Technical field

[0001] The invention relates to a filter element, in particular an air filter element, having a filter medium body featuring an at least partially circumferential edge element on at least one circumferential side.

Background art

[0002] A filter element is known from DE 10 2009 042 588 A1 featuring a cuboidshaped filter medium body designed as a filter bellows and consisting of a folded filter medium. On each of the two opposing front faces is a sideband on the filter medium body designed as a non-woven band and projecting slightly beyond the lateral surfaces of the filter medium body. At the end of each sideband is a frame element projecting beyond the circumferential side of the filter medium body and having an indicating function for the correct installation of the filter element in a filter apparatus.

[0003] Also known from WO 2009/006957 A1 is a filter element having a fold-shaped filter medium body disposed in the shape of a cuboid, the opposing fold front sides of which are each covered by a non-woven strip. The non-woven strips are rectangular and project beyond one side of the filter medium body.

Disclosure of the invention

[0004] The object of the invention is to specify a constructively simple design for a filter element characterized by a well-defined installation position and at the same time improved flow guidance to or from the filter element.

[0005] This object is solved according to the invention with the characteristics of claim 1 . The subclaims specify appropriate further developments.

[0006] The filter element according to the invention is designed, for example, as an air filter element, for example for filtering the combustion air to be supplied to an internal combustion engine or fuel cell, or the air to be supplied to a vehicle passenger compartment, or generally for filtering air containing contaminant particles. The filter element is preferably used for filtering gaseous fluids. However, use of the filter element for filtering liquid fluids can also be envisaged. [0007] The filter element comprises a filter medium body made of a filter medium, on which the filtering of the fluid to be cleaned, in particular air, is taking place. The filter medium body features an inflow side forming the raw side and an outflow side forming the clean side. The flow through the filter medium body occurs from the inflow side to the outflow side.

[0008] The filter medium features in particular at least one particle filtration layer, which can be made of a synthetic non-woven fabric. Furthermore, it is possible for the filter medium to feature at least one adsorption filter layer, in particular comprising an adsorbent, in particular in the form of an adsorbent granular immobilized with respect to the particle filtration layer. The adsorbent can in particular be an activated carbon. Having at least one adsorption filter layer can remove certain harmful gases, such as NOx, SOx NH3 and/or CO, and/or odors.

[0009] Advantageously, the filter medium body is cuboid-shaped at least sectionwise, so that the inflow and outflow sides are disposed parallel to each other. However, other geometric shapes for the filter medium body can also be considered, in particular blockshaped or box-shaped embodiments differing from the cuboid shape, for example embodiments having non-parallel inflow and outflow sides.

[0010] On at least one circumferential side, the filter medium body features an in particular strip-shaped edge element at least partially surrounding the circumferential side. The edge element is in particular firmly connected to the circumferential side of the filter medium body, for example glued or welded or injection-molded to the filter medium body, and advantageously seals the circumferential side of the filter medium body in a flow-tight manner.

[0011] The edge element on the circumferential side of the filter medium body features at least one projection portion with which the edge element projects beyond the inflow or outflow side of the filter medium body. The projection portion of the edge element extends partially or completely along a circumferential side of the filter medium body and features a variable projection beyond the inflow or outflow side along this circumferential side. The projection portion features different projections beyond the inflow or outflow side of the filter medium body in two portions facing away from each other. The feature "portions facing away from each other" is to be understood with respect to an extension direction of the circumferential side, in such a way that - in other words - portions of the projection portion facing laterally away from each other are meant.

[0012] The advantage of this embodiment is that the projection of the projection portion beyond the inflow or outflow side of the filter medium body provides improved flow guidance of the fluid to be cleaned. The improved flow guidance can refer to the still uncleaned, incoming fluid or to the already cleaned fluid flowing away from the filter medium body. For example, if the projection is located on the inflow side of the filter medium body, the incoming fluid can be directed towards the filter medium body with the aid of the projection portion of the edge element. This flow guidance is achieved with the assistance of the projection portion disposed directly on the filter medium body belonging to the filter element together with the filter medium body in such a way that the improved flow guidance is achieved using means of the filter element. Additional flow-guiding means can be provided, if necessary, on a frame part or the filter housing which accommodates the filter element. If the projection portion is located on the outflow side of the filter medium body, a directed discharge of the fluid passing through the filter medium body is achieved.

