DE102021214497A1 - Vehicle Pneumatic Tires - Google Patents

Abstract

Pneumatic vehicle tires of radial design with an at least two-layer belt (2) and a one- or two-layer belt bandage (6) covering and covering this belt (2) with reinforcements running in the circumferential direction of the tire, each bandage layer having bandage sections (8) on the shoulder and an intermediate has this running central bandage section (7), wherein the reinforcements in the shoulder-side bandage sections (8) are hybrid cords (10) and in the central bandage section (7) are cords (9) made of polyamide 6.6 (PA 6.6), with both the hybrid cords (10) and the cords (9) made of PA 6.6 each consist of two end-twisted yarns. The hybrid cords (10) consist of a yarn made of polyethylene terephthalate (PET) and a yarn made of PA 6.6.

Description

The invention relates to a pneumatic vehicle tire of radial design with an at least two-layer belt and a one- or two-layer belt bandage covering and covering this belt with reinforcements running in the circumferential direction of the tire, each bandage layer having shoulder-side bandage sections and a central bandage section running between them, the Strength members in the shoulder-side bandage sections are the hybrid cords and in the central bandage section cords made of polyamide 6.6 (PA 6.6), both the hybrid cords and the cords made of PA 6.6 each consisting of two end-twisted yarns.

Such a vehicle tire is from DE 10 214 220 518 A1 known. In a preferred embodiment, the hybrid cords contained in the shoulder-side bandage sections consist of a high-modulus yarn and a low-modulus yarn. The high-modulus yarn consists of aramid fibre, carbon fibre, glass fiber or basalt, the low-modulus yarn consists of a polyamide, in particular PA 6.6. or of a polyester, in particular polyethylene terephthalate. The two yarns in the hybrid cord each have a fineness of at most 320 dtex, preferably at most 240 dtex. A pneumatic vehicle tire with a belt bandage with hybrid cords designed in this way in the shoulder-side bandage sections should have reduced rolling resistance and good high-speed suitability.

From the DE 10 2012 105 766 A1 discloses a pneumatic vehicle tire whose belt bandage contains exclusively hybrid cords as strength members, which consist of two end-twisted yarns, one yarn consisting of polyethylene terephthalate and the second yarn consisting of polyamide 6.6. In a preferred embodiment, the polyethylene terephthalate yarn has a fineness of 1,440 dtex, and the PA 6.6 yarn has a fineness of 1,400 dtex. A pneumatic vehicle tire with a bandage layer designed in this way should have low shrinkage behavior at the temperatures occurring during vulcanization of the tire and thereby ensure better dimensional stability of the vehicle tire.

The DE 10 2017 214 082 A1 deals with a hybrid cord as a reinforcement in a belt bandage of a pneumatic vehicle tire made from a high-modulus yarn and a low-modulus yarn. The fineness of the high-modulus yarn, which consists, for example, of polyethylene terephthalate, should be greater by a factor of at least 4 than the fineness of the low-modulus yarn, which consists of a polyamide, for example PA 6.6. Hybrid cords of this type in the belt bandage of pneumatic vehicle tires are said to have good suitability for high speeds, improved fatigue resistance and improved strength.

Apart from the less widespread use of hybrid cords in belt bandages of pneumatic vehicle tires, it is common for tires for passenger cars to use cords made from two yarns made from PA 6.6. Due to their widespread use, these bandage cords are readily available and comparatively inexpensive. A certain disadvantage of such cords in belt bandages is their low modulus, so that one layer more is often provided in the shoulder-side bandage sections, which cover the lateral edges of the belt layers, than in the central bandage section, in order to ensure high-speed suitability. A 3-2-3 or a 2-1-2 winding pattern results in the usual manufacturing process of the bandage layers by spirally winding an individual cord or cords embedded in rubber compound material. Viewed over the width of the tire or its tread, there is therefore an uneven winding pattern, which has a disadvantageous effect on the wear behavior of the tread. Especially with a 3-2-2 spool pattern, more heat is also generated in the shoulder-side areas, which in turn has an adverse effect on rolling resistance.

