CN103204036B - Air-inflation tyre - Google Patents

Abstract

The present invention provides a pneumatic tire capable of suppressing detachment of a carcass ply from a bead core during vulcanization molding, suppressing an increase in tire weight, and improving sports performance and durability. The pneumatic tire of the present invention has a bead core (11), a bead filler (12) disposed outside the bead core (11) in the tire radial direction, and a tire axially outer side passing through the bead core (12) and wound around the bead core (11). The bead core (11) is the carcass ply (4) rolled from the outside to the inside; the bead filler (12) is composed of the first bead filler (121) and the second bead filler (122); the carcass ply The layer (4) consists of a main body (41) extending from the tire equator towards the bead core (11) and rolled up on the bead core (11) and along the first bead filler (121) and the second bead filler ( 122) constituted by a rolled-up portion (42); the rolled-up end (42E) is located between the first bead filler (121) and the second bead filler (122).

Description

pneumatic tire

technical field

The present invention relates to a pneumatic tire including a bead core, a bead filler, and a carcass ply; the bead core is buried in a bead portion; and the bead filler is disposed on the bead core Outside in the radial direction of the tire: the carcass ply passes through the axially outer side of the bead core, and is rolled up around the bead core from the outside to the inside.

Background technique

Conventionally, with regard to pneumatic tires, attempts have been made to increase the rigidity of the tires in order to improve driving performance and other sports performance. Specifically, the height or width of the bead filler is increased, or a reinforcing layer is provided on the sidewall portion to increase the rigidity of the tire. However, these methods have problems such as deterioration of fuel consumption of the vehicle due to an increase in tire weight, or degradation of riding comfort due to increase in longitudinal stiffness of the tire.

Therefore, the following patent document 1 discloses a pneumatic tire whose purpose is to increase the lateral rigidity of the tire while reducing the weight of the tire, thereby improving the driving stability. The outer surface extends from the axially outer side to the inner side in the tire radial direction of the bead core. According to this pneumatic tire, since the carcass ply is provided on the outer side of the bead portion, that is, the position where tension acts when the tire is deformed, the lateral rigidity of the tire can be increased, and thus the driving stability can be improved.

However, in the pneumatic tire of Patent Document 1, the end portion of the carcass ply extends and is locked on the inner side of the tire axial direction along the bead core on the inside of the bead core in the tire radial direction. When internal pressure and tension act on the ply cord, the locking force is weak, so the carcass ply may be detached from the bead core.

In addition, Patent Document 2 below discloses a pneumatic tire in which a carcass ply has a ply body portion and a ply turn-back portion; edge; the ply turn-back portion is connected to the main body of the ply, and is provided around the bead core bottom surface and the axially outer and inner sides of the bead core by connecting the bead core surrounding portion to surround the tire The bead core and the bead filler are locked on the bead portion, and the bead core surrounding portion hangs down from the outer edge to the tire axially outer side of the bead core and passes through the tire circumferentially inner peripheral surface of the bead core , erected on the inner side of the bead core in the tire axial direction.

According to the pneumatic tire of Patent Document 2, since the carcass ply is firmly locked to the bead portion, detachment of the carcass ply during vulcanization molding can be suppressed. However, the end portion of the carcass ply, that is, the end portion of the ply turnback portion, is located at the center portion in the tire radial direction on the inner side of the bead filler, resulting in a difference in height and easily causing cracks due to stress concentration.

In addition, the pneumatic tire of the following Patent Document 3 has a radially inner bead filler and a radially outer bead filler on the outer side of the bead core in the tire radial direction, and after the carcass ply is wound around the bead core from the inner side to the outer side, Its turned-up end is sandwiched between a radially inner bead filler and a radially outer bead filler. With this structure, the locking force of the carcass ply can be increased, and the detachment of the carcass ply during vulcanization molding can be suppressed. At the same time, it is possible to prevent the separation of the turned-up end of the carcass ply and improve the durability around the bead portion. .

