DE102016223304B4 - 2Vehicle pneumatic tyres - Google Patents

Abstract

Pneumatic vehicle tire with a carcass (2), a tread strip (6) and a belt (7), which is covered on its radially outer side by a belt bandage (8) with reinforcements oriented approximately in the circumferential direction, the belt bandage having at least one belt bandage layer (8) which - seen in the tire cross section - consists of three sections arranged next to one another, namely a middle section (10) and a side section (11, 12) adjoining the middle section (10) and wherein the reinforcements of the middle section (10) are cords made of polyamide 6.6 of a particular cord construction, the side section cords (11, 12) being of the same construction as the center section cords (10) and the side section cords (11, 12) being of a single material which is at least 20% higher tenacity at a temperature of 80°C and an elongation of 4% than the polyamide 6.6 of the center section, where the tenacity is determined according to ASTM D885-16.

Description

The invention relates to a pneumatic vehicle tire with a carcass, a tread strip and a belt, which is covered on its radially outer side by a belt bandage with reinforcements oriented approximately in the circumferential direction, the belt bandage having at least one belt bandage layer which—viewed in the tire cross section—consists of three side by side arranged sections, namely a middle section and in each case a side section adjoining the middle section and wherein the strength members of the middle section are cords made of polyamide 6.6 of a specific cord construction.

It is well known to arrange a belt bandage in pneumatic vehicle tires. The belt bandage has one or more layers, covers the edges of the belt and has reinforcements running parallel and approximately in the circumferential direction in the form of cords embedded in a rubber mixture. "Approximately circumferential" means an angle of 0° to 5° with respect to the tire circumferential direction.

During tire manufacture, the belt bandage is applied in the form of layers, strips or individual reinforcements with reinforcements embedded in an unvulcanized rubber mixture, which are wound or spooled onto the belt. The reinforcements are embedded in rubber by a group of substantially parallel thread-like reinforcements, which are usually thermally and/or pretreated with an impregnation for better adhesion to the embedding rubber in a manner known to the person skilled in the art, in the longitudinal direction a calender or passes through an extruder for coating with the rubber compound. Alternatively, reinforcements are used that are impregnated in a sticky manner and can be processed without a calendered adhesive mixture.

The belt bandage is used, particularly in high-speed use, to limit tire elevation due to the centrifugal forces that occur when driving. In addition, the reinforcements of the belt bandage should hold down the belt layers, in particular the belt edges, for high-speed strength and durability. For this, greater forces must be bound in the shoulder areas of the pneumatic vehicle tire than in the central area.

It is known that a reinforcement made of polyamide 6.6 (PA6.6) has low thermal stability, i.e. the modulus of this reinforcement decreases at higher temperatures. For the tire, this means that the modulus of PA6.6 reinforcements decreases when the tire temperature increases, which occurs particularly in high-speed use. The belt bandage with PA6.6 strength members could therefore no longer assume the desired function of holding down the belt edges in particular.

Therefore, the side sections of the bandage are designed to be “stronger”. Up to now, this has been done by additional edge strips and/or by choosing a different material and/or a greater thickness of the reinforcements of the side sections.

From the previously unpublished DE 10 2016 202 930.4 a pneumatic vehicle tire according to the preamble is known. The pneumatic vehicle tire has a belt bandage layer made up of three sections, a middle section and two side sections. Cords made of PA6.6 are arranged in the middle section and hybrid cords made of aramid and PET or aramid and PA6.6 are arranged in the side sections. The hybrid cords have a desirably higher modulus of elasticity (modulus), but also a different cord construction, also in terms of yarn counts, as a result of which the belt bandage is thicker in the side section than in the middle section.

The increased use of material creates disadvantages in terms of tire rolling resistance and cost. In addition, a belt bandage of unequal thickness causes disadvantages in terms of tire wear.

It is therefore the object of the present invention to provide a high-speed resistant pneumatic vehicle tire with a belt bandage, which has improved rolling resistance and more uniform wear and which can be manufactured more cost-effectively.

The object is achieved according to the invention in that the cords of the side section have the same construction as the cords of the middle section and that the cords of the side section are made of a single material which has at least 20% higher tenacity a temperature of 80°C and an elongation of 4% than the polyamide 6.6 of the center section, the tenacity being determined according to ASTM D885-16.

The cords of the side section are identical in construction to the cords of the middle section, but are made of a different material. As a result, the side sections and the middle section are of the same thickness, which has a positive effect on tire wear. The side section cord is not a hybrid cord, but the yarns of this cord are made of one and the same material. The material of the side section has better thermal stability than the PA6.6 of the middle section, so that the tenacity is at least 20% higher than that of PA6.6. This desirably holds down the belt edges in high speed operation. There are no additional edge strips arranged.

