Diffuser device for a device for ascertaining particle emissions from brakes, and device

Abstract

The invention relates to a diffuser device (1) for a device (3) for ascertaining particle emissions from brakes, said diffuser device (1) having a housing (5), which extends along a flow direction (9) and defines an interior (11) that extends along the flow direction (9) and which separates the interior (11) from the surroundings (13) of the diffuser device (1) perpendicularly to the flow direction (9), and a dividing unit (7), which extends along the flow direction (9) and which divides the interior (11), perpendicularly to the flow direction (9), into a plurality of sections. The invention additionally relates to a corresponding device (3).

Description

[0001] Diffuser device for a device for determining particle emissions from brakes and device

[0002] The present invention relates to a diffuser device for a device for determining particle emissions from brakes and a corresponding device.

[0003] Diffuser devices for a device for determining brake particle emissions and corresponding devices for determining brake particle emissions are known from the prior art. These devices for determining brake particle emissions can also be referred to as brake test benches. Brake test benches with appropriate measurement technology are used to measure particle emissions, for example, from disc and / or drum brakes in cars, trucks, and / or rail vehicles. A brake can be driven by a test bench motor, and real brake load profiles can be simulated. A vehicle mass simulation can be realized by combining a real flywheel with torque control of the test bench motor. Various speeds as well as downhill and uphill driving can also be simulated.During the test run, the brake can be operated via a hydraulic actuator or, in the case of electromechanical braking systems, via a corresponding electrical control.

[0004] To measure particle emissions, the brake can be placed within a closed air duct. The area of ​​the brake test bench where the brake is placed can also be referred to as the test specimen enclosure. An air flow controlled in terms of volume flow, relative humidity, and temperature is directed horizontally in the direction of travel and, within the test bench, along a so-called flow direction over the brake to carry the emitted particles away from the brake and into a downstream measuring tunnel. Here, the number and size of the particles can be evaluated based on a partial volume flow. For example, the entire air duct, from particle generation to measurement, is operated at a negative pressure compared to the installation location to protect the operator and increase measurement accuracy.The measuring tunnel arranged downstream of the test specimen housing in the direction of flow normally has a much smaller cross-section than the test specimen housing in which the brake to be tested is mounted. This ensures, on the one hand, a completely, fully developed or undisturbed flow profile in the area of ​​the measuring tunnel as a result of a turbulent flow regime that may initially arise in the direction of flow, and thus isokinetic sampling in the area of ​​the measuring tunnel across the cross-section. On the other hand, the time required for particle conglomerates to form can be reduced by increasing the flow velocity. Typically, the cross-section of the measuring section in the measuring tunnel is designed to be the same size downstream of the test specimen housing in the direction of flow, and the cross-section of the air duct is designed to be the same size upstream of the test specimen housing in the direction of flow.Therefore, a rapid cross-sectional expansion in a diffuser device or in a diffuser of the brake test bench, seen in the direction of flow, is often necessary in front of the test specimen or in front of the test specimen housing.

[0005] In general, it is desirable for diffuser devices and devices with such a diffuser device to optimize the air flow on the device in a simple manner, in particular in a test specimen housing of the device located downstream of the diffuser device as seen along the flow direction.

[0006] It is therefore the object of the present invention to optimize the air flow on the device, in particular in a test specimen housing of the device located downstream of the diffuser device as seen along the flow direction, in a simple manner.

[0007] According to a first aspect of the invention, the stated object is achieved by a diffuser device having the features of patent claim 1. The diffuser device is configured for a device for determining particle emissions from brakes. The diffuser device has a housing extending along a flow direction. The housing defines an interior space that widens along the flow direction. The housing separates the interior space from a surrounding area of ​​the diffuser device perpendicular to the flow direction. The diffuser device also has a subdivision unit extending along the flow direction. The subdivision unit subdivides the interior space into several sections perpendicular to the flow direction.

[0008] The diffuser device is configured for the device for determining particulate emissions from brakes. The diffuser device is configured for installation in the device and preferably has fastening means with which the diffuser device can be fastened to a component of the device arranged upstream of the diffuser device, as seen in the direction of flow, such as a straight pipe section of the device, and to a component of the device arranged downstream of the diffuser device, as seen in the direction of flow, such as a test specimen housing of the device. The fastening means can have a first flange section arranged upstream of a flat section of the housing, as seen in the direction of flow, and a second flange section arranged downstream of the flat section of the housing, as seen in the direction of flow.Preferably, the flat portion of the housing has an inner wall of the housing facing the interior.

[0009] The diffuser device comprises the housing extending along the flow direction. The flow direction is preferably defined by a direction along which an air flow is guided through the diffuser device built into the device when measuring brake particulate emissions. Because the housing extends along the flow direction, the housing limits the air flow at least along a portion of the path traveled by the air flow when measuring particulate emissions.If, in the context of the present invention, a component of the diffuser device or apparatus extends along the flow direction, this is preferably understood to mean that the component extends from a corresponding first end to a corresponding second end, wherein the first end is arranged in a first plane extending perpendicular to the flow direction and the second end is arranged in a second plane extending perpendicular to the flow direction and, viewed along the flow direction, the first plane is first passed by the air flow moving along the flow direction and then the second plane is passed by the air flow. The housing defines the interior space which widens along the flow direction.By defining the interior space that expands along the flow direction, the housing ensures that the flow cross-section expands along the flow direction. Preferably, the housing is configured so that the interior space continuously expands along the flow direction, ensuring particularly optimal air flow. Continuous expansion of the interior space is preferably ensured by the housing having an inner wall facing the interior space, which is configured such that the area defined by the inner wall and arranged in a plane perpendicular to the flow direction continuously increases in the flow direction.

[0010] The housing separates the interior from the area surrounding the diffuser device perpendicular to the flow direction. This ensures that no particles from the interior enter the environment near the housing, and that no particles from the environment enter the interior, allowing particularly precise measurement results to be obtained with the brake particle test bench in which the diffuser device is installed.

[0011] The diffuser device also includes a subdivision unit extending along the flow direction. Because the subdivision unit extends along the flow direction, it limits the airflow at least along a portion of the path traveled by the airflow during particle emission measurements and can thus contribute to optimizing the airflow at the device, particularly in a test specimen enclosure located downstream of the diffuser device along the flow direction.

