Patent Publication Number: US-2020278002-A1

Title: Brake Dust Particle Filter and Disc Brake Assembly Comprising a Brake Dust Particle Filter

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application of international application No. PCT/EP2018/073600 having an international filing date of 3 Sep. 2018 and designating the United States, the international application claiming a priority date of 8 Sep. 2017 based on prior filed German patent application No. 10 2017 008 421.1, the entire contents of the aforesaid international application and the aforesaid German patent application being incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     The invention concerns a brake dust filter for a disc brake assembly with a brake disc and a brake caliper. The brake dust particle filter is configured for catching particles that are produced when braking. The invention concerns moreover a disc brake assembly with such a brake dust particle filter. 
     It is known to catch and dispose of particles that are produced by brake abrasion by means of a brake dust particle filter. Such particles are produced by friction between brake pad and brake disc of a disc brake. Such a brake dust particle filter has become known, for example, from DE 10 2012 016 835 A1. This brake dust particle filter however requires an integration in a brake caliper housing and is suitable therefore only to a limited extent as a retrofitting solution. 
     SUMMARY OF THE INVENTION 
     In contrast to this, it is the object of the present invention to provide a brake dust particle filter that is configured to be more efficient for separating particles that are produced when braking as well as suitable for retrofitting of existing vehicles. Object of the present invention is furthermore to provide a disc brake assembly with such a brake dust particle filter. 
     The brake dust particle filter according to the invention is suitable for any applications of disc brakes, mobile as well as stationary applications. In mobile applications, it can be employed, for example, in passenger cars, trucks, buses rail vehicles. Stationary applications, for example, concern shaft brakes as they are used in wind power devices. 
     The object is solved by a brake dust particle filter of the aforementioned kind that comprises:
         a ring segment-shaped housing for at least partial accommodation of the brake disc in a housing interior, wherein the housing comprises two housing sidewalls that are axially spaced apart from each other and a housing peripheral wall extending radially outwardly in circumferential direction, and wherein the housing peripheral wall is arranged or embodied between the housing sidewalls;   at least one tongue in the housing interior projecting at least in sections with at least one radial component from the housing peripheral wall inwardly;   wherein the tongue comprises a flat cross-sectional shape and at least one base surface which is facing the housing peripheral wall, a cover surface projecting into the housing interior as well as at least one side surface; and   at least one filter medium;       

     wherein the tongue supports the filter medium and is covered at least at the at least one side surface, in particular completely, with the filter medium. 
     The object is further solved by a disc brake assembly comprising the brake dust particle filter as claimed. 
     The dependent claims provide preferred further embodiments. 
     The brake dust particle filter comprises a ring segment-shaped, approximately banana-shaped and/or helmet-shaped housing. In the housing, the brake disc of a disc brake assembly is received in a mounted state. The housing comprises at least two housing sidewalls and a housing peripheral wall. The housing peripheral wall connects in the mounted state of the brake dust particle filter the two housing sidewalls directly or indirectly. In the interior of the housing, i.e., facing the brake disc, the brake dust particle filter comprises a filter medium. In order to enlarge the effective filter surface of the filter medium, a tongue that supports the filter medium is provided in the brake dust particle filter. According to the invention, the tongue extends at least in sections thereof with at least one radial component away from the housing peripheral wall in a housing interior. The tongue according to the invention has a flat cross-sectional shape and comprises a base surface which is facing the housing peripheral wall, a cover surface projecting into the housing interior as well as at least one side surface. Flat is to be understood herein as a cross-sectional shape whose wide side is much larger than its narrow side. Alternatively, such a cross-sectional shape could also be referred to as flattened or elongate. 
     The tongue is covered with the filter medium at least partially, namely at least at its side surface, preferably as much as possible, particularly preferred completely. In this way, a higher filtering effect than in the prior art is achieved. The tongue extends in this context preferably from an outer circumference to an inner circumference, i.e., radially inwardly. 
     In a preferred embodiment, the tongue can have a substantially rectangular cross section wherein a ratio of a wide side to a narrow side of the rectangular cross section is between 15 and 60, preferably between 20 and 40. Such values can be realized for a plurality of sizes of the brake dust particle filter by use of sheet metal plates in standard thicknesses for producing the at least one tongue; for example, sheet metal plates with a thickness (=narrow side of the cross section) between 0.5 and 4 mm can be employed. 
