WO2018109309A1

WO2018109309A1 - Assembly provided with a tyre of very small size

Info

Publication number: WO2018109309A1
Application number: PCT/FR2017/053365
Authority: WO
Inventors: Michel Ahouanto; José Merino Lopez; Jacky Pineau
Original assignee: Compagnie Generale Des Etablissements Michelin
Priority date: 2016-12-15
Filing date: 2017-12-04
Publication date: 2018-06-21
Also published as: FR3060450B1; FR3060450A1

Abstract

Rolling assembly having an axis of rotation and comprising: - a tyre (P) having two beads (B), each linked to a sidewall (1); - a rim having two seats for receiving a tyre, said rim comprising a rigid central portion and comprising two axially lateral portions, each including one of the seats for a tyre, at least one of said seats being radially floating, characterized in that the sidewalls (1) of the tyre have a radial height (H) that is less than or equal to 78 mm.

Description

ASSEMBLY WITH A VERY LOW-SIZED PNEUMATIC

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a rolling assembly for equipping a passenger vehicle and whose tire is provided with very low sidewalls. It also relates to said wheel assembly, consisting of a tire, a rim and two adapters ensuring the connection between the two beads of the tire and the rim.

STATE OF THE PRIOR ART

A tire being a toroidal structure whose axis of revolution is its axis of rotation, it can be described in a radial plane passing through its axis of rotation. In what follows, for any radial plane, the radial, axial and circumferential directions respectively designate the directions perpendicular to the axis of rotation of the tire, parallel to the axis of rotation of the tire and perpendicular to the radial plane. The equatorial plane designates the plane passing through the middle of the tread and perpendicular to the axis of rotation of the tire. Radial section is defined as any section of the tire in a radial plane. In general, a tire comprises a tread intended to come into contact with a ground, two sidewalls extending radially inwardly the axial ends of the tread and two beads extending radially inwardly the two sidewalls and intended to come into contact with a rim. On some rather sporty passenger vehicles, there are often tires with very low sidewalls (also commonly referred to as "low tire size"). These tires provide many benefits in terms of handling and driving sensations, while contributing to the development of the vehicle. In return, because of the low height of the flanks, it is common that some efforts, not detrimental to tires with higher sidewall, are transmitted via the rim to the vehicle. Some efforts are felt by the occupants of the vehicle and can affect comfort in the cabin, sometimes significantly. [0004] In addition, the sources of transmissible excitations are very numerous and common on the roads. It can for example be small unevenness of the roadway, manholes, etc.

Other irregularities on the roads are more important, such as potholes or sidewalks. If such obstacles are encountered with short-side tires and at an insufficiently moderate speed, the vehicle may suffer some damage, forcing the driver to stop. For all these reasons, we can not adopt flanking heights too low. And even certain dimensions, with very short sides, know only limited broadcasts, limited to very sporting vehicles.

The object of the invention is to overcome these various disadvantages.

SUMMARY OF THE INVENTION

First, a first object of the invention is to allow the use of low sidewall tires without suffering the disadvantages inherent in the lack of noise and vibration comfort. Another object of the invention is to allow the use of short-side tires by avoiding that the driver must immobilize his vehicle (damaged) because he drove a little fast on an obstacle or on a road with a pothole somewhat deep. To do this, the invention provides a rolling assembly having an axis of rotation and comprising:

a tire having two beads each connected to a sidewall,

a rim having two seats for receiving a tire, said rim comprising a rigid central part and comprising two axially lateral parts each comprising one of the seats for tires, at least one of said seats being floating radially, characterized in that the tire sidewalls have a radial height less than or equal to 78mm. Thus, the invention proposes a new use of a roller assembly with flexible adapter interposed between rim and tire bead as described in the patent application WO2015 / 091618. Such an arrangement makes it possible to greatly reduce the increase in forces in the vehicle when driving with tires having sidewalls of very low height. Such mounted assembly provides outstanding efficiency to reduce vibration and improve driving comfort. The mounted assembly also provides impact protection on sidewalks and potholes. According to an advantageous embodiment, the flanks have a radial height less than or equal to 74 mm, and more preferably less than or equal to 70 mm.

