Technical Field

[0001] The invention relates to a filter element for a brake dust particulate filter having a high temperature filter medium. The invention further relates to a filter cartridge for a brake dust particulate filter having a filter element, a brake dust particulate filter having a filter cartridge, and a tool and a method for manufacturing the filter element.

Background Art

[0002] A filter element of the above-mentioned type is generally known from the background art. In particular, filter elements of this type are used on disc brakes to separate the brake dust generated by the braking process and conveyed in the flowing air.

[0003] Conventional filter elements or brake dust particulate filters feature a filter medium consisting of a filtering layer and a supporting layer. In most cases, the filter medium is flat or smooth and disposed, for use in a brake dust particulate filter, around the brake disc without contacting it. However, the flat design of the filter medium results in a severe throttling of the available flow crosssection, so that the filter medium is often bypassed due to the high dynamic pressure upstream of the filter medium. Furthermore, flat filter media have the disadvantage that no rear ventilation or no clearly defined flow cross-section can be provided on the downstream side. Because of this, air contaminated with brake dust can escape unfiltered into the environment.

[0004] In order to increase the throttle cross-section caused by the filter medium, the filtering layer is usually folded. However, common filter material is dimensionally unstable and tends to return to its original state. As a result, the filter medium must therefore be attached or welded to the supporting layer at each fold base - often manually. This represents a considerable manufacturing expense. Furthermore, the dimensional stability of the filter material cannot be guaranteed even with this production method since a return of the filter material to its original state cannot be completely prevented even with this manufacturing method. Sealing of the filter medium against a housing wall is only possible with great effort, so that conventional filter elements of this type often feature leakage flows between the housing and the filter medium. Moreover, the selection of the filter medium is additionally limited for this manufacturing method due to the material capability for connecting to the supporting layer, e.g. weldability. Because of this, filter materials with better filtration properties often cannot be used due to their unsuitability for connecting to the supporting layer.

[0005] It is an object of the invention to disclose a filter element which keeps the flow resistance low and yet is inexpensive to manufacture. It is further an object of the invention to disclose a filter cartridge having such a filter element, a brake dust particulate filter having such a filter element as well as a method and a tool for manufacturing such a filter element. Summary

[0006] This object is solved by a filter element having the features specified in claim 1 as well as a filter cartridge according to claim 1 1 , a brake dust particulate filter according to claim 16, a method according to claim 18 and a tool according to claim 21. Preferred embodiments are specified in the subclaims and the description.

[0007] According to the invention, the filter element has a high temperature filter medium. The high temperature filter medium features at least one heat-resistant filter layer. The high temperature filter medium is preferably designed for being used at ambient temperatures of the filter element of more than 300°C. It enables the use of components that heat up strongly, such as disc brakes for example.

[0008] Preferably, the high temperature filter medium is multilayered. Because of this, the high temperature filter medium can be adapted particularly flexibly with regard to the filter properties.

[0009] Furthermore, the filter element features at least one attachment portion formed on the high temperature filter medium and at least one filtration portion formed on the high temperature filter medium. In other words, the attachment portion and the filtration portion are formed on the same high temperature filter medium or in one piece.

[0010] The filtration portion is air-permeable and designed to separate solids, in particular brake dust particulates, from a flowing fluid, in particular from the air flowing around the brake disc.

[0011] According to the invention, the attachment portion has a flange section designed to connect the filter element to a housing component of the brake dust particulate filter and/or a filter cartridge. This enables the filter element to be directly disposed on a filter cartridge and/or a brake dust particulate filter.

[0012] The attachment portion, or flange section, is designed as a mechanically compacted portion of the high temperature filter medium. In other words, the high temperature filter medium is formed or, in other words, compacted in some areas and features at least two different final dimension thicknesses. In particular, the attachment portion or the flange section features a final dimension thickness different from that of the filtration portion. This increases the connectivity of the filter element in the attachment portion or in the flange section. In particular, the attachment portion thus features a higher connecting capability than the filtration portion of the high temperature filter medium.

[0013] The attachment portion or the flange section surrounds the at least one filtration portion in a frame-like manner. In other words, the attachment portion or the flange section surrounds the filtration portion without gaps. In other words, the attachment portion or the flange section does not feature any gaps that can promote leakage flows in an installed state of the filter element. A leakage flow is considered to be a fluid flow that can pass through the filter element away from the filtration portion and/or can flow past the filter element between the filter element and the attachment structure, for example the brake dust particulate filter or the filter cartridge.

[0014] In a further embodiment, the circumferential flange section can be provided with an at least partially circumferentially extending stiffening member. In embodiments, the stiffening member can fully follow a contour of the flange section. In other embodiments, a plurality of stiffening members can be distributed around the circumference of the flange section. It can further be provided that the at least one stiffening member is present on only one side of the flange section. In other embodiments, the at least one stiffening member can be present on two opposite sides of the flange section. The at least one stiffening member can be connected to the flange section by non-positive and/or positive connection techniques, for example by welding, soldering, edge-beading, riveting, Tox clinching. In embodiments, the at least one stiffening member can be a sheet metal strip. In embodiments, the stiffening member configured as a sheet metal strip can surround an outer edge of the flange section in a U-shape, which further increases the stiffening effect.

[0015] The use of the at least one stiffening member of the flange area is advantageous because the high temperature filter medium can thereby be relieved of force applications that arise during the attachment of the filter element in a housing. This is advantageous in particular, but not limited thereto, in the case of a clamping attachment of the filter element to a housing.

[0016] The filter element preferably features at least one support layer. Particularly preferably, the at least one support layer is disposed on a side of the filter element facing away from the brake disc - when the filter element is disposed on a brake disc - or on the downstream side. Because of this, the heat-resistant filter layer can be protected from external influences, for example from accidental damage due to unintentional contact with persons and/or objects from the outside.

[0017] In a preferred embodiment of the filter element, it is intended that the high temperature filter medium has at least two, in particular several, support layers. The heat-resistant filter layer is preferably disposed between two support layers. The support layer(s) protect the heat-resistant filter layer during operation from harmful influences such as flying sparks, falling rocks and/or inadmissible mechanical effects caused by air flows, which can cause damage to the sensitive heat-resistant filter layer. Furthermore, the heat-resistant filter layer can be additionally protected by the support layer(s) against accidental damage caused by unauthorized contact with persons and/or objects, e.g. during maintenance or repair.

[0018] In this case, the support layers are plastically deformable and feature only slight, preferably no, elastic recovery behavior. This enables the deformation of the high temperature filter medium, e.g. the particularly precise formation of a bulge and/or an indentation, wherein the heat- resistant filter layer is held in its deformed shape by the two support layers following the deformation. A springback of the filter element, in particular of the high temperature filter medium, can thus be prevented.

