Patent Publication Number: US-2020284228-A1

Title: Filter Arrangement

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 15/597,554 having a filing date of 17 May 2017, which claims a priority date of 18 May 2016 based on prior filed German patent application No. 10 2016 006 042.5, the entire contents of the aforesaid US application and the aforesaid German patent application being incorporated herein by reference to the fullest extent permitted by the law. 
    
    
     TECHNICAL FIELD 
     The present invention concerns a filter housing and a filter arrangement, in particular an air filter arrangement. 
     BACKGROUND OF THE INVENTION 
     DE 196 25 443 A1 discloses a filter housing for an exchangeable plate-shaped filter element that is comprised of a first and a second housing part. In this context, a seal extending circumferentially about the filter element is axially compressed between the housing parts. 
     WO 2009/150167 A1 discloses a filter housing for a filter insert in which two assembled housing parts are detachably coupled to each other by a locking connection device. In addition, for increasing the safety, connecting cutouts aligned with each other are introduced into the housing parts and are provided for receiving additional connecting elements. Screws are mentioned in particular as connecting elements. In WO 2009/150167 A1, a seal circumferentially extending about the filter element is radially compressed. Therefore, locking connections as well as connections that are aligned with each other and comprise connecting elements are required. 
     SUMMARY OF THE INVENTION 
     It is therefore the object of the present invention to provide an improved filter housing. 
     Accordingly, a filter housing for receiving a filter element is proposed wherein a sealing element is correlated with the filter element and extends circumferentially about the filter element. The filter housing comprises a first housing part and a second housing part which can be joined and separated from each other in an axial mounting direction. In this context, a first rim section of the first housing part and a second rim section of the second housing part form a receiving area for the sealing element in such a way that the sealing element is radially clamped between the rim sections. Moreover, a snap connecting device for axially bracing the housing parts is provided which is integrally formed such on the housing part that a contact force or clamping force acting in radial direction by means of the rim sections on the sealing element is decoupled from the snap connecting device. 
     The two housing parts can be axially coupled with each other and decoupled in a simple way by means of the snap connecting device. By decoupling radially acting contact forces which are exerted on the seal, for example, by a frame or by rim sections of the housing parts, from forces which occur as a result of the axial assembly at the snap connecting device the latter can therefore be designed particularly simply. 
     In embodiments, the respective housing part and the respective part of the snap connecting device are formed monolithic of a material, in particular of a plastic material. 
     Preferably, the housing parts are axially secured on each other exclusively by means of the snap connecting device. In embodiments, additional securing means can be provided however. 
     Also, by decoupling the sealing forces from the bracing forces for the housing parts, improved robustness of the snap connecting device is gained. The latter can be designed, for example, to be sufficiently flexible or elastic so that even at low temperatures the employed material does not become too brittle and does not tear under deformation when installing or removing the filter element. 
     In embodiments, the filter housing and the snap connecting device are made of a plastic material that becomes brittle at low temperatures, for example, below 0° C. By decoupling the clamping forces from the bracing forces in radial or axial direction at the housing, the assembly reliability is improved. 
     In embodiments of the filter housing, a springy snap hook of the snap connecting device correlated with the first rim section is spaced outwardly in radial direction from the first rim section in such a way that a contact force or clamping force applied by the rim section on the sealing element inwardly in radial direction is decoupled from the snap hook. 
     A snap hook can be provided in particular to be flexible and radially movable such that forces exerted by the housing parts or the rim sections on the sealing element are not transmitted onto the snap hook. In this way, the snap hook is less stressed and has a longer service life. 
     In embodiments, the snap hook is designed to be springy in radial direction. Alternatively or additionally, the snap hook can also be designed to be springy in axial direction. 
     The first and the second rim sections comprise, for example, a circumferentially extending sealing stay. The sealing stays are radially displaced to each other in the mounted state and delimit the receiving space such that the sealing element is clamped radially between the sealing stays. In this way, a radial sealing action by means of the sealing element and the sealing stays is provided. In addition, optionally axial forces can be transmitted to the sealing element. For this purpose, projecting stays or sealing contours can be provided, for example, in or on the receiving area. 
