Separation device for brake dust generated by a wheel brake of a motor vehicle, wheel and motor vehicle

Abstract

The invention relates to a separation device for brake dust generated by a wheel brake of a motor vehicle, wherein the separation device is configured to be fixedly arranged on a wheel of a motor vehicle for conjoint rotation therewith. The separation device has a flow path, which has at least a first portion with a first flow direction and a second portion with a second flow direction, wherein the first portion adjoins the second portion in a boundary region, and wherein the second flow direction forms an angle with the first flow direction of at least 45°, preferably of at least 60° and particularly preferably of at least 90°. The separation device further comprises a pressure difference-generating element for generating a pressure difference between an inlet pressure at the inlet of the flow path and an outlet pressure at the outlet of the flow path, wherein a collecting portion for brake dust is arranged between the boundary region and the outlet of the flow path. The invention further relates to a wheel for a motor vehicle having such a separation device and to a motor vehicle having such a separation device or having such a wheel.

Description

[0001] Description

[0002] Separation device for brake dust generated by a wheel brake of a motor vehicle, wheel and motor vehicle

[0003] The invention relates to a separation device for brake dust generated by a wheel brake of a motor vehicle. The invention further relates to a wheel for a motor vehicle and a motor vehicle.

[0004] Traffic-related emissions are subject to public criticism because they contribute to climate change and are considered harmful to health. This particularly applies to exhaust gases and pollutants emitted by combustion engines, but also to other emissions, such as dust resulting from friction brake wear, whose particle size can be in the range of so-called particulate matter. This dust generated by braking is also referred to as brake dust. Emissions from combustion engines have long been regulated by limit values. Currently, there is no legal regulation of brake particle emissions. Consequently, due to the regulation of exhaust emissions, the proportion of brake particles or brake dust in the total environmentally relevant vehicle emissions has continuously increased.Since some of the particles fall into the particulate matter size class (< 10 pm), these particulate matter sources are particularly relevant to human health. Regulation of particulate emissions from brakes is expected in the future. A current legislative proposal includes a limit of 7 mg / km per vehicle (M1, N1), expected to apply until December 31, 2034. This limit is expected to be further reduced to 3 mg / km at a later date. Due to these new requirements, innovative solutions are required to comply with the future limit values. The present invention addresses this issue and is intended to contribute to reducing the environmental pollution resulting from brake emissions.

[0005] Various devices for filtering brake dust are known from the prior art. DE 102012 016 834 A1 describes a brake dust collection device for motor vehicles, which advantageously collects the brake dust in a dust collection device when the vehicle's wheel brake is applied. The brake dust collection device comprises at least one filter element in a filter element receptacle. The filter element receptacle is formed at least by an opening in the rim and / or a space between the rim and non-rotating vehicle parts, in particular a wheel carrier.

[0006] DE 10 2016 014 115 A1 also describes a brake dust collection device consisting of an internal filter that covers the wheel rim openings on the inside.

[0007] DE 202007 000246 U1 describes a brake dust collection device consisting of an airflow generation device for generating an airflow that captures the brake components of a vehicle wheel brake and feeds brake dust from the wheel brake to a dust collection device. Furthermore, the airflow generation device is designed as at least one rotating fan blade. The dust collection device comprises at least one filter element.

[0008] DE 102018 124405 B4 describes a brake dust particle filter designed as a ring-shaped housing with an interior chamber that has an axially formed drainage recess at the lowest point for the outflow of fluid. In addition, the housing has an external, predominantly axially extending guide at the drainage recess, which serves to convey the fluid.

[0009] DE 102017 009 746 A1 describes a rim with cover elements, wherein the rim has at least one cover element assigned to the intermediate space, in each of which a filter element is arranged which is designed to filter brake dust particles from the air flowing through the intermediate spaces.

[0010] DE 202006 012 712 U1 describes a motor vehicle rim brake dust guard which has a metal disc that is attached to the wheel mounting bolts and is intended to prevent brake dust from reaching the outer side of the rim.

[0011] DE 202020 117 109 A1 describes a vehicle wheel with an air-permeable brake dust collection device that covers the spoke spaces and has at least one support element and at least one flat filter element attached thereto. A disadvantage of the described concepts is that they each use filter devices that can be susceptible to environmental influences and are typically characterized by replacement intervals and thus increased financial expenditure. Furthermore, excessive contamination can damage the filter element to such an extent that replacement is necessary. In addition, the co-rotating filter elements are subjected to high stresses, particularly at high speeds. It is conceivable that filter elements could be damaged or wear out quickly at high rotation speeds and, for example, under the influence of moisture.