However, the pneumatic tire of Patent Document 3 has a structure in which the carcass ply is wound around the bead core from the inside to the outside, so there is no carcass ply on the outside of the bead portion, and the tire cannot be sufficiently improved. the lateral stiffness. In addition, the weight increases due to the radially outer bead filler, which may adversely affect the sports performance.

prior art literature

patent documents

Patent Document 1: Japanese Patent Application Laid-Open No. 4-260804

Patent Document 2: Japanese Patent Laid-Open No. 2004-130860

Patent Document 3: Japanese Patent Application Laid-Open No. 10-309911

Contents of the invention

The technical problem to be solved in the present invention

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 capable of suppressing the separation of the carcass ply from the bead core during vulcanization molding, suppressing an increase in tire weight, and improving the sports performance and durability sex.

Technical means to solve technical problems

The above objects can be achieved by the present invention described below. That is, the pneumatic tire of the present invention has a bead core, a bead filler, and a carcass ply; the bead core is embedded in the bead portion; and the bead filler is arranged on the bead core. The radially outer side; the carcass ply passes through the tire axially outer side of the bead filler, and is rolled up from the outer side to the inner side around the bead core; the bead filler is composed of the first bead filler and the second bead filler The first bead filler is arranged adjacent to the bead filler, the second bead filler is arranged outside the first bead filler in the tire radial direction; the carcass ply Consisting of a main body portion extending from the tire equator toward the bead core, and a turn-up portion rolled up on the bead core and along the first bead filler and the extending between the second bead filler; the turn-up end of the turn-up portion is located between the first bead filler and the second bead filler, or is located between the second bead filler and the between the main body.

In the pneumatic tire of the present invention, the carcass ply passes through the axially outer side of the bead core, and is rolled up from the outside to the inside around the bead core. Since the carcass ply can properly bear the tension when the tire is deformed, It can increase the lateral stiffness of the tire to improve the sports performance. In addition, since the structure of the carcass ply is such that the turn-up portion rolled up around the bead core is sandwiched between the first bead filler and the second bead filler, the locking force is increased, and it is possible to suppress the risk of the bead filler during vulcanization molding. The carcass ply separates from the bead core. In addition, since the turned-up end of the carcass ply is located between the first bead filler and the second bead filler or between the second bead filler and the main body portion, since it is covered by the second bead filler, it is difficult to generate a height. Poor, suppresses cracks at the rolled-up end and improves durability. In addition, in the present invention, since the bead filler is composed of the first bead filler and the second bead filler, it is not necessary to sandwich the turn-up portion of the carcass ply with other members than the bead filler, and it is possible to prevent the tire from being rolled up. weight gain.

In the pneumatic tire of the present invention, the rubber hardness of the second bead filler is preferably equal to or less than the rubber hardness of the first bead filler. By lowering the rubber hardness of the second bead filler, when the rolled portion of the carcass ply is sandwiched between the first bead filler, the second bead filler can be easily crimped, so that the carcass ply can be effectively improved. of locking force.

In the pneumatic tire of the present invention, the second bead filler preferably has a protrusion extending in the tire circumferential direction formed on a surface of the second bead filler that faces the first bead filler. According to this structure, since the first bead filler and the second bead filler are pressed outward in the tire axial direction during vulcanization molding, the turned-up portion of the carcass ply is pressed by the protrusion of the second bead filler, and further Increased locking force.

In the pneumatic tire of the present invention, the second bead filler is preferably formed alternately in the tire circumferential direction with concave and convex lines extending in the tire radial direction on its surface opposite to the first bead filler, The grooves are formed at positions corresponding to the ply cords of the turn-up portion of the carcass ply. With this structure, the bonding property between the second bead filler and the carcass ply is improved, and thus the locking force of the carcass ply can be further increased.

