FI61841C - KOMBINATION AV DAECK OCH HJULFAELG - Google Patents

Description

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C (45) Patent granted 11 10 1932 yjja Patent meddelat ^ ^ (51) Kv.ik? /Int.ci.3 B 60 C 3/00 FINLAND — FIN LAND (21) P * tMittlhak «mu · - PKancanaBknlnf 752375 ( 22) Hakamltpllvl - AiwBluilngadag 22.08.7 5 (23) Home - GIM (h «tsd« g 22.08.75 (41) Tullut | external - Blhrlt affwitllf 2k. _

Patent · och registerstyrelsan Ameku utUgd och utUkriftM pubiic * rad 30.06.82

(32) (33) (31) * nr *** r · ~ ο) ^ .- β ·, ι «ι priority 23.08.7U

England-England (GB) 37159/7 * + (71) Dunlop Limited, Dunlop House, Ryder Street, St. James's, London SW1,

England-England (GB) (72) William Lewis Jackson, Sutton Coldfield, West Midlands, England-England (GB) (7 * 0 Oy Jalo Ant-Wuorinen At »(5 * +) Tire and wheel rim combination - Kombination av däck This invention relates to a tire and wheel rim combination which is particularly intended for use without pneumatic pressure in a tire.

According to the present invention, a tire and wheel combination comprises a tire having a tread and two sidewalls with a substantially straight cross-sectional center terminating in bead members implanted on the wheel rim, the sides extending axially and radially inwardly from the tread edges toward the bead portions. the whole is substantially triangular in cross-section, the tread being reinforced substantially over its entire width by a reinforcement layer or belt which is substantially inextensible so that the tread becomes substantially laterally inextensible and a rigid wheel rim with two seats for tire beads.

The tire and wheel combination according to the invention is characterized in that the tire reinforcement layer is straight or concave, while the tread 61841 2 outside the reinforcement layer is thicker in the center of the tread than at its edges so that contact with the substrate causes the reinforcement layer and tread edges to retract. that the thickness / length ratio of the sides is large enough to maintain the straight shape of the centerline when the sides are compressed in their longitudinal direction, and that the position of the ribs on the rim is adjusted so that the sides are longitudinally compressed when the tire is mounted on the rim.

It is obvious that in order for the body of elastomeric material to remain straight during compression, the thickness must be greater than a certain minimum thickness with respect to its length, otherwise the body will have a more stable elastic state in a curved shape and assume this curved shape when subjected to the smallest lateral force.

In a simple rectangular body, this ratio is about 1 to 31/2, but the actual value depends on the shape and material of the body. Suffice it to say that the ratio for a particular shaped body can be determined by a simple experiment.

The tire is in principle a non-pneumatic tire, which has certain advantages, in particular the advantage that it does not suddenly collapse in the event of a tire failure. However, in some cases, the pressure in the tire may improve its performance, provided that the structure of the tire and the magnitude of the pressure are such that the pressure does not remove the rubber pressure on the sidewalls.

The tread of the tire is preferably reinforced by a belt comprising a plurality of layers of substantially inextensible cords, for example steel or rayon. It is possible to use a wide variety of belt structures, so that different structures have special advantages in certain applications. For example, the belt may comprise two layers of steel cords with equal and opposite diagonal angles of 10 to 80 °. Alternatively, the belt may comprise three layers, one with a diagonal angle of 90 ° and the other with equal and opposite diagonal angles of 10 to 45 °. The belt extends in the axial direction at least up to the center lines of the ribs at the joints between the ribs and the tread and preferably across them. The centerline of the flank is the line halfway between the outer and inner surfaces of the flank when inspecting the cross-sectional area.

In most cases, it is also necessary to provide the edges of the belt with additional reinforcement to limit the radial component of the forces caused by the compression of the sides. These may be folded edges at the edges of the belt or narrow additional diagonal strips of cord fabric or parallel turns to 0 °.

It is obvious that although the structure of the belt is similar to that of the well-known radial ring belt, there are differences in their mode of operation. First, the pre-pressed sides of this ring require additional reinforcement at the edges, and second, the large transverse component of the force requires that the transverse modulus of the belt be greater than usual. This in turn results in the use of larger diagonal angles in the belt layers or the use of 90 ° layers.

