Method for adjusting a sensor unit in a vehicle pneumatic tire

Abstract

The invention relates to a method for adjusting an electronic sensor unit (10) in a vehicle tire (12) using an electronic data processing device, wherein the vehicle tire (12) comprises an electronic sensor unit (10) arranged below the tread on the inner layer (14) of the tire, comprising: i) an acceleration sensor, and ii) an electronic filter unit, with at least one cutoff frequency, comprising the method steps: a1) determining radius information of the sensor unit (10) during the rotation of the vehicle tire (12) using an electronic data processing device, wherein the radius information is the distance of the sensor unit (10) from the axis of rotation of the vehicle tire (12) in the radial direction,and b1) changing the cutoff frequency of the electronic filter unit as a function of the radius information using the electronic data processing device, and additionally or alternatively the process steps: a2) determining speed information during the rotation of the vehicle tire (12) using an electronic data processing device, wherein the speed information is the rotational speed of the vehicle tire, and b2) changing the cutoff frequency of the electronic filter unit as a function of the speed information using the electronic data processing device.

Description

[0001] The invention relates to a method for adjusting an electronic sensor unit in a pneumatic vehicle tire and to a pneumatic vehicle tire which is suitable for carrying out the method.

[0002] Advancing technological development and increasing digitalization are particularly affecting the field of automotive technology and vehicle tires. There is continued interest in continuously recording performance data from the components used in vehicles, for example, to continuously monitor performance and operational reliability. Information that can be monitored for vehicle tires includes, for example, tire pressure, tire temperature, or the acceleration experienced by the vehicle tire during operation.

[0003] Particularly valuable information about the condition of vehicle tires or their monitoring can be obtained, for example, through the use of acceleration sensors. The data thus obtained can be used, for example, to draw conclusions about the remaining tread depth of the tire tread, as disclosed, for example, in DE 102015216212 A1. Further prior art is disclosed, for example, in WO 2021192474 A1, US 9669664 B2, CN 107727042 A, US 20210208029 A1, or US 20200056983 A1.

[0004] The acceleration data measured by acceleration sensors positioned in vehicle pneumatic tires are obtained as a time series of acceleration values, whereby the corresponding signal can be processed by an electronic data processing device, for example to carry out the calculations disclosed above. Carrying out the measurement during driving operation imposes special requirements on the signal processing. The mechanical loads experienced by the acceleration sensor arranged in the vehicle pneumatic tire during driving operation result in the detected time-dependent acceleration having contributions from frequencies that can complicate the evaluation of the acceleration data or reduce the accuracy of the evaluation. For this reason, it is often necessary for a reliable evaluation of the specific signals that the input signal received from the acceleration sensors, iethe time series of acceleration values, through a filter, typically a low-pass filter, in order to filter out interfering frequencies.

[0005] Suitable electronic filter units are known to those skilled in the art from the prior art and are commercially available from various users, both in the form of analog and digital filters. Corresponding electronic filter units are usually characterized by their so-called cutoff frequency, also referred to as the corner frequency. A low-pass filter, for example, is an electronic component that allows signals with frequencies below the corresponding cutoff frequency to pass largely unchanged, but reduces the intensity of signal components with frequencies above the cutoff frequency. In contrast, the corresponding functionality of a high-pass filter is inverted.In addition, so-called bandpass filters are used, in which an upper and a lower cutoff frequency together span a frequency band in which the corresponding signal components can pass largely unhindered, while they are attenuated above and below the frequency band. Such bandpass filters can be achieved, for example, by combining a high-pass filter with a low-pass filter.

[0006] In the field of sensor technology for vehicle tires, a particular problem is that the interference frequencies that occur depend on the mechanical loads that occur during driving.

[0007] These loads, and thus the most relevant interference frequencies, depend particularly on the size of the vehicle tire. Since the sensor units are regularly positioned on the inner layer of the pneumatic tire, facing away from the tread, the relevant frequency ranges of the most intense interference correlate accordingly with the position of the electronic sensor unit in the pneumatic tire.

[0008] In practice, this often means that sensor units intended for installation in pneumatic vehicle tires must be adapted in advance to the dimensions of the final tire product. The cutoff frequency of the electronic filter in the sensor unit is adjusted to the tire radius in order to filter out the relevant interference frequencies as much as possible without losing too much of the desired signal. Since the end user in tire production (or even the end customer) is generally not expected to adjust the cutoff frequency to the respective tire size, this means that during production of corresponding sensor units, factory-specified cutoff frequencies are usually set, which predestine the sensor units for use in your specific tire type or with a specific tire size.

[0009] This situation is often seen as a disadvantage in the technical field. Since tire manufacturers regularly produce a large number of different sized tire types, this means that a large number of differently pre-set sensor units have to be handled and stored in component logistics, which results in increased effort and more space requirements. In addition, the use of specifically pre-set components always carries the risk that the specific sensor units required for a certain production batch are not available, while any existing sensor units cannot be adjusted to the needs of the production batch or only with great effort. There is also the risk that incorrectly adjusted electronic sensor units, i.e. electronic sensor units with a cut-off frequency that does not match the tire type, are installed in vehicle tires.However, in many cases it is difficult to detect such a manufacturing defect at the factory and, moreover, it is usually very difficult to correct it subsequently.

