EP1951532A2

EP1951532A2 - Flexible non-pneumatic tyre

Info

Publication number: EP1951532A2
Application number: EP06819442A
Authority: EP
Inventors: Marc Sebe
Original assignee: Michelin Recherche et Technique SA Switzerland; Michelin Recherche et Technique SA France
Current assignee: Michelin Recherche et Technique SA Switzerland; Michelin Recherche et Technique SA France
Priority date: 2005-11-15
Filing date: 2006-11-13
Publication date: 2008-08-06
Also published as: CN101309805A; US20090250149A1; FR2893274A1; WO2007057374A2; JP2009515764A; WO2007057374A3; FR2893274B1

Abstract

The invention relates to a flexible non-pneumatic tyre (1) comprising a plurality of support elements (2) which are connected to one another by means of an interconnection structure (3) which supports a tread (4), each support element being connected to a rim (6) by a clamp (7).

Description

Non-pneumatic flexible tire

The present invention relates to vehicle wheels using flexible tires designed to be able to carry a substantial load without inflation pressure, these tires being commonly called non-pneumatic tires.

The patent application WO 00/37269 proposes such a non-pneumatic flexible tire. It describes a bearing structure essentially comprising a plurality of support elements arranged substantially radially, in a cyclic symmetry around the circumference of the bandage. When the bandage described in patent application WO 00/37269 carries a load, a certain number of support elements present in the contact area are subjected to a large bending, which allows them to develop a recovery effort. part of the load. An interconnection structure makes the support elements work together, transferring the stresses to the adjacent support elements. The ability of this bandage to carry a certain load thus comes from the bending stress of the support elements present in the contact area of the non-pneumatic elastic bandage, and it also comes from the stressing also in bending of the support elements. outside the contact area of the non-pneumatic elastic bandage, via the interconnection structure.

The patent application EP 1 359 028 proposes a bandage of this type whose interconnection structure is connected to the support elements by elastic joints. The present invention relates in particular to the connection in the tire fixing area of the support elements with a rigid element intended to be secured to the vehicle hub during normal use of the tire.

An object of the invention is to provide a simple connection, accurate, reliable and compatible with an industrial production and assembly of flexible tires.

The invention proposes a flexible tire comprising: a plurality of support elements juxtaposed circumferentially and distributed around an axis of rotation of the tire to form a supporting structure,

A tread at the radially outer periphery of the bearing structure, the bearing structure comprising at least one attachment zone, radially on the rotation axis side, for the immobilization of said bearing structure on a rim, said tread flexible being characterized in that said rim is annular and that each support member is secured to the rim by means of a jumper crimped in substantially axial slots of the rim.

Preferably, the jumper consists of a metal sheet folded so as to match the profile of the corresponding support member in the fastening zone.

Preferably, the legs of the rider extend through the slots of the rim radially inwardly, the ends of said legs forming tabs folded against the inner wall of the rim. Preferably, the rider is crimped in slots respectively common to the two adjacent riders circumferentially.

Preferably, each rider is crimped by means of at least four tabs in at least four slots of the rim, more preferably, through at least six tabs in at least six slots of the rim. rim.

Preferably, the support elements comprise a stack of flexible blades and layers of a polymeric composition.

[0012] Preferably, the support elements have a closed ovoid shape.

Preferably, each jumper is secured to the corresponding support member via said polymeric composition.

The invention also relates to a wheel web capable of rigidly connecting the tire to a hub, said web comprising fixing means adapted to cooperate with the rim.

The invention is described in more detail by means of the following figures, in which:

• Figure 1 is a partial perspective of a non-pneumatic tire;

FIG. 2 is a partial section along BB of a first embodiment of the invention; FIG. 3 is a partial section along CC of a second embodiment of the invention;

FIG. 4 is a detailed view of an embodiment of the fixing zone according to the invention;

FIG. 5 is a partial section along the plane A-A of FIG. 4;

FIGS. 6 and 7 are perspective views of a jumper according to the invention before and after crimping;

The 8 to 1 1 show different embodiments of the jumper according to the invention;

• 12 to 14 show in section according to A-A two embodiments of the bandage assembly method according to the invention;

FIGS. 1 to 18 show in section along B-B two embodiments of a wheel according to the invention.

