Method for detecting camber errors of the vehicle tires of a vehicle system

Abstract

The invention relates to a method for detecting camber errors of the vehicle tires of a vehicle system, comprising: i) a system vehicle, ii) at least one system vehicle tire (10) arranged on the system vehicle, with a sensor unit (12) for detecting the lateral acceleration, and iii) at least one electronic data processing device, comprising the method steps: a) driving the system vehicle and detecting one or more test values ​​of the lateral acceleration at one or more test times at which the sensor unit (12) is located outside the circular segment of the system vehicle tire (10) bounded by the ground contact area (16), and b) comparing the test values ​​with calibration values ​​of the lateral acceleration using the electronic data processing device, whereby a camber error of the system vehicle tire (10) is detected.if the deviation between the recorded test values ​​and the previously determined calibration values ​​lies outside a predetermined tolerance.

Description

[0001] The invention relates to a method for detecting camber errors of the vehicle tires of a vehicle system and a vehicle system suitable for this purpose.

[0002] In light of the steady increase in global road traffic and the associated rise in traffic accidents, driving safety has become increasingly important in recent years. One vehicle component that plays a crucial role in driving safety is the tires, which are specifically designed to suit expected environmental conditions in order to optimize handling and braking performance.

[0003] In addition to the type of rubber compound used and the choice of the optimal tire profile, the correct alignment of the vehicle tires on the vehicle is of particular importance with regard to the driving safety-relevant properties of the vehicle tires and their durability.

[0004] Vehicle tires should normally be operated without camber errors, that is, with the axis in a defined plane perpendicular to the Earth's gravitational field, with angles of about 1° to 2° being common in this respect.

[0005] Incorrect camber can lead to undesirably high or uneven tire wear. Therefore, it is desirable to detect such camber errors early. Nowadays, camber accuracy is usually only checked and corrected during maintenance or checkups at workshops. However, this does not allow for the early detection of camber errors, which is generally considered a disadvantage.

[0006] The primary objective of the present invention was to eliminate or at least reduce the disadvantages of the prior art.

[0007] In particular, the object of the present invention was to provide a method for detecting camber errors in a vehicle's tires as early as possible, especially during vehicle operation. In this respect, it was an object of the present invention that the method provided should enable early warnings to be issued to the driver in order to counteract any occurring camber error at an early stage. This should make it possible to increase driving safety and improve the durability of vehicle tires, particularly with regard to the occurrence of uneven wear.

[0008] It was an object of the present invention that the specified method should not only be executable in a time- and cost-efficient manner, but that it should ideally also be particularly easy to integrate into existing vehicle systems, so that the need for additional components can be minimized.

[0009] Furthermore, it was an object of the present invention to provide an advantageous vehicle system which is designed for the execution of the method according to the invention and can therefore be operated in a particularly safe manner, since any camber error that may occur in the vehicle's tires can be detected at an early stage.

[0010] The inventors of the present invention have now found that the problems described above can be solved if, in a vehicle system consisting of a system vehicle and sensor-equipped pneumatic tires arranged thereon, which include electronic sensor units arranged on their inner tire layer for detecting lateral acceleration, calibration values ​​of the lateral acceleration are determined with the electronic sensor units during a calibration period in which the camber of the vehicle tires corresponds to a desired initial value, and these calibration values ​​are compared with subsequently acquired test values ​​of the lateral acceleration, which are acquired during the operation of the system vehicle, whereby a camber error can be detected by the fact that the lateral acceleration at the test times is outside a predetermined tolerance, as defined in the claims.

[0011] This advantageously allows the acceleration sensor, already present in many modern pneumatic tires and capable of detecting both the radial and lateral acceleration components, to be used to detect camber errors in appropriately equipped tires. This enables early detection of camber errors even during vehicle operation. Camber errors, or incorrect camber values ​​that fall outside the ranges specified by the vehicle manufacturer, manifest themselves in the fact that the lateral component of the acceleration values ​​detected by the electronic sensor units...whose distribution deviates from that recorded during the calibration period, whereby this value will increase in most cases with an increasing fall, since the electronic sensor unit is also accelerated in a lateral direction due to the fall in a way that does not occur, or not to the same extent, in an ideal fall.

