Fittings ridge pneumatic tyres

 

(57) Abstract:

The invention is intended for use in tires or heavy heavy-duty vehicles. The bus includes a valve frame formed of at least one layer of radial cord yarns, and the armature of the ridge formed at least one layer quasicylindrical form circumferential reinforcing elements. The latter consists of main metallic and inextensible cord yarns having a minimum transverse and radial dimensions at least equal 0,09 values of the square root of the magnitude of the district of radius R layer, the fill factor which is at least equal to 0.7 and on top of which in the radial direction is rubber element with a high modulus of elongation and with a cross-section in the form of a Crescent. The result is increased wear resistance of the tire. 8 C.p. f-crystals, 10 ill.

The invention relates to a pneumatic tire of the radial type, designed for heavy transport equipment, road-building and agricultural machinery, such as trucks, buses, trailers, road tractors, construction or agricultural tractors, etc. More accurately present isopetasin time consists of several vertex or Diablo layers. Usually, there are two so-called triangulation polsloe located on the valve frame on either side of the Equatorial plane of the pneumatic tire and composed of inextensible metal cord threads, forming with the circumferential direction an angle whose magnitude is in the range from 45o90oangular. On top of these triangulation polusaev are two layers of inextensible metal cord threads, crossed from one ply to the other and forming with the circumferential direction angles in the range from 10o30o. Two layers with a small angle, or so-called layers, padded top in the radial direction of at least one layer of tensile and elastic metal cord threads having generally the same direction as the underlying cord thread adjacent in the radial direction of the working layer. One or more layers of elastic cord yarns is a protective layers of reinforcement on this bus.

Such structure of the valve top or crest of the pneumatic tire can lead, especially in the case of severe operating conditions, the separation between the edges of the working layers of the ridge, and these edges ol mechanizirovannaya rubber, separating these regions, and to the separation of the working layers, up to the complete failure of the valve crest pneumatic tyres.

To resolve this problem have been proposed numerous technical solutions. So, for example, can be installed between the edges of the working layers of the ridge angle rubber profiles or pillows to reduce the above-mentioned shear stress between the layers.

In accordance with the hypothesis of tensile reinforcement ridge pneumatic tires as a function of inflation pressure will create a preliminary interlayer shear stress, rather adversely affect the resistance of the armature of the ridge. Therefore, it was proposed to place in the radial direction between the valve cage and valve crest at least two layers practically inextensible metal cord threads, forming with the circumferential direction of the small angle, preferably equal to 5oangular. These layers function as belt, firmly tightening the valve downstream of the radial carcass, which under the action of the internal pressure of the inflating pneumatic tires tends to increase its circumferential length, thus increasing its transverse curvature. And e is the specified pneumatic tire is disclosed, for example, in patent application FR France 2452390.

Inextensible cord thread above layers of contraction were consequently replaced by a tensile cord thread and the above-mentioned small angle was made zero or considered as zero, and mentioned layers are always installed between the valve cage and valve crest pneumatic tyres. Pneumatic tire of this design is described in application for U.S. patent number US 4934429.

The above technical solutions are quite expensive and sensitive to operating conditions, particularly for pneumatic tires, designed for installation on heavy-duty vehicle and having a shape factor less than unity. For a long time attempts have been made to replace the armature ridge pneumatic tire formed by overlapping layers cord yarns or mixed reinforcement ridge formed by overlapping layers of cord strands and layers of circumferential cord threads on the valve, formed exclusively by the supporting elements.

In the French patent FR 1198141 described pneumatic tire, having a nearly cylindrical outer surface the fastening or tightening, formed by one or more circumferential reinforcing elements embedded or encapsulated in a plastic material.

In the French patent FR 2429678 described the valves of the district of cord threads for pneumatic tires, the shape factor which has a value in the range of from 0.40 to 0.65, and this valve is formed by winding cord thread spiral with a pitch that varies from 1 to 4 diameters this cord thread.

