DE1912598A1 - tire - Google Patents

Description

PATENT LAWYERS λ λ UM _n

CR. MÖLLER-BURE. DIPL.-INQ. GRALFS η 1013

DR. MANITZ · DR. DEUFEL

6 MUNICH 22. ROBERT-KOCH-eTR. I.

TELEPHONE 225110

THE SUHIOP COHPAIT LIMITED Dunlop House, Ryder Street St. James's, London S.V.1.

England "Tire"

Priority: Japan, tob 13. HBrs 1968

Mr. SHO. * 3-O16 * 38

The invention is seen on pneumatic tires.

In conventional tires, the middle part of the tire tread _t expands when the pressure in the tire is increased and thus the curvature of the tread decreases across the tread su, which in turn reduces the width of the ground contact area at higher pressures. This is due to the fact that the inner surface of the tire approaches more the circular 9e-Etalt with lower pressures. In order to obtain maximum ground contact area su, it is seen as desirable * to make the running surface as flat as ~ ^y glioh su; for this reason the shoulder parts of the tire are built to have a greater thickness than the center of the tread. The extra thickness on the shoulders, however, leads to the generation of heat if and when the tire sags during operation

909849/0812

the heat generation becomes excessive, the tire is quickly damaged.

One way to avoid this difficulty is to use the "low profile tire", which is relative to the radial dimension builds low, but is wide across the tread; even here, however, the curvature of the running surface is still considerable Dimensions depending on the tire pressure, the tread contact area is reduced at higher pressures.

Another earlier suggestion is using a belt made of a non-stretchable or non-stretchable outer fabric worked, which is provided over the circumference of the tire; the tire carcass (the fabric sub-structure) then becomes vulcanized in a shaping shape that closely approximates the shape of the tire after it has been correctly inflated assumes, however, such tires are unusual in terms of their production method and thus expensive. Beyond that, aeigen such tires different, γοη certain points of view undesirable Properties such as reduced fatigue strength and sidewall durability, relatively high static steering torque, and impaired "Pahr" feel, though the high-speed stability improves etin can

According to a better, more effective solution should now be found for the said difficulty can be found.

According to the invention, the inner surface of a pneumatic tire is used designed so that as the air pressure is increased, the tread curvature decreases.

The pneumatic tire according to the invention can be manufactured so that a desired flat tread profile results, however, it is also possible to ensure that the

909849/0832

Curvature decreases to below zero, so that it really is results in a flat or straight profile and that it is an inverse one Preserves curvature so that the profile becomes concave instead of convex.

A known tire eats in its interior so constructed that it forms the sidewall arcs of a large radius has under the tread, which merge into arcs of small radius at the shoulders. The design for the invention It can be used with large radius arcs extending over the shoulder and in the middle the tread converge in an arc of a small radius *

Preferably, the shoulders each include a circumferential ring of low bias material to generate heat and a high resilience or high elasticity, so that the possibility of compensation greater expansion in the shoulders than in the tread center portion after the tire is pressurized will.

An example embodiment of the invention will now be based on of the accompanying drawings are explained in more detail », in those

Figure 1 shows an axial section through a tire according to the invention;

FIG. 2 is an Axialsohnitt solely through the tread part of the tire in Figure 1, while this on a not shown Tire molding device is assembled f

Figure 3 shows the same tire before filling (solid lines) and after filling (dashed lines) ι

FIG. 4 is a representation similar to FIG. 3, but shows

909849 / 08-12

a common tire for comparison.

According to the drawings, in particular in Figures 1 and 2 »consists the tire of a carcass 7 made for example by any known method and a tread reinforcing fabric or, a Zwiechenbau 3 »" for example a cord which is placed over the crown or head of the carcass, i.e. over the entire width of the tread area

A shoulder base strip 1 is arranged so that each lateral Edge of the fabric 3 is covered and each strip 1 = forms a complete ring that runs around the tire * The cross-sectional area of the strip 1 is sufficient for that Tread material 2 has a relatively constant thickness over the Width of the running surface and the desired shape evokes. As shown, the strips 1 are essentially triangular in cross-section, but this is the case not essential. The vertex of the triangle is located below the side edge of the tread.

The base strips are covered by tread rubber 2 and at the same time the planks 5 of the tread and the flanks 6 of the side walls are formed by conventional methods. If desired, the strips 1 with hooks 5 and 6 be preformed.

If the fabric 3 consists of metallic Liezenoord, so can the strips 1 to be arranged under the fabric * whereby that Tissue becomes relatively flat.

The base strips are made of a material »which has low heat generation ability, but must have affinity

909849 / 081-2

2um tread material for reasons known to those skilled in the art to have. Rubbers that are suitable as base strips »um- ' For example, contain polybutadiene, styrene-butadiene polymers, which are produced by solution polymerization and AIfinkaut schuk (synthetic, made of polybutadiene with a high content of trans isomers and susceptors, usually 1.5 # of 1.4 «bihydronaphthalene) alone or in combination with other chewing cards; however, the invention is not limited to such rubbers ".

After vulcanization in a mold, the finished tire has the cross section shown in Figure 1. Both ends of the small radius arc 10 on the inner surface of the tire, which is below the middle of the width of the flow area, go gradually in arc larger radius or in substantially rectilinear parts 15, which calibrate against the sidewalls of the tire extend. So the radial thickness at the shoulders is the same the sum of the tread thickness on the shoulder tokens 4 - 6 can be a common thickness - plus the Β * β1 · ~ rings 1, gord fabric and carcass; this is or can be substantially larger than a normal tire at these points be"

During the fall, the inner surface of the tire is against you expands towards the full circle and thus the expansion under the shoulders is greater than at the top of the head, as through indicated by the dashed line in FIG. This in turn leads to the fact that * reduces the curvature of the tread to zero is reached or Hull is reached or goes beyond zero »

The tire can be manufactured by an ordinary method be and be vulcanized in usual shapes of normal shape »

'909849/0912'

For comparison, FIG. 4 shows a conventional tire in which it is readily apparent that the tire gradually adapts to the shape shown in broken lines when it is filled, the curvature of the tread increases.

Claims

909849/08 * 12

Claims (8)

- 7 - D 1013 PATENT CLAIMS ( 1,)) Pneumatic tire, characterized in that its inner surface is designed in such a way that the tread profile curvature decreases with increasing air pressure. 2.) Tire according to claim 1, characterized in that
the tread profile at normal inflation or inflation pressure
is flat. 3.) Tire according to claim 1, characterized in that
the tread curvature is reversely curved at normal inflation or JUI pressure. 4.) Tire according to one of claims 1 to 3, characterized in that the inner surface of the tire has a rope keeled radius below the center of the tread as well as parts of large radius or straight shape which extend in cross-sectional profile over the shoulders. 5.) Tire according to one of the preceding claims, characterized characterized in that a base ring is built into the tire construction and wraps around the tire within the shoulder portion extends, with the requirement aring from low the material. is composed » 6.) Tire according to claim 5 »characterized in that
a layer of tread reinforcement fabric or outer fabric
extends laterally below each pair of base rings. 90984 9 / 08-12 7.) Tire according to claim 5t daduroh characterized in that a layer of woven tread reinforcement or an outer fabric extends laterally above each ball ring a pair of ball rings. 8.) Pneumatic tires, essentially as described in tuxd in Figures 1 ″ to 3 shown. X-X-X-X-X 909849 / 0.812 Empty soap