Abstract:
The present invention relates to a run-flat device for attaching a tubeless mounted assembly for a motor vehicle, and to such a mounted assembly incorporating said device. A device ( 30 ) according to the invention includes: a tire support structure ( 30 ), to be mounted around a rim having a plurality of pieces and comprising a reinforcing frame, and a bead lock means for locking the beads against the rim edge and connecting the support structure to the beads. According to the invention, the frame comprises an axial belt having at least one pair of ends opposite each other, separated by a connecting axial interstice, and connected therebetween by detachable connecting means ( 35, 36 ) for locking the belt, the support structure being radially split on both sides on the right of each interstice to enable the manual mounting of the device inside the casing by the gradual insertion therein of the structure, temporarily free of the connecting means.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a run-flat device intended to be fitted to a tubeless mounted assembly for a motor vehicle, to such a mounted assembly incorporating this device which allows a significant distance to be covered at a relatively high speed when the mounted assembly is partially or fully deflated, and to a method of manufacturing and of assembling this mounted assembly. This run-flat device is intended to be mounted on a multi-block rim and the mounted assembly incorporating it is notably usable for fitting to a military vehicle intended to travel over all kinds of terrain including sandy terrain. 
     BACKGROUND OF THE INVENTION 
     Known run-flat devices for multi-block rims generally consist of an annular supporting structure which is mounted around the rim inside a tire cover and which is equipped with means of locking the beads of the cover against the flanges of the rim, such as annular wedges that connect the annulus to these beads. 
     Document EP-A-1 900 551 in the name of the Applicant Company describes such a device in which the supporting structure is split into annulus sectors, each comprising rigid supporting elements that are superposed and separated from one another two by two by an elastic layer consisting, for example, of a rubber/metal reinforcement composite in the form of an arc of a cylinder so that a relative axial movement of the sectors is permitted by the shearing of this layer under a lateral force applied to the structure. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a new run-flat device for a tubeless mounted assembly for a motor vehicle, which comprises a wheel rim in several blocks and a tire cover comprising beads mounted against flanges of this rim, this device comprising:
         an annular supporting structure which is intended to be mounted around the rim so as to support the cover following a drop in inflating pressure inside the mounted assembly, and which comprises a reinforcement, and   locking means for locking the beads against the rim flanges and which are intended to connect the annular supporting structure to the beads,
 
which device can notably be mounted manually inside the cover while at the same time satisfactorily performing the run-flat function and the function of holding the beads in position.
       

     To this end, a device according to the invention is such that the reinforcement comprises an axial belt having at least one pair of opposing ends separated by an axial connecting gap and connected together by removable connecting means for fastening the belt, said supporting structure being split right through radially in line with said or each gap so as to allow the device to be mounted manually inside the cover by gradually inserting into said cover the structure which is temporarily devoid of the connecting means. 
     As will be explained hereinbelow, these removable connecting means fitted to the axial belt (i.e. running overall in the direction of the axial width of the supporting structure) allow the split structure to be closed up from inside the cover by fitting and fastening these connecting means in order to tighten the belt. 
     According to another feature of the invention, said locking means may advantageously be formed as a single piece with said supporting structure, and they then preferably comprise two lateral protrusions extending axially one on each side of a radially interior zone of said supporting structure and substantially facing said belt. 
     It will be noted that the belt of the run-flat device according to the invention is advantageously designed both to confer upon the supporting structure incorporating it satisfactory ability to withstand the centrifugal effects encountered during driving, and also to provide a “beadlock” effect whereby the beads of the tire cover are locked against the rim flanges. 
     According to another feature of the invention, said removable connecting means may advantageously comprise at least one connecting flange which is fixed removably on a radially internal face of said supporting structure by fasteners, such as screws, which are inserted into this flange passing through the two ends of said or each corresponding pair of the belt. 
     It will be noted that the space between the two ends of the or each pair is dictated by the dimension that the connecting flange has in the circumferential direction when fixed under the belt, and that the or each connecting flange may allow adjustment of the inside diameter of the run-flat device. 