[0012] The aforementioned problems are thus solved by the subject matter of the invention as defined in the claims. Preferred embodiments of the invention are described in the dependent claims and the following descriptions.

[0013] Such embodiments, which are hereinafter referred to as preferred, are combined in particularly preferred embodiments with features of other embodiments referred to as preferred. Combinations of two or more of the embodiments referred to below as particularly preferred are therefore especially preferred. Also preferred are embodiments in which a feature of one embodiment, referred to as preferred to any degree, is combined with one or more further features of other embodiments, which are referred to as preferred to any degree. Features of preferred vehicle systems result from the features of preferred methods.

[0014] Particularly preferred embodiments of the invention are disclosed in the exemplary embodiments. Particularly preferred embodiments of the invention have two or more, preferably three or more, and most preferably four or more, of the preferred features of the invention disclosed below, which are also implemented in the exemplary embodiments.

[0015] The invention relates to a method for detecting camber errors of the vehicle tires of a vehicle system, comprising: i) a system vehicle, ii) at least one system vehicle tire arranged on the system vehicle, comprising an electronic sensor unit arranged in the system vehicle tire for detecting lateral acceleration and an electronic transmitter unit for sending information in a wireless data transmission method, and iii) at least one electronic data processing device, comprehensively the procedural steps: a) Driving the system vehicle and recording one or more test values ​​of the lateral acceleration with the electronic sensor unit at one or more test times, wherein the electronic sensor unit is located outside the circular segment of the system vehicle tire bounded by the ground contact area at the test times, and b) Comparison of the recorded lateral acceleration test values ​​with one or more previously determined lateral acceleration calibration values ​​using the electronic data processing device, whereby a camber error of the system vehicle tire is detected if the deviation between the recorded test values ​​and the previously determined calibration values ​​is outside a predetermined tolerance, wherein one or more calibration values ​​of the lateral acceleration are determined in a calibration period prior to process step a) on the system vehicle tire with the electronic sensor unit at one or more calibration measurement times, wherein the system vehicle tire is either unloaded at the calibration measurement times or wherein the electronic sensor unit is located outside the circular section of the system vehicle tire defined by the ground contact area at the test times.

[0016] The method according to the invention is suitable in principle for detecting camber errors in the tires of different system vehicles, provided these vehicles are equipped with corresponding sensor-equipped system vehicle tires. An exemplary method according to the invention is described in which the system vehicle is a passenger car or a commercial vehicle, preferably a commercial vehicle, in particular a truck. Due to the advantageous influence on driving safety and the durability of the vehicle tires, a method according to the invention is preferred in which the system vehicle comprises two or more, preferably four or more, system vehicle tires.

[0017] The method according to the invention is carried out on a vehicle system, which is to be understood as an assembly of various components. This vehicle system comprises, firstly, a system vehicle with at least one sensor-equipped system vehicle tire and at least one electronic data processing device, wherein the data processing device, in accordance with the understanding of those skilled in the art, is used at least in the implementation of method step b), and wherein it can, in particular, execute a corresponding computer program product which contains instructions that cause it to execute the corresponding step.

[0018] In other words, the electronic data processing device is designed to compare test values ​​of lateral acceleration recorded during the journey of the system vehicle with the electronic sensor unit, which were recorded at one or more test times when the electronic sensor unit was outside the circular segment of the system vehicle tire defined by the ground contact area, with one or more previously determined calibration values ​​of lateral acceleration which are stored on a storage unit of the electronic data processing device, and to detect a camber error of the system vehicle tire if the deviation between the recorded test values ​​and the previously determined calibration values ​​is outside a predetermined tolerance.

[0019] A preferred method according to the invention is wherein the electronic data processing device is part of the system vehicle, preferably the on-board computer or an additional device arranged on the system vehicle, or wherein the electronic data processing device is separate from the system vehicle, preferably a server or a cloud, wherein the electronic data processing device is particularly preferably the central data processing device of a fleet management system.