[0012] The subdivision unit divides the interior into several sections perpendicular to the flow direction. The fact that the subdivision unit divides the interior into several sections perpendicular to the flow direction ensures that the airflow flowing through the diffuser device is divided into several airflow sections perpendicular to the flow direction. This allows the flow behavior of these airflow sections to be specifically influenced and optimized. This significantly simplifies the optimization of the airflow on the device, particularly in a test specimen housing downstream of the diffuser device along the flow direction. The subdivision unit can preferably also be referred to as a baffle unit or baffle insert.With the help of the subdivision unit, flat sections are preferably provided along which the air flow flows, whereby turbulence in the air flow can be avoided or at least significantly reduced.

[0013] In summary, it can be stated that with the aid of the diffuser device, the air flow on the device, in particular in a test specimen housing of the device located downstream of the diffuser device as seen along the flow direction, can be easily optimized.

[0014] In one embodiment, the subdivision unit is configured such that the multiple sections of the interior space expand along the flow direction. Because the subdivision unit is configured such that the multiple sections of the interior space expand along the flow direction, the subdivision unit ensures that each flow cross-section of each airflow section expands along the flow direction. Preferably, the subdivision unit is configured such that the multiple sections of the interior space expand continuously along the flow direction, which ensures particularly optimal air guidance.A continuous widening of the several sections of the interior space is preferably ensured by the fact that the subdivision unit has several walls which are designed such that the surfaces defined by the walls and lying in a plane arranged perpendicular to the flow direction continuously increase in the flow direction.

[0015] In one embodiment, the housing has first connecting means and the

[0016] Subdivision unit has second connecting means, wherein the housing and the

[0017] The subdivision unit can be detachably connected to one another using the first connecting means and the second connecting means. Due to the detachable connection, the housing and the subdivision unit can be easily disassembled and, in the event of any particle contamination, cleaned using suitable cleaning methods outside the device.

[0018] In one embodiment, the subdivision unit comprises a guide plate extending along the flow direction, which divides the interior space into the multiple sections perpendicular to the flow direction. For example, the subdivision unit comprises only one guide plate extending along the flow direction, which divides the interior space into the multiple sections perpendicular to the flow direction. This makes it possible to provide a particularly material-friendly alternative.

[0019] In one embodiment, the subdivision unit comprises a plurality of guide vanes extending along the flow direction, spaced apart from one another perpendicular to the flow direction, and dividing the interior into a plurality of sections perpendicular to the flow direction. Because the subdivision unit comprises a plurality of guide vanes extending along the flow direction, spaced apart from one another perpendicular to the flow direction, and dividing the interior into a plurality of sections perpendicular to the flow direction, backflows, i.e., a movement of air currents counter to the flow direction, can be prevented or at least the likelihood of their occurrence can be significantly reduced.Furthermore, since the subdivision unit has the plurality of guide vanes extending along the flow direction, which are spaced apart from one another perpendicular to the flow direction and which divide the interior space into the plurality of sections perpendicular to the flow direction, large-scale vortices within the diffuser device can be prevented or at least the probability of their occurrence can be significantly reduced.

[0020] In one embodiment, each guide plate of the guide plates has a rectangular, circumferential cross-sectional area extending along a plane perpendicular to the flow direction. Preferably, each guide plate of the guide plates has a square, circumferential cross-sectional area extending along a plane perpendicular to the flow direction. A rectangular, in particular square, circumferential cross-sectional area can also be referred to as a rectangular, in particular square, and hollow cross-sectional area. The rectangular, in particular square, cross-sectional area of ​​each guide plate preferably extends along a straight line along which the flow direction runs.Because each guide plate of the guide plates has a rectangular, in particular square, circumferential cross-sectional area extending along the plane perpendicular to the flow direction, at least some air flow sections can be guided by the diffuser device in such a way that, viewed along the flow direction, they also assume a rectangular, in particular square, and circumferential shape, at least in sections. A rectangular, in particular square, and circumferential shape of at least some air flow sections has led to particularly optimal flow behavior in a test specimen enclosure downstream of the diffuser device in the flow direction.Preferably, each guide plate of the guide plates has a rectangular, in particular square, circumferential cross-sectional area along the entire extent of the corresponding guide plate along the flow direction, which extends along a corresponding plane arranged perpendicular to the flow direction, thereby allowing a particularly optimal flow behavior to be achieved in the test specimen enclosure. The special case of the square circumferential cross-sectional area has led to particularly optimal flow conditions.

[0021] In one embodiment, the guide vanes are rectangular and arranged relative to one another in such a way that a first straight line of two straight lines lying in a plane perpendicular to the flow direction and intersecting in a straight line along which the flow direction runs intersects two opposite corner points of each guide vane and a second straight line of the two straight lines intersects the other two likewise opposite corner points of each guide vane.Because the guide vanes are rectangular in shape and arranged in relation to one another in such a way that a first straight line of two straight lines lying in a plane perpendicular to the flow direction and intersecting in a straight line along which the flow direction runs intersects two opposite corners of each guide vane, and a second straight line of the two straight lines intersects the other two corners of each guide vane, which are also opposite one another, a particularly optimal flow behavior is achieved. Preferably, each guide vane has a square cross-sectional area all the way around, and the two straight lines lying in the plane perpendicular to the flow direction and intersecting in the straight line along which the flow direction runs form a right angle between them. This has resulted in particularly optimal flow behavior.

[0022] In one embodiment, the diffuser device comprises a first rectifier unit extending perpendicular to the flow direction and arranged upstream of the subdivision unit, as viewed along the flow direction. The fact that the first rectifier unit extends perpendicular to the flow direction ensures that the air flow impinges on the first rectifier unit perpendicularly. Because the first rectifier unit is arranged upstream of the subdivision unit, as viewed along the flow direction, the flow behavior upstream of the subdivision unit can be adjusted using the first rectifier unit.

