Grooved roller, device for embedding steel reinforcement beams in a rubber compound track and uses of this device

Description

[0001] The invention relates to a combination of a grooved roller and reinforcing beams with a flattened cross-section. The invention further relates to a device for embedding steel reinforcing beams in a rubber compound sheet and uses of this device.

[0002] It is generally known and common practice to embed reinforcing elements, such as steel cords or monofilaments, which have a substantially circular cross-section, into a rubber compound web using known devices, ensuring they are parallel to each other and running in a single plane. These devices typically include at least one creel with a plurality of reinforcing elements wound on spools, alignment elements for aligning the reinforcing elements parallel to each other in a single plane and at predetermined intervals, and a grooved roller rotatably mounted about its roller axis, with guide grooves for guiding and transferring the reinforcing elements into the compression gap of a roller calender. The guide grooves have clear spacings that correspond to the predetermined clear spacings of the reinforcing elements in the rubber compound web.The reinforced sheets emerging from the roller calender, which contain embedded reinforcing elements, are used for further processing, particularly in the manufacture of pneumatic vehicle tires of any design, for example as belt plies or carcass inserts. The guide grooves of the known groove rollers have an approximately V-shaped or trough-shaped cross-section.

[0003] US Patent 7,998,298 B2 discloses a calender line for manufacturing a reinforcing layer intended, for example, for a carcass ply of a vehicle tire. The calender line comprises a creel with a wound fabric containing cords and weft threads, a splicing press, a feed unit, a storage device for loop-guided fabric, a centering device, a weft removal device, a roller calender, a cooling device, another storage device for loop-guided reinforcing layer, and a winding device for winding the reinforcing layer. A grooved roller with circumferentially rotating guide grooves and a further grooved roller with guide grooves arranged in pairs with this roller are positioned upstream of the roller calender.The guide grooves have a width that—after the weft threads have been removed from the fabric—allows the remaining cords to be guided, and a depth that is typically smaller than the cord diameter and at least 50% of the cord diameter. This matching of the guide grooves to the cord diameter is intended to ensure good guidance of the cords within the guide grooves, while allowing the cords to move out of the guide grooves easily. The two grooving rollers are each pivotally mounted, enabling the calender line to be operated quickly by performing precisely timed pivoting movements.

[0004] From German patent application TW M563957 U, a device for coating a plurality of adjacent reinforcing elements, preferably made of glass fibers or carbon fibers, is known. The device comprises a creel, a cleaning and drying unit, an alignment unit, a coating unit, a heat press, and a winding unit. During operation of the device, the reinforcing elements pass through the cleaning and drying unit, in which any residues remaining on the reinforcing elements after manufacturing are removed. Subsequently, the reinforcing elements pass through the alignment unit, which comprises two grooved rollers and ensures that the reinforcing elements are guided at defined intervals. The grooved rollers have rectangular, circumferential projections in cross-section and corresponding recesses.The aligned reinforcing bars are guided through the coating unit, where they are statically charged by friction and then passed through a fluidized bed of thermoplastic elastomer powder created by blowing in air. The fluidized bed is intended to ensure a uniform coating of the reinforcing bars, with the coating being particularly uniform compared to conventional dip coating processes. The coated reinforcing bars are then passed through the heat press and subsequently wound onto the winding unit.

[0005] WO 2021 / 028120 A1 discloses a maintenance device for a calender line for embedding steel reinforcing elements in a rubber compound web. The maintenance device includes grooved rollers.

[0006] US Patent 2005 / 048280 A1 discloses a device for manufacturing a reinforcing layer for a belt bandage of a vehicle tire. The device comprises a dipping unit and an alignment unit for aligning the cords in a plane prior to the dipping process, and preferably grooving rollers, wherein, in particular, a first grooving roller and a second grooving roller are provided with guide grooves that are narrower than those of the first grooving roller. By guiding the cords in the guide grooves of the grooving rollers, the cords are guided in a manner that approximates each other with respect to their transport direction.