     Advantageously, said or each connecting flange may have a central projection extending in the axial direction at right angles to the fixing face of the flange, this projection being intended to sit in said gap and being designed to minimize the bending work of the or each corresponding flange (which in this instance is in the shape of a T). 
     Advantageously, also, each of said ends of the belt may comprise at least one support plate through which said fasteners are intended to pass and which extends radially projecting in relation to the remainder of the belt, which is preferably provided with a balancing weight diametrically opposite said support plates in order to minimize the out-of-balance under running conditions. 
     It will be noted that this balancing weight, which may be provided on the radially internal and/or external face of the belt, can preferably be used in the case of a supporting structure that is in a single piece and split. 
     According to another feature of the invention, said or each connecting flange preferably fits into a cavity which is formed in said internal face of the supporting structure and which is centered on said or each corresponding gap of said belt so that this flange is accessible via this internal face while for example being substantially level therewith. 
     According to another feature of the invention, said supporting structure may be compression-molded or injection-molded in at least one elastomeric or thermoplastic material, respectively, at least the radially external face of the structure intended to support the cover preferably being made of an elastomeric material. 
     Advantageously, this supporting structure may be obtained by overmolding said belt with an elastomeric or thermoplastic material so that this material radially and axially surrounds said belt, forming said or each cavity, for example by using an overmolding insert placed in the mold. 
     According to a first embodiment of the invention, the supporting structure forms a one-piece ring which is split right through in a single location on its circumference, which location is situated radially in line with said gap formed between said or one of said pair(s) of opposing ends of the belt (which may then just as well be formed as a single piece as it can from circular-arc portions butted together). 
     According to a second embodiment of the invention, said supporting structure is formed of several ring sectors shaped as circular arcs, which are butted together in the circumferential direction,
         either radially in line with the gaps formed between the pairs of opposing ends of said belt, which is also formed of several circular-arc portions butted together,   or radially in line with a gap formed between a pair of opposing ends of the belt and in at least one other location on the circumference of this belt that has no said gap, the belt then being formed as a single piece and providing the device with circumferential continuity.       

     According to one example of how the invention may be embodied that is common to these first and second embodiments, said belt is made of metal. This belt may in this case comprise at least one metal sheet which may or may not be holed and which extends from two of the ends of said or each pair, this metal sheet being substantially cylindrical or shaped as an arc of a cylinder, when the belt is formed as a single piece, or when it is formed as separate portions butted together, respectively. As an alternative, the belt may comprise a plurality of metal cords which are axially juxtaposed and which extend from two of the ends of said or each pair, each of these cords being circular or shaped as an arc of a circle, when the belt is formed as a single piece, or when it is formed of separate portions butted together, respectively. According to yet another variant, the belt may comprise just the one single metal cord making outward and return passes between two of the ends of said or each pair and crimped to these ends for each outward and return portion. 
     According to another example of how the invention may be embodied, this also being common to these first and second embodiments, the belt is essentially made of a textile material. In such a case, it may comprise at least one fabric strip or cord, preferably inextensible, which extends from two of the ends of said or each pair, each textile strip or cord being cylindrical or shaped as an arc of a cylinder, when the belt is formed as a single piece, or when it is formed of separate portions butted together, respectively. 
     In general, it should be noted that the run-flat device according to the invention is preferably based on rubber with which said belt is coated using the aforementioned overmolding. 
     A tubeless mounted assembly according to the invention for a motor vehicle, comprising a wheel rim in several blocks, a tire cover comprising beads mounted respectively against axially internal and external flanges of the rim, and a run-flat device mounted around the rim between these flanges, is as defined hereinabove, with said locking means which are preferably formed as a single piece with the supporting structure and comprise two lateral protrusions which extend axially one on each side of a radially lower zone of said structure and which lock the beads of the cover against the flanges of the rim. 
