A cord rubberized in situ (C). Internal layer of the cord (CT1) comprises N1 internal thread(s). External layer of the cord (CT3) comprises N3 external threads wound helically around the internal layer of the cord. Rubber composition (20) is positioned between the internal layer of the cord and the external layer of the cord, and comprises a compound of formula (I) or a salt of this compound:

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in which: each R1, R2 and R3 group represents, independently of one another, an alkylene, arylene, arylalkylene, alkylarylene or cycloalkylene group, each X.sub.1 and X.sub.2 group represents, independently of each other, COOH, CONHOH, SOOH, PO(OR)(R) or PO(OR)(OR) with R and R representing, independently of each other, hydrogen or an alkyl group, and X.sub.3 comprises at least one COOH, CONHOH, SOOH, PO(OR)(R) or PO(OR)(OR) group with R and R representing, independently of each other, hydrogen or an alkyl group.

Disclosed is a tire-reinforcing steel cord for a radial tire. The tire-reinforcing steel cord has a double layer structure including a first-layer core and a second-layer core provided on the surface of the first-layer core. The first-layer core has an elliptical or rectangular cross section. The tire-reinforcing steel cord can improve processability, fatigue characteristics, and rolling resistance performance of a tire, resulting in improved fuel efficiency. A radial tire using the tire-reinforcing steel cord is also disclosed.

A multi-strand cord (50) having a 1N structure comprises a single layer (52) of N strands (54) wound in a helix about a main axis (A), each strand (54) having one layer (56) of metal filaments (F1) and comprising M>1 metal filaments wound in a helix about an axis (B). The cord (50) has a total elongation At>8.10% and the energy-at-break indicator Er of the cord (50), defined by Er=.sub.0.sup.At(Ai)dAi where (Ai) is the tensile stress in MPa measured at the elongation Ai and dAi is the elongation such that Er is strictly greater than 52 MJ/m.sup.3.

The method makes it possible to manufacture an assembly (A) comprising a layer (C) of metal filamentary elements (14) wound in a helix. The method comprises a step (100) of supplying a temporary assembly (22) comprising a layer (13) of M>1 metal filamentary elements (14) and a temporary centre (16), and a step (110) of separating the temporary assembly (22) between a first split assembly (25), a second split assembly (27) and the temporary centre (16). The method comprises a step (140) of reassembling the first split assembly (25) with the second split assembly (27) so as to form the layer (C) of the assembly (A).

A steel cord, a production method thereof, and a tire are provided. The steel cord is formed by twisting multiple steel wires, at least one of the steel wires is deformable to allow the cord to have an irregular surface morphology, and the irregular surface morphology is located at one or two symmetrical identical positions in an axial direction of the cord, such that a cross-section of the cord has a long axis and a short axis unequal to the long axis. The irregular surface morphology of the cord designed in the application is located at identical positions in the axial direction of the cord and destroys the uniform support state of steel wires in the circumferential direction of the cord, and it is difficult for the cord to maintain its original circular cross-section form in the subsequent stress relieving process, such that a flat cord can be produced.

The invention relates to a metallic reinforcing cord for tyres for vehicle wheels, comprising at least two metallic wires twisted together with a predetermined twisting pitch, wherein the metallic reinforcing cord has a part load elongation greater than 3%, preferably greater than 3.5%.

The invention relates to a process for manufacturing a metallic reinforcing cord (10) for tyres for vehicle wheels. The process comprises providing at least one elongated element (15) comprising at least one metallic wire (11) twisted together with at least one textile yarn (20) and removing said at least one textile yarn (20) from said at least one elongated element (15) to form the aforementioned metallic reinforcing cord (10). Such a metallic reinforcing cord (10) has a helical geometry, consisting only of said at least one metallic wire (11) that extends along a helical path.

The invention also relates to an apparatus (1) for manufacturing the aforementioned metallic reinforcing cord (10).

The invention provides a steel cord with a construction of n1, n is the number of the steel filaments of the steel cord, the steel cord has an elongation at 2.5N-50N of less than 1.2% and a twist pitch of greater than 16 mm, each of the steel filaments has a form of helical wave with a wave length L expressed in mm and a wave height H expressed in mm when being unravelled from said steel cord, L is greater than 16 mm, each of the steel filaments has a space volume Vs satisfying that, Vs=LH.sup.2/4, and Vs>20 mm.sup.3. The invention steel cord is beneficial for the stress distribution.

The invention relates to a metallic reinforcing cord (10) for tyres for vehicle wheels, comprising from two to ten metallic wires (11) twisted together with a twisting pitch (P) and each having a predetermined diameter. In at least some cross sections of the metallic reinforcing cord (10), at least two of said metallic wires (11) are arranged to a minimum mutual distance greater than, or equal to, 2.5 times the predetermined diameter.

Provided is a method for producing a layered steel cord and belongs to the technical field of steel cord production. The method includes: prestressing some of steel filaments in each layer other than a core wire to obtain prestressed steel filaments; and arranging conventional steel filaments and the prestressed steel filaments in each layer alternately in a stranding machine and performing twisting to obtain the layered steel cord. In the prior art, during the twisting process of a steel cord, due to the residual stress of a steel filament itself and the fluctuation of the tension during the unwinding process, a layered steel cord has a problem of a large interlayer residual stress. The methods controls the stress distribution state of a twisted layered steel cord by prestressing steel filaments, and avoids unflatness of a cord fabric during calendering and warping during cutting in the production process of tires.