JP2009179296A - Pneumatic tire - Google Patents

Pneumatic tire Download PDF

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Publication number
JP2009179296A
JP2009179296A JP2008022652A JP2008022652A JP2009179296A JP 2009179296 A JP2009179296 A JP 2009179296A JP 2008022652 A JP2008022652 A JP 2008022652A JP 2008022652 A JP2008022652 A JP 2008022652A JP 2009179296 A JP2009179296 A JP 2009179296A
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JP
Japan
Prior art keywords
tire
reinforcing layer
layer
steel
organic fiber
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Pending
Application number
JP2008022652A
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Japanese (ja)
Inventor
Shoji Tamura
将司 田村
Original Assignee
Yokohama Rubber Co Ltd:The
横浜ゴム株式会社
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Publication date
Application filed by Yokohama Rubber Co Ltd:The, 横浜ゴム株式会社 filed Critical Yokohama Rubber Co Ltd:The
Priority to JP2008022652A priority Critical patent/JP2009179296A/en
Publication of JP2009179296A publication Critical patent/JP2009179296A/en
Pending legal-status Critical Current

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Abstract

To provide a pneumatic tire capable of suppressing the occurrence of separation at a tire inner end portion of a steel reinforcing layer and improving durability.
Both end portions 2E of a carcass layer 2 extending between left and right bead portions 1 are folded back around the bead core 3 embedded in the left and right bead portions 1 from the inner side to the outer side in the tire axial direction. (2) A pneumatic tire in which a steel reinforcing layer 6 disposed on the outer side extends around the bead core 3 from the outer side to the inner side so as to be folded back from the outer side in the tire axial direction. An organic fiber reinforcing layer 7 is embedded so as to cover the tire inner end 6X of the steel reinforcing layer 6 from the tire inner surface side.
[Selection] Figure 1

Description

  The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire that is improved in durability.

  Since pneumatic tires used for trucks and buses are used under conditions of high load and high internal pressure, damage is likely to occur particularly at the bead portion in contact with the rim. As a countermeasure against this, the steel reinforcement layer with steel cords arranged on the bead part is arranged to reinforce the bead part, thereby increasing the durability of the bead part, and the same is achieved by retreading even if the tread part is worn out to the end of its service life. The tire can be recycled and used twice or more (for example, see Patent Document 1).

However, when used under severe conditions such as higher loads and higher loads, the amount of rolling of the vehicle to the left and right increases, resulting in a very large amount of tire deflection from the bead portion to the sidewall portion. In particular, as a result of large expansion and contraction deformation on the inner surface side of the tire, there is a problem that stress concentration is caused at the tire inner end portion of the steel reinforcing layer, and separation easily occurs at that portion.
JP-A-6-183224

  An object of the present invention is to provide a pneumatic tire capable of suppressing the occurrence of separation at the tire inner end portion of the steel reinforcing layer and improving the durability.

  The pneumatic tire of the present invention that achieves the above object is configured to bend back from the inner side to the outer side in the tire axial direction around a bead core in which both end portions of a carcass layer extending between the left and right bead portions are embedded in the left and right bead portions. In a pneumatic tire in which a steel reinforcing layer in which steel cords are arranged is arranged on the outer side of the carcass layer, and the steel reinforcing layer extends from the tire outer side to the inner side so as to be folded around the bead core from the outer side in the tire axial direction. An organic fiber reinforcing layer in which organic fiber cords are arranged is embedded in the tire so as to cover the tire inner end of the steel reinforcing layer from the tire inner surface side.

  According to the present invention described above, since the reinforcement is performed by covering the tire inner end of the steel reinforcing layer with the organic fiber reinforcing layer, the movement of the tire inner end portion of the steel reinforcing layer can be suppressed. Therefore, the stress concentrated on the tire inner end of the steel reinforcing layer can be relieved to prevent the occurrence of separation at that location, and the durability can be improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  1 and 2 show an embodiment of a pneumatic tire of the present invention, and 1 is a bead portion. A single carcass layer 2 in which steel cords Sc extending in the tire radial direction are arranged at predetermined intervals in the tire circumferential direction and embedded in the rubber layer is extended between the left and right bead portions 1. Both end portions 2E of the carcass layer 2 are folded back from the inner side to the outer side in the tire axial direction so as to sandwich the bead filler 4 around the bead cores 3 embedded in the left and right bead portions 1. The carcass layer 2 is not limited to one layer, and two or more layers may be arranged.

