Adapter For a Rolling Assembly And Rolling Assembly Comprising Same

Abstract

Adapter for rolling assembly comprising tire and rim to provide the connection therebetween. The adapter has axially inner end with inner reinforcing element, axially outer end with outer reinforcing element, and a body. The outer reinforcing element, axially outside of bearing face (21), is a bead wire made of three layers (23, 24, 25) of metal threads and concentric. First layer (23) includes metal thread of diameter D1, 0.8D15 mm, second layer (24) has metal thread of diameter D2, D21.4D1, and wound in a helix at angle A2, 2A210, and third layer (25) has metal thread of diameter D3 and wound in a helix around second layer (24) at angle A3, 2A310, and of opposite sign to A2.

Claims

1. An adapter for a rolling assembly having an axis of rotation, the rolling assembly comprising a tire having two beads, a rim having two rim bead seats, for each bead, the said adapter providing the connection between the bead and the rim, the said adapter comprising: an axially inner end comprising an inner reinforcing element and adapted to be mounted on a rim bead seat; an axially outer end comprising an outer reinforcing element and adapted to come into contact, via a substantially radial axially inner face, or bearing face, with a bead; a body connecting the axially outer end to the axially inner end so as to form a single piece, and comprising at least one main reinforcement providing the connection between the outer reinforcing element and the inner reinforcing element, and comprising a substantially axial adapter seat adapted to come into contact with a bead, wherein the outer reinforcing element is wholly axially on the outside of the bearing face, wherein the outer reinforcing element is an annular structure, referred to as a bead wire, having a mean line and comprised of a stack of at least three layers comprised of metal threads and concentric with respect to the mean line, wherein a first layer or core comprises at least one metal thread having a diameter D1 at least equal to 0.8 mm and at most equal to 5 mm, wherein a second layer is comprised of a metal thread having a diameter D2 at most equal to 1.4 times the diameter D1 and wound in a helix around the core, forming, with the mean line of the bead wire, an angle A2 at least equal to 2 and at most equal to 10, and wherein a third layer is comprised of a metal thread having a diameter D3 wound in a helix around the second layer, forming, with the mean line of the bead wire, an angle A3 at least equal to 2 and at most equal to 10, and of opposite sign to that of the angle A2.

2. The adapter according to claim 1, wherein the core of the bead wire is comprised of a single metal thread.

3. The adapter according to claim 1, wherein the third layer is comprised of a metal thread having a diameter D3 equal to the diameter D2.

4. The adapter according to claim 1, wherein the angles A2 and A3 formed respectively by the metal threads that comprise the second and third layers of the bead wire are at least equal to 3 and at most equal to 8.

5. The adapter according to claim 1, with the second layer of the bead wire comprising, in any radial section, N2 sections of individual threads of diameter D2, wherein the number N2 of sections of individual threads of diameter D2 is at least equal to 5.

6. The adapter according to claim 1, with the second layer of the bead wire comprising, in any radial section, N2 sections of individual threads of diameter D2, and with the third layer of the bead wire comprising, in any radial section, N3 sections of individual threads of diameter D3, wherein the number N3 of sections of individual threads of diameter D3 is at least equal to the number N2+6 of sections of individual threads of diameter D2.

7. The adapter according to claim 1, wherein the diameter D1 of the metal thread that comprises the core of the bead wire is at least equal to 1.2 mm and at most equal to 4.5 mm.

8. The adapter according to claim 1, with the metal threads of which the first, second and third layers of the bead wire are comprised of steel and having a breaking strength Rm, wherein the breaking strength Rm of a steel thread is at least equal to 1000 MPa and at most equal to 3000 MPa.

9. The adapter according to claim 1, with the bead wire having a circular radial cross section of diameter D.sub.S, wherein the diameter D.sub.S of the circular radial cross section of the bead wire is at least equal to 4 mm and at most equal to 25 mm.

10. The adapter according to claim 1, wherein the body comprises an annular seat reinforcer radially on the inside of the adapter seat.

11. The adapter according to claim 10, wherein the annular seat reinforcer has a compression modulus greater than or equal to 1 GPa.

12. The adapter according to claim 10, wherein the annular seat reinforcer comprises a reinforcing element coated in a polymer material.

13. The adapter according to claim 12, wherein the reinforcing element of the annular seat reinforcer comprises a metallic material such as steel.

14. The adapter according to claim 12, wherein the reinforcing element of the annular seat reinforcer comprises glass fibres coated in a polymer material.