[0019] Preferably, the attachment portion forms the flange section by connecting the at least two support layers. Moreover, in this case, the filter layer of the high temperature filter medium is enclosed by the support layers by joining the support layers. In other words, after joining, the support layers form an enclosed volume filled by the filter layer. This favors the selection of materials for manufacturing the filter layer of the high temperature filter medium, since an attachment of the high temperature filter medium, or of the filter layer, can be achieved indirectly by attaching the support layers. The filter layer is thus independent of the choice of fastening devices. Basically, however, it can be said that the structure of the high temperature filter medium according to the invention with support layers laminating the heat-resistant filter layer on both sides facilitates a connection of the high temperature filter medium and, in particular by welding, it is also possible for heat-resistant filter layers which are themselves electrically non-conductive, e.g. also for glass fiber-based heat-resistant filter layers.

[0020] In a further preferred embodiment of the filter element, it is provided that the flange section features at most an insignificant, in particular no, indentation and/or bulge with respect to the filtration portion. In other words, the flange section is preferably flatly designed. This enables the filter element to be attached to the brake dust particulate filter and/or the filter cartridge particularly quickly and easily.

[0021] Alternatively or additionally, the attachment portion can have a lower air permeability than the filtration portion, in particular no air permeability at all. In other words, the attachment portion can be designed to be air-impermeable. According to DIN EN ISO 9237, the air permeability of the high temperature filter medium in the filtration portion can be between 200 - 4000 l/m ² /s, preferably between 1500 - 3000 l/m ² /s. In other words, the preferably air-impermeable attachment portion preferably surrounds an air-permeable interior space of the high temperature filter medium, or fully encloses the air-permeable filtration portion of the high temperature filter medium. This allows the air flow through the filter element to be reliably guided through the filtration portion, thus preventing leakage flows.

[0022] The filter element can feature several filtration portions. In this case, the attachment portions, which preferably completely enclose the filtration portions, can be designed to be contiguous. An attachment portion can be configured to partially enclose a further filtration portion. In other words, an attachment portion can be adjacent to a plurality of filtration portions.

[0023] In a particular multilayer embodiment, the high temperature filter medium features four or more layers. Preferably, the first and last layers are in this case support layers and the remaining layers are filter layers. Further preferably, the filter layers feature a diameter of the separable solids, in particular brake dust particulates, from the air that decreases in the through-flow direction through the high temperature filter medium. Because of this, the solids storage capacity or the dust storage capacity of the high temperature filter medium can be utilized particularly effectively. Furthermore, the degree of separation of the high temperature filter medium can be improved.

[0024] In a special embodiment of the filter element, at least one, in particular each, filter layer is designed in the shape of a medium for depth filtration. This effectively prevents the formation of a so- called filter cake. Further preferably, the at least one filter layer features or consists of metal fibers, in particular stainless steel fibers, glass fibers, mineral fibers, in particular with a basalt or alkaline earth silicate, and/or has a non-woven fabric, in particular a non-woven glass fiber. [0025] In a particular embodiment, the fibers of the filter layer feature a fiber diameter of between 2 pm and 40 pm. Because of this, a constant degree of separation of the high temperature filter medium can be achieved. When using several filter layers, it can be provided that the fiber diameter decreases in the through-flow direction. The size of the solids or particles that can be separated by the high temperature filter medium decreases as the fiber diameter decreases. Preferably, a filter layer disposed upstream in the through-flow direction, or a filter layer on the upstream side, features fiber diameters between 12 pm and 40 pm. Further preferably, a filter layer disposed downstream in the through-flow direction, or a filter layer on the downstream side, features fiber diameters between 2 pm and 8 pm.

[0026] The fiber diameter distribution is preferably uniform across the filter layer. Because of this, a uniform degree of separation across filter element is ensured.

[0027] The at least one heat-resistant filter layer, preferably the entire high temperature filter medium, can be impregnated, in particular in a water-repellent manner. This can improve the oxidation resistance and/or the water separation efficiency of the filter element as well as increase the degree of adsorption of the high temperature filter medium.

[0028] Preferably, at least one, in particular each, support layer is designed as a perforated plate, slotted screen, expanded metal or wire screen and/or one, in particular each, support layer consists of a metal or a metal alloy, in particular of steel, preferably of a stainless steel. Preferably, the support layers feature a large opening ratio, or a large ratio between the area through which flow can pass and the area through which flow cannot pass. This can reduce the flow resistance caused by the support layers and increase the through-flowable area of the heat-resistant filter layer.

[0029] Preferably, the support layers are made of a heat-resistant material and are designed for permanent use at temperatures above 300°C. Further preferably, the support layers feature a material with high strength. Because of this, it is possible to reduce the impermeable area of the support layers while maintaining the same strength.

[0030] Preferably, the support layers feature in particular a constant mesh size of 0.02 to 2.2 millimeters, particularly preferably of 0.45 to 1.4 millimeters. This is particularly advantageous with regard to the flowability of the support layers.

[0031] Further preferably, at least one, in particular each, support layer features a web width of 0.03 to 0.35 millimeters, in particular 0.1 to 0.25 millimeters. This is particularly advantageous with regard to the formability and dimensional stability of the support layers.

[0032] In a preferred embodiment, at least one, in particular each, support layer has a layer thickness of at most 0.7 millimeters, in particular at most 0.3 millimeters, particularly preferably at most 0.1 millimeters.

[0033] Further preferred is an embodiment, in which at least one, in particular each, support layer features a flexural rigidity between 1 .5 and 20 Newton millimeters, in particular from 2 to 6 Newton millimeters. [0034] The filtration portion features at least one bulge and/or indentation, preferably at least one fold for surface extension. In this context, a surface extension refers to a planar initial state of the filter layer without a bulge or an indentation. In other words, in an initial state, the projected area of the filtration portion is equal to the effective filter area of the filtration portion in the projection direction. The projection direction is preferably an axial direction and/or a main through-flow direction of the filter element. On the other hand, a bulge or indentation increases the effective filter area of the filtration portion while maintaining the same projected area. This can reduce the flow resistance of the filter element, which has a favorable effect on the dynamic pressure caused by the filter element and the filterable air volume per time.

[0035] In a preferred embodiment of the filter element, it is provided that the mounting flange is formed by positive and/or material locking connection, in particular by interlocking and/or wedging, of the support layers. Because of this, the attachment portion can be formed in a particularly simple, fast and durable manner.

[0036] In a further preferred embodiment of the filter element, the at least one bulge and/or the at least one indentation protrudes unidirectionally beyond the flange section. A unidirectional protrusion is to be understood as a one-sided protrusion of the at least one bulge and/or the at least one indentation across the flange section. Preferably, the at least one bulge and/or the at least one indentation protrudes beyond the flange section in the axial direction of the filter element. The axial direction is preferably the main through-flow direction of the filter element. Further preferably, the at least one bulge and/or the at least one indentation protrudes beyond the mounting flange in the direction of the brake disc in a condition arranged on a brake disc. Because of this, an available installation space can be effectively utilized and the flow resistance can be reduced already at the inflow side of the filter element. In other embodiments, the at least one bulge can protrude beyond the flange section in a direction away from the brake disc in a condition arranged on the brake disc.

