Patent Document

BACKGROUND OF THE INVENTION 
     The invention relates to the field of motor vehicles and more specifically to a brake fluid reservoir supplying the hydraulic brake and clutch circuits. 
     In a general manner, a hydraulic brake circuit comprises a brake fluid reservoir containing a hydraulic fluid, this fluid being intended to transmit a hydraulic pressure to the brakes of the front and rear wheels that is formed by the movement of a piston in a master cylinder when the driver of the vehicle actuates a braking means, for example the brake pedal. 
     There are other hydraulic systems in motor vehicles, particularly the clutch, which can use the same hydraulic fluid as the hydraulic brake circuit. In order to simplify the hydraulic circuits, a common hydraulic fluid reservoir is used for both circuits, namely for the brake circuit and for the clutch circuit. These reservoirs are typically made of plastic in the form of two shells assembled by welding. 
     Since the hydraulic absorption of the brake circuit increases with wear on the friction elements, there is a progressive loss of brake fluid, which means that brake fluid should be periodically added to the reservoir so as to keep a substantially constant fluid level in the brake fluid reservoir. By contrast, wear on the clutch usually results in hydraulic fluid being driven back into the reservoir. There is thus a transfer of hydraulic fluid from the reservoir toward the brake. If a common hydraulic fluid reservoir is used for the brake circuits and the clutch circuits, there may occur a progressive transfer of hydraulic fluid from the clutch toward the brake. This liquid may be loaded with solid, metal or non-metal, particles or debris which detach, by abrasion or any other mechanism, from the metal walls with which the fluid is in contact. The largest dimension of these particles or debris is typically between 100 and 500 μm. 
     They can be entrained into the brake circuit, where their presence is particularly undesirable. Specifically, anti-lock braking systems (ABS) typically include electronically operated valves which are generally solenoid ball valves; these solenoid valves can become impaired when solid particles or debris passes through them. Similarly, an ABS-type system includes seals which are liable to become impaired if they come into contact with solid particles or debris. 
     SUMMARY OF THE INVENTION 
     The problem that the present invention is intended to solve is that of positioning, at a suitable point in the hydraulic brake or clutch circuit, a filtration means which makes it possible to confine the solid particles or debris entrained by the hydraulic fluid without any risk of this filtration means clogging up during use. 
     The invention relates to a device for supplying a hydraulic brake circuit which, by means of filtration, prevents brake circuits from being contaminated with particles originating from the hydraulic clutch circuit. 
     The device for supplying a hydraulic brake fluid, termed a downstream hydraulic fluid, to a hydraulic brake circuit of a motor vehicle equipped with a hydraulically controlled clutch comprises an enclosure intended to contain said hydraulic fluid, said enclosure being provided with at least one outlet nozzle supplying said hydraulic circuit, and with an inlet orifice allowing said downstream hydraulic fluid to be introduced into said enclosure so as to compensate for any loss or consumption of said downstream hydraulic fluid in said hydraulic brake circuit. 
     It is characterized in that:
     a) said enclosure is an enclosure, termed a downstream enclosure, forming a portion, termed a downstream portion, of a reservoir, said reservoir comprising a portion, termed an upstream portion, forming an enclosure, termed an upstream enclosure, intended to be supplied with a hydraulic fluid, termed an upstream hydraulic fluid, from the clutch of said vehicle,   b) said upstream enclosure comprises at least one nozzle, termed an inlet nozzle, said inlet nozzle serving to transfer said upstream hydraulic fluid from said clutch toward said upstream enclosure,   c) said inlet orifice is an intermediate orifice whereby said upstream enclosure opens into said downstream enclosure, said intermediate orifice being equipped with a means for filtering said upstream hydraulic fluid so as to continuously convert said upstream hydraulic fluid, typically loaded with solid particles, into said downstream hydraulic fluid devoid of solid particles and thus fit for supplying said brake circuit.   