[0012] The object of the present invention is therefore to provide a robust and cost-effective way to avoid or reduce the emission of brake dust particles from a motor vehicle.

[0013] The object is achieved according to the invention by a separation device of the type mentioned at the outset, wherein the separation device is designed to be arranged in a rotationally fixed manner on a wheel of a motor vehicle, and wherein the separation device has a flow path which has at least a first section with a first flow direction and a second section with a second flow direction, wherein the first section adjoins the second section in a boundary region, and wherein the second flow direction forms an angle of at least 45°, preferably of at least 60° and particularly preferably of at least 90° with the first flow direction, wherein the separation device has a pressure difference generating element for generating a pressure difference between an inlet pressure at the inlet of the flow path and an outlet pressure at the outlet of the flow path,and wherein a collection section for brake dust is arranged between the boundary region and the outlet of the flow path. Various angles are possible for the angle formed by the sections of the flow path. For example, the angle can be 90°, more than 90°, or more than 120°. The angle can, for example, be between 60° and 120°, between 45° and 170°, or between 90° and 150°. It is also conceivable for several flow sections to merge into one another one after the other, forming partial angles with each other, which then add up to a total angle. The same angle sizes and ranges as mentioned above are possible for the total angle. A separation device is understood in particular to mean a device that is suitable for preventing brake dust generated during a braking process frominto the vehicle's surroundings. The separation device can capture the brake dust and bind it spatially. In other words, the separation device can cause the brake dust to be collected in a confined volume. The separation device can also be referred to as a collection device.

[0014] A pressure difference generating element can, in particular, be a mechanical element capable of causing a change in the pressure within the traversed air volume or an adjacent air volume by moving through it. It can also be referred to as an element for generating a pressure difference.

[0015] The fact that the separation device is arranged in a rotationally fixed manner on a wheel of the motor vehicle is understood in particular to mean that the separation device rotates together with the wheel of the motor vehicle about its axis when the motor vehicle is moving. There is therefore no relative movement and in particular no relative rotational movement between the separation device and the wheel of the motor vehicle. However, it is possible for the separation device to also have movable elements which can accordingly also execute movements relative to the wheel of the motor vehicle. However, the separation device as a whole is firmly connected to the wheel of the motor vehicle so that it rotates together with the wheel of the motor vehicle about the associated axis as described.

[0016] In the context of the present description, a flow path is understood in particular to be a delimited volume with an inlet and an outlet. In most cases, such a flow path has a channel-like shape. In practice, in other words while the motor vehicle is moving, the flow path is generally flowed through by a gas and in particular by an air stream. A flow path can in particular be provided to transport or guide a gas stream, for example an air stream or an air stream carrying brake particles. The gas stream can enter the flow path through an inlet, follow the course of the flow path and exit the flow path through an outlet. If the flow path extends in sections along different directions, the flow direction of the gas stream flowing through the flow path also changes in sections.The course of the flow path boundary, for example, the walls of the flow path, causes a deflection of the gas flow or a change in the direction of the gas flow. In particular, the flow path can provide an air-permeable connection between an inner side of the separation device and an outer side of the separation device.

[0017] For the purposes of this description, an angle formed by sections of a flow path or by flow directions is understood to mean, in particular, the angle formed by a direction of the second section or a second flow direction with an imaginary extension of the first direction or the first section. If the second flow direction runs antiparallel to the first flow direction, the corresponding angle is 180°. If, for example, the second flow direction runs perpendicular to the first flow direction, the angle between the two flow directions is 90° and not 270°, as could in principle be constructed geometrically.

[0018] According to the invention, it was recognized that it is possible to remove a significant proportion of the brake dust from the air stream flowing through the brake by exploiting the inertia of the massive brake particles. Figuratively speaking, the direction of the air stream is suddenly or sharply changed, so that heavier particles, and in particular brake particles with a diameter larger than a limiting diameter, the so-called cut-off diameter, cannot follow the change in direction and a large proportion collide with a boundary or wall of the flow path and are bound there. In this way, a large proportion of the brake particles carried by the air stream can be removed from the air stream. The air stream can therefore be cleaned of a large proportion of the brake particles.Since primarily the larger brake particles are separated, there is a significant effect on the mass fraction of brake particles that are still present in the air flow entering the environment of the vehicle.