     One method according to the invention for manufacturing and assembling this mounted assembly comprises, in succession:
         a) overmolding said belt with at least one elastomeric or thermoplastic material so that this material radially and axially surrounds the belt, forming at least one cavity in the radially internal face of the supporting structure which is centered on said or each gap,   the structure thus obtained being split radially in line with said or each cavity thus formed so that this structure then forms:   (i) either a single-piece ring split in a single location on its circumference, in line with the gap formed between said pair of opposing ends of the belt, which is, in this case, formed as a single piece or from circular-arc portions butted together,   (ii) or several circular-arc ring sectors butted together in line with the gaps formed between the opposing ends of each pair of the belt, which is in this case formed by these portions butted together and forming these gaps,   b) mounting the supporting structure thus obtained inside the cover, preferably by hand, by gradually inserting into the cover this structure devoid of the connecting means, either by deforming the two ends of the split ring that it forms in case (i) or by inserting the ring sectors that it forms in case (ii) one after the other and end to end,   c) fitting and fastening the connecting means in the or each cavity formed in step a) so that the ends of said or each facing pair of the belt are joined together and so that the split ring is closed up in case (i) or so that the ring sectors are tightly packed end to end in case (ii), then   d) assembling the blocks of the wheel rim under the radially internal face of this structure.       

     It will be noted that the device according to the invention thus has the advantage that it can be fitted by hand, something which is not generally the case for known run-flat devices with a rubber toric supporting structure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other features, advantages and details of the present invention will become apparent from reading the following description of a number of examples of how the invention may be embodied, which are given by way of nonlimiting illustration, the description being given with reference to the attached drawings, among which: 
         FIG. 1  is an axial half-section view of a mounted assembly incorporating a run-flat device according to the invention, 
         FIG. 2  is a perspective view of a run-flat device according to a first embodiment of the invention showing, in a view radially from the outside, the slit in the annulus formed as a single piece by this device, 
         FIG. 3  is a perspective view of the device of  FIG. 2  from a different angle showing, viewed radially from the inside at the location of this slit, a connecting strap fitted to a pair of ends of a belt forming the reinforcement of the device, 
         FIG. 4  is a perspective view of this belt according to one example of how the invention is embodied, 
         FIG. 5  is a perspective view of another belt according to the invention, corresponding to a variant of  FIG. 4 , 
         FIG. 6  is a perspective view of another belt according to the invention, corresponding to a variant of  FIG. 5 , 
         FIGS. 7 and 8  are perspective views of two belts according to two other variants of the invention, respectively, 
         FIG. 9  is an exploded and perspective view of a detail of  FIG. 3 , showing how a connecting strap is fitted and fixed to the two opposing ends of the belt via fasteners, 
         FIG. 10  is a perspective view of the strap of  FIG. 9 , without these fasteners, 
         FIG. 11  is a perspective view of a connecting strap according to a variant of  FIG. 10 , and likewise without fasteners, 
         FIG. 12  is a perspective view of a run-flat device according to a second embodiment of the invention and showing, viewed radially from the inside between two distinct sectors of this device, one of the two connecting straps fitted to a pair of opposing ends of the reinforcing belt of this device, 
         FIG. 13  is a perspective view of a belt of a run-flat device according to the invention according to a first variant of  FIG. 8 ; 
         FIG. 14  is a perspective view of a belt of a run-flat device according to the invention, according to a second variant of  FIG. 8 ; 
         FIG. 15  is a view of a detail of  FIG. 14 , 
         FIG. 16  is a perspective view of a connecting strap of a belt according to the invention according to a variant of  FIG. 10 , this strap being fitted with fasteners, and 
         FIG. 17  is a perspective view of a run-flat device with a belt that is a one-piece component but has a supporting structure made up of annulus sectors, according to a variant of  FIG. 3 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the present description, the expressions “axially internal” and “axially external” refer respectively to the sides of the wheel rim which are intended to face toward the inside and toward the outside of the motor vehicle when a mounted assembly comprising this rim has been mounted on a vehicle. 
