Test bench arrangement for determining tire and / or brake wear

Abstract

According to the invention, in order to allow more realistic conditions for carrying out a tire or brake abrasion test using a test bench arrangement, the supply air line (11) has a longitudinal axis (Lzu) when opening into the housing interior (3), and the longitudinal axis (Lzu) is located below a plane (E) which runs through the tire rotational axis (7) and which is parallel to a tangent (T) through the highest point (O) of the part of the test bench roller (5) in the housing interior (3) projecting into the housing interior (3).

Description

[0001] Test bench setup for determining tire and / or brake wear

[0002] The present invention relates to a test bench arrangement, in particular for determining tire and / or brake wear, wherein the test bench arrangement has at least one enclosure defining an interior space, wherein an air supply line for supplying air into the interior space and an exhaust air line for removing exhaust air from the interior space are arranged on the enclosure, wherein the exhaust air line is connected or connectable to at least one wear measuring device, and wherein at least one test bench roller rotatably mounted about a roller pivot axis is provided in the test bench arrangement, which projects at least partially into the interior space of the enclosure through a roller recess on an enclosure floor.and when carrying out a test run with the test stand arrangement in the enclosure interior, at least one tire to be tested can be arranged to rotate about a tire rotation axis, and the tire to be tested rolls with a tire tread on a roller tread of at least one test stand roller, and the tire tread makes contact with the test stand roller at a tire contact surface.

[0003] The environmental impact of particulate matter from vehicles has long been known and is subject to increasingly stringent legal regulations. Until now, the focus has primarily been on the particulate matter generated by the combustion process in an internal combustion engine, which is released into the environment via exhaust gases. However, other sources of particulate matter within vehicles have now been identified and are increasingly coming into focus. One example is a vehicle's braking system, which generates particulate matter through the abrasion of brake discs and brake pads during operation. This particulate matter is released into the environment and contributes to airborne particulate matter pollution. Another example of a vehicle's particulate matter source is tires, which produce tire abrasion during vehicle operation, also emitted as particulate matter into the surroundings.However, it has been shown that tire abrasion differs completely from brake abrasion, for example in terms of particle morphology, particle size, particle concentration or particle size distribution.

[0004] To better assess the generation and extent of particulate matter from tire or brake abrasion, it is already known to collect the tire or brake abrasion either during a vehicle journey and subsequently measure specific characteristics of the tire abrasion, such as particle size distribution, particle mass, etc., or to measure the tire or brake abrasion on special test benches. This is described, for example, in Hesse D., et al., “Comparison of Methods for Sampling Particulate Emissions from Tires under Different Test Environments”, Atmosphere 2022, 13, 1262. However, measuring tire or brake abrasion during driving is difficult because there is always cross-contamination with foreign particles from the tire's environment, such as road debris, ambient dust, etc.Foreign particles are introduced into the measuring system along with the abrasion and cannot be separated or distinguished from tire or brake abrasion within the system, or only with great difficulty. This distorts the accuracy of the tire or brake abrasion measurement. Such a measurement is therefore unreliable. In a tire abrasion test rig, a driven tire rolls on a driven roller. The tire is enclosed to collect the tire abrasion particles within the enclosure. The tire abrasion particles are then removed from the enclosure and subjected to measurement, for example, with a particle counter. The problem with such tire abrasion test rigs is that the enclosure and the airflow do not correspond to the actual conditions on a vehicle. This can make it difficult to obtain a realistic measurement of tire abrasion on a tire abrasion test rig.

[0005] It is therefore an object of the present invention to provide a test bench arrangement that enables more realistic conditions for carrying out a tire or brake wear test.

[0006] This problem is solved according to the invention by the fact that the air supply duct has a longitudinal axis at its opening into the interior of the enclosure, and that this longitudinal axis is located below a plane that passes through the tire's axis of rotation and is parallel to a tangent through the highest point of the part of the test rig roller projecting into the interior of the enclosure. This creates flow conditions within the enclosure that more realistically replicate the conditions in a vehicle's wheel well, where the tire is normally located. In particular, an airflow near the ground is generated, as would also occur on a real vehicle.

[0007] The realistic airflow conditions within the enclosure are improved when the supply air duct enters the enclosure via a supply air duct cross-section, and this supply air duct cross-section is located entirely below ground level. This is particularly true when the supply air duct has a supply air duct cross-section at the point of entry into the enclosure, and an imaginary extension of this supply air duct cross-section along the longitudinal axis of the supply air duct into the enclosure runs entirely below ground level within the enclosure.

[0008] To direct the airflow to the point where tire abrasion occurs, it is advantageous if the air intake duct has a cross-sectional area at its entry into the enclosure, and if an imaginary extension of this cross-sectional area along the longitudinal axis of the air intake duct into the enclosure encompasses the highest point of the test rig roller. This measure also helps to realistically simulate the actual airflow conditions in a vehicle's wheel well within the enclosure. This also applies if the imaginary extension of the air intake duct cross-section into the enclosure includes the portion of the tire contact patch that forms during a test run with the test rig setup, where the tire tread comes into contact with the test rig roller as the tire rolls on the roller's tread.This also applies if the supply air fed into the enclosure via the supply air duct is directed towards the tire contact area that forms during a test run with the test bench arrangement.

[0009] Advantageously, the imagined extension of the air supply duct cross-section into the enclosure interior encompasses a portion of the roller tread that, when the tire rolls on the test rig roller, lies in front of the tire's contact patch in the direction of rotation. By supplying air to the test rig roller, any abrasion particles adhering to the roller tread can be loosened and carried away from the enclosure by the airflow. This improves the measurement of abrasion particles because less particle loss occurs.

[0010] If the imaginary extension of the air supply duct cross-section in the direction of the longitudinal axis of the air supply duct into the enclosure interior includes a part of a roller gap between the roller recess and the roller running surface, which, when the tire rolls on the roller running surface of the test bench roller in the direction of rotation of the test bench roller, lies in front of the part of the tire contact area, then the penetration of foreign particles from the environment into the enclosure interior can be reduced.

