RU2681789C1 - Pneumatic tire - Google Patents

Abstract

FIELD: transportation.SUBSTANCE: invention relates to wheeled vehicles of mainly special purpose. Tire comprises beads, bead rings, side pieces, tread, breaker made up of several layers of rubberized textile or metal cord, carcass with layers of rubberized cord with meridian direction of threads therein. Part of carcass layers is made half-layers, one edge of which is fixed on / at side rings, and the other one is located in the tread zone. Free edges of adjacent half-layers are not joined and inclination of cord threads in semi-layers is made in one side from meridian (meridian section) of tire at angle of 10–75 degrees.EFFECT: improved operational properties of tire by increasing traction-grip properties at change of internal pressure in tire.1 cl, 2 dwg

Description

The invention relates to pneumatic tires of wheeled vehicles with a directional tread pattern of high cross-country ability and adjustable internal pressure.

The purpose of the invention is to improve the performance of the tire by increasing their traction and coupling properties, reducing internal losses in the driving mode, stresses in the cover rubber of the sidewalls while reducing the internal pressure in the tires, increasing the service life of the tire.

Tires with a directional tread pattern of high cross-country ability with adjustable pressure, as a rule, are used in special machines: military automotive equipment, agricultural, construction-road, quarry and other types of self-propelled equipment where high traction and coupling properties and cross-country ability are required.

To increase the patency of self-propelled vehicles, the internal pressure in the tires is reduced, while the radial deflection of the tire and the contact patch of the tire with the road are increased. In this case, a greater number of tire tread pattern elements come into contact with the road and thereby the towing properties of the tire and the vehicle increase accordingly.

However, an increase in the radial deflection of the tire leads to an increase in stresses in the rubber of the tire sidewalls, especially multilayer ones. (see. Biderman V.L. "Car tires", M., 1963)

The invention is illustrated by drawings: in FIG. 12.

The proposed pneumatic tire consists of a carcass 1, sides 2 with side rings 3, sidewalls 4 and a breaker 5 of several layers of rubberized textile or metal cords and a tread 6 located behind it, having shoulder zones 7 and directional lugs 11.

The frame 1 is made of one or more complete rubberized layers 8 with a meridional direction of the threads, the edges of which are fixed on both sides in the zone of the side rings, one or more pairs of half layers 9 and 10, while one of the edges of each half layer ends and is fixed (wrapped) at side rings 3. The main layers 8 and half-layers 9, 10 can be made of both textile and metal cord threads. Each half-layer 9 and 10 is made continuously extending from the side 2 to the tread 6 and ends in the tread zone, while the half-layers do not intersect, do not overlap and do not overlap. The cord yarns 12 in the rubber-cord half-layers 9 and 10 on both sides of the equatorial plane in the circumferential direction are inclined at an angle to one side of the tire meridian, forming a "herringbone". For tires with a directional tread pattern 6 of an increased cross-country ability with grousers 11, the inclination of the cord threads in the half-layers 9 and 10 in the circumferential direction can be either opposite or coincide with the direction of the location of the grousers. Pneumatic tire works as follows. The tire on the vehicle must be mounted with the direction of inclination of the cord threads in half layers in the direction opposite to the direction of rotation of the wheel.

To do this, all tires with tread patterns of cross-country terrain are marked on the sidewall with the direction of rotation, for example, by imprinting from a vulcanization mold.

The inclination of the carcass filaments in half layers to one side of the meridian leads to different torsional stiffness in opposite directions of tire rotation.

In contrast to the diagonal (the threads in the carcass layers intersect) and radial tires, in which the torsional stiffness is almost the same when the tire is twisted by positive or negative torque, the torsional stiffness in the proposed design is not the same. It is greater in the case when the direction of the torque applied to the sides of the tire is an acute angle with the direction of the threads in the cords in the half-layers of the carcass (the direction of torque coincides with the direction of rotation of the tire), and less when the angle is obtuse (opposite directions).

In the first case, the torsional stiffness is determined by the stiffness of the carcass filaments in tensile half-layers, in the second, by the compressive stiffness of the side wall rubber (the compressive stiffness of the filaments is close to zero). Therefore, the internal losses in the first case will be significantly less than the internal losses in the second case.

