JP2018108754A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pneumatic tire which is high in rigidity and a mass of which does not become excessive.SOLUTION: The pneumatic tire has a winding-up end 19 of a carcass ply 16, arranged at an outer side in a tire radial direction than the tire maximum width position, and the tire maximum width position is arranged at an outer side in the tire radial direction than an end part 15 of a bead filler 14 at the outside in the tire radial direction. In the pneumatic tire, a reinforcement material 20 in which a plurality of cords are coated with rubber are arranged between the bead filler 14 and a winding-up part 18 of the carcass ply 16, an end part 22 of the reinforcement material 20 at the outside in the tire radial direction is arranged between the end part 15 of the bead filler 14 at the outside in the tire radial direction and the position of the tire maximum width, and cords 21 of the reinforcement material 20 and cords 17 of a body part 13 of the carcass ply 16 are arranged at the same angle.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a pneumatic tire.

  In a pneumatic tire, a carcass ply 116 in which a plurality of cords 117 (see FIG. 4 for a symbol) is covered with rubber is folded back from the inside in the tire width direction to the outside around the bead portion 110 and wound up outside in the tire width direction. ing. The carcass ply 116 is wound while the bead portions 110 are set on both sides in the axial direction of the cylindrical band body made of the carcass ply 116 and the like, and then the band body is rotated in the circumferential direction. As a result, as shown in FIG. 4, an angle is formed between the cord 117 in the winding portion 118 of the carcass ply 116 and the cord 117 in the main body portion 113 (a portion between the two bead portions 110) of the carcass ply 116. . If the angle is set in this way, the rigidity of the pneumatic tire may not be ensured.

  Therefore, for example, as described in Patent Document 1 and Patent Document 2, if a reinforcing layer including a cord is inserted in the bead portion or the vicinity thereof, it is considered that rigidity can be secured. However, if the insertion range of the reinforcing layer and the extension direction of the cord of the reinforcing layer are not defined, the mass of the pneumatic tire becomes heavy and the manufacturing cost may increase.

JP-A-5-270218 JP 2003-320819 A

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a pneumatic tire that has high rigidity and does not have an excessive mass.

  The pneumatic tire according to the embodiment includes a bead portion including a bead core and a bead filler provided on the outer side in the tire radial direction of the bead core on both sides in the tire width direction, and a carcass in which a plurality of cords extending in the radial direction are covered with rubber. The ply is folded around the two bead portions from the inside to the outside in the tire width direction and wound up, whereby the main body portion of the carcass ply between the two bead portions and both sides of the main body portion in the tire width direction A winding portion of the carcass ply is formed, a winding end of the winding portion is located on the outer side in the tire radial direction from the tire maximum width position, and the tire maximum width position is located on the tire outer side in the tire radial direction of the bead filler. In the pneumatic tire on the radially outer side, the bead filler and the winding portion A reinforcing material in which a plurality of cords are covered with rubber is provided between the ends of the reinforcing material in the tire radial direction between the end portion in the tire radial direction of the bead filler and the tire maximum width position. The cord of the reinforcing member and the cord of the main body portion are arranged at the same angle with respect to the tangential direction of the bead core.

  According to this embodiment, at the time of turn-up in the manufacture of a pneumatic tire, the cord of the carcass ply winding portion is along the cord of the reinforcing material, and the cord of the carcass ply winding portion and the main portion of the carcass ply The cord and the angle are almost the same, and the rigidity of the pneumatic tire is increased. Moreover, since the insertion range of the reinforcing material is limited, the mass of the pneumatic tire is not excessive.

FIG. 2 is a half sectional view of the pneumatic tire 1 in the tire width direction. The figure which looked at the carcass ply 16 and the reinforcing material 20 from the tire width direction outer side. The figure which shows the manufacturing method of the pneumatic tire. (A) The figure which shows formation of the band body 40. FIG. (B) The figure which shows the set of the bead part 10. FIG. (C) The figure which shows shaping and turn-up. (D) The figure which shows secondary molding. The figure which looked at the carcass ply 116 in the conventional pneumatic tire from the tire width direction outer side.

  This embodiment will be described with reference to the drawings. In addition, this embodiment is only an example and what was suitably changed in the range which does not deviate from the meaning of this invention shall be contained in the scope of the present invention. In addition, for convenience of explanation, the drawings may be drawn with exaggerated lengths or shapes, or may be drawn schematically.