     In this context, it is not mandatory that the tongue forms a continuous body free of interruptions; instead, it can also be slotted once or multiple times, wherein generally a sufficient support function for the filter medium results even for a slotted tongue. In case of such slotted tongues, the aforementioned ratio specifications refer respectively to an outer contour of the respective tongue and not to the “partial tongues” that are produced by slotting. The tongue can be advantageously made of a mesh material, for example, a metal mesh. 
     Particularly preferred, the at least one tongue extends in such a way into the interior that its base surface in a mounted state of the brake dust particle filter extends parallel to an axis of rotation of the brake disc. 
     The tongue can be arranged or embodied at a housing wall, e.g., as one piece together with the housing wall. Preferably, the tongue is arranged or embodied at the housing peripheral wall. Alternatively or additionally, the brake dust particle filter can comprise a filter element, wherein the filter element comprises a filter element support structure on which or at which the filter medium is arranged. In this context, the filter element support structure can comprise the tongue. When providing a filter element, the filter medium is exchangeable particularly easily and environmentally friendly because only the filter element must be exchanged when the filter medium is loaded and not the complete housing. According to this embodiment, a receiving region is advantageously provided for receiving the filter element into which the filter element can be inserted. It can be held, for example, by clips or other fastening elements that appear suitable, in the receiving region. Particularly advantageously, the filter element has a curved shape, in particular a circular arc shape, which corresponds with the inner shape or the radius of the housing peripheral wall. 
     The filter medium can be fastened indirectly or directly at the tongue, at the housing wall, in particular at the housing peripheral wall, and/or at the filter element support structure. The filter medium can form a fold into which the tongue at least partially extends. In this way, the brake dust particle filter can be produced in a particularly simple way. 
     According to a further preferred embodiment, at least one additional tongue is provided that projects from at least one housing sidewall into the housing interior. Preferably, the tongue projecting from the housing peripheral wall and the tongue projecting from the housing sidewall form a continuous tongue which comprises an L-shaped or U-shaped basic form. In this way, the effective tongue surface is greatly increased which contributes to an even more improved separation performance. Moreover, in this way a configuration that saves space in radial direction is possible because a portion of the entire tongue surface can be distributed onto the tongue which is provided at the housing sidewall. 
     The tongue can comprise at least one through opening which is covered by the filter medium. In this way, the filter medium can be flowed through in the region of the tongue. The tongue can advantageously comprise also a plurality of through openings which are each covered by the filter medium. 
     In a further preferred embodiment of the invention, in the region of the tongue the filter medium is embodied in the form of a collecting pocket or catching pocket for particles wherein the catching pocket is closed in downward direction so that particles cannot fall out of the catching pocket due to the gravity acting on them. The brake dust particle filter can retain in this way large particle quantities. The shape of the collecting or catching pocket can advantageously be imparted to the filter medium by the at least one tongue which has just such a shape. Preferably, a lowest point of the pocket is pointing downwardly in the direction of gravity. 
     In a further preferred embodiment of the brake dust particle filter, the filter medium comprises at least a first filter layer with a porosity and a second filter layer with a larger porosity. The two filter layers can be embodied in the form of regions (viewed in the direction of thickness) of the filter medium so that the filter medium has a porosity gradient. Alternatively or additionally thereto, an additional filter medium can be provided on the filter medium, wherein the porosity of the additional filter medium differs preferably from the porosity of the filter medium. Due to this arrangement or configuration of different filter layers, the degree of separation of the brake dust particle filter can be matched precisely to the respective application. Advantageously, the pore size in this context decreases in radial direction from the interior to the exterior. 
     The brake dust particle filter can comprise in addition to the afore described tongue at least one additional tongue in the housing interior. In other words, the brake dust particle filter comprises preferably a plurality of tongues that are projecting inwardly in the housing interior and are preferably arranged spaced apart in circumferential direction. The tongues support the filter medium and are covered at least partially, in particular completely, by the filter medium. By the arrangement or configuration of a plurality of tongues, the filter action is further significantly increased. At least two tongues can be positioned in this context at a different angle relative to the housing peripheral wall, respectively. Angle relative to the housing peripheral wall is understood here as an angle between a tangent, placed at an imaginary contact point of the tongue at the housing peripheral wall, and the length extension of the tongue. 