     In embodiments, the first and the second rim sections each comprise a circumferentially extending sealing stay and the sealing stays are radially displaced such that they laterally delimit the receiving area. The sealing element is then clamped between the sealing stays. Preferably, the sealing stays are not part of the snap connecting device so that a reliable decoupling of contact or clamping forces for the radial sealing action from an axial joining action of the housing parts is realized. 
     In embodiments, the snap connecting device can be provided with a snap hook and a holding section with a cutout. The snap hook engages behind the holding section in the mounted state, preferably by form fit. It is conceivable that the filter housing comprises several snap connecting devices. Preferably, snap connecting devices are provided exclusively radially on the rim in order to axially connect the two housing parts with each other. Further connecting means for the housing parts are preferably not provided. 
     The snap hook can be arranged in particular so as to be spaced outwardly in radial direction relative to the outer sealing stay. By providing a spacing between the snap hook and the sealing stay, a radial movability of the snap hook relative to the housing part is provided by the spacing, for example. 
     In embodiments, the filter housing comprises a snap hook that is U-shaped. It is conceivable that a U-shaped snap hook comprises a first leg, a spring section, and a second leg. For example, the first leg is spaced apart by means of a radial stay from a housing wall and extends axially along the housing wall of the first housing part. The radial stay reduces the effect of radial contact forces on the snap hook that is part of the snap connecting device. 
     In a preferred embodiment, the snap connecting device includes an elastic U-shaped snap hook with an elastic spring section in a curved U base between the first and the second legs and a radial stay secured on and projecting radially outwardly from a housing wall and is elastically deformable. In this embodiment, the curved U base spring section between the first and second legs as well as an L-shaped or U-shaped curved bridge connecting the U-shaped snap hook to the radial stay are both elastically bendable, the spring section and the bridge can absorb the forces under elastic deformation, which occur during the assembly and dismantling, opening and closing the U-shaped snap hook to connect the housing parts. A undesirable force introduction to the housing wall is avoided as much as possible, particularly in cold weather when the force required to open the snap connecting device is elevated due to material properties of, for example, plastics, and may otherwise cause damage to or breakage of housing or alternately the connecting device in such conditions. Due to the two elastically adjustable areas of the bridge and the spring section of the snap hook, an assembly and dismantling of the filter housing is possible even at low temperatures and/or a brittleness of the material without the risk of damage. 
     In embodiments, the second leg has a locking nose for engagement in the cutout of the holding section. Moreover, the first leg, the spring section, and the second leg preferably force the locking nose in the mounted state resiliently in radial direction outwardly into the cutout. Alternatively or additionally, the first leg, the spring section, and the second leg are designed such that the two legs, when considering the mounted state, can be reversibly moved inwardly in radial direction in order to move the locking nose out of the cutout. 
     The snap connecting device of a further embodiment is designed such that the locking nose, upon joining of the housing parts in the mounting direction, slides automatically in radial direction into the cutout. For example, the locking nose and a corresponding counter contour of the cutout can be profiled such that the locking nose automatically snaps in and engages. 
     In embodiments, the second housing part has a guide section which is projecting away from the housing wall and which upon joining and/or separating of the housing parts in the mounting direction pushes the first leg outwardly in radial direction and/or blocks an axial movement of the snap hook relative to the other housing part. The guide section can act like a rib on the oppositely positioned snap hook in such a way that the latter, upon axially moving apart the housing parts, is pushed into the cutout of the holding section. One can say that the snap hook is blocked by the rib such that without an additional manipulation process the snap hook cannot be moved past the rib. 
     Moreover, a filter arrangement with a filter housing, as explained above or in the following, as well as with a filter element and with a sealing element is proposed. The sealing element is, for example, radially compressed in the receiving space and the second leg comprises a manipulation section for moving the locking nose out of the cutout inwardly in radial direction. In this way, removal of the filter element or demounting of the filter housing by taking apart the two housing parts is simplified. 