[0010] In addition, the inventors have found that even with sensor units that are sufficiently matched to the tire radius with regard to their cutoff frequency, interference frequencies can occur in the signal of the acceleration sensor during driving, especially at high speeds, despite this actually good matching, which negatively influences the signal quality.

[0011] The primary object of the present invention was to eliminate or at least reduce the disadvantages of the prior art.

[0012] In particular, it was the object of the present invention to provide a method for adjusting sensor units installed in pneumatic vehicle tires, with which the filter setting can be adapted in an efficient and automated manner to the respective properties of a vehicle tire equipped therewith and / or to the specific operating conditions of these vehicle tires.

[0013] It was a further object of the present invention that the method to be specified should result in optimally adjusted sensor-equipped pneumatic vehicle tires in an efficient manner, with which particularly advantageous signal qualities of the sensors installed in the sensor unit should be achievable as a result of an optimally adjusted cut-off frequency of the electronic filter unit, in particular also at different vehicle speeds.

[0014] In this respect, it was a particular object of the present invention that the method to be specified should eliminate the need for specifically preset sensor units in tire production and instead enable the installation of electronic sensor units of the same type in different vehicle tires of various sizes, which, thanks to their suitability for carrying out the method to be specified, can be automatically adjusted to the specific tire type. In this case, it should be desirable to reduce the need for different electronic components and the associated storage and logistics costs in the production of vehicle tires equipped with electronic sensor units.

[0015] Moreover, it was a further object of the present invention to provide a corresponding sensor-equipped pneumatic vehicle tire which is particularly suitable for carrying out the method according to the invention and which can provide sensor data with an excellent signal quality, in particular under various application conditions.

[0016] The inventors of the present invention have now found that the objects described above can be achieved if, in a method for adjusting an electronic sensor unit in a pneumatic vehicle tire, a pneumatic vehicle tire equipped with a sensor unit is provided, the sensor unit of which comprises an acceleration sensor and an electronic filter unit, if, during the rotation of the pneumatic vehicle tire, radius information about the positioning of the sensor unit in the pneumatic vehicle tire and / or speed information about the rotational speed of the pneumatic vehicle tire is determined and the cutoff frequency of the electronic filter unit is changed as a function of this determined radius information and / or as a function of this determined speed information using an electronic data processing device, as defined in the claims.

[0017] The above-mentioned objects are thus achieved by the subject matter of the invention as defined in the claims. Preferred embodiments of the invention emerge from the subclaims and the following statements.

[0018] Such embodiments, which are designated as preferred below, are combined in particularly preferred embodiments with features of other embodiments designated as preferred. Combinations of two or more of the embodiments designated as particularly preferred below are thus very particularly preferred. Likewise preferred are embodiments in which a feature of an embodiment designated as preferred to any extent is combined with one or more further features of other embodiments designated as preferred to any extent. Features of preferred pneumatic vehicle tires result from the features of preferred methods.

[0019] The invention particularly relates to a method for adjusting an electronic sensor unit in a pneumatic vehicle tire with an electronic data processing device, wherein the pneumatic vehicle tire comprises a tread, a tire inner layer and an electronic sensor unit arranged below the tread on the tire inner layer, wherein the electronic sensor unit comprises: i) an acceleration sensor for detecting the time-dependent acceleration, and ii) an electronic filter unit, wherein the electronic filter unit has at least one cut-off frequency, wherein the pneumatic vehicle tire is arranged on a vehicle, preferably a commercial vehicle, wherein the method is carried out while the vehicle is in operation, comprising the method steps: a1) Determining radius information of the sensor unit during the rotation of the vehicle tire with an electronic data processing device, wherein the radius information is the distance of the sensor unit from the rotation axis of the vehicle pneumatic tire in the radial direction or correlates with this distance, and b1) Changing the cutoff frequency of the electronic filter unit depending on the radius information with the electronic data processing device, and additionally or alternatively the method steps: a2) determining speed information during the rotation of the vehicle tire with an electronic data processing device, wherein the speed information is the rotational speed of the vehicle tire or correlates with the rotational speed of the vehicle tire, and b2) Changing the cutoff frequency of the electronic filter unit as a function of the speed information using the electronic data processing device.

[0020] The method according to the invention serves to adjust an electronic sensor unit in a pneumatic vehicle tire arranged on the vehicle and is accordingly intended in particular for use during driving.

[0021] This adjustment is not performed manually, but rather with an electronic data processing device. In accordance with the expert's understanding, this means that in the method according to the invention, the electronic sensor unit, in particular its electronic filter unit, is controlled or adjusted via the electronic data processing device depending on information determined in method steps a1) and / or a2).