  Inside the carcass layer 2, a single inner liner layer 5 that acts as an air permeation preventive layer is disposed. The inner liner layer 5 extends between the left and right bead portions 1. A plurality of belt layers (for example, four layers for tires for trucks and buses) are disposed on the outer peripheral side of the carcass layer 2 in a tread portion (not shown).

  Steel reinforcement Sc embedded in the rubber layer is arranged on the outer side of the carcass layer 2 of each bead portion 1 at a predetermined interval in the tire circumferential direction with steel cords Sc that extend obliquely toward one side with respect to the tire circumferential direction. The layer 6 is arranged in an annular shape adjacent to the carcass layer 2. The steel reinforcing layer 6 extends from the tire outer side to the inner side so as to be folded around the bead core 3 from the outer side in the tire axial direction. The steel reinforcing layer 6 is such that the tire inner end 6X is located on the outer side in the tire radial direction from the end 2X of the carcass layer 2, while the tire outer end 6Y is located on the inner side in the tire radial direction from the end 2X of the carcass layer 2. It extends to.

  A single layer of organic fiber reinforcement layer 7 in which organic fiber cords fc extending incline toward the other side with respect to the tire circumferential direction are arranged at predetermined intervals in the tire circumferential direction and embedded in the rubber layer is a steel reinforcement layer 6. The tire inner terminal 6X is embedded in an annular shape in the tire so as to cover the inner surface of the tire. The organic fiber reinforcement layer 7 laminated on the steel reinforcement layer 6 has the organic fiber cord fc intersecting with the steel cord Sc of the steel reinforcement layer 6 with the inclination direction with respect to the tire circumferential direction being reversed, thereby providing a reinforcement effect. It is increasing.

  The organic fiber reinforcing layer 7 extends between the inner liner layer 5 and the steel reinforcing layer 6 from the position radially inward of the tire reinforcing layer 6 to the tire inner end 6X from the tire inner end 6X of the steel reinforcing layer 6, and the tire inner end 6X. Extends between the inner liner layer 5 and the carcass layer 2 from the tire radial direction outer side position.

  The height of the rim flange, which is the height from the inner peripheral end of the bead core 3 when the pneumatic tire (bead part 1) is mounted on the rim R, is FH, and from the inner peripheral end of the bead core 3 to the terminal 2X of the carcass layer 2 If the length in the tire radial direction is PH and the length in the tire radial direction from the inner peripheral end of the bead core 3 to the tire inner end 6X of the steel reinforcing layer 6 is SH, the relationship of FH <PH <SH is satisfied. .

  In FIG. 1, reference numeral 8 denotes an edge cover layer in which organic fiber cords are arranged to cover the end 2 </ b> X of the carcass layer 2 and the tire outer end 6 </ b> Y of the steel reinforcing layer 6, and both ends 2 </ b> X from the inner peripheral side of the bead core 3. , 6Y. 9 is a chafer rubber layer disposed on the bead portion 1, 10 is a rim cushion rubber layer, and 11 is a side rubber layer.

  According to the present invention described above, the organic fiber reinforcing layer 7 is reinforced so as to cover the tire inner end 6X of the steel reinforcing layer 6, so that the movement of the steel reinforcing layer 6 at the location of the tire inner end 6X is suppressed. be able to. Therefore, since the stress concentrated on the tire inner end 6X of the steel reinforcing layer 6 is relieved, it is possible to improve the durability by suppressing the occurrence of separation at that location.

In the present invention, the length in the tire radial direction from the inner peripheral end of the bead core 3 to the tire inner end 6X of the steel reinforcing layer 6 is SH, and the tire diameter from the inner peripheral end of the bead core 3 to the outer peripheral end 7U of the organic fiber reinforcing layer 7 If the length in the tire radial direction length from the inner peripheral end of the bead core 3 to the inner peripheral terminal 7L of the organic fiber reinforcing layer 7 is HL, the following relationship should be satisfied.
5.0mm + SH ≦ HU ≦ 1.3SH
HL ≦ SH-5.0mm

  When the tire radial length HU is smaller than 5.0 mm + SH, it is difficult to effectively reinforce the tire inner end 6 </ b> X of the steel reinforcing layer 6 by the organic fiber reinforcing layer 7. Conversely, when it exceeds 1.3SH, separation tends to occur at the outer peripheral terminal 7U of the organic fiber reinforcing layer 7.