[0011] A particularly advantageous feature of the test rig is a nozzle arrangement designed to direct purge air onto the test rig roller in the area of ​​a roller gap between the roller recess and the roller running surface, creating a purge air curtain. This purge air curtain reduces the ingress of foreign particles from the environment into the enclosure interior and the escape of abrasion particles from the enclosure interior. The purge air curtain can also dislodge abrasion particles adhering to the roller running surface, thus improving the measurement of abrasion particles.

[0012] The removal of abrasion particles by the airflow can be improved if the supply air duct directs the supply air into the enclosure over a width at least equal to the width of the tire contact patch in the direction of the tire's axis of rotation during a test run with the test bench setup. Similarly, the exhaust air duct discharges the exhaust air from the enclosure over a width at least equal to the width of the tire's contact patch in the direction of the tire's axis of rotation during a test run with the test bench setup.

[0013] Preferably, an air supply fan is provided in the supply air duct of the test rig. During a test run, this fan supplies the air into the enclosure and delivers the air into the enclosure at an overpressure relative to the ambient pressure. This reduces or even prevents the ingress of foreign particles from the environment into the enclosure's interior, thus avoiding any distortion of the measurement of abrasion particles.This can also be achieved if a supply air blower is provided in the supply air duct of the test bench arrangement, which supplies the supply air into the enclosure during a test run with the test bench arrangement, and an exhaust air blower is provided in the exhaust air duct, which removes the exhaust air from the enclosure during a test run with the test bench arrangement, and if the supply air volume flow rate generated by the supply air blower is essentially the same as the exhaust air volume flow rate generated by the exhaust air blower.

[0014] A roller enclosure is particularly advantageous, being designed adjoining the main enclosure and surrounding the roller at least partially, preferably completely, the test rig roller, except for the portion projecting into the interior of the enclosure. This also ensures effective isolation of the test rig assembly from foreign particles in the environment.

[0015] The present invention is explained in more detail below with reference to Figures 1 to 4, which show exemplary, schematic, and non-limiting advantageous embodiments of the invention.

[0016] Fig. 1 shows a perspective view of an embodiment of a test bench arrangement according to the invention;

[0017] Fig. 2 shows a sectional view of the test rig arrangement according to the invention;

[0018] Fig. 3 shows a partial detail view of the test stand roller and the tire to be tested; and

[0019] Fig. 4 shows a top view of a test rig roller with a sketched tire to be tested.

[0020] Fig. 1 shows an embodiment of the test rig arrangement 1 according to the invention for determining tire and / or brake wear. The test rig arrangement 1 comprises an enclosure 2, which defines an interior space 3. "Defines" means that the enclosure 2 at least partially surrounds the interior space 3, preferably completely, except for a roller recess 4 described later. For this purpose, the enclosure 2 has boundary walls, each boundary wall at least partially defining the interior space 3, as will be explained in more detail below.

[0021] The housing 2 has a roller recess 4 through which a test stand roller 5 projects at least partially into the interior of the housing 3. During a test run with the test stand arrangement 1, a tire 6 to be tested is positioned in the housing 2. The tire 6 rests on the roller running surface 5a of the test stand roller 5 via a tire contact surface 13, thus making contact with the test stand roller 5 at the tire contact surface 13.

[0022] The test stand roller 5 is, for example, as shown in the embodiment of Fig.1, arranged at least partially below a test stand floor 10 and the housing 2 on the test stand floor 10.

[0023] However, it is not necessary for the housing 2 to be arranged in the direction of gravity above the test stand roller 5 and / or for the tire 6 to be arranged in the direction of gravity above the test stand roller 5, as in Fig. 1. In one possible embodiment, this arrangement can also be pivoted by a certain angle, preferably by 90°. In such an arrangement, the housing 2 and / or the tire 6 and the test stand roller 5 would be arranged essentially horizontally next to each other.

[0024] The tire 6 is rotatably mounted in the housing 2 about a tire axis of rotation 7. During a test run with the test stand arrangement 1, the tire 6 can be driven by a tire drive 22 (see Fig. 2), such as an electric motor or an electric motor with gearbox, so that the tire 6 rotates about the tire axis of rotation 7.

[0025] The tire 6 is, for example, rotatably mounted in the housing 2 via a tire holder, with the tire 6 being arranged on the tire holder. For example, the tire is arranged on a tire rim, and the tire rim of the tire 6 is arranged on a rotatably mounted wheel hub as a tire holder. The tire holder, like the wheel hub 6, can be driven by the tire drive 22. The axis of rotation of the rotatably mounted tire holder thus forms the tire axis of rotation 7 (with or without the tire 6 arranged in the housing). Likewise, the test stand roller 5 can be driven by a roller drive 8, such as an electric motor or an electric motor with gearbox, during a test run with the test stand arrangement 1, so that the test stand roller 5 rotates about a roller axis of rotation 9.

[0026] For a test run, it is generally sufficient if either the tire 6 or the test bench roller 5 is driven to rotate. If both the test bench roller 5 and the tire 6 are driven to rotate, then longitudinal forces and moments, braking maneuvers and acceleration maneuvers can be simulated, or, if necessary, lateral forces can also be generated. For this purpose, the tire 6 and the test bench roller 5 can also rotate at different speeds.

[0027] In the test rig arrangement 1, a test rig control unit 29 (Fig. 2) can be provided, which generates setpoints SW for the tire drive 22 and / or setpoints SR for the roller drive 8 and controls the tire drive 22 and / or the roller drive 8 accordingly. A specific test run is implemented using the test rig arrangement 1 via the setpoints SW and SR. During operation of the test rig arrangement 1, a temporal sequence of setpoints, generally in predefined control time steps, usually in the millisecond or microsecond range, is generated, which is used to control the tire drive 22 and / or the roller drive 8. A specific test run is implemented using the test rig arrangement 1 via the setpoints SW and SR, specifically the temporal profile of at least one of these setpoints SW and SR. A setpoint SW or SR can be a target speed or a target torque of the tire 6 and / or the test rig roller 5, which is set by the tire drive 22 and / or the roller drive 8.The test bench control unit 29 is typically a microprocessor-based hardware, such as a microcontroller, a computer, etc., on which control software runs.

