FI67054B - DAECK - Google Patents

Description

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Patent and Registration Office ----------- ---------------

Patent · och regfetentyrabMi '* AmMim «d * dod ·« UkiitopJbMoiratf 28.09.8¾ (32) (33) (31) Pwr4 * ty emkiw> nlrd prtortwt 25.08.77

English-England (GB) 35662/77 (71) Dunlop Limited, Dunlop House, Ryder Street, St. James's, London SW1, English-English and (GB) (72) William Lewis Jackson, Sutton Coldfield, West Midlands, England -England (GB) (7¾) Oy Jalo Ant-Wuorinen Ab (5ueen) Tire - Däck (62) Divided by application 782550 - Avdelad frän trap 782550 The present invention relates to a rim-mounted tire comprising at least one circumferential diaphragm area which is retained during use of the tire. by means of a continuous bellows reinforcement which is substantially circumferentially inextensible and non-compressible, a circumferential tread capable of resisting circumferential elongation but capable of bending locally radially inwards, at least one reinforced, tread-connected, load-bearing and load-bearing radially inwardly from the tread, a cavity space below the tread extending around the circumference and a having a width substantially equal to the width of the buffer layer and a radial height substantially less than the cross-sectional height of the ring.

In particular, the invention relates to a tire which meets the comfort, load-bearing and grip requirements normally associated with a pneumatic tire.

In conventional pneumatic tire and wheel combinations where air pressure is used to tension the carcass and when the combination is loaded, the carcass tension progressively decreases near the part of the tire in contact with the ground, providing effective load bearing support by carcass tension in other parts of the tire. Conventional pneumatic tires completely lose their effective load-bearing capacity if the air pressure is lost. Conventional full rubber tires support the load so that the part of the tire that touches the ground is subjected to a compressive load. However, such solid rubber tires become hot, which is why their speed and load-bearing capacity are limited.

It is known that if there is a certain internal prestress on the sides of a pneumatic tire, the effective load-bearing capacity is not completely lost when the tire is compressed. However, previous tires or tire-rim combinations with prestressed sidewalls are associated with various disturbances.

For example, it is known from GB Patent No. 6961 of 1896 to place a steel strip of rectangular cross-section in a cavity between a tire and a wheel rim, the width of the strip being slightly less than the width of the tire tread and several times greater than the circumference length of the tire. Such a strip has an inherent tendency to unwind (and act as a large spring), thereby exerting a radially outward force under the tread of the tire, thereby tensioning the sidewalls of the tire. It is also known to replace the belt (buffer layer) which strengthens the tread of a belt tire with a metal rim which has a width substantially equal to the width of the belt, but which has a larger diameter, also in this case for tensioning the sides. In either case, the use of a solid metal strip, which prevents local compression of the tire in the radial direction, substantially reduces the driving comfort of the tire.

As an alternative solution, a method is known from GB patent publication No. 28233 from 1903, in which the sides are tensioned by moving the ring beads radially inwards. However, this is difficult to implement in practice because the bobbin wire must be cut in order for its diameter to decrease during the radial-inward transition.

It is an object of the present invention to provide a ring which does not have these disadvantages.

The invention comprises a tire characterized in that the on-roll compartment is pressurized to provide prestressing of the reinforcement before the tire and rim combination is installed in the car under load.

If the tire is pneumatic, the prestressing device can preferably tension the tension-resistant reinforcements before the tire and rim are inflated.

A suitable tire and wheel rim combination in which the tire of the invention is used comprises a wheel rim having two axially spaced circumferential bellows and a tire having two load bearing tire walls spaced axially apart to form the sidewalls of the tire, wherein each side is attached at its innermost edge to a diaphragm region held by a respective bellows post and at its outer edge to a corresponding edge of the tread.

The sidewall or both sides of the combination are preferably straight, or at least a substantial portion of their radial length is straight when viewed from the axial cross-section of the ring. The tread is preferably reinforced with a buffer layer extending around the tire like a belt.

The resistance of the reinforced side or reinforced sides to compressive forces is preferably small in the radial direction.

Reinforcement materials with high tensile strength and low elongation are preferably used to reinforce the side or sides so that the tensile forces acting in the reinforcement of its collapsed ground-contacting sector are immediately reduced to close to zero when the combination is subjected to a load.

The stress-resistant reinforcements may be cords or metal wires running in the radial direction or forming an angle with the radial direction. The cords or yarns may form part of a layer or layers of woven or non-woven material, but preferably comprise a substantially radial layer, which is a conventional, substantially non-woven ring cord fabric.

The invention relates to a tire comprising two axially spaced diaphragm regions, two sides and a tread, a buffer layer below the tread, a radially tubular cavity below the buffer layer extending circumferentially around the ring and having a width equal to that of the head. the width of the tread and having a radial height substantially less than the height of the tire, and a substantially rigid rim located in the radially inner wall of the tubular cavity having an axial width equal to the axial width of the cavity and the cavity pressurized by the fluid so that radial and outward and which allows the sides to be pre-tensioned.