In the different figures, identical or similar elements bear the same references, their description is not systematically repeated. These figures are given for illustrative and not limiting.

Figure 1 shows the general appearance of a flexible bandage 1 according to the invention. Such a tire, when combined with any other rigid mechanical element intended to ensure the connection between the flexible tire and the hub, replaces the assembly constituted by the tire and the wheel as known on most vehicles. roadways. The bandage profile delimits a toroidal internal cavity of ovoid section. The tire 1 comprises a fastening zone 5, two sidewalls 12 and a tread 4. The fastening zone is intended to be rigidly connected to the wheel hub via a mechanical element such as a disk or wheel sail. (not shown here) In this FIG. 1, the tread 4 comprises several circumferential ribs, but this aspect of course has no limiting character. The flanks 12 are rounded and occupy most of the radial height of the bandage 1. The supporting structure comprises a plurality of support elements 2. The support elements are circumferentially adjacent and each extends substantially radially outwardly from the attachment zone 5. FIG. 1 also shows a principle of this type non-pneumatic tire according to which it is the bending of the support elements that makes it possible to carry the load. In this particular example, the bandage comprises a hundred support element 2. This number can of course be very different depending, for example, on the type of vehicle and the type of use for which it is intended and the characteristics of the support elements. . The number of elements can thus vary for example from 30 to 300.

[0018] Figure 2 shows a first preferred embodiment of the invention. The support elements 2 comprise a stack of blades 21 of composite material, flexible, radially superimposed with interposition between the blades 21 of a layer 22 of polymer or a polymeric composition, especially diene elastomer or polyurethane. The bond between the composite material and said polymer being obtained in a known manner, in particular during the baking operation, polymerization or final crosslinking of the assembly, if necessary using an adhesive composition adapted to the nature of the polymer for example as described in WO 04/058909.

A mechanical preparation (for example by sanding) and / or chemical (for example by the use of an acidic agent) of the surface of the blades can be advantageous for improving the bond between the blades 21 and the intermediate layers 22 .

The beam of blades thus glued on each other forms a beam capable of being stressed mainly in bending. Preferably, each flexible blade 21 is closed, ie it extends all around the bandage section and is not interrupted. The stack shown here comprises five blades. This aspect of the constitution of the laminate is however not limiting.

Preferably, an interconnection structure 3 disposed radially under the tread 4 connects circumferentially all of the support elements. The interconnection structure 3 is relatively rigid in longitudinal tension-compression.

For further details on the constitution of these support elements and the interconnection structure, the reader can usefully refer to the aforementioned patent applications WO 00/037269 and EP 1 359 028.

Just remember that the composite material of the blades 21 comprises reinforcing fibers embedded in a resin. A thermosetting resin matrix is preferably used, but in some less demanding applications a thermoplastic resin may be suitable. The fibers are preferably arranged mainly longitudinally in each blade. For example, glass fibers are used. Of course, many other fibers could be used, such as carbon fibers. One could also use a hybrid prepared with fibers of different natures.

The designation "fixing zone" is used to designate in general the portion 5 of the tire intended to cooperate with a rigid mechanical part which is otherwise integral with the hub.

[0025] Figure 2 shows an embodiment of the invention whose profile is particularly suitable for the equipment of a 4-wheeled passenger vehicle. In this embodiment, the support members 2 are closed. The flanks 12 of the bandage comprises, at the level of the equator E, protective bulges 13, for example consisting of a polymer similar to that of the layer 22 interposed between the flexible blades 21. The tread 4 is bonded to all of the support elements via the interconnection structure 3 and elastic hinges 23.

According to the invention, the fastening zone 5 is embedded (that is to say rigidly bound) on an annular rim 6. In this example, the fastening zone is axially centered with respect to the tire (see the position of the tire). jumper 7 with respect to the median plane 8 of the bandage). The bandage comprises a large number of such support elements 2 as is clearly visible in FIG.