  As shown in FIG. 1, the pneumatic tire 1 of the present embodiment includes bead portions 10 on both sides in the tire width direction. The bead portion 10 includes a bead core 12 and a bead filler 14 provided on the outer side in the tire radial direction of the bead core 12. Note that the upper end (end portion on the outer side in the tire radial direction) 15 of the bead filler 14 is located on the inner side in the tire radial direction with respect to the tire maximum width position 2.

  The carcass ply 16 is folded back from the inside in the tire width direction to the outside around the bead portion 10 on both sides in the tire width direction so as to wrap the bead portion 10. The carcass ply 16 folded back outward in the tire width direction is wound up outward in the tire radial direction. Thereby, a main body portion 13 formed of a portion between the two bead portions 10 of the carcass ply 16 and a winding portion 18 of the carcass ply 16 on the outer side in the tire width direction of the main body portion 13 are formed. The winding end 19 of the carcass ply 16 (the end portion on the outer side in the tire radial direction of the winding portion 18) reaches the outer side in the tire radial direction from the tire maximum width position 2. Further, the main body portion 13 of the carcass ply 16 forms a skeleton of the pneumatic tire 1.

  As shown in FIG. 2, the carcass ply 16 has a plurality of cords 17 covered with rubber. The cord 17 of the carcass ply 16 is made of, for example, an organic fiber. The organic fiber is, for example, a polyester fiber. The cord 17 in the main body portion 13 of the carcass ply 16 extends in the radial direction, and is disposed, for example, at an angle of 85 ° or more and 95 ° or less with respect to the tangential direction of the bead core 12. The tangential direction of the bead core 12 coincides with the tire circumferential direction.

  As shown in FIG. 1, a belt 30 in which a steel cord is covered with rubber is provided outside the carcass ply 16 in the tire radial direction. A belt reinforcing layer 31 covers the belt 30 from the outer side in the tire radial direction. A tread portion 32 having a ground contact surface is provided outside the belt reinforcing layer 31 in the tire radial direction.

  Further, side walls 33 are provided on both sides of the carcass ply 16 in the tire width direction. An inner liner 34 is provided inside the carcass ply 16. Further, a rubber chafer 35 is provided from the lower end of the sidewall 33 to the lower end of the inner liner 34 so as to wrap the bead portion 10 from the outside of the carcass ply 16.

  As shown in FIGS. 1 and 2, a reinforcing member 20 is provided between the bead filler 14 and the winding portion 18 of the carcass ply 16. The inner surface in the tire width direction of the reinforcing member 20 is in contact with the bead filler 14 on the inner side in the tire radial direction, and is in contact with the main body portion 13 of the carcass ply 16 on the outer side in the tire radial direction. Further, the outer surface of the reinforcing member 20 in the tire width direction is in contact with the winding portion 18 of the carcass ply 16. The upper end (end portion on the outer side in the tire radial direction) 22 of the reinforcing member 20 is between the upper end 15 of the bead filler 14 and the tire maximum width position 2 in the vertical direction. Further, it is desirable that the lower end (end portion on the inner side in the tire radial direction) 23 of the reinforcing member 20 is located at the position of the upper end (end portion on the outer side in the tire radial direction) 11 of the bead core 12 as illustrated.

  As shown in FIG. 2, the reinforcing member 20 is formed by covering a plurality of cords 21 with rubber. The cord 21 of the reinforcing member 20 is made of steel, for example. The thickness of the reinforcing material 20 is, for example, 1.05 mm or more and 1.70 mm or less. The rubber layer covering the cord 21 is thin, and the thickness of the reinforcing member 20 is mainly the thickness of the cord 21. As shown in FIG. 2, the cord 21 of the reinforcing member 20 extends in the same direction as the cord 17 in the side portion of the main body portion 13 of the carcass ply 16. In other words, the cord 21 of the reinforcing member 20 and the cord 17 in the side portion of the main body portion 13 of the carcass ply 16 are arranged at the same angle with respect to the tangential direction of the bead core 12. Here, the side portion of the main body portion 13 is a portion of the main body portion 13 that overlaps the reinforcing member 20 in the tire width direction. Further, the cord 21 of the reinforcing member 20 and the cord 17 of the side portion of the main body portion 13 specifically extend in the tire radial direction.