[0020] The system vehicle tire incorporates an internal electronic sensor unit for detecting lateral acceleration, preferably time-dependent lateral acceleration. In accordance with established technical understanding, lateral acceleration is the acceleration component in the direction orthogonal to both the radial and circumferential directions of the system vehicle tire. In other words, at least in the absence of camber errors, it is the direction of rotation around the axis of the tire.

[0021] Corresponding sensor units are known in principle from the prior art and are commercially available from various suppliers. A preferred method is one according to the invention, wherein the electronic sensor unit is selected from the group consisting of biaxial and triaxial accelerometers, preferably from the group consisting of triaxial accelerometers. Biaxial accelerometers are particularly suitable for detecting lateral acceleration when at least one of the axes points in the lateral direction.The use of multi-axial acceleration sensors not only has the advantage that additional valuable acceleration data can be recorded, but also allows, in particular, the detection of the passage through the ground contact area via the measurement of radial acceleration, and thus the control of the measurement data acquisition in the method according to the invention, as will be explained in more detail below.

[0022] Although it is conceivable in principle to carry out the methods according to the invention with a sensor-equipped solid rubber tire, it is preferred for essentially all embodiments if the system vehicle tire is a pneumatic tire in which the electronic sensor unit is arranged inside the inner tire layer. A preferred method according to the invention is one in which the system vehicle tire is a pneumatic tire comprising a radially outer tread and a radially inner tire layer, wherein the electronic sensor unit is arranged on the inner tire layer.

[0023] The electronic sensor unit of the system vehicle tire is preferably located inside the tire in the area of ​​the tire crown. The term "tire crown" is clear to those skilled in the art and refers to the radially outer, circumferential part of the system vehicle tire as a whole. The tire crown includes, in particular, the parts of the tread intended for road contact and the tire components located further inwards in the radial direction, especially the reinforcement layers arranged beneath the tread, the tire carcass and the inner tire layer, as well as the tire shoulders immediately adjacent to the tread, which undergo significant deformation during driving.The arrangement in the area of ​​the tire crown, particularly below the tread on the inner layer of a vehicle tire, has the advantage that, due to the large distance from the axis of rotation, changes in tire camber can be more easily detected via lateral acceleration. Furthermore, this positioning, especially when using multi-axial acceleration sensors, allows the detection of the movement across the contact patch from the time-dependent radial acceleration and enables conclusions to be drawn about the wear of the system vehicle tires from changes over time, as is generally described in the prior art.

[0024] The further the electronic sensor unit is positioned towards the tire crown, the more strongly the lateral acceleration measurements are influenced by the deformation of the system vehicle tire as it passes over the contact patch. When the electronic sensor unit undergoes this deformation, lateral accelerations can occur that are not attributable to a camber error. Accordingly, such deformations can adversely affect the method according to the invention. For this reason, the method according to the invention is carried out in such a way that the lateral acceleration test values ​​are recorded at test times when the electronic sensor unit, during its rotational movement, is outside the area of ​​significant deformation.Since, in addition to the immediate tire crown, which forms the contact patch, the adjacent tire sidewalls are also deformed, the present invention defines that the electronic sensor unit is located outside the circular segment of the system vehicle tire bounded by the contact patch at the test times. This circular segment, in accordance with the skilled person's understanding, is the three-dimensional area of ​​the system vehicle tire spanned by the contact patch and the axis of rotation of the system vehicle tire. For the sake of simplicity, the present invention also refers to a circular segment even if, strictly speaking, the system vehicle tire does not form a perfect circle as a result of the deformation.

[0025] According to the inventors, to obtain the most meaningful test results, it is preferable to use test values ​​for the inventive method that are located as far away as possible from the ground contact area. A preferred method is one in which the electronic sensor unit is located at the test times in the circular segment that comprises the 75%, preferably the 50%, and most preferably the 25% of the system vehicle tire that is furthest from the circular segment defined by the ground contact area, relative to its circumference. An additionally or alternatively preferred method is one in which the electronic sensor unit is located at the test times in the half, preferably the third, and most preferably the quarter of the system vehicle tire opposite the ground contact area.

[0026] When recording time-dependent data of lateral acceleration, it is advantageous to use the time-dependent acceleration values ​​in which the electronic sensor unit was at the corresponding position.

