Abstract:
A filter arrangement for filtering a fluid or gaseous medium, in particular in a motor vehicle, comprising a housing ( 1 ) which holds a filter element ( 3 ) in a receiving space ( 2 ), wherein the filter element ( 3 ) has an edge region ( 4 ) which bears at least in regions against the inner wall ( 5 ) of the housing ( 1 ), is characterized, with regard to the problem of creating a filter arrangement which is of structurally simple design and has a high filter efficiency, in that the housing ( 1 ) is shaped such that the receiving space ( 2 ) tapers at least in regions in at least one spatial direction.

Description:
TECHNICAL FIELD 
       [0001]    The invention relates to a filter arrangement for filtering a fluid or gaseous medium, in particular in a motor vehicle, comprising a housing which holds a filter element in a receiving space, wherein the filter element has an edge region which bears at least in regions against the inner wall of the housing. 
       PRIOR ART 
       [0002]    Filter arrangements of the aforementioned type are used for the filtration of air. For this purpose, the air is sucked into the receiving space by means of an intake and after filtration is discharged by means of an outlet. A filter element is arranged in the receiving space for filtering the incoming air. 
         [0003]    The filter element is provided with a sealing element. The receiving space is sealed against the environment by means of this sealing element. The sealing element is frequently developed as foam, in particular as polyurethane foam. 
         [0004]    The receiving space is usually developed from two parts, that is from the housing and a cover which seals the housing. To seal the housing, sealing measures such as the affixing of foam on the filter element are required, which is costly and time-consuming. 
       DESCRIPTION OF THE INVENTION 
       [0005]    The object of the invention therefore is to create a filter arrangement of the type mentioned at the outset which has a simple structural design and ensures a high filter efficiency. 
         [0006]    The invention teaches that the preceding object is solved by means of a filter arrangement with the features of Claim  1 . According to that, the housing is shaped such that the receiving space tapers at least in regions in at least one spatial direction. 
         [0007]    The invention teaches that this embodiment makes it possible to clamp the filter element and therefore fix it airtight. Furthermore it was also found that the taper enables critical regions within the receiving space to be developed geometrically such that the formation of interstices or gaps between the edge regions of the filter element and the inner wall of the housing is prevented. For this purpose, the filter element with its edge regions at least bears against the inner wall of a housing which preferably has a rectangular and/or cuboid design. Hence a filter arrangement is indicated that has a simple structural design with a high filter efficiency. Consequently, the aforementioned object is solved. 
         [0008]    The housing and the filter element can have different geometric shapes, as long as the housing tapers more than the filter element. 
         [0009]    The receiving space could have corner regions which taper in the direction of the corner regions such that the distance between two opposite surfaces of the inner wall decreases. By means of this specific embodiment, a rectangular filter element is clamped in the critical corner regions such that no interstices or gaps can develop in the corner regions. In view of this background, the cross section of the receiving space could essentially have a rectangular shape and taper in the direction of its corner regions. 
         [0010]    The housing could have at least one groove for holding one part of the filter element. In view of this background, it is actually conceivable, that one pleat of the filter element is inserted into the groove. In this manner, it becomes possible to fix the filter element in the housing on the one hand, and on the other hand achieve a sealing effect between the housing and a cover. 
         [0011]    The housing could have an inlet or discharge flow connection for connecting the flow of the receiving space. Unfiltered or filtered air can be directed through an inlet or discharge connection. Ducts could be attached on said connection by means of hose clamps. 
         [0012]    The housing could be lockable by means of a cover. By providing a cover, the receiving space can be opened for exchanging a spent filter element. 
         [0013]    The cover could have at least one groove for holding a projection of the edge region of the filter element. By means of this specific embodiment, the filter element is fixed on the one hand, and on the other hand a sealing effect between the cover and the housing is accomplished. Any further sealing measures, such as O-rings or other separate components, can be dispensed with. 
         [0014]    The groove could taper such that the projection is compressed when the housing and the cover are assembled. By means of this specific embodiment, the receiving space is particularly sealed reliably against the atmosphere. 
         [0015]    The cover could have an inlet or discharge flow connection for connecting the flow of the receiving space. Unfiltered or filtered air could be directed through the inlet or discharge connection. Ducts could be attached on said connection by means of hose clamps. 
         [0016]    The filter element could comprise a rectangular, pleated layer. In view of this background, it is actually conceivable that the filter element is designed as a flat filter and has rectangular bellows. The pleated design increases the effective filter surface. It is also conceivable that at least the bellows of the filter element has activated carbon particles. By means of this specific embodiment, unpleasant odors can be absorbed. 
         [0017]    The edge regions could be developed strip-shaped and be arranged on the side walls of the layer. By means of this specific embodiment, the development of interstices or gaps between the bellows of the filter element and the inner wall of the housing will be prevented. 
         [0018]    In view of this background, it is conceivable that the layer and/or the edge regions are manufactured from non-woven fabric. Non-woven fabric is particularly suitable for manufacturing filter elements, since its porosity can be adjusted easily. Furthermore, non-woven fabrics can be thermally joined by simple fabrication, without problems. 
         [0019]    The non-woven fabric could be compressed to at least 20% of its thickness in the no-load condition. By means of this specific embodiment, the edge regions could develop an extremely elastic contact element between the inner wall of the housing and the pleated layer. The compressibility to at least 20% of its thickness in the no-load condition permits a particularly tight contact of the filter element in the tapering regions of the housing. 
         [0020]    The edge regions could have a height of 5 to 70 mm and a width of 2 to 4 mm. This specific embodiment permits reliable and leak proof mounting of the edge regions in the groove of the cover. The edge regions project into the groove of the cover such that the edge regions can be compressed from the tapering groove at least at their end. In this manner, a special sealing effect is achieved. 
         [0021]    The folded layer could comprise at least one end pleat that engages with a groove of the housing. By means of this specific embodiment, a sealing effect is achieved on the one hand, and a secure positioning of the filter element in the housing, on the other. 
         [0022]    A filter element could include a flat layer with end pleats and edge regions, wherein the edge regions have projections which protrude beyond the pleat tips of the flat layer. Such filter element is particularly suited for positioning in a filter arrangement described here. The projections of the edge regions, which protrude beyond the pleat tips of the flat layer can on the one hand be advantageously mounted in grooves of a cover of the housing and fix the filter element, and on the other hand accomplish a high seal effect. 
         [0023]    The filter arrangement described here is suited particularly for use in the air intake system of motor vehicles, because it filters the engine intake air especially reliable. The filter arrangement described here is also suitable for the reliable filtration of air in a motor vehicle air conditioning system. 
         [0024]    Thus, there are now different possibilities to design and further develop the teaching of the present invention advantageously. For that purpose, on the one hand, refer to the subordinate claims, and on the other hand, to the subsequent illustration of a preferred embodiment of the invention, by means of the drawing. 
         [0025]    In conjunction with the illustration of the preferred embodiment of the invention, also generally preferred embodiments and developments of the teaching are explained, using the drawing. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0026]    In the drawings, 
           [0027]      FIG. 1  is an isometric view of the housing, 
           [0028]      FIG. 1   a  is a section of a corner region of the housing, 
           [0029]      FIG. 2  is a view of the filter element, 
           [0030]      FIG. 3  is an isometric view of the cover, and 
           [0031]      FIG. 4  is a partial sectional view of the cover. 
       
