Sensor device and method for characterizing metal fragments

Abstract

The present invention relates to a sensor device for characterizing debris, comprising a debris analysis range, the debris analysis range being a spatial region, a signal generator with at least one transmitting coil, the signal generator configured to generate an electric excitation signal and to couple said signal as a magnetic signal to the debris analysis range using the transmitting coil, and a debris classifier with at least one receiving coil, the debris classifier configured to receive a debris signal from the debris analysis range using the receiving coil, the debris signal being a magnetization signal excited by the excitation signal and generated by at least one debris to be classified. The present invention further relates to a method for characterizing debris using a sensor device comprising at least one signal generator and a debris classifier.

Description

Technical Field

[0001] The present invention relates to a sensor device for characterizing debris. The present invention further relates to a method for characterizing debris using the sensor device.

Background Art

[0002] Transmission devices are basically known. Transmission devices serve to transmit and convert motion, energy, and / or force and are used for this purpose in various technical systems such as wind power plants, ships, helicopters, cable cars, or vehicles.

[0003] Therefore, since transmission devices are mechanically loaded when transmitting and converting motion, energy, and / or force, they are known to experience wear in actual use. In order to reduce wear, functionally important components such as gears or rolling bearings are lubricated for the purpose of reducing mechanical wear in the transmission device and achieving a hydrodynamic lubrication state to protect the transmission device from overheating.

[0004] The hydrodynamic lubrication state cannot always be guaranteed during operation, for example, due to dynamic loads and start-up and braking processes, and as a result, the components within the transmission device experience wear. Therefore, various damages such as pitting damage, micropitting, or gouging occur in the gears and in the rolling or plain bearings. The damage or failure modes thereby conform to various standards (for example, DIN 3979). As defined in the above standards, wear is understood to be the abrasion of material by rubbing two objects together. This damage is hereinafter referred to as wear.

[0005] The worn or separated transmission device material therefore enters the lubrication circuit and exists in the lubrication circuit as artifacts in the form of metal particles or metal debris. In addition, other floating substances or different phases such as non-metallic particles containing soot or air bubbles may also be present in the lubrication circuit.

[0006] Since the maintenance and repair of power transmission systems are sometimes associated with considerable effort, such maintenance work or repairs can occasionally lead to prolonged downtime that results in high costs. In addition, for some technical systems, such as helicopters, where wear is monitored with particular rigor, a high level of operational reliability is desired.

[0007] For this reason, attempts are made to monitor the power transmission system.

[0008] One known type of monitoring of transmission devices is known as a particle counter for counting the number of metal wear particles on transmission components. The particle counter uses either an optical or electrical method. When the electrical method is used, an electric field is induced in the lubrication line, for example, to count the metal fragments.

[0009] The challenge with such systems, however, is that they essentially only allow for quantitative conclusions about wear, not conclusions about the type of wear or any kind of transmission damage. The number of particles counted in a lubrication circuit is therefore merely a quantitative indicator that can be used to draw conclusions about transmission damage.

[0010] In addition, the above system relies on wear particles that move (circulating lubrication) so that they are detected by a particle counter.

[0011] Regarding the optical system, the problem is that the system cannot detect particles in dark oil, and therefore can only function or distinguish between metal particles, bubbles, or soot to a limited extent in dark oil.

[0012] To improve the safety, predictability, and cost-effectiveness of technical systems with power transmission devices, it would be desirable not only to quantitatively verify wear using particle counting, but also to qualitatively evaluate wear and distinguish between severe and non-severe wear signs. Currently, this is only possible through laboratory tests or on-site "estimations" by experts.

[0013] The German Patent and Trademark Office has investigated the following prior art: EP1933129B1, EP2121203B1, EP3349000A1, DE102010011936A1, WO2015 / 140411A2, and EP2455774A1. Publications EP1933129B1 and EP3349000A1 relate to apparatus and method for characterizing metal particles by comparing the change in impedance between a measuring coil and a reference coil brought about by the metal particles. Publication EP2121203B1 identifies metal objects on a conveyor belt in which the unmagnetically affected state of the coil is compared to the magnetically affected state. Publications DE102010011936A1 and WO2015140411A2 relate to measuring apparatus for analyzing a sample in a sample container. Publication EP2455774A1 relates to a sensor device having a debris collector with a permanent magnet. When the attractive effect of the permanent magnet is neutralized, an inductive coil is used to generate a counter field, which can release the magnetically held debris. [Prior art documents] [Patent Documents]

[0014] [Patent Document 1] EP1933129B1 [Patent Document 2] EP2121203B1 [Patent Document 3] EP3349000A1 [Patent Document 4] DE102010011936A1 [Patent Document 5] WO2015 / 140411A2 [Patent Document 6] EP2455774A1 [Overview of the project] [Problems that the invention aims to solve]

[0015] The object of the present invention is therefore to address one of the problems described above, to improve the general state of the art, or to provide an alternative to the prior art. In particular, a solution will be provided that enables continuous monitoring and evaluation of debris so that, in addition to detecting debris, the potential risk of wear can be assessed in the field and during operation. [Means for solving the problem]

[0016] According to the present invention, a sensor device according to claim 1 is proposed, providing a sensor device for characterizing fragments. Characterization means that the properties of the fragment, such as the hardness of the fragment, the fragment size, i.e., its volume, or the material from which the fragment is made, are identified or determined using the sensor device. Hardness may also be interpreted synonymously as hardness class. Characterization may also be interpreted as analysis of the fragment. Therefore, it is proposed that fragments be characterized and evaluated using the sensor device in-situ and during operation. Fragments are, for example, particles separated from transmission components. Fragments can therefore be understood as metal particles or metal contaminants. Fragments can also be synonymously referred to as flakes.

[0017] The fragments are preferably metal fragments or metallic fragments.

[0018] The sensor device includes a fragment analysis range, which is a spatial region. The fragment analysis range defines the spatial region in which fragment characterization and analysis are performed. For example, to provide steady-state analysis of fragments within the analysis range, fragments may be held within the analysis range by a fragment collector for this purpose. The fragment analysis range is, for example, a spatial division within a lubrication line in a lubrication oil circuit of a power transmission, or a spatial division within a coolant line in a coolant circuit.

[0019] Furthermore, the sensor device includes a signal generator having at least one transmission coil, and the signal generator is configured to generate an electrical excitation signal and couple the signal into the fragment analysis range using the transmission coil.

[0020] Therefore, it is proposed to generate an electrical signal using a signal generator, for example, having a function generator conductively connected to the transmission coil as a signal source. The electrical excitation signal may be an alternating current signal, for example, a sine wave signal. The transmission coil is, for example, a copper coil wound around a magnetic core. The transmission coil may be interpreted as synonymous with an excitation coil. The coupling may also be interpreted as induction. Therefore, it is proposed to guide an electromagnetic signal into the fragment analysis range where one or more fragments are located. One or more fragments are thus excited by the excitation signal coupled into the fragment analysis range as a magnetic signal. The signal generator having the transmission coil may thus also be interpreted as a transmission unit for guiding an electrical or magnetic signal into the fragment analysis range in order to electrically or magnetically excite the fragments.