     The combination a) to c) of the means characteristic of the invention makes it possible to solve the problems addressed. Specifically, by purifying and transferring the upstream hydraulic fluid from the clutch chamber, it makes it possible to provide the additional brake fluid necessary to compensate for the losses of brake fluid or hydraulic fluid in the brake circuit without requiring an external input of brake fluid. 
     The device according to the invention additionally has the advantage of being compact, which means that it can be easily installed in a motor vehicle. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       All the figures relate to the invention. 
         FIG. 1   a  is a section through part of the device  1  on a vertical plane comprising an axial direction  11 . 
         FIG. 1   b  is a perspective view from above of said part of  FIG. 1   a  prior to assembling the filtration means  5 . 
         FIGS. 2   a  and  2   b  are perspective views relating to a filtration means  5  comprising a part termed a long annular part  50   b.    
         FIG. 2   a  is a side view from below. 
         FIG. 2   b  is a side view from above. 
         FIGS. 3   a  and  3   b  are perspective views relating to a filtration means  5  comprising a part termed a short annular part  50   a.    
         FIG. 3   a  is a side view from above. 
         FIG. 3   b  is a side view from below. 
         FIG. 3   c  is a section through said part of  FIG. 1   a , on the horizontal plane A-A of  FIG. 1   a , said horizontal plane being perpendicular to said axial direction  11 . 
         FIGS. 4   a  and  4   b  are perspective views of the device  1  comprising a reservoir  3  equipped with a lower shell  34  and with an upper shell  35  which forms a lid for the lower shell  34 . 
         FIG. 4   a  is a side view from above. 
         FIG. 4   b  is a side view from below. 
         FIG. 5   a  is a schematic and functional representation of the device  1  in section on a vertical plane comprising said axial direction  11 . 
         FIG. 5   b  is a view from above of the lower shell  34  in which the detection means  6  has been represented. 
     
    
    