[0037] A main through-flow direction is a theoretical global through-flow direction of the filter element. The main through-flow direction preferably results from the sum of the local flow directions through the high temperature filter medium. The main through-flow direction in the case of a planar filter element without a bulge and/or indentation can, for example, be oriented perpendicular to the filter element.

[0038] A preferred embodiment is one in which the at least one filtration portion of the filter element features a plurality of bulges and/or indentations, in particular a plurality of folds disposed adjacent to one another, preferably parallel or in alignment, in particular distributed uniformly across the filtration portion. Because of this, a particularly large surface extension can be achieved in the case of bulges with the lowest possible bulge height, or fold height, of the bulges, or folds. In the case of indentations, the particularly large surface extension is achieved analogously with the smallest possible indentation depth, or fold depth, of the indentations, or folds. In both cases, the available installation space can be used particularly effectively. [0039] Particularly preferably, a plurality, in particular all, bulges or indentations, in particular folds, feature the same bulge height or indentation depth, bulge width or indentation width and/or bulge length or indentation length. The bulge height or indentation depth refers to a bulge extension or indentation extension in or against the main through-flow direction of the filtration portion. The bulge width or indentation width and the bulge length or indentation length are bulge extensions or indentation extensions, respectively, in the area of the filtration portion projected in the main through-flow direction. In other words, the bulge height or indentation depth is determinable perpendicular to the bulge width or indentation width and the bulge length or indentation length. A high degree of equality of the bulges or indentations favors fast and easy fabrication of the filter element.

[0040] In a preferred further development of the filter element, the attachment portion is designed by mechanical compression, in particular by pressing, of the support layers. Mechanical compression is a particularly fast, cost-effective and reliable method of forming the attachment portion. [0041] Further preferred is an embodiment of the filter element in which the flange section is formed mainly in a plane orthogonal to the main through-flow direction of the filtration portion, or is formed mainly curved to a curvature axis orthogonal to the main through-flow direction of the filtration portion. In other words, the filter element can be curved in the plane projected in the main through-flow direction or around a curvature axis parallel to this plane. This is of particular advantage to enable the filter element to be designed as an axial filter element and/or as a radial filter element.

[0042] The axial filter element is a filter element designed for being arranged in an axial direction of a disc brake or a brake disc. The axial filter element is substantially flat and designed as a circular ring portion. In other words, the axial filter element is based on the axial brake disc contour.

[0043] The radial filter element is a filter element designed for being arranged in a radial direction of the disc brake or the brake disc. The radial filter element is substantially curved in space and designed as a rectangle. In other words, the radial filter element is based on the radial brake disc circumference.

[0044] In a preferred further development of the filter element, at least one partial portion of the flange section is angled from the plane orthogonal to the main through-flow direction towards the main through-flow direction of the filtration portion. In other words, a partial portion of the flange section or the attachment portion is angled with respect to the plane projected in the main through-flow direction of the filtration portion. Preferably, the entire flange section is inclined from the orthogonal plane towards the main through-flow direction. Particularly preferably, the at least one partial portion, in particular the entire flange section, is designed parallel to the main through-flow direction. Preferably, the attachment portion or the flange section extends parallel to the main through-flow direction of the filtration portion. Because of this, the filter element can be disposed or attached particularly flexibly on a cartridge body or a brake dust particulate filter. [0045] The task is further solved according to the invention by a filter cartridge for a brake dust particulate filter with the filter element and a cartridge body. Preferably, the filter element is permanently attached to the cartridge body by means of the attachment portion.

[0046] The cartridge body is designed to accommodate a brake disc, at least partially. The cartridge body can be designed to encompass around the brake disc on two or three sides. In other words, the cartridge body can be designed as an L-shape or as a C- or U-shape in a cross-section that encompasses the brake disc. Because of this, the cartridge body can reduce flow around the filter element.

[0047] The cartridge body features at least one filter element recess. The filter element recess is designed for the arrangement of the filter element. The filter element recess preferably features an edge surrounding the filter element recess, which is designed for arranging, in particular attaching, the filter element. This simplifies the arrangement or attachment of the filter element to the filter cartridge. [0048] In combination of the cartridge body with a previously described flange section - having at least one partial portion inclined from the plane orthogonal to the main through-flow direction towards the main through-flow direction of the filtration portion - it can be provided that the filter element is attached to an adjacent lateral surface of the cartridge body or the brake dust particulate filter. In this embodiment, the filtration portion of the filter element can overlap the filter element recess of the cartridge body, so that an effective flow cross-section, which is decisive for throttling the air flow to be filtered, does not coincide with a flow cross-section of the filter element recess. In this case, the effective flow cross-section can be formed upstream or downstream of the filter element recess of the cartridge body in the main through-flow direction of the filter element. Thus, the flow cross-section provided by the filter element recess is not additionally restricted by the effective flow cross-section of the filter element. This can reduce the flow resistance through the filter element or a higher volume of air to be filtered per time.

[0049] Preferably, the cartridge body features two or more filter element recesses. This enables the particularly simple arrangement of further filter elements on the filter cartridge.

[0050] The cartridge body is preferably made of a thermally resistant material, in particular metal. However, it can also be made of a plastic material, in particular a thermoplastic, which offers advantages when manufactured by injection molding. A cartridge body made of plastic material can certainly be used in individual cases depending on the expected thermal stress in the brake environment. In the case of a cartridge body made of plastic material, the filter element can preferably be connected to the cartridge body by welding the attachment portion of the filter element to an edge surrounding the filter element recess of the cartridge body. Ultrasonic welding is particularly suitable as a welding method since this is both process-reliable and can be implemented with short cycle times.

[0051] Preferably, the cartridge body is made in one piece. Further preferably, the cartridge body is made from only one blank, in particular by sheet-metal forming. This enables the cartridge body to be manufactured particularly quickly and inexpensively without tools. [0052] The attachment portion of the filter element is attached in an air-impermeable manner to the cartridge body, preferably to an edge of one of the filter element recesses. Thus, leakage flow of the filter element via the attachment portion or between the attachment portion and the cartridge body can be effectively prevented.

[0053] The filtration portion of the filter element closes or covers the filter element recess. Preferably, the filtration portion completely closes or covers the filter element recess. In other words, the filtration portion comprises at least the area of the filter element recess. Because of this, an available filter element recess can be used effectively with respect to the lowest flow resistance.

[0054] In a preferred embodiment of the filter cartridge, the cartridge body forms a circular ring segment in a plane parallel to the receivable brake disc. Because of this, the filter cartridge can be arranged on the disc brake in a particularly space-saving manner.

