Tire monitoring device, motor vehicle and method for monitoring the condition of a tire

Abstract

A tire monitoring device (12) for installation on a motor vehicle (10) and for monitoring the condition of a tire (13), wherein the tire monitoring device (12) comprises at least one sensor device (14) designed to detect at least one tire condition parameter (18) in a suitable installation position in which the sensor device (14) is located in a position (P0) spaced away from the tire (13), and an evaluation device (17) designed to check, depending on the detected tire condition parameter (18), according to at least one predetermined criterion, whether a defective condition (Z1, Z2, Z3, Z4) of the tire (13) exists, wherein the tire monitoring device (12) is designed to detect a tire condition parameter (18) that is different from the tread depth of the tire (13) than the tire condition parameter (18), characterized by the fact that the sensor device (14) is designed to detect a reflectance of different surface areas of the tire (13) as a tire condition parameter, wherein the evaluation device (17) is designed to - to check whether, during the rotation of the tire (13), there is a surface area in the circumferential direction (U) of the tire (13) whose reflectance value differs from that of another surface area by more than a predetermined value and / or whose reflectance value exceeds a predetermined limit value, and if this is the case, to detect a metallic foreign body on or in the tire (13); and / or - to detect contamination of the profile recesses by comparing a stored reference profile pattern with the recorded reflectance pattern; and / or - to determine, based on a stored reflectance reference value of the clean tire material of the tire (13), all areas of the tire (13) that are contaminated and / or contain foreign matter if, during the reflectance analysis, surface areas of the tire (13) are identified whose recorded reflectance values ​​differ from the reflectance reference value of the clean tire (13).

Description

[0001] The invention relates to a tire monitoring device for monitoring a condition of a tire, wherein the tire monitoring device has at least one sensor device which is designed to detect at least one tire condition parameter in a proper installation position in which the sensor device is located at a distance from the tire, and an evaluation device which is designed to check, depending on the detected tire condition parameter according to at least one predetermined criterion, whether a defective condition of the tire exists.

[0002] Tire pressure monitoring systems in production vehicles, for example, are known from the prior art. These can detect air pressure loss in tires and transmit a corresponding warning to the driver. Furthermore, DE 10 2006 055 059 A1 describes a device that can detect the tread depth of a tire, and a warning can be issued if excessive tread wear is detected. A laser scanner, for example, can be used to detect the tread depth.

[0003] Especially with commercial vehicles, good tire condition is a very important component for safe transport. For example, safety-relevant wear on the tires poses the risk of the tire bursting, which could seriously compromise safety. If a tire blowout occurs during transport with a heavy commercial vehicle, the consequences can be devastating. For example, it can lead to reduced driving stability or even uncontrollability of the commercial vehicle, tipping over, or overloading of the remaining tires due to a tire failure, as well as reduced braking performance, which can have drastic consequences, especially on routes with steep gradients. In addition, tire blowouts can also lead to fires, loss of cargo, and even environmental damage. Delays in delivery of the cargo to the recipient are also detrimental.In addition, the tire itself, which has been torn to pieces by the blowout, poses a significant hazard to surrounding and following traffic. Due to the sometimes very drastic consequences that a tire blowout can have, it is desirable to make tire monitoring as reliable as possible.

[0004] DE 10 2009 026 845 A1 describes a measuring device for determining tire parameters using a TOF sensor. Based on the time of flight or phase difference of the received light, a three-dimensional model of the detected illuminated tire surface can be created. Furthermore, not only can tread depth be determined, but also other tire parameters, such as the direction of rotation and / or the tire type, can be determined based on the three-dimensional model. Furthermore, it is possible to detect incorrect axle and track alignment.

[0005] WO 96 / 10727 A1 describes a tire scanner that can be used to determine, in particular, the tread depth of a tire, but also other tire parameters and defect states. For example, the presence of metal in or on the tire can be detected using induction technology to determine whether, for example, a nail is embedded in the tire. A laser or an ultrasonic sensor can also be used to measure the tread depth.