In a particular embodiment of the invention, the material of the side portion cords is Polyamide 4.6 (PA4.6). PA4.6 has higher thermal stability than PA6.6, which makes the tenacity of PA4.6 higher than PA6.6 at higher temperatures.

The table below shows the beneficial properties of PA 4.6 cords compared to PA 6.6 cords in terms of modulus at 80°C: Cord construction 470x2 PA 4.6 PA 6.6 Twist [t/m] 420 420 LASE 4% at 80°C [N] 10.1 7.8 LASE 4% at 80°C [mN/tex] 107 83

The force-elongation data are determined according to ASTM D885-16.

LASE stands for Load At Specific Elongation and means here in the table the strength related to the fineness at a temperature of 80°C and an elongation of 4%.

It can be seen that the PA 4.6 cord has a 29% higher tenacity at 80°C than a comparable cord made of PA 6.6, whereby advantages of a pneumatic vehicle tire having this PA 4.6 cord in the side section of the belt bandage are achieved at high speed.

It is expedient if each cord has the construction x2 or the construction x3 and is arranged in a density of 60 to 200 epdm, preferably 80 epdm to 160 epdm.

Depending on the fineness of the cords, sufficient strength with regard to the tire properties is achieved in these areas and, in addition, a sufficient distance between the cords is ensured, so that there is sufficient rubber between the cords.

It is advantageous if each cord has the construction 470x2 and is arranged in a density of 90 to 180 epdm, preferably 130 epdm, or if each cord has the construction 940x2 and in a density of 70 to 140 epdm, preferably 80 epdm , is arranged.

Depending on the fineness of the cords, sufficient strength with regard to the tire properties is achieved in these areas and, in addition, a sufficient distance between the cords is ensured, so that there is sufficient rubber between the cords.

It is expedient if each of the two side sections of the belt bandage layer has an axial width of 3% to 47%, preferably 5% to 30%, particularly preferably 10% to 20%, of the axial width of the belt bandage layer, measured along the contour of the belt bandage location.

This achieves good force distribution over the belt width in the high-speed range, which is further improved in the preferred areas.

In a specific embodiment of the invention, the belt bandage is designed in one layer and consists of the middle section and the two side sections. A rolling resistance and cost advantage is achieved through the single-ply design.

In an alternative embodiment of the invention, a further belt bandage layer is arranged, which is arranged radially inward in relation to the belt bandage layer consisting of three sections and in which this further belt bandage layer has reinforcements made of PA6.6 over its entire axial width. This achieves an additional module increase.

In another alternative embodiment of the invention, the belt bandage has a 2-layer design and another belt bandage layer is therefore arranged, which also consists of three sections and has reinforcements made of PA6.6 in the middle section and reinforcements made of PA4.6 in the side sections.

The twist of the yarns is in one direction (S or Z) and the cord twist is opposite to the yarn twist (Z or S).

The twist factor α of each multifilament yarn or cord is in a range from 100 to 250, preferably in a range from 120 to 180, where α=twist [t/m] × (fineness [tex]/1000) ^1/2 .

The pneumatic vehicle tire according to the invention is preferably a passenger car tire or a commercial vehicle tire.

• 1 einen Querschnitt durch einen Fahrzeugluftreifen;
• 2 einen Querschnitt einer Gürtelbandage mit einer einzigen Gürtelbandagenlage eines erfindungsgemäßen Fahrzeugluftreifens;
• 3 einen Querschnitt einer anderen Gürtelbandage mit zwei Gürtelbandagenlagen eines anderen erfindungsgemäßen Fahrzeugluftreifens.

Further features, advantages and details of the invention will now be described in more detail with reference to the figures, which represent schematic exemplary embodiments. The shows:

• 1 a cross section through a pneumatic vehicle tire;
• 2 a cross section of a belt bandage with a single belt bandage layer of a pneumatic vehicle tire according to the invention;
• 3 a cross section of another belt bandage with two belt bandage layers of another pneumatic vehicle tire according to the invention.

the 1 shows a radial cross-section through a pneumatic vehicle tire for a passenger car. The essential components that make up the pneumatic vehicle tire shown are a largely air-impermeable inner layer 1, a carcass 2, which extends in the conventional manner from the crown area of the pneumatic vehicle tire via the side walls 3 to the bead areas 4 and is anchored there by wrapping high-tensile bead cores 5 , a profiled tread 6 located radially above the carcass and a belt 7 which is arranged between the tread 6 and the carcass 2 and contains two reinforcement layers, which is covered radially on the outside with a belt bandage which comprises a single belt bandage layer 8 . The belt bandage layer 8 covers the belt edges 9 and has reinforcements which are wound parallel and approximately in the circumferential direction of the pneumatic vehicle tire along its axial width.