The invention is based on the object of being able to design the belt bandage in a pneumatic vehicle tire of the type mentioned at the outset with a uniform winding pattern, with the hybrid cord in the lateral bandage sections having good hysteresis behavior in order to reduce energy losses and positively influence rolling resistance. The hybrid cord should also enable an even winding pattern in the belt bandage in order to positively influence the wear behavior of the tread.

The stated object is achieved according to the invention in that the hybrid cords consist of a yarn made of polyethylene terephthalate (PET) and a yarn made of PA 6.6.

In pneumatic vehicle tires designed according to the invention, there are cords made from two identical yarns made from polyamide 6.6 in the middle section of the belt bandage, and hybrid cords made from a yarn made from polyamide 6.6 and a yarn made from polyethylene terephthalate in the two shoulder bandage sections. The hybrid cords in the shoulder-side bandage sections are characterized by better hysteresis behavior compared to the known hybrid cords, which reduces energy losses and rolling resistance. The high modulus of the hybrid cords makes it possible to use an "even" winding pattern in the belt bandage, for example a 1-1-1 or a 2-2-2 winding pattern, which is particularly advantageous for even wear of the tread.

In a preferred embodiment, the yarn made of PA 6.6 in the hybrid cords has a fineness of 700 dtex to 1880 dtex, and the yarn made of PET has a fineness of 550 dtex to 1840 dtex. With hybrid cords of this type, the belt bandages in tires for passenger cars or tires for light trucks can be optimally reinforced on the shoulder side while ensuring an even winding pattern.

Also preferred is an embodiment in which the two yarns in the hybrid cords have a fineness whose difference from one another is at most 25%, preferably at most 15%, determined from the yarn with the greater fineness. With such a largely balanced fineness of the two yarns in the hybrid cords, a balanced hysteresis behavior of the hybrid cords can be supported.

In addition, it is advantageous if the yarns made of PA 6.6 in the cords arranged there in the central bandage section have matching finenesses in the range from 700 dtex to 1880 dtex. Such "classically" executed PA 6.6 cords in the central bandage section have already proven themselves and can be well adapted to the hybrid cords in the shoulder-side bandage sections in terms of their hysteresis behavior and their module.

ermittelt. Twistfaktoren in den angegebenen Bereichen sind vor allem für die Ermüdungsbeständigkeit der Korde von Vorteil.According to a further preferred embodiment, the end-twisted yarns in the hybrid cords have a twist factor of 175 to 225, preferably 185 to 215, and in the central bandage section the end-twisted yarns made of PA 6.6 have a twist factor of 130 to 220, preferably 140 to 200. The twist factor comes from the relationship $$\text{twist factor}=\text{twist}\left[\text{t/m}\right]*{\left(\text{fineness}\left[\text{dtex}\right]/\mathrm{10,000}\right)}^{1/2},$$

determined. Twist factors in the specified ranges are particularly advantageous for the fatigue resistance of the cords.

In a further preferred embodiment, the hybrid cords contained in the shoulder bandage sections have the construction PET 1440×1+PA 6.6 1400×1 and the cords contained in the central bandage section have the construction PA 6.6 1400×2. Cords of this type are excellently suited for use in the belt bandage of tires for passenger cars and light trucks.

Depending on the speed index and the load exerted on the pneumatic vehicle tires, the belt bandage is made as a spool bandage with a spool pattern 1-1-1 or 2-2-2.

Further features, advantages and details of the invention will now be described using the exemplary embodiments described below and using the single figure, 1 , which schematically shows a cross section through the tread and belt area of a pneumatic vehicle tire.

Pneumatic vehicle tires designed according to the invention are tires of radial design, in particular for passenger cars, vans or light trucks. 1 shows a cross section through a pneumatic vehicle tire in the area of a profiled tread strip 1, wherein a belt 2, a carcass 3, an inner layer 4, the radially outer end sections of side walls 5 and a belt bandage 6 are also shown. The other components of the tire, such as bead areas with bead cores and bead cores, are not shown. As is known per se, the carcass 3 is clamped to the bead cores by wrapping it around the bead cores from the inside of the tire.

