JPH075814U - Pneumatic tire - Google Patents

Abstract

(57) [Abstract] [Purpose] The present invention relates to a pneumatic tire having a flatness of 55% or less, which does not impair riding comfort and enhances steering stability during cornering. The pneumatic tire 1 of the present invention comprises a crown portion of a toroidal carcass formed by at least one ply of cords arranged substantially in a radial arrangement, and intersects the plane including the tread circumference at a relatively small angle. A belt composed of at least two rubberized layers in a cord arrangement, a belt reinforcing layer composed of at least one rubberized layer of organic fiber cords arranged substantially parallel to the plane, and the belt and the belt reinforcing. With a tread portion reinforced with layers, comprising a side reinforcing layer consisting of a rubberized layer of tensile resistance cords that are arranged substantially orthogonal to the cord of the ply of the toroidal carcass over the entire circumference of the carcass, The width of the side reinforcing layer is set to be in the range of 0.15 to 0.65 times the sectional height of the tire.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a pneumatic tire having a flatness of 55% or less, which does not impair riding comfort and enhances steering stability during cornering.

[0002]

[Prior art]

 High-performance vehicles with higher engine output and improved aerodynamic characteristics of the body, so-called high-performance vehicles, have high maximum speed and excellent acceleration performance, and have higher steering stability during cornering. is necessary. As a pneumatic tire for this high-performance vehicle, a flat tire whose tire cross-section height is lower than that of a normal tire is generally used. In order for this flat tire to obtain excellent steering stability during cornering, it is preferable to increase the lateral rigidity of the tire as much as possible. For this reason, belt reinforcement is often used to increase lateral rigidity.

[0003]

[Problems to be solved by the device]

 However, if the lateral rigidity of the tire is increased by reinforcing the belt, the amount of deformation in the tire radial direction during load rolling of the tire becomes too small, which deteriorates the riding comfort. Riding comfort may be significantly reduced for low flat radial tires.

Therefore, an object of the present invention is to improve the lateral rigidity of the tire without impairing the riding comfort and to complete a pneumatic tire having good steering stability during cornering.

[0005]

[Means for Solving the Problems]

 SUMMARY OF THE INVENTION The present invention provides at least two layers around a crown of a toroidal carcass consisting of at least one ply of cords arranged in a substantially radial arrangement, with a cross cord arrangement having a relatively small angle to a plane including the tread circumference. And a belt reinforcing layer composed of at least one rubberized layer of organic fiber cords arranged substantially parallel to the plane, and the belt and the belt reinforcing layer. In a pneumatic tire having a tread portion and a flatness of 55% or less, a tensile resistance cord which is arranged substantially orthogonal to the cord of the ply of the toroidal carcass over the entire lateral circumference of the carcass. The side reinforcement layer is made of a rubberized layer, and the width of the side reinforcement layer is 0.15 to 0. It is a pneumatic tire characterized by having a range of 65 times.

An example of a typical cross section in the width direction of the pneumatic tire of the present invention is shown in FIG. 1, in which 1 is a pneumatic tire, 2 is a cord of a carcass ply, 3 is a carcass, 4 is a crown portion, and 5 is a A belt, 6 is a belt reinforcing layer, 7 is a tread portion, 8 is a cord of a side reinforcing layer, and 9 is a side reinforcing layer. The pneumatic tire 1 shown in FIG. 1 has a relatively small angle with respect to a plane including a tread circumference around a crown portion 4 of a toroidal carcass 3 which is composed of at least one ply of cords 2 which are substantially radially arranged. A belt 5 composed of at least two rubberized layers arranged in a cross cord arrangement, and a belt reinforcing layer 6 composed of at least one rubberized layer of organic fiber cords arranged substantially parallel to the plane. A belt 5 and a tread portion 7 reinforced with a belt reinforcing layer 6, and a tensile resistance cord 8 which is arranged substantially orthogonal to the cord 2 of the ply of the toroidal carcass 3 over the entire circumference of the carcass 3. It has a side reinforcement layer 9 consisting of a rubberized layer.

