Patent Publication Number: US-2005121125-A1

Title: Inflating and deflating valve for a wheel of a vehicle

Description:
The technical scope of the present invention is that of valves to inflate a vehicle&#39;s tyres and inflation and deflation systems integrating such a valve.  
      Numerous documents describe inflation and deflation valves for tyres. By way of example, we quote patents EP-296017, EP-0246953 and FR-2731655. The latter more particularly describes a remotely controlled inflation and deflation system for a tyre adapted to light vehicles whose tyre pressure is of around 2 bars. However, the slow deflation of the tyre, which may be necessary in certain travel conditions, is not provided for.  
      The aim of the present invention is to supply a valve allowing a slow deflation of the tyre.  
      The invention thus relates to a wheel valve for a vehicle&#39;s tyre of the type incorporating a non-return valve, two half-bodies together delimiting a cavity and assembled with a membrane placed between them to ensure sealing for said half-bodies, the non-return valve being constituted by a tubular element integral with the membrane inside which the closing element is able to move between a seat and a base, said closing element being applied against the seat by the pressure in the tyre, wherein the closing element is subjected to the action of a magnetic field ensuring it is held at the base so as to hold said valve open and ensure the slow deflation of the tyre.  
      According to one characteristic of the invention, the closing element is a steel ball co-operating with the seat delimited by a ring inserted into the tubular element.  
      According to another characteristic of the invention, the magnetic field is produced using a magnetised element placed near to the membrane.  
      According to another characteristic of the invention, the magnetised element is in the form of a ring placed in a scallop in the ring.  
      According to another characteristic of the invention, a grid is placed between the ring and the base of the tubular element so as to limit the ball&#39;s displacement.  
      The invention also relates to a remote control installation for the slow deflation of a wheel tyre including a valve, wherein it comprises a first electrovalve placed in the supply circuit of said valve and three electrovalves placed downstream of the first one.  
      Advantageously, the first electrovalve is three-way.  
      Advantageously, compressed air pressure is applied to the ball using the electrovalve so as to move it away from the seat thus making the tyre communicate with the external atmosphere via the electrovalve.  
      A first advantage of the valve according to the invention lies in the fact that the valve is retained at the magnet so long as the rate of air being evacuated remains low.  
      Another advantage lies in the manufacturing simplicity of the slow deflation system. 
    
    
      Other characteristics, particulars and advantages of the invention will become more apparent from the description given hereafter by way of illustration and in reference to the drawings, in which:  
       FIG. 1  is a diametral section of the valve according to the invention,  
       FIGS. 2 and 3  show two other operating positions of the valve, and  
       FIG. 4  shows one embodiment of the remote control installation. 
    