In the example, the belt 2 has a radially inner and a radially outer belt layer 2a, 2b, the radially inner belt layer 2a being wider than the radially outer belt layer 2b. The belt layers 2a, 2b consist of reinforcements embedded in a belt rubber coating, which are either steel cords consisting of several filaments or steel monofilaments, the reinforcements in each layer 2a, 2b being parallel to one another and at an acute angle of in particular 24° to 34° to the circumferential direction get lost. The reinforcements in one belt layer 2a cross the reinforcements in the other belt layer 2b.

The belt bandage 6 consists of a central bandage section 7 and two shoulder bandage sections 8, which cover the lateral edges of both belt layers 2a, 2b. The central bandage section 7 runs symmetrically to the in 1 indicated central center plane M of the tire, the arrangement of the two shoulder-side bandage sections 8 directly adjoining the central bandage section 7 is also symmetrical to the center plane M. Starting from the lateral edges of the radially inner, wider belt layer 2a, the shoulder-side bandage sections 8 protrude beyond these lateral edges outside by a width b _a of 2.00 mm to 20.00 mm, in particular from 5.00 mm to 20.00 mm, preferably from 5.00 mm to 15.00 mm. In the direction of the crown of the tire, the bandage sections 8 run from the lateral edges of the narrower belt layer 2b over a width b _i of 5.00 mm to 20.00 mm, in particular 10.00 mm to 20.00 mm, preferably 10.00 mm up to 15.00 mm. The widths b _i and b _a are the actual widths of the sections of the bandage sections 8.

At the preferred and in 1 shown embodiment, the two shoulder bandage sections 8 and the central bandage section 7 are each designed in two layers. Both the two layers in the central bandage section 7 and the two layers in the two shoulder bandage sections 8 consist of reinforcements embedded in a rubber material, a bandage rubber lining, which run in the circumferential direction of the tire or almost in the circumferential direction of the tire, in particular at an angle of up to 5 ° to the circumferential direction and parallel or largely parallel to each other.

In the central bandage section 7, the reinforcement cords 9 are made of polyamide 6.6 (PA 6.6), in the shoulder-side bandage sections 8 hybrid cords 10. The hybrid cords 10 each consist of two end-twisted yarns, one yarn made of polyethylene terephthalate (PET) and one yarn made of polyamide 6.6 ( PA 6.6). The cords 9 in the central bandage section 7 each consist of two end-twisted yarns made of PA 6.6. The PA 6.6 yarns in the cord 9 and in the hybrid cord 10 have a fineness of 700 dtex to 1880 dtex, in particular up to 1400 dtex. In the hybrid cord 10, the PET yarn has a fineness of 550 dtex to 1840 dtex, in particular up to 1440 dtex, with the difference in the fineness of the two yarns in the hybrid cord 10 being at most 25%, preferably at most 15%, in each case determined by the yarn with the larger one delicacy, amounts to.

• Hybridkord 10: 175 bis 225, bevorzugt 185 bis 215
• PA 6.6-Kord 9 im zentralen Bandagenabschnitt 7: 130 bis 220, bevorzugt 140 bis 200,
• mit folgender Definition des Twistfaktors:
  • Twistfaktor = Twist [t/m]*(Feinheit [dtex] / 10.000)^1/2, wobei t/m die Turns (Drehungen) pro Meter Kord sind.

Both the hybrid cords 10 and the cords 9 in the central bandage section 7 have end-twisted yarns in the Z-direction or in the S-direction, with the end-twisted yarns having the following twist factors:

• Hybrid cord 10: 175 to 225, preferably 185 to 215
• PA 6.6 cord 9 in the central bandage section 7: 130 to 220, preferably 140 to 200,
• with the following definition of the twist factor:
  • Twist Factor = Twist [t/m]*(fineness [dtex] / 10,000) ^1/2 , where t/m are the turns per meter of cord.

