JP6129724B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire.

  The pneumatic tire is provided with at least two belt layers in which steel cords are inclinedly arranged with respect to the tire circumferential direction on the outer peripheral side of the carcass layer. For the purpose of improving tire performance, a belt reinforcing layer formed by arranging fiber cords substantially in parallel to the tire circumferential direction may be provided on the outer peripheral side of the belt layer.

  For example, in Patent Document 1, in order to improve high-speed durability without impairing smooth handling characteristics during cornering, the number of fiber cords that form the belt reinforcing layer is set from the shoulder region to the center region. It is disclosed that it is gradually reduced.

  In Patent Document 2, in order to improve the handling performance on a dry road surface, the rigidity of the belt reinforcing layer existing outside the tire equator when the vehicle is mounted is more rigid than the rigidity of the belt reinforcing layer existing inside the tire equator. High setting is disclosed.

  In Patent Literature 3, in order to improve grip characteristics, the belt layer is made discontinuous in one or two places in the width direction, and a belt reinforcing layer is formed with an overlap in the width direction around the discontinuous region of the belt layer. However, it is disclosed that it is wound and configured.

  In Patent Document 4, in order to optimize the ground contact shape, a belt reinforcing layer is provided only in a position corresponding to the main groove and a position covering the end of the belt layer. It is disclosed that the modulus is set high.

JP 2001-322405 A JP 2010-215100 A JP-A-5-131804 JP 2013-095368 A

  In Patent Document 1, the cornering performance is improved by gradually decreasing the rigidity of the belt reinforcing layer from the shoulder region toward the center region. However, at the time of cornering, not only the load in the outer region when the vehicle is mounted increases as a whole in the width direction of the tread rubber portion, the ground pressure in the outer region increases, but also in the region of each land portion when the vehicle is mounted. The ground pressure is higher at the outer part than at the inner part. Conventionally, in consideration of the contact pressure at the time of cornering in each land area, there has been no difference in the rigidity of the belt reinforcement layer in each land area in the width direction. There was room for improvement.

  In view of the above points, an object of the present invention is to provide a pneumatic tire capable of improving cornering performance.

  The pneumatic tire according to the present invention includes a carcass layer, a belt layer disposed on the outer peripheral side of the carcass layer in the tread portion, and a plurality of main tires disposed on the radially outer side of the belt layer and extending in the tire circumferential direction. A tread rubber portion having a plurality of land portions divided by grooves, and a belt reinforcing layer in which fiber cords are disposed along a tire circumferential direction between the belt layer and the tread rubber portion, and the tread rubber. The portion includes shoulder land portions at both ends in the tire width direction. The belt reinforcement layer has a rigidity (Ro) of an outer region existing outside the tire equator when the vehicle is mounted higher than a rigidity (Ri) of an inner region existing inside the tire equator, and Within the region of each land portion sandwiched between the main grooves, the rigidity (Rb) of the outer portion when the vehicle is mounted is higher than the rigidity (Rc) of the inner portion, and the outer shoulder land portion when the vehicle is mounted. Vehicles in a region of each land portion where the rigidity (Ra) is higher than the rigidity (Rd) at the inner shoulder land portion and the rigidity (Ra) at the outer shoulder land portion is sandwiched between the main grooves. When the vehicle is mounted in the region of each land portion that is equal to or higher than the rigidity (Rb) of the outer portion at the time of mounting, and the rigidity (Rd) at the inner shoulder land portion is sandwiched between the main grooves. Equal to the rigidity (Rc) of the inner part of Higher than is formed.

  With the pneumatic tire of the present invention, the rigidity of the belt reinforcing layer was set so that the outer region as a whole contact surface is higher than the inner region, and also set as described above in each land portion. It is possible to effectively increase the rigidity of a portion where a load is applied during tire cornering and the contact pressure is increased, and cornering performance can be improved.

(A) is a principal part expanded sectional view of the pneumatic tire which concerns on 1st Embodiment, (b) is a conceptual diagram which shows the rigidity relationship in each site | part about the belt reinforcement layer. It is a conceptual diagram which shows the relationship of the rigidity in each site | part about the belt reinforcement layer of the pneumatic tire which concerns on 2nd Embodiment. It is a conceptual diagram which shows the relationship of the rigidity in each site | part about the belt reinforcement layer of the pneumatic tire which concerns on 3rd Embodiment.