In the application for the European patent EP 0093451 A2, after mentioning that the authors refused exclusive use of district cord yarns for forming a reinforcement ridge pneumatic tyres in favour of the reinforcement of more complex design, which allows to provide lateral stiffness sufficient to resist the action of transverse forces, which is subjected to a pneumatic tyre rolling with a lateral offset in certain operating conditions, however, it is then suggested that the structure of the valve of the crest of the district of cord threads, flooded or sealed in a layer of rubber with high modulus of elasticity, with very specific properties to improve performance and reduce rolling resistance pneumatophores and in the application for the European patent EP 0200055 A2 with the obvious aim to improve the characterization of the behavior of pneumatic tires, changing the direction of movement of the wheel, equipped with a tire described in the aforementioned application EP patent.

In U.S. patent US 4691752 with the aim of reducing or even eliminating the lateral pushing force in a zero offset wheel, which is more generally referred to as the "ply-steer, a combination of ridge layer of circumferential cord yarns with a compression zone formed by the layer of rubber, reinforced by short fibers, and having a tensile strength at least equal to 10 kg/mm2.

In the application for the European patent EP 0280674 A2 describes a pneumatic tire containing the valve of crest, consisting of at least three layers of metal reinforcing elements and located between the radial reinforcement frame and the treadmill this bus, and at least one of these layers is located between one of the inner radial direction of the layer and one outer in the radial direction of the layer. This valve ridge formed by two side parts between which there is a special layer of rubber. For this rubber hardness shore a has a value of at least ten points lower than the shore hardness for rubber compounds used in the layers of the ridge. Uprofil type optical lens.

Technical solutions described in the above-mentioned documents do not provide sufficient level of resistance to wear for pneumatic tires for heavy-duty or heavy-duty vehicles having a shape factor less than unity, while maintaining a very high overall strength. The installation of such pneumatic tires can improve the characteristics of the behavior on the road are equipped their vehicles, in particular in the case when it comes to minimizing the effects connected with the presence on the road grooves, ruts, or bumps.

The present invention is the task of solving the problem of separation between the reinforcement layers of the ridge and to ensure a sufficiently high resistance to wear, satisfactory behaviour of the tyres on the road, as well as reduced resistance to this bus rolling.

Features pneumatic tire containing the valve frame formed of at least one layer radial cable threads, and the valve of the ridge formed at least one layer of solid reinforcing elements, on top of which in the radial direction are several layers of rubber, including a Jogging track tires, Prov, and on top of this layer is a rubber element in the form of a lens and with a cross-section in the shape of a croissant, a maximum thickness which is at least equal to the maximum size in the radial direction of the main supporting elements, and the width in the axial direction does not exceed 80% of the axial width of the layer of these reinforcing elements, characterized in that the main supporting elements are inextensible circumferential elements, which are optionally separated by the secondary elements, and referred to the main reinforcing elements have a minimum transverse and radial dimensions at least equal 0,09 values of the square root of the magnitude of the district of radius Rsmentioned layer, and this layer is the main reinforcing elements has a fill factor at least equal to 0.70 and the width in the axial direction at least equal to 0.70 S, where S represents the maximum axial width of this pneumatic tire mounted on the destined wheel rim and inflated to operating pressure, and at least equal to 90% of the axial width of the tread and the rubber lens has a secant modulesa elements is called quasicylindrical in the case if the radius of transverse curvature on the width defined for the rubber element in the form of lenses, at least three times greater than its circumferential radius Rsregardless of the convexity or concavity of this curvature.

The layer of circumferential reinforcing elements is a complex or composite system formed of reinforcing elements and rubber cover these reinforcing elements, and this rubber provides the ability to fill the space between the supporting elements and the formation over these elements and underneath the rubber layers strictly constant thickness. Themselves reinforcing elements may be solid, fractured or fragmented.

The fill factor of the layer represents the ratio of the volume occupied by this layer actually reinforcing elements, to its total volume. The layer of reinforcing elements may contain only the main supporting elements, i.e. elements that can withstand the efforts of tension, compression and bending caused by inflation of a pneumatic tire, flattening under load, and rolling this bus in a straight line and/or on the turn. The main supporting osszetevojenek by the formulaerN/Rsp, where Ter- the tension on the main supporting elements, N is the number of elements per centimeter layer, Rs- County radius of the layer and p is the pressure of the inflating pneumatic tires in bars.

In a preferred implementation, the fill factor of the layer can be increased in the presence of secondary reinforcing elements placed in the axial direction between the main elements and having such form that would provide an increase in the area of the so-called connective surfaces located opposite each other in the axial direction of the main reinforcing elements and secondary elements, which allows to increase the stiffness of shear between the main reinforcing elements and, consequently, increase the transverse rigidity of the reinforcement ridge.

