High-capacity vehicle tire with circular reinforcing elements

FIELD: transport.

SUBSTANCE: invention relates to pneumatic tire with radial carcass reinforcement including crown area reinforcement. Crown area consists of at least two layers. Crown area reinforcement is covered radially from above by the tread connected with two beads by two side strips. Reinforcing elements of circumferential reinforcing elements are composed of twisted cords with maximum tangential modulus of elasticity in out-of-tire state is smaller the maximum tangential modulus of elasticity I initial state by over 15 GPa, preferably, by 20 GPa.

EFFECT: higher fatigue strength.

14 cl, 2 dwg

 

The present invention relates to a tire with radial frame amplifier and, in particular, to the bus, intended for installation on vehicles that carry heavy loads and move from long supported speed, such as trucks, tractors, trailers or buses, which travel on the road.

Amplifiers or amplifier structural elements intended for tires and in particular for tyres of vehicles heavy vehicles, currently, as usual, formed from superimposed on each of one or more layers, usually known as "casing plies", "crown layers zone" etc. Is the name of the amplifiers comes from the method of manufacture, which consists in the manufacture of a range of semi-finished products in the form of plies, provided with thread-like reinforcing elements, often longitudinal, which then collect or impose on each other for assembling the blank of the tire. The layers are made flat, with large size and then cut to match the dimensions of the specified product. Layers also harvested the source is essentially flat. Thereafter, thus obtained the workpiece give a toroidal profile, typical for tires. Semi-finished products, known as products to complete fabrication, then put on just the internals to get the product, which is ready for vulcanization.

The way the "normal" type, such as this implies, in particular, during the production phases of the procurement of bus, using fastening element (typically, a bead wire), which is used for fastening or fixing frame amp in the area of the sides of the tire. Thus, in the way of this type of all layers (or only some of the layers, which form a frame amplifier, is wound around the bead wire, located in the Board the bus. Thus, the frame power fix in the Board.

The fact that the method of this conventional type is widely distributed in the tire industry, despite the availability of numerous alternative ways of making layers and kits, led specialists in the art to use a dictionary, depending on the way; hence the generally accepted terminology, which, in particular, includes the terms "layers", "carcass", "bead wire", "shaping" to indicate the transition from a flat profile to a toroidal profile, etc.

Currently, there are tires that are not, strictly speaking, have no "layers" or "bead wires", which correspond to the above definitions. For example, in the publication EP 0582196 described tires manufactured without the use of polugar is cut in layers. For example, the reinforcing elements of different reinforcing structural elements imposed directly on the adjacent layers of rubber mixtures, all of this is put in the form of successive layers on the toroidal core, the shape of which provides the ability to directly obtain a profile similar to the end profile of manufactured tires. Thus, in this case there are no "half" or any "layers", or any "bead wires". Source products such as rubber and reinforcing members in the form of threads or elementary fibers, imposed directly on the core. Since the core has a toroidal shape, there is no longer any need to give the workpiece a definite shape to change its profile from a flat profile to a profile in the shape of a torus.

In addition, bus, described in this publication, have no "traditional" winding layer of the carcass around the bead wire. The mount of this type is replaced by a construction in which the peripheral cutting thread located next to the specified amplification element of the sidewalls, all of which terminates in a fastening or connecting the rubber mixture.

There are also ways to build on the toroidal core/mandrel, using semi-special the material adapted for quick, effective and simple accommodation in the Central core. Finally, it is also possible to use a hybrid approach, involving the use of certain semi-finished products for the formation of certain structural elements (such as layers, side wire, and so on), while other elements are formed by direct blending mixtures and/or amplifying elements.

In this publication to reflect the latest technological evolutions in the field of manufacturing and designing products, conventional terms such as "layers", "side wire" and so on, preferably replaced by terms that are neutral or do not depend on the type of method used. Thus, the term "amplifier frame type" or "amp sides" can be used as a reinforcing elements of the layer frame in the traditional way and the respective amplifying elements, usually placed on the side, in the tire manufactured in accordance with the method, which does not include the use of semi-finished products. The term "bonding"with his hand, can refer to a "traditional" winding layer of the carcass around the bead wire in the usual way, just as he may designate the complex is, educated circumferential reinforcing elements, the rubber mixture and the adjacent amplifying parts of the sidewalls in the lower zone, obtained by using a method which provides for the imposition on the toroidal core.

As a rule, in the tires of high capacity framed amplifier is fixed on each side in the bead area and on top of it in the radial direction, place the amplifier crown area, consisting at least of two layers, which are superimposed on each other and are formed of threads or cords which are parallel within each layer and crossed from one layer to the next, forming angles constituting from 10° to 45°, relative to the direction along the circumference. These layers, which form the operational amplifier, can also be covered with at least one layer, known as a protective layer and formed of reinforcement elements, which are preferably metallic and tensile and are known as elastic elements. It may also contain a layer of metal threads or cords with low elongation, forming an angle of 45° to 90°, relative to the direction along the circumference, with this layer, known as triangulation layer is located in the radial direction between the frame amplifier and the first layer to the hot zone, known as a working layer, formed of parallel yarns or cords arranged at angles that make up at most 45° in absolute value. Triangulation layer forms together with at least the specified working layer triangulated amplifier which is under the influence of different loads it will be subjected, is experiencing a minor deformation, while triangulation layer plays a significant role in resisting transverse compressive loads to which the totality of the amplifying elements is exposed in the crown area of the tire.

In the case of tires for large vehicles carrying capacity usually there is only one protective layer, and the protective elements in most cases are oriented in the same direction and the same angle in absolute value, which have reinforcing members farthest from the center in the radial direction and, therefore, adjacent in the radial direction, the working layer. In the case of tires for construction vehicles to move through fairly rough surfaces, the presence of two protective layers is preferred, while amplifying elements in adjacent layers intersect, and reinforcing members in the interior in the radial direction, the protective layer overlap with inextensible usilitel the mi elements in the outside in the radial direction, the working layer adjacent to the specified internal in the radial direction, and a protective layer.

Cords, as approved, are inextensible, when these cords are of elongation, comprising most of 0.2%, under the action of tensile forces, equal to 10% of the disruptive force.

Cords, as approved, are elastic, when these cords are of elongation, comprising at least 3%, under the action of tensile forces equal razryvnaya force, when the maximum shear module of elasticity which is less than 150 GPA.

Circumferential reinforcing elements are reinforcing members, which form angles within +2,5°, and 2.5° to approximately 0°, relative to the direction along the circumference.

