JP4394463B2 - Pneumatic radial tire - Google Patents

Description

  The present invention relates to a pneumatic radial tire, and more particularly, to a pneumatic radial tire having a bead portion structure that can suppress the deviation of a carcass layer during manufacturing and maintain stable quality.

  In the pneumatic radial tire, the carcass layer is locked between a pair of left and right bead cores that serve to fit the wheel. As shown in FIG. In general, the portion 102 is wound around the bead core 104 so as to be folded back from the inner side to the outer side in the tire width direction. In such a conventional locking structure, the carcass layer is displaced outward in the tire radial direction with the lift of the carcass layer that occurs in the molding process during tire manufacture. Therefore, in the past, tires were manufactured in anticipation of such manufacturing deviations. However, in the conventional structure described above, the carcass layer has a large deviation and is unstable due to the influence of the environmental temperature at the time of tire production. As a result, the performance of the product tire becomes unstable.

  Incidentally, in JP-A-10-338002 (Patent Document 1), for the purpose of facilitating vulcanization molding and improving durability while ensuring steering stability, the end of the carcass layer is provided. It has been proposed that the bead core is sandwiched from both sides between divided layers divided into a plurality of layers in the tire radial direction, and the tip thereof is bent and locked at the inner end of the divided layer holding region.

  Japanese Patent Application Laid-Open No. 11-28915 (Patent Document 2) describes a bead wire in the tire circumferential direction in order to reduce weight and improve uniformity and to increase the tightening force of the bead portion against the rim. The bead core is formed by continuously laminating and winding from the inner side to the outer side of the direction, and the bead wire is locked so that the end portion in the tire width direction of the carcass layer is sandwiched between the layers in the middle of the laminating and winding. Proposed.

Furthermore, in Japanese Patent Laid-Open No. 9-207526 (Patent Document 3), for the purpose of reducing road noise, a bead portion is disposed on the first bead core and a radially outer side of the tire via a buffer rubber layer. It is proposed that the carcass layer is configured to be folded back through between the second bead core and the shock absorbing rubber layer while being constituted by the second bead core.
JP 10-338002 A JP 11-28915 A JP-A-9-207526

  Compared with the conventional general structure shown in FIG. 4 by dividing the bead core into two upper and lower layers and sandwiching the end portion of the carcass layer between them as in Patent Document 1 and Patent Document 2 above, the carcass layer It is possible to reduce the displacement of the carcass layer during tire manufacture. However, in the structures disclosed in Patent Documents 1 and 2, the end portion of the carcass layer sandwiched between the bead cores divided vertically is terminated at the sandwiching portion and does not have a further winding portion. For this reason, it is not yet satisfactory in terms of preventing the displacement of the carcass layer. Moreover, in the said patent document 3, since the edge part of a carcass layer is hold | maintained between bead cores via the buffer rubber layer, the shift | offset | difference of a carcass layer at the time of tire manufacture cannot fully be reduced.

  The present invention has been made in view of the above points. A pneumatic radial tire that can suppress the deviation of the carcass layer at the time of manufacturing the tire and ensure stable tire quality, as compared with the prior art. The purpose is to provide.

A pneumatic radial tire according to a first aspect of the present invention includes a pair of left and right annular bead cores, a carcass layer whose ends are locked by the bead cores, and a bead filler disposed on a radially outer periphery of the bead core. The bead core includes an upper first layer and a lower second layer that are divided in the tire radial direction, and an end portion of the carcass layer includes the first layer and the second layer. The upper and lower surfaces are sandwiched between the first layer and the second layer, and the leading end is wound up outward in the tire radial direction, and the rolled up end is outside the tire radial direction of the bead filler. The carcass layer sandwiched between the first layer and the second layer is terminated before the end, and the sandwiched portion of the carcass layer is located on the tire radial direction inner side in the tire radial direction with respect to the tire rotation axis. Tilt to It is what was kicked.

A pneumatic radial tire according to claim 2 is an air including a pair of left and right annular bead cores, a carcass layer whose ends are locked by the bead cores, and a bead filler disposed on a radially outer periphery of the bead core. In the tire, the bead core includes an upper first layer and a lower second layer that are divided in the tire radial direction, and an end portion of the carcass layer is between the first layer and the second layer. with threaded with both the upper and lower surfaces is held between these first and second layers are inserted between the leading end is wound so as to wrap the first layer and the first layer and the bead filler The sandwiching portion of the carcass layer sandwiched between the first layer and the second layer is provided to be inclined with respect to the tire rotation axis so that the outer side in the tire width direction is the inner side in the tire radial direction. is there.