Each support member 2 rests on the periphery of the rim 6 and is connected to the rim via a jumper 7. The rider is fixed both radially, axially and circumferentially opposite the rim. Preferably, the attachment is made by crimping (alternatively, the attachment could be made by welding). The crimping operation consists of folding the ends of the tongues 10 of the legs 9 of the rider against the inner wall 1 1 of the rim. The ends of the legs are in fact foldable tongues (this aspect is however better visible in Figures 5 to 7). The riders 7 (as numerous as the support elements 2) are then juxtaposed to each other along the circumference of the rim. Preferably, the number of support elements (and therefore the number of jumpers) is such that the riders bear circumferentially on each other (this preferred aspect is best seen in Figures 4 and 5). One can alternatively provide a certain gap between the jumpers, this gap being or not filled by spacers.

A main function of the rim 6 is to join together the support elements at their attachment area. The rim can then be attached directly or indirectly to the wheel hub (not shown).

Figure 3 shows another embodiment of a flexible tire wheel according to the invention. In this figure, the profile of the bandage 1 is adapted to its use for a two-wheeled vehicle such as a motorcycle or scooter. The main elements constituting the bandage are identical or similar to those of FIG. 2. However, the support elements 2 here comprise four blades 21 made of composite material and three intermediate layers 22. The annular rim 6 is also reduced compared to that of the FIG. 2. This rim is intended to be connected to the wheel hub via a rigid element such as a wheel web 25 and not directly as is possible with the rim of FIG. 25 (shown only in part) is intended to fix the rotating assembly on a hub (not shown) of the vehicle. The sail comprises fixing means adapted to cooperate with the rim. In this preferred example, the rim is clamped between a fixed jaw 26 and a removable jaw 27 of the web 25. The removable jaw 27 can be held in place by any fastening means such as rivets or screws 28. The fixed jaws 26 and removable 27 are preferably circular and monobloc although they may also consist of a plurality of arcs, spaces being left or not between the arches.

In this sectional view, we can see the tabs 10 folded against the inner wall 1 1 of the annular rim.

Figures 4 and 5 show the juxtaposition of the support elements 2 on the rim 6. For clarity of the drawings, there is shown only a portion of the annular rim and three support elements held on the rim by their three riders . Figure 4 shows the attachment zone 5 from the inside of the tire seen in a radial direction. One can well visualize the axial slots 1 3 in which the jumpers are inserted to be fixed to the rim. Each slot preferably receives the legs of two adjacent riders. Here is shown the section plane BB corresponding to the view of Figure 2 and the section plane CC corresponding to the view of Figure 3. Figure 5 shows the same sectional attachment area in a plane (AA in Figures 2 to 4) parallel to the median plane of the bandage. In particular, we see the general radial orientation of the support elements and the crimping principle of the riders. We also see the principle that the riders are shaped to fit the shape of the support elements. According to a preferred form, the upper part of the riders comprises a central zone 71 intended to exert pressure at the center of the stack of flexible blades 21 and rounded folding zones 72 not exerting direct pressure on the stack. The folding zones 72 may receive a filling 73, for example consisting of the same composition as the intermediate layers 22. The jumper is preferably made of a cut sheet metal, preferably steel.

Figure 6 shows a jumper before crimping. Figure 7 shows the same jumper after crimping. This example corresponds to that of the previous figures. Each leg 9 of the rider has a notch 74 defining here two tabs 10 per leg (ie four tabs per rider). Each tongue is intended to be folded substantially at 90 ° during crimping. The indentation contributes to the axial retention of the rider on the rim and can also be used to introduce the polymer 22 between the flexible blades 21 (by injection, transfer, casting or other method known per se). The ends of the tabs can preferably be beveled as shown here (see bevels 75) to facilitate their insertion into the slots of the rim. The length of the slots can then be adjusted to the width of the tabs to make positioning and lateral support of the rider more precise without increasing the difficulty of mounting.

In Figures 8 to 1 1, there is shown various configuration examples of the jumper 7, each in its final position crimped on the rim 6. The corresponding support member is not shown. In Figure 8, each leg 9 of the rider 7 has four tabs 10 inserted into a corresponding number of slots 1 3 of the rim 6. The tabs are separated by three notches 74 similar to that of the previous figures.