[0027] In practice, a person skilled in the art can identify the position of the electronic sensor unit in various ways. If its position within the system vehicle tire is known, it can, for example, be deduced from the rotational position of the system vehicle tires. Additionally or alternatively, other detection devices can be used to draw conclusions about the position of the electronic sensor unit.

[0028] A particularly preferred embodiment arises, however, when the electronic sensor unit can also detect radial acceleration and is positioned sufficiently close to the tire crown to detect the deformation of the system vehicle tire in the contact patch via radial acceleration, as is the case, for example, when the radial acceleration is used to infer tire wear. In this case, the radial acceleration allows for the simple identification of the times when the electronic sensor unit passes through the contact patch. By appropriately comparing the time-dependent measured values, only those lateral acceleration measurements can be efficiently used where the corresponding radial accelerations indicate that the electronic sensor unit is at the desired distance from the contact patch.A preferred method according to the invention is therefore one in which, in process step a), the radial acceleration is additionally recorded, wherein the selection of the test values ​​used for comparison with the previously determined calibration values ​​depends on the recorded radial acceleration at the measurement times.

[0029] In addition to the electronic sensor unit, the system vehicle tire includes an electronic transmitter unit. The electronic transmitter unit serves to transmit the information acquired or determined by the electronic sensor unit to a receiver located outside the system vehicle tire. A method according to the invention is relevant for essentially all embodiments, wherein the wireless data transmission method is selected from the group consisting of radio methods, for example Bluetooth or using a frequency of 433 MHz.

[0030] With a view to the cost-efficiency of manufacturing corresponding system vehicle tires, the inventors consider it preferable if the electronic sensor unit and the electronic transmitter unit are integrated into a single component. This is advantageous within the manufacturing process of the system vehicle tire, since only a single component needs to be installed, thus advantageously eliminating the need for further electronic components in the system vehicle tire. A method according to the invention is therefore preferred, wherein the electronic sensor unit and the electronic transmitter unit are integrated into a common component.

[0031] Additionally or alternatively, the inventors consider it preferable if the electronic transmitting unit is also configured to receive information via wireless data transmission. This advantageously enables two-way communication, for example between the system vehicle and the system vehicle tires, for instance to update the programming of the electronic transmitting unit. Therefore, an additionally or alternatively preferred method according to the invention is one in which the electronic transmitting unit is an electronic transmitting and receiving unit capable of receiving information via wireless data transmission.

[0032] A preferred method according to the invention is one in which the electronic sensor unit is configured to record the test values ​​at predetermined intervals, for example hourly, preferably as a time-dependent lateral acceleration, in which the lateral acceleration is recorded for a specific period, for example over a predetermined time or over a predetermined number of revolutions of the system vehicle tire. It is understood by those skilled in the art that the signal can be recorded digitally, so that the signal can consist of many successive measurement points and need not represent a continuous curve. Accordingly, the method according to the invention can be carried out at predetermined intervals, for example, to regularly confirm the correct position of the system vehicle tires.This allows the method according to the invention to be carried out in a particularly energy-efficient manner. The inventors propose that the predetermined time intervals should not be chosen too short, for example, not shorter than hourly, so that the electronic sensor unit can be designed to be particularly durable. The energy efficiency of tire sensor units is particularly relevant with regard to their service life, since such sensor units often have only limited energy resources. Excessive use of these energy resources by sensor units installed in vehicle tires is therefore undesirable in most cases. In an alternative embodiment, the method according to the invention is only carried out on demand, for example, by a transmitted trigger signal. This allows the energy consumption to be reduced even further.A preferred method according to the invention is one in which method step a) is carried out as a result of an external trigger signal received by the electronic sensor unit. Additionally, it is possible to link the transmission of the trigger signal to specific events, for example, reaching a predetermined distance.

[0033] In process step b), the test values ​​for lateral acceleration recorded as described above are compared with one or more previously determined calibration values ​​for lateral acceleration, which were recorded on the same system vehicle tire. This comparison is performed using the electronic data processing device and serves to detect any camber error of the system vehicle tire.