15. The adapter according to claim 1, wherein the main reinforcement of the body comprises a radial superposition of at least two layers of reinforcers, said reinforcers being mutually parallel within one and the same layer and crossed with one another from one layer to the next, and wherein each of the layers of the main reinforcement of the body comprises reinforcers which make, with a circumferential direction of the tire, an angle at least equal to 30, and coated with a polymer material having an elastic modulus at 10% elongation at most equal to 70 MPa.

16. A rolling assembly comprising, for each bead of a tire, an adapter according to claim 1.

17. The adapter according to claim 1, with the metal threads of which the first, second and third layers of the bead wire are comprised of steel and having a breaking strength Rm, wherein the breaking strength Rm of a steel thread is at least equal to 1400 MPa and at most equal to 2800 MPa.

18. The adapter according to claim 1, with the bead wire having a circular radial cross section of diameter D.sub.S, wherein the diameter D.sub.S of the circular radial cross section of the bead wire is at least equal to 6 mm and at most equal to 21 mm.

19. The adapter according to claim 10, wherein the annular seat reinforcer has a compression modulus greater than 10 GPa.

Description

[0067] The invention is described with reference to the following FIGS. 1 to 3, which are schematic and not necessarily drawn to scale:

[0068] FIG. 1: a radial section of a non-mounted adapter, according to a first alternative form of the invention with an annular seat reinforcer;

[0069] FIG. 2: a radial section of a non-mounted adapter, according to a second alternative form of the invention without an annular seat reinforcer;

[0070] FIG. 3: a radial section of a rolling assembly, comprising two adapters according to the second alternative form of the invention without an annular seat reinforcer.

[0071] FIG. 1 depicts an adapter, not mounted on a rim, according to a first alternative form of the invention with an annular seat reinforcer. This adapter comprises an axially outer end 9 comprising an outer reinforcing element 15, an axially inner end 10 comprising an inner reinforcing element 16, and a body 11 comprising a main reinforcement 17. The main reinforcement 17 is made up of a single reinforcing layer which is wound respectively around the inner reinforcing element 16 of the axially inner end 10 and around the outer reinforcing element 15 of the axially outer end 9. In the body 11, the main and return portions of the said reinforcing layer thus constitute a substantially radial stack of at least two reinforcing layers. The main reinforcement 17 is enveloped in a layer of elastomeric material 20. The body 11 further comprises an adapter seat 18 which is intended to come into contact with a tire bead. The body 11 has axial width L, measured between the axially inner face 21 of the axially outer end 9 and the axially outer face 26 of the axially inner end 10. In this first embodiment of the invention, the body 11 also comprises an annular seat reinforcer 19 radially on the outside of the main reinforcement 17 and axially on the inside of the axially outer end 9.

[0072] In FIG. 1, the outer reinforcing element 15 is an annular structure, referred to as a bead wire, having a mean line M and made up of a stack of three layers (23, 24, 25) made up of metal wires and concentric with respect to the mean line M. The first layer or core 23, which is radially the innermost layer, comprises at least one metal thread having a diameter D1 at least equal to 0.8 mm and at most equal to 5 mm. The second layer 24 is made up of a metal thread having a diameter D2 equal, in the instance depicted, to the diameter D1 and wound in a helix around the core 23, forming, with the mean line M of the bead wire 15, an angle A2 (not depicted) at least equal to 2 and at most equal to 10. The third layer 25 is made up of a metal thread having a diameter D3 equal, in the instance depicted, to the diameter D2 and wound in a helix around the second layer 24, forming, with the mean line M of the bead wire 15, an angle A3 (not depicted) at least equal to 2 and at most equal to 10, and of opposite sign to that of the angle A2. In the instance depicted, the core is made up of a single metal thread, the second layer 24 has a number N2 of sections of individual thread equal to 6, and the third layer 25 has a number N3 of sections of individual thread equal to 12.

[0073] FIG. 2 differs from FIG. 1 only in the omission of the annular seat reinforcer (19).

[0074] FIG. 3 shows a radial section, in a plane YZ, of a rolling assembly comprising a tire P, a rim J, and, for each bead B, an adapter A providing the connection between the bead B and the rim J. The tire P comprises a tread (unreferenced) extended radially towards the inside by two sidewalls 1, themselves extended radially towards the inside by two beads B. Within each bead B, the carcass reinforcement 2 is turned up around a circumferential reinforcing element or bead wire 3 to form a turnup 4 separated from the carcass reinforcement 2 by a filling element 5. The rim J comprises, in a middle portion, a mounting well 6, intended to make it easier to mount the beads B of the tire P and, at its axial ends, two rim bead seats 8, each one comprising a substantially radial portion or rim flange 7a and substantially axial portion or rim seat 7b. The adapter A comprises a radially inner end 10 comprising an inner reinforcing element 16 and intended to be mounted on a rim bead seat 8, an axially outer end 9 comprising an outer reinforcing element 15 and intended to come into contact via a substantially radial axially inner face or bearing face 21 with a bead B, and finally a body 11, connecting the axially outer end 9 to the axially inner end 10 so as to form a single piece, and comprising at least one main reinforcement 17 providing the connection between the outer reinforcing element 15 and the inner reinforcing element 16, and comprising a substantially axial adapter seat 18 intended to come into contact with a bead B.

