Agricultural tires

Abstract

The invention relates to an agricultural tire with two sidewalls (4), a belt assembly (2) with at least two belt layers (2a) and a tread (1) with two rows of studs (10a) forming a V-shape across the tread width in plan view. In each shoulder area, between the sidewall (4) and the tread (1), at least one shoulder reinforcement strip (11) is installed, which is spaced apart from the belt layers (2a) in the axial direction and has textile cords (11d) embedded in a strip rubber coating and running at an angle of 0° to 15° to the circumferential direction.

Description

[0001] The invention relates to an agricultural tire with two sidewalls, a belt assembly with at least two belt layers and a tread with two rows of studs forming a V-shape across the tread width when viewed from above.

[0002] Agricultural tires with such lug profiles have been known and common for a long time and are used particularly as traction tires on agricultural tractors and other agricultural machinery.

[0003] An agricultural tire of the type mentioned above is known, for example, from EP 0 795 427 A1. This agricultural tire has a tread with two rows of studs extending across the tread width in a V-shape when viewed from above, each with a stud section on the outside of the tread extending at an angle of greater than 60° and less than 90° to the circumferential direction, and a stud section on the inside of the tread extending at an angle of less than 40° to the circumferential direction. Such studs are said to be beneficial for handling performance.

[0004] In agricultural tires, the lugs of the tread pattern are extremely rigid, which means that significant forces are transferred to the tire interior via the deforming lugs as the tire rolls. This poses the risk of cracks in the inner layer of the agricultural tire, causing it to leak and subsequently losing air (pressure loss).

[0005] The invention is therefore based on the object of noticeably reducing the risk of cracks occurring in the inner layer of an agricultural tire of the type mentioned above.

[0006] The stated object is achieved according to the invention in that in each shoulder area between the sidewall and the tread at least one shoulder reinforcement strip is installed, which is spaced apart from the belt layers in the axial direction and has textile cords embedded in a strip rubber coating and running at an angle of 0° to 15° to the circumferential direction.

[0007] Due to their textile cords oriented in the circumferential direction or essentially in the circumferential direction, the shoulder reinforcement strips "absorb" the forces acting via the lugs towards the tire interior and thus reinforce the shoulder areas in such a way that the inner layer is protected much better than before against the occurrence of cracks.

[0008] According to a preferred embodiment, the textile cords in the shoulder reinforcement strip are arranged with a cord density of 75 epdm to 115 epdm, in particular 80 epdm to 110 epdm, preferably 85 epdm to 105 epdm, and particularly preferably 90 epdm to 100 epdm. Shoulder reinforcement strips designed in this way absorb the aforementioned forces particularly effectively.

[0009] Another preferred embodiment provides for the textile cords of the shoulder reinforcement strip to run circumferentially. This measure also contributes to further improving the protection of the inner layer against tears.

[0010] According to an advantageous variant, the shoulder reinforcement strip contains exclusively the textile cords running at an angle of 0° to 15° to the circumferential direction.

[0011] According to an alternative, advantageous variant, the shoulder reinforcement strip contains a fabric which contains the textile cords running at an angle of 0° to 15° to the circumferential direction and further textile cords.

[0012] Preferably, the shoulder reinforcement strip has a thickness of 1.00 mm to 3.00 mm, in particular 1.50 mm to 2.50 mm, determined between the inner side of the strip located on the respective side wall and the outer side of the strip located on the tread.

[0013] A further preferred embodiment provides that the shoulder reinforcement strip, viewed in the tire cross-section, has an extension length of 30.0 mm to 200.0 mm, in particular of up to 150.0 mm, preferably of up to 100.0 mm, preferably of up to 70.0 mm, particularly preferably of 35.0 mm to 55.0 mm, most preferably of 40.0 mm to 50.0 mm.

[0014] The position of the shoulder reinforcement strip is preferably such that, viewed in the tire cross-section, the shoulder reinforcement strip is divided into two strip parts by an auxiliary line running axially through the edge of the tread base, each of which has an extension length of 45% to 55%, in particular 47% to 53%, of the extension length of the shoulder reinforcement strip determined in the tire cross-section. The shoulder reinforcement strip is therefore positioned in a somewhat centered position with respect to the lateral tread end, thereby very effectively reinforcing the particularly heavily stressed areas and thus also providing particularly effective protection for the inner layer against cracks.

[0015] According to a further preferred embodiment, the shoulder reinforcement strip has an outer strip end which is furthest away from the tire equatorial plane and which, viewed in the tire cross-section, has a distance of 10.0 mm to 30.0 mm, in particular 15.0 mm to 25.0 mm, from the nearest outer tire tread end in the radial direction.

[0016] In the latter embodiment, an advantageous further development consists in the fact that the tread ends on the outside of the tyre, viewed in the tyre cross-section, are located radially outside the point with the cross-sectional width of the agricultural tyre and have a distance from this, determined in the radial direction, of in particular 5.0 mm to 25.0 mm.

