Abstract:
A self-sealing device for a tire on a vehicle wheel, including a wheel, a wheel hub supporting the wheel, a wheel supply circuit, an inflating and deflating valve for supplying compressed air from a pressurized circuit, wherein the valve is positioned between the wheel and the wheel hub and includes sealing means integrated into the wheel supply circuit, wherein the sealing means is activatable to an open position in the presence of the valve and to a closed position in the absence of the valve.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of Invention  
         [0002]     The technical scope of the present invention is that of inflation and deflation systems for a vehicle wheel.  
         [0003]     2. Description of the Related Art  
         [0004]     The principle of valves enabling the inflation and deflation of vehicle tires by remote control is known, notably by patents FR-2667826 and FR-2731655.  
         [0005]     In the scope of application above-mentioned, it is known for the valve system to be particularly well adapted to heavy equipment, such as lorries, military vehicles, public works or civil security vehicles. This system has to be adapted when applied to light vehicles.  
         [0006]     The drawback to this system in the case of light vehicles lies firstly in the fact that operations to dismount the wheel and/or the valve always result in the deflation of the tire, thereby making wheel balancing operations both problematic and uncertain. The user or the constructor is thus obliged to install an isolating valve to avoid having to reinflate the wheel.  
         [0007]     Another drawback lies in the fact that the valve and its connection remain accessible from the exterior and are subject to theft and deliberate deterioration (vandalism) or accidental deterioration (shocks to the wheel rim).  
         [0008]     Another drawback lies in the fact that since the system is off-centre with respect to the wheel&#39;s axis of spin it is subjected to high centrifugal forces because of the high spin rate which is prejudicial to its functioning.  
         [0009]     Lastly, fastening the valve to the wheel rim requires drill holes to be made thereby weakening the wheel rim.  
       SUMMARY OF THE INVENTION  
       [0010]     The aim of the present invention is to propose a new manner to integrate a valve in a wheel allowing the inflation pressure in the tire to be maintained during mounting or dismounting of the wheel and/or the valve.  
         [0011]     The invention thus relates to a tire self-sealing device for a vehicle wheel equipped with a tire inflating and deflating valve that ensures a supply of compressed air by means of a pressurised circuit, wherein the valve is positioned between the wheel and the wheel hub and wherein it comprises sealing means integrated into the wheel supply circuit, said means being activated in the open position in the presence of the valve and in the closed position in the absence of the valve.  
         [0012]     The open position designates a state of the sealing element in which air is able to pass from valve to tire or from tire to valve.  
         [0013]     Advantageously, the sealing means are constituted by a finger extended by a truncated cone-shaped part able to move under the action of a spring inside a bore made in the wheel supply circuit, the truncated cone-shaped part able to be applied against a seat having a cone-shaped profile under the action of a spring to close the wheel supply circuit.  
         [0014]     It is obvious that the truncated cone-shape is taken here as an example. Other means, such as a plane or spherical shape may be envisaged, but for the sake of clarity, it is this example which will be used to explain the principle behind the invention.  
         [0015]     Advantageously again, the valve, constituted of a valve body and a bonnet, forms a case delimited by the hub and the seat, both fitted with communication means to enable the provision of compressed air to the wheel from a revolving joint, the seat being placed on the wheel and the valve bonnet on the hub supporting the wheel.  
         [0016]     Advantageously again, the valve is positioned such that is axis of symmetry is the same as the wheel&#39;s axis of spin.  
         [0017]     According to one characteristic, the sealing means are arranged so as to act axially with respect to the wheel.  
         [0018]     Advantageously, the valve is screwed into the hub.  
         [0019]     Advantageously again, the seat is provided with an indexing organ with respect to the hub; the indexing, or locating, organ may, for example, be a pin or screw.  
         [0020]     According to one characteristic, the sealing means are always placed so as to act axially but the valve is fastened to the wheel rim by pressure screws.  
         [0021]     According to another characteristic, the sealing means are positioned to act radially with respect to the wheel.  
         [0022]     Advantageously, the valve seat is extended by a substantially truncated cone-shaped part intended to cooperate with the sealing means, the extension being fitted with communication means between valve and wheel; the wheel is closed to the exterior.  
         [0023]     Advantageously, the valve is held in the seat by friction. By friction we mean a relation enabling the valve to be easily inserted into the bore (for example a pivoting sliding relation) but for which an O-ring ensures the sealing of the assembly.  
         [0024]     Advantageously again, the seat is extended by a substantially cylindrical part capped by a plug with a truncated cone-shaped part intended to cooperate with the sealing means, the plug being screwed onto said extension; the wheel is open to the exterior.  
         [0025]     Another advantage lies in the fact that such an assembly allows the gradual depressurization of the volumes located between the seal and the valve when this is being dismounted.  
         [0026]     A first advantage of the present invention lies in the fact that the tire pressure is maintained even when the wheel or the valve have been dismounted.  
         [0027]     Another advantage lies in the possibility of performing balancing operations without the tricky dismounting of the valve, balancing being carried out by any type of apparatus.  
