Method for analyzing the material composition of a vehicle tire and device for analyzing the material composition of a vehicle tire

Abstract

A method for analyzing the material composition of a vehicle tire comprises the following steps: Providing a sample (200) representing a section or the entire vehicle tire. Emitting laser radiation from a laser (300) with a first predetermined wavelength (W1) to excite a first section (201) of the sample (200). Receiving fluorescence radiation from the first section (201) of the sample (200). Measuring the received fluorescence radiation using a sensor device (400). Quantifying and converting the measured fluorescence radiation into digital data. Storing the digital data in a database (500). Classifying the digital data based on the fluorescence radiation and determining the material composition based on the classification.

Description

[0001] The present disclosure relates to a method for analyzing the material composition of a vehicle tire. The present disclosure further relates to a device for analyzing the material composition of a vehicle tire.

[0002] The demand for recyclable products is steadily increasing, including in the automotive sector and especially in the area of ​​vehicle tires. A vehicle tire, also known as a motor vehicle tire, pneumatic tire, or simply tire, has a tread and a bead. The areas of different material compositions within tire sections are typically determined manually by an expert. A standard flatbed scanner is used for documentation purposes. It is conventionally difficult to distinguish material compositions, also called tire rubber compounds, using measurement techniques, especially optically or non-contact methods.

[0003] It is desirable to provide a method for analyzing the material composition of a vehicle tire or a section thereof, enabling the material composition to be distinguished metrologically in a simple and reliable manner. Furthermore, it is desirable to provide a method and a device for analyzing the material composition of a vehicle tire or a section thereof, enabling the material composition to be distinguished optically or non-contact.

[0004] Embodiments of the present disclosure relate to a method for analyzing the material composition of a vehicle tire or a part thereof. Further embodiments of the disclosure relate to a device for analyzing the material composition of a vehicle tire or a part thereof.

[0005] The advantages, features and designs of the method also apply to the device and vice versa.

[0006] The procedure for analyzing the material composition of a vehicle tire comprises the following steps. First, a sample is prepared. The sample may represent a section of the vehicle tire or the entire tire. The procedure for analyzing the material composition of a vehicle tire is not limited to an entire tire. For example, only a section of the tire may be analyzed. For instance, a tire may be cut open so that the cross-section with its different sections is visible. This cross-section could then be the sample. Alternatively, an outer surface of the tire may be used as the sample. Another alternative is to cut out a defined area from the tire or granulate a section of the tire to be used as the sample.

[0007] In this context, the vehicle tire is either a vulcanized tire or an unvulcanized tire.

[0008] The analysis of vehicle tires also includes the analysis of tire components. A tire component, for example, represents a section of the vehicle tire. A tire component is, for instance, a tread strip. A co-extruded tread strip, for example, contains three materials or compounds in the extrudate. The co-extruded tread strip cannot be fed into the mixer for reuse or further processing because the compound in the mixer would only be one of the three compounds in the co-extrudate and would therefore contaminate the co-extrudate. Accordingly, the composition of the tire component is determined. Specifically, it is determined which compound is used in which area of ​​the tire component. This makes it possible to separate the different compounds and feed them into the appropriate mixer.

[0009] The process further includes the step of emitting laser radiation with a first, predetermined wavelength. This laser radiation excites the first section of the sample. For example, the sample is excited using a line laser. The line laser excites the sample, for instance, with a wavelength in the range of 500 nm to 1000 nm. This excitation causes the emission of fluorescence. In a further step, the fluorescence is received by the excited first section of the sample. The received fluorescence is measured using a sensor device. The wavelength used is not limited to a single wavelength. The laser can, for example, excite the sample with two or more different wavelengths.

[0010] Fluorescence spectroscopy measures the fluorescence emitted by a sample after prior excitation. For this purpose, the sample is illuminated with monochromatic radiation, and the redshifted emitted radiation is detected. The spectral profile of the fluorescence is independent of the wavelength of the excitation radiation. The intensity of the fluorescence correlates with the absorption of the molecule. It is also possible to perform so-called excitation-emission measurements. For this, the excitation wavelength is varied stepwise, and an emission spectrum is determined for each wavelength step.

[0011] The measured fluorescence radiation is quantified and converted into digital data. This digital data is stored in a database. The digital data is then stitched together into a single data file to ensure immediate comparability.