[0021] The sensor device further includes a fragment classifier having at least one receiving sensor, and the fragment classifier is configured to receive a fragment signal from the fragment analysis range using the receiving sensor. The fragment signal is a magnetization signal generated by at least one fragment that is excited and classified by the excitation signal. The receiving sensor is, for example, a receiving coil, a receiving element (Hall effect sensor) configured to utilize the Hall effect to receive the fragment signal, a receiving element (magnetoresistive sensor) configured to utilize the magnetoresistive effect to receive the fragment signal, and the like. Therefore, it is proposed to measure the fragment signal using the receiving sensor.

[0022] Preferably, the sensor device includes a fragment classifier having at least one receiving sensor, and the fragment classifier is configured to receive a fragment signal from the fragment analysis range using the receiving coil. The fragment signal is a magnetization signal generated by at least one fragment that is excited and classified by the excitation signal.

[0023] Therefore, it is proposed to use a debris classifier to receive a magnetic signal, i.e., a debris signal, that exits the debris analysis range. The debris signal is a magnetic signal generated by the debris due to its excitation by an excitation signal. As described above, an electromagnetic signal is guided into the debris analysis range using a signal generator and a transmitting coil to electrically or magnetically excite the debris. Due to the above magnetic excitation, the debris preferably generates a measurable signal that is measured with a phase shift relative to the excitation signal, using a receiving coil. The debris signal, for example, induces a voltage in the receiving coil and generates a measurable voltage or a measurable current. The debris classifier may therefore also be interpreted as a receiving or measuring unit for measuring the debris signal, preferably using a receiving coil. The receiving coil may be implemented as a plurality of coils interconnected in an array. One or more receiving coils and / or transmitting coils are, for example, copper-wound coils.

[0024] This basic principle similarly applies to at least one receiving sensor implemented with a receiving element configured to utilize the Hall effect and / or the magnetoresistance effect to receive the debris signal. Due to magnetic excitation, the debris generates a measurable signal, i.e., a debris signal, that is measured with a phase shift from the excitation signal using the receiving element. The debris signal induces a voltage in the receiving element and generates a measurable voltage or a measurable current, or leads to a measurable change in resistance in the receiving element. The debris classifier may therefore also be interpreted as a receiving or measuring unit for measuring the debris signal using a Hall effect sensor and / or a magnetoresistance sensor. A receiving element configured to utilize the Hall effect and / or the magnetoresistance effect to receive the debris signal may also be referred to as a Hall effect sensor and / or a magnetoresistance sensor. The receiving element may be implemented as a plurality of sensors interconnected in an array.

[0025] When there are at least two things or objects, there are multiple things or objects.

[0026] The fragment classifier is further configured to classify at least one fragment within the fragment analysis range by evaluating the phase shift between the excitation signal and the fragment signal and / or the amplitude of the fragment signal.

[0027] Therefore, it is proposed that the fragment classifier also function as an evaluation unit, or that it be equipped with such a unit. The fragment classifier can therefore consider the excitation signal and the fragment signal and determine and / or process the phase shift between the two signals. In addition or alternatively, the fragment classifier can determine and / or process the amplitude of the fragment signal. Phase shift, also known as phase difference or fading, describes two sinusoidal oscillations with shifted phase angles relative to each other, for example, when the period lengths are the same but the zero intercept points are different. The amplitude of the fragment signal describes the maximum deviation of the fragment signal from the position of the arithmetic mean. Amplitude is also known as the peak value.

[0028] Classification, therefore, refers to the fact that the properties of the fragments to be classified will be determined, such as the hardness or hardness class of the fragments, the fragment size, or the fragment material. It is understood that classification also includes detecting fragments. The sensor device is further configured accordingly to detect at least one fragment within the fragment analysis range by evaluating the phase shift between the excitation signal and the fragment signal and / or the amplitude of the fragment signal.

[0029] Preferably, it is proposed that the absolute value of the amplitude of the fragment signal be evaluated or considered in order to characterize the fragment. Therefore, it is proposed that the amplitude be determined as an absolute value.

[0030] It is recognized that metal fragments may exist with various properties, and that these various properties allow for conclusions to be drawn about the extent and / or origin of damage or wear. In particular, it is recognized that the hardness of the fragments is a suitable indicator of whether significant or less significant transmission damage or wear is present.

[0031] By evaluating the phase shift and / or amplitude, conclusions can be drawn about the hardness of the fragments. For example, if magnetically hard fragments are detected, it can then be assumed that critical transmission components have been damaged. Critical transmission components are typically hardened and therefore possess magnetically hard properties. Conversely, if magnetically soft fragments are detected, since magnetically soft metals are used for less critical transmission components, non-critical wear can then be assumed.

[0032] By evaluating the phase shift and / or amplitude, conclusions can be drawn about fragment size in addition to hardness. Fragment size can also be interpreted as fragment volume. If large fragments are detected, conclusions can be drawn about the extent of damage to the transmission components.

[0033] In addition, by evaluating the phase shift and / or amplitude, it is possible to determine the material of the fragments, as fragments made from different materials will have different magnetic properties, such as different magnetic susceptibility.

[0034] Therefore, it is proposed to use the fragments as an indicator of wear in the lubrication circuit of the transmission. Characterization of the fragments, which can also be interpreted synonymously as classification, is performed by evaluating the phase shift between the excitation signal and the fragment signal and / or the amplitude of the fragment signal.

[0035] Intelligent sensors for monitoring the condition of power transmission systems are therefore provided and can be used in various technical systems.

[0036] It should be understood that, in embodiments, evaluation of the phase shift between the excitation signal and the fragment signal and / or the amplitude of the fragment signal is optional for classifying at least one fragment within the fragment analysis range. Other or further evaluation methods may be provided for classifying at least one fragment within the fragment analysis range.

[0037] The fragment classifier is preferably configured to classify at least one fragment within the fragment analysis range as a function of the fragment signal and / or excitation signal using an evaluation method, i.e., at least one evaluation method from the following list of evaluation methods: - Classification using Fourier transforms, such as DFT (Discrete Fourier Transform), FFT (Fast Fourier Transform), or STFT (Short-Term Fourier Transform), using frequency analysis. - Classification using wavelet analysis, - Classification using artificial neural networks.

[0038] The fragment classifier is preferably configured to determine the hardness, fragment size, and / or fragment material of at least one fragment to be classified. The above parameters are determined in such a way that magnetic parameters, such as the area under the hysteresis curve, magnetization, or other magnetic properties, are derived or determined by analyzing the phase shift and / or amplitude of the fragment signal and / or by evaluating them using an evaluation method.

[0039] The receiving sensor is preferably implemented with a receiving coil. A fragment classifier having at least one receiving coil is therefore proposed, the fragment classifier is configured to receive a fragment signal from a fragment analysis range using the receiving coil, the fragment signal being a magnetization signal generated by at least one fragment that will be excited by an excitation signal and classified. The principle of operation using the receiving coil has already been described above. The fragment signal induces a voltage in the receiving coil, generating a measurable voltage or measurable current. The fragment classifier may therefore also be interpreted as a receiving or measuring unit for measuring the fragment signal using the receiving coil.

