Patent Application
20170001472
The invention relates to an adapter for a rolling assembly formed mainly of a tire and a rim, and to a rolling assembly comprising said adapter.
A reminder of the definitions used in the present invention is given below:
It is already known from the application WO00/78565 to insert an elastic adapter between the rim and the beads of a tire. This adapter is elastically deformable in the radial and axial directions. Such an adapter makes it possible to separate that part of the rolling assembly that can be considered to actually act as a tire from that part of the rolling assembly that can be considered to act as a rim.
However, although such an assembly also makes it possible to ensure the functions of a conventional tire, notably a drift thrust response of the tire following the application of a drift angle to the tire, thereby giving the assembly sufficient flexibility for it to avoid any surface deterioration or depth deterioration, it does not perfectly ensure sufficient deformability of the tire in the event of impacts with kerbs or holes in the roadway, such as potholes.
This is because the assembly mounted with the adapter of the prior art does not make it possible to obtain a local deformation in the region of the contact patch. The teaching of that document also has the drawback of not making it easily possible to obtain embodiments of the adapter that afford a high capability of absorbing large deformations on passing through potholes without residual plastic deformations.
An adapter disposed between the bead of a tire and a rim and intended to solve the problems of mounting and removing a tire and a rim is also known from the document FR 2,491,836 A1. That adapter mainly comprises two annular bead wires that are spaced apart from one another and mounted inside an annular body comprising a ply. The bead wires are connected by a cord which, moreover, surrounds them.
These documents give no suggestions for architectural adaptations which would lead to an outer reinforcer deformation that is localized in the region of the contact patch resulting in a reduced camber and thus making the mounted assembly less intrusive with regard to the vehicle.
Therefore, there is a need to have a novel adapter which ensures better protection of the tire in the event of impacts with the tire that are due to use on roads in poor condition, thereby minimizing as far as possible partial or even total damage to its internal structure, while keeping the road holding performance of the tire at a high level, in particular its ability to develop high drift thrusts. Moreover, at the very least, in the event of damage due to unusually harsh use, it is a question of keeping the vehicle safe through its movement over a short distance following an impact that destroys the assembly.
The subject of the invention is thus an adapter for a rolling assembly having a rotation axis and comprising:
The adapter is characterized in that the reinforcer of the axially outer end is entirely outside the bearing face, and in that the body comprises, opposite the adapter seat, an annular seat reinforcer having a compression modulus greater than or equal to 1 GPa.
The adapter according to the invention has the advantage of having a simple design and being easy to mount. Moreover, owing to the increase in clamping under the beads of the tire, the adapter according to the invention makes it possible to prevent the rotation thereof on the adapter under high lateral stress.
Finally, the adapter according to the invention has the advantage of significantly reducing the level of mechanical forces towards the chassis in the event of an impact, and thus of making it possible to make the body shell of the vehicle lighter.
Another subject of the invention is a rolling assembly having a rotation axis and comprising:
This rolling assembly is characterized in that the reinforcer element of the axially outer end is entirely situated axially outside the bearing face, and in that the body comprises, opposite the adapter seat, an annular seat reinforcer.
The adapter allows a rolling assembly to have sufficient radial deformations between the bead of the tire and the rim, during its use and while it is inflated to a nominal pressure, to allow the desired protection with regard to lateral impacts.
The axially outer end of the adapter delimits, axially, a “housing intended to receive the bead of the tire”. The bearing face of the axially outer end serves to support the bead of the tire in the axial direction, in the same way as a rim flange.
In this way, the housing receives the bead of the tire just as the seat of a rim conventionally does. The tire is then immobilized axially by the inflation pressure and is pressed against the bearing face of this axially outer end in the same way as is conventionally done for the bead of a tire against the rim flange of a rim.
The axially inner end of the adapter may be denoted “adapter bead” since it is intended to couple the adapter to the rim flange of a rim in the same way as is conventionally done by the bead of a tire.
Thus, with the rolling assembly according to the invention in operation and at the operating stresses for which it is designed, the tire is immobilized axially with respect to the rim, more specifically the beads of the tire are immobilized axially with respect to the rim in the same way as for a conventional rolling assembly in which the beads of the tire are mounted directly on the seats of a rim, and the beads of the tire are not immobilized radially with respect to the rim, more specifically the beads of the tire are capable of a degree of radial movement with respect to the rim. Under standard rolling conditions, it may be said that there is virtually no axial deformation of the adapter, or it is negligible with respect to the radial deformation.
