EP1219746A1 - Stahlseil zur Verstärkung eines Fahrzeugreifens - Google Patents

Stahlseil zur Verstärkung eines Fahrzeugreifens Download PDF

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Publication number
EP1219746A1
EP1219746A1 EP00830852A EP00830852A EP1219746A1 EP 1219746 A1 EP1219746 A1 EP 1219746A1 EP 00830852 A EP00830852 A EP 00830852A EP 00830852 A EP00830852 A EP 00830852A EP 1219746 A1 EP1219746 A1 EP 1219746A1
Authority
EP
European Patent Office
Prior art keywords
threads
cord
cords
core
strand
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP00830852A
Other languages
English (en)
French (fr)
Inventor
Omero Noferi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Pirelli and C SpA
Pirelli Tyre SpA
Original Assignee
Pirelli Pneumatici SpA
Pirelli SpA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Pirelli Pneumatici SpA, Pirelli SpA filed Critical Pirelli Pneumatici SpA
Priority to EP00830852A priority Critical patent/EP1219746A1/de
Priority to BR0106531A priority patent/BR0106531A/pt
Priority to US10/026,882 priority patent/US20020134478A1/en
Publication of EP1219746A1 publication Critical patent/EP1219746A1/de
Withdrawn legal-status Critical Current

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Classifications

    • D—TEXTILES; PAPER
    • D07—ROPES; CABLES OTHER THAN ELECTRIC
    • D07B—ROPES OR CABLES IN GENERAL
    • D07B1/00—Constructional features of ropes or cables
    • D07B1/06—Ropes or cables built-up from metal wires, e.g. of section wires around a hemp core
    • D07B1/0606—Reinforcing cords for rubber or plastic articles
    • D07B1/062—Reinforcing cords for rubber or plastic articles the reinforcing cords being characterised by the strand configuration
    • D07B1/0633—Reinforcing cords for rubber or plastic articles the reinforcing cords being characterised by the strand configuration having a multiple-layer configuration
    • D—TEXTILES; PAPER
    • D07—ROPES; CABLES OTHER THAN ELECTRIC
    • D07B—ROPES OR CABLES IN GENERAL
    • D07B1/00—Constructional features of ropes or cables
    • D07B1/06—Ropes or cables built-up from metal wires, e.g. of section wires around a hemp core
    • D07B1/0606—Reinforcing cords for rubber or plastic articles
    • D07B1/062—Reinforcing cords for rubber or plastic articles the reinforcing cords being characterised by the strand configuration
    • D07B1/0626—Reinforcing cords for rubber or plastic articles the reinforcing cords being characterised by the strand configuration the reinforcing cords consisting of three core wires or filaments and at least one layer of outer wires or filaments, i.e. a 3+N configuration
    • D—TEXTILES; PAPER
    • D07—ROPES; CABLES OTHER THAN ELECTRIC
    • D07B—ROPES OR CABLES IN GENERAL
    • D07B2201/00—Ropes or cables
    • D07B2201/10—Rope or cable structures
    • D07B2201/104—Rope or cable structures twisted
    • D07B2201/1052—Rope or cable structures twisted using lang lay, i.e. the wires or filaments being inclined relative to the rope axis
    • D—TEXTILES; PAPER
    • D07—ROPES; CABLES OTHER THAN ELECTRIC
    • D07B—ROPES OR CABLES IN GENERAL
    • D07B2201/00—Ropes or cables
    • D07B2201/20—Rope or cable components
    • D07B2201/2015—Strands
    • D07B2201/2023—Strands with core
    • D—TEXTILES; PAPER
    • D07—ROPES; CABLES OTHER THAN ELECTRIC
    • D07B—ROPES OR CABLES IN GENERAL
    • D07B2201/00—Ropes or cables
    • D07B2201/20—Rope or cable components
    • D07B2201/2015—Strands
    • D07B2201/2024—Strands twisted
    • D07B2201/2027—Compact winding
    • D07B2201/2028—Compact winding having the same lay direction and lay pitch
    • D—TEXTILES; PAPER
    • D07—ROPES; CABLES OTHER THAN ELECTRIC
    • D07B—ROPES OR CABLES IN GENERAL
    • D07B2201/00—Ropes or cables
    • D07B2201/20—Rope or cable components
    • D07B2201/2015—Strands
    • D07B2201/2024—Strands twisted
    • D07B2201/2029—Open winding
    • D07B2201/203—Cylinder winding, i.e. S/Z or Z/S