The tread of the tire is axially wider than the rest of the tire, and when inspecting the cross-sectional area, the sidewalls preferably extend from the rim of the wheel to a tread of 25 to 70 °, most preferably at an angle of 40 to 50 ° with respect to the axis of rotation.

The sides may be entirely rubber and are preferably rubber that is harder than tread rubber; preferably they do not contain conventional types of beads with an unstretchable reinforcement core. The amount of sidewall compression when the tire is mounted on the wheel rim is preferably 5 to 20% of the original linear length of the sidewall.

Each passage preferably has an area with a lower stiffness, i.e. thinner than the rest of the sidewall located either near the edge of the tread reinforcement or near the rim of the wheel, but preferably having two such areas, one at each of said points.

The invention will now be described in more detail, by way of example, with reference to the accompanying drawing, in which Fig. 1 shows a simplified schematic cross-section of a ring according to the present invention; Fig. 2 is a graph showing the stresses generated at the sidewalls of the tire of Fig. 1 due to pre-compression; Fig. 3a is a view similar to Fig. 1, but showing a tire having a thinner tread in the center than at the edges; Fig. 3b is a graph showing the behavior of the tire of Fig. 3a under load; Fig. 4a shows a simplified schematic cross-sectional view of a ring with additional internal "sides"; Fig. 4b is a graph showing the behavior of the tire of Fig. 4a under load; Fig. 5 is a simplified schematic cross-sectional view of a ring having thinned areas on the sides; Figures 6-8a show various possible cross-sectional forms of the sidewalls of the ring of Figure 5; Fig. 8b is a graph showing a modified tire of the type of tire of Fig. 5 having a circumferential retaining ring at the edge of the tread reinforcement; Figure 9 shows a cross-section of a tire according to the invention when mounted on a wheel rim.

Figure 1 shows a simplified schematic view of a cross section of a tire assumed to be mounted on a rim. A is a cross-section of the tread reinforced by a substantially inextensible belt running around the circumference of the tire. BID | and B2C2 show the positions of the sides when mounted on the rim, while B1D1 and BgD ^ show the positions before mounting. Since B ^ D ^ and BgD ,, are longer than B ^ D ^ and B ^ C ^ *, the shortening of the side from D to C causes the side to be compressed during mounting on the rim (or wheel).

It is obvious that the transverse movement D-C is only one way to shorten the sides and that there are other ways that also cause the side to pre-compress. Thus, the radial, transverse or combined radial and transverse movement of the inner edge of the sides compresses the side in size. Transverse movement is most suitable because it is mechanically simple. Other alternatives exist if the outer edge of the flank is moved radially or transversely inwardly, for example by making and pre-vulcanizing separate oversized flanks, which are then forcibly attached to the inside of the pre-vulcanized belt.

Thus, in the ring according to the present invention, the side tension is provided by pre-compressing the sides mechanically without air pressure. Thus, the air pressure in the tire can be significantly reduced compared to conventional pneumatic tires or it can be completely eliminated. The risk of the tire exploding can therefore be completely eliminated.

Figure 2 shows the stresses P exerted by the pre-compressed side on the inner edge of the rim and on the other edge of the reinforced tread A; is not exactly equal to or in the opposite direction because it acts along the outer circumference, which is longer than the inner circumference. F 1 can be divided into two components, which act radially outwards and are limited by the circumferential stress of the tread reinforcement and act transversely outwards and are limited by the transverse stress acting across the tread reinforcement.

This tension can be made to work usefully. As described so far, a tire without internal air pressure in contact with a flat surface should support the entire load from the two contact edges. A more even contact is achieved, if necessary, by using a tread layer E which is thicker in the middle than at the edges, as shown in Fig. 5a. Figure 3b schematically shows how it deforms upon contact with a flat surface. and the cross-sectional shape of the tensioned belt in between becomes convex outwards, enabling it to support the test pressure P. If the resulting radius is R, the contact pressure is determined according to the well-known equilibrium equation of general shape 6 61 84 1

p .JL

R

The detailed selection of the tread thickness profile and thus the radius R depends on the application in question and is determined in a known manner.