     DETAILED DESCRIPTION 
     As can be observed from  FIG. 5   a , said reservoir  3  can comprise an outer wall  32 , said outer wall  32  being traversed by said outlet  20  and inlet  40  nozzles and comprising a bottom portion  320  forming a base, a lateral portion  321  forming a side wall and an upper portion  322  forming a crown, and an inner wall  33  forming, together with said filtration means  5 , a partition of said reservoir  3  which isolates said upstream  4  and downstream  2 ′ enclosures. Other vertical or substantially vertical bulkheads (not shown) extend from its base and over some of the height of the reservoir. 
     As can be seen from  FIGS. 5   a  and  5   b , said upstream enclosure  4  can form a container body  4 ′ equipped with a wall, termed an upstream wall  41 , comprising an opening  42 , typically an upper opening  42 ′, cooperating with said filtration means  5 , one portion of said upstream wall  41  forming said inner wall  33 , the other portion of said upstream wall  41  forming a wall, termed a common wall  10 , with said outer wall  32 , said common wall  10  being traversed by said inlet nozzle  40 , typically perpendicular to said common wall  10 . Said common wall  10  can comprise a first common wall  10   a  forming part of said lateral portion  321  of said reservoir  3 . 
     Furthermore, said common wall  10  can comprise a second common wall  10   b  forming part of said bottom portion  320  of said reservoir  3 . 
     According to another configuration, which has not been illustrated by a figure, said common wall  10  can optionally comprise a third common wall forming part of said upper portion  322  of said reservoir  3 . 
     As illustrated in  FIGS. 4   a  and  4   b , said reservoir  3  can be a reservoir  3 ′ made of plastic comprising a shell, termed a lower shell  34 , and a shell, termed an upper shell  35 , said lower  34  and upper  35  shells being molded parts  34 ′,  35 ′ assembled by their assembly flanges, said lower shell  34  having a flange, termed an upper assembly flange  340 , cooperating with a flange, termed a lower assembly flange  350 , of said upper shell  35  in an assembly plane  36  so as to form said reservoir  3 . 
     As illustrated in  FIGS. 1   a  and  1   b , said container body  4 ′ forming said upstream enclosure  4  can be an axial container body  4 ″ having an axial direction  43 , said body  4 ″ comprising a base  410 , a lateral skirt  411  having a typically circular cross section in a plane perpendicular to said axial direction  43 , and said opening  42  typically having said cross section. 
     According to the invention and as illustrated in  FIGS. 2   a  to  3   b , said filtration means  5  can form a composite filtration element  5 ′ comprising a peripheral portion  50  assembled in a sealed manner to said container body  4 ′,  4 ″, and a filtering central portion  51 . 
     Said filtering central portion  51  can form a filter cloth  51 ′ and said peripheral portion  50  can form an annular part  50 ′ made of plastic overmolding the whole of a peripheral edge  510  of said filter cloth  51 ′ so as to secure said filter cloth  51 ′ to said annular part  50 ′, and such that all of said upstream fluid flowing from said upstream enclosure  4  toward said downstream enclosure  2 ′ passes through said filter cloth  51 ′ in order to rid said upstream fluid of said solid particles. 
     According to one configuration illustrated in  FIGS. 3   a  and  3   b , said annular part  50 ′ can be a part termed a short annular part  50   a , said short annular part  50   a  essentially comprising an annular sealing lip  500 . 
     In one advantageous embodiment, said filter cloth  51 ′ has a mesh size of between 50 and 250 μm, preferably between 100 and 150 μm. By way of example, a mesh size of 120 μm is very suitable. Said central filtering portion  51  can be formed of polyamide (PA) or polypropylene (PP). 
     According to another configuration illustrated in  FIGS. 2   a  and  2   b , said annular part  50 ′ can be a part termed a long annular part  50   b , said long annular part  50   b  comprising said sealing lip  500  and an axial projection  501  designed to slide inside said container body  4 ′,  4 ″, said axial projection  501  advantageously comprising a cut-out portion  502  facing said inlet nozzle  40 . 
     In one particular embodiment, said sealing lip  500  can cooperate in a sealed manner with a flange  412  of said container body  4 ′,  4 ″, advantageously by means of an annular weld. 
     As can be seen from  FIGS. 1   b ,  3   c  and  5   b , said container body  4 ′,  4 ″ can comprise at least one inner radial projection  44  providing a predetermined axial positioning for said filtration means  5  with respect to said container body  4 ′,  4 ″. 
     As illustrated in  FIGS. 4   a  to  5   a , said device  1  can comprise a means  6  for detecting the level of said downstream hydraulic fluid in said downstream enclosure  2 ′. 
     It can be seen from these same figures that said reservoir  3  can comprise an upper opening  37  closed by a removable cap  38  so as to allow a filling, for example an initial filling, of said downstream enclosure  2 ′ with hydraulic brake fluid. 
     As illustrated in  FIG. 5   a , said assembly plane  36  can be a horizontal plane  36 ′, said horizontal assembly plane  36 ′, being intended to be located preferably above the level of said downstream hydraulic fluid in said downstream enclosure  2 ′. 
     According to the invention, said filtration means  5  can have a filtering area ranging from 0.15 cm 2  to 100 cm 2 , preferably from 2 cm 2  to 20 cm 2 , and preferably still from 3 cm 2  to 10 cm 2 . This large filtering area has an advantage over an installation of the filtration means in a hydraulic line, since hydraulic lines generally have quite a small diameter of around 4 or 5 mm. Owing to the large filtering area, the filtration means is not at risk of being obstructed by the particles and debris which it retains. 
     Moreover, given the installation of the filtration means  5  in the supply reservoir  3  and given its geometric arrangement, most of the retained particles and debris drop to the bottom of the upstream portion  31  of said reservoir  3 , where they are not at risk of being entrained into the outlet nozzles  20 . However, it would not constitute a departure from the scope of the present invention to design the filtration means to extend vertically and/or obliquely. According to the findings observed by the Applicant, the device according to the invention makes it possible to use the same filter cloth throughout the life of the device in the knowledge that, given the method, namely welding, used to assembly the two shells which form said device, it is virtually impossible to replace said filter cloth. 
     Typically, said downstream enclosure  2 ′ and said upstream enclosure  4  can have storage capacities respectively designated C V  and C M  such that the ratio C V /C M  ranges from 3 to 30. 
     EXAMPLES 
     The figures correspond to exemplary embodiments of devices  1  or parts of devices  1  according to the invention. 
     Two configurations of the device  1 , which is represented particularly in  FIGS. 4   a  and  4   b , were manufactured:
     a) according to a first configuration, the filtration means  5  comprises an annular part with a short skirt  50   a  as represented in  FIGS. 3   a  and  3   b,      b) according to a second configuration, the filtration means  5  comprises an annular part with a long skirt  50   b  as represented in  FIGS. 2   a  and  2   b.      

