Abstract:
The invention relates to a device (D) for fastening an electronic detection unit ( 100 ) for tyres to a rim (J), this unit being of the type which is fastened to the valve ( 200 ), which valve comprises a part ( 210 ) outside the rim and a part ( 220 ) inside the rim, said device consisting of a connection module ( 300 ) connected on the one hand to the inner part ( 220 ) of the valve ( 200 ) and on the other hand to a preformed receptacle ( 400 ) for accommodating said electronic unit ( 100 ), distinguished in that said receptacle ( 400, 400   a,    400   b ) forms an accommodation volume which is open on the tyre tread side. Applications: detection unit fastened to the vehicle wheels.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to the field of sensors housed in tires and particularly to adaptations used to receive and hold same in position under optimal position. 
       DESCRIPTION OF THE PRIOR ART 
       [0002]    There exist, at the present time, pressure and temperature sensors that are sufficiently compact to be housed in a tire such as those fitted on a motor vehicle. 
         [0003]    The mechanical attachment modes of said sensors are varied and make use of three main techniques which are: 
         [0004]    strapping of a housing containing the electronics of the sensors on the rim, the housing being pressed into the rim base by a belt most frequently made of metal, the tire thus containing said strapping and said electronics, 
         [0005]    attachment of a housing directly on a wall of the rim by boring or gluing of the rim, 
         [0006]    attachment of a housing via the valve hole and the valve itself. 
         [0007]    The majority of solutions using the latter technique are subject to tangential stress occurring during acceleration and deceleration of the vehicles to form a major source of fatigue for the seal involved in fitting. 
         [0008]    A solution to this problem is described in the document FR 2876322 which proposes an assembly of a detection housing inside a tire of the type attached to the body of a valve and comprising the following elements: 
         [0009]    a detection housing receiving the detection components, 
         [0010]    a valve body, 
         [0011]    a seal type tightness means ensuring the tightness between the valve body and the rim, 
         [0012]    a means for holding the valve body in position on the rim, preformed for this purpose with a connection orifice, 
         [0013]    a connection module of the detection housing with the valve body, 
         [0014]    at least one of the elements of said assembly, apart from the tightness means, being preformed so that a part of this element enters the connection orifice so as to rest thereon when the assembly is subjected to tangential stress. 
         [0015]    The applicant observed that this type of assembly involved the drawback of requiring a special valve suitable for the required assembly. Another drawback is that the electronic housing is rendered integral to the valve and can only be replaced or undergo a maintenance operation if the valve itself is disassembled from the rim. 
       DESCRIPTION OF THE INVENTION 
       [0016]    On the basis of this statement, the applicant conducted research intended to attach this type of electronic housing on standard valves. Another aim of this research was to render the electronic housing independent from the valve to facilitate maintenance or replacement operations. 
         [0017]    This research resulted in the design and production of a device for the attachment on a rim of an electronic detection housing for tires of the type attached to the valve which comprises one part outside the rim and one part inside the rim, said device constituted by a connection module connected, on one hand, to the inner part of the valve and, on the other, to a receptacle preformed to receive said electronic housing, characterised in that said receptacle forms a reception volume open on the side of the tire tread which facilitates the access and operation thereof, while preventing the creation of a Faraday cage between the walls of the rim and the receptacle. 
         [0018]    In addition, this feature is particularly advantageous in that it allows the use of a standard valve for the attachment of the housing. In addition, according to the aims of the invention, the housing becomes integral to the receptacle only, is no longer involved in the assembly on the rim and is no longer attached directly to the valve. Therefore, it is no longer necessary to remove the valve to arrange the housing. In this way, only the receptacle and the connection module are liable to be modified according to the applications. The valve used in the attachment device of the invention may thus remain the original valve. 
         [0019]    In order to facilitate the detachability of the housing with respect to the receptacle thereof, said receptacle and the housing are preformed to produce a sliding joint. 
         [0020]    The applicant envisaged several configurations for the device according to the invention. According to a first configuration, the connection module and the receptacle are made of the same part. According to a non-limitative embodiment, said receptacle is then constituted by a sheet of metal preformed essentially with an opening wherein the valve is inserted during assembly, the valve head resting on the edges of said opening. This opening forms said connection module. 
