KR-20260067217-A - TIRE

KR20260067217AKR 20260067217 AKR20260067217 AKR 20260067217AKR-20260067217-A

Abstract

A tire is disclosed. The disclosed tire comprises: a tread in contact with a road surface; a carcass formed on the outer surface of an inner liner; and a steel belt section including a first steel belt layer, a second steel belt layer, and a third steel belt layer sequentially stacked from the carcass toward the tread side; wherein the first steel belt layer comprises a plurality of first steel cords arranged at a first angle with respect to the circumferential direction of the tire, each having a first bending stiffness; the second steel belt layer comprises a plurality of second steel cords arranged in the circumferential direction of the tire, each having a second bending stiffness smaller than the first bending stiffness; and the third steel belt layer comprises a plurality of third steel cords arranged at a second angle with a sign different from the first angle with respect to the circumferential direction of the tire.

Inventors

정관우
고길주
이지완

Assignees

한국타이어앤테크놀로지 주식회사

Dates

Publication Date: 20260512
Application Date: 20241105

Claims (10)

Tread that contacts the road surface; A carcass formed on the outer surface of the inner liner; A steel belt section comprising a first steel belt layer, a second steel belt layer, and a third steel belt layer sequentially stacked from the carcass toward the tread side; and The first steel belt layer comprises a plurality of first steel cords arranged at a first angle with respect to the circumferential direction of the tire, each having a first bending stiffness, and The second steel belt layer comprises a plurality of second steel cords arranged in the circumferential direction of the tire, each having a second bending stiffness smaller than the first bending stiffness. The above third steel belt layer comprises a plurality of third steel cords arranged at a second angle having a sign different from the first angle with respect to the circumferential direction of the tire.
In paragraph 1, A tire in which the absolute value of the first angle is 15° or more and less than 45°.
In paragraph 2, A tire in which the absolute value of the second angle is the same as the absolute value of the first angle.
In paragraph 3, Each of the above plurality of third steel cords is a tire having the above first bending stiffness.
In paragraph 4, The EPI (Ends Per Inch) of the plurality of first steel cords is 8 or more and 10 or less, and The EPI of the plurality of second steel cords above is 10 or more and 15 or less, and A tire in which the EPI of the plurality of third steel cords is 8 or more and 10 or less.
In paragraph 4, A tire in which the ratio of the first bending stiffness to the second bending stiffness is greater than 1.5 and less than 3.0.
In paragraph 6, Each of the above plurality of first steel cords comprises a plurality of first filaments, each having a diameter of 0.25 mm or less, and Each of the above plurality of second steel cords includes a plurality of second filaments, each having a diameter of 0.30 mm or more, and A tire in which each of the plurality of third steel cords comprises a plurality of third filaments, each having a diameter of 0.25 mm or less.
In Paragraph 7, Each of the above plurality of first steel cords is prepared by twisting 15 or more of the above first filaments, and Each of the above plurality of second steel cords is prepared by twisting 12 or fewer of the above second filaments, and Each of the above plurality of third steel cords is a tire formed by twisting 15 or more of the above third filaments.
In paragraph 1, The above first bending stiffness is experimentally calculated by a bending stiffness measuring device for a first sample in which the first steel cord is provided with a certain length, and The above second bending stiffness is a tire in which the above second steel cord is experimentally calculated by the bending stiffness measuring device for a second sample provided with the above certain length.
In paragraph 1, The above first bending stiffness is theoretically calculated by a first theoretical formula proportional to the elastic modulus of the first steel cord and the second moment of area of the first steel cord, and The tire, wherein the second bending stiffness is theoretically calculated by a second theoretical formula proportional to the elastic modulus of the second steel cord and the second moment of area of the second steel cord.

Description

Tire The present invention relates to a tire, and more specifically, to a tire in which the structure of the steel belt portion is improved. The tire is connected to the vehicle through the rim and rotates while in contact with surfaces such as the ground or road when the vehicle is driven. These tires are designed in various ways to suit the characteristics of the vehicle; medium and heavy vehicles, such as buses and trucks that transport many people or heavy loads, primarily use TBR (Truck and Bus Radial Tire) tires capable of withstanding high loads. For example, these TBR tires include multiple belt layers formed by arranging high-rigidity steel cords to ensure durability against high internal pressure and high loads compared to passenger pneumatic tires. As disclosed in Korean Patent Publication No. 10-2013-0015176, such conventional TBR tires include four belt layers formed by arranging steel cords between the tread in contact with the ground and the carcass. More specifically, in a conventional TBR tire, the four belt layers arranged by arranging steel cords include first to fourth belt layers sequentially arranged from the carcass to the tread side. Here, the first belt layer is provided with steel cords arranged at an angle of 45° to 60° with respect to the circumferential direction of the tire, and serves to reduce shear strain between the second belt layer and the carcass and to reduce the tensile force applied to the carcass, thereby improving the safety factor. In addition, the second belt layer and the third belt layer are provided with steel cords arranged at an angle of 15° to 30° and -15° to -30° with respect to the circumferential direction of the tire, respectively, and perform the main role of the belt layer by strongly tightening the carcass in the circumferential direction and increasing the rigidity of the tread, thus corresponding to the main rigidity belt layer among the four belt layers mentioned above. In addition, the fourth belt layer is provided with steel cords arranged at a smaller angle with respect to the circumferential direction of the tire than the third belt layer, and performs the role of protecting the second belt layer and the third belt layer, which correspond to the main rigidity belt layer as described above. Meanwhile, with the recent increase in environmental concern and the strengthening of various regulations, there is a growing demand for lightweighting tires to improve fuel efficiency. In response to this demand, as a measure to lighten tires, a method of omitting at least one of the first to fourth belt layers of a conventional TBR tire configured as described above may be considered. FIG. 1 is a perspective view showing an example of a belt portion included in a tire according to a comparative example of the present invention. FIG. 2 is a cross-sectional view showing an example of a first steel belt layer, a second steel belt layer, and a third steel belt layer included in a steel belt portion included in a tire according to one embodiment. FIG. 3 is a relationship diagram showing the relationship between the first steel cord included in the first steel belt layer of FIG. 2, the second steel cord included in the second steel belt layer of FIG. 2, and the third steel cord included in the third steel belt layer of FIG. 2. FIG. 4 is a cross-sectional view showing an example of a first filament included in the first steel cord of FIG. 3, a second filament included in the second steel cord of FIG. 3, and a third filament included in the third steel cord of FIG. 3. FIG. 5 is a side view showing a belt drum that arranges a steel belt section including the first steel belt layer, the second steel belt layer, and the third steel belt layer of FIG. 2. FIG. 6 is a side view showing a bending stiffness measuring device that calculates the first bending stiffness of the first steel cord of FIG. 3 and the second bending stiffness of the second steel cord of FIG. 3. The following describes the embodiments of the present invention in detail with reference to the accompanying drawings. The following embodiments are presented to sufficiently convey the concept of the present invention to those skilled in the art to which the present invention pertains. The present invention is not limited to the embodiments presented herein and may be embodied in other forms. In order to clarify the present invention, the drawings may omit the illustration of parts unrelated to the description and may slightly exaggerate the size of components to aid understanding. FIG. 1 is a perspective view showing an example of a belt portion included in a tire according to a comparative example of the present invention. Referring to FIG. 1, a tire (1000') according to one comparative example may include a tread (TR), a carcass (CA), and a belt portion (B'). The tread (TR) can come into contact with the road surface. A carcass (CA) can be formed on the outer surface of an inner liner. The inner liner is