Circumferential direction of the tire, or the longitudinal direction is a direction corresponding to the periphery of the tire and defined by the direction in which the moving bus.

The transverse or axial direction of the tire parallel to the axis of rotation of the tire.

A radial direction is a direction which intersects the axis of rotation of the tire and perpendicular to it.

The axis of rotation of the tire is the axis around which it rotates during normal use.

Radial or meridional plane is the plane that contains the axis of rotation the tires.

Circumferential median plane, or Equatorial plane, is a plane that is perpendicular to the axis of rotation of the tire and which divides the tire into two halves.

Some modern tires, known as the "road" tires are designed for driving high speed on increasingly long distances due to the improvements of the road network and due to the growth of the motorway network around the world. All the conditions under which a tire like this should work, no doubt, create the possibility of increasing the number of kilometers traveled, because tyre wear will be less, but, on the other hand, the fatigue endurance of this tire and, in particular, amplifier crown area as a result of this is reduced.

The reason for this is the presence of voltage in the amplifier crown area and, more precisely, the shear stresses between the layers of the crown zone, combined with a modest increase in the operating temperature at the ends of the shortest in the axial direction of the layer of the crown area, which can cause the appearance of cracks and their propagation in rubber on these ends. The same problem occurs at the edges of the two layers of reinforcing elements with the specified layer is not necessarily adjacent to the first layer in the radial direction.

To improve the fatigue endurance of the amplifier crown area of the tire rossmar is by the type of solutions have been proposed, related to the structure and quality of the layers and/or profiled elements of rubber mixtures, which are located between the ends and/or around the ends of the layers, and, more precisely, between the ends and/or around the ends of the layers, very short in the axial direction.

In the patent FR 1389428 to improve the resistance to deterioration of the characteristics of rubber compounds that are near the edges of the amplifier crown area, it is recommended to use together with nizkointensivnym tread rubber profiled element which covers at least side and the boundary edges of the amplifier crown area and consists of discogitasting rubber mixture.

In the patent FR 2222232 for elimination of layer separation/delamination amplifier crown zone provides for closing the ends of the amplifier strip of rubber, the hardness of which is on a scale of a shore differs from the corresponding characteristics of the tread located on top of the specified amplifier, and exceeds the hardness scale And Shor profiled element of rubber mix, which is located between the edges of the crown amplifier zones and layers of the frame of the amplifier.

In the application for French patent No. 2728510 proposed accommodation on the one hand, between the frame amplifier and the closest in the radial direction to the axis of rotation, the working layer of the amplifier crown area complianc is tion in the axial direction of the layer, formed of inextensible metal cords forming an angle amounting to at least 60°, relative to the direction along the circumference, and the width in the axial direction at least equal to the measured in an axial direction width of the shortest working crown layer zone, and, on the other hand, between two working crown layers of zone - an additional layer formed of metallic elements oriented essentially parallel to the direction along the circumference.

Prolonged use of tyres with a similar design, in the most severe conditions showed marginal characteristics from the point of view of fatigue endurance data buses.

To eliminate such drawbacks and improve the fatigue endurance of the amplifier crown area of these tires, it was suggested that at least one additional layer of reinforcement elements that are essentially parallel to the direction along the circumference, was provided in conjunction with the working crown layers zone at a certain angle. In particular, in the publication WO 99/24269 it was suggested that on each side of the Equatorial plane and as a direct continuation of an additional layer of reinforcement elements that are essentially parallel in the circumferential direction, in the axial directed the two working crown layer zone, formed of reinforcement elements, which are crossed from one layer to another, were connected at some distance in the axial direction and is then separated from each other or disconnected through the use of profiled elements of rubber mix, at least in the remainder of the width common to the said two working layers.

One object of the invention is to develop tyres that are designed for vehicles of high capacity/heavy vehicles, fatigue endurance which further enhanced, particularly in the most severe operating conditions.

This task is solved in accordance with the invention through the use of tires with radial frame steering containing the amplifier crown area formed from at least two working crown layers of the zone, formed of inextensible reinforcement elements, which are crossed from one layer to the next, forming angles constituting from 10° to 45°, relative to the direction along the circumference, in this case, the amplifier crown area is closed at the top in the radial direction of the protector, and the protector is connected to the two sides by means of two sidewalls, the crown amplifier zone contains at least one layer of circumferential amplifying element is in, moreover, the reinforcing elements of the layer of circumferential reinforcing elements are twisted cords which have a maximum tangent modulus of elasticity in their condition when they are extracted from the tire is smaller than the maximum tangent modulus of elasticity in their original state for more than 15 GPA, and preferably more than 20 HPa.

Values of modulus of elasticity expressed above, measured on a curve of relative elongation from tensile stresses that are built with pre-load, part 5 H, while tensile stress corresponds to the tension divided by the cross sectional area of metal in the amplifying element. These measurements were carried out under tension in accordance with ISO in accordance with ISO 6892 of 1984.

Cords taken from the tyres, which made measurements taken from the tyre components which is different from the considered cords, and in particular mixtures affected the tendency to penetrate into these cords, are components that are common for applications of tyres for heavy vehicles/vehicles large capacity.

In accordance with the invention, the reinforcing elements of the layer of circumferential reinforcing elements preferably are twisted cords, which are harvested through with the person twisting, which provides the possibility of air ingress in the cord.

This method of twisting, in particular, may provide for twisting during the manufacture of the strands. In this case, the method of twisting essentially includes:

the winding of the filaments of the outer layer in the form of a spiral on the inner layer with a given time step, twisting,

- twisting or deformation to reduce the time step, i.e. to increase the angle of inclination of the helical line of the specified outer layer and, consequently, increasing the curvature of the spiral and

- stabilization of the strands obtained by untwisting, to obtain a zero residual torque.

The method of twisting can also refer to the formation of strands. Therefore, the method of twisting essentially includes:

- winding strands with a given time step, twisting,

- twisting or deformation to reduce the time step (i.e. to increase the angle of the helix bundle of strands and, therefore, increase the curvature of the helix), and

- stabilization of the cord obtained by untwisting, to obtain a zero residual torque.

The method of twisting ultimately may be a combination of twisting during the formation of each of the strands and twisting at the time of Assembly of strands for receiving the cord.