[0017] It is also preferred if the shoulder reinforcement strip runs circumferentially. This optimizes load distribution across the tire circumference, further improving the protection of the inner layer.

[0018] Furthermore, according to a further embodiment, it is preferred if several shoulder reinforcement strips are installed in at least one tire shoulder, preferably in each tire shoulder, each of which preferably extends over at least 10% of the tire circumference. This measure also optimizes the load distribution across the tire circumference, thereby further improving the protection of the inner layer.

[0019] In the latter design, it is advantageous to install a shoulder reinforcement strip radially inside each lug in each tread half. This provides a shoulder reinforcement strip for each area subject to particularly high wear.

[0020] According to a further preferred embodiment, the textile cords of the shoulder reinforcement strip have a diameter of 0.40 mm to 0.60 mm, preferably 0.45 mm to 0.55 mm. Such cords are particularly well suited for absorbing the forces acting via the studs toward the tire interior.

[0021] The textile cord of the shoulder reinforcement strip is preferably a 1440 dtex x 2 polyester cord.

[0022] Further features, advantages and details of the invention will now be described in more detail with reference to the drawing, which schematically shows an embodiment of the invention. Fig. 1 a schematic cross-section through an agricultural tire with an embodiment of the invention and Fig. 2 a plan view of a circumferential section of the tread of the agricultural tire from Fig. 1.

[0023] Agricultural tires designed according to the invention are in particular vehicle tires for agricultural tractors, for example for harvesting machines, such as potato harvesters or combine harvesters, and preferably pneumatic vehicle tires of radial design for rims with a rim diameter of 20 inches to 42 inches.

[0024] Fig. 1 shows a cross-section through an agricultural tire with a tread 1, a belt assembly 2, a multi-layer carcass insert 3, sidewalls 4, an inner layer 5 and bead regions 6, each comprising a bead core 7, an apex 8 and a horn profile 9 with a bead toe 9a.

[0025] The tire equatorial plane is indicated by a line AA, the radial direction by a double-headed arrow R, and the axial direction by a double-headed arrow A. For the purposes of the present invention, the "radial direction" refers to the direction running in the tire cross-section in and parallel to the tire equatorial plane. Furthermore, the "axial direction" refers to the direction parallel to the tire axis, i.e., the direction running perpendicular to the tire equatorial plane in the tire cross-section.

[0026] In Fig. Figure 1 shows the cross-sectional width B of the agricultural tire, measured in the axial direction. According to ETRTO standards, the cross-sectional width B is "the distance between the outer edges of the sidewalls of the inflated tire, excluding raised areas caused by lettering, decorative ribs, and scuff guards." Tire measurements are taken on an unloaded tire mounted on its measuring rim and inflated to the recommended tire pressure.

[0027] Fig. Figure 2 shows a plan view of the tread 1. The tread 1 has a lug profile with two rows 10 of lugs, each consisting of circumferentially successive, spaced-apart, parallel-aligned lugs 10a. The lugs 10a extend in a V-shape across the tread width and from the respective tread edge to the tread center, and the lugs 10a from one row 10 are offset from one another in the circumferential direction relative to the lugs 10a from the other row 10. The tread 1 further has a tread base 1b that defines it radially inwardly, extends between the lugs 10a, and is defined at the edges of the tread 1 by peripheral edges 1b' extending between each two consecutive lugs 10a and in the circumferential direction. Fig. 1 further shows, the tread 1, viewed in the tire cross-section, has two tread ends 1a located on the sidewalls 4, on the outside of the tire, which are located radially outside the point with the cross-sectional width B and have a distance a1 from this, determined in the radial direction, of 5.0 mm to 25.0 mm.

[0028] According to Fig. 1, the carcass ply 3 has three superimposed carcass plies 3a, each consisting of carcass cords embedded in a carcass rubber lining and running parallel to one another within the carcass plies 3a. The carcass cords are oriented at an angle of 85° to 90° to the circumferential direction, with the carcass cords running in immediately adjacent carcass plies 3a being arranged so as to cross one another. The carcass plies 3a run between the belt assembly 2 and the inner layer 5, between the sidewalls 4 and the inner layer 5 and between the horn profiles 9 and the inner layer 5. The two carcass plies 3a closest to the inner layer 5 are folded over in the bead areas 6 around the bead cores 7 from the inside of the tire to the outside of the tire and each end on the outside of the tire with a carcass turn-up 3a' located in the area of ​​the respective horn profile 9.The radially outermost carcass ply 3a, which is furthest away from the inner layer 5, is not folded over the bead cores 7, but runs in the bead areas 6 on the outside of the tire over the carcass turn-ups 3a' of the two other carcass plies 3a and ends in the area next to the respective bead filler 8 or in the area next to the respective bead core 7. The carcass cords are in particular textile cords, for example aramid cords.