     The brake dust particle filter is preferably designed such that the filtering action increases in circumferential direction of the housing. The increase is realized in this context preferably away from a bearing region of the housing, wherein the bearing region is provided for bearing against the brake caliper of the disc brake assembly. In other words, the brake dust particle filter is preferably embodied such that the filter action increases with increasing distance from the brake caliper or from the bearing region for bearing against the brake caliper. A better filter action is understood herein, for example, as the ability of separating finer particle fractions. This is realized in particular by one or a plurality of the following measures:
         The porosity of the filter medium decreases in circumferential direction of the housing. In particular, the filter medium comprises a larger porosity at a tongue than the filter medium at the next neighboring tongue which is located farther away from the bearing region of the brake dust particle filter.   The thickness of the filter medium increases in circumferential direction of the housing.   A tongue is positioned at a smaller angle relative to the housing peripheral wall than a neighboring tongue that is located farther away from the bearing region.   A tongue comprises more and/or larger through openings than a neighboring tongue which is located farther away from the bearing region of the brake dust particle filter, wherein preferably the dimensions of the through openings decrease in circumferential direction away from the bearing region.   A tongue with its free end projects less far into the interior of the housing than a neighboring tongue that is located farther away from the bearing region of the brake dust particle filter.   The surface of a tongue is smaller than the surface of a neighboring tongue that is located farther away from the bearing region of the brake dust particle filter.       

     The brake dust particle filter can comprise at least one opening for the discharge of filtered air in the housing wall, in particular in the housing peripheral wall. Preferably, the brake dust particle filter comprises a plurality of openings for the discharge of filtered air in the housing wall, in particular in the housing peripheral wall. 
     At least one opening is provided preferably in a housing end region which—viewed in circumferential direction of the housing—is embodied in the region of the brake caliper. The housing end region bridges preferably at least one radially outwardly open region of the brake caliper because, there, a high brake dust discharge occurs typically that, in addition to the brake abrasion that leaves the brake caliper in tangential direction, constitutes the greatest emission source. Preferably, the filter medium is a continuous material strip which extends across the plurality of inwardly positioned tongues as well as across the inner side of the housing peripheral wall in the housing end region. 
     In order to prevent that air is pressed by the back pressure during driving against the filtration direction through the filter medium, at least one outwardly projecting rib is arranged or embodied at the housing wall, in particular at the housing peripheral wall. Preferably, a plurality of outwardly projecting ribs are provided at the housing wall, in particular at the housing peripheral wall. The at least one outwardly projecting rib can be provided preferably in the region of the at least one opening so that the rib covers the respective opening in the traveling direction at least partially so that a dynamic pressure produced by driving does not act on the opening. Preferably, a plurality of outwardly projecting ribs are provided respectively in the region of an opening for discharge of filtered air, preferably each one of the openings is provided with an afore described rib. 
     The filter medium is preferably configured such that, even at a temperature of more than 600° C., it is stable in order to withstand the temperatures in immediate environment of a disc brake. In this context, the filter medium can comprise a metal, metal fiber nonwoven, glass, ceramic and/or a high temperature-resistant plastic material, in particular polyether ether ketone. However, the housing should comprise also advantageously a sufficient temperature resistance; for this purpose, it can be embodied of sheet metal, preferably sheet steel. In addition to the excellent temperature resistance, sheet steel has the further advantage that the housing can be obtained by a simple deformation process, for example, by deep drawing. 
     The ring segment-shaped housing covers preferably a large angle range of the brake disc in order to obtain a high filtration action. The housing extends in this context preferably about a ring segment angle of more than 45°, in particular of more than 75°, particularly preferred of more than 90°. When selecting a suitable enclosing angle, there is a conflict of objectives to be solved between the proportion of particles to be filtered and the cooling performance that can be made available to the disc brake. 
     For facilitating mounting of the housing, the housing can have a first and a second housing part. The two housing parts preferably can be arranged at least partially axially at both sides of the brake disc. Particularly preferred, the first housing part and the second housing part can be connected in a reversibly detachable way. Alternatively, the two housing parts can also be connected non-detachably, for example, welded. Advantageously, according to this embodiment, the filter medium is inserted already prior to connecting the housing parts so that at least the pre-assembly process is simplified, even though the exchange of the filter medium in service is not. In this case, it is however conceivable to exchange in the service situation the entire brake dust filter (including housing+filter medium) in order to subject it to refurbishing, for example. As an alternative to welding, it can be provided that the first housing part and the second housing part are connected to each other by a crimped connection. 