The width of the side reinforcing layer 9 is set in the range of 0.15 to 0.65 times the sectional height of the tire. If this width is less than 0.15 times the sectional height of the tire, sufficient reinforcement of the side parts 10 of the carcass and circumferential rigidity cannot be achieved, and if it exceeds 0.65 times, the rigidity increases. This is because the response to steering is too fast and the driver becomes uncomfortable. Further, it is preferable that the side reinforcing layer 9 is provided on both side portions 10 of the carcass 3 and covers the carcass region from the position above the bead to the center position of the sidewall. The number of the side reinforcing layers 9 is preferably 1 to 2 but can be increased or decreased as necessary. As the cord 8 of the side reinforcement layer 9, it is preferable to use a steel cord or an organic fiber cord represented by a nylon cord. Further, as long as this cord 8 array is a plurality of arrays, a plurality of cords may be arranged along concentric circles having different diameters, or one cord may be arranged in a spiral shape, and it can be appropriately selected. is there. As a method of arranging the cord of the side reinforcing layer 9 substantially orthogonal to the cord 2 of the ply, the cord 8 of the side reinforcing layer 9 attached to the molding drum before vulcanization molding is The cord 8 is arranged along the circumference of the tire, and when it is molded into a green case, the cord 8 is stretched in the longitudinal direction, so that the cord 8 is almost covered in the tire circumference. It is preferable that the cords are arranged in a straight shape along the line, and in that case, the amplitude of the corrugated cord before the vulcanization molding is preferably set to be larger as the cord located radially outward. Fig. 2 shows an example of the corrugated cord 8 of the side reinforcing layer 9 when it is applied to the molding drum. Here, the circumferential length is 1, the amplitude is a, and the number of pitches is n. The circumferential length L of the cord of the side reinforcing layer in the product tire can be determined by the formula shown below.

[Equation 1]

The carcass 3 preferably comprises 1 to 2 plies, and the ply cord 2 is preferably a rayon cord. The belt 5 is preferably composed of 1 to 3 rubberized layers. The cords of this rubberized layer are made of steel or Kevlar cord, and the cords are arranged at an angle of 20 to 50 with respect to the tire equatorial plane. It is preferable that the angle is °. The cord of the belt reinforcing layer 6 is preferably a nylon cord, and the belt reinforcing layer 6 is preferably arranged as a cap layer covering the front surface of the belt and a narrow layer layer covering the belt end.

[0009]

[Action]

 The present invention comprises a side reinforcing layer 9 consisting of a rubberized layer of tensile resistant cords 8 arranged in a plurality of arrays substantially orthogonal to the cords 2 of the carcass 3 ply over the entire circumference of the toroidal carcass 3. By setting the width of the side reinforcing layer 9 to be in the range of 0.15 to 0.65 times the sectional height of the tire, the ride comfort as when the conventional belt is rigidly reinforced is provided. Without deteriorating, the circumferential rigidity and the torsional rigidity of the side portion 10 of the carcass of the high-performance vehicle tire can be increased, and as a result, the lateral rigidity of the tire can be improved. Further, by forming the cords 8 of the side reinforcing layer 9 in a plurality of arrays that are substantially orthogonal to the cords 2 of the ply, damage caused by sharp protrusions or blades along the cords 2 of the ply can be prevented. When received, the side reinforcing layer 9 can suppress the expansion of the wound.

[0010]

【Example】

 A specific embodiment of the pneumatic tire according to the present invention will be described with reference to FIG. In Example 1, the tire size was 275 / 40ZR17, and the aforesaid crown portion 4 of the toroidal carcass 3 consisting of one ply of rayon cords 2 arranged at 90 ° to the plane including the tread circumference, A belt 5 composed of two layers of rubberized layers arranged in a crossed cord arrangement at an angle of 20 ° to the plane, and a rubberized layer of nylon cords arranged in parallel at an angle of 0 ° to the plane. A belt reinforcing layer 6 and a tread portion 7 reinforced by the belt 5 and the belt reinforcing layer 6, and arranged in plural at an angle of 90 ° with respect to the cord 2 of the ply of the toroidal carcass over the entire circumference of the carcass 3. It has a side reinforcing layer 9 consisting of a rubberized layer of a tensile resistant cord 8.