[0040] The receiving sensor is preferably implemented with a receiving element configured to utilize the Hall effect and / or magnetoresistive effect to receive the fragment signal. The fragment classifier is therefore configured to receive the fragment signal from the fragment analysis range using the Hall effect sensor and / or the magnetoresistive sensor. Therefore, it is proposed to use the Hall effect sensor and / or magnetoresistive sensor as a receiver for the fragment signal in addition to or alternative to the receiving coil. The Hall effect and magnetoresistive effect are basically known. Therefore, it is proposed to use a sensor for measuring a magnetic field or magnetic signal by utilizing the Hall effect and / or magnetoresistive effect. The fragment signal from the fragment analysis range is therefore measured using the Hall effect sensor and / or magnetoresistive sensor, and the fragment signal is a magnetization signal generated by at least one fragment that will be excited by an excitation signal and classified. Combinations of the receiving coil, Hall effect sensor and / or magnetoresistive sensor may also be provided.

[0041] Preferably, the fragment classifier evaluates the in-phase component to identify the fragment size and / or fragment material of the fragment, and it is proposed that this component is further proportional to the fragment's magnetization. The so-called in-phase component is determined by signal processing, in which case the demodulation of the excitation signal and the fragment signal is performed for the original fading (in-phase). It is recognized here that the in-phase component is proportional to the fragment's magnetization. Thus, conclusions can be drawn about the fragment size and / or fragment material from the magnetization.

[0042] Preferably, the fragment classifier evaluates heterophase components to identify the hardness and / or material of the fragment, and it is proposed that these components are further proportional to the area under the fragment's hysteresis curve. The so-called heterophase component is also known from signal processing and is determined in that the demodulation of the excitation signal and the fragment signal is performed at a fixed, phase-shifted reference frequency. The heterophase component is also known as the "orthogonal phase". It is recognized here that the heterophase component is proportional to the area under the fragment's hysteresis curve. It is also recognized that the area under the hysteresis curve allows conclusions to be drawn about the hardness of the fragment. For example, a narrow hysteresis curve with a large saturation magnetization is an indicator of low hardness (magnetically soft), while a broad and shallower hysteresis curve is an indicator of relatively higher hardness (magnetically hard). Therefore, for example, various hardness classes can be determined by evaluating the heterophase component.

[0043] It is understood that in-phase and out-of-phase components can be determined from the excitation signal and / or fragment signal, for example, using frequency analysis.

[0044] Therefore, it is proposed to use the I&Q method (in-phase and perpendicular phase method) to obtain phase information using the above demodulation.

[0045] Preferably, the excitation signal may be an AC voltage signal, such as a sinusoidal, triangular, or rectangular AC voltage signal. The use of an AC voltage signal as the excitation signal is advantageous because the fragment signal is repeatedly excited by the AC voltage signal, allowing the signal to be measured multiple times and with phase shifts. The AC voltage signal may also be implemented as an AC current signal.

[0046] In one further embodiment, it is proposed that the excitation signal has a frequency within a frequency range of 100 Hz to 10 kHz. This frequency range also allows for adjustment of the penetration depth of the excitation signal, so that the fragment signal can be adjusted whenever, for example, the above signal is not sufficiently measurable.

[0047] Preferably, it is proposed that the frequency of the excitation signal be changed in a predetermined sequence to vary the penetration depth of the excitation signal into the fragment. Therefore, rather than operating at a constant frequency, the excitation signal is proposed to undergo frequency changes. In a specific example, a first frequency is set for a first period, then the frequency is changed, and a second frequency is set for a second period. Thus, the penetration depth of the excitation signal into the fragment as a magnetic signal can also be adjusted.

[0048] In a preferred embodiment, the signal generator is configured to generate an electrical excitation signal having a sinusoidal curve and / or triangular curve and / or rectangular curve to set the penetration depth of the excitation signal into the fragment. Since sinusoidal signals are less likely to induce harmonics in the fragment signal, the electrical excitation signal is particularly preferably implemented having a sinusoidal curve.

[0049] Preferably, the fragment classifier is provided with a material database, and material data is stored in the material database.

[0050] In one particularly preferred embodiment, material data is provided here as comparative data, such as coercivity, magnetic susceptibility, remanent magnetism, and magnetic saturation or hysteresis curves. The material data is implemented so that it can be interpolated and stored in a memory unit as a dataset. The memory for the material data may be part of the fragment classifier or an external database. In the latter case, it is understood that the fragment classifier is configured to read from the external database accordingly.

[0051] More preferably, the fragment classifier is configured to determine at least one first hardness class and / or one second hardness class of the fragment by comparison with material data. The first hardness class may be a hardness class indicating that the classified fragment is magnetically soft. The second hardness class may be a hardness class indicating that the classified fragment is magnetically hard. Further intermediate stages of hardness classes may also be provided.

[0052] In addition or alternatively, it is proposed that the fragment classifier be configured to determine at least one fragment size of a fragment by comparing it with material data. Fragment size may also be interpreted as volume, as described above. For example, fragment size can be determined from the comparison data described above.

[0053] In addition, or alternatively, preferably, the fragment classifier is proposed to be configured to determine at least one fragment material of the fragment by comparing it with material data. The fragment material describes the material from which the fragment is formed, such as hardened steel.

[0054] Material data preferably includes at least one comparison signal curve. Therefore, it is proposed that at least one comparison signal curve is part of the material data, and that the acquired fragment signal can be compared with the comparison signal curve. Multiple comparison signal curves may be stored in the material data and may be interpreted as a property map. Accordingly, it is proposed to classify fragments that fall within the fragment analysis range by comparing them with at least one comparison signal curve, for example, to determine the fragment's hardness, fragment size, or fragment material.

[0055] In one particularly preferred embodiment, it is proposed that the presence of a first and / or second hardness class is determined by comparing the fragment signal with a comparison signal curve. The fragment classifier is preferably configured to determine the presence of a first and / or second hardness class by comparing the fragment signal with a comparison signal curve.

[0056] In a preferred embodiment, it is proposed that the fragment classifier be implemented with a plurality of receiving coils, the receiving coils being distributed across the sensor surface within the sensor head. In addition or alternatively, it is proposed that the fragment classifier be implemented with a plurality of Hall effect sensors and / or magnetoresistive sensors, the Hall effect sensors and / or magnetoresistive sensors being distributed across the sensor surface within the sensor head. By using a plurality of receiving coils, the location of the fragments can be determined and provided. By using a plurality of Hall effect sensors and / or magnetoresistive sensors, the location of the fragments can also be determined and provided. The location determination relates to the location of the fragments on the sensor head. The location determination is provided to detect a plurality of different fragments in order to provide independent characterization of the different fragments located on the sensor head.

[0057] By using multiple receiving coils, the size of the fragment can be additionally or alternatively determined and provided. Additionally, by using multiple Hall effect sensors and / or magnetoresistive sensors, the size of the fragment can also be additionally or alternatively determined and provided. For example, when a fragment is located across multiple receiving coils, the fragment size can be determined by evaluating the fragment signal from the receiving coil located near the fragment to be classified. The reflected fragment signal is strongest at that point.

