Abstract:
An air filter device is provided with a filter housing and a filter element arranged in the filter housing. A frame part is connected to the filter element and frames the filter element at least over sections thereof circumferentially. The frame part is provided with an air duct receptacle that is adapted to receive an air duct. The frame part is arranged at least partially on an exterior side of the filter housing. The filter element is fastened by the frame part on the filter housing.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of German patent application No. 10 2013 015 497.9 filed Sep. 19, 2013, the entire contents of the aforesaid German patent application being incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    The invention concerns an air filter device, especially for a motor vehicle, especially for a truck, comprising a filter element that is received in a filter housing and, at least over sections thereof, is framed by a circumferentially extending frame part. 
         [0003]    DE 10 2011 011 595 A1 discloses an air filter device for a motor vehicle which comprises, in a filter housing, a filter element that is connected at its inflow end face with a frame part which laterally projects past the circumferential surface of the filter element and serves for supporting it on the end face rim of the filter housing. In the inserted state, the frame part is resting on the rim of the filter housing and is forced by an attached cover, to be connected by securing clips with the filter housing, against the filter housing. The air supply is realized through the cover which is designed as a cyclone separator with a bottom part and a top part. 
       SUMMARY OF THE INVENTION 
       [0004]    It is the object of the invention to configure an air filter device in a constructively simple manner. 
         [0005]    This object is solved according to the invention in that the circumferentially extending frame part on the filter element forms an air duct receptacle for an air duct, wherein the frame part is arranged at least partially on the exterior side of the filter housing. 
         [0006]    The dependent claims provide expedient further developments. 
         [0007]    The air filter device according to the invention can be used in motor vehicles in order to subject the combustion air to be supplied to the internal combustion engine to filtration. Conceivable is a use in trucks as well as in passenger cars. 
         [0008]    The air filter device has a filter housing and a filter element received therein that is partially or completely framed by a circumferentially extending frame part that forms a carrying frame. The frame part is located preferably at an end face of the filter element, in particular at the inflow end face. 
         [0009]    The frame part can be used for securing and holding the filter element. Moreover, the frame part has the function of providing an air duct receptacle for an air duct which is part of the air flow passage through the air filter device. The frame part thus receives the air duct and connects the air duct with the filter element. The air duct serves preferably for supply of raw air to the raw or inflow side of the filter element; possible is however also an arrangement of the air duct at the clean or outflow side of the filter element and, accordingly, a configuration as clean air duct. 
         [0010]    The frame part in the mounted state is arranged at least partially on the exterior side of the filter housing. In this way, it is possible to directly connect the air duct with the frame part; also, the externally positioned projecting section of the frame part can be used for connection with the filter housing. The frame part thus has a dual function: on the one hand, the connection of the filter element with the filter housing and, on the other hand, the connection of the air duct with the filter element. An additional attachment device for attachment of the air duct on the filter housing is not required. 
         [0011]    The frame part is fastened, for example, by means of securing clips on the filter housing. The securing clip is located preferably on the exterior wall of the filter housing and can be brought into a form-fit securing position on the frame part. 
         [0012]    The air duct is preferably inserted into the frame part so that the frame part surrounds the end face of the inserted air duct. Fastening and securing of the frame part on the filter housing is realized by means of the exterior side of the frame part, for example, by means of the aforementioned securing clips. The air duct can be optionally form-fittingly connected with the frame part, for example, by means of elastic springy locking noses on the exterior side of the air duct which, in the mounted state, project into recesses provided in the frame part. For detaching the air duct, the elastic locking noses can be pushed out of the recesses. By attachment of the frame part on the filter housing, the raw air duct is thus secured indirectly on the filter housing at the same time. 
         [0013]    According to a further advantageous embodiment, the frame part is secured fluid-tightly on the filter housing in order to avoid leak flows. For this purpose, a sealing element is provided that is designed advantageously so as to extend circumferentially and is positioned in a circumferentially extending open receptacle in the frame part. In the mounted state, the sealing element is resting on the filter housing wall. 
         [0014]    The sealing element can have correlated therewith a support bead provided at the filter housing; the support bead projects past the immediately neighboring sections of the filter housing wall and the sealing element is supported on the support bead. The support bead has advantageously a width that is reduced in comparison to the sealing element provided at the frame part so that, in the mounted state, the support bead is positioned with lateral spacing relative to the frame part walls. This reduces the risk of shearing off of the sealing element in case of a relative movement between filter element (or frame part) and filter housing. Also, it is avoided that a part of the projecting sealing element can be pinched between the filter housing and the frame part which could lead to destruction of the sealing element and also to a reduced sealing function. 
