JPH06344719A - Pneumatic tire - Google Patents

Abstract

PURPOSE:To reduce the vibration of tires without deteriorating driving stability so as to enhance riding comfort by properly arranging the cords of a belt. CONSTITUTION:A pneumatic tire has a belt 6 comprising at least two rubberized layers 4, 5 of high-elastic-modulus cords 3 arranged in a crisscross pattern at a relatively small angle to a plane including the circumference of the tread 1, on the outer periphery of a toroidal carcass comprising at least one ply disposed substantially perpendicular to the plane. At least one layer of the belt 6 comprises layers 7a, 7b, 8a, 8b divided from one another by the plane, and the angle alpha of the cord arrangement of the layers 7a, 8a on the inside 9 of the vehicle to the plane when the tire is in a vehicle-mounted position is greater than the angle beta of the cord arrangement of the layers 7b, 8b on the outside 10 of the vehicle to the plane.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic tire in which comfortability is improved by reducing tire vibration and noise without reducing steering stability by optimizing belt cord arrangement. Is.

[0002]

2. Description of the Related Art As a pneumatic tire having a good riding comfort by reducing vibration and noise generated on the tire due to contact with a road surface, for example, a belt has a rubberized surface divided by a plane including a circumference of a tread. There are so-called directional pneumatic tires consisting of layers. Here, the directional pneumatic tire means a tire having the same direction index as the traveling direction of the vehicle.

[0003]

However, since the directional pneumatic tire tends to have a lower circumferential rigidity than a pneumatic tire having a normal belt structure having no dividing layer, the driving / pneumatic tire is difficult to drive. Steering stability such as braking tends to deteriorate. Therefore, in order to increase the lowered circumferential rigidity, the cord arrangement angle of the divided cord rubberized layer must be smaller than usual with respect to the plane including the tread circumference, but the cord arrangement angle is made smaller. That is, since a shearing force generated between the cord rubber layers is increased, belt separation is likely to occur. In particular, when a tire is mounted on a vehicle, the load applied to the tire when traveling straight ahead differs depending on the camber angle in the width direction of the tire, that is, it is generally greater inside the vehicle than outside the vehicle. For this reason, belt separation easily occurs inside the vehicle, and it is necessary to increase the cord arrangement angle inside the vehicle in order to suppress the belt separation. On the other hand, during cornering, a load transfer occurs from the inside of the tire to the outside of the vehicle.
It is necessary to increase the rigidity outside the vehicle, that is, to reduce the cord arrangement angle in order to obtain good steering stability. In this way, it is desirable to optimize the rigidity in the width direction of the tire according to the running state, but it is generally possible to adjust the rigidity in the width direction in a normal pneumatic tire that does not have a divided belt structure. difficult.

Therefore, the present invention focuses on an asymmetric pneumatic tire having a belt composed of a plurality of divided layers, which suppresses the propagation of tire vibration and has excellent riding comfort. By optimizing the arrangement and the cord arrangement angle for each divided layer, it is an object to suppress a decrease in circumferential rigidity, which is a drawback of this tire, and to obtain good steering stability.

[0005]

SUMMARY OF THE INVENTION The present invention comprises at least one array which is substantially orthogonal to a plane containing the circumference of the tread.
On a circumference of a toroidal carcass made of plies, there is provided a belt formed by laminating at least two layers of a rubberized layer having a high elastic modulus cord in a crossing arrangement of a relatively small angle with respect to the plane, and at least the belt. In a pneumatic tire having one split layer divided by the plane, the cord arrangement angle forming an acute angle with the plane of the split layer occupying the vehicle inner side in the vehicle mounting posture of the tire is outside the vehicle. The pneumatic tire is characterized in that it is larger than the similar cord arrangement angle of the split layer. In addition, the rubberized layer of the high elastic modulus cord, which is composed of the divided layers, is disposed as an outer layer of the belt laminate, and the belt includes two layers of the rubberized layer which is composed of the divided layers, and the division positions thereof are the rubberized layer mutual layers. The arrangement is shifted in the width direction between the cords, each cord arrangement of the division layer is a plane including the circumference of the tread in the intersection region on the obtuse side by the imaginary line extending the cord of at least one division layer and The tires shall be arranged so as to sandwich one of the meridional sections, and the cord arrangement of the split layers shall be such that the imaginary line extending the cords of at least one of the split layers causes the circumference of the tread at the intersection area on the obtuse angle side. , And the meridional section of the tire is sandwiched between the cords, and each cord arrangement of the dividing layers is a phantom line that extends the cords of at least one dividing layer, and The rubberized layer is disposed on the outer layer of the belt stack so as to sandwich either the plane including the circumference of the tire or the meridional section of the tire, and the tread corresponding to each of the divided layers extends along the circumference. A large number of inclined grooves are arranged at intervals, and the intersecting arrangement with the inclined grooves formed by projecting the cords of each divided layer on the tread is such that one of the above planes is formed in the obtuse angle intersection region. It is more preferable that they are sandwiched.

