification containing an upper apex strip part and a lower apex strip part. Select a cold production line and a vertical bladder reverse wrapping production fitting. After the fitting is stored for 4 hours, compare the apex strip curling rate between the fitting produced according to the requirements of this patent and the fitting produced conventionally.

[0018]

[0019] Embodiment 3:

[0020] Select a 12R22.5 specification apex rubber that only contains a single apex rubber part. Select a hot patch production line and a vertical mechanical reverse wrapping production method to produce the bonded part. After the bonded part is stored for 4 hours, compare the apex rubber folding rate of the bonded part produced according to the requirements of this patent with that of the conventionally produced bonded part. The requirements of this patent are: the aspect ratio L / H value of the apex rubber ≤ 12; the stress relaxation time τ of the single apex rubber compound ≤ 8 s; the surface temperature T when the apex rubber is bonded to the bead wire ≤ 45 °C.

[0021]

[0022] Example 4

[0023] Select a 12R22.5 specification apex rubber that only contains a single apex rubber part. Select a cold patch production line and a vertical bladder reverse wrapping production method to produce the bonded part. After the bonded part is stored for 4 hours, compare the apex rubber folding rate of the bonded part produced according to the requirements of this patent with that of the conventionally produced bonded part.

[0024]

[0025] The design method proposed in this patent can significantly reduce the ratio of folding that occurs after the apex rubber is bonded to the bead wire.

Claims

1. A design method for preventing the folding of the apex after laminating in all-steel radial truck tires, characterized in that, The aspect ratio L / H of the apex is ≤ 12, where L is the overall height of the apex and H is the width at 40%L from the outer end of the apex; when the designed apex is an apex with an upper apex part and a lower apex part: the stress relaxation time τ of the rubber compound in the upper apex part is ≤ 10 s, the stress relaxation time τ of the rubber compound in the lower apex part is ≤ 9 s, and the difference in stress relaxation time between the rubber compound in the upper apex part and the rubber compound in the lower apex part is ≤ 1 s. When the designed apex is an apex with only a single apex part: the stress relaxation time τ of the rubber compound in the single apex part is ≤ 8 s; the surface temperature T when the apex is in contact with the bead is ≤ 45 °C.

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