The method of twisting, described in a way which is implemented to receive the cord according to the invention, provides for making threads that form the outer layer of strands, and/or strands, which form a cord, the greater curvature, which provides separation in the axial direction (in this case, the axial direction is a direction, or perpendicular to the direction of the axis of the strands in the case of threads, or perpendicular to the direction of the axis of the cord in the case of strands). This curvature is determined, on the one hand, the diameter of the helix of the outer layer and, on the other hand, the helix pitch distance or even the angle of the helix of the outer layer (the angle measured relative to the axis of the cord).

It should be noted that the method of twisting, described thus provides the possibility to increase as the diameter of the helix and the pitch angle of the spiral.

In accordance with the invention the angle of inclination of the spiral/helix is preferably from 25° to 45°.

The method of twisting, described thus applied to the filaments, which form strands, and/or strands, plays a role in the significant increase in the structural extension cord, which is proportional to the square of the tangent of the angle of inclination of the spiral).

The inventors were able to demonstrate that the cords thus obtained, which are the reduction of the maximum tangent modulus of elasticity in their state, when they are removed from the bus, compared to their original condition exceeds 15 HPa, compared to the cord with the same formula, but obtained without the operation of twisting and lower steps of the spiral, have large structural elongation in the initial state and when they are removed from the bus. In addition, while in their initial state are the same cords according to the invention, also in comparison with the cord with the same formula, but made without the operation of twisting and with fewer steps spirals have higher maximum shear modulus, the same cords in a state where they are extracted from the tire may have, much to our surprise, the smaller the maximum tangent modulus of elasticity in comparison with the cord with the same formula, but made without the operation of twisting and lower steps of the spiral.

Tires made thus in accordance with the invention can achieve an additional increase of the fatigue endurance, particularly in the most severe operating conditions.

The use of such reinforcing elements, at least one layer of circumferential reinforcing elements also provides the ability to maintain sufficient rigidity of the layer after molding and vulcanization in the usual processes.

In accordance with the tvii with one preferred embodiment of the invention reinforcing members, at least one layer of circumferential reinforcing elements are metal reinforcing elements having a secant modulus of elasticity at a relative elongation of 0.7%, amounting to from 10 to 120 GPA and a maximum tangent modulus of less than 150 GPA.

In accordance with the preferred embodiment secant modulus of elasticity of the reinforcement elements at a relative elongation of 0.7% is less than 100 GPA and preferably greater than 20 GPA, and even more preferably ranges from 30 to 90 GPA, and even more preferably less than 80 GPA.

The maximum tangent modulus of elasticity of the reinforcement elements is preferably less than 130 GPA, and even more preferably less than 120 GPA.

Values of modulus of elasticity expressed above, measured on a curve of relative elongation from tensile stresses that are built with pre-load, part 5 H, while tensile stress corresponds to the measured tension divided by the cross sectional area of metal in the amplifying element.

In accordance with a preferred embodiment of the reinforcement elements of at least one layer of circumferential reinforcing elements are metal reinforcing members having misaligned the Yu dependence of the relative elongation from tensile stress, which has gentle gradients for small relative movements and essentially constant and steep gradient for large relative movements. Such reinforcing elements of the additional layer is commonly known as "two" elements.

In accordance with a preferred embodiment of the invention a continuous and steep gradient appears, since the relative elongation, comprising from 0.4% to 0.7%.

Various characteristics of the amplifying elements, mentioned above, is defined for amplifying elements, taken from the tyres.

Reinforcing members, more suitable for the formation of at least one layer of circumferential reinforcement elements according to the invention, are at least sets with formula 21,23, the structure of which is: 3×(0,26+6×0,23) 5,0/7,5 SS (stainless steel); this twisted cord consists of 21 filament with the formula 3×(1+6), with 3 strands twisted together with 7.5 mm, with each strand is made up of 7 strands, namely from a single thread, forming the Central core with diameter equal 26/100 mm, and 6 strands with a diameter equal 23/100 mm, is wound with a pitch of 5 mm, Such a cord in its original state has a maximum tangent modulus of elasticity of 100 GPA, measured on a curve of relative elongation from plants is of concern to voltage, built in the pre-load component 5 H, while tensile stress corresponds to the measured tension divided by the cross sectional area of metal in the amplifying element. Cord removed from the bus and, therefore, includes rubber, has a maximum tangent modulus of elasticity equal to 78 GPA, measured on a curve of relative elongation from tensile stresses that are built with pre-load, part 5 N, and tensile stress corresponds to the measured tension divided by the cross sectional area of metal in the amplifying element.

In accordance with a preferred alternative embodiment of the invention the ratio of the distance between the limiting surface wear and reinforcing elements of the layer of circumferential reinforcing elements in the circumferential median plane to the distance between the limiting surface wear and reinforcing elements of the layer of circumferential reinforcing elements at the ends of the specified layer of circumferential reinforcing elements is from 0.95 to 1.05.

With regard to the invention of the marginal surface of the wear of the tire is defined as the surface obtained by extrapolation from the wear indicators, available on the bus.

The distance between the limit surface and the nose and reinforcing elements of the layer of circumferential reinforcing elements is measured along the normal to the outer surface of the tread, which passes through the corresponding measuring point for the layer circumferential reinforcing elements.

Various measurements were performed in the cross section of the tire when the tire is deflated.

In accordance with this alternative embodiment of the invention, the architecture of the amplifier in the zone unit crown area of the tire, i.e. in the area under the protector, takes the form of the reinforcement layers frame the amplifier and amplifying layers amplifier crown zone, the radii of curvature of which in the axial (or longitudinal) direction is almost identical at all points on the profile surface wear and, therefore, identical to the radius of the tread.

In the case of this alternative embodiment of the invention in which reinforcing layers amplifier crown area have a curvature in the axial direction, which provides almost all points concentricity relative to the tread profile, the use of cords according to the invention provides the ability to further increase the fatigue endurance of the tire. In particular, significantly lower modulus cords extracted from the tire in combination with a large structural elongation compared to the cord with the same formula, but obtained without the operation of twisting and lower steps of the spiral, making the possibility of reducing tensions, exposed reinforcing members in the circumferential layer of reinforcing elements, particularly at the ends of the specified layer when the layer has a curved shape, as in the invention, when passing through the contact patch, which causes deformation of the tire.

In accordance with the invention preferably provides at least one layer, which forms a structural element of the crown area, which should be in the radial direction under the farthest from the center in the axial direction "edge" or directed mainly in the longitudinal direction of the tread. This alternative implementation provides increased rigidity of the tread pattern.