  In the pneumatic radial tire according to claim 1 of the present invention, the end portion of the carcass layer is formed by sandwiching the end portion of the carcass layer between the first layer and the second layer divided above and below the bead core. The position of the part can be stabilized. Moreover, in the present invention, since the end portion of the sandwiched carcass layer is further wound outward in the tire radial direction, when the tire is manufactured, when the tension in the tire radial direction outward acts on the carcass layer, A force to rotate is generated in the first layer on the upper side of the bead core wound by the carcass layer, and the clamping force between the lower second layer is increased, so that the end of the carcass layer is more firmly Fixed. Therefore, the deviation of the carcass layer in the tire production can be further reduced compared to the conventional case, and the variation during the production can be suppressed and the stable tire quality can be ensured.

  The pneumatic radial tire according to claim 2 also has basically the same effects as those of claim 1. Further, in the case of claim 2, since the end portion of the carcass layer sandwiched between the bead cores is rolled up so as to wrap the first layer and inserted between the first layer and the bead filler, The rotational force of the first layer acts more effectively, and the end of the carcass layer can be fixed more firmly.

  Hereinafter, a pneumatic radial tire according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a half sectional view of a pneumatic radial tire 10 according to a first embodiment (reference example) of the present invention. The tire 10 includes a pair of left and right bead portions 12 and sidewall portions 14, and a tread portion 16 that extends between the sidewall portions 14. Reference numeral 8 denotes a wheel rim.

  The bead portion 12 is provided with an annular bead core 18 formed by winding a bead wire in the tire circumferential direction, and a rubber bead filler 20 is disposed on the outer periphery in the radial direction of the bead core 18. The bead filler 20 has a substantially triangular cross section extending in a tapered shape from the outer surface in the radial direction of the bead core 18 toward the outer side in the tire radial direction. Between the pair of left and right bead cores 18, there is provided a carcass layer 22 formed of at least one carcass ply formed by extending a large number of cords arranged at right angles to the tire circumferential direction. Both ends of the are locked by bead cores 18. A belt 24 is disposed outside the carcass layer 22 in the tread portion 16 in the radial direction. The belt 24 is positioned on the outer surface in the radial direction of the crown portion of the carcass layer 22, and at least two belt plies in which non-extensible cords are inclined at a shallow angle with respect to the tire circumferential direction are overlapped so that the cords intersect each other. It becomes.

  In this embodiment, in the present embodiment, the bead core 18 is divided into a first layer 30 on the upper side (that is, the outer side in the tire radial direction) divided vertically in the tire radial direction, and a lower side (that is, the tire diameter). It has a two-layer structure with the second layer 32 on the inner side in the direction. In addition, the wire material and the number of the bead wires constituting the first layer 30 and the second layer 32 are the same in the example of FIG.

  In the present embodiment, the end portion of the carcass layer 22 is passed between the first layer 30 and the second layer 32 of the bead core 18, and the upper and lower surfaces thereof are directly formed by the first layer 30 and the second layer 32. In other words, it is sandwiched between the lower surface of the first layer 30 and the upper surface of the second layer 32. And the front-end | tip part 36 is wound up along the bead filler 20 rather than this clamping part 34, ie, the tire radial direction outward. More specifically, the winding portion 36 is wound from the inner side to the outer side in the tire width direction, and the side surface (outer side surface) of the first layer 30 and the bead filler 20 so as to wind up the first layer 30 of the bead core. It winds up in the state contact | abutted to these along the side surface (outer surface). Moreover, the upper end of the winding portion 36, that is, the winding end 36 </ b> A ends before the tire radial direction outer end 20 </ b> A of the bead filler 20.

  In the pneumatic radial tire 10 of the present embodiment configured as described above, the carcass layer 22 is obtained by the sandwiching effect caused by sandwiching the end portion of the carcass layer 22 between the first layer 30 and the second layer 32 of the bead core. The position of the end of the can be stabilized.

  In addition, since the end portion of the sandwiched carcass layer 22 is further wound outward in the tire radial direction, when the tension T outward in the tire radial direction acts on the carcass layer 22 during tire manufacture, 1, the first layer 30 of the bead core 18 that is wound by the carcass layer 22 has a tire width direction outer side portion on the winding side downward with respect to a tire width direction inner side portion on the non-winding side. A force F to rotate is generated. By this force F, the sandwiching portion 34 of the carcass layer 22 is more firmly sandwiched between the lower second layer 32, that is, between the upper first layer 30 and the lower second layer 32. Increased clamping force. Therefore, the end portion of the carcass layer 22 is more firmly fixed, and therefore, the displacement of the carcass layer in the tire manufacturing can be reduced more than before, and the variation in the manufacturing can be suppressed to ensure the stable tire quality. can do.