[0019] The advantages of the vehicle wheel according to the invention are, in particular, the provision of a robust brake dust separation device or separation device for brake dust that is virtually insensitive to external influences and driving scenarios. Should the entire system (pressure difference generation element, e.g., in the form of turbine-like blades, and separation system consisting of an accelerating element and a collection system) become contaminated or clogged, for example, by road dust or brake dust clumped due to moisture, this can be remedied by the vehicle owner from the outside via the outlet(s) of the vehicle wheel using simple measures (e.g., a high-pressure cleaner).Advantageously, the components of the brake dust separation device can be designed sufficiently robust for this purpose, meaning that materials can be used that are resistant to mechanical influences and avoid chemical reactions. Furthermore, the wheel according to the invention and the separation device according to the invention offer the advantage that brake dust particles separated in the collection system can be washed out by moisture (e.g., rain or vehicle cleaning), thus cleaning the collection system. The particles are bound by the influence of moisture, thereby reducing their relevance with regard to environmental problems (fine dust).This self-cleaning effect is enhanced by the effect of centrifugal force when the vehicle wheel rotates. The air flow through the entire system dries the brake dust separation device and carries away brake dust particles dissolved in the fluid. During continuous use, the vehicle wheel can thus be used in such a way that the particles separated during a certain distance are dissolved or washed out by the influence of moisture, which then cleans the brake dust separation device.

[0020] The advantage of the vehicle wheel according to the invention is therefore to provide a brake dust separation device which collects the brake particles produced by a friction brake and does not require any change intervals or the replacement of individual elements.

[0021] There are a number of adjustable parameters for controlling the separation process. For example, the size of the cross-section of the flow path can be modified, thereby influencing the flow velocity. The free path available for a braking particle to change direction and continue following the airflow without colliding with a wall of the flow path can also be modified. It is possible for the collection section to be located on a wall of the second section of the flow path. The collection section can be located at a point on the flow path where an imaginary extension of a line running in the center of the first section of the flow path along the first flow direction intersects the wall of the second section of the flow path.The collection section can also be located a short distance downstream from the previously described location, since the brake particles separated in the collection section also generally initially undergo at least a small change in direction. The collection section is, of course, not point-shaped, but rather corresponds to a flat area, which can, in particular, correspond to an area around the previously described locations. The collection section can, for example, be rectangular, circular, oval, or elliptical. It is possible to provide external access to the collection section, which allows for cleaning the collection section.

[0022] It is also possible for the collection section to be formed by an undercut in the second section of the flow path. In other words, the second part of the flow path can be split, with the part of the second flow path whose associated flow direction deviates less from the first flow direction having a closed end. This part can be referred to as the closed part. Figuratively speaking, this part corresponds to a "dead end" for the braking particles. The braking particles that enter the closed part can therefore only leave the closed part again by a complicated and statistically very improbable change of direction. Even particles that fall off a wall of the closed part are ultimately almost completely absorbed.

[0023] It is also conceivable for the collection section to be formed by a depression or trough in the second section of the flow path. This also provides geometric advantages for collecting or absorbing the brake particles.

[0024] In an advantageous development, a surface of the collection section is partially or completely roughened and / or coated. The coating can also consist of an adsorption-promoting material or a material with increased roughness. This increases the probability that an impacting brake particle will be bound to the wall.

[0025] The separation device can be designed to be rotationally symmetrical or have at least a 10-fold symmetry axis, for example at least or exactly a 12-fold symmetry axis, at least or exactly a 16-fold symmetry axis, at least or exactly a 20-fold symmetry axis, at least or exactly a 24-fold symmetry axis or at least or exactly a 30-fold or 32-fold symmetry axis.

[0026] A preferred embodiment provides for the separation device to be constructed in one piece. This results in reduced production costs and generally simple assembly. The separation device can be made of a plastic, for example. Alternatively, the separation device can be made of a metal or a composite material. It is possible for the separation device to be manufactured using an injection molding process. Alternatively, the separation device can also consist of several components. One, several, or all of these components can be rotationally symmetrical and stacked or joined in the axial direction, i.e., in the direction of the axis of the wheel on which the separation device is or will be arranged.

[0027] In an advantageous embodiment, the separation device is designed for mounting on a wheel of a motor vehicle. This results in a modular design and the possibility of retrofitting existing vehicles with a separation device according to the invention.

[0028] It is possible for the separation device to have a plurality of first sections of the flow path and / or a plurality of second sections of the flow path. If the separation device has a plurality of first sections of the flow path, there can be multiple inlets to the first sections of the flow path. In other words, the separation device can have a plurality of openings on its side facing the brake, through which the air flow containing brake particles can enter the separation device. Each opening can belong to a first portion of the flow path. The first portions of the flow path can be combined with one another as the flow path progresses. For example, the first portions of the flow path can be arranged in a star shape. They can then flow into a common second portion of the flow path.However, it is also conceivable that each first portion of the flow path has a corresponding second portion of the flow path. A corresponding number of transition regions and separation regions can then be present. In other words, it is possible for the separation device to have several flow paths connected in parallel.