The combination of the layer of circumferential reinforcing elements having the above characteristics, with the element in the form of lenses, made of rubber with high modulus of elongation, gives pneumatic tyre, good stability on the road, that is, the desired ratio of lateral forces acting on this pneumatic tire from the ground, led to the persistence compared with road resistance of pneumatic tyres with a single layer of the ridge, known from the prior art.

Road stability of the pneumatic tire in accordance with the invention can be enhanced in the presence of a rubber lens outside in the radial direction of at least one protective layer. This protective layer may be formed of cord threads oriented in relation to the district under the direction of some fragile , which can have a value in the range of 30o90othat generates residual lateral pushing force when the tire's rolling in a straight line and can be very favorable circumstance in some use cases.

The preferred design of the protective layer contains two protective polsloe localized in the axial direction on either side of the Equatorial plane of the pneumatic tire and formed metal cord threads, components with district direction for one polsloe angle + angle for another polsloe, and the angle is in the range of 30o60o. The corners, which form with the circumferential direction of the cord thread two polusaev may be different, for example, + for one polsloe and for other olukoya.

Other characteristics and advantages of the invention will be better understood from the following description with reference to the accompanying drawings, in which

Fig. 1 depicts a pneumatic tire (cut along the Meridian) according to the invention;

Fig. 2A-2E - sections of the different layers of the ridge pneumatic tyres (in section), which shows the interaction between the main reinforcing elements and the secondary p is Mature ridge pneumatic tyres (cut along the Meridian and top view) according to the invention;

Fig. 4A and 4B, other possible implementations of reinforcement ridge pneumatic tire according to the invention.

Pneumatic tyre (Fig.1) for heavy-duty or heavy-duty vehicles, corresponding to the size 315/50-22.5, has a shape factor defined by the ratio H/S is strictly equal to 0.50, and N and S are respectively the height and the maximum width in the axial direction of the pneumatic tyre, mounted on the destined wheel rim J and inflated to its operating pressure. Pneumatic tyre R contains the valve frame formed of a single layer of 1 cord of filaments of aromatic polyamide enshrined in each time you Board this bus by wrapping around the side of the ring 2 to form the wrapping 11.

The layer of reinforcement of the frame 1 is tightened the only layer of the ridge 3, formed by the supporting elements 30, which are circuitous and inextensible. These reinforcing elements 30 are metal cord thread, made of inextensible steel, i.e cord thread representing when exposed to a tensile stress of 10% from the efforts of the gap, relative Sousie with the circumferential direction an angle within the 0o2,5o. These cord thread in the absence of secondary reinforcing elements are cord thread having a relatively large cross-section compared with the cross-section cord yarns commonly used in pneumatic tires of such size to provide reliable confrontation, tension, resulting from inflating pneumatic tires up to operating pressure and multiplied by used in such cases, the safety factor for security.

Reinforcing elements 30 used in the fixture of the crest of the pneumatic tire in accordance with the invention, have a circular cross-section with a diameter of 2.8 mm, which corresponds to is 0.135 values of the square root of the magnitude of the district of radius Rslayer 3, and are in the described embodiment, the implementation of the cord threads of conventional type, i.e. cord thread formed the Central core, which is spirally wound a few strands of elementary fibers, and these strands of elementary fibers can be wound on the said core in multiple layers.

Layer 3 has an axial neprevezmou bus or 0.82 maximum width S of this pneumatic tire in the axial direction. Layer 3 adjacent in the radial direction to the layer frame 1 at a considerable width, whereas the edges of this layer 3 is separated from layer 1 rubber corner profiles 7.

On top of layer 3 in the radial direction is located rubber lens or cushion 4 in the shape of a Crescent, with a maximum thickness at the level of the Equatorial plane XX' of this pneumatic tyres 6 mm, i.e. 2.14 diameter cord yarns layer 3 circumferential reinforcing elements, and the width of the L1in the axial direction equal to 150 mm, or 61% of the width L of the layer 3.

