阅读说明：本技术 具有轮辋的滚动组件，该轮辋的凸缘形成轴向宽度增加的支撑件 (Rolling assembly with rim whose flanges form a support of increased axial width ) 是由 D·瓦尔泽 B·韦迪 于 2018-06-29 设计创作，主要内容包括：本发明涉及一种滚动组件,其包括轮胎(2),所述轮胎(2)具有两个胎圈(21)、轮辋(3)和至少一个柔性延长件(1),所述柔性延长件(1)用于在胎圈(21)的一个与轮辋(3)之间提供连接,所述轮辋具有轮辋凸缘(32),所述延长件(1)包括轴向内端部(10)、轴向外端部(11)和主体(12),所述主体(12)主要在轴向上定向并且设置在所述轴向外端部(11)和所述轴向内端部(10)之间,所述轴向内端部(10)固定在所述轮辋上,所述延长件(1)具有用于容纳轮胎(2)胎圈(21)的延长件座(13),所述延长件座通过肩部在轴向上朝向外部延伸,所述肩部将所述轮胎(2)胎圈(21)轴向地固定,所述轮胎(2)胎圈(21)在胎圈(21)与延长件座(13)的交界处具有轴向宽度WB,其特征在于,所述轮辋凸缘(32)在胎圈(21)下方轴向地延伸距离S,使得比率S/WB大于0.1。(The invention relates to a rolling assembly comprising a tyre (2), said tyre (2) having two beads (21), a rim (3) and at least one flexible extension (1), said flexible extension (1) being intended to provide a connection between one of the beads (21) and the rim (3), said rim having a rim flange (32), said extension (1) comprising an axially inner end (10), an axially outer end (11) and a body (12), said body (12) being mainly oriented axially and being arranged between said axially outer end (11) and said axially inner end (10), said axially inner end (10) being fixed to said rim, said extension (1) having an extension seat (13) intended to receive the bead (21) of the tyre (2), said extension seat extending axially towards the outside by means of a shoulder which axially fixes the bead (21) of the tyre (2), the tyre (2) bead (21) having an axial width WB at the interface of the bead (21) and the extender seat (13), characterized in that the rim flange (32) extends axially below the bead (21) by a distance S such that the ratio S/WB is greater than 0.1.)

1. A rolling assembly comprising a tyre (2), said tyre (2) having two beads (21), a rim (3) and at least one flexible extension (1), said flexible extension (1) being intended to provide a connection between one of the beads (21) and the rim (3), said rim having a rim flange (32), said extension (1) comprising an axially inner end (10), an axially outer end (11) and a body (12), said body (12) being mainly oriented axially and being arranged between said axially outer end (11) and said axially inner end (10), said axially inner end (10) being fixed in position on said rim, said extension (1) having an extension seat (13) for housing the bead (21) of the tyre (2), said extension seat (13) extending axially towards the outside through a shoulder (111), the shoulder (111) axially fixing the tire (2) bead (21) in position, the tire (2) bead (21) having an axial width WB at the interface of the bead (21) and the extender seat (13), characterized in that the rim flange (32) has a radially outer bearing surface (33), the radially outer bearing surface (33) extending axially a distance S below the bead (21) such that the ratio S/WB is greater than 0.1.

2. Rolling assembly according to claim 1, wherein the ratio S/WB is smaller than 1.

3. Rolling assembly according to any one of the preceding claims, wherein the ratio S/WB is between 0.2 and 0.8.

4. Rolling assembly according to any one of the preceding claims, wherein the ratio S/WB is between 0.25 and 0.75.

5. Rolling assembly according to any one of the preceding claims, wherein the rim (3) has a rim seat (31), the rim seat (31) extending axially towards the outside by means of the rim flange (32); the axially inner end (10) of the extension piece is fixed in position by being axially pressed against the rim flange (32).

6. Rolling assembly according to any one of the preceding claims, wherein the radially external bearing surface (322) of the flange (32) of the rim (3) has a substantially frustoconical portion (322).

7. Rolling assembly according to claim 6, wherein the frustoconical supporting surface is oriented so that an imaginary vertex (S) determined by extending the frustoconical surface is axially external.