[0075] By way of illustration, two examples of bead wires were evaluated as adapter outer reinforcing element 15.

[0076] The first example is a bead wire made up of 3 layers of steel reinforcers. The radially innermost first layer or core 23 comprises a metal thread having a diameter D1 equal to 3 mm. The second layer 24 is made up of a metal thread having a diameter D2 equal to 1.75 mm and wound in a helix around the core 23, forming, with the mean line M of the bead wire 15, an angle A2 (not depicted) equal to 6.2. The third layer 25 is made up of a metal thread having a diameter D3 equal to the diameter D2, namely to 1.75 mm, and wound in a helix around the second layer 24, forming, with the mean line M of the bead wire 15, an angle A3 (not depicted) equal to 8.8, and of opposite sign to that of the angle A2. In this instance, the second layer 24 has a number N2 of sections of individual thread equal to 8, and the third layer 25 has a number N3 of sections of individual thread equal to 14. The formula for this bead wire is therefore 1*3 mm+8*1.75 mm+14*1.75 mm.

[0077] The second example, corresponding to the scenario illustrated in FIGS. 2 and 3, is a bead wire made up of 3 layers of steel reinforcers. The radially innermost first layer or core 23 comprises a metal thread having a diameter D1 equal to 2 mm. The second layer 24 is made up of a metal thread having a diameter D2 equal to the diameter D1, namely to 2 mm and wound in a helix around the core 23, forming, with the mean line M of the bead wire 15, an angle A2 (not depicted) equal to 3.3. The third layer 25 is made up of a metal thread having a diameter D3 equal to the diameter D2, namely to 2 mm, and wound in a helix around the second layer 24, forming, with the mean line M of the bead wire 15, an angle A3 (not depicted) equal to 6.6, and of opposite sign to that of the angle A2. In this instance, the second layer 24 has a number N2 of sections of individual thread equal to 6, and the third layer 25 has a number N3 of sections of individual thread equal to 12. The formula for this bead wire is therefore (1+6+12)*2 mm.

[0078] The first example of bead wire of formula (1*3 mm+8*1.75 mm+14*1.75 mm) was incorporated into an adapter for a tire of size 225/45R17 mounted on a 4.5B16 wheel. Furthermore, this bead wire has a toric shape with an inside diameter equal to 471 mm and a mass equal to 713 g. This rolling assembly S1, comprising two adapters (one adapter per bead), was compared on the one hand against a standard reference rolling assembly R1 with no adapter, comprising a tire of size 225/45R17 mounted on a 7.5J17 wheel, and, on the other hand, against a rolling assembly E1 comprising a tire of size 225/45R17 mounted on a 7.5J17 wheel, and two adapters (one adapter per bead). Each adapter of the rolling assembly E1 has, as outer reinforcing element, a solid bead wire the radial cross section of which is a disc of diameter 10 mm and the constituent material of which is a glass-resin composite, namely one containing glass fibres in a resin matrix.

[0079] For each of the three rolling assemblies S1, R1 and E1 described hereinabove, the cornering stiffness DZ and the radial stiffness KZ were measured. The cornering stiffness DZ, expressed in daN/, is the axial force that has to be applied to the tire in order to generate a 1 rotation of the rolling assembly about a radial axis. In this instance, the cornering stiffness DZ is measured for a tire inflated to a pressure equal to 2.5 bar and compressed under a radial load Z equal to 4286 N. The radial stiffness KZ, expressed in daN/mm, is the radial force that has to be applied to the tire in order to obtain a radial movement of 1 mm. In this instance, the radial stiffness KZ is measured for a tire inflated to a pressure P equal to 2.5 bar, its nominal load Z, within the meaning of the ETRTO (European Tire and Rim Technical Organization) standard, being equal to 3620 daN. In the table below, the cornering stiffness DZ and radial stiffness KZ of the tires of the rolling assemblies S1, R1 and E1 compared are expressed in the form of a relative value with respect to reference rolling assembly R1, considered as the base 100.