[0022] The functionality required by the electronic data processing device or electronic sensor unit can be implemented using suitable software. Commercially available electronic sensor units equipped with an electronic filter unit typically include a suitable interface and a basic functionality for changing the cutoff frequency. The inventors believe that the implementation of the corresponding functionality will be possible for a person skilled in the art, even with relatively basic programming knowledge, given the invention.

[0023] The method according to the invention uses a sensor-equipped pneumatic vehicle tire, which, in terms of its basic structure, corresponds to the pneumatic vehicle tires known from the prior art. The pneumatic vehicle tire comprises a tread and is lined with an inner tire layer. The electronic sensor unit is located below the tread and is arranged directly or indirectly on the inner tire layer. An example of a method according to the invention is one in which the electronic sensor unit is arranged centrally below the tread on the inner tire layer.

[0024] The electronic sensor unit to be used in the method according to the invention comprises at least one acceleration sensor, which serves to detect the time-dependent acceleration during the rotation of the vehicle tire. Furthermore, the electronic sensor unit also comprises an electronic filter unit, which has at least one cutoff frequency. The electronic sensor unit thus comprises several components, which can, for example, be structurally integrated into a single component or, alternatively, can be implemented as separate components connected to one another in a signal-conducting manner.

[0025] The electronic sensor unit initially comprises an acceleration sensor capable of determining the time-dependent acceleration a(t) in at least one direction, preferably the radial direction. A method according to the invention is preferred, wherein the acceleration sensor is a 3-axial acceleration sensor.

[0026] The acceleration sensor in the electronic sensor unit provides data that can be used, for example, in an indirect method for estimating the tread depth of a vehicle tire. In many cases, the acceleration sensor will constitute the primary sensor functionality of the sensor unit; however, it is also conceivable that the electronic sensor unit may also contain additional sensors, such as pressure and / or temperature sensors, which could also benefit from the method according to the invention with regard to the quality of the provided signal.

[0027] In addition to the acceleration sensor, the electronic sensor unit comprises at least one electronic filter unit. According to the invention, this electronic filter unit has at least one cutoff frequency, which characterizes the extent to which the electronic filter unit allows or attenuates signals of different frequencies.

[0028] Of particular relevance for the method according to the invention are low-pass filters and band-pass filters, in which the cutoff frequency, or the upper of two cutoff frequencies, indicates the frequency above which attenuation of the signals is achieved. The person skilled in the art will understand that in the method according to the invention, in the case of a low-pass filter, usually the only cutoff frequency is changed, whereas in the case of a band-pass filter, one or both cutoff frequencies of the frequency band, preferably at least the upper cutoff frequency of the frequency band, are changed. A method according to the invention is preferred, wherein the electronic filter unit is configured to (i) electronic signals with a frequency above the cut-off frequency and electronic signals with a frequency below the cut-off frequency, or ii) to attenuate electronic signals with a frequency within the frequency band defined by the cutoff frequencies and outside the frequency band to different degrees, wherein the electronic filter unit is preferably configured to attenuate electronic signals with a frequency above the cutoff frequency more strongly than electronic signals with a frequency below the cutoff frequency or within the frequency band. In other words, a method according to the invention is preferred, wherein the electronic filter unit is a low-pass filter or a band-pass filter, preferably a low-pass filter, wherein the cutoff frequency changed in method step b1) or b2) is preferably the upper cutoff frequency of the frequency band of the band-pass filter in the case of a band-pass filter.

[0029] Those skilled in the art will understand that the acceleration sensor and the electronic filter unit interact in such a way that the time-dependent acceleration signal output by the acceleration sensor is filtered by the electronic filter unit. In other words, this is a method according to the invention, wherein the electronic sensor unit is configured to filter the signal output by the acceleration sensor through the electronic filter unit.

[0030] In principle, analog filters can also be used to implement the electronic filter unit, which can be constructed using electronic components such as resistors, capacitors, or tracks. Alternatively, and preferably, the electronic filter unit can be formed by an electronic data processing device that applies the desired filter via a digital filter. In this case, the electronic data processing device can be the electronic data processing apparatus that also performs the cutoff frequency adjustment in the method according to the invention. Thus, a method according to the invention is conceivable in which the electronic filter unit comprises one or more analog filters.However, a method according to the invention is particularly preferred, wherein the electronic filter unit comprises an electronic data processing device which is designed to filter the signal output by the acceleration sensor with a digital filter.

[0031] Even if it would be at least theoretically conceivable to apply a similarly designed method during tire production, for example to optimally adjust the electronic sensor units to the respective tire radius at the factory, it is nevertheless to be seen as a particularly great advantage of the method according to the invention that it can be carried out particularly efficiently even after the sensor-equipped vehicle tires have been attached to a vehicle and in particular during driving, which also enables continued optimization of the cut-off frequency during driving and in particular optimized adaptation to the respective driving speed.

[0032] In addition to the components described above, the electronic sensor unit optionally comprises further components. In particular, in almost all cases, the electronic sensor unit will comprise means via which the electronic sensor unit can communicate with a communication unit arranged outside the vehicle's pneumatic tire using a wireless communication method, so that, in particular, reading of the electronic sensor unit is possible during driving. Accordingly, a method according to the invention is relevant for essentially all embodiments, wherein the electronic sensor unit additionally comprises: iv) an electronic transmitting unit for transmitting signals in a wireless data transmission method, preferably a transmitting and receiving unit for transmitting and receiving signals in a wireless data transmission method.