8. The rolling assembly of claim 7, wherein the frustoconical bearing surface has an angle α of between 5 ° and 30 °.

9. Rolling assembly according to any one of the preceding claims, having two identical extensions (1).

Technical Field

The subject of the invention is a rolling assembly consisting of a tyre, a rigid rim and a connection element interposed between the tyre and the rim via a flexible extension. As is known, a tire comprises two beads intended to be mounted on a bead seat. The present invention relates to rolling assemblies in which the beads are not mounted directly on a rigid rim, but on a flexible extension piece mounted on the rim.

The tire, rim and extension as discussed in the present invention are generally described by depiction in a mid-plane (i.e., a plane containing the axis of rotation of the tire). All these products (tires, rims, extensions) are objects with a geometry of rotation around their rotation axis. The radial direction and the axial direction respectively denote a direction perpendicular to the rotation axis of the tire and a direction parallel to the rotation axis of the tire. In the following, the expressions "radially" and "axially" mean "in the radial direction" and "in the axial direction", respectively. The terms "radially on the inside" and "radially on the outside" mean "closer to the axis of rotation of the tire in the radial direction" and "further away from the axis of rotation of the tire in the radial direction", respectively. A mid-plane is a plane perpendicular to the axis of rotation of the tire, which is axially positioned to intersect the surface of the tread substantially midway between the beads of the tire. The terms "axially on the inside" and "axially on the outside" mean "closer to the median plane of the tire in the axial direction" and "further from the median plane of the tire in the axial direction", respectively. The terms "radially on the inside" and "radially on the outside" mean "closer to the axis of rotation of the tire in the radial direction" and "further away from the axis of rotation of the tire in the radial direction", respectively. Finally, it should also be recalled that "radial cross section" or "radial section" means a cross section or section in a plane containing the axis of rotation of the rim (and of the tyre with which the rim is equipped).

Background

Document WO2016/046197 proposes the insertion of a flexible extension between the bead of the tire and the rim. For example, the reader may refer to fig. 5 of this document in order to familiarize himself with scrolling components that are within the field of the present invention. He will see therein a rolling assembly comprising a tire, a rim and two identical extensions. In view of the above-mentioned language convention, and with reference to the manner of mounting such an extension on a rim, such an extension comprises, from the inside to the outside in the axial direction, axially inner ends for fixing the extension to the rim, called extension beads. Such an extension piece also comprises an axially outer end for receiving the tire bead and axially fixing it in place. The body connects the axially inner end and the axially outer end.

The extension is mounted on a rim, which is most of the time an aluminium part. The rim has a rim flange on each side, which rim flange is used in particular to axially fix the extension piece in place. Another function of the rim flange is to deform the extension to form a boss (commonly referred to as a "bump" for the rim) where the tire intersects when inflated (as in a conventional tire and rim assembly without the extension). The boss helps to prevent or delay the detachment of the tire from the bead seat if the tire is used under an abnormally low inflation pressure (it is known that the guiding ability of the tire is greatly reduced in the case of detachment from the bead seat, and even loses the guiding ability when the tire falls off from the rim; the tire becomes highly likely to fall off from the rim).

During the exploratory studies, the "B" type flange (height 14.1mm +/-0.6) described with ETRTO was chosen as the radial height of the rim flange for rolling assemblies with extensions, whereas the flanges of passenger vehicle tires were typically "J" type (height 17.3mm +/-0.6). Although such a B-shaped flange, which is referred to in this document as a higher flange, has the advantage of contributing to a good disengagement value from the bead seat of a conventional tire/rim assembly (at low pressure), problems can also arise in the case of an installed extension.

First, the bulge is large enough that the inflation pressure value is too high to allow easy fitting of a tire mounted on a rim with an extension. Secondly, the flange deforms the extension substantially at the location where it hangs radially from the extension. In particular, in a completely unstressed state, the natural shape of the extension when it leaves the die is approximately cylindrical (in fact very slightly conical), with a diameter much smaller than that measured at the apex of the metal flange. The fitting of the extension piece thus causes a large local radial deformation of the extension piece. Since the reinforcements within the extension are typically of the "cross-ply" type at this location, the extension is highly resistant to such deformation. This results in a higher pressure between the extension piece and the metal flange at the location of the boss compared to a conventional rim bead.

