JP6153852B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire having a structure in which a carcass ply is wound up from the outside in the tire width direction.

  Conventionally, as shown in Patent Documents 1 to 3 below, by rolling up the carcass ply from the outside in the tire width direction to the inside, the distribution of the tension applied to the carcass ply is changed, and the tension at a position that easily contributes to tire rigidity is reduced. There are known pneumatic tires that increase and improve steering stability performance.

  In the following Patent Document 1, the carcass layer has a single-layer structure, and is wound around the bead core from the outer side in the tire width direction, the end of the carcass layer is disposed on the inner side in the tire radial direction of the bead core, and the end of the carcass layer A pneumatic tire intended to improve the steering stability of the tire is shown by winding the portion from the turn-up position toward the outer side in the tire radial direction so as not to wrap the bead core.

  Patent Document 2 listed below discloses a tire whose purpose is to substantially reduce the frequency of occurrence of early tire breakage by winding a carcass ply around the bead core from the outside in the tire width direction to the inside.

  In the following Patent Document 3, the carcass ply passes through the tire outer surface side from the bead filler, and both ends of the ply are supported by being wound up from the outer side to the inner side with respect to the bead cores on both sides. A pneumatic radial tire that can contribute to weight reduction of the tire and maintain rigidity without degrading the performance of is shown.

JP 2007-131173 A JP 2002-513360 Gazette JP 7-315013 A

  However, in all of the known techniques disclosed in Patent Documents 1 to 3, since the carcass ply is in direct contact with the bead core, when the internal pressure is applied to the tire, the carcass is generated by tension. There is a problem that the ply and the bead core are rubbed and broken to deteriorate durability.

  The present invention provides a pneumatic tire having a structure in which the carcass ply is wound up from the outer side in the tire width direction to the inner side, and the durability is improved by suppressing distortion at the winding end of the carcass ply. is there.

The pneumatic tire according to claim 1 of the present invention is a pneumatic tire including a pair of left and right beads including a bead core and a bead filler, a carcass ply spanned over the bead core, and an inner liner. The ply is wound around the bead core from the outer side in the tire width direction to the inner side in the tire width direction, and a rubber chacher is disposed at least on the inner side in the tire width direction of the carcass ply winding end of the bead. A strain suppressing rubber portion is disposed on the inner surface of the carcass ply winding end portion so as to cover the carcass ply winding end portion, and the strain suppressing rubber portion is a rubber having a 100% modulus value higher than the 100% modulus value of the rubber chafer. Ri name than wood, the inner liner, the car It is arranged on the inner peripheral side of the splice and is wound around the bead core from the inner side in the tire width direction to the outer side in the tire width direction, and both end portions of the inner liner extend between the bead core and the carcass ply. and wherein the Rukoto such was.

  By configuring as described above, the winding end of the carcass ply is covered with a strain suppressing rubber part harder than the rubber chacher, and the carcass ply winding up end forms a distortion suppressing rubber part and a bead filler. Since it is in a state of being sandwiched by rubber, the separation at the winding end of the carcass ply is reduced and the separation is suppressed.

  In addition, in the structure of the said Claim 1, you may form a distortion suppression rubber part with the rubber material of the 100% modulus value equivalent to or less than the 100% modulus value of a bead filler. When configured in this way, the rubber balance gradually decreases in the order of the bead filler, the strain suppressing rubber portion, and the rubber chafer, so that the rigidity balance is stabilized and the strain at the winding end of the carcass ply is further reduced. Let

  In addition, the strain suppression rubber portion is arranged such that the lower end portion of the strain suppression rubber portion is inward in the tire radial direction from the upper end of the bead core, and the upper end portion of the strain suppression rubber portion is wound from the upper end of the bead core outward in the tire radial direction. It is good also as 2 times or more of winding height.

  When configured as described above, the strain suppressing rubber portion covers the carcass ply winding end and the strain suppressing rubber portion is sandwiched over a wide range from the inside in the tire radial direction to the outside by the rubber chafer and the bead filler. Thus, the distortion at the winding end of the carcass ply is further reduced.

Further, when configured as described above, since the carcass ply does not directly contact the bead core, the carcass ply and the bead core are not ruptured by rubbing, and durability is improved. Note that the inner liner is not necessarily arranged on the inner peripheral side of the carcass ply, and may be arranged on the innermost layer side in the tire width direction.

The pneumatic tire according to claim 2 of the present invention is characterized in that, in the configuration of claim 1, the bead filler is provided with a recess that accommodates the thickness of the distortion-suppressing rubber portion.

  In the case of the above configuration, even if the strain suppressing rubber portion is provided as described above, the shape of the inner surface of the tire is not changed, so that the concentration of the strain can be avoided and the separation of the winding end portion of the carcass ply is achieved. Can be suppressed. Moreover, even if the strain suppressing rubber portion is provided, the durability of the tire can be improved without increasing the weight.