Definitions

  • the present invention relates to a cord for a tyre for a vehicle and a tyre provided with said cord.
  • vehicle tyres which have a carcass provided with a metallic reinforcement including cords, each cord consisting of a metallic core thread and two concentric shells of metallic threads arranged around the core thread.
  • the shell threads are wound helicoidally in the same direction (i.e., they have a so-called “Lang Lay” type winding), in a "S" (right-handed) or "Z” (left-handed) configuration.
  • the cords of the type described are very compact and their manufacturing costs are low. However, they have the disadvantage of having low resistance to fatigue and being subject to breaking and migration (displacement) of the core thread.
  • the cords of the tyre carcass are subjected to alternating bending stresses, particularly on the sidewalls, when the tyre enters and leaves the contact area with the ground (the footprint). In the case of a carcass having cords with core thread, these alternating bending stresses can easily lead to the breakage of the core thread.
  • the core thread has a low degree of attachment to the innermost shell of threads. Therefore, during the production of the tyre, and also when it is in use, in other words during the running of the vehicle, the core thread may slip longitudinally within the radially innermost shell of threads, with consequent migration of the core thread beyond the ends of the cord.
  • the object of the present invention is to eliminate the disadvantages of the known cords.
  • the invention in a first aspect, relates to a cord for a tyre including a strand of metallic core threads and at least two shells of metallic threads arranged around said strand, said threads of said strand and of said shells being wound helicoidally, characterized in that said threads of said strand and of said shells have a "Lang Lay" type winding.
  • the number of said threads of said strand is in the range from 2 to 5. In a preferred embodiment of the invention, the number of threads in said strand is three.
  • the number of threads of said radially inner shell is in the range from 5 to 9. In one embodiment, the number of said shell threads is 6.
  • the number of threads of said radially outer shell is in the range from 10 to 15. In one embodiment, the number of said shell threads is 12.
  • said threads of said core strand and of said shells have a "S" winding.
  • said threads of said core strand and of said shells have a "Z" winding.
  • the invention in a second aspect, relates to a tyre for a motor vehicle, having a carcass including reinforcing cords, each of said cords including a strand of metallic core threads and at least two shells of metallic threads arranged around said core strand, said threads of said core strand and of said shells being wound helicoidally, characterized in that said threads of said core strand and of said shells have a "Lang Lay" type winding.
  • the cord according to the invention is particularly advantageous. This is because it has a greater tensile strength and lower bending rigidity than conventional cords with core thread, as well as it has a greater resistance to fretting than conventional cords provided with core strand.
  • Figs. 1 and 2 show a preferred embodiment of a cord 1 for a tyre, made according to the invention.
  • Said cord 1 comprises a core strand 2, an inner shell 3 and an outer shell 4.
  • the core strand 2 consists of three metallic threads 5 wound together helicoidally with a "S" winding;
  • the inner shell 3 consists of six metallic threads 6 wound helicoidally in a "S" winding around the threads of the core strand, and
  • the outer shell 4 consists of twelve metallic threads 7 wound helicoidally in a "S” winding around the threads of the inner shell.
  • the direction of winding of the threads of the core strand 2, and of the threads of both shells 3 and 4 is the same ("Lang Lay” type winding) in the cord 1 according to the invention.
  • the winding of the threads is of the "S" type.
  • the winding pitch is 14 mm.
  • the diameter of the aforesaid threads 5, 6 and 7 can vary from 0.10 mm to 0.40 mm, and does not have to be identical for all the threads of the cord.
  • the diameter of the strand threads is smaller than that of the threads of the two concentric shells.
  • the diameter of the strand threads is in the range from 0.10 mm to 0.15 mm, while that of the shell threads is in the range from 0.20 mm to 0.30 mm, the difference between said values being at least 0.05 mm, and preferably at least 0.10 mm.
  • the diameter of the threads and the number of threads in the strand and in the shells are interdependent, since they are related to the requirement of having compact cords, of small diameter, which at the same time are highly penetrable by the rubberizing material.
  • a cord in which the threads of the core strand 2 and the threads of both shells 3 and 4 have a "Z" winding has a performance similar to that of the corresponding cord with the "S" winding.
  • Figs. 3 and 4 show a conventional cord 11 for a tyre, including a core thread 12, an inner shell 13 and an outer shell 14.
  • the inner shell 13 consists of six metallic threads 16 wound helicoidally in a "S" winding around the core thread 12
  • the outer shell 14 consists of twelve metallic threads 17 wound helicoidally in a "S" winding around the threads of the inner shell.
  • Figs. 5 and 6 show a conventional cord 21 for a tyre, including a core strand 22, an inner shell 23 and an outer shell 24.
  • the strand 22 consists of three metallic threads 25 wound together helicoidally in a "S" winding; the inner shell 23 consists of nine metallic threads 26 wound helicoidally in a "S” winding around the strand threads 22, and the outer shell 24 consists of fifteen metallic threads 27 wound helicoidally in a "Z" winding around the threads of the inner shell.
  • a small thread (“wrap") 28 is wound around the threads 27 of the outer shell 24. Therefore, in the cord 21 the threads 26 of the inner shell 23 and the threads 27 of the outer shell 24 are wound in opposite directions.
