DE102008003654B4 - Vehicle tires - Google Patents

Abstract

Vehicle tires, having a tread (2), side walls (13), bead areas (6,7) with tensile cores (6), a carcass (1) and a belt (3), the belt (3) being made up of at least one belt ply ( 3a, 3b), which is arranged radially above the carcass (1) between the carcass (1) and the tread (2) and which consists of rubberized reinforcement supports (9) arranged parallel to one another and spaced apart from one another, the reinforcement supports ( 9) are arranged longitudinally within the belt layer (3a, 3b) in such a way that their longitudinal axis (12) includes at least one belt angle (α)> 5 ° with the circumferential direction and at the edges (8) of the belt (3) in free Reinforcement ends (10) end with cut surfaces to form cut edges (11), characterized in that, when viewed from the belt, the cut edge (11) at the reinforcement end (10) includes a cutting edge angle (β) with the longitudinal axis (12) of the reinforcement (9) ß, which is at least 10 ° greater than the belt angle (α).

Description

The invention relates to a vehicle tire which has a tread, sidewalls, bead areas with tensile cores, a carcass and a belt, the belt being composed of at least one belt ply which is arranged radially above the carcass between the carcass and the tread and which is made of rubberized reinforcement supports arranged parallel to one another and spaced apart from one another, the reinforcement supports being arranged in such a way that their longitudinal axis encompasses at least a belt angle> 5 ° with the circumferential direction and at the edges of the belt in free cut surfaces with the formation of cut edges end up.

Vehicle tires with such a cut edge belt are known and sufficiently familiar to the person skilled in the art. The belt of pneumatic tires for passenger cars usually consists of 2 belt layers, whereby each layer has reinforcements parallel to one another and spaced apart from one another, mostly steel cords, with the reinforcements of the two layers rising in opposite directions so that the reinforcements of the two layers are oriented so that they cross one another, such as from the US 2006/0048879 A1 and U.S. 4,724,881 known. The reinforcements usually each enclose an angle between 20 ° and 35 ° with the tire circumferential direction. This angle is called the belt angle. The belt can be covered with a bandage. The belt of pneumatic truck tires usually consists of three or more belt layers, the strength members of which have specific belt angles. In the case of pneumatic radial tires, the belt ensures the rigidity of the tread in the longitudinal and transverse directions. This is used for power transmission when driving, improves cornering and reduces wear on the tire.

Cut edge belts are manufactured as a tire component in such a way that reinforcements, usually steel cords, aligned parallel and at a distance from one another, are surrounded in a calender with a rubber compound layer and thus form a long reinforcement layer web as a semi-finished product. From this sheet of layers, pieces of sheet are cut (cut to length) at an acute angle, e.g. by means of a pair of shears, and put together and spliced together again to form an elongated layer, so that the former cut surfaces, which arise during cutting to length, form the edges of the newly joined belt. In this way, a belt ply is produced in a simple manner, the strength supports of which are oriented at the desired angle deviating from the circumferential direction.

However, it is disadvantageous that in the area of the belt edges the reinforcements end in free ends with sharp cut edges. Because of the manufacturing process, the cut edges of each reinforcement end run parallel to the belt edge extension, which means that acute-angled and therefore particularly sharp cut edges are present. Depending on the belt angle of the belt ply, the cutting edge angle of the reinforcement supports is formed. It has been found that these sharp reinforcement ends can reduce tire life. Because the sharp edges of the reinforcement can initiate the finest cracks in the surrounding rubber material, which can increase with strong flexing of the tire in its operating state and lead to so-called belt edge separation, which reduces the service life of the vehicle tire. The cut edges are sharper, the smaller the angle of the reinforcement orientation of the belt ply arranged in the tire to the circumferential direction.