In accordance with a preferred embodiment of the invention, the difference measured in the axial direction of the width of the widest in the axial direction, the working layer of the crown area and measured in the axial direction of the width of the most narrow in the axial direction, the working crown layer is from 10 to 30 mm

Also preferably, if the widest in the axial direction of the working crown layer zone is located in the radial direction from the inner side of the other working crown layers of the zone.

In one preferred embodiment of the invention measured in xylinum the width direction, at least one layer of circumferential reinforcing elements is less than measured in the axial direction of the width of the widest in the axial direction of the working layer of the crown area.

As the width of the at least one layer of circumferential reinforcing elements, in particular, allows to reduce the shear stress between the working layers and, therefore, provides an additional increase in fatigue endurance of the tire.

The layer of circumferential reinforcement elements according to the invention preferably is a layer, which is continuous throughout its width in the axial direction.

In accordance with an alternative embodiment of the invention, at least one layer of circumferential reinforcing elements superimposed radially between two working crown layers of the zone.

In accordance with this alternative embodiment, the layer of circumferential reinforcing elements provides the possibility of more severe restrictions compression reinforcement elements in the frame amplifier compared to the same layer superposed in the radial direction from the outer side of the working layers. It is preferably separated in a radial direction from the frame of the amplifier, at least one working layer to reduce the load pointed to by the x amplifier elements and for in order not to expose them to excessive fatigue.

In the case of a layer of circumferential reinforcement elements, which is located radially between two working crown layers, also preferably measured in the axial direction of the width of the working crown layers area, adjacent in the radial direction with a layer of circumferential reinforcement elements, were more measured in axial direction of the width of the specified layer of circumferential reinforcement elements, and preferably, these layers corona zone, adjacent to the layer of circumferential reinforcement elements on each side of the Equatorial plane and on the direct continuation in the axial direction of the layer of circumferential reinforcing elements were connected to a certain width in the axial direction and then the separated profiled elements of rubber mix, at least in the remainder of the width common to the said two working layers.

The presence of such connections between the working layers of the crown zone, adjacent to the layer of circumferential reinforcing elements can further reduce the tensile stress acting on the most distant from the center in the axial direction, circumferential elements located closest to the connection.

The thickness of the profiled elements,which provide the separation between the working layers, measured at the ends of the narrow working layer was equal to at least two millimeters and preferably exceed 2.5 mm

Under the United layers should understand the layers corresponding reinforcing members which are located at a distance from each other in the radial direction, constituting at most 1.5 mm, while the thickness of the rubber is measured in the radial direction respectively between the upper and lower forming these reinforcing elements.

To reduce the tensile stresses acting on the most distant from the center in the axial direction, circumferential elements, in accordance with the invention also preferably provided so that the angle formed by the reinforcing elements of the working crown layers of the zone relative to the direction along the circumference, was less than 30° and preferably less than 25°.

In accordance with another preferred alternative implementation of the working crown layers of zones contain reinforcing elements, which are crossed from one layer to another and form angles relative to the direction along the circumference, which can vary in the axial direction, the angles more on the outside in the axial direction of the edges of the layers of reinforcement elements compared to the angles of these elements, change the n in the circumferential median plane. Such a variant embodiment of the invention provides the possibility of increasing the rigidity in the circumferential direction in certain areas, but decrease it in other areas, in particular, to reduce the compressive loads acting on the frame amplifier.

In one preferred embodiment of the invention the amplifier crown area also extended in the radial direction from the outside, at least one additional layer, known as the protective layer of reinforcement elements, which, allegedly, are elastic, which are directed at an angle constituting from 10° to 45°, relative to the direction along the circumference, and in the same direction as the angle formed by the inextensible elements of the working layer adjacent in the radial direction.

The protective layer may have a width in the axial direction which is less than the measured in the axial direction of the width of the narrowest working ply. The protective layer may also have a width in the axial direction, which exceeds measured in axial direction of the width of the narrowest working layer, so that it will overlap the sides of the narrow working layer, and if it is the top in the radial direction of the layer is the most narrow, it will be connected on the continuation in the axial direction additional the aqueous amplifier with the widest working crown layer area at a certain width in the axial direction and then from the outside in the axial direction will be separated from the specified widest working layer of profiled elements with thickness, component, at least 2 mm, a Protective layer formed of the elastic reinforcing elements, in the above cases may be, on the one hand, perhaps separated from the edges of the narrow working layer of profiled elements with a thickness that is substantially less than the thickness of the profiled elements, which separate the edges of the two working layers from each other, and, on the other hand, may have the width in the axial direction which is less than or greater as measured in the axial direction of the width of the widest layer of the crown area.

In accordance with any one of the two embodiments of the invention mentioned above, the amplifier crown area can be, in addition, supplemented located in the radial direction from the inner side between the frame steering and interior in the radial direction of the working layer that is located closest to the frame amplifier, triangulation layer of inextensible metal reinforcing elements made of steel, which form an angle greater than 60°, relative to the direction along the district the tee and in the same direction, as the direction of the angle formed by the reinforcing elements from the nearest in the radial direction of the layer frame of the amplifier.

Other preferred features and details of the invention will become apparent hereinafter from the description of one variant of the invention, given with reference to figures 1 and 2, on which:

figure 1 is a longitudinal schematic view of a tire in accordance with the invention; and

figure 2 is a graph showing curves of relative elongation from efforts to cords according to the invention and conventional cords.

To facilitate understanding 1 is not drawn to scale. Figure 1 shows a view of only half of the bus, which continues symmetrically with respect to axis XX', which displays the circumferential median plane, or Equatorial plane of the tire.

In figure 1, the tire 1 with the size 315/70 R 22.5 XF has a ratio H/S height of the tire section width is equal to 0.70, while H is the height of the tire 1 at the destined rim and S - maximum width of the tire in the axial direction. The tire 1 has a radial frame amplifier 2, mounted in the two sides, not shown in the drawing. Framed amplifier formed of a single layer of metal cords. Frame amplifier 2 is wound with crown amplifier 4 zones formed in the radial direction from the inside to the outside:

- the C of the first working layer 41, formed from neymotin inextensible metal cords 11,35 that are continuous on the entire width of the layer and is directed at an angle equal to 18°,

- layer of circumferential reinforcing elements 42, which is formed of metal cords 21×23, made of steel and representing cords "two" type,

from the second working layer 43 formed of neymotin inextensible metal cords 11,35 that are continuous on the entire width of the layer, is directed at an angle equal to 18°, and overlap with steel cord layer 41,

from the protective layer 44 made of an elastic metal cords 18×23.

