KR20160026426A - Pneumatic tire - Google Patents

Abstract

The present invention relates to a pneumatic tire. According to an embodiment of the present invention, the pneumatic tire comprises a tread part, wherein the tread part includes: a base rubber layer made of any one selected from a first rubber composition exhibiting relatively small rolling resistance and a second rubber composition exhibiting relatively excellent braking force; and a plurality of granules made of the other selected from the first rubber composition and the second rubber composition, and inserted into the base rubber layer. The purpose of the present invention is to provide a pneumatic tire having a cap tread capable of securing excellent driving efficiency and excellent braking performance at the same time, without causing a phenomenon that a vehicle tilts to one side.

Description

{PNEUMATIC TIRE}

The present invention relates to pneumatic tires.

Generally, pneumatic tires have a tread which is in direct contact with the road surface, a cap ply which serves as a protective layer for other components inside the tread, a kash that forms the skeleton of the tire, An inner liner disposed inside the carcass to prevent air from leaking from the carcass; and an inner liner connecting the tread and the bead, A side wall for performing a bending motion, and at least one belt installed between the tread portion and the carcass.

Here, the tread portion may include a cap tread and an undertread. The cap tread is located at the outermost side of the tire and is in contact with the road surface. The cap tread protects the belt and carcass from the external impact and the surrounding environment, and transmits the braking force, driving force, and traction force to the road surface. The under-tread is a rubber layer positioned between the cap tread and the belt. The under-tread relaxes the shear stress generated between the cap tread and the belt to suppress heat generation of the tread portion and prevent cutting and cracking.

On the other hand, in the conventional tire, hysteresis loss is generated in accordance with the frequency response corresponding to the rotation speed of the rubber composition constituting the cap tread. Therefore, as the size of the rolling resistance (RR) of the cap tread becomes smaller, . That is, as the rolling resistance is reduced in the tread portion and the running efficiency is improved, the braking performance is lowered.

In order to simultaneously improve the running efficiency and the braking performance in the cap tread, techniques have been proposed in which different types of rubber are vertically stacked or joined together to form a cap tread. However, since different kinds of rubbers have different friction coefficients and degree of wear between them, there is a problem that the vehicle is tilted to one side.

Korean Patent Laid-Open Publication No. 2006-0002274 (published on Jan. 09, 2006)

The embodiments of the present invention are intended to provide a pneumatic tire having a cap tread capable of simultaneously securing excellent driving efficiency and excellent braking performance without causing a phenomenon that a vehicle is tilted to one side.

According to one aspect of the present invention, there is provided a pneumatic tire comprising a tread portion, wherein the tread portion comprises a base rubber layer made of any one of a first rubber composition exhibiting a relatively low rolling resistance and a second rubber composition exhibiting a relatively high braking force, ; And a pneumatic tire comprising another one of the first rubber composition and the second rubber composition and including a plurality of grains to be inserted into the base rubber layer.

In this aspect, the tread portion may include a cap tread made up of the base rubber layer and the plurality of grains, and an under tread attached to an inner surface of the cap tread and stacked with the cap tread.

In this aspect, the plurality of grains can be dispersed substantially evenly in the base rubber layer.

In this aspect, the granules may have a diameter of 0.1 mm or more and 5 mm or less.

In this aspect, the grain may have a diameter of 0.001% or more and 0.5% or less of the size of the pitch of the tread pattern formed on the outer surface of the base rubber layer.

In this aspect, the volume sum of the plurality of grains may be 0.001% or more and 0.5% or less of the sum of the volume of the base rubber layer and the plurality of grains.

In this aspect, an area occupied by the plurality of grains among the contact surfaces of the cap tread and the ground may be 0.001% or more and 0.5% or less of the contact surface between the cap tread and the ground.

In this aspect, the first rubber composition composition is prepared by mixing and mixing granules composed of the first rubber composition and the other one of the second rubber composition in a semi-flowing state in any one of the second rubber composition, Can be inserted into the base rubber layer through injection molding in a cap tread shape.

In this aspect, the grain may have a columnar shape having a predetermined length.

In this aspect, the length of the columnar grains may be substantially the same as the width of the base rubber layer.

