CS210645B2 - Tyre and method of making the same - Google Patents

Description

The invention relates to a tire for wheels of all vehicles, i.e. passenger cars, vans, trucks and buses, earthmoving vehicles, airplanes, and a method for producing the same.

Tires use two types of scooters, with inserts with radial and crossed cords. The radial inserts consist of cord threads or fibers extending in the radial planes of the tire, while at the same time the carcass crown under the tire tread is separately reinforced. The flexibility of the radial inserts and the stiffness of the carcass crown have the well-known advantages of increased vehicle stability, reduced tire abrasion and greater driving comfort. However, the radial carcass of the casing also has drawbacks such as tire sidewall vulnerability, tire instability in certain circumstances, and limited maximum vehicle speed.

The crossed carcass consists of cord threads or fibers running obliquely to the radial planes of the tire in two mutually symmetrical directions, so that the cord threads are rhombuses whose one diagonal extends in the radial plane of the tire and whose contour shape and surface varies with distance tires, the sides of the diamond are always the same length. This type of carcass has the disadvantage that the carcass is reinforced too uniformly in the different areas of the tire, since the possibilities of varying the shape and area of the cord meshes are not so numerous that a suitable shape and area can be chosen for each area of the tire. As a result, it is not possible to simultaneously produce a low deformable tread and bead, especially in the circumferential direction and a very yielding sidewall of the carcass, especially in the radial direction.

These drawbacks are overcome by a carcass tire according to the invention consisting of two layers or two groups of cord thread layers extending from one bead to the other, wherein the threads in each layer or group of layers are parallel to each other and form a mesh of quadrangular meshes. two directions and form a different angle with the circumferential direction. SUMMARY OF THE INVENTION The yarns of one layer or group of layers form an angle which is greater in absolute circumference than the angle between the yarns of the other layer or group of layers and the circumferential direction. the angle α, after passing through a maximum value of 90 °, changes the sign, and starting from the beads of the tire3

The 210 645 maths reach both angles that are sharp in this area and have the same meaning, at the same time maximum values on the same circle and from it decrease to the top of the skeleton, the law according to which both angles change is the same from the outside to the tire.

Due to the unevenness of these angles, the course of the cord filaments of the carcass is unsymmetrical as opposed to the known cross-thread inserts where the mesh meshes have sides arranged symmetrically with respect to the circumferential or radial direction.

According to a further feature of the invention, at least over a portion of the carcass, the ratio R = sin α / sin β is constant and greater than 1. In this case, both sides of the meshes have a fixed length independent of distance from the tire casing axis.

The ratio R according to the invention is in the range of 1.1 to 10. Preferably the ratio R is greater than 2, in particular 2 to 5.

According to the invention, therefore, in the skeleton portion at the heel, the angle γ ₀ between the sides of the mesh of the mesh or the fill angle (180 ° -y ₀ ) has a value satisfying the relation sin γ g

VR ² —1

R and the sides of the eye extend in the same sense, that is, in the same quadrants defined by the circumferential and radial direction of the tire. Preferably, the magnitude of the angle γ is ₀ š

R ² —1

R ² + 1.

and hence the sum of the angles α ₀ , β _{0 at the} sides of the eye with the circumferential direction is less than 90 °. In the carcass section at the top of the tire, the angle γ $ between the sides of the eye or its fill (180— / s) has a value satisfying the condition ^ '+ γ ,. - 180 ° and thus in the part of the carcass at the apex and the bead of the tire, the meshes have the same area and the parallel threads have the same mutual distance.

According to the physical structure of the skeleton mesh layers, it is advantageous according to the invention if the yarns forming an angle β with the circumferential direction are more elastic than the yarns forming a greater angle with the circumferential direction and are arranged on their outer side and separated from them by a thin interlayer of rubber 2 to 5 MPa and 100% elongation.

According to a preferred embodiment of the invention, the greater angle is between 24½ ⁰ to 90 ° between the yarns and the circumferential direction, the smaller angle β between the yarns and the circumferential direction is 7½ ° to 18½ ° and the angle γ between the sides of the eye is 32 ° to 148 °.

