Abstract:
A brake fluid reservoir includes in its upper portion a bottleneck with a thread and a top for receiving a cap with an edge and a top. The top of the bottleneck has channel opens into the atmosphere, one end of the channel leading into the atmosphere, one end of the channel leading into the interior of the bottleneck and the other end communicating with the outside atmosphere via a cavity.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention concerns a brake fluid reservoir with an air vent for pressure balancing, the top of the reservoir body being equipped with a threaded neck accommodating a threaded cap on the neck and having a baffled passageway for venting the reservoir. 
       BACKGROUND INFORMATION 
       [0002]    The realization of brake fluid reservoirs with pressure balancing is known. There exist different embodiments of reservoirs wherein the cap has an element forming a baffle enabling the pressure to be balanced while preventing brake fluid from escaping due to the effect of the vehicle&#39;s sudden acceleration or deceleration, for example, if the brakes are applied suddenly. These solutions are not always satisfactory, however, because the risk of the fluid escaping remains due to the orientation of the baffle, which can be incorrectly oriented with respect to the vehicle axis. 
         [0003]    Document EP 2,189,344 discusses a brake fluid reservoir equipped with a pressure balancing arrangement, thereby avoiding the risk of brake fluid escaping under exceptional conditions through the particular orientation of the outlet of the cap by indexing the seal forming the baffle equipping the interior of the cap. This seal is positioned precisely so that the cap, once screwed into place, is suitably oriented and so that the outlet of the baffle is not turned toward the front, an orientation that would be the most favorable for the escape of brake fluid from the baffle through the effect of sudden braking. 
         [0004]    But this solution, although interesting, has the disadvantage of being complex to realize given that the cap consists of the cap body in the form of a lid with an indexed thread and accommodates the seal forming a baffle, which is itself indexed, by a connecting arrangement that respects the indexing. Finally, a gasket is placed between the cap equipped with its baffle and the top of the neck. The neck must also have an indexed thread so that, when the cap is screwed in place, the baffle will have the correct orientation. 
         [0005]    This solution has the disadvantage of complex manufacture and additional assembly operations resulting in relatively high costs overall. 
       SUMMARY OF THE INVENTION 
       [0006]    An object of the present invention is the realization of a brake fluid reservoir with pressure balancing that is especially simple to produce and use, so as to reduce the cost of the reservoir and ensure the efficiency of the pressure balancing while avoiding the risk of brake fluid escaping. 
         [0007]    To that end, an object of the invention is a brake fluid reservoir of the type described above, characterized in that, 
         [0008]    A) the neck has a top with a pressure balancing channel,
       open on top,   having a first extremity forming an entrance communicating with the interior of the reservoir and a second extremity forming an outlet communicating with the surrounding atmosphere,   occupying at least one portion of the periphery of the top of the neck,   this channel, situated on the interior of the neck, being surrounded on the exterior by a sealing surface,       
 
         [0013]    B) the cap consists of:
       a peripheral edge equipped with internal threading corresponding to the external threading on the neck, and   a flat bottom that engages with the top of the neck when the cap is screwed on,   an annular contact surface between the sealing lip and the edge of the cap, this surface being equipped with an opening straddling the outlet region of the channel to constitute the outlet of the channel when the cap is screwed onto the neck.       
 
         [0017]    The reservoir according to the invention has the advantage of having a one-piece cap incorporating the air vent portion. Likewise, the top of the neck incorporates the channel forming the baffle in such a way that realization of the assembly is especially simple. Use is also simple and the cap can be very easily placed in the appropriate position not only to enable communication between the interior of the brake fluid reservoir and the exterior and balance the pressure to avoid any vacuum in the reservoir even in the event of significant and rapid extraction of brake fluid during braking, but also ensuring that there is no risk that the liquid shaken in the reservoir will escape through the balancing path formed by the channel specifically during a sudden braking action. 
         [0018]    According to an advantageous characteristic, the entrance of the channel is a lateral entrance crossing the partition bordering the channel on the interior. 
         [0019]    This lateral entrance is realized very simply with a mold without requiring any moving parts because this lateral entrance is open on top. 
         [0020]    According to another advantageous characteristic, the channel occupies almost the entire periphery of the upper portion of the neck and is circular in shape, its inlet being separated from its outlet by a partition. 
         [0021]    This circular embodiment of the channel is particularly simple because the channel is circular in shape and the inlet and outlet in the channel are simply separated by a partition, the inlet emerging in the reservoir laterally through removal of a portion of the wall, whereas the outlet communicates from above. 
         [0022]    According to another advantageous characteristic, the pressure balancing channel makes more than one peripheral turn in the upper portion of the neck. 
         [0023]    According to another advantageous characteristic, the flat bottom has a circular sealing lip occupying a position corresponding to the opening of the neck when the cap is screwed onto the neck so that the circular sealing lip inside the neck engages with the partition bordering the channel on the interior. 
         [0024]    This sealing lip completes the seal of the channel over the entire periphery without interfering with the opening of the entrance to the channel, which can pass beneath the lip. This lip ensures the effectiveness of the pressure balancing path consisting of the channel once the cap is screwed onto the neck. 
         [0025]    According to another advantageous characteristic, the outlet is an opening in the shape of a cavity communicating with the threaded region of the cap and that of the neck. 
         [0026]    According to another advantageous characteristic, the upper portion of the neck has, upon its outer surface, an orientation marker for determining the screw position of the cap. 
         [0027]    The present invention will be described in greater detail by an example of a brake fluid reservoir with pressure balancing, shown schematically in the attached drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0028]      FIG. 1  is an isometric view of the top of the reservoir limited to the neck and cap cut by a diametral plane. 
           [0029]      FIG. 2  is an isometric view of the neck of the reservoir. 
           [0030]      FIG. 3  is an isometric view of the neck with the cap cut by a diametral plane and screwed onto the neck. 
           [0031]      FIG. 4  is a bottom view of the cap. 
       