[0023] The first rectifier unit preferably has a plurality of bores. The bores ensure that, within the air flow directed along the flow direction, regions with a high speed are decelerated and regions with a low speed can be accelerated. For this purpose, the bores preferably have different diameters, wherein the diameters of the bores can be adapted to the geometry of the other sections of the device and in particular of the diffuser device. Furthermore, the bores ensure that a pressure drop along the flow direction at the first rectifier unit is guaranteed when an air flow is present, so that any secondary Dean vortices that may occur can be avoided or at least reduced.The first rectifier unit preferably has a preferably square central section in which the plurality of bores are arranged. The bores are preferably arranged such that they are arranged along rows running parallel to one another and along columns running perpendicular to the rows and parallel to one another. This arrangement of the bores has led to particularly optimal flow behavior. The number of bores along each row is preferably identical, whereby particularly uniform flow behavior can be achieved. Furthermore, the number of bores along each column is preferably identical, whereby particularly uniform flow behavior can also be achieved. The first rectifier unit preferably has an edge region which preferably runs circumferentially around the preferably square central section.In the edge region, fastening holes are preferably provided, by means of which the first rectifier unit can be attached to a preferably circumferential flange section of the housing by means of connecting elements, such as preferably screws or rivets.

[0024] In one embodiment, the diffuser device comprises a second rectifier unit extending perpendicular to the flow direction and arranged downstream of the subdivision unit, as viewed along the flow direction. The fact that the second rectifier unit extends perpendicular to the flow direction ensures that the air flow impinges perpendicularly on the second rectifier unit. Because the second rectifier unit is arranged downstream of the subdivision unit, as viewed along the flow direction, the flow behavior downstream of the subdivision unit can be adjusted using the second rectifier unit.

[0025] The second rectifier unit preferably has a plurality of bores. The plurality of bores in the second rectifier unit ensure that a pressure drop along the flow direction is guaranteed at the second rectifier unit when an air flow is present, thereby further uniforming the flow behavior. The diameters of the bores in the second rectifier unit are preferably identical, which ensures particularly uniform flow behavior. The second rectifier unit preferably has a central section that extends along a plane extending perpendicular to the flow direction. The fact that the central section extends along the plane extending perpendicular to the flow direction ensures that the air flow hits the central section perpendicularly.The second rectifier unit preferably has a first edge section on a first side of the central section and preferably a second edge section on a second side of the central section opposite the first side. The first edge section and the second edge section are preferably shaped such that they are optimally adapted to the shape of further components of the device. The first edge section is preferably connected to the central section and preferably extends along a second plane on a side of the plane extending perpendicular to the flow direction that is arranged opposite to the flow direction. The second edge section is preferably connected to the central section and preferably extends along a third plane on a side of the plane extending perpendicular to the flow direction that is arranged opposite to the flow direction.The second plane and / or the third plane preferably intersect the plane extending perpendicular to the flow direction. The central section preferably has a first part of the plurality of bores, the first edge section preferably has a second part of the plurality of bores, and the second edge section preferably has a third part of the plurality of bores. With the aid of the first edge section designed as described and / or the second edge section designed as described, it is ensured that the air flow is optimally prepared for a cylindrically shaped component arranged downstream of the diffuser device. The second rectifier unit designed in this way can preferably also be referred to as being cranked at the top and bottom, wherein the first edge section forms a first cranked region and the second edge section forms a second cranked region.The holes in the central section, the holes in the first edge section, and the holes in the second edge section are preferably each arranged such that they are arranged along mutually parallel rows and along columns perpendicular to the rows and parallel to each other. This arrangement of the holes has led to particularly optimal flow behavior.

[0026] The second rectifier unit preferably does not have an edge region having fastening bores, so that in the second rectifier unit a particularly large area can be provided for the plurality of bores compared to an embodiment in which a corresponding edge region is provided. Projections are preferably provided on a guide plate, wherein each projection of the projections extends in the flow direction away from the corresponding guide plate and towards a distal end in which a bore is provided. Preferably, each projection, in an assembled state, projects through a corresponding bore of the plurality of bores in the second rectifier unit, preferably the bores in the central section, such that the bores of the distal ends of the projections are exposed on a side of the second rectifier unit opposite the corresponding guide plate.In order to fasten the second rectifier unit to the subdivision unit, the diffuser device preferably has fastening means, which are preferably designed as fastening clips. In the assembled state, a straight section of each fastening clip preferably extends through a corresponding bore of a corresponding distal end, such that the subdivision unit and the second rectifier unit are secured against relative movement to one another, viewed in the flow direction. A curved section of each fastening clip preferably bears against two opposite sides of a corresponding distal end, such that the fastening clips are secured against slipping out of the corresponding bores in the distal ends, viewed perpendicular to the flow direction.Using the mounting clips and the holes in the distal ends, the subdivision unit and the second rectifier unit can be detachably connected to each other. Due to the detachable connection, the subdivision unit and the second rectifier unit can be easily disassembled and cleaned outside the device using suitable cleaning methods in case of particle contamination.

[0027] According to a second aspect of the invention, the stated object is achieved by a device having the features of patent claim 10. The device is designed for determining particle emissions from brakes. The device has a diffuser device according to the first aspect and a test specimen housing. The diffuser device is arranged upstream of the test specimen housing, as viewed along the flow direction. Because the diffuser device is arranged upstream of the test specimen housing, as viewed along the flow direction, the air flow at the test specimen housing can be optimally adjusted with the aid of the diffuser device. The features, technical effects, and / or advantages described in connection with the diffuser device according to the first aspect of the invention also apply at least analogously to the device according to the second aspect of the invention, so that a corresponding repetition is omitted here.

[0028] The diffuser device and the device can provide a rapid cross-sectional expansion in the diffuser device, while at the same time allowing the flow to follow the diffuser contour at the volume flows required for brake testing. Furthermore, the diffuser device and the device prevent pronounced core flow, flow separation in the edge regions, and the formation of dead water zones, or at least significantly reduce the likelihood of these phenomena occurring. Furthermore, the diffuser device and the device can prevent large-scale vortex formation and thus backflow within the test specimen enclosure. Furthermore, the diffuser device and the device ensure a uniform flow around the brake under test. This allows the particles to be removed from the brake over a large area and not just at specific points.The reproducibility of the flow conditions in the test specimen enclosure and thus the measurement accuracy are increased. Measurement errors caused by particle deposits in the test specimen enclosure are reduced. Thus, the diffuser device and the device ensure high reproducibility of the particle measurement and reduced particle deposition on the walls of the test specimen enclosure. The device is preferably configured so that the air duct upstream of the diffuser device is operated at positive pressure, which reduces measurement errors caused by background concentration.

[0029] Further features, advantages, and possible applications of the present invention will become apparent from the following description of the exemplary embodiments and the figures. All described and / or illustrated features, individually and in any combination, constitute the subject matter of the invention, regardless of their composition in the individual claims or their references. In the figures, the same reference numerals continue to represent the same or similar objects.