The sidewalls are preferably reinforced with radial reinforcement cords that are uniform from one diaphragm area to another, with these cords passing over the buffer layer over the tread area of the tire carcass.

The cavity can be filled with air or liquid and it is most convenient to pressurize only the cavity inside the tread area and not the main cavity of the tire, which would be close to the outside air pressure.

The rigid rim can be provided in both different ways; for example, it may be a simple steel rim or it may be formed from a thicker rim of a softer material, which may be reinforced by conventional means corresponding to conventional tire buffer layers. By appropriately selecting the material and structure, the natural frequency of the rim 5 67054 can be changed to provide harmonic damping so that the tire can be adapted to the intended use of different vehicles.

The present invention the cavity according to the aspect is at its most effective a substantially flat tube between the buffer layer and the rim and the main purpose is to provide a stiffened ring for each edge of the tread area and thus one for each side.

The curvature of the edges of the cavity can be reversed so that the fluid pressure in the cavity tends to straighten the edges. This effect further increases the stiffening forces that affect the edges of the tread.

An alternative support for the edges of the tread comprises a tube of circular cross-section located radially below a substantially transversely rigid bumper layer with a reinforcement wrapped around the tube having a large pitch angle so that filling the tube with air causes its main radius to increase without substantially altering the circumference. , wherein the reinforced tube exerts a radially outward stabilizing force on the central part of the buffer layer and the transverse stiffness of the buffer layer thus forms the desired support in the edge region.

Also in this case, it is sufficient that only the tube is pressurized, so that there is no equal pressure in the main cavity of the ring. Pressurized gas or liquids can be used to radially expand the tube.

The length of the tube can be several times greater than the length of the tread and is helically wound to extend below the entire inner surface of the tread in both the longitudinal and transverse directions.

Some embodiments of the present invention will now be described, by way of example only, with reference to the accompanying schematic drawing, in which:

Fig. 1 is a cross-sectional view of a tire according to the present invention showing details of the tread area and carcass when a radial outward force is applied to the buffer layer of the tire; Fig. 2 shows a detailed modification of the structure according to Fig. 1; Fig. 3 is an alternative structure to Fig. 1 for stiffening the tread area; Figure 4 shows an alternative ring structure according to the present invention; Figure 5 shows the structural form r of a whole rubber tire according to the present invention.

Figure 1 shows a ring with a relatively rigid rim 60, which may be, for example, a flat steel strip shaped as a rim and cast into the inner wall 61 of the tubular cavity 62. The width of the cavity 62 is equal to the width of the tire tread 63 and the radial direction of the cavity 62 the outermost wall has a buffer layer 64. The buffer layer 64 is in principle a conventional tire buffer layer, but is further stiffened considerably in the transverse direction, for example by means of an additional reinforcement layer perpendicular to the circumferential direction. In other respects, the tire comprises straight sides 65, diaphragm areas 66, and a belt-reinforced carcass P, in which the cord layers pass from bead to bead and pass through the tire tread area above the buffer layer 64, as shown in the drawing.

One feature of this system is that the edge areas of the cavity, due to the relatively small cross-sectional radius, do not bulge outwards and therefore prevent any lateral pressure from affecting the sides. These can therefore remain straight, as required by the invention, only under the effect of radial stress.

The annular main cavity 67 of the ring is not filled with medium, but only a thin and flat annular cavity 62.

It can be seen that in this example, the radial prestress FQ of the side causes a compressible circumferential stress T70 in the buffer layer, whereby

i = “2 F

R o T * buffer layer tension R s buffer layer radius

Fq = lateral stress / circumferential unit

If the compressive strength of the buffer layer is large enough, this force balance is stable and the ring can operate in this state. However, if the cavity 52 is filled, there is 1 - pw - 2Fo where P s overpressure in the cavity, and W = width and compressive stress (T neg.) Decreases or even changes to tensile stress (T pos.).

The support of the buffer layer is provided by pressure and the edges are supported to provide support rims for the sides.

This example is very effective in the sense that the pneumatic stiffness at a given pressure can be up to twice that of a more conventional tire, so that the load capacity of the tire is much higher.

In Figure 1, the tubular cavity and the rim are integral with the tread area of the tire. This is not essential, although it reduces relative movement and friction. In some cases, it may be advantageous to reinforce at least the edges of the tube, for example by means of cords wound at an angle of almost 90 ° to the circumferential direction. The radial thickness of the tube cavity should be at least equal to the normal compression in use so that the inner rigid rim does not normally squeeze in. The rim itself should be relatively rigid to support the compressive stresses generated by the air pressure (which should not be supported on the sides of the pipe by 8 67054). A steel rim is appropriate, but it is preferable to use a thicker rim of a softer material that can withstand any momentary large depression. The weight range of the rim is very wide. For this reason, it is possible to adjust its vibration frequency independently and independently of the vibration of the tire, which makes it possible to develop a harmonic attenuator for certain ring vibration frequencies. For this reason, it is possible to "tune" the tire for better driving comfort.