the 2 shows a cross section of a belt bandage of a pneumatic vehicle tire with a single belt bandage layer 8 according to the invention. The belt bandage layer 8 has reinforcements arranged approximately in the circumferential direction and consists of three sections arranged next to one another: a middle section 10 and a side section 11, 12 adjoining the middle section 10. The middle section 10 has cords of the construction 470x2 made of PA6.6. According to the cord construction, two first-twisted yarns each with a yarn count of 470 dtex made of PA6.6 are end-twisted with one another. These cords are arranged in the center section 10 at a density of 130 epdm. The side sections 11, 12 have cords of the same construction but of PA4.6. The cords of the side portions 11, 12 are arranged at a density of 130 epdm.

the 3 shows a cross section of another belt bandage with two belt bandage layers 8, 13 of a pneumatic vehicle tire according to the invention. The radially outer belt bandage layer 8 is the same as in 2 described belt bandage layer constructed and consists of three axially adjacent sections arranged shoulder section 11 - middle section 10 - shoulder section 12. Radially inside this consisting of three sections 10, 11, 12 belt bandage layer 8 another belt bandage layer 13 is arranged. This further belt bandage layer 13 has the same cord made of PA6.6 of the same construction as in the middle section 10 over its entire axial width, which is arranged with a density of 130 epdm.

Reference List

1

inner layer

2

carcass

3

Side wall

4

bead area

5

bead core

6

tread

7

Belt

8th

belt bandage location

9

belt edge

10

middle section

11

side section

12

side section

13

another belt bandage layer

rR

radial direction

aR

axial direction

Claims (9)

Pneumatic vehicle tire with a carcass (2), a tread strip (6) and a belt (7), which is covered on its radially outer side by a belt bandage (8) with reinforcements oriented approximately in the circumferential direction, the belt bandage having at least one belt bandage layer (8) which - seen in the tire cross section - consists of three sections arranged next to one another, namely a central section (10) and a side section (11, 12) adjoining the central section (10) and wherein the reinforcements of the central section (10) are cords made from polyamide 6.6 of a particular cord construction, the side section cords (11, 12) being of the same construction as the center section cords (10) and the side section cords (11, 12) being of a single material which is at least 20% higher tenacity at a temperature of 80°C and an elongation of 4% than the polyamide 6.6 of the center section, where the tenacity is determined according to ASTM D885-16. Vehicle pneumatic tires claim 1 , characterized in that the material of the cords of the side portion (11, 12) is polyamide 4.6. Vehicle pneumatic tires claim 1 or 2 , characterized in that each cord of the belt bandage layer (8, 13) has the construction x2 or the construction x3 and is arranged in a density of 60 to 200 epdm, preferably 80 to 160 epdm. Vehicle pneumatic tires claim 3 , characterized in that each cord belt bandage layer (8, 13) has the construction 470x2 and is arranged in a density of 90 to 180 epdm, preferably 130 epdm. Vehicle pneumatic tires claim 3 , characterized in that each cord belt bandage layer (8, 13) has the construction 940x2 and is arranged in a density of 70 to 140 epdm, preferably 80 epdm. Pneumatic vehicle tire according to one of the preceding claims, characterized in that each of the two side sections (11, 12) belt bandage layer (8) has an axial width of 3% to 47%, in particular from 5% to 30%, in particular from 10% to 20%, of the axial width of the belt bandage layer (8), measured along the contour of the belt bandage layer (8). Pneumatic vehicle tire according to one of the preceding claims, characterized in that the belt bandage (8) is constructed in one layer and consists of the central section (10) and the two side sections (11, 12). Pneumatic vehicle tire according to at least one of the preceding claims, characterized in that the belt bandage is constructed in two layers and thus a further belt bandage layer (13) is arranged which extends radially inwards from the belt bandage layer (8) consisting of three sections (10, 11, 12). is arranged and that this further belt bandage layer (13) has reinforcements made of PA6.6 over its entire axial width. Pneumatic vehicle tires according to at least one of the preceding Claims 1 - 7 , characterized in that the belt bandage is designed in two layers and thus another belt bandage layer is arranged, which also consists of three sections and has reinforcements made of PA6.6 in the middle section and reinforcements made of PA4.6 in the side sections.

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