Vulcanized rubber, which made the lens 4 has a secant modulus of rigidity under tension with 10% elongation is equal to 40 MPa. On top of the lens 4 is located rubber layer 5, are called the lower layer of the tread. The modulus of rigidity of the rubber of the layer is measured in the same conditions as mentioned above, does not exceed 6 MPa, i.e. has a value significantly smaller than the modulus for rubber lens 4.

Treadmill tread 6 complements the crest of this pneumatic tire and is connected to the sides of this pneumatic tire with 8 external and 9 internal rubber layers of the side walls.

In Fig. 2A CX is predlagaemym invention. Reinforcing elements 30 layer 3 are known from the current level of technology in this area is almost elliptic shape in cross section, but are located in this layer 3 so that the large axis of these elements were parallel to each other and parallel to the Equatorial plane XX' of the pneumatic tire.

The above-described preferred orientation of the main reinforcing elements helps to ensure the best connection between adjoining to each other elements due to the increased effective surface connections, i.e. full surface bonding of adjacent elements to the appropriate section of the separating rubber coating. Thus it is possible to obtain increased force General inter-element shift without increasing spot stresses at the connection level elements covering them with rubber.

Reinforcing elements 30 or cord thread with elliptical cross-section can be formed by a core 32 of arbitrary shape, made of plastic material or of metal, on which is wound one or more cord yarns from plastic material and/or metal, or a layer 33 of plastic material, or>The effective surface of the joint can be significantly increased as a result of presence between the two main supporting elements 30, which in the described embodiment are metal cord threads, secondary reinforcing elements 31, as shown in the various embodiments of Fig.2B-2D.

In Fig.2B secondary reinforcing element 31 is a metal lutunasobasoba tape a small thickness e, component in the considered implementation of 0.2 mm, and this tape is curved on the top and bottom end along the arc of a circle and wound up for the manufacture of the layer as well as the main supporting elements. This metal strip of rectangular cross-section can be glued to the rubber covering the main reinforcing elements 30, and can be fractionated or separated along the circumference of the layer 3. In a preferred embodiment, the implementation of this tape 31 has on its circumference a radial cut, alternating between the upper radial edge of the tape and its bottom in a radial direction of the edge.

In Fig. 2C schematically shows the secondary reinforcing element 31, having an optimized shape poperechnov the main reinforcing elements 30, i.e., the cord threads of round cross-section that allows for maximum surface connection and leave between side walls respectively of the secondary elements 31 and cord threads 30 nominal thickness of rubber, a width, which is strictly necessary for a sufficiently reliable coupling between the supporting elements and the coating rubber, and thus to provide the necessary strength pneumatic tyres.

The layer structure of the reinforcing elements, schematically shown in Fig.2D, is the most simple for industrial use as secondary reinforcing elements 31 are simply cord thread, made of metal or of plastic material and having a smaller diameter than the diameter of the main cord yarns 30, and each interval between the two main supporting elements are provided with two secondary reinforcing elements located on either side of the middle line of the layer 3 of the reinforcing elements.

The above three possible outcomes relate to the introduction of secondary reinforcing elements 31, separated from the main reinforcing element is levnymi reinforcing elements 30 so that as it is shown schematically in Fig.2E. Here is the major cord thread 30 are enclosed in appropriate wrappers, which can be made of plastic material, metal or elastomeric material with a high value of the modulus of elasticity or stiffness that allows you to give this system the reinforcing elements of the cross-sectional shape, the most suitable for creating rigidity in relation to the shift.

In Fig.3A and 3B schematically shows the preferred embodiment of the pneumatic tire in accordance with the invention. In this design from the outside in the radial direction with respect to the rubber lens 4 placed two polsloe 9', 9" of the so-called elastic or flexible metal cord threads. Metal cord thread called elastic or elastic in that case, if a tensile force equal to 10% of the efforts of the gap, it is the elongation at least equal to 0.5%. Mentioned polsloe are arranged symmetrically with respect to the Equatorial plane of the pneumatic tire from the point of view of their width, and from the point of view of the tilt angles of these polusaev. Thus polylog 9' problem angled +, costal is oriented at an angle -, components -45oand these polsloe can be asymmetric.

The width in the axial direction of each of these polusaev does not exceed 48% of the width of the compression layer 3 in the axial direction so that the outer axial ends of each of polusaev was located near the corresponding end of the layer 3, and the inner axial ends of these polusaev were separated from the Equatorial plane of the pneumatic tire clearance constituting at least 3% of the width L of the layer 3.