Most often, it is advantageous that the two seats for receiving a tire are floating radially. Note also that the invention is not limited to the use of an adapter as described in the aforementioned patent application. Other forms of rim with floating seat are known. For example, see patent application WO2015 / 158472, which proposes a single adapter for forming a rim with floating seats, the middle part of this adapter being fixed on a wheel disk; we also consult the patent application WO2015 / 091621 which proposes a rim whose axially intermediate zone between a center of rim and each seat is itself flexible to the service requirements. All these rims with floating seats lend themselves to the formation of wheel sets whose tire is of very small size. In a particularly advantageous implementation, the roller assembly according to the invention comprises a completely rigid rim, said assembly comprising an adapter ensuring the junction between one of the beads and said rim, said at least one radially floating seat. , for receiving a tire, being arranged on said adapter. The use of an adapter as a separate part of a rim is an implementation of the invention facilitating the industrial realization.

In a still more particular embodiment, in that it is axially symmetrical, the invention uses two flexible adapters as described in the patent application WO2015 / 158472. In this case, the wheel assembly according to the invention is remarkable in that the rim comprises two rim seats, said assembly comprising two adapters ensuring the junction between one of the beads and the rim, the rim having two seats on the rim , each adapter comprising:

an axially inner end intended to be mounted on one of the seats on the rim,

an axially outer end,

a body connecting said outer end with said inner end so as to form a unitary piece,

a substantially cylindrical adapter seat intended to receive one of said beads, said seat being situated at the axially outer end of said body,

- An adapter bearing face substantially within a plane perpendicular to the axis of rotation, said bearing face being located on the axially inner face of the axially outer end.

These elements contribute to the smooth running of the whole.

Preferably, the adapter is formed by a matrix comprising an elastomeric composition and reinforcements.

[0017] Preferably, the axially inner end of the adapter comprises an inner reinforcing element, the axially outer end comprises a external reinforcing element, the body comprises at least one main reinforcing armature providing the connection between the outer reinforcing element and the inner reinforcing element. The invention also provides a tire for a mounted assembly as previously described in FIG. the H / B ratio is less than or equal to 15. Preferably, the H / B ratio is less than or equal to 10. This dimensional ratio corresponds to tires that are currently non-existent on the market because of the limitations resulting from the use of standard rims. Thus, thanks to the invention, vehicle manufacturers and users will benefit from new dimensional ranges.

According to an advantageous variant, the H / B ratio is less than or equal to 45. Low enough sizes are more accessible thanks to the present invention: H / B ratio equal to 40 or 35 or 30 or 25 or 20, or any intermediate value. Of course, all the values of H / B given here only respect the value steps for H / B according to the current standardization, which is in no way limiting. Thanks to the assembled assembly and to the tire of the invention, the H / B values that are currently absent or that can only be found for niche applications can henceforth be used on a large number of vehicles or on a larger scale. number of vehicles because of the improved comfort level.

DESCRIPTION OF THE FIGURES

All the details of embodiment are given in the description which follows, supplemented by FIGS. 1A to 3, presented solely for purposes of non-limiting examples, and in which:

FIGS. 1A and 2 schematically illustrate the crushing characteristics of the sidewalls for a high-waist tire (FIG. 1A) and a low-profile tire (FIG. 2); Figure 3 is a radial section of an example of a rolling assembly according to the invention (schematic figure).

DETAILED DESCRIPTION OF THE INVENTION

Figures 1A and 2 illustrate a significant dynamic difference between the dynamic behavior of high sidewall and shortwall tires in the case of mounting on a standard wheel, and crushed with a load and nominal pressures. As shown in FIG. 1A, in the dimensions provided with high flanks (by convention, in the context of the present invention, the high or high sidewall of the series 45 and higher series tires, for example 165/60 R 15 ), in crushing phase of the sidewall, the internal reinforcing structure, commonly referred to as carcass ply, is generally axially outside the rim. On the other hand, for the short flanks, that is to say for the low sizes (for example 285 / 25ZR20), as shown in FIG. 2, also in the crushing phase, the internal reinforcement structure will be located axially inside the rim. Thus, for short-side tires, the following dimensional ratios are observed: the LMNC dimension (for maximum width of carcass web measured at the equator of the tire, ie at the point of greatest width) is less than the dimension. MRL (for Maximum Width of the Wheel). Figure 3 shows a radial section of a roller assembly comprising a tire P, a rim J and, for each bead B, an adapter A on each side axially, ensuring the junction between the bead B and the rim J. The tire P comprises a tread extended radially inwards by two flanks 1, themselves extended radially inwards by two beads B. In each bead B, the carcass reinforcement 2 wraps around a circumferential reinforcement element or rod 3, to form a separate upturn 4 of the carcass reinforcement 2 by a filling element 5. The rim J comprises, in a median portion, a groove assembly 6, intended to facilitate the mounting of the beads B of the tire P, and at its axial ends, two rim flanges each comprising a substantially radial portion or rim hook 7 and a substantially axial portion or seat 8 de rim.