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

[First Embodiment]
The pneumatic tire of the embodiment shown in FIG. 1 is a pneumatic radial tire for passenger cars. The tire includes a pair of left and right bead portions (not shown), a pair of left and right sidewall portions that extend radially outward from the bead portion, and a tread portion 1 that connects outer peripheral ends of the sidewall portions.

  In the tire, a carcass layer 2 is embedded between a pair of bead portions. The carcass layer 2 reaches the bead portion from the tread portion 1 through the side wall portions on both sides, and both end portions thereof are wound and locked by the bead core. The carcass layer 2 is made of a carcass ply formed by parallelly arranging carcass cords made of organic fiber cords with a predetermined number of driving and covering them with rubber. The carcass layer 2 is configured by disposing at least one carcass ply (one in the illustrated example) so that the carcass cord is substantially perpendicular to the tire circumferential direction.

  A belt layer 3 is disposed on the outer peripheral side of the carcass layer 2 in the tread portion 1 (that is, on the outer side in the tire radial direction). The belt layer 3 is provided so as to overlap the outer periphery of the crown portion of the carcass layer 2, and can usually be composed of at least two belt plies. In this example, the belt layer 3 is composed of two belt plies 30 and 31. Yes. The belt layer 3 is formed by inclining a belt cord such as a steel cord at a predetermined angle with respect to the tire circumferential direction and disposing the belt cord 3 at a predetermined interval in the tire width direction. The belt cords are arranged so as to cross each other.

  A tread rubber portion 4 constituting a contact surface is provided on the outer side of the belt layer 3 in the tire radial direction. A plurality of main grooves 40 extending in the tire circumferential direction are provided on the surface of the tread rubber portion 4, that is, the ground contact surface. In the illustrated example, four main grooves 40 are provided, and the main grooves 40 define a plurality of land portions 41, 42, and 43 in the tread rubber portion 4. Specifically, shoulder land portions 41 and 41 are provided between the main groove 40 and the ground contact end at both ends in the tire width direction. Further, three land portions defined by two adjacent main grooves 40, 40 are provided, and the land portion including the tire equator CL is the center land portion 42, and the land portions provided on both sides thereof. The parts are the mediate land parts 43 and 43. Thus, in this example, five land portions 41, 43, 42, 43, 41 are provided in the tire width direction. The land portion may be a rib extending continuously in the tire circumferential direction, or a block formed by arranging a plurality of blocks in parallel in the tire circumferential direction by a lateral groove provided at a predetermined interval in the tire circumferential direction. It may be a column.

  Between the belt layer 3 and the tread rubber portion 4, there is provided a belt reinforcing layer 5 in which an organic fiber cord is disposed along the tire circumferential direction. The belt reinforcing layer 5 is a cap ply that covers the belt layer 3 with its entire width, and is composed of a fiber cord arranged substantially parallel to the tire circumferential direction and a covering rubber that covers the fiber cord. The belt reinforcing layer 5 can be formed by winding a belt-like member formed by arranging a plurality of organic fiber cords in a row and covering them with rubber on the outer periphery of the belt layer 3.

  The pneumatic tire according to the present embodiment is a tire that is designated on the front and back when mounted on a vehicle. That is, when mounting on the vehicle, a surface to be mounted on the outside (vehicle outside) and a surface to be mounted on the inside (vehicle inside) are designated. In FIG. 1, the right side of the paper is the outside when the vehicle is mounted, and the left side of the paper is the inside when the vehicle is mounted.

  In the present embodiment, the belt reinforcing layer 5 has the rigidity (Ro) of the outer region 50 existing outside the tire equator CL when the vehicle is mounted, and the rigidity (Ri) of the inner region 51 existing inside the tire equator CL. (Ie, Ro> Ri). As described above, in the present embodiment, first, the rigidity of the belt reinforcing layer 5 is set to be higher on the vehicle outer side than on the vehicle inner side as the entire ground contact surface, and the tire structure is asymmetrical. Here, the rigidity (Ro) of the outer region 50 is the rigidity of the outer region as a whole when the belt reinforcing layer 5 is divided into two equal parts in the tire width direction around the tire equator CL. The rigidity (Ri) of the area 51 is the rigidity of the entire area in the inner area when the area is divided into two equal parts.