[0029] It is possible for a flow-influencing element, which can be formed, for example, by the openings described above, to be designed in the form of a nozzle, for example, after which the diameter of the space through which the air flows narrows and the flow velocity is thereby increased. The nozzle can, for example, have a circular shape or any other shape, such as a rectangular shape. It is also conceivable for several nozzles to be assigned to a collecting element as flow-influencing elements. The separation efficiency is influenced by the proportion of particles deposited on the impact surface. In order to improve the separation efficiency, it is conceivable for the impact surface to be designed using an advantageous material or substrate, thereby improving the adhesion of the particles. It is also conceivable to provide advantageous surface structures or roughness.

[0030] According to one embodiment, a flat portion of the separation device completely covers the gaps between a hub section and the spokes connecting the rim of a motor vehicle wheel, with at least one inlet of the flow path being arranged in the flat portion. This prevents a parallel air flow from flowing past the separation device into the surroundings of the motor vehicle, thus preventing brake particles from escaping uncontrollably into the environment.

[0031] According to a further development of the invention, the separation device comprises a plurality of pressure difference generating elements arranged in a turbine-like or compressor blade-like manner in a peripheral region of the separation device. These pressure difference generating elements rotate with the wheel of the motor vehicle as the vehicle moves, making it possible to influence the flow velocity of the air flow. By appropriately designing the pressure difference generating elements, for example, an increase in the pressure on the inlet side of the flow path or a decrease in the pressure on the outlet side of the flow path can be achieved. Both options lead to an increase in the pressure difference between the inlet of the flow path and the outlet of the flow path, thus causing an increase in the flow velocity through the flow path.Such an increase in flow velocity through the flow path tends to be beneficial, as it also accelerates the brake particles to higher speeds, which increases the reliability of the brake particle separation process. Such an increase in the pressure difference can also lead to more efficient cooling of the brakes.

[0032] It is advantageously possible for pressure difference generating elements to be arranged and designed at an outer end of the separation device, viewed in the axial direction, in order to reduce an air pressure at the outlet of the flow path compared to an air pressure at the inlet of the flow path. Alternatively, it is also possible for the pressure difference generating elements to be arranged and designed at an inner end of the separation device, viewed in the axial direction, in order to increase an air pressure at the inlet of the flow path compared to an air pressure at the outlet of the flow path. In any case, it is advantageous if there is a pressure drop from the brake-side end of the flow path towards the end of the flow path remote from the brake. As a result, the desired air flow is generated or intensified by the separation device and the brake particles are transported away from the brake.

[0033] Preferably, the separation device is designed to be reversibly attachable to a wheel of a motor vehicle. This enables simple assembly, disassembly, cleaning, and replacement of the separation device. In particular, the separation device can be arranged between the rim spokes of the wheel. It is conceivable to provide a separate separation device for each spoke or for each free space between two spokes. However, it is also conceivable to provide a single separation device, for example in the form of a rim cover, for the entire wheel. The free spaces between the spokes can be partially or completely covered by the separation device.

[0034] According to one embodiment, the separation device can have at least one pressure difference generating element variable in its position and / or orientation. In particular, the pressure difference generating element can be designed to be rotatable about a torsion axis. The pressure difference generating element can be designed such that a torsion angle of the pressure difference generating element changes depending on a centrifugal force or a centrifugal force. The centrifugal force or the centrifugal force can be generated by a rotation of the wheel of the motor vehicle on which the separation device is arranged. In this way, it can be achieved that the magnitude of the generated pressure difference is dependent on the speed of the motor vehicle. The development of brake dust particles is also speed-dependent and dependent on the strength of a braking operation performed.By cleverly designing the pressure difference generation elements, it is possible to ensure that the separation efficiency always meets the required criteria. The pressure difference generation elements can also be designed in such a way that the mass flow or volume flow through the separation device is kept constant regardless of the speed of the motor vehicle on whose wheel the separation device is mounted.

[0035] In other words, it is possible for an orientation of a pressure difference generating element to vary depending on a rotational speed of the separation device and / or depending on a linear speed of a motor vehicle on which the separation device is arranged.

[0036] It is also possible for the separation device to have a plurality of flow paths and a plurality of collection regions, wherein a collection region can be assigned to each flow path. In a specific development, the separation device has a plurality of flow paths and collection regions, wherein some or all of the flow paths complement one another linearly to form an overall flow path. In other words, the separation device can be constructed in several stages. The air and particle flow flowing through the separation device is then subjected to a change of direction several times. Accordingly, several collection regions can then be present. It is possible for each individual flow path of the plurality of flow paths to be designed to separate a specific mass range or a specific diameter range of the brake particles.An example of the sequence along the air flow in such a multi-stage separation device would be.