[0033] At least theoretically, it would be conceivable to arrange the electronic data processing device required for carrying out the method according to the invention outside the pneumatic vehicle tire, in particular inside the vehicle, and to effect the change in the cutoff frequency in the electronic filter unit by means of wireless communication. In this case, a method according to the invention would be one in which the electronic data processing device is arranged outside the pneumatic vehicle tire, preferably inside the vehicle, and comprises an electronic communication unit for communicating with the electronic sensor unit using a wireless data transmission method.

[0034] However, the inventors consider it particularly advantageous if the electronic data processing device is implemented as a component of the electronic sensor unit, since this results in an electronic sensor unit whose use in a pneumatic vehicle tire can produce an advantageous pneumatic vehicle tire, which is particularly preferred for use in the method according to the invention and which enables automatic adjustment of the optimal cutoff frequency of the electronic filter unit even without the need for external data processing devices, thus enabling a particularly autonomous process. For essentially all embodiments, a method according to the invention is therefore preferred, wherein the electronic sensor unit additionally comprises: (iii) an electronic data processing device.

[0035] The person skilled in the art will understand that in this case the electronic data processing device preferably has the corresponding functionality to also effect the change in the cut-off frequency.In other words, this is a method according to the invention, wherein the electronic data processing device is configured to determine the radius information of the sensor unit from the time-dependent acceleration detected by the acceleration sensor when the vehicle pneumatic tire rotates during driving operation, and to change the cutoff frequency of the electronic filter depending on the radius information, and / or wherein the electronic data processing device is configured to determine the speed information from the time-dependent acceleration detected by the acceleration sensor when the vehicle pneumatic tire rotates during driving operation, and to change the cutoff frequency of the electronic filter depending on the speed information.

[0036] The method according to the invention comprises steps a1) and b1) and / or method steps a2) and b2), depending on whether the electronic sensor unit is to be adjusted solely with regard to its position in the vehicle tire or the general dimensioning of the vehicle tire (a1 / b1) or whether, in addition or alternatively, the cutoff frequency is to be adjusted to the speed of the vehicle during driving operation. The inventors believe it is particularly advantageous to provide both adjustment options. Therefore, a method according to the invention is preferred, wherein the method comprises method steps a1 and b1 as well as a2 and b2.

[0037] Method steps a1) and b1) correspond to the adaptation of the cutoff frequency to the position of the sensor unit in the pneumatic vehicle tire or to the dimensions of the pneumatic vehicle tire. To implement this functionality, radius information assigned to the sensor unit is first determined. According to the invention, the determination takes place during the rotation of the vehicle tire and is performed by the electronic data processing device. In particularly simple embodiments, the radius information corresponds to the distance of the sensor unit from the axis of rotation of the pneumatic vehicle tire, measured along the radial direction. A particular advantage of this embodiment is that this value can usually be determined with relatively low computational effort, since the rotation radius of the sensor unit is the direct result of most determination methods.For certain process configurations, a method according to the invention is preferred, wherein the radius information is the distance of the sensor unit from the rotational axis of the pneumatic vehicle tire in the radial direction.

[0038] The distance of the sensor unit from the rotational axis of the pneumatic vehicle tire can be advantageously derived by a person skilled in the art, using fundamental mechanical principles, from the radial acceleration detected by the acceleration sensor. The following applies: r=a / ω2

[0039] Where r is the distance of the sensor unit from the axis of rotation, a is the radial acceleration, which in the case of a tire mounted on the vehicle is preferably the radial acceleration measured outside and preferably as far away as possible from the ground contact area in order to obtain the most accurate value, in particular when the sensor unit is arranged in the side of the vehicle tire facing away from the road surface, and ω is the angular velocity of the rotation of the sensor unit about the axis of rotation and thus the angular velocity of the rotating vehicle tire.

[0040] The angular velocity itself is given by the expression: ω=2*π / T with the rotational speed 1 / T of the pneumatic vehicle tire. Accordingly, the radius information required in the method according to the invention can be obtained in the form of the direct distance of the sensor unit from the rotation axis if information about the angular velocity or the rotational speed of the pneumatic vehicle tire is available. An example of a method according to the invention is accordingly, wherein the radius information is determined from the radial acceleration detected by the acceleration sensor during the rotation of the vehicle tire and the angular velocity or a value correlating therewith, preferably the angular velocity or the rotational speed, preferably the angular velocity.

[0041] At least theoretically, it is conceivable to obtain the information required for the calculation regarding the angular velocity or a value correlating therewith, for example the rotational speed, from an external measurement carried out, for example, by the vehicle's other sensors. However, in the inventors' estimation, this will be less advantageous in most cases. Accordingly, a method according to the invention is less advantageous and more preferred for certain applications, wherein the vehicle comprises means configured to determine the angular velocity of the rotating vehicle tire or a value correlating therewith, and / or wherein the angular velocity or the value correlating therewith is determined via a tachometer, preferably a tachometer arranged on a vehicle.