[0007] Reinforcing layers in pneumatic tires are designed to enhance specific tire properties, reduce tire weight, and, most importantly, lower rolling resistance. Particularly high demands are placed on the reinforcing layers in the belt plies of pneumatic tires, such as, depending on the tire type, favorable tensile strength and flexural stiffness, high fatigue resistance, and high corrosion resistance. Furthermore, these reinforcing layers should contribute to low tire weight, for example, by containing as little rubber material as possible and thus being as thin as possible without compromising their performance.In this respect, reinforcing elements with a flattened, non-circular cross-sectional shape are particularly advantageous, as they help reduce the thickness of the reinforcement layers, which in turn reduces the amount of rubber used and thus the tire weight. For use in belt layers, flattened steel cords, such as those known from KR 10109719 B1, are therefore particularly suitable with regard to the requirements placed upon them. Advantageously, these steel cords should be embedded in a tire belt layer in such a way that their larger cross-sectional dimension runs parallel to the tire axis or is embedded flat within the respective reinforcement layer. It is not possible to achieve the desired orientation of reinforcing elements with a flattened cross-section using conventional groove rollers.

[0008] The invention is based on the objective of providing a combination of the type mentioned above which enables the embedding of cross-sectionally flattened steel reinforcement beams in such a way that these reinforcement beams run parallel or largely parallel to the outer surfaces of the rubber compound sheet with their greatest width.

[0009] The problem is solved according to the invention by a combination of a grooved roller and cross-sectionally flattened reinforcing beams, wherein the grooved roller has a plurality of guide grooves parallel to each other and circumferentially around its circumference for guiding the cross-sectionally flattened reinforcing beams before they enter a roller calender, which reinforcing beams have a first diameter in cross-section and a second diameter perpendicular to this, wherein the second diameter is smaller than the first diameter and both diameters are determined at the points with the greatest widths. wherein the guide grooves each have a U-shaped cross-section with a groove bottom running parallel to the roller axis and two groove walls running perpendicular or largely perpendicular to the roller axis, wherein the groove bottom has a width which corresponds at least to the first diameter of the reinforcing element and is up to 5% larger than it, and wherein the groove walls have a height which is 75% to 90% of the second diameter of the reinforcing element and are inclined outwards perpendicular to the groove bottom or with respect to a perpendicular to the groove bottom at an angle of up to 3°.

[0010] Surprisingly, it has been found that a simple measure, namely the special geometry of the guide grooves of the grooved roller according to the invention, causes the cross-sectionally flattened reinforcing elements guided by the guide grooves to align themselves flat within the grooves, so that they enter the press gap between the two rollers of the roller calender, at least largely, in the desired orientation. The guide grooves ensure a particularly reliable and precise alignment of the flattened reinforcing elements. The groove walls are inclined outwards, meaning that the guide grooves become slightly wider towards their upper opening. This counteracts any tilting of the flattened reinforcing elements.

[0011] In a preferred embodiment of the combination, the width of the groove base of the guide grooves is up to 3% larger than the first diameter of the reinforcing beam.

[0012] Furthermore, it is advantageous to design the guide grooves in which the transitions between the groove walls and the groove base are rounded, particularly with a radius of no more than 1.00 mm. The rounded corner areas at the base of the guide grooves counteract any tilting of the flattened reinforcing elements.

[0013] The invention further relates to a device for embedding steel reinforcement elements in a rubber compound web, wherein this device is provided with at least one creel with a plurality of reinforcement elements wound on coils, with alignment elements for aligning the reinforcement elements parallel to each other in a plane and at predetermined mutual distances, and with a grooved roller rotatably mounted about its roller axis and arranged upstream of a roller calender, wherein the grooved roller is designed according to the invention, therefore according to one or more of claims 1 to 3.

[0014] Furthermore, the invention relates to advantageous uses of the device.

[0015] The use of this device for embedding steel cords with a flattened cross-section into a rubber compound sheet is particularly preferred and advantageous. In particular, steel cords consisting of 2 to 11 steel filaments, more preferably 3 to 9 steel filaments, and more preferably 4 to 6, and more preferably exactly 5, twisted together are embedded in this way. The device according to the invention is therefore preferably used for embedding reinforcing elements in rubber compound sheets that are intended to be particularly lightweight and that also fulfill other requirements, for example, with regard to tensile strength and flexural stiffness, fatigue resistance, and corrosion resistance.