     Preferably, the filter housing and the filter arrangement serve for purifying combustion air for the motor of a motor vehicle. Conceivable are however also other applications. The filter arrangement and in particular the filter element are preferably designed to filter fluids, for example, air or other gases, liquids, in particular liquid operating media of a vehicle, in particular of a motor vehicle, such as oil, water, diesel, gasoline, kerosene or urea solution. In particular, the filter element is an air filter element. The filter arrangement can be used in motor vehicles, watercraft, rail vehicles, agricultural vehicles, construction machinery, aircraft or the like. Moreover, the filter arrangement can also be used in immobile applications, for example, in building technology. The filter element can comprise a folded filter medium. 
     Further possible implementations of the filter arrangement comprise also combinations, not explicitly mentioned, of features or configurations described above or in the following with respect to embodiments. In this context, a person of skill in the art will also add individual aspects as improvements or supplements to the respective basic form of the filter arrangement. 
     Further configurations of the filter arrangement are subject matter of the dependent claims as well as of the embodiments of the filter arrangement described in the following. Moreover, the filter arrangement will be explained in more detail with the aid of embodiments with reference to the attached Figures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a housing part of an embodiment of a filter housing. 
         FIG. 2  shows a perspective view from below of the housing part of  FIG. 1 , wherein an inserted filter element is visible. 
         FIG. 3  is a section view of an embodiment of a filter housing with the housing part of  FIG. 1  and a housing bottom part. 
         FIG. 4  is a section view of an embodiment of a filter arrangement with the filter housing of  FIG. 3  and inserted filter element. 
         FIG. 5  is a perspective detail view of a snap connecting device for the filter housing according to  FIGS. 3 and 4 . 
         FIG. 6  shows a section view of the snap connecting device of  FIG. 5   
         FIGS. 7A and 7B  show the snap hook of the snap connecting device in section view, wherein  FIG. 7A  shows a tensioned state and  FIG. 7B  shows an untensioned state. 
         FIG. 8  is a perspective detail view of the snap connecting device with the snap hook engaged at the cutout of the holding section. 
     
    
    
     In the Figures, same reference characters identify same or functionally the same elements, inasmuch as nothing to the contrary is indicated. 
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     In the Figures, an embodiment of a filter housing as well as of a filter arrangement with a filter element and detail illustrations of embodiments for snap connecting devices on a filter housing are illustrated. In the following, the embodiment of the filter housing  1  or of the filter arrangement are described together. For this purpose, a perspective view of a housing top part  3  from above with snap connecting devices  11  is illustrated in  FIG. 1 .  FIG. 2  shows a perspective view from below into the housing top part  3 , as illustrated in  FIG. 1 , wherein an inserted filter element  2  is visible. In  FIG. 3 , a section view of a filter housing  1  with the housing top part  3 , as indicated in  FIGS. 1 and 2 , and with a housing bottom part  4  is illustrated.  FIG. 4  shows a filter arrangement with a corresponding filter housing  1 , as illustrated in  FIG. 3 , with inserted filter element  2 . 
     In  FIGS. 3 and 4 , it can be seen that a housing bottom part  4  and a housing top part  3  can be joined and, for opening, moved apart from each other again along an axial mounting direction M. In  FIGS. 3 and 4 , a filter housing axis or filter arrangement axis A is illustrated in dash-dotted line. The filter housing  1  serves for receiving a filter element  2  in the housing interior. A filter element  2  comprises, for example, a parallelepipedal fold pack of a filter material or filter medium  5 . In order to provide a rim-side sealing action relative to the filter housing  1 , so that a raw fluid area RO and a clean fluid area RE are separated from each other, the filter element  2  comprises a circumferentially extending frame-shaped sealing element  6 . The sealing element  6  may comprise, for example, a PUR foam. The circumferentially extending sealing element  6  is in this context flexible and compressible to a certain extent so that in particular a radial sealing action relative to the filter housing  1  can be realized. 
     In this context, radial is understood substantially as a direction R which is extending in the plane of the filter element  2  and passes through the filter housing  1  from the interior to the exterior or from the exterior to the interior. In the Figures, a radial direction is identified by R. 