[0034] For this purpose, the calibration values ​​of the lateral acceleration are used, which represent the lateral acceleration values ​​that were recorded in the system vehicle tires with the electronic sensor units at an earlier time, when the orientation of the system vehicle tires thus corresponded to a previous initial state. Those skilled in the art understand that the calibration values ​​are preferably recorded at a time when there is no camber error, i.e., when the vehicle tires are rotating precisely in the desired orientation, for example, immediately after a visit to a workshop. In this reference orientation, from which the calibration values ​​are determined, the lateral acceleration will vary within a predetermined range and, in particular, will almost disappear when the axis of rotation is perfectly horizontal, i.e., without any camber value.

[0035] The totality of the calibration values ​​can be understood as a kind of zero line, whereby a camber error or camber detection is identified when the lateral acceleration recorded in the test values ​​shows an excessive deviation from this zero line. This occurs because, due to the increased camber, the sensor is also accelerated laterally in a way that leads to increasing lateral acceleration contributions. Within the scope of the present invention, this is expressed by the fact that the camber error of the system vehicle tire is detected when the deviation between the recorded test values ​​and the previously determined calibration values ​​lies outside a predetermined tolerance.

[0036] In addition to comparing the absolutely determined lateral acceleration, for example via its maximum or minimum values, the deviation between the recorded test values ​​and the previously determined calibration values ​​can also be determined using other parameters, for example by comparing and evaluating the distribution width. While the distribution width should be approximately 0 for a tire running perfectly vertically, the distribution width increases with additional camber. For some applications, a method according to the invention is preferred in which a camber error of the system vehicle tire is detected if the deviation in the distribution width between the recorded test values ​​and the previously determined calibration values ​​lies outside a predetermined tolerance.The person skilled in the art adjusts the predetermined tolerance to the relevant application case, whereby in safety-critical applications, rather small tolerances in the deviation of the lateral acceleration values ​​from the calibration values ​​are advantageous, while for applications in which a comparatively large number of external influencing factors are to be expected, for example in off-road applications, it is advisable to set a somewhat higher tolerance in order to avoid false alarms.

[0037] The expert understands that the calibration values ​​of the lateral acceleration used for the comparison should expediently correlate with an orientation of the vehicle tire that corresponds to the desired specifications, so that a deviation from the specification can be detected by comparison with the test values.

[0038] The inventors have found that corresponding calibration values ​​can be obtained in two different ways. A particularly efficient method involves determining the calibration values ​​in a state where the vehicle tires are unloaded. This can be done, for example, on a separate machine, such as during tire balancing, or with the vehicle raised on a lift. The expression "unloaded" at the time of calibration is clear to those skilled in the art and means that the tires are essentially undeformed and, in particular, do not form a contact patch with the ground.The advantage of this design lies in the fact that, in the absence of a ground contact area where lateral acceleration values ​​could be misleading, it is possible in principle to detect calibration measurements over the entire rotation of the electronic sensor units in the system vehicle tire. Therefore, in many cases, a method according to the invention is preferred in which the system vehicle tire is unloaded at the calibration times, the system vehicle is raised by a lifting device so that the system vehicle tires have no ground contact, or the system vehicle tire is rotated on a rotating device separate from the vehicle, preferably on a rotating device separate from the vehicle.

[0039] The design of the unloaded determination of the calibration values ​​using a lifting platform advantageously allows the inventive method to be integrated into the usual maintenance work on system vehicles and, in particular, enables the inventive method to be carried out directly on the system vehicle immediately after optimal adjustment of the tire camber in order to record the calibration values, which can then be used to verify the correct tire camber during subsequent operation. The alternative design, in which the calibration values ​​are determined on a rotating device separate from the system vehicle, offers other advantages. In particular, this makes it possible to adjust the tire camber with greater precision, since separate rotating devices are often easier to control in this respect.Furthermore, this design allows tire manufacturers and / or tire changing companies to efficiently detect the necessary calibration values ​​even before the system vehicle tires are fitted to the system vehicle.

[0040] In an alternative embodiment to the unloaded determination of the calibration measurements, the determination of the calibration measurements can also be carried out while the system vehicle is driving, whereby in this case, analogous to the above considerations regarding the deformation of the tire contact patch, measurements should again be taken in such parts of the tire in which the electronic sensor unit is influenced as little as possible by the possible deformation in the area of ​​the ground contact patch, whereby the same statements regarding preferred positions apply in this respect.