In this aspect, the columnar grains may be inserted into the base rubber layer through injection of the other of the first rubber composition and the second rubber composition into a columnar base rubber layer injected in a cap-tread shape have.

The effect of the pneumatic tire according to the present invention will be described as follows.

According to the embodiments of the present invention, not only can the cab tread ensure both excellent driving efficiency and excellent braking performance, but also prevents a phenomenon in which the vehicle tilts to one side, thereby enabling stable running.

1 is a sectional view of a pneumatic tire according to an embodiment of the present invention.
Fig. 2 is an enlarged view of the cross-sectional structure of the tread portion of Fig. 1;

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

In the following description, well-known functions or constructions are not described in detail since they may obscure the subject matter of the present invention.

Hereinafter, a pneumatic tire according to an embodiment of the present invention will be described with reference to Figs. 1 and 2. Fig.

FIG. 1 is a sectional view showing a tire sectional structure of a pneumatic tire according to an embodiment of the present invention, and FIG. 2 is an enlarged view of a sectional structure of the tread portion of FIG.

1 and 2, a pneumatic tire 1 according to an embodiment of the present invention includes a tread portion 10, a cap ply 20, a carcass 30, an apte 50, a bead 40, A sidewall 60, and a belt 70. As shown in Fig.

The cap tray 10 includes a base rubber layer 100 and a plurality of pellets 200 made of a rubber composition different from the base rubber layer 100 and inserted irregularly in the base rubber layer 100, . ≪ / RTI >

According to one embodiment, the tread portion 10 may include a cap tread 11 and an under tread 12 stacked with the cap tread 11. The base rubber layer 100 and a plurality The kernels 200 may form the cap tread 11. Then, the under-tread 12 may be laminated with the base rubber layer 100 of the cap tread 11. [

Alternatively, according to another embodiment, the tread portion 10 may include a base layer 100 and a plurality of pellets 200 inserted therein without including a separate under-tread. In this case, there may be no tread rubber layer laminated separately in the base layer 100, and at least one of the base layer 100 and the plurality of pellets 200 may replace the under tread.

In this figure, an example is shown in which another under tread 12 is further laminated on the base rubber layer 100 according to the former embodiment. In the following description, another under-tread 12 is described on the basis of a structure in which a further under-tread 12 is laminated. However, as described above, a separate under-tread 12 is not necessarily provided.

The base rubber layer 100 may constitute a layer of the cap tread 11 which is laminated with the under tread 12 and may be made of a material different from the under tread 12 and the plurality of the grains 200. [

The plurality of particles 200 may be made of a material different from the under-tread 12 and may have a circular, triangular, square, or other polygonal cross-section. Alternatively, the cross section of the plurality of grains 200 may have an irregular shape. The plurality of grains 200 may be made of granules having different cross-sectional shapes.

More specifically, each of the kernels 200 may have a columnar shape. For example, one grain 200 may have the shape of a cylinder, a triangular column, a square column, or the like.

When each of the particles 200 has a columnar shape, the height of each of the particles 200 (the length of the column) may be substantially the same as the width of the base rubber layer 100. In this case, each of the grains 200 can extend from one side in the width direction of the base rubber layer 100 to the other side. Both longitudinal ends of each of the granules (200) can be exposed at both ends in the width direction of the base rubber layer (100).

The plurality of grains 200 may each have a diameter of 0.1 mm or more and 5 mm or less. Alternatively, the plurality of grains 200 may each have a diameter of 0.001% or more and 0.5% or less of the pitch of the tread pattern formed on the outer surface of the base rubber layer 100, respectively. Here, the plurality of grains 200 may be composed of grains having substantially the same diameter in the above range, or grains having different diameters within the above range.

If the size of each of the grains 200 is smaller than the above-mentioned range, the physical properties of the material constituting the plurality of grains 200 are not sufficiently exhibited. On the other hand, if the size of each of the grains 200 is larger than the above-mentioned range, each of the grains 200 formed of different materials may be separated from the base rubber layer 100.

The total volume of the plurality of particles 200 included in the cap tread 11 may be 0.001% or more and 0.5% or less of the sum of the volumes of the base rubber layer 100 and the plurality of pellets 200.