The configuration of Figure 9 is similar to that of Figure 8 except that the side notches 76 have a length limited to the minimum necessary for fixing by crimping. The central notch 74 is identical to those of the previous figures.

In Figure 10, the rider has three tabs 10 per leg, the central tongue being here wider than the other two. The two indentations 74 are long.

In Figure 1 1, the rider has five tabs 10 per leg, the central tongue being here wider than the other four. All the indentations 76 have a length limited to the minimum necessary.

An advantage of increasing the number of tongues is that, for a given mechanical stress of the jumper-rim connection, the maximum local stresses are reduced. This is particularly true for the local stresses experienced by the rim due to the winding forces which tend to bend circumferentially the support elements relative to the rim.

On the contrary, the rider may have only one tongue per leg, that is to say do not include indentation, an advantage of this configuration being its great simplicity. In the examples mentioned here, the two legs of a jumper are identical or similar since they are preferably intended to cooperate with slots common to the adjacent rider within the bandage. However, if the slots are not shared by two jumpers (for example because the jumpers are distant from each other), the two legs of the jumpers may be different, both in terms of the number of tabs and the length of the (or indentations.

Figures 12 to 14 illustrate the principle of the crimping method of the riders on an annular rim.

In Figure 12, the rim 6 already has a support member 2 'crimped by a rider 7'. A new support element 2 and its rider 7 are placed radially. The slot 13 'which has already received the tongue 10' of the first rider 7 'then receives the tongue 10 (not yet folded) of the second rider 7. Once positioned, the rider 7 is crimped in turn on the rim 6.

In FIG. 13, the crimping is done in a single movement (radial towards the outside) of a punch 81. A counter-punch 82 can temporarily hold the jumper in place and even act against the movement of the punch 81 to place the stack of flexible blades under pressure.

The crimping can also be performed in two successive steps as shown in Figure 14. A clamp 83 acting in the circumferential direction of the bandage initially folds partially the tabs 10 before a finishing punch 84 comes to complete the crimping radial. Crimping can occur simultaneously on all the tabs of a rider or on a portion of them only (for example one by one or two by two). It is also possible to crimp several riders at the same time with the aid of adapted tools.

In addition to crimping, the attachment can be further reinforced by welding, for example by points, tabs folded against the inner surface 1 1 of the rim. Alternatively, the attachment of the riders to the rim could be achieved only by welding, without prior crimping. An attachment made only by crimping has in particular the advantage of not imposing significant thermal stresses.

The jumpers can be placed astride the support elements at the time of assembly of the bandage, that is to say immediately before crimping. The jumpers may also be placed during a pre-assembly operation, for example during molding of the support members. A preferred method for manufacturing a support member and for assembling with a rider comprises successively the following steps:

- prepare the flexible blades 21,

- arrange these flexible blades in a mold according to the desired arrangement in the support member 2,

have a jumper 7 straddling the stack of flexible blades in the desired position relative to the support element,

- Introducing a solid liquid polymer capable of forming the intermediate layers 22 and to secure the jumper to the stack and if necessary to form the fills 73 and the protective bulges 13.

- Submit the set to a solidification stage. The solidification may be obtained in known manner, for example by baking, cooling, crosslinking, polymerization.

In Figures 1 5 and 16, there is shown other embodiments of the rigid connection between the annular rim 6 and the wheel hub (not shown).

The example of Figure 1 5 uses an outer disc 61 and an inner disc 62 whose peripheries are crimped (and / or welded) on the edges of the annular rim 6. The two discs can also be made directly integral for example by welding.

The example of Figure 1 6 uses a rim in two parts 6a and 6b symmetrical. Each jumper 7 is here crimped into respective slots of the two parts 6a and 6b. The two parts 6a and 6b can be made integral (for example by welding or crimping not shown).

Thus we can bolt all on a hub in the same way as for a conventional wheel, for example with an offset "D" (see Figure 1 5) or without offset (Figure 16). It is also possible to use an additional intermediate element such as a wheel cover comparable to that described in FIG.