[0055] In a preferred embodiment of the filter cartridge, the filter element is attached to the cartridge body by positive locking, in particular by means of edge-beading, and/or by material locking, in particular by means of welding. The exemplary fastening devices described above are advantageous in this respect with regard to a particularly high level of process automation.

[0056] In a particularly preferred embodiment of the filter cartridge, the filter cartridge features at least two filter elements and the at least two filter elements are attached to the cartridge body, in particular facing different sides of the brake disc. In other words, the filter elements are preferably formed on different lateral surfaces of the cartridge body. Because of this, the air flowing out of the brake disc and contaminated with brake dust can be filtered in several downstream directions of the brake disc. In addition, the flow resistance of the entire filter cartridge and/or the brake dust particulate filter is improved.

[0057] A preferred further development of the filter cartridge provides that the at least two filter elements are disposed opposite each other and/or at a right angle to each other on the cartridge body. In other words, in this further development, the filter elements are disposed axially opposite one another on the brake disc. Because of this, it is possible to provide a particularly large filtration portion.

[0058] The object is also solved by a brake dust particulate filter for a means of transport featuring a brake disc, in particular for a wheel-driven vehicle, especially preferably for a motor vehicle, having a filter housing and the filter element.

[0059] The filter element is preferably designed to filter brake dust from the air flowing around the brake disc and is disposed in the immediate surrounding area of the brake disc.

[0060] The filter housing is designed to cover the filter element. This effectively prevents unwanted contact with the interior space of the brake dust particulate filter by objects and/or persons. Further advantageously, the brake dust particulate filter can be effectively protected from impurities and/or liquids, in particular splashing water. [0061] The filter element can be directly disposed on the brake dust particulate filter. Because of this, further components can be dispensed with, which can have a favorable effect on manufacturing costs.

[0062] In a preferred embodiment, the brake dust particulate filter features a filter cartridge, wherein the filter cartridge features the filter element. In other words, the filter element is directly disposed on the filter cartridge. The filter cartridge can be detachably or replaceably disposed on the brake dust particulate filter. This can reduce the maintenance and repair effort, since only a part of the brake dust particulate filter needs to be replaced after saturation of the filter element.

[0063] The object is further solved by a method for manufacturing the filter element from a filter blank with the method steps:

[0064] a) Prefabrication of the filter blank, in particular designed as a high temperature filter medium, by forming bulges and/or indentations, in particular by introducing folds by means of pleating, in a single layer arrangement, in particular with at least one filter layer and at least two support layers;

[0065] b) Fixing the filter blank; and

[0066] c) Mechanical compacting, in particular pressing, of the filter blank in certain areas to form the attachment portion surrounding the filtration portion in a frame-like manner.

[0067] The filter blank is preferably designed as a reshaped high temperature filter medium. Further preferably, the high temperature filter medium is a multilayer filter medium with at least one bulge and/or indentation for surface extension. Preferably, the reshaped high temperature filter medium features a single-layer composite having at least one filter layer and at least two support layers. In the case of a high temperature filter medium featuring at least two support layers, the filter layer is particularly preferably disposed between the support layers.

[0068] A preferred further development of the process provides that the mechanical compacting is carried out by pressing the filter blank, wherein the pressing is carried out in particular with a pressing force between 300 kilonewtons and 1000 kilonewtons, preferably between 600 kilonewtons and 800 kilonewtons.

[0069] In a preferred embodiment of the method, the filter element is trimmed along an outer edge of the mechanically compacted, in particular pressed, attachment portion, in particular during process step c) or immediately following process step c). This enables the filter element to be trimmed using the same stroke means as for mechanical compacting. Because of this, the filter element can be manufactured in a process-favorable manner in one stroke movement.

[0070] Furthermore, the object is solved by a tool for manufacturing the filter element from the filter blank. The tool can be part of a, in particular automated, production line. Preferably, the tool is designed for direct subsequent storage on a reshaping means for forming the at least one bulge and/or the at least one indentation, for example a pleating unit. [0071] The tool features two tool jaws movable relative to each other and designed for mechanical compacting, in particular pressing, of the filter blank and for forming the attachment portion. For this purpose, the tool jaws can feature at least one press block and/or at least one pressing punch, which are preferably movable in the direction of the main through-flow direction of the filtration portion. The press block and/or the pressing punch further preferably feature a pressing surface which corresponds to the surface of the complete attachment portion of the finished filter element. Because of this, the attachment portion can be formed in a process-efficient manner in a single pressing operation. [0072] The tool jaws feature a filter medium locator for positioning and holding the filter blank within the tool.

[0073] The filter medium locator is formed at least partially complementary to the at least one bulge and/or the at least one indentation of the filter element. In other words, the filter medium locator can feature recesses and/or projections, in particular combs in the case of folds, which are formed complementarily to the at least one bulge and/or the at least one indentation and which engage in the bulge and/or in the indentation during the mechanical compacting, in particular the pressing, of the attachment portion. Because of this, the filter blank can be positioned and fixed before and during mechanical compacting, in particular pressing, so that more precise mechanical compacting, in particular pressing, of the attachment portion can take place. Furthermore, the filter medium locator serves a dimensionally accurate production of the filter element since the intended deformation can be limited to the attachment portion and the deformation is substantially prevented in the area of the bulges or indentations.

[0074] The filter medium locator can feature a gap width, in particular in the direction of the bulge height or indentation depth, between the filter medium locator of one tool jaw and the filter medium locator of the other tool jaw, which is not completely filled by the accommodated filter blank. In other words, the filter blank is loosely disposed within the filter medium locator. The gap width can be adapted to different dimensions of the filter blank. This can prevent deformation of the bulges and/or indentations of the filter blank during mechanical compacting, in particular pressing, by the tool jaws.

[0075] In a preferred further development, the gap width can be less than the dimension of the filter blank in some areas. In other words, the filter blank is clamped by the filter medium locator in some areas. For example, a projection of the filter medium locator of one tool jaw can engage in the bulge and/or the indentation, in particular a comb in the fold base, and press it against the filter medium locator of the other tool jaw. In this case, the filter blank is clamped within the filter medium locator. Because of this, the filter blank can be fixed particularly securely.

[0076] Further preferably, the gap width can be designed to form the bulge height or indentation depth, bulge width or indentation width, and/or bulge length or indentation length of the at least one bulge and/or the at least one indentation. In this case, the filter medium locator is designed as a press mold for the filtration portion of the filter element. The at least one bulge and/or the at least one indentation of the filter element can thus be adjusted in a particularly simple manner and inaccuracies of the forming operation for forming the at least one bulge and/or the at least one indentation can be compensated.

[0077] The filter medium locator preferably features a fixation surface comprising the recesses and/or projections, which corresponds to the surface of the filtration portion projected in the main through-flow direction. Because of this, the entire filtration portion can be fixed using the filter medium locator and protected from deformation.