  As described above, the pneumatic tire of the present invention is a pneumatic tire having a structure in which the carcass ply is wound around the bead core from the outer side in the tire width direction to the inner side in the tire width direction. Distortion at the winding end of the carcass ply can be suppressed because the distortion suppressing rubber part covering the winding end of the carcass ply made of a rubber material of% modulus value can be suppressed. Can be suppressed, and the durability of the pneumatic tire can be improved.

It is a general | schematic fragmentary sectional view of the pneumatic tire which concerns on Example 1 of this invention. It is the elements on larger scale of FIG.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the drawings.

  The outline of Example 1 is that the carcass ply is wound around the bead core from the outer side in the tire width direction to the inner side in the tire width direction, and the inner liner is wound around the bead core from the inner side in the tire width direction to the outer side in the tire width direction. The both ends of the inner liner extend between the bead core and the carcass ply, and a rubber chacher is arranged around the bead core.

  1 and 2 show Example 1, and a symbol T in the drawings indicates a pneumatic tire. The pneumatic tire T includes a tire tread 1, sidewalls 2, and beads 3. The tire tread 1 includes a belt, a belt reinforcement 1a, and a tread rubber 1b. The bead 3 includes a bead core 3a and a bead filler 3b made of hard rubber extending outward in the tire radial direction from the bead core 3a.

  Reference numeral 4 denotes an inner liner disposed on the inner surface of the tire, and is wound around the bead core 3a from the inner side in the tire width direction to the outer side in the tire width direction. Reference numeral 5 denotes a carcass ply, and the carcass ply 5 is disposed so as to straddle between the bead cores 3 a across the tire tread 1, the sidewalls 2, and the beads 3, and around the bead cores 3 a on the outer side in the tire width direction. Is wound inward in the tire width direction. In the inner liner 4, both end portions of the inner liner 4 extend between the bead core 3 a and the carcass ply 5 around the bead core 3 a.

  Reference numeral 6 denotes a rubber chacher, which is disposed around the bead core 3 a so as to cover the inner liner 4 and the carcass ply 5. Therefore, the inner liner 4 and the carcass ply 5 are not exposed on the surface of the bead 3 including their rolled-up ends 4a and 5a.

  Further, a distortion suppressing rubber portion 7 is disposed on the inner surface of the rubber chacher 6 on the carcass ply winding end portion 5a side so as to cover the carcass ply winding end portion 5a. The strain suppressing rubber portion 7 is formed of a rubber material having a 100% modulus value that is higher than the 100% modulus value of the rubber chafer 6 and equal to or less than the 100% modulus value of the bead filler 3b.

  Since the present embodiment is configured as described above, since the carcass ply 5 does not directly contact the bead core 3a, the carcass ply 5 and the bead core 3a do not break due to rubbing and the durability is improved. To do. Further, the winding end portion 5a of the carcass ply 5 is covered with the strain suppressing rubber portion 7 which is harder than the rubber chacher 6, and as shown in the figure, the carcass ply winding end portion 5a is made of the strain suppressing rubber portion 7 and the bead filler 3b. It will be in the state inserted | pinched by the highly rigid rubber | gum which forms. Therefore, the distortion at the winding end portion 5a of the carcass ply 5 is reduced, and the separation is suppressed. Furthermore, since the bead filler 3b, the strain suppressing rubber portion 7 and the rubber chacher 6 that sandwich the carcass ply winding-up end portion 5a are gradually lowered in the order, the rigidity balance is overall. Therefore, the distortion does not concentrate on the winding end portion 5a of the carcass ply 5, and the distortion is further reduced.

  Further, in the strain suppression rubber portion 7, the lower end portion 7 a of the strain suppression rubber portion 7 is positioned inward in the tire radial direction from the upper end 3 a ′ of the bead core, and the upper end portion 7 b of the strain suppression rubber portion 7 is from the upper end of the bead core. The carcass ply wound up outward in the tire radial direction is disposed at a position that is at least twice the winding height h. Accordingly, the strain suppressing rubber portion 7 covers the carcass ply winding end portion 5a, the strain suppressing rubber portion 7 is arranged over a wide range from the inside in the tire radial direction to the outside, and the strain suppressing rubber portion 7 is the rubber chain. Since it is sandwiched between the her 6 and the bead filler 3b and is covered widely from the inner side to the outer side in the tire radial direction including the carcass ply winding end portion 5a by the distortion suppressing rubber portion 7, the distortion at the winding end portion of the carcass ply Will be further reduced.

  Further, in this embodiment, the bead filler 3b is provided with a recess 3c. The concave portion 3c of the bead filler 3b has a capacity and capacity to accommodate the thickness of the distortion suppressing rubber portion 7. Since the strain suppression rubber portion 7 is fitted into the recess 3c of the bead filler 3b, even if the rubber strainer 7 is provided with the strain suppression rubber portion 7, the tire inner surface shape by this does not change. Therefore, concentration of distortion can be avoided, and separation of the winding end portion 5a of the carcass ply can be suppressed. Even if the strain suppressing rubber portion 5a is provided, the weight of the bead filler 3b is reduced by the amount of the concave portion 3c, so that the durability of the tire can be improved without increasing the weight.