[0012] In this way, the local distribution of the compounds within the test specimen is measured. This generates an image coordinate system of the compound distribution, in which the data is assigned a coordinate corresponding to the spectrum of the measured fluorescence radiation. Alternatively, each coordinate is assigned one of the data points. The vehicle tire or the relevant section of the tire is mapped. This creates a kind of map on which the analyzed areas of the vehicle tire or the relevant section are assigned to one or more compounds.

[0013] The digital data is classified based on the fluorescence radiation. This classification determines the material composition of the measured section. The classified data is then compared with predefined material compositions. For example, the classification might reveal different material compositions in the tire sections, which are characteristic of the measured fluorescence radiation. The classification might also identify vulcanized and unvulcanized tire rubber compounds with the same material composition.

[0014] The fluorescence of some tire rubber compounds is caused by the plastic molecules themselves. Additionally, fluorescence is caused by additives, impurities (such as those resulting from polymerization processes), or degradation products of the plastic molecules. Based on this knowledge, the fluorescence spectrum can be used to determine a class that represents the material composition.

[0015] An alternative or additional way to use fluorescence spectroscopy for classifying tire compositions or rubber compounds is to add small amounts of appropriate fluorescent markers during the production of a vehicle tire. This allows for simple subsequent sorting using fluorescence spectrometers.

[0016] This method allows for the simple and reliable measurement of different material compositions within a vehicle tire. Furthermore, it identifies the precise location within the tire, or within a specific section of the tire, where each material composition or compound is present.

[0017] According to one embodiment, the method includes the process step of emitting laser radiation with a second predetermined wavelength.

[0018] The laser radiation excites the first section of the sample. For example, the sample is excited using a line laser. The line laser excites the sample, for example, with a wavelength in the range of 500 nm to 1000 nm. This excitation causes the emission of fluorescence radiation. In a further step, the fluorescence radiation is received by the excited first section of the sample. The received fluorescence radiation is measured by the sensor device.

[0019] The measured fluorescence signal is quantified and converted into digital data. This digital data is stored in the database. The digital data is then stitched together into a single data file to ensure immediate comparability.

[0020] The digital data is classified based on the fluorescence radiation. This classification determines the material composition of the measured section. The classified data is then compared with predefined material compositions. For example, the classification might reveal different material compositions in the tire sections, which are characteristic of the measured fluorescence radiation. The classification might also identify vulcanized and unvulcanized tire rubber compounds with the same material composition.

[0021] The measurement of the received fluorescence radiation, which is emitted by the excitation of the sample body with the second wavelength, can take place before or after the measurement of the received fluorescence radiation, which is emitted by the excitation of the sample body with the first wavelength.

[0022] The use of the second wavelength allows for a better differentiation of the material composition based on the fluorescence radiation. The wavelength used is not limited to just two. The laser radiation excites the sample, for example, with a variety of different wavelengths. In this way, a complete fluorescence spectrum is generated across the wavelengths used, thus enabling a more comprehensive analysis of the material composition.

[0023] According to one embodiment, the method includes the step of changing the laser wavelength so that a predetermined wavelength range is traversed. This predetermined wavelength range extends, for example, from the first wavelength to the second wavelength. The laser radiation is emitted with at least two wavelengths from the predetermined wavelength range. The laser radiation excites the first section of the sample. This excitation causes the emission of fluorescence. For each wavelength used, the received fluorescence radiation from the excited first section is measured by the sensor device. The laser radiation excites the sample with, for example, a multitude of different wavelengths. In this way, a complete fluorescence spectrum across the wavelengths used is generated, thus enabling a more comprehensive analysis of the material composition.

[0024] The measured fluorescence radiation at different wavelengths is quantified and converted into digital data. This digital data is stored in a database. The digital data is then stitched together into a single data file to ensure direct comparability.

[0025] According to one embodiment, the method includes the step of emitting laser radiation with a first predetermined wavelength. The laser radiation excites the second section of the sample. For example, the sample is excited using a line laser. The line laser excites the sample, for example, with a wavelength in the range of 500 nm to 1000 nm. This excitation causes the emission of fluorescence radiation. In a further step, the fluorescence radiation is received by the excited first section of the sample. The received fluorescence radiation is measured by the sensor device. The wavelength used is not limited to a single wavelength. The laser radiation excites the sample, for example, with two or more different wavelengths.