[0028] In the first position of the tire 6 in the housing, the tire axis of rotation 7 and the roller axis of rotation 9 are essentially parallel to each other. This first position corresponds to a straight-ahead position, in which the tire would be aligned without camber on a vehicle without steering input. In the straight-ahead position, the tire axis of rotation 7 and the roller axis of rotation 9, which are parallel to each other, define a vertical plane perpendicular to the tire contact patch 13.

[0029] In one possible embodiment of the test rig arrangement 1, a tire adjustment drive 26 (Fig. 2) is provided, which can be used to move the tire 6 into a different position in which the tire axis of rotation 7 and the roller axis of rotation 9 are not parallel. This would allow for the adjustment of a certain tire camber and / or the adjustment of a certain steering angle of the tire 6. It is also possible to adjust the contact force with which the tire 6 rests on the test rig roller 5 using the tire adjustment drive 26. Adjustment of lateral or longitudinal forces is also possible. The tire adjustment drive 26 is preferably arranged outside the enclosure 2 and projects into the enclosure 2 through a boundary wall of the enclosure 2.

[0030] In another variant, the tire 6 can also be arranged on a wheel suspension within the housing 2. In this case, the steering angle could also be adjusted by a tire actuator 26 acting on a track rod of the wheel suspension, which can also cause a change in the tire camber via the wheel suspension. In the case of a wheel suspension, a steering angle can also lead to a change in the tire camber.

[0031] Instead of adjusting the tire 6 in the housing 2, in one embodiment it is of course also possible to adjust the test stand roller 5 relative to the tire 6 by means of a roller actuator 27 (indicated by dashed lines in Fig. 2) in order to set a steering angle and / or a tire camber and / or a contact force and / or another force.

[0032] The tire actuator 26 and / or the roller actuator 27 can also be controlled by the test bench control unit 29 with corresponding setpoints S1, S2 to carry out a test run (as indicated in Fig. 2).

[0033] Thus, a test stand arrangement 1 with a steerable tire 6 and a fixed test stand roller 5, or a test stand arrangement 1 with a fixed tire 6 (non-steerable) and a steerable test stand roller 5, or a combination of both is possible. Essentially, in such a configuration, the tire rotation axis 7 and the roller rotation axis 9 in the test stand arrangement 1 can be adjusted relative to each other.

[0034] To adjust the steering angle, for example, the tire 6 is rotated about a vertical axis HA (Fig. 2) using the tire actuator 26 and / or the test stand roller 5 using the roller actuator 27. Similarly, a ground force in the direction of the vertical axis HA could be set or adjusted.

[0035] A steering angle or tire camber only results, of course, when a test run is carried out with the test stand setup 1. In a rest position of the test stand setup 1, in which no tire 6 is arranged in the housing 2, the tire rotation axis 7 (which is defined by the rotation axis of the tire holder) and the roller rotation axis 9 are preferably parallel to each other. In the rest position, for example, a tire 6 is mounted in or removed from the housing 2.

[0036] In the case of a tire actuator 26 or a roller actuator, these can also be controlled by the test bench control unit with corresponding setpoint values ​​during a test run. Likewise, it is possible to arrange more than one tire 6 in the housing 2 and simultaneously roll it on the test bench roller 5 during a test run with the test bench arrangement 1.

[0037] During a test run with the test rig 1, the tire 6 rolls on the test rig roller 5 at its contact patch 13. The contact patch 13 is dependent on the relative position of the tire's axis of rotation 7 and the roller's axis of rotation 9. This rolling motion allows tire abrasion to be generated during testing, simulating the wear that occurs during normal use of a tire 6 in road traffic. The objective of the test rig 1 according to the invention is to generate tire abrasion as realistically as possible and to capture the generated tire abrasion with minimal losses and other interference in order to evaluate it. "Realistic" in this context means that the tire abrasion corresponds as closely as possible to the tire abrasion that would occur when the tire is used on a vehicle and the vehicle is driven along a roadway in normal traffic.When a test run is performed with test bench setup 1, a predetermined driving route is simulated. The driving route is replicated using the target values ​​specified by the test bench control unit. During a test run with test bench setup 1, the position of the tire rotation axis 7 relative to the roller rotation axis 9 can also be changed, allowing adjustment of both steering angle and tire camber. Similarly, a simulated vehicle speed can be changed during a test run by adjusting the tire rotation speed and / or the roller rotation speed.

[0038] The test rig 1 can also be used to detect brake dust. For this purpose, the tire 6, together with a brake (not shown), such as a floating caliper brake or drum brake, could be arranged in the housing 2. During a test run with the test rig 1, the tire can be braked via the brake, thus generating brake dust. The brake dust can then be removed from the housing 2 together with tire dust.

[0039] In another possible embodiment, the brake for tire 6 is arranged outside the enclosure 2. This allows tire 6 to be actively braked during a test run with the test rig 1. The resulting brake abrasion is generated outside the enclosure 2 and therefore does not mix with tire abrasion generated inside the enclosure 2. This can enable a more accurate assessment of the tire abrasion. An air supply duct 11 for supplying fresh air to the interior of the enclosure 3 and an exhaust air duct 12 for removing exhaust air from the interior of the enclosure 3 are arranged on the enclosure 2. The air supply duct 11 and the exhaust air duct 12 open into the interior of the enclosure 3 at respective outlet areas 11a and 12a, respectively. During a test run with the test rig 1, fresh air is supplied with a supply air volume flow rate V. zu supplied and exhaust air with an exhaust air volume flow V abdischarged. The supply air volume flow V zu and the exhaust air volume flow V ab They can be the same or different. For this purpose, at least in the supply air duct 11 or exhaust air duct 12, a blower 23, 24 (Fig. 2), preferably one blower in each, is provided to generate the airflow.