     The mounted assembly  1  according to the invention illustrated in  FIG. 1  comprises:
         a wheel rim  10  with two blocks  10   a  and  10   b  which are joined together by fixing means (not illustrated) of the bolt type and which respectively have axially internal and external flanges  12  and  13  delimiting two rim seats extending axially from the flanges  12  and  13 ,   a tire cover  20  the beads  21  and  22  of which are mounted resting against these seats, and   a run-flat device  30  mounted around a substantially flat bottom of the rim  10  inside the cover  20  and intended to support the latter following a drop in inflation pressure inside the mounted assembly  1  while at the same time locking the beads  21  and  22  against the rim flanges  12  and  13 .       

     The run-flat device  30  according to the example in  FIG. 1  consists of an annular supporting structure, preferably made of rubber, having two lateral protrusions  31  and  32  running axially on each side of a radially interior and maximum width zone of the device  30  and which are designed to lock the beads  21  and  22  against the rim flanges  12  and  13 . The remainder of the device  30  has, radially toward the outside of these locking protrusions  31  and  32 , an axial section of substantially rectangular shape, except in a radially external zone of the structure where it widens in this example into a portion  33  substantially shaped as an isosceles trapezium. It will, however, be noted that the devices according to the invention may have other external shapes, provided that they are able to lock the beads  21  and  22  and to support the cover  20 . 
     The device  30  is reinforced in this radially interior zone by an axial belt  34  to  434  (in the example of  FIG. 1 , more or less radially centered on the protrusions  31  and  32 ) which has an open geometry, in as much as it is defined by at least one pair of opposing ends  34   a  and  34   b  to  434   a  and  434   b  which are separated by an axial connecting gap  34   c  to  434   c  (visible in  FIGS. 4 to 8 ), the or each pair of ends  34   a  and  34   b  to  434   a  and  434   b  being joined together by a removable connecting flange  35 ,  135  (see  FIGS. 10  and  11 ) able to fasten the belt  34  to  434  via fasteners  36  of the screw type, as will be explained hereinbelow with reference to  FIG. 4  et seq. 
     In addition, and as illustrated by its slit  37  visible in  FIGS. 2 and 3 , the device  30  is split right through radially in line with the or each gap  34   c  to  434   c  (i.e. is split from one lateral side of the device  30  to the other and from the radially external face  30   a  to the radially internal face  30   b  thereof), so as to allow the device  30  to be mounted by hand inside the cover  20  by gradually inserting it into this cover without the flanges  35 ,  135 . 
     In the embodiment examples of  FIGS. 4 to 8 , the belt  34  to  434  is formed as a single piece, and therefore has just one pair of ends  34   a  and  34   b  to  434   a  to  434   b  to be connected by the flange  35 ,  135 . However, it will be noted that a belt according to the invention could be formed of at least two circular-arc portions butted together in the circumferential direction and thus defining at least two pairs of such ends which are respectively joined together by at least two flanges  35 ,  135 . 
     In the examples of  FIGS. 4 to 6 , the belt  34  to  234  is made of metal and may therefore in axial section have a flat geometry (as is the case in  FIGS. 4 and 5 ) or a two-dimensional geometry (as is the case in  FIG. 6 ). 
     As illustrated in  FIG. 4 , the belt  34  in this example comprises a solid (i.e. non-holed) cylindrical metal sheet which extends from the two ends  34   a  and  34   b  that are to be connected, which ends each comprise a perforated metal support plate  34   d  which is secured to the remainder of the belt  34 , for example by welding, and through which the screws  36  that fasten the flange  35 ,  135  are intended to pass.  FIG. 4  shows that the two support plates  34   d  both project radially outward with respect to the remainder of the belt  34 , defining the axial gap  34   c  between them. Further, the belt  34  may be equipped with a balancing weight  34   e  diametrically opposite the support plates  34   d  so as to minimize the out-of-balance under running conditions, this weight  34   e  preferably being formed as a projection on the radially internal face of the belt  34 . 