[0026] The measured fluorescence radiation is quantified and converted into digital data. This digital data is stored in the database. The digital data is then stitched together into a single data file to ensure immediate comparability.

[0027] The digital data is classified based on the fluorescence radiation. This classification determines the material composition of the measured section. The classified data is then compared with predefined material compositions. For example, the classification might reveal different material compositions in the tire sections, which are characteristic of the measured fluorescence radiation. The classification might also identify vulcanized and unvulcanized tire rubber compounds with the same material composition.

[0028] According to one embodiment, the method includes the step of emitting laser radiation with at least two wavelengths from the specified wavelength range. The laser radiation excites the third section of the sample. This excitation causes the emission of fluorescence. For each wavelength used, the received fluorescence from the excited third section is measured by the sensor device. The laser radiation excites the sample, for example, with a multitude of different wavelengths. In this way, a complete fluorescence spectrum across the wavelengths used is generated, thus enabling a more comprehensive analysis of the material composition.

[0029] According to one embodiment, the method comprises the steps of comparing the classified material composition with reference data from the database. Based on the classified material composition, a section of the vehicle tire or the entire vehicle tire is marked with a label. The section of the vehicle tire or the entire vehicle tire is then sorted according to predefined criteria, depending on the label.

[0030] This method allows for better differentiation of tire rubber compounds. Areas with different compounds within tire sections can be identified. The process enables the differentiation of, for example, black tire rubbers and thus allows for automatic sorting based on material composition.

[0031] Based on previously conducted analyses, representatives are stored for different compounds. For example, representative spectra for each tire rubber compound are stored in the database.

[0032] The good distinguishability of the plastics offers a promising possibility for the sorting of black rubber materials or plastics.

[0033] According to one embodiment, the method includes the step of measuring the received fluorescence radiation using a hyperspectral sensor, so that a fluorescence spectrum is generated for each measured excited section.

[0034] Using, for example, a spectral line scan camera, the fluorescence spectrum is measured by the hyperspectral sensor and stored in a kind of multidimensional image in which each pixel contains a fluorescence spectrum.

[0035] Hyperspectral imaging (HSI), also known as imaging spectroscopy, extends known optical measurement methods by adding a spatial dimension. Instead of point measurements, HSI enables the simultaneous measurement of many spatially adjacent points on the sample. This allows for the rapid determination of lateral distributions of optically measurable properties of the sample.

[0036] In hyperspectral imaging, the electromagnetic radiation emitted by the sample under investigation is simultaneously detected with spectral and lateral resolution. A complete spectrum is obtained for every point on the sample. The wavelength range and the number of spectral channels can vary depending on the hyperspectral camera used.

[0037] The result of an HSI measurement is called a hypercube. This is an n-dimensional data object that contains the spatial extent in two dimensions and the spectral information of the image in the remaining dimensions.

[0038] The HSI is a powerful analytical tool that combines the advantages of spectroscopy with those of imaging. For each captured pixel, a spectrum with up to 1000 wavelengths in the relevant spectral range is stored. Using a hyperspectral sensor, it is possible to record the reflection or emission spectra of tire rubber compounds on a conveyor belt or with a moving sensor. Subsequently, each tire rubber compound can be assigned to a corresponding material class based on the characteristic bands of its reflection or emission spectrum.

[0039] According to one embodiment, the sample is moved relative to the laser and / or the sensor device. For example, the laser and / or the sensor device move over the sample. Alternatively or additionally, the sample moves under the laser and / or the sensor device.

[0040] According to one embodiment, the preparation of the sample body comprises the following steps: Cutting the sample body into a compact rubber body. Additionally or alternatively, the sample body is granulated into rubber granules. Cutting and granulating the sample body is performed with a cutting tool, for example, scissors. The compact rubber body is, for example, a single, continuous piece of the vehicle tire. The compact rubber body is, for example, a 10 cm x 10 cm sample body. Alternatively, the compact rubber body is a sample body with larger dimensions. Alternatively, the sample body is a tire grip or a section of the vehicle tire. A section of the vehicle tire is, for example, a halved vehicle tire where the cross-section is accessible to the laser radiation and for measurement.Alternatively, a section of the vehicle tire can be called a tire part. A tire part is, for example, a tread.