  Further, as shown in FIG. 1B, the belt reinforcing layer 5 has a rigidity (Rb) of the outer portion 52 when the vehicle is mounted in the region of the land portions 42 and 43 sandwiched between the adjacent main grooves 40. Is set higher than the rigidity (Rc) of the inner portion 53 (Rb> Rc). As described above, in the present embodiment, secondly, the rigidity of the belt reinforcing layer 5 is also varied in the width direction even in the regions of the land portions 42 and 43, so that the ground pressure is high and the side rigidity is increased during cornering. . That is, in this example, in the region corresponding to the center region 42 and the mediate land portion 43, the belt reinforcing layer 5 is divided into two equal parts in the width direction, and the rigidity (Rb) of the outer portion 52 is equal to the rigidity (Rc) of the inner portion 53. ) Is higher than

  In the present embodiment, the belt reinforcing layer 5 is divided so as to have a plurality of portions having different rigidity in the tire width direction. The rigidity of the belt reinforcing layer 5 at the outer shoulder land portion 41-1 when the vehicle is mounted is Ra, and the rigidity of the belt reinforcing layer 5 at the inner shoulder land portion 41-2 when the vehicle is mounted is Rd. Further, in the region of the land portions 42 and 43 sandwiched between the adjacent main grooves 40, the rigidity of the outer belt reinforcing layer portion 52 when the vehicle is mounted is Rb, and the inner belt reinforcing layer portion 53 when the vehicle is mounted. Rc is defined as Rc. At this time, the rigidity of each portion of the belt reinforcing layer 5 is set so as to satisfy the relationship of Ra> Rd, Ra ≧ Rb, and Rd ≧ Rc.

  That is, when comparing the shoulder land portions 41-1 and 41-2 at both ends in the tire width direction, the rigidity of the belt reinforcing layer 5 is higher on the outer side than on the inner side of the vehicle (Ra> Rd). Further, in the center land portion 42 and the mediate land portion 43, the rigidity of the outer belt reinforcing layer portion 52 is set higher than the rigidity of the inner belt reinforcing layer portion 53 in the area of each land portion (Rb> Rc), the rigidity of the outer belt reinforcing layer portion 52 is set to be equal to or lower than the rigidity of the outer shoulder land portion 41-1 (Ra ≧ Rb), and the rigidity of the inner belt reinforcing layer portion 53 is set to the inner side. It is set below the rigidity at the shoulder land portion 41-2 (Rd ≧ Rc).

  Further, the rigidity of the outer belt reinforcing layer portion 52 is set to be higher than the rigidity of the belt reinforcing layer 5 in the inner shoulder land portion 41-1 (Rb> Rd). Further, the rigidity (Rb) of the outer belt reinforcing layer portion 52 is set to be higher than the rigidity (Rc) of the inner belt reinforcing layer portion 53 in the other land portions 42 and 43 as well as in the same land portion. ing.

  The rigidity of the belt reinforcing layer 5 at the position corresponding to the main groove 40 is not particularly limited. However, considering that the rigidity is generally low at the groove bottom, it is preferable that the rigidity of the belt reinforcing layer 5 at the portion 54 corresponding to the groove bottom is high. Therefore, in this embodiment, as shown in FIG.1 (b), in the part 54 corresponded to a groove bottom, it is made to correspond with the rigidity of a high rigidity side among the belt reinforcement layers 5 of the both sides. Specifically, in the main groove region between the outer shoulder land portion 41-1 and the mediate land portion 43, the rigidity (Ra) in the outer shoulder land portion 41-1 is set, and the center land portion 42 and the mediate land portion are 43, the rigidity (Rb) of the outer belt reinforcement layer portion 52 is set in the main groove region between the inner shoulder land portion 41-2 and the mediate land portion 43. The rigidity (Rd) at the portion 41-2 is used.