         [0021]    According to second configuration, the connection module is constituted by one or more independent elements of the receptacle. According to a non-limitative embodiment, said connection module is then constituted by a hollow cylinder comprising an inner shoulder and an outer shoulder, the valve being inserted in the cylinder and said valve head resting on the inner shoulder for the purposes of attaching the connection part on the rim, and the receptacle being inserted on the cylinder by means of an orifice provided for this purpose and resting with the edges of said orifice on the outer shoulder. 
         [0022]    According to another embodiment of said second configuration, said connection module is essentially constituted by a nut comprising an inner threaded bore screwed onto the valve for the purposes of attaching the connection module on the rim, said nut being preformed with an outer shoulder, the receptacle being preformed with an orifice wherein the nut is inserted such that the outer shoulder rests on the edges of the orifice. 
         [0023]    According to another particularly advantageous feature, an attachment flange is attached to said receptacle to ensure that the housing is held in position. 
         [0024]    According to another particularly advantageous feature, the housing volume is preformed on the side thereof oriented towards the valve head so as to adopt an offset shape to free, once the housing has been fitted, the volume around the valve head. 
         [0025]    The fundamental concepts of the invention described above in the most basic form thereof, other details and features will emerge more clearly on reading the description hereinafter with reference to the appended figures, giving as a non-limitative example, an embodiment of the device according to the invention. 
     
    
     
       BRIEF DESCRIPTION OF FIGURES 
         [0026]      FIG. 1  is a schematic drawing of an exploded perspective view of an embodiment of the device according to the invention, 
           [0027]      FIG. 2  is a schematic drawing of a perspective view of the device in  FIG. 1  showing the engagement of the housing in the receptacle, 
           [0028]      FIG. 3  is a schematic drawing of a perspective view of the device in  FIG. 1  showing the housing positioned in the receptacle, 
           [0029]      FIG. 4  is a schematic drawing of a perspective bottom view of the device in  FIG. 1 , the housing being positioned in the receptacle, 
           [0030]      FIG. 5  is a schematic drawing of a cross-sectional view of the device in  FIG. 1 , 
           [0031]      FIG. 6  is a schematic drawing of a cross-sectional view of another embodiment of the device according to the invention, 
           [0032]      FIG. 7  is a schematic drawing of an exploded perspective view of another embodiment of the device according to the invention, 
           [0033]      FIG. 8  is a schematic drawing of a cross-sectional view of another embodiment of the device according to the invention. 
       
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0034]    As illustrated in the drawing in  FIGS. 1 and 5 , the device referenced D overall performs the attachment on the rim J (partially represented herein by a washer) of an electronic detection housing  100  for tires of the type being attached to the valve  200  which comprises, once fitted, a part  210  outside the rim and a part  220  inside the rim comprising a head  221 . 
         [0035]    According to the invention, the device D is constituted by a connection module  300  connected, on one hand, to the inner part  220  of the valve  200  and, on the other, to a receptacle  400  preformed to receive said electronic housing  100 . In this way, the housing is not directly connected to the valve which allows the interchangeability of said housing without removing the valve. 
         [0036]    According to the embodiment illustrated, the device also comprises a seal  500  associated with a hollow washer  600  which rests J around the valve hole J 1 . 
         [0037]    As illustrated, said receptacle  400  and the housing  100  are preformed to produce a sliding joint. 
         [0038]    According to the invention and according to the embodiment illustrated, said receptacle  400  is constituted by a sheet of metal  410  preformed essentially with an opening  411  wherein the valve  200  is inserted and on the edges  412  whereof the valve head  221  rests, said opening forming said connection part  300 . According to the embodiment illustrated, the opening  411  is an orifice produced in the thickness of the sheet of metal  410  and located such that the edge  412  surrounds same completely. 
         [0039]    According to the embodiment illustrated, said sheet of metal  410  is provided with a plurality of openings so as to lighten the structure formed, which offers the advantage of reducing stress on the valve  200 . 
         [0040]    According to a particularly advantageous feature, the thickness of the sheet of metal is sufficiently small so that the threading conventionally used for the assembly of the standard valve  200  can be used. In this way, the device according to the invention does not require any modification of the assembly existing on a standard valve. Indeed, as illustrated in the drawing in  FIGS. 1 and 5 , the elements of the assembly of a standard valve  200  are constituted by the valve  200  and the nut  700 , the device D merely adds a thickness between the inner surface of the rim J and the bearing surface of the valve head  221 . This additional thickness is constituted by the height of the washer  600  and the thickness of the sheet of metal. 