[0042] To obtain particularly advantageous pneumatic vehicle tires according to the invention and to implement a particularly favorable process control in the method according to the invention, the inventors consider it preferable for essentially all embodiments of the invention if the sensor technology already present in the electronic sensor unit is used to determine the radius information, whereby the dependence on additional sensors in the vehicle can be advantageously further reduced and corresponding pneumatic vehicle tires are given the ability to adjust the cutoff frequency in the method according to the invention largely independently. In a synergistic manner, the time-dependent acceleration, which is already detected by the acceleration sensor, provides measurement data from which the rotational speed can be derived and which, in combination with the acceleration, can be used to access the radius r.This is due to the fact that, as the pneumatic vehicle tire rotates, the acceleration sensor passes through the tire contact patch once per revolution. This pass through the deformed tire contact patch leads to a characteristic change in the time-dependent acceleration, well known from the prior art, as disclosed, for example, in DE 102015216212 A1. The rotational speed and thus indirectly the angular velocity are determined from the time interval between two consecutive passes through the tire contact patch. The corresponding evaluation can be carried out particularly easily and reliably by considering the derivative of the time-dependent acceleration, in which a pass of the acceleration sensor through the tire contact patch results as a signal consisting of a low point and a high point, and is therefore particularly clearly identifiable.Based on this, the person skilled in the art can select a clear reference point in the signal recorded during the pass, for example the absolute minimum in a rotational interval or the absolute maximum, and determine the time interval between two reference points assigned to successive passes through the tire contact patch in order to calculate the rotational speed therefrom, for example. Accordingly, a method according to the invention is preferred, wherein the angular velocity or the value correlating therewith, in particular the rotational speed, is determined from the time-dependent acceleration, preferably from the distance between two adjacent extreme points in the time derivative of the radial acceleration detected by the acceleration sensor during the rotation of the vehicle tire, wherein the two adjacent extreme points correlate with different passes of the sensor unit through the region of the tire contact patch.

[0043] Although using the rotation radius of the sensor unit as radius information already yields good results, the inventors have discovered that the interference frequencies occurring during driving also depend in particular on the actual radius of the vehicle tire. Particularly for vehicle tires where a significant difference between the radius of the sensor unit and the actual radius of the tread surface occurs due to the high tire thickness, a cutoff frequency adjusted to the position of the sensor unit can potentially lead to poorer signal quality.Against this background, the inventors propose that, instead of the direct distance of the sensor unit from the rotation axis as the radius information decisive for the subsequent change in the cutoff frequency, a value can advantageously be used that correlates with the distance of the sensor unit but is obtained by applying a tire thickness correction term through a computational operation. Accordingly, a method according to the invention is preferred, wherein the radius information is a corrected radius value obtained by adding the distance of the sensor unit from the rotation axis of the pneumatic vehicle tire in the radial direction to a tire thickness correction term.

[0044] The inventors have thus succeeded in identifying advantageous magnitudes for corresponding tire thickness correction terms, whereby, in the inventors' estimation, a distinction between passenger car and truck tires is particularly expedient. Firstly, a method according to the invention is preferred, wherein the tire thickness correction term is a uniform tire thickness correction term in the range from 10 to 45 mm. Furthermore, a method according to the invention is particularly preferred, wherein the tire thickness correction term differs depending on the vehicle tire type, wherein the tire thickness correction term for passenger car tires is preferably in the range from 10 to 20 mm and for truck tires is preferably in the range from 30 to 45 mm.

[0045] As a particularly advantageous embodiment for the application of a tire thickness correction term, the inventors propose that the size of the tire thickness correction term can be determined depending on the previously determined distance of the sensor unit. This takes advantage of the fact that, based on the distance value of the sensor unit, it is usually possible to roughly estimate whether the tire is a passenger car tire or a commercial vehicle tire. This allows, for example, a larger correction term to be applied when a certain sensor unit defense level is exceeded, in order to account for the typically higher tire thicknesses of commercial vehicle tires.A method according to the invention is particularly preferred, wherein the tire thickness correction term is dependent on the distance of the sensor unit from the rotation axis of the pneumatic vehicle tire, wherein preferably below a predetermined distance value a first tire thickness correction term, preferably in the range of 10 to 20 mm, is used, and above a predetermined distance value a second tire thickness correction factor, preferably in the range of 30 to 45 mm, is used.

[0046] In method step b1) of the method according to the invention, the cutoff frequency of the electronic filter unit is changed, for example, shifted to higher or lower frequencies. The change occurs depending on the radius information, i.e., the distance of the sensor unit from the rotational axis of the vehicle's pneumatic tire or a value correlating therewith, for example, a distance value corrected by a tire thickness correction term.

[0047] In a comparatively simple implementation of the method according to the invention, the cutoff frequency can be changed linearly, for example, based on stored initial radius information. Due to the comparatively simple implementation, a method according to the invention is preferred, wherein the cutoff frequency in method step b1) is changed proportionally or inversely proportionally to the determined radius information.