  In the present embodiment, as specific means for changing the rigidity of the belt reinforcing layer 5 as described above, a difference in tensile strength per unit width (for example, per 1 cm) of the belt reinforcing layer 5 and / or a fiber cord is covered. It is preferable to depend on the hardness difference of the rubber. For example, the thickness and material of the fiber cords constituting the belt reinforcing layer 5 are changed, the number of the fiber cords driven (the number of embedded fiber cords per 25 mm width) is changed, or the number of the belt reinforcing layers 5 stacked ( The tensile strength can be varied by changing the number of windings). The difference in tensile strength at each site is not particularly limited, but a difference of 5% or more is preferable. The tensile strength of the belt reinforcing layer 5 can be obtained, for example, by measuring the tensile strength of the fiber cord with a breaking load in accordance with JIS L1017 and multiplying the breaking load by the number of fiber cords driven.

  Further, for example, the rigidity of the belt reinforcing layer 5 may be changed by changing the blending of the covering rubber constituting the belt reinforcing layer 5 to give a difference in rubber hardness. The hardness difference of the coated rubber is not particularly limited, but is preferably 3 ° or more as measured by a type A durometer in accordance with JIS K6253 (measurement temperature: 23 ° C.).

  According to the present embodiment having the above-described configuration, the rigidity of the belt reinforcing layer 5 is set to be higher on the vehicle outer side than on the vehicle inner side as a whole of the ground contact surface. However, since the rigidity of the belt reinforcing layer 5 is varied in the width direction to increase the rigidity of the portion where the load is applied during cornering, the grip performance during cornering can be effectively improved, and the cornering performance is improved. be able to.

  In particular, in the areas of the land portions 42 and 43, there is a difference in rigidity between the outer portion 52 and the inner portion 53, and the rigidity of the entire land portion is not increased. This can contribute to the improvement of cornering performance.

  Further, since the rigidity of the inner belt reinforcing layer portion 53 in the area of each land portion 42, 43 is set to be equal to or less than the rigidity of the inner shoulder land portion 41-2 (Rd ≧ Rc), The wiping phenomenon due to the force toward the center (in-plane contraction force) can be moderately suppressed. From this point, the ground contact property can be improved and the cornering performance can be improved.

[Second Embodiment]
FIG. 2 is a view showing the rigidity of the belt reinforcing layer 5 of the pneumatic tire according to the second embodiment. In this example, the belt reinforcing layer 5 is such that the rigidity (Rb) of the outer portion 52 when the vehicle is mounted in the region of the land portions 42 and 43 sandwiched between the main grooves 40 is as large as the outer land portion when the vehicle is mounted. Highly formed.

  That is, in this example, in the land portions 42 and 43 excluding the shoulder land portions 41 at both ends in the tire width direction, the rigidity of the belt reinforcing layer 5 increases as it goes from the inner land portion to the outer land portion when the vehicle is mounted. It is comprised so that it may become. Specifically, the rigidity of the outer belt reinforcing layer portion 52 in the area of the land portions 42 and 43 is not constant between adjacent land portions as in the first embodiment. Of the three outer belt reinforcing layer portions 52, the rigidity Rb1 of the belt reinforcing layer portion 52-1 in the portion corresponding to the mediate land portion 43 on the vehicle inner side is the lowest (where Rb1> Rd), and the vehicle outer mediate The rigidity Rb3 of the belt reinforcing layer portion 52-3 corresponding to the land portion 43 is the highest, and the rigidity Rb2 of the belt reinforcing layer portion 52-2 in the portion corresponding to the center land portion 42 is set in the middle (Rb1). <Rb2 <Rb3).

  Thus, according to the second embodiment, the rigidity of the outer belt reinforcement layer portion 52 in each land portion 42, 43 is set to increase from the vehicle inner side toward the outer side for each land portion. More appropriate rigidity distribution can be achieved with respect to the load applied during cornering. Moreover, by suppressing the rigidity difference in the land portions 42 and 43 from becoming excessively large, it is possible to suppress the deterioration of the ground contact shape due to the rigidity difference, and further improve the cornering performance by improving the ground contact performance. Can do. Other configurations and effects of the second embodiment are the same as those of the first embodiment, and a description thereof will be omitted.

[Third Embodiment]
FIG. 3 is a view showing the rigidity of the belt reinforcing layer 5 of the pneumatic tire according to the third embodiment. In this example, the belt reinforcing layer 5 includes not only the rigidity (Rb) of the outer portion 52 when the vehicle is mounted in the region of the land portions 42 and 43 sandwiched between the main grooves 40, but also the rigidity (Rc) of the inner portion 53. ) Is also formed higher in the outer land portion when the vehicle is mounted.