[0058] For this purpose, the coils can be interconnected as an array and read out individually using a selection circuit, for example, a multiplexer.

[0059] For example, when a fragment is located across multiple Hall effect sensors and / or magnetoresistive sensors, the fragment size can be determined by evaluating the fragment signals from Hall effect sensors and / or magnetoresistive sensors located near the fragment to be classified. The reflected fragment signal is strongest at that point.

[0060] Hall effect sensors and / or magnetoresistive sensors can be interconnected as an array for this purpose and read individually using a selection circuit, for example, a multiplexer or bus system.

[0061] The receiving coils are preferably arranged in a honeycomb pattern within the sensor head. In addition or alternatively, Hall effect sensors and / or magnetoresistive sensors are arranged in a chessboard pattern within the sensor head, i.e., adjacent to each other rectangularly in two directions, like a chessboard. The mounting density can thus be increased.

[0062] At least one receiving coil preferably has a coil axis mounted substantially perpendicular to the sensor plane. This orientation relative to the sensor plane allows for minimizing the influence of the excitation signal on the debris signal. Using this arrangement, an excitation field is generated that is directed perpendicular to the receiving coil. The influence of the excitation signal on the receiving coil is therefore minimized. In addition or alternatively, at least one Hall effect sensor and / or magnetoresistive sensor may have at least one sensor axis mounted perpendicular to the sensor plane, in particular to minimize the influence of the excitation signal on the debris signal. It is therefore proposed that the Hall effect sensor and / or magnetoresistive sensor be directed so as not to measure the excitation signal as possible, or so that at least one axis of at least a multi-axis sensor does not measure the excitation signal as much as possible. In one preferred embodiment, at least one Hall effect sensor and / or at least one magnetoresistive sensor is mounted having multiple axes, particularly three axes. The influence of the excitation signal on the receiving coil is therefore minimized.

[0063] The sensor device preferably includes a fragment collector to hold at least one fragment to be classified within the fragment analysis range. Therefore, it is proposed that the device be provided to hold one or more fragments to be classified stationary within the fragment analysis range. This may also be interpreted as acquiring one or more fragments.

[0064] In a preferred embodiment, it is proposed that the debris collector is configured to magnetically hold at least one fragment to be classified within the debris analysis range using a magnetic field. For this purpose, the debris collector may be implemented as a coil, for example, to which a direct current is supplied. The debris collector may also be implemented with a magnet, such as a permanent magnet.

[0065] In addition or alternatively, in one preferred embodiment, the debris collector is configured to magnetically hold at least one fragment to be classified within the debris analysis range using a magnetic field. For this purpose, the debris collector may be implemented with a metal mesh or with a basket or net.

[0066] Preferably, the debris collector is proposed to be configured as a coil driven by a DC current to magnetically hold at least one fragment to be classified within the debris analysis range using a magnetic field. Using a coil driven by a DC current allows for the advantageous implementation of an adjustable magnetic field. The magnetic collector can therefore be switched off as needed.

[0067] In a further preferred embodiment, the magnetic field is implemented so that it can be switched on and off using a control unit. This allows, for example, the cleaning of the debris area. For maintenance, the magnetic field of the debris collector can be switched off. After being switched off, the debris is no longer magnetically held by the debris collector and can therefore be easily removed.

[0068] The fragment analysis range is preferably the spatial area within a liquid flow line. Therefore, it is proposed that sensor devices can be installed and used in all liquid flow lines, such as lubrication or cooling circuits.

[0069] The aforementioned sensor device can be introduced into any line through which liquid flows accordingly.

[0070] In one preferred embodiment, the liquid is an oil and / or liquid coolant, and the line is more preferably a lubrication and / or coolant line.

[0071] Preferably, it is proposed that the fragment classifier be configured to provide fragment signals to an external processing unit using a communication unit for external evaluation.

[0072] Preferably, the fragment classifier is configured to provide evaluation results using a communication unit, the evaluation results being, in particular, a classified hardness class, a classified fragment size, and / or a classified fragment material. The evaluation or classification results can therefore be further processed and provided, for example, to a process computer for process monitoring, or to be analyzed using an analysis unit, or to a reporting unit to indicate the need for maintenance or repair.

[0073] The signal generator is preferably configured to provide an excitation signal as a reference signal to the fragment classifier and / or to the external processing unit using a communication unit.

[0074] The external processing unit is, for example, an external process computer or an external control unit. The external process computer or external control unit may be part of the technical system in which the sensor device is used.

[0075] Preferably, the fragment classifier is proposed to include a calculator for classifying at least one fragment within the fragment analysis range by evaluating the phase shift between the excitation signal and the fragment signal and / or the amplitude of the fragment signal, and / or for classifying at least one fragment within the fragment analysis range as a function of the fragment signal and / or the excitation signal using an evaluation method.

[0076] The arithmetic unit may be an internal arithmetic unit, such as a microcontroller, as part of the sensor device. Alternatively, the arithmetic unit may be an external arithmetic unit, such as an external process computer or external control unit.

[0077] According to the present invention, a method for characterizing fragments is also proposed using a sensor device comprising at least one signal generator and one fragment classifier.

[0078] The method comprises the steps of generating an electrically excited signal using a signal generator having a transmitting coil, wherein the signal generator is configured to generate an electrically excited signal and to couple the signal to a fragment analysis range using a transmitting coil, and the fragment analysis range is a spatial region. A step of receiving a fragment signal using a fragment classifier having at least one receiving sensor, wherein the fragment classifier is configured to receive a fragment signal from a fragment analysis range using the receiving sensor, and the fragment signal is a magnetization signal generated by at least one fragment that will be excited by an excitation signal and classified; A step of evaluating a fragment signal using a fragment classifier, wherein the fragment classifier is configured to classify at least one fragment within a fragment analysis range by evaluating the phase shift between an excitation signal and a fragment signal and / or the amplitude of the fragment signal.

[0079] In one particularly preferred embodiment, the sensor device is implemented according to one of the previous embodiments.

[0080] The evaluation step is preferably: A step of determining the fragment size and / or fragment material of a fragment to be classified by determining the in-phase component, preferably proportional to the magnetization of the fragment, using a fragment classifier, and / or Preferably, the method further includes determining at least one hardness class and / or one fragment material of the fragment, which will be classified by determining the heterogeneous components proportional to the area under the hysteresis curve of the fragment.

[0081] The above-described description, advantages, and embodiments of the sensor device for characterizing fragments are similarly applicable to the present method for characterizing fragments using a sensor device.