[0029] The belt assembly 2 has four belt plies 2a, each with two belt edges 2a''', wherein the belt plies 2a each consist of belt cords, preferably textile cords, embedded in a belt rubber coating, in particular designed and oriented in a known manner, wherein the belt cords in adjacent belt plies 2a preferably cross one another. The radially innermost belt ply 2a extends with a central belt ply section 2a' in contact with the radially outermost carcass ply 3a and, viewed in the tire cross-section, has two edge-side belt ply sections 2a'' encompassing the belt edges 2a''', which do not contact the corresponding carcass ply 3a but protrude from it.

[0030] The sidewalls 4 pass the point of cross-sectional width B, each overlapping the corresponding horn profile 9 with a tapered, radially inner wall section 4a on the outside, and each have a radially outer wall section 4b extending between the corresponding edge-side belt ply section 2a'' and the radially outermost carcass ply 3a. The agricultural tire therefore has a so-called "sidewall under belt" construction (SUB construction).

[0031] The inner layer 5 covers the inside of the agricultural tire, consists of an airtight rubber material and extends into the area of ​​the bead toes 9a of the horn profiles 9.

[0032] In the area radially within each row of studs 10 ( Fig. 1), at least one shoulder reinforcement strip 11 is installed between the respective sidewall 4 and the tread 1, spaced apart from the belt layers 2a and from the respective outer tread end 1a of the tire. More preferably, one shoulder reinforcement strip 11 is provided extending around the tire circumference. Alternatively, several shoulder reinforcement strips 11 can be provided, each preferably extending over at least 10% of the tire circumference, with one shoulder reinforcement strip 11 being installed radially within each lug 10a.

[0033] Each shoulder reinforcement strip 11 has, viewed in the tire cross-section, an extension length cs measured along the shoulder reinforcement strip 11 of 30.0 mm to 200.0 mm, in particular of up to 150.0 mm, preferably of up to 100.0 mm, more preferably of up to 70.0 mm, particularly preferably of 35.0 mm to 55.0 mm, most preferably of 40.0 mm to 50.0 mm, and a thickness ss of 1.00 mm to 3.00 mm, in particular of 1.50 mm to 2.50 mm, wherein the thickness ss is determined as the smallest possible distance between the inside of the strip lying on the respective sidewall 4 and the outside of the strip lying on the tread 1.

[0034] Each shoulder reinforcement strip 11 further has an outer strip end 11a which is furthest away from the tire equatorial plane (line AA) and an inner strip end 11b which is closest to the tire equatorial plane (line AA) and spaced from the belt layers 2a. The outer strip end 11a has, as viewed in the tire cross-section, a distance a2 from the respective tire outer tread end 1a in the radial direction of 10.0 mm to 30.0 mm, in particular of 15.0 mm to 25.0 mm. As viewed in the tire cross-section, the shoulder reinforcement strip 11 is formed by a groove extending in the axial direction through the respective edge 1b' (cf. Fig. 2) auxiliary line h1 is divided into two strip parts 11c, each with an extension length csc of 45% to 55%, in particular of 47% to 53%, of the extension length cs.

[0035] Each shoulder reinforcement strip 11 consists of textile cords 11d embedded side by side in a rubberized strip, which are oriented in the circumferential direction, i.e., run in the circumferential direction. The textile cords 11d each have a maximum diameter (diameter at the thickest point) of 0.40 mm to 0.60 mm, preferably 0.45 mm to 0.55 mm, are made of polyester, for example, and have a construction of 1440 dtex x 2, for example. In each shoulder reinforcement strip 11, the textile cords 11d are arranged with a cord density of 75 epdm ("ends per decimeter") to 115 epdm, in particular 80 epdm to 110 epdm, preferably 85 epdm to 105 epdm, and particularly preferably 90 epdm to 100 epdm. The strip rubber coating should preferably match the belt rubber coating.

[0036] The invention is not limited to the described embodiment.

[0037] The carcass ply 3 comprises, in particular, up to four carcass plies. The textile cords 11d in the shoulder reinforcement strips 11 run adjacent to one another within the shoulder reinforcement strips 11, i.e., without crossing, and at an angle of 0° to 15° to the circumferential direction. The shoulder reinforcement strips 11 can each comprise a fabric made of textile cords, with the textile cords running at an angle of 0° to 15° to the circumferential direction being part of the fabric. The agricultural tire does not have to have a SUB construction. List of reference symbols 1 tread 1a outer tire tread end 1b Tread base 1b' edge 2 belt bandage 2a Belt position 2a' central belt layer section 2a'' edge belt layer section 2a''' Belt edge 3 Carcass insert 3a Carcass ply 3a' Carcass high-stroke 4 side wall 4a radial inner wall section 4b radial outer wall section 5 inner layer 6 Bead area 7 Bead core 8 core riders 9 Horn profile 9a bulging toe 10 rows of tunnels 10a tunnel 11 shoulder reinforcement strips 11a outside strip end 11b inside strip end 11c strip part 11d textile cord A Double arrow (axial direction) AA line (tyre equatorial plane) B cross-sectional width a1, a2 distance c S , c SC Extension length h1 auxiliary line R double arrow (radial direction) s S Strength QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] EP 0 795 427 A1