         [0015]    According to a further expedient embodiment, the frame part is adhesively connected to the filter element. The adhesive connection is realized by means of a liquid adhesive which, in the not yet cured state, is filled into an adhesive receptacle which is positioned between the frame part and the filter element. In order to prevent that the liquid adhesive flows, prior to curing, along the exterior side of the filter element, a sealing lip is advantageously provided between the frame part and the filter element and delimits the adhesive receptacle between frame part and filter element. The sealing lip prevents an uncontrolled outflow of liquid adhesive during the connecting process between frame part and filter element. After completion of the connection, the sealing lip can even remain on the filter element or the frame part and can be inserted together with these components into the filter housing. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    Further advantages and expedient embodiments can be taken from the further claims, the figure description, and the drawings. 
           [0017]      FIG. 1  shows in a perspective view an air filter device for a motor vehicle, comprising a filter housing and a filter element inserted at the end face of the filter housing and framed by a circumferentially extending frame part by means of which the filter element is secured on the filter housing. 
           [0018]      FIG. 2  shows a parallelepipedal filter element with frame part at an end face. 
           [0019]      FIG. 3  is an illustration corresponding to  FIG. 1  but with an air duct inserted into the frame part of the filter element. 
           [0020]      FIG. 4  shows a section view taken lengthwise through the air filter device according to  FIG. 3 . 
           [0021]      FIG. 5  is an end view of the air filter device in the area of the inflow side of the filter element. 
           [0022]      FIG. 6  shows a vertical section view through the air filter device. 
           [0023]      FIG. 7  shows the detail VII of  FIG. 4  in an enlarged illustration, showing a sealing element at the frame part having correlated therewith a support bead at the housing as well as showing a sealing lip that delimits an adhesive receptacle between frame part and filter element. 
           [0024]      FIG. 8  shows the detail VIII of  FIG. 6  in an enlarged illustration, showing the sealing element at the frame part and the support bead at the housing. 
           [0025]      FIG. 9  shows the detail IX of  FIG. 3  with a securing clip for securing the frame part on the filter housing. 
           [0026]      FIG. 10  shows the detail X of  FIG. 3  with an illustration of the form-fit connection of the air duct on the frame part. 
       
    
    
       [0027]    In the Figures, same components are provided with same reference characters. 
       DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0028]    In the Figures, an air filter device  1  for a motor vehicle, for example for a truck, is illustrated that is used for filtration of combustion air to be supplied to the internal combustion engine. The air filter device  1  has a filter housing  2  and a filter element  3  arranged therein and is framed at the end face in the area of an inflow side by a circumferentially extending frame part  4 . The filter element  3  is embodied as a pleated filter bellows, for example. 
         [0029]    The frame part  4  is located immediately adjacent to the inflow or raw side  5  of the filter element  3  to which air that is to be purified is supplied in the direction of arrow  6 . After filtration, the purified air exits via the clean or outflow side of the filter element and exits the filter housing  2  through an outflow socket  9  in the direction of arrow  7 . The filter element  3  is secured on the filter housing  2  by means of securing clips  8  which connect the frame part  4  with the filter housing  2 . In the mounted state, the frame part  4  engages the end face edge of the filter housing and extends up to the externally positioned circumferential surface of the filter housing in the area adjacent to the insertion opening for the filter element  3 . 
         [0030]    As can be seen in the individual illustration according to  FIG. 2 , the filter element  3  is of a parallelepipedal shape and has a rectangular cross-section. Accordingly, the inflow side  5  of the filter element  3  as well as the frame part  4  are rectangularly embodied also. The frame part  4  projects past the exterior sides of the filter element  3  with a projecting section. The end face of the projecting section of the frame part  4  forms a support surface; this support surface on the frame part  4  is identified with reference character  10 . The support surface  10  is provided at the side which is facing away from the inflow side  5  and, in the mounted state of the frame part  4 , it is resting on the open end face of the filter housing  2 . 
         [0031]    In the mounted state, the frame part  4  is positioned at least substantially outside of the filter housing  2  ( FIGS. 1 ,  3 , and  4 ) and is connected by means of securing clips  8  with the filter housing  2 . The frame part  4  forms in the area of the inflow side of the filter element  3  an air duct receptacle  4   a  ( FIG. 8 ) for an air duct  11  (see  FIGS. 3 ,  4 ) by means of which raw air can be supplied to the air filter device  1  in the direction of arrow  6 . The air duct  11  is inserted into the air duct receptacle  4   a  in the frame part  4  and by means of a form-fit connection  12  is connected form-fittingly to the frame part  4 . 