  • Fig. 8 shows a tyre 30 having a carcass 31 provided with reinforcing cords 1 according to the invention, as shown in Figs. 1 and 2.
  • the Applicant has conducted a number of tests, comparing the performance of cords made according to the invention with that of conventional cords. The results of the tests are shown below.
  • the structure of the cords used in said set of tests is shown in Table 1.
  • the three conventional cords, identified by the numbers 1, 2 and 3, have a 1+6+12 configuration, while the three cords according to the invention, identified by the numbers 4, 5 and 6, have a 3+6+12 configuration.
  • the test consisting in winding a cord with a length of 1000 mm over a 100 mm diameter pulley, with no traction or torsion applied to the threads, and measuring the tensile and bending forces acting in the threads, was simulated in advance on a computer.
  • sigma 1 is the tension acting in the core thread of cords 1-3 or in the threads of the core strand in cords 4-6
  • sigma 2 and sigma 3 are, respectively, the tensions acting in the threads of the inner shell and in the threads of the outer shell of the aforesaid cords
  • Mb is the bending moment
  • A* is the bending rigidity of the cords.
  • the test consisted in subjecting the cord (having a length of 1000 mm) to an applied bending moment, of approximately 10 N mm, in the absence of traction and torsion, and measuring the tensile forces acting in the threads and the radius of curvature assumed by the cord. This radius of curvature corresponds to the diameter of the pulley which would cause a bending moment essentially equal to the applied bending moment to appear in the cord wound on this pulley under the same conditions.
  • the test was simulated in advance on a computer.
  • cords 4-6 according to the invention could be wound on pulleys whose diameter Dp was smaller than that of pulleys on which the corresponding conventional cords 1-3 could be wound.
  • cords 4-6 according to the invention were shown to be more flexible than the conventional cords 1-3.
  • the test consisted in the application of a tension of 100 N to the cord while the torque and the bending moment at its ends were kept at zero.
  • the test was simulated in advance on a computer.
  • test was carried out by applying a tensile force to the cord and leaving it free to rotate about its own axis to dissipate the torque generated by said tension.
  • the test consisted in the application of a tension of 100 N to the cord while the bending moment at its ends was kept at zero and the cord was prevented from rotating about its own axis.
  • the test was simulated in advance on a computer.
  • Tests 1-4 described above showed that the cords according to the invention had half of the tensions due to bending, as well as a lower bending rigidity (in other words a higher torque) with respect to the conventional cords which were considered.
  • the test was conducted by comparing the cord 5 (Invention), the conventional cord 2 (Comparative 1) and a conventional cord with a core strand (of the type illustrated in Figs. 5 and 6) having the following structure: 3+9+15x0.22+0.15 (Comparative 2).
  • the specimens were formed by preparing strips of rubberized and vulcanized fabric comprising a predetermined number (generally from 3 to 5) of cords of the above types.
  • Each strip of fabric was subjected to a fatigue test consisting of a series of cyclical bendings (1500 kC in the case in question), caused by moving each fabric strip alternately in two directions around a roller of suitable dimensions (having a diameter of 32 mm in the case in question), to which a suitable pre-loading was applied (this pre-loading being chosen appropriately in relation to the dimensions of the reinforcing cords, and being 450 N in the case in question).
  • the degree of wear of the individual threads was measured according to the scale of wear shown in Fig. 7.
  • the degree of wear found in the individual threads of the cords is shown below in Table VI, in which each individual value indicates the degree of wear (measured according to the scale in Fig. 7) in one area of the thread, while the sum of a plurality of values indicates the total degree of wear in two or more areas of a single thread.
  • the value "2+1+2" relating to thread 6 of the inner shell of the "Comparative 1" cord indicates that said thread has three different areas of wear in the same cross section (said areas being identifiable in the figures as flattenings of the circular section of each thread), namely two areas with a degree of wear equal to 2 and one area with a degree of wear equal to 1.
  • the cord according to the invention had undergone a very low degree of wear due to fretting, this degree of wear being less than half of the wear of the Comparative 1 cord and about 15 times less than the wear of the Comparative 2 cord.
  • Fig. 9 is a photographic reproduction of a cross section of the cord according to the invention in the initial state.
  • Figs. 10 and 11 are photographic reproductions of two cross sections of the cord according to the invention in the final state, after 1500 kilocycles (kC), where the cross sections have been taken within the same pitch.
  • Fig. 12 is a photographic reproduction of a cross section of the Comparative 1 cord in the initial state.
  • Figs. 13 and 14 are photographic reproductions of two cross sections of the Comparative 1 cord in the final state, after 1500 kilocycles (kC), where the cross sections are close to each other, within the same pitch.
  • kC kilocycles
  • Fig. 15 is a photographic reproduction of a cross section of the Comparative 2 cord in the initial state.
  • Figs. 16 and 17 are photographic reproductions of two cross sections of the Comparative 2 cord in the final state, after 1500 kilocycles (kC), where the cross sections are close to each other, within the same pitch.
  • kC kilocycles