[0037] 1. A first section of the flow path along a first direction,

[0038] 2. A first transition area,

[0039] 3. A second section of the flow path along a second direction,

[0040] 4. A second transition area and

[0041] 5. A third section of the flow path along a third direction.

[0042] The second section can have a first collecting section, and the third section can have a second collecting section. The third direction can run parallel to the first direction. In particular, the first direction can form an angle of 90° with the second direction, and the second direction can also form an angle of 90° with the third direction. The design can, in principle, be expanded as desired with additional sections and collecting areas.

[0043] According to a preferred embodiment, the flow path has a completely free cross-section at every point along the flow path. In other words, the flow path is a geometrically simple, tube- or box-shaped, channel-like area in which no grids, filters, or the like are arranged. According to the invention, filter elements can therefore be dispensed with in the design of the separation device, since the principle of inertial separation or impaction is used to remove the brake particles from the air stream or aerosol stream.

[0044] Advantageously, the present concept can also be designed as a multi-collection system, with at least two separation systems arranged one behind the other being conceivable. This allows the amount of particulate matter to be separated to be increased and reduces the risk of overloading or rebound effects, which negatively impact collection efficiency. Furthermore, by arranging at least two collection systems one behind the other, the separation diameter of the particles to be separated by each collection system can be adjusted as desired, thereby advantageously separating the widest possible spectrum of particulate matter.

[0045] Furthermore, it can be advantageous if the turbine-like elements and / or flow-influencing elements can be modified in such a way that, for example, even when the rotational speed of the vehicle wheel changes, the flow velocity of the particle-laden airflow remains constant, thus ensuring the most constant separation efficiency possible. This can be achieved, for example, by the influence of centrifugal force changing the position of the blades of the turbine-like element as the rotational speed increases. It is also conceivable, for example, for the shape of the nozzle of the flow-influencing element to change as the rotational speed increases; this can be implemented, for example, by a sliding mechanism that changes the nozzle opening as the centrifugal force increases. In both variants, a narrowing of the space through which the air flows can result in a reduction in the flow velocity.The result is an almost constant volume flow.

[0046] The object is further achieved by a wheel for a motor vehicle with a separation device according to the invention. The object is also achieved by a motor vehicle with such a separation device and / or with at least one wheel with such a separation device.

[0047] A further development of such a motor vehicle can include a front spoiler designed to reduce air pressure on the outside of at least one front wheel of the motor vehicle while the motor vehicle is traveling. This allows further influence on the desired pressure conditions and thus on the airflow through the flow path. Embodiments of the invention are explained in more detail with reference to the drawings and the following description. They show:

[0048] Fig. 1: a perspective exploded view of a first embodiment of a wheel 1 according to the invention with a separating device according to the invention,

[0049] Fig. 2: a partial cross-section through a second embodiment of a separating device according to the invention,

[0050] Fig. 3: a partial cross-section through a third embodiment of a separating device according to the invention,

[0051] Fig. 4: a partial cross-section through a fourth embodiment of a separating device according to the invention,

[0052] Fig. 5 shows a fifth embodiment of a separating device according to the invention in three different views,

[0053] Fig. 6 shows a sixth embodiment of a separating device according to the invention in three different views and

[0054] Fig. 7 shows a seventh embodiment of a separation device according to the invention in two different views.

[0055] Figure 1 shows a perspective exploded view of a first embodiment of a wheel 1 according to the invention with a separation device 2 according to the invention. For the sake of clarity, the wheel 1 is shown without spokes, so that only the rim 4 is shown. The brake (not shown) is arranged in the open area of ​​the rim 4, or slightly offset inward in the axial direction. This brake generates the brake particle 36 during a braking operation and releases it into the air in the interior of the rim 4.

[0056] The guide element 6 can also be seen, which is flat or plate-like and has a circular circumference. The guide element 6 has a central region 18 and a plurality of recesses 16. The guide element 6 is adapted to the rim 4 such that the basic shape of the guide element 6 completely covers the open area of ​​the rim 4. In particular, the guide element 6 is designed to be connected to the rim 4 in an airtight or essentially airtight manner in the region of its circumference. The guide element 6 has recesses 16 which enable a directed flow through the guide element 6 of an air stream which entrains brake particles such as, for example, the brake particle 36. In the case shown, the recesses 16 are designed as part-circular elongated holes. In the illustrated embodiment, these are arranged near the circumference of the guide element 6.Alternatively, however, it is also possible for the recesses 16 to have a different position in the radial direction. For example, the recesses 16 can be arranged near the center axis of the guide element 6. It is also possible for the recess to consist of a central opening, for example, a circular opening. It is also possible for a larger or smaller number of recesses, for example, one, two, four, five, six, eight, ten, or more, to be present, rather than the three recesses 16 shown. The guide element 6 can also be referred to as a flow-influencing element.