The location of the tire on the vehicle so that the torque applied to the sides is an acute angle with the direction of the filaments in the half-layers of the carcass (torsional stiffness is maximum), improves the technical and economic performance of the vehicle, for example, loss of rolling, etc.

When a torque is applied to the tire in the opposite direction (obtuse angle) - a case of braking (braking torque), backward movement - internal losses are greater, braking distance is less.

The radial stiffness of the side walls of the tire carcass will increase or, accordingly, decrease when part of the layers of the radial layers of the carcass is replaced with half-layers.

In this design, one edge of the half layers is fixed in the side zone on the (y) side rings, and the other free edges of the half layers are located in the area under the tread. In this case, the free adjacent edges of the half layers do not intersect each other, the angle of inclination of the filaments in the half layers is 10-75 degrees, to the tire meridian.

Half-layers 9, 10 can be both below, between the main 8 full layers of the frame and above them, while the widths of half-layers located at different levels can be different, up to an overlap of one half-layer on top of another adjacent through the main layer of the frame.

Also, the free edges of the half layers can be located above the layers or between the layers of the tire breaker 5. The overlap (overlap) of the half-layers of the frame with the edges of the layers of the belt should be at least 10 mm.

When the multilayer tire is radially loaded, the cord filaments of the inner layers of the carcass located along the meridian fall into the compression zone. The filaments of the cord of the outer layers are stretched, i.e. loaded. When compressed, the textile threads of the cord have practically no stiffness.

If there are cords in the carcass with a direction different from the radial direction of the tire, when loaded with a radial load, the tire deflection is reduced. Part of the threads in the frame, mainly in the half-layers, begins to work in tension. The radial stiffness of the tire increases, the changes of which are determined by the angle of inclination of the cord threads in half layers and the mechanical (stiff) properties of these cords themselves and the number of layers.

The stiffness also increases in the shoulder area of the tire (breaker edge.) It is possible to use 6 textile cords with different hardness properties in the carcass.

The variation of the angles of inclination of the cord 12 in the half layers, the frequency (density) of the location of the threads in the half layers allows the tire designer to obtain optimal values for the radial stiffness of the tire. It should be noted that the angle of inclination of the filaments 12 in the half-layers is a variable and is determined by the closing angle and the distance from the bead.

To optimize the tire stiffness on the treadmill, a more significant change in the width of the breaker layers and their number is possible.

The sidewall rubber in radial tires operates in a flat biaxial tensile mode, in the presence of half-layers with threads spread at an angle to the tire’s meridional plane, the loading mode of the coating rubber goes into the “diamond” mode. On one rhombus axis we have a stretching mode, on the other rhombus axis a compression mode. This is a more optimal loading mode for tire coverslips. This fact contributes to a higher performance of the coating rubber, which is more important when reducing the internal pressure in the tire.

In general, taking into account the fact that it is possible to vary the design parameters by the number, width of the breaker layers, the tilt angles and frequency of the cord in the breaker layers, the number of half-layers, the location of the free edges of the half-layers, the tilt angles and the frequency of the cord, types of cords, etc. the carcass designer has the ability to optimize the values of bending stiffness along the tire profile and the distribution of pressure in the contact patch of the tire with the road.

When changing (decreasing) the internal pressure in the tire in operation, such a constructive solution allows to reduce the values of the critical stress drop in the shoulder zones of the tire. Accordingly, increased resistance to mechanical damage and increases the performance of the tire as a whole.

Non-intersection of the half-layers of the carcass in the tread zone provides an increase in manufacturability in the production of tires (less slip of the half-layers when forming the tire at the 2nd stage and vulcanization of the tire).

Claims (1)

Pneumatic tire containing beads, side rings, sidewalls, tread, belt of several layers of rubberized textile or metal cords, a carcass with layers of rubberized cord with meridional direction of the threads in them, characterized in that in order to improve performance by increasing the traction and coupling properties when the internal pressure in the tire changes, part of the carcass layers is made in half layers, one edge of which is fixed to the / y side rings, and the other is located in the tread zone, while free to fittin g contiguous Semileaves not joined and tilt cords in the half-layers is formed in one side of the meridian (meridian section) of the tire at an angle of 10-75 degrees.

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