The flanks 1 of the tire have a radial height H less than or equal to 78 mm, more preferably less than or equal to 74 mm, and even more preferably less than or equal to 70 mm.

As for the adapter A, it is formed by a matrix comprising an elastomeric composition and reinforcements. The main elements of the adapter are an axially inner end 10 intended to be mounted on the rim J, an axially outer end 9 intended to come into contact with an axially inner, substantially radial face, or bearing face 21, with a bead B. The reader is referred to the patent application WO2015 / 091618 already cited, which gives additional information. Thus, in this exemplary embodiment illustrated in FIG. 3, which is in no way limiting and in accordance with the above-mentioned patent application, the axially inner end 10 comprises an inner reinforcing element 16. Moreover, the axially outer end 9 comprises an element 15. A body 1 1 connects the axially outer end 9 with the axially inner end 10 so as to form a unitary piece. The adapter comprises at least one main reinforcing armature 17 providing the connection between the outer reinforcing element 15 and the inner reinforcing element 16. The adapter comprises a seat 23 on an adapter, oriented substantially axially, intended to receive a bead B. The main reinforcing armature 17 comprises at least one or more reinforcing plies each comprise reinforcements coated with elastomeric composition. The seat 23 on the adapter comprises an annular seat reinforcement 19, all of which is disposed near the radially outer surface of the body surface January 1. The body 1 1 has an axial width L, measured between the bearing face 21 of the axially outer end 9 and the axially outer face 22 of the axially inner end 10. As an example, the length L may be 3.175 cm (1.25 inches). The following comparative example shows the results obtained with a rolling assembly according to the invention. The low-profile tire (285 / 25ZR20) (FIG. 2) is such that the sidewall height is 68 mm. The Adapter A used has a 21 "adapter seat, to accommodate the 21" tire and is mounted on a 20 "rim The outer reinforcement is a braided rod, the length L is 40.1 mm. Figure 1A) 165/60 R 15 has a flank height of 94 mm.

Test performed

Obstacle clearance test

The proposed test is the passage of the vehicle on a bar of dimensions 10x10 mm with the same type of tire in two configurations: A) with standard wheel, and B) with a mounted assembly provided with adapters. The rolling is performed on an Audi ® RS6 vehicle at a speed of 50 Km / h. The tire is inflated every time to 2.8 bar and rolls with a load of 580 Kg. The study tire used is of dimensions 285 / 30R21, and of the MICHELIN® PSS type.

Vibration measurements

Obstacle crossing test for validation of the acceleration values in X and Y: tests of crossing bars were made with standard wheels and wheels with adapter according to the invention. An accelerometer is attached to the floor of the car. When driving, the signal of the accelerometer is recorded. Accelerations X are those measured on a horizontal axis in the direction of travel of the car, in the direction of speed: longitudinal direction. Y accelerations are measured on a horizontal axis perpendicular to the direction of velocity: transverse direction. Measurements are made when crossing obstacles. The following measurements were made: accelerations in the X or Y directions in time, measured in the vehicle during and after the passage of the bar. We retain the maximum amplitude between peaks. This test is important because the greater the acceleration, the greater the vibratory comfort is penalized. The objective is to minimize the X and Y accelerations.

Obstacle clearance test result

It is found that the gain is 13% in each direction. This demonstrates the possibility of using adapters for short-side tires. The acceleration along the axis of the load Z has remained substantially constant.