[0082] The present invention is described in more detail below using embodiments and with reference to the accompanying drawings, in which the same reference numerals are used for the same or similar parts. [Brief explanation of the drawing]

[0083] [Figure 1] This is a schematic diagram of a lubrication circuit for a transmission device having a sensor device in one embodiment. [Figure 2] This is a schematic block diagram of a sensor device according to the present invention in one embodiment. [Figure 3] This is a schematic diagram of a part of a sensor device in one embodiment introduced into a liquid flow line. [Figure 4] This figure schematically shows a partial side cross-sectional view of a sensor device having a primary coil and multiple receiving coils in one embodiment. [Figure 5] This figure schematically shows a partial upper cross-sectional view of a sensor device having multiple receiving coils in one embodiment. [Figure 6] These are six figures illustrating the evaluation of the phase shift between the excitation signal and the fragment signal, and the evaluation of the amplitude of the fragment signal. [Figure 7] This diagram schematically shows two hysteresis curves. [Figure 8] This is a schematic flowchart of the method according to the present invention in one embodiment. [Modes for carrying out the invention]

[0084] Figure 1 shows a lubrication circuit 10 of a transmission device 11 having a sensor device 100 in one embodiment. The transmission device 11 is shown as a spur gear transmission device for illustrative purposes.

[0085] Pump 12 is part of the lubrication circuit 10 and is configured to pump lubricating oil 13 through the circuit. The lubricating oil 13 is provided to reduce wear on the transmission 11 and to reduce mechanical friction in the illustrated spur gear transmission. Mechanical load on the transmission may cause signs of wear, such as surface pitting or ablation from the transmission components. Worn or separated transmission material then enters the lubrication circuit 10 and is present in the lubrication circuit as artifacts in the form of metal particles or metal fragments 14, 15. For example, in Figure 1, two magnetically hard fragments or particles 15 and one magnetically soft fragment or particle 14 are shown, which may have separated at different points in time. In addition, other suspended matter 16, such as non-metallic dust particles, is also present in the lubrication circuit.

[0086] A filter 17 is provided to remove suspended matter 16 from the lubricating oil 13. Metal fragments are filtered by a sensor device 100. The sensor device preferably includes a fragment collector to hold at least one fragment to be classified or fragments 14, 15 to be classified within the fragment analysis range 110.

[0087] A sensor device 100 for characterizing the fragments is part of the lubrication circuit 10. The sensor device 100 is implemented as shown, for example, in Figures 2, 3, 4, or 5. The sensor device 100 is introduced into a liquid-flowing line 18 and comprises a fragment analysis range 110 as a spatial region within the line 18, illustrated as a dotted line.

[0088] The sensor device 100 includes a signal generator (not shown in Figure 1) having at least one transmitting coil, which generates an electrical excitation signal and is configured to couple this signal as a magnetic signal to the fragment analysis range 110 using the transmitting coil. The coupling of the excitation signal as a magnetic signal to the fragment analysis range 110 is depicted by the lines of force shown in Figure 1.

[0089] Figure 1 illustrates the lubrication circuit 10 of a spur gear transmission. The illustrated sensor device 100 may, however, be introduced into any other line 18 through which a liquid flows. The functional principle of the sensor device 100 is not limited to the lubrication circuit 10 of the transmission, but rather it may be introduced, for example, into a coolant circuit or directly into the transmission.

[0090] Figure 2 schematically shows a block circuit diagram of the sensor device 100, such as the one illustrated in Figure 1.

[0091] The sensor device 100 is provided for characterizing fragments 14, 15 and comprises a fragment analysis range 110, which is a spatial region within a liquid-flowing line 18, as shown in Figure 1, for example.

[0092] The sensor device 100 includes a signal generator 200 having at least one transmitting coil 210, the signal generator being configured to generate an electrical excitation signal 220 and to couple the signal to the fragment analysis range 110 as a magnetic signal 230 using the transmitting coil 210. The electrical excitation signal 220 may be generated using a function generator 240 as a sinusoidal AC voltage signal at a frequency within a frequency range of 100 Hz to 10 kHz, for example. The frequency of the excitation signal 220 can be varied in a predetermined sequence to adjust the penetration depth into the fragments 14, 15 in this case.

[0093] An amplifier 250 may also be provided to amplify the electrical excitation signal 220.

[0094] The electrical excitation signal 220 is converted into a magnetic signal 230 in the transmitting coil and thus coupled to the fragment analysis range 110. The magnetic signal 230 magnetically excites the fragments 14 and 15, and as a result, a characteristic and measurable fragment signal 260 is generated based on the excitation by the magnetic signal 230.

[0095] The sensor device further comprises a fragment classifier 300 having at least one receiving sensor 310, the fragment classifier 300 configured to receive fragment signals 260 from a fragment analysis range 110 using a receiving coil. The receiving coil may therefore also be interpreted as a measuring coil. The fragment signal 260 is a magnetization signal generated by at least one fragment 14, 15 which is excited by an excitation signal and to be classified.

[0096] In addition to or alternative to the receiving coil, at least one Hall effect sensor and / or one magnetoresistive sensor may be used. The use of a receiving coil is illustrated in the embodiment.

[0097] The fragment classifier 300 is configured to classify at least one fragment 14, 15 within the fragment analysis range 110 by evaluating the phase shift between the excitation signal 220 and the fragment signal 260 and / or the amplitude of the fragment signal 260.

[0098] For example, the fragment classifier 300 evaluates the in-phase component to identify the fragment size and / or fragment material of fragments 14 and 15, and the above component is proportional to the magnetization of the fragments. In addition or alternatively, the fragment classifier 300 evaluates the heterophase component to identify the hardness and / or fragment material of fragments 14 and 15, and the above component is proportional to the area under the hysteresis curve of the fragments, as illustrated as an example in Figures 6 and 7.

[0099] The fragment classifier 300 may also include an amplifier 330 to amplify the fragment signal 260 measured using the receiving coil 310 within a desired operating range.

[0100] If the fragment classifier 300 is implemented with multiple receiving coils 310, and the receiving coils 310 are distributed across the sensor surface within the sensor head to provide a determination of the fragment's position, as illustrated in Figures 4 and 5, then a selection circuit 320, such as a multiplexer, may also be provided to evaluate the multiple receiving coils 310 independently of each other.

[0101] The fragment classifier 300 may also be equipped with a material database 340, in which material data such as coercivity, magnetic susceptibility, remanent magnetism, magnetic saturation, or hysteresis curves are stored.

[0102] The fragment classifier 300 is configured to use the arithmetic unit 350 to determine at least one first hardness class and / or one second hardness class, fragment size, and / or fragment material of fragments 14, 15 by comparing them with material data. Therefore, for example, it can determine whether magnetically soft fragments 14 or magnetically hard fragments 15 are present. Fragment size or fragment volume can also be determined, as can the material of fragments 14 or 15. Conclusions regarding significant or non-significant wear or significant or non-significant transmission damage can then be drawn.

[0103] The arithmetic unit 350 is implemented, for example, as a microcontroller.

[0104] The material database 340 is depicted in Figure 2 as part of the fragment classifier, but it may also be an external database, and the arithmetic unit 350 may communicate with the external database, for example, using a communication module.

[0105] The material data may also include comparison signal curves, meaning that the presence of a first and / or second hardness class is determined by comparing the fragment signal 260 with the comparison signal curves using a computing unit. Therefore, the fragment signal 260 is compared with multiple signal curves stored in the material database 340. For example, the signal curves may be stored in the material database 340 as property maps.

