RU2570061C1 - Pneumatic tire bead - Google Patents

Abstract

FIELD: motor car construction.

SUBSTANCE: tire bead carcass comprises additionally the rubber strip applied on the carcass inner ply. Note here that the extra cord end is located at said rubber strip. The carcass first, outer, ply end is applied on the rubber strip beyond the extra cord edge.

EFFECT: decreased resistance to tire rolling, higher efficiency of the tire structure.

3 dwg, 1 tbl

Description

The invention relates to the automotive industry, namely to pneumatic tires of a radial design with a frame made of rubberized textile cord.

The side of the tire of the pneumatic tire is the most difficult and tough part of it. The bead is designed for a stable fit and sealing (in the case of tubeless) of the tire on the rim of the rim. The basis of strength is a looped steel rod, consisting of a wire coated with a layer of rubber, and eliminating the possibility of stretching. Depending on the purpose of the tire and the load, one or two strength rings are used in its side part. The bead consists of layers of a frame cord wrapping the steel ring from the middle of the tire to the outside, and an inner protective layer filling the space between the steel rod and the cord. The steel ring rod gives the board the necessary rigidity and strength, the filling layer - solidity and a smooth transition from the hard ring to the elastic rubber of the sidewall. On the outside of the side is the so-called chafer or heel - a dense fabric or metallized layer that covers the lapel of the cord and protects the bead from abrasion on the rim and damage during installation.

At the side of the tire of a pneumatic tire, there are the ends of a number of parts — a filler cord, carcass layers and side ribbons (see VV Ragulin “Tire Production Technology.” Chemistry, 1970; VL Biderman et al. “Car Tires”; Goskhimizdat , 1963). Each of these ends of the parts is a zone of stress and strain concentration, therefore, the durability of this zone in operation and, accordingly, the tire as a whole, depends on the choice of the relative position of the parts. For multilayer tires, such a bead pattern is often used when some of the layers are wrapped around the ring, and part is superimposed on top, closing the ends of the wrapped layers (the so-called “closed” bead scheme), which can significantly reduce the level of stresses and deformations in the zone of layer inversion and increase durability designs. To reduce stress concentration and strain, the amount of applied rubber on the carcass layers is also increased, however, this leads to a heavier tire and lower its performance. With the advent of high-performance equipment for one-stage (“flat”) tire assembly, the search for a constructive solution for the so-called “open” bead scheme becomes relevant when all layers are wrapped around the ring. This task is most relevant for light truck tires with a typical two-layer construction of a textile cord carcass. In addition, in order to increase the economy of tire structures and the level of tire rolling resistance, there is a tendency to reduce the thickness of the carcass rubber, or to use thin cord materials, which also reduces the carcass thickness. In this case, the zone of the upper part of the filler cord and the end of the first layer of the carcass becomes critical, since the above changes lead to an increase in specific shear deformations. That is, the need for the minimum necessary rubber layer between the reinforcing materials in the zone of inversion of the layers limits the possibility of reducing the amount of rubber in the frame as a whole. Known solutions aimed at ensuring the operability of the airborne zone under high load conditions have two main directions - the use of a filler cord of a complex structure made up of two rubbers with different modules (US patent 4046183, US patent 6543504), or the use of a special design of the airborne zone and the airborne rings (RF patent 2087324, RF patent 2198795, RF patent 2133676). Both of these solutions can only be used in a new product, since they require significant changes in the geometry of the tire and the distribution of materials and, accordingly, new molds for manufacturing. The main disadvantage of the first direction is the need to change the technological equipment for the production of the filler cord and a significant change in the design of the tire as a whole. In addition, in case of modernization of an existing product, a change in the stiffness and, accordingly, the rubber module of the filling cord will lead to a change in the lateral, angular and circumferential stiffnesses of the tire, which affects the stability and controllability of the car. The second direction requires the use of special assembly equipment and the use of a special wheel design, which is unacceptable for mass-produced products for the existing fleet of cars. The sides of these tires are complex components consisting of a number of parts. Each of the ends of the bead parts - the filler cord, carcass layers and side ribbons of the parts is a zone of stress and strain concentration, which reduces the durability of this zone in operation and, accordingly, the tire as a whole.

The technical result, to which the proposed invention is directed, is to increase the durability of the tire bead zone, increase the cost-effectiveness of the structure, reduce the material consumption of tire manufacture without changing the technological equipment and change the output characteristics of the tire, applicable both when creating new tire designs and when upgrading existing ones.

The technical result, the achievement of which is ensured by the implementation of the entire claimed combination of features, also consists in the possibility of reducing the thickness of the frame rubber and / or the use of thin cord materials, which improves the efficiency of the structure and reduces rolling resistance.

The technical result is achieved by the fact that the tire cover of a pneumatic tire of radial construction, comprising a carcass of rubberized textile cord having at least one bead ring on each side of the bead part, according to the proposed invention further comprises a rubber strip superimposed on the inner layer of the carcass, while the end of the filling the cord is located on the rubber strip and the end of the first layer of the tire carcass is superimposed on the rubber strip above the edge of the filling cord. Placing the end of the first (outer) layer of the carcass and the end of the filler cord on soft rubber dampens the transition of stresses arising between the layers of the carcass. This allows you to reduce the level of deformation in the local zone of the ends of the filling cord and the inversion of the first layer and to ensure the necessary performance of the structure. The width and thickness of the strip are determined on the basis of the calculation of the design of the tire on the allowable level of deformation for the rubber used.

The invention is illustrated by drawings, where:

- in FIG. 1 is a schematic diagram of a side zone of a 215 / 60R16C tire with a “closed” side portion diagram;

- in FIG. 2 shows a diagram of an onboard zone of a prototype tire 215 / 60R16C (“open” circuit);

- in FIG. 3 shows a diagram of the side zone of the spikes 215 / 60R16C of the proposed technical solution;

The drawings in FIG. 1-3 contain the following positions:

1 - the first layer of the frame

2 - the second layer of the frame

3 - filling cord

4 - side ring

5 - rubber band

Table 1 shows the results obtained when testing tires 215 / 60R16C with a two-layer frame and a different design of the side zone.

The proposed constructive implementation of the side zone of the pneumatic tire tire allows serial production without changing the existing technology; including the modernization of finished products and to achieve economic benefits, secured by a gain in the mass of the tire without deterioration of its technical indicators.

Claims (1)

The tire bead of a pneumatic tire including a rubber textile cord carcass having one bead ring on each side of the bead part, characterized in that it further comprises a rubber strip superimposed on the inner layer of the carcass, with the end of the filler cord located on the rubber strip and the end of the first - outer a layer of the carcass is superimposed on the rubber strip beyond the edge of the filler cord.

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