[0078] A preferred embodiment of the tool provides that the press block and/or the pressing punch of at least one tool jaw is designed to be movable along the stroke axis of the tool relative to the filter medium locator of the same tool jaw, in particular to extend and/or shorten the stroke. Because of this, mechanical compacting, in particular pressing, or fixing can be realized upstream and/or downstream depending on the manufacturing process.

[0079] Preferably, it can be provided that at least one, in particular each, tool jaw has a cutting die and/or a cutting punch designed to cut through the filter element. The at least one cutting die and/or the at least one cutting punch is preferably formed along the stroke axis of the tool relative to the pressing punch and/or the filter medium locator. Because of this, the filter element can be cut through immediately after the attachment portion has been mechanically compacted, in particular pressed.

[0080] The at least one cutting die and/or the at least one cutting punch are designed in particular to cut through the filter element along an outer edge of the attachment portion. Because of this, the at least one bulge and/or the at least one indentation can be fixed and retained, the attachment portion can be mechanically compacted, in particular pressed, and the filter element can be cut to size by means of a stroke movement.

Brief Description of Drawings

[0081] Other features and advantages of the invention will become apparent from the following detailed description of embodiment examples of the invention, from the patent claims as well as with reference to the figures of the drawing which show details according to the invention. The aforementioned features and those described in still further detail can be implemented individually or in any number of appropriate combinations in variants of the invention. The features shown in the drawing are presented in such a way that the special features according to the invention can be made clearly visible.

[0082] In the drawing, the following is shown:

Fig. 1 a brake dust particulate filter according to the invention having a filter cartridge and two filter elements disposed on a disc brake;

Fig. 2 the brake dust particulate filter from Fig. 1 in a sectional view along the cut edge

B-B in Fig. 1 ;

Fig. 3 the filter cartridge of the brake dust particulate filter from Figs. 1 and 2 in a state detached from the disc brake; Fig. 4 a perspective representation of the filter element from Fig. 3;

Fig. 5 a perspective representation of a further embodiment of a filter cartridge, comprising a filter element with an angular attachment portion;

Fig. 6 the filter cartridge from Fig. 5 in a sectional view;

Fig. 7 the filter element from Figs. 5 and 6 in a perspective representation detached from the filter cartridge;

Fig. 8 another embodiment of a filter cartridge featuring a filter element with a recess;

Fig. 9 top view of the filter element featuring the recess from Fig. 8;

Fig. 10 The filter element featuring the recess from Figs. 8 and 9 in a perspective representation;

Fig. 1 1 a schematic arrangement of a single-layer arrangement for manufacturing a filter blank designed as a high temperature filter medium, featuring a heat-resistant filter layer disposed between two support layers;

Fig. 12 a schematic representation of an exemplary forming process of the single-layer arrangement of Fig. 1 1 to form a filter blank designed as a high temperature filter medium;

Fig. 13 a schematic representation of a filter blank designed as a high temperature filter medium;

Fig. 14 a schematic representation of a filter element having a provided attachment portion;

Fig. 15 a sectional view of an embodiment of a tool according to the invention for manufacturing a filter element from a filter blank with two tool jaws and a filter element fixation in an opened state; and

Fig. 16 the tool from Fig. 15 in a closed state.

Description of Embodiments

[0083] Fig. 1 shows a disc brake 10 with a brake disc 12, a brake caliper 14 and a brake dust particulate filter 16. According to the embodiment shown, the brake dust particulate filter 16 is disposed downstream of the brake caliper 14 in a direction of rotation 18 of the brake disc 12. Such an arrangement is particularly effective when the direction of rotation 18 of the disc brake 10 is a main direction of rotation, or a predominantly used direction of rotation. For example, the direction of rotation 18 of a wheel of a motor vehicle disposed on the brake disc 12 in forward motion. Brake dust (not shown) generated during the braking process is thereby mainly carried along in the direction of rotation 18 across a certain angular range and subsequently separated. In the case of a disc brake 10 not featuring a main direction of rotation, it can be provided that a brake dust particulate filter 16 is disposed upstream of the brake caliper 14 (not shown) and that a further brake dust particulate filter 16 is disposed downstream.

[0084] According to the embodiment, the brake dust particulate filter 16 extends in the direction of rotation 18 across an angular range of 100°±45°, in particular ±30°, preferably ±15°. This allows effective separation of brake dust via the brake dust particulate filter 16 while at the same time providing good air cooling of the brake disc 12. In other embodiments, however, the angular extent can extend beyond this and range, for example, between 150° and 280°.

[0085] The brake dust particulate filter 16 surrounds the brake disc 12 at the radially outer edge of the brake disc 12. This can prevent a great part of air contaminated with brake dust from flowing unfiltered around the brake dust particulate filter 16 (see also Fig. 2).

[0086] Fig. 2 shows the disc brake 10 of Fig. 1 in a view of the cut edge B-B of Fig. 1. The brake dust particulate filter 16 features a filter holder 20, a filter housing 22, and a filter cartridge 24. The filter cartridge 24 features a cartridge body 26 and two filter elements 28.

[0087] The cartridge body 26 features a substantially L-shaped cross-section and is configured to be disposable on, or attachable to, the filter holder 20. Preferably, the cartridge body 26 is welded, glued and/or screwed to the filter holder 20. In other words, the cartridge body 26 together with the filter holder 20 forms a U-shaped or a C-shaped cross-section according to the embodiment.

[0088] Alternatively or additionally, it can be provided that the cartridge body 26 forms a substantially U-shaped or C-shaped cross-section. Because of this, filter elements 28 can be disposed on all sides of the cartridge body 26 facing the brake disc 12.

[0089] The filter holder 20 serves to dispose the brake dust particulate filter 16 on the disc brake 10. Preferably, the brake dust particulate filter 16 is detachably disposed on the disc brake 10 to allow better maintenance and repair.

[0090] According to the embodiment, a filter element 28 is designed as a radial filter element 30. The radial filter element 30 is disposed in the radial direction of the brake disc 12 directly on the filter cartridge 24 or indirectly on the brake dust particulate filter 16. The radial filter element 30 features a radial main through-flow direction 32 with respect to the brake disc 12.

[0091] According to the embodiment shown, the other filter element 28 is designed as an axial filter element 34. The axial filter element 34 is disposed in the axial direction of the brake disc 12 directly on the filter cartridge 24 or indirectly on the brake dust particulate filter 16. The axial filter element 34 features an axial main through-flow direction 36 with respect to the brake disc 12.

[0092] A main through-flow direction 32, 36 refers to a global through-flow direction relative to the filter element 28, although each filter element 28 can feature a plurality of local, different through- flow directions.

[0093] According to the embodiment shown, the filter elements 28 are disposed in an L-shape. The filter elements 28 are fluid-tightly attached to the cartridge body 26, for example welded, glued, clamped and/or soldered. Because of this, flow around the filter elements 28 is prevented and the degree of separation of the brake dust particulate filter 16 is improved.