[0006] US 6,069,966 A and DE 10 2006 055 059 A1 each deal primarily with the laser-based detection and inspection of tire tread depth.

[0007] WO 2017 / 109688 A1 describes a method for checking tires for defects during production using a camera and a laser scanner, as well as a lighting system.

[0008] US 2002 / 0 189 336 A1 deals with the detection of defective tire conditions using radar and the evaluation of Doppler signals.

[0009] DE 196 25 763 A1 describes a device for testing the quality of tires by changing the field to which the tire is exposed, and DE 19 41 610 U describes a motor vehicle with twin tires, wherein a tire monitor with a button projects into the space between the tires, which is activated by touching the foreign body in the event of a foreign body in the space.

[0010] The object of the present invention is therefore to provide a tire monitoring device, a motor vehicle, and a method for monitoring a tire that enable the most comprehensive monitoring of a motor vehicle tire possible. This object is achieved by a tire monitoring device, a motor vehicle, and a method for monitoring a tire having the features according to the respective independent claims. Advantageous embodiments are the subject of the dependent patent claims, the description, and the figures.

[0011] A tire monitoring device according to the invention for monitoring the condition of a tire comprises at least one sensor device configured to detect at least one tire condition parameter in a proper installation position, in which the sensor device is located at a distance from the tire, and an evaluation device configured to check, depending on the detected tire condition parameter according to at least one predetermined criterion, whether the tire is in a defective condition. Furthermore, the tire monitoring device is configured to detect a tire condition parameter other than a tread depth of the tire as the tire condition parameter. Furthermore, the sensor device is configured to detect a reflectance of various surface areas of the tire as the tire condition parameter. The evaluation device is configured to - to check whether, in the circumferential direction of the tyre, during rotation of the tyre, there is a surface area whose reflectance value differs by more than a predetermined value from that of another surface area and / or whose reflectance value exceeds a predetermined limit, and, if this is the case, to detect a metallic foreign body on or in the tyre; and / or - to detect contamination of the profile recesses by comparing a stored reference profile pattern with the recorded reflectance pattern; and / or - to determine, on the basis of a stored reflectance reference value of the clean tire material of the tire, all areas of the tire that are contaminated and / or contain foreign bodies if the reflectance analysis detects surface areas of the tire whose recorded reflectance values ​​deviate from the reflectance reference value of the clean tire.

[0012] The invention is based on the realization that there are significantly more influencing factors than just the tread depth of a tire that can lead to a defective tire condition and resulting dangerous situations. Furthermore, there are defective tire conditions that not only pose an increased risk of a blowout, but also pose a high risk in other ways, particularly for other road users, and which cannot be determined by simply observing or recording the tread depth. Such defective conditions and influencing factors include, for example, tire damage, such as broken tread pieces, or foreign objects embedded in the tire, such as nails or screws.However, heavy tire contamination, as is often the case with agricultural vehicles, for example, can also pose significant risks. Firstly, due to the resulting reduced friction and secondly, because this contamination can also lead to contamination of the road surface, which poses a danger to following traffic. Stones trapped between the twin tires of a truck, for example, which can be thrown while driving, also pose an enormous safety risk for other road users. All of these other defective tire conditions can now be advantageously detected by examining tire condition parameters that go beyond the tread depth. This allows for significantly more comprehensive tire monitoring that goes beyond just considering the tread depth.

[0013] In principle, any sensor device can be used as the sensor device, such as a laser scanner, a radar sensor, a camera, an ultrasonic sensor, etc. However, the sensor device is preferably designed to detect a distance, in particular between the tire or a tire area currently located in the sensor device's field of view, and the sensor device. This can be achieved, for example, by a laser scanner, a stereo camera, other 3D cameras, such as a time-of-flight camera, radar sensors, or combinations of the aforementioned sensors. However, it is particularly advantageous if the sensor device is designed as a laser scanner. A laser scanner can advantageously detect numerous different defective states of a tire and also differentiate them from one another, so that no additional or further sensors are required for comprehensive tire monitoring.It is further advantageous if the laser scanner is designed to scan at least one area of ​​the tire surface arranged in the circumferential direction of the tire along several scan lines in the intended installation position. These scan lines can, for example, run at least substantially parallel to the wheel axis and capture the tire surface in the circumferential direction across the entire tire width. In principle, the provision of a single such scan line is sufficient, above all to capture the tire condition parameters described below and to be able to detect corresponding defective conditions from them. However, the provision of several such scan lines is advantageous because, especially when scanning along these scan lines is carried out sequentially in time, significantly more additional information can be provided, which makes the detection of defective conditions even more reliable and precise.