  Furthermore, it is desirable that the cord 21 of the reinforcing member 20 extends in the same direction as the cord 17 in the winding portion 18 of the carcass ply 16. In other words, the cord 21 of the reinforcing member 20 and the cord 17 in the winding portion 18 of the carcass ply 16 are desirably arranged at the same angle with respect to the tangential direction of the bead core 12.

  Here, when the number of ends of the cord 21 in the reinforcing material 20 is HE and the number of ends of the cord 17 in the winding portion 18 of the carcass ply 16 is PE, the relationship of 0.7PE ≦ HE ≦ 1.0PE may be satisfied. desirable. In particular, it is most desirable that HE = PE. The number of ends refers to the number of cords that are driven per 25 mm.

  A method for manufacturing the pneumatic tire 1 having the above structure will be described. The manufacturing process of the pneumatic tire 1 is roughly divided into primary molding, secondary molding, and vulcanization molding. FIG. 3 shows a simplified method for manufacturing the pneumatic tire 1.

  As shown in FIG. 3A, in the primary molding, first, the inner liner 34 and the carcass ply 16 are attached to the central portion of the molding drum D in the axial direction. Further, sidewalls 33 and the like are attached to the left and right sides of the molding drum D. As described above, the band body 40 including the carcass ply 16 and the sidewall 33 is formed.

  After the band body 40 is formed, the bead portions 10 are set at two places on the left and right sides of the band body 40 as shown in FIG. Next, as shown in FIG. 3C, the portion between the two bead portions 10 of the band body 40 is shaped in the outer diameter direction, and the portions on the left and right sides of the two bead portions 10 of the band body 40. Are turned up so as to enclose each bead portion 10. In FIG. 3C, an arrow S is a shaping direction, and an arrow T is a turn-up direction.

  Here, before the band body 40 is turned up, the reinforcing material 20 is attached to the outer surface of the bead filler 14 in the tire width direction. At this time, as illustrated in the left half of FIG. 2, the cord 21 of the reinforcing member 20 and the cord 17 of the main body portion 13 of the carcass ply 16 have the same angle with respect to the tangential direction of the bead core 12. Yes. When the reinforcing material 20 is turned up in this manner, the cord 17 of the winding portion 18 of the carcass ply 16 is attached to the reinforcing material 20 as illustrated in the right half of FIG. It is wound up along the cord 21 and the cord 17 of the main body portion 13 of the carcass ply 16. As a result, after the turn-up, the cord 17 of the winding portion 18 of the carcass ply 16 and the cord 17 of the main body portion 13 of the carcass ply 16 are at substantially the same angle with respect to the tangential direction of the bead core 12.

  A so-called green case 41 is obtained by shaping and turning up the band body 40 in this way. The primary molding is completed when the green case 41 is completed.

  Next, secondary molding is performed in which the belt 30, the belt reinforcing layer 31, and the tread portion 32 are attached to the outer diameter portion of the green case 41. Prior to the secondary molding, the belt 30, the belt reinforcing layer 31, and the tread portion 32 are laminated in advance to complete the tread body 43. In the secondary molding, the tread body 43 is attached to the outer diameter portion of the green case 41 as shown in FIG. A green tire 44 is formed by integrating the green case 41 and the tread body 43. When the raw tire 44 is completed, the secondary molding is completed.

  Next, vulcanization molding is performed. In vulcanization molding, the raw tire 44 is placed in a mold and held at a predetermined temperature for a predetermined time. When the vulcanization molding is finished, the pneumatic tire 1 is completed.

  The effect of this embodiment is as follows. First, as described above, the reinforcing member 20 is provided between the bead filler 14 and the winding portion 18 of the carcass ply 16, and the cord 21 of the reinforcing member 20 and the cord 17 of the main body portion 13 of the carcass ply 16 are connected to the bead core 12. Are arranged at the same angle with respect to the tangential direction. Therefore, at the time of turn-up in the manufacture of the pneumatic tire 1, the cord 17 of the winding portion 18 of the carcass ply 16 is along the cord 21 of the reinforcing member 20, and after the turn-up, the winding portion 18 of the carcass ply 16 The cord 17 and the cord 17 of the main body portion 13 of the carcass ply 16 have substantially the same angle with respect to the tangential direction of the bead core 12. As a result, the rigidity in the vicinity of the winding portion 18 of the carcass ply 16 is compared with the case where there is a large angle between the cord 17 of the winding portion 18 of the carcass ply 16 and the cord 17 in the main body portion 13 of the carcass ply 16. And the longitudinal rigidity and lateral rigidity of the completed pneumatic tire 1 are increased.