[0094] In the event of a braking process or an active braking of the brake disc 12 by the brake pads mounted in the brake caliper 14 (see Fig. 1 ), brake dust (not shown) is generated as a result of the friction between the brake caliper 14 and the brake disc 12 and is entrained in an air flow (not shown) forced by the rotational motion of the brake disc 12. The air flow is guided by the rotational motion of the brake disc 12 along an exemplary flow path 38 through the filter element 28 - in this case, the axial filter element 34 - so that the entrained brake dust is separated at the filter element 28. The purified air flow is then guided through the filter housing 22 of the brake dust particulate filter 16 into the environment.

[0095] Fig. 3 shows the filter cartridge 24 in a rear view of the axial filter element 34 detached from the brake dust particulate filter 16 (see Figs. 1 and 2).

[0096] According to the embodiment, the cartridge body 26 is substantially shaped as a circular ring portion. On the one hand, the cartridge body 26 can feature a brake caliper end section 40 adapted to the brake caliper 14. This allows the filter cartridge 24 or the brake dust particulate filter 16 (see Figs. 1 and 2) to be disposed on the brake caliper 14 with as few gaps as possible so that leakage flows between the brake caliper 14 and the brake dust particulate filter 16 are reduced. On the other hand, the cartridge body 26 can feature a brake disc end section 42. The brake disc end section 42 preferably features end sections (not visible) projecting axially towards the brake disc 12 (see Figs. 1 and 2) and which are as close as possible to the brake disc 12 without contacting it. Because of this, the lowest possible leakage flow through the brake disc end section 42 can be achieved so that a higher proportion of air flow passes through the filter elements 28.

[0097] The cartridge body 26 features a filter element recess 44 for arranging the filter element 28 - in this case, the axial filter element 34. In other words, the filter element 28 covers the filter element recess 44 of the cartridge body 26. According to an embodiment, the filter element 28 has a filtration portion 46 that substantially, in particular completely, covers the filter element recess 44 of the cartridge body 26. The filtration portion 46 is indicated by a dotted line according to Fig. 3. The filtration portion 46 is air-permeable, but is designed to separate solids, or brake dust particulates, from the air.

[0098] According to the embodiment shown, the filtration portion 46 is designed orthogonally to the main through-flow direction 36 of the filter element 28. The main through-flow direction 36 is directed out of the image plane in the embodiment shown in the figure.

[0099] The filter element 28 is fluid-tightly attached to the cartridge body 26. According to the embodiment, the filter element 28 features an attachment portion 48 for this purpose, which is attached to an edge 50 of the filter element recess 44.

[0100] The attachment portion 48 and the filtration portion 46 are preferably formed on the filter element 28. In other words, the filtration portion 46 and the attachment portion 48 feature the same materials or the same material composite.

[0101] Fig. 4 shows the filter element 28 from Fig. 3, which is designed as an axial filter element 34, in an individual representation. The basic shape of the filter element 28 features a circular ring portion (see also Fig. 3). According to the embodiment of the filter element 28 shown, the attachment portion 48 surrounds the filtration portion 46. The attachment portion is preferably provided with a lower air permeability or even air impermeability by thermal, mechanical and/or chemical processing. Particularly preferably, the attachment portion is made impermeable to air by mechanical compacting. In other words, air can pass through the filter element 28 - in a state of the filter element 28 disposed on the cartridge body 26 (see Fig. 3) - only through the filtration portion 46.

[0102] According to the embodiment, the attachment portion 48 forms a plane. This allows a particularly simple and at the same time reliably fluid-tight arrangement on the cartridge body 26.

[0103] The filtration portion 46 features several - here exactly 25 - bulges 52 - here in the shape of folds 54 - (for reasons of clarity, only three bulges 52 or folds 54 are provided with a reference numeral). The bulges 52 feature a bulge height 56 in the main through-flow direction 36, a bulge length 58 and a bulge width 60. According to the embodiment, the bulge length 58 and the bulge width 60 cover a plane orthogonal to the main through-flow direction 36.

[0104] The bulges 52 are disposed adjacent one another along the filter element 28, which extends as a circular ring portion. The bulges 42 can be aligned at a common fold center (not shown). The bulges 52 can be disposed in the direction of the bulge lengths 58 in a fan-like manner. Accordingly, in accordance with the embodiment shown, the bulge width 60 can increase with increasing radial distance from the fold center. Preferably, in a condition of the filter element 28 disposed on a disc brake 10, the fold center is disposed at a center of rotation (not shown) of the brake disc 12 (see Figs. 1 and 2). However, in an embodiment not shown, the bulges 42 in the shape of filter pleats can run parallel to each other.

[0105] According to the embodiment shown, the bulges 52 are designed unidirectionally with respect to the attachment portion 48. In other words, the bulges 52 protrude only in a direction with the bulge height 56 above the attachment portion 48. According to the embodiment, the bulges 52 protrude beyond the attachment portion 48 in a direction opposite to the main through-flow direction 36. In a state of the filter element 28 disposed on a disc brake 10, the bulges 52 thus project in the direction of the brake disc 12. Because of this, the maximum cross-section through which flow can pass in the filtration portion 46 on the upstream side of the filter element 28 can be increased in a flow-favorable manner.

[0106] The previously described design of the bulges 52 can be applied in an analogous manner to the radial filter element 30 (see Fig. 2).

[0107] Fig. 5 shows another embodiment of a filter cartridge 24 in a perspective view. The filter cartridge 24 features exactly one filter element 28 designed as an axial filter element 34.

[0108] In a state of the filter element 28 disposed on a disc brake 10 (see Figs. 1 and 2), the filter element 28 is attached to a side facing the brake disc 12, or an interior side of the filter cartridge 24.

[0109] The filter element 28 features a plurality of bulges 52 provided on the filter element 28 in a fan-like manner (for clarity, only three bulges 52 are provided with a reference numeral).

[0110] Fig. 6 shows a sectional view of the filter cartridge 24 of Fig. 5. The filter element 28, which is designed as an axial filter element 34, features a main through-flow direction 36 directed out of an interior space 62 of the cartridge body 26 or of the brake dust particulate filter 16 (see Figs. 1 and 2) into the environment 64. The filtration portion 46 features a plane 66 orthogonal to the main through- flow direction 36. According to the embodiment, the attachment portion 48 features a flange section 68 formed obliquely - in this case substantially perpendicular to the orthogonal plane 66. In other words, according to the embodiment shown, the attachment portion 48 is designed substantially parallel to the main through-flow direction 36. Because of this, the axial filter element 34 - as shown - can be attached to a lateral surface of the cartridge body 26 adjacent a lateral surface forming the filter element recess 44 by means of the flange section 68. Because of this, the filtration portion 46 can clearly overlap the filter element recess 44 in the orthogonal plane 66 so that the effective flow cross-section through the filter element 28 increases. The strength of the cartridge body 26 is not affected by this, if the dimension of the filter element recess 44 is held constant. In other words, the effective flow cross-section of the filtration portion 46 of the filter element 28 is displaced upstream of the filter recess 44 in the main through-flow direction 36, resulting in lower flow resistance.