     For that purpose: upper shells  35 ,  35 ′ were manufactured or made available by molding a plastic, for example a polypropylene; a first configuration  34   a  of lower shell  34 ,  34 ′ tailored to said annular part  50   a  with a short skirt was manufactured, as illustrated in  FIGS. 5   a  and  5   b ; a second configuration  34   b  of lower shell  34 ,  34 ′ tailored to said annular part  50   b  with a long skirt was manufactured, as illustrated in  FIGS. 1   a  and  1   b , the lower shells  34 ,  34 ′,  34   a ,  34   b  being formed by molding a thermoplastic, for example a polypropylene. In this case, as can be seen from  FIGS. 1   a ,  1   b  and  3   c , said upstream enclosure  4 ,  4 ′,  4 ″ comprises a plurality of radial projections  44  and  44 ′ intended to cooperate with the axial projection  501  of the long annular part  50   b ; the detection means  6  was formed or made available and it was assembled to said upper shell  35 ,  35 ′; two configurations of said filtration means  5 ,  5 ′ were formed or made available, a first configuration  50   a  according to  FIGS. 3   a  and  3   b  and a second configuration  50   b  according to  FIGS. 2   a  and  2   b . Filtration means  50   a ,  50   b  were manufactured for example by overmolding the edge  510  of a circular portion of filter cloth  51 ′ into said annular plastic part  50 ′ forming said peripheral portion  50 ; the filtration means  50   a ,  50   b  was assembled in a sealed manner to the corresponding lower shell  34   a ,  34   b , for example by welding the annular sealing lip  500  to the opening  42  of said upstream enclosure  4  and, for example, to the flange  412  of the lateral skirt  411  forming said upstream wall  41 ; finally, the edges  340 ,  350  of the shells  34 ,  35  were welded to one another so as to form said plastic reservoirs  3 ,  3 ′. 
     Upper shells  35 ,  35 ′ and lower shells  34 ,  34 ′,  34   a ,  34   b  made of polyamide were also manufactured. 
     Advantageously, filter cloths  51  consisting of PP were used in the case of shells made of PP and cloths made of PA were used in the case of shells made of PA, so as to make it easier to weld the filter cloth  51  to the lower shell  34 ,  34 ′,  34   a ,  34   b.    
     LIST OF REFERENCES 
     
       
         
               
               
               
             
           
               
                   
                   
               
             
             
               
                   
                 Supply device 
                  1 
               
               
                   
                 Wall common to 32 and to 4/4′ 
                  10 
               
               
                   
                 First common wall 
                  10a 
               
               
                   
                 Second common wall 
                  10b 
               
               
                   
                 Axial direction 
                  11 
               
               
                   
                 Enclosure for hydraulic brake fluid 
                  2 
               
               
                   
                 Downstream enclosure 
                  2′ 
               
               
                   
                 Outlet nozzle 
                  20 
               
               
                   
                 Inlet orifice 
                  21 
               
               
                   
                 Intermediate orifice 
                  21′ 
               
               
                   
                 Partial bulkhead 
                  22 
               
               
                   
                 Reservoir 
                  3 
               
               
                   
                 Reservoir made of plastic 
                  3′ 
               
               
                   
                 Downstream portion of 3 forming 2′ 
                  30 
               
               
                   
                 Upstream portion forming 4 
                  31 
               
               
                   
                 Outer wall 
                  32 
               
               
                   
                 Bottom portion or base 
                 320 
               
               
                   
                 Lateral portion, side wall 
                 321 
               
               
                   
                 Upper portion, crown 
                 322 
               
               
                   
                 Inner wall 
                  33 
               
               
                   
                 Lower shell 
                  34, 34′, 34a, 34b, 
               
               
                   
                 Upper flange 
                 340 
               
               
                   
                 Upper shell 
                  35, 35′ 
               
               
                   
                 Lower flange 
                  35 
               
               
                   
                 Assembly plane 
                  36 
               
               
                   
                 Horizontal assembly plane 
                  36′ 
               
               
                   
                 Opening 
                  37 
               
               
                   
                 Upper opening 
                  37′ 
               
               
                   
                 Removable cap 
                  38 
               
               
                   
                 Upstream enclosure 
                  4 
               
               
                   
                 Container body 
                  4′ 
               
               
                   
                 Axial container body 
                  4″ 
               
               
                   
                 Inlet nozzle 
                  40 
               
               
                   
                 Upstream wall 
                  41 
               
               
                   
                 Base 
                 410 
               
               
                   
                 Lateral skirt 
                 411 
               
               
                   
                 Flange of 411 
                 412 
               
               
                   
                 Opening of 4, 4′ 
                  42 
               
               
                   
                 Axial direction of 4″ 
                  43 
               
               
                   
                 Inner radial projection 
                  44, 44′ 
               
               
                   
                 Filtration means 
                  5 
               
               
                   
                 Composite part 
                  5′ 
               
               
                   
                 Peripheral portion 
                  50 
               
               
                   
                 Annular part made of plastic 
                  50′ 
               
               
                   
                 Annular part with a short skirt 
                  50a 
               
               
                   
                 Annular part with a long skirt 
                  50b 
               
               
                   
                 Annular sealing lip 
                 500 
               
               
                   
                 Axial projection 
                 501 
               
               
                   
                 Cut-out portion facing 40 
                 502 
               
               
                   
                 Filtering central portion 
                  51 
               
               
                   
                 Filter cloth 
                  51′ 
               
               
                   
                 Overmolded edge of 51, 51′ 
                 510 
               
               
                   
                 Level detection means 
                  6

Technology Category: 4