     For connecting the two housing parts, a screw connection, a clip connection, a folding mechanism and/or a pivot mechanism can be provided. 
     The housing peripheral wall can be part of the first housing part or of the second housing part so that it is connected with one of the two housing sidewalls. The housing peripheral wall can be embodied moreover at least partially of housing parts that are overlapping each other. 
     Particularly preferred, the first housing part comprises the at least one inwardly projecting tongue and the second housing part comprises at least one opening. Further preferred, all inwardly projecting tongues are provided at the first housing part and all openings at the second housing part. The separate configuration of tongue(s) and opening(s) facilitates significantly the production of the brake dust particle filter because the openings, optionally with corresponding ribs, as well as the inwardly positioned tongues can be produced by punching. 
     A housing part can be pivotable relative to an additional housing part that remains stationary. The pivot axis of such a pivot mechanism can extend parallel to an axis connecting the two housing sidewalls, in particular parallel to the axis of rotation of the brake disc. Particularly preferred, the housing part that comprises the housing peripheral wall is pivotable at least partially relative to the further housing in this case. Alternatively or additionally to this, the pivot axis can extend in the radial direction of the housing or relative to the brake disc, i.e., normal to the axis of rotation of the brake disc. In this case, a first housing sidewall is preferably pivotable relative to the further housing. 
     The afore described pivoting ability simplifies significantly an exchange of the filter medium in the service situation. 
     The object according to the invention is furthermore solved by a disc brake assembly with a brake disc, a brake caliper, and a brake dust particle filter as described above. 
     The brake dust particle filter can have a stationary position relative to the brake caliper, a wheel bearing housing and/or a splash guard. Alternatively or additionally thereto, the brake dust particle filter can be fastened to the brake caliper, to a wheel bearing housing and/or to a splash guard, wherein an attachment at the brake caliper can be advantageously provided when a so-called stationary caliper is concerned. Particularly advantageously, the brake dust particle filter can be connected to the wheel bearing housing at the same fastening points as the brake caliper. Moreover, the screws with which the brake caliper is screwed to the wheel bearing housing can comprise at least in the region of a screw head a blind bore thread so that the brake dust particle filter is connectable with the screws so that advantageously the safety-critical screw connection of the brake caliper (holder) with the wheel bearing housing is not affected (settling/pretension force change). 
     In a particularly preferred embodiment of the invention, one housing part of the brake dust particle filter can be a splash guard element, in particular splash guard plate, that, positioned inwardly, covers the brake disc at least partially. In this way, an additional splash guard plate is not required so that weight can be saved, which provides driving-dynamic advantages as a result of an arrangement in the unsprung region of a chassis. 
     In order to effect a particularly effective particle separation, the brake dust particle filter is preferably arranged so as to immediately adjoin the brake caliper. The brake dust particle filter in this context is arranged preferably downstream of the brake caliper, wherein in this context the term “downstream” relates to the rotational direction of the brake disc for an intended forward travel of the vehicle at which the disc brake assembly is provided. 
     The brake dust particle filter covers preferably at least partially an outer side of the brake caliper, particularly preferred a circumferential outer side of the brake caliper. The coverage of the brake caliper is realized preferably with the housing end region. Particularly preferred, the brake caliper is covered completely in the region of the circumferential outer side, at which often openings for cooling air supply and/or service (removal of the friction pads) are located, at least however in the region of the openings, by the housing end region of the brake dust particle filter so that no unfiltered outflow occurs in this region, but particle-laden air that exits from there first flows through the filter medium and subsequently through the opening in the housing peripheral wall into the environment. 
     In a further preferred embodiment of the disc brake assembly, the at least one inwardly projecting tongue with its free end is oriented toward the brake caliper. Preferably, a plurality, in particular all, tongues are oriented with their respective free ends toward the brake caliper. In this way, the filter efficiency can be further increased because brake dust particles that are entrained tangentially by the rotation essentially can all be caught by the shape of the tongues. 