FIG. 1 shows a tread (upper half) and a main part (lower half) of a typical pneumatic tire according to the present invention.
Is shown from above so that the cord arrangement of the belt can be seen. In the figure, 1 is a tread, 2 is a plane including the circumference of the tread, 3 is a high elastic modulus cord, 4 and 5 are rubberized layers, 6
Is a belt, 7a, 7b, 8a and 8b are split layers, 9 is the inside of the tire housing of the vehicle and 10 is also the outside, where 11 is the belt auxiliary layer, 12 is the meridional section of the tire and 13 is It is an inclined groove of the tread. The pneumatic tire shown in FIG. 1 is compared with the plane 2 on the outer circumference of a toroidal carcass (not shown) consisting of at least one ply of an array substantially orthogonal to the plane 2 including the circumference of the tread 1. Belt 6 which is a lamination of rubberized layers 4 and 5 of two layers of high elastic modulus cord 3 which are arranged in a crossing pattern with a relatively small angle.
And the two rubberized layers 4 and 5 constituting the belt 6 are composed of the divided layers 7a and 7b, 8a and 8b which are separated by the plane 2, respectively. Reference numeral 5 denotes a tire mounting posture of the tire, which is a cord arrangement angle α of the division layers 7a and 8a of the inner side 9 with respect to the plane 2.
Is larger than the code arrangement angle β of the divided layers 7b and 8b on the outer side 10, respectively. Further, in FIG. 1, two belt auxiliary layers 11 made of organic fiber cords arranged substantially parallel to the plane 2 are arranged on the outer periphery of the belt 6, but the belt auxiliary layers 11 have tire rigidity. The belt auxiliary layer 11 may be provided as needed to reinforce the belt 6, and the belt auxiliary layer 11 is formed by winding a narrow sheet having 4 to 10 cords coated with rubber in a spiral shape in the width direction of the belt 6 while closely contacting or superimposing them. It is good to form by turning. The high elastic modulus cord of the rubberized layer is preferably steel cord, Kevlar cord or the like.

It is preferable that the rubberized layer having a high elastic modulus cord, which is composed of the divided layers, be arranged in the outer layer of the belt lamination because the outermost layer arrangement first receives the input from the road surface. In the case where the belt 6 has a structure including two rubberized layers 4 and 5 composed of the divided layers 7a and 7b, 8a and 8b, the divided positions of the rubberized layers 4 and 5 are set to the rubberized layer as shown in FIG. It is preferable that they are arranged in the width direction so as to be offset from each other. Since the rigidity at the divided position is inferior to the position in the width direction of other tires, by shifting the divided position between the rubberized layers, parts having low rigidity are dispersed, and the local rigidity of the tire is reduced. This is to prevent

Each cord arrangement of the division layers 7a and 7b, 8a and 8b is formed by an imaginary line extending the cords of at least one division layer, as shown in FIG.
By disposing either one of the plane 2 including the circumference of the tread 1 and the meridional section 12 of the tire in the side crossing area, the forces generated in the width direction of the tire are canceled out to reduce so-called price tear. Has a great effect,
As shown in FIG. 3, by a virtual line obtained by extending the cord of at least one of the division layers, the plane 2 including the circumference of the tread 1 and the meridional section 12 of the tire in the intersection region on the obtuse angle θ side thereof.
8a has a high circumferential rigidity,
The steering stability is good, and 8b has little distortion at the belt edge and has a great effect on separation, so that the cord arrangement of these can be selected according to the performance required for the tire.

Further, in the relationship between the tread 1 and the belt outer layer, as shown in FIG. 5, each cord arrangement of the divided layers 4 is formed by an imaginary line extending the cords of at least one of the divided layers so that their obtuse angle θ side. The rubberized layer 5 arranged to sandwich either the plane 2 including the circumference of the tread 1 or the meridional section 13 of the tire in the intersection area of the belt is arranged as an outer layer of the belt stack, while the respective divided layers 8a, 8b are arranged. A plurality of inclined grooves 13 are arranged at intervals along the circumference of the tread 1 corresponding to, and the inclined grooves 13 formed by projecting the cords 3 of the respective divided layers 8a and 8b onto the tread 1 (accurately It is preferable that the intersecting arrangement with the center line 14) of the inclined groove 13 is such that either one of the planes 2 and 12 is sandwiched between the intersecting regions on the obtuse angle γ side. The reduced rigidity at the position of the inclined groove 13 is compensated by the cords of the dividing layers 8a and 8b, and the inclined groove 1
Since it is possible to suppress movements such as contraction of No. 3, it is advantageous for steering stability and also advantageous for reducing noise generation.