Further, when the outer surface of the cap tread 11 contacts the ground, the area occupied by the plurality of grains 200 among the contact surfaces of the cap tread 11 and the ground may be 0.001% or more and 0.5% or less of the contact surface. Here, even if the cap tread 11 is worn, the ratio occupied by the area of the plurality of kernels 200 in the contact surface between the cap tread 11 and the ground can be maintained.

When the total volume of the plurality of particles 200 or the ratio of the area in the contact surface with the ground is smaller than the above range, the physical properties of the material constituting the plurality of particles 200 are not sufficiently exhibited. On the other hand, if the total volume of the plurality of particles 200 or the ratio of the area in the contact surface with the ground is out of the above range, the physical properties of the material constituting the base rubber layer 100 may not be sufficiently exhibited.

Meanwhile, as described above, the rubber composition of each of the granules (200) may be different from the rubber composition of the base rubber layer (100). In addition, it may be different from the rubber composition constituting the under-tread 12.

The plurality of grains 200 may be inserted into the base rubber layer 100. For example, as shown in FIGS. 1 and 2, the plurality of grains 200 may be substantially evenly distributed in the base rubber layer 100.

In this embodiment, the base rubber layer 100 consists of a first rubber composition exhibiting a relatively low rolling resistance (RR) and a second rubber composition having a relatively good braking force (wet traction) The kernel 200 may be made of another one. For example, the base rubber layer 100 may be formed of a rubber composition exhibiting a small rolling resistance, and the plurality of grains 200 may be formed of a rubber composition exhibiting excellent braking force. Alternatively, the base rubber layer 100 may be composed of a rubber composition exhibiting excellent braking force, and the plurality of particles 200 may be composed of a rubber composition exhibiting a small rolling resistance.

On the other hand, the first rubber composition and the second rubber composition may be substances showing different rolling resistance and braking force. Here, the first rubber composition may be a material exhibiting a smaller rolling resistance and braking force than the second rubber composition. In addition, the second rubber composition may exhibit a greater rolling resistance than the first rubber composition and exhibit a superior braking force.

The first rubber composition exhibiting small rolling resistance may be a rubber composition comprising, for example, high vinyl butadiene, including silica. Specifically, the first rubber composition may be a material having a 0 DEG C loss tangent value (0 DEG C Tan?) Of a size smaller than the first value. Here, the first value may be a predetermined value.

The second rubber composition exhibiting excellent braking force may be, for example, a rubber composition containing vinyl styrene butadiene. Specifically, the second rubber composition may be a material having a 60 DEG C loss tangent value (60 DEG C tan?) Of a size larger than the second value. Here, the second value may be a predetermined value, and may be greater than the first value.

The under tread 12 is formed on the inner side of the base rubber layer 100 and can be laminated with the base rubber layer 100. [ The outer surface of the under tread 12 and the inner surface of the base rubber layer 100 can be adhered to each other. The under-tread 12 may also be comprised of a different rubber composition than the first and second rubber compositions.

Meanwhile, the plurality of granules (200) may be prepared by granulating the rubber composition into a granule, a semi-granulation step of bringing the granules into a semi-granular flow state, and mixing the semi-granulated granules with a rubber composition constituting the base rubber layer And then inserted into the base rubber layer 100 through a mixing step. When semi-flowing particles are injected into the rubber composition of the base rubber layer 100 and then injected into the shape of a cap tread 11, a cap tread 11 having a plurality of particles 200 of different materials inserted therein can be formed .

As another example, the above-described cap tread 11 may be formed by injecting the rubber composition constituting the base rubber layer 100 in the shape of a cap tread 11 and then spraying small grains made of another rubber composition.

Alternatively, a method of injecting another rubber composition into the base rubber layer 11 injected in the shape of the cap tread 11 in a stick shape may be used.

According to this embodiment, the tread portion of the pneumatic tire can have excellent rolling resistance and excellent braking force at the same time. In particular, the braking force of the tread portion can be improved as compared with the case where the under tread is laminated on the cap tread composed of a single rubber composition layer without a plurality of grains.

Table 1 below shows experimental results comparing the rolling resistance and the braking force of the conventional tire and the pneumatic tire 1 of the present embodiment. A conventional tread portion 10 of a tire is formed by laminating an under tread 12 on a cap tread 11 composed of only a single rubber composition layer without a plurality of grains 200.