The width of the side reinforcing layer 9 is 0.38 times the sectional height (110 mm) of the tire. Further, the side reinforcing layers were provided on both side portions 10 of the carcass, and were arranged so as to cover the side portion 10 of the carcass from the upper position of the bead to the central portion of the sidewall. A steel cord was used for the cord 8 of the side reinforcement layer 9. In the conventional example, a conventional tire having no side reinforcing layer was used.

Tests were conducted on cornering characteristics, riding comfort, and durability during high-speed running. The cornering and riding comfort tests during high-speed running were evaluated on a 10-point scale based on the driver's feeling during actual running. In the durability test, expansion of the wound after wedge driving was measured and compared. Table 1 shows the test results. The numerical values in the table indicate that the cornering characteristics and riding comfort during high speed driving are greater.

[0013]

[Table 1]

From the results of Table 1, the example has the same riding comfort as the conventional example, and is excellent in cornering property and tire durability during high speed running.

[0015]

[Effect of device]

 The present invention comprises a side reinforcing layer 9 consisting of a rubberized layer of tensile resistant cords 8 arranged in a plurality of arrays substantially orthogonal to the cords 2 of the carcass 3 ply over the entire circumference of the toroidal carcass 3. By setting the width of the side reinforcing layer 9 to be in the range of 0.15 to 0.65 times the sectional height of the tire, the ride comfort can be improved as in the case where rigidity is reinforced by the conventional belt. Of the carcass side portion 10 of the high-performance vehicle tire is improved without increasing the circumferential rigidity and the torsional rigidity. As a result, the lateral rigidity of the tire is improved and the steering stability during cornering is improved. Input from the tire rotation axis is transmitted directly and smoothly to the tread without time loss, and input from the road surface is similarly transmitted to the driver with good response. Further, by forming the cords 8 of the side reinforcing layer 9 in a plurality of arrangements that are substantially orthogonal to the cord 2 arrangement of the ply, damages caused by sharp protrusions, blades, etc., especially along the cord 2 of the ply, can be avoided. When received, the side reinforcing layer 9 can suppress the expansion of the wound, so that the durability of the tire is improved.

[Brief description of drawings]

FIG. 1 is a perspective view of a widthwise half cross section of the inventive tire used in Example 1, in which a tread rubber and a sidewall rubber are partially cut off.

FIG. 2 is a diagram showing a part of the side reinforcing layer 9 in which only one cord is shown in order to explain the arrangement shape of the cords of the side reinforcing layer before being molded, which is attached to the molding drum. .

[Explanation of symbols]

 1 Pneumatic tire 2 Ply cord 3 Carcass 4 Crown portion 5 Belt 6 Belt reinforcement layer 7 Tread portion 8 Side reinforcement layer cord 9 Side reinforcement layer 10 Side portion of carcass

Claims (1)

[Scope of utility model registration request] 1. At least two layers around a crown portion of a toroidal carcass consisting of at least one ply of cords arranged in a substantially radial arrangement, forming a cross cord arrangement having a relatively small angle with respect to a plane including a tread circumference. A belt made of a rubberized layer, a belt reinforcing layer made of at least one rubberized layer of organic fiber cords arranged substantially parallel to the plane, and a tread portion reinforced by the belt and the belt reinforcing layer. With a flat rate of 5
In a pneumatic tire of 5% or less, a side reinforcing layer made of a rubberized layer of tensile resistance cords which is arranged substantially orthogonal to the cord of the ply of the toroidal carcass over the entire circumference of the carcass, A pneumatic tire characterized in that the width of the side reinforcing layer is in the range of 0.15 to 0.65 times the sectional height of the tire.