    
    
     EMBODIMENT OF THE INVENTION 
       [0032]      FIG. 1  shows a housing  1 , which can hold a filter element  3  illustrated in  FIG. 2  in a receiving space  2 . The housing  1  has an inner wall  5 , which the edge regions  4  of the filter element  3  shown in  FIG. 2  bear against. The housing  1  is shaped such, that the receiving space  2  tapers at least in regions in at least one spatial direction, namely in the direction of its corner regions  6 . For this purpose, the receiving space  2  is developed as a rectangular cross section. The receiving space  2  tapers in the direction of the corner regions  6  such that the distance between two opposite surfaces  5   a,    5   b  of the inner wall  5  decreases. For this purpose, the distance between the opposite surfaces  5   a,    5   b  can decrease continuously or discontinuously.  FIG. 1   a  shows a corner region  6  of the housing  1 . 
         [0033]    The housing  1  has at least one groove  7  for holding a part  14 , namely the final pleat of a pleated layer  13  of the filter element  3  according to  FIG. 2 . The housing  1  has an inlet or discharge flow connection  8  for connecting the flow of the receiving space  2 . 
         [0034]    The housing  1  is lockable by means of a cover  9  according to  FIG. 3 . The cover  9  has at least one groove  10  for holding a projection  11  of the edge region  4  of the filter element  3  according to  FIG. 2 . The groove  10  tapers such that the projection  11  is compressed when assembling the housing  1  and the cover  9 .  FIG. 4  shows the taper of the groove  10  as a partial cross section of the cover  9 . The cover  9  has an inlet or discharge flow connection  12  for connecting the flow of the receiving space  2 . 
         [0035]      FIG. 2  shows a rectangular filter element  3 , which is held in receiving space  2 . The filter element  3  has a rectangular pleated layer  13  in the form of bellows. On the side walls of the pleated layer  13 , strip-shaped edge regions  4  of non-woven fabric are arranged. These can either be bonded or welded to the pleated layer  3  [sic]. The layer  13  is also manufactured from non-woven fabric. 
         [0036]    At least the non-woven fabric from which the strip-shaped edge regions  4  are manufactured can be compressed to at least 20% of its thickness in the no-load condition. 
         [0037]    The edge regions  4  are 10 mm high and 3 mm wide. The edge regions  4  have projections  11  which protrude beyond the pleat tips of the flat layer  13 . These projections  11  can be held in the groove  10  of the cover  9 . 
         [0038]    The pleated layer  13  has at least one end pleat  14  which can engage with the groove  7  of the housing  1 . 
         [0039]    As regards further advantageous embodiments and developments of the teaching according to the invention, please refer to the general section of the specification, on the one hand, and on the other to the enclosed patent claims. 
         [0040]    In conclusion, it should be emphasized explicitly that the above embodiment was purely selected at random, merely for discussing the teaching of the invention, and is not limited to this embodiment, however.