[0040] By supplying fresh air into the interior of the enclosure 3 and simultaneously extracting exhaust air from the interior of the enclosure 3, an airflow L (indicated by an arrow in Figs. 1 and 2) is created in the interior of the enclosure 3 of the enclosure 2, flowing from the outlet 11a of the supply air duct 11 to the outlet 12a of the exhaust air duct 12. This airflow L carries abrasion particles within the enclosure 2 and removes them from the enclosure 2. By controlling the supply air volume flow V zu and / or the exhaust air volume flow V abThis airflow L can be controlled during a test run using the test rig setup 1 so that as many abrasion particles as possible are carried away by the airflow L. The flow velocity of this airflow L should not be too low to prevent heavier abrasion particles from being carried along and settling in the enclosure 2 due to gravity and depositing on the floor. However, the flow velocity of the airflow L should also not be too high to avoid particle loss due to impaction. Impaction refers to the effect that abrasion particles cannot follow the airflow L and / or changes in its direction, but instead, due to their inertia and any centrifugal forces acting upon them, move in the direction of their motion, for example, circumferentially or tangentially around the tire 6.The airflow L can be appropriately determined for each application, for example by means of appropriate tests.

[0041] The supply air to the enclosure 2 can also be conditioned, which may include filtration, temperature control, pressure regulation, humidity control, etc. In particular, the supply air is particle-free, meaning that it contains no or only a negligible number of particles within a specified particle size range relevant for measurement. During a test run with the test rig 1, the exhaust air duct is connected to at least one abrasion measuring device 20. The abrasion measuring device 20 receives at least one measuring volume flow rate V. m , which is at least a partial volume flow of the exhaust air volume flow V ab is. For this purpose, the measuring volume flow rate V can be used. mbranching off from the exhaust air line 12, whereby it may be advantageous for the abrasion measurement if the branching is isokinetic, i.e., such that the flow velocity of the measuring volume flow V m essentially the same as the exhaust air volume flow V ab corresponds.

[0042] In principle, several measuring volume flows V can also be taken from the exhaust air duct 12. m The exhaust air can be diverted and fed to different abrasion measuring devices 20 to measure, for example, different properties of the abrasion, such as abrasion size distribution, abrasion mass, abrasion particle count, etc. Such measuring devices are well known. Frequently used measuring devices are a condensation particle counter or a diffusion charge sensor, which are well known. In addition, further measuring devices can be provided that measure not the abrasion, but other parameters of the exhaust air flow.

[0043] It is also known to determine the exhaust air volume flow V ab or the measuring volume flow rate V m The solution is to be diluted in a dilution unit in a predetermined ratio before being used with an abrasion measuring device 20, in order to reduce the abrasion particle concentration for measurement. The dilution is carried out, for example, with particle-free air. Particle-free means that no or only a negligible number of particles are present within a predetermined particle size range that is relevant for the measurement.

[0044] According to the invention, the supply air duct 11 has a longitudinal axis L at its entry into the interior space 3 of the enclosure 2. zu and an air supply duct cross-section A zu (normal to the longitudinal axis L) zu The supply air duct cross-section A zu The supply air duct 11 has a constant supply air duct cross-section A before the housing 2. zu , at least over a certain length of the supply air duct 11.

[0045] The longitudinal axis L zu The air supply duct cross-section is located below a plane E that runs through the tire rotation axis 7 and is parallel to a tangent T through the highest point O of the part of the test stand roller 5 projecting into the interior of the enclosure 5 (Fig. 3). Advantageously, the air supply duct cross-section is located entirely below plane E, as for example in the embodiment shown in Fig. 3. The imaginary extension of the air supply duct cross-section A present at the opening into the interior of the enclosure 3 zu in the direction of the longitudinal axis L zuThe air supply line 11 into the enclosure interior 3 (shown with a dashed line in Fig. 3 and Fig. 4) preferably runs completely below the plane E in the enclosure interior 3, which runs through the tire rotation axis 7 and is parallel to a tangent T through the highest point O of the part of the test stand roller 5 projecting into the enclosure interior 3 (Fig. 3).

[0046] For the sake of simplicity, the present disclosure refers in this context to a highest point O, which is shown in the sectional views according to Figures 2 and 3. However, it is immediately obvious to a person skilled in the art that the test stand roller 5 is essentially a cylinder and therefore the highest point O in a top view of the test stand roller 5 is represented as a straight line running along the roller's axis of rotation 9 in Figure 4.

[0047] The highest point O is the point on the test stand roller 5 that projects furthest into the interior of the enclosure 3. This is not a fixed point O on the test stand roller 5, but rather, in the case of rotation of the test stand roller 5 during a test run with the test stand arrangement according to the invention, that part of the test stand roller 5 which projects furthest into the enclosure 3 at the respective time during the rotation of the test stand roller 5.

[0048] These measures ensure that the intake air in the enclosure 2 is supplied in an area that, when extrapolated to the wheel arch of a vehicle, is located near the road surface. A flow also forms between the underbody of a real vehicle and the road surface, which is now replicated by the enclosure. This supply within the enclosure thus creates realistic flow conditions, enabling realistic test runs with the test rig setup 1.