[0111] Furthermore, in a further development, it can be provided that the filter element recess 44 of the cartridge body 26 is dimensioned to be larger while the dimensions of the cartridge body 26 remain the same. This is advantageous in cases where only a small bulge height 56 is possible, but a reduction in flow resistance shall be achieved in any case.

[0112] According to the embodiment shown, the filtration portion 46 completely covers the filter element recess 44 of the filter element 28.

[0113] Fig. 7 shows the filter element 28 from Figs. 5 and 6 in a representation detached from the filter cartridge 24 (see Figs. 5 and 6). The flange section 68 - angled according to the embodiment - of the attachment portion 48 is designed circumferentially and parallel to the main through-flow direction 36.

[0114] Fig. 8 shows another embodiment of a filter cartridge 24 having two filter elements 28. One of the filter elements 28 is designed as an axial filter element 34 and the other filter element 28 as a radial filter element 30.

[0115] According to embodiment, both the axial filter element 34 and the radial filter element 30 are attached - in a state of the filter cartridge 24 disposed on the disc brake 10 (see Figs. 1 and 2) - to a side of the cartridge body 26 facing the brake disc 12 (see Fig. 1 ).

[0116] The attachment portions 48 (here concealed by the cartridge body 26) of the filter elements 28 can be disposed in an overlapping manner. In other words, the flange section 68 (here concealed by the cartridge body 26) can be disposed in layers and attached together to the cartridge body 26, for example, soldered, welded, and/or glued.

[0117] The cartridge body 26 and the radial filter element 30 feature a recess 70. In other words, the radial filter element 30 is designed to fit the cartridge body 26. Because of this, the cartridge body 26 can be adapted in a particularly space-saving manner to the prevailing installation conditions on a disc brake 10. [0118] For the sake of completeness, it should be noted that the cartridge body 26 and the radial filter element 30 can also feature a bulge. The described recess 70 and/or bulge can of course also be formed in an axial filter element 34.

[0119] Fig. 9 shows the radial filter element 30 in a top view and Fig. 10 shows the radial filter element 30 in a perspective view. The radial filter element 30 forms several - here exactly 25 - bulges 52 - here folds 54. The main through-flow direction 32 of the radial filter element 30 is directed opposite to the formation direction of the folds 54 from a side facing the disc brake 10 (see Figs. 1 and 2) in the disposed state of the filter element 28 to a side of the filter element 28 facing away from the disc brake 10. In other words, the main through-flow direction 32 is directed radially outward from a brake disc 12 (see Figs. 1 and 2). Because of this, the flow cross-section throttled by the filter element 28 can be increased.

[0120] The radial filter element 30 features a curvature axis 72. According to the embodiment shown, the curvature axis 72 runs parallel to an extension direction of the folds 54 featuring the bulge length 58. The curvature axis 72 runs orthogonal to the main through-flow direction 32. In the embodiment shown, the filter element 28 is designed to be curved around the curvature axis 72. The filter element 28 can have a constant curvature or the attachment portion 48 can feature a constant distance from the curvature axis 72 at any point. In other words, the filter element 28 can be circularly curved. Alternatively, it can be provided that the filter element 28 is unevenly curved or the attachment portion 48 features different distances from the curvature axis 72. In this case, the filter element 28 can be elliptically curved, for example.

[0121] According to the embodiment, the curved attachment portion 48 forms a curved flange section 68. Because of this, the filter element 28 can be attached to the attachment cartridge 24 (see Fig. 8) in a particularly simple and fluid-tight manner.

[0122] According to the embodiment, the bulge height 56 of the bulges 52 is designed to be constant inside a bulge 52 and across the bulges 52. According to the embodiment shown, the bulge width 60 is designed to be constant inside a bulge 52 and across the bulges 52. According to the embodiment shown, the bulge length 58 varies as it follows the recess 70 of the filter element 28. The bulges 52 or the folds 54 of the radial filter element 32 are formed parallel to each other on the filter element 28.

[0123] The features described herein by way of example for a radial filter element 32 with respect to a curvature of the filter element and bulges of variable length are expressly transferable to other filter elements according to the invention independently of further features.

[0124] The attachment portion 48 features a constant width and follows the outer contour of the filter element 28. According to the embodiment, the filter element 28 is made of a unique single layer arrangement 74 (see Fig. 1 1 ). In other words, the attachment portion 48 and the filtration portion 46 are formed on the same single layer arrangement 74. As a result, the filtration portion 46 and the attachment portion 48 are made in one piece. [0125] Fig. 1 1 shows a schematic representation of a single layer arrangement 74 for a high temperature filter medium 76 to be manufactured (see Fig 13). According to the embodiment, the single layer arrangement 74 features a heat-resistant filter layer 78 and two support layers 80. The heat- resistant filter layer 78 is disposed between the support layers 80. In other words, the support layers 80 are disposed on both sides of the heat-resistant filter layer 78.

[0126] The heat-resistant filter layer 78 is designed for depth filtration. Deposited particles are stored in the filter layer 78, which effectively prevents the formation of a so-called filter cake.

[0127] The heat-resistant filter layer 78 can, for example, comprise or consist of metal fibers, in particular stainless steel fibers, glass fibers, mineral fibers, in particular with a basalt or alkaline earth silicate, and/or be constructed as a non-woven fabric, in particular as a glass fiber non-woven fabric and/or as a metal fiber non-woven fabric.

[0128] The support layers 80 feature a grid-like design. This keeps the flow resistance of the support layers 80 as low as possible. Preferably, the support layers 80 are made of metal. Metal is particularly strong and can be used at high temperatures. This ensures dimensional stability in all areas of application of the high temperature filter medium 76.

[0129] The heat-resistant filter layer 78 and/or the support layers 80 can, for example, be unrolled from one and/or more layer supports (not shown), e.g. rollers. The heat-resistant filter layer 78 and/or the support layers 80 are preferably guided using one or more guides, in particular roller guides. [0130] In the schematic representation, the heat-resistant filter layer 78 and the two support layers 80 are disposed loosely against each other or are loosely placed on top of each other.

[0131] Fig. 12 shows the single layer arrangement 74 of Fig. 1 1 during an exemplary forming operation for manufacturing the high temperature filter medium 76 (see Fig. 13). According to the embodiment shown, the single-layer arrangement 74 is guided by a folding device 82. By means of two folding knives 84 movable transversely to the filter layer 78 and the supporting layers 80, bulges 52 - or folds 54 in this case - are designed on the single-layer arrangement 74. In an analogous manner, indentations (not shown) can be designed in the single-layer arrangement.