     Further features and advantages of the invention result from the following description of several embodiments of the invention, from the claims as well as the Figures which show invention-relevant details. The features illustrated in the Figures are illustrated such that the particularities of the invention can be made visible clearly. The different features can be realized individually or several thereof combined in any combinations in variants of the invention and are therefore combinable with each other. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a side view of a disc brake assembly according to the invention with a first embodiment of the brake dust particle filter. 
         FIG. 2  shows a cross section of the brake dust particle filter according to  FIG. 1 . 
         FIG. 3  is an isometric view of the brake dust particle filter according to  FIG. 1 . 
         FIG. 4  is an isometric view of a first housing part and of a second housing part of the housing of a brake dust particle filter in a second embodiment of the disc brake assembly. 
         FIG. 5  is an isometric view of the first housing part of the housing of the brake dust particle filter of a third embodiment of the disc brake assembly with inwardly projecting tongues and a second housing part with openings and outwardly projecting ribs. 
         FIG. 6  is an isometric view of the connection of a first housing part and of a second housing part of a fourth embodiment of the disc brake assembly by a pivot mechanism and/or a folding mechanism. 
         FIG. 7  is an isometric view of the connection of the first housing part and of the second housing part by a pivot mechanism and/or a folding mechanism along a further pivot axis in a fifth embodiment of the disc brake assembly. 
         FIG. 8  is an isometric view of a brake dust particle filter according to a further embodiment with tongues at a housing peripheral wall as well as at a housing sidewall. 
     
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
       FIG. 1  shows a side view of a disc brake assembly  10  with a disc brake  12  which comprises an axis of rotation or rotary axis  13 , with a brake caliper  14  and a brake dust particle filter  16  in a first embodiment. In this context, the brake dust particle filter  16  is stationarily arranged in its position relative to the brake caliper  14  and/or attached to the brake caliper  14 . The disc brake assembly  10  comprises moreover a wheel bearing housing (not illustrated) to which the brake caliper  14  is fastened, and the brake dust particle filter  16  can be stationarily arranged in its position relative to the wheel bearing housing and/or fastened to the wheel bearing housing. Alternatively or additionally thereto, the disc brake assembly  10  can comprise a splash guard (not illustrated) in the form of a splash guard plate, and the brake dust particle filter  16  can be arranged stationarily in its position relative to the splash guard and/or can be fastened to the splash guard. 
     The brake dust particle filter  16  comprises a first housing sidewall  17  which forms a part of a ring segment-shaped housing  18 . A second housing sidewall  19  (see  FIG. 2 ) is arranged, spaced apart axially along the rotary axis  13  of the brake disc  12 , relative to the first housing sidewall  17  and also forms a part of the ring segment-shaped housing  18 , and between them the brake disc  12  is received in the housing interior  20 . 
     The brake dust particle filter  16  can be arranged downstream of the brake caliper  14 , in particular in rotation direction R of the brake disc  12  upon forward travel of a vehicle at which the disc brake assembly  10  can be arranged. 
     In  FIG. 2 , a cross section of the brake dust particle filter  16  for filtering air that is provided with brake dust is illustrated. By means of the ring segment-shaped housing  18 , the brake dust particle filter  16  can accommodate the brake disc  12  (see  FIG. 1 ) at least partially in the housing interior  20 . The ring segment-shaped housing  18  can extend about a ring segment angle α of more than 90° in this embodiment. The brake dust particle filter  16  is arranged flush at the brake caliper  14  (see  FIG. 1 ) so that, when braking, air moved by the brake disc  12  (see  FIG. 1 ) can flow from the brake caliper  14  into the brake dust particle filter  16 . 
     The housing  18  comprises a housing peripheral wall  26  which extends radially outwardly in circumferential direction of the brake dust particle filter  16 . The housing sidewalls  17  (see  FIG. 1 ),  19  are connected to each other by the housing peripheral wall  26 . 