     One can recognize in  FIG. 1  and  FIG. 2  that the cover or the top part  3  of the filter housing  1  comprises a connecting socket  22  for clean air. In operation of the filter arrangement, raw air flows, for example, into the lower housing area as raw air area RO through a connecting socket, which is not visible in the Figures, and through the filter element  2  into the clean air area RE which is substantially enclosed by the cover or housing top part  3 . Upon passing through the filter medium  5 , particles are retained so that in the orientation of the Figures in the upper clean air area RE at the connecting socket  22  the purified air can be tapped and supplied as combustion air to the respective motor of a motor vehicle. The two housing parts  3 ,  4  may comprise further reinforcement ribs  23  that mechanically reinforce the housing that is, for example, made of plastic material. In axial direction, the housing parts  3 ,  4  are secured by means of snap connecting devices  10 . In  FIGS. 1 and 2 , one can see, for example, four snap connecting devices  10  or the corresponding snap hooks  11 . The snap hooks  11  can engage cutouts  13  of corresponding holding sections  12  of the lower housing part  4 . In  FIG. 3 , the detached state of the snap connecting device  10  is illustrated and in  FIG. 4  the mounted state, i.e., the closed filter housing  1  with the filter element  2 , is illustrated. In this context, the locking noses  18  of the snap hooks  11  engage behind the cutouts  13  of the respective holding section  12 . 
     In addition to the axial bracing of the two housing parts  3 ,  4  with each other by means of the snap connecting devices  10 , a radial sealing action of the filter element  2  relative to the rim sections of the housing parts  3 ,  4  is realized. For this purpose, a sealing stay  7  as a first rim section of the first upper housing part  3  is illustrated. The sealing stay  7  is extending downwardly in the orientation of  FIGS. 3 and 4 . Opposite the sealing stay  7 , a second rim section  8  of the lower housing part  4  is provided which is part of the housing wall and can also be referred to as a sealing stay. In  FIG. 3 , one can see that the two rim sections  7 ,  8  are radially spaced apart from each other. The area between these two rim sections  7 ,  8  serves as receiving space  9  for the sealing element  6 . This can be seen in particular in  FIG. 6 . The sealing element  6  is radially compressed between the sealing stays  7  and  8  and thus provides a sealing action. The radial compression results from the stiffness of the rim sections forming the sealing stays  7 ,  8  of the housing parts  3 ,  4 . 
     A transfer of such radial forces to the snap connecting device  10  is prevented. In  FIGS. 5 to 8 , detail illustrations of the embodiment of a snap connecting device  10 , as it is arranged on the filter housing  1 , is illustrated.  FIG. 5  shows a perspective detail view of a U-shaped snap hook  11 . The snap hook  11  is integrally formed on the housing top part  3 .  FIG. 6  shows a cross section view of a snap connecting device  10  in detail. As has already been explained in connection with  FIGS. 3 and 4 , a receiving area  9  for the sealing element  6  which is circumferentially extending about the filter medium  5  is provided by the two sealing stays  7 ,  8 . In the orientation of  FIG. 6 , the filter housing interior is located to the right and the exterior space is located to the left. A radial stay  17  that begins at the sealing stay  7  is extending in radial direction from the interior to the exterior and spaces apart the snap hook  11  in outward direction. The radial stay is connected to an outer end of the radial flange  7 A that is formed on and projecting radially outwardly from the wall of the housing  3 . The housing  4  has a flange  8 A formed on and projecting radially outwardly from the housing  4 . As shown in  FIG. 6 , the sealing stay  7  contacts against the flange  8 A at the bottom of the receiving area  9 . 
     The snap hook  11  comprises accordingly a first inner leg  14  which is passing from a curved section  15  into a second leg  16 . Moreover, one can see the locking nose  18  which is projecting outwardly in radial direction and a manipulation section  21  by means of which in particular the second leg  16  with the locking nose  18  can be moved inwardly in radial direction. Moreover, the holding section  12  formed integrally on the lower housing part  4  is indicated. In the illustration of  FIG. 6 , the locking nose  18  engages behind a cutout in the holding section  12  and secures axially, i.e., in the mounting direction M, the two housing parts  3 ,  4  relative to each other. 