  The winding end 36 </ b> A of the carcass layer 22 is terminated before the upper end 20 </ b> A of the bead filler 20. If the bead filler 20 is completely wrapped by the carcass layer 22, the tension T is applied to the carcass layer 22. This is because, when acted, the hoisting part 36 is also lifted upward together, and the rotational force F cannot be obtained.

FIG. 2 shows a modification of the first embodiment described above. In the example shown in FIG. 1, the bead core 18 is divided substantially parallel to the tire rotation axis direction, and accordingly, the clamping portion 34 held between the upper and lower two layers of the bead core 18 is arranged substantially parallel to the tire rotation axis direction. However, the clamping part 34 can also be provided in a state inclined with respect to the tire rotation axis direction. FIGS. 2A and 2B show examples thereof. In the example of FIG. 2A, the sandwiching portion 34 is inclined by a predetermined angle α with respect to the tire rotation axis direction X so that the outer side in the tire width direction is the outer side in the tire radial direction. FIG. 2B relates to the embodiment , and the clamping portion 34 is inclined by a predetermined angle β with respect to the tire rotation axis direction X so that the outer side in the tire width direction is the inner side in the tire radial direction.

  In the example of FIG. 1 described above, the first layer 30 and the second layer 32 of the bead core 18 have the same number of bead wires and wires as the first layer 30 and the second layer 32. It may be different for layer 32. FIG. 2 (c) is an example in which the first layer 30 and the second layer 32 are the same wire material but have different numbers. In this example, the lower second layer 32 is on the upper side. The number is set smaller than that of the first layer 30. FIG. 2D shows an example in which the first layer 30 and the second layer 32 have the same number of wires but different wires. In this example, the first layer 30 and the second layer 32 depend on the lower second layer 32. A thick wire is used. Further, FIG. 2 (e) is an example in which the number and the wire are different between the first layer 30 and the second layer 32. In this example, a thick wire although the number of the second layer 32 is smaller. I use it.

FIG. 3A is an enlarged sectional view of a main part of a pneumatic radial tire according to a second embodiment (reference example) of the present invention. In the second embodiment, the configuration of the winding end of the carcass layer 22 after being sandwiched between the upper and lower two layers 30 and 32 of the bead core 18 is different from that of the first embodiment.

  That is, in this embodiment, both end portions of the carcass layer 22 are passed between the first layer 30 and the second layer 32 of the bead core and sandwiched there, and then the tip portion 38 wraps around the first layer 30. Is inserted between the upper surface of the first layer 30 and the lower surface of the bead filler 20, and the tip portion 38 is sandwiched between the first layer 30 and the bead filler 20. More specifically, the end portion of the carcass layer 22 wraps around the first layer 30 of the bead core by being rolled up from the inner side to the outer side in the tire width direction along the surface of the first layer 30 of the bead core. Other configurations are the same as those of the first embodiment described above, and thus description thereof is omitted.

  With this configuration, the effect of sandwiching the end portion of the carcass layer 22 between the two layers of the bead core 18 is exerted as in the first embodiment, and tension is applied to the carcass layer 22 during tire manufacture. At this time, a force to rotate is generated in the first layer 30 of the bead core wound around the carcass layer 22, thereby amplifying the sandwiching effect and fixing the carcass layer 22 more firmly. In addition, in the present embodiment, since the first layer 30 is enclosed by the carcass layer 22, the rotational force of the first layer 30 is more effectively applied, and the sandwiching effect is amplified. Furthermore, according to the present embodiment, the winding end 38 of the carcass layer 22 is also sandwiched between the first layer 30 and the bead filler 20 made of high-hardness rubber. Fixing can be further strengthened.

FIGS. 3B to 3F show modified examples of the second embodiment. FIGS. 3B and 3C are similar to FIGS. 2A and 2B, respectively. The sandwiching portion 34 sandwiched between the upper and lower two layers of the bead core 18 is provided in an inclined state with respect to the tire rotation axis direction. That is, in the example of FIG. 3B, the clamping portion 34 is inclined at a predetermined angle α with respect to the tire rotation axis direction X so that the outer side in the tire width direction is the outer side in the tire radial direction . FIG. 3C relates to the embodiment , and the sandwiching portion 34 is inclined by a predetermined angle β with respect to the tire rotation axis direction X so that the outer side in the tire width direction is the inner side in the tire radial direction.