Due to the good adhesion between rubber and aluminium, it is easy to understand that some of the axial loads generated by the tyre under pressure and tending to axially stretch the extension react locally at this interface, while all of these loads are preferably reacted by the root of the extension on the metal flange in order to ensure a balanced mounting of the extension. As in the present case, since the entire edge of the extension piece is not necessarily mounted exactly the same, the fact that the position of the extension piece is not well defined leads to irregularities in the geometry, which in turn leads to vibrations during rolling due to non-uniformities.

The applicant's observations have thus led to deviations from the usual rim construction rules.

Disclosure of Invention

It has surprisingly been found that this object is achieved by deviating from the prior art according to which the tire bead should not project radially beyond the rim.

The subject of the invention is therefore a rolling assembly comprising a tyre having two beads, a rim with a rim flange and at least one flexible extension for providing a connection between one of the beads and the rim, the extension comprising an axially inner end, an axially outer end and a body oriented mainly in the axial direction and arranged between the axially outer end and the axially inner end, the axially inner end being fixed in position on the rim, the extension having an extension seat for housing a tyre bead, the extension seat extending axially towards the outside by means of a shoulder that axially fixes the tyre bead in position, the tyre bead having an axial width WB at the interface of the bead with the extension seat, characterized in that the rim flange has a radially outer bearing surface, the radially outer bearing surface extends axially below the bead by a distance S such that the ratio S/WB is greater than 0.1.

According to the prior art, the extension mounted on the metal rim actually forms the seat of the tyre, in terms of its ability to absorb impacts radially. They impart greater radial flexibility to the rolling assembly. Although it was thought in the past that this ability to absorb shocks could not be significantly improved if the beads of the tyre were not located completely outside the rim in the axial direction, it has been found that by planning the inclination of the beads of the tyre and the radial displacement towards the axis of rotation of the rolling assembly, it is possible to maintain both a certain radial flexibility and an excellent durability of the extension and an improved road holding performance (which is known to be better when the tyre is capable of generating high drift thrusts that favour a strict lateral steering of the vehicle). The extension of the radially outer bearing surface of the rim flange under the bead of the tire enables to effectively improve the road holding performance of the rolling assembly, compared to the rolling assembly geometry proposed, for example, in the cited document WO 2016/046197.

The invention gives the rim a new function of tightening the shape of the extension more or less, thanks to the presence of a rigid bearing surface radially below the toes of the beads of the tyre, providing a rigid support which, when considering the axially outermost part of the beads, forces the tyre to start a tilting movement which cannot counteract a sufficient radial displacement of the beads.

Preferably, the ratio S/WB is less than 1.

This is because, above 1, the observed improvement in the guiding capacity of the rolling assembly is no longer significant and the performance in terms of impact resistance may no longer be optimal.

Preferably, the ratio S/WB is between 0.2 and 0.8, and highly preferably between 0.25 and 0.75. This enables the rolling characteristics of the rolling assembly to be optimised optimally, while maintaining a significant resistance to impacts in the radial direction (for example curb or pothole impacts).

Preferably the radially outer bearing surface of the rim flange has a substantially frusto-conical portion, advantageously the frusto-conical bearing surface has an angle α of between 5 ° and 30 °.

Observations have shown that the performance in terms of resistance to impacts in the radial direction is comparable to or even better than that obtained by applying the teachings of the prior art. Preferably, the rolling assembly has two extensions providing the connection between the mounting rim and the two beads of the tyre.

Each elongate member is flexible; this is understood to mean that it is elastically deformable, as seen in meridian section, allowing bending and radial displacement without leaving the elastic region under the application stress loads during use of the tyre inflated to nominal pressure. It should be noted that during normal operation of the tire when inflated to nominal pressure, axial deformation of the extension is almost negligible.

The constituent material of the rim is preferably selected from the following materials: steel or alloys of aluminium and/or magnesium, composite materials based on carbon fibres, glass fibres, aramid fibres, vegetable fibres contained in a matrix based on a thermosetting or thermoplastic compound, or composites based on an elastomer and on a resin and fibres selected from carbon fibres, glass fibres, aramid fibres, vegetable fibres or any combination of materials.