[0048] Even though improved signal quality can be achieved with the comparatively simple cutoff frequency adjustment disclosed above, the inventors propose that particularly optimal results can be achieved for many applications with more complex, for example, non-linear adjustments. For example, predetermined cutoff frequency values ​​can be assigned to the radius information or ranges of radius information in tabular form, enabling particularly precise adjustment. Advantageously, the use of tabulated values ​​also allows for a method that requires particularly low computing capacity.A method according to the invention is preferred, wherein the cutoff frequency in method step b1) is changed as a function of the radius information to a predetermined cutoff frequency value assigned to the radius information, wherein the predetermined cutoff frequency values ​​are preferably assigned to the radius information via a table, wherein particularly preferably a predetermined cutoff frequency value is assigned to each parameter range of radius information.

[0049] Both a (possibly inversely) proportional adjustment and a configuration with tabulated values ​​can be obtained by a person skilled in the art for the tire sizes and / or tire types relevant to them, both experimentally in basic measurement series and calculated using computer-based simulation methods. In the inventors' opinion, due to the numerous influencing factors during driving and the corresponding complexity of the simulation, experimental determination and storage of suitable cutoff frequency values ​​for different radius information is particularly advantageous. Accordingly, a method according to the invention is preferred, wherein the assignment of the cutoff frequency values ​​to the radius information is determined experimentally or simulated by means of a computer simulation, preferably determined experimentally.

[0050] In particular, if the cutoff frequency has already been adjusted depending on the tire dimensions in a method according to the invention, the method according to the invention can be used synergistically to account for the changed interference frequencies at different speeds of rotation of the vehicle tire and thus the vehicle speed by changing the cutoff frequency of the electronic filter unit. Speed ​​information is determined in this process.

[0051] In the simplest cases, the speed information is directly the rotational speed of the vehicle tire, wherein, in accordance with expert understanding, parameters can again be used which correlate with the rotational speed of the vehicle tire, for example the rotational speed, which in preferred embodiments as described above can be obtained from the time-dependent acceleration data of the acceleration sensor. Alternatively, at least theoretically, the vehicle speed can also be used as speed information, since this also correlates with the rotational speed of the pneumatic vehicle tire. However, analogous to the radius information, it is particularly preferred with regard to the speed information if this is determined by means of the sensor technology of the sensor unit, i.e. without the need to input external parameters such as the vehicle speed.A method according to the invention is preferred, wherein the speed information is selected from the group consisting of the rotational speed of the pneumatic vehicle tire, the rotational speed of the pneumatic vehicle tire and the vehicle speed, preferably the rotational speed of the pneumatic vehicle tire and the rotational speed of the vehicle tire, particularly preferably the rotational speed of the pneumatic vehicle tire.

[0052] Although, in the inventors' estimation, tabulated values ​​can also be used in the case of speed-based adaptation, the inventors believe that it is particularly preferable for this method step to use an adaptation that scales (inversely) proportionally with the speed information. A method according to the invention is preferred, wherein the cutoff frequency in method step c2) is changed proportionally or inversely proportionally to the determined speed information.

[0053] If both the speed-based adjustment and the radius-based adjustment are to be performed in the method according to the invention, the inventors have found that this can advantageously be performed essentially additively, thereby significantly minimizing the required computational effort. This can be achieved particularly easily if one of the adjustments, preferably the speed-based adjustment, is modified via an adjustment function, preferably by means of a proportional or inversely proportional change.

[0054] Analogous to the change depending on the radius information, a method according to the invention is also preferably used for the speed-based adaptation, wherein the extent of the change depending on the speed information is determined experimentally or simulated by means of a computer simulation, preferably determined experimentally.

[0055] The method according to the invention can advantageously be carried out for several or all vehicle tires of a vehicle. Accordingly, a method according to the invention is preferred, wherein the method is carried out sequentially or simultaneously, preferably simultaneously, for a plurality of pneumatic vehicle tires arranged on the vehicle.

[0056] At least in principle, it is conceivable that the radius-based adjustment of the cutoff frequency is carried out only once and that the cutoff frequency thus determined, subject to any speed-based adjustment, is then maintained over the entire operating period. However, the inventors consider it particularly advantageous to exploit the ability for automatic adjustment to readjust the cutoff frequency at specific intervals or as a result of previously determined events. An example of a method according to the invention is one in which method steps a1) and b1) are repeated after a recalibration condition occurs, wherein the recalibration condition is selected from the group consisting of a completed tire change of the pneumatic vehicle tire on a vehicle, the adjustment of the tire pressure in the pneumatic vehicle tire, and a manual input on the electronic data processing device.

[0057] With regard to the implementation rate of the speed-based change, the inventors propose that, in an advantageous embodiment, this can be performed virtually "on demand," so that the optimal setting of the cutoff frequency is adapted to the specific speed information as soon as possible before the filter is applied. In this case, this is a method according to the invention, wherein method steps a2) and b2) are performed immediately before the sensor unit performs a measurement or calculation in which the electronic filter unit is used to filter a signal.