  3 (d) to (f), the number of bead wires constituting the first layer 30 and the second layer 32 of the bead core 18 and / or the number of bead wires and / or the same as in FIGS. 2 (c) to (e). The wire is different. That is, FIG. 3D is an example in which the first layer 30 and the second layer 32 are the same wire material but have different numbers. In this example, the lower second layer 32 is the same. The number is set to be smaller than that of the upper first layer 30. FIG. 3E shows an example in which the first layer 30 and the second layer 32 have the same number of wires but different wires. In this example, the first layer 30 and the second layer 32 depend on the lower second layer 32. A thick wire is used. Further, FIG. 3 (f) is an example in which the number and the wire are different between the first layer 30 and the second layer 32. In this example, the second layer 32 has a smaller number but the thick wire. I use it.

As Example 1 (Reference Example) , pneumatic radial tires having a cross-sectional structure shown in FIG. 1 were produced with N = 5 tire sizes of 195 / 65R15. Further, as Example 2 (reference example) , N = 5 pneumatic radial tires having the bead structure shown in FIG. 3A and the other structures and sizes similar to Example 1 were produced. Further, as a comparative example, N = 5 pneumatic radial tires having the conventional bead portion structure shown in FIG. 4 and the other structures and sizes similar to those of Example 1 were produced.

For each tire of Example 1, Example 2 and Comparative Example, the amount of deviation of the carcass ply in the product tire from the green tire was measured, the average value of 5 pieces was obtained, and the average value of the comparative example was set to 100 The amount of deviation of the carcass ply was evaluated using an index. Further, for each of Example 1, Example 2 and Comparative Example, the deviation of the deviation amount between the five tires (difference between the largest deviation and the smallest deviation) was obtained, and the deviation of the comparative example was 100. The variation in the amount of misalignment of the carcass ply was evaluated using the index display. Furthermore, for each of Example 1, Example 2 and Comparative Example, tire lateral stiffness with 5 tires (air pressure of 230 kPa, load of 400 kg, lateral force of 100 kg is applied, and the lateral force is applied. Calculated by dividing by the amount of lateral deflection at the time of measurement), and the variation of the tire lateral stiffness was evaluated by an index display with the variation of the comparative example as 100. The results are shown in Table 1, respectively.

As shown in Table 1, when a structure in the actual Example 1 and 2, the amount of deviation of the carcass ply during tire manufacture are greatly reduced compared with the conventional structure, also, less the variation, therefore, Variations in quality such as tire stiffness could be greatly reduced.

1 is a half sectional view of a pneumatic radial tire according to a first embodiment (reference example) . (B) the Ri sectional view showing a bead portion structure of a pneumatic radial tire according to the embodiment, (a) and (c) ~ (e) is Ru Reference Example der. (C) the Ri sectional view showing a bead portion structure of a pneumatic radial tire according to another embodiment, (a), (b) and (d) ~ (f) is Ru Reference Example der. It is sectional drawing which shows the bead part structure of the conventional pneumatic radial tire.

Explanation of symbols

10. Pneumatic radial tire 18 ... Bead core 20 ... Bead filler 22 ... Carcass layer 30 ... First layer of bead core 32 ... Second layer of bead core 34 ... Nipping part 36 ... Winding part 36A ... Winding end 38 …… Turn-up tip

Claims (2)

In a pneumatic tire comprising a pair of left and right annular bead cores, a carcass layer whose ends are locked by the bead cores, and a bead filler disposed on a radially outer periphery of the bead core,
The bead core is composed of an upper first layer and a lower second layer divided in the tire radial direction,
The end portion of the carcass layer is passed between the first layer and the second layer, the upper and lower surfaces are sandwiched between the first layer and the second layer, and the tip thereof is wound up outward in the tire radial direction. And the hoisting end is terminated before the outer end in the tire radial direction of the bead filler ,
The sandwiching portion of the carcass layer sandwiched between the first layer and the second layer is provided so as to be inclined with respect to the tire rotation axis so that the outer side in the tire width direction is the inner side in the tire radial direction. Pneumatic radial tire. In a pneumatic tire comprising a pair of left and right annular bead cores, a carcass layer whose ends are locked by the bead cores, and a bead filler disposed on a radially outer periphery of the bead core,
The bead core is composed of an upper first layer and a lower second layer divided in the tire radial direction,
The end portion of the carcass layer is passed between the first layer and the second layer so that both upper and lower surfaces are sandwiched between the first layer and the second layer, and the tip thereof wraps around the first layer. Rolled up and inserted between the first layer and the bead filler ;
The sandwiching portion of the carcass layer sandwiched between the first layer and the second layer is provided to be inclined with respect to the tire rotation axis so that the outer side in the tire width direction is the inner side in the tire radial direction. A featured pneumatic radial tire.

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