[0014] According to the invention, the sensor device is designed to detect a reflectance of various surface areas of the tire as a tire condition parameter, in particular during its rotation relative to the sensor device or its field of view. Furthermore, the evaluation device is designed, in particular, to determine at least one of the following defective tire conditions depending on the detected reflectance: the presence of a foreign body in the tire and / or in the tire tread and / or between two individual tires of a dual tire, and / or the presence of dirt within depressions in the tire tread and / or on the tire surface.

[0015] This is based on the realization that different materials have different reflective properties. This advantageously allows any type of foreign body or contamination on the tire to be detected. For example, if a tire is clean, i.e. it has no contamination or foreign bodies of any kind, the homogeneous tire material results in a consistent reflectance when viewing different surface areas of the tire in the circumferential direction. Such reflectance is expressed in particular in the intensity detected by the sensor device from the corresponding tire area. If the sensor device is a laser scanner, for example, the higher the reflectance in a certain area of ​​the tire, the more laser light that was irradiated and reflected in this area will be detected by the laser scanner's detection device.Different reflectances in different areas are expressed accordingly by different recorded intensity values ​​assigned to the respective areas. This also applies analogously to other sensor device designs, for example, as a radar sensor or a camera. If different reflectances are recorded in different areas of the tire, for example while the tire is rotating, it can be concluded that the tire has one of the defective conditions mentioned above. The evaluation device can therefore be designed to check whether areas of the tire surface in the circumferential direction of the tire have different reflectances during the tire's rotation. If so, the evaluation device determines a defective tire condition based on this criterion.

[0016] In addition, these defective conditions can also be differentiated by a more detailed analysis of the recorded reflectance in the different areas.

[0017] For example, metallic objects are characterized by particularly high reflectance. Metallic objects in the tire can thus advantageously be detected particularly well and reliably, for example by a laser scanner or radar sensor as the sensor device, since the difference in intensity to surrounding, non-metallic areas of the tire is particularly high. The evaluation device can therefore be designed to check whether, in the circumferential direction of the tire, there is an area during rotation of the tire whose reflectance value differs by more than a predetermined value from that of another tire area and / or whose reflectance value exceeds a predetermined limit. If this is the case, the evaluation device detects a metallic foreign body on or in the tire according to this criterion.If, for example, dirt such as earth, mud, sand and / or stones is found in the depressions of the tire tread, this results in a reflectance pattern from the contaminated depressions in the tread and the uncontaminated elevations of the tread. For this purpose, the tread pattern can also be saved as a reference. By comparing the reference tread pattern with the recorded reflectance pattern, the evaluation device can detect the contamination of the tread depressions. This can also be taken into account in an optional additional determination of the tread depth by only determining the tread depth or only determining it in those areas of the tire that have been classified as uncontaminated by the evaluation device. This can prevent a falsified result due to contamination when determining the tread depth.Alternatively or additionally, the reflectance value of the clean tire material can also be determined through calibration and stored. Based on such a reflectance reference of the clean tire material, the evaluation device can easily identify all areas of the tire that are contaminated and / or contain foreign bodies. This allows even large areas of contamination on the tire surface to be detected, for example, if the reflectance analysis detects large areas whose reflectance values ​​differ from those of the clean tire. Local reflectance deviations in predetermined small areas can also indicate the presence of foreign bodies in the tire, such as stones that may be trapped in depressions in the tire tread, or larger foreign bodies, such as stones between twin tires.This allows numerous specific defective conditions of the tire to be detected by observing the reflectance and, in addition, to be advantageously differentiated, for example according to the criteria described above.