[0058] Additionally or alternatively, it is also conceivable that the method according to the invention is carried out at a predetermined rate with regard to the speed adjustment. A method according to the invention is preferred, wherein method steps a2) and b2) are carried out during the rotation of the tire at a rate in the range of 1 / 150 to 2 1 / s, preferably in the range of 1 / 50 to 1 / 2 1 / s, particularly preferably in the range of 1 / 20 to 1 / 10 1 / s.

[0059] The invention also relates to a pneumatic vehicle tire for use in a method according to the invention, having a tread and a tire inner layer, comprising an electronic sensor unit arranged below the tread on the tire inner layer, comprising: i) an acceleration sensor for detecting the time-dependent acceleration, ii) an electronic filter unit, wherein the electronic filter unit has a cut-off frequency and is designed to attenuate electronic signals with a frequency above the cut-off frequency and electronic signals with a frequency below the cut-off frequency to different degrees, and iii) an electronic data processing device, wherein the electronic data processing device is configured to determine the radius information of the sensor unit from the time-dependent acceleration detected by the acceleration sensor when the vehicle pneumatic tire rotates during driving operation, and to change the cut-off frequency of the electronic filter unit depending on the radius information, and additionally or alternatively is configured to determine the speed information from the time-dependent acceleration detected by the acceleration sensor when the vehicle pneumatic tire rotates during driving operation, and to change the cut-off frequency of the electronic filter unit depending on the speed information.

[0060] The invention and preferred embodiments of the invention are explained and described in more detail below with reference to the accompanying figures. Fig. 1 a schematic cross-sectional view through a pneumatic vehicle tire according to the invention with a sensor unit arranged on the tire inner layer in a preferred embodiment; and Fig. 2 an exemplary representation of the time-dependent radial acceleration over time for two consecutive passes of an acceleration sensor through the tire contact patch of a vehicle tire; and Fig. 3 an exemplary representation of the first derivative of the time-dependent radial acceleration with respect to time for the passage of an acceleration sensor through the tire contact patch of a pneumatic vehicle tire.

[0061] Fig. 1 shows a schematic cross-sectional view of a pneumatic vehicle tire 12, on the tire inner layer 14 of which an acceleration sensor 10 is arranged, which is positioned centrally below the tread.

[0062] The electronic sensor unit 10 comprises an acceleration sensor, which is preferably designed as a triaxial acceleration sensor. Furthermore, the electronic sensor unit 10 comprises an electronic data processing device configured to carry out method steps a1) and b1) as well as method steps a2) and b2) of the method according to the invention, so that the electronic sensor unit 10 used in the vehicle tire 12 according to the invention is specifically configured to be able to carry out the method according to the invention.

[0063] In the example shown the Fig. 1, the electronic sensor unit 10 comprises a digital low-pass filter, the cutoff frequency of which can be changed by the electronic data processing device as a function of radius information or speed information, and thus forms the electronic filter unit.

[0064] After the pneumatic vehicle tire 12 according to the invention has been arranged on a vehicle, the method according to the invention can be carried out while the vehicle is in operation. The electronic sensor unit 10 of the Fig. 1 is designed to determine the angular velocity as speed information from the time-dependent acceleration data, in particular the first derivative of the time-dependent acceleration with respect to time, or to derive the radius information from the angular velocity and the determined acceleration. For this purpose, the electronic data processing device determines an acceleration value in a range which is Fig. 2 is designated as D, in which the sensor unit 10 is located away from the ground contact surface. An exemplary point is shown in Fig. 2 also as t DIn addition, the electronic data processing device determines the angular velocity via the time interval between two consecutive minima B. Preferably, the electronic data processing device determines the time interval between two passes of the electronic sensor unit 10 through the tire contact area as the distance between two consecutive high points or alternatively between two consecutive low points in the time course of the first derivative, which in Fig. 3 are shown by a dashed line on the y-axis.

[0065] In the example shown the Fig. 1, the electronic data processing device is configured to use not the calculated distance of the sensor unit from the rotational axis of the pneumatic vehicle tire 12 itself as radius information, but to use a corrected radius value of the vehicle tire 12 as radius information by adding a tire thickness correction term and to use this value as the basis for the subsequent adjustment of the cut-off frequency. In the preferred embodiment shown, the Fig. 1, the electronic data processing device is configured to estimate, via the absolute radius value of the sensor unit 10, whether the sensor unit 10 is installed in a passenger car or a truck tire, and to apply a predetermined tire thickness correction term on a case-by-case basis, which in the case of pneumatic truck tires is, for example, a factor of 2 larger.

[0066] In the example shown, the memory unit of the electronic data processing device assigns corresponding cutoff frequencies to specific parameter ranges of the radius information in tabular form, which were previously identified experimentally as optimal cutoff frequencies. In the method according to the invention, the electronic data processing device compares the determined radius information with the tabulated values ​​and changes the cutoff frequency of the low-pass filter accordingly.