[0041] The person skilled in the art understands that, for the calibration process provided for in the invention, it is necessary that the calibration values ​​be transmitted to the electronic data processing device or be available to it in another form. When determining the calibration measurements during ongoing driving operation, the electronic data processing device can advantageously simply store the lateral acceleration measurements transmitted by the electronic sensor units as calibration measurements.In embodiments where the calibration measurements are taken on a system vehicle tire separate from the system vehicle, it is advantageous to design the electronic sensor units such that they store the calibration measurements in an internal memory unit and are configured to transmit the calibration measurements stored on the memory unit to the electronic data processing device via wireless data transmission. A preferred method according to the invention is therefore one in which the one or more calibration measurements are stored on a memory unit of the electronic sensor unit, and the vehicle system is configured so that the one or more calibration measurements can be transmitted from the electronic sensor unit to the electronic data processing device.

[0042] The inventors propose that it is advantageous to couple the calibration process, i.e., the acquisition of new calibration values ​​for lateral acceleration, to an initiation signal with which the calibration can be initiated. A corresponding initiation signal can be transmitted to the electronic sensor units via wireless data transmission to cause them to acquire the lateral accelerations and store them as calibration measurements either on an internal memory unit and / or transmit them to the electronic data processing device. A preferred method according to the invention is one in which the one or more calibration values ​​for lateral acceleration are determined within a calibration period as a result of an external initiation signal.

[0043] In addition to the aforementioned aspect that the passage of the electronic sensor unit across the contact patch can lead to lateral acceleration components not caused by incorrect tire camber, the inventors have also identified further influencing factors. Specifically, the inventors have found that particularly advantageous and reliable lateral acceleration measurements are obtained when the vehicle is traveling straight ahead. This prevents system vehicle tires, especially those located on the steering axles, from experiencing lateral acceleration components attributable to the steering movement and any resulting tire misalignment, rather than to incorrect tire camber.In this context, a method according to the invention is preferred in which the vehicle is in a straight-ahead position at the test times, wherein the angle between the longitudinal axis of the vehicle and the direction of rotation of the vehicle tires is 5° or less, preferably 2° or less, preferably 1° or less, and most preferably essentially 0°.

[0044] In other words, a method according to the invention is preferred in which one or more steering information signals from the system vehicle are acquired, which correlate with the orientation of the system vehicle's tires relative to the longitudinal axis of the system vehicle, wherein the steering information signals lie within a predetermined value range at the test times. If the calibration values ​​are also to be acquired during the vehicle's operation, the above statements regarding the test times apply accordingly to the calibration measurement times, which should also preferably be during straight-ahead driving. It is particularly preferred to apply the corresponding straight-ahead driving criterion both for acquiring the test values ​​and for determining the calibration values.

[0045] Performing the comparison of the recorded test values ​​with the calibration values ​​across the distribution range, which is described in more detail above, has the advantage of being less dependent on the absolute values ​​of the lateral acceleration. The portion of the acceleration attributable to the lateral component can depend on the total acceleration experienced, meaning that even with very high total acceleration values, high lateral acceleration contributions can be recorded even if the tire camber is still within the tolerance range. If the comparison is to be performed using absolute deviations, it is therefore advisable to consider the total acceleration experienced by the system vehicle tires.For this purpose, the test values ​​can be correlated with speed information that correlates with the rotational speed or acceleration in order to compare the deviation with calibration values ​​that were recorded with comparable speed information. A preferred method according to the invention is therefore one in which speed information is recorded at the test times, speed information is recorded at the calibration measurement times that is assigned to the specific calibration values, and the recorded test values ​​are compared with calibration values ​​whose stored speed information deviates from the speed information recorded for the test values ​​by no more than a predetermined tolerance value.A method according to the invention is particularly preferred, wherein the speed information includes information about the vehicle speed, the rotational speed of the system vehicle tires and / or the total acceleration experienced by the electronic sensor units.