The amplifier crown area is closed from above by the protector 5.

Measured in the axial direction width L41the first working layer 41 is equal to 248 mm, while the width for this tire normal shape substantially less than the width L of the tread, which in this case is equal to 262 mm Therefore, the difference between the width of the tread width and L41equal to 14 mm and, therefore, less than 15 mm in accordance with the invention.

Measured in the axial direction width L43the second working layer 43 is equal to 230 mm, the difference between the widths of the L41and L43equal to 18 mm and, therefore, is from 10 to 30 mm in accordance with the invention.

As for the dimensions is measured in the axial direction of the width of the L 42the layer of circumferential reinforcing elements 42, then it is equal to 188 mm

The last layer 44 of the crown zone, known as the protective layer, has a width of L44equal to 188 mm

In accordance with the invention on the whole width of the layer of reinforcing elements 42 all layers of the amplifier crown area have a curvature, virtually ensuring concentricity relative to the protector.

Figure 1 also shows the marginal surface 3 of wear; it is obtained by extrapolation from the wear indicators, which are available in the bus, but which were not shown on the drawings.

In accordance with the invention, the ratio of the distance 6 between the maximum surface wear and reinforcing elements of the layer of circumferential reinforcing elements in the circumferential median plane to the distance 7 between the maximum surface wear and reinforcing elements of the layer of circumferential reinforcing elements at the ends of the layer of circumferential reinforcing elements is equal to 1 and, therefore, is from 0.95 to 1.05. In particular, distance 6, 7 between the maximum surface wear and reinforcing elements of the layer of circumferential reinforcing elements, respectively, in the circumferential median plane and on the ends of the specified layer of circumferential reinforcement elements are identical to each other and equal to 10 mm

Figure 2 is a graph showing the relative UD is inane from efforts to cord according to the invention, intended for the formation of a layer of circumferential reinforcement elements, which was formed by winding, as described earlier, compared with a cord with the same formula used more widely in the case of application of the given type.

This graph illustrates the relative elongation of 8 determined for tensile forces 9 applied to the Corda was in accordance with ISO 6892 (ISO 1984).

Cord according to the invention is a steel cord 21×23 "two" type, the construction of which is such: 3×(0,26+6×0,23) 5,0/7,5 SS (stainless steel); this twisted cord consists of 21 filament with the formula 3×(1+6), with 3 strands twisted together with 7.5 mm, while each strand is formed of 7 strands, namely from a single thread, forming a Central core with a diameter equal 26/100 mm, and 6 strands with a diameter equal 23/100 mm wound with a pitch of 5 mm

The control cord with which it is compared, is a steel cord "two" type with the same formula 21×23, with the design 3×(0,26+6×0,23) 4,4/6,6 SS (stainless steel).

Curve 10 corresponds Corda was according to the invention in its initial state, and curve 11 corresponds to the same Corda was retrieved from the bus, with this cord impregnated with rubber and underwent surgery vulcanization of the tire.

Similarly, curves 12 and 13 is sootvetstvuut control Corda was accordingly to its original state and condition, in which it is removed from the bus.

From these curves it is obvious that structural extension cord according to the invention exceeds the elongation of the control cord. In addition, the modulus of elasticity, or the maximum tangent modulus of elasticity of the cord according to the invention is equal to 100 HPa, while the maximum shear modulus of the control cord is equal to 90 GPA.

These differences in values can be explained by the formation method by twisting in the case of a cord according to the invention and the various steps in the formation, while these steps more in the case of a cord according to the invention.

In relation to the measurements made for cords extracted from the tire should indicate that the structural elongation of the cord according to the invention remains large, but the magnitude of the modulus of elasticity is smaller for the cord according to the invention compared with the modulus of the control cord, you have 78 GPA for the cord according to the invention compared to 85 GPA for the control cords.

Significantly lower maximum shear modulus for cords, removed from the tire, in combination with a large structural elongation compared to the cord with the same formula, but educated without surgery twisting and lower steps of the spiral, will provide an opportunity to reduce tensions that p is delaude reinforcing members in the circumferential layer of reinforcing elements passing through the contact patch, which causes the deformation of the tire, particularly at the ends of the specified layer.

In accordance with the invention, the maximum shear modulus cords according to the invention in the state in which they extracted from the tire is less than the maximum tangent modulus of elasticity in their original state by an amount equal to 22 HPa (100 - 78) and, therefore, greater than 15 GPA.

Tests were performed with a tire made in accordance with the invention according to the image in figure 1, containing the layer of circumferential reinforcing elements is formed with a reinforcing cord according to the invention, similar to the just described. Identical tests were conducted with the control bus, which was identical but was made with a different configuration, in which the cords of the layer of circumferential reinforcing elements represented the control cords described above.

Preliminary tests involved the implementation for each of the tires and ensure they follow the routes that are equivalent to straight-line trajectories, when the exposure of the tire to the load, heavier than the rated load for acceleration tests of this type.

The load for the control tire was 3600 kg at the beginning of the run and had risen to load 4350 kg at the end of the run.

The load bus is according to the invention was 3800 kg at the beginning of the run and had risen to load 4800 kg at the end of the run.

The results of these preliminary tests showed that the results obtained for the two types of tires were comparable, despite the fact that the tires according to the invention was subjected to large stresses.

Additional tests to determine the fatigue endurance were performed on the test installation, which provided the load application and the message of the rotation angle of the tire. These tests were performed for tires in accordance with the invention under load, which was 6% more, and a rotation, which was 10% higher compared with the load and the angle reported by the control bus.

The results again showed that the tyres are of two types showed very similar results, despite the fact that the tires according to the invention was subjected to greater stresses.

1. The radial frame steering containing the amplifier crown area formed from at least two working crown layers of the zone, made of inextensible reinforcement elements, which are crossed from one layer to the next, forming angles of between 10° to 45° relative to the direction along the circumference, in this case, the amplifier crown area is closed at the top in the radial direction of the protector, connected to the two sides by means of two sidewalls, being the m amplifier crown zone contains, at least one layer of circumferential reinforcement elements, characterized in thatthat reinforcing elements of the layer of circumferential reinforcing elements are twisted cords which have a maximum tangent modulus of elasticity in their condition when they are extracted from the tire is smaller than the maximum tangent modulus of elasticity in their original state for more than 15 GPA, and preferably more than 20 HPa.