In the present experiment, a conventional tire comprising a cap tread made up of a first rubber composition having a small rolling resistance and a plurality of grains made of a second rubber composition having a superior braking force in the base rubber layer made of the first rubber composition, The rolling resistance and braking force of the pneumatic tire 1 including the cap tread inserted with a volume ratio of about 5% with respect to the sum of the rubber composition and the second rubber composition were respectively measured. The rolling resistance of the tire was measured under the conditions of air pressure of 210 kpa and load of 490 kgf under SAE J2452 / ISO 285580. On the other hand, as the braking force, The braking distance from the rotation speed of 100 km / h to the stop of the tire was measured. In Table 1 below, the rolling resistance and the braking force are 100, respectively, and the rotational resistance and the braking force measured in the experiment using the conventional tire are 100. In the experiment using the pneumatic tire 1 of this embodiment, As a ratio thereof.

Conventional tire Pneumatic tire (1) Cloud resistance 100 99.5 Braking force 100 105.1

Referring to Table 1, when using the base rubber layer formed of different materials and the cap tread including a plurality of grains as in the present embodiment, the rolling resistance is reduced by about 0.05% as compared with the conventional tire, and at the same time, It can be seen that it is improved about 5%. That is, when the pneumatic tire of this embodiment is applied, not only excellent driving efficiency but also excellent driving performance can be ensured at the same time.

Although the pneumatic tire according to the embodiment of the present invention has been described above as a specific embodiment, the present invention is not limited thereto, and the present invention is not limited thereto, and should be construed as having the widest range according to the basic idea disclosed in this specification do. Skilled artisans may implement a pattern of features that are not described in a combinatorial and / or permutational manner with the disclosed embodiments, but this is not to depart from the scope of the present invention. It will be apparent to those skilled in the art that various changes and modifications may be readily made without departing from the spirit and scope of the invention as defined by the appended claims.

1: pneumatic tire 10: tread portion
11: cap tread 12: under tread
100: Base rubber layer 200: Grain
20: Cap fly 30: Carcass
40: Bead 50: Apex
60: side wall 70: belt

Claims (11)

A pneumatic tire comprising a tread portion,
The tread portion
A base rubber layer composed of any one of a first rubber composition exhibiting a relatively small rolling resistance and a second rubber composition exhibiting a relatively high braking force; And
Wherein the first rubber composition and the second rubber composition comprise a plurality of grains which are different from each other and are inserted into the base rubber layer. The method according to claim 1,
The tread portion
A cap tread including the base rubber layer and the plurality of grains;
And an under tread attached to an inner surface of the cap tread and laminated with the cap tread. 3. The method according to claim 1 or 2,
Wherein the plurality of grains are distributed substantially evenly in the base rubber layer. 3. The method according to claim 1 or 2,
Said pellets having a diameter of 0.1 mm or more and 5 mm or less. 5. The method of claim 4,
Wherein the grain has a diameter of 0.001% to 0.5% of a size of a pitch of a tread pattern formed on an outer surface of the base rubber layer. 6. The method of claim 5,
Wherein the sum of the volume of the plurality of grains is not less than 0.001% and not more than 0.5% of the sum of the volume of the base rubber layer and the plurality of grains. The method according to claim 6,
Wherein an area occupied by the plurality of grains among the contact surfaces of the cap tread and the ground is not less than 0.001% and not more than 0.5% of a contact surface between the cab tread and the ground. 3. The method according to claim 1 or 2,
Wherein the plurality of grains comprise:
The first rubber composition composition is prepared by mixing and mixing granules composed of the first rubber composition and the second rubber composition in a semi-flowing state in any one of the first rubber composition mil and the second rubber composition, Wherein said base rubber layer is inserted into said base rubber layer through injection. 3. The method according to claim 1 or 2,
The pellet having a predetermined length. 10. The method of claim 9,
And the length of the columnar grains is substantially the same as the width of the base rubber layer. 11. The method of claim 10,
The pillar-shaped grains may be,
And the other of the first rubber composition and the second rubber composition is inserted into a base rubber layer injected in a cap-tread shape into the base rubber layer.

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