The tire according to the invention is essentially different from conventional tires with radial and crossed cord threads in the carcass; it is less vulnerable and less deformable in the circumferential direction than the radial tire and allows greater sidewall deformation and greater tread and bead stiffness than tires with crossed cord threads in the liners. Using the carcass of the invention with a carcass without a crown-tread reinforcement, it gives better results than conventional cross-reinforcement, and when used with a crown-reinforcement, it is more efficient than a radial tire.

For example, it is suitable to choose cord threads, strands or elastic threads such as polyamide fibers, steel flexible or highly elastic wires for threads with a circumferential direction, while threads, strands or threads of low elasticity are preferred for larger angle threads. , such as rayon filaments, or conventional cord filaments, eg steel wires.

If the ratio R is greater than 2, the angle β cannot be greater than 30 °. If the ratio R is greater than 3, the angle β is less than 20 ° everywhere and even less than 19 °. This implies that one cord thread extends at all points of the carcass in a direction slightly different from the circumferential direction, while the other cord threads that cross them may locally extend radially at the sides of the carcass and may be at the carcass feet or carcass crown under the tread. run almost in the circumferential direction.

However, the ratio R cannot be too great if the degree of shrinkage t of the carcass skeleton, i.e. the ratio of the largest carcass diameter below the tread to the smallest carcass diameter, is still an acceptable value. Relationships or

Accordingly, a degree of accumulation of at least 1.5 must be selected to have an R ratio of less than 5, and even less than 3.5, to achieve a somewhat higher degree of accumulation.

In addition to the ratio R, another important parameter is the magnitude of the angle χ or (180 ° —χ] between adjacent sides of the mesh mesh. It is preferable that the angle γ varies within wide limits between the minimum angle χ ₀ at the skeleton feet and the maximum angle / _s below the tire tread.

In the tire manufacturing method of the present invention, at least two layers of cord threads are laid on each other on the ready-to-wear drum, which are parallel to each other but intersect with the threads of the second layer. around which the edges of the layers of cord threads fold and the preform is swollen. SUMMARY OF THE INVENTION The cord of the two layers is laid on the ready-to-wear web at unequal acute angles to the circumferential direction of the tire so that the workpiece is asymmetrical, and the side steel wires are allowed to rotate freely around the workpiece axis simultaneously. . Optionally, the cord yarns are laid on the ready-made drum at angles " ο, βο " which have the same meaning and whose sum is preferably less than 90 °. The cord thread according to the invention placed on a building drum under angles α _{0, β} ο, the ratio of the sines of "sin ce ₀

R-; _n sin β _α lies in the range 2 to 5, preferably 2.5 to 3.5, for example at 45 ° and 13 °.

Experience has shown that the carcass swelling proceeds without difficulty if the heel reinforcement ropes are allowed to rotate freely and the crossing points do not obstruct the rotation of the threads; at the same time, the carcass must not be adhered to the swelling member, for example on the swelling membrane. In this case, the mesh of the reinforcing mesh is transformed from the original state on the ready-made drum to the end-frame of the carcass while maintaining constant mesh lengths and, as a result, with a constant R = - sina / sin ^ ratio. .

The tire thus produced was tested and compared with a tire of the same dimensions, provided with a carcass with radially extending reinforcing cord threads. Both tire casings are equivalent in terms of driveability, durability and comfortable driving, although the carcass crown reinforcement under the tread and its designs have not been adapted to the new tire casing carcass type of the invention. A tire according to the invention, however, showed a considerable increase in the speed limit (from 217 to 267 km. Tr ^1), the rigidity of the side walls and the stability when driving straight.