In the DE 36 29 955 A1 This problem is countered in the area of the belt edge of the vehicle tire by laying numerous strips in a shingle-like arrangement over the belt edge, so that the surface of the transition area is enlarged and the formation of cracks is stopped. This procedure is complex in terms of production technology, the tire is increased in its weight due to the increased use of material, whereby the rolling resistance of the tire is also disadvantageously increased. The also pursues a similar idea of a solution EP 0 319 588 B1 , according to which edge strips are laid in the entire edge area of the tread over the ends of the belt layers, which completely cover the transition area.

Next is from the EP 0 453 294 A2 known to provide pneumatic vehicle tires with a belt in which the longitudinal axis of its reinforcement is inclined relative to its circumferential direction by a small angle by two bands consisting of a rubber strip in which the reinforcement is embedded, from the outer ends of the tread of the pneumatic vehicle tire up to the center of the tread to be wrapped around its carcass.

The invention is based on the object of creating a vehicle tire which is improved in its durability in a simple and inexpensive way by avoiding belt edge separations.

The object is achieved in that the cutting edge at the end of the reinforcement member encloses a cutting edge angle with the longitudinal axis of each reinforcement member which is at least 10 ° greater than the belt angle.

It is thus achieved that the cutting angle at the end of the reinforcement is at least 10 ° more obtuse, as a result of which the sharpness of the cut edges at the end of the reinforcement is reduced. The risk of crack initiation, which can lead to belt edge separation, is reduced. The durability of the tire is increased.

In a preferred embodiment, the cutting edge of the reinforcement end forms an angle of 30 ° to 90 ° with the longitudinal extension (longitudinal axis) of the reinforcement; in a particularly preferred embodiment, the cutting edge forms an angle of 40 ° to 60 ° with the longitudinal extension of the reinforcement. The above-mentioned statements prevent the risk of belt edge separations being particularly effective, because the more obtuse the cutting edge angle, the less sharp are the cutting edges of the ends of the reinforcement members.

In the case of a multi-layer belt, all reinforcements of all layers of the belt can have the same cutting edge angle. In another embodiment, the reinforcements of the belt layers arranged one above the other can have different cutting edge angles of the reinforcement ends for each belt layer.

• 1 einen Querschnitt durch die Hälfte eines Fahrzeugluftreifens;
• 2 eine Aufsicht auf eine Gürtellage einer Ausführungsvariante des erfindungsgemäßen Fahrzeugluftreifens;
• 3 eine Aufsicht auf einen zweilagigen Gürtel in einer anderen Ausführungsvariante des erfindungsgemäßen Fahrzeugluftreifens.

Further features, advantages and details of the invention are explained in more detail with reference to the drawings, which represent schematic exemplary embodiments. It shows the:

• 1 a cross section through half of a pneumatic vehicle tire;
• 2 a plan view of a belt ply of an embodiment of the pneumatic vehicle tire according to the invention;
• 3 a plan view of a two-layer belt in another embodiment of the pneumatic vehicle tire according to the invention.

the 1 shows schematically the cross section through half of a radial tire for passenger cars. In the embodiment shown, the tire has a radial carcass that is single-ply 1 which contains, for example, polyester threads as reinforcing elements. The tire also has a profiled tread 2 , a belt consisting of two belt layers 3a, 3b 3 , an airtight inner layer 4th and bead areas each with a bead core 6th made of steel and a core profile 7th on which one on the bead core 6th and in the same way as this is arranged in a ring-shaped manner in the circumferential direction. The carcass 1 is axially inward to axially outward around the bead cores 6th folded around, its free end section, the carcass turn-up 1a, ends radially outside the core profiles 7th . The two belt layers 3a, 3b can be made from steel cord reinforcements embedded in a rubber mixture in a known manner 9 consist, the steel cords 9 in the two belt layers 3a, 3b parallel to each other, the steel cords 9 in one belt ply 3a, however, to the steel cords 9 run crossed in the other belt ply 3b, the angle (belt angle α ), which the steel cords enclose with the circumferential direction (arrow), is of the order of 20 °. The belt 3 is with a bandage 5 covered, which can also be carried out in a known manner, and contains, for example, nylon threads as a reinforcement. Each belt ply 3a, 3b consists of rubberized reinforcement supports arranged parallel to one another and spaced apart from one another 9 , with the reinforcement 9 Due to the manufacturing process on the edges 8th of the belt 3 in free reinforcement ends 10 with cut surfaces with the formation of cut edges 11 end, cf. 2 . A possible initiation of cracks in the area of the belt edge 8th at the contact point of the end of the reinforcement 10 to avoid the surrounding rubber material closes the cut edge 11 at the end of the reinforcement 10 with the longitudinal axis 12th of the reinforcement 9 a cutting edge angle β of about 60 °. The cutting edge angle β is at least 10 ° greater than the belt angle α is.