[0013] Furthermore, it is advantageous that the projection can be used to achieve a defined installation position of the filter element in an accommodating filter housing. The installation position of the filter element can be defined with the assistance of the variable projection of the projection portion.

[0014] Another advantage is that the variable projection supports the achievement of a defined installation position in an accommodating filter housing or frame part. The filter element can be inserted into the filter housing or frame part in such a way that, in the final installation position, the projection portion of the edge element comes into contact with an accommodating component. The variable projection ensures a high- precision fit or a backlash-free reception and position in the desired installation position.

[0015] In embodiments, the projection portion can feature different projections beyond the inflow or outflow side of the filter medium body in end regions facing away from each other. By "end regions" are meant herein end portions of the projection portion having a certain width and facing away from each other in the direction of the respective circumferential side. In particular, it can be provided that the projections at ends facing away from each other in the direction of the respective circumferential side are different. However, it can also be provided that the identical projections or no projections at all are present at the respective ends, as long as different projections are present in the end regions of the projection portion. The dimensions of the end regions - measured from the respective end of the edge element - can, in an exemplary fashion, be between 0 mm and 30 mm, in particular between 0 mm and 10 mm.

[0016] According to an advantageous embodiment, the projection, with which the projection portion projects beyond the inflow or outflow side of the filter medium body, increases continuously along the circumferential side of the filter medium body on which the edge element is located. The increase can be progressive, degressive or, according to a preferred embodiment, continuous or ramp-shaped. Accordingly, the edge element can feature a trapezoidal or triangular shape in top view. Due to the continuous increase, the projection is lowest at one end of the edge element and highest at the opposing end of the edge element. The maximum projection ensures a targeted flow supply in case of projection at the inflow side or a targeted flow discharge in case of projection at the outflow side.

[0017] In other embodiments, the projection, with which the projection portion projects beyond the inflow or outflow side of the filter medium body, can also rise discontinuously along the circumferential side of the filter medium body where the edge element is located, i.e. , for example, it can have a step-shaped or staircase-shaped projection.

[0018] Alternatively or additionally, it is possible for the projection portion projecting beyond the inflow or outflow side of the filter medium body with a variable projection to be slotted one or more times over the extent of the circumferential side. In other words, the projection portion can be designed to be interrupted over the extent of the circumferential side.

[0019] In embodiments, a second edge element having at least one projection portion can be disposed on the filter medium body on a further circumferential side opposite the at least one circumferential side. [0020] In this connection, the projection portion of the second edge element can feature a variable projection beyond the inflow or outflow side of the filter medium body along the further circumferential side of the filter medium body on which the projection portion is located. The projection portion of the second edge element features in two portions facing away from each other different projections beyond the inflow or outflow side of the filter medium body. In particular, the projection portion of the second edge element can feature different projections beyond the inflow or outflow side of the filter medium body in end regions facing away from each other.

[0021] In particular, two edge elements, each having a projection portion, can be present laterally opposing each other on the identical side of the filter medium body - either on the inflow side or on the outflow side. In a preferred embodiment, the edge elements including their respective projection portions are disposed mirror- symmetrically with respect to one another. This enables the filter element to have identical flow and insertion conditions at its two opposing side edges.

[0022] In particular, the projection of the projection portion of the second edge element and the projection of the projection portion of the first edge element can be present on the inflow side of the filter medium body. Because of this, a particularly advantageous flow guiding effect on the inflow side is achieved.

[0023] According to a yet further advantageous embodiment, a further edge element is disposed on a front face of the filter medium body which extends at an angle with respect to the circumferential side with the first edge element. In particular, it is orthogonal with respect to the first edge element. The further edge element also features a projection portion having a preferably constant projection. In a preferred embodiment, the projection of the projection portion of this further edge element corresponds to the maximum projection of the first edge element. The first edge element featuring the variable projection can be formed in one piece with the further, angularly extending edge element featuring a constant projection. In a further embodiment, the first and second edge elements, which are on opposing edge sides and feature a variable projection each, are designed in one piece with the connecting further edge element on the front face of the filter medium body. However, the first edge element, the second edge element and the further edge element can also be designed separately from one another and, in particular, be connected individually to the filter medium body, which is advantageous in particular in corner areas for easier production.