  Moreover, the upper end 22 of the reinforcing member 20 is located on the outer side in the tire radial direction from the upper end 15 of the bead filler 14. Therefore, at the time of turn-up, the winding portion 18 of the carcass ply 16 is wound up to the end along the cord 21 of the reinforcing member 20 and the cord 17 of the main body portion 13 of the carcass ply 16 without contacting the bead filler 14 without the cord. It is done. Therefore, the cord 17 of the winding portion 18 of the carcass ply 16 and the cord 17 of the main body portion 13 of the carcass ply 16 have substantially the same angle with respect to the tangential direction of the bead core 12.

  In addition, since the upper end 22 of the reinforcing member 20 is on the inner side in the tire radial direction from the tire maximum width position 2, the length of the reinforcing member 20 is suppressed to a necessary minimum, and the mass of the pneumatic tire 1 is excessive. In addition, the manufacturing cost can be reduced.

  Further, in the pneumatic tire 1 in which the winding end 19 of the carcass ply 16 is on the outer side in the tire radial direction from the tire maximum width position 2, when there is no reinforcing material 20, the cord 17 of the winding portion 18 of the carcass ply 16 and the carcass ply 16 The cord 17 of the main body portion 13 is easily displaced greatly. Therefore, the effect of providing the reinforcing material 20 in such a pneumatic tire 1 is great.

  Further, if the relationship between the number of ends HE of the cord 21 of the reinforcing member 20 and the number of ends PE of the cord 17 of the winding portion 18 of the carcass ply 16 is 0.7PE ≦ HE ≦ 1.0PE, Since the number of the cords 21 and the number of the cords 17 of the winding part 18 are close to 1: 1, the cords 17 of the winding part 18 are likely to follow the cords 21 of the reinforcing member 20. Therefore, the cord 17 of the winding portion 18 and the cord 17 of the main body portion 13 of the carcass ply 16 are likely to have the same angle with respect to the tangential direction of the bead core 12.

  Further, if the lower end 23 of the reinforcing material 20 is located at the position of the upper end 11 of the bead core 12, the winding portion 18 of the carcass ply 16 contacts the reinforcing material 20 without contacting the bead filler 14 without the cord. Therefore, at the time of turn-up, the cord 17 of the winding portion 18 of the carcass ply 16 follows the cord 21 of the reinforcing member 20 from the vicinity of the root, and the cord 17 of the winding portion 18 and the cord of the main body portion 13 of the carcass ply 16 17 tends to be at the same angle with respect to the tangential direction of the bead core 12. Further, since the reinforcing member 20 is not longer than necessary on the inner side in the tire radial direction, the mass of the pneumatic tire 1 is not excessive, and the manufacturing cost can be suppressed.

  In order to confirm the effect of the said embodiment, the pneumatic tire of the comparative example of Table 1 and an Example was evaluated. The size of the pneumatic tire to be evaluated was 195 / 65R15 91S. In addition, the cord in the side part of the main body part of the carcass ply is assumed to extend in the tire radial direction. Therefore, the angle of the cord at the side portion of the main portion of the carcass ply with respect to the tire circumferential direction (coincident with the tangential direction of the bead core) was 90 °.

  Table 1 shows the presence or absence of a reinforcing material (corresponding to the reinforcing material 20 in the above embodiment) and the position of the end of the reinforcing material in the pneumatic tire to be evaluated. Note that the cord of the reinforcing material extends in the tire radial direction. Therefore, the angle of the reinforcing member cord with respect to the tire circumferential direction was 90 °. In Table 1, the upper end is an end portion on the outer side in the tire radial direction, and the lower end is an end portion on the inner side in the tire radial direction. Further, as shown in Table 1, the distance from the upper end of the bead core to the upper end of the reinforcing member (distance in the tire radial direction) is 5/6 of the distance from the upper end of the bead core to the maximum tire width position (distance in the tire radial direction). there were.