In the present invention, the concave and convex lines preferably extend in a direction inclined with respect to the radial direction of the tire. Generally, the ply cords of the turn-up portion of the carcass ply are arranged in a direction oblique to the radial direction of the tire, so by forming concave and convex lines extending in a direction oblique to the radial direction of the tire, it is possible to The bondability between the second bead filler and the carcass ply is improved.

Description of drawings

Fig. 1 is a tire meridian half sectional view showing an example of a pneumatic tire of the present invention.

Fig. 2 is an enlarged view showing a main part of the pneumatic tire of the present invention.

FIG. 3 is a cross-sectional view of the second bead filler 122 .

Fig. 4 is a perspective view showing part of a second bead filler.

Fig. 5 is an explanatory diagram schematically showing a partial molding process of a pneumatic tire.

Fig. 6 is a sectional view showing a main part of a pneumatic tire in another embodiment of the present invention.

7 is a cross-sectional view of a bead core and a bead filler in another embodiment of the present invention.

8 is a perspective view and a cross-sectional view of a second bead filler in another embodiment of the present invention.

FIG. 9 is a cross-sectional view showing main parts of pneumatic tires in Comparative Examples 1 and 2. FIG.

Explanation of reference signs

1. Bead portion; 2. Sidewall portion; 3. Tread portion; 4. Carcass ply; 4a. Ply cord; 11. Bead core; 12. Bead core; 41. Main body; 42E. Turn-up end; 42. Turn-up portion; 121. First bead filler; 121a. Surface; 122. Second bead filler; 122a. Surface; 123. Protrusion;

detailed description

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Fig. 1 is a tire meridian half sectional view showing an example of a pneumatic tire of the present invention. Fig. 2 is an enlarged view showing a main part of the pneumatic tire of Fig. 1 .

This pneumatic tire T includes a pair of bead portions 1, a sidewall portion 2 extending radially outward from the bead portion 1, and a tread connected to the radially outer end of the sidewall portion 2 to form a tread. Tread 3. The bead portion 1 is embedded with a ring-shaped bead core 11 formed of a converging body of bead wires wound with a covering rubber, and a tire is disposed outside the bead core 11 in the tire radial direction. Side core 12.

The carcass ply 4 extends between the bead cores 11 arranged in the pair of bead portions 1 , passes the axially outer side of the bead filler 12 , and is rolled up around the bead cores 11 from the outside to the inside. The carcass ply 4 is formed by covering carcass cords arranged in a direction substantially perpendicular to the tire circumferential direction with a topping rubber. As the ply cord, a steel cord or an organic fiber cord is suitably used.

Inside the carcass ply 4 , an inner liner rubber 5 constituting the inner peripheral surface of the pneumatic tire T is provided. The inner cushion rubber 5 has a function of preventing permeation of gas filled in the tire. In addition, in the sidewall portion 2 , the sidewall rubber 6 constituting the outer wall surface of the pneumatic tire T is provided on the outer side of the carcass ply 4 . In addition, a pad rubber may be provided on the inner side in the tire radial direction of the sidewall rubber 6 at least at a portion that contacts the rim flange.

The bead filler 12 extends from the radially outer end of the bead core 11 toward the outer side in the tire radial direction in a tapered shape. The bead filler 12 of the present invention is composed of a first bead filler 121 arranged adjacent to the bead filler 11 , and a second bead filler 122 arranged outside the first bead filler 121 in the tire radial direction. The first bead filler 121 and the second bead filler 122 each have a substantially triangular cross-section. In this embodiment, the surface 121a of the first bead filler 121 opposite to the second bead filler 122 and the surface 122a of the second bead filler 122 opposite to the first bead filler 121 are respectively planes, which are defined from The tire radially outer end and the tire axially inner end of the bead core 11 are formed toward the tire radially outer side and the tire axially outer side.