[0106] After the fragment classifier 300 classifies at least one fragment 14, 15 within the fragment analysis range by evaluating the phase shift between the excitation signal 220 and the fragment signal 260 and / or the amplitude of the fragment signal 260, the classification results can be further processed and provided, for example, to a process computer 400 for process monitoring, or to be analyzed using an analysis unit 410, or to a reporting unit 420 to indicate the need for maintenance or repair.

[0107] Figure 3 shows a portion of a sensor device 100 for characterizing fragments, as illustrated in Figure 1 or Figure 2. The sensor device 100 comprises a fragment analysis range 110, preferably a spatial region within a liquid-flowing line 18. The sensor device 100 includes a signal generator (not shown) having at least one transmitting coil. The signal generator is configured to generate an electrically excited signal 220 and to couple this signal to the fragment analysis range 110 as a magnetic signal 230 using a transmitting coil (also not shown).

[0108] The sensor device 100 further comprises a debris collector 270 to hold at least one fragment 14, 15 to be classified in a debris analysis range 110, i.e., stationarily on the sensor head of the sensor device 100. Since multiple metal fragments 14, 15 adhere to the sensor head of the sensor device 100, the debris collector 270 is illustrated only indirectly in Figure 3. The debris collector 270 is configured to magnetically hold at least one fragment to be classified in the debris analysis range 110 using a magnetic field. For this purpose, the debris collector may be configured as a coil driven by a DC current to magnetically hold at least one fragment 14, 15 to be classified in the debris analysis range 110 using a magnetic field, and the magnetic field is implemented to be switched on and off using a control unit to clean the debris range.

[0109] Figure 4 shows a partial side cross-sectional view of a sensor device 100 having a transmitting coil 210 and a plurality of receiving coils 310. The receiving coils are provided distributed across the sensor surface 290 within the sensor head 280 to provide location and / or size determination of the fragments 14, 15.

[0110] The receiving coil 310 includes a coil axis mounted perpendicular to the sensor plane 290 to minimize the influence of the excitation signal on the fragment signal. The transmitting coil 210 in the illustrated embodiment further includes a coil axis mounted substantially parallel to the sensor plane 290. The coil axis of the transmitting coil may alternatively be mounted substantially perpendicular to the sensor plane 290, particularly when the transmitting coil is wound on a vertical arm. Using the above alignment, since the excitation field is perpendicular to the receiving coil, the influence of the excitation signal coupled to the fragment analysis range 110 as a magnetic signal 230 can be reduced, and the fragment signal can be measured in an improved manner.

[0111] Figure 5 shows a portion of a sensor device 100 having multiple receiving coils 310, which are distributed across the sensor surface 290 within the sensor head 280 to provide location and / or size determination of fragments 14, 15, and the receiving coils 310 are distributed in a honeycomb pattern within the sensor head 280. The illustrated Figure 5 is, for example, an upper cross-sectional view of Figure 4.

[0112] Figure 6 illustrates the evaluation principles for characterizing fragments. As described above, the fragment classifier is configured to classify at least one fragment within the fragment analysis range by evaluating the phase shift between the excitation signal and the fragment signal and / or the amplitude of the fragment signal. The fragment classifier is therefore configured to determine, for example, fragment size, fragment material and / or fragment hardness class.

[0113] Three Figures A1 to A3 illustrate the characterization of magnetically soft fragments in the upper region A.

[0114] Figures B1 to B3 illustrate the characterization of magnetically hard fragments in the lower region B.

[0115] Two different hysteresis curves are shown in Figures A1 and B1. In both Figures A1 and B1, magnetization M is plotted on the Y-axis and magnetic field strength H is plotted on the X-axis. The intersections of the curves with the Y-axis correspond to positive and negative remanence. The intersections with the X-axis correspond to positive and negative coercivity. The dotted lines correspond to the progression of the initial magnetization curve. As can be seen, curves A1 and B1 saturate in both positive and negative directions, independently of whether the magnetic field strength is further increased positively or negatively. This is known as magnetic saturation. The two hysteresis curves therefore also include positive and negative magnetic saturation. As can be seen in Figure A1, a narrower hysteresis curve is obtained compared to Figure B1, leading to the conclusion of a soft fragment. The hysteresis curve in Figure B1 is broader and lower compared to Figure A1, resulting in the conclusion of a magnetically hard fragment. This relationship is also illustrated in Figures 6 and 7.

[0116] For example, an electrical excitation signal 220 and a fragment signal 260 are illustrated in Figures A2 and B2. In both Figures A2 and B2, the voltage U is plotted over time t. Voltage curves 220 and 260 are illustrated in the same figure, however the amplitude values ​​of signal curves 220 and 260 may be different.

[0117] As can be seen in Figures A2 and B2, different material properties of the fragments result in different phase shifts between the electrical excitation signal 220 and the fragment signal 260. For example, Figure A2 shows the fragment signal generated by a magnetically soft fragment. Figure B2 illustrates, as an example, the fragment signal generated by a magnetically hard fragment. By evaluating the phase shift, the fragments can therefore be classified, for example, in terms of hardness.

[0118] In addition to or alternative to the phase shift, it is also provided that the amplitude of the fragment signal 260 be evaluated. Since different fragments implement different amplitudes in the fragment signal curve when magnetically excited as a function of the electrical excitation signal, the amplitude of the fragment signal may be used as additional information for the phase shift.

[0119] Figures A3 and B3 essentially show Figures A2 and B2 in different ways, namely as rotating space phasors. As can be seen, space phasors 220 and 260 rotate synchronously with each other at phase angles of various magnitudes. Therefore, the phase shift can also be determined based on the phase angle.

[0120] Figure 7 shows an example of two hysteresis curves plotted on a triaxial plot. Magnetic field strength H is plotted on the X-axis. Magnetic flux density B is plotted on the first Y-axis, and magnetization M is plotted on the second Y-axis.

[0121] As can be seen, magnetically hard and magnetically soft fragments differ by different regions of their hysteresis curves. This realization is used not only to detect fragments within the fragment analysis range, but also to characterize them in terms of, for example, their size (fragment volume), magnetic properties (hardness), or material properties (fragment material).

[0122] Figure 8 shows a flowchart of a method for characterizing fragments using a sensor device.

[0123] In the first step S1, an electrical excitation signal is generated using a signal generator having a transmitting coil. The signal generator is configured to generate an electrical excitation signal and to couple the signal to a fragment analysis range using a transmitting coil, and the fragment analysis range is a spatial region.

[0124] In the second step S2, a fragment signal is received using a fragment classifier having at least one receiving coil, the fragment classifier being configured to receive a fragment signal from the fragment analysis range using the receiving coil, the fragment signal being a magnetization signal generated by at least one fragment which will be excited by an excitation signal and classified.

[0125] In the third step S3, the fragment signal is evaluated using a fragment classifier, which is configured to classify at least one fragment within the fragment analysis range by evaluating the phase shift between the excitation signal and the fragment signal and / or the amplitude of the fragment signal.

[0126] In addition, two more preferred steps S3.1 and S3.2 are exemplified in step S3.