  The evaluation items were the cord angle, longitudinal rigidity and lateral rigidity of the carcass ply winding portion. The evaluation method is as follows.

<Cord angle of the carcass ply winding part>
The angle of the cord of the carcass ply winding portion in the manufactured pneumatic tire with respect to the tire circumferential direction was measured.

<Vertical rigidity>
A 50t stiffness tester was used for the evaluation. The pneumatic tire was assembled to a regular rim (rim size: 15 × 6.5 J), and the internal pressure was set to 220 kPa. In the state where the camber angle was 0 °, the vertical stiffness was obtained by dividing the amount of change in the vertical force between the longitudinal loads of 4.2 kN ± 490 N by the amount of change in the vertical deflection in the vertical direction. The obtained value was converted into an index with the comparative example as 100. The larger the index, the better the longitudinal rigidity.

<Lateral stiffness>
A 50t stiffness tester was used for the evaluation. The pneumatic tire was assembled to a regular rim (rim size: 15 × 6.5 J), and the internal pressure was set to 230 kPa. In a state where a longitudinal load of 4.2 kN was applied, a lateral deflection amount was measured by applying a load of 30% of the longitudinal load as a lateral force, and the lateral stiffness was obtained by dividing the lateral force by the lateral deflection amount. The obtained value was converted into an index with the comparative example as 100. The larger the index, the better the lateral rigidity.

  The results are shown in Table 1. In the comparative example, the cord angle of the carcass ply winding portion was 80 ° and did not match the cord angle of the main portion of the carcass ply. The angle was 90 °, which coincided with the cord angle of the main part of the carcass ply. In addition, the pneumatic tires of the examples were superior in longitudinal rigidity and lateral rigidity than the pneumatic tires of the comparative examples.

DESCRIPTION OF SYMBOLS 1 ... Pneumatic tire, 2 ... Tire maximum width position, 10 ... Bead part, 11 ... Upper end of bead core, 12 ... Bead core, 13 ... Main part of carcass ply, 14 ... Bead filler, 15 ... Upper end of bead filler, 16 ... Carcass ply, 17 ... cord of carcass ply, 18 ... winding portion, 19 ... winding end of carcass ply, 20 ... reinforcing material, 21 ... cord of reinforcing material, 22 ... upper end of reinforcing material, 23 ... lower end of reinforcing material, 30 ... belt, 31 ... belt reinforcing layer, 32 ... tread portion, 33 ... sidewall, 34 ... inner liner, 35 ... rubber chafer, 40 ... band body, 41 ... green case, 43 ... tread body, 44 ... raw tire, 110 ... Bead part, 113 ... Body part, 116 ... Carcass ply, 117 ... Cord, 118 ... Winding up part

Claims (3)

Provided on both sides of the tire width direction with a bead portion composed of a bead core and a bead filler provided on the outer side in the tire radial direction of the bead core,
A carcass ply in which a plurality of cords extending in the radial direction are covered with rubber is folded around the two bead portions from the inside to the outside in the tire width direction and wound up, whereby the carcass between the two bead portions is wound. A main body portion of the ply and a winding portion of the carcass ply on both sides in the tire width direction of the main body portion are formed;
In the pneumatic tire where the winding end of the winding portion is on the outer side in the tire radial direction from the tire maximum width position, and the tire maximum width position is on the outer side in the tire radial direction from the end portion on the tire radial direction of the bead filler,
Between the bead filler and the rolled-up portion, a reinforcing material in which a plurality of cords are covered with rubber is provided,
The tire radial direction outer end of the reinforcing material is between the tire radial direction outer end of the bead filler and the tire maximum width position,
The pneumatic tire, wherein the cord of the reinforcing member and the cord of the main body portion are arranged at the same angle with respect to a tangential direction of the bead core. The relationship between the number of ends HE of the cord of the reinforcing material and the number of ends PE of the cord of the winding portion of the carcass ply is as follows:
0.7PE ≦ HE ≦ 1.0PE
The pneumatic tire according to claim 1, wherein   3. The pneumatic tire according to claim 1, wherein an end portion of the reinforcing member on an inner side in a tire radial direction is located at an end portion of the bead core on an outer side in the tire radial direction.

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