2. The tire according to claim 1, characterized in that the reinforcing elements of at least one layer of circumferential reinforcing elements are metal reinforcing elements having a secant modulus of elasticity at a relative elongation of 0.7%, amounting to from 10 to 120 GPA and a maximum tangent modulus of less than 150 GPA.

3. The tire according to claim 2, characterized in that thethe secant modulus of elasticity of the reinforcement elements at a relative elongation of 0.7% is less than 100 GPA, preferably greater than 20 GPA, and even more preferably ranges from 30 to 90 GPA.

4. The tire according to claim 2 or 3, characterized in that thethe maximum tangent modulus of elasticity of the reinforcement elements is less than 130 GPA and preferably less than 120 GPA.

5. The tire according to one of claims 1 to 3, characterized in that thereinforcing elements of the layer of circumferential reinforcing elements are metallicheskie reinforcing members, with the curve of the dependence of the relative elongation from tensile stress, which has gentle gradients for small relative movements and essentially constant and steep gradient for large relative movements.

6. The tire according to one of claims 1 to 3, characterized in that the ratio of the distance between the limiting surface wear and reinforcing elements of the layer of circumferential reinforcing elements in the circumferential median plane to the distance between the limiting surface wear and reinforcing elements of the layer of circumferential reinforcing elements at the ends of the layer of circumferential reinforcing elements is from 0.95 to 1.05.

7. The tire according to one of claims 1 to 3, characterized in that thewide in the axial direction of the working crown layer zone is located in the radial direction from the inner side of the other working crown layers of the zone.

8. The tire according to one of claims 1 to 3, characterized in that thethe difference measured in the axial direction of the width of the widest in the axial direction of the working crown layer zone and measured in the axial direction of the width of the most narrow in the axial direction of the working crown layer is from 10 to 30 mm

9. The tire according to one of claims 1 to 3, characterized in that measured in the axial direction width of at least one layer of the district will increase the lnyh fewer items measured in the axial direction of the width of the widest in the axial direction of the working layer of the crown area.

10. The tire according to one of claims 1 to 3, characterized in that at least one layer of circumferential reinforcing elements superimposed radially between two working crown layers of the zone.

11. The tire of claim 10, characterized in that measured in the axial direction of the width of the working crown layers area, adjacent in the radial direction with a layer of circumferential reinforcement elements, exceed measured in axial direction of the width of the layer of circumferential reinforcing elements.

12. The tire according to claim 11, characterized in that the layers of the crown zone, adjacent to the layer of circumferential reinforcing elements; on each side of the Equatorial plane and on the direct continuation in the axial direction of the layer of circumferential reinforcing elements is connected at a certain width in the axial direction and then separated profiled elements of rubber mix, at least in the remainder of the width common to the said two working layers.

13. The tire according to one of claims 1 to 3, characterized in that the amplifier crown zones are expanded in the radial direction from the outside, at least one additional layer, known as the protective layer of reinforcement elements, which, allegedly, are elastic, which are directed at an angle constituting from 10° to 45°, relative to the direction along the environment and the particular, and in the same direction as the angle formed by the inextensible elements of the working layer adjacent in the radial direction.

14. The tire according to one of claims 1 to 3, characterized in that the amplifier crown zone further comprises a triangulation layer formed from a metal reinforcing elements, which form angles greater than 60°, relative to the direction along the circumference.



 

Same patents:

FIELD: transport.

SUBSTANCE: invention relates to pneumatic tire with radial carcass reinforcement including crown area reinforcement. Crown area consists of at least two layers. Crown area reinforcement is covered radially from above by the tread connected with two beads by two side strips. Ratio between crown area depth at shoulder end and crown area depth in circumferential median plane is larger than 1.20. Ratio between spacing between maximum wear surface and reinforcing elements in said plane and spacing between maximum wear of reinforcing elements at the ends of said layer of said elements varies from 0.95 to 1.05.

EFFECT: higher fatigue strength.

14 cl, 3 dwg

FIELD: transport.

SUBSTANCE: invention relates to automotive industry. Tire comprises tight rubber shell 2 and reinforcing structure composed of multiple fibres 30, 40 embedded in layer in rubber. Said reinforcement structure comprises, at least, carcass layer 3 and breaker layer 4. Fibres 30, 40 of said layers 3, 4 are jointed together and directed relative to tire middle plane (P) at angles varying from 90° to 0°. Every said fibre 30, 40 features flat cross-section.

EFFECT: simplified production.

20 cl, 7 dwg

Pneumatic tire // 2456168

FIELD: transport.

SUBSTANCE: invention relates to automotive industry. Tire carcass ply is laid between two double beads. Breaker ply is recessed on carcass ply outer peripheral side in tread section. Tread is provided with multiple main grooves extending along tire circle. Maximum depth of each main groove varies from 8.5 mm to 15.0 mm. Relationship between height of actual tire profile SH and that of profile SHstd calculated from tire size is set to 0.97≤α≤0.99. Relationship between contact areas makes 65-70% under conditions of measurements whereat air pressure makes 200 kPa and load making 50% of bearing capacity at said air pressure. Mean contact pressure P varies from 300 kPa to 400 kPa.

EFFECT: longer life, efficient braking on moistened surface.

13 cl, 4 dwg, 1 tbl

FIELD: transport.

SUBSTANCE: invention relates to automotive industry. Proposed tire features ellipticity factor equal to or under 50%. Breaker layers 9, apart from outer breaker layer 10, are arranged so that breaker layer cords are arranged at θ 10-70° relative to tire lengthwise direction. Said outer breaker layer 10 is made of coiled layer 12 of coiled tape provided with steel cords in tire lengthwise direction. Said breaker layer 10 comprises section 10A located between fold position Po on opposite sides from tire equator and fold position 10B bent in U-like manner from position Po toward tire equator. Section 10A features width varying from 70% to 80% of width of contact between tread and ground while fold section 10 B has width varying from 5.0 mm to 0.5 of width.

EFFECT: longer life.

9 cl, 8 dwg

Pneumatic tire // 2405682

FIELD: transport.