Preferably, on the surface 122 a of the second bead filler 122 facing the first bead filler 121 , a protrusion 123 extending in the tire circumferential direction is formed. FIG. 3 is a cross-sectional view of the second bead filler 122 . FIG. 4 is a perspective view showing part of the second bead filler 122 , which is a view of the surface 122 a viewed from the first bead filler 121 . The cross-section of the projection 123 is triangular in shape with the front end facing the first bead filler 121 . Preferably, the height of the protrusion 123 from the surface 122 a is 10 to 30% of the maximum thickness H of the second bead filler 122 . If the height h of the protrusion 123 is made less than 10% of the maximum thickness H of the second bead filler 122, it is difficult to obtain the effect of increasing the locking force by the protrusion 123; Difference.

The rubber hardness of the second bead filler 122 is preferably less than or equal to the rubber hardness of the first bead filler 121 . Specifically, the rubber hardness of the first bead filler 121 is preferably 80-100°, and the rubber hardness of the second bead filler 122 is preferably 60-80°. The rubber hardness of the present invention is JIS-A hardness.

The modulus of the first bead filler 121 is preferably larger than that of the second bead filler 122 . If the modulus of the second bead filler 122 is larger than the modulus of the first bead filler 121, it may result in poor stiffness balance, poor ride comfort and driving stability. Specifically, the modulus of the first bead filler 121 is preferably 5.0-15.0 MPa, and the modulus of the second bead filler 122 is preferably 1.0-12.0 MPa. The modulus in the present invention refers to the tensile stress at the time of 100% stretching using a tensile testing machine based on JIS K6251. Here, the test piece used for the test was Dumbbell No. 3, and the measurement was performed under the condition of an ambient temperature of 23°C.

The carcass ply 4 is composed of a main body portion 41 and a turn-up portion 42. The main body portion 41 extends from the tire equatorial plane C toward the bead core 11; the turn-up portion 42 is rolled up on the bead core 11, And extend along the first bead filler 121 and the second bead filler 122 . According to this, the turned-up portion 42 of the carcass ply 4 is sandwiched between the first bead filler 121 and the second bead filler 122, so that the locking force is increased, and the carcass ply 4 can be suppressed from forming during vulcanization molding. The layer 4 is detached from the bead core 11 .

The main body portion 41 passes through the axially outer side surfaces of the second bead filler 122 and the first bead filler 121 , and reaches the axially outer side of the bead filler 11 . The turnup portion 42 is arranged on the inside of the bead core 11 and the first bead filler 121 in the tire axial direction. By arranging the main body portion 41 of the carcass ply 4 on the tire axially outer side surfaces of the bead filler 12 , that is, the first bead filler 121 and the second bead filler 122 , the carcass ply 4 can properly bear the burden of the tire. Tension at the time of deformation, so the lateral rigidity of the pneumatic tire T can be increased, and the sports performance can be improved.

The rolled end 42E of the rolled portion 42 is located between the first bead filler 121 and the second bead filler 122 , or between the second bead filler 122 and the main body portion 41 . In this embodiment, it is assumed that the rolled-up end 42E is located between the surface 121 a of the first bead filler 121 and the surface 122 a of the second bead filler 122 . In this way, since the turned-up end 42E of the carcass ply 4 is covered by the second bead filler 122 , a height difference in the turned-up end 42E is less likely to occur, and the occurrence of cracks in the turned-up end 42E can be suppressed, thereby improving durability.

The pneumatic tire of the present invention is the same as a conventional pneumatic tire except that the bead filler 12 and the carcass ply 4 have the above-mentioned structure, and any conventionally known materials, shapes, structures, manufacturing methods, etc. can be used in the present invention. .

FIG. 5 is an explanatory diagram schematically showing a partial molding process of the pneumatic tire T of the present invention. As shown in FIG. 5( a ), the bead core 11 and the first bead filler 121 are fitted around the drum D. As shown in FIG. Next, as shown in FIG. 5( b ), the first bead filler 121 is pressed by the bead pressing roller S. As shown in FIG. Next, as shown in FIG. 5( c ), a carcass ply is arranged. Next, as shown in FIG. 5( d ), the sidewall rubber 6 , the bedding rubber 7 , and the second bead filler 122 are arranged at predetermined positions. Next, as shown in Fig. 5(e), remove it from the drum D, and use the winding tool R to wrap the carcass ply 4, sidewall rubber 6, and gasket rubber on the inner side of the tire radial direction from the bead core 11. 7. The second bead filler 122 is rolled up from the outer side to the inner side in the tire width direction.