[0030] Figures 1 and 2 each show a schematic representation of an embodiment of a diffuser device according to the invention and Figure 3 shows a schematic representation of an embodiment of a device according to the invention with a diffuser device shown in Figures 1 and 2.

[0031] Figures 1 and 2 each show a schematic representation of an embodiment of a diffuser device 1 according to the invention, and Figure 3 shows a schematic representation of an embodiment of a device 3 according to the invention with a diffuser device 1 shown in Figures 1 and 2. The diffuser device 1 is configured for the device 3. The device 3 is configured to determine particle emissions from brakes and can also be referred to as a brake particle test bench or as a section of a brake particle test bench. With the help of the diffuser device 1, the air flow at the device 3 can be optimized. The diffuser device 1 shown in Figures 1 and 2 will be discussed first, followed by the device 3 shown in Figure 3.

[0032] The diffuser device 1 comprises a housing 5 and a subdivision unit 7 shown in Figure 1. The housing 5 extends along a flow direction 9. The flow direction 9 is defined by a direction along which an air flow is guided through the diffuser device 1 incorporated into the device 3 when measuring brake particulate emissions. Because the housing 5 extends along the flow direction 9, the housing 5 limits the air flow at least along a portion of the path traveled by the air flow when measuring particulate emissions.If, in connection with the present invention, a component of the diffuser device 1 or device 3 extends along the flow direction 9, this is to be understood as meaning that the component extends from a corresponding first end to a corresponding second end, wherein the first end is arranged in a first plane extending perpendicular to the flow direction 9 and the second end is arranged in a second plane extending perpendicular to the flow direction 9 and, viewed along the flow direction 9, the first plane is first passed by the air flow moving along the flow direction 9 and the second plane is then passed by the air flow.

[0033] In addition, the housing 5 defines an interior space 11 that widens along the flow direction 9. Because the housing 5 defines the interior space 11 that widens along the flow direction 9, the housing 5 ensures that the flow cross-section widens along the flow direction 9. In the exemplary embodiment of the diffuser device 1 shown in Figures 1 and 2, the housing 5 is configured such that the interior space 11 continuously widens along the flow direction 9, which ensures particularly optimal air guidance. A continuous widening of the interior space 11 is ensured in that the housing 5 has an inner wall facing the interior space 11, which is designed such that the area defined by the inner wall and lying in a plane arranged perpendicular to the flow direction 9 continuously increases in the flow direction 9.

[0034] In addition, the housing 5 separates the interior 11 from an environment 13 of the diffuser device 1, viewed perpendicular to the flow direction 9. The fact that the housing 5 separates the interior 11 from the environment 13 of the diffuser device 1, viewed perpendicular to the flow direction 9, ensures that no particles from the interior 11 enter the environment 13 in the area of ​​the housing 5 and that likewise no particles from the environment 13 enter the interior 11, so that particularly precise measurement results can be determined with the brake particle test bench in which the diffuser device 1 is installed.

[0035] The subdivision unit 7 also extends along the flow direction 9. Because the subdivision unit 7 extends along the flow direction 9, the subdivision unit 7 limits the air flow at least along a portion of the path traveled by the air flow when measuring particle emissions and can thus contribute to optimizing the air flow at the device 3. Furthermore, the subdivision unit 7 divides the interior space 11 perpendicular to the flow direction 9 into a plurality of sections, each section 15 of the plurality of sections being visible at least in part in Figure 1.The fact that the subdivision unit 7 divides the interior space 11 into a plurality of sections perpendicular to the flow direction 9 ensures that the air flow flowing through the diffuser device 1 is divided into a plurality of air flow sections as seen perpendicular to the flow direction 9, whereby the flow behavior of these air flow sections can be specifically influenced and optimized. The subdivision unit 7 is designed such that the plurality of sections of the interior space 11 expand along the flow direction 9. The fact that the subdivision unit 7 is designed such that the plurality of sections of the interior space 11 expand along the flow direction 9 ensures that the subdivision unit 7 ensures that each flow cross-section of each air flow section expands along the flow direction 9.In the exemplary embodiment of the diffuser device 1 shown in Figures 1 and 2, the subdivision unit 7 is configured such that the multiple sections of the interior space 11 continuously expand along the flow direction 9, which ensures particularly optimal air flow. Continuous expansion of the multiple sections of the interior space 11 is ensured by the fact that the subdivision unit 7 has a plurality of walls designed such that the surfaces defined by the walls and arranged in a plane perpendicular to the flow direction 9 continuously increase in the flow direction 9.

[0036] The subdivision unit 7 of the exemplary embodiment of the diffuser device 1 shown in Figures 1 and 2 can also be referred to as a guide plate unit or a guide plate insert. With the help of the subdivision unit 7, flat sections can be provided along which the air flow flows, whereby turbulence in the air flow can be avoided or at least significantly reduced. The subdivision unit 7 has a plurality of guide plates extending along the flow direction 9, which are spaced apart from one another perpendicular to the flow direction 9 and which divide the interior space 11 into the plurality of sections perpendicular to the flow direction 9. In Figure 1, each guide plate 17 is shown at least in section.Because the subdivision unit 7 has a plurality of guide vanes extending along the flow direction 9, which are spaced apart from one another perpendicular to the flow direction 9 and which divide the interior space 11 into a plurality of sections perpendicular to the flow direction 9, backflows, i.e. a movement of air flows counter to the flow direction 9, can be prevented or at least the likelihood of their occurrence can be significantly reduced. Furthermore, because the subdivision unit 7 has a plurality of guide vanes extending along the flow direction 9, which are spaced apart from one another perpendicular to the flow direction 9 and which divide the interior space 11 into a plurality of sections perpendicular to the flow direction 9, large-scale vortices within the diffuser device 1 can be prevented or at least the likelihood of their occurrence can be significantly reduced.

[0037] In the exemplary embodiment of the diffuser device 1 shown in Figures 1 and 2, four guide vanes are provided. However, the present invention is not limited to four guide vanes; rather, just one guide vane 17, two guide vanes, three guide vanes, or more than four guide vanes can also be provided. The subdivision unit 7 can therefore also have just one guide vane 17 extending along the flow direction 9, which divides the interior 11 into the multiple sections perpendicular to the flow direction 9. This makes it possible to provide a particularly material-friendly alternative. This just one guide vane 17 can, for example, be one of the guide vanes 17 shown in Figure 1.The four guide vanes shown in Figure 1 divide the interior space 11 into five sections perpendicular to the flow direction 9, whereby with a correspondingly different number of guide vanes, a different number of sections of the multiple sections of the interior space 11 can also be provided.