[0127] In step S3.1, a fragment classifier is used to determine the fragment size and / or fragment material of the fragments to be classified by determining the in-phase component that is proportional to the magnetization of the fragments.

[0128] In step 3.2, at least one hardness class and / or one fragment material of the fragment to be classified is determined by determining the heterogeneous components proportional to the area under the hysteresis curve of the fragment.

[0129] As a further consideration, a sensor device for characterizing fragments is proposed, comprising: a fragment analysis range, which is a fragment analysis range and is a spatial region; a signal generator having at least one transmitting unit, the signal generator being configured to generate an electrical excitation signal and to couple the signal to the fragment analysis range using the transmitting unit; and a fragment classifier having at least one receiving sensor, the fragment classifier being configured to receive a fragment signal from the fragment analysis range using the receiving sensor, the fragment signal being a magnetization signal generated by at least one fragment that is excited by the excitation signal and to be classified, wherein the fragment classifier is further configured to classify at least one fragment within the fragment analysis range by evaluating the phase shift between the excitation signal and the fragment signal and / or the amplitude of the fragment signal.

[0130] As an alternative to the transmitting coil, it is therefore proposed to use a signal generator having at least one transmitting unit, wherein the signal generator is configured to generate an electrically excited signal and to couple the signal as a magnetic signal to the fragment analysis range using the transmitting unit. Therefore, it is proposed to use some other arbitrary technical device instead of a transmitting coil to generate the electrically excited signal.

[0131] An optional feature is the use of a signal generator having at least one transmitting coil, wherein the signal generator is configured to generate an electrically excited signal and to couple the signal as a magnetic signal to the fragment analysis range using the transmitting coil. A sensor device that is simply configured to receive a fragment signal and evaluate the fragment signal may also be provided.

[0132] As a further consideration, a sensor device for characterizing fragments is proposed, comprising a fragment classifier having at least one receiving sensor, wherein the fragment classifier is configured to receive a fragment signal using the receiving sensor, the fragment signal being a magnetization signal generated by at least one fragment that is excited by an excitation signal and to be classified, and the fragment classifier is configured to classify at least one fragment by evaluating the phase shift between the excitation signal and the fragment signal and / or the amplitude of the fragment signal.

[0133] The sensor device having a general-purpose transmitting unit or without a signal generator is preferably implemented according to any one of the previous embodiments.

[0134] A method step for generating an electrically excited signal using a signal generator having a transmitting coil, wherein the signal generator is configured to generate an electrically excited signal and to couple the signal to a fragment analysis range using a transmitting coil, and the fragment analysis range is a spatial region, and the method step is an optional feature. A method that is simply configured to receive and evaluate a fragment signal may also be provided.

[0135] As a further consideration, a method is proposed for characterizing fragments using a sensor device comprising at least one fragment classifier. The method includes the steps of: receiving a fragment signal using a fragment classifier having at least one receiving sensor, wherein the fragment classifier is configured to receive an generated fragment signal using the receiving sensor, the fragment signal being a magnetization signal generated by at least one fragment to be excited by an excitation signal and classified; and evaluating the fragment signal using the fragment classifier, wherein the fragment classifier is configured to classify at least one fragment by evaluating the phase shift between the excitation signal and the fragment signal and / or the amplitude of the fragment signal. A measurement method is proposed for this purpose.

[0136] A feature that classifies at least one fragment by evaluating the phase shift between the excitation signal and the fragment signal and / or the amplitude of the fragment signal is therefore an optional feature. It is generally proposed to evaluate the received fragment signal to classify the fragments. It is therefore proposed to evaluate the fragment signal as a magnetic signal generated by excitation and generated in the fragment as a response to the excitation. Known methods for characterizing fragments, in contrast, use a comparison coil to characterize the fragment using the change in impedance between a measuring coil and a reference coil, as described in the introduction above. [Explanation of Symbols]

[0137] 10 Lubrication circuit 11 Transmission device 12 pumps 13 Lubricating oil 14, 15 (metal) fragments (magnetically soft, magnetically hard) 16. Floating objects 17 Filters 18. Liquid flow line 100 Sensor device 110 Fragment Analysis Range 200 signal generators 210 Transmitter coil 220 Excitation signal 230 Magnetic Signals 240 Function Generator 250 Amplifier 260 Fragment Signal 270 Debris Collector 280 Sensor Heads 290 Sensor surface plane 300 Fragment Classifier 310 Receiving coil 320 Selection Circuit 330 Amplifier 340 Materials Database 350 Arithmetic unit 400 Process Computers 410 Analysis Units 420 Reporting Units

Claims

1. A sensor device (100) for characterizing fragments (14, 15), - Fragment analysis range (110), and the fragment analysis range is a spatial region, - A signal generator (200) having at least one transmitting coil (210), wherein the signal generator is configured to generate an electrically excited signal (220) and to couple the signal as a magnetic signal (230) to the fragment analysis range using the transmitting coil, - A fragment classifier (300) having at least one receiving sensor (310), wherein the fragment classifier is configured to receive a fragment signal (260) from the fragment analysis range using the receiving sensor, and the fragment signal is a magnetization signal generated by at least one fragment (14, 15) that is excited by the excitation signal and classified, in a sensor device comprising: The fragment classifier (300) is further configured to classify the at least one fragment (14, 15) within the fragment analysis range (110) by evaluating the phase shift between the excitation signal (220) and the fragment signal (260) and / or the amplitude of the fragment signal (260). The transmitting coil is separate from the receiving sensor. The sensor device is characterized in that the hardness of the fragment is determined based on the phase shift, or preferably on a different phase component that is proportional to the area under the hysteresis curve of the fragment.

2. The sensor device (100) according to claim 1, wherein the receiving sensor having a receiving coil for receiving the fragment signal is mounted.

3. The sensor device (100) according to claim 1 or 2, wherein the receiving sensor is mounted having a receiving element configured to utilize the Hall effect and / or magnetoresistive effect to receive the fragment signal.

4. The sensor device (100) according to claim 1 or 2, wherein the fragment classifier (300) evaluates in-phase components to identify the fragment size and / or fragment material of the fragment, and the components are preferably proportional to the magnetization of the fragment.

5. The sensor device (100) according to claim 1 or 2, wherein the fragment classifier (300) evaluates heterophase components to identify the hardness and / or material of the fragment, and the components are preferably proportional to the area under the hysteresis curve of the fragment.

6. The sensor device (100) according to claim 1 or 2, wherein the excitation signal (220) is an AC voltage signal, particularly a sinusoidal, triangular, or rectangular AC voltage signal.

7. The sensor device (100) according to claim 1 or 2, wherein the excitation signal (220) has a frequency within the frequency range of 100 Hz to 10 kHz.

8. The sensor device (100) according to claim 7, wherein the frequency of the excitation signal (220) is changed in a predetermined sequence to change the penetration depth of the excitation signal into the fragments (14, 15).

9. The sensor device (100) according to claim 1 or 2, wherein the signal generator (200) is configured to generate the electrical excitation signal (220) having a sinusoidal curve and / or triangular curve and / or rectangular curve in order to set the penetration depth of the excitation signal into the fragment.