     The brake dust particle filter  16  comprises moreover tongues  28   a ,  28   b ,  28   c ,  28   d . These tongues  28   a - 28   d  are arranged at the housing peripheral wall  26  of the brake dust particle filter  16  or embodied as in  FIG. 2 . They project in the housing interior  20  of the brake dust particle filter  16  from the housing peripheral wall  26  inwardly. In this context, they are positioned relative to the housing peripheral wall  26  at an angle β 1 , β 2 , β 3 , β 4 , respectively. At these tongues  28   a - 28   d , the air which flows into the brake dust particle filter  16  can be guided in the direction toward the housing peripheral wall  26 . The tongues  28   a - 28   d  are oriented with their respective free ends  30   a ,  30   b ,  30   c ,  30   d  toward the brake caliper  14  (see  FIG. 1 ). 
     A filter medium  32  for cleaning the air from particles is arranged at the tongues  28   a - 28   d  and covers the tongues  28   a - 28   d . The filter medium  32  extends across the side of the respective tongue  28   a - 28   d  which is facing the housing peripheral wall  26  as well as across the side which is facing away from the housing peripheral wall  26  so that the tongues  28   a - 28   d  are covered by the filter medium  32 , respectively. The filter medium is a continuous material strip which extends across all tongues  28   a - 28   d  as well as across the inner side of the housing peripheral wall  26  in the housing end region  52 . 
     In an exemplary fashion, the facing side is here identified at the tongue  28   a  by  34  and the side that is facing away by  36 . The effective filter surface is thus enlarged by the tongues  28   a - 28   d  in circumferential direction of the housing interior  20 . The filter medium  32  is moreover arranged at the sections  38   a ,  38   b ,  38   c  of the housing peripheral wall  26  between the tongues  28   a - 28   d . In this way, the filter medium  32  is connected immediately to the housing peripheral wall  26 . In particular, it is attached to the housing peripheral wall  26  and/or to the tongues  28   a - 28   d . Alternatively, it can be connected also indirectly to the wall of the housing  18  by means of further intermediate layers. The tongues  28   a - 28   d  can comprise one or a plurality of through openings (not shown) which are covered by the filter medium  32 . 
     The tongues  28   a - 28   d  form a support structure  40  for the filter medium  32 . For this purpose, the tongues  28   a - 28   d  project into folds  42   a ,  42   b ,  42   c ,  42   d  of the filter medium  32 . 
     The filter medium  32  can comprise at least a first region and a second region (not shown). The first region can be embodied between the respective tongues  28   a - 28   d  and the second region. In this context, for coarse filtration the first region can comprise a larger porosity than the second region. The filter medium in addition can also comprise a third and/or further such regions of different porosities. As an alternative thereto, the transition from a larger porosity of the filter medium to a smaller porosity in the direction of the tongue  28   a - 28   d  can also be continuously realized (gradient). 
     In a further embodiment, the brake dust particle filter comprises, in addition to the filter medium  32 , an additional filter medium (not illustrated). In this context, the filter medium  32  is arranged between the respective tongue  28   a - 28   d  and the additional filter medium. The additional filter medium comprises a larger porosity than the first filter medium. In an alternative embodiment, the brake dust particle filter  16  can comprise additional filter media with different porosity. 
     The brake dust particle filter  16  can be designed such that the filter action on the air moved in the circumferential direction by the brake disc  12  increases. For this purpose, the porosity of the filter medium  32  can decrease in circumferential direction of the housing, beginning at a bearing region  44  of the brake dust particle filter  16  provided for bearing against the brake caliper  14  (see  FIG. 1 ). Alternatively or in addition thereto, the thickness of the filter medium  32  can increase in the circumferential direction of the housing  18 , beginning at the bearing region  44  of the brake dust particle filter  16  provided for bearing against the brake caliper  14  (see  FIG. 1 ). Alternatively or additionally thereto, a tongue  28   a - 28   d  can be positioned at a smaller angle β 1 , β 2 , β 3 , β 4  relative to the housing peripheral wall  26  than a neighboring tongue  28   a - 28   d  which is located farther away from the aforementioned bearing region  44 . Alternatively or additionally thereto, the free end  30   a - 30   d  of a tongue  28   a - 28   d  can project less far radially inwardly into the interior  20  of the housing  18  than a neighboring tongue  28   a - 28   d  which is located farther away from this bearing region  44 . Alternatively or additionally thereto, the surface of at least one tongue  28   a - 28   d  that projects into the housing interior  20  can be smaller than the surface of a neighboring tongue  28   a - 28   d  which projects into the housing interior  20  and which is farther removed from this bearing region  44 . 