[0038] The guide plate 17, which is arranged radially inward with respect to a straight line along which the arrow symbolizing the flow direction 9 extends, can also be referred to as the first guide plate. The guide plate 17, which is arranged next around the first guide plate with respect to the straight line in the radial direction, can also be referred to as the second guide plate. The guide plate 17, which is arranged next around the second guide plate with respect to the straight line in the radial direction, can also be referred to as the third guide plate. The guide plate 17, which is arranged next around the third guide plate with respect to the straight line in the radial direction, can also be referred to as the fourth guide plate. The first guide plate defines a first section of the interior 11, the first section being the section 15 of the interior 11 that is arranged radially inward with respect to the straight line.The first guide plate together with the second guide plate defines a second section of the interior 11, the second section being the section 15 of the interior 11 which is arranged next around the first section with respect to the straight line in the radial direction. The second guide plate together with the third guide plate defines a third section of the interior 11, the third section being the section 15 of the interior 11 which is arranged next around the second section with respect to the straight line in the radial direction. The third guide plate together with the fourth guide plate defines a fourth section of the interior 11, the fourth section being the section 15 of the interior 11 which is arranged next around the third section with respect to the straight line in the radial direction.The fourth guide plate defines together with the housing 5, specifically with the inner wall of the housing 5 facing the interior space 11, a fifth section of the interior space 11, wherein the fifth section is the section 15 of the interior space 11 which is arranged next around the fourth section with respect to the straight line in the radial direction.

[0039] Each guide plate 17 of the guide plates is shaped and arranged such that the distances between the guide plates increase along the flow direction 9 such that each section 15 of the interior space 11 continuously widens along the flow direction 9. The first guide plate is therefore shaped and arranged such that the first section of the interior space 11 continuously widens along the flow direction 9. The first guide plate and the second guide plate are shaped and arranged such that the second section of the interior space 11 continuously widens along the flow direction 9. The second guide plate and the third guide plate are shaped and arranged such that the third section of the interior space 11 continuously widens along the flow direction 9. The third guide plate and the fourth guide plate are shaped and arranged such that the fourth section of the interior space 11 continuously widens along the flow direction 9.The fourth guide plate and the housing 5 are shaped and arranged such that the fifth section of the interior space 11 continuously expands along the flow direction 9. Because each section 15 of the interior space 11 continuously expands along the flow direction 9, a particularly advantageous flow profile is achieved.

[0040] Each guide plate 17 of the guide plates has a rectangular, in particular square, circumferential cross-sectional area that extends along a plane arranged perpendicular to the flow direction 9. A rectangular, in particular square, circumferential cross-sectional area can also be referred to as a rectangular, in particular square, and hollow cross-sectional area. The rectangular, in particular square, cross-sectional area of ​​each guide plate 17 encircles the straight line along which the arrow extends, symbolizing the flow direction 9.Because each guide plate 17 of the guide plates has a rectangular, in particular square, circumferential cross-sectional area extending along a plane arranged perpendicular to the flow direction 9, at least some air flow sections can be guided by the diffuser device 1 in such a way that, viewed along the flow direction 9, they also assume a rectangular, in particular square, and circumferential shape, at least in sections. A rectangular, in particular square, and circumferential shape of at least some air flow sections has led to particularly optimal flow behavior in a test specimen housing 47 (see Figure 3) downstream of the diffuser device 1 in the flow direction 9.In the embodiment of the diffuser device 1 shown in Figures 1 and 2, each guide plate 17 of the guide plates has a rectangular, in particular square, circumferential cross-sectional area along the entire extent of the corresponding guide plate 17 along the flow direction 9, which extends along a corresponding plane arranged perpendicular to the flow direction 9, whereby a particularly optimal flow behavior can be achieved in the test specimen housing 47. The special case of the square circumferential cross-sectional area has led to particularly optimal flow conditions.The guide vanes are rectangular in shape and arranged relative to one another in such a way that a first straight line of two straight lines lying in a plane perpendicular to the flow direction 9 and intersecting in the straight line along which the arrow symbolizing the flow direction 9 extends intersects two opposite corner points of each guide vane 17, and a second straight line of the two straight lines intersects the other two, likewise opposite, corner points of each guide vane 17. This results in particularly optimal flow behavior.In the embodiment of the diffuser device 1 shown in Figures 1 and 2, each guide plate 17 has a square cross-sectional area, and the two straight lines lying in the plane perpendicular to the flow direction 9 and intersecting in the line along which the arrow symbolizing the flow direction 9 extends form a right angle. This results in particularly optimal flow behavior.

[0041] The guide vanes are rectangular in shape and arranged relative to one another along the entire extent of each corresponding guide vane 17 along the flow direction 9 in such a way that a first straight line of two straight lines lying in a plane perpendicular to the flow direction 9 and intersecting in the straight line along which the arrow symbolizing the flow direction 9 extends intersects two opposite corner points of each guide vane 17, and a second straight line of the two straight lines intersects the other two likewise opposite corner points of each guide vane 17. This results in particularly optimal flow behavior along the entire extent of the guide vanes along the flow direction 9.In the embodiment of the diffuser device 1 shown in Figures 1 and 2, each guide plate 17 is square along the entire extent of the corresponding guide plate 17 along the flow direction 9, and the two straight lines that lie in the plane perpendicular to the flow direction 9 and intersect in the straight line along which the arrow symbolizing the flow direction 9 extends form a right angle. This results in particularly optimal flow behavior along the entire extent of the corresponding guide plate 17 along the flow direction 9.

[0042] Viewed perpendicular to the flow direction 9, the guide vanes are spaced apart from one another, so that the sections of the interior space 11 are formed between the guide vanes. The guide vanes are spaced apart from one another such that the distance between two adjacent guide vanes perpendicular to the flow direction 9 corresponds to the distances between the other adjacent guide vanes perpendicular to the flow direction 9. The distances between adjacent guide vanes perpendicular to the flow direction 9 are therefore identical for all guide vanes. Because the distances between adjacent guide vanes perpendicular to the flow direction 9 are identical for all guide vanes, a particularly uniform flow behavior can be provided, particularly as viewed in the flow direction 9 downstream of the diffuser device 1.