[0041] A device for analyzing the material composition of a vehicle tire is also provided. The device is configured to perform the steps of the method according to the embodiments. The device includes a sample holder for a test specimen. The device includes a laser for exciting the test specimen with laser radiation. For example, the test specimen is excited by means of a line laser. The line laser excites the test specimen, for example, with a wavelength in the range of 500 nm to 1000 nm. The excitation causes the emission of fluorescence radiation. The device further includes a sensor device. The sensor device is configured for measuring fluorescence radiation and recording a fluorescence spectrum of the test specimen. The sensor device includes, for example, a hyperspectral sensor.Using, for example, a spectral line scan camera, the fluorescence spectrum is measured by the hyperspectral sensor and stored in a type of multidimensional image in which each pixel contains a fluorescence spectrum. The device also includes a database for storing this multidimensional image of the recorded fluorescence spectrum. Each pixel of the multidimensional image contains a fluorescence spectrum. The database contains reference data with predefined material compositions of vehicle tires, each associated with a defined fluorescence spectrum.

[0042] Further advantages, features, and developments will become apparent from the following examples, which are explained in conjunction with the figures. Identical, similar, and equivalent elements can be marked with the same reference symbols across multiple figures. The figures and the relative sizes of the elements depicted within them are not to be considered to scale. Rather, individual elements may be exaggerated in size and / or thickness for better clarity and / or to improve representation.

[0043] They show: Fig. 1 Schematic side views of a device for analyzing the material composition of a vehicle tire according to an exemplary embodiment, Fig. 2 a flowchart of the procedure according to an exemplary embodiment.

[0044] Fig. Figure 1 shows a device 100 for analyzing the material composition of a vehicle tire. The device 100 has a sample holder 250 for a sample body 200. The device 100 has a laser 300 for exciting the sample body 200 with laser radiation. The laser radiation excites a first section 201 of the sample body 200. Alternatively or additionally, the laser radiation excites a second section 202 of the sample body 200. Alternatively or additionally, the laser radiation excites a third section 202 of the sample body 200. For example, the sample body 200 is excited by means of a line laser. The line laser excites the sample body 200, for example, with a wavelength in the range of 500 nm to 1000 nm. The wavelength used is not limited to a single wavelength. The laser 300 excites the sample body 200, for example, with two or more different wavelengths.The laser 300 excites the sample body 200, for example, in more than one section with two or more different wavelengths.

[0045] The sample body is, for example, a compact rubber body 210 or rubber granules 220. Cutting and granulating the sample body 200 is carried out using a cutting tool, such as scissors. The compact rubber body 210 is, for example, a single, continuous piece of the vehicle tire. The compact rubber body is, for example, a sample body 200 the size of a palm. Alternatively, the compact rubber body is a sample body 200 with a larger dimension. Alternatively, the sample body 200 is a tire grip or a section of the vehicle tire. A section of the vehicle tire is, for example, a halved vehicle tire where the cross-section is accessible to the laser radiation and for measurement.

[0046] The excitation causes the emission of fluorescence radiation. The device 100 further comprises a sensor device 400. The sensor device 400 is configured to measure fluorescence radiation and to record a fluorescence spectrum of the sample body 200. The sensor device 400 includes, for example, a hyperspectral sensor 410. Using, for example, a spectral line scan camera, the fluorescence spectrum is measured by the hyperspectral sensor 410 and stored in a type of multidimensional image in which each pixel contains a fluorescence spectrum. The device 100 further comprises a database 500 for storing a multidimensional image of the recorded fluorescence spectrum. Each pixel of the multidimensional image contains a fluorescence spectrum. The database 500 contains reference data with predefined material compositions of vehicle tires, which are assigned to a defined fluorescence spectrum.