         [0028]     Another advantage lies in the quick and easy dismounting of the valve after dismounting the wheel.  
         [0029]     Yet another advantage of the invention lies in the fact that the whole system is inaccessible by the exterior, thereby preventing the valve from being deteriorated.  
         [0030]     Yet another advantage lies in the fact that the central position of the valve makes it relatively insensitive to the centrifugal forces, thereby improving its reliability and life time.  
         [0031]     Yet another advantage lies in the technical aspect of easy mounting and minor modification to be made to the wheel or its support.  
         [0032]     Advantageously again, the system is totally sealed so long as the sealing means are not closed. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0033]     Other characteristics, particulars and advantages of the invention will become apparent from the following description of the different embodiments made by way of illustration and in reference to the drawings, in which:  
         [0034]      FIG. 1  is a diametral section of the wheel and all its components according to a first configuration,  
         [0035]      FIG. 2  is an enlarged partial view of  FIG. 1 ,  
         [0036]      FIG. 3  is a partial section showing an embodiment of the sealing means,  
         [0037]      FIG. 4  is a partial section showing another variant embodiment of the invention,  
         [0038]      FIG. 5  is a partial section showing another variant embodiment of the invention, and  
         [0039]      FIG. 6  is a partial section showing another mounting variant for the valve. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0040]      FIG. 1 , which represents a section of a wheel mounted on its drive shaft, shows the wheel  1  constituted of a wheel rim  2  and a tire  3 . The wheel rim  2  is connected to its support shaft  4  by means of a hub  5 . Two bearings  6   a  and  6   b  are classically positioned between the shaft  4  and the hub  5 . These bearings classically comprise an external housing  7  and an internal housing  8  between which is placed a revolving joint  9  to allow pressurised fluid to pass between an external source  10  and the tire  3  as will be explained hereafter in reference to  FIG. 2 . The wheel rim  2  is classically mounted on the hub by means of bolts whose housing  11  can be seen in the Figure. A valve  12  is mounted in the hub  5  and according to the invention comprises a valve bonnet  13  screwed into the hub and a seat  14 , the valve being indexed with respect to the hub by means of a screw  15 . This screw allows the valve  12  to be indexed with respect to the hub to ensure the continuity of the fluid circuit as will be explained after. The Figure also shows a brake disc  16  integral with the hub  5 . The brake disc has grooves  63  allowing air to escape, in accordance with the functioning of the valve explained in the afore-mentioned patents.  
         [0041]     The wheel rim  2  is provided with a radial duct  17  and an axial duct  18  allowing fluid to communicate between the valve  12  and the tire  3  following arrow F. The term radial duct will be used when the duct is arranged if a perpendicular direction to the axis of spin XX′ of the hub  5  and axial direction when the duct is arranged in a parallel direction the axis XX′. According to the invention, sealing means  19  are provided positioned in the axial duct  18 , intended to cooperate with the seat  14  of the valve. The sealing means thus occupy an axial position in this configuration and are in the open position.  
         [0042]      FIG. 2 , which represents an enlarged partial view of  FIG. 1 , shows that the fluid circuit between the source  10  and the tire comprises, in addition to ducts  17  and  18 , a first axial duct  20  extended by a radial duct  21  and a second axial duct  22  made in the seat  14 , an axial bore  23  and a radial duct  24  made in the hub  5 , a slot  25  dividing the internal housing  8  into two parts, a duct  26  made in the external housing  7  and a duct  27  made in the shaft  4 . Naturally, these different ducts are intended to inter-link when these different elements are mounted. The bore  23  is threaded to screw in the valve  12 . Thus, when mounting, the valve bonnet  13  is firstly screwed into the bore  23  in the hub, then the wheel is positioned on the hub and the sealing means installed in the open position pressing on the seat  14 , as shown in the Figure.  
         [0043]     The fluid circuit operates as follows. To supply the tire  3  with pressurised fluid from the source  10 , the passage of air is activated which will successively pass through duct  27 , the revolving joint  9 , the slot  25 , duct  24 , the valve  12 , ducts  22 ,  21  and  20 , the sealing means  19  which are in the open position, duct  18  and lastly duct  17 . If the tire  3  needs to be deflated, the circuit previously described is activated in depression using suitable means.  
         [0044]     The inflating and deflating control means may be those described in patent FR-2731655. They may be used as such without any significant modification. It is thus unnecessary to describe them in detail.  
         [0045]     Naturally, seals are provided to avoid any leakage and to maintain the pressure in the tire at the required value.  
         [0046]      FIG. 3  shows a section of an embodiment of the sealing means  19 . This comprises a pin  30  whose free end presses on the seat  14  and which is extended at its other end by a truncated cone-shaped part  31  on which an elastic element  32 , for example a helicoidal spring, acts. This spring  32  is, for example, applied against the bottom of duct  18 . At the mouth of duct  18 , a retainer  33  has a flared part  34  of the same configuration as part  31 . The retainer  33  is held in place by an insert  35  fixed on the wheel rim  4 . O-rings  36  are integrated in the wheel rim  4  and the seat  14  to ensure sealing between the insert  35 , the wheel rim  4  and the seat  14 . Operation is as follows.  