[0043] Furthermore, the diffuser device 1 has a first rectifier unit 19, which in the illustrated embodiment is designed as a rectifier plate, and a second rectifier unit 21, which in the illustrated embodiment is also designed as a rectifier plate. The first rectifier unit 19 extends perpendicular to the flow direction 9 and is arranged upstream of the subdivision unit 7 as viewed along the flow direction 9. The fact that the first rectifier unit 19 extends perpendicular to the flow direction 9 ensures that the air flow strikes the first rectifier unit 19 perpendicularly. The fact that the first rectifier unit 19 is arranged upstream of the subdivision unit 7 as viewed along the flow direction 9 means that the flow behavior upstream of the subdivision unit 7 can be adjusted using the first rectifier unit 19.The second rectifier unit 21 also extends perpendicular to the flow direction 9 and, as viewed along the flow direction 9, is arranged downstream of the subdivision unit 7. The fact that the second rectifier unit 21 extends perpendicular to the flow direction 9 ensures that the air flow hits the second rectifier unit 21 perpendicularly. The fact that the second rectifier unit 21 is arranged downstream of the subdivision unit 7 as viewed along the flow direction 9, the flow behavior downstream of the subdivision unit 7 can be adjusted with the help of the second rectifier unit 21. The fact that the first rectifier unit 19 is designed as a rectifier plate and the second rectifier unit 21 is also designed as a rectifier plate, the diffuser device 1 can be designed to be particularly compact as viewed along the flow direction 9.

[0044] The first rectifier unit 19 has a plurality of bores. The bores ensure that, within the air flow directed along the flow direction 9, regions with a high speed are decelerated and regions with a low speed are accelerated. For this purpose, the bores have different diameters, wherein the diameters of the bores can be adapted to the geometry of the other sections of the device 3 and in particular of the diffuser device 1. Furthermore, the bores ensure that a pressure drop along the flow direction 9 at the first rectifier unit 19 is guaranteed when an air flow is present, so that any secondary Dean vortices that may occur can be avoided or at least reduced. The first rectifier unit 19 has a square central section in which the plurality of bores are arranged.The holes are arranged so that they run along rows that run parallel to one another and along columns that run perpendicular to the rows and parallel to one another. This arrangement of the holes has led to particularly optimal flow behavior. The number of holes along each row is identical, which allows particularly uniform flow behavior to be achieved. Furthermore, the number of holes along each column is identical, which also allows particularly uniform flow behavior to be achieved. The first rectifier unit 19 has an edge region 23 that runs circumferentially around the square central section. Mounting holes are provided in the edge region 23, with the aid of which the first rectifier unit 19 can be attached to a circumferential flange section 25 of the housing 5 using connecting elements such as screws or rivets, as shown in Figure 2.The second rectifier unit 21 also has a plurality of bores. The plurality of bores in the second rectifier unit 21 ensure that a pressure drop along the flow direction 9 is guaranteed at the second rectifier unit 21 when an air flow is present, thereby further uniforming the flow behavior. The diameters of the bores in the second rectifier unit 21 are identical, which ensures particularly uniform flow behavior. The second rectifier unit 21 has a central section 27 which extends along a plane extending perpendicular to the flow direction 9. The fact that the central section 27 extends along the plane extending perpendicular to the flow direction 9 ensures that the air flow hits the central section 27 perpendicularly.

[0045] The second rectifier unit 21 has a first edge section 29 on a first side of the central section 27 and a second edge section 31 on a second side of the central section 27 opposite the first side. The first edge section 29 and the second edge section 31 can be shaped such that they are optimally adapted to the shape of further components of the device 3. The first edge section 29 is connected to the central section 27 and extends along a second plane on a side arranged opposite the flow direction 9 of the plane extending perpendicular to the flow direction 9. The second edge section 31 is connected to the central section 27 and extends along a third plane on a side arranged opposite the flow direction 9 of the plane extending perpendicular to the flow direction 9.The second plane and the third plane intersect the plane extending perpendicular to the flow direction 9. The central section 27 has a first part of the plurality of bores, the first edge section 29 has a second part of the plurality of bores, and the second edge section 31 has a third part of the plurality of bores. With the help of the first edge section 29 and the second edge section 31 designed as described, it is ensured that the air flow is optimally prepared for a cylindrically shaped component arranged downstream of the diffuser device 1. The second rectifier unit 21 can also be referred to as being cranked at the top and bottom, with the first edge section 29 forming a first cranked region and the second edge section 31 forming a second cranked region.The holes in the central section 27, the holes in the first edge section 29, and the holes in the second edge section 31 are each arranged along parallel rows and along columns perpendicular to the rows and parallel to each other. This arrangement of the holes has led to particularly optimal flow behavior.

[0046] The second rectifier unit 21 does not have an edge region with fastening bores, so that in the second rectifier unit 21 a particularly large area can be provided for the plurality of bores compared to an embodiment in which a corresponding edge region is provided. Instead, projections are provided on the fourth guide plate, wherein each projection 33 of the projections extends in the flow direction 9 away from the fourth guide plate and towards a distal end 35 in which a bore is provided. In the assembled state shown in Figure 2, each projection 33 projects through a corresponding bore of the plurality of bores in the second rectifier unit 21, specifically the bores in the central section 27, such that the bores of the distal ends of the projections 33 are exposed on a side of the second rectifier unit 21 opposite the fourth guide plate.In order to fasten the second rectifier unit 21 to the subdivision unit 7, the diffuser device 1 has fastening means which, in the embodiment shown in Figures 1 and 2, are designed as fastening clips. In the assembled state, a straight section of each fastening clip 37 extends through a corresponding bore of a corresponding distal end 35, so that the subdivision unit 7 and the second rectifier unit 21 are secured against relative movement to one another as viewed in the flow direction 9. A curved section of each fastening clip 37 rests on two opposite sides of a corresponding distal end 35, so that the fastening clips are secured against slipping out of the corresponding bores in the distal ends as viewed perpendicular to the flow direction 9.Using the fastening clips and the holes in the distal ends, the subdivision unit 7 and the second rectifier unit 21 can be detachably connected to each other. Due to the detachable connection, the subdivision unit 7 and the second rectifier unit 21 can be easily disassembled and cleaned outside the device 3 using suitable cleaning methods in case of any particle contamination.