BRIEF DESCRIPTION OF THE DRAWINGS The invention is illustrated in greater detail in the drawings, in which: FIG. 1 is a schematic radial cross-sectional view of the conventional diagonal carcass of the tire; FIG. 1A, 1B, 1C, IA ' two variants of successive shapes of basic mesh of rhombic mesh at various degrees of crowning, marked on the one hand by points A, B, C and on the other hand by points A ', B', C 'in Figs. 2 ', 2A, 2B, 2C, 2D and 2E show the mesh shape development in the planes A, B, C, D, E of Figures 2 and 2 3A, 3B to 3E, FIGS. 4A, 4B to 4E, FIGS. 5A, 5C, 5E, and FIGS. 6A, 6C, 6E illustrate other threads in the carcass of the invention. Fig. 7 shows a view of a tire building drum 2, FIG. 8 shows a skeleton of FIG. 7 is an axonometric view of a portion of the carcass after being bulged into the shape of FIG. 8 and FIG. 10 is a radial cross section of the tire casing of the invention.

In various figures, in particular Figures 7 to 10, each layer of mesh is shown with only a few, very spaced cord threads. In fact, in the tire casing, the reinforcing cord threads in each layer are much closer together.

Fig. 1 is a diagram of the formation of a carcass of a tire casing by a classic diamond crossover of reinforcing threads. It is assumed that all diamonds have a common side of the OZ and are drawn on the other sides of OA, OB, OC of the diamonds located in the tire planes A, B, C, shown schematically in Figure 1 ´. In Fig. 1, points A, B, C are of course on a common circle, since the sides of all diamonds are the same. The diagonals ZA, ZB, ZC of the diamonds extend parallel to the circumferential direction of the tire and their lengths are proportional to their distance from the tire axis. The ZC: ZA length ratio is the degree of crowning, ie the ratio of the distances of the outermost points C and A from the Z-Z axis of the tire.

As can be seen from Figs. ΙΑ, IB and 1C, the shapes and areas of the diamond meshes of a tire with a classic cross-ply cord change only little between the different planes; the density and circumferential stiffness of the skeleton are almost the same everywhere. Point C to point C may be moved to increase the density and stiffness of the meshes below the tread. In order to maintain the same degree of crowding, ie the same ZC 'to ZA' ratio, point A to A 'and point B to B' must be moved. This produces a more elongated mesh eye with a smaller area in the crown (Fig. 1C ´) and in the flank area at the tread. However, there is practically no change in the mesh in the plane of the carcass bead reinforcements (Fig. IA ´). Therefore, the density and orientation of the threads under the tread and the beads of the tire at the same time cannot be improved in this way, nor can unwanted increase in the density of the threads adjacent the tread be avoided.

Figures 2 to 2E show for comparison the advantages and possibilities of the reinforcing mesh of a tire according to the invention. A skeleton mesh formed of parallelogram meshes with sides having the same R ratio as the sine angle ratio is selected, wherein the selected R value is sin 45 ° / sin 13 ° = 3.144. This option simplifies the graphical representation of mesh shapes and areas.

Figures 2 to 2E are shown for the comparative OY meshes being invariant and the sides OA, OB, OC, OD, OE, meshes in the plane A, B, C, D, E of the tire schematically indicated in Fig. 2 are plotted. On the tire, the diagonals YA, YB, YC, YD, YE are parallel to the circumferential direction of the tire and their lengths are proportional to the distance from the tire's Y-Y axis. The degree of accumulation is given by the ratio YE: YA.

Giant. 2A, 2B, 2G, 2F, 2E show the course of the shapes and areas of the meshes, of which only half is shown in FIG. When moving from plane A to plane E, the long side OY of the parallelogram is only slightly inclined to the circumferential direction, with this small inclination increasing from plane A to plane B and then decreasing from plane B to planes C, D, and E. On the other hand, the shorter sides of the parallelograms OA, OB, OC, OD, OE have a much more pronounced slope, which increases from plane A to plane B and then decreases from plane B to planes C, D and E. very low slope, although the OE side has a steadily greater slope than the OY side. It can be seen that in plane B the side OB extends in the radial direction. In plane C, the sides of the parallelogram form a right angle and the eye has a maximum surface. In plane D, the sides of the eye have the same slope as in plane A, with an intermediate degree of transient YD: AY equal to 1.60, while in plane E, the eye area is the same as that of plane A at the final degree of EE: YA = 1.73. The change in the shape and area of the mesh of the mesh is therefore considerable.