[0057] The illustrated embodiment further comprises a spacer element 8, which has a ring element 20 and a central opening 22. The extent of the central opening 22 in the radial direction is significantly greater than the extent in the radial direction of the ring element 20. The spacer element 8 imparts a distance in the axial direction between the guide element 6 and the adjoining collecting element 10. The collecting element 10 can be designed as a baffle plate. In this way, it is possible for a braking particle 36 to move between the guide element 6 and the collecting element 10 in the radial direction as well. The portion of the path 32 of the braking particle 36 through the recesses 16 of the guide element 6 corresponds to the first portion of the flow path. The portion of the path 32 of the braking particle 36 that runs in the radial direction at the level of the spacer element 8 corresponds to the second portion of the flow path.A large portion of the brake particles carried by an air flow along path 32, in particular the brake particle 36 shown, strikes a surface of the collecting element 10, and in particular a radially extending surface of the base body 24 of the collecting element 10. In the figure, this corresponds to the invisible surface or the surface of the collecting element 10 oriented toward the spacer element 8. The collecting section can be arranged in this area. For the illustrated embodiment, the through-opening 26 corresponds to the exit of the flow path.

[0058] The right-hand section of the figure shows the turbine element 12. It is also connected in a rotationally fixed manner to the other components, in particular to the collecting element 10. It consists of a plate-shaped base element 28 and a plurality of pressure difference generating elements 30 in the form of blade elements distributed around the circumference of the base element 28. In the assembled state, the base element 28 is arranged at a distance in the axial direction from the surface of the collecting element 10 facing it, which distance approximately corresponds to the axial extent of the blade elements 28. Due to the rotational movement that the turbine element 12 performs together with the entire wheel 1, the pressure difference generating elements 30 effect a modification of the pressure on the outside of the collecting element 10.In particular, a reduction in the pressure in this area can be achieved so that the flow velocity of the air flow 34, which is also indicated in the figure, can be increased.

[0059] Figure 2 shows a partial cross-section through a second embodiment of a separation device 2 according to the invention. The separation device 2 again consists of the guide element 6, the spacer element 8 and the collecting element 10. The guide element 10 has a recess 16 which allows the braking particles 36 to move in the axial direction. The recess 16 arranged between the outer region of the guide element 6 and the central region 18 of the guide element 6 forms a first section of the flow path. The second section of the flow path adjoins the spacer element 8. The second section of the flow path extends at an angle of 90° to the first section of the flow path, so that the braking particles 36 are entrained by the air flow, which changes direction in this region, and flow into the region between the collecting element 10 and the central region 18 of the guide element 6.A plurality of braking particles 36.1, 36.2, 36.3 and 36.4 are shown, each having different diameters and thus different masses. Due to the different diameters and the different masses, the braking particles 36.1, 36.2, 36.3 and 36.4 move on different trajectories. Initially, the braking particles 36 move from top to bottom in the first part 40.1 of the flow path 40, and are then deflected towards the second part 40.2 of the flow path 40. In other words, the different braking particles 36.1, 36.2, 36.3 and 36.4 are deflected to different degrees, with the lightest braking particle 36.4 being able to follow the air flow most easily and, after just a short distance, having a velocity vector whose direction is identical to the direction of extension of the second section of the flow path. The heaviest of the brake particles shown is 36.1, on the other hand, is deflected only slightly and impacts the collection section 38, which can also be referred to as the separation zone. The two medium-mass braking particles 36.2 and 36.3 experience a moderate change in direction and may also impact the surface of the collection element 10 in an area not shown in the figure, where they are also separated.

[0060] Figure 3 shows a partial cross-section through a third embodiment of a separation device 2 according to the invention. The illustrated separation device 2 differs from the second embodiment shown in Figure 2 only in that the collecting section 38 is arranged in a trough in the collecting element 10. The surface of this trough can be roughened or coated.

[0061] Figure 4 shows a partial cross-section through a fourth embodiment of a separation device 2 according to the invention. The separation device 2 shown differs from the second embodiment shown in Figure 2 only in that the collecting section 38 is formed by an undercut in the collecting element 10. The separating section 44, which is part of the base body 24 of the collecting element 10, divides the collecting element 10 into two regions, namely the collecting section 38 in the form of a separation zone and the second section of the flow path arranged above it. The collecting section 38 has an end section 42 or an end wall oriented perpendicular to the direction of extension of the separation zone. In this embodiment, the collecting section 38 is closed on five sides and open on only one side.In other words, in the illustrated embodiment, the collecting section is designed such that a centrifugal force resulting from rotation of the wheel pushes the brake particles into the collecting section and prevents the brake particles from escaping from the collecting section or from the collecting section 38.