[0024] In embodiments, the further edge element can form a corner with the first edge element and/or the second edge element and, in particular, be connected thereto in a corner area.

[0025] In a further advantageous embodiment, the first edge element features a first projection portion on one side of the filter medium body and furthermore a second projection portion extending to the opposing side of the filter medium body. Thus, the first projection portion of the edge element is adjacent either to the inflow side or to the outflow side and the second projection portion of the same edge element is adjacent to the opposing side, i.e. the outflow side or the inflow side. In particular, the first projection portion can be present on the inflow side and the second projection portion can be present on the outflow side.

[0026] In this connection, it can be appropriate for the second projection portion to feature a constant projection that is significantly smaller, in particular several times smaller, than the maximum projection of the first projection portion. The second projection portion of the edge element allows engagement in a corresponding groove in the accommodating filter housing or in the accommodating frame part. The second projection portion thus serves to guide and secure the filter element in the accommodating filter housing or frame part. In a preferred embodiment, in the case of two laterally opposing edge elements each provided with a projection portion having a variable projection, a second projection portion is disposed on the opposite side respectively, and features a constant projection. In other words, preferably both the first and second edge elements each comprise a first and a second projection portion. This is advantageous because it is possible to realize an optimized guidance of the filter element in a housing by means of second projection portions disposed opposingly on the filter medium body.

[0027] According to a yet further advantageous embodiment, the filter medium body is designed as a filter bellows made of a folded filter medium, wherein the edge element and/or the second edge element is disposed on a front face of the filter bellows. In the preferred embodiment having two laterally opposing edge elements, they are correspondingly located on the opposing front faces of the filter bellows. The edge element and/or the second edge element can in particular be fastened to fold front edges of the filter bellows.

[0028] According to a yet another embodiment, the edge element is made of a nonwoven fabric or comprises at least one non-woven fabric. The non-woven fabric can be glued or welded to the circumferential side of the filter medium body, in particular in a flow-tight manner, in order to close the corresponding front face of the filter medium body in a flow-tight manner. As an alternative, the first edge element, the second edge element and/or the further edge element can also be provided by overmolding the filter bellows.

[0029] The invention furthermore relates to a filter apparatus having a filter element as described above and having a filter housing or a frame part for accommodating the filter element. The filter housing or the frame part is, for example, inserted into a motor vehicle, in particular in the front area, for example adjacent to a radiator of the motor vehicle. In embodiments, the filter apparatus can be a vehicle-integratable outdoor air purifier designed to filter the ambient air, which means that both the raw side of the filter element and the clean side of the filter element communicate fluidically with the environment.

[0030] The filter housing can in particular feature a receiving shaft into which the filter element can be inserted along an insertion direction and removed again along this direction.

[0031] In embodiments, the filter element can be insertable along an insertion direction into the filter housing in a drawer-like manner. A drawer-like insertion of the filter element offers advantages when replacing the filter element, for it is a guided movement making it easier for a service staff member to position the filter element correctly in the filter housing.

[0032] In embodiments in which the filter apparatus is a vehicle-integratable outdoor air purifier, the insertion direction can coincide with a vehicle vertical axis in a predetermined mounting position. As an alternative, the insertion direction can extend in a predetermined mounting position with at least one component along the vertical axis of the vehicle.

[0033] According to a further advantageous embodiment, the filter housing features at least one holding device, in particular at least one holding bracket, which supports the filter element in the inserted state in the filter housing on the projection portion. If necessary, two holding brackets disposed at a distance from one another can be provided in the filter housing in order to support the inserted filter element at different positions. In embodiments, the holding device can feature at least one holding surface on which the projection portion is supported. In particular, the holding surface can lie at an angle with respect to the insertion direction, in such a way that in particular a ramp-shaped projection can be supported thereon. The projection portion that can rest on the holding device is in particular the first projection portion that features a variable projection beyond the inflow or outflow side of the filter medium body along the circumferential side of the filter medium body. The at least one holding device can in particular be present on an inflow side of the filter element.