[0047] Fig.Figure 2 shows a flowchart of the procedure for analyzing the material composition of a vehicle tire. In step S1, the sample 200 is prepared. The sample 200 represents a section of the vehicle tire or the entire tire. In step S2, laser radiation from laser 300 with the first predefined wavelength W1 is emitted. The laser radiation excites the first section 201 of the sample 200. In step S3, the fluorescence radiation from the excited first section 201 of the sample 200 is received. In step S4, the received fluorescence radiation is measured using the sensor device 400. In step S5, the measured fluorescence radiation is quantified and converted into digital data. In step S6, the digital data is stored in a database. In step S7, the digital data is classified based on the fluorescence radiation.In step S8, the material composition is determined based on the classification. The classified fluorescence radiation is compared, for example, with already classified tire rubber compounds from the database in order to draw conclusions about the composition and distribution of the compounds in the vehicle tire or in sections of the vehicle tire. Reference symbol list 100 Device 200 test specimens 201 first section 202 second section 203 third section 210 rubber bodies 220 rubber granules 250 sample holders 300 lasers 400 sensor device 410 Hyperspectral Sensor 500 database W1 first wavelength W2 second wavelength Delta_W wavelength range S1 - S8 \ Procedure steps

Claims

Method for analyzing the material composition of a vehicle tire, comprising: - Providing a sample (200) representing a section or the entire vehicle tire, - Emitting laser radiation from a laser (300) with a first predetermined wavelength (W1) to excite a first section (201) of the sample (200), - Receiving fluorescence radiation from the excited first section (201) of the sample (200), - Measuring the received fluorescence radiation using a sensor device (400), - Quantifying and converting the measured fluorescence radiation into digital data, - Storing the digital data in a database (500), - Classifying the digital data based on the fluorescence radiation, and - Determining the material composition based on the classification. The method according to claim 1, comprising: - Emitting laser radiation with a second predetermined wavelength (W2) to excite the first section (201) of the sample body (200); - Receiving the fluorescence radiation from the excited first section (201) of the sample body (200); - Measuring the received fluorescence radiation using the sensor device (400); - Quantifying and converting the measured fluorescence radiation into digital data; - Storing the digital data in the database (500); - Classifying the digital data based on the fluorescence radiation; and - Determining the material composition based on the classification. The method according to claim 2, comprising: changing the wavelength of the laser (300) so that a predetermined wavelength range (Delta_W) is traversed, which extends from the first wavelength (W1) to the second wavelength (W2), and emitting the laser radiation with at least two wavelengths from the predetermined wavelength range (Delta_W) to excite the first section (201) of the sample body (200), wherein for each wavelength the received fluorescence radiation from the excited first section (201) is measured by means of the sensor device (400), so that a fluorescence spectrum is generated. A method according to one of the preceding claims, comprising: - emitting laser radiation with the second predetermined wavelength (W2) to excite a second section (202) of the sample body (200), - receiving fluorescence radiation from the excited second section (202) of the sample body (200), - measuring the received fluorescence radiation using the sensor device (400), - quantifying and converting the measured fluorescence radiation into digital data, - storing the digital data in the database (500), - classifying the digital data based on the fluorescence radiation, and - determining the material composition based on the classification. Method according to claim 3, comprising emitting laser radiation with at least two wavelengths from the predetermined wavelength range (Delta_W) to excite a third section (203) of the sample body (200), wherein for each wavelength the received fluorescence radiation from the excited third section (203) is measured by means of the sensor device (400), so that a fluorescence spectrum is generated. Method according to one of the preceding claims, comprising: comparing the classified material composition with reference data from the database (500), marking the partial area of ​​the vehicle tire or the entire vehicle tire based on the classified material composition with a marking, and sorting the partial area of ​​the vehicle tire or the entire vehicle tire according to predetermined criteria depending on the marking. Method according to one of the preceding claims, wherein the measurement of the received fluorescence radiation is carried out using a hyperspectral sensor (410) so that a fluorescence spectrum is generated for each measured section. Method according to one of the preceding claims, wherein the sample body (200) is moved relative to the laser (300) and to the sensor device (400). Method according to one of the preceding claims, wherein the provision of the sample body (200) comprises cutting the sample body (200) into a compact rubber body (210) and / or granulating the sample body (200) into a rubber granulate (220). Device (100) configured to perform the steps of the method according to one of the preceding claims for analyzing a material composition of a vehicle tire, comprising: - a sample holder (250) for a sample body (200), - a laser (300) for exciting the sample body (200), - a sensor device (400) for measuring fluorescence radiation and recording a fluorescence spectrum of the excited sample body (200), and - a database (500) for storing a multidimensional image of the recorded fluorescence spectrum, wherein each pixel of the multidimensional image contains a fluorescence spectrum, wherein the database (500) contains reference data with predefined material compositions of vehicle tires that are assigned to a defined fluorescence spectrum.

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