Flexible Wheel Rim With Floating Hooks

Abstract

Vehicle rim for mounting of a tire, comprising: an axially central part (20) comprising a disc; two lateral parts (31, 32), at least one of the lateral parts being separate from the axially central part, each of the lateral parts having a rim seat to receive a bead of a tire, the axially central part and the two lateral parts being made from a rigid matrix; an intermediate part (41, 42) that forms the only mechanical link between the axially central part and each lateral part that is separate from the axially central part, this intermediate part being made of a flexible matrix, the Young's modulus of uniaxial extension of the flexible matrix being greater than and equal to 50 MPa and less than or equal to 400 MPa; wherein the Young's modulus of uniaxial extension of the rigid matrix is greater than or equal to 5 GPa.

Claims

1. A vehicle rim, with symmetry of revolution, adapted for the mounting of a tire, comprising: an axially central part comprising a disc; two lateral parts, at least one of the lateral parts being separate from the axially central part, each of the lateral parts being provided with a rim seat intended to receive a bead of a tire, the axially central part and the two lateral parts being made from a rigid matrix that can be reinforced by a reinforcement; an intermediate part that forms the only mechanical link between the axially central part and each lateral part that is separate from the axially central part, this intermediate part being comprised of a flexible matrix, the Young's modulus of uniaxial extension of the flexible matrix being greater than and equal to 50 MPa and less than or equal to 400 MPa; wherein the Young's modulus of uniaxial extension of the rigid matrix is greater than or equal to 5 GPa.

2. The vehicle rim according to claim 1, wherein the contact between the axially central part and each intermediate part is made by one end of the axially central part which passes into the intermediate part.

3. The vehicle rim according to claim 2, wherein said end of the axially central part comprises an overthickness that makes it possible to anchor the end in the intermediate part.

4. The vehicle rim according to claim 1, wherein the contact between each lateral part that is separate from the axially central part and the intermediate part in contact therewith is made by one end of the lateral part which passes into the intermediate part.

5. The vehicle rim according to claim 4, wherein said end of the lateral part comprises an overthickness that makes it possible to anchor the end in the intermediate part.

6. The vehicle rim according to claim 1, wherein each lateral part that is separate from the axially central part is entirely covered with the material of which the flexible matrix of the intermediate part in contact therewith is made.

7. The vehicle rim according to claim 1, comprising two intermediate parts, wherein the two intermediate parts are symmetrical to one another.

8. The vehicle rim according to claim 1, wherein the material of which the flexible matrix of each intermediate part is made is comprised of polyurethane.

9. The vehicle rim according to claim 1, wherein the material of which the flexible matrix of each intermediate part is made is comprised of a rubber composition.

10. The vehicle rim according to claim 1, wherein the material of which the flexible matrix of each intermediate part is made is comprised of a thermoplastic elastomer.

11. The vehicle rim according to claim 1, wherein the material of which the rigid matrix of the axially central part and the two lateral parts is made is comprised of a metal or a metal alloy.

12. The vehicle rim according to claim 1, wherein the Young's modulus of uniaxial extension of the rigid matrix is greater than the Young's modulus of uniaxial extension of the flexible matrix by a factor of greater than or equal to 100.

13. The vehicle rim according to claim 1, wherein both of said two lateral parts are separate from said axially central part.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG. 1 shows, in radial cross section, a tire-wheel assembly.

[0020] FIGS. 2 to 6 each show a part of a rim according to the invention.

[0021] All of the figures are schematic.

DETAILED DESCRIPTION OF THE INVENTION

[0022] Where the term radial is used, a distinction should be made between several different uses of the word by a person skilled in the art. Firstly, the expression refers to a radius of the rim (and of the tire with which the latter is equipped). It is within this meaning that a point P1 is said to be radially inside a point P2 (or radially on the inside of the point P2) if it is closer to the rotation axis than the point P2. Conversely, a point P3 is said to be radially outside a point P4 (or radially on the outside of the point P4) if it is further away from the rotation axis of the tire than the point P4. Progress will be said to be radially inwards (or outwards) when it is in the direction of smaller (or larger) radii. It is this sense of the term that applies also when radial distances are being discussed.

[0023] On the other hand, a thread or a reinforcement is said to be radial when the thread or the reinforcement elements of the reinforcement make an angle greater than or equal to 80 and less than or equal to 90 with the circumferential direction. Let us specify that, in this document, the term thread should be understood in a very general sense and comprises threads in the form of monofilaments, multifilaments, a cord, a folded yarn or an equivalent assembly, irrespective of the material of which the thread is made or of the surface treatment it has received in order to encourage it to bond with the rubber.