  That is, in this example, with respect to the configuration of the second embodiment, the rigidity of the inner belt reinforcing layer portion 53 in the area of the land portions 42 and 43 is not constant between adjacent land portions, and the vehicle inner side. It is set to become higher toward the outside. Therefore, among the three inner belt reinforcement layer portions 53, the rigidity Rc1 of the belt reinforcement layer portion 53-1 at the portion corresponding to the mediate land portion 43 inside the vehicle is the lowest, and corresponds to the mediate land portion 43 outside the vehicle. The rigidity Rc3 of the belt reinforcing layer portion 53-3 is highest (however, Rc3 ≦ Rd), and the rigidity Rc2 of the belt reinforcing layer portion 53-2 in the portion corresponding to the center land portion 42 is set in the middle thereof. (Rc1 <Rc2 <Rc3).

  Thus, according to the third embodiment, both the rigidity of the outer belt reinforcement layer portion 52 and the rigidity of the inner belt reinforcement layer portion 53 in each of the land portions 42 and 43 are both outside from the vehicle inner side for each land portion. Therefore, it is possible to achieve a more appropriate rigidity distribution with respect to the load applied during cornering. Moreover, by suppressing the rigidity difference in the land portions 42 and 43 from becoming excessively large, it is possible to suppress the deterioration of the ground contact shape due to the rigidity difference, and further improve the cornering performance by improving the ground contact performance. Can do. Other configurations and effects of the third embodiment are the same as those of the second embodiment, and a description thereof will be omitted.

  In the third embodiment, on the premise of the configuration of the second embodiment, the rigidity of the inner belt reinforcing layer portion 53 is changed from the vehicle inner side toward the outer side. However, the configuration of the first embodiment is changed. It may be a premise. That is, the rigidity of the outer belt reinforcing layer portion 52 may be constant between adjacent land portions without changing from the vehicle inner side to the outer side.

  As mentioned above, 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.

  In order to specifically show the configuration and effects of the above embodiment, a radial tire for passenger cars (size: 195 / 60R15) was prototyped and the cornering performance was evaluated. The evaluation method is as follows.

・ Cornering performance: Test tires are mounted on a real vehicle (Japanese 1800cc class four-wheel drive sedan), and three trained test drivers run on the test course (dry road surface and wet road surface), and the handling performance is sensorially evaluated. did. Evaluation was carried out by relative comparison with the tire of Comparative Example 1 as a reference, and the average score of the three persons was displayed as an index with the tire of Comparative Example 1 as 100. The larger the number, the better the cornering performance.

  Example 1 is an example corresponding to the first embodiment, and the belt reinforcing layer 5 is provided with a difference in rigidity by changing the number of fiber cords forming the belt reinforcing layer 5 in the tire width direction. Specifically, in order to obtain the relationship of Ra> Rd, Ra = Rb, Rb> Rc, and Rc <Rd as shown in FIG. 1B, the number of driving in each region is 34/25 mm for the rigidity Ra. The stiffness Rb was 34/25 mm, the stiffness Rc was 18/25 mm, and the stiffness Rd was 26/25 mm.

  Example 2 is an example corresponding to the second embodiment described above. Compared to Example 1, the rigidity (Rb) at the outer portion 52 of the center land portion 42 and the mediate land portion 43 is expressed by the land portion outside the vehicle. It was set to be higher. Specifically, in order to satisfy Ra> Rd, Ra ≧ Rb, Rb> Rc, Rc <Rd, and Rb1 <Rb2 <Rb3 as shown in FIG. 34 / 25mm, 30 / 25mm for Rb1, 32 / 25mm for Rb2, 34 / 25mm for Rb3, 18 / 25mm for Rc R, and 26 for Rd Rd Book / 25 mm.