Table 1 contains examples of combinations of hybrid cords 10 and PA 6.6 cords 9. Table 1 Hybrid cord 10 in the shoulder bandage sections 8 PA 6.6 - cord 9 in central bandage section 7 PET 1840×1 + PA 6.6 1880×1 PA 6.6 1880×2 PET 1440×1 + PA 6.6 1400×1 PA 6.6 1400×2 PET 1100×1 + PA 6.6 940×1 PA 6.6 940×2 PET 1670×1 + PA 6.6 1880×1 PA 6.6 1880×2 PET 360×1 + PA 6.6 312×1 PA 6.6 312×2 PET 360×1 + PA 6.6 350×1 PA 6.6 350×2 PET 360×1 + PA 6.6 470×1 PA 6.6 470×2 PET 550×1 + PA 6.6 700×1 PA 6.6 700×2

The central bandage section 7 and the lateral bandage sections 8 are produced in particular as a spool bandage. In the case of a spool bandage, rubberized individual cords or a strip of cords embedded in a rubber mixture and running parallel to one another are spirally wound onto the belt 2 . The cords can be extruded directly into a rubberized strip. In an alternative embodiment, a wider web with cords running parallel to each other is calendered and cut into strips each with several cords.

At the in 1 shown embodiment of the belt bandage 6 from two layers results in a winding pattern, which is referred to as 2-2-2. In an alternative embodiment, there is a single-layer belt bandage with a 1-1-1 winding pattern.

Reference List

1

tread

2

Belt

2a, 2b

belt layer

3

carcass

4,

inner layer

5

Side wall

6

belt bandage

7, 8

bandage section

9, 10

cord

ba

Broad

bi

Broad

M

midplane

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 10214220518 A1 [0002]
• DE 102012105766 A1 [0003]
• DE 102017214082 A1 [0004]

Claims (8)

Pneumatic vehicle tires of radial design with an at least two-layer belt (2) and a one- or two-layer belt bandage (6) covering and covering this belt (2) with reinforcements running in the circumferential direction of the tire, each bandage layer having bandage sections (8) on the shoulder and an intermediate has this running central bandage section (7), wherein the reinforcements in the shoulder-side bandage sections (8) are hybrid cords (10) and in the central bandage section (7) are cords (9) made of polyamide 6.6 (PA 6.6), with both the hybrid cords (10) and the cords (9) made of PA 6.6 each consist of two end-twisted yarns, characterized in that the hybrid cords (10) consist of a yarn made of polyethylene terephthalate (PET) and a yarn made of PA 6.6. Vehicle pneumatic tires claim 1 , characterized in that in the hybrid cords (10) the yarn consisting of PA 6.6 has a fineness of 700 dtex to 1880 dtex, the yarn consisting of PET has a fineness of 550 dtex to 1840 dtex. Vehicle pneumatic tires claim 1 or 2 , characterized in that in the hybrid cords (10) the two yarns have a fineness, the difference between which is at most 25%, preferably at most 15%, determined from the yarn with the greater fineness. Pneumatic vehicle tires according to one of Claims 1 until 3 , characterized in that in the hybrid cords (10) the final twisted yarns have a twist factor of 175 to 225, preferably 185 to 215, with twist factor=twist [t/m]*(fineness [dtex]/10,000) ^1/2 , where t/m is the turns per meter of cord. Vehicle pneumatic tires claim 1 , characterized in that in the central bagage section (7) the yarns consisting of PA 6.6 in the cords (9) have matching gauges of 700 dtex to 1880 dtex. Vehicle pneumatic tires claim 1 or 5 , characterized in that in the central bagage section (7) the yarns made of PA 6.6 finally twisted in the cords (9) have a twist factor of 130 to 220, preferably 140 to 200, with twist factor = twist [t/m]*(fineness [ dtex] / 10,000) ^1/2 where t/m is the turns per meter of cord. Pneumatic vehicle tires according to one of Claims 1 until 6 , characterized in that the hybrid cords (10) contained in the shoulder bandage sections (8) have the construction PET 1440x1 + PA 6.6 1400x1 and the cords (9) contained in the central bandage section (7) have the construction PA 6.6 1400x2. Pneumatic vehicle tires according to one of Claims 1 until 7 , characterized in that the belt bandage (6) is a winding bandage with the winding pattern 1-1-1 or 2-2-2.

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