[0016] One particularly advantageous application involves embedding flattened steel cords with several flattened steel filaments, the latter having a larger diameter and, at right angles to it, a smaller diameter. The diameters are determined at the points of greatest width, and the ratio of the smaller diameter to the larger diameter is between 0.80 and 0.98, particularly between 0.85 and 0.98. In this way, steel cord-reinforced load-bearing layers are provided that meet the aforementioned requirements exceptionally well.

[0017] In an alternative use of the device, which has analogous advantageous effects, it is used to embed flattened steel monofilaments in a rubber compound web.

[0018] When reinforcement layers are created for vehicle pneumatic tires, it is advantageous to embed steel cords or steel monofilaments, whose ratio between the first diameter and the second diameter is 1.10 to 3.00, preferably 1.20 to 1.90, in a rubber compound web.

[0019] According to the invention, therefore, the use of the rubber compound sheet produced in a device according to the invention as a belt layer in a belt assembly of a vehicle pneumatic tire, as a carcass of a vehicle pneumatic tire or as a bead reinforcement layer of a vehicle pneumatic tire is particularly advantageous.

[0020] Further features, advantages, and details of the invention will now be described in more detail with reference to the schematic drawing, which illustrates exemplary embodiments. Fig. 1 a schematic representation of a device for manufacturing a rubberized reinforcing layer with steel reinforcing elements for a vehicle pneumatic tire, Fig. 2 a partial section of an axial longitudinal section of a grooved roller, Fig. 3 an enlarged view of detail D e from Fig. 2 , Fig. 4 a cross-section of an exemplary embodiment of a steel cord and Fig. 5 a cross-section of a section of a reinforcement layer of a vehicle tire.

[0021] Layers in vehicle pneumatic tires reinforced with steel reinforcements are particularly belt layers, carcass inserts or bead reinforcement layers in bead areas.

[0022] Fig. 1 Figure 1 shows essential components of a device for rubberizing reinforcing materials 10, arranged sequentially in the processing direction. In the illustrated embodiment, these components include at least a creel 1, alignment elements, which in particular include perforated plates 2, sorting plates 3, guide rollers 4, and a dividing comb 5, as well as a grooved roller 6 rotatably mounted about its roller axis 6a and a roller calender 7. The creel 1 is provided with a plurality of spool holders and spools 1a, onto which reinforcing materials 10 of a matching design and construction are wound. The spool holders arranged on the creel 1 are each equipped with an adjustable thread brake, for example, an electromagnetic one, to ensure the most optimal tension possible on the reinforcing materials 10 during rubberizing.

[0023] The reinforcing elements 10 are either flattened steel cords, which in any design consist of 2 to 11 steel filaments, in particular 3 to 9, or flattened steel monofilaments. The steel cords and the steel monofilaments have an overall non-circular, flat cross-section with a larger diameter D1 (see D1 in Fig. 4 ), and a smaller diameter D2 at a right angle to the one D1 (see D2 in Fig. 4 The diameters D1 and D2 are determined at the points of greatest width. The ratio of D1 to D2 is particularly 1.10 to 3.00, preferably 1.20 to 1.90. The steel filaments of the steel cord and the steel monofilaments exhibit a typical tensile strength of 2,500 N / mm² to 4,500 N / mm², thus the tensile strength is essentially in the range of NT (Normal Tensile) to UT (Ultra Tensile).

[0024] Fig. 4 Figure 1 shows a schematic cross-section of a flattened steel cord 8 with five steel filaments 9. The flattened steel cord 8 is manufactured by twisting five identical, circular steel filaments with a diameter d of 0.10 mm to 0.60 mm, particularly 0.18 mm to 0.45 mm, together, initially producing round, nearly circular steel cords as "original cords". These "original cords" are then deformed, for example by a rolling process, so that at least two steel filaments 9 are locally flattened or deformed, particularly in the area of ​​their mutual contact points, thereby acquiring at least a partially uniformly or unevenly flattened cross-sectional shape (in the schematic figure 1). Fig. 4 (Uneven cross-sectional shapes are not shown), whereby the steel cord 8 also acquires an overall flattened cross-sectional shape. Due to the twisting of the steel filaments 9, the steel filaments 9 are deformed differently when viewed in different cross-sections along the length of the steel cord 8; some may not be deformed and then locally retain their originally circular cross-section, as shown in Fig. 4 as shown by the steel filament 9 located on the far left.