[0018] Depending on a detected defective tire condition, a warning signal or a notification can be issued to the driver. Such a notification can then advantageously not only indicate that the tire is in a defective condition, but also contain information about which of the several different possible defective conditions the detected defective condition has been classified as. It is also possible to automatically initiate safety measures depending on a detected defective condition. For example, if tire contamination is detected, a cleaning device can be activated. Such a cleaning device can, for example, use high-pressure spray water or high-pressure air to clean the tire tread accordingly, particularly while the vehicle is moving or stationary.

[0019] However, not only reflectance represents a particularly advantageous tire condition parameter, but other tire condition parameters can also be used to detect further defective conditions or to detect the defective conditions already mentioned, as will be described in more detail below.

[0020] According to a further advantageous embodiment of the invention, the sensor device is designed to continuously record a distance profile of the distance between the sensor device and at least one region of the surface of the tire in the tire circumferential direction as the at least one tire condition parameter when the tire rotates relative to the sensor device. By analyzing this distance profile, defective conditions of a tire can also be detected. For example, it is particularly advantageous if the evaluation device is designed to check, based on the distance profile, whether the tire has a deformation in the tire circumferential direction, in particular whether the tire shape deviates from a circular shape by more than a predetermined amount in the circumferential direction. For example, it can be determined from the said distance profile whether, for example, the average distance of the profile, ieThe tire surface, viewed from the sensor device in the circumferential direction, fluctuates periodically with the tire's rotation time. If this occurs, tire imbalance or deformation can be detected. Such deformation, for example, allows conclusions to be drawn about insufficient tire pressure. Furthermore, one-sided damage or wear on the tire can also be detected.

[0021] In a further advantageous embodiment of the invention, the evaluation device is designed to compare the distance profile with a reference profile and, depending on the result of the comparison, to determine at least one of the following defective tire conditions: local damage to the tire and / or the presence of a foreign body in the tire and / or in depressions in the tire tread and / or between two individual tires of a twin tire, and / or the presence of dirt within depressions in the tire tread and / or on the tire surface. Thus, some of the defective tire conditions already mentioned above, such as the presence of foreign bodies in the tire, the presence of contamination, and the like, can be detected based on the observation of the distance profile and the comparison of this distance profile with a reference.In particular, this measure can also be carried out in addition to the reflectance measurement described above, which makes the detection of such defective conditions even more reliable and safer.

[0022] In other words, the tire tread can be measured in the circumferential direction of the tire while the tire rotates relative to the sensor device. The periodic pattern of the tire tread can then be continuously observed while driving around the circumference of the tire. By comparing the tread pattern observed in the past with the currently measured tread, i.e. based on deviations between the currently measured distance profile and the reference, numerous defective tire conditions can be detected, such as worn-in screws, other foreign objects on or between the tire, etc. A particularly advantageous feature is that this also allows damage to the tire, such as broken-off tread pieces, cuts, cracks, etc. to be detected.

[0023] In a further advantageous embodiment of the invention, the tire monitoring device is further configured to determine a tire's rotational speed. In other words, the tire monitoring device according to the invention and its configurations can not only be advantageously used for tire monitoring per se, but also provide particularly advantageous additional benefits, since the variables required for determining a tire's rotational speed can also be easily detected by the sensor device or are partially detected anyway. For example, the analysis of the detected distance profile in the tire's circumferential direction can be used to determine the rotational speed.For example, correlation analysis can be used to determine when a specific area of ​​a tire repeatedly passes through the sensor device's field of view, as even apparently uniform profiles always exhibit irregularities that can be used to detect when a complete wheel rotation has occurred. If the sensor device is designed as a laser scanner as described above, for example, the tire curvature and, from this, the tire diameter and the distance traveled per tire rotation, as well as the time required for this, can be determined based on several spatially offset scan lines. Determining the rotational speed is particularly advantageous for trucks, as these typically do not have wheel tick sensors. Therefore, detailed information about the wheel movement or vehicle movement, such as path speed and curve radius, is not known.However, modern driver assistance systems, maneuvering functions, and automated driving require very precise odometry data. The method presented here can advantageously provide this additional information and is therefore a very valuable source of information.