[0049] The imagined extension of the supply air duct cross-section A zu into the interior of the enclosure 3 in the direction of the longitudinal axis L zu The supply air duct 11 preferably also includes the highest point O (as in Fig. 3). In other words, the imaginary extension of the supply air duct cross-section A surrounds zu in the direction of the longitudinal axis L zuThe air supply line 11 into the interior of the housing 2 preferably also extends to the highest point O. This ensures that the part of the test stand roller 5 on which the tire 6 rests during a test run (which corresponds to the road surface of a real vehicle) is also supplied with air. This creates even more realistic flow conditions, closely resembling those in a vehicle's wheel well. The imaginary extension of the air supply line cross-section A zu in the direction of the longitudinal axis L zuIn a further embodiment of the invention (as in Fig. 3), the air supply line 11 into the interior of the housing 3 includes at least part 13a of the tire contact surface 13 that forms during a test run with the test stand arrangement 1, in which the tread 6a of the tire 6 comes into contact with the test stand roller 5 when the tire 6 rolls on the roller tread 5a of the test stand roller 5, viewed in the direction of rotation of the tire 6. In other words, the imaginary extension of the air supply line cross-section A surrounds zu at junction in the direction of the longitudinal axis L zu the supply air line 11 into the enclosure interior 3 at least the part 13a of the tire contact surface 13 that forms during a test run with the test stand arrangement 1, in which the tread surface 6a of the tire 6 comes into contact with the test stand roller 5 when the tire 6 rolls on the roller tread surface 5a of the test stand roller 5 seen in the direction of rotation of the tire 6.

[0050] The imagined extension of the supply air duct cross-section A zu in the direction of the longitudinal axis L zu In a further embodiment of the invention, the air supply line 11 into the housing interior 2 also includes a portion of the roller tread 5a, which, when the tire 6 rolls on the roller tread 5a of the test stand roller 5 in the direction of rotation of the test stand roller 5, lies in front of the portion 13a of the tire contact surface 13, which, when the tire 6 rolls on the roller tread 5a of the test stand roller 5 in the direction of rotation of the tire 6, comes into contact with the test stand roller 5. In other words, the imaginary extension of the air supply line cross-section A surrounds zu in the direction of the longitudinal axis L zuthe supply air line 11 into the housing interior 2 preferably also a part of the roller running surface 5a, which, when the tire 6 rolls on the roller running surface 5a of the test stand roller in the direction of rotation of the test stand roller 5, lies in front of the part 13a of the tire contact surface 13, which, when the tire 6 rolls on the roller running surface 5a of the test stand roller 5 seen in the direction of rotation of the tire 6, comes into contact with the test stand roller 5.

[0051] By supplying air to the test stand roller 5, any abrasion particles adhering to the roller running surface 5a of the test stand roller 5 can be loosened and carried away from the housing 2 by the airflow L. This improves the measurement of the abrasion particles because less particle loss occurs.

[0052] Preferably, the supply air, fed into the enclosure via the supply air duct 11, is directed towards the tire contact patch 13 that forms during a test run with the test rig arrangement 1. Essentially, it is not necessary for the entire tire contact patch 13 to be exposed to the supply air, but at least the portion 13a of the tire contact patch 13 in which the tread 6a of the tire 6 comes into contact with the test rig roller 5 when the tire 6 rolls on the test rig roller 5 in the direction of rotation of the tire 6. This is shown schematically in a side view in Fig. 3 and in a top view in Fig. 4, where the supplied supply air in the enclosure 2 is represented by the airflow L.

[0053] Figure 3 shows in particular that the supply air supplied via the supply air duct 11 is preferably supplied to the tire contact patch 13, which forms during a test run with the test stand arrangement 1, at least across the tire contact patch width B as seen in the direction of the tire rotation axis 7. Figure 3 also shows that the exhaust air duct 12 discharges the exhaust air from the housing 2, in the direction of the tire rotation axis 7, over a width that is at least as wide as the tire contact patch width B of the tire contact patch 13, which forms during a test run with the test stand arrangement 1.

[0054] A roller gap 4a forms between the test stand roller 5 and the roller recess 4 of the housing 2. This roller gap 4a prevents direct contact between the test stand roller 5 and the housing 2. The imaginary extension of the supply air duct cross-section A zuin the direction of the longitudinal axis L zu The air supply line 11 into the housing interior 2 preferably also includes the portion of the roller gap 4a which, when the tire 6 rolls on the roller tread 5a of the test stand roller 5 in the direction of rotation of the test stand roller 5, lies in front of the portion 13a of the tire contact surface 13 which, when the tire 6 rolls on the roller tread 5a of the test stand roller 5 in the direction of rotation of the tire 6, comes into contact with the test stand roller 5. In this way, the airflow L can create a kind of air curtain in the area of ​​the roller gap 4a, which can suppress or at least reduce the penetration of foreign particles through the roller gap 4a into the housing interior. At the same time, this can retain abrasion particles in the housing interior 3. This reduces the potential for foreign particles to distort the measurement of abrasion particles.

[0055] An air curtain in the area of ​​the roller gap 4a can also be generated by a nozzle arrangement 28 (indicated by dashed lines in Fig. 3) which directs purge air S at least partially onto the test rig roller 5, specifically onto the roller running surface 5a, in the area of ​​the roller gap 4a. The purge air S thus has a flow component that is directed radially towards the test rig roller 5. The nozzle arrangement 28 can be designed such that purge air S is directed onto the test rig roller 5 in the area of ​​the entire roller gap 4a. The purge air S forms a purge air curtain in the area of ​​the roller gap 4a, which can suppress or at least reduce the ingress of foreign particles through the roller gap 4a into the interior of the enclosure.

[0056] Such a purge air curtain with purge air can be provided on the side of the inlet 11a of the supply air duct 11 (as shown in Fig. 3). This primarily serves to prevent ambient air from entering the enclosure interior 3, which could introduce foreign particles into the enclosure interior. Additionally or alternatively, such a purge air curtain with purge air can also be provided on the side of the outlet 12a of the exhaust air duct 12 (not shown in Fig. 3). This primarily serves to prevent abrasion particles from leaving the enclosure interior, which leads to particle loss and a distortion of the abrasion particle measurement. Because at least part of the purge air S is directed towards the test rig roller 5, the purge air S also dislodges abrasion particles adhering to the roller running surface 5a. This improves the measurement of the abrasion particles because less particle loss occurs.

[0057] The nozzle arrangement includes at least one air nozzle, and usually an arrangement of several air nozzles. The air nozzles can also be positioned at different locations to create a curtain of purge air at different points.