On the other hand, during an impact, the axial deformation of the adapter can be great, thereby contributing to reducing the stresses on the mounted assembly.
Preferably, the annular seat reinforcer has a compression modulus greater than or equal to 4 GPa, and more preferably greater than or equal to 10 GPa. The annular reinforcer may be made up of a core surrounded by an elastomer, or of a succession of layers of elastomer compounds and metal and/or textile reinforcers disposed in any possible combination. The core may comprise at least one element chosen from a metal, a composite material, a thermoplastic, and a mixture thereof. The composite material may be made from glass fibres embedded in a resin matrix.
The list of elastomers that can be used includes, firstly, rubbers that are crosslinkable by chemical vulcanization reactions by sulphur bridges, by carbon-carbon bonds created by the action of peroxides or of ionizing radiation, by other specific atom chains of the elastomer molecule, secondly, thermoplastic elastomers (TPEs) in which the elastically deformable part forms a network between rather non-deformable “hard” regions, the cohesion of which is the product of physical connections (crystallites or amorphous regions above their glass transition temperature), and next non-thermoplastic elastomers and finally thermoset resins.
The annular seat reinforcer may be made up of at least two layers of different constituents disposed successively in alternation. Disposition in alternation means successive disposition of a first layer and then a second layer, several times.
The annular seat reinforcer may have an overall axial length greater than or equal to 30% of the width of the bead of the tire, and less than 150% of this same width, and more preferably between 40 and 110% of the width of the bead of the tire.
The annular seat reinforcer may have a mean radial thickness greater than or equal to 0.3 mm and less than or equal to 20 mm depending on the size and the use of the tire. Thus, for a passenger car tire, the thickness is preferably between 0.5 and 10 mm.
The annular seat reinforcer preferably comprises at least one element chosen from a metal, a composite material, a thermoplastic, and a mixture thereof. This core or this multilayer is preferably contained between two layers of a matrix comprising the choice of an elastomer as cited above, a resin or a mixture thereof.
The annular seat reinforcer preferably consists of a stack of different layers of elastomer compounds with an identical or different chemical nature.
When it is in the form of a stack of layers, the reinforcer preferably has an axial length greater than 5 mm and less than 25 mm and a radial thickness greater than or equal to 0.1 mm and less than or equal to 4 mm.
Each single element of which the stack of the reinforcer is made may have an axial length greater than 1 mm and less than 25 mm and an identical or different radial thickness greater than or equal to 0.1 mm and less than or equal to 2 mm.
The annular seat reinforcer may also be in the form of a stack of single threads between a layer of a matrix comprising the choice of an elastomer, a thermoplastic compound, a resin, or a mixture thereof. The single threads may be threads that are conventionally used, such as textile threads (polyester, nylon, PET, aramid, rayon, natural fibres (cotton, flax, hemp)), metal threads, composite threads (carbon, glass-reinforced plastic), or mixtures of these constituents.
The annular seat reinforcer may also be in the form of one or more plies, the reinforcers of which are disposed at an angle of between 0 and 90° with respect to the circumferential direction of the tire.
Preferably, the annular reinforcer may be disposed radially outside or radially inside the body of the adapter, on either side of said body, or else between the plies of reinforcing elements of the body of the adapter.
The outer reinforcer element may consist of metal (steel), nylon, PET or aramid. It may comprise a matrix of resin and/or reinforcing fibres, such as rayon, aramid, PET, nylon, glass fibre, carbon fibre, basalt fibre, poly(ethylene 2,6-naphthalate) (PEN), or polyvinyl alcohol (PVA).
The main reinforcement of said body may have a modulus greater than or equal to 4 GPa; it may consist of metal (steel), of textile cord (rayon, aramid, PET, nylon, glass fibre, carbon fibre, basalt fibre, poly(ethylene 2,6-naphthalate) (PEN), or polyvinyl alcohol (PVA).
Preferably, the adapter may be disposed on one side of the rim, and preferably on the outer side of the vehicle. In this case, the rim has an asymmetrical geometric shape so as to adapt to the presence of the adapter present on one side.