[0034] According to a yet further advantageous embodiment, the filter housing features at least one guide groove into which a projection portion of the edge element projects. In this connection, it is in particular the second projection portion of the edge element, which projects only slightly beyond one side of the filter medium body and features a constant projection. The guide groove in the filter housing guides the filter element into or out of the housing during insertion or removal and, in the inserted state, holds the filter element in a secure, backlash-free position in the filter housing. The guide groove extends in particular in the insertion direction. In embodiments, the filter housing can feature two guide grooves in which the second projection portions of the first and second edge elements engage when the filter element is in the inserted state. This allows the filter element to be guided on both sides making it even easier to install and/or to remove the filter element.

[0035] In a further advantageous embodiment, there is a cover element on one edge side of the filter element, which can be connected to the filter element. In the assembled state, the cover element closes off with the filter housing or the frame part into which the filter element is inserted. The cover element can be present in particular on the front face of the filter element or filter medium body on which the further edge element is present. The cover element can in particular be present against a side of the filter element that lies at the rear in the insertion direction.

[0036] The cover element protects the filter element against external influences and can also seal the relevant edge side of the filter medium body in a flow-tight manner. The cover element can be firmly connected to the filter element in such a way that, when the filter element is inserted, the cover element rests on the opening in the filter housing or frame part into which the filter element is inserted. A separate embodiment of filter element and cover element is also possible; in this case, the cover element is placed on the filter housing or on the frame part after insertion of the filter element. As an alternative or additionally, the cover element can be detachably connected to the filter housing or frame part in the mounted state, for example by means of a screw and/or snap-fit connection.

[0037] Finally, the invention relates to a motor vehicle having a filter apparatus as described above. The filter apparatus is in particular installed in a front area of the motor vehicle in a surrounding area of at least one heat exchanger, in particular a water cooler. In embodiments, the filter apparatus is installed upstream of at least one heat exchanger, as seen in the direction of travel. In embodiments, the filter apparatus is installed in the vehicle in such a way that the first projection portion of the edge element and/or of the second edge element faces forward in the direction of travel. In this context, "direction of travel" means in particular a forward direction of travel as intended.

Description of drawings

[0038] Further advantages and appropriate embodiments can be taken from the claims, the description of the figures and the drawings. It is shown in:

[0039] Fig. 1 in exploded view a filter apparatus for air filtration, having a filter housing, a filter element and a cover attachable to the filter element,

[0040] Fig. 2 the filter apparatus with the filter element partially introduced into the filter housing, [0041] Fig. 3 the filter apparatus with the filter element completely introduced into the filter housing,

[0042] Fig. 4 a rear view of the filter apparatus,

[0043] Fig. 5 a sectional view according to section line V-V of Fig. 4,

[0044] Fig. 6 a sectional view according to section line VI-VI of Fig. 4, [0045] Fig. 7 the detail VII of Fig. 6 in an enlarged view.

[0046] Identical components in the figures have the same reference numerals.

Mode(s) for invention

[0047] The Figures show a filter apparatus 1 which can be used in an exemplary fashion for filtering air, in particular for filtering the combustion air to be supplied to an internal combustion engine in a motor vehicle. The filter apparatus 1 is preferably arranged in the front area of the motor vehicle and filters ambient air which is passed through the filter apparatus 1 . The filter apparatus 1 is located, for example, in the area of the radiator grille between the front headlights of the motor vehicle, in particular in the direction of travel in front of at least one heat exchanger, for example water cooler. With the aid of the filter apparatus 1 , particles in the ambient air, such as dust, can be filtered out, possibly also gaseous impurities, which are separated in the filter apparatus 1 with the aid of activated carbon filter media, for example. The filtered air can also be supplied to a vehicle passenger compartment in the motor vehicle, if necessary.

[0048] The filter apparatus 1 comprises a filter housing 2 designed as an open frame part, and a filter element 3 insertable into the filter housing 2. The filter apparatus 1 also includes a cover element 4 which, in the inserted state, rests on the upper edge side of the filter element 3 and terminates with the filter housing 2. The cover element 4 is either designed as a separate housing component placed on the upper edge side of the inserted filter element 3, but not firmly connected to the filter element 3. An alternative embodiment is also possible, in which the cover element 4 is firmly connected to the upper edge side of the filter element 3. As an alternative, the cover element 4 can also be designed in one piece with the further edge element 7. This is particularly useful if the further edge element 7 is attached to the filter medium body 5 by overmolding, which is not shown in the figure.