(Other implementations)

(1) In the above embodiment, an example was shown in which the turned-up end 42E of the carcass ply 4 is located between the first bead filler 121 and the second bead filler 122 , but as shown in FIG. 6 , the carcass ply 4 The turned-up end 42E of the layer 4 is preferably located between the second bead filler 122 and said main body portion 41 . With this structure, the locking force of the carcass ply 4 can be further increased.

(2) In the above-described embodiment, the protrusion 123 is formed on the surface of the second bead filler 122 facing the first bead filler 121 , and the cross section of the protrusion 123 is formed in a triangular shape with the front end facing the first bead filler 121 , However, the cross-sectional shape of the protrusion 123 is not limited to this. The section of the protrusion 123 can also be rectangular as shown in FIG. 7( a ).

In addition, the protrusion 123 extending along the tire circumferential direction may also be formed on the surface 121 a of the first bead filler 121 facing the second bead filler 122 as shown in FIG. 7( b ). Furthermore, the protrusions 123 extending in the tire circumferential direction may be formed on both the first bead filler 121 and the second bead filler 122 as shown in FIG. 7( c ).

The height h of the protrusion 123 can be changed periodically along the tire circumferential direction. In this case, the amplitude of the height h preferably fluctuates periodically within a range of 30° or less based on the central axis of the tire within the range of 0 to 100% of the protrusion height centered on 50% of the protrusion height.

(3) As shown in FIG. 8 , the second bead filler 122 may alternately form concave strips 124 and convex strips 125 extending in the tire radial direction in the tire circumferential direction on the surface 122 a opposite to the first bead filler 121 . FIG. 8( a ) is a perspective view of the second bead filler 122 viewed from the first bead filler 121 . At this time, the grooves 124 are preferably formed at positions corresponding to the carcass cords 4 a of the carcass ply 4 . FIG. 8( b ) is an A-A sectional view of FIG. 8( a ), and the dotted line indicates the ply line 4 a of the carcass ply 4 . With this structure, since the bonding property between the second bead filler 122 and the carcass ply 4 becomes good, the locking force of the carcass ply 4 can be further increased, and shear strain in the tire circumferential direction can be reduced. In addition, in this embodiment, the concave line 124 and the convex line 125 may also be formed on the first bead filler 121 , and may be formed on both the first bead filler 121 and the second bead filler 122 . The concave and convex lines.

In the example shown in FIG. 8 , the concave lines 124 and the convex lines 125 extend in the tire radial direction, but it is preferable that the concave lines 124 and the convex lines 125 extend in a direction inclined with respect to the tire radial direction. Since the ply cords 4a of the turn-up portion 42 of the carcass ply 4 are arranged in a direction inclined with respect to the tire radial direction, by forming the concave lines 124 and convex lines extending in a direction inclined with respect to the tire radial direction, 125, the bondability between the second bead filler 122 and the carcass ply 4 can be improved. For example, the inclination angles of the concave lines 124 and the convex lines 125 relative to the radial direction of the tire are 0-15°.

Example

Next, examples and the like which specifically show the configuration and effects of the present invention will be described. In addition, regarding the evaluation items in Examples and the like, the following measurements were performed. The tire size for the test is 195/65R15, and it is mounted on a rim having a rim size prescribed by JATMA.

(1) Weight

Taking the existing example as 100, the weight of each example was evaluated by index.

(2) Locking force

It is judged whether the carcass ply is detached from the bead core due to the internal pressure during vulcanization molding. In Table 1, "○" indicates that the carcass ply was not detached, and "×" indicates that the carcass ply was detached.