Landscapes

  • Ropes Or Cables (AREA)
  • Yarns And Mechanical Finishing Of Yarns Or Ropes (AREA)
EP00830852A 2000-12-28 2000-12-28 Stahlseil zur Verstärkung eines Fahrzeugreifens Withdrawn EP1219746A1 (de)

Priority Applications (3)

Application Number Priority Date Filing Date Title
EP00830852A EP1219746A1 (de) 2000-12-28 2000-12-28 Stahlseil zur Verstärkung eines Fahrzeugreifens
BR0106531A BR0106531A (pt) 2000-12-28 2001-12-27 Cordão e, pneu para um veìculo motorizado
US10/026,882 US20020134478A1 (en) 2000-12-28 2001-12-27 Cord for a vehicle tyre and tyre provided with said cord

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP00830852A EP1219746A1 (de) 2000-12-28 2000-12-28 Stahlseil zur Verstärkung eines Fahrzeugreifens

Publications (1)

Publication Number Publication Date
EP1219746A1 true EP1219746A1 (de) 2002-07-03

Family

ID=8175607

Family Applications (1)

Application Number Title Priority Date Filing Date
EP00830852A Withdrawn EP1219746A1 (de) 2000-12-28 2000-12-28 Stahlseil zur Verstärkung eines Fahrzeugreifens

Country Status (2)

Country Link
EP (1) EP1219746A1 (de)
BR (1) BR0106531A (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111648148A (zh) * 2020-05-11 2020-09-11 贵州钢绳股份有限公司 一种Φ50mm高级建筑物用不锈钢单股钢丝绳
US11400766B2 (en) * 2017-11-27 2022-08-02 Jiangsu Xingda Steel Tyre Cord Co., Ltd. Cable bead and tire

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3352098A (en) * 1964-12-23 1967-11-14 American Chain & Cable Co Multi-element wire line having compacted strands
EP0627520A1 (de) * 1993-06-02 1994-12-07 N.V. Bekaert S.A. Kompaktes Stahlseil ohne Umhüllungselement
EP0709236A1 (de) * 1994-10-28 1996-05-01 Sumitomo Rubber Industries Limited Reifenkord

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3352098A (en) * 1964-12-23 1967-11-14 American Chain & Cable Co Multi-element wire line having compacted strands
EP0627520A1 (de) * 1993-06-02 1994-12-07 N.V. Bekaert S.A. Kompaktes Stahlseil ohne Umhüllungselement
EP0709236A1 (de) * 1994-10-28 1996-05-01 Sumitomo Rubber Industries Limited Reifenkord

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
31618: "Steel cord construction", RESEARCH DISCLOSURE, no. 316, August 1990 (1990-08-01), KENNETH MASON PUBLICATIONS, HAMPSHIRE, GB, XP000140924, ISSN: 0374-4353 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11400766B2 (en) * 2017-11-27 2022-08-02 Jiangsu Xingda Steel Tyre Cord Co., Ltd. Cable bead and tire
CN111648148A (zh) * 2020-05-11 2020-09-11 贵州钢绳股份有限公司 一种Φ50mm高级建筑物用不锈钢单股钢丝绳

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Publication number Publication date
BR0106531A (pt) 2002-10-01

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