     The brake dust particle filter  16  comprises in its housing peripheral wall  26  openings  46   a ,  46   b  (see  FIG. 3 ). Through these openings  46   a ,  46   b  the purified air can escape to the exterior space. A part of the openings  46   a ,  46   b  is completely covered by the tongues  28   a - 28   d  covered by the filter medium  32  in the direction away from the housing interior  20  perpendicular to the circumferential direction of the brake dust particle filter  16 . Another part of the openings  46   a ,  46   b  is covered only by the filter medium  32 . In this way, it is ensured that as a whole only purified air can escape through the openings  46   a ,  46   b  to the exterior space. 
     Moreover, ribs are arranged and/or embodied outward at the housing peripheral wall  26  at the exterior side  48  and two of them are identified in an exemplary fashion by  50   a ,  50   b . The ribs  50   a ,  50   b  are arranged at the openings  46   a ,  46   b  so that the air that escapes outwardly is guided by the ribs  50   a ,  50   b  in a desired direction. The ribs  50   a ,  50   b  prevent a flow through the filter medium from the clean side to the raw side by a dynamic pressure that is generated by the travel speed. 
     The brake dust particle filter  16  comprises a housing end region  52 . The housing end region  52  can comprise at least partially the housing sidewalls  17 ,  19  and the housing peripheral wall  26 . Also, it comprises the filter medium  32  arranged at the housing peripheral wall  26 . Outwardly projecting ribs  50   a ,  50   b  and openings  46   a ,  46   b  in the housing peripheral wall  26  at the ribs  50   a ,  50   b  are also arranged and/or embodied in the housing end region  52 . The housing peripheral wall  26  extends into the housing end region  52 . The housing end region  52  covers in circumferential direction of the brake dust particle filter  16 , beginning at the radial outer side of the brake dust particle filter  16 , the brake caliper  14 , in particular a gap  56  of the brake caliper  14  (see  FIG. 4 ). The housing end region  52  comprises for this purpose a cutout which can be matched to the respective shape of the brake caliper, here a brake caliper with at least two pistons. 
       FIG. 3  shows an isometric view of the brake dust particle filter  16 . In particular, the outwardly oriented ribs  50   a ,  50   b  as well as the openings  46   a ,  46   b  can be seen. The housing  18  can be embodied as one part, i.e., one piece. 
     As illustrated in  FIG. 4 , the housing  18  of the brake dust particle filter  16  in a second embodiment of the disc brake assembly  10  can comprise a first housing part  58  and a second housing part  60 . The first housing part  58  comprises in this context the first housing sidewall  17 . The second housing part  60  comprises the second housing sidewall  19  which is axially displaced relative to the first housing sidewall  17 . Thus, the first housing sidewall  17  can be arranged axially displaced along the rotary axis  13  of the brake disc  12  relative to the brake disc  12 , and the second housing sidewall  19  can be arranged at the side of the brake disc  12  facing away from the first housing sidewall  17 . The first housing part  58  comprises openings  46   a ,  46   b . The second housing part  60 , in particular the second housing sidewall  19 , can be embodied in the form of a splash guard plate so that, in case of doubt, a separate splash guard plate of the brake disc can be omitted, which is in particular of interest for OE applications. 
     As illustrated in  FIG. 5 , in a third embodiment of the disc brake assembly  10  the first housing part  58  of the housing  18  can comprise the inwardly projecting tongues  28   a - 28   d . The second housing part  60  can comprise the openings  46   a ,  46   b  and the outwardly oriented ribs  50   a ,  50   b . The inwardly projecting tongues  28   a - 28   d  can be formed by punching out of the housing peripheral wall  62  of the first housing part  58 . The outwardly projecting ribs  50   a ,  50   b  can be embodied together with the openings  46   a ,  46   b  by punching out the ribs  50   a ,  50   b  out of the housing peripheral wall  64  of the second housing part  60 . Punching out the ribs  50   a ,  50   b  and the tongues  28   a - 28   d  in circumferential direction of the brake dust particle filter  16  in the mounted state at the respective housing peripheral wall  62 ,  64  can be realized for each pair of associated tongues  28   a - 28   d  and ribs  50   a ,  50   b  at the same location. Then by pushing on the first housing part  58  onto the second housing part  60  it can be ensured in a simple way that the openings  46   a ,  46   b  are formed at the correct locations between a respective tongue  28   a - 28   d  and rib  50   a ,  50   b , i.e., the openings  46   a ,  46   b  are positioned with precise fit above the intermediate spaces between the respective neighboring tongues  28   a - 28   d.    