(3) Driving stability

The test tires are installed on the real vehicle and driven, and the driver's sensory evaluation is used to score the vehicle with a full score of 100. Taking the conventional example as 100, the index evaluation was performed, and the higher the score, the better the driving stability.

(4) Durability

The durability test was performed based on the method specified in JISD4230, and it was judged whether or not cracks occurred at the turn-up end of the carcass ply. In Table 1, "○" indicates that no cracks occurred at the rolled-up end, and "×" indicates that cracks occurred at the rolled-up end.

Existing example

A pneumatic tire was prepared in which the carcass ply was rolled up from the inside to the outside around the bead core. The bead filler has a single structure and is not composed of the first bead filler and the second bead filler. Table 1 shows the results of the above-mentioned evaluation using this pneumatic tire.

Comparative example 1

A pneumatic tire as shown in FIG. 9( a ) was prepared in which the carcass ply 4 extends from the axially outer side to the inner side of the bead core 11 through the axially outer side of the bead filler 12 . Table 1 shows the results of the above-mentioned evaluation using this pneumatic tire.

Comparative example 2

A pneumatic tire as shown in FIG. 9( b ) was prepared in which the carcass ply 4 passed the tire axially inner sides of the first bead filler 121 and the second bead filler 122 , around the bead core 11 from the inside to the outside. Turned up, the turned-up portion 42 of the carcass ply 4 is sandwiched between the first bead filler 121 and the second bead filler 122 . Table 1 shows the results of the above-mentioned evaluation using this pneumatic tire.

Example 1

A pneumatic tire having the structure shown in Fig. 1 and Fig. 2 was prepared. Table 1 shows the results of the above-mentioned evaluation using this pneumatic tire.

Example 2

A pneumatic tire was prepared in which, on the face 122a of the second bead filler 122 of Example 1, the protrusion 123 extending in the tire circumferential direction was formed. Table 1 shows the results of the above-mentioned evaluation using this pneumatic tire.

Table 1

Existing example Comparative example 1 Comparative example 2 Example 1 Example 2 weight 100 95 103 100 100 Locking force ○ x ○ ○ ○ driving stability 100 105 95 105 105 Durability ○ x ○ ○ ○

As shown in Table 1, in the pneumatic tires of Examples 1 and 2, the carcass ply did not separate from the bead core during vulcanization molding, and compared with the conventional example, the increase in tire weight was suppressed and the sportiness was improved. and durability. In Comparative Example 1, the steering stability was improved compared with the conventional example, but the carcass ply was detached from the bead core during vulcanization molding, and cracks occurred at the turn-up end of the carcass ply. In Comparative Example 2, the carcass ply was not detached from the bead core during vulcanization molding, and cracks did not occur at the turn-up end of the carcass ply, but the steering stability was worse than that of the conventional example.

Claims (3)

1. an air-inflation tyre, it has bead core, bead-core and casingply; Described bead core is embedded in bead part; Described bead-core is configured in the tire radial outside of described bead core; Described casingply, through the tire axial lateral surface of described bead-core, is rolled around described bead core outside-in, be it is characterized in that,

Described bead-core is made up of the first bead-core and the second bead-core, and described first bead-core and described bead core adjoin and configure, and described second bead-core is configured in the tire radial outside of described first bead-core;

Described casingply is made up of main part and the portion of rolling, and described main part extends from the tire equatorial plane to described bead core, described in roll portion and roll at described bead core, and to extend along between described first bead-core and described second bead-core;

Described roll portion roll end between described first bead-core and described second bead-core, or between described second bead-core and described main part;

Described second bead-core forms projection on the face that it is relative with described first bead-core.

2. air-inflation tyre as claimed in claim 1, it is characterized in that, the rubber hardness of described second bead-core is less than or equal to the rubber hardness of described first bead-core.

3. air-inflation tyre as claimed in claim 1, is characterized in that, described projection extends along tire circumference.