[0058] The purge air S is preferably conditioned, in particular particle-free. Thus, the purge air S contains no or only a negligible number of particles within a specified particle size range relevant for the measurement. The purge air S and the supply air can also originate from the same source and therefore be identical.

[0059] In this context, it is also advantageous to generate a curtain of purge air across the entire roller gap 4a, which would largely suppress or at least reduce the ingress of foreign particles into the housing interior via the roller gap 4a. This would further reduce any potential distortion of the measurement of abrasion particles by foreign particles. Such a purge air curtain can be achieved by arranging a nozzle assembly 28 directed towards the roller gap 4a, through which purge air S is supplied.

[0060] The housing 2 can also be funnel-shaped at the outlet 11a of the supply air duct 11, as shown in Fig. 1 and Fig. 2. This funnel-shaped expansion is considered part of the housing. The supply air duct cross-section A zuThe air duct 11, at its junction with the housing 2, is thus located at the point where the supply air duct 11 transitions into this funnel-shaped expansion (as indicated in Fig. 2). The airflow supplied via the supply air duct will not spread uniformly across the funnel within the expansion, but will instead flow predominantly in the direction of the longitudinal axis L. zu continue flowing through the supply air duct 11.

[0061] Likewise, to reduce potential abrasion particle losses, it is advantageous if the housing 2 is also funnel-shaped at the outlet 12a of the exhaust duct 12. The housing 2 thus tapers funnel-shaped towards the exhaust duct 12. The supply air duct 11 and the exhaust duct 12 can have any cross-section. A circular, oval, or polygonal cross-section is advantageous.

[0062] In a preferred embodiment, the air supply line 11, and preferably also the exhaust air line 12, are arranged between the tire rotation axis 7 and the roller recess 4, preferably closer to the roller recess 4. This allows for the simulation of a ground-level airflow onto the tire contact patch 13 of the tire 6, as would occur in a vehicle wheel well. This enables more realistic test runs with the test bench setup because the conditions in a vehicle wheel well are better replicated. The exhaust air line can be arranged in the same way.

[0063] 12 be arranged, but opposite the tire rotation axis 7 of the air supply line 11.

[0064] It is further advantageous if the supply air duct 11 is deflected from a substantially radial orientation towards the test stand roller 5 (for example, normal to the test stand floor 10) to a more tangential orientation towards the test stand roller 5 before entering the interior of the enclosure, as shown in Fig. 2. The deflection is, for example, 45° to 90°. Such a deflection directs the airflow L exiting the supply air duct 11 more towards the roller running surface 5a of the test stand roller 5. This also allows for a closer airflow to the tire contact patch.

[0065] 13. This could also be achieved by a flow guide plate in the supply air duct 11 before it enters the interior of the enclosure 3. The flow guide plate would be arranged so that the airflow L exiting the supply air duct 11 is directed more towards the roller running surface 5a of the test stand roller 5.

[0066] It has proven advantageous if the planned bends in the exhaust duct 12 are designed with sufficiently large radii of curvature to prevent impact in the exhaust duct 12. Radii of curvature of at least twice the diameter of the exhaust duct 12 should be aimed for. The number of bends in the exhaust duct 12 should be reduced as much as possible. Similarly, with regard to the extraction of abrasion particles, it is advantageous if a calming section is provided before and after the abrasion particle extraction point (branch of the measuring line 25) in the exhaust duct 12 to achieve the most uniform flow profile possible. The calming section before the abrasion particle extraction point should correspond to at least five times the diameter of the exhaust duct 12, and the section after the abrasion particle extraction point to at least twice the diameter of the exhaust duct 12.To reduce or suppress the ingress of foreign particles from outside the enclosure 2 into the interior of the enclosure 3, the supply air volume flow V could be adjusted. zu and the exhaust air volume flow V ab an overpressure inside the enclosure

[0067] 3 will be generated.

[0068] To reduce the ingress of foreign particles into the interior of the enclosure 3, an advantageous embodiment provides that the test rig roller 5 on the test rig assembly 1 is also enclosed by a roller enclosure 30, as indicated by the dashed lines in Fig. 2. The roller enclosure 30 adjoins the enclosure 2, or rather, these are separated from each other only by the lower boundary wall (test rig floor 10). The roller enclosure 30 has the particular effect of preventing foreign particles from entering the area of ​​the enclosure 2 containing the abrasion particles. Such foreign particles can distort the abrasion measurement. The roller gap 4a at the roller recess allows for this.

[0069] 4 Between the rotating test stand roller 5 and the housing 2, foreign particles can enter the housing 2, which can be avoided, or at least suppressed, by the roller housing 30.

[0070] As already mentioned, the enclosure comprises two boundary walls. In the embodiment shown in Figures 1 and 2, the enclosure 2 comprises two side walls 15 and 16, a front wall 17 (omitted in Figure 1 to show the interior of the enclosure 2), a rear wall 18, and an upper boundary wall 19. The enclosure 2 can also include a lower boundary wall 14, in which the roller recess 4 is formed. The lower boundary wall 14 is arranged opposite the upper boundary wall 19 with respect to the tire rotation axis 7. However, the roller recess 4 can also be formed in the test stand floor 10, in which case the lower boundary wall 14 can be omitted, or the test stand floor 10 can form the lower boundary wall 14 in this area.