[0010]

The present invention occurs between the road surface and the tread 1 because at least one layer of the belt 6 is composed of the dividing layers (for example, 7a and 7b) divided by the plane 2 including the circumference of the tread 1. Dividing the vibration into two systems to suppress the vibration propagation, and further, dividing layer 7 constituting each rubberized layer 4, 5.
By making the arrangement angles α and β of a and 8a, 7b and 8b with respect to the above plane larger than the dividing layers 7a and 8a of the inner side 9 and the dividing layers 7b and 8b of the outer side 10, the inner side 9 of the tire during straight running. It suppresses the belt separation that tends to occur on the outside of the tire, and also on the outside of the tire during cornering.
A large circumferential rigidity required at 0 can be obtained.

[0011]

EXAMPLES Specific examples of the pneumatic tire according to the present invention will be described with reference to the drawings. The tire used in Example 1 is the invention tire shown in FIG. 1 and has a tire size of 255 / 40ZR17 and a toroidal carcass consisting of one ply arranged at 90 ° with respect to the plane 2 including the circumference of the tread 1. 26 ° with respect to the plane 2 on the outer circumference of
Has a belt 6 formed by laminating two rubberized layers 4 and 5 of steel cords 3 in an intersecting arrangement, and each of the two rubberized layers 4 and 5 constituting the belt 6 has the plane 2
It is composed of divided layers 7a and 7b, 8a and 8b separated by. Each cord arrangement of the dividing layers 8a and 8b constituting the rubberized layer 5 located on the outer layer of the belt corresponds to each cord 3.
Are arranged so as to sandwich both the plane 2 including the circumference of the tread 1 and the meridional section 12 of the tire in the intersection region on the obtuse angle θ side generated by the imaginary extension line of
The cord arrangement angle α with respect to the plane 2 was 32 °, and the cord arrangement angle β of the divided layer 8b on the outer side 10 was 25 °.
Further, the respective cord arrangements and cord arrangement angles of the divided layers 7a and 7b constituting the rubberized layer 4 located in the belt inner layer are the same as those of the divided layers 8a and 8b constituting the rubberized layer 5 located in the belt outer layer, The division layers 7a and 8a and 7b and 8b, which have a laminated relationship, are arranged so as to intersect each other. The width of the rubberized layers 4, 5 is 230 mm for the outer layer 5 and 2 for the inner layer 4.
The width of the divided layer is 40 mm, and the inner layer 8a of the outer layer 5 is 110 mm.
mm, the outer side 8b is 115 mm, and the inner side 7a of the inner layer 4 is
It was 85 mm and the outer side 7b was 150 mm. Also, belt 6
Two belt auxiliary layers 11 made of organic fiber cords arranged at substantially 0 ° with respect to the plane 2 were arranged on the outer periphery of the above. The belt auxiliary layer 11 was formed by spirally winding a narrow sheet in which ten cords were coated with rubber in the width direction of the belt 6.

In the inventive tire used in Example 2, the cord arrangements of the dividing layers 7a and 7b, 8a and 8b are different from each other in the tread 1 at the intersection region on the obtuse angle θ side thereof caused by the virtual extension line of each cord. It has a belt 6 composed of two layers of rubberized layers 4 and 5 arranged so as to sandwich one of the plane 2 including the circumference and the meridional section 12 of the tire, and corresponds to each of the divided layers 8a and 8b of the outer layer of the belt. The tread 1 is provided with a large number of inclined grooves 13 at intervals along the circumference thereof, and the cords 3 of the respective divided layers 8a and 8b are projected on the tread 1 to form an intersecting arrangement with the inclined grooves 13. However, the arrangement is such that either one of the planes 2 and 12 is sandwiched in the intersection area on the obtuse angle γ side, and both the belt outer layer and the belt inner layer,
Almost the same tire as that used in Example 1 except that the cord arrangement angle α of the inner divided layers 7a and 8a with respect to the plane 2 was 32 ° and the cord arrangement angle β of the outer divided layers 7b and 8b was 25 °. It is the same.

The tire used in the conventional example is composed of two layers of a normal rubberized layer having no dividing layer, and is almost the same as the tire used in Example 1 except that the cord arrangement angle is 25 °. It is the same.