[0062] Figure 5 shows a fifth embodiment of a separation device 2 according to the invention in three different views. From left to right, a first sectional perspective view, a cross-section, and a second sectional perspective view are shown. The turbine element is not shown in each case. The guide element, the spacer element, and the collecting element are designed as a single component and can be manufactured, for example, using an injection molding process.

[0063] The separation device 2 has a plurality of recesses 16, which serve as an inlet for the brake particles or for an air stream carrying the brake particles. The recesses 16 are arranged in the radially outer region of the surface 46 facing the brake and are designed as elongated holes. They can have a radial extent of, for example, between 5% and 20% of the radius of the separation element 2. In the illustrated embodiment, four recesses 16 are present, each of which describes a pitch circle of approximately 80° along the circumference of the separation element 2. The separation element 2 further has, on the surface 46 facing the brake, a plurality of web-shaped air guide elements 48 extending in a star shape from the center of the surface 46 to the circumference.Adjoining the inlet openings in the form of the recesses 16 within the separation device 2 is a channel-shaped flow path 40, which guides an air flow that enters the separation element 2 through the recesses 16 radially inward. The cavity forming the flow path 40 can be rotationally symmetrical. A plurality of first projections 50 and second projections 52 are arranged in the flow path 40, alternating from radially outside to radially inside. The first projections 50 are arranged on the first side 54 of the flow path 40 facing the brake, and the second projections are arranged on the second side 56 of the flow path 40 facing away from the brake.In the illustrated embodiment, two first projections 50 and three second projections 52 are provided, which are arranged alternately on the first side 54 and on the second side 56 of the flow path 40, viewed from radially outside to radially inside, and project into the flow path 40. In this way, they influence the air flow and cause several changes in the direction of the air flow.

[0064] The first projections 50 and the second projections 52 overlap in the radial direction, so that sections of the flow path 40 are created in which the primary flow direction deviates by 90° from the previous section in the flow direction. Sections of the flow path 40 in which a primary air flow direction runs in the radial direction alternate with sections of the flow path 40 in which the primary air flow direction runs in the axial direction. The first projections are web-like and narrow in the radial direction, whereas the second projections 52 have an extension in the radial direction that is significantly greater than their extension in the axial direction. The ratio of the extension in the radial direction to the extension in the axial direction can be, for example, between 2:1 and 6:1.The second projections 52 have a radially inwardly extending, sloping flank, which results in an enlargement of the cross section of the flow path 40 along the flow direction.

[0065] A total of two first projections 50 and three second projections 52 are provided, one of the second projections 52 bordering the circumference of the separation device 2 and the second projection 52 arranged closest to the axis having a greater extent in the axial direction than the two other second projections 52. The flow path 40 runs through the projections 50, 52 towards the through-opening 26, which is circular in shape and is arranged in the surface 58 of the separation device 2 facing away from the brake. The through-opening 26 is designed as a central opening and can have an extent in the radial direction or a diameter of, for example, between 10% and 30% of the diameter of the separation device 2.

[0066] A possible path of an air flow 34 is indicated by the dashed line. The air flow 34 undergoes several changes of direction, each of which leads to the deposition of entrained particles, and in particular, brake particles, on the surfaces 54, 56 and / or on the projections 50, 52.

[0067] Figure 6 shows a sixth embodiment of a separation device 2 according to the invention in three different views. From left to right, a first sectional perspective view, a cross-section, and a second sectional perspective view are shown. The turbine element is not shown in each case. The guide element, the spacer element, and the collecting element are again designed as a single component.

[0068] In the illustrated embodiment, the inlet openings 26 are again designed as elongated holes. There are first inlet openings 26.1 and second inlet openings 26.2, with the first inlet openings 26.1 being arranged radially further outward than the second inlet openings 26.2. In the circumferential direction, the first inlet openings 26.1 and the second inlet openings 26.2 are arranged roughly alternating and overlapping. This provides two entry options for the air flow 34, which differ in their radial position.

[0069] In the sixth exemplary embodiment shown, the flow path is designed without projections and with flat walls. It has a first channel section 60, a reversal region 62, in which the air flow 34 experiences a change of direction of roughly 180°, and a second channel section 64. The second channel section 64 widens from the radially inside to the radially outside, thus increasing its cross-section in the flow direction of the air flow 34. At the end of the second channel section 64, the outlet openings 66, through which the air flow 34 leaves the separation device 2, are arranged on the circumference of the separation device 2. The air flow runs in the radial direction primarily from the outside towards the center of the separation device 2 through the first channel section 60 and back out in the second channel section 64.Thus, both the recesses 16 as inlet openings and the outlet openings 66 are arranged in a radially outer region of the separation device 2. In the illustrated embodiment, the brake particles are separated primarily in the reversal region 62 and there, in particular, on the end wall 70.