[0025] In the rolled, flattened cross-sectional form of the steel cord 8, the steel filaments 9, flattened by deformation, have a larger diameter d1 transverse to the deformation direction and a smaller diameter d2 at right angles to it. The diameters d1 and d2 are also determined at the points of greatest width. The ratio of d2 to d1 is particularly 0.80 to 0.98, preferably 0.85 to 0.98. In the example of the steel cord 8 shown, the ratio of d1 to d2 is also on the order of 1.6.

[0026] Flattened steel monofilaments, for example, have an oval, elliptical, or elliptical cross-sectional shape; their larger diameter is 0.10 mm to 1.50 mm, their smaller diameter 0.10 mm to 1.00 mm, with the ratio of the larger diameter to the smaller diameter being 1.10 to 3.00, particularly 1.20 to 1.90. These diameters are also determined at the points of greatest width.

[0027] How Fig. 1 As shown, the reinforcing elements 10 – flattened steel cords or flattened steel monofilaments in any orientation relative to each other – unwound from the spools 1a of the spool creel 1 pass through holes in the perforated plates 2, are then guided through the sorting plates 3 and over several guide rollers 4, and are thereby aligned parallel to each other and running in one plane. The reinforcing elements 10 are subsequently threaded individually between the lamellae of a dividing comb 5 in a known manner, whereby the desired mutual spacing of the reinforcing elements 10 is set in the dividing comb 5. The set of reinforcing elements 10 then runs in guide grooves 11 ( Fig. 2 ) of the groove roller 6, each reinforcing element 10 in a guide groove 11, wherein the mutual clear distance a of the guide grooves 11 ( Fig. 2 ) on the outer surface of the groove roller 6 corresponds to the distance between the reinforcing elements 10 defined by the thread pitch on the dividing comb 5. The guide grooves 11 run around the circumference of the groove roller 6 and parallel to each other. The specific design of the guide grooves 11 is described below with reference to the Fig. 3 explained in more detail.

[0028] From the guide grooves 11 of the groove roller 6, the sheet of reinforcing material 10 runs into the compression gap between two calender rollers 7a of the roller calender 7. A calendered rubber compound 12 is fed into the compression gap from both above and below, so that the reinforcing material 10 is embedded in the rubber compound parallel to each other. The rubber compound sheet 13 with the reinforcing material 10 embedded in this way leaves the compression gap and is fed into further processing during tire construction.

[0029] In order to ensure that all reinforcing elements 10 can be embedded lying flat, and therefore with their larger dimension, the diameter D 1, running as parallel as possible to the outer surfaces of the rubber compound sheet 13, the guide grooves 11 have a special U-shaped cross-section. According to Fig. 2 und Fig. 3 Each guide groove 11 of two is oriented towards the roller axis 6a ( Fig. 1 ) vertically extending groove walls 11a and a groove bottom 11b running parallel to the roller axis 6a. The width b ( Fig. 3 ) of the groove base 11b is connected to the diameter D 1 ( Fig. 4 ) of the respective load-bearing element 10 (in Fig 4 : steel cord 8) adapted by the width b of the groove base 11b being at least equal to the diameter D 1 and being up to 5% larger, in particular up to 3% larger, than this. The height h ( Fig. 3 ) the groove walls 11a is connected to the diameter D 2 ( Fig. 4 ) of the respective load-bearing element 10 (in Fig. 4 : steel cord 8) adapted, wherein the height h corresponds to 50% to 90%, preferably up to 75%, of the diameter D 2. The transitions between the groove walls 11b and the groove bottom 11a are preferably rounded with a radius of a maximum of 1.0 mm. The flattened reinforcing elements 10, entering the guide grooves 11 in any orientation and under low tension, align themselves flat in the guide grooves 11 due to the geometry of the guide grooves 11, so that they enter the press gap between the two calender rolls 7a of the roll calender 7 at least largely in the orientation mentioned above.

[0030] Fig. 5 shows a cross-section through a section of a reinforcement layer 14, for example a raw belt layer, for a vehicle pneumatic tire with embedded steel cords 8 according to Fig. 4 The mutual clear distance a of the steel cords 8 corresponds to the clear distance a between adjacent guide grooves 11 of the groove roller 6.

