WO2006122598A1

WO2006122598A1 - Pneumatic vehicle tyre and method for producing it

Info

Publication number: WO2006122598A1
Application number: PCT/EP2006/002256
Authority: WO
Inventors: Silvia Kaiser; Torsten Ideker; Alexander Höfer
Original assignee: Continental Aktiengesellschaft
Priority date: 2005-05-18
Filing date: 2006-03-11
Publication date: 2006-11-23
Also published as: EP1883546A1; DE102005022695A1

Abstract

Pneumatic vehicle tyre of a radial type comprising a profiled tread rubber (1), a multiply belt assembly (2), an inner layer (4), a carcass (3) of at least one ply, which is taken around bead cores (6) in bead regions, sidewalls (8) and, incorporated in the region of each sidewall (8), at least one cross-sectionally crescent-shaped reinforcing profile (9) respectively extending at least over a large part of the length of the sidewall and consisting of elastomeric materials of different hardnesses. The vehicle tyre is distinguished by the fact that the reinforcing profile comprises three radial part-cores and an axially outer rubber layer, a radially upper part-core and a radially lower part-core respectively consisting of a hard elastomeric material, and a radially central part-core, arranged between the upper and lower part-cores, consisting of a soft elastomeric material.

Description

description

VEHICLE TIRES AND METHOD FOR THE PRODUCTION THEREOF

The invention relates to a radial pneumatic vehicle tire with a profiled tread, a multi-layer belt, an inner layer, an at least one carcass, which is guided around bead cores in bead areas, side walls and at least one each in the region of each side wall introduced, in cross-section crescent-shaped reinforcing profile , which in each case at least a majority of the

Sidewall length and consists of elastomeric materials of different hardnesses.

Such in the case of breakdown self-supporting pneumatic vehicle tires have been known in different versions for some time. The reinforcing profiles installed in the region of the sidewalls of the tire are designed with respect to their cross-sectional shape and with regard to various properties of their elastomeric mixture such that they are able to withstand the tire in the event of a sudden pressure drop, ie in the event of a breakdown, for a certain time or over a certain amount To obtain mileage self-supporting, so that a further journey is possible. A self-supporting tire of the type mentioned is known for example from DE 29 43 654 A1. The tire is provided in the region of its side walls in each case with a mono- or multi-part, approximately crescent-shaped reinforcing profile, which is arranged between the inner layer and the carcass ply and extends below the belt and into the vicinity of the bead areas. From WO 01/43995 A1 a self-supporting tire is known, in which each side wall is provided with a reinforcing profile, which over its cross section of layers of a more flexible material and a stiffer material consists. Each reinforcing profile is therefore composed of a plurality of layers oriented substantially in the tire transverse direction. US Pat. No. 4,287,924 shows an embodiment of a self-supporting tire in which two crescent-shaped reinforcing profiles are provided per side wall, each interposed between the inner layer and the carcass ply, with the reinforcing profile following the carcass ply consisting of a more flexible, softer elastomeric material as that which adjoins this and the inner layer of the tire. Other embodiments of a self-supporting tire are shown in U.S. Patent 5,526,862. Here, the reinforcing profile inserted in the region of each side wall between the airtight inner layer and the carcass covers on one side an elastomeric core introduced in the region of the thickest point of the reinforcing profile, the other side of which adjoins the inner layer of the tire. The modulus of elasticity of the elastomeric material of the reinforcing profile is lower than that of the core. Thus, it should be possible to make the reinforcing profile of a relatively soft material to improve the ride comfort of the tire under normal driving conditions.

From EP 0542 252 B1 a generic tire is known whose reinforcing profile consists of three sub-cores, wherein an axially inner sub-core, which is arranged in the bending region, consists of a relation to the other part cores harder material. According to the teaching of EP 0542 252 B1, that sub-core is intended to absorb the highest voltages and to lengthen mobile distance in run-flat conditions.

Reinforcement profiles or parts of reinforcing profiles, which consist of a rather hard compound, are required to ensure the self-bearing ability of the tire in the run-flat and are therefore carried out correspondingly solid and stiff in the known constructions. This leads to increased vibrations during normal driving conditions, since excitations of the ground contact area are transmitted more or less directly to the chassis, whereby the latter is loaded. Furthermore, the ride comfort of such tires is perceived as low, in particular by vibrations and vibrations. The invention is therefore based on the object to remedy this situation and to design a vehicle tire of the type mentioned, which reduces or dampens vibrations and which at the same time has at least the same properties in run-flat, as previously known vehicle mature.

This object is achieved according to the invention in that the reinforcing profile consists of at least three radial split cores and an axially outer rubber layer, wherein a radially upper split core and a radially lower split core each consist of a hard elastomeric material, and one between the upper and lower split cores arranged radially middle part of core consists of a soft elastomeric material.