[0024] Furthermore, the invention also relates to a motor vehicle with a tire monitoring device according to the invention or one of its design variants.

[0025] It is further advantageous if the sensor device for monitoring the condition of a tire of the motor vehicle is arranged in a position spaced from the tire, which is located in front of the tire when the motor vehicle is traveling forward in the direction of travel. The sensor device can be attached to the vehicle frame in the direction of travel. This has the advantage that dirt and spray thrown off the tire only hit the measuring device to a small extent when traveling forward. In a particularly advantageous embodiment of the invention, the sensor system is mounted towards the front of the vehicle with respect to the tire. The motor vehicle can have a corresponding sensor device for each tire and optionally also a respective evaluation device or a common evaluation device for several sensor devices.

[0026] Furthermore, the invention also relates to a method for monitoring the condition of a tire, wherein at least one tire condition parameter is detected by means of a sensor device spaced from the tire, and depending on the detected tire condition parameter, it is checked according to at least one predetermined criterion whether a defective condition of the tire exists. In this case, a tire condition parameter different from a tread depth of the tire is detected as the at least one tire condition parameter. Furthermore, a reflectance of various surface areas of the tire is detected as the tire condition parameter, wherein the evaluation device - checks whether, in the circumferential direction of the tyre, during rotation of the tyre, there is a surface area whose reflectance value differs by more than a predetermined value from that of another surface area and / or whose reflectance value exceeds a predetermined limit, and, if this is the case, detects a metallic foreign body on or in the tyre; and / or - detects contamination of the profile recesses by comparing a stored reference profile pattern with the recorded reflectance pattern; and / or - on the basis of a stored reflectance reference value of the clean tire material of the tire, all areas of the tire that are contaminated and / or contain foreign bodies are determined if a reflectance analysis detects surface areas of the tire whose recorded reflectance values ​​deviate from the reflectance reference value of the clean tire.

[0027] The advantages mentioned with reference to the tire monitoring device according to the invention and its embodiments apply equally to the method according to the invention.

[0028] The invention also includes further developments of the method according to the invention that have features already described in connection with the further developments of the tire monitoring device according to the invention. For this reason, the corresponding further developments of the method according to the invention are not described again here.

[0029] An embodiment of the invention is described below. It shows: Fig. 1 is a schematic representation of a part of a motor vehicle with a tire monitoring device for monitoring a condition of a tire according to an embodiment of the invention; Fig. 2 is a graphical representation of a tire detected by the tire monitoring device during one rotation of the wheel for a tire with various defective conditions; Fig. 3 is a graphical representation of a reference curve measured by the tire monitoring device for calibration; and Fig. 4 a schematic representation of the mean distance profile of the distance between the tire surface 15 and the laser scanner 14 in the event of a tire deformation.

[0030] The exemplary embodiment explained below is a preferred embodiment of the invention. In the exemplary embodiment, the described components of the embodiment each represent individual, independently considered features of the invention, which also further develop the invention independently of one another and are thus also to be considered as components of the invention, either individually or in a combination other than that shown. Furthermore, the described embodiment can also be supplemented by further features of the invention already described.

[0031] In the figures, functionally identical elements are provided with the same reference numerals.