[0071] In an advantageous embodiment according to Fig. 1, the two side walls 15, 16 are essentially parallel to each other and parallel to the tire rotation axis 7 in the straight-ahead position of the tire 6 (without steering angle and without tire camber), and the front wall 17 and rear wall 18 are aligned perpendicular to the tire rotation axis 7 in the straight-ahead position of the tire 6. The side walls 15, 16 are arranged opposite each other with respect to the tire rotation axis 7. In this embodiment, the front wall 17 and the rear wall 18 are aligned perpendicular to the tire rotation axis 7 in the straight-ahead position of the tire 6. The side walls 15, 16 transition into the front wall 17 and the rear wall 18 to form the housing interior 3. These walls can, in principle, be designed in any desired shape, orientation, geometry, etc.The supply line 11 and the exhaust line 12 preferably open into the housing in the area of ​​the side walls 15, 16, with one of these lines opening into each of these walls. The supply line 11 and the exhaust line 12 are therefore arranged opposite each other with respect to the tire rotation axis 7. In a preferred embodiment of the housing 2, the outlet areas 11a, 12a of the supply line 11 and exhaust line 12 are aligned with each other.

[0072] The front wall 17, or any other of the boundary walls of the enclosure 2, can also be removable from the enclosure 2 in order to make the interior of the enclosure 3 accessible from the outside, for example to be able to place a tire 6 in the enclosure 2.

[0073] The upper boundary wall 19 is arranged on the housing 2 opposite the roller recess 4 and is at least partially arcuate. Preferably, the upper boundary wall 19 is entirely arcuate. The arcuate upper boundary wall 19 is convexly curved outwards with respect to the interior of the housing 3. The arcuate, outwardly curved section of the upper boundary wall lies in a cross-sectional plane that is perpendicular to the roller axis of rotation 9. In the straight position of the tire 6, the cross-sectional plane is also perpendicular to the tire axis of rotation 7. In the illustration of Fig. 2, this cross-sectional plane is the drawing sheet surface.

[0074] The arc-shaped upper boundary wall 19 transitions into the side walls 15 and 16. The transition from the arc-shaped upper boundary wall 19 to the first side wall 15 and the second side wall 16 is located closer to the tire contact patch 13 than a vertex of the arc-shaped upper boundary wall 19. Preferably, the transitions to the first side wall 15 and the second side wall 16 are arranged at the same distance from the tire contact patch 13.

[0075] In the test rig arrangement 1, the tire 6 to be tested is positioned between the upper boundary wall 19 and the test rig roller 5, which projects into the housing 2 through the roller recess 4. As already described, the tire 6 rests on the test rig roller 5 at its contact surface 13. A gap is provided between the tire 6 and the housing 2, in particular between the tire 6 and the arcuate section of the upper boundary wall 19 and the side walls 15, 16, so that the tire 6 does not touch the housing 2. This is also illustrated in Fig. 2. Thus, a tire chamber for receiving the tire 6 is formed in the housing 2 between the upper boundary wall 19 and the roller recess 4, with the tire chamber being part of the interior of the housing 3.

[0076] Fig. 2 also shows a supply air blower 23 in the supply air duct 11 and an exhaust air blower 24 in the exhaust air duct 12. Fig. 2 also shows a measuring line 25 branching off from the exhaust air duct 12, which is connected to the abrasion measuring device 20.

[0077] The arched, outwardly curved upper boundary wall 19 of the enclosure 2 replicates a vehicle wheel arch. The space available in a vehicle wheel arch is very limited and is only as large as necessary to accommodate, in particular, a tire, possibly with its suspension. These confined spaces within a wheel arch influence the airflow, especially the airflow around the tire, and the cooling of the tire by this airflow. This, in turn, affects tire wear. This also applies essentially to a brake system, which is likewise located within the wheel arch of a vehicle. By replicating the wheel arch with the enclosure 2, more realistic tests of tire and / or brake wear can be performed with the test rig 1, because the airflow conditions within the enclosure 2 approximate those in a real wheel arch.

[0078] The arc-shaped, outwardly curved upper boundary wall 19 has the further advantage that no flow dead zones or turbulence form in the upper area of ​​the enclosure 2 where tire abrasion accumulates but is not carried away from the enclosure 2 by the airflow. This would negatively affect the detection of tire abrasion because not all of the tire abrasion would be carried away via the discharge line 12 and supplied for measurement. In particular, the arc-shaped, outwardly curved upper boundary wall 19 reduces the volume of the enclosure 2. This allows a sufficient velocity field to be generated within the enclosure 2 to reliably carry away the abrasion. Zones with zero flow velocity can thus be avoided within the enclosure 2.

[0079] The arc-shaped form of the upper boundary wall 19 of the enclosure 2 can of course only be approximated, for example by a polygonal design.

[0080] The arched, outwardly curved upper boundary wall 19 ensures that the tire 6 under test is subjected to a realistic airflow pattern (similar to the conditions in a vehicle wheel well) within the housing 2. This guides the abrasion particles (from the tire and / or brake) generated during the tire 6 test within the housing 2 in a manner consistent with real-world conditions. This contributes to an improved measurement of a property of the abrasion particles.

Claims

Patent claims 1. Test rig arrangement, in particular for determining tire and / or brake wear, wherein the test rig arrangement (1) has at least one enclosure (2) defining an interior space (3), wherein an air supply line (11) for supplying air into the interior space (3) and an exhaust air line (12) for removing exhaust air from the interior space (3) are arranged on the enclosure (2), wherein the exhaust air line (12) is connected or connectable to at least one wear measuring device (20), and wherein at least one test rig roller (5) rotatably mounted about a roller pivot axis (9) is provided in the test rig arrangement (1), which projects at least partially into the interior space (3) through a roller recess (4) of the enclosure (2),and when performing a test run with the test stand arrangement (1) in the interior of the enclosure (3) at least one tire (6) to be tested can be rotatably arranged about a tire rotation axis (7) and the tire (6) to be tested rolls with a tire tread (6a) on a roller tread (5a) of the at least one test stand roller (5) and the tire tread (6a) contacts the test stand roller (5) at a tire contact surface (13), characterized in that the supply air line (11) has a longitudinal axis (L, zu ) has and that the longitudinal axis (L zu ) is located below a plane (E) which passes through the tire rotation axis (7) and is parallel to a tangent (T) through the highest point (O) of the part of the test stand roller (5) projecting into the enclosure interior (3).