[0024] Finally, a radial cross section or radial section means here a cross section or a section in a plane which contains the rotation axis of the rim (and of the tire with which the latter is equipped).

[0025] An axial direction is a direction parallel to the rotation axis of the rim (and of the tire with which the latter is equipped). A point P5 is said to be axially inside a point P6 (or axially on the inside of the point P6) if it is closer to the median plane of the rim than the point P6. Conversely, a point P7 is said to be axially outside a point P8 (or axially on the outside of the point P8) if it is further away from the median plane of the rim than the point P8. The median plane of the rim is the plane which is perpendicular to the rotation axis of the rim and which is situated equidistantly from the rim seats intended to receive a bead of a tire.

[0026] A circumferential direction is a direction which is perpendicular both to a radius of the rim and to the axial direction.

[0027] In the scope of this document, the expression rubber composition denotes a composition of rubber comprising at least one elastomer and a filler.

[0028] The Young's modulus of uniaxial extension of a material is understood here as meaning the modulus of extension measured using a tensile test. For the flexible matrices and the textile reinforcement elements, the process according to the standard DIN EN ISO 527-2 was carried out on a test specimen of type A according to the standard DIN EN ISO 3167 at a pull rate of 1 mm/min. For the rigid matrices and the metal reinforcement elements, by contrast, the process according to the standard ASTM E111-04(2010) was carried out.

[0029] FIG. 1 shows, in radial cross section, a tire-wheel assembly comprising a tire 5. The tire 5 is mounted on a hollow mounting rim 10 in accordance with the standards of the ETRTO (European Tire and Rim Technical Organisation). The common rotation axis bears the reference 1.

[0030] FIG. 2 shows, in radial cross section, a part of a rim 10 according to the invention. This rim 10 comprises an axially central part 20 comprising a disc (not shown), two lateral parts 31 and 32 and an intermediate part 41. The lateral part 31 is separate from the axially central part 20 while the lateral part 32 is in one piece therewith. Each of the lateral parts 31 and 32 is provided with a rim seat intended to receive a bead of a tire (not shown). The axially central part 20 and the two lateral parts 31 and 32 are made of a rigid matrix that can be reinforced by a reinforcement. In the present case, these parts are made of steel having a Young's modulus of uniaxial extension equal to 190 GPa. The intermediate part 41 forms the only mechanical link between the axially central part 20 and the lateral part 31; it is made of a flexible matrix, in the present case polyurethane. The Young's modulus of uniaxial extension of this flexible matrix is equal to 90 MPa.

[0031] FIG. 3 shows, in radial cross section, a part of a rim 10 according to another embodiment of the invention. In contrast to the rim in FIG. 2, the two lateral parts 31 and 32 are separate from the axially central part 20 and there are two intermediate parts 41 and 42 made of polyurethane.

[0032] FIG. 4 shows, in radial cross section, a part of another rim according to the invention. Here, the contact between the axially central part 20 and the intermediate part 42 is made by one end 21 of the axially central part 20 which passes into the intermediate part 42. Similarly, the contact between the lateral part 32 (which is separate from the axially central part 20) and the intermediate part 42 in contact therewith is made by one end 34 of the lateral part 32 which passes into the intermediate part 42.

[0033] FIG. 5 shows, in radial cross section, a part of another rim according to the invention. In the present case, the end 21 of the axially central part 20 comprises an overthickness 22 that makes it possible to anchor the end in the intermediate part 32. Similarly, the end 34 of the lateral part 32 comprises an overthickness 33 that makes it possible to anchor the end 34 in the intermediate part 42.

[0034] FIG. 6 shows, in radial cross section, a part of another rim according to the invention. Here, the lateral part 32 (which is separate from the axially central part 20) is entirely covered with the material of which the flexible matrix of the intermediate part 42 in contact therewith is made.

[0035] Tests were carried out with a rim comprising two flexible intermediate parts corresponding to FIG. 5, the intermediate part being made of polyurethane having a Young's modulus of 90 MPa. The wheel was mounted on the front axle assembly of a Peugeot 307 HDI vehicle. Noise measurements made it possible to note a significant decrease in the noise perceived at the driver's seat over the bands 80-100 Hz, 140-170 Hz and 340-380 Hz, compared with a wheel comprising an equivalent rim that does not have flexible intermediate parts. Kerb impact tests also confirmed an improvement in the resistance of the tire-wheel assembly to impacts.