[0032] Fig. 1 shows a schematic representation of a part of a motor vehicle 10 with a tire monitoring device 12 for monitoring the condition of a tire 13 of the motor vehicle 10 according to an exemplary embodiment of the invention. For this purpose, the tire monitoring device 12 has a sensor device, which in this example is designed as a laser scanner 14. The laser scanner 14 is arranged at a position P0 spaced from the tire 13, and in particular in front of the tire 13 with respect to a forward direction of travel R, in which the motor vehicle 10 travels when traveling forward. This has the advantage that dirt and spray thrown off the tire 13 during forward travel only hit the measuring device, in this example the laser scanner 14, to a small extent or not at all.The laser scanner 14 is particularly designed to scan the surface 15 of the tire 13 in the circumferential direction U along a plurality of scan lines 16 running parallel to the wheel axis, particularly while the tire 13 is rotating as the motor vehicle 10 travels. This allows the laser scanner 14 to measure the contour and profile of the tire 13 in the circumferential direction U while the vehicle is traveling. If deviations from a known profile of the intact tire 13 are detected, for example with the aid of an algorithm, the driver can be informed of the tire damage and a tire replacement recommended. The algorithm is executed and the measurement signal acquired by the laser scanner 14 is evaluated by an evaluation device 17, which can be designed separately from the laser scanner 14 or integrated into it.The above-mentioned known profile can be stored, for example, as a reference in a memory of the evaluation device 17. This reference can also have been provided as an initial measurement by the laser scanner 14, for example, when mounting a new tire or when initializing the tire monitoring device 12 or upon its first use.

[0033] The laser scanner 14 thus continuously measures the distance profile of the distance between the laser scanner 14 and the surface 15 of the tire 13 in the circumferential direction U while driving. This allows the periodic pattern of the tire tread to be observed while driving over the circumference of the tire 13. By correlating the tread pattern observed in the past, i.e. the reference, with the currently measured tread, deviations and thus a multitude of different defective conditions of the tire 13 can be easily detected. Such defective conditions can be, for example, damage to the tread, embedded screws, foreign objects stuck in the recesses of the tread, such as stones, stones between twin tires, etc. The detection of these defective conditions of the tire 13 will now be explained using an example of Fig. 2 to Fig. 4 can be illustrated.

[0034] Fig. Fig. 2 shows a schematic graphic representation of the distance curve 18 of the distance A in the circumferential direction U measured by the laser scanner 13 during one rotation of the tire 13. This distance curve 18 measured in the circumferential direction U can be compared with a corresponding reference curve 19, which is shown in Fig. 3 shown. Fig. Figure 3 also shows a graphical representation of the reference curve 19 of the distance A in the circumferential direction U for the tire 13 in an intact or clean condition, i.e., without defects. This reference curve 19 can be recorded, as described above, by an initial measurement or calibration by the laser scanner 14 and stored in a memory. As shown in Fig. As can be seen in Figure 3, the reference curve 19 exhibits a periodic pattern due to the periodic tire profile. Deviations from the reference curve 19 can thus be easily detected by comparison. If such a deviation exceeds, for example, a predetermined limit, a defective tire condition can be detected. In addition, a distinction can optionally be made between different defective conditions of the tire 13. Examples include: Fig. 2 shows three different defective states Z1, Z2, Z3. A first defective state Z1 is a foreign body, such as a screw or a nail, which is stuck in a depression in the tread and protrudes beyond the elevations of the tread. Accordingly, at the point where a depression in the tread should actually be detected compared to the reference curve 19, a local elevation is detected instead. A second defective state Z2 represents damage to the tire tread, in which part of the tread, in particular an elevation in the tread, has broken off. Accordingly, compared to the reference curve 19, an irregular depression is detected at the point where this elevation in the tread should be located. Furthermore, a third defective state Z3 represents contamination of the tire surface 15.Compared to the reference profile 19, no depressions in the profile are therefore discernible in this area. The fact that this is not a worn profile, for example, can be detected by the fact that the distance A is not reduced relative to the position P0 of the sensor device 14 compared to a worn profile. Thus, contamination of the profile, for example, with snow, ice, or mud, can advantageously be detected. The laser scanner 14 can thus also be configured to detect that profile sections are filled with material by performing a contour analysis as described above. Corresponding information can then be displayed to the driver.