         [0047]     The seal  19  only lets air through (in one direction or another) when the seat  14  activates the finger  30 , that is to say, when the valve is mounted on the wheel rim, thereby allowing the circulation of air between duct  21  coming from valve  12  and duct  17  communicating with the tire  3 . When the wheel rim is dismounted, the spring  32  pushes the finger  30  towards the exterior of the drill hole  18  so that part  31  comes into close contact with conical surface  34 . In this configuration, the tire  3  is held under pressure by closing the circuit and the balancing operations or interventions on the means can be carried out without loss of pressure. One of the roles of the insert  35  is to ensure the imperviousness of the system between the moment when the finger  30  is activated and the moment when the valve is fixed in an airtight manner to the wheel rim. Similarly, during dismounting, the insert  35  ensures the imperviousness of the system between the start of dismounting and the moment when part  31  ensures the full closure of the seal.  
         [0048]      FIG. 4  shows a variant embodiment in which the sealing means are positioned radially. The finger  30  is placed in the radial duct  17  as is a retainer  40  having a conical surface  17 . The seat  14  is extended by a threaded part  43  able to be screwed onto the wheel rim  2  in a bore  46  closed on the exterior and is provided with a ramp  48  on which the finger  30  presses. This seat  14  is pierced by a radial duct  44  and an axial duct  45  that inter-link. The radial duct  44  communicates with a chamber  54  delimited by the wheel rim  2  and the seat  14 , which in turn communicates with the radial duct  17 . The axial duct  45  communicates with the valve body  13 . This valve is classically isolated in its housing in the hub  5 , for example by means of an O-ring  49 . An O-ring  47  inserted in a housing made in the wheel rim ensures imperviousness between it and the seat  14 . In this configuration, the wheel rim is completely closed with no hold on the valve  12  which is fixed to it by screwing its threaded part  43  in the bore  46 . The assembly is in this case more compact than for the previous case. The valve no longer needs to be indexed. In the Figure, a washer  50 , of the Belleville type, acts as a flange for the valve  12  and keeps it in position. In this embodiment, the valve  12  is not screwed in the hub  5  but is linked by friction in the bore  23 .  
         [0049]     Operation is as follows. When the wheel rim is dismounted, the valve remains fastened to it and merely needs to be unscrewed to be separated from the wheel rim for balancing operations to be carried out. As the valve is being unscrewed, the finger  30  travels along the ramp  48  and comes to press against the cone-shaped surface of the retainer  40  closing the fluid circuit. Similarly, when the valve is being screwed in, the finger  30  travels along the ramp  48  away from the cone-shaped surface of the retainer  40  opening the fluid circuit.  
         [0050]      FIG. 5  shows the assembly of a valve  12  having a configuration identical to that in  FIG. 4  with the exception of the seat  14 . In this embodiment, the wheel rim  2  is open to the exterior, that is to say it has a hole  51  aligned with the bore  23  in the hub. The seat  14  is pierced by a radial duct  52  and an axial duct  53  that are inter-linking. As in the previous case, duct  53  communicates with the valve  12  and duct  52  communicates with a chamber  54  delimited by the wheel rim  2 , the seat  14  and a cap  55 . This cap is screwed onto the end of the bonnet and adjusted in the wheel rim  2  and sealed using an O-ring  56 . This cap incorporates a ramp  57  onto which the seal finger comes into contact. This cap thus seals the chamber  54  with respect to the exterior and also retains the opening of the seal  19 . Another O-ring  58  ensures the sealing between the seat  14  and the wheel rim  2 . The valve  12  is fixed onto the wheel rim by friction and it is the cap  55  which ensures its partial fastening. This fastening is enough to retain the valve and to protect it from stresses during handling operations. Full fastening is obtained using an elastic element  50  of the Belleville washer type. The valve body is also fixed by friction in the hub  5 .  
         [0051]     Assembly is as follows. Firstly, the valve  12  is introduced into the wheel rim  2 , and then the cap  55  is screwed onto the bonnet. As it is being screwed on, by three threads for example, the ramp  57  pushes the finger of the seal  19  which opens the tire supply circuit. The system is ready to function and the wheel may be mounted on the hub. Slightly loosening the cap (a few turns) allows the circuit to be closed whilst holding the valve in position.  
         [0052]     A variant embodiment is shown in  FIG. 6  as an addition to the embodiment shown in  FIG. 1 . In this embodiment, the valve  12  is fastened not on the hub  5  but on the wheel rim  2 . The valve seat  14  is fastened to the wheel rim  2  by means of a tubular insert  60  on the wheel rim. The bonnet is fastened using appropriate linking element, for example three pressure screws in housings  62  adapted to this type of fastening.  
         [0053]     The valve  12  is then housed in the bore in the hub  5 , where it is held by friction. An elastic element, of the Belleville washer type, provides flanging for the valve  12 .  
         [0054]     The invention is not limited to the examples described and shown since various modifications may be made without departing from its scope.