         [0041]    In spite of the reduced thickness and the different openings made in the metal sheet, the material of the receptacle formed in this way is selected to form a rigid and non-deformable frame to receive the electronic housing. 
         [0042]    As illustrated, the volume of housing  100  is preformed on the side oriented towards the valve head  221  so as to adopt an offset shape  110  to prevent the formation of an obstacle at the air inlet or outlet from the head  221  of the valve  200 . In order to render the housing  100  completely independent from the valve  200 , said receptacle  400  forms a bearing platform  420  for the housing  100 , the surface of said platform and the bearing surface for the valve head  221  proposed by the connection part  300  and the respective distance thereof are defined such that the valve head  221  does not come into contact with said housing  100 . 
         [0043]    According to the embodiment illustrated, the sheet of metal forming the receptacle  100  comprises a plane central part forming the platform  420  on two opposite sides whereof two substantially plane lateral parts  430  and  440  rise to form the sides of the receptacle  400 . As illustrated, the ends  431  and  441  of said sides  430  and  440  not connected to the platform  420  are preformed with an internal return to form longitudinal offset volumes with which projecting volumes  120  and  130  of the outer surface of the housing cooperate to form said sliding joint. 
         [0044]    As illustrated by the drawings in the figures, to ensure the housing  100  is held in position in the receptacle  400 , the housing and the receptacle are each preformed with an orifice  140  and  450  corresponding once the housing is positioned in the receptacle and whereby an attachment pin  800  is positioned. This pin is fastened inside the orifice  140  produced in the housing  100 . 
         [0045]    According to another embodiment not illustrated, another solution to lock said sliding joint in translation comprises preforming said receptacle  100  on the upper face thereof with an offset shape with which a projecting pin preformed on the lower face of the housing cooperates. 
         [0046]    According to the non-limitative embodiment illustrated by the drawing in  FIG. 6 , said connection part  300   a  is an independent part of the receptacle and is constituted by a hollow cylinder comprising an inner shoulder  310   a  and an outer shoulder  320   a,  the valve  200  being inserted in the cylinder  300   a  and said valve head  221  resting on the inner shoulder  310   a  for the purposes of attaching the connection part on the rim J, and the receptacle  400   a  being engaged on the cylinder  300   a  by means of an orifice  410   a  provided for this purpose and resting with the edges  411   a  of said orifice  410   a  on the outer shoulder  320   a.  The cylinder  300   a  may then slide in the receptacle  400   a.    
         [0047]    As illustrated, a compression spring  900  positioned around the connection part  300   a  comprises one end  910  resting on the rim J and one end  920  resting on the receptacle  400   a  so as to hold the receptacle  400   a  in position against the outer shoulder  411   a.    
         [0048]    The embodiment illustrated by the drawing in  FIG. 8  also shows a solution wherein the connection module forms an intermediate part essentially constituted by a nut  700   c  comprising an inner threaded bore screwed onto the valve  200   c  for the purposes of attaching the connection module on the rim J, said nut being preformed with an outer shoulder  710   c,  the receptacle  400   c  being preformed with an orifice  410   c  wherein the nut  700   c  is inserted such that the outer shoulder  710   c  rests on the edges of the orifice  410   c.  A spring  900  holds, resting on the rim, the edge of the orifice  410   c  provided in the receptacle  400   c  against the outer shoulder of the nut  700   c.    
         [0049]    The embodiment illustrated by the drawing in  FIG. 7  represents an alternative embodiment having features of the first and the second embodiments. In this embodiment, the connection part  300   b  is integral to the receptacle  400   b  and is constituted by a hollow cylinder comprising an inner shoulder not illustrated, the valve  200  being inserted in the cylinder  300   b  and said valve head  221  resting on the inner shoulder for the purposes of attaching the connection part  300   b  on the rim J. 
         [0050]    In this embodiment and according to a feature of the invention, an attachment flange  460   b  is attached to said receptacle  400   b  to ensure that the housing  100   b  is held in position in the receptacle  400   b.  The flange  460   b  is fastened on the sides of the receptacle  400   b.    
         [0051]    According to all the embodiments, said receptacle  400  forms an open receiving volume on the side of the tire tread. 
         [0052]    It is understood that the device described and represented above has been described and represented with a view to a disclosure rather than a limitation. Naturally, various arrangements, modifications and improvements may be added to the example above, without leaving the scope of the invention.