  Even if the tire radial length HL is larger than SH-5.0 mm, the tire inner end 6X of the steel reinforcing layer 6 cannot be effectively reinforced by the organic fiber reinforcing layer 7. The lower limit value of the tire radial direction length HL is preferably not less than the height FH of the rim flange.

  The position of the tire inner end 6X of the steel reinforcing layer 6 is from the end 2X of the carcass layer 2 to the outer side in the tire radial direction and from the inner peripheral end of the bead core 3 to a position 1.5 times the tire radial direction length PH. It should be in the range. When the tire inner end 6X of the steel reinforcing layer 6 is positioned on the inner side in the tire radial direction from the end 2X of the carcass layer 2, the end 2X portion of the carcass layer 2 is easily damaged by the falling of the bead portion 1, and the bead portion durability is reduced. To do. On the other hand, when the position exceeds 1.5 times, it is located on the side of the sidewall portion where the movement is large, so that cracks are likely to occur at the tire inner end 6X of the steel reinforcing layer 6.

  As the organic fiber cord fc of the organic fiber reinforcing layer 7, for example, a nylon cord, a polyester cord, an aromatic polyamide cord, a high tension vinylon cord or the like can be preferably used. The organic fiber cord fc of the organic fiber reinforcing layer 7 may have a plain weave structure or a braided weave structure. The number of the organic fiber cords fc arranged is preferably 20 to 40/50 mm from the viewpoint of the reinforcing effect. As the rubber used for the organic fiber reinforcing layer 7, it is preferable to use a rubber having the same degree of hardness as the rubber of the adjacent carcass layer 2 or the steel reinforcing layer 6, and the hardness is in the range of 60 to 70. be able to. In addition, the hardness said here is the hardness measured based on durometer type A of JISK6253.

  The organic fiber cord fc of the organic fiber reinforcement layer 7 that intersects the steel cord Sc of the steel reinforcement layer 6 has an inclination angle α with respect to the tire circumferential direction smaller than an inclination angle β of the steel cord Sc of the steel reinforcement layer 6 with respect to the tire circumferential direction. It is sufficient to enhance the reinforcing effect by enhancing the tagging effect. The inclination angle α of the organic fiber cord fc of the organic fiber reinforcing layer 7 can be in the range of 15 to 30 degrees. Further, the inclination angle β of the steel cord Sc of the steel reinforcing layer 6 can be in the range of 20 to 35 degrees.

  In the above embodiment, the organic fiber reinforcing layer 7 is provided with one layer, but may be provided with two layers as shown in FIG. In the case where two layers are provided in this manner, the two layers are laminated so that the organic fiber cords fc of the two-layer organic fiber reinforcing layer 7 cross each other with the inclination direction with respect to the tire circumferential direction reversed, thereby further enhancing the reinforcing effect. Above is good.

  The present invention can be preferably used for heavy-duty pneumatic tires used particularly for trucks and buses, but is not limited thereto. The tire radial length and the inclination angle in the above-described embodiment are set to 5 of the air pressure corresponding to the maximum load capacity specified in JATMA when the tire is mounted on an applicable rim specified in JATMA (YEAR BOOK 2007). It is the length and the inclination angle in the state where the internal pressure of% is filled.

  Tires 1 to 9 of the present invention having the configuration shown in FIG. 1 in which the tire size is the same for 1200R20 and the tire radial lengths HU and HL to both ends of the organic fiber reinforcing layer are as shown in Table 1 (Example 1) 9), a conventional tire (conventional example) without an organic fiber reinforcing layer, and a tire according to the present invention 1 were prepared as comparative tires (comparative examples) in which a reinforcing rubber layer was disposed in place of the organic fiber reinforcing layer.

  In the tires 1 to 9 of the present invention, interlaced nylon cords are used for the organic fiber cords of the organic fiber reinforcing layer, and the number of arrangement is 30/50 mm. A rubber having a hardness of 65 was used as the rubber for the organic fiber reinforcing layer. The inclination angle α of the organic fiber cord of the organic fiber reinforcing layer with respect to the tire circumferential direction is as shown in Table 1.

  In the comparative tire, rubber having a hardness of 65 was used for the reinforcing rubber layer. In each test tire, the inclination angle β of the steel reinforcing layer with respect to the tire circumferential direction of the steel cord is 30 degrees, the length SH in the tire radial direction to the tire inner end of the steel reinforcing layer is 70 mm, the height FH of the rim flange is 35 mm, The tire radial direction length PH to the end of the carcass layer is 55 mm and common.

  When the durability evaluation test was performed on each of the test tires by the method shown below, the results shown in Table 1 were obtained.