[0046] The invention also relates to a vehicle system for use in the inventive method, comprising: i) a system vehicle, ii) at least one system vehicle tire arranged on the system vehicle, comprising an electronic sensor unit arranged in the system vehicle tire for detecting lateral acceleration and an electronic transmitter unit for sending information in a wireless data transmission method, and iii) at least one electronic data processing device, wherein the electronic data processing device is configured to compare test values ​​of lateral acceleration recorded during the journey of the system vehicle with the electronic sensor unit, which were recorded at one or more test times when the electronic sensor unit was located outside the circular segment of the system vehicle tire bounded by the ground contact area, with one or more previously determined calibration values ​​of lateral acceleration which are stored on a storage unit of the electronic data processing device and to detect a camber error of the system vehicle tire if the deviation between the recorded test values ​​and the previously determined calibration values ​​is outside a predetermined tolerance.

[0047] The invention and preferred embodiments of the invention are explained and described in more detail below with reference to the accompanying figure. The figure shows: Fig. 1 A schematic cross-sectional representation through a system vehicle tire for use in the method according to the invention.

[0048] Fig. Figure 1 shows a system vehicle tire 10 as it can be used in a method according to the invention. In the example shown, the system vehicle tire 10 is designed as a pneumatic tire with an inner tire layer 18 and is arranged on a system vehicle, which is not shown for the sake of clarity, and whose on-board computer provides the electronic data processing device for carrying out process step b) of the method according to the invention.

[0049] Below the tread 20 intended for road contact, an electronic sensor unit 12 is mounted on the inner tire layer 18, radially directly below the tread 20. This sensor unit and the electronic transmitter unit 14 are integrated into a single component. The electronic transmitter unit 14 is designed to transmit acceleration values ​​detected by the electronic sensor unit 12 to the on-board computer located in the vehicle via Bluetooth.

[0050] The electronic sensor unit 12 is, in the example shown, the Fig. 1. Designed as a 3-axial accelerometer, in which the radially pointing z-axis and the circumferentially pointing x-axis are in the Fig. 1 are entered, while the y-axis, which is orthogonal to it, points in the direction of the viewer.

[0051] In the lower part of the Fig. Figure 1 shows a significantly exaggerated representation of the ground contact area 16, in which the system vehicle tire 10, loaded by the weight of the system vehicle, is deformed. The circular segment of the system vehicle tire 10 bounded by the ground contact area 16 is clearly indicated by dashed lines, and the upper half of the system vehicle tire 10, opposite the ground contact area 16, is delineated by a dotted line.

[0052] The in Fig. The system vehicle tire 10 shown is designed so that, in the inventive method, numerous test values ​​of the lateral acceleration are recorded by the electronic sensor unit 12 during the journey of the system vehicle. The test times, which form the basis for the subsequent comparison, are selected such that the electronic sensor unit 12 is located in the half of the system vehicle tire 10 opposite the ground contact area 16 at these test times. Furthermore, in the subsequent comparison, the electronic data processing device only uses test values ​​from test times that correspond to straight-ahead driving based on steering information derived from the vehicle control system.

[0053] The lateral acceleration test values ​​recorded in this way are compared via the system vehicle's on-board computer with previously determined calibration values ​​for lateral acceleration stored there, specifically by comparing the distribution range of the lateral acceleration. A deviation between the distribution ranges that lies outside a predetermined tolerance can advantageously indicate the presence of a camber error in the system vehicle's tire, whereupon appropriate measures can be initiated, such as issuing a warning signal or arranging maintenance work to correct the tire camber.

[0054] The calibration values ​​used for the adjustment are shown in the example of the Fig.1 directly on the system vehicle tire 10 arranged on the system vehicle, namely immediately after setting the correct tire camber, wherein the corresponding calibration measurement times are chosen in analogy to the test times so that these take place in phases of straight-ahead driving at times when the electronic sensor unit 12 is as far away as possible from the ground contact surface 16.