         [0032]    The form-fit connection  12 , which is illustrated in  FIG. 10  in detail, comprises recesses  13  in the frame part  4  as well as elastic springy locking noses  14  at the exterior side of the air duct  11  facing the end face. The locking noses  14  can be pressed elastically inward in radial direction so that an insertion of the air duct  11  is possible until form-fit locking of the locking noses  14  in the recesses  13  occurs. In the same way, the form-fit connection  12  can be released again by radially pushing the locking noses  14  out of the recesses  13 . The connection between air duct  11  and frame part  4  is realized exclusively by the form-fit connection  12  and thus only between these two components  4 ,  11 . A connection between the air duct  11  and the filter housing  2  is thus not provided. The form-fit connection  12  is located immediately outside of the opening in the filter housing  2  provided at the end face. 
         [0033]    In  FIGS. 7 and 8  a seal arrangement between the frame part  4  and the filter housing  2  is illustrated. The seal arrangement comprises a sealing element  15  which is inserted into a circumferentially extending receptacle  16  at the frame part  4 . The receptacle  16  is open at the end face which is facing the filter housing  2  and is delimited by two legs  17  and  18  that are spaced apart from each other and are monolithically formed with the frame part  4 . 
         [0034]    On the filter housing  2 , there is a support bead  19  which interacts with the sealing element  15 . The support bead  19  can be monolithic with the filter housing  2  or designed as a separate component which is made of a different material than the filter housing but is connected fixedly with the filter housing  2 . The support bead  19  has a mushroom shape in cross-section wherein a narrow stem of the support bead  19  is facing the sealing element  15  and is in contact therewith. The stem or leg of the support bead  19  has a smaller width compared to the sealing element  15  and loads the sealing element  15  centrally. This embodiment is sufficiently flow-tight; moreover, the risk of shearing off in the area of the sealing element  15  is significantly reduced. The sealing element  15  terminates advantageously at the end face of the legs  17 ,  18  so that no shearing off in the area of the end face of the sealing element  15  can occur even for a relative movement between the frame part  4  and the filter housing  2 . 
         [0035]    The support bead  19  projects past the immediately neighboring walls of the filter housing  2  and presses into the yielding material of the sealing element  15 . The end face of the stem of the support bead  19  which is projecting into the sealing element  15  is rounded. 
         [0036]    Moreover, in  FIGS. 7 and 8  in combination with  FIGS. 5 and 6 , it can be seen that the frame part  4  is adhesively connected with the filter element  3 . The adhesive connection is realized by means of a circumferentially arranged adhesive fill  20  which is filled into an adhesive receptacle  21  between the frame part  4  and the filter element  3 . Filling is realized in the manufacturing process while the adhesive is in the liquid state with subsequent curing. In order to avoid that during the curing process adhesive  20  will flow out of the adhesive receptacle  21  in downward direction, a sealing lip  22  ( FIGS. 5 ,  7 ) is arranged at the adhesive receptacle  21 . The adhesive receptacle  21  is substantially triangular in cross-section. The sealing lip  22  is connected fixedly with the frame part  4  and remains on the frame part  4  even in the cured state of the adhesive  20 . 
         [0037]    The adhesive receptacle  21  is inwardly displaced in radial direction relative to the receptacle  16  for receiving the sealing element  15  and is separated by the leg  18  from the receptacle  16  for the sealing element  15 , wherein the leg  18  at the same time delimits the adhesive receptacle  21  laterally. At the base of the leg  18 , the sealing lip  22  is arranged which is extending at a slant inwardly and delimits the pointedly tapering side of the adhesive receptacle. The free end face of the sealing lip  22  is positioned at the exterior circumferential surface of the filter element  3 . 
         [0038]    The sealing lip  22  is arranged at the two oppositely positioned longitudinal sides of the rectangular frame part  4  ( FIG. 5 ). At the narrow sides of the filter element  3  there is a lateral band  23 , respectively, which is connected fixedly with the filter element  3  and, in the area of the narrow sides, delimits the adhesive receptacle  21  at its pointedly tapering side ( FIGS. 5 ,  6 , and  8 ). 
         [0039]    In  FIG. 9 , the support of the frame part  4  on a counter contact surface on the filter housing  2  as well as the connection by means of the securing clips  8  is illustrated. The projecting section of the frame part  4  which is radially projecting past the filter element  3  has a support surface  10  (see also  FIG. 2 ) which is facing away from the inflow side and, in the connected state, is resting on the counter contact surface  24  on the filter housing  2 . The securing clip  8  is pivotably supported on the exterior surface of the filter housing  2  and engages in the tightened state the section of the filter housing  2  with the counter contact surface  24  as well as the projecting section of the frame part  4  with the support surface  10 . The securing clip  8  is embodied to be elastic; in the tightened state a securing section  8   a  engages across a step on the frame part  4  where the support surface  10  is arranged and forces thus the frame part  4  with the support surface  10  against the counter contact surface  24  on the filter housing  2 . 
         [0040]    While specific embodiments of the invention have been shown and described in detail to illustrate the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.