2. Test bench arrangement according to claim 1, characterized in that the supply air duct (11) has a supply air duct cross-section (A) zu ) enters the interior of the enclosure (3) and the supply air duct cross-section (A zu ) is located completely below level (E).

3. Test rig arrangement according to claim 1, characterized in that the supply air duct (11) has a supply air duct cross-section (A) at the point where it enters the interior of the enclosure (3). zu ) has and an imaginary extension of this supply air duct cross-section (A zu ) in the direction of the longitudinal axis (L zu ) the supply air duct (11) into the enclosure interior (3) runs completely below level (E) in the enclosure interior (3).

4. Test rig arrangement according to one of claims 1 to 3, characterized in that the supply air duct (11) has a supply air duct cross-section (A) at the point where it enters the interior of the enclosure (3). zu) has and an imaginary extension of this supply air duct cross-section (A zu ) in the direction of the longitudinal axis (L zu ) the supply air duct (11) into the enclosure interior (3) includes the highest point (O) of the test stand roller (5).

5. Test bench arrangement according to claim 3 or 4, characterized in that the imaginary extension of the supply air duct cross-section (A) zu ) into the interior of the enclosure (3) includes the part of the tire contact area (13) that forms during a test run with the test stand arrangement (1), with which the tire running surface (6a) comes into contact with the test stand roller (5) when the tire (6) rolls on the roller running surface (5a) of the test stand roller (5).

6. Test rig arrangement according to one of claims 3 to 5, characterized in that the imaginary extension of the supply air duct cross-section (A) zu) into the interior of the housing (3) includes a part of the roller tread (5a) which, when the tire (6a) rolls on the roller tread (5a) of the test stand roller (5) in the direction of rotation of the test stand roller (5) lies in front of the part of the tire contact surface (13).

7. Test stand arrangement according to one of claims 1 to 6, characterized in that the supply air supplied via the supply air line (11) into the housing (2) is directed towards the tire contact surface (13) that forms when a test run is carried out with the test stand arrangement (1).

8. Test rig arrangement according to one of claims 1 to 7, characterized in that the imaginary extension of the supply air duct cross-section (A zu ) in the direction of the longitudinal axis (L zu) the air supply line (11) into the housing interior (3) includes a part of a roller gap (4a) between the roller recess (4) and the roller running surface (5a), which, when the tire (6) rolls on the roller running surface (5a) of the test stand roller (5) in the direction of rotation of the test stand roller (5) lies in front of the tire contact surface (13).

9. Test stand arrangement according to one of claims 1 to 8, characterized in that a nozzle arrangement (28) is provided on the test stand arrangement (1) which is configured to direct rinsing air (S) onto the test stand roller (5) in the area of ​​a roller gap (4a) between the roller recess (4) and the roller running surface (5a) to form a rinsing air curtain.

10. Test stand arrangement according to one of claims 1 to 9, characterized in that the supply air line (11) supplies the supply air into the enclosure (2) over a width that is at least as wide as a tire contact area width (B) in the direction of the tire rotation axis (7) of the tire contact area (13) that forms when a test run is carried out with the test stand arrangement (1).

11. Test rig arrangement according to one of claims 1 to 10, characterized in that the exhaust air duct (12) discharges the exhaust air from the enclosure (2) over a width that is at least as wide as a tire contact patch width (B) in the direction of the tire rotation axis (7) which changes during a test run with the test stand arrangement (1) forming tire contact patch (13).

12. Test stand arrangement according to one of claims 1 to 11, characterized in that the supply air line (11) and the exhaust air line (12) are arranged opposite each other on the housing (2) with respect to the tire rotation axis (7).

13. Test rig arrangement according to one of claims 1 to 12, characterized in that the enclosure (2) widens in a funnel shape after the inlet of the supply air line (11) into the enclosure (2) and / or the enclosure (2) narrows in a funnel shape towards the exhaust air line (12).

14. Test rig arrangement according to one of claims 1 to 13, characterized in that the enclosure (2) comprises two side walls (15, 16) which are arranged opposite each other with respect to the tire rotation axis (7) and the inlet (11a) of the supply air line (11) into the enclosure (2) is provided on one of the two side walls (15, 16) and the outlet (12a) of the exhaust air line (12) from the enclosure (2) is provided on the other of the two side walls (15, 16).

15. Test rig arrangement according to one of claims 1 to 14, characterized in that a supply air blower (23) is provided in the supply air duct (11) which supplies the supply air to the enclosure (2) when a test run is carried out with the test rig arrangement (1) and / or an exhaust air blower (24) is provided in the exhaust air duct (12) which removes the exhaust air from the enclosure (2) when a test run is carried out with the test rig arrangement (1).

16. Test rig arrangement according to one of claims 1 to 15, characterized in that a supply air blower (23) is provided in the supply air duct (11), which supplies the supply air to the enclosure (2) when a test run is carried out with the test rig arrangement (1), and that the supply air blower (23) supplies the supply air relative to an ambient pressure of the enclosure. (2) conveys into the enclosure (2) under overpressure.

17. Test rig arrangement according to one of claims 1 to 15, characterized in that a supply air blower (23) is provided in the supply air duct (11), which supplies the supply air to the enclosure (2) during a test run with the test rig arrangement (1), and an exhaust air blower (24) is provided in the exhaust air duct (12), which discharges the exhaust air from the enclosure (2) during a test run with the test rig arrangement (1), and that a supply air volume flow {V} generated by the supply air blower (23) zu ) the supply air in the Essentially the same as an exhaust air volume flow V generated with the exhaust air blower (24). ab ) the exhaust air.

18. Test stand arrangement according to one of claims 1 to 17, characterized in that a roller housing (30) is provided which is connected to the housing (2) and the roller housing (30) surrounds the test stand roller (5) at least partially, preferably completely, except for the part projecting into the interior of the housing (3).

19. Test stand arrangement according to one of claims 1 to 18, characterized in that the roller axis of rotation (9) and the tire axis of rotation (7) are adjustable relative to each other.

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