[0055] By advantageously using a 3-axial acceleration sensor, which can also detect radial acceleration, the temporal development of the radial acceleration can be used to detect the passage of the electronic sensor unit 12 through the ground contact surface 16 and, depending on this, to identify the correct test times or calibration measurement times. Reference symbol list 10 system vehicle tires 12 electronic sensor unit 14 electronic transmitting unit 16 Ground contact area 18 Tire inner layer 20 treads

Claims

[1] Method for detecting camber errors of the vehicle tires of a vehicle system, comprising: i) a system vehicle, ii) at least one system vehicle tire (10) arranged on the system vehicle, comprising an electronic sensor unit (12) arranged in the system vehicle tire (10) for detecting the lateral acceleration and an electronic transmitter unit for transmitting information in a wireless data transmission method, and iii) at least one electronic data processing device, comprehensively the procedural steps: a) Driving the system vehicle and recording one or more test values ​​of the lateral acceleration with the electronic sensor unit (12) at one or more test times, wherein the electronic sensor unit (12) is located outside the circular segment of the system vehicle tire (10) defined by the ground contact area (16) at the test times, and b) Comparison of the recorded lateral acceleration test values ​​with one or more previously determined lateral acceleration calibration values ​​using the electronic data processing device, whereby a camber error of the system vehicle tire (10) is detected if the deviation between the recorded test values ​​and the previously determined calibration values ​​is outside a predetermined tolerance, wherein one or more calibration values ​​of the lateral acceleration are determined in a calibration period prior to process step a) on the system vehicle tire (10) with the electronic sensor unit (12) at one or more calibration measurement times, wherein the system vehicle tire (10) is either unloaded at the calibration measurement times or wherein the electronic sensor unit (12) is located outside the circular section of the system vehicle tire (10) defined by the ground contact area (16) at the test times. [2] Method according to claim 1, wherein the electronic sensor unit (12) is selected from the group consisting of biaxial accelerometers and triaxial accelerometers. [3] Method according to one of claims 1 or 2, wherein the system vehicle tire (10) is a vehicle pneumatic tire comprising a radially outer tread (20) and a radially inner tire layer (18), wherein the electronic sensor unit (12) is arranged on the tire layer (18). [4] Method according to one of claims 1 to 3, wherein the electronic sensor unit (12) is located at the test times in the circular segment which comprises the 75% of the system vehicle tire (10) that is furthest away from the circular segment bounded by the ground contact area (16) in relation to the circumference. [5] Method according to one of claims 1 to 4, wherein the electronic sensor unit (12) is located in the half of the system vehicle tire (10) opposite the ground contact area (16) at the test times. [6] Method according to one of claims 1 to 5, wherein in method step a) the radial acceleration is additionally recorded, wherein the selection of the test values ​​used for comparison with the previously determined calibration values ​​is made depending on the radial acceleration recorded at the measurement times. [7] Method according to any one of claims 1 to 6, wherein a camber error of the system vehicle tire (10) is detected when the deviation in the distribution width between the recorded test values ​​and the previously determined calibration values ​​is outside a predetermined tolerance. [8] Method according to any one of claims 1 to 7, wherein the vehicle is in a straight-ahead position at the test times, wherein the angle between the longitudinal axis of the vehicle and the direction of rotation of the system vehicle tires (10) is 5° or less. [9] Method according to any one of claims 1 to 8, wherein one or more calibration values ​​of the lateral acceleration are determined in a calibration period as a result of an external initiation signal. [10] Vehicle system for use in a method according to any one of claims 1 to 9, comprising: i) a system vehicle, ii) at least one system vehicle tire (10) arranged on the system vehicle, comprising an electronic sensor unit (12) arranged in the system vehicle tire (10) for detecting the lateral acceleration and an electronic transmitter unit (14) for transmitting information in a wireless data transmission method, and iii) at least one electronic data processing device, wherein the electronic data processing device is configured to compare test values ​​of lateral acceleration recorded during the journey of the system vehicle with the electronic sensor unit (12), which were recorded at one or more test times when the electronic sensor unit (12) was located outside the circular segment of the system vehicle tire (10) defined by the ground contact area (16), with one or more previously determined calibration values ​​of lateral acceleration which are stored on a storage unit of the electronic data processing device and to detect a camber error of the system vehicle tire (10) if the deviation between the recorded test values ​​and the previously determined calibration values ​​is outside a predetermined tolerance.

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