    
    
     DETAILED DESCRIPTION 
       [0032]    According to  FIG. 1 , brake fluid reservoir  1 , shown very partially, has top  11 , equipped with a threaded neck  12 , closed by screw cap  2 , so the reservoir can be filled while ensuring that the pressure is balanced inside the reservoir. The balancing must occur rapidly during operation of the brake system in the event of the rapid removal of brake fluid for this pressure to be at atmospheric pressure, preventing the creation of a pressure drop that would block the extraction of brake fluid by the master cylinder supplied by reservoir  1 . 
         [0033]    Cap  2  has edge  21  with interior threads,  211  corresponding to threads  121  of neck  12  and bottom  22 . On the outside, cap  2  is equipped with portions in relief,  212 , to facilitate gripping it when tightening or loosening. 
         [0034]    According to  FIG. 2 , neck  12  has, beyond exterior threads  121 , upper portion  122  having, on the inside (IG) of the neck, balancing channel  123  that is open on top. This balancing channel,  123 , recessed into upper portion  122 , there occupies a significant portion of the periphery. In this embodiment, channel  123  occupies almost the entire periphery. It is bordered, on the inside (IG) by partition  124  and on the outside of the neck by annular sealing surface  125 . 
         [0035]    As shown in  FIG. 2 , channel  123  has first extremity  123   a  with an inlet consisting of notch  1231  in interior partition  124  and second extremity  123   b,  corresponding to the outlet or outlet region  123   b.  Channel  123 , which almost entirely occupies the periphery of top  122  of neck  12 , separates its inlet  123   a  and its outlet region  123   b  with partition  1232  in such a way that inlet  123   a  of channel  123  and its outlet  123   b  are unable to communicate directly. Communication between inlet  123   a  and outlet  123   b  occurs solely through channel  123  when cap  2  is screwed in place. 
         [0036]    As shown in  FIGS. 1 ,  3 ,  4 , cap  2 , in the shape of a top, has peripheral edge  21 , whose interior surface is provided with threads  212  for screwing to threads  121  of neck  12  and flat bottom  22  ( FIG. 4 ), from which circular sealing lip  221  extends. The geometry of this circular lip  221  is such that whenever cap  2  is screwed to neck  12 , it enters the neck and is applied to interior partition  124  bordering channel  123 . Beyond lip  221 , bottom  22  is flat and forms an annular contact surface  222  intended to surmount upper portion  122  of neck  12 , including channel  123  and partition  124 , in such a way as to create a pressure balancing conduit between inlet  123   a  of channel  123  and its outlet  123   b.    
         [0037]    Annular contact surface  222  is equipped with cavity-shaped opening  2221 , which crosses this surface  222 , for example, in a radial direction so that, when cap  2  is screwed onto neck  12 , opening  2221  straddles channel  123 , thereby constituting the outlet of the channel. 
         [0038]    Cap  2  is screwed in such a way that its opening  2221  encounters outlet region  123   b  of channel  123 . On the exterior, cap  2  has marker  223 , indicating open position  2221 , so it can be positioned by screwing it to the appropriate location. 
         [0039]    Cap  2  can also be indexed by the configuration of its threads  211  and those  121  of neck  12  so that, when it is completely screwed in place, opening  2221  of cap  2  is found in outlet region  123   b  of the channel. 
         [0040]    Cap  2  being screwed on neck  12  forms, with channel  123 , a communication path with a very narrow cross-section, therefore with a significant pressure drop between the channel inlet and its outlet, which enables pressure to be balanced inside reservoir  1  to bring it to atmospheric pressure while preventing brake fluid from escaping from the reservoir through cap  2 . 
         [0041]    Depending on the installation position of reservoir  1  in the engine compartment, cap  2  will be oriented in the most suitable manner to prevent the sudden movement of brake fluid in the reservoir, for example, during sudden braking, from being pushed through the channel to the outlet. The outlet is oriented toward the back, which corresponds to the position toward which there is the least risk of brake fluid being pushed or being pushed violently and being forced through the channel and leaking through the cap. 
         [0042]    According to a variant not shown, channel  123 , which, in the above example, occupies almost the entire periphery of upper portion  122  of the neck, can also be shorter in length and occupy only a fraction of that periphery or have a length that extends over more than one turn in the top of the neck. In this case, cavity shaped opening  2221  straddles only the outlet region of this channel without straddling another portion of the channel in such a way that the communication path between the reservoir inlet and outlet for balancing extends over the entire length of the channel. 
         [0043]    The brake fluid reservoir and its cap are made simply of molded plastic material. The shape of the neck as well as the cap allow for very simple manufacture without requiring a complex mold and moving elements. 
       REFERENCE KEY 
       [0000]    
       
           1  brake fluid reservoir 
           11  top of reservoir 
           12  threaded neck of reservoir 
           121  neck threads 
           122  top of neck 
           123  channel 
           123   a  first extremity of channel 
           123   b  second extremity of channel 
           1231  notch of first extremity  123   a  of the channel 
           1232  partition of second extremity  123   b  of the channel 
           124  interior partition delimiting channel  123   
           125  annular sealing surface 
           2  cap 
           21  edge 
           211  threads 
           212  raised part 
           22  bottom of cap 
           221  sealing lip 
           222  annular contact surface 
           2221  cavity shaped opening 
           223  marker 
         IG interior of neck  12