The ability of the central portion of the cross-sectional surface to support the load can be further enhanced by using a pre-compressed inner liner, as described in Patent Application No. 750,498.

It can also be increased by using air pressure inside the tire, although the pressure should not be so high that its loss would cause dangerously detectable loss of driving characteristics of the tire. There are other limitations with respect to the amount of pressure used, as explained below.

One method that can be used to provide a contact pressure more evenly distributed over the width of the tire requires the use of additional internal "sides" or supports, as shown in Figure 4a, wherein the tire comprises a reinforced tread G with a double hump-shaped cross-section. side "H, J, E and M. In this case, it is necessary to further modify the thickness of the tread to obtain the result shown in Fig. 4b when the tire is in contact with the ground.

It can be seen from Figure 3b that the sides bend outwards when the ring is compressed. Such bending causes the outer surface to stretch. This stretch is undesirable for two reasons. First, if it exceeds the pre-compression support of the substance, it can cause an increasing number of fatigue cracks. Second, the rotation of the tire under load causes periodic variations in tension as each point of the tire passes the contact area; the hysteresis of the material would generate heat and since the sides are necessarily thick, this would cause too high temperatures.

To minimize these effects, it is preferred to change the shape of the sidewall to facilitate the necessary bending by using a "hinge" area, which should be thinner as shown in the tire of Figure 5, comprising a reinforced tread portion N and two sidewalls 0 and P, each thinned, i.e. hinge "area T. This rib shape has three advantages. The extensibility of the surface decreases, the pre-compression increases locally and the reduced thickness facilitates the removal of heat.

7 61841

Similar findings may apply to the innermost edge of the flank and clearly the material on the shoulders of the hinge "S" has little use and it is therefore reasonable to pay attention to a flank Z with a rounded cross-sectional shape and two thinned areas T ^ T2, as in Figure 6. has been presented. Very many forms of this type are possible.

Tire pressure is limited by another factor. No pressure applied shall be so great as to cause the ribs to bend so large as to cause bulging. Any pressure applied to the tire forces the sidewalls outward and thus tends to curve the sideways outwardly. This is allowed except for two restrictions.

1. The curvature must not cause the side to pivot.

2. The curvature must not cause any part of the side to stretch to such an extent that the pre-compression is lost.

The joint between the side and the reinforced tread portion can be reinforced by increasing the area of the joint. The side U shown in Fig. 7, which has a flange W on the radial outer edge, is an example of this. This causes the centerline of the side section to be distorted from its extreme end, but since the thickness of the side at the flange is very much greater than at other points on the side, a small distortion of the centerline is functionally insignificant.

The performance of this joint can also be improved by using a tread reinforcement X with a smaller diameter at the rheumatism, as shown in Figure 8a. In the ring of Fig. 8b, this shape has been further modified to use a circumferential reinforcement cord rim Y around the edge of the reinforcement belt. The purpose of these cords Y is to ensure that the pre-compression of the sides does not reduce the increase in the edge of the tread reinforcement, i. elongation, due to centrifugal forces such as rapid driving.

All the schematic drawings described above show sides with a section center line (dotted line) at an angle of 45 ° to the axis of rotation. 45 ° + 5 not the most appropriate direction for reasons related to the severity of lateral flexibility. However, since special rings may require structures with different angles, it is possible to change the angle within a wide range without departing from the basic idea of the invention.

61841 8

The ring shown in Fig. 9 comprises a tread portion 1 reinforced with an annular belt assembly 2 and two sides 3 and 4.

The belt assembly comprises three layers 3 «6 and 7« of which the diagonal angles of the layers 5 and 6 are equal and opposite and of 15 ° to 30 ° and the diagonal angle of the layer 7 is 90 ° with respect to the circumferential plane of the tire. The cords of layers 3, 6 and 7 are steel cords, although they may be some other material of good strength, such as the recently available aromatic polyamide cord. At the edges of the belt assembly, several turns of steel cord 7a with a diagonal angle of 0 ° are arranged on the layer 7.

The sides 3 and 4 are straight and made entirely of rubber and have a thickness / length ratio of 3.33: 1 at their radially innermost ends and 3 * 1 '1 at the outermost ends, and the sides are slightly tapered in the cross-sectional direction.