[0070] Figure 7 shows a seventh embodiment of a separation device 2 according to the invention in two different views. From left to right, a first sectional perspective view and a second sectional perspective view are shown. In each case, the turbine element is not shown. The guide element, the spacer element, and the collecting element are again designed as a single component.

[0071] The seventh exemplary embodiment has a recess 16 in the form of a central inlet opening through which the air flow 34 enters the separation device 2. The air flow 34 exits the separation device 2 through the outlet openings 66. The separation device 2 has a plurality of flow paths 40, each associated with a circular segment 72, which define a flow direction from radially inward to radially outward. The air flow 34 thus enters the separation device 2 through the central inlet opening, flows through it from radially inward to radially outward, and exits the separation device through the outlet openings 66. The circular segments 72 are each delimited by the radially extending separating webs 74.

[0072] A plurality of first projections 50 and second projections 52 are arranged in the flow paths. The projections 50, 52 are designed in an undercut manner and represent geometric traps for the brake particles carried by the air flow 34. The projections 50, 52 each have an axially extending section 50.1, 52.1, which is adjoined by a radially extending section 50.2, 52.2, which extends from the axially extending section 50.1, 52.1 in a direction opposite to the primary flow direction of the air flow 34 in the respective section. List of Reference Symbols

[0073] Wheel 38 collection section

[0074] Separator 40 flow path

[0075] Rim 42 end section

[0076] Guide element 44 separation section

[0077] Spacer element 46 surface

[0078] Collecting element 48 Air guide element

[0079] Turbine element 50 first projection

[0080] Flange element 52 second projection

[0081] Recess 54 first side of the flow path

[0082] Central area 56 second side of the flow path

[0083] Ring element 58 surface

[0084] Opening 60 first canal section

[0085] Base body 62 reversal area

[0086] Passage opening 64 second channel section

[0087] Plate element 66 exit opening

[0088] Pressure difference generating element 68 web

[0089] Path of a braking particle 70 Bulkhead Airflow 72 Circle segment

[0090] Brake particles 74 separator

Claims

Patent claims 1. Separation device for brake dust generated by a wheel brake of a motor vehicle, wherein the separation device (2) is designed to be arranged in a rotationally fixed manner on a wheel (1) of a motor vehicle, and wherein the separation device (2) has a flow path (40) which has at least a first section (40.1) with a first flow direction and a second section (40.2) with a second flow direction, wherein the first section (40.1) adjoins the second section (40.2) in a boundary region.2), and wherein the second flow direction forms an angle of at least 45°, preferably of at least 60° and particularly preferably of at least 90°, with the first flow direction, wherein the separation device (2) has a pressure difference generating element (30) for generating a pressure difference between an inlet pressure at the inlet of the flow path (40) and an outlet pressure at the outlet of the flow path (40), and wherein a collection section (38) for brake dust is arranged between the boundary region and the outlet of the flow path (40).

2. Separation device (2) according to claim 1, characterized in that the collecting section (38) is arranged on a wall of the second section (40.2) of the flow path (40).

3. Separation device (2) according to one of the preceding claims, characterized in that a surface of the collecting section (38) is partially or completely roughened and / or coated.

4. Separation device (2) according to one of the preceding claims, characterized in that a flat portion of the separation device (2) completely covers spaces between spokes of a wheel (1) of a motor vehicle, wherein at least one inlet of the flow path (40) is arranged in the flat portion.

5. Separation device (2) according to one of the preceding claims, characterized by a plurality of pressure difference generating elements (30) which are arranged in a turbine-like or impeller-like manner in a peripheral region of the separation device (2).

6. Separation device (2) according to one of the preceding claims, characterized by at least one pressure difference generating element (30) which is variable in its position and / or in its orientation.

7. Separation device (2) according to claim 6, characterized in that an orientation of a pressure difference generating element (30) varies depending on a rotational speed of the separation device (2) and / or depending on a linear speed of a motor vehicle on which the separation device (2) is arranged.

8. Separation device (2) according to one of the preceding claims, characterized in that the flow path (40) has a completely free cross-section at every point along the flow path (40).

9. Wheel (1) for a motor vehicle, characterized by a separating device (2) according to one of the preceding claims.

10. Motor vehicle with a separation device (2) according to one of claims 1 to 8 and / or with at least one wheel (1) according to claim 9.

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