     The first housing part  58  and the second housing part  60  can be connected to each other. In particular, they are connectable reversibly to each other in order to be able to perform servicing work quickly. This connection can be realized inter alia by a screw connection of the brake dust particle filter. For this purpose, a housing part  58 ,  60  can comprise a thread at its outer side and the other housing part  58 ,  60  a thread at its inner side such that one housing part  58 ,  60  can be screwed onto the other housing part  58 ,  60 . Alternatively or additionally thereto, the first housing part  58  and the second housing part  60  can be connected by a weld connection, a clip connection, and/or a crimped connection. 
     As illustrated in  FIG. 6 , in a fourth embodiment of the disc brake assembly  10 , the first housing part  58  and the second housing part  60  can be connectable and/or are connected to each other by a pivot mechanism and/or a folding mechanism in order to be able to open and close again quickly the brake dust particle filter  16 . The pivot axis  66  of the pivot mechanism can extend in this context parallel to an axis  68  which connects the two housing sidewalls  17 ,  19  or extends through them, and in this case extends additionally parallel to the axis of rotation of the brake disc. Then, the housing peripheral wall  26  can be pivoted relative to the two housing sidewalls  17 ,  19 . 
     Alternatively or additionally thereto, in a fifth embodiment of the disc brake assembly  10 , the pivot axis  66  of the pivot mechanism can extend perpendicular to the outer circumferential side  70  of the housing peripheral wall  26  of the brake dust particle filter  16  in the mounted state, as illustrated in  FIG. 7 . Then, the first housing sidewall  17  can be pivoted relative to the second housing sidewall  19  and the housing peripheral wall  26 . 
     When reviewing all Figures of the drawing, the invention in summary concerns a brake dust particle filter  16  for a disc brake assembly  10  with a brake disc  12  and a caliper  14 . In the housing interior  20  of the housing  18  of the brake dust particle filter  16 , at least one tongue  28   a - 28   d  is arranged or embodied wherein at least a section of this tongue  28   a - 28   d  projects radially inwardly. The tongue  28   a - 28   d  forms a support  40  for a filter medium  32  of the brake dust particle filter  16 . Moreover, the filter medium  32  covers the surface of the tongue  28   a - 28   d  at least partially, in particular completely. The housing  18  has the shape of a ring segment. It can be used to accommodate at least partially the brake disc  12  in the housing interior  20 . A first housing sidewall  17  and a second housing sidewall  19  as well as a housing peripheral wall  26 ,  62 ,  64  each form parts of the housing  18 . The housing sidewalls  17 ,  19  are spaced apart from each other in axial direction. The housing peripheral wall  26 ,  62 ,  64  is arranged radially outwardly in the circumferential direction of the housing  18 . The housing peripheral wall  26 ,  62 ,  64  is arranged or embodied between the first housing sidewall  17  and the second housing sidewall  19 . The brake dust particle filter  16  is configured for catching particles that are produced when braking. 
     In  FIG. 8 , finally a further embodiment of the brake dust particle filter  16  is illustrated which comprises in its housing interior  20  the afore described tongues  28   a - 28   d  spaced apart from each other in circumferential direction which project from the housing peripheral wall  26  as well as additional tongues  28   f  which project from a housing sidewall  19 . The tongues  28   a - 28   f  are embodied such that “lateral tongues”  28   f  and “circumferential tongues”  28   a - 28   d  that are located at a common circumferential angle form a continuous tongue, respectively. The resulting continuous tongue has in this context a substantially U-shaped basic form. In order to be able to better recognize the structure of the tongues  28   a - 28   f , the filter medium is not shown in the isometric view. The tongues  28   a - 28   f  have each a plurality of through openings through which the air to be filtered which is laden with brake dust can be guided while passing through the filter medium. Due to the combination of the “circumferential tongues” with the “lateral tongues”, the separation performance can be further improved. The tongues  28   a - 28   f  in the illustrated embodiment are made of a mesh material, preferably a metal mesh, which comprises the through openings already as raw material, which simplifies manufacture.