  In the above embodiment, the inner liner 4 is disposed on the inner peripheral side of the carcass ply 5 and is wound around the bead core 3a from the inner side in the tire width direction to the outer side in the tire width direction. However, the arrangement of the inner liner is not limited to this, and the inner liner 4 is not necessarily arranged on the inner peripheral side of the carcass ply 5. You may arrange | position to the innermost layer side of a tire width direction.

  In the second embodiment, although not illustrated, the bead filler 3b in the first embodiment is not provided with the recess 3c, and the shape of the bead filler is not changed. Since the other configuration is the same as that of the first embodiment, a description thereof will be omitted.

  Even in such a configuration, since the distortion suppressing rubber portion 7 covers the winding end portion 5a of the carcass ply 5, the occurrence of separation at the winding end portion 5a of the carcass ply 5 can be suppressed. Durability can be improved.

[Comparison test]
Next, with respect to the pneumatic tire according to the present invention, a comparative test was performed on the above Examples 1 and 2 and the following Comparative Examples 1 and 2 under the following conditions. The results are shown in Table 1 below.

Test tire: 195 / 65R15 91H
Test item In order to evaluate durability, the running distance until the tire failed was measured by a test method based on FMVSS139. The result of Comparative Example 1 was evaluated as an index with the value of 100, and the greater the index, the better the durability.

[Configuration of Comparative Example 1]
The outline of the pneumatic tire of Comparative Example 1 is a configuration in which the distortion suppressing rubber portion 7 in Example 1 is not provided, and the other configuration is the same as that of Example 1.

[Configuration of Comparative Example 2]
The outline of the pneumatic tire of Comparative Example 2 is that in Example 1, the strain suppressing rubber portion 7 is formed of a rubber material having a modulus value 100% higher than that of the rubber chacher 6, but Comparative Example 2 is a strain suppressing rubber. The part is formed of a rubber material whose modulus value is 100% lower than that of the rubber chacher. Other configurations are the same as those in the first embodiment.

[Results of comparative test]
A configuration in which a distortion suppressing rubber portion made of a rubber material having a modulus value 100% lower than that of the rubber chacher is provided to cover the winding end portion of the carcass ply with respect to the pneumatic tire having a configuration in which the distortion suppressing rubber portion of Comparative Example 1 is not provided. The comparative example 2 improved the durability. In addition, the second embodiment of the configuration in which a distortion suppressing rubber portion made of a rubber material having a 100% modulus value higher than that of the rubber chacher is provided to cover the winding end portion of the carcass ply and the concave portion is not provided in the bead filler is as described above. Although the durability was improved as compared with Comparative Example 2, the durability was lower than that of Example 1 in which a concave portion was provided in the bead filler.

  From the above test results, the configuration in which the strain-suppressing rubber portion is provided and the winding end portion of the carcass ply is covered is more durable than the configuration in which the strain-suppressing rubber portion is not provided, and the strain suppressing rubber portion is wound up of the carcass ply. In the structure that covers the end, the strain suppression rubber part that has a 100% modulus value higher than that of the rubber chacher has a higher durability than the strain suppression rubber part that has a lower modulus value of 100% than that of the rubber chafer. In the configuration in which the winding end portion of the carcass ply is covered and the strain suppression rubber portion having a modulus value 100% higher than that of the rubber chacher is provided, the bead filler is provided with a recess, and the strain suppression rubber portion is accommodated in the recess. It has been found that the construction improves durability.

  In addition, although some embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

T ......... Pneumatic tire h ......... Carcass ply winding height 1 ......... Tread 1a ... Belt and belt reinforcement 1b ... Tread rubber 2 ......... Side wall 3 ......... Bead 3a ... Bead core 3a '... upper end 3b of bead core ... bead filler 3c ... bead filler recess 4 ... inner liner 4a ... inner liner winding end 5 ... carcass ply 5a ... carcass ply winding end 6 ... Rubber chafer 7 ..... Strain suppression rubber part 7a ... Lower end part 7b of strain suppression rubber part ... Upper end part of strain suppression rubber part

Claims (2)

In a pneumatic tire having a pair of left and right beads including a bead core and a bead filler, a carcass ply spanned over the bead core, and an inner liner,
The carcass ply is wound around the bead core from the outside in the tire width direction to the inside in the tire width direction,
A rubber chacher is disposed on the inner side in the tire width direction of at least the carcass ply winding end of the bead,
Distributing a strain suppressing rubber part to cover the carcass ply hoisting end on the inner surface of the rubber chacher on the carcass ply hoisting end side,
The distortion suppressing rubber portion, Ri name from rubber 100% modulus value higher than 100% modulus value of the rubber chafer,
The inner liner is arranged on the inner peripheral side of the carcass ply, and is wound around the bead core from the inner side in the tire width direction to the outer side in the tire width direction,
A pneumatic tire both end portions of the inner liner, and wherein the ing extending between the bead cores and the carcass ply. The pneumatic tire according to claim 1, wherein the bead filler is provided with a recess that accommodates the thickness of the distortion suppressing rubber portion .

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