     The belt  134  according to the variant of  FIG. 5  differs from that of  FIG. 4  only in that it has a structure that is holed via slots  134   f  that are evenly spaced in the circumferential direction. As for the belt  234  in  FIG. 6 , it differs from the previous one only by its two lateral flanges which extend radially outward, in the manner of a reel, on each side of the slots  234   f  with which this belt  234  is holed. 
     The belts  334  and  434  according to variants of  FIGS. 7 and 8  are both essentially made of fabric, being provided at each of their two ends  334   a  and  334   b ,  434   a  and  434   d  with a perforated metal support plate  334   d ,  434   b  analogous to that of  FIGS. 4 to 6  and which is connected to the fabric for example by stitching. In this case, it may comprise at least one annular strip of fabric T, T 1 , T 2 , preferably an inextensible fabric (two strips T 1  and T 2  axially juxtaposed such that they are spaced apart in the variant of  FIG. 8 ) which extends from the two ends  334   a  and  334   b ,  434   a  and  434   b.    
     In the embodiment variant illustrated in  FIG. 13 , the belt  534  consists of n(n≧2) annular strips or bands S 1 , S 2 , S 3  which are axially juxtaposed and closed up independently of one another (i.e. without being joined together) by n separate connecting flanges  535 . More specifically, each band S 1  to S 3  has its two ends  534   a  and  534   b  respectively mounted on two support plates  534   d  which are joined together via their internal faces by a connecting flange  535  through all of which fasteners  536  pass. A balancing weight  534   e  has also been provided diametrically opposite the axial gap  534   c  of the belt  534  to minimize the out-of-balance under running conditions, this weight  534   e  in this example being formed as a protrusion on the internal face of only the middle band S 2 . 
     In the variant of  FIGS. 14 and 15 , the individual bands S 1  to S 3  of  FIG. 13  have been replaced with n annular metal cords C 1  to C 3  that are independent (i.e. not joined together) and axially juxtaposed in a spaced-apart manner, which are closed by n separate connecting flanges  635  to form the belt  634  in the axial connecting gap  634   c  thereof. Each flange  635 , which is fitted with fasteners  636 , is mounted under two supports  634   d  that accept the respective wound ends  634   a  and  634   b  of the corresponding cord C 1  to C 3  (which, for example, is made of steel). 
     According to another, unillustrated, variant of the belt according to the invention, this belt may comprise a plurality of metal cords which are axially juxtaposed in a spaced-apart manner but which are joined together by one and the same common connecting flange at the or each axial gap and which run from two of the ends of the or each pair (each cord being shaped as a circle or a circular arc according to whether the belt is formed as a single piece or whether it is formed of separate circular-arc portions butted together), the connection between these cords and the support plates of the or each pair of ends being achieved, for example, by crimping or by cable clamps. 
     With reference to  FIGS. 9 to 11 , the or each connecting flange  35 ,  135  of rectangular shape fitted to the belt  34  to  434  can be fixed removably through the two support plates  34   d ,  334   d ,  434   d  with which the two facing ends  34   a  and  34   b  to  434   a  and  434   b  of the belt are provided and which for this purpose have tapped orifices  36   a  through which the screws  36  that fasten the flange  35 ,  135  to the belt  34  to  434  are intended to pass (the space between these two ends  34   a  and  34   b  to  434   a  and  434   b  corresponds to the width of the flange  35 ,  135  in the circumferential direction when it is fixed under the belt  34  to  434 ). 
     To achieve this fixing, the or each flange  35 ,  135  has through-orifices  36   b  for the screws  36  which, in the example of  FIGS. 9 and 10 , are split into two rows of orifices  36   b  arranged respectively one on each side of a central projection  35   a  running in the axial direction at right angles to the two faces of the flange  35  through which these orifices  36   b  pass. This central projection  35   a  is intended to sit in the gap  34   c  to  434   c  and minimize the bending work of the flange  35  under running conditions. As a variant and as illustrated in  FIG. 11 , the two faces of the or each flange  135  which are provided with orifices  136   b  through which the screws  36  are intended to pass may both be flat. 