SUBSTANCE: invention relates to automotive industry, particularly to heavy-duty radial pneumatic tires of relatively small size ratios. Tire comprises toroidal carcass arranged atop two tire beads, undertread band arranged on outer side along carcass radial direction, and tread arranged on outer along radial direction of undertread belt. Undertread belt comprises at least one circular layer arranged on outer side along radial direction of carcass rim part and made up of multiple rubberised cords running along the tire equatorial axis, and at least two inclined layers of undertread belt arranged on circular layer of undertread belt, each being formed by multiple rubberised cords running inclined to tire equatorial axis O. Width of undertread belt circular layers makes at least 60% of the tire total width. Width of at least one inclined layer of undertread belt exceeds that of circular layer. Note that elasticity modulus of the first cords arranged on outer side of undertread belt circular layer is smaller than that of second cords arranged on inner side, across direction of the first cords.

EFFECT: longer life.

10 cl, 3 dwg

FIELD: transport.

SUBSTANCE: invention relates to automotive industry. Air tire has breaker structure that comprises first breaker layer (51), second breaker layer (52) arranged in radial-inner position relative to first breaker layer (51), third breaker layer (53) arranged in radial inner position relative to first (51) and second (52) breaker layers. Every breaker layer (51, 52, 53) comprises multiple elongated reinforcing elements arranged above 1st, 2nd and 3rd breaker angles. Note here that 1st and 2nd angles vary from 15 to 40 degrees. Second angle has opposite sign relative to 1st breaker angle. Third breaker angle features magnitude varying from 40 to 90 degrees and opposite sign with respect to second angle. Breaker structure comprises also breaker layer (54) arranged at zero degree angle relative to 1st breaker layer (51) comprising elongated reinforcing elements arranged to make, in fact, zero breaker angle,.

EFFECT: perfected performances.

21 cl, 11 dwg

FIELD: transport.

SUBSTANCE: proposed pneumatic tire incorporates a carcass and a tread formed by, at least, two tread layers made up of rigid reinforcing elements with alternating crossed-over layers forming, with the peripheral direction, the angles varying from 10° to 45° on the tread crown zone. The said tread crown zone is jointed to two beads by side walls. The tread side thickness-to-tread center thickness ratio makes below 1.20 and the tread crown zone-to-tire total width ratio exceeds or equals 0.89.

EFFECT: higher strength and reliability.

25 cl, 5 dwg

FIELD: transportation.

SUBSTANCE: invention is attributed to pneumatic tire for which factor of H/S type has value exceeding 0.55 and which has radial reinforcement of frame and contains flange reinforcement formed by at least two flange working layers created of inextensible reinforcing elements intercrossing from one layer to another forming with circumferential direction the angles in the range of 10 to 45°. Tyre tread connected with two beads by means of two sidewalls is located over this radial frame reinforcement in radial direction. Crest reinforcement contains at least one layer of circumferential reinforcing elements. Value of ratio of crest block width at the end of shoulder area to crest block width at center circumferential plane is less than 1.20, and value of ratio of axial width of at least one layer of circumferential reinforcing elements to axial width of tire tread exceeds 0.5 and preferably exceeds 0.6.

EFFECT: tire strength and reliability is improving.

23 cl, 5 dwg

FIELD: transportation.

SUBSTANCE: invention is attributed to pneumatic tire which has radial reinforcement of frame and contains crest reinforcement formed by at least two crest working layers created of inextensible reinforcing elements intercrossing from one layer to another forming with circumferential direction the angles in the range of 10 to 45°. Tire tread connected with two beads by means of two sidewalls is located over this radial frame reinforcement in radial direction. Crest reinforcement contains at least one layer of circumferential reinforcing elements which has axial width less than axial width of at least one of crest working layers. Ratio of axial width of at least one layer of circumferential reinforcing elements to axial width of tire tread is equal to value which exceeds 0.6 and preferentially exceeds 0.65. Ratio of tire tread axial width to maximum axial width of this pneumatic tire is equal to value exceeding 0.89.

EFFECT: tire strength and reliability is improving.

17 cl, 5 dwg

FIELD: transport engineering.

SUBSTANCE: invention relates to pneumatic tyre with radial carcass reinforcement over which ridge reinforcement consisting of at least two working layers of ridge formed by metal reinforcement members is arranged in radial direction. Said reinforcement members intersect from one layer to the other forming angles of 10 to 35° with circumferential direction. Ridge reinforcement includes at least one additional reinforcement formed by metal reinforcement members orientated in circumferential direction. Additional reinforcement consists of at least two layers of metal members of small diameter not exceeding 0.6 mm. Metal reinforcement members of additional reinforcement are assemblies, type 1 x n where n is from 2 to 5, made of steel featuring high breaking strength SHT, and diameter of threads is within 12/100 and 30/100.

EFFECT: increased strength and wear resistance of tyres.

10 cl, 3 dwg

FIELD: transport.

SUBSTANCE: invention relates to pneumatic tire with radial carcass reinforcement including crown area reinforcement. Crown area consists of at least two layers. Crown area reinforcement is covered radially from above by the tread connected with two beads by two side strips. Ratio between crown area depth at shoulder end and crown area depth in circumferential median plane is larger than 1.20. Ratio between spacing between maximum wear surface and reinforcing elements in said plane and spacing between maximum wear of reinforcing elements at the ends of said layer of said elements varies from 0.95 to 1.05.

EFFECT: higher fatigue strength.

14 cl, 3 dwg

Pneumatic tire case // 2495761

FIELD: transport.

SUBSTANCE: invention relates to automotive industry, particularly, to car and light truck tires. Tire case comprises tread, belt play consists of metal cord and textile plies, carcass, side strip and bead ring. Metal cord diameter makes 0.55-0.95 mm. Metal cord proper is composed of equal-diameter metal threads. Note here that metal threaded diameter-to-metal cord diameter makes 0.344-0.543, rubberised metal cord pitch makes 1.052-2.083, while metal cord linear density varies from 1.05 to 2.67 g/m. Note also that thickness of every rubberised metal cord ply of breaker makes 0.72-1.52 mm, while metal cord breaking strength is not lower than 400-900±5 N.

EFFECT: lower metal and labor input, electric power savings.

2 dwg

Pneumatic tire case // 2495760

FIELD: transport.

SUBSTANCE: invention relates to automotive industry, particularly, to car and light truck tires. Tire case comprises tread, belt play consists of metal cord and textile plies, carcass, side strip and bead ring. Metal cord diameter makes 0.57-0.63 mm. Metal cord proper is composed of equal-diameter metal threads. Note here that metal threaded diameter-to-metal cord diameter makes 0.460-0.543, metal cord linear density varies from 1.06 to 1.18 g/m. Note also that thickness of every rubberised metal cord ply of breaker makes 0.75-1.45 mm, while metal cord breaking strength is not lower than 400±5 N.