[0047] The housing 5 has first connecting means and the subdivision unit 7 has second connecting means. The housing 5 and the subdivision unit 7 can be detachably connected to one another using the first connecting means and second connecting means. Due to the detachable connection, the housing 5 and the subdivision unit 7 can be easily disassembled and, in the event of any particle contamination, cleaned using suitable cleaning methods outside the device 3. Figure 1 shows two of the second connecting means, each of the two second connecting means being designed as a flange section 39. Each flange section 39 has a first section that extends perpendicularly away from the fourth guide plate and a second section that extends perpendicularly away from the first section and parallel to a section of the fourth guide plate.Each flange section 39 has an elongated hole open on one side in its second section. The two flange sections shown in Figure 1 are spaced apart from each other in the flow direction 9. The first sections of the flange sections extend along the same plane, and the second sections of the flange sections extend along a second plane perpendicular to this plane. The elongated holes are thus arranged in the second plane.In the flange section 39 arranged against the flow direction 9, the elongated hole is open against the flow direction 9, so that the subdivision unit 7 can be brought into the housing 5 against the flow direction 9 and a projection extending from the housing 5 in the direction of the straight line along which the arrow runs, which symbolizes the flow direction 9, can be brought into the elongated hole via the open section of the elongated hole, so that this projection, together with the second section of the flange section 39, in the assembled state, prevents a relative movement between the housing 5 and the subdivision unit 7 perpendicular to the flow direction 9, namely up and down in Figure 1.In the flange section 39 arranged in the flow direction 9, the elongated hole is open perpendicular to the flow direction 9, specifically downwards in Figure 1, so that the subdivision unit 7 can be brought into the housing 5 by tilting relative to the housing 5 and a movement counter to the flow direction 9, and a projection extending from the housing 5 in the direction of the straight line along which the arrow runs, which symbolizes the flow direction 9, can be brought into the elongated hole via the opened section of the elongated hole, so that this projection, together with the second section of the flange section 39, in the assembled state, prevents a relative movement between the housing 5 and the subdivision unit 7 along the flow direction 9, specifically to the left and right in Figure 1.In Figure 1, only two flange sections are shown, but, similar to the case with the projections 33, two correspondingly designed flange sections are also provided on the opposite side of the subdivision unit 7, so that a mechanically robust but detachable connection can be provided between the housing 5 and the subdivision unit 7.

[0048] As already described, the device 3 shown in Figure 3 has the diffuser device 1 shown in Figures 1 and 2. The device 3 is configured to determine particle emissions from brakes. In addition to the diffuser device 1, the device 3 has a first straight pipe section 41, a pipe bend 43 with integrated guide vanes attached to the first straight pipe section 41, a second straight pipe section 45 attached to the pipe bend 43, the diffuser device 1 attached to the second straight pipe section 45, a test specimen housing 47 attached to the diffuser device 1, and a nozzle device 49 attached to the test specimen housing 47. Filtered air is guided to the diffuser device 1 via the first straight pipe section 41, the pipe bend 43, and the second straight pipe section 45. In the diffuser device 1, the cross section is widened along the flow direction 9 towards the test specimen housing 47.The diffuser device 1 is arranged in front of the test specimen housing 47, as seen along the flow direction 9, so that the flow conditions in the test specimen housing 47 can be optimized with the help of the diffuser device 1. A brake to be tested is mounted in the center of the test specimen housing 47 and driven by a shaft that passes through the rear and is not shown in Figure 3. The particles are collected in the nozzle device 49, the air volume flow is accelerated, and directed toward a measuring tunnel of the device 3.

[0049] During operation of the device 3, a velocity profile that is unevenly distributed across the cross-section may occur due to components of the device 3 arranged upstream of the diffuser device 1, as seen along the flow direction 9, and / or due to the cross-sectional expansion from the second straight pipe section 45 toward the test specimen housing 47. The bores of the first rectifier unit 19, in particular the bore distribution and / or bore sizes, are designed such that excessive velocity peaks are slowed down and slow velocity ranges are accelerated. Likewise, if secondary Dean vortices are generated in the pipe bend 43, these are reduced by a high pressure drop across the first rectifier unit 19. The subdivision unit 7 forces an expansion of the flow profile, with the multiple baffle subdivisions preventing backflows and large-scale vortices within the diffuser device 1.The second rectifier unit 21 at the outlet of the diffuser device 1 ensures a further pressure drop, which evens out the flow behavior. To follow the cylindrical shape of the test specimen housing 47, the second rectifier unit 21 is designed with a cranked top and bottom. This reduces dead water areas in the test specimen housing 47.

[0050] With the help of the diffuser device 1, a flow profile that is homogeneous in magnitude and direction is achieved in the test specimen housing 47. In particular, this is demonstrated on a vertical plane that is tangential to the brake disc and touches the point on the brake disc when the flow approaches the brake disc, which can also be referred to as the stagnation point. The vertical plane is therefore located in front of a mounted brake disc, viewed along the flow direction 9. As already described, both the second rectifier unit 21 and the subdivision unit 7 can be easily dismantled and, in the event of any particle contamination, cleaned using suitable cleaning methods outside the device 3. The diffuser device 1 represents a flow restriction that results in a pressure loss.The device 3 is therefore preferably configured such that when testing a brake and with the corresponding air flow, the pressure upstream of the diffuser device 1 is higher than the pressure downstream of the diffuser device 1. The device 3 is preferably configured such that a slight negative pressure is set within the test specimen housing 47, i.e. the pressure in the test specimen housing 47 is lower than the pressure in the environment 13. The relative pressure at the pipe guide, i.e. at the first straight pipe section 41, at the pipe bend 43 and at the second straight pipe section 45, can nevertheless be positive due to the pressure loss in the diffuser device 1 and any leaks in this area do not lead to an increase in the background concentration since no external air enters the system from outside.Preferably, the device 3 is configured such that an overpressure is set within the first straight pipe section 41, the pipe bend 43 and the second straight pipe section 45, ie the pressure in the first straight pipe section 41, in the pipe bend 43 and in the second straight pipe section 45 is greater than the pressure in the environment 13, whereby measurement errors due to background concentration are reduced.