In Fig. 4A schematically shows an embodiment of the valve of the crest of the pneumatic tire in accordance with the invention, where over rubber lens 4 in the radial direction are two layers 10 cord yarns of aromatic polyamide, crossed from one ply to the other and forming with the circumferential direction an angle of 45o. This design allows, on the one hand, to significantly improve behavior on the road or heavy heavy-duty vehicles equipped with pneumatic tires, and on the other hand, to ensure adequate protection of the main valve crest pneumatic tyres, used on to the bus in accordance with the invention, schematically shown in Fig.4B differs from the variant shown in Fig.4A, the width of the layer 10. In this case, the width is somewhat smaller while maintaining the system of two layers of the same General width in the axial direction, but provides the crossed reinforcing elements only on the reduced width not exceeding 50% of the total width of 1.

1. Pneumatic tyre R containing the valve frame formed of at least one layer of radial cord yarns (1), and the armature of the ridge formed at least one layer (3) solid reinforcing elements, on top of which in the radial direction there are several layers of rubber, including the raceway protector (6), and quasicylindrical layer (3) of the reinforcing elements consists of a main metallic reinforcing elements (30), on top of which is located a rubber element (4) having a cross section in the shape of a Crescent with a maximum thickness, at least equal to the maximum size in the radial direction of the main supporting elements (30), and a width of L1in the axial direction, of not more than 80% of the axial width L of the layer (3) of the reinforcing elements, characterized in that the main elements (31), and the main supporting elements (30) have a minimum transverse and radial dimensions at least equal 0,09 values of the square root of the magnitude of the district of radius Rslayer (3), and this layer is the main reinforcing elements has a fill factor at least equal to 0.70 and the axial width L, is at least equal to 0.70 S, where S represents the maximum width in the axial direction of the pneumatic tyre, mounted on the destined wheel rim and inflated to the nominal operating pressure, and at least equal to 90% of the axial width Laboutof the tread.

2. Pneumatic tyre under item 1, characterized in that the fill factor is increased due to the presence of secondary reinforcing elements (31) placed in the axial direction between the main supporting elements (30) and having such a geometric shape to the connecting surface located against each other in the axial direction, the main supporting element (30) and a secondary element (31) were increased.

3. Pneumatic tyre under item 2, characterized in that the secondary elements (31) are latunirovannaya metal fractionated or separated along the circumference of the layer (3) or has on its circumference a radial cut alternating between the upper radial edge and the lower radial edge of this tape.

4. Pneumatic tyre under item 2, characterized in that the secondary reinforcing elements (31) are optimized cross-sectional shape, and the side walls are made parallel transverse contours of the main supporting elements (30) round cross-section to form between the side walls respectively of the secondary elements (31) and the main supporting element (30) clearance for rubber to obtain a sufficiently strong coupling between the supporting elements (30, 31) and rubber.

5. Pneumatic tyre under item 2, characterized in that the secondary reinforcing elements (31) are cord thread or wire made of metal or textile material, or plastic material, and having a diameter slightly less than the diameter of the cord threads of the main supporting elements (30).

6. Pneumatic tyre under item 2, characterized in that the secondary reinforcing elements (31) are directly connected with the main supporting elements (30), and elements (30) is covered with a special membrane made of is to give the system of these items cross-sectional shape, conducive to creating a rigidity with respect to shear strain.

7. Pneumatic tyre on one of the PP.1-6, characterized in that on the outside in the radial direction with respect to the rubber element (4) is placed at least one protective layer (10) formed of cord, wire or wires oriented in relation to the district direction at an angle in the range from 30 to 90o.

8. Pneumatic tyre under item 1, characterized in that it contains two of the protective layer (10) cord yarns or wires, elastic or not, crossed from one ply to the other and forming with the circumferential direction an angle of 45o.

9. Pneumatic tyre on one of the PP.1-6, characterized in that on top of the rubber lens (4) in the radial direction are two polsloe (9', 9") metallic elastic cord yarns oriented in relation to the district under the direction angle , and these layers are arranged symmetrically with respect to the Equatorial plane XX' of the pneumatic tire, and each of these layers has an axial width not exceeding 48% of the axial width L quasicylindrical layer (3) and the inner axial ends

 

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