       FIG. 12  shows a run-flat device  130  according to the second embodiment of the invention, which differs from the device  30  according to the aforementioned first embodiment in that it is formed of two ring sectors  130 A and  130 B each in the form of a semicircle, which are butted together in the circumferential direction, while being separated from one another by two slits  137   a  and  137   b  at the two gaps (not visible) formed between each pair of opposing ends of the belt, which is likewise formed of two semicircular portions butted together and tightened against one another by two flanges  35 ,  135 . 
     The run-flat device  30 ,  130  according to the invention is advantageously obtained as follows:
         a) the belt  34  to  434  is overmolded, preferably with rubber, so that this rubber radially and axially surrounds this belt, forming, by means of an overmolding insert placed in the mold, at least one blind cavity in the radially internal face  30   b  of the supporting structure which is centered on the or each gap  34   c  to  434   c  (formed between the two ends  34   a  and  34   b  to  434   a  and  434   b  of the or each pair of ends of the belt),
 
the structure thus obtained being radially split in line with the or each cavity, to form:
   (i) a one-piece ring split at a single location  37  on its circumference in line with this gap  34   c  to  434   c , the belt  35 ,  135  in this case being formed as a single piece or of circular-arc portions butted together, or   (ii) several circular-arc ring sectors  130 A and  130 B separated from one another by the slits  137   a  and  137   b , butted together in line with the gaps formed between the pairs of opposing ends of the belt, which in this case is formed by these portions butted together forming these gaps,   b) this device  30 ,  130  thus split and without the or each flange  35 ,  135  is mounted inside the cover  20 , preferably by hand, either by deforming the two ends of the split ring in case (i), or by inserting the ring sectors  130 A and  130 B end to end one after the other, in case (ii),   c) the or each flange  35 ,  135  is fixed and then fastened in the or each cavity formed in step a) so that the ends  34   a  and  34   b  to  434   a  and  434   b  of the or each facing pair of the belt  34  to  434  are joined together, and so that the split ring is closed up in case (i) or so that the ring sectors  130 A and  130 B are clamped end to end in case (ii), then   d) the two blocks  10   a  and  10   b  of the rim  10  are assembled under the radially internal face  30   b  of the device  30 ,  130 .       

     The connecting flange  235  illustrated in the variant of  FIG. 16  essentially differs from that of  FIG. 11  in that it is formed of two parts  235   a  and  235   b  each of which is provided with fasteners  236  and which are articulated to one another by hinges  235   c  arranged in a staggered configuration along the longitudinal mid-plane of the flange  235 . The hinges  235   c  are situated in the axial direction (i.e. in the transverse direction, just like the projection  35   a  of the flange  35  in  FIG. 9 ) of the run-flat device once the latter has been assembled. This articulated flange  235  is notably able to absorb bending stresses to which the corresponding run-flat device is subjected under running conditions, so as to make this device more flexible. 
     The run-flat device  230  according to the variant of  FIG. 17  differs from that of  FIG. 3  in that its belt  634  (in this example made up of cords C 1  to C 3  like that  FIG. 14 , it being emphasized that any other belt structure can be used in this variant) which is split, being formed as a single piece, is here surrounded by a supporting structure  230  in the form of several circular-arc ring sectors  230 A and  230 B (two semicircular sectors in this embodiment example). In the example of  FIG. 17 , the sectors  230 A and  230 B butted together define a first axial slit  237   a  radially in line with the axial gap  634   c  formed between the pair of opposing ends  634   a  and  634   b  of the cords C 1  to C 3  (which are respectively closed up by the flanges  635 ) and a second axial slit  237   b  at a different location (for example diametrically opposite) of the belt  634 . Thus, the latter alone provides the device  230  with circumferential continuity of this slit  237   b , making a further contribution toward the flexibility of this device  230 .