[0051] Preferably, all internal components, in particular all components of the diffuser device 1, such as the housing 5, the subdivision unit 7, the first rectifier unit 19, the second rectifier unit 21, each projection 33, each fastening clamp 37, each flange section 39, as well as the first straight pipe section 41, the pipe bend 43, the second straight pipe section 45, the test specimen housing 47 and the nozzle device 49 are electrically conductively connected to a grounded component of the device 3, such as a grounded pipe guide, in order to prevent electrostatic effects and the associated particle deposition.

[0052] By configuring the bore distribution and size within the first rectifier unit 19 and the second rectifier unit 21, customized flow profiles can be generated in the test specimen housing 47. For example, a velocity increase is provided in peripheral areas to reduce possible particle deposits on the walls of the test specimen housing 47 and the nozzle device 49. Furthermore, the degree of turbulence can be controlled in the same way.

[0053] In the illustrated embodiment of the diffuser device 1, the first rectifier unit 19 and the second rectifier unit 21 are each designed as a rectifier plate with a plurality of bores. Alternatively, the first rectifier unit 19 and / or the second rectifier unit 21 can each be designed as a flow straightener with a honeycomb structure or as a tube bundle. In the illustrated embodiment of the diffuser device 1, the subdivision unit 7 has a plurality of guide plates extending along the flow direction 9. Instead of the selected form of the subdivision unit 7 as a guide plate insert, the subdivision unit 7 can also have airfoil profiles, porous structures and / or fills.Alternatively, the subdivision unit 7 can also have a diffuser grid with multiple horizontal and vertical subdivisions extending from a first section of the diffuser device 1, at which a diffuser inlet is provided and from which the diffuser device 1 extends along the flow direction 9 towards a second section, towards the second section at which a diffuser outlet is provided.

[0054] Particularly preferably, the internals, in particular all components of the diffuser device 1, such as the housing 5, the subdivision unit 7, the first rectifier unit 19, the second rectifier unit 21, each projection 33, each fastening clamp 37, each flange section 39, as well as the first straight pipe section 41, the pipe bend 43, the second straight pipe section 45, the test specimen housing 47 and the nozzle device 49, are designed to be mechanically robust, so that the internals take on the function of a retention capacity, so that if, for example, the brake disc bursts during testing of a brake, the walls of the device 3 do not allow parts of the brake disc to escape from the test stand.Preferably, the components of the diffuser device 1 and the components of the device 3 are designed such that, in the event of a brake disc breaking, they can withstand the centrifugal force of the torn-off part of the brake disc, so that this part cannot injure persons nearby. Preferably, each component has an impact strength that is equal to or greater than a predetermined minimum impact strength. Preferably, the device 3 has a particle generator or a device for introducing test dust. Preferably, the particle generator or the device for introducing test dust is attached to a component of the device 3, in particular to a component of the diffuser device 1. Thus, a defined quantity of particles or dust can be introduced into the device 3 and detected, and the device 3 can be evaluated or tested based on the detection.

[0055] Additionally, it should be noted that "comprising" does not exclude other elements or steps, and "a" or "an" does not exclude a plurality. Furthermore, it should be noted that features described with reference to one of the above embodiments can also be used in combination with other features of other embodiments described above. Reference signs in the claims are not to be considered as limitations.

[0056] Reference symbol

[0057] Diffuser device

[0058] device

[0059] Housing

[0060] subdivision unit

[0061] Flow direction

[0062] Interior

[0063] Vicinity

[0064] Section of the interior

[0065] guide plate first rectifier unit second rectifier unit

[0066] peripheral area

[0067] Flange section

[0068] central section first edge section second edge section

[0069] Protrusion distal end of the protrusion

[0070] Mounting clip

[0071] Flange section first straight pipe section

[0072] Pipe bend second straight pipe section

[0073] Test specimen enclosure

[0074] Nozzle device

Claims

Patent claims 1. Diffuser device (1) for a device (3) for determining particle emissions from brakes, wherein the diffuser device (1) has a housing (5) extending along a flow direction (9), which defines an interior space (11) widening along the flow direction (9) and separating the interior space (11) from an environment (13) of the diffuser device (1) perpendicular to the flow direction (9), and a subdivision unit (7) extending along the flow direction (9) and subdividing the interior space (11) perpendicular to the flow direction (9) into a plurality of sections.

2. Diffuser device (1) according to the preceding claim, wherein the subdivision unit (7) is designed such that the plurality of sections of the interior space (11) widen along the flow direction (9).

3. Diffuser device (1) according to one of the preceding claims, wherein the housing (5) has first connecting means and the subdivision unit (7) has second connecting means, wherein the housing (5) and the subdivision unit (7) can be detachably connected to one another by means of the first connecting means and second connecting means.

4. Diffuser device (1) according to one of the preceding claims, wherein the subdivision unit (7) has a guide plate (17) extending along the flow direction (9) which divides the interior space (11) into the plurality of sections perpendicular to the flow direction (9).

5. Diffuser device (1) according to one of the preceding claims, wherein the subdivision unit (7) has a plurality of guide plates extending along the flow direction (9), which are spaced apart from one another perpendicular to the flow direction (9) and which divide the interior space (11) perpendicular to the flow direction (9) into the plurality of sections.

6. Diffuser device (1) according to claim 5, wherein each guide plate (17) of the guide plates has a rectangular circumferential cross-sectional area which extends along a plane arranged perpendicular to the flow direction (9).

7. Diffuser device (1) according to one of claims 5 or 6, wherein the guide plates are rectangular and arranged relative to one another in such a way that a first straight line of two straight lines lying in a plane perpendicular to the flow direction (9) and intersecting in a straight line along which the flow direction (9) runs intersects two opposite corner points of each guide plate (17) and a second straight line of the two straight lines intersects the other two likewise opposite corner points of each guide plate (17).

8. Diffuser device (1) according to one of the preceding claims, which has a first rectifier unit (19) extending perpendicular to the flow direction (9) and which is arranged in front of the subdivision unit (7) as seen along the flow direction (9).

9. Diffuser device (1) according to one of the preceding claims, which has a second rectifier unit (21) extending perpendicular to the flow direction (9) and arranged after the subdivision unit (7) as seen along the flow direction (9).

10. Device (3) for determining particle emissions from brakes, wherein the device (3) comprises a diffuser device (1) according to one of the preceding claims and a test specimen housing (47), wherein the diffuser device (1) is arranged in front of the test specimen housing (47) as seen along the flow direction (9).

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