[0132] The forming operation causes the filter layer 78 - here - to be deformed together with the two support layers 80. While the solitary filter layer 78 would largely return to its original shape following deformation after completion of the forming operation without additional fastening devices, the filter layer 78 remains in the deformed state when disposed between the support layers 80. This allows for the dimensionally stable formation of the bulges 52 or folds 54, and at the same time provides a dimensionally stable high temperature filter medium 76.

[0133] Fig. 13 shows a schematic representation of the high temperature filter medium 76 after completion of the forming process. The filter layer 78 and the two support layers 80 are in a pleated or folded arrangement with each other. Preferably, the degree of the bulges 52 or, in this case, the formation of the folds 54 is selected in such a way that the support layers 80 are disposed permanently attached to the filter layer 78 as a result of the forming process by wedging the individual layers together. [0134] Fig. 14 shows in a schematic representation the filter element 28 after completion of the mechanical compacting, for example the mechanical compression, in particular the pressing, to form the attachment portion 48 on the filter element 28.

[0135] During mechanical compacting, two press jaws (not shown) are preferably disposed on both sides of the filter element 28 and moved towards each other in a pressing movement. Because of this, the bulges 52 - in this case the folds 54 - are mechanically compacted in certain areas, in particular mechanically compressed. In particular, the support layers 80 can be interlocked with one another by mechanical pressing so that a particularly durable connection can be produced. The filter layer 78 disposed between the support layers 80 is also compacted, in particular compressed, during the pressing operation. This results in a higher density of the attachment portion 48.

[0136] As shown in Fig. 14, the attachment portion 48 surrounds the filtration portion 46. Because of this, escape of transverse flow within the filter element 28 across the attachment portion 48 can preferably be completely prevented.

[0137] As a result of the mechanical compacting, in particular the mechanical compression, especially preferably the pressing, the attachment portion 48 forms flange surfaces on both sides of the flange section 68 for arranging the filter element 28 on the filter cartridge body 26. Because of this, the filter element 28 is designed particularly flexible for being arranged on the filter cartridge 24.

[0138] Alternatively, it can be provided for a flat flange section 68 to be produced by a further downstream manufacturing step.

[0139] According to the embodiment, the bulges 52 here protrude bidirectionally beyond the attachment portion 48. By positioning the press jaws accordingly in relation to the filter medium 76 to be deformed (see Fig. 13), it is furthermore possible to achieve a unidirectional formation of the bulges 52. [0140] Figs. 15 and 16 show an embodiment of a tool 86 for mechanical compacting - in this case for pressing - of a filter blank designed in particular as a high temperature filter medium 76 (see Fig. 13).

[0141] The tool 86 features two tool jaws 90a, 90b movable relative to each other along a stroke axis 88. The tool jaws 90a, 90b are designed for pressing the filter blank and for forming the attachment portion 48 (see, for example, Fig. 14).

[0142] According to the embodiment, the tool jaws 90a, 90b feature for this purpose a filter medium locator 92 - here in the shape of two interlocking combs 94a, 94b - for positioning and holding the filter blank within the tool 86. The filter medium locator 92 features projections and/or recesses formed complementary to corresponding bulges 52 (see, for example, Fig. 4) of the filter element 28. During the pressing operation, the filter medium locator 92 engages in the bulges 52 of the filter element 28 and, as a result, fixes the filter element 28 within the tool 86. According to the embodiment, a squeezing or pressing of the filter blank using the filter element locator 92 does not take place. [0143] According to the embodiment shown, the filter medium locator 92 is circular (directed into the projection plane) and thus designed for fixing a circular ring-like filter element 28 - in particular an axial filter element 34 (see, for example, Figs. 3 and 4).

[0144] The tool 86 or the tool jaw 90a features a press block 96 and the tool jaw 90b features a pressing punch 98. The press block 96 and the pressing punch 98 can be movable along the stroke axis 88 of the tool 86 relative to the filter medium locator 92 of the respective tool jaw 90a, 90b. In other words, the press block 96 and the pressing punch 98 can be stroke-extending and/or stroke-shortening, respectively. According to the embodiment shown, the pressing punch 98 is designed to be movable and the press block 96 is designed to be immovable relative to the respective filter element locator 92. By positioning the press stock 96 and the pressing punch 98 with respect to the filter element locator 92, the position of the attachment portion 48 with respect to the bulges 52 can be determined.

[0145] According to the embodiment shown, the tool 86 or the tool jaw 90a features a cutting die 100 and the tool jaw 90b a cutting punch 102. The cutting die 100 and the cutting punch 102 can serve to trim the filter element 28 after formation of the attachment portion 48. Preferably, the filter element 28 is trimmed directly at the extreme end of the attachment portion 48 by the cutting die 100 and the cutting punch 102. For this purpose, the cutting die 100 and the cutting punch 102 can be designed to extend or shorten the stroke with respect to the filter element locator 92 and/or the pressing punches 96a, 96b.

[0146] Fig. 15 shows the tool 86 in an open state. The tool 86 is prepared to receive a filter blank, in particular a high temperature filter medium 76 (see Fig. 13). After insertion of the filter blank, the tool 86 can then proceed to a closed state of the tool jaws 90a, 90b as shown in Fig. 16. Preferably, the filter medium locator 92 is first moved along the stroke axis 88 to fix the filter blank. Subsequently, the pressing punch 98 is moved along the stroke axis 88 towards the press block 96 to form the attachment portion 48 by mechanically compacting the filter blank in some areas. Subsequently and/or simultaneously, the cutting punch 102 can be moved along the stroke axis 88 to the cutting die 100 to trim the filter blank at the extreme edge of the mechanically compacted area.

[0147] The tool 86 can then be opened by moving the tool jaws 90a, 90b along the stroke axis

88 and the finished filter element 28 can be removed.

Reference Signs List

10 Disc brake

12 Brake disc

14 Brake caliper

16 Brake dust particulate filter

18 Main direction of rotation

20 Filter holder

22 Filter housing

24 Filter cartridge

26 Cartridge body

28 Filter element

30 Radial filter element

32 Radial main through-flow direction of the radial filter element 30

34 Axial filter element

36 Axial main through-flow direction of the axial filter element 34

38 Flow path

40 Brake caliper end section

42 Brake disc end section

44 Filter element recess of cartridge body 26

46 Filtration portion of the filter element 28

48 Attachment portion of the filter element 28

50 Edge of the filter element recess 44

52 Bulges

54 Folds

56 Bulge height

58 Bulge length

60 Bulge width

62 Interior space of the cartridge body 26

64 Environment

66 orthogonal plane

68 Flange section of the attachment portion 48

70 Recess

72 Curvature axis

74 Single layer arrangement

76 High temperature filter medium

78 Heat-resistant filter layer

80 Support layer

82 Folding device

84 Folding knife

86 Tool

88 Stroke axis of the tool 86

90a, 90b Tool jaws

92 Filter medium locator

94a, 94b Comb

96 Press block

98 Pressing punch

100 Cutting die

102 Cutting punch