EFFECT: lower metal and labor input, electric power savings.

2 dwg

Air tire cover // 2467884

FIELD: transport.

SUBSTANCE: invention relates to automotive tires, particularly, to truck radial tires. Proposed cover comprises tread, breaker composed of metal cord and textile layers, carcass, side strips, and bead rings. Metal cord diameter is 0.81-0.90 mm. Metal cord made up of metal threads of equal diameter of 0.31-0.33 mm. Relationship between metal cord spacing in rubberised breaker layer and metal cord diameter makes 1.55-2.22 while linear density of metal cord equals 2.35-2.70 g/m. Note here that relationship between every metal cord rubberized layer in breaker and metal cord diameter makes 1.39-1.74. Note also that thickness of every metal cord rubberised layer in breaker is 1.2-1.5 mm while metal cord tensile strength is not lower than 885±5N.

EFFECT: higher tensile strength and linear density.

2 dwg

FIELD: transport.

SUBSTANCE: invention relates to automotive industry. Proposed tire features ellipticity factor equal to or under 50%. Breaker layers 9, apart from outer breaker layer 10, are arranged so that breaker layer cords are arranged at θ 10-70° relative to tire lengthwise direction. Said outer breaker layer 10 is made of coiled layer 12 of coiled tape provided with steel cords in tire lengthwise direction. Said breaker layer 10 comprises section 10A located between fold position Po on opposite sides from tire equator and fold position 10B bent in U-like manner from position Po toward tire equator. Section 10A features width varying from 70% to 80% of width of contact between tread and ground while fold section 10 B has width varying from 5.0 mm to 0.5 of width.

EFFECT: longer life.

9 cl, 8 dwg

Tire case // 2422291

FIELD: transport.

SUBSTANCE: invention relates to automotive industry, particularly, to design of truck radial tires. A case contains tread, breaker consisting of metal-cord and textile layers, casing, sidewalls and bead rings. Metal cord diameter is 0.77-0.85 mm. The metal cord itself is made of metal fibers with equal diameter, and the ratio of metal fiber to metal cord diameter is 0.330-0.410. The ratio of metal cord in rubber-covered breaker layer to metal cord is 2.057-2.743, and linear density of metal cord lays within the range of 2.12-2.34 g/m. Herewith, the thickness of each rubber-covered metal cord layer in breaker is 1.25-1.45 mm, and tensile strength of metal cord is not lower than 875±5 N.

EFFECT: material, labor and energy consumption of tire manufacturing is lowered.

2 dwg

FIELD: transport.

SUBSTANCE: invention relates to automotive industry. Air tire has breaker structure that comprises first breaker layer (51), second breaker layer (52) arranged in radial-inner position relative to first breaker layer (51), third breaker layer (53) arranged in radial inner position relative to first (51) and second (52) breaker layers. Every breaker layer (51, 52, 53) comprises multiple elongated reinforcing elements arranged above 1st, 2nd and 3rd breaker angles. Note here that 1st and 2nd angles vary from 15 to 40 degrees. Second angle has opposite sign relative to 1st breaker angle. Third breaker angle features magnitude varying from 40 to 90 degrees and opposite sign with respect to second angle. Breaker structure comprises also breaker layer (54) arranged at zero degree angle relative to 1st breaker layer (51) comprising elongated reinforcing elements arranged to make, in fact, zero breaker angle,.

EFFECT: perfected performances.

21 cl, 11 dwg

FIELD: tire industry.

SUBSTANCE: invention relates to tire with radial reinforcement of carcass for use on heavy vehicles, such as transport or construction and road-building machines. It relates to tire with axial width exceeding 37 inches. According to invention, tire has working reinforcement crown consisting of at least two uninterrupted working layers and terminating from each side of circumferential (equatorial) middle plane in at least two half-layers whose metal reinforcement members form angles exceeding minimum angle which is formed by reinforcement members of uninterrupted layers relative to circumferential direction. Half-layer passing in axial direction outwards further than other half-layers is in contact with widest in axial direction uninterrupted layer in crown, and two half-layers cover in radial direction axially outer end of said working layer widest in axial direction.

EFFECT: increased service life of tire.

8 cl, 4 dwg

FIELD: tire industry.

SUBSTANCE: invention relates to design of automobile tires, particularly to those used in construction vehicles. proposed reinforcement pack N of pneumatic tire contains reinforcement member embedded in converting materials and it includes first layer C1 and second layer C2 of metal elements E1, E2 parallel to each other and embedded into covering materials M1, M2 and third layer C3 of elements E3 made of textile material is placed between two layers C1 and C2, third layer being embedded into covering material M3. Textile elements E3 are orientated relative to elements E1 and E2 at angle within 70° and 110°.

EFFECT: increased strength of tires.

7 cl, 4 dwg

FIELD: automotive industry; tire industry.

SUBSTANCE: invention relates to tires for machines used in civil engineering. Proposed tire has radial carcass reinforcement 1 second in each bead by means of ring reinforcement member of bead and radially upper crown reinforcement containing at least two working layers of non-stretchable metal cord with intersecting threads of layers, width of said layers is at least 50% of tread width L, and radially upper two protective layers along crown made of so-called elastic metal cord with intersecting threads of layers. Tread includes, in its grooveless part of thickness D, at least one reinforcement made of strengthening members. Said reinforcement consists of at least two layers of textile monofiber whose threads are parallel in each layer. Axial width of said layers is at least equal to width of most narrow working layer.

EFFECT: increased strength of crow of pneumatic tire.

4 cl, 1 dwg

FIELD: automatic industry; tyre industry.

SUBSTANCE: invention relates to design of radial-ply tyres for trucks. Proposed tyre casing contains tread, breaker, carcass, side strips and bead rings. Diameter of metal cord is from 1.14 to 1.26 mm. Metal cord proper is made of equal-diameter metal threads, ratio of metal thread diameter to diameter of metal cord being from 0.253 to 0.298. Ratio of breaker metal cord pitch to diameter of metal cord is from 1.9 to 2.25, and linear density of metal cord lies within 5.0 and 5.5 g/m. Ratio of thickness of each rubber-lined layer of metal cord in breaker to diameter of metal cord is from 0.35 to 1.49, breaking strength of metal cord being not lower than 1715±5N.

EFFECT: reduced materials usage, labour input and energy consumption at production of tyres.

2 dwg

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