Figures 1 7 and 18 correspond respectively to Figures 1 5 and 1 6 and show more fully the assembly of the flexible tire wheel of the invention.

In general, the radially outer surface of the rim 6 according to the invention preferably constitutes a bearing surface for the support elements. This function is illustrated for example in FIGS. 2 to 5. Reference can be made to the description of the patent application WO 00/037269 and in particular to FIGS. 9 regarding the possibilities of dimensional variations of these bearing surfaces. It also includes the role of the rim profile and in particular its edges vis-à-vis the distribution of stresses in the support elements as a function of the load carried by the bandage.

Recall that the radially inner portion of the bearing structure, that is to say the part closest to the axis of rotation of the wheel, has a significant contribution to the arrow under load, so the comfort provided by the bandage. Therefore, it is appropriate that the fixing area is located, preferably on a fraction corresponding to at most 50% of the distance axially separating the lateral limits of the bandage. Said radially inner portion of the supporting structure is thus cantilevered enough pronounced beyond the fixing area. A favorable constructive arrangement is that the support elements are, just beyond the fixing zone, oriented in a direction substantially parallel to the axis of rotation of the bandage. This is shown in the examples described here. Note finally that, the bandages described being symmetrical, the fixing zone is substantially centered between the axial limits of the bandages, without this being limiting. One could of course adopt an asymmetrical architecture, especially in the location of the fixing area.

According to a variant of the invention, the support elements can also be open, ie interrupted, for example, as shown in FIGS. 8 and 9 of the patent application WO 00/037269 and in FIG. Patent application EP 1 359 028. In this case, the closure is provided by the jumper and the attachment means described above as well as, where appropriate, by the bonding polymer to the rider.

As seen, the profile of the annular rim can take different forms, particularly depending on its mode of connection, direct or indirect with the hub. The rim can for example be obtained by stamping sheet metal or by spinning. The rim is preferably made of steel. The slots intended to receive the tabs of the riders can in particular be obtained by machining, stamping or cutting (laser, water jet).

Claims

1. Flexible bandage (1) comprising:

A plurality of support elements (2) juxtaposed circumferentially and distributed around an axis of rotation of the tire to form a supporting structure,

A tread (4) at the radially outer periphery of the supporting structure, the bearing structure comprising at least one attachment zone (5), radially on the side of the axis of rotation, for the immobilization of said bearing structure on a rim (6), said flexible tire being characterized in that said rim (6) is annular and that each support element is secured to the rim by means of a rider (7) crimped in slots substantially axial (1 3) of the rim.

2. flexible tire (1) according to claim 1 wherein the rider (7) consists of a metal sheet folded so as to match the profile of the corresponding support member (2) in the attachment zone (5). .

3. Flexible tire (1) according to claim 2 wherein the rider's legs extend through the slots (1 3) of the rim radially inward, the ends of said legs forming tabs (10) bent against the wall inner (1 1) of the rim.

4. Flexible tire (1) according to one of the preceding claims wherein each jumper is crimped into slots (13) common respectively to the two adjacent riders circumferentially.

5. flexible tire (1) according to one of the preceding claims wherein each jumper is crimped through at least four tabs (10) in at least four slots (1 3) of the rim.

6. flexible tire (1) according to one of claims 1 to 4 which each rider is crimped through at least six tabs in at least six slots of the rim.

7. Flexible tire (1) according to one of the preceding claims wherein the support members comprise a stack of flexible blades (21) and layers (22) of a polymeric composition.

The flexible tire (1) of claim 7 wherein the support members have a closed ovoid shape.

9. flexible tire (1) according to one of claims 7 or 8 wherein each jumper (7) is secured to the corresponding support member through said polymeric composition.

10. Sail wheel (25) adapted to rigidly connect the tire (1) according to one of the preceding claims to a hub, said web comprising fastening means (26, 27, 28) adapted to cooperate with the rim (6). ).

1 1 .Wheel with flexible tire comprising a tire according to one of claims 1 to 9 and an annular rim (6), characterized in that each support element is secured to the rim by means of a rider ( 7) crimped in substantially axial slots (1 3) of the rim.