The tests were conducted on riding comfort, steering stability, durability and the like. All of the performances were evaluated by feeling in actual vehicle running. Table 1 shows the test results. The numerical values in the table are shown as an index ratio with the conventional example being 100, and the smaller the numerical value, the better the riding comfort,
The other performance is better as the numerical value is larger.

[0015]

[Table 1]

From the test results, Example 1 and Example 2
Compared with the conventional example, the high-speed durability is the same, and riding comfort, steering stability, belt edge durability and plysteer component are improved. In addition, Example 2 is superior to Example 1 in the plysteer component.

[0017]

According to the present invention, since at least one layer of the belt 6 is composed of the dividing layers (for example, 8a and 8b) which are separated by the plane 2 including the circumference of the tread 1, the tread 1 is separated from the road surface. The generated vibration can be divided into two systems to suppress vibration propagation, and good ride comfort can be obtained. Also,
Dividing layers 7a and 7b, 8a constituting each rubberized layer 4, 5
And 8b with respect to the plane 2 are defined by the inner angles 9 and 9
Divided layers 7a, 8a of the vehicle outer side 10
By making it larger than this, it is possible to suppress belt separation that tends to occur on the inside 9 of the tire during straight running, and to increase the circumferential rigidity required on the outside 10 of the tire during cornering, so durability is improved. It also has the effect of improving steering stability.

[Brief description of drawings]

FIG. 1 is a view of a tread of a typical invention tire used in Example 1 and a main part of a belt as viewed from above, and is cut in a direction in which a cord arrangement of the belt can be particularly seen.

FIG. 2 is a view in which a tread of another invention tire and a main part of a belt are viewed from above and cut in a direction in which a cord arrangement of the belt can be seen.

FIG. 3 is a diagram illustrating a method of determining a code arrangement between division layers 8a and 8b shown in FIG.

FIG. 4 is a diagram illustrating a method of determining a code arrangement between other division layers 8a and 8b.

FIG. 5 is a code arrangement between the other division layers 8a and 8b,
It is a figure explaining the determination method of arrangement | positioning of the code | cord 3 and the inclination groove | channel 13.

[Explanation of symbols]

 1 Tread 2 Plane including tread circumference 3 High modulus cord 4, 5 Dividing layer 6 Belt 7a, 7b Dividing layer 8a, 8b Dividing layer 9 Inside of vehicle tire housing 10 Outside of vehicle tire housing 11 Belt auxiliary layer 12 Meridional section of tire 13 Inclined groove 14 Center line of inclined groove

Claims (6)

[Claims] 1. A toroidal carcass consisting of at least one ply of an array substantially orthogonal to a plane including the circumference of the tread, and at least two layers forming a cross array of a relatively small angle with respect to the plane. In a pneumatic tire having a belt in which a rubberized layer of a high elastic modulus cord is laminated, at least one layer of which is a divided layer divided by the plane, in a vehicle mounting posture of the tire, A pneumatic tire characterized in that a cord arrangement angle of the occupying division layer with respect to the plane is larger than a similar cord arrangement angle of the division layer outside the vehicle. 2. The pneumatic tire according to claim 1, wherein the rubberized layer of the high elastic modulus cord, which is composed of the divided layers, is arranged in an outer layer of the belt laminate. 3. The belt according to claim 1, wherein the belt includes two rubberized layers, each of which is composed of a divided layer, and the division positions thereof are displaced in the width direction between the rubberized layers. Pneumatic tire. 4. A plane including the circumference of the tread at the intersection region on the obtuse side of each cord arrangement of the split layers by an imaginary line extending the cords of at least one of the split layers, and a meridian section of the tire. The pneumatic tire according to claim 1, 2 or 3, wherein the pneumatic tire is arranged so as to sandwich one or the other. 5. Each cord arrangement of the split layers has both a plane including the circumference of the tread and a meridional section of the tire in an intersection region on the obtuse side thereof by an imaginary line extending the cords of at least one of the split layers. The pneumatic tire according to claim 1, 2 or 3, which is sandwiched. 6. A plane including the circumference of the tread at an intersection region on the obtuse side of each cord arrangement of the split layers by an imaginary line extending the cords of at least one of the split layers, and a meridian section of the tire. A rubberized layer sandwiching one of the two is disposed on the outer layer of the belt stack, while a plurality of inclined grooves are disposed on the tread corresponding to each divided layer at intervals along the circumference of the tread. 3. The crossing arrangement with the inclined groove formed by projecting the cord of FIG. 2 on the tread is arranged so as to sandwich one of the planes in the crossing area on the obtuse angle side thereof. The pneumatic tire according to 4 or 5.