[0080] Furthermore, the three rolling assemblies S1, R1 and E1 were subjected to a pinch shock test, followed by an endurance test. A pinch shock test consists in subjecting the tire, inflated to a pressure P equal to 2.3 bar, compressed under a load Z equal to 500 daN and running at 45 km/h, to repeated impacts against a kerb 110 mm high, in a direction that makes an angle equal to 70 with respect to the direction of travel. At the end of this pinch shock test, an endurance test is performed in which the tire, running at 30 km/h, is subjected to cornering angles varying between 6 and +6 about the radial direction. The integrity of the tire is then examined at the end of this sequence of two tests.

[0081] Table 1 hereinbelow presents the results of cornering stiffness DZ, radial stiffness KZ and cornering endurance test following a pinch shock test for the rolling assemblies R1, E1 and S1 for a tire of size 225/45R17:

TABLE-US-00001 TABLE 1 Cornering stiffness, radial stiffness and endurance on 225/45R17 Cornering Radial stiffness stiffness DZ KZ Integrity in cornering (Z = 4826 N, (Z = 3620 N, endurance after Rolling assembly P = 2.5 bar) P = 2.5 bar) pinch shock test R1: Tire 225/45R17 + 100% 100% NA (puncture) wheel 7.5J17 E1: Tire 225/45R17 + 2 adapters with 96% 98% NOK (bead wire external bead wire made of CVR breakage) (diam. ext 10 mm) + wheel 4.5B16 S1: Tire 225/45R17 + 2 adapters with 97% 98% OK external bead wire of formula (1 * 3 mm + 8 * 1.75 mm + 14 * 1.75 mm diam. ext 10 mm) + wheel 4.5B16

[0082] Table 1 shows that the two rolling assemblies E1 and S1 with adapters have cornering stiffnesses DZ and radial stiffnesses KZ of substantially the same magnitude as those of the reference rolling assembly R1 without adapter. By contrast, rolling assembly S1 performs better than rolling assembly D1 in the endurance test after the pinch shock test because the adapter bead wire remains intact for S1 whereas the adapter bead wire for E1 has broken.

[0083] Table 2 below shows the same type of results for three rolling assemblies R2, S21 and S22 in the case of a tire of size 245/40R18. The standard reference rolling assembly R2, without adapter, comprises a tire of size 245/40R18 mounted on a 8J17 wheel. The rolling assembly S21 comprises a tire of size 245/40R18 mounted on a 4.5J16 wheel, and two adapters (one adapter per bead). Each adapter of the rolling assembly S21 has, as outer reinforcing element, a bead wire of formula (1*3 mm+8*1.75 mm+14*1.75 mm) the circular radial cross section of which has a diameter equal to 10 mm. The rolling assembly S22 comprises a tire of size 245/40R18 mounted on a 4.5J16 wheel, and two adapters (one adapter per bead). Each adapter of the rolling assembly S22 has, as outer reinforcing element, a bead wire of formula (1+6+12)*2 mm the circular radial cross section of which has a diameter of 10 mm. Furthermore, this bead wire has a toric shape with an inside diameter equal to 471 mm and a mass equal to 707 g.

[0084] Table 2 below presents the results of cornering stiffness DZ, radial stiffness KZ and cornering endurance test following a pinch shock test for the rolling assemblies R2, S21 and S22 for a tire of size 245/40R18:

TABLE-US-00002 TABLE 2 Cornering stiffness, radial stiffness and endurance on 245/40R18 Cornering Radial stiffness stiffness DZ KZ Integrity in cornering (Z = 5101 N, (Z = 3826 N, endurance after Rolling assembly P = 2.5 bar) P = 2.5 bar) pinch shock test R2: Tire 245/40R18 + 100% 100% NA (puncture) wheel 8J17 S21: Tire 245/40R18 + 2 adapters 99% 99% OK with external bead wire of formula (1 * 3 mm + 8 * 1.75 mm + 14 * 1.75 mm diam. ext 10 mm) + wheel 4.5J16 S22: Tire 245/40R18 + 2 adapters 98% 99% OK with external bead wire of formula (1 + 6 + 12) * 2 mm avec diam. ext 10 mm) + wheel 4.5J16

[0085] Table 2 shows that the two rolling assemblies S21 and S22 with adapters have cornering stiffnesses DZ and radial stiffnesses KZ of substantially the same magnitude as those of the reference rolling assembly R2 without adapter. In addition, the two rolling assemblies S21 and S22 both pass the endurance test following a pinch shock test.