10. The fragment classifier (300) is equipped with a material database (340), and material data is stored in the material database, and (i) The fragment classifier (300) is configured to determine at least one first hardness class and / or one second hardness class of the fragment by comparing it with the material data, and / or (ii) The fragment classifier (300) is configured to determine at least one fragment size of the fragment by comparing it with the material data, and / or (iii) The sensor device (100) according to claim 1 or 2, wherein the fragment classifier (300) is configured to determine at least one fragment material of the fragment by comparing it with the material data.

11. The sensor device (100) according to claim 10, wherein the material data comprises at least one comparison signal curve, and the presence of the first and / or second hardness class is preferably determined by comparing the fragment signal with the at least one comparison signal curve.

12. The sensor device (100) according to claim 1 or 2, wherein the fragment classifier (300) is implemented having a plurality of receiving coils (310) and / or a plurality of Hall effect sensors and / or a plurality of magnetoresistive sensors, and the receiving coils and / or the Hall effect sensors and / or the magnetoresistive sensors are distributed across a sensor surface (290) within a sensor head (280) in order to provide in particular determination of the position of the fragments and / or determination of the size of the fragments, and the receiving coils and / or the Hall effect sensors and / or the magnetoresistive sensors are preferably distributed within the sensor head in a honeycomb and / or chessboard pattern.

13. The sensor device (100) according to claim 1 or 2, wherein the at least one receiving coil (310) comprises a coil axis, and / or the at least one Hall effect sensor comprises a sensor axis, and / or the at least one magnetoresistive sensor comprises at least one sensor axis mounted perpendicular to the sensor plane, in particular to minimize the influence of the excitation signal on the fragment signal.

14. The sensor device (100) according to claim 1 or 2, further comprising a fragment collector (270) for holding the at least one fragment (14, 15) to be classified in the fragment analysis range (110), wherein the fragment collector is preferably configured to magnetically hold the at least one fragment to be classified in the fragment analysis range using a magnetic field and / or mechanically hold the fragment in the fragment analysis range using a fluid permeable filter structure.

15. The sensor device (100) according to claim 14, wherein the fragment collector (270) is configured as a coil driven by a direct current to magnetically hold the at least one fragment to be classified within the fragment analysis range using a magnetic field, and the magnetic field is preferably implemented to be switched on and off using a control unit, particularly for cleaning the fragment range.

16. The sensor device (100) according to claim 1 or 2, wherein the fragment analysis range (110) is a spatial region within a liquid-flowing line (18), the liquid is preferably an oil and / or liquid coolant, and the line is more preferably a lubrication and / or coolant line.

17. A method for characterizing fragments (14, 15) using a sensor device (100) comprising at least one signal generator (200) and one fragment classifier (300), - Step (S1) of generating an electrical excitation signal (220) using the signal generator (200) having a transmitting coil (210), wherein the signal generator is configured to generate the electrical excitation signal and to couple the signal as a magnetic signal to the fragment analysis range using the transmitting coil, and the fragment analysis range is a spatial region. - Step (S2) of receiving a fragment signal (260) using the fragment classifier (300) having at least one receiving sensor (310), wherein the fragment classifier is configured to receive the fragment signal from the fragment analysis range (110) using the receiving sensor, and the fragment signal is a magnetization signal generated by at least one fragment (14, 15) that will be excited by the excitation signal (220) and classified, - A step (S3) of evaluating the fragment signal (260) using the fragment classifier (300), wherein the fragment classifier is configured to classify the at least one fragment (14, 15) within the fragment analysis range (110) by evaluating the phase shift between the excitation signal (220) and the fragment signal (260) and / or the amplitude of the fragment signal (260), preferably, A method by which the sensor device is implemented according to claim 1 or 2.

18. The aforementioned evaluation step is, - A step of determining the fragment size and / or fragment material of the fragments (14, 15) which will be classified by determining the in-phase component, preferably proportional to the magnetization of the fragment, using the fragment classifier, and / or The method according to claim 17, further comprising the step of determining at least one hardness class and / or one fragment material of the fragments (14, 15), which would be classified by determining the heterogeneous components proportional to the area under the hysteresis curve of the fragments.

19. A sensor device (100) for characterizing fragments (14, 15), - Fragment analysis range (110), and the fragment analysis range is a spatial region, - A signal generator (200) having at least one transmitting unit (210), wherein the signal generator is configured to generate an electrically excited signal (220) and to couple the signal as a magnetic signal (230) to the fragment analysis range using the transmitting unit, - A fragment classifier (300) having at least one receiving sensor (310), wherein the fragment classifier is configured to receive a fragment signal (260) from the fragment analysis range using the receiving sensor, and the fragment signal is a magnetization signal generated by at least one fragment (14, 15) that is excited by the excitation signal and classified, in a sensor device comprising: The fragment classifier (300) is further configured to classify the at least one fragment (14, 15) within the fragment analysis range (110) by evaluating the phase shift between the excitation signal (220) and the fragment signal (260) and / or the amplitude of the fragment signal (260). The transmitting unit is separate from the receiving sensor. The sensor device is characterized in that the hardness of the fragment is determined based on the phase shift, or preferably on a different phase component that is proportional to the area under the hysteresis curve of the fragment.

20. A sensor device (100) for characterizing fragments (14, 15), - A signal generator (200) having at least one transmitting unit (210), - A fragment classifier (300) having at least one receiving sensor (310), wherein the fragment classifier is configured to receive a fragment signal (260) using the receiving sensor, and the fragment signal is a magnetization signal generated by at least one fragment (14, 15) that is excited by an excitation signal and classified, in a sensor device comprising: The fragment classifier (300) is further configured to classify the at least one fragment (14, 15) by evaluating the phase shift between the excitation signal (220) and the fragment signal (260) and / or the amplitude of the fragment signal (260), The transmitting unit is separate from the receiving sensor. The sensor device is characterized in that the hardness of the fragment is determined based on the phase shift, or preferably on a different phase component that is proportional to the area under the hysteresis curve of the fragment.

21. The sensor device (100) according to claim 19 or 20, wherein the sensor device is implemented according to claim 1 or 2.

22. A method for characterizing fragments (14, 15) using a sensor device (100) equipped with at least one fragment classifier (300), - Step (S2) of receiving a fragment signal (260) using the fragment classifier (300) having at least one receiving sensor (310), wherein the fragment classifier is configured to receive the generated fragment signal using the receiving sensor, and the fragment signal is a magnetization signal generated by at least one fragment (14, 15) that will be excited by the excitation signal (220) and classified, - Step (S3) of evaluating the fragment signal (260) using the fragment classifier (300), wherein the fragment classifier is configured to classify the at least one fragment (14, 15) by evaluating the phase shift between the excitation signal (220) and the fragment signal (260) and / or the amplitude of the fragment signal (260), The transmitting unit included in the signal generator is separate from the receiving sensor. A method in which the hardness of the fragment is determined based on the phase shift, or preferably on the area under the hysteresis curve of the fragment, which is proportional to the heterophase component.

23. The method according to claim 22, wherein the sensor device for performing the method is implemented according to claim 1 or 2.

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