Reinforcing profiles designed according to the invention therefore have a hard core which has a soft part core approximately in the radial center, which represents the kink point in run-flat running, which acts similarly to a compression rubber or behaves like a vibration damper. The reinforcing profile thus receives resilient properties; Excitations of the ground contact surface are not given directly to the chassis, but are already caught in the tire and damped. The ride comfort can be through this

Significantly improve the measure. Furthermore, the reinforcing profile or its soft mixture can absorb the compression stresses occurring under load in the event of a breakdown in the hard core.

The soft compound of the middle part core also protects the hard part cores from cracking and also has the advantage of improving the ride comfort of the tire. The entire reinforcing profile can be made thinner than conventional reinforcing profiles, which also has a favorable effect on the ride comfort.

In an advantageous embodiment of the invention, it can be provided that the middle part core extends over at least 5%, in particular up to 40%, of the radial extension of the reinforcing profile between the belt and the bead. In practical embodiments of the invention, it may be provided that the Shore A hardness of the middle part of the core core is between 50 and 65, in particular between 55 and 60, and that the Shore A hardness of the upper part of the core and the lower part of the core between each 70 and 85, in particular between 75 and 80.

Furthermore, it can be provided that the central part of the core has the outline shape of a wedge or a trapezoid with axially outwardly directed broad base. Alternatively, it may be provided that the middle part-core has a double-concave shape or the outline of a hyperbola, or that the middle part-core is ogival-shaped. Preferred is an embodiment in which the middle sub-core has straight edges.

According to a particularly preferred embodiment, it is provided that the reinforcing profile is axially inside provided with an additional rubber layer which rests against the carcass, which may be provided in a practical development of the invention that the rubber layer has a thickness of 0.5 to 1 mm , According to a practical development, this rubber layer can consist of the same rubber compound as the middle part core, or, alternatively, of another rubber compound.

An inventive method for producing the pneumatic vehicle tire to extrude the reinforcing profile with its three sub-cores and the rubber layer as a common component to cut the extruded component and hang on the previously applied to the building drum air-tight inner layer.

To date, reinforcing profiles have been produced by means of calenders, which is problematic, in particular with regard to the dimensional stability of the reinforcing profile, until the end of the vulcanization. Furthermore, the uniformity of the reinforcing profiles was not always ensured; Shape changes, however, bring with it further negative influences, which is especially true with regard to air pockets during the construction and manufacturing process. This can now be effectively ruled out. Particularly advantageous is the simultaneous extrusion of rubber layer and reinforcing profile in view of the possibility of saving the usual additional process step of placing the rubber layer as a separate component on the carcass. The rubber layer was otherwise placed on the carcass otherwise than strips, which are referred to in the jargon as "squeegees" prior to placing the reinforcing profile. Now this additional process step can be omitted.

In principle, the method of extruding a component having three radial sections and an additional layer from the area of extruding treads is known, for example from EP 0 681 931 A1 and EP 0 798 142 B1. There it is used for completely different purposes. It can be considered as a merit of the inventors to have transferred such a process to the production of reinforcing profiles.

Further features, advantages and details of the invention will be described with reference to the drawing, which schematically illustrates an embodiment.

It shows

Rg. 1: a partial cross section through an embodiment of a radial tire according to the invention for passenger cars.

According to the partial cross section along an equatorial line shown in Fig. 1, the essential components constituting the illustrated tire are a profiled tread 1, a belt 2 consisting of two layers 2a in the embodiment shown, a carcass 3 in particular single-layered largely airtight running inner layer 4, beads 5 with bead cores 6 and bead core profiles 7, and side walls 8 and about crescent-shaped reinforcing profiles 9. The two layers 2a of the belt 2 consist in a known manner in particular in a rubber compound embedded steel cord reinforcing members extending parallel to each other within each ply, the steel cords of one ply 2a being oriented in intersecting relationship with the steel cords of the second ply 2a and each enclosing an angle between 15 ° and 30 ° with the tire circumferential direction. The carcass 3 can also be designed in a conventional and known manner and thus have reinforcing threads of a textile material or steel cord embedded in a rubber compound and extending in the radial direction. The carcass 3 is guided around the bead cores 6 from the inside to the outside, their elevations 3a extend in the direction of the belt 2 next to the bead core profiles 7.

The two made of elastomeric material, in particular of a rubber mixture, reinforcing profiles 9, of which in Fig. 1 only the right reinforcing profile 9 is shown, have been positioned during the construction of the tire on the inner layer 4 and are therefore located between this and the Carcass 3. The thickness of the reinforcing profiles 9 decreases both direction belt 2 and 5 direction bead. Direction belt 2 extends each reinforcing profile 9 to below the edge regions thereof. Over the vast majority of the length of the side wall of each reinforcing profile 9 is made almost constant thick, its strength is here up to 13 mm, in particular 9 to 11 mm.

Each reinforcing profile 9 in each case consists of three partial cores, namely a radially central partial core 10, a radially upper partial core 11 and a radially lower partial core 12.