When the mounted assembly comprises two adapters, the latter may be symmetrical or non-symmetrical. The concept of symmetry or asymmetry of the adapter is defined by the axial length of the body of the adapter. Two adapters are asymmetrical when the body of one of them has an axial length greater than that of the other.
Preferably, the rolling assembly comprises a first and a second adapter that each have a body with an identical or different length.
The invention will now be described with the aid of examples and figures which follow and which are given purely by way of illustration, and in which:
The tire, which is of unaltered design per se in the invention, consists of a tread reinforced by a crown reinforcement joined to two beads B on either side of an equatorial plane XX' by way of two sidewalls 1. A carcass reinforcement 2 that mainly reinforces the sidewalls 1 is anchored in each bead B at at least one bead wire, in this case of the “braided” type 3, so as to form turn-ups 4 that are separated from the main part of the carcass reinforcement by profiled elements 5 having a quasi triangular shape.
It is important to note that the invention can be implemented with a large number of types of tire, be they radial tires or diagonal tires, or even with tires of the type having self-supporting sidewalls.
The rim J comprises a groove 6, known as a mounting groove, that connects, on either side of the equatorial plane, two rim seats 7 that are axially extended by rim flanges 8, the radially outer edges of which are curved.
The adapter A mainly comprises an axially outer end 9, an axially inner end 10 and a body 11 connecting said end 9 to said end 10.
The axially outer end 9 comprises an outer reinforcer element 15 made up of a first portion 20a that is connected to a second portion 20b that form a substantially perpendicular angle between one another. During the mounting of the tire, the bead seat of the bead B is fitted into the space created by this outer reinforcer element 15.
The adapter A, which is disposed at each bead B of the tire, may be symmetrical or non-symmetrical. Symmetry means that the overall length of the body 11 is identical on both adapters. When the assembly (tire, rim and adapter) is mounted, the beads B of the tire are disposed on the adapter seat 14 and made to bear axially against a bearing face 21.
The body 11 comprises a substantially cylindrical adapter seat 18 that is intended to receive a bead of the tire (see
The body 11 also comprises an adapter bearing face 21 that is contained substantially in a plane perpendicular to the rotation axis, is situated on the axially inner face of the axially outer end, and is intended to keep the bead in place in its housing. This adapter seat 18 comprises an annular seat reinforcer 19 that has a compression modulus equal to 100 GPa. According to the depiction in this
In contrast to the known device (
The reinforcer 19 is made up of a tri-layer comprising metal reinforcers in the form of wires, alternating with an elastomer of the rubber-resin type. The reinforcer 19 has a radial thickness of about 1.5 mm and an axial length of about 15 mm.
The elastomer layer of the reinforcer 19 has a radial thickness of about 0.3 mm and an axial length of about 15 mm.
A layer of elastomer 20 covers all of the elements that make up the adapter, namely the reinforcer 15, the reinforcer 16, the body 11 and the radially outer surface of the reinforcer 19.
The following examples show the results obtained with the adapter according to the invention.
This test consists in causing a mounted assembly to mount a kerb at an angle of attack of 30°. The choice of this angle is based on the fact that it constitutes very harmful stress for a tire. The test is carried out with two different kerb heights (90 mm and 110 mm).
The test proceeds as follows. Several passes of the wheel at different speeds are carried out until the tire is punctured. The starting speed is 20 km/h and then the speed is incremented by 5 km/h on each new pass.
A conventional assembly without an adapter (control 1) is compared with an assembly provided with an adapter according to the document WO00/78565 (control 2) and with an assembly provided with an adapter according to the invention (invention).
These assemblies are all of the size 205/55R16 comprising a 6.5J16 rim. The results are collated in the following Table I and are given in percent:
Results greater than 100 show an improvement in behaviour when subjected to a lateral impact.
The test carried out at the kerb height of 90 mm led to the puncturing of the control tire at a speed of 30 km/h, whereas the assembly according to the invention did not suffer any damage at the same speed, or even at a speed of 50 km/h.
The test carried out at the kerb height of 110 mm led to the puncturing of the control tire at a speed of 20 km/h, whereas the assembly according to the invention did not suffer any damage at the same speed, or even at a speed of 50 km/h.
| Number | Date | Country | Kind |
|---|---|---|---|
| 1362970 | Dec 2013 | FR | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2014/078176 | 12/17/2014 | WO | 00 |