The manufacture of a tire is a relatively simple operation, in which the belt structure is initially assembled from its associated layers in a conventional manner and, if desired, partially vulcanized to improve its stability. The belt is then placed on a solid core divided into segmental paths and placed in a transfer or injection nozzle. The unvulcanized rubber mixture is then fed into a mold to form the rest of the tread and sides, and finally the tire is vulcanized. The mold is opened and the ring is removed, after which the segmented core is removed from the ring.

The ring is placed on a wheel rim comprising two annular plate members 8 and 9 and a central portion 10. The circumference of each annular plate is provided with a bead seat comprising two surfaces, one of which is an axially outwardly facing surface on the inside of the bead portion of the side. in the plane, and another radially outwardly directed surface.

The plate members 8 and 9 are fastened to each other by a plurality of nuts and bolts 11 and have spacers 12 interposed between the plates. The second plate member 8 also has a plurality of threaded holes into which nooel screws 13 can be inserted to force the plate members apart.

To mount the ring on the rim, both plate members are initially placed in the ring, with the bolts 11 being loosely in place to position the holes in the plate members opposite. The bead sections of the sidewalls of the ring are placed on the ball joints and plate members

Claims (8)

9 61841 are forced apart to compress the sidewalls of the tire by means of the lifting screws 13. The bolts 11 can then be removed and the spacers 12 in place, after which the lifting screws are removed and the plate members are firmly fastened to each other with the bolts 11 against the spacers. The central part 10 of the wheel is placed in place when it is desired to attach the wheel to the vehicle and the bolt holes 14 are for this purpose. Wheels and tires of this construction have been fabricated and tested and have been found to support satisfactorily considerable loads without tire pressure because the compressive force on the sidewalls holds the tire in place on the wheel. However, it is recommended to provide the wheel with a short flange that extends axially outward from the bellows chuck to prevent the road from penetrating between the tire and the wheel and to further reduce the chances of the sidewall bellows moving away from the seat. A tire and wheel combination, in particular for use without pneumatic pressure in a tire, comprising a) a tire having a tread (1) and two sidewalls (3, 4) having a substantially straight cross-sectional center and terminating in beads to be implanted to the rim of the wheel, the sides extending axially and radially inwards from the edges of the tread (1) towards the bead sections so that the tire as a whole is substantially triangular in cross-section, the tread being reinforced over its entire width by a reinforcing layer or belt (2) is substantially inextensible so that the tread becomes substantially laterally inextensible, and b) a rigid wheel rim (8, 9, 10) with two seats for the tire beads, characterized in that the tire reinforcement layer is straight or concave, while the tread material outside the reinforcement layer is thicker in the middle of the tread (1) than its at the edges so that contact with the substrate causes the reinforcement layer and the edges of the tread to pull towards each other so that the thickness / length ratio of the sides (3, 4) is large enough to maintain the straight shape of the centerline when the sides (3, 4) are compressed longitudinally, and that the position of the beads on the rim (8, 9) is adjusted so that the sides are under longitudinal compression when the ring is mounted on the rim. Combination according to Claim 1, characterized in that the reinforcement layer comprises two layers (5, 6) of steel cords with equal and opposite diagonal angles of 10 to 80 °. Combination according to Claim 2, characterized in that the reinforcement layer comprises three layers (5, 6, 7), one (7) of which has a diagonal angle of 90 ° and the other layers have equal and opposite diagonal angles of 10 to 45 °. Combination according to one of the preceding claims 1 to 3, characterized in that each side is provided with a region (T) with a lower stiffness, either at the edge of the tread reinforcement or near the wheel rim. Combination according to one of the preceding claims 1 to 4, characterized in that the compression of the sidewalls when the tire is mounted on the rim of the wheel is 5 to 20% of the original linear length of the sidewalls. A combination according to claim 4, characterized in that each side has two such lower stiffness areas (T1, T2), at each point. 1. The drive unit, which is connected to the air after a pneumatic operation, has the following conditions: in the case of headings, colors and axles of the axles and of the radioactive head (1) of the headform part, which may not be used in the light of the three-dimensional shape of the parts, the colors of which may be (a) a cross-section of the main body of the head (2, 9, 10) and a cross-section of the main body (8, 9, 10) of the head (8, 9, 10);