2A-2E, the outline of the diamond meshes OAXZ, OBXZ, OCXZ, ODXZ, OEXZ having sides parallel to the sides of the parallelograms but of different lengths are shown in bold lines. It can be seen that the diagonals of the rhombuses, halving the angles at point O and at points A, B, C, D, and E, are inclined to the circumferential direction at an angle that is gradually 29 °, 54¼ ° 62½ °. 74 ° and 81 °. Thus, the diagonals of the diamonds move from the position of FIG. 2A to the position of FIG. 2E, i.e. from plane A to plane E, in a clockwise direction. The angled diamond mesh is formed at the same distance of opposite sides of the mesh meshes, i.e. the same distance between the cord threads of the two carcass layers of the tire casing.

FIGS. 3 and 6E show other examples analogous to those of FIGS. In the diagram in Fig. 3, R = 5 is selected, in Fig. 4 is R = 2, in Fig. 5 is R = 2.8, and in Fig. 6 is R = 2 , 3. They show cases with a ratio R relatively large (Figure 3) or small (Figure 4) and a ratio R medium with angles of deflection in the same direction, but with a sum less than 90 ° (Figure 5) or greater than 90 ° (Fig. 6) These various diagrams make it possible to see in particular the influence of the choice of the ratio R on the permissible degree of crowning, on the inclination of the cord threads of the mesh reinforcing meshes and on the variations in the meshes of these meshes.

Figures 7 to 10 show schematically the construction and structure of the tire casing 10 according to the invention, with dimensions of 165 X X 380 mm.

FIG. 7 shows a method of building the carcass of a tire casing on a building drum 1 provided with a diaphragm (not shown). A 1 mm thick layer of rubber 11 (FIG. 10) is applied to the ready-made drum 1, then a first cord layer of synthetic silk threads 12 rolled into the rubber. The cord threads 12 of this first layer lying close together are inclined to the left at an angle of 45 ° in the figure and the layer has a width of 345 mm. A 0.8 mm thick interlayer 13 of relatively hard rubber (modulus of elasticity of 3.5 MPa at 100% elongation) is then applied to the first cord layer. A second cord layer of polyamide threads 14 rolled into a suitable rubber is then applied thereto. This layer has a width of 355 mm and its yarns 14 lying close together also run at an angle of 13 ° to the left, i.e. in the same direction as the yarns 12. Finally, the side steel wires 15 spaced 279 mm apart and the gaskets 16 of steel Then, the edges of both the cord layers and the rubber layers 11, 13 are folded around the steel cables 15. After inserting the reinforcing steel cables 17 (FIG. 10) and applying the rubber sidewalls 18, the carcass of the tire casing is finished. 8, the diaphragm located between the skeleton skeleton and the building drum is inflated with compressed air, during which the steel ropes 15 must be allowed to move freely towards each other and rotate about the axis of the building drum, rotates them by a large angle up to 90 °.

After the carcass is finished, a rubber interlayer 19 is placed on its crown as indicated in FIG. 10, and a first reinforcement layer 20 of 134 mm width formed by steel wires inclined at 22 ° to the right is placed thereon, then a second rubber interlayer 21, a second a reinforcing layer 22 of 122 mm width, also consisting of steel wires but inclined at 19 ° to the left, and finally the last intermediate layer 23 and tread 24. After this assembly, the tire is vulcanized in the usual manner.

FIG. 9 is a view of a portion of the carcass of the tire casing with the rubber sleeve removed to see the course and orientation of the cord threads 12 and 14. The cord threads 12 are oriented radially in the short section as indicated by arrows on both sides of the curve B. 14 are only slightly inclined to the longitudinal direction indicated by the curve B. The short thread section 12 'and the short thread section 14' indicate the directions of folding of the thread layers 12, 14 around the steel cable 15.