[0049] As can be seen in particular from the sectional views of the filter apparatus 1 according to Figs. 5 to 7, the filter element 3 comprises a filter medium body 5, which is designed as a filter bellows arranged in a cuboid shape and made from a folded filter medium. On each of the opposite front faces of the filter bellows of the filter medium body 5 is located an edge element 6 closing the filter medium body 5 in the area of this peripheral or front face in a flow-tight manner. For example, each edge element 6 is made of non-woven fabric or comprises a non-woven fabric, and can be firmly connected to the circumferential side of the filter medium body 5, for example glued or welded or injection-molded thereto. In other embodiments, the edge elements 6 can also be attached to the filter medium body 5, although this is not shown in the Figure. [0050] On the one hand, each edge element 6 on the opposite circumferential sides of the filter medium body 5 covers the respective circumferential side of the filter medium body 5 and, on the other hand, features a projecting portion 6a which projects beyond the lateral surface of the filter medium body 5. The two opposite lateral surfaces form the inflow side and the outflow side of the filter medium body, which are parallel to each other. In the embodiment example, the lateral surface of the filter medium body 5 beyond which the projection portion 6a projects is for example the inflow side.

[0051] Each projection portion 6a features a projection continuously increasing along the circumferential side of the filter medium body 5. At the lower circumferential side of the filter medium body 5, the projection portion 6a has no or only a minimum projection beyond the inflow side, whereas the projection at the opposite upper circumferential side is at its maximum. Accordingly, the edge element 6 including the associated projection portion 6a has a trapezoidal shape in top view. The projection increases continuously, wherein the projection portion 6a has the shape of a straight ramp.

[0052] In the area of the upper circumferential side of the filter medium body 5, there is a further edge element 7 which connects the two lateral edge elements 6 and also encloses the filter medium body along one circumferential side. Advantageously, this edge element 7 is firmly connected to the filter medium body 5, in particular by bonding or welding, and seals the filter medium body 5 at the relevant circumferential side in a flow-tight manner. The upper edge element 7 features approximately or exactly the same width as the maximum width of the lateral edge elements 6. Accordingly, the upper edge element 7 also has a projection towards the inflow side of the filter medium body 5. The two lateral edge elements 6 and the upper edge element 7 can be made in one piece.

[0053] On the one hand, the two lateral edge elements 6 and the upper edge element 7 serve to guide the flow of the incoming air, which is limited by the edge elements 6, 7 and directed towards the inflow side of the filter medium body 5. On the other hand, the edge elements 6 and 7 also have a guiding and supporting function for the filter element 3 inserted into the filter housing 2. In the fully inserted condition shown in Figs. 3, 5 and 6, the front edge of the projection 6a of both edge elements 6 rests against holding brackets 8 and 9, which are formed in one piece with the filter housing 2 and hold and secure the inserted filter element 3 in its inserted position. The upper edge element 7 is located on the upper side of the filter housing 2.

[0054] Each lateral edge element s is provided, in addition to the first projection portion 6a, with a second projection portion 6b projecting beyond the filter medium body 5 on the opposing lateral surface, i.e. on the outflow side. The projection of the second projection portion 6b is constant over the length of the edge element 6 and is several times smaller than the maximum projection of the first projection portion 6a beyond the inflow side of the filter medium body 5.

[0055] The second projection portion 6b is associated with a guide groove 10 in the filter housing 2 (Fig. 7), into which the second projection portion 6b projects in the assembled state of the filter element 3. The engagement of the projection portion 6b into the guide groove 10 in the filter housing 2 provides additional guidance and support for the filter element 3 in the filter housing 2.

[0056] The open filter housing 2 has a grid-shaped rear wall 11 having a plurality of flow openings between intersecting struts. In the assembled state, the filter medium body 5 rests with its outflow side directly against the rear wall 11 and supports it. The filter housing 2 is also provided with side cheeks 12, against which the edge elements 6 of the filter element 3 abut on the inside. Furthermore, the filter housing 2 features a bottom 13 on which the lower circumferential side of the filter element 3 abuts. The guide grooves 10 are provided in the bottom 13 (Fig. 7). Fastening devices 14, with which the filter housing 2 can be secured and fastened at its assembly location in the motor vehicle, are molded to opposing lateral exterior sides of the filter housing 2. The fastening devices 14 feature a hook shape and a lug shape.