    
       FIG. 1  shows a section view of a valve  1  constituted by a body  2  composed of two half-bodies  3  and  4 , made of a suitable material, assembled so as to be dismountable or not, face to face, and machined to make them delimit a cavity  5 . Between them and by means of their peripheral edges, the half-bodies  3  and  4  pinch a membrane  6  that is elastically deformable and which divides the cavity into two chambers  7   a  and  7   b . Half-body  3  has a connector  8  opening into chamber  7   a  and intended to be linked to line  9  of the servo-control circuit described more fully in reference to  FIG. 4 . Half-body  4  advantageously has a bore  10  in its central part that opens into chamber  7   b  and is intended to be connected by any suitable means to a supply channel for the vehicle wheel. The membrane  6  is associated with a servo-valve  11  constituted by a tubular element  12  connected to a base  13  whose peripheral crown is integrated into the membrane  6  that delimits a flange  14  or annular seal intended to surround the orifice of the bore  10  so as to insulate it from chamber  7   b . In the Figure, we see that the flange  14  is formed directly by the membrane  6 . The tubular element  12  is subjected to the action of a helicoidal spring  15  pressing on the base  13  and on the inner wall of half-body  3 . The tubular element  12  further integrates a sheath  16  delimiting a seat  17  onto which a ball  18  presses so as to close off chamber  19  delimited by the sheath  16  in communication with the bore  10 . The displacement of the ball  18  is limited by a grid  20  pinched between the base  13  and the sheath  16 .  
      The purpose of the spring  15  is to constantly push the membrane  6  towards half-body  4  and hold the flange  14  against this half-body thereby insulating the bore  10  from chamber  7   b  that communicates with the external atmosphere via exhaust slots  21 .  
      The sheath  16  is provided at the base  13  with a scallop in which a magnetised element  22  is inserted. The ball  18  constituting a closing element for chamber  19  is subjected to the action of a magnetic field when it is at the grid  20  ensuring its holding at the base  13  so as to hold said valve open and ensure the slow deflation of the tyre as will be explained hereafter. The force of the magnet  22  is calculated such as to counteract at least the weight of the ball  18  and the resultant of the aerodynamic forces exerted by the flow of air through chamber  19 .  
      In the configuration shown in  FIG. 1 , the valve  1  is not being acted upon by the inflation and deflation system. The tyre is assumed inflated and the pressure holds the valve  11  closed via the ball  18  being pressed constantly against the seat  17  to insulate chamber  7   a . Furthermore, the spring  15  holds the flange  14  constantly against half-body  4  and thereby closes chamber  7   b.    
      Deflating the tyre in communication with the bore  10  is ensured in two different ways.  FIG. 2  shows the position of the fast deflation valve  1  such as described in the afore-mentioned French patent. To this end, in a known manner, the pressure in chamber  7   a  is lowered so that it acts antagonistically to the spring  15  and brings the membrane  6  back into the position shown. The flange  14  is thus no longer pressing against half-body  4  and communication is established between the bore  10  and the exhaust slots  21  so as to rapidly evacuate outwards the pressurised fluid of the tyre.  
       FIG. 3  shows the position of the slow deflation valve  1  of the tyre. This possibility is important for the driver since a rapid deflation may jeopardise the handling of this vehicle. The starting position is considered the one shown in  FIG. 1  and a brief intake of compressed air is controlled via the connector  8 . This results in the ball  18  being pushed against the grid  20 , which is then held in place thanks to the magnetic field generated by the magnet  22 . The tyre is then made to communicate via the connector  8  through chamber  19  with the channel  9 . Thus, a calibrated outlet of air is evacuated from the tyre without the ball  18  held in place by the magnet  22  being displaced.  
      The valve  1  thus produced may be integrated in a remotely controlled installation for a tyre or tyres as shown in  FIG. 4 . In this Figure, an installation  30  is shown constituted by an assembly  31  for each of the wheels  33  of a vehicle, not shown, and an assembly  32  at the driver&#39;s cab, the vehicle body or any other suitable place. Each wheel  33  is suitably fastened to a hub  34  by means of a wheel rim  35 . The hub  34  is conventionally connected to one of the vehicle&#39;s axles  36 . The valve  1  is suitably fastened to the wheel  37  by means of a revolving joint  41  and is connected to a valve  38  of the tyre  33  thanks to piping  39 . As shown in the Figure, the valve  1  is assembled close to the axis xx′ of the wheel axle  36 . This axle  36  is pierced by piping  40  to make the assembly  32  communicate with the valve  1  by means of a pipe  42 . Assembly  32  is constituted by four electrovalves  43 ,  44 ,  45  and  46 .  
      Electrovalve  43  is a three-way electrovalve that is positioned upstream of the three other electrovalves. It ensures the opening and closing of the piping  42  towards the valve  1 . It also has an open air restoration function using the third way shown. Thus, the electrovalve  4  merely has to be duplicated to a number equal to that of the wheels.  
      Electrovalve  44  is linked to a source of compressed air  47  allowing the wheel  33  to be supplied with compressed air.  
      Electrovalve  45  is linked to a depression source  48  to lower the pressure of the valve  1 .  
      Electrovalve  46  is linked to a choke mechanism  49  for the piping controlled by a coil  50  to control an air flow, which varies according to the number of electrovalves  43 , towards the wheels  33 .  
      The general operation of this system is identical to that of the system described in the afore-mentioned French patent with respect to the inflation and deflation of the wheels. However, the slow deflation function is ensured as follows. A pulsation of compressed air is sent using electrovalve  44 , by opening and closing it rapidly, towards the valve  1 , thereby dislodging the ball  18  from its seat. The ball thereafter takes up the position shown in  FIG. 3 , that is near to the grid  20 . The tyre of the wheel  33  is thus made to communicate with chamber  19 , then with the connector  8 , then with the piping  40 , then with the piping  42  and electrovalve  46 , electrovalve  43  being open and electrovalves  44  and  45  being closed. When deflation has reached the required level, electrovalve  43  is closed and the ball goes back to its starting position shown in  FIG. 1 .  
      Fast deflation is ensured by controlling the opening of electrovalve  45  which, by the low pressure applied in chamber  7   a , compresses the spring  15  and makes the tyre communicate with chamber  7   b  and the exhaust slots  21  with the external atmosphere.  
      The installation according to the invention also allows the easy checking of the inflation pressure by means of a manometer  51  connected to the piping  52  connecting electrovalves  43  and  46 . The ball  18  is dislodged as explained previously and electrovalve  43  is left open and electrovalve  46  left closed. After the pressure has stabilised the measurement is made. After reading, electrovalve  43  is opened to close the valve  1  by causing the displacement of the ball and its application against the seat.