Claims (6)

OBJECT OF INVENTION A carcass, consisting of two layers or two groups of cord thread layers extending from one bead to the other, the threads in each layer or group of layers being parallel to each other and forming a mesh of quadrilateral meshes, wherein the pairs of opposing sides are oriented in two directions; make a different angle to the circumferential direction, characterized in that the yarns (12) of one layer or group of layers form an circumferential direction (aj) having a greater absolute value than the angle (?) between the yarns (14) of the other layer or group of layers and circumferentially, the greater angle (α) during the yarns (12, 14) varies by greater than the smaller angle (33) and after passing through a maximum value of 90 °, the sign changes and starting from the beads the two angles (α, (3) that are sharp in this area and have the same meaning, at the same time the maximum values on the same circle (B) and the law according to which the two angles (α, β) change is the same on both halves in the exterior view of the tire. 2. The tire of claim 1, wherein at least on a portion of said carcass the ratio is constant and greater than 1. Tire according to Claim 2, characterized in that the ratio (R) is between 1.1 and 10, preferably between 2 and 5. 4. A tire as claimed in any one of claims 1 to 3, characterized in that, in a portion of the carcass at the bead, the angle (/ o) between the sides of the mesh of the mesh or the filling angle (180 ° - χ ₀ ) has a value satisfying the sin (y _o Vr ² —and the sides of the eye extend in the same sense, ie in the same quadrants defined by the circumferential and radial direction of the tire. Fifth pneumatic tire according to claim 4, wherein R ² -1 (x ° = _R 2_j_l J and thus the sum of angles (α _0, β _0), which grip the sides of the mesh to the circumferential direction is smaller than 90 °. 6. Tire according to claim 4 or 5, characterized in that, in the part of the carcass at the top of the tire, the angle (y _s ) between the sides of the eye or its fillings (180 ° - y _s ) has a value satisfying the condition + γ ₀ = 180P; that is, in the portion of the carcass at the apex and at the bead of the tire, the meshes have the same area and the parallel threads have the same mutual distance. Tire according to claim 1, characterized in that the yarns (14) of the second layer form a smaller angle with circumferential direction (/ 3) are more elastic than the yarns (12) of the first layer form a larger angle (a) with circumferential direction. they are separated from them by a thin rubber intermediate layer (13) with a modulus of elasticity of 2 to 5 MPa and a relative elongation of 100%. Tire according to Claims 2 and 6, characterized in that the greater angle (α between the threads (12) of one layer and the circumferential direction is between 24 1 / 2P and 90 °, the smaller angle (/ 3) between the threads (14) of the other and the circumferential direction is in the range of 7 1/2 ° to 18 1/2 ° and the angle (χ) between the sides of the eye is in the range of 32 ° to 148 °. 9. The method of manufacturing a tire according to items 1 to 8, wherein at least two layers of cord threads, which are parallel to each other but intersect with the yarns of the second layer, are stacked on the ready-to-wear drum. about which the folded edges of the layers of cord yarns and the blank bulges, characterized in that the cord threads of two layers laid on the building drum under unequal acute angle (a _o, / 3 ₀ j with respect to the circumferential direction of the tire so that the blank is asymmetrical, and during the swelling, the side steel wires are allowed to rotate freely about the axis of the workpiece, simultaneously with the rotation of the threads forming the meshes. 10. The method according to claim 9, characterized in that the cord yarns laid on the building drum at the angles (a _0, / _J), which have the same meaning and whose sum is less than 90 °. 11. The method of claim 9 or 10, characterized in that the cord yarns laid on the building drum at the angles (a _{0/3 0} j, the ratio of the sines of (R q = sin ₀ sin β ₀ is in the range 2-5, preferably 2.5 to 3.5. 12. Method according to claim 9, characterized in that the cord threads of one layer are laid at an angle of 45 [deg.] And the cord threads of the other layer at an angle of 13 [deg.]. 6 sheets of drawings