     With the aid of  FIGS. 7A and 7B , the snapping process for mounting can be explained. One can see in  FIG. 7A  a tensioned state of the snap hook  11 , i.e., the locking nose  18  is positioned, viewed in axial direction, outside of the cutout  13  of the holding section  12 . By means of the first and second legs  14 ,  16  a radial force is acting on the spring section  15 . This can be realized, for example, by means of the manipulation section  21  by movement from the left to the right in the orientation of  FIGS. 7A and 7B . When, as illustrated in  FIG. 7B , the upper housing part  3  (compare  FIG. 6 ) is moved downwardly, the locking nose  18  snaps into engagement with the holding section  12  as a result of the spring action of the spring section  15 . This is illustrated in  FIG. 7B . The snap hook  11  is then in its untensioned state without additional or with only minimal force acting on its basic shape. 
     The snap connecting device  10  has a U-shaped snap hook  11  with an elastic spring section  15  in a curved U base between the first leg  14  and the second leg  16  and an L-shaped curved bridge  17 , which is elastically deformable and is spaced radially outwardly away from the housing wall at distance DW. Under elastic deformation, the spring section  15  and curved bridge  17  elastically deflect to take up the forces that occur during assembly and dismantling to connect the housing parts. Rather than attaching the U-shaped hook  11  directly to the housing wall, it has been found that spacing the elastic spring section  15  having a curved U base and the curve bridge  17  outwardly away from the housing  3  wall at a distance DW from the housing  3  wall  3  (see  FIG. 7A ) is particularly advantageous as this spacing and second elastic section has been found to surprisingly and significantly reduce force loading on the housing wall by absorbing the forces in both the elastic spring section  15  in a curved U base between the first leg  14  and the second leg  16  and in an L-shaped or U-shaped curved bridge  17 , advantageously thereby preventing breakage of the housing due to forces applied to open of close the snap connecting device  10 , particularly in cold weather/temperature conditions when the material of the housing  3  and the snap connecting device  10  may become more brittle due. 
     In  FIG. 8 , one can see in perspective view from below an embodiment of a snap connecting device  10 . In order to assist movement of the snap hook  11  outwardly in radial direction, a guide rib  20  oriented in radial outward direction away from a housing wall  19  of the lower housing part  4  is provided. In the orientation of  FIG. 8 , the guide rib  20  presses from the right to the left against the inner first leg  14 , hidden in the illustration, of the snap hook  11 . In this way, the outer second leg  16  with the locking nose  18  is forced into the opening or cutout  13  of the holding section  12 . Accordingly, a reliable automatic snap connection and locking action in axial direction are realized. As shown in  FIG. 8 , the holding section  12  has two ribs  12 A,  12 B which are spaced apart and connected to the housing  4 . As shown in  FIG. 8 , the guide rib  20  is arranged between the ribs  12 A,  12 B. 
     When taking apart or demounting the housing parts  3 ,  4  from each other, they are moved relative to each other in axial direction. The rib  20  has preferably a shape such that the rib  20  blocks the snap hook  11  and the operator must additionally move the snap hook past the rib  20 , for example, by means of a manipulation section  21 , in order to remove the locking nose  18  from the cutout  13 . 
     The decoupling of forces axially acting on the elements of the snap connecting device from forces radially acting on the sealing element enables a simpler configuration of the snap connecting device. Accordingly, material can be saved and a more flexible configuration, in particular of the snap hook, can be achieved. The U-shaped configuration is particularly beneficial and flexible in this context. However, also other snapping mechanisms are conceivable. In this way, even at low temperatures mounting and demounting of filter housings can be reliably performed. 
     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. 
     LIST OF REFERENCE CHARACTERS 
     
         
           1  filter housing 
           2  filter element 
           3  housing top part (cover) 
           4  housing bottom part 
           5  filter medium 
           6  sealing element 
           7 ,  8  sealing stay/rim section 
           7 A radial stay 
           8 A flange 
           9  receiving area 
           10  snap connecting device 
           11  snap hook 
           12  holding section 
           12 A, 12 B ribs 
           13  cutout 
           14  first leg 
           15  spring section 
           16  second leg 
           17  radial stay 
           18  locking nose 
           19  housing wall section 
           20  guide rib/blocking means 
           21  manipulation section 
           22  connecting socket 
           23  reinforcement rib 
         A housing axis 
         D spacing 
         M mounting direction 
         R radial direction 
         RO raw air area 
         RE clean air area