[0003]

Claims

[1] Agricultural tire with two sidewalls (4), a belt assembly (2) with at least two belt layers (2a) and a tread (1) with two rows of studs (10) forming a V-shape across the tread width in plan view, characterized in that in each shoulder region between the sidewall (4) and the tread (1) at least one shoulder reinforcement strip (11) is installed, which is spaced apart from the belt layers (2a) in the axial direction and has textile cords (11d) embedded in a strip rubber coating and running at an angle of 0° to 15° to the circumferential direction. [2] Agricultural tyre according to claim 1, characterized by that the textile cords (11d) in the shoulder reinforcement strip (11) are arranged with a cord density of 75 epdm to 115 epdm, in particular of 80 epdm to 110 epdm, preferably of 85 epdm to 105 epdm, particularly preferably of 90 epdm to 100 epdm. [3] Agricultural tyre according to claim 1 or 2, characterized by that the textile cords (11d) of the shoulder reinforcement strip (11) run in the circumferential direction. [4] Agricultural tyre according to one of claims 1 to 3, characterized by that the shoulder reinforcement strip (11) contains exclusively the textile cords (11d) running at an angle of 0° to 15° to the circumferential direction. [5] Agricultural tyre according to one of claims 1 to 3, characterized by that the shoulder reinforcement strip (11) contains a fabric which contains the textile cords (11d) running at an angle of 0° to 15° to the circumferential direction and further textile cords. [6] Agricultural tyre according to one of claims 1 to 5, characterized bythat the shoulder reinforcement strip (11) has a thickness (ss) of 1.00 mm to 3.00 mm, in particular of 1.50 mm to 2.50 mm, determined between the inner side of the strip lying on the respective side wall (4) and the outer side of the strip lying on the tread (1). [7] Agricultural tyre according to one of claims 1 to 6, characterized by that the shoulder reinforcement strip (11), viewed in the tire cross-section, has an extension length (cs) of 30.0 mm to 200.0 mm, in particular of up to 150.0 mm, preferably of up to 100.0 mm, more preferably of up to 70.0 mm, particularly preferably of 35.0 mm to 55.0 mm, most preferably of 40.0 mm to 50.0 mm. [8] Agricultural tyre according to one of claims 1 to 7, characterized bythat the shoulder reinforcement strip (11), viewed in the tire cross-section, is divided into two strip parts (11c) by an auxiliary line (h1) running in the axial direction through the edge (1b') of the tread base (1b), which strip parts each have an extension length (csc) of 45% to 55%, in particular of 47% to 53%, of one or the extension length (cs) of the shoulder reinforcement strip (11) determined in the tire cross-section. [9] Agricultural tyre according to one of claims 1 to 8, characterized by that the shoulder reinforcement strip (11) has an outer strip end (11a) which is furthest away from the tire equatorial plane (line AA) and which, viewed in the tire cross-section, has a distance (a2) of 10.0 mm to 30.0 mm, in particular of 15.0 mm to 25.0 mm, from the nearest outer tire tread end (1a) in the radial direction. [10] Agricultural tyre according to claim 9, characterized bythat the tread ends (1a) on the outside of the tyre, viewed in the tyre cross-section, are located radially outside the point with the cross-sectional width (B) of the agricultural tyre and have a distance (a1) from this, determined in the radial direction, of in particular 5.0 mm to 25.0 mm. [11] Agricultural tyre according to one of claims 1 to 10, characterized by that the shoulder reinforcement strip (11) runs in the circumferential direction. [12] Agricultural tyre according to one of claims 1 to 10, characterized by that in at least one shoulder area, preferably in each shoulder area, a plurality of shoulder reinforcement strips (11) are installed, which preferably each extend over at least 10% of the tire circumference. [13] Agricultural tyre according to claim 12, characterized by that in each shoulder area a shoulder reinforcement strip (11) is installed radially inside each stud (10a). [14] Pneumatic vehicle tyre according to one of claims 1 to 13, characterized by that the textile cords (11d) of the shoulder reinforcement strip (11) have a diameter of 0.40 mm to 0.60 mm, preferably of 0.45 mm to 0.55 mm. [15] Agricultural tyre according to one of claims 1 to 14, characterized by the textile cords (11d) of the shoulder reinforcement strip (11) are 1440 dtex x 2 polyester cords.

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