the 3 shows a plan view of a two-layer belt 3 with the two belt layers 3a, 3b in another variant of the pneumatic vehicle tire according to the invention. The left half of the figure shows both belt layers, the radially upper belt layer 3b being shown as transparent, whereby the radially lower belt layer 3a shines through. The right half of the drawing shows the belt ply 3a of 2 . Identical parts of the left and right halves of the drawing are denoted by the same reference numerals used on the right half of the drawing, but provided with inverted commas. The belt ply 3a is already in the 2 described in more detail. Above the belt layer 3a, the belt layer 3b is arranged, which likewise consists of rubberized reinforcement supports 9 ', the reinforcement supports 9' being the reinforcement supports 9 the layer 3a at a belt angle α cross from about 20 °. The cutting edges 11 'of each reinforcement end 10' are so pronounced that they have a cutting edge angle β of about 60 ° with the longitudinal axis 12 'of the reinforcement 9'.

The above-described invention can be used both for passenger vehicle tire belts and for truck tire belts, in particular within the working positions.

List of reference symbols

1

carcass

2

Treads

3

Belt position

4th

Inner layer

5

bandage

6th

Bead core

7th

Core profile

8th

Belt edge

9

Reinforcements

10

Reinforcement end

11

Cut edge

12th

Longitudinal reinforcement member

13th

Side wall

α

Belt angle

β

Cutting edge angle

Claims (5)

Vehicle tires, having a tread (2), side walls (13), bead areas (6,7) with tensile cores (6), a carcass (1) and a belt (3), the belt (3) being made up of at least one belt ply ( 3a, 3b), which is arranged radially above the carcass (1) between the carcass (1) and the tread (2) and which consists of rubberized reinforcement supports (9) arranged parallel to one another and spaced apart from one another, the reinforcement supports ( 9) are arranged longitudinally within the belt layer (3a, 3b) in such a way that their longitudinal axis (12) includes at least one belt angle (α)> 5 ° with the circumferential direction and at the edges (8) of the belt (3) in free Reinforcement ends (10) end with cut surfaces to form cut edges (11), characterized in that in the belt supervision the cut edge (11) at the reinforcement end (10) with the longitudinal axis (12) of the reinforcement (9) including a cutting edge angle (β) eat, which is at least 10 ° greater than the belt angle (α). Vehicle tires after Claim 1 , characterized in that the cutting edge (11) with the longitudinal axis (12) of the reinforcement (9) encloses a cutting edge angle (β) of 30 ° to 90 °. Vehicle tires after Claim 1 , characterized in that the cutting edge (11) with the longitudinal axis (12) of the reinforcement (9) encloses a cutting edge angle (β) of 40 ° to 60 °. Vehicle tire according to one of the preceding claims, characterized in that the belt (3) consists of several layers of belts (3a, 3b) arranged one above the other and the cut edges (11) of the reinforcement ends of all layers have the same cut edge angle (β). Vehicle tire according to one of the preceding claims, characterized in that the belt (3) consists of several belt plies (3a, 3b) arranged in layers one above the other and the cut edges (11) of the reinforcement ends 10) of different layers (3a, 3b) have different cut edge angles (β ) exhibit.

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