[0067] In addition to the radius-based adjustment of the cut-off frequency, the electronic data processing device of the pneumatic vehicle tire 12 according to the invention is Fig.1 is also designed to provide an additional change in the cutoff frequency depending on the determined speed information, namely immediately before the electronic sensor unit 10 performs an operation which requires the filtering of a signal. List of reference symbols 10 Accelerometer 12 pneumatic vehicle tires 14 Tire inner layer QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 102015216212 A1 [0003, 0042] WO 2021192474 A1

[0003] US 9669664 B2

[0003] CN 107727042 A

[0003] US 20210208029 A1

[0003] US 20200056983 A1

[0003]

Claims

[1] Method for adjusting an electronic sensor unit (10) in a pneumatic vehicle tire (12) with an electronic data processing device, wherein the pneumatic vehicle tire (12) comprises a tread, a tire inner layer (14) and an electronic sensor unit (10) arranged below the tread on the tire inner layer (14), wherein the electronic sensor unit (10) comprises: i) an acceleration sensor for detecting the time-dependent acceleration, and ii) an electronic filter unit, wherein the electronic filter unit has at least one cut-off frequency, wherein the pneumatic vehicle tire (12) is arranged on a vehicle, wherein the method is carried out while the vehicle is in operation, comprising the method steps: a1) determining radius information of the sensor unit (10) during the rotation of the vehicle tire (12) with an electronic data processing device, wherein the radius information is the distance of the sensor unit (10) from the rotation axis of the vehicle pneumatic tire (12) in the radial direction or correlates with this distance, and b1) Changing the cut-off frequency of the electronic filter unit depending on the radius information using the electronic data processing device, and additionally or alternatively the method steps: a2) determining speed information during the rotation of the pneumatic vehicle tire (12) with an electronic data processing device, wherein the speed information is the rotational speed of the pneumatic vehicle tire or correlates with the rotational speed of the pneumatic vehicle tire, and b2) Changing the cutoff frequency of the electronic filter unit depending on the speed information using the electronic data processing device. [2] Method according to claim 1, wherein the method comprises the method steps a1) and b1) and a2) and b2). [3] Method according to one of claims 1 or 2, wherein the radius information is determined from the radial acceleration detected by the acceleration sensor during the rotation of the pneumatic vehicle tire (12) and the angular velocity or a value correlating therewith. [4] Method according to claim 3, wherein the angular velocity or the value correlating therewith is determined from the distance between two adjacent extreme points in the time derivative of the radial acceleration detected by the acceleration sensor during the rotation of the pneumatic vehicle tire (12), wherein the two adjacent extreme points correlate with different passes of the sensor unit through the region of the tire contact area. [5] Method according to one of claims 1 to 4, wherein the electronic filter unit is a low-pass filter or a band-pass filter. [6] Method according to one of claims 1 to 5, wherein the electronic sensor unit (10) additionally comprises: (iii) an electronic data processing device. wherein the electronic data processing device is configured to determine the radius information of the sensor unit (10) from the time-dependent acceleration detected by the acceleration sensor when the pneumatic vehicle tire (12) rotates during driving operation on a vehicle, and to change the cut-off frequency of the electronic filter depending on the radius information, and / or wherein the electronic data processing device is configured to determine the speed information from the time-dependent acceleration detected by the acceleration sensor when the vehicle pneumatic tire (12) rotates during driving operation, and to change the cut-off frequency of the electronic filter unit as a function of the speed information. [7] Method according to one of claims 1 to 6, wherein the radius information is a corrected radius value obtained by adding the distance of the sensor unit (10) from the rotation axis of the pneumatic vehicle tire in the radial direction to a tire thickness correction term. [8] Method according to one of claims 1 to 7, wherein the cut-off frequency in method step b1) is changed as a function of the radius information to a predetermined cut-off frequency value associated with the radius information. [9] Method according to one of claims 1 to 8, wherein the cut-off frequency in method step b2) is changed proportionally or inversely proportionally to the determined speed information. [10] Pneumatic vehicle tyre (12) for use in a method according to one of claims 1 to 9, having a tread and a tyre inner layer (14), comprising an electronic sensor unit (10) arranged below the tread on the tyre inner layer (14), comprising: i) an acceleration sensor for detecting the time-dependent acceleration, ii) an electronic filter unit, wherein the electronic filter unit has a cut-off frequency and is designed to attenuate electronic signals with a frequency above the cut-off frequency and electronic signals with a frequency below the cut-off frequency to different degrees, and (iii) an electronic data processing device, wherein the electronic data processing device is configured to determine the radius information of the sensor unit (10) from the time-dependent acceleration detected by the acceleration sensor when the vehicle pneumatic tire (12) rotates during driving operation, and to change the cut-off frequency of the electronic filter unit depending on the radius information, and is additionally or alternatively configured to determine the speed information from the time-dependent acceleration detected by the acceleration sensor when the vehicle pneumatic tire rotates during driving operation, and to change the cut-off frequency of the electronic filter unit depending on the speed information.

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