For other aspects of the rim itself or of the extension itself, the reader is referred to the above documents WO2015/086662 and WO 2016/046197.

Drawings

The invention is described below with reference to fig. 1 to 7, which fig. 1 to 7 are given by way of example only:

figure 1 is a meridian section of a rolling assembly with a rim according to the invention,

figure 2 is an enlarged view of the left part of the assembly,

figure 3 is a partial meridian cross-section of a rim according to the invention,

figures 4 and 5 show the kerbstone resistance test in side view and top view respectively,

figure 6 shows the performance results of the rolling assembly according to the invention in a kerbstone test,

figure 7 is a partial meridian cross-section of another embodiment of the rim according to the invention.

Detailed Description

Fig. 1 shows a rolling assembly according to the invention. The assembly comprises two identical elongate members 1, a tyre 2 and a rim 3. The tire 2 has two beads 21. Generally, it should be noted that the rim width is chosen so that, given the width L of the extension (see fig. 2), the configuration of the tire is as similar as possible to what it would have if it were mounted directly on the appropriate rim without the extension.

With more particular reference to fig. 3, it is evident that the rim 3 has two rim seats 31, each rim seat 31 extending through a rim flange 32, the rim flange 32 having a radially outer bearing surface 33, the radially outer bearing surface 33 being intended to serve as a support for the body of the extension, the bearing surface 33 of the rim flange 32 being in contact with the extension 1 when the tyre is mounted on the extension and the extension is mounted on the rim, the tyre being inflated to a nominal pressure, the bearing surface 33 having a first portion 321, the first portion 321 being substantially oriented in a plane perpendicular to the axis DD' of rotation of the rolling assembly and being radially outer with respect to said rim seat 31, the bearing surface 33 of the rim flange 32 having a second portion 322 of substantially frustoconical shape, the second portion 322 being axially outer with respect to said first portion 321 and being at least partially radially outer with respect to said rim seat 31, said second portion 322 being substantially frustoconical, the angle α being 15 °, the bearing surface 33 also comprising the connecting portion between said first portion 321 and said second portion 322, the axial width WR of the rim flange 32 being 18.3 mm.

Reference numerals E and I in fig. 3 denote the axially outer side and the axially inner side of the rim, respectively. The second portion 322 slopes axially outward: thus, by extending it axially towards the outside, the second portion 322 intersects the axis DD' (in a position not proportional to the rim 3) at an imaginary vertex S, which is located at a very far distance axially towards the outside, indicated by the arrow below S in fig. 3.

The invention can be used with many variants of the internal configuration of the tyre 2, not shown, and with many variants of the internal configuration of the extension 1, not shown.

Returning to fig. 2, it is evident that each extension piece 1 has an axially inner end 10 intended to be mounted on one of said rim seats 31. It has an axially outer end 11 and a body 12, which body 12 is substantially axially oriented and arranged between said axially outer end 11 and said axially inner end 10. The body 12 has a radially inner surface 122. The axially inner end 10 of the extension has an axial positioning face 101 substantially perpendicular to the rotation axis D-D' and is fixed in position by axial pressing against the rim flange 32 under the effect of the inflation pressure of the rolling assembly. The axially outer end 11 has a shoulder 111, which shoulder 111 partially forms a face substantially perpendicular to the rotation axis DD'. The extension 1 has an extension seat 13. The bead 21 has an axial width WB at the interface of the bead 21 and the extender seat 13. The beads 21 are fixed in position by being pressed axially against said axially outer end 11 of the extension under the effect of the inflation pressure of the rolling assembly.

Extending radially inwards the trace (trace) line of the shoulder 111 of the axially outer end 11 and the trace of the extender seat 13, obtaining a point of diameter D₁Which diameter itself corresponds to the standard diameter of a tyre using the rolling assembly of the extension piece 1 according to the invention. Extending the trajectory of the axial positioning surface 101 radially inwards and of the rim seat 31, a point is obtained which is of diameter D₀The diameter being the nominal diameter of the rim seat 31. For information on the standards referred to, the reader should consult the document of the ETRTO (european tyre and rim technical organisation). The height of the rim flange, measured between the intersection point between the trajectory of the rim seat 31 on the one hand and the trajectory of the radial portion 321 of the flange 32 and the radially outermost point F of the flange 32 on the other hand, is 8.5mm (see fig. 7). This makes it possible to obtain a projection of the extension suitable for retaining the bead of the tyre on the extension seat without causing excessive stresses in the structure of the extension.