Figure 2 shows a ring of a similar type in which the edges E of the flat tube 62 are not reinforced but thickened and curved in opposite directions.

These edges form "vaults" and can maintain air pressure. The thrust of the vaults provides additional support at the edges of the buffer layer 64 where the carcass tension tends to pull them inward. This keeps the buffer layer "flat" and equalizes the contact pressure distribution.

Fig. 3 shows another embodiment in which the buffer layer 64 is supported by a tube T on which reinforcement cords are helically wound, which form a large angle against the circumferential direction so that the filling pressure causes an increase in the main radius without any substantial change in the cross-sectional area.

For a 90 ° reinforcement, the equilibrium shape is almost circular, while when the angle is smaller, it is in the shape of a flat ellipse that presses against the width of the inner surface of the belt over a larger area.

Alternatively, a plurality of smaller tube coils may be used to cover the inner surface of the belt more evenly, or a longer tube arranged in a plurality of coils extending across the width of the tread.

Figure 4 shows a variant of the invention in which the tire can perform part of the operation of the wheel and in which the combination withstands very large depressions without transferring excessive impact loads to the suspension.

The tubes 70 are attached to the ring 71 by cords 72 and 96704. The ring can be rotated about a suitable axis. Pipe 70 can be reinforced in the same manner as in the previous example. When filled with medium, it tends to expand in the circumferential direction but the cords 72 retain this and tension under the effect of the filling pressure.

Although this example does not comprise any buffer layer, it is apparent that the pressurized tube forms a support for the straight cords of the flanks. One rim thus supports each side.

Tires of this type can be prestressed by moving the bellows axially outward. Such displacement can lead to greater transverse stability while reducing buffer stress and driving comfort.

The cords can be protected by a tread layer 74 of rubber compound, which may or may not extend to the diaphragm areas 71. If the cords are left bare, they need not be conventional ring homes but may be, for example, nylon monofilaments of arbitrary cross-sectional shape, or they may be stainless steel wires. The ring of this construction is accessed through the inter-cord areas and can be utilized to facilitate the installation of components between the bellows to develop side bias tension.

To improve the resistance of this tire system to transverse tensioning moments, for example, elastomeric fillers 75 may be used, which may include reinforcements between the tube 70 and the cord 72, as shown, or a reinforced buffer layer near the bottom of the tread, either inside or outside the carcass.

Figure 5 shows a half cross-section of a generally rectangular elastomeric rim 88 vulcanized in contact with the buffer layer 86 and including a cavity 87. After vulcanization, it is wrapped in a rubberized ring cord fabric or the like with a continuous helix C and then shielded from 10 654 with a layer 89 of substance. After being placed on the wheel rim 90, the continuous annular cavity 87 is filled with a curable liquid. This expands the interior of the "ring" and fills the cavity of the wheel rim, tightening the cords that tend to pull the bumper layer inward and compress the material 85 outwardly against it.As the tension 2F0 has a radial component that is eliminated when the tire is compressed, this type of tire / indentation equation L * (A + Ct), where L s supported load A - effective stiffness of the structure C = constant t = side prestress ds tire compression

Material is cut away from the sides 91 of the rim 88 of elastomeric material to allow the cords to loosen when the ring is compressed. Without this concavity, there is a risk that the bulge during rubber compression will increase the tension 2FQ or at least prevent it from decreasing. The efficiency of these rings is based on providing the greatest possible reduction in prestressing when the tire is compressed and therefore concavities are an advantage.

For all the tires shown, a large sidewall prestress tends to pull the bumper layer inward at one or two points across its width, while the support mechanism compresses outward over its entire width. These forces tend to bend the cross-section of the buffer layer.

Since the buffer layer is a support rim, this bending implies circumferential stretches and compressions in addition to the stresses caused by its bending in and out of the contact area.

It is preferred to minimize transverse deflection by increasing transverse stiffness.

Claims (7)

A rim mounting tire comprising at least one peripheral bead region, which, during use of the tire, is retained on the rim bead seat by a continuous bead reinforcement which is substantially circumferentially expandable and uncompressible, a peripherally expandable ( 63, 74, 89), which adversely counteracts peripheral expansion, but is locally flexibly radially inert, at least one having a reinforcement (P) provided with the load-bearing wall (65) which extends radially inward from the tread, a cavity (62, 70, 87) located below the tread, the cavity extending circumferentially and the width of which is substantially equal to the width and radial height of the protection structure substantially less than the cross-sectional height of the tire, characterized in that the cavity (62, 70, 87) is air-filled so that it achieves a bias in the gain (P) before the tire and rim combination have been mounted on a vehicle and loaded. Tire according to claim 1, characterized in that the load-bearing wall or at least one