  Example 3 is an example corresponding to the above-described third embodiment. Compared to Example 2, the rigidity (Rc) at the inner portion 53 of the center land portion 42 and the mediate land portion 43 is expressed by the land portion outside the vehicle. It was set to be higher. Specifically, Ra> Rd, Ra ≧ Rb, Rb> Rc, Rc <Rd, Rb1 <Rb2 <Rb3, and Rc1 <Rc2 <Rc3 as shown in FIG. The number of driving is 34/25 mm for the rigidity Ra, 30/25 mm for the rigidity Rb1, 32/25 mm for the rigidity Rb2, 34/25 mm for the rigidity Rb3, 18/25 mm for the rigidity Rc1, For Rc2, 20 lines / 25 mm, for rigidity Rc3, 24 lines / 25 mm, and for rigidity Rd, 26 lines / 25 mm.

  Comparative Example 1 is an example in which the number of fiber cords constituting the belt reinforcing layer 5 is set so as to gradually increase from the inner end toward the outer end when the vehicle is mounted. 18/25 mm, and the number of driving at the outer end was 34/25 mm. Other tires were produced in the same manner as in Example 1.

  The results are as shown in Table 1. Cornering performance was improved in Example 1 in which a difference in rigidity was provided in each block compared to Comparative Example 1. In the second embodiment, the rigidity Rb in the outer portion 52 of each land portion 42, 43 is changed from the vehicle inner side toward the outer side, so that the ground contact property is deteriorated due to the rigidity difference in the land portions 42, 43. The cornering performance was further improved. In the third embodiment, the rigidity Rc in the inner portion 53 of each land portion 42, 43 is also changed from the vehicle inner side toward the outer side, so that the ground contact property is deteriorated due to the rigidity difference in the land portions 42, 43. Was further suppressed, and the cornering performance could be further improved.

DESCRIPTION OF SYMBOLS 1 ... Tread part, 2 ... Carcass layer, 3 ... Belt layer, 4 ... Tread rubber part,
40 ... main groove, 41 ... shoulder land, 42 ... center land, 43 ... mediate land,
DESCRIPTION OF SYMBOLS 5 ... Belt reinforcement layer, 50 ... Outer area | region, 51 ... Inner area | region, 52 ... Outer part at the time of vehicle installation in the area | region of a land part, 53 ... Inner part at the time of vehicle installation in the area | region of a land part

Claims (4)

A plurality of land portions defined by a carcass layer, a belt layer disposed on an outer periphery side of the carcass layer in the tread portion, and a plurality of main grooves disposed on a radially outer side of the belt layer and extending in a tire circumferential direction. A pneumatic tire comprising: a tread rubber portion, and a belt reinforcing layer in which a fiber cord is disposed along a tire circumferential direction between the belt layer and the tread rubber portion,
The tread rubber part includes a shoulder land part at both ends in the tire width direction,
The belt reinforcing layer is
The rigidity (Ro) of the outer region existing outside the tire equator when the vehicle is mounted is higher than the rigidity (Ri) of the inner region existing inside the tire equator, and
In the region of each land portion sandwiched between the main grooves, the rigidity (Rb) of the outer portion when the vehicle is mounted is higher than the rigidity (Rc) of the inner portion, and
The rigidity (Ra) at the outer shoulder land when the vehicle is mounted is higher than the rigidity (Rd) at the inner shoulder land, and
The rigidity (Ra) at the outer shoulder land portion is equal to or higher than the rigidity (Rb) of the outer portion when the vehicle is mounted in the area of each land portion sandwiched between the main grooves, and
The rigidity (Rd) at the inner shoulder land portion is equal to or higher than the rigidity (Rc) of the inner portion when the vehicle is mounted in the area of each land portion sandwiched between the main grooves,
A pneumatic tire characterized by being formed.   The belt reinforcing layer is characterized in that the rigidity (Rb) of the outer portion when the vehicle is mounted in the region of each land portion sandwiched between the main grooves is formed higher as the outer land portion when the vehicle is mounted. The pneumatic tire according to claim 1.   The belt reinforcing layer is characterized in that the rigidity (Rc) of the inner portion when the vehicle is mounted in the region of each land portion sandwiched between the main grooves is formed higher toward the outer land portion when the vehicle is mounted. The pneumatic tire according to claim 1 or 2.   The rigidity change of the belt reinforcing layer is due to a difference in tensile strength per unit width of the belt reinforcing layer and / or a hardness difference of rubber covering the fiber cord. The pneumatic tire according to item 1.

Images