Of particular importance is that the rubber mixture of the split cores 11, 12 and the split core 10 differ from each other in terms of hardness. The partial core 10 consists of a softer mixture having a Shore A hardness of 55 to 65, in particular 55 to 60 Shore A. The elastomeric mixture from which the split cores 11, 12 are produced has a Shore A hardness of 70 to 85, in particular 75 to 80 Shore-A. An additional rubber layer 13 is integrally formed on the reinforcing profile 9. The rubber layer, which has a thickness of 0.5 to 1 mm, conforms to the inner layer 4 and replaces the usual separate squeegees. The rubber layer 13 consists of the same rubber compound as the middle part of the core 10. The rubber layer 13, however, may also consist of a completely different rubber compound, so differ from the rubber compounds of the split cores 11 - 13.

The middle part of the core 10 may have different cross-sectional shapes. In dargestellen embodiment, it has the shape of a bar with two straight edges 14, 15, but other shapes are also conceivable. It is important that the middle, soft part of the core 10 is arranged in the bending region of the reinforcing profile 9 and designed so that in run-flat case, the two upper and lower split cores 11, 12 can be supported against each other, so that the runnability of the tire is guaranteed. On the other hand, in the normal operation of the gas-filled tire, the middle soft part core 10 is to produce a vibration damper between the upper and lower part cores. However, the illustrated embodiment with the two straight edges 14, 15 has been found to be particularly advantageous and is therefore preferred, especially because it can be produced easily.

According to the invention, the production of reinforcing profiles 9 according to the invention is carried out by a triplex extruder, in which at least two different rubber mixtures are fed in and extruded through an extrusion template for reinforcing profile 9 with upper partial core 11, middle partial core 10, lower partial core 12 and rubber layer 13. Such an extruded strip of material, which has an approximately trapezoidal cross section after extrusion, is then cooled and cut to size and finally transported to a tire building drum, where the reinforcing profile is placed on the inner layer and assembled with the other components to form a green tire. List of Reference Numerals (part of the description)

1 tread

2 belts

2a layers

3 carcass

4 inner layer

5 beads

6 bead core

7 bead core profile

8 side walls

9 reinforcement profile

10 middle part core

11 upper part core

12 lower part core

13 rubber layer

14 edge

15 edge

Claims

1. Pneumatic vehicle tire in radial design with a profiled tread, a multi-layer belt bandage, an inner layer, an at least single-layer carcass, which is guided around bead cores in bead areas, side walls and at least one each introduced in the region of each side wall, in cross-section crescent-shaped reinforcing profile, which each extending over at least a majority of the side wall length and consists of elastomeric materials of different hardnesses, characterized in that the reinforcing profile (9) consists of three radial split cores (10, 11, 12) and an axially outer rubber layer (13), wherein a radially upper Partial core (11) and a radially lower part of the core (12) each made of a hard elastomeric

Material exist, and a between the upper and lower part cores (11, 12) arranged radially central part core (10) consists of a soft elastomeric material.

2. pneumatic vehicle tire according to claim 1 or 2, characterized in that the middle Teilkem (10) over at least 5%, in particular up to 40%, of the radial extent of the reinforcing profile (9) between the belt (2) and bead (5) ,

3. Pneumatic vehicle tire according to one of claims 1 to 3, characterized in that the Shore A hardness of the central part of the core (10) between 50 and 65, in particular between 55 and 60, is.

4. Pneumatic vehicle tire according to one of claims 1 to 3, characterized in that the Shore A hardness of the upper part of the core (11) and the lower part of the core (12) is between 70 and 85, in particular between 75 and 80, respectively.

5. Pneumatic vehicle tire according to one of claims 1 to 4, characterized in that the central part core (10) has the outline shape of a wedge.

6. Pneumatic vehicle tire according to one of claims 1 to 4, characterized in that the central part of the core (10) has the outline shape of a trapezoid whose broader base is directed axially outward.

7. Pneumatic vehicle tire according to one of claims 1 to 4, characterized in that the central part core (10) has a double-concave shape.

8. Pneumatic vehicle tire according to one of claims 1 to 4, characterized in that the central part core (10) has the outline of a hyperbola.

9. Pneumatic vehicle tire according to one of claims 1 to 4, characterized in that the central part core (10) is ogival shaped.

10. Pneumatic vehicle tire according to one of claims 1 to 4, characterized in that the central part of the core (10) has straight edges (14,15).

11. Pneumatic vehicle tire according to one of claims 1 to 10, characterized in that the reinforcing profile (9) is axially outwardly provided with an additional rubber layer (13) which rests against the inner layer (4).

12. Pneumatic vehicle tire according to claim 11, characterized in that the rubber layer (13) has a thickness of 0.5 to 1 mm.

13. Pneumatic vehicle tire according to claim 11 or 12, characterized in that the rubber layer (13) and the central part core (10) consist of the same rubber compound.

14. Pneumatic vehicle tire according to claim 11 or 12, characterized in that the rubber layer (13) and the central part core (10) consist of different rubber compounds.

15. A method for producing a pneumatic vehicle tire having the features of at least claim 1, characterized in that the reinforcing profile with its three sub-cores (10, 11, 12) and the rubber layer (13) is extruded as a common component, wherein subsequently the extruded component cut and placed on the carcass.