[0035] In addition to observing this distance profile 18, the reflectance of the tire surface 15 can also be measured by the laser scanner 14 across the tire surface 15 while the tire 13 is rotating. The rubber of the tire 13 has a different reflectivity than other materials, such as foreign bodies, dirt, or the like. This also makes it possible to distinguish whether, for example, a tread is worn down or whether the depressions in the tread are simply filled with dirt or other foreign bodies. This also makes it particularly easy to detect metallic foreign bodies, which have very high reflectivity. By contrast measurement of the reflectivity and the distance variance, i.e. the distance profile 18, across the tread width, the tread depth can also be continuously determined.

[0036] Furthermore, it can also be detected if there is an imbalance or deformation of the entire tire 13, which in Fig. 4. This schematic graphic shows the mean distance curve 20 of the distance A between the surface 15 and the laser scanner 14, or rather its position P0 in the circumferential direction U. As can be seen, the mean distance between the tire surface 15 and the laser scanner 14 varies periodically with the rotation time of the tire 13, which is the case when the tire 13 is unbalanced or deformed. This can be attributed, for example, to insufficient air pressure in the tire 13. This accordingly represents a fourth defective condition Z4, which can be detected by the tire monitoring device 12.

[0037] Furthermore, anomalies between the two tires of a dual-tire configuration, such as jammed objects, can be detected. If such a situation is detected, a warning can be issued to the driver, prompting them to immediately slow down and eliminate the hazard, for example, by removing the object.

[0038] As an alternative to the laser scanner 14 described above, the sensor device can also be designed as a radar sensor, and corresponding defect detection measures can be implemented accordingly. The radar sensor is particularly well suited for detecting metallic parts in the tire, such as embedded nails and screws.

[0039] Overall, the example shows how the invention, with the aid of sensory tire tread detection, can detect tire damage at a very early stage. The driver can be alerted to the situation using HMI (Human Machine Interface) elements, such as in the instrument cluster or on a mobile communications device or a handheld device, such as a smartphone. For this purpose, the tire monitoring device 12 can be designed to communicate with the corresponding HMI element. In automated vehicles, automatic tire tread detection can serve as an analogue to the legally required departure check by a human driver during manual driving. Advantageously, objects trapped between the twin tires of a truck can also be detected and reported to the driver.In addition to detecting tire damage, the tire's rotational speed can be determined, generating a signal comparable to wheel ticks in a passenger car. Simply detecting the tire tread pattern can be used to link contamination detection to a cleaning system. The cleaning system can be operated using high-pressure water spray or high-pressure air, even while driving. Thus, the tire monitoring device according to the invention and its configurations can provide tire condition monitoring that goes far beyond mere tread depth detection. List of reference symbols 10 motor vehicle 12 Tire monitoring device 13 tires 14 laser scanners 15 Tire surface 16 scan lines 17 Evaluation device 18 Distance progression 19 Reference history 20 mean distance progression A distance P0 Position of the laser scanner R Forward direction U circumferential direction Z1, Z2, Z3, Z4 poor condition