Once the mounting is completed, the beads of the tyre cause a circumferential contraction of the extension 1. The rim flange 32 extends axially below the bead 21 by a distance S such that the ratio S/WB equals 0.3. It is therefore evident that the radially inner surface 122 bears on the radially outer bearing surface 33 of the rim flange 32 over its entire axial width WR, which is 18.3mm and much greater than the known embodiments, forcing the beads 21 of the tire to tilt in a rotational movement (in the anticlockwise direction for the side of the tire 2 shown in fig. 2) when the beads 21 of the tire are subjected to a load that increases significantly in the radial direction.

Figure 7 shows a partial meridian cross section of an alternative embodiment of a rim according to one of the subject-matters of the present invention. The same reference numerals correspond to the same or similar parts.

The rim 3 differs from the rim shown in fig. 1 in that it has a rim seat 310, which rim seat 310 is substantially cylindrical between two transition areas 311 and 312 and has a much smaller axial width P, of the order of 15.3 mm. These two modifications make it possible, when the extension 1 is mounted on the rim, to lock the extension bead of the extension 1 in its position of use, without relying on the inflation pressure of the rolling assembly when the tire is mounted on the rim and extension assembly.

The curb resistance is measured by passing the rolling assembly over a 50 to 90mm tall curb at an angle β of 60 relative to the direction of forward travel of the tire (90 angle corresponding to the direction perpendicular to the direction of travel of the tire, see FIGS. 4 and 5), the edge of the curb has a radius of curvature of 10mm, passing successively at different speeds until the tire loses inflation pressure or until the tire or extension or wheel is permanently deformed and a force is obtained on the vehicle that is transmitted to the curb and/or hub on each pass245/35R20 tire model PS4S and rim width of 8 inches, the flange being a J-flange. As shown in fig. 4, the wheel 4 of the rolling assembly tested was a wheel with spokes 42.

Four rolling assemblies with extensions were tested with variable values of the ratio S/WB:

the first E1 has a rim as shown in FIG. 3, with a ratio S/WB equal to 0.27;

the second E2 has a rim as shown in FIG. 7, with a ratio S/WB equal to 0.27;

the third E3 has a rim as shown in FIG. 7, with a ratio S/WB equal to 0.49;

the fourth E4 has a rim as shown in FIG. 7, with a ratio S/WB equal to 0.70.

Fig. 6 shows the results of the kerb test.

The x-axis of the graph in fig. 6 represents the speed of forward movement of the tyre, in km/h, and the y-axis represents the maximum value of the radial load measured on the ground during an impact, in daN.

The controlled rolling assembly T1 without extension exhibited sidewall bulges in the 18km/h test and perforations in the 20km/h test.

For four rolling assemblies with extensions, no tire damage occurred over the entire tested speed range, even though the maximum value of the radial load increased significantly with speed.

It should be noted that the maximum value of the radial load varies significantly depending on the location of the impact on the wheel. If the impact occurs on a spoke of the wheel, Fz is higher than if the impact occurs between two spokes.

Therefore, the results of these four components cannot be distinguished; it should be noted, however, that even if an increase in radial load occurs with an increase in the value of the ratio S/WB, the increase in the ratio S/WB does not reduce the resistance of the rolling assembly to the kerbstone.

For the rolling assembly E1, a permanent deformation of the wheel at the impact location was observed starting at 42 km/h. The optimal resistance of the three other rolling assemblies according to the invention may be related to the change in geometry of the rim flange and the extension towards the outside of the rim flange.

In contrast, during the running test, it was observed that the driving accuracy was significantly improved as the S/WB ratio was increased.

The rolling assembly according to the invention thus makes it possible to improve the steering of the vehicle very significantly, while maintaining a very good resistance to impacts.