Acoustic measurements

In addition, acoustic measurements have made it possible to evaluate the gains in sound comfort with noise measurements inside the passenger compartment. Only one study wheel passes over the test bar. During testing, a manikin with microphones in the ears is placed in the front passenger seat. Noise is measured using an A filter (standard filter). With a mounted assembly fitted with adapters, the noise level measured in the passenger compartment Passenger side is 0.6dB weaker during bar impacts. This gain is significant and contributes to the overall comfort of the occupants of a vehicle.

Test conclusions

The results of the tests are very conclusive since there is a systematically lower acceleration for the assembly mounted according to the invention. The technical effect is to allow, in addition to reducing the forces during sidewalk impacts (large objects) to improve comfort by decreasing the X and Y accelerations when crossing small obstacles (example 10x10 mm bar of the example) ) and improving the interior noise.

The following table illustrates examples of tires that can be used with an assembly mounted according to the invention.

Dimensional table of tires for the mounted assembly

Some low-profile tires already exist on the market. On the other hand, certain dimensions, with very small sidewalls, such as for example series 20, 15 or 10, do not exist on the market. Finally, the dimensions of the series 25 exist but are rare on the market and limited to uses where the comfort is secondary and the risk of shock limited. Here are some examples of the dimensions extracted from this table:

- all the sizes of series 10 and 15 (nonexistent today on the market);

in series 25: the dimensions less than 310/25, preferentially less than 290/25 and even more preferably less than 280/25;

in series 20: the dimensions less than or equal to 390/20, preferably less than 370/20 and even more preferentially less than 350/20;

The assembly mounted according to the invention will allow dimensions that are not proposed today can be in the future and that marginal dimensions today can benefit from growth in the market. Alternatively, different adapter arrangements may be used to form a mounted assembly according to the invention. It can be bi-adapter (an adapter to carry each of the beads) or mono-adapter (a single adapter supporting the two beads). The details of embodiment, such as the materials, the types of reinforcements, the reinforcing plies, etc., of each of these adapters may vary according to the intended embodiments.

Claims

A rolling assembly having an axis of rotation and comprising:

a tire (P) having two beads (B) each connected to a sidewall (1), a rim having two seats for receiving a tire, said rim comprising a rigid central part and comprising two axially lateral parts each comprising one seats for tires, at least one of said seats being radially floating, characterized in that the sidewalls (1) of the tire have a height (H) radial less than or equal to 78 mm.

2 - rolling assembly according to claim 1, characterized in that the flanks (1) have a radial height less than or equal to 74 mm.

3 - rolling assembly according to claim 1, characterized in that the flanks (1) have a radial height less than or equal to 70 mm.

4 - rolling assembly according to any one of claims 1 to 3, characterized in that the two seats for receiving a tire are floating radially.

5. Rolling assembly according to any one of claims 1 to 4, characterized in that the rim is entirely rigid, said assembly comprising an adapter (A) ensuring the junction between one of the beads (B) and the rim (J). ), said at least one radially floating seat, for receiving a tire, being arranged on said adapter (A).

6. Rolling assembly according to claim 5, characterized in that the rim comprises two rim seats, said assembly comprising two adapter (A) ensuring the junction between one of the beads (B) and the rim (J), the rim having two seats (8) on rim, each adapter (A) comprising:

an axially inner end (10) intended to be mounted on one of the seats (8) on the rim, an axially outer end (9),

a body (1 1) connecting said outer end (9) with said inner end (10) so as to form a unitary piece,

an adapter seat (23), substantially cylindrical, intended to receive one of said beads (B) of said tire, said seat (23) being located at the axially outer end (9) of said body (1 1),

- An adapter bearing face (21) substantially in a plane perpendicular to the axis of rotation, said bearing face being located on the axially inner face of the axially outer end (9).

7. Rolling assembly according to claim 6, characterized in that the adapter (A) is formed by a matrix comprising an elastomeric composition and reinforcements.

8. Rolling assembly according to claim 7, characterized in that the axially inner end (10) of the adapter (A) comprises an inner reinforcing element (16), the axially outer end (9) comprises an element of outer reinforcement (15), the body (1 1) comprises at least one main reinforcing armature (17) providing the connection between the outer reinforcing element (15) and the inner reinforcing element (16).

9. Rolling assembly according to any one of claims 1 to 8, characterized in that the H / B ratio of the tire is less than or equal to 45.

Pneumatic tire assembly according to one of Claims 1 to 9, characterized in that the H / B ratio is less than or equal to