Claims

[1] Tire monitoring device (12) for arrangement on a motor vehicle (10) and for monitoring a condition of a tire (13), wherein the tire monitoring device (12) has at least one sensor device (14) which is designed to detect at least one tire condition parameter (18) in a proper installation position in which the sensor device (14) is located in a position (P0) spaced from the tire (13), and an evaluation device (17) which is designed to check, depending on the detected tire condition parameter (18), according to at least one predetermined criterion, whether a defective condition (Z1, Z2, Z3, Z4) of the tire (13) exists, wherein the tire monitoring device (12) is designed to detect, as the tire condition parameter (18), a tire condition parameter (18) different from a tread depth of the tire (13), characterized by , that the sensor device (14) is designed to detect a reflectance of different surface areas of the tire (13) as a tire condition parameter, wherein the evaluation device (17) is designed to - to check whether there is a surface area in the circumferential direction (U) of the tyre (13) during the rotation of the tyre (13) whose reflectance value differs by more than a predetermined value from that of another surface area and / or whose reflectance value exceeds a predetermined limit value, and if this is the case, to detect a metallic foreign body on or in the tyre (13); and / or - to detect contamination of the profile recesses by comparing a stored reference profile pattern with the recorded reflectance pattern; and / or - to determine, on the basis of a stored reflectance reference value of the clean tire material of the tire (13), all areas of the tire (13) that are contaminated and / or have foreign bodies if, during the reflectance analysis, surface areas of the tire (13) are detected whose recorded reflectance values deviate from the reflectance reference value of the clean tire (13). [2] Tire monitoring device (12) according to claim 1, wherein the sensor device (14) is designed as a laser scanner which is designed to scan at least one region of the tire surface (15) arranged in the circumferential direction (U) of the tire (13) along a plurality of scan lines (16) in the intended installation position. [3] Tire monitoring device (12) according to one of the preceding claims, wherein the evaluation device (17) is designed to determine at least one of the following defective states (Z1, Z3) of the tire (13) depending on the detected reflectance: - the presence of a foreign body in the tyre (13) and / or in the tyre tread and / or between two individual tyres of a twin tyre, - presence of dirt within tire tread recesses and / or on the tire surface (15). [4] Tire monitoring device (12) according to one of the preceding claims, wherein the sensor device (14) is designed to continuously detect a distance profile (18) of the distance (A) between the sensor device (14) and at least one region of the surface (15) of the tire (13) in the tire circumferential direction (U) as at least one further tire condition parameter (18) upon rotation of the tire (13) relative to the sensor device (14). [5] Tire monitoring device (12) according to claim 4, wherein the evaluation device (17) is designed to check, based on the distance profile (18), whether the tire (13) has a deformation in the circumferential direction (U), in particular whether the tire shape in the circumferential direction (U) deviates from a circular shape by more than a predetermined amount. [6] Tire monitoring device (12) according to one of the preceding claims 4 or 5, wherein the evaluation device (17) is designed to compare the distance profile (18) with a reference profile (19) and, depending on a result of the comparison, to determine at least one of the following defective states (Z1, Z2, Z3) of the tire (13): - local damage to the tyre (13); - the presence of a foreign body in the tyre (13) and / or in the tyre tread and / or between two individual tyres (13) of a twin tyre; - presence of dirt within the tire tread and / or on the tire surface (15). [7] Tire monitoring device (12) according to one of the preceding claims, wherein the tire monitoring device (12) is designed to determine a rotational speed of the tire (13). [8] Motor vehicle (10) with a tire monitoring device (12) according to one of the preceding claims. [9] Motor vehicle (10) according to claim 8, wherein the sensor device (14) for monitoring a condition of a tire (13) of the motor vehicle (10) is arranged in a position (P0) spaced from the tire (13) which is located in front of the tire (13) when the motor vehicle is traveling forward in the direction of travel (R). [10] Method for monitoring a condition of a tire (13), wherein at least one tire condition parameter (18) is detected by means of a sensor device (14) spaced from the tire (13), and depending on the detected tire condition parameter (18) it is checked according to at least one predetermined criterion whether a defective condition (Z1, Z2, Z3, Z4) of the tire (13) exists, wherein a tire condition parameter (18) different from a tread depth of the tire (13) is detected as the at least one tire condition parameter (18), characterized by , that a reflectance of different surface areas of the tire (13) is detected as a tire condition parameter, wherein the evaluation device (17) - checks whether there is a surface area in the circumferential direction of the tire (13) during the rotation of the tire (13) whose reflectance value differs by more than a predetermined value from that of another surface area and / or whose reflectance value exceeds a predetermined limit value, and if this is the case, detects a metallic foreign body on or in the tire (13); and / or - detects contamination of the profile recesses by comparing a stored reference profile pattern with the recorded reflectance pattern; and / or - on the basis of a stored reflectance reference value of the clean tire material of the tire (13), all areas of the tire (13) that are contaminated and / or have foreign bodies are determined if, during a reflectance analysis, surface areas of the tire (13) are detected whose recorded reflectance values deviate from the reflectance reference value of the clean tire (13).

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