[0031] With such embedded reinforcement layers 10, the thickness of reinforcement layers in vehicle pneumatic tires can be significantly reduced compared to comparable, circular in cross-section reinforcement layers, thus advantageously reducing the weight of the tire. Bezugsziffernliste

[0032] 1 Spool creel 1a Spool 2 Perforated plate 3 Sorting plate 4 Guide roller 5 Dividing comb 6 Grooving roller 6a Roller axle 7 Roller calender 7a Calender rollers 8 Steel cord 9 Steel filament 10 Reinforcing element 11 Guide groove 11a Groove wall 11b Groove bottom 12 Rubber compound 13 Rubber compound web 14 Reinforcing layer a Spacing b Width of groove bottom h Height of groove wall D1, D2 Diameter d1, d2 Diameter De Detail

Claims

1. Combination of a grooved roller (6) and strength members (10) of flattened cross section, wherein the grooved roller (6) has a multiplicity of guide grooves (11) which run parallel to one another and in encircling fashion over the circumference of said grooved roller and which serve for guiding the strength members (10) of flattened cross section before they enter a roller calender (7), which strength members (10) have, in cross section, a first diameter (D1) and, perpendicular thereto, a second diameter (D2), wherein the second diameter (D2) is smaller than the first diameter (D1), and the two diameters (D1, D2) are each determined at the points with the greatest widths, wherein the guide grooves (11) each have a U-shaped cross section with a groove base (11b) extending parallel to the roller axis (6a) and with two groove walls (11a) extending perpendicularly or substantially perpendicularly to the roller axis (6a), wherein the groove base (11b) has a width (b) which at least corresponds to, and is up to 5% greater than, the first diameter (D1) of the strength member (10), and wherein the groove walls (11a) have a height (h) which is 75% to 90% of the second diameter (D2) of the strength member (10), and extend perpendicular to the groove base (11b) or with an outward inclination at an angle of up to 3° in relation to a perpendicular to the groove base (11b).

2. Combination according to Claim 1, characterized in that the width (b) of the groove base (11b) is up to 3% greater than the first diameter (D1) of the strength member (10).

3. Combination according to Claim 1 or 2, characterized in that the transitions between the groove walls (11a) and the groove base (11b) are rounded, in particular with a radius of at most 1.0 mm.

4. Device for embedding steel strength members (10) into a rubber mixture web (13), comprising at least one creel (1) having a multiplicity of strength members (10) wound up on spools (1a), comprising aligning elements for aligning the strength members (10) in parallel in a plane at predefined distances (a) from one another, and comprising a grooved roller (6), which is mounted so as to be able to rotate about its roller axis (6a) and is upstream of a roller calender, wherein the grooved roller (6) and the strength member are configured according to one or more of Claims 1 to 3.

5. Use of the device according to Claim 4 for embedding steel cords (8) of flattened cross section into a rubber mixture web (13).

6. Use according to Claim 5 for embedding flattened steel cords (8) which consist of 2 to 11 steel filaments (9), in particular 3 to 9 steel filaments (9).

7. Use according to Claim 6 for embedding flattened steel cords (8) which consist of 4 to 6 steel filaments (9) twisted together.

8. Use according to Claim 6 or 7 for embedding flattened steel cords (8) which consist of 5 intertwined steel filaments (9).

9. Use according to one of Claims 5 to 8 for embedding flattened steel cords (8) comprising flattened steel filaments having a larger diameter (d1) and, at right angles thereto, a smaller diameter (d2), wherein the diameters (d1, d2) are determined at the points with the greatest widths.

10. Use according to Claim 9 for embedding flattened steel cords (8) comprising flattened steel filaments (9), for which the ratio of the smaller diameter (d2) to the larger diameter (d1) is 0.80 to 0.98, in particular 0.85 to 0.98.

11. Use of the device according to Claim 4 for embedding flattened, non-circular steel monofilaments into a rubber mixture web (13).

12. Use of the device according to one of Claims 4 to 9 for embedding flattened steel cords (8) or steel monofilaments of which the ratio between the first diameter (D1) and the second diameter (D2) is 1.10 to 3.00, preferably 1.20 to 1.90.

13. Use of the rubber mixture web produced in a device according to Claim 4 as belt ply in a belt assembly of a pneumatic vehicle tyre, as carcass for a pneumatic vehicle tyre, or as bead reinforcement ply for a pneumatic vehicle tyre.