Durability Each test tire is mounted on a rim with a rim size of 20 × 8.50V, attached to a drum testing machine with an air pressure of 830 kPa, and run at a speed of 20 km / h under a load of 91.98 kN. Was increased by 5 km / h, and the distance traveled until the failure occurred was measured. The evaluation result is shown as an index value with the conventional tire as 100. The greater this value, the better the durability.

  Table 1 shows that the tire of the present invention can improve the durability.

It is principal part sectional drawing which shows one Embodiment of the pneumatic tire of this invention. It is perspective explanation which shows the relationship between a carcass layer, a steel reinforcement layer, and an organic fiber reinforcement layer. It is principal part sectional drawing which shows other embodiment of the pneumatic tire of this invention.

Explanation of symbols

1 bead portion 2 carcass layer 2E end 2X end 3 bead core 6 steel reinforcing layer 6X tire inner end 6Y tire outer end 7 organic fiber reinforcing layer 7L inner peripheral end 7U outer peripheral end R rim Sc steel cord fc organic fiber cord α, β inclined angle

Claims (5)

  1.   A steel reinforcement layer in which both ends of the carcass layer extending between the left and right bead portions are folded back from the inner side in the tire axial direction around the bead core embedded in the left and right bead portions, and steel cords are arranged on the outer side of the carcass layer of the bead portion. In a pneumatic tire that extends from the outside to the inside of the tire so that the steel reinforcing layer is folded from the outside to the inside in the tire axial direction around the bead core. A pneumatic tire embedded in a tire so as to cover the tire inner end of the reinforcing layer from the tire inner surface side.
  2. The length in the tire radial direction from the inner peripheral end of the bead core to the tire inner end of the steel reinforcing layer is SH, the tire radial length from the inner peripheral end of the bead core to the outer peripheral end of the organic fiber reinforcing layer is HU, the inner periphery of the bead core 2. The pneumatic tire according to claim 1, wherein the tire radial direction length from the end to the inner peripheral terminal of the organic fiber reinforcing layer is HL, and the following relationship is satisfied.
    5.0mm + SH ≦ HU ≦ 1.3SH
    HL ≦ SH-5.0mm
  3.   The steel cord of the steel reinforcement layer is arranged to be inclined to one side with respect to the tire circumferential direction, and the organic fiber cord of the organic fiber reinforcement layer is arranged to be inclined to the other side with respect to the tire circumferential direction. The pneumatic tire according to claim 1 or 2, wherein the organic fiber cord intersects with the steel cord of the steel reinforcing layer with an inclination direction with respect to the tire circumferential direction being reversed.
  4.   The pneumatic tire according to claim 3, wherein an inclination angle of the organic fiber cord of the organic fiber reinforcement layer with respect to the tire circumferential direction is smaller than an inclination angle of the steel cord of the steel reinforcement layer with respect to the tire circumferential direction.
  5.   The height FH of the rim flange, which is the height from the inner peripheral end of the bead core when the pneumatic tire is mounted on the rim, the tire radial length PH from the inner peripheral end of the bead core to the end of the carcass layer, and the bead core The pneumatic tire according to any one of claims 1 to 4, wherein a tire radial length SH from an inner peripheral end of the tire to a tire inner end of the steel reinforcing layer satisfies a relationship of FH <PH <SH.
JP2008022652A 2008-02-01 2008-02-01 Pneumatic tire Pending JP2009179296A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2008022652A JP2009179296A (en) 2008-02-01 2008-02-01 Pneumatic tire

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2008022652A JP2009179296A (en) 2008-02-01 2008-02-01 Pneumatic tire

Publications (1)

Publication Number Publication Date
JP2009179296A true JP2009179296A (en) 2009-08-13

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Family Applications (1)

Application Number Title Priority Date Filing Date
JP2008022652A Pending JP2009179296A (en) 2008-02-01 2008-02-01 Pneumatic tire

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Country Link
JP (1) JP2009179296A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011013796A1 (en) 2009-07-31 2011-02-03 クラリオン株式会社 Navigation device, program, and display method
US8701729B2 (en) 2011-01-26 2014-04-22 Toyo Tire & Rubber Co., Ltd. Pneumatic radial tire

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011013796A1 (en) 2009-07-31 2011-02-03 クラリオン株式会社 Navigation device, program, and display method
US8701729B2 (en